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1/*
2 * ring buffer based function tracer
3 *
4 * Copyright (C) 2007-2012 Steven Rostedt <srostedt@redhat.com>
5 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
6 *
7 * Originally taken from the RT patch by:
8 * Arnaldo Carvalho de Melo <acme@redhat.com>
9 *
10 * Based on code from the latency_tracer, that is:
11 * Copyright (C) 2004-2006 Ingo Molnar
12 * Copyright (C) 2004 Nadia Yvette Chambers
13 */
14#include <linux/ring_buffer.h>
15#include <generated/utsrelease.h>
16#include <linux/stacktrace.h>
17#include <linux/writeback.h>
18#include <linux/kallsyms.h>
19#include <linux/seq_file.h>
20#include <linux/notifier.h>
21#include <linux/irqflags.h>
22#include <linux/debugfs.h>
23#include <linux/tracefs.h>
24#include <linux/pagemap.h>
25#include <linux/hardirq.h>
26#include <linux/linkage.h>
27#include <linux/uaccess.h>
28#include <linux/kprobes.h>
29#include <linux/ftrace.h>
30#include <linux/module.h>
31#include <linux/percpu.h>
32#include <linux/splice.h>
33#include <linux/kdebug.h>
34#include <linux/string.h>
35#include <linux/mount.h>
36#include <linux/rwsem.h>
37#include <linux/slab.h>
38#include <linux/ctype.h>
39#include <linux/init.h>
40#include <linux/poll.h>
41#include <linux/nmi.h>
42#include <linux/fs.h>
43#include <linux/sched/rt.h>
44
45#include "trace.h"
46#include "trace_output.h"
47
48/*
49 * On boot up, the ring buffer is set to the minimum size, so that
50 * we do not waste memory on systems that are not using tracing.
51 */
52bool ring_buffer_expanded;
53
54/*
55 * We need to change this state when a selftest is running.
56 * A selftest will lurk into the ring-buffer to count the
57 * entries inserted during the selftest although some concurrent
58 * insertions into the ring-buffer such as trace_printk could occurred
59 * at the same time, giving false positive or negative results.
60 */
61static bool __read_mostly tracing_selftest_running;
62
63/*
64 * If a tracer is running, we do not want to run SELFTEST.
65 */
66bool __read_mostly tracing_selftest_disabled;
67
68/* Pipe tracepoints to printk */
69struct trace_iterator *tracepoint_print_iter;
70int tracepoint_printk;
71
72/* For tracers that don't implement custom flags */
73static struct tracer_opt dummy_tracer_opt[] = {
74 { }
75};
76
77static int
78dummy_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
79{
80 return 0;
81}
82
83/*
84 * To prevent the comm cache from being overwritten when no
85 * tracing is active, only save the comm when a trace event
86 * occurred.
87 */
88static DEFINE_PER_CPU(bool, trace_cmdline_save);
89
90/*
91 * Kill all tracing for good (never come back).
92 * It is initialized to 1 but will turn to zero if the initialization
93 * of the tracer is successful. But that is the only place that sets
94 * this back to zero.
95 */
96static int tracing_disabled = 1;
97
98cpumask_var_t __read_mostly tracing_buffer_mask;
99
100/*
101 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
102 *
103 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
104 * is set, then ftrace_dump is called. This will output the contents
105 * of the ftrace buffers to the console. This is very useful for
106 * capturing traces that lead to crashes and outputing it to a
107 * serial console.
108 *
109 * It is default off, but you can enable it with either specifying
110 * "ftrace_dump_on_oops" in the kernel command line, or setting
111 * /proc/sys/kernel/ftrace_dump_on_oops
112 * Set 1 if you want to dump buffers of all CPUs
113 * Set 2 if you want to dump the buffer of the CPU that triggered oops
114 */
115
116enum ftrace_dump_mode ftrace_dump_on_oops;
117
118/* When set, tracing will stop when a WARN*() is hit */
119int __disable_trace_on_warning;
120
121#ifdef CONFIG_TRACE_ENUM_MAP_FILE
122/* Map of enums to their values, for "enum_map" file */
123struct trace_enum_map_head {
124 struct module *mod;
125 unsigned long length;
126};
127
128union trace_enum_map_item;
129
130struct trace_enum_map_tail {
131 /*
132 * "end" is first and points to NULL as it must be different
133 * than "mod" or "enum_string"
134 */
135 union trace_enum_map_item *next;
136 const char *end; /* points to NULL */
137};
138
139static DEFINE_MUTEX(trace_enum_mutex);
140
141/*
142 * The trace_enum_maps are saved in an array with two extra elements,
143 * one at the beginning, and one at the end. The beginning item contains
144 * the count of the saved maps (head.length), and the module they
145 * belong to if not built in (head.mod). The ending item contains a
146 * pointer to the next array of saved enum_map items.
147 */
148union trace_enum_map_item {
149 struct trace_enum_map map;
150 struct trace_enum_map_head head;
151 struct trace_enum_map_tail tail;
152};
153
154static union trace_enum_map_item *trace_enum_maps;
155#endif /* CONFIG_TRACE_ENUM_MAP_FILE */
156
157static int tracing_set_tracer(struct trace_array *tr, const char *buf);
158
159#define MAX_TRACER_SIZE 100
160static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata;
161static char *default_bootup_tracer;
162
163static bool allocate_snapshot;
164
165static int __init set_cmdline_ftrace(char *str)
166{
167 strlcpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
168 default_bootup_tracer = bootup_tracer_buf;
169 /* We are using ftrace early, expand it */
170 ring_buffer_expanded = true;
171 return 1;
172}
173__setup("ftrace=", set_cmdline_ftrace);
174
175static int __init set_ftrace_dump_on_oops(char *str)
176{
177 if (*str++ != '=' || !*str) {
178 ftrace_dump_on_oops = DUMP_ALL;
179 return 1;
180 }
181
182 if (!strcmp("orig_cpu", str)) {
183 ftrace_dump_on_oops = DUMP_ORIG;
184 return 1;
185 }
186
187 return 0;
188}
189__setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
190
191static int __init stop_trace_on_warning(char *str)
192{
193 if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
194 __disable_trace_on_warning = 1;
195 return 1;
196}
197__setup("traceoff_on_warning", stop_trace_on_warning);
198
199static int __init boot_alloc_snapshot(char *str)
200{
201 allocate_snapshot = true;
202 /* We also need the main ring buffer expanded */
203 ring_buffer_expanded = true;
204 return 1;
205}
206__setup("alloc_snapshot", boot_alloc_snapshot);
207
208
209static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata;
210
211static int __init set_trace_boot_options(char *str)
212{
213 strlcpy(trace_boot_options_buf, str, MAX_TRACER_SIZE);
214 return 0;
215}
216__setup("trace_options=", set_trace_boot_options);
217
218static char trace_boot_clock_buf[MAX_TRACER_SIZE] __initdata;
219static char *trace_boot_clock __initdata;
220
221static int __init set_trace_boot_clock(char *str)
222{
223 strlcpy(trace_boot_clock_buf, str, MAX_TRACER_SIZE);
224 trace_boot_clock = trace_boot_clock_buf;
225 return 0;
226}
227__setup("trace_clock=", set_trace_boot_clock);
228
229static int __init set_tracepoint_printk(char *str)
230{
231 if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
232 tracepoint_printk = 1;
233 return 1;
234}
235__setup("tp_printk", set_tracepoint_printk);
236
237unsigned long long ns2usecs(cycle_t nsec)
238{
239 nsec += 500;
240 do_div(nsec, 1000);
241 return nsec;
242}
243
244/* trace_flags holds trace_options default values */
245#define TRACE_DEFAULT_FLAGS \
246 (FUNCTION_DEFAULT_FLAGS | \
247 TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK | \
248 TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | \
249 TRACE_ITER_RECORD_CMD | TRACE_ITER_OVERWRITE | \
250 TRACE_ITER_IRQ_INFO | TRACE_ITER_MARKERS)
251
252/* trace_options that are only supported by global_trace */
253#define TOP_LEVEL_TRACE_FLAGS (TRACE_ITER_PRINTK | \
254 TRACE_ITER_PRINTK_MSGONLY | TRACE_ITER_RECORD_CMD)
255
256
257/*
258 * The global_trace is the descriptor that holds the tracing
259 * buffers for the live tracing. For each CPU, it contains
260 * a link list of pages that will store trace entries. The
261 * page descriptor of the pages in the memory is used to hold
262 * the link list by linking the lru item in the page descriptor
263 * to each of the pages in the buffer per CPU.
264 *
265 * For each active CPU there is a data field that holds the
266 * pages for the buffer for that CPU. Each CPU has the same number
267 * of pages allocated for its buffer.
268 */
269static struct trace_array global_trace = {
270 .trace_flags = TRACE_DEFAULT_FLAGS,
271};
272
273LIST_HEAD(ftrace_trace_arrays);
274
275int trace_array_get(struct trace_array *this_tr)
276{
277 struct trace_array *tr;
278 int ret = -ENODEV;
279
280 mutex_lock(&trace_types_lock);
281 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
282 if (tr == this_tr) {
283 tr->ref++;
284 ret = 0;
285 break;
286 }
287 }
288 mutex_unlock(&trace_types_lock);
289
290 return ret;
291}
292
293static void __trace_array_put(struct trace_array *this_tr)
294{
295 WARN_ON(!this_tr->ref);
296 this_tr->ref--;
297}
298
299void trace_array_put(struct trace_array *this_tr)
300{
301 mutex_lock(&trace_types_lock);
302 __trace_array_put(this_tr);
303 mutex_unlock(&trace_types_lock);
304}
305
306int filter_check_discard(struct trace_event_file *file, void *rec,
307 struct ring_buffer *buffer,
308 struct ring_buffer_event *event)
309{
310 if (unlikely(file->flags & EVENT_FILE_FL_FILTERED) &&
311 !filter_match_preds(file->filter, rec)) {
312 ring_buffer_discard_commit(buffer, event);
313 return 1;
314 }
315
316 return 0;
317}
318EXPORT_SYMBOL_GPL(filter_check_discard);
319
320int call_filter_check_discard(struct trace_event_call *call, void *rec,
321 struct ring_buffer *buffer,
322 struct ring_buffer_event *event)
323{
324 if (unlikely(call->flags & TRACE_EVENT_FL_FILTERED) &&
325 !filter_match_preds(call->filter, rec)) {
326 ring_buffer_discard_commit(buffer, event);
327 return 1;
328 }
329
330 return 0;
331}
332EXPORT_SYMBOL_GPL(call_filter_check_discard);
333
334static cycle_t buffer_ftrace_now(struct trace_buffer *buf, int cpu)
335{
336 u64 ts;
337
338 /* Early boot up does not have a buffer yet */
339 if (!buf->buffer)
340 return trace_clock_local();
341
342 ts = ring_buffer_time_stamp(buf->buffer, cpu);
343 ring_buffer_normalize_time_stamp(buf->buffer, cpu, &ts);
344
345 return ts;
346}
347
348cycle_t ftrace_now(int cpu)
349{
350 return buffer_ftrace_now(&global_trace.trace_buffer, cpu);
351}
352
353/**
354 * tracing_is_enabled - Show if global_trace has been disabled
355 *
356 * Shows if the global trace has been enabled or not. It uses the
357 * mirror flag "buffer_disabled" to be used in fast paths such as for
358 * the irqsoff tracer. But it may be inaccurate due to races. If you
359 * need to know the accurate state, use tracing_is_on() which is a little
360 * slower, but accurate.
361 */
362int tracing_is_enabled(void)
363{
364 /*
365 * For quick access (irqsoff uses this in fast path), just
366 * return the mirror variable of the state of the ring buffer.
367 * It's a little racy, but we don't really care.
368 */
369 smp_rmb();
370 return !global_trace.buffer_disabled;
371}
372
373/*
374 * trace_buf_size is the size in bytes that is allocated
375 * for a buffer. Note, the number of bytes is always rounded
376 * to page size.
377 *
378 * This number is purposely set to a low number of 16384.
379 * If the dump on oops happens, it will be much appreciated
380 * to not have to wait for all that output. Anyway this can be
381 * boot time and run time configurable.
382 */
383#define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
384
385static unsigned long trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
386
387/* trace_types holds a link list of available tracers. */
388static struct tracer *trace_types __read_mostly;
389
390/*
391 * trace_types_lock is used to protect the trace_types list.
392 */
393DEFINE_MUTEX(trace_types_lock);
394
395/*
396 * serialize the access of the ring buffer
397 *
398 * ring buffer serializes readers, but it is low level protection.
399 * The validity of the events (which returns by ring_buffer_peek() ..etc)
400 * are not protected by ring buffer.
401 *
402 * The content of events may become garbage if we allow other process consumes
403 * these events concurrently:
404 * A) the page of the consumed events may become a normal page
405 * (not reader page) in ring buffer, and this page will be rewrited
406 * by events producer.
407 * B) The page of the consumed events may become a page for splice_read,
408 * and this page will be returned to system.
409 *
410 * These primitives allow multi process access to different cpu ring buffer
411 * concurrently.
412 *
413 * These primitives don't distinguish read-only and read-consume access.
414 * Multi read-only access are also serialized.
415 */
416
417#ifdef CONFIG_SMP
418static DECLARE_RWSEM(all_cpu_access_lock);
419static DEFINE_PER_CPU(struct mutex, cpu_access_lock);
420
421static inline void trace_access_lock(int cpu)
422{
423 if (cpu == RING_BUFFER_ALL_CPUS) {
424 /* gain it for accessing the whole ring buffer. */
425 down_write(&all_cpu_access_lock);
426 } else {
427 /* gain it for accessing a cpu ring buffer. */
428
429 /* Firstly block other trace_access_lock(RING_BUFFER_ALL_CPUS). */
430 down_read(&all_cpu_access_lock);
431
432 /* Secondly block other access to this @cpu ring buffer. */
433 mutex_lock(&per_cpu(cpu_access_lock, cpu));
434 }
435}
436
437static inline void trace_access_unlock(int cpu)
438{
439 if (cpu == RING_BUFFER_ALL_CPUS) {
440 up_write(&all_cpu_access_lock);
441 } else {
442 mutex_unlock(&per_cpu(cpu_access_lock, cpu));
443 up_read(&all_cpu_access_lock);
444 }
445}
446
447static inline void trace_access_lock_init(void)
448{
449 int cpu;
450
451 for_each_possible_cpu(cpu)
452 mutex_init(&per_cpu(cpu_access_lock, cpu));
453}
454
455#else
456
457static DEFINE_MUTEX(access_lock);
458
459static inline void trace_access_lock(int cpu)
460{
461 (void)cpu;
462 mutex_lock(&access_lock);
463}
464
465static inline void trace_access_unlock(int cpu)
466{
467 (void)cpu;
468 mutex_unlock(&access_lock);
469}
470
471static inline void trace_access_lock_init(void)
472{
473}
474
475#endif
476
477#ifdef CONFIG_STACKTRACE
478static void __ftrace_trace_stack(struct ring_buffer *buffer,
479 unsigned long flags,
480 int skip, int pc, struct pt_regs *regs);
481static inline void ftrace_trace_stack(struct trace_array *tr,
482 struct ring_buffer *buffer,
483 unsigned long flags,
484 int skip, int pc, struct pt_regs *regs);
485
486#else
487static inline void __ftrace_trace_stack(struct ring_buffer *buffer,
488 unsigned long flags,
489 int skip, int pc, struct pt_regs *regs)
490{
491}
492static inline void ftrace_trace_stack(struct trace_array *tr,
493 struct ring_buffer *buffer,
494 unsigned long flags,
495 int skip, int pc, struct pt_regs *regs)
496{
497}
498
499#endif
500
501static void tracer_tracing_on(struct trace_array *tr)
502{
503 if (tr->trace_buffer.buffer)
504 ring_buffer_record_on(tr->trace_buffer.buffer);
505 /*
506 * This flag is looked at when buffers haven't been allocated
507 * yet, or by some tracers (like irqsoff), that just want to
508 * know if the ring buffer has been disabled, but it can handle
509 * races of where it gets disabled but we still do a record.
510 * As the check is in the fast path of the tracers, it is more
511 * important to be fast than accurate.
512 */
513 tr->buffer_disabled = 0;
514 /* Make the flag seen by readers */
515 smp_wmb();
516}
517
518/**
519 * tracing_on - enable tracing buffers
520 *
521 * This function enables tracing buffers that may have been
522 * disabled with tracing_off.
523 */
524void tracing_on(void)
525{
526 tracer_tracing_on(&global_trace);
527}
528EXPORT_SYMBOL_GPL(tracing_on);
529
530/**
531 * __trace_puts - write a constant string into the trace buffer.
532 * @ip: The address of the caller
533 * @str: The constant string to write
534 * @size: The size of the string.
535 */
536int __trace_puts(unsigned long ip, const char *str, int size)
537{
538 struct ring_buffer_event *event;
539 struct ring_buffer *buffer;
540 struct print_entry *entry;
541 unsigned long irq_flags;
542 int alloc;
543 int pc;
544
545 if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
546 return 0;
547
548 pc = preempt_count();
549
550 if (unlikely(tracing_selftest_running || tracing_disabled))
551 return 0;
552
553 alloc = sizeof(*entry) + size + 2; /* possible \n added */
554
555 local_save_flags(irq_flags);
556 buffer = global_trace.trace_buffer.buffer;
557 event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc,
558 irq_flags, pc);
559 if (!event)
560 return 0;
561
562 entry = ring_buffer_event_data(event);
563 entry->ip = ip;
564
565 memcpy(&entry->buf, str, size);
566
567 /* Add a newline if necessary */
568 if (entry->buf[size - 1] != '\n') {
569 entry->buf[size] = '\n';
570 entry->buf[size + 1] = '\0';
571 } else
572 entry->buf[size] = '\0';
573
574 __buffer_unlock_commit(buffer, event);
575 ftrace_trace_stack(&global_trace, buffer, irq_flags, 4, pc, NULL);
576
577 return size;
578}
579EXPORT_SYMBOL_GPL(__trace_puts);
580
581/**
582 * __trace_bputs - write the pointer to a constant string into trace buffer
583 * @ip: The address of the caller
584 * @str: The constant string to write to the buffer to
585 */
586int __trace_bputs(unsigned long ip, const char *str)
587{
588 struct ring_buffer_event *event;
589 struct ring_buffer *buffer;
590 struct bputs_entry *entry;
591 unsigned long irq_flags;
592 int size = sizeof(struct bputs_entry);
593 int pc;
594
595 if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
596 return 0;
597
598 pc = preempt_count();
599
600 if (unlikely(tracing_selftest_running || tracing_disabled))
601 return 0;
602
603 local_save_flags(irq_flags);
604 buffer = global_trace.trace_buffer.buffer;
605 event = trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size,
606 irq_flags, pc);
607 if (!event)
608 return 0;
609
610 entry = ring_buffer_event_data(event);
611 entry->ip = ip;
612 entry->str = str;
613
614 __buffer_unlock_commit(buffer, event);
615 ftrace_trace_stack(&global_trace, buffer, irq_flags, 4, pc, NULL);
616
617 return 1;
618}
619EXPORT_SYMBOL_GPL(__trace_bputs);
620
621#ifdef CONFIG_TRACER_SNAPSHOT
622/**
623 * trace_snapshot - take a snapshot of the current buffer.
624 *
625 * This causes a swap between the snapshot buffer and the current live
626 * tracing buffer. You can use this to take snapshots of the live
627 * trace when some condition is triggered, but continue to trace.
628 *
629 * Note, make sure to allocate the snapshot with either
630 * a tracing_snapshot_alloc(), or by doing it manually
631 * with: echo 1 > /sys/kernel/debug/tracing/snapshot
632 *
633 * If the snapshot buffer is not allocated, it will stop tracing.
634 * Basically making a permanent snapshot.
635 */
636void tracing_snapshot(void)
637{
638 struct trace_array *tr = &global_trace;
639 struct tracer *tracer = tr->current_trace;
640 unsigned long flags;
641
642 if (in_nmi()) {
643 internal_trace_puts("*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n");
644 internal_trace_puts("*** snapshot is being ignored ***\n");
645 return;
646 }
647
648 if (!tr->allocated_snapshot) {
649 internal_trace_puts("*** SNAPSHOT NOT ALLOCATED ***\n");
650 internal_trace_puts("*** stopping trace here! ***\n");
651 tracing_off();
652 return;
653 }
654
655 /* Note, snapshot can not be used when the tracer uses it */
656 if (tracer->use_max_tr) {
657 internal_trace_puts("*** LATENCY TRACER ACTIVE ***\n");
658 internal_trace_puts("*** Can not use snapshot (sorry) ***\n");
659 return;
660 }
661
662 local_irq_save(flags);
663 update_max_tr(tr, current, smp_processor_id());
664 local_irq_restore(flags);
665}
666EXPORT_SYMBOL_GPL(tracing_snapshot);
667
668static int resize_buffer_duplicate_size(struct trace_buffer *trace_buf,
669 struct trace_buffer *size_buf, int cpu_id);
670static void set_buffer_entries(struct trace_buffer *buf, unsigned long val);
671
672static int alloc_snapshot(struct trace_array *tr)
673{
674 int ret;
675
676 if (!tr->allocated_snapshot) {
677
678 /* allocate spare buffer */
679 ret = resize_buffer_duplicate_size(&tr->max_buffer,
680 &tr->trace_buffer, RING_BUFFER_ALL_CPUS);
681 if (ret < 0)
682 return ret;
683
684 tr->allocated_snapshot = true;
685 }
686
687 return 0;
688}
689
690static void free_snapshot(struct trace_array *tr)
691{
692 /*
693 * We don't free the ring buffer. instead, resize it because
694 * The max_tr ring buffer has some state (e.g. ring->clock) and
695 * we want preserve it.
696 */
697 ring_buffer_resize(tr->max_buffer.buffer, 1, RING_BUFFER_ALL_CPUS);
698 set_buffer_entries(&tr->max_buffer, 1);
699 tracing_reset_online_cpus(&tr->max_buffer);
700 tr->allocated_snapshot = false;
701}
702
703/**
704 * tracing_alloc_snapshot - allocate snapshot buffer.
705 *
706 * This only allocates the snapshot buffer if it isn't already
707 * allocated - it doesn't also take a snapshot.
708 *
709 * This is meant to be used in cases where the snapshot buffer needs
710 * to be set up for events that can't sleep but need to be able to
711 * trigger a snapshot.
712 */
713int tracing_alloc_snapshot(void)
714{
715 struct trace_array *tr = &global_trace;
716 int ret;
717
718 ret = alloc_snapshot(tr);
719 WARN_ON(ret < 0);
720
721 return ret;
722}
723EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
724
725/**
726 * trace_snapshot_alloc - allocate and take a snapshot of the current buffer.
727 *
728 * This is similar to trace_snapshot(), but it will allocate the
729 * snapshot buffer if it isn't already allocated. Use this only
730 * where it is safe to sleep, as the allocation may sleep.
731 *
732 * This causes a swap between the snapshot buffer and the current live
733 * tracing buffer. You can use this to take snapshots of the live
734 * trace when some condition is triggered, but continue to trace.
735 */
736void tracing_snapshot_alloc(void)
737{
738 int ret;
739
740 ret = tracing_alloc_snapshot();
741 if (ret < 0)
742 return;
743
744 tracing_snapshot();
745}
746EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
747#else
748void tracing_snapshot(void)
749{
750 WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used");
751}
752EXPORT_SYMBOL_GPL(tracing_snapshot);
753int tracing_alloc_snapshot(void)
754{
755 WARN_ONCE(1, "Snapshot feature not enabled, but snapshot allocation used");
756 return -ENODEV;
757}
758EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
759void tracing_snapshot_alloc(void)
760{
761 /* Give warning */
762 tracing_snapshot();
763}
764EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
765#endif /* CONFIG_TRACER_SNAPSHOT */
766
767static void tracer_tracing_off(struct trace_array *tr)
768{
769 if (tr->trace_buffer.buffer)
770 ring_buffer_record_off(tr->trace_buffer.buffer);
771 /*
772 * This flag is looked at when buffers haven't been allocated
773 * yet, or by some tracers (like irqsoff), that just want to
774 * know if the ring buffer has been disabled, but it can handle
775 * races of where it gets disabled but we still do a record.
776 * As the check is in the fast path of the tracers, it is more
777 * important to be fast than accurate.
778 */
779 tr->buffer_disabled = 1;
780 /* Make the flag seen by readers */
781 smp_wmb();
782}
783
784/**
785 * tracing_off - turn off tracing buffers
786 *
787 * This function stops the tracing buffers from recording data.
788 * It does not disable any overhead the tracers themselves may
789 * be causing. This function simply causes all recording to
790 * the ring buffers to fail.
791 */
792void tracing_off(void)
793{
794 tracer_tracing_off(&global_trace);
795}
796EXPORT_SYMBOL_GPL(tracing_off);
797
798void disable_trace_on_warning(void)
799{
800 if (__disable_trace_on_warning)
801 tracing_off();
802}
803
804/**
805 * tracer_tracing_is_on - show real state of ring buffer enabled
806 * @tr : the trace array to know if ring buffer is enabled
807 *
808 * Shows real state of the ring buffer if it is enabled or not.
809 */
810static int tracer_tracing_is_on(struct trace_array *tr)
811{
812 if (tr->trace_buffer.buffer)
813 return ring_buffer_record_is_on(tr->trace_buffer.buffer);
814 return !tr->buffer_disabled;
815}
816
817/**
818 * tracing_is_on - show state of ring buffers enabled
819 */
820int tracing_is_on(void)
821{
822 return tracer_tracing_is_on(&global_trace);
823}
824EXPORT_SYMBOL_GPL(tracing_is_on);
825
826static int __init set_buf_size(char *str)
827{
828 unsigned long buf_size;
829
830 if (!str)
831 return 0;
832 buf_size = memparse(str, &str);
833 /* nr_entries can not be zero */
834 if (buf_size == 0)
835 return 0;
836 trace_buf_size = buf_size;
837 return 1;
838}
839__setup("trace_buf_size=", set_buf_size);
840
841static int __init set_tracing_thresh(char *str)
842{
843 unsigned long threshold;
844 int ret;
845
846 if (!str)
847 return 0;
848 ret = kstrtoul(str, 0, &threshold);
849 if (ret < 0)
850 return 0;
851 tracing_thresh = threshold * 1000;
852 return 1;
853}
854__setup("tracing_thresh=", set_tracing_thresh);
855
856unsigned long nsecs_to_usecs(unsigned long nsecs)
857{
858 return nsecs / 1000;
859}
860
861/*
862 * TRACE_FLAGS is defined as a tuple matching bit masks with strings.
863 * It uses C(a, b) where 'a' is the enum name and 'b' is the string that
864 * matches it. By defining "C(a, b) b", TRACE_FLAGS becomes a list
865 * of strings in the order that the enums were defined.
866 */
867#undef C
868#define C(a, b) b
869
870/* These must match the bit postions in trace_iterator_flags */
871static const char *trace_options[] = {
872 TRACE_FLAGS
873 NULL
874};
875
876static struct {
877 u64 (*func)(void);
878 const char *name;
879 int in_ns; /* is this clock in nanoseconds? */
880} trace_clocks[] = {
881 { trace_clock_local, "local", 1 },
882 { trace_clock_global, "global", 1 },
883 { trace_clock_counter, "counter", 0 },
884 { trace_clock_jiffies, "uptime", 0 },
885 { trace_clock, "perf", 1 },
886 { ktime_get_mono_fast_ns, "mono", 1 },
887 { ktime_get_raw_fast_ns, "mono_raw", 1 },
888 ARCH_TRACE_CLOCKS
889};
890
891/*
892 * trace_parser_get_init - gets the buffer for trace parser
893 */
894int trace_parser_get_init(struct trace_parser *parser, int size)
895{
896 memset(parser, 0, sizeof(*parser));
897
898 parser->buffer = kmalloc(size, GFP_KERNEL);
899 if (!parser->buffer)
900 return 1;
901
902 parser->size = size;
903 return 0;
904}
905
906/*
907 * trace_parser_put - frees the buffer for trace parser
908 */
909void trace_parser_put(struct trace_parser *parser)
910{
911 kfree(parser->buffer);
912}
913
914/*
915 * trace_get_user - reads the user input string separated by space
916 * (matched by isspace(ch))
917 *
918 * For each string found the 'struct trace_parser' is updated,
919 * and the function returns.
920 *
921 * Returns number of bytes read.
922 *
923 * See kernel/trace/trace.h for 'struct trace_parser' details.
924 */
925int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
926 size_t cnt, loff_t *ppos)
927{
928 char ch;
929 size_t read = 0;
930 ssize_t ret;
931
932 if (!*ppos)
933 trace_parser_clear(parser);
934
935 ret = get_user(ch, ubuf++);
936 if (ret)
937 goto out;
938
939 read++;
940 cnt--;
941
942 /*
943 * The parser is not finished with the last write,
944 * continue reading the user input without skipping spaces.
945 */
946 if (!parser->cont) {
947 /* skip white space */
948 while (cnt && isspace(ch)) {
949 ret = get_user(ch, ubuf++);
950 if (ret)
951 goto out;
952 read++;
953 cnt--;
954 }
955
956 /* only spaces were written */
957 if (isspace(ch)) {
958 *ppos += read;
959 ret = read;
960 goto out;
961 }
962
963 parser->idx = 0;
964 }
965
966 /* read the non-space input */
967 while (cnt && !isspace(ch)) {
968 if (parser->idx < parser->size - 1)
969 parser->buffer[parser->idx++] = ch;
970 else {
971 ret = -EINVAL;
972 goto out;
973 }
974 ret = get_user(ch, ubuf++);
975 if (ret)
976 goto out;
977 read++;
978 cnt--;
979 }
980
981 /* We either got finished input or we have to wait for another call. */
982 if (isspace(ch)) {
983 parser->buffer[parser->idx] = 0;
984 parser->cont = false;
985 } else if (parser->idx < parser->size - 1) {
986 parser->cont = true;
987 parser->buffer[parser->idx++] = ch;
988 } else {
989 ret = -EINVAL;
990 goto out;
991 }
992
993 *ppos += read;
994 ret = read;
995
996out:
997 return ret;
998}
999
1000/* TODO add a seq_buf_to_buffer() */
1001static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
1002{
1003 int len;
1004
1005 if (trace_seq_used(s) <= s->seq.readpos)
1006 return -EBUSY;
1007
1008 len = trace_seq_used(s) - s->seq.readpos;
1009 if (cnt > len)
1010 cnt = len;
1011 memcpy(buf, s->buffer + s->seq.readpos, cnt);
1012
1013 s->seq.readpos += cnt;
1014 return cnt;
1015}
1016
1017unsigned long __read_mostly tracing_thresh;
1018
1019#ifdef CONFIG_TRACER_MAX_TRACE
1020/*
1021 * Copy the new maximum trace into the separate maximum-trace
1022 * structure. (this way the maximum trace is permanently saved,
1023 * for later retrieval via /sys/kernel/debug/tracing/latency_trace)
1024 */
1025static void
1026__update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
1027{
1028 struct trace_buffer *trace_buf = &tr->trace_buffer;
1029 struct trace_buffer *max_buf = &tr->max_buffer;
1030 struct trace_array_cpu *data = per_cpu_ptr(trace_buf->data, cpu);
1031 struct trace_array_cpu *max_data = per_cpu_ptr(max_buf->data, cpu);
1032
1033 max_buf->cpu = cpu;
1034 max_buf->time_start = data->preempt_timestamp;
1035
1036 max_data->saved_latency = tr->max_latency;
1037 max_data->critical_start = data->critical_start;
1038 max_data->critical_end = data->critical_end;
1039
1040 memcpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
1041 max_data->pid = tsk->pid;
1042 /*
1043 * If tsk == current, then use current_uid(), as that does not use
1044 * RCU. The irq tracer can be called out of RCU scope.
1045 */
1046 if (tsk == current)
1047 max_data->uid = current_uid();
1048 else
1049 max_data->uid = task_uid(tsk);
1050
1051 max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
1052 max_data->policy = tsk->policy;
1053 max_data->rt_priority = tsk->rt_priority;
1054
1055 /* record this tasks comm */
1056 tracing_record_cmdline(tsk);
1057}
1058
1059/**
1060 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
1061 * @tr: tracer
1062 * @tsk: the task with the latency
1063 * @cpu: The cpu that initiated the trace.
1064 *
1065 * Flip the buffers between the @tr and the max_tr and record information
1066 * about which task was the cause of this latency.
1067 */
1068void
1069update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
1070{
1071 struct ring_buffer *buf;
1072
1073 if (tr->stop_count)
1074 return;
1075
1076 WARN_ON_ONCE(!irqs_disabled());
1077
1078 if (!tr->allocated_snapshot) {
1079 /* Only the nop tracer should hit this when disabling */
1080 WARN_ON_ONCE(tr->current_trace != &nop_trace);
1081 return;
1082 }
1083
1084 arch_spin_lock(&tr->max_lock);
1085
1086 buf = tr->trace_buffer.buffer;
1087 tr->trace_buffer.buffer = tr->max_buffer.buffer;
1088 tr->max_buffer.buffer = buf;
1089
1090 __update_max_tr(tr, tsk, cpu);
1091 arch_spin_unlock(&tr->max_lock);
1092}
1093
1094/**
1095 * update_max_tr_single - only copy one trace over, and reset the rest
1096 * @tr - tracer
1097 * @tsk - task with the latency
1098 * @cpu - the cpu of the buffer to copy.
1099 *
1100 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
1101 */
1102void
1103update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
1104{
1105 int ret;
1106
1107 if (tr->stop_count)
1108 return;
1109
1110 WARN_ON_ONCE(!irqs_disabled());
1111 if (!tr->allocated_snapshot) {
1112 /* Only the nop tracer should hit this when disabling */
1113 WARN_ON_ONCE(tr->current_trace != &nop_trace);
1114 return;
1115 }
1116
1117 arch_spin_lock(&tr->max_lock);
1118
1119 ret = ring_buffer_swap_cpu(tr->max_buffer.buffer, tr->trace_buffer.buffer, cpu);
1120
1121 if (ret == -EBUSY) {
1122 /*
1123 * We failed to swap the buffer due to a commit taking
1124 * place on this CPU. We fail to record, but we reset
1125 * the max trace buffer (no one writes directly to it)
1126 * and flag that it failed.
1127 */
1128 trace_array_printk_buf(tr->max_buffer.buffer, _THIS_IP_,
1129 "Failed to swap buffers due to commit in progress\n");
1130 }
1131
1132 WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);
1133
1134 __update_max_tr(tr, tsk, cpu);
1135 arch_spin_unlock(&tr->max_lock);
1136}
1137#endif /* CONFIG_TRACER_MAX_TRACE */
1138
1139static int wait_on_pipe(struct trace_iterator *iter, bool full)
1140{
1141 /* Iterators are static, they should be filled or empty */
1142 if (trace_buffer_iter(iter, iter->cpu_file))
1143 return 0;
1144
1145 return ring_buffer_wait(iter->trace_buffer->buffer, iter->cpu_file,
1146 full);
1147}
1148
1149#ifdef CONFIG_FTRACE_STARTUP_TEST
1150static int run_tracer_selftest(struct tracer *type)
1151{
1152 struct trace_array *tr = &global_trace;
1153 struct tracer *saved_tracer = tr->current_trace;
1154 int ret;
1155
1156 if (!type->selftest || tracing_selftest_disabled)
1157 return 0;
1158
1159 /*
1160 * Run a selftest on this tracer.
1161 * Here we reset the trace buffer, and set the current
1162 * tracer to be this tracer. The tracer can then run some
1163 * internal tracing to verify that everything is in order.
1164 * If we fail, we do not register this tracer.
1165 */
1166 tracing_reset_online_cpus(&tr->trace_buffer);
1167
1168 tr->current_trace = type;
1169
1170#ifdef CONFIG_TRACER_MAX_TRACE
1171 if (type->use_max_tr) {
1172 /* If we expanded the buffers, make sure the max is expanded too */
1173 if (ring_buffer_expanded)
1174 ring_buffer_resize(tr->max_buffer.buffer, trace_buf_size,
1175 RING_BUFFER_ALL_CPUS);
1176 tr->allocated_snapshot = true;
1177 }
1178#endif
1179
1180 /* the test is responsible for initializing and enabling */
1181 pr_info("Testing tracer %s: ", type->name);
1182 ret = type->selftest(type, tr);
1183 /* the test is responsible for resetting too */
1184 tr->current_trace = saved_tracer;
1185 if (ret) {
1186 printk(KERN_CONT "FAILED!\n");
1187 /* Add the warning after printing 'FAILED' */
1188 WARN_ON(1);
1189 return -1;
1190 }
1191 /* Only reset on passing, to avoid touching corrupted buffers */
1192 tracing_reset_online_cpus(&tr->trace_buffer);
1193
1194#ifdef CONFIG_TRACER_MAX_TRACE
1195 if (type->use_max_tr) {
1196 tr->allocated_snapshot = false;
1197
1198 /* Shrink the max buffer again */
1199 if (ring_buffer_expanded)
1200 ring_buffer_resize(tr->max_buffer.buffer, 1,
1201 RING_BUFFER_ALL_CPUS);
1202 }
1203#endif
1204
1205 printk(KERN_CONT "PASSED\n");
1206 return 0;
1207}
1208#else
1209static inline int run_tracer_selftest(struct tracer *type)
1210{
1211 return 0;
1212}
1213#endif /* CONFIG_FTRACE_STARTUP_TEST */
1214
1215static void add_tracer_options(struct trace_array *tr, struct tracer *t);
1216
1217static void __init apply_trace_boot_options(void);
1218
1219/**
1220 * register_tracer - register a tracer with the ftrace system.
1221 * @type - the plugin for the tracer
1222 *
1223 * Register a new plugin tracer.
1224 */
1225int __init register_tracer(struct tracer *type)
1226{
1227 struct tracer *t;
1228 int ret = 0;
1229
1230 if (!type->name) {
1231 pr_info("Tracer must have a name\n");
1232 return -1;
1233 }
1234
1235 if (strlen(type->name) >= MAX_TRACER_SIZE) {
1236 pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE);
1237 return -1;
1238 }
1239
1240 mutex_lock(&trace_types_lock);
1241
1242 tracing_selftest_running = true;
1243
1244 for (t = trace_types; t; t = t->next) {
1245 if (strcmp(type->name, t->name) == 0) {
1246 /* already found */
1247 pr_info("Tracer %s already registered\n",
1248 type->name);
1249 ret = -1;
1250 goto out;
1251 }
1252 }
1253
1254 if (!type->set_flag)
1255 type->set_flag = &dummy_set_flag;
1256 if (!type->flags) {
1257 /*allocate a dummy tracer_flags*/
1258 type->flags = kmalloc(sizeof(*type->flags), GFP_KERNEL);
1259 if (!type->flags) {
1260 ret = -ENOMEM;
1261 goto out;
1262 }
1263 type->flags->val = 0;
1264 type->flags->opts = dummy_tracer_opt;
1265 } else
1266 if (!type->flags->opts)
1267 type->flags->opts = dummy_tracer_opt;
1268
1269 /* store the tracer for __set_tracer_option */
1270 type->flags->trace = type;
1271
1272 ret = run_tracer_selftest(type);
1273 if (ret < 0)
1274 goto out;
1275
1276 type->next = trace_types;
1277 trace_types = type;
1278 add_tracer_options(&global_trace, type);
1279
1280 out:
1281 tracing_selftest_running = false;
1282 mutex_unlock(&trace_types_lock);
1283
1284 if (ret || !default_bootup_tracer)
1285 goto out_unlock;
1286
1287 if (strncmp(default_bootup_tracer, type->name, MAX_TRACER_SIZE))
1288 goto out_unlock;
1289
1290 printk(KERN_INFO "Starting tracer '%s'\n", type->name);
1291 /* Do we want this tracer to start on bootup? */
1292 tracing_set_tracer(&global_trace, type->name);
1293 default_bootup_tracer = NULL;
1294
1295 apply_trace_boot_options();
1296
1297 /* disable other selftests, since this will break it. */
1298 tracing_selftest_disabled = true;
1299#ifdef CONFIG_FTRACE_STARTUP_TEST
1300 printk(KERN_INFO "Disabling FTRACE selftests due to running tracer '%s'\n",
1301 type->name);
1302#endif
1303
1304 out_unlock:
1305 return ret;
1306}
1307
1308void tracing_reset(struct trace_buffer *buf, int cpu)
1309{
1310 struct ring_buffer *buffer = buf->buffer;
1311
1312 if (!buffer)
1313 return;
1314
1315 ring_buffer_record_disable(buffer);
1316
1317 /* Make sure all commits have finished */
1318 synchronize_sched();
1319 ring_buffer_reset_cpu(buffer, cpu);
1320
1321 ring_buffer_record_enable(buffer);
1322}
1323
1324void tracing_reset_online_cpus(struct trace_buffer *buf)
1325{
1326 struct ring_buffer *buffer = buf->buffer;
1327 int cpu;
1328
1329 if (!buffer)
1330 return;
1331
1332 ring_buffer_record_disable(buffer);
1333
1334 /* Make sure all commits have finished */
1335 synchronize_sched();
1336
1337 buf->time_start = buffer_ftrace_now(buf, buf->cpu);
1338
1339 for_each_online_cpu(cpu)
1340 ring_buffer_reset_cpu(buffer, cpu);
1341
1342 ring_buffer_record_enable(buffer);
1343}
1344
1345/* Must have trace_types_lock held */
1346void tracing_reset_all_online_cpus(void)
1347{
1348 struct trace_array *tr;
1349
1350 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
1351 tracing_reset_online_cpus(&tr->trace_buffer);
1352#ifdef CONFIG_TRACER_MAX_TRACE
1353 tracing_reset_online_cpus(&tr->max_buffer);
1354#endif
1355 }
1356}
1357
1358#define SAVED_CMDLINES_DEFAULT 128
1359#define NO_CMDLINE_MAP UINT_MAX
1360static arch_spinlock_t trace_cmdline_lock = __ARCH_SPIN_LOCK_UNLOCKED;
1361struct saved_cmdlines_buffer {
1362 unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
1363 unsigned *map_cmdline_to_pid;
1364 unsigned cmdline_num;
1365 int cmdline_idx;
1366 char *saved_cmdlines;
1367};
1368static struct saved_cmdlines_buffer *savedcmd;
1369
1370/* temporary disable recording */
1371static atomic_t trace_record_cmdline_disabled __read_mostly;
1372
1373static inline char *get_saved_cmdlines(int idx)
1374{
1375 return &savedcmd->saved_cmdlines[idx * TASK_COMM_LEN];
1376}
1377
1378static inline void set_cmdline(int idx, const char *cmdline)
1379{
1380 memcpy(get_saved_cmdlines(idx), cmdline, TASK_COMM_LEN);
1381}
1382
1383static int allocate_cmdlines_buffer(unsigned int val,
1384 struct saved_cmdlines_buffer *s)
1385{
1386 s->map_cmdline_to_pid = kmalloc(val * sizeof(*s->map_cmdline_to_pid),
1387 GFP_KERNEL);
1388 if (!s->map_cmdline_to_pid)
1389 return -ENOMEM;
1390
1391 s->saved_cmdlines = kmalloc(val * TASK_COMM_LEN, GFP_KERNEL);
1392 if (!s->saved_cmdlines) {
1393 kfree(s->map_cmdline_to_pid);
1394 return -ENOMEM;
1395 }
1396
1397 s->cmdline_idx = 0;
1398 s->cmdline_num = val;
1399 memset(&s->map_pid_to_cmdline, NO_CMDLINE_MAP,
1400 sizeof(s->map_pid_to_cmdline));
1401 memset(s->map_cmdline_to_pid, NO_CMDLINE_MAP,
1402 val * sizeof(*s->map_cmdline_to_pid));
1403
1404 return 0;
1405}
1406
1407static int trace_create_savedcmd(void)
1408{
1409 int ret;
1410
1411 savedcmd = kmalloc(sizeof(*savedcmd), GFP_KERNEL);
1412 if (!savedcmd)
1413 return -ENOMEM;
1414
1415 ret = allocate_cmdlines_buffer(SAVED_CMDLINES_DEFAULT, savedcmd);
1416 if (ret < 0) {
1417 kfree(savedcmd);
1418 savedcmd = NULL;
1419 return -ENOMEM;
1420 }
1421
1422 return 0;
1423}
1424
1425int is_tracing_stopped(void)
1426{
1427 return global_trace.stop_count;
1428}
1429
1430/**
1431 * tracing_start - quick start of the tracer
1432 *
1433 * If tracing is enabled but was stopped by tracing_stop,
1434 * this will start the tracer back up.
1435 */
1436void tracing_start(void)
1437{
1438 struct ring_buffer *buffer;
1439 unsigned long flags;
1440
1441 if (tracing_disabled)
1442 return;
1443
1444 raw_spin_lock_irqsave(&global_trace.start_lock, flags);
1445 if (--global_trace.stop_count) {
1446 if (global_trace.stop_count < 0) {
1447 /* Someone screwed up their debugging */
1448 WARN_ON_ONCE(1);
1449 global_trace.stop_count = 0;
1450 }
1451 goto out;
1452 }
1453
1454 /* Prevent the buffers from switching */
1455 arch_spin_lock(&global_trace.max_lock);
1456
1457 buffer = global_trace.trace_buffer.buffer;
1458 if (buffer)
1459 ring_buffer_record_enable(buffer);
1460
1461#ifdef CONFIG_TRACER_MAX_TRACE
1462 buffer = global_trace.max_buffer.buffer;
1463 if (buffer)
1464 ring_buffer_record_enable(buffer);
1465#endif
1466
1467 arch_spin_unlock(&global_trace.max_lock);
1468
1469 out:
1470 raw_spin_unlock_irqrestore(&global_trace.start_lock, flags);
1471}
1472
1473static void tracing_start_tr(struct trace_array *tr)
1474{
1475 struct ring_buffer *buffer;
1476 unsigned long flags;
1477
1478 if (tracing_disabled)
1479 return;
1480
1481 /* If global, we need to also start the max tracer */
1482 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
1483 return tracing_start();
1484
1485 raw_spin_lock_irqsave(&tr->start_lock, flags);
1486
1487 if (--tr->stop_count) {
1488 if (tr->stop_count < 0) {
1489 /* Someone screwed up their debugging */
1490 WARN_ON_ONCE(1);
1491 tr->stop_count = 0;
1492 }
1493 goto out;
1494 }
1495
1496 buffer = tr->trace_buffer.buffer;
1497 if (buffer)
1498 ring_buffer_record_enable(buffer);
1499
1500 out:
1501 raw_spin_unlock_irqrestore(&tr->start_lock, flags);
1502}
1503
1504/**
1505 * tracing_stop - quick stop of the tracer
1506 *
1507 * Light weight way to stop tracing. Use in conjunction with
1508 * tracing_start.
1509 */
1510void tracing_stop(void)
1511{
1512 struct ring_buffer *buffer;
1513 unsigned long flags;
1514
1515 raw_spin_lock_irqsave(&global_trace.start_lock, flags);
1516 if (global_trace.stop_count++)
1517 goto out;
1518
1519 /* Prevent the buffers from switching */
1520 arch_spin_lock(&global_trace.max_lock);
1521
1522 buffer = global_trace.trace_buffer.buffer;
1523 if (buffer)
1524 ring_buffer_record_disable(buffer);
1525
1526#ifdef CONFIG_TRACER_MAX_TRACE
1527 buffer = global_trace.max_buffer.buffer;
1528 if (buffer)
1529 ring_buffer_record_disable(buffer);
1530#endif
1531
1532 arch_spin_unlock(&global_trace.max_lock);
1533
1534 out:
1535 raw_spin_unlock_irqrestore(&global_trace.start_lock, flags);
1536}
1537
1538static void tracing_stop_tr(struct trace_array *tr)
1539{
1540 struct ring_buffer *buffer;
1541 unsigned long flags;
1542
1543 /* If global, we need to also stop the max tracer */
1544 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
1545 return tracing_stop();
1546
1547 raw_spin_lock_irqsave(&tr->start_lock, flags);
1548 if (tr->stop_count++)
1549 goto out;
1550
1551 buffer = tr->trace_buffer.buffer;
1552 if (buffer)
1553 ring_buffer_record_disable(buffer);
1554
1555 out:
1556 raw_spin_unlock_irqrestore(&tr->start_lock, flags);
1557}
1558
1559void trace_stop_cmdline_recording(void);
1560
1561static int trace_save_cmdline(struct task_struct *tsk)
1562{
1563 unsigned pid, idx;
1564
1565 if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT))
1566 return 0;
1567
1568 /*
1569 * It's not the end of the world if we don't get
1570 * the lock, but we also don't want to spin
1571 * nor do we want to disable interrupts,
1572 * so if we miss here, then better luck next time.
1573 */
1574 if (!arch_spin_trylock(&trace_cmdline_lock))
1575 return 0;
1576
1577 idx = savedcmd->map_pid_to_cmdline[tsk->pid];
1578 if (idx == NO_CMDLINE_MAP) {
1579 idx = (savedcmd->cmdline_idx + 1) % savedcmd->cmdline_num;
1580
1581 /*
1582 * Check whether the cmdline buffer at idx has a pid
1583 * mapped. We are going to overwrite that entry so we
1584 * need to clear the map_pid_to_cmdline. Otherwise we
1585 * would read the new comm for the old pid.
1586 */
1587 pid = savedcmd->map_cmdline_to_pid[idx];
1588 if (pid != NO_CMDLINE_MAP)
1589 savedcmd->map_pid_to_cmdline[pid] = NO_CMDLINE_MAP;
1590
1591 savedcmd->map_cmdline_to_pid[idx] = tsk->pid;
1592 savedcmd->map_pid_to_cmdline[tsk->pid] = idx;
1593
1594 savedcmd->cmdline_idx = idx;
1595 }
1596
1597 set_cmdline(idx, tsk->comm);
1598
1599 arch_spin_unlock(&trace_cmdline_lock);
1600
1601 return 1;
1602}
1603
1604static void __trace_find_cmdline(int pid, char comm[])
1605{
1606 unsigned map;
1607
1608 if (!pid) {
1609 strcpy(comm, "<idle>");
1610 return;
1611 }
1612
1613 if (WARN_ON_ONCE(pid < 0)) {
1614 strcpy(comm, "<XXX>");
1615 return;
1616 }
1617
1618 if (pid > PID_MAX_DEFAULT) {
1619 strcpy(comm, "<...>");
1620 return;
1621 }
1622
1623 map = savedcmd->map_pid_to_cmdline[pid];
1624 if (map != NO_CMDLINE_MAP)
1625 strcpy(comm, get_saved_cmdlines(map));
1626 else
1627 strcpy(comm, "<...>");
1628}
1629
1630void trace_find_cmdline(int pid, char comm[])
1631{
1632 preempt_disable();
1633 arch_spin_lock(&trace_cmdline_lock);
1634
1635 __trace_find_cmdline(pid, comm);
1636
1637 arch_spin_unlock(&trace_cmdline_lock);
1638 preempt_enable();
1639}
1640
1641void tracing_record_cmdline(struct task_struct *tsk)
1642{
1643 if (atomic_read(&trace_record_cmdline_disabled) || !tracing_is_on())
1644 return;
1645
1646 if (!__this_cpu_read(trace_cmdline_save))
1647 return;
1648
1649 if (trace_save_cmdline(tsk))
1650 __this_cpu_write(trace_cmdline_save, false);
1651}
1652
1653void
1654tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
1655 int pc)
1656{
1657 struct task_struct *tsk = current;
1658
1659 entry->preempt_count = pc & 0xff;
1660 entry->pid = (tsk) ? tsk->pid : 0;
1661 entry->flags =
1662#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
1663 (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
1664#else
1665 TRACE_FLAG_IRQS_NOSUPPORT |
1666#endif
1667 ((pc & NMI_MASK ) ? TRACE_FLAG_NMI : 0) |
1668 ((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
1669 ((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
1670 (tif_need_resched() ? TRACE_FLAG_NEED_RESCHED : 0) |
1671 (test_preempt_need_resched() ? TRACE_FLAG_PREEMPT_RESCHED : 0);
1672}
1673EXPORT_SYMBOL_GPL(tracing_generic_entry_update);
1674
1675struct ring_buffer_event *
1676trace_buffer_lock_reserve(struct ring_buffer *buffer,
1677 int type,
1678 unsigned long len,
1679 unsigned long flags, int pc)
1680{
1681 struct ring_buffer_event *event;
1682
1683 event = ring_buffer_lock_reserve(buffer, len);
1684 if (event != NULL) {
1685 struct trace_entry *ent = ring_buffer_event_data(event);
1686
1687 tracing_generic_entry_update(ent, flags, pc);
1688 ent->type = type;
1689 }
1690
1691 return event;
1692}
1693
1694void
1695__buffer_unlock_commit(struct ring_buffer *buffer, struct ring_buffer_event *event)
1696{
1697 __this_cpu_write(trace_cmdline_save, true);
1698 ring_buffer_unlock_commit(buffer, event);
1699}
1700
1701void trace_buffer_unlock_commit(struct trace_array *tr,
1702 struct ring_buffer *buffer,
1703 struct ring_buffer_event *event,
1704 unsigned long flags, int pc)
1705{
1706 __buffer_unlock_commit(buffer, event);
1707
1708 ftrace_trace_stack(tr, buffer, flags, 6, pc, NULL);
1709 ftrace_trace_userstack(buffer, flags, pc);
1710}
1711EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit);
1712
1713static struct ring_buffer *temp_buffer;
1714
1715struct ring_buffer_event *
1716trace_event_buffer_lock_reserve(struct ring_buffer **current_rb,
1717 struct trace_event_file *trace_file,
1718 int type, unsigned long len,
1719 unsigned long flags, int pc)
1720{
1721 struct ring_buffer_event *entry;
1722
1723 *current_rb = trace_file->tr->trace_buffer.buffer;
1724 entry = trace_buffer_lock_reserve(*current_rb,
1725 type, len, flags, pc);
1726 /*
1727 * If tracing is off, but we have triggers enabled
1728 * we still need to look at the event data. Use the temp_buffer
1729 * to store the trace event for the tigger to use. It's recusive
1730 * safe and will not be recorded anywhere.
1731 */
1732 if (!entry && trace_file->flags & EVENT_FILE_FL_TRIGGER_COND) {
1733 *current_rb = temp_buffer;
1734 entry = trace_buffer_lock_reserve(*current_rb,
1735 type, len, flags, pc);
1736 }
1737 return entry;
1738}
1739EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve);
1740
1741struct ring_buffer_event *
1742trace_current_buffer_lock_reserve(struct ring_buffer **current_rb,
1743 int type, unsigned long len,
1744 unsigned long flags, int pc)
1745{
1746 *current_rb = global_trace.trace_buffer.buffer;
1747 return trace_buffer_lock_reserve(*current_rb,
1748 type, len, flags, pc);
1749}
1750EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve);
1751
1752void trace_buffer_unlock_commit_regs(struct trace_array *tr,
1753 struct ring_buffer *buffer,
1754 struct ring_buffer_event *event,
1755 unsigned long flags, int pc,
1756 struct pt_regs *regs)
1757{
1758 __buffer_unlock_commit(buffer, event);
1759
1760 ftrace_trace_stack(tr, buffer, flags, 0, pc, regs);
1761 ftrace_trace_userstack(buffer, flags, pc);
1762}
1763EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit_regs);
1764
1765void trace_current_buffer_discard_commit(struct ring_buffer *buffer,
1766 struct ring_buffer_event *event)
1767{
1768 ring_buffer_discard_commit(buffer, event);
1769}
1770EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit);
1771
1772void
1773trace_function(struct trace_array *tr,
1774 unsigned long ip, unsigned long parent_ip, unsigned long flags,
1775 int pc)
1776{
1777 struct trace_event_call *call = &event_function;
1778 struct ring_buffer *buffer = tr->trace_buffer.buffer;
1779 struct ring_buffer_event *event;
1780 struct ftrace_entry *entry;
1781
1782 event = trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
1783 flags, pc);
1784 if (!event)
1785 return;
1786 entry = ring_buffer_event_data(event);
1787 entry->ip = ip;
1788 entry->parent_ip = parent_ip;
1789
1790 if (!call_filter_check_discard(call, entry, buffer, event))
1791 __buffer_unlock_commit(buffer, event);
1792}
1793
1794#ifdef CONFIG_STACKTRACE
1795
1796#define FTRACE_STACK_MAX_ENTRIES (PAGE_SIZE / sizeof(unsigned long))
1797struct ftrace_stack {
1798 unsigned long calls[FTRACE_STACK_MAX_ENTRIES];
1799};
1800
1801static DEFINE_PER_CPU(struct ftrace_stack, ftrace_stack);
1802static DEFINE_PER_CPU(int, ftrace_stack_reserve);
1803
1804static void __ftrace_trace_stack(struct ring_buffer *buffer,
1805 unsigned long flags,
1806 int skip, int pc, struct pt_regs *regs)
1807{
1808 struct trace_event_call *call = &event_kernel_stack;
1809 struct ring_buffer_event *event;
1810 struct stack_entry *entry;
1811 struct stack_trace trace;
1812 int use_stack;
1813 int size = FTRACE_STACK_ENTRIES;
1814
1815 trace.nr_entries = 0;
1816 trace.skip = skip;
1817
1818 /*
1819 * Since events can happen in NMIs there's no safe way to
1820 * use the per cpu ftrace_stacks. We reserve it and if an interrupt
1821 * or NMI comes in, it will just have to use the default
1822 * FTRACE_STACK_SIZE.
1823 */
1824 preempt_disable_notrace();
1825
1826 use_stack = __this_cpu_inc_return(ftrace_stack_reserve);
1827 /*
1828 * We don't need any atomic variables, just a barrier.
1829 * If an interrupt comes in, we don't care, because it would
1830 * have exited and put the counter back to what we want.
1831 * We just need a barrier to keep gcc from moving things
1832 * around.
1833 */
1834 barrier();
1835 if (use_stack == 1) {
1836 trace.entries = this_cpu_ptr(ftrace_stack.calls);
1837 trace.max_entries = FTRACE_STACK_MAX_ENTRIES;
1838
1839 if (regs)
1840 save_stack_trace_regs(regs, &trace);
1841 else
1842 save_stack_trace(&trace);
1843
1844 if (trace.nr_entries > size)
1845 size = trace.nr_entries;
1846 } else
1847 /* From now on, use_stack is a boolean */
1848 use_stack = 0;
1849
1850 size *= sizeof(unsigned long);
1851
1852 event = trace_buffer_lock_reserve(buffer, TRACE_STACK,
1853 sizeof(*entry) + size, flags, pc);
1854 if (!event)
1855 goto out;
1856 entry = ring_buffer_event_data(event);
1857
1858 memset(&entry->caller, 0, size);
1859
1860 if (use_stack)
1861 memcpy(&entry->caller, trace.entries,
1862 trace.nr_entries * sizeof(unsigned long));
1863 else {
1864 trace.max_entries = FTRACE_STACK_ENTRIES;
1865 trace.entries = entry->caller;
1866 if (regs)
1867 save_stack_trace_regs(regs, &trace);
1868 else
1869 save_stack_trace(&trace);
1870 }
1871
1872 entry->size = trace.nr_entries;
1873
1874 if (!call_filter_check_discard(call, entry, buffer, event))
1875 __buffer_unlock_commit(buffer, event);
1876
1877 out:
1878 /* Again, don't let gcc optimize things here */
1879 barrier();
1880 __this_cpu_dec(ftrace_stack_reserve);
1881 preempt_enable_notrace();
1882
1883}
1884
1885static inline void ftrace_trace_stack(struct trace_array *tr,
1886 struct ring_buffer *buffer,
1887 unsigned long flags,
1888 int skip, int pc, struct pt_regs *regs)
1889{
1890 if (!(tr->trace_flags & TRACE_ITER_STACKTRACE))
1891 return;
1892
1893 __ftrace_trace_stack(buffer, flags, skip, pc, regs);
1894}
1895
1896void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
1897 int pc)
1898{
1899 __ftrace_trace_stack(tr->trace_buffer.buffer, flags, skip, pc, NULL);
1900}
1901
1902/**
1903 * trace_dump_stack - record a stack back trace in the trace buffer
1904 * @skip: Number of functions to skip (helper handlers)
1905 */
1906void trace_dump_stack(int skip)
1907{
1908 unsigned long flags;
1909
1910 if (tracing_disabled || tracing_selftest_running)
1911 return;
1912
1913 local_save_flags(flags);
1914
1915 /*
1916 * Skip 3 more, seems to get us at the caller of
1917 * this function.
1918 */
1919 skip += 3;
1920 __ftrace_trace_stack(global_trace.trace_buffer.buffer,
1921 flags, skip, preempt_count(), NULL);
1922}
1923
1924static DEFINE_PER_CPU(int, user_stack_count);
1925
1926void
1927ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
1928{
1929 struct trace_event_call *call = &event_user_stack;
1930 struct ring_buffer_event *event;
1931 struct userstack_entry *entry;
1932 struct stack_trace trace;
1933
1934 if (!(global_trace.trace_flags & TRACE_ITER_USERSTACKTRACE))
1935 return;
1936
1937 /*
1938 * NMIs can not handle page faults, even with fix ups.
1939 * The save user stack can (and often does) fault.
1940 */
1941 if (unlikely(in_nmi()))
1942 return;
1943
1944 /*
1945 * prevent recursion, since the user stack tracing may
1946 * trigger other kernel events.
1947 */
1948 preempt_disable();
1949 if (__this_cpu_read(user_stack_count))
1950 goto out;
1951
1952 __this_cpu_inc(user_stack_count);
1953
1954 event = trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
1955 sizeof(*entry), flags, pc);
1956 if (!event)
1957 goto out_drop_count;
1958 entry = ring_buffer_event_data(event);
1959
1960 entry->tgid = current->tgid;
1961 memset(&entry->caller, 0, sizeof(entry->caller));
1962
1963 trace.nr_entries = 0;
1964 trace.max_entries = FTRACE_STACK_ENTRIES;
1965 trace.skip = 0;
1966 trace.entries = entry->caller;
1967
1968 save_stack_trace_user(&trace);
1969 if (!call_filter_check_discard(call, entry, buffer, event))
1970 __buffer_unlock_commit(buffer, event);
1971
1972 out_drop_count:
1973 __this_cpu_dec(user_stack_count);
1974 out:
1975 preempt_enable();
1976}
1977
1978#ifdef UNUSED
1979static void __trace_userstack(struct trace_array *tr, unsigned long flags)
1980{
1981 ftrace_trace_userstack(tr, flags, preempt_count());
1982}
1983#endif /* UNUSED */
1984
1985#endif /* CONFIG_STACKTRACE */
1986
1987/* created for use with alloc_percpu */
1988struct trace_buffer_struct {
1989 char buffer[TRACE_BUF_SIZE];
1990};
1991
1992static struct trace_buffer_struct *trace_percpu_buffer;
1993static struct trace_buffer_struct *trace_percpu_sirq_buffer;
1994static struct trace_buffer_struct *trace_percpu_irq_buffer;
1995static struct trace_buffer_struct *trace_percpu_nmi_buffer;
1996
1997/*
1998 * The buffer used is dependent on the context. There is a per cpu
1999 * buffer for normal context, softirq contex, hard irq context and
2000 * for NMI context. Thise allows for lockless recording.
2001 *
2002 * Note, if the buffers failed to be allocated, then this returns NULL
2003 */
2004static char *get_trace_buf(void)
2005{
2006 struct trace_buffer_struct *percpu_buffer;
2007
2008 /*
2009 * If we have allocated per cpu buffers, then we do not
2010 * need to do any locking.
2011 */
2012 if (in_nmi())
2013 percpu_buffer = trace_percpu_nmi_buffer;
2014 else if (in_irq())
2015 percpu_buffer = trace_percpu_irq_buffer;
2016 else if (in_softirq())
2017 percpu_buffer = trace_percpu_sirq_buffer;
2018 else
2019 percpu_buffer = trace_percpu_buffer;
2020
2021 if (!percpu_buffer)
2022 return NULL;
2023
2024 return this_cpu_ptr(&percpu_buffer->buffer[0]);
2025}
2026
2027static int alloc_percpu_trace_buffer(void)
2028{
2029 struct trace_buffer_struct *buffers;
2030 struct trace_buffer_struct *sirq_buffers;
2031 struct trace_buffer_struct *irq_buffers;
2032 struct trace_buffer_struct *nmi_buffers;
2033
2034 buffers = alloc_percpu(struct trace_buffer_struct);
2035 if (!buffers)
2036 goto err_warn;
2037
2038 sirq_buffers = alloc_percpu(struct trace_buffer_struct);
2039 if (!sirq_buffers)
2040 goto err_sirq;
2041
2042 irq_buffers = alloc_percpu(struct trace_buffer_struct);
2043 if (!irq_buffers)
2044 goto err_irq;
2045
2046 nmi_buffers = alloc_percpu(struct trace_buffer_struct);
2047 if (!nmi_buffers)
2048 goto err_nmi;
2049
2050 trace_percpu_buffer = buffers;
2051 trace_percpu_sirq_buffer = sirq_buffers;
2052 trace_percpu_irq_buffer = irq_buffers;
2053 trace_percpu_nmi_buffer = nmi_buffers;
2054
2055 return 0;
2056
2057 err_nmi:
2058 free_percpu(irq_buffers);
2059 err_irq:
2060 free_percpu(sirq_buffers);
2061 err_sirq:
2062 free_percpu(buffers);
2063 err_warn:
2064 WARN(1, "Could not allocate percpu trace_printk buffer");
2065 return -ENOMEM;
2066}
2067
2068static int buffers_allocated;
2069
2070void trace_printk_init_buffers(void)
2071{
2072 if (buffers_allocated)
2073 return;
2074
2075 if (alloc_percpu_trace_buffer())
2076 return;
2077
2078 /* trace_printk() is for debug use only. Don't use it in production. */
2079
2080 pr_warn("\n");
2081 pr_warn("**********************************************************\n");
2082 pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
2083 pr_warn("** **\n");
2084 pr_warn("** trace_printk() being used. Allocating extra memory. **\n");
2085 pr_warn("** **\n");
2086 pr_warn("** This means that this is a DEBUG kernel and it is **\n");
2087 pr_warn("** unsafe for production use. **\n");
2088 pr_warn("** **\n");
2089 pr_warn("** If you see this message and you are not debugging **\n");
2090 pr_warn("** the kernel, report this immediately to your vendor! **\n");
2091 pr_warn("** **\n");
2092 pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
2093 pr_warn("**********************************************************\n");
2094
2095 /* Expand the buffers to set size */
2096 tracing_update_buffers();
2097
2098 buffers_allocated = 1;
2099
2100 /*
2101 * trace_printk_init_buffers() can be called by modules.
2102 * If that happens, then we need to start cmdline recording
2103 * directly here. If the global_trace.buffer is already
2104 * allocated here, then this was called by module code.
2105 */
2106 if (global_trace.trace_buffer.buffer)
2107 tracing_start_cmdline_record();
2108}
2109
2110void trace_printk_start_comm(void)
2111{
2112 /* Start tracing comms if trace printk is set */
2113 if (!buffers_allocated)
2114 return;
2115 tracing_start_cmdline_record();
2116}
2117
2118static void trace_printk_start_stop_comm(int enabled)
2119{
2120 if (!buffers_allocated)
2121 return;
2122
2123 if (enabled)
2124 tracing_start_cmdline_record();
2125 else
2126 tracing_stop_cmdline_record();
2127}
2128
2129/**
2130 * trace_vbprintk - write binary msg to tracing buffer
2131 *
2132 */
2133int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
2134{
2135 struct trace_event_call *call = &event_bprint;
2136 struct ring_buffer_event *event;
2137 struct ring_buffer *buffer;
2138 struct trace_array *tr = &global_trace;
2139 struct bprint_entry *entry;
2140 unsigned long flags;
2141 char *tbuffer;
2142 int len = 0, size, pc;
2143
2144 if (unlikely(tracing_selftest_running || tracing_disabled))
2145 return 0;
2146
2147 /* Don't pollute graph traces with trace_vprintk internals */
2148 pause_graph_tracing();
2149
2150 pc = preempt_count();
2151 preempt_disable_notrace();
2152
2153 tbuffer = get_trace_buf();
2154 if (!tbuffer) {
2155 len = 0;
2156 goto out;
2157 }
2158
2159 len = vbin_printf((u32 *)tbuffer, TRACE_BUF_SIZE/sizeof(int), fmt, args);
2160
2161 if (len > TRACE_BUF_SIZE/sizeof(int) || len < 0)
2162 goto out;
2163
2164 local_save_flags(flags);
2165 size = sizeof(*entry) + sizeof(u32) * len;
2166 buffer = tr->trace_buffer.buffer;
2167 event = trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
2168 flags, pc);
2169 if (!event)
2170 goto out;
2171 entry = ring_buffer_event_data(event);
2172 entry->ip = ip;
2173 entry->fmt = fmt;
2174
2175 memcpy(entry->buf, tbuffer, sizeof(u32) * len);
2176 if (!call_filter_check_discard(call, entry, buffer, event)) {
2177 __buffer_unlock_commit(buffer, event);
2178 ftrace_trace_stack(tr, buffer, flags, 6, pc, NULL);
2179 }
2180
2181out:
2182 preempt_enable_notrace();
2183 unpause_graph_tracing();
2184
2185 return len;
2186}
2187EXPORT_SYMBOL_GPL(trace_vbprintk);
2188
2189static int
2190__trace_array_vprintk(struct ring_buffer *buffer,
2191 unsigned long ip, const char *fmt, va_list args)
2192{
2193 struct trace_event_call *call = &event_print;
2194 struct ring_buffer_event *event;
2195 int len = 0, size, pc;
2196 struct print_entry *entry;
2197 unsigned long flags;
2198 char *tbuffer;
2199
2200 if (tracing_disabled || tracing_selftest_running)
2201 return 0;
2202
2203 /* Don't pollute graph traces with trace_vprintk internals */
2204 pause_graph_tracing();
2205
2206 pc = preempt_count();
2207 preempt_disable_notrace();
2208
2209
2210 tbuffer = get_trace_buf();
2211 if (!tbuffer) {
2212 len = 0;
2213 goto out;
2214 }
2215
2216 len = vscnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args);
2217
2218 local_save_flags(flags);
2219 size = sizeof(*entry) + len + 1;
2220 event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
2221 flags, pc);
2222 if (!event)
2223 goto out;
2224 entry = ring_buffer_event_data(event);
2225 entry->ip = ip;
2226
2227 memcpy(&entry->buf, tbuffer, len + 1);
2228 if (!call_filter_check_discard(call, entry, buffer, event)) {
2229 __buffer_unlock_commit(buffer, event);
2230 ftrace_trace_stack(&global_trace, buffer, flags, 6, pc, NULL);
2231 }
2232 out:
2233 preempt_enable_notrace();
2234 unpause_graph_tracing();
2235
2236 return len;
2237}
2238
2239int trace_array_vprintk(struct trace_array *tr,
2240 unsigned long ip, const char *fmt, va_list args)
2241{
2242 return __trace_array_vprintk(tr->trace_buffer.buffer, ip, fmt, args);
2243}
2244
2245int trace_array_printk(struct trace_array *tr,
2246 unsigned long ip, const char *fmt, ...)
2247{
2248 int ret;
2249 va_list ap;
2250
2251 if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
2252 return 0;
2253
2254 va_start(ap, fmt);
2255 ret = trace_array_vprintk(tr, ip, fmt, ap);
2256 va_end(ap);
2257 return ret;
2258}
2259
2260int trace_array_printk_buf(struct ring_buffer *buffer,
2261 unsigned long ip, const char *fmt, ...)
2262{
2263 int ret;
2264 va_list ap;
2265
2266 if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
2267 return 0;
2268
2269 va_start(ap, fmt);
2270 ret = __trace_array_vprintk(buffer, ip, fmt, ap);
2271 va_end(ap);
2272 return ret;
2273}
2274
2275int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
2276{
2277 return trace_array_vprintk(&global_trace, ip, fmt, args);
2278}
2279EXPORT_SYMBOL_GPL(trace_vprintk);
2280
2281static void trace_iterator_increment(struct trace_iterator *iter)
2282{
2283 struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, iter->cpu);
2284
2285 iter->idx++;
2286 if (buf_iter)
2287 ring_buffer_read(buf_iter, NULL);
2288}
2289
2290static struct trace_entry *
2291peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts,
2292 unsigned long *lost_events)
2293{
2294 struct ring_buffer_event *event;
2295 struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, cpu);
2296
2297 if (buf_iter)
2298 event = ring_buffer_iter_peek(buf_iter, ts);
2299 else
2300 event = ring_buffer_peek(iter->trace_buffer->buffer, cpu, ts,
2301 lost_events);
2302
2303 if (event) {
2304 iter->ent_size = ring_buffer_event_length(event);
2305 return ring_buffer_event_data(event);
2306 }
2307 iter->ent_size = 0;
2308 return NULL;
2309}
2310
2311static struct trace_entry *
2312__find_next_entry(struct trace_iterator *iter, int *ent_cpu,
2313 unsigned long *missing_events, u64 *ent_ts)
2314{
2315 struct ring_buffer *buffer = iter->trace_buffer->buffer;
2316 struct trace_entry *ent, *next = NULL;
2317 unsigned long lost_events = 0, next_lost = 0;
2318 int cpu_file = iter->cpu_file;
2319 u64 next_ts = 0, ts;
2320 int next_cpu = -1;
2321 int next_size = 0;
2322 int cpu;
2323
2324 /*
2325 * If we are in a per_cpu trace file, don't bother by iterating over
2326 * all cpu and peek directly.
2327 */
2328 if (cpu_file > RING_BUFFER_ALL_CPUS) {
2329 if (ring_buffer_empty_cpu(buffer, cpu_file))
2330 return NULL;
2331 ent = peek_next_entry(iter, cpu_file, ent_ts, missing_events);
2332 if (ent_cpu)
2333 *ent_cpu = cpu_file;
2334
2335 return ent;
2336 }
2337
2338 for_each_tracing_cpu(cpu) {
2339
2340 if (ring_buffer_empty_cpu(buffer, cpu))
2341 continue;
2342
2343 ent = peek_next_entry(iter, cpu, &ts, &lost_events);
2344
2345 /*
2346 * Pick the entry with the smallest timestamp:
2347 */
2348 if (ent && (!next || ts < next_ts)) {
2349 next = ent;
2350 next_cpu = cpu;
2351 next_ts = ts;
2352 next_lost = lost_events;
2353 next_size = iter->ent_size;
2354 }
2355 }
2356
2357 iter->ent_size = next_size;
2358
2359 if (ent_cpu)
2360 *ent_cpu = next_cpu;
2361
2362 if (ent_ts)
2363 *ent_ts = next_ts;
2364
2365 if (missing_events)
2366 *missing_events = next_lost;
2367
2368 return next;
2369}
2370
2371/* Find the next real entry, without updating the iterator itself */
2372struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
2373 int *ent_cpu, u64 *ent_ts)
2374{
2375 return __find_next_entry(iter, ent_cpu, NULL, ent_ts);
2376}
2377
2378/* Find the next real entry, and increment the iterator to the next entry */
2379void *trace_find_next_entry_inc(struct trace_iterator *iter)
2380{
2381 iter->ent = __find_next_entry(iter, &iter->cpu,
2382 &iter->lost_events, &iter->ts);
2383
2384 if (iter->ent)
2385 trace_iterator_increment(iter);
2386
2387 return iter->ent ? iter : NULL;
2388}
2389
2390static void trace_consume(struct trace_iterator *iter)
2391{
2392 ring_buffer_consume(iter->trace_buffer->buffer, iter->cpu, &iter->ts,
2393 &iter->lost_events);
2394}
2395
2396static void *s_next(struct seq_file *m, void *v, loff_t *pos)
2397{
2398 struct trace_iterator *iter = m->private;
2399 int i = (int)*pos;
2400 void *ent;
2401
2402 WARN_ON_ONCE(iter->leftover);
2403
2404 (*pos)++;
2405
2406 /* can't go backwards */
2407 if (iter->idx > i)
2408 return NULL;
2409
2410 if (iter->idx < 0)
2411 ent = trace_find_next_entry_inc(iter);
2412 else
2413 ent = iter;
2414
2415 while (ent && iter->idx < i)
2416 ent = trace_find_next_entry_inc(iter);
2417
2418 iter->pos = *pos;
2419
2420 return ent;
2421}
2422
2423void tracing_iter_reset(struct trace_iterator *iter, int cpu)
2424{
2425 struct ring_buffer_event *event;
2426 struct ring_buffer_iter *buf_iter;
2427 unsigned long entries = 0;
2428 u64 ts;
2429
2430 per_cpu_ptr(iter->trace_buffer->data, cpu)->skipped_entries = 0;
2431
2432 buf_iter = trace_buffer_iter(iter, cpu);
2433 if (!buf_iter)
2434 return;
2435
2436 ring_buffer_iter_reset(buf_iter);
2437
2438 /*
2439 * We could have the case with the max latency tracers
2440 * that a reset never took place on a cpu. This is evident
2441 * by the timestamp being before the start of the buffer.
2442 */
2443 while ((event = ring_buffer_iter_peek(buf_iter, &ts))) {
2444 if (ts >= iter->trace_buffer->time_start)
2445 break;
2446 entries++;
2447 ring_buffer_read(buf_iter, NULL);
2448 }
2449
2450 per_cpu_ptr(iter->trace_buffer->data, cpu)->skipped_entries = entries;
2451}
2452
2453/*
2454 * The current tracer is copied to avoid a global locking
2455 * all around.
2456 */
2457static void *s_start(struct seq_file *m, loff_t *pos)
2458{
2459 struct trace_iterator *iter = m->private;
2460 struct trace_array *tr = iter->tr;
2461 int cpu_file = iter->cpu_file;
2462 void *p = NULL;
2463 loff_t l = 0;
2464 int cpu;
2465
2466 /*
2467 * copy the tracer to avoid using a global lock all around.
2468 * iter->trace is a copy of current_trace, the pointer to the
2469 * name may be used instead of a strcmp(), as iter->trace->name
2470 * will point to the same string as current_trace->name.
2471 */
2472 mutex_lock(&trace_types_lock);
2473 if (unlikely(tr->current_trace && iter->trace->name != tr->current_trace->name))
2474 *iter->trace = *tr->current_trace;
2475 mutex_unlock(&trace_types_lock);
2476
2477#ifdef CONFIG_TRACER_MAX_TRACE
2478 if (iter->snapshot && iter->trace->use_max_tr)
2479 return ERR_PTR(-EBUSY);
2480#endif
2481
2482 if (!iter->snapshot)
2483 atomic_inc(&trace_record_cmdline_disabled);
2484
2485 if (*pos != iter->pos) {
2486 iter->ent = NULL;
2487 iter->cpu = 0;
2488 iter->idx = -1;
2489
2490 if (cpu_file == RING_BUFFER_ALL_CPUS) {
2491 for_each_tracing_cpu(cpu)
2492 tracing_iter_reset(iter, cpu);
2493 } else
2494 tracing_iter_reset(iter, cpu_file);
2495
2496 iter->leftover = 0;
2497 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
2498 ;
2499
2500 } else {
2501 /*
2502 * If we overflowed the seq_file before, then we want
2503 * to just reuse the trace_seq buffer again.
2504 */
2505 if (iter->leftover)
2506 p = iter;
2507 else {
2508 l = *pos - 1;
2509 p = s_next(m, p, &l);
2510 }
2511 }
2512
2513 trace_event_read_lock();
2514 trace_access_lock(cpu_file);
2515 return p;
2516}
2517
2518static void s_stop(struct seq_file *m, void *p)
2519{
2520 struct trace_iterator *iter = m->private;
2521
2522#ifdef CONFIG_TRACER_MAX_TRACE
2523 if (iter->snapshot && iter->trace->use_max_tr)
2524 return;
2525#endif
2526
2527 if (!iter->snapshot)
2528 atomic_dec(&trace_record_cmdline_disabled);
2529
2530 trace_access_unlock(iter->cpu_file);
2531 trace_event_read_unlock();
2532}
2533
2534static void
2535get_total_entries(struct trace_buffer *buf,
2536 unsigned long *total, unsigned long *entries)
2537{
2538 unsigned long count;
2539 int cpu;
2540
2541 *total = 0;
2542 *entries = 0;
2543
2544 for_each_tracing_cpu(cpu) {
2545 count = ring_buffer_entries_cpu(buf->buffer, cpu);
2546 /*
2547 * If this buffer has skipped entries, then we hold all
2548 * entries for the trace and we need to ignore the
2549 * ones before the time stamp.
2550 */
2551 if (per_cpu_ptr(buf->data, cpu)->skipped_entries) {
2552 count -= per_cpu_ptr(buf->data, cpu)->skipped_entries;
2553 /* total is the same as the entries */
2554 *total += count;
2555 } else
2556 *total += count +
2557 ring_buffer_overrun_cpu(buf->buffer, cpu);
2558 *entries += count;
2559 }
2560}
2561
2562static void print_lat_help_header(struct seq_file *m)
2563{
2564 seq_puts(m, "# _------=> CPU# \n"
2565 "# / _-----=> irqs-off \n"
2566 "# | / _----=> need-resched \n"
2567 "# || / _---=> hardirq/softirq \n"
2568 "# ||| / _--=> preempt-depth \n"
2569 "# |||| / delay \n"
2570 "# cmd pid ||||| time | caller \n"
2571 "# \\ / ||||| \\ | / \n");
2572}
2573
2574static void print_event_info(struct trace_buffer *buf, struct seq_file *m)
2575{
2576 unsigned long total;
2577 unsigned long entries;
2578
2579 get_total_entries(buf, &total, &entries);
2580 seq_printf(m, "# entries-in-buffer/entries-written: %lu/%lu #P:%d\n",
2581 entries, total, num_online_cpus());
2582 seq_puts(m, "#\n");
2583}
2584
2585static void print_func_help_header(struct trace_buffer *buf, struct seq_file *m)
2586{
2587 print_event_info(buf, m);
2588 seq_puts(m, "# TASK-PID CPU# TIMESTAMP FUNCTION\n"
2589 "# | | | | |\n");
2590}
2591
2592static void print_func_help_header_irq(struct trace_buffer *buf, struct seq_file *m)
2593{
2594 print_event_info(buf, m);
2595 seq_puts(m, "# _-----=> irqs-off\n"
2596 "# / _----=> need-resched\n"
2597 "# | / _---=> hardirq/softirq\n"
2598 "# || / _--=> preempt-depth\n"
2599 "# ||| / delay\n"
2600 "# TASK-PID CPU# |||| TIMESTAMP FUNCTION\n"
2601 "# | | | |||| | |\n");
2602}
2603
2604void
2605print_trace_header(struct seq_file *m, struct trace_iterator *iter)
2606{
2607 unsigned long sym_flags = (global_trace.trace_flags & TRACE_ITER_SYM_MASK);
2608 struct trace_buffer *buf = iter->trace_buffer;
2609 struct trace_array_cpu *data = per_cpu_ptr(buf->data, buf->cpu);
2610 struct tracer *type = iter->trace;
2611 unsigned long entries;
2612 unsigned long total;
2613 const char *name = "preemption";
2614
2615 name = type->name;
2616
2617 get_total_entries(buf, &total, &entries);
2618
2619 seq_printf(m, "# %s latency trace v1.1.5 on %s\n",
2620 name, UTS_RELEASE);
2621 seq_puts(m, "# -----------------------------------"
2622 "---------------------------------\n");
2623 seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d |"
2624 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
2625 nsecs_to_usecs(data->saved_latency),
2626 entries,
2627 total,
2628 buf->cpu,
2629#if defined(CONFIG_PREEMPT_NONE)
2630 "server",
2631#elif defined(CONFIG_PREEMPT_VOLUNTARY)
2632 "desktop",
2633#elif defined(CONFIG_PREEMPT)
2634 "preempt",
2635#else
2636 "unknown",
2637#endif
2638 /* These are reserved for later use */
2639 0, 0, 0, 0);
2640#ifdef CONFIG_SMP
2641 seq_printf(m, " #P:%d)\n", num_online_cpus());
2642#else
2643 seq_puts(m, ")\n");
2644#endif
2645 seq_puts(m, "# -----------------\n");
2646 seq_printf(m, "# | task: %.16s-%d "
2647 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
2648 data->comm, data->pid,
2649 from_kuid_munged(seq_user_ns(m), data->uid), data->nice,
2650 data->policy, data->rt_priority);
2651 seq_puts(m, "# -----------------\n");
2652
2653 if (data->critical_start) {
2654 seq_puts(m, "# => started at: ");
2655 seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
2656 trace_print_seq(m, &iter->seq);
2657 seq_puts(m, "\n# => ended at: ");
2658 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
2659 trace_print_seq(m, &iter->seq);
2660 seq_puts(m, "\n#\n");
2661 }
2662
2663 seq_puts(m, "#\n");
2664}
2665
2666static void test_cpu_buff_start(struct trace_iterator *iter)
2667{
2668 struct trace_seq *s = &iter->seq;
2669 struct trace_array *tr = iter->tr;
2670
2671 if (!(tr->trace_flags & TRACE_ITER_ANNOTATE))
2672 return;
2673
2674 if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
2675 return;
2676
2677 if (iter->started && cpumask_test_cpu(iter->cpu, iter->started))
2678 return;
2679
2680 if (per_cpu_ptr(iter->trace_buffer->data, iter->cpu)->skipped_entries)
2681 return;
2682
2683 if (iter->started)
2684 cpumask_set_cpu(iter->cpu, iter->started);
2685
2686 /* Don't print started cpu buffer for the first entry of the trace */
2687 if (iter->idx > 1)
2688 trace_seq_printf(s, "##### CPU %u buffer started ####\n",
2689 iter->cpu);
2690}
2691
2692static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
2693{
2694 struct trace_array *tr = iter->tr;
2695 struct trace_seq *s = &iter->seq;
2696 unsigned long sym_flags = (tr->trace_flags & TRACE_ITER_SYM_MASK);
2697 struct trace_entry *entry;
2698 struct trace_event *event;
2699
2700 entry = iter->ent;
2701
2702 test_cpu_buff_start(iter);
2703
2704 event = ftrace_find_event(entry->type);
2705
2706 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
2707 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
2708 trace_print_lat_context(iter);
2709 else
2710 trace_print_context(iter);
2711 }
2712
2713 if (trace_seq_has_overflowed(s))
2714 return TRACE_TYPE_PARTIAL_LINE;
2715
2716 if (event)
2717 return event->funcs->trace(iter, sym_flags, event);
2718
2719 trace_seq_printf(s, "Unknown type %d\n", entry->type);
2720
2721 return trace_handle_return(s);
2722}
2723
2724static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
2725{
2726 struct trace_array *tr = iter->tr;
2727 struct trace_seq *s = &iter->seq;
2728 struct trace_entry *entry;
2729 struct trace_event *event;
2730
2731 entry = iter->ent;
2732
2733 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO)
2734 trace_seq_printf(s, "%d %d %llu ",
2735 entry->pid, iter->cpu, iter->ts);
2736
2737 if (trace_seq_has_overflowed(s))
2738 return TRACE_TYPE_PARTIAL_LINE;
2739
2740 event = ftrace_find_event(entry->type);
2741 if (event)
2742 return event->funcs->raw(iter, 0, event);
2743
2744 trace_seq_printf(s, "%d ?\n", entry->type);
2745
2746 return trace_handle_return(s);
2747}
2748
2749static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
2750{
2751 struct trace_array *tr = iter->tr;
2752 struct trace_seq *s = &iter->seq;
2753 unsigned char newline = '\n';
2754 struct trace_entry *entry;
2755 struct trace_event *event;
2756
2757 entry = iter->ent;
2758
2759 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
2760 SEQ_PUT_HEX_FIELD(s, entry->pid);
2761 SEQ_PUT_HEX_FIELD(s, iter->cpu);
2762 SEQ_PUT_HEX_FIELD(s, iter->ts);
2763 if (trace_seq_has_overflowed(s))
2764 return TRACE_TYPE_PARTIAL_LINE;
2765 }
2766
2767 event = ftrace_find_event(entry->type);
2768 if (event) {
2769 enum print_line_t ret = event->funcs->hex(iter, 0, event);
2770 if (ret != TRACE_TYPE_HANDLED)
2771 return ret;
2772 }
2773
2774 SEQ_PUT_FIELD(s, newline);
2775
2776 return trace_handle_return(s);
2777}
2778
2779static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
2780{
2781 struct trace_array *tr = iter->tr;
2782 struct trace_seq *s = &iter->seq;
2783 struct trace_entry *entry;
2784 struct trace_event *event;
2785
2786 entry = iter->ent;
2787
2788 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
2789 SEQ_PUT_FIELD(s, entry->pid);
2790 SEQ_PUT_FIELD(s, iter->cpu);
2791 SEQ_PUT_FIELD(s, iter->ts);
2792 if (trace_seq_has_overflowed(s))
2793 return TRACE_TYPE_PARTIAL_LINE;
2794 }
2795
2796 event = ftrace_find_event(entry->type);
2797 return event ? event->funcs->binary(iter, 0, event) :
2798 TRACE_TYPE_HANDLED;
2799}
2800
2801int trace_empty(struct trace_iterator *iter)
2802{
2803 struct ring_buffer_iter *buf_iter;
2804 int cpu;
2805
2806 /* If we are looking at one CPU buffer, only check that one */
2807 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
2808 cpu = iter->cpu_file;
2809 buf_iter = trace_buffer_iter(iter, cpu);
2810 if (buf_iter) {
2811 if (!ring_buffer_iter_empty(buf_iter))
2812 return 0;
2813 } else {
2814 if (!ring_buffer_empty_cpu(iter->trace_buffer->buffer, cpu))
2815 return 0;
2816 }
2817 return 1;
2818 }
2819
2820 for_each_tracing_cpu(cpu) {
2821 buf_iter = trace_buffer_iter(iter, cpu);
2822 if (buf_iter) {
2823 if (!ring_buffer_iter_empty(buf_iter))
2824 return 0;
2825 } else {
2826 if (!ring_buffer_empty_cpu(iter->trace_buffer->buffer, cpu))
2827 return 0;
2828 }
2829 }
2830
2831 return 1;
2832}
2833
2834/* Called with trace_event_read_lock() held. */
2835enum print_line_t print_trace_line(struct trace_iterator *iter)
2836{
2837 struct trace_array *tr = iter->tr;
2838 unsigned long trace_flags = tr->trace_flags;
2839 enum print_line_t ret;
2840
2841 if (iter->lost_events) {
2842 trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
2843 iter->cpu, iter->lost_events);
2844 if (trace_seq_has_overflowed(&iter->seq))
2845 return TRACE_TYPE_PARTIAL_LINE;
2846 }
2847
2848 if (iter->trace && iter->trace->print_line) {
2849 ret = iter->trace->print_line(iter);
2850 if (ret != TRACE_TYPE_UNHANDLED)
2851 return ret;
2852 }
2853
2854 if (iter->ent->type == TRACE_BPUTS &&
2855 trace_flags & TRACE_ITER_PRINTK &&
2856 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
2857 return trace_print_bputs_msg_only(iter);
2858
2859 if (iter->ent->type == TRACE_BPRINT &&
2860 trace_flags & TRACE_ITER_PRINTK &&
2861 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
2862 return trace_print_bprintk_msg_only(iter);
2863
2864 if (iter->ent->type == TRACE_PRINT &&
2865 trace_flags & TRACE_ITER_PRINTK &&
2866 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
2867 return trace_print_printk_msg_only(iter);
2868
2869 if (trace_flags & TRACE_ITER_BIN)
2870 return print_bin_fmt(iter);
2871
2872 if (trace_flags & TRACE_ITER_HEX)
2873 return print_hex_fmt(iter);
2874
2875 if (trace_flags & TRACE_ITER_RAW)
2876 return print_raw_fmt(iter);
2877
2878 return print_trace_fmt(iter);
2879}
2880
2881void trace_latency_header(struct seq_file *m)
2882{
2883 struct trace_iterator *iter = m->private;
2884 struct trace_array *tr = iter->tr;
2885
2886 /* print nothing if the buffers are empty */
2887 if (trace_empty(iter))
2888 return;
2889
2890 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
2891 print_trace_header(m, iter);
2892
2893 if (!(tr->trace_flags & TRACE_ITER_VERBOSE))
2894 print_lat_help_header(m);
2895}
2896
2897void trace_default_header(struct seq_file *m)
2898{
2899 struct trace_iterator *iter = m->private;
2900 struct trace_array *tr = iter->tr;
2901 unsigned long trace_flags = tr->trace_flags;
2902
2903 if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
2904 return;
2905
2906 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
2907 /* print nothing if the buffers are empty */
2908 if (trace_empty(iter))
2909 return;
2910 print_trace_header(m, iter);
2911 if (!(trace_flags & TRACE_ITER_VERBOSE))
2912 print_lat_help_header(m);
2913 } else {
2914 if (!(trace_flags & TRACE_ITER_VERBOSE)) {
2915 if (trace_flags & TRACE_ITER_IRQ_INFO)
2916 print_func_help_header_irq(iter->trace_buffer, m);
2917 else
2918 print_func_help_header(iter->trace_buffer, m);
2919 }
2920 }
2921}
2922
2923static void test_ftrace_alive(struct seq_file *m)
2924{
2925 if (!ftrace_is_dead())
2926 return;
2927 seq_puts(m, "# WARNING: FUNCTION TRACING IS CORRUPTED\n"
2928 "# MAY BE MISSING FUNCTION EVENTS\n");
2929}
2930
2931#ifdef CONFIG_TRACER_MAX_TRACE
2932static void show_snapshot_main_help(struct seq_file *m)
2933{
2934 seq_puts(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n"
2935 "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
2936 "# Takes a snapshot of the main buffer.\n"
2937 "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate or free)\n"
2938 "# (Doesn't have to be '2' works with any number that\n"
2939 "# is not a '0' or '1')\n");
2940}
2941
2942static void show_snapshot_percpu_help(struct seq_file *m)
2943{
2944 seq_puts(m, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n");
2945#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
2946 seq_puts(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
2947 "# Takes a snapshot of the main buffer for this cpu.\n");
2948#else
2949 seq_puts(m, "# echo 1 > snapshot : Not supported with this kernel.\n"
2950 "# Must use main snapshot file to allocate.\n");
2951#endif
2952 seq_puts(m, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n"
2953 "# (Doesn't have to be '2' works with any number that\n"
2954 "# is not a '0' or '1')\n");
2955}
2956
2957static void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter)
2958{
2959 if (iter->tr->allocated_snapshot)
2960 seq_puts(m, "#\n# * Snapshot is allocated *\n#\n");
2961 else
2962 seq_puts(m, "#\n# * Snapshot is freed *\n#\n");
2963
2964 seq_puts(m, "# Snapshot commands:\n");
2965 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
2966 show_snapshot_main_help(m);
2967 else
2968 show_snapshot_percpu_help(m);
2969}
2970#else
2971/* Should never be called */
2972static inline void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter) { }
2973#endif
2974
2975static int s_show(struct seq_file *m, void *v)
2976{
2977 struct trace_iterator *iter = v;
2978 int ret;
2979
2980 if (iter->ent == NULL) {
2981 if (iter->tr) {
2982 seq_printf(m, "# tracer: %s\n", iter->trace->name);
2983 seq_puts(m, "#\n");
2984 test_ftrace_alive(m);
2985 }
2986 if (iter->snapshot && trace_empty(iter))
2987 print_snapshot_help(m, iter);
2988 else if (iter->trace && iter->trace->print_header)
2989 iter->trace->print_header(m);
2990 else
2991 trace_default_header(m);
2992
2993 } else if (iter->leftover) {
2994 /*
2995 * If we filled the seq_file buffer earlier, we
2996 * want to just show it now.
2997 */
2998 ret = trace_print_seq(m, &iter->seq);
2999
3000 /* ret should this time be zero, but you never know */
3001 iter->leftover = ret;
3002
3003 } else {
3004 print_trace_line(iter);
3005 ret = trace_print_seq(m, &iter->seq);
3006 /*
3007 * If we overflow the seq_file buffer, then it will
3008 * ask us for this data again at start up.
3009 * Use that instead.
3010 * ret is 0 if seq_file write succeeded.
3011 * -1 otherwise.
3012 */
3013 iter->leftover = ret;
3014 }
3015
3016 return 0;
3017}
3018
3019/*
3020 * Should be used after trace_array_get(), trace_types_lock
3021 * ensures that i_cdev was already initialized.
3022 */
3023static inline int tracing_get_cpu(struct inode *inode)
3024{
3025 if (inode->i_cdev) /* See trace_create_cpu_file() */
3026 return (long)inode->i_cdev - 1;
3027 return RING_BUFFER_ALL_CPUS;
3028}
3029
3030static const struct seq_operations tracer_seq_ops = {
3031 .start = s_start,
3032 .next = s_next,
3033 .stop = s_stop,
3034 .show = s_show,
3035};
3036
3037static struct trace_iterator *
3038__tracing_open(struct inode *inode, struct file *file, bool snapshot)
3039{
3040 struct trace_array *tr = inode->i_private;
3041 struct trace_iterator *iter;
3042 int cpu;
3043
3044 if (tracing_disabled)
3045 return ERR_PTR(-ENODEV);
3046
3047 iter = __seq_open_private(file, &tracer_seq_ops, sizeof(*iter));
3048 if (!iter)
3049 return ERR_PTR(-ENOMEM);
3050
3051 iter->buffer_iter = kcalloc(nr_cpu_ids, sizeof(*iter->buffer_iter),
3052 GFP_KERNEL);
3053 if (!iter->buffer_iter)
3054 goto release;
3055
3056 /*
3057 * We make a copy of the current tracer to avoid concurrent
3058 * changes on it while we are reading.
3059 */
3060 mutex_lock(&trace_types_lock);
3061 iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL);
3062 if (!iter->trace)
3063 goto fail;
3064
3065 *iter->trace = *tr->current_trace;
3066
3067 if (!zalloc_cpumask_var(&iter->started, GFP_KERNEL))
3068 goto fail;
3069
3070 iter->tr = tr;
3071
3072#ifdef CONFIG_TRACER_MAX_TRACE
3073 /* Currently only the top directory has a snapshot */
3074 if (tr->current_trace->print_max || snapshot)
3075 iter->trace_buffer = &tr->max_buffer;
3076 else
3077#endif
3078 iter->trace_buffer = &tr->trace_buffer;
3079 iter->snapshot = snapshot;
3080 iter->pos = -1;
3081 iter->cpu_file = tracing_get_cpu(inode);
3082 mutex_init(&iter->mutex);
3083
3084 /* Notify the tracer early; before we stop tracing. */
3085 if (iter->trace && iter->trace->open)
3086 iter->trace->open(iter);
3087
3088 /* Annotate start of buffers if we had overruns */
3089 if (ring_buffer_overruns(iter->trace_buffer->buffer))
3090 iter->iter_flags |= TRACE_FILE_ANNOTATE;
3091
3092 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
3093 if (trace_clocks[tr->clock_id].in_ns)
3094 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
3095
3096 /* stop the trace while dumping if we are not opening "snapshot" */
3097 if (!iter->snapshot)
3098 tracing_stop_tr(tr);
3099
3100 if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
3101 for_each_tracing_cpu(cpu) {
3102 iter->buffer_iter[cpu] =
3103 ring_buffer_read_prepare(iter->trace_buffer->buffer, cpu);
3104 }
3105 ring_buffer_read_prepare_sync();
3106 for_each_tracing_cpu(cpu) {
3107 ring_buffer_read_start(iter->buffer_iter[cpu]);
3108 tracing_iter_reset(iter, cpu);
3109 }
3110 } else {
3111 cpu = iter->cpu_file;
3112 iter->buffer_iter[cpu] =
3113 ring_buffer_read_prepare(iter->trace_buffer->buffer, cpu);
3114 ring_buffer_read_prepare_sync();
3115 ring_buffer_read_start(iter->buffer_iter[cpu]);
3116 tracing_iter_reset(iter, cpu);
3117 }
3118
3119 mutex_unlock(&trace_types_lock);
3120
3121 return iter;
3122
3123 fail:
3124 mutex_unlock(&trace_types_lock);
3125 kfree(iter->trace);
3126 kfree(iter->buffer_iter);
3127release:
3128 seq_release_private(inode, file);
3129 return ERR_PTR(-ENOMEM);
3130}
3131
3132int tracing_open_generic(struct inode *inode, struct file *filp)
3133{
3134 if (tracing_disabled)
3135 return -ENODEV;
3136
3137 filp->private_data = inode->i_private;
3138 return 0;
3139}
3140
3141bool tracing_is_disabled(void)
3142{
3143 return (tracing_disabled) ? true: false;
3144}
3145
3146/*
3147 * Open and update trace_array ref count.
3148 * Must have the current trace_array passed to it.
3149 */
3150static int tracing_open_generic_tr(struct inode *inode, struct file *filp)
3151{
3152 struct trace_array *tr = inode->i_private;
3153
3154 if (tracing_disabled)
3155 return -ENODEV;
3156
3157 if (trace_array_get(tr) < 0)
3158 return -ENODEV;
3159
3160 filp->private_data = inode->i_private;
3161
3162 return 0;
3163}
3164
3165static int tracing_release(struct inode *inode, struct file *file)
3166{
3167 struct trace_array *tr = inode->i_private;
3168 struct seq_file *m = file->private_data;
3169 struct trace_iterator *iter;
3170 int cpu;
3171
3172 if (!(file->f_mode & FMODE_READ)) {
3173 trace_array_put(tr);
3174 return 0;
3175 }
3176
3177 /* Writes do not use seq_file */
3178 iter = m->private;
3179 mutex_lock(&trace_types_lock);
3180
3181 for_each_tracing_cpu(cpu) {
3182 if (iter->buffer_iter[cpu])
3183 ring_buffer_read_finish(iter->buffer_iter[cpu]);
3184 }
3185
3186 if (iter->trace && iter->trace->close)
3187 iter->trace->close(iter);
3188
3189 if (!iter->snapshot)
3190 /* reenable tracing if it was previously enabled */
3191 tracing_start_tr(tr);
3192
3193 __trace_array_put(tr);
3194
3195 mutex_unlock(&trace_types_lock);
3196
3197 mutex_destroy(&iter->mutex);
3198 free_cpumask_var(iter->started);
3199 kfree(iter->trace);
3200 kfree(iter->buffer_iter);
3201 seq_release_private(inode, file);
3202
3203 return 0;
3204}
3205
3206static int tracing_release_generic_tr(struct inode *inode, struct file *file)
3207{
3208 struct trace_array *tr = inode->i_private;
3209
3210 trace_array_put(tr);
3211 return 0;
3212}
3213
3214static int tracing_single_release_tr(struct inode *inode, struct file *file)
3215{
3216 struct trace_array *tr = inode->i_private;
3217
3218 trace_array_put(tr);
3219
3220 return single_release(inode, file);
3221}
3222
3223static int tracing_open(struct inode *inode, struct file *file)
3224{
3225 struct trace_array *tr = inode->i_private;
3226 struct trace_iterator *iter;
3227 int ret = 0;
3228
3229 if (trace_array_get(tr) < 0)
3230 return -ENODEV;
3231
3232 /* If this file was open for write, then erase contents */
3233 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
3234 int cpu = tracing_get_cpu(inode);
3235
3236 if (cpu == RING_BUFFER_ALL_CPUS)
3237 tracing_reset_online_cpus(&tr->trace_buffer);
3238 else
3239 tracing_reset(&tr->trace_buffer, cpu);
3240 }
3241
3242 if (file->f_mode & FMODE_READ) {
3243 iter = __tracing_open(inode, file, false);
3244 if (IS_ERR(iter))
3245 ret = PTR_ERR(iter);
3246 else if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
3247 iter->iter_flags |= TRACE_FILE_LAT_FMT;
3248 }
3249
3250 if (ret < 0)
3251 trace_array_put(tr);
3252
3253 return ret;
3254}
3255
3256/*
3257 * Some tracers are not suitable for instance buffers.
3258 * A tracer is always available for the global array (toplevel)
3259 * or if it explicitly states that it is.
3260 */
3261static bool
3262trace_ok_for_array(struct tracer *t, struct trace_array *tr)
3263{
3264 return (tr->flags & TRACE_ARRAY_FL_GLOBAL) || t->allow_instances;
3265}
3266
3267/* Find the next tracer that this trace array may use */
3268static struct tracer *
3269get_tracer_for_array(struct trace_array *tr, struct tracer *t)
3270{
3271 while (t && !trace_ok_for_array(t, tr))
3272 t = t->next;
3273
3274 return t;
3275}
3276
3277static void *
3278t_next(struct seq_file *m, void *v, loff_t *pos)
3279{
3280 struct trace_array *tr = m->private;
3281 struct tracer *t = v;
3282
3283 (*pos)++;
3284
3285 if (t)
3286 t = get_tracer_for_array(tr, t->next);
3287
3288 return t;
3289}
3290
3291static void *t_start(struct seq_file *m, loff_t *pos)
3292{
3293 struct trace_array *tr = m->private;
3294 struct tracer *t;
3295 loff_t l = 0;
3296
3297 mutex_lock(&trace_types_lock);
3298
3299 t = get_tracer_for_array(tr, trace_types);
3300 for (; t && l < *pos; t = t_next(m, t, &l))
3301 ;
3302
3303 return t;
3304}
3305
3306static void t_stop(struct seq_file *m, void *p)
3307{
3308 mutex_unlock(&trace_types_lock);
3309}
3310
3311static int t_show(struct seq_file *m, void *v)
3312{
3313 struct tracer *t = v;
3314
3315 if (!t)
3316 return 0;
3317
3318 seq_puts(m, t->name);
3319 if (t->next)
3320 seq_putc(m, ' ');
3321 else
3322 seq_putc(m, '\n');
3323
3324 return 0;
3325}
3326
3327static const struct seq_operations show_traces_seq_ops = {
3328 .start = t_start,
3329 .next = t_next,
3330 .stop = t_stop,
3331 .show = t_show,
3332};
3333
3334static int show_traces_open(struct inode *inode, struct file *file)
3335{
3336 struct trace_array *tr = inode->i_private;
3337 struct seq_file *m;
3338 int ret;
3339
3340 if (tracing_disabled)
3341 return -ENODEV;
3342
3343 ret = seq_open(file, &show_traces_seq_ops);
3344 if (ret)
3345 return ret;
3346
3347 m = file->private_data;
3348 m->private = tr;
3349
3350 return 0;
3351}
3352
3353static ssize_t
3354tracing_write_stub(struct file *filp, const char __user *ubuf,
3355 size_t count, loff_t *ppos)
3356{
3357 return count;
3358}
3359
3360loff_t tracing_lseek(struct file *file, loff_t offset, int whence)
3361{
3362 int ret;
3363
3364 if (file->f_mode & FMODE_READ)
3365 ret = seq_lseek(file, offset, whence);
3366 else
3367 file->f_pos = ret = 0;
3368
3369 return ret;
3370}
3371
3372static const struct file_operations tracing_fops = {
3373 .open = tracing_open,
3374 .read = seq_read,
3375 .write = tracing_write_stub,
3376 .llseek = tracing_lseek,
3377 .release = tracing_release,
3378};
3379
3380static const struct file_operations show_traces_fops = {
3381 .open = show_traces_open,
3382 .read = seq_read,
3383 .release = seq_release,
3384 .llseek = seq_lseek,
3385};
3386
3387/*
3388 * The tracer itself will not take this lock, but still we want
3389 * to provide a consistent cpumask to user-space:
3390 */
3391static DEFINE_MUTEX(tracing_cpumask_update_lock);
3392
3393/*
3394 * Temporary storage for the character representation of the
3395 * CPU bitmask (and one more byte for the newline):
3396 */
3397static char mask_str[NR_CPUS + 1];
3398
3399static ssize_t
3400tracing_cpumask_read(struct file *filp, char __user *ubuf,
3401 size_t count, loff_t *ppos)
3402{
3403 struct trace_array *tr = file_inode(filp)->i_private;
3404 int len;
3405
3406 mutex_lock(&tracing_cpumask_update_lock);
3407
3408 len = snprintf(mask_str, count, "%*pb\n",
3409 cpumask_pr_args(tr->tracing_cpumask));
3410 if (len >= count) {
3411 count = -EINVAL;
3412 goto out_err;
3413 }
3414 count = simple_read_from_buffer(ubuf, count, ppos, mask_str, NR_CPUS+1);
3415
3416out_err:
3417 mutex_unlock(&tracing_cpumask_update_lock);
3418
3419 return count;
3420}
3421
3422static ssize_t
3423tracing_cpumask_write(struct file *filp, const char __user *ubuf,
3424 size_t count, loff_t *ppos)
3425{
3426 struct trace_array *tr = file_inode(filp)->i_private;
3427 cpumask_var_t tracing_cpumask_new;
3428 int err, cpu;
3429
3430 if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
3431 return -ENOMEM;
3432
3433 err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
3434 if (err)
3435 goto err_unlock;
3436
3437 mutex_lock(&tracing_cpumask_update_lock);
3438
3439 local_irq_disable();
3440 arch_spin_lock(&tr->max_lock);
3441 for_each_tracing_cpu(cpu) {
3442 /*
3443 * Increase/decrease the disabled counter if we are
3444 * about to flip a bit in the cpumask:
3445 */
3446 if (cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
3447 !cpumask_test_cpu(cpu, tracing_cpumask_new)) {
3448 atomic_inc(&per_cpu_ptr(tr->trace_buffer.data, cpu)->disabled);
3449 ring_buffer_record_disable_cpu(tr->trace_buffer.buffer, cpu);
3450 }
3451 if (!cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
3452 cpumask_test_cpu(cpu, tracing_cpumask_new)) {
3453 atomic_dec(&per_cpu_ptr(tr->trace_buffer.data, cpu)->disabled);
3454 ring_buffer_record_enable_cpu(tr->trace_buffer.buffer, cpu);
3455 }
3456 }
3457 arch_spin_unlock(&tr->max_lock);
3458 local_irq_enable();
3459
3460 cpumask_copy(tr->tracing_cpumask, tracing_cpumask_new);
3461
3462 mutex_unlock(&tracing_cpumask_update_lock);
3463 free_cpumask_var(tracing_cpumask_new);
3464
3465 return count;
3466
3467err_unlock:
3468 free_cpumask_var(tracing_cpumask_new);
3469
3470 return err;
3471}
3472
3473static const struct file_operations tracing_cpumask_fops = {
3474 .open = tracing_open_generic_tr,
3475 .read = tracing_cpumask_read,
3476 .write = tracing_cpumask_write,
3477 .release = tracing_release_generic_tr,
3478 .llseek = generic_file_llseek,
3479};
3480
3481static int tracing_trace_options_show(struct seq_file *m, void *v)
3482{
3483 struct tracer_opt *trace_opts;
3484 struct trace_array *tr = m->private;
3485 u32 tracer_flags;
3486 int i;
3487
3488 mutex_lock(&trace_types_lock);
3489 tracer_flags = tr->current_trace->flags->val;
3490 trace_opts = tr->current_trace->flags->opts;
3491
3492 for (i = 0; trace_options[i]; i++) {
3493 if (tr->trace_flags & (1 << i))
3494 seq_printf(m, "%s\n", trace_options[i]);
3495 else
3496 seq_printf(m, "no%s\n", trace_options[i]);
3497 }
3498
3499 for (i = 0; trace_opts[i].name; i++) {
3500 if (tracer_flags & trace_opts[i].bit)
3501 seq_printf(m, "%s\n", trace_opts[i].name);
3502 else
3503 seq_printf(m, "no%s\n", trace_opts[i].name);
3504 }
3505 mutex_unlock(&trace_types_lock);
3506
3507 return 0;
3508}
3509
3510static int __set_tracer_option(struct trace_array *tr,
3511 struct tracer_flags *tracer_flags,
3512 struct tracer_opt *opts, int neg)
3513{
3514 struct tracer *trace = tracer_flags->trace;
3515 int ret;
3516
3517 ret = trace->set_flag(tr, tracer_flags->val, opts->bit, !neg);
3518 if (ret)
3519 return ret;
3520
3521 if (neg)
3522 tracer_flags->val &= ~opts->bit;
3523 else
3524 tracer_flags->val |= opts->bit;
3525 return 0;
3526}
3527
3528/* Try to assign a tracer specific option */
3529static int set_tracer_option(struct trace_array *tr, char *cmp, int neg)
3530{
3531 struct tracer *trace = tr->current_trace;
3532 struct tracer_flags *tracer_flags = trace->flags;
3533 struct tracer_opt *opts = NULL;
3534 int i;
3535
3536 for (i = 0; tracer_flags->opts[i].name; i++) {
3537 opts = &tracer_flags->opts[i];
3538
3539 if (strcmp(cmp, opts->name) == 0)
3540 return __set_tracer_option(tr, trace->flags, opts, neg);
3541 }
3542
3543 return -EINVAL;
3544}
3545
3546/* Some tracers require overwrite to stay enabled */
3547int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set)
3548{
3549 if (tracer->enabled && (mask & TRACE_ITER_OVERWRITE) && !set)
3550 return -1;
3551
3552 return 0;
3553}
3554
3555int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled)
3556{
3557 /* do nothing if flag is already set */
3558 if (!!(tr->trace_flags & mask) == !!enabled)
3559 return 0;
3560
3561 /* Give the tracer a chance to approve the change */
3562 if (tr->current_trace->flag_changed)
3563 if (tr->current_trace->flag_changed(tr, mask, !!enabled))
3564 return -EINVAL;
3565
3566 if (enabled)
3567 tr->trace_flags |= mask;
3568 else
3569 tr->trace_flags &= ~mask;
3570
3571 if (mask == TRACE_ITER_RECORD_CMD)
3572 trace_event_enable_cmd_record(enabled);
3573
3574 if (mask == TRACE_ITER_OVERWRITE) {
3575 ring_buffer_change_overwrite(tr->trace_buffer.buffer, enabled);
3576#ifdef CONFIG_TRACER_MAX_TRACE
3577 ring_buffer_change_overwrite(tr->max_buffer.buffer, enabled);
3578#endif
3579 }
3580
3581 if (mask == TRACE_ITER_PRINTK) {
3582 trace_printk_start_stop_comm(enabled);
3583 trace_printk_control(enabled);
3584 }
3585
3586 return 0;
3587}
3588
3589static int trace_set_options(struct trace_array *tr, char *option)
3590{
3591 char *cmp;
3592 int neg = 0;
3593 int ret = -ENODEV;
3594 int i;
3595 size_t orig_len = strlen(option);
3596
3597 cmp = strstrip(option);
3598
3599 if (strncmp(cmp, "no", 2) == 0) {
3600 neg = 1;
3601 cmp += 2;
3602 }
3603
3604 mutex_lock(&trace_types_lock);
3605
3606 for (i = 0; trace_options[i]; i++) {
3607 if (strcmp(cmp, trace_options[i]) == 0) {
3608 ret = set_tracer_flag(tr, 1 << i, !neg);
3609 break;
3610 }
3611 }
3612
3613 /* If no option could be set, test the specific tracer options */
3614 if (!trace_options[i])
3615 ret = set_tracer_option(tr, cmp, neg);
3616
3617 mutex_unlock(&trace_types_lock);
3618
3619 /*
3620 * If the first trailing whitespace is replaced with '\0' by strstrip,
3621 * turn it back into a space.
3622 */
3623 if (orig_len > strlen(option))
3624 option[strlen(option)] = ' ';
3625
3626 return ret;
3627}
3628
3629static void __init apply_trace_boot_options(void)
3630{
3631 char *buf = trace_boot_options_buf;
3632 char *option;
3633
3634 while (true) {
3635 option = strsep(&buf, ",");
3636
3637 if (!option)
3638 break;
3639
3640 if (*option)
3641 trace_set_options(&global_trace, option);
3642
3643 /* Put back the comma to allow this to be called again */
3644 if (buf)
3645 *(buf - 1) = ',';
3646 }
3647}
3648
3649static ssize_t
3650tracing_trace_options_write(struct file *filp, const char __user *ubuf,
3651 size_t cnt, loff_t *ppos)
3652{
3653 struct seq_file *m = filp->private_data;
3654 struct trace_array *tr = m->private;
3655 char buf[64];
3656 int ret;
3657
3658 if (cnt >= sizeof(buf))
3659 return -EINVAL;
3660
3661 if (copy_from_user(&buf, ubuf, cnt))
3662 return -EFAULT;
3663
3664 buf[cnt] = 0;
3665
3666 ret = trace_set_options(tr, buf);
3667 if (ret < 0)
3668 return ret;
3669
3670 *ppos += cnt;
3671
3672 return cnt;
3673}
3674
3675static int tracing_trace_options_open(struct inode *inode, struct file *file)
3676{
3677 struct trace_array *tr = inode->i_private;
3678 int ret;
3679
3680 if (tracing_disabled)
3681 return -ENODEV;
3682
3683 if (trace_array_get(tr) < 0)
3684 return -ENODEV;
3685
3686 ret = single_open(file, tracing_trace_options_show, inode->i_private);
3687 if (ret < 0)
3688 trace_array_put(tr);
3689
3690 return ret;
3691}
3692
3693static const struct file_operations tracing_iter_fops = {
3694 .open = tracing_trace_options_open,
3695 .read = seq_read,
3696 .llseek = seq_lseek,
3697 .release = tracing_single_release_tr,
3698 .write = tracing_trace_options_write,
3699};
3700
3701static const char readme_msg[] =
3702 "tracing mini-HOWTO:\n\n"
3703 "# echo 0 > tracing_on : quick way to disable tracing\n"
3704 "# echo 1 > tracing_on : quick way to re-enable tracing\n\n"
3705 " Important files:\n"
3706 " trace\t\t\t- The static contents of the buffer\n"
3707 "\t\t\t To clear the buffer write into this file: echo > trace\n"
3708 " trace_pipe\t\t- A consuming read to see the contents of the buffer\n"
3709 " current_tracer\t- function and latency tracers\n"
3710 " available_tracers\t- list of configured tracers for current_tracer\n"
3711 " buffer_size_kb\t- view and modify size of per cpu buffer\n"
3712 " buffer_total_size_kb - view total size of all cpu buffers\n\n"
3713 " trace_clock\t\t-change the clock used to order events\n"
3714 " local: Per cpu clock but may not be synced across CPUs\n"
3715 " global: Synced across CPUs but slows tracing down.\n"
3716 " counter: Not a clock, but just an increment\n"
3717 " uptime: Jiffy counter from time of boot\n"
3718 " perf: Same clock that perf events use\n"
3719#ifdef CONFIG_X86_64
3720 " x86-tsc: TSC cycle counter\n"
3721#endif
3722 "\n trace_marker\t\t- Writes into this file writes into the kernel buffer\n"
3723 " tracing_cpumask\t- Limit which CPUs to trace\n"
3724 " instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
3725 "\t\t\t Remove sub-buffer with rmdir\n"
3726 " trace_options\t\t- Set format or modify how tracing happens\n"
3727 "\t\t\t Disable an option by adding a suffix 'no' to the\n"
3728 "\t\t\t option name\n"
3729 " saved_cmdlines_size\t- echo command number in here to store comm-pid list\n"
3730#ifdef CONFIG_DYNAMIC_FTRACE
3731 "\n available_filter_functions - list of functions that can be filtered on\n"
3732 " set_ftrace_filter\t- echo function name in here to only trace these\n"
3733 "\t\t\t functions\n"
3734 "\t accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
3735 "\t modules: Can select a group via module\n"
3736 "\t Format: :mod:<module-name>\n"
3737 "\t example: echo :mod:ext3 > set_ftrace_filter\n"
3738 "\t triggers: a command to perform when function is hit\n"
3739 "\t Format: <function>:<trigger>[:count]\n"
3740 "\t trigger: traceon, traceoff\n"
3741 "\t\t enable_event:<system>:<event>\n"
3742 "\t\t disable_event:<system>:<event>\n"
3743#ifdef CONFIG_STACKTRACE
3744 "\t\t stacktrace\n"
3745#endif
3746#ifdef CONFIG_TRACER_SNAPSHOT
3747 "\t\t snapshot\n"
3748#endif
3749 "\t\t dump\n"
3750 "\t\t cpudump\n"
3751 "\t example: echo do_fault:traceoff > set_ftrace_filter\n"
3752 "\t echo do_trap:traceoff:3 > set_ftrace_filter\n"
3753 "\t The first one will disable tracing every time do_fault is hit\n"
3754 "\t The second will disable tracing at most 3 times when do_trap is hit\n"
3755 "\t The first time do trap is hit and it disables tracing, the\n"
3756 "\t counter will decrement to 2. If tracing is already disabled,\n"
3757 "\t the counter will not decrement. It only decrements when the\n"
3758 "\t trigger did work\n"
3759 "\t To remove trigger without count:\n"
3760 "\t echo '!<function>:<trigger> > set_ftrace_filter\n"
3761 "\t To remove trigger with a count:\n"
3762 "\t echo '!<function>:<trigger>:0 > set_ftrace_filter\n"
3763 " set_ftrace_notrace\t- echo function name in here to never trace.\n"
3764 "\t accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
3765 "\t modules: Can select a group via module command :mod:\n"
3766 "\t Does not accept triggers\n"
3767#endif /* CONFIG_DYNAMIC_FTRACE */
3768#ifdef CONFIG_FUNCTION_TRACER
3769 " set_ftrace_pid\t- Write pid(s) to only function trace those pids\n"
3770 "\t\t (function)\n"
3771#endif
3772#ifdef CONFIG_FUNCTION_GRAPH_TRACER
3773 " set_graph_function\t- Trace the nested calls of a function (function_graph)\n"
3774 " set_graph_notrace\t- Do not trace the nested calls of a function (function_graph)\n"
3775 " max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n"
3776#endif
3777#ifdef CONFIG_TRACER_SNAPSHOT
3778 "\n snapshot\t\t- Like 'trace' but shows the content of the static\n"
3779 "\t\t\t snapshot buffer. Read the contents for more\n"
3780 "\t\t\t information\n"
3781#endif
3782#ifdef CONFIG_STACK_TRACER
3783 " stack_trace\t\t- Shows the max stack trace when active\n"
3784 " stack_max_size\t- Shows current max stack size that was traced\n"
3785 "\t\t\t Write into this file to reset the max size (trigger a\n"
3786 "\t\t\t new trace)\n"
3787#ifdef CONFIG_DYNAMIC_FTRACE
3788 " stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace\n"
3789 "\t\t\t traces\n"
3790#endif
3791#endif /* CONFIG_STACK_TRACER */
3792 " events/\t\t- Directory containing all trace event subsystems:\n"
3793 " enable\t\t- Write 0/1 to enable/disable tracing of all events\n"
3794 " events/<system>/\t- Directory containing all trace events for <system>:\n"
3795 " enable\t\t- Write 0/1 to enable/disable tracing of all <system>\n"
3796 "\t\t\t events\n"
3797 " filter\t\t- If set, only events passing filter are traced\n"
3798 " events/<system>/<event>/\t- Directory containing control files for\n"
3799 "\t\t\t <event>:\n"
3800 " enable\t\t- Write 0/1 to enable/disable tracing of <event>\n"
3801 " filter\t\t- If set, only events passing filter are traced\n"
3802 " trigger\t\t- If set, a command to perform when event is hit\n"
3803 "\t Format: <trigger>[:count][if <filter>]\n"
3804 "\t trigger: traceon, traceoff\n"
3805 "\t enable_event:<system>:<event>\n"
3806 "\t disable_event:<system>:<event>\n"
3807#ifdef CONFIG_STACKTRACE
3808 "\t\t stacktrace\n"
3809#endif
3810#ifdef CONFIG_TRACER_SNAPSHOT
3811 "\t\t snapshot\n"
3812#endif
3813 "\t example: echo traceoff > events/block/block_unplug/trigger\n"
3814 "\t echo traceoff:3 > events/block/block_unplug/trigger\n"
3815 "\t echo 'enable_event:kmem:kmalloc:3 if nr_rq > 1' > \\\n"
3816 "\t events/block/block_unplug/trigger\n"
3817 "\t The first disables tracing every time block_unplug is hit.\n"
3818 "\t The second disables tracing the first 3 times block_unplug is hit.\n"
3819 "\t The third enables the kmalloc event the first 3 times block_unplug\n"
3820 "\t is hit and has value of greater than 1 for the 'nr_rq' event field.\n"
3821 "\t Like function triggers, the counter is only decremented if it\n"
3822 "\t enabled or disabled tracing.\n"
3823 "\t To remove a trigger without a count:\n"
3824 "\t echo '!<trigger> > <system>/<event>/trigger\n"
3825 "\t To remove a trigger with a count:\n"
3826 "\t echo '!<trigger>:0 > <system>/<event>/trigger\n"
3827 "\t Filters can be ignored when removing a trigger.\n"
3828;
3829
3830static ssize_t
3831tracing_readme_read(struct file *filp, char __user *ubuf,
3832 size_t cnt, loff_t *ppos)
3833{
3834 return simple_read_from_buffer(ubuf, cnt, ppos,
3835 readme_msg, strlen(readme_msg));
3836}
3837
3838static const struct file_operations tracing_readme_fops = {
3839 .open = tracing_open_generic,
3840 .read = tracing_readme_read,
3841 .llseek = generic_file_llseek,
3842};
3843
3844static void *saved_cmdlines_next(struct seq_file *m, void *v, loff_t *pos)
3845{
3846 unsigned int *ptr = v;
3847
3848 if (*pos || m->count)
3849 ptr++;
3850
3851 (*pos)++;
3852
3853 for (; ptr < &savedcmd->map_cmdline_to_pid[savedcmd->cmdline_num];
3854 ptr++) {
3855 if (*ptr == -1 || *ptr == NO_CMDLINE_MAP)
3856 continue;
3857
3858 return ptr;
3859 }
3860
3861 return NULL;
3862}
3863
3864static void *saved_cmdlines_start(struct seq_file *m, loff_t *pos)
3865{
3866 void *v;
3867 loff_t l = 0;
3868
3869 preempt_disable();
3870 arch_spin_lock(&trace_cmdline_lock);
3871
3872 v = &savedcmd->map_cmdline_to_pid[0];
3873 while (l <= *pos) {
3874 v = saved_cmdlines_next(m, v, &l);
3875 if (!v)
3876 return NULL;
3877 }
3878
3879 return v;
3880}
3881
3882static void saved_cmdlines_stop(struct seq_file *m, void *v)
3883{
3884 arch_spin_unlock(&trace_cmdline_lock);
3885 preempt_enable();
3886}
3887
3888static int saved_cmdlines_show(struct seq_file *m, void *v)
3889{
3890 char buf[TASK_COMM_LEN];
3891 unsigned int *pid = v;
3892
3893 __trace_find_cmdline(*pid, buf);
3894 seq_printf(m, "%d %s\n", *pid, buf);
3895 return 0;
3896}
3897
3898static const struct seq_operations tracing_saved_cmdlines_seq_ops = {
3899 .start = saved_cmdlines_start,
3900 .next = saved_cmdlines_next,
3901 .stop = saved_cmdlines_stop,
3902 .show = saved_cmdlines_show,
3903};
3904
3905static int tracing_saved_cmdlines_open(struct inode *inode, struct file *filp)
3906{
3907 if (tracing_disabled)
3908 return -ENODEV;
3909
3910 return seq_open(filp, &tracing_saved_cmdlines_seq_ops);
3911}
3912
3913static const struct file_operations tracing_saved_cmdlines_fops = {
3914 .open = tracing_saved_cmdlines_open,
3915 .read = seq_read,
3916 .llseek = seq_lseek,
3917 .release = seq_release,
3918};
3919
3920static ssize_t
3921tracing_saved_cmdlines_size_read(struct file *filp, char __user *ubuf,
3922 size_t cnt, loff_t *ppos)
3923{
3924 char buf[64];
3925 int r;
3926
3927 arch_spin_lock(&trace_cmdline_lock);
3928 r = scnprintf(buf, sizeof(buf), "%u\n", savedcmd->cmdline_num);
3929 arch_spin_unlock(&trace_cmdline_lock);
3930
3931 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
3932}
3933
3934static void free_saved_cmdlines_buffer(struct saved_cmdlines_buffer *s)
3935{
3936 kfree(s->saved_cmdlines);
3937 kfree(s->map_cmdline_to_pid);
3938 kfree(s);
3939}
3940
3941static int tracing_resize_saved_cmdlines(unsigned int val)
3942{
3943 struct saved_cmdlines_buffer *s, *savedcmd_temp;
3944
3945 s = kmalloc(sizeof(*s), GFP_KERNEL);
3946 if (!s)
3947 return -ENOMEM;
3948
3949 if (allocate_cmdlines_buffer(val, s) < 0) {
3950 kfree(s);
3951 return -ENOMEM;
3952 }
3953
3954 arch_spin_lock(&trace_cmdline_lock);
3955 savedcmd_temp = savedcmd;
3956 savedcmd = s;
3957 arch_spin_unlock(&trace_cmdline_lock);
3958 free_saved_cmdlines_buffer(savedcmd_temp);
3959
3960 return 0;
3961}
3962
3963static ssize_t
3964tracing_saved_cmdlines_size_write(struct file *filp, const char __user *ubuf,
3965 size_t cnt, loff_t *ppos)
3966{
3967 unsigned long val;
3968 int ret;
3969
3970 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
3971 if (ret)
3972 return ret;
3973
3974 /* must have at least 1 entry or less than PID_MAX_DEFAULT */
3975 if (!val || val > PID_MAX_DEFAULT)
3976 return -EINVAL;
3977
3978 ret = tracing_resize_saved_cmdlines((unsigned int)val);
3979 if (ret < 0)
3980 return ret;
3981
3982 *ppos += cnt;
3983
3984 return cnt;
3985}
3986
3987static const struct file_operations tracing_saved_cmdlines_size_fops = {
3988 .open = tracing_open_generic,
3989 .read = tracing_saved_cmdlines_size_read,
3990 .write = tracing_saved_cmdlines_size_write,
3991};
3992
3993#ifdef CONFIG_TRACE_ENUM_MAP_FILE
3994static union trace_enum_map_item *
3995update_enum_map(union trace_enum_map_item *ptr)
3996{
3997 if (!ptr->map.enum_string) {
3998 if (ptr->tail.next) {
3999 ptr = ptr->tail.next;
4000 /* Set ptr to the next real item (skip head) */
4001 ptr++;
4002 } else
4003 return NULL;
4004 }
4005 return ptr;
4006}
4007
4008static void *enum_map_next(struct seq_file *m, void *v, loff_t *pos)
4009{
4010 union trace_enum_map_item *ptr = v;
4011
4012 /*
4013 * Paranoid! If ptr points to end, we don't want to increment past it.
4014 * This really should never happen.
4015 */
4016 ptr = update_enum_map(ptr);
4017 if (WARN_ON_ONCE(!ptr))
4018 return NULL;
4019
4020 ptr++;
4021
4022 (*pos)++;
4023
4024 ptr = update_enum_map(ptr);
4025
4026 return ptr;
4027}
4028
4029static void *enum_map_start(struct seq_file *m, loff_t *pos)
4030{
4031 union trace_enum_map_item *v;
4032 loff_t l = 0;
4033
4034 mutex_lock(&trace_enum_mutex);
4035
4036 v = trace_enum_maps;
4037 if (v)
4038 v++;
4039
4040 while (v && l < *pos) {
4041 v = enum_map_next(m, v, &l);
4042 }
4043
4044 return v;
4045}
4046
4047static void enum_map_stop(struct seq_file *m, void *v)
4048{
4049 mutex_unlock(&trace_enum_mutex);
4050}
4051
4052static int enum_map_show(struct seq_file *m, void *v)
4053{
4054 union trace_enum_map_item *ptr = v;
4055
4056 seq_printf(m, "%s %ld (%s)\n",
4057 ptr->map.enum_string, ptr->map.enum_value,
4058 ptr->map.system);
4059
4060 return 0;
4061}
4062
4063static const struct seq_operations tracing_enum_map_seq_ops = {
4064 .start = enum_map_start,
4065 .next = enum_map_next,
4066 .stop = enum_map_stop,
4067 .show = enum_map_show,
4068};
4069
4070static int tracing_enum_map_open(struct inode *inode, struct file *filp)
4071{
4072 if (tracing_disabled)
4073 return -ENODEV;
4074
4075 return seq_open(filp, &tracing_enum_map_seq_ops);
4076}
4077
4078static const struct file_operations tracing_enum_map_fops = {
4079 .open = tracing_enum_map_open,
4080 .read = seq_read,
4081 .llseek = seq_lseek,
4082 .release = seq_release,
4083};
4084
4085static inline union trace_enum_map_item *
4086trace_enum_jmp_to_tail(union trace_enum_map_item *ptr)
4087{
4088 /* Return tail of array given the head */
4089 return ptr + ptr->head.length + 1;
4090}
4091
4092static void
4093trace_insert_enum_map_file(struct module *mod, struct trace_enum_map **start,
4094 int len)
4095{
4096 struct trace_enum_map **stop;
4097 struct trace_enum_map **map;
4098 union trace_enum_map_item *map_array;
4099 union trace_enum_map_item *ptr;
4100
4101 stop = start + len;
4102
4103 /*
4104 * The trace_enum_maps contains the map plus a head and tail item,
4105 * where the head holds the module and length of array, and the
4106 * tail holds a pointer to the next list.
4107 */
4108 map_array = kmalloc(sizeof(*map_array) * (len + 2), GFP_KERNEL);
4109 if (!map_array) {
4110 pr_warn("Unable to allocate trace enum mapping\n");
4111 return;
4112 }
4113
4114 mutex_lock(&trace_enum_mutex);
4115
4116 if (!trace_enum_maps)
4117 trace_enum_maps = map_array;
4118 else {
4119 ptr = trace_enum_maps;
4120 for (;;) {
4121 ptr = trace_enum_jmp_to_tail(ptr);
4122 if (!ptr->tail.next)
4123 break;
4124 ptr = ptr->tail.next;
4125
4126 }
4127 ptr->tail.next = map_array;
4128 }
4129 map_array->head.mod = mod;
4130 map_array->head.length = len;
4131 map_array++;
4132
4133 for (map = start; (unsigned long)map < (unsigned long)stop; map++) {
4134 map_array->map = **map;
4135 map_array++;
4136 }
4137 memset(map_array, 0, sizeof(*map_array));
4138
4139 mutex_unlock(&trace_enum_mutex);
4140}
4141
4142static void trace_create_enum_file(struct dentry *d_tracer)
4143{
4144 trace_create_file("enum_map", 0444, d_tracer,
4145 NULL, &tracing_enum_map_fops);
4146}
4147
4148#else /* CONFIG_TRACE_ENUM_MAP_FILE */
4149static inline void trace_create_enum_file(struct dentry *d_tracer) { }
4150static inline void trace_insert_enum_map_file(struct module *mod,
4151 struct trace_enum_map **start, int len) { }
4152#endif /* !CONFIG_TRACE_ENUM_MAP_FILE */
4153
4154static void trace_insert_enum_map(struct module *mod,
4155 struct trace_enum_map **start, int len)
4156{
4157 struct trace_enum_map **map;
4158
4159 if (len <= 0)
4160 return;
4161
4162 map = start;
4163
4164 trace_event_enum_update(map, len);
4165
4166 trace_insert_enum_map_file(mod, start, len);
4167}
4168
4169static ssize_t
4170tracing_set_trace_read(struct file *filp, char __user *ubuf,
4171 size_t cnt, loff_t *ppos)
4172{
4173 struct trace_array *tr = filp->private_data;
4174 char buf[MAX_TRACER_SIZE+2];
4175 int r;
4176
4177 mutex_lock(&trace_types_lock);
4178 r = sprintf(buf, "%s\n", tr->current_trace->name);
4179 mutex_unlock(&trace_types_lock);
4180
4181 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
4182}
4183
4184int tracer_init(struct tracer *t, struct trace_array *tr)
4185{
4186 tracing_reset_online_cpus(&tr->trace_buffer);
4187 return t->init(tr);
4188}
4189
4190static void set_buffer_entries(struct trace_buffer *buf, unsigned long val)
4191{
4192 int cpu;
4193
4194 for_each_tracing_cpu(cpu)
4195 per_cpu_ptr(buf->data, cpu)->entries = val;
4196}
4197
4198#ifdef CONFIG_TRACER_MAX_TRACE
4199/* resize @tr's buffer to the size of @size_tr's entries */
4200static int resize_buffer_duplicate_size(struct trace_buffer *trace_buf,
4201 struct trace_buffer *size_buf, int cpu_id)
4202{
4203 int cpu, ret = 0;
4204
4205 if (cpu_id == RING_BUFFER_ALL_CPUS) {
4206 for_each_tracing_cpu(cpu) {
4207 ret = ring_buffer_resize(trace_buf->buffer,
4208 per_cpu_ptr(size_buf->data, cpu)->entries, cpu);
4209 if (ret < 0)
4210 break;
4211 per_cpu_ptr(trace_buf->data, cpu)->entries =
4212 per_cpu_ptr(size_buf->data, cpu)->entries;
4213 }
4214 } else {
4215 ret = ring_buffer_resize(trace_buf->buffer,
4216 per_cpu_ptr(size_buf->data, cpu_id)->entries, cpu_id);
4217 if (ret == 0)
4218 per_cpu_ptr(trace_buf->data, cpu_id)->entries =
4219 per_cpu_ptr(size_buf->data, cpu_id)->entries;
4220 }
4221
4222 return ret;
4223}
4224#endif /* CONFIG_TRACER_MAX_TRACE */
4225
4226static int __tracing_resize_ring_buffer(struct trace_array *tr,
4227 unsigned long size, int cpu)
4228{
4229 int ret;
4230
4231 /*
4232 * If kernel or user changes the size of the ring buffer
4233 * we use the size that was given, and we can forget about
4234 * expanding it later.
4235 */
4236 ring_buffer_expanded = true;
4237
4238 /* May be called before buffers are initialized */
4239 if (!tr->trace_buffer.buffer)
4240 return 0;
4241
4242 ret = ring_buffer_resize(tr->trace_buffer.buffer, size, cpu);
4243 if (ret < 0)
4244 return ret;
4245
4246#ifdef CONFIG_TRACER_MAX_TRACE
4247 if (!(tr->flags & TRACE_ARRAY_FL_GLOBAL) ||
4248 !tr->current_trace->use_max_tr)
4249 goto out;
4250
4251 ret = ring_buffer_resize(tr->max_buffer.buffer, size, cpu);
4252 if (ret < 0) {
4253 int r = resize_buffer_duplicate_size(&tr->trace_buffer,
4254 &tr->trace_buffer, cpu);
4255 if (r < 0) {
4256 /*
4257 * AARGH! We are left with different
4258 * size max buffer!!!!
4259 * The max buffer is our "snapshot" buffer.
4260 * When a tracer needs a snapshot (one of the
4261 * latency tracers), it swaps the max buffer
4262 * with the saved snap shot. We succeeded to
4263 * update the size of the main buffer, but failed to
4264 * update the size of the max buffer. But when we tried
4265 * to reset the main buffer to the original size, we
4266 * failed there too. This is very unlikely to
4267 * happen, but if it does, warn and kill all
4268 * tracing.
4269 */
4270 WARN_ON(1);
4271 tracing_disabled = 1;
4272 }
4273 return ret;
4274 }
4275
4276 if (cpu == RING_BUFFER_ALL_CPUS)
4277 set_buffer_entries(&tr->max_buffer, size);
4278 else
4279 per_cpu_ptr(tr->max_buffer.data, cpu)->entries = size;
4280
4281 out:
4282#endif /* CONFIG_TRACER_MAX_TRACE */
4283
4284 if (cpu == RING_BUFFER_ALL_CPUS)
4285 set_buffer_entries(&tr->trace_buffer, size);
4286 else
4287 per_cpu_ptr(tr->trace_buffer.data, cpu)->entries = size;
4288
4289 return ret;
4290}
4291
4292static ssize_t tracing_resize_ring_buffer(struct trace_array *tr,
4293 unsigned long size, int cpu_id)
4294{
4295 int ret = size;
4296
4297 mutex_lock(&trace_types_lock);
4298
4299 if (cpu_id != RING_BUFFER_ALL_CPUS) {
4300 /* make sure, this cpu is enabled in the mask */
4301 if (!cpumask_test_cpu(cpu_id, tracing_buffer_mask)) {
4302 ret = -EINVAL;
4303 goto out;
4304 }
4305 }
4306
4307 ret = __tracing_resize_ring_buffer(tr, size, cpu_id);
4308 if (ret < 0)
4309 ret = -ENOMEM;
4310
4311out:
4312 mutex_unlock(&trace_types_lock);
4313
4314 return ret;
4315}
4316
4317
4318/**
4319 * tracing_update_buffers - used by tracing facility to expand ring buffers
4320 *
4321 * To save on memory when the tracing is never used on a system with it
4322 * configured in. The ring buffers are set to a minimum size. But once
4323 * a user starts to use the tracing facility, then they need to grow
4324 * to their default size.
4325 *
4326 * This function is to be called when a tracer is about to be used.
4327 */
4328int tracing_update_buffers(void)
4329{
4330 int ret = 0;
4331
4332 mutex_lock(&trace_types_lock);
4333 if (!ring_buffer_expanded)
4334 ret = __tracing_resize_ring_buffer(&global_trace, trace_buf_size,
4335 RING_BUFFER_ALL_CPUS);
4336 mutex_unlock(&trace_types_lock);
4337
4338 return ret;
4339}
4340
4341struct trace_option_dentry;
4342
4343static void
4344create_trace_option_files(struct trace_array *tr, struct tracer *tracer);
4345
4346/*
4347 * Used to clear out the tracer before deletion of an instance.
4348 * Must have trace_types_lock held.
4349 */
4350static void tracing_set_nop(struct trace_array *tr)
4351{
4352 if (tr->current_trace == &nop_trace)
4353 return;
4354
4355 tr->current_trace->enabled--;
4356
4357 if (tr->current_trace->reset)
4358 tr->current_trace->reset(tr);
4359
4360 tr->current_trace = &nop_trace;
4361}
4362
4363static void add_tracer_options(struct trace_array *tr, struct tracer *t)
4364{
4365 /* Only enable if the directory has been created already. */
4366 if (!tr->dir)
4367 return;
4368
4369 create_trace_option_files(tr, t);
4370}
4371
4372static int tracing_set_tracer(struct trace_array *tr, const char *buf)
4373{
4374 struct tracer *t;
4375#ifdef CONFIG_TRACER_MAX_TRACE
4376 bool had_max_tr;
4377#endif
4378 int ret = 0;
4379
4380 mutex_lock(&trace_types_lock);
4381
4382 if (!ring_buffer_expanded) {
4383 ret = __tracing_resize_ring_buffer(tr, trace_buf_size,
4384 RING_BUFFER_ALL_CPUS);
4385 if (ret < 0)
4386 goto out;
4387 ret = 0;
4388 }
4389
4390 for (t = trace_types; t; t = t->next) {
4391 if (strcmp(t->name, buf) == 0)
4392 break;
4393 }
4394 if (!t) {
4395 ret = -EINVAL;
4396 goto out;
4397 }
4398 if (t == tr->current_trace)
4399 goto out;
4400
4401 /* Some tracers are only allowed for the top level buffer */
4402 if (!trace_ok_for_array(t, tr)) {
4403 ret = -EINVAL;
4404 goto out;
4405 }
4406
4407 /* If trace pipe files are being read, we can't change the tracer */
4408 if (tr->current_trace->ref) {
4409 ret = -EBUSY;
4410 goto out;
4411 }
4412
4413 trace_branch_disable();
4414
4415 tr->current_trace->enabled--;
4416
4417 if (tr->current_trace->reset)
4418 tr->current_trace->reset(tr);
4419
4420 /* Current trace needs to be nop_trace before synchronize_sched */
4421 tr->current_trace = &nop_trace;
4422
4423#ifdef CONFIG_TRACER_MAX_TRACE
4424 had_max_tr = tr->allocated_snapshot;
4425
4426 if (had_max_tr && !t->use_max_tr) {
4427 /*
4428 * We need to make sure that the update_max_tr sees that
4429 * current_trace changed to nop_trace to keep it from
4430 * swapping the buffers after we resize it.
4431 * The update_max_tr is called from interrupts disabled
4432 * so a synchronized_sched() is sufficient.
4433 */
4434 synchronize_sched();
4435 free_snapshot(tr);
4436 }
4437#endif
4438
4439#ifdef CONFIG_TRACER_MAX_TRACE
4440 if (t->use_max_tr && !had_max_tr) {
4441 ret = alloc_snapshot(tr);
4442 if (ret < 0)
4443 goto out;
4444 }
4445#endif
4446
4447 if (t->init) {
4448 ret = tracer_init(t, tr);
4449 if (ret)
4450 goto out;
4451 }
4452
4453 tr->current_trace = t;
4454 tr->current_trace->enabled++;
4455 trace_branch_enable(tr);
4456 out:
4457 mutex_unlock(&trace_types_lock);
4458
4459 return ret;
4460}
4461
4462static ssize_t
4463tracing_set_trace_write(struct file *filp, const char __user *ubuf,
4464 size_t cnt, loff_t *ppos)
4465{
4466 struct trace_array *tr = filp->private_data;
4467 char buf[MAX_TRACER_SIZE+1];
4468 int i;
4469 size_t ret;
4470 int err;
4471
4472 ret = cnt;
4473
4474 if (cnt > MAX_TRACER_SIZE)
4475 cnt = MAX_TRACER_SIZE;
4476
4477 if (copy_from_user(&buf, ubuf, cnt))
4478 return -EFAULT;
4479
4480 buf[cnt] = 0;
4481
4482 /* strip ending whitespace. */
4483 for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
4484 buf[i] = 0;
4485
4486 err = tracing_set_tracer(tr, buf);
4487 if (err)
4488 return err;
4489
4490 *ppos += ret;
4491
4492 return ret;
4493}
4494
4495static ssize_t
4496tracing_nsecs_read(unsigned long *ptr, char __user *ubuf,
4497 size_t cnt, loff_t *ppos)
4498{
4499 char buf[64];
4500 int r;
4501
4502 r = snprintf(buf, sizeof(buf), "%ld\n",
4503 *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
4504 if (r > sizeof(buf))
4505 r = sizeof(buf);
4506 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
4507}
4508
4509static ssize_t
4510tracing_nsecs_write(unsigned long *ptr, const char __user *ubuf,
4511 size_t cnt, loff_t *ppos)
4512{
4513 unsigned long val;
4514 int ret;
4515
4516 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
4517 if (ret)
4518 return ret;
4519
4520 *ptr = val * 1000;
4521
4522 return cnt;
4523}
4524
4525static ssize_t
4526tracing_thresh_read(struct file *filp, char __user *ubuf,
4527 size_t cnt, loff_t *ppos)
4528{
4529 return tracing_nsecs_read(&tracing_thresh, ubuf, cnt, ppos);
4530}
4531
4532static ssize_t
4533tracing_thresh_write(struct file *filp, const char __user *ubuf,
4534 size_t cnt, loff_t *ppos)
4535{
4536 struct trace_array *tr = filp->private_data;
4537 int ret;
4538
4539 mutex_lock(&trace_types_lock);
4540 ret = tracing_nsecs_write(&tracing_thresh, ubuf, cnt, ppos);
4541 if (ret < 0)
4542 goto out;
4543
4544 if (tr->current_trace->update_thresh) {
4545 ret = tr->current_trace->update_thresh(tr);
4546 if (ret < 0)
4547 goto out;
4548 }
4549
4550 ret = cnt;
4551out:
4552 mutex_unlock(&trace_types_lock);
4553
4554 return ret;
4555}
4556
4557#ifdef CONFIG_TRACER_MAX_TRACE
4558
4559static ssize_t
4560tracing_max_lat_read(struct file *filp, char __user *ubuf,
4561 size_t cnt, loff_t *ppos)
4562{
4563 return tracing_nsecs_read(filp->private_data, ubuf, cnt, ppos);
4564}
4565
4566static ssize_t
4567tracing_max_lat_write(struct file *filp, const char __user *ubuf,
4568 size_t cnt, loff_t *ppos)
4569{
4570 return tracing_nsecs_write(filp->private_data, ubuf, cnt, ppos);
4571}
4572
4573#endif
4574
4575static int tracing_open_pipe(struct inode *inode, struct file *filp)
4576{
4577 struct trace_array *tr = inode->i_private;
4578 struct trace_iterator *iter;
4579 int ret = 0;
4580
4581 if (tracing_disabled)
4582 return -ENODEV;
4583
4584 if (trace_array_get(tr) < 0)
4585 return -ENODEV;
4586
4587 mutex_lock(&trace_types_lock);
4588
4589 /* create a buffer to store the information to pass to userspace */
4590 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
4591 if (!iter) {
4592 ret = -ENOMEM;
4593 __trace_array_put(tr);
4594 goto out;
4595 }
4596
4597 trace_seq_init(&iter->seq);
4598 iter->trace = tr->current_trace;
4599
4600 if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
4601 ret = -ENOMEM;
4602 goto fail;
4603 }
4604
4605 /* trace pipe does not show start of buffer */
4606 cpumask_setall(iter->started);
4607
4608 if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
4609 iter->iter_flags |= TRACE_FILE_LAT_FMT;
4610
4611 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
4612 if (trace_clocks[tr->clock_id].in_ns)
4613 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
4614
4615 iter->tr = tr;
4616 iter->trace_buffer = &tr->trace_buffer;
4617 iter->cpu_file = tracing_get_cpu(inode);
4618 mutex_init(&iter->mutex);
4619 filp->private_data = iter;
4620
4621 if (iter->trace->pipe_open)
4622 iter->trace->pipe_open(iter);
4623
4624 nonseekable_open(inode, filp);
4625
4626 tr->current_trace->ref++;
4627out:
4628 mutex_unlock(&trace_types_lock);
4629 return ret;
4630
4631fail:
4632 kfree(iter->trace);
4633 kfree(iter);
4634 __trace_array_put(tr);
4635 mutex_unlock(&trace_types_lock);
4636 return ret;
4637}
4638
4639static int tracing_release_pipe(struct inode *inode, struct file *file)
4640{
4641 struct trace_iterator *iter = file->private_data;
4642 struct trace_array *tr = inode->i_private;
4643
4644 mutex_lock(&trace_types_lock);
4645
4646 tr->current_trace->ref--;
4647
4648 if (iter->trace->pipe_close)
4649 iter->trace->pipe_close(iter);
4650
4651 mutex_unlock(&trace_types_lock);
4652
4653 free_cpumask_var(iter->started);
4654 mutex_destroy(&iter->mutex);
4655 kfree(iter);
4656
4657 trace_array_put(tr);
4658
4659 return 0;
4660}
4661
4662static unsigned int
4663trace_poll(struct trace_iterator *iter, struct file *filp, poll_table *poll_table)
4664{
4665 struct trace_array *tr = iter->tr;
4666
4667 /* Iterators are static, they should be filled or empty */
4668 if (trace_buffer_iter(iter, iter->cpu_file))
4669 return POLLIN | POLLRDNORM;
4670
4671 if (tr->trace_flags & TRACE_ITER_BLOCK)
4672 /*
4673 * Always select as readable when in blocking mode
4674 */
4675 return POLLIN | POLLRDNORM;
4676 else
4677 return ring_buffer_poll_wait(iter->trace_buffer->buffer, iter->cpu_file,
4678 filp, poll_table);
4679}
4680
4681static unsigned int
4682tracing_poll_pipe(struct file *filp, poll_table *poll_table)
4683{
4684 struct trace_iterator *iter = filp->private_data;
4685
4686 return trace_poll(iter, filp, poll_table);
4687}
4688
4689/* Must be called with iter->mutex held. */
4690static int tracing_wait_pipe(struct file *filp)
4691{
4692 struct trace_iterator *iter = filp->private_data;
4693 int ret;
4694
4695 while (trace_empty(iter)) {
4696
4697 if ((filp->f_flags & O_NONBLOCK)) {
4698 return -EAGAIN;
4699 }
4700
4701 /*
4702 * We block until we read something and tracing is disabled.
4703 * We still block if tracing is disabled, but we have never
4704 * read anything. This allows a user to cat this file, and
4705 * then enable tracing. But after we have read something,
4706 * we give an EOF when tracing is again disabled.
4707 *
4708 * iter->pos will be 0 if we haven't read anything.
4709 */
4710 if (!tracing_is_on() && iter->pos)
4711 break;
4712
4713 mutex_unlock(&iter->mutex);
4714
4715 ret = wait_on_pipe(iter, false);
4716
4717 mutex_lock(&iter->mutex);
4718
4719 if (ret)
4720 return ret;
4721 }
4722
4723 return 1;
4724}
4725
4726/*
4727 * Consumer reader.
4728 */
4729static ssize_t
4730tracing_read_pipe(struct file *filp, char __user *ubuf,
4731 size_t cnt, loff_t *ppos)
4732{
4733 struct trace_iterator *iter = filp->private_data;
4734 ssize_t sret;
4735
4736 /* return any leftover data */
4737 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
4738 if (sret != -EBUSY)
4739 return sret;
4740
4741 trace_seq_init(&iter->seq);
4742
4743 /*
4744 * Avoid more than one consumer on a single file descriptor
4745 * This is just a matter of traces coherency, the ring buffer itself
4746 * is protected.
4747 */
4748 mutex_lock(&iter->mutex);
4749 if (iter->trace->read) {
4750 sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
4751 if (sret)
4752 goto out;
4753 }
4754
4755waitagain:
4756 sret = tracing_wait_pipe(filp);
4757 if (sret <= 0)
4758 goto out;
4759
4760 /* stop when tracing is finished */
4761 if (trace_empty(iter)) {
4762 sret = 0;
4763 goto out;
4764 }
4765
4766 if (cnt >= PAGE_SIZE)
4767 cnt = PAGE_SIZE - 1;
4768
4769 /* reset all but tr, trace, and overruns */
4770 memset(&iter->seq, 0,
4771 sizeof(struct trace_iterator) -
4772 offsetof(struct trace_iterator, seq));
4773 cpumask_clear(iter->started);
4774 iter->pos = -1;
4775
4776 trace_event_read_lock();
4777 trace_access_lock(iter->cpu_file);
4778 while (trace_find_next_entry_inc(iter) != NULL) {
4779 enum print_line_t ret;
4780 int save_len = iter->seq.seq.len;
4781
4782 ret = print_trace_line(iter);
4783 if (ret == TRACE_TYPE_PARTIAL_LINE) {
4784 /* don't print partial lines */
4785 iter->seq.seq.len = save_len;
4786 break;
4787 }
4788 if (ret != TRACE_TYPE_NO_CONSUME)
4789 trace_consume(iter);
4790
4791 if (trace_seq_used(&iter->seq) >= cnt)
4792 break;
4793
4794 /*
4795 * Setting the full flag means we reached the trace_seq buffer
4796 * size and we should leave by partial output condition above.
4797 * One of the trace_seq_* functions is not used properly.
4798 */
4799 WARN_ONCE(iter->seq.full, "full flag set for trace type %d",
4800 iter->ent->type);
4801 }
4802 trace_access_unlock(iter->cpu_file);
4803 trace_event_read_unlock();
4804
4805 /* Now copy what we have to the user */
4806 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
4807 if (iter->seq.seq.readpos >= trace_seq_used(&iter->seq))
4808 trace_seq_init(&iter->seq);
4809
4810 /*
4811 * If there was nothing to send to user, in spite of consuming trace
4812 * entries, go back to wait for more entries.
4813 */
4814 if (sret == -EBUSY)
4815 goto waitagain;
4816
4817out:
4818 mutex_unlock(&iter->mutex);
4819
4820 return sret;
4821}
4822
4823static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
4824 unsigned int idx)
4825{
4826 __free_page(spd->pages[idx]);
4827}
4828
4829static const struct pipe_buf_operations tracing_pipe_buf_ops = {
4830 .can_merge = 0,
4831 .confirm = generic_pipe_buf_confirm,
4832 .release = generic_pipe_buf_release,
4833 .steal = generic_pipe_buf_steal,
4834 .get = generic_pipe_buf_get,
4835};
4836
4837static size_t
4838tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
4839{
4840 size_t count;
4841 int save_len;
4842 int ret;
4843
4844 /* Seq buffer is page-sized, exactly what we need. */
4845 for (;;) {
4846 save_len = iter->seq.seq.len;
4847 ret = print_trace_line(iter);
4848
4849 if (trace_seq_has_overflowed(&iter->seq)) {
4850 iter->seq.seq.len = save_len;
4851 break;
4852 }
4853
4854 /*
4855 * This should not be hit, because it should only
4856 * be set if the iter->seq overflowed. But check it
4857 * anyway to be safe.
4858 */
4859 if (ret == TRACE_TYPE_PARTIAL_LINE) {
4860 iter->seq.seq.len = save_len;
4861 break;
4862 }
4863
4864 count = trace_seq_used(&iter->seq) - save_len;
4865 if (rem < count) {
4866 rem = 0;
4867 iter->seq.seq.len = save_len;
4868 break;
4869 }
4870
4871 if (ret != TRACE_TYPE_NO_CONSUME)
4872 trace_consume(iter);
4873 rem -= count;
4874 if (!trace_find_next_entry_inc(iter)) {
4875 rem = 0;
4876 iter->ent = NULL;
4877 break;
4878 }
4879 }
4880
4881 return rem;
4882}
4883
4884static ssize_t tracing_splice_read_pipe(struct file *filp,
4885 loff_t *ppos,
4886 struct pipe_inode_info *pipe,
4887 size_t len,
4888 unsigned int flags)
4889{
4890 struct page *pages_def[PIPE_DEF_BUFFERS];
4891 struct partial_page partial_def[PIPE_DEF_BUFFERS];
4892 struct trace_iterator *iter = filp->private_data;
4893 struct splice_pipe_desc spd = {
4894 .pages = pages_def,
4895 .partial = partial_def,
4896 .nr_pages = 0, /* This gets updated below. */
4897 .nr_pages_max = PIPE_DEF_BUFFERS,
4898 .flags = flags,
4899 .ops = &tracing_pipe_buf_ops,
4900 .spd_release = tracing_spd_release_pipe,
4901 };
4902 ssize_t ret;
4903 size_t rem;
4904 unsigned int i;
4905
4906 if (splice_grow_spd(pipe, &spd))
4907 return -ENOMEM;
4908
4909 mutex_lock(&iter->mutex);
4910
4911 if (iter->trace->splice_read) {
4912 ret = iter->trace->splice_read(iter, filp,
4913 ppos, pipe, len, flags);
4914 if (ret)
4915 goto out_err;
4916 }
4917
4918 ret = tracing_wait_pipe(filp);
4919 if (ret <= 0)
4920 goto out_err;
4921
4922 if (!iter->ent && !trace_find_next_entry_inc(iter)) {
4923 ret = -EFAULT;
4924 goto out_err;
4925 }
4926
4927 trace_event_read_lock();
4928 trace_access_lock(iter->cpu_file);
4929
4930 /* Fill as many pages as possible. */
4931 for (i = 0, rem = len; i < spd.nr_pages_max && rem; i++) {
4932 spd.pages[i] = alloc_page(GFP_KERNEL);
4933 if (!spd.pages[i])
4934 break;
4935
4936 rem = tracing_fill_pipe_page(rem, iter);
4937
4938 /* Copy the data into the page, so we can start over. */
4939 ret = trace_seq_to_buffer(&iter->seq,
4940 page_address(spd.pages[i]),
4941 trace_seq_used(&iter->seq));
4942 if (ret < 0) {
4943 __free_page(spd.pages[i]);
4944 break;
4945 }
4946 spd.partial[i].offset = 0;
4947 spd.partial[i].len = trace_seq_used(&iter->seq);
4948
4949 trace_seq_init(&iter->seq);
4950 }
4951
4952 trace_access_unlock(iter->cpu_file);
4953 trace_event_read_unlock();
4954 mutex_unlock(&iter->mutex);
4955
4956 spd.nr_pages = i;
4957
4958 if (i)
4959 ret = splice_to_pipe(pipe, &spd);
4960 else
4961 ret = 0;
4962out:
4963 splice_shrink_spd(&spd);
4964 return ret;
4965
4966out_err:
4967 mutex_unlock(&iter->mutex);
4968 goto out;
4969}
4970
4971static ssize_t
4972tracing_entries_read(struct file *filp, char __user *ubuf,
4973 size_t cnt, loff_t *ppos)
4974{
4975 struct inode *inode = file_inode(filp);
4976 struct trace_array *tr = inode->i_private;
4977 int cpu = tracing_get_cpu(inode);
4978 char buf[64];
4979 int r = 0;
4980 ssize_t ret;
4981
4982 mutex_lock(&trace_types_lock);
4983
4984 if (cpu == RING_BUFFER_ALL_CPUS) {
4985 int cpu, buf_size_same;
4986 unsigned long size;
4987
4988 size = 0;
4989 buf_size_same = 1;
4990 /* check if all cpu sizes are same */
4991 for_each_tracing_cpu(cpu) {
4992 /* fill in the size from first enabled cpu */
4993 if (size == 0)
4994 size = per_cpu_ptr(tr->trace_buffer.data, cpu)->entries;
4995 if (size != per_cpu_ptr(tr->trace_buffer.data, cpu)->entries) {
4996 buf_size_same = 0;
4997 break;
4998 }
4999 }
5000
5001 if (buf_size_same) {
5002 if (!ring_buffer_expanded)
5003 r = sprintf(buf, "%lu (expanded: %lu)\n",
5004 size >> 10,
5005 trace_buf_size >> 10);
5006 else
5007 r = sprintf(buf, "%lu\n", size >> 10);
5008 } else
5009 r = sprintf(buf, "X\n");
5010 } else
5011 r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->trace_buffer.data, cpu)->entries >> 10);
5012
5013 mutex_unlock(&trace_types_lock);
5014
5015 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
5016 return ret;
5017}
5018
5019static ssize_t
5020tracing_entries_write(struct file *filp, const char __user *ubuf,
5021 size_t cnt, loff_t *ppos)
5022{
5023 struct inode *inode = file_inode(filp);
5024 struct trace_array *tr = inode->i_private;
5025 unsigned long val;
5026 int ret;
5027
5028 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
5029 if (ret)
5030 return ret;
5031
5032 /* must have at least 1 entry */
5033 if (!val)
5034 return -EINVAL;
5035
5036 /* value is in KB */
5037 val <<= 10;
5038 ret = tracing_resize_ring_buffer(tr, val, tracing_get_cpu(inode));
5039 if (ret < 0)
5040 return ret;
5041
5042 *ppos += cnt;
5043
5044 return cnt;
5045}
5046
5047static ssize_t
5048tracing_total_entries_read(struct file *filp, char __user *ubuf,
5049 size_t cnt, loff_t *ppos)
5050{
5051 struct trace_array *tr = filp->private_data;
5052 char buf[64];
5053 int r, cpu;
5054 unsigned long size = 0, expanded_size = 0;
5055
5056 mutex_lock(&trace_types_lock);
5057 for_each_tracing_cpu(cpu) {
5058 size += per_cpu_ptr(tr->trace_buffer.data, cpu)->entries >> 10;
5059 if (!ring_buffer_expanded)
5060 expanded_size += trace_buf_size >> 10;
5061 }
5062 if (ring_buffer_expanded)
5063 r = sprintf(buf, "%lu\n", size);
5064 else
5065 r = sprintf(buf, "%lu (expanded: %lu)\n", size, expanded_size);
5066 mutex_unlock(&trace_types_lock);
5067
5068 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
5069}
5070
5071static ssize_t
5072tracing_free_buffer_write(struct file *filp, const char __user *ubuf,
5073 size_t cnt, loff_t *ppos)
5074{
5075 /*
5076 * There is no need to read what the user has written, this function
5077 * is just to make sure that there is no error when "echo" is used
5078 */
5079
5080 *ppos += cnt;
5081
5082 return cnt;
5083}
5084
5085static int
5086tracing_free_buffer_release(struct inode *inode, struct file *filp)
5087{
5088 struct trace_array *tr = inode->i_private;
5089
5090 /* disable tracing ? */
5091 if (tr->trace_flags & TRACE_ITER_STOP_ON_FREE)
5092 tracer_tracing_off(tr);
5093 /* resize the ring buffer to 0 */
5094 tracing_resize_ring_buffer(tr, 0, RING_BUFFER_ALL_CPUS);
5095
5096 trace_array_put(tr);
5097
5098 return 0;
5099}
5100
5101static ssize_t
5102tracing_mark_write(struct file *filp, const char __user *ubuf,
5103 size_t cnt, loff_t *fpos)
5104{
5105 unsigned long addr = (unsigned long)ubuf;
5106 struct trace_array *tr = filp->private_data;
5107 struct ring_buffer_event *event;
5108 struct ring_buffer *buffer;
5109 struct print_entry *entry;
5110 unsigned long irq_flags;
5111 struct page *pages[2];
5112 void *map_page[2];
5113 int nr_pages = 1;
5114 ssize_t written;
5115 int offset;
5116 int size;
5117 int len;
5118 int ret;
5119 int i;
5120
5121 if (tracing_disabled)
5122 return -EINVAL;
5123
5124 if (!(tr->trace_flags & TRACE_ITER_MARKERS))
5125 return -EINVAL;
5126
5127 if (cnt > TRACE_BUF_SIZE)
5128 cnt = TRACE_BUF_SIZE;
5129
5130 /*
5131 * Userspace is injecting traces into the kernel trace buffer.
5132 * We want to be as non intrusive as possible.
5133 * To do so, we do not want to allocate any special buffers
5134 * or take any locks, but instead write the userspace data
5135 * straight into the ring buffer.
5136 *
5137 * First we need to pin the userspace buffer into memory,
5138 * which, most likely it is, because it just referenced it.
5139 * But there's no guarantee that it is. By using get_user_pages_fast()
5140 * and kmap_atomic/kunmap_atomic() we can get access to the
5141 * pages directly. We then write the data directly into the
5142 * ring buffer.
5143 */
5144 BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
5145
5146 /* check if we cross pages */
5147 if ((addr & PAGE_MASK) != ((addr + cnt) & PAGE_MASK))
5148 nr_pages = 2;
5149
5150 offset = addr & (PAGE_SIZE - 1);
5151 addr &= PAGE_MASK;
5152
5153 ret = get_user_pages_fast(addr, nr_pages, 0, pages);
5154 if (ret < nr_pages) {
5155 while (--ret >= 0)
5156 put_page(pages[ret]);
5157 written = -EFAULT;
5158 goto out;
5159 }
5160
5161 for (i = 0; i < nr_pages; i++)
5162 map_page[i] = kmap_atomic(pages[i]);
5163
5164 local_save_flags(irq_flags);
5165 size = sizeof(*entry) + cnt + 2; /* possible \n added */
5166 buffer = tr->trace_buffer.buffer;
5167 event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
5168 irq_flags, preempt_count());
5169 if (!event) {
5170 /* Ring buffer disabled, return as if not open for write */
5171 written = -EBADF;
5172 goto out_unlock;
5173 }
5174
5175 entry = ring_buffer_event_data(event);
5176 entry->ip = _THIS_IP_;
5177
5178 if (nr_pages == 2) {
5179 len = PAGE_SIZE - offset;
5180 memcpy(&entry->buf, map_page[0] + offset, len);
5181 memcpy(&entry->buf[len], map_page[1], cnt - len);
5182 } else
5183 memcpy(&entry->buf, map_page[0] + offset, cnt);
5184
5185 if (entry->buf[cnt - 1] != '\n') {
5186 entry->buf[cnt] = '\n';
5187 entry->buf[cnt + 1] = '\0';
5188 } else
5189 entry->buf[cnt] = '\0';
5190
5191 __buffer_unlock_commit(buffer, event);
5192
5193 written = cnt;
5194
5195 *fpos += written;
5196
5197 out_unlock:
5198 for (i = nr_pages - 1; i >= 0; i--) {
5199 kunmap_atomic(map_page[i]);
5200 put_page(pages[i]);
5201 }
5202 out:
5203 return written;
5204}
5205
5206static int tracing_clock_show(struct seq_file *m, void *v)
5207{
5208 struct trace_array *tr = m->private;
5209 int i;
5210
5211 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++)
5212 seq_printf(m,
5213 "%s%s%s%s", i ? " " : "",
5214 i == tr->clock_id ? "[" : "", trace_clocks[i].name,
5215 i == tr->clock_id ? "]" : "");
5216 seq_putc(m, '\n');
5217
5218 return 0;
5219}
5220
5221static int tracing_set_clock(struct trace_array *tr, const char *clockstr)
5222{
5223 int i;
5224
5225 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) {
5226 if (strcmp(trace_clocks[i].name, clockstr) == 0)
5227 break;
5228 }
5229 if (i == ARRAY_SIZE(trace_clocks))
5230 return -EINVAL;
5231
5232 mutex_lock(&trace_types_lock);
5233
5234 tr->clock_id = i;
5235
5236 ring_buffer_set_clock(tr->trace_buffer.buffer, trace_clocks[i].func);
5237
5238 /*
5239 * New clock may not be consistent with the previous clock.
5240 * Reset the buffer so that it doesn't have incomparable timestamps.
5241 */
5242 tracing_reset_online_cpus(&tr->trace_buffer);
5243
5244#ifdef CONFIG_TRACER_MAX_TRACE
5245 if (tr->flags & TRACE_ARRAY_FL_GLOBAL && tr->max_buffer.buffer)
5246 ring_buffer_set_clock(tr->max_buffer.buffer, trace_clocks[i].func);
5247 tracing_reset_online_cpus(&tr->max_buffer);
5248#endif
5249
5250 mutex_unlock(&trace_types_lock);
5251
5252 return 0;
5253}
5254
5255static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf,
5256 size_t cnt, loff_t *fpos)
5257{
5258 struct seq_file *m = filp->private_data;
5259 struct trace_array *tr = m->private;
5260 char buf[64];
5261 const char *clockstr;
5262 int ret;
5263
5264 if (cnt >= sizeof(buf))
5265 return -EINVAL;
5266
5267 if (copy_from_user(&buf, ubuf, cnt))
5268 return -EFAULT;
5269
5270 buf[cnt] = 0;
5271
5272 clockstr = strstrip(buf);
5273
5274 ret = tracing_set_clock(tr, clockstr);
5275 if (ret)
5276 return ret;
5277
5278 *fpos += cnt;
5279
5280 return cnt;
5281}
5282
5283static int tracing_clock_open(struct inode *inode, struct file *file)
5284{
5285 struct trace_array *tr = inode->i_private;
5286 int ret;
5287
5288 if (tracing_disabled)
5289 return -ENODEV;
5290
5291 if (trace_array_get(tr))
5292 return -ENODEV;
5293
5294 ret = single_open(file, tracing_clock_show, inode->i_private);
5295 if (ret < 0)
5296 trace_array_put(tr);
5297
5298 return ret;
5299}
5300
5301struct ftrace_buffer_info {
5302 struct trace_iterator iter;
5303 void *spare;
5304 unsigned int read;
5305};
5306
5307#ifdef CONFIG_TRACER_SNAPSHOT
5308static int tracing_snapshot_open(struct inode *inode, struct file *file)
5309{
5310 struct trace_array *tr = inode->i_private;
5311 struct trace_iterator *iter;
5312 struct seq_file *m;
5313 int ret = 0;
5314
5315 if (trace_array_get(tr) < 0)
5316 return -ENODEV;
5317
5318 if (file->f_mode & FMODE_READ) {
5319 iter = __tracing_open(inode, file, true);
5320 if (IS_ERR(iter))
5321 ret = PTR_ERR(iter);
5322 } else {
5323 /* Writes still need the seq_file to hold the private data */
5324 ret = -ENOMEM;
5325 m = kzalloc(sizeof(*m), GFP_KERNEL);
5326 if (!m)
5327 goto out;
5328 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
5329 if (!iter) {
5330 kfree(m);
5331 goto out;
5332 }
5333 ret = 0;
5334
5335 iter->tr = tr;
5336 iter->trace_buffer = &tr->max_buffer;
5337 iter->cpu_file = tracing_get_cpu(inode);
5338 m->private = iter;
5339 file->private_data = m;
5340 }
5341out:
5342 if (ret < 0)
5343 trace_array_put(tr);
5344
5345 return ret;
5346}
5347
5348static ssize_t
5349tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
5350 loff_t *ppos)
5351{
5352 struct seq_file *m = filp->private_data;
5353 struct trace_iterator *iter = m->private;
5354 struct trace_array *tr = iter->tr;
5355 unsigned long val;
5356 int ret;
5357
5358 ret = tracing_update_buffers();
5359 if (ret < 0)
5360 return ret;
5361
5362 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
5363 if (ret)
5364 return ret;
5365
5366 mutex_lock(&trace_types_lock);
5367
5368 if (tr->current_trace->use_max_tr) {
5369 ret = -EBUSY;
5370 goto out;
5371 }
5372
5373 switch (val) {
5374 case 0:
5375 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
5376 ret = -EINVAL;
5377 break;
5378 }
5379 if (tr->allocated_snapshot)
5380 free_snapshot(tr);
5381 break;
5382 case 1:
5383/* Only allow per-cpu swap if the ring buffer supports it */
5384#ifndef CONFIG_RING_BUFFER_ALLOW_SWAP
5385 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
5386 ret = -EINVAL;
5387 break;
5388 }
5389#endif
5390 if (!tr->allocated_snapshot) {
5391 ret = alloc_snapshot(tr);
5392 if (ret < 0)
5393 break;
5394 }
5395 local_irq_disable();
5396 /* Now, we're going to swap */
5397 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
5398 update_max_tr(tr, current, smp_processor_id());
5399 else
5400 update_max_tr_single(tr, current, iter->cpu_file);
5401 local_irq_enable();
5402 break;
5403 default:
5404 if (tr->allocated_snapshot) {
5405 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
5406 tracing_reset_online_cpus(&tr->max_buffer);
5407 else
5408 tracing_reset(&tr->max_buffer, iter->cpu_file);
5409 }
5410 break;
5411 }
5412
5413 if (ret >= 0) {
5414 *ppos += cnt;
5415 ret = cnt;
5416 }
5417out:
5418 mutex_unlock(&trace_types_lock);
5419 return ret;
5420}
5421
5422static int tracing_snapshot_release(struct inode *inode, struct file *file)
5423{
5424 struct seq_file *m = file->private_data;
5425 int ret;
5426
5427 ret = tracing_release(inode, file);
5428
5429 if (file->f_mode & FMODE_READ)
5430 return ret;
5431
5432 /* If write only, the seq_file is just a stub */
5433 if (m)
5434 kfree(m->private);
5435 kfree(m);
5436
5437 return 0;
5438}
5439
5440static int tracing_buffers_open(struct inode *inode, struct file *filp);
5441static ssize_t tracing_buffers_read(struct file *filp, char __user *ubuf,
5442 size_t count, loff_t *ppos);
5443static int tracing_buffers_release(struct inode *inode, struct file *file);
5444static ssize_t tracing_buffers_splice_read(struct file *file, loff_t *ppos,
5445 struct pipe_inode_info *pipe, size_t len, unsigned int flags);
5446
5447static int snapshot_raw_open(struct inode *inode, struct file *filp)
5448{
5449 struct ftrace_buffer_info *info;
5450 int ret;
5451
5452 ret = tracing_buffers_open(inode, filp);
5453 if (ret < 0)
5454 return ret;
5455
5456 info = filp->private_data;
5457
5458 if (info->iter.trace->use_max_tr) {
5459 tracing_buffers_release(inode, filp);
5460 return -EBUSY;
5461 }
5462
5463 info->iter.snapshot = true;
5464 info->iter.trace_buffer = &info->iter.tr->max_buffer;
5465
5466 return ret;
5467}
5468
5469#endif /* CONFIG_TRACER_SNAPSHOT */
5470
5471
5472static const struct file_operations tracing_thresh_fops = {
5473 .open = tracing_open_generic,
5474 .read = tracing_thresh_read,
5475 .write = tracing_thresh_write,
5476 .llseek = generic_file_llseek,
5477};
5478
5479#ifdef CONFIG_TRACER_MAX_TRACE
5480static const struct file_operations tracing_max_lat_fops = {
5481 .open = tracing_open_generic,
5482 .read = tracing_max_lat_read,
5483 .write = tracing_max_lat_write,
5484 .llseek = generic_file_llseek,
5485};
5486#endif
5487
5488static const struct file_operations set_tracer_fops = {
5489 .open = tracing_open_generic,
5490 .read = tracing_set_trace_read,
5491 .write = tracing_set_trace_write,
5492 .llseek = generic_file_llseek,
5493};
5494
5495static const struct file_operations tracing_pipe_fops = {
5496 .open = tracing_open_pipe,
5497 .poll = tracing_poll_pipe,
5498 .read = tracing_read_pipe,
5499 .splice_read = tracing_splice_read_pipe,
5500 .release = tracing_release_pipe,
5501 .llseek = no_llseek,
5502};
5503
5504static const struct file_operations tracing_entries_fops = {
5505 .open = tracing_open_generic_tr,
5506 .read = tracing_entries_read,
5507 .write = tracing_entries_write,
5508 .llseek = generic_file_llseek,
5509 .release = tracing_release_generic_tr,
5510};
5511
5512static const struct file_operations tracing_total_entries_fops = {
5513 .open = tracing_open_generic_tr,
5514 .read = tracing_total_entries_read,
5515 .llseek = generic_file_llseek,
5516 .release = tracing_release_generic_tr,
5517};
5518
5519static const struct file_operations tracing_free_buffer_fops = {
5520 .open = tracing_open_generic_tr,
5521 .write = tracing_free_buffer_write,
5522 .release = tracing_free_buffer_release,
5523};
5524
5525static const struct file_operations tracing_mark_fops = {
5526 .open = tracing_open_generic_tr,
5527 .write = tracing_mark_write,
5528 .llseek = generic_file_llseek,
5529 .release = tracing_release_generic_tr,
5530};
5531
5532static const struct file_operations trace_clock_fops = {
5533 .open = tracing_clock_open,
5534 .read = seq_read,
5535 .llseek = seq_lseek,
5536 .release = tracing_single_release_tr,
5537 .write = tracing_clock_write,
5538};
5539
5540#ifdef CONFIG_TRACER_SNAPSHOT
5541static const struct file_operations snapshot_fops = {
5542 .open = tracing_snapshot_open,
5543 .read = seq_read,
5544 .write = tracing_snapshot_write,
5545 .llseek = tracing_lseek,
5546 .release = tracing_snapshot_release,
5547};
5548
5549static const struct file_operations snapshot_raw_fops = {
5550 .open = snapshot_raw_open,
5551 .read = tracing_buffers_read,
5552 .release = tracing_buffers_release,
5553 .splice_read = tracing_buffers_splice_read,
5554 .llseek = no_llseek,
5555};
5556
5557#endif /* CONFIG_TRACER_SNAPSHOT */
5558
5559static int tracing_buffers_open(struct inode *inode, struct file *filp)
5560{
5561 struct trace_array *tr = inode->i_private;
5562 struct ftrace_buffer_info *info;
5563 int ret;
5564
5565 if (tracing_disabled)
5566 return -ENODEV;
5567
5568 if (trace_array_get(tr) < 0)
5569 return -ENODEV;
5570
5571 info = kzalloc(sizeof(*info), GFP_KERNEL);
5572 if (!info) {
5573 trace_array_put(tr);
5574 return -ENOMEM;
5575 }
5576
5577 mutex_lock(&trace_types_lock);
5578
5579 info->iter.tr = tr;
5580 info->iter.cpu_file = tracing_get_cpu(inode);
5581 info->iter.trace = tr->current_trace;
5582 info->iter.trace_buffer = &tr->trace_buffer;
5583 info->spare = NULL;
5584 /* Force reading ring buffer for first read */
5585 info->read = (unsigned int)-1;
5586
5587 filp->private_data = info;
5588
5589 tr->current_trace->ref++;
5590
5591 mutex_unlock(&trace_types_lock);
5592
5593 ret = nonseekable_open(inode, filp);
5594 if (ret < 0)
5595 trace_array_put(tr);
5596
5597 return ret;
5598}
5599
5600static unsigned int
5601tracing_buffers_poll(struct file *filp, poll_table *poll_table)
5602{
5603 struct ftrace_buffer_info *info = filp->private_data;
5604 struct trace_iterator *iter = &info->iter;
5605
5606 return trace_poll(iter, filp, poll_table);
5607}
5608
5609static ssize_t
5610tracing_buffers_read(struct file *filp, char __user *ubuf,
5611 size_t count, loff_t *ppos)
5612{
5613 struct ftrace_buffer_info *info = filp->private_data;
5614 struct trace_iterator *iter = &info->iter;
5615 ssize_t ret;
5616 ssize_t size;
5617
5618 if (!count)
5619 return 0;
5620
5621#ifdef CONFIG_TRACER_MAX_TRACE
5622 if (iter->snapshot && iter->tr->current_trace->use_max_tr)
5623 return -EBUSY;
5624#endif
5625
5626 if (!info->spare)
5627 info->spare = ring_buffer_alloc_read_page(iter->trace_buffer->buffer,
5628 iter->cpu_file);
5629 if (!info->spare)
5630 return -ENOMEM;
5631
5632 /* Do we have previous read data to read? */
5633 if (info->read < PAGE_SIZE)
5634 goto read;
5635
5636 again:
5637 trace_access_lock(iter->cpu_file);
5638 ret = ring_buffer_read_page(iter->trace_buffer->buffer,
5639 &info->spare,
5640 count,
5641 iter->cpu_file, 0);
5642 trace_access_unlock(iter->cpu_file);
5643
5644 if (ret < 0) {
5645 if (trace_empty(iter)) {
5646 if ((filp->f_flags & O_NONBLOCK))
5647 return -EAGAIN;
5648
5649 ret = wait_on_pipe(iter, false);
5650 if (ret)
5651 return ret;
5652
5653 goto again;
5654 }
5655 return 0;
5656 }
5657
5658 info->read = 0;
5659 read:
5660 size = PAGE_SIZE - info->read;
5661 if (size > count)
5662 size = count;
5663
5664 ret = copy_to_user(ubuf, info->spare + info->read, size);
5665 if (ret == size)
5666 return -EFAULT;
5667
5668 size -= ret;
5669
5670 *ppos += size;
5671 info->read += size;
5672
5673 return size;
5674}
5675
5676static int tracing_buffers_release(struct inode *inode, struct file *file)
5677{
5678 struct ftrace_buffer_info *info = file->private_data;
5679 struct trace_iterator *iter = &info->iter;
5680
5681 mutex_lock(&trace_types_lock);
5682
5683 iter->tr->current_trace->ref--;
5684
5685 __trace_array_put(iter->tr);
5686
5687 if (info->spare)
5688 ring_buffer_free_read_page(iter->trace_buffer->buffer, info->spare);
5689 kfree(info);
5690
5691 mutex_unlock(&trace_types_lock);
5692
5693 return 0;
5694}
5695
5696struct buffer_ref {
5697 struct ring_buffer *buffer;
5698 void *page;
5699 int ref;
5700};
5701
5702static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
5703 struct pipe_buffer *buf)
5704{
5705 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
5706
5707 if (--ref->ref)
5708 return;
5709
5710 ring_buffer_free_read_page(ref->buffer, ref->page);
5711 kfree(ref);
5712 buf->private = 0;
5713}
5714
5715static void buffer_pipe_buf_get(struct pipe_inode_info *pipe,
5716 struct pipe_buffer *buf)
5717{
5718 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
5719
5720 ref->ref++;
5721}
5722
5723/* Pipe buffer operations for a buffer. */
5724static const struct pipe_buf_operations buffer_pipe_buf_ops = {
5725 .can_merge = 0,
5726 .confirm = generic_pipe_buf_confirm,
5727 .release = buffer_pipe_buf_release,
5728 .steal = generic_pipe_buf_steal,
5729 .get = buffer_pipe_buf_get,
5730};
5731
5732/*
5733 * Callback from splice_to_pipe(), if we need to release some pages
5734 * at the end of the spd in case we error'ed out in filling the pipe.
5735 */
5736static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
5737{
5738 struct buffer_ref *ref =
5739 (struct buffer_ref *)spd->partial[i].private;
5740
5741 if (--ref->ref)
5742 return;
5743
5744 ring_buffer_free_read_page(ref->buffer, ref->page);
5745 kfree(ref);
5746 spd->partial[i].private = 0;
5747}
5748
5749static ssize_t
5750tracing_buffers_splice_read(struct file *file, loff_t *ppos,
5751 struct pipe_inode_info *pipe, size_t len,
5752 unsigned int flags)
5753{
5754 struct ftrace_buffer_info *info = file->private_data;
5755 struct trace_iterator *iter = &info->iter;
5756 struct partial_page partial_def[PIPE_DEF_BUFFERS];
5757 struct page *pages_def[PIPE_DEF_BUFFERS];
5758 struct splice_pipe_desc spd = {
5759 .pages = pages_def,
5760 .partial = partial_def,
5761 .nr_pages_max = PIPE_DEF_BUFFERS,
5762 .flags = flags,
5763 .ops = &buffer_pipe_buf_ops,
5764 .spd_release = buffer_spd_release,
5765 };
5766 struct buffer_ref *ref;
5767 int entries, size, i;
5768 ssize_t ret = 0;
5769
5770#ifdef CONFIG_TRACER_MAX_TRACE
5771 if (iter->snapshot && iter->tr->current_trace->use_max_tr)
5772 return -EBUSY;
5773#endif
5774
5775 if (splice_grow_spd(pipe, &spd))
5776 return -ENOMEM;
5777
5778 if (*ppos & (PAGE_SIZE - 1))
5779 return -EINVAL;
5780
5781 if (len & (PAGE_SIZE - 1)) {
5782 if (len < PAGE_SIZE)
5783 return -EINVAL;
5784 len &= PAGE_MASK;
5785 }
5786
5787 again:
5788 trace_access_lock(iter->cpu_file);
5789 entries = ring_buffer_entries_cpu(iter->trace_buffer->buffer, iter->cpu_file);
5790
5791 for (i = 0; i < spd.nr_pages_max && len && entries; i++, len -= PAGE_SIZE) {
5792 struct page *page;
5793 int r;
5794
5795 ref = kzalloc(sizeof(*ref), GFP_KERNEL);
5796 if (!ref) {
5797 ret = -ENOMEM;
5798 break;
5799 }
5800
5801 ref->ref = 1;
5802 ref->buffer = iter->trace_buffer->buffer;
5803 ref->page = ring_buffer_alloc_read_page(ref->buffer, iter->cpu_file);
5804 if (!ref->page) {
5805 ret = -ENOMEM;
5806 kfree(ref);
5807 break;
5808 }
5809
5810 r = ring_buffer_read_page(ref->buffer, &ref->page,
5811 len, iter->cpu_file, 1);
5812 if (r < 0) {
5813 ring_buffer_free_read_page(ref->buffer, ref->page);
5814 kfree(ref);
5815 break;
5816 }
5817
5818 /*
5819 * zero out any left over data, this is going to
5820 * user land.
5821 */
5822 size = ring_buffer_page_len(ref->page);
5823 if (size < PAGE_SIZE)
5824 memset(ref->page + size, 0, PAGE_SIZE - size);
5825
5826 page = virt_to_page(ref->page);
5827
5828 spd.pages[i] = page;
5829 spd.partial[i].len = PAGE_SIZE;
5830 spd.partial[i].offset = 0;
5831 spd.partial[i].private = (unsigned long)ref;
5832 spd.nr_pages++;
5833 *ppos += PAGE_SIZE;
5834
5835 entries = ring_buffer_entries_cpu(iter->trace_buffer->buffer, iter->cpu_file);
5836 }
5837
5838 trace_access_unlock(iter->cpu_file);
5839 spd.nr_pages = i;
5840
5841 /* did we read anything? */
5842 if (!spd.nr_pages) {
5843 if (ret)
5844 return ret;
5845
5846 if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK))
5847 return -EAGAIN;
5848
5849 ret = wait_on_pipe(iter, true);
5850 if (ret)
5851 return ret;
5852
5853 goto again;
5854 }
5855
5856 ret = splice_to_pipe(pipe, &spd);
5857 splice_shrink_spd(&spd);
5858
5859 return ret;
5860}
5861
5862static const struct file_operations tracing_buffers_fops = {
5863 .open = tracing_buffers_open,
5864 .read = tracing_buffers_read,
5865 .poll = tracing_buffers_poll,
5866 .release = tracing_buffers_release,
5867 .splice_read = tracing_buffers_splice_read,
5868 .llseek = no_llseek,
5869};
5870
5871static ssize_t
5872tracing_stats_read(struct file *filp, char __user *ubuf,
5873 size_t count, loff_t *ppos)
5874{
5875 struct inode *inode = file_inode(filp);
5876 struct trace_array *tr = inode->i_private;
5877 struct trace_buffer *trace_buf = &tr->trace_buffer;
5878 int cpu = tracing_get_cpu(inode);
5879 struct trace_seq *s;
5880 unsigned long cnt;
5881 unsigned long long t;
5882 unsigned long usec_rem;
5883
5884 s = kmalloc(sizeof(*s), GFP_KERNEL);
5885 if (!s)
5886 return -ENOMEM;
5887
5888 trace_seq_init(s);
5889
5890 cnt = ring_buffer_entries_cpu(trace_buf->buffer, cpu);
5891 trace_seq_printf(s, "entries: %ld\n", cnt);
5892
5893 cnt = ring_buffer_overrun_cpu(trace_buf->buffer, cpu);
5894 trace_seq_printf(s, "overrun: %ld\n", cnt);
5895
5896 cnt = ring_buffer_commit_overrun_cpu(trace_buf->buffer, cpu);
5897 trace_seq_printf(s, "commit overrun: %ld\n", cnt);
5898
5899 cnt = ring_buffer_bytes_cpu(trace_buf->buffer, cpu);
5900 trace_seq_printf(s, "bytes: %ld\n", cnt);
5901
5902 if (trace_clocks[tr->clock_id].in_ns) {
5903 /* local or global for trace_clock */
5904 t = ns2usecs(ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
5905 usec_rem = do_div(t, USEC_PER_SEC);
5906 trace_seq_printf(s, "oldest event ts: %5llu.%06lu\n",
5907 t, usec_rem);
5908
5909 t = ns2usecs(ring_buffer_time_stamp(trace_buf->buffer, cpu));
5910 usec_rem = do_div(t, USEC_PER_SEC);
5911 trace_seq_printf(s, "now ts: %5llu.%06lu\n", t, usec_rem);
5912 } else {
5913 /* counter or tsc mode for trace_clock */
5914 trace_seq_printf(s, "oldest event ts: %llu\n",
5915 ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
5916
5917 trace_seq_printf(s, "now ts: %llu\n",
5918 ring_buffer_time_stamp(trace_buf->buffer, cpu));
5919 }
5920
5921 cnt = ring_buffer_dropped_events_cpu(trace_buf->buffer, cpu);
5922 trace_seq_printf(s, "dropped events: %ld\n", cnt);
5923
5924 cnt = ring_buffer_read_events_cpu(trace_buf->buffer, cpu);
5925 trace_seq_printf(s, "read events: %ld\n", cnt);
5926
5927 count = simple_read_from_buffer(ubuf, count, ppos,
5928 s->buffer, trace_seq_used(s));
5929
5930 kfree(s);
5931
5932 return count;
5933}
5934
5935static const struct file_operations tracing_stats_fops = {
5936 .open = tracing_open_generic_tr,
5937 .read = tracing_stats_read,
5938 .llseek = generic_file_llseek,
5939 .release = tracing_release_generic_tr,
5940};
5941
5942#ifdef CONFIG_DYNAMIC_FTRACE
5943
5944int __weak ftrace_arch_read_dyn_info(char *buf, int size)
5945{
5946 return 0;
5947}
5948
5949static ssize_t
5950tracing_read_dyn_info(struct file *filp, char __user *ubuf,
5951 size_t cnt, loff_t *ppos)
5952{
5953 static char ftrace_dyn_info_buffer[1024];
5954 static DEFINE_MUTEX(dyn_info_mutex);
5955 unsigned long *p = filp->private_data;
5956 char *buf = ftrace_dyn_info_buffer;
5957 int size = ARRAY_SIZE(ftrace_dyn_info_buffer);
5958 int r;
5959
5960 mutex_lock(&dyn_info_mutex);
5961 r = sprintf(buf, "%ld ", *p);
5962
5963 r += ftrace_arch_read_dyn_info(buf+r, (size-1)-r);
5964 buf[r++] = '\n';
5965
5966 r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
5967
5968 mutex_unlock(&dyn_info_mutex);
5969
5970 return r;
5971}
5972
5973static const struct file_operations tracing_dyn_info_fops = {
5974 .open = tracing_open_generic,
5975 .read = tracing_read_dyn_info,
5976 .llseek = generic_file_llseek,
5977};
5978#endif /* CONFIG_DYNAMIC_FTRACE */
5979
5980#if defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE)
5981static void
5982ftrace_snapshot(unsigned long ip, unsigned long parent_ip, void **data)
5983{
5984 tracing_snapshot();
5985}
5986
5987static void
5988ftrace_count_snapshot(unsigned long ip, unsigned long parent_ip, void **data)
5989{
5990 unsigned long *count = (long *)data;
5991
5992 if (!*count)
5993 return;
5994
5995 if (*count != -1)
5996 (*count)--;
5997
5998 tracing_snapshot();
5999}
6000
6001static int
6002ftrace_snapshot_print(struct seq_file *m, unsigned long ip,
6003 struct ftrace_probe_ops *ops, void *data)
6004{
6005 long count = (long)data;
6006
6007 seq_printf(m, "%ps:", (void *)ip);
6008
6009 seq_puts(m, "snapshot");
6010
6011 if (count == -1)
6012 seq_puts(m, ":unlimited\n");
6013 else
6014 seq_printf(m, ":count=%ld\n", count);
6015
6016 return 0;
6017}
6018
6019static struct ftrace_probe_ops snapshot_probe_ops = {
6020 .func = ftrace_snapshot,
6021 .print = ftrace_snapshot_print,
6022};
6023
6024static struct ftrace_probe_ops snapshot_count_probe_ops = {
6025 .func = ftrace_count_snapshot,
6026 .print = ftrace_snapshot_print,
6027};
6028
6029static int
6030ftrace_trace_snapshot_callback(struct ftrace_hash *hash,
6031 char *glob, char *cmd, char *param, int enable)
6032{
6033 struct ftrace_probe_ops *ops;
6034 void *count = (void *)-1;
6035 char *number;
6036 int ret;
6037
6038 /* hash funcs only work with set_ftrace_filter */
6039 if (!enable)
6040 return -EINVAL;
6041
6042 ops = param ? &snapshot_count_probe_ops : &snapshot_probe_ops;
6043
6044 if (glob[0] == '!') {
6045 unregister_ftrace_function_probe_func(glob+1, ops);
6046 return 0;
6047 }
6048
6049 if (!param)
6050 goto out_reg;
6051
6052 number = strsep(¶m, ":");
6053
6054 if (!strlen(number))
6055 goto out_reg;
6056
6057 /*
6058 * We use the callback data field (which is a pointer)
6059 * as our counter.
6060 */
6061 ret = kstrtoul(number, 0, (unsigned long *)&count);
6062 if (ret)
6063 return ret;
6064
6065 out_reg:
6066 ret = register_ftrace_function_probe(glob, ops, count);
6067
6068 if (ret >= 0)
6069 alloc_snapshot(&global_trace);
6070
6071 return ret < 0 ? ret : 0;
6072}
6073
6074static struct ftrace_func_command ftrace_snapshot_cmd = {
6075 .name = "snapshot",
6076 .func = ftrace_trace_snapshot_callback,
6077};
6078
6079static __init int register_snapshot_cmd(void)
6080{
6081 return register_ftrace_command(&ftrace_snapshot_cmd);
6082}
6083#else
6084static inline __init int register_snapshot_cmd(void) { return 0; }
6085#endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
6086
6087static struct dentry *tracing_get_dentry(struct trace_array *tr)
6088{
6089 if (WARN_ON(!tr->dir))
6090 return ERR_PTR(-ENODEV);
6091
6092 /* Top directory uses NULL as the parent */
6093 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
6094 return NULL;
6095
6096 /* All sub buffers have a descriptor */
6097 return tr->dir;
6098}
6099
6100static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu)
6101{
6102 struct dentry *d_tracer;
6103
6104 if (tr->percpu_dir)
6105 return tr->percpu_dir;
6106
6107 d_tracer = tracing_get_dentry(tr);
6108 if (IS_ERR(d_tracer))
6109 return NULL;
6110
6111 tr->percpu_dir = tracefs_create_dir("per_cpu", d_tracer);
6112
6113 WARN_ONCE(!tr->percpu_dir,
6114 "Could not create tracefs directory 'per_cpu/%d'\n", cpu);
6115
6116 return tr->percpu_dir;
6117}
6118
6119static struct dentry *
6120trace_create_cpu_file(const char *name, umode_t mode, struct dentry *parent,
6121 void *data, long cpu, const struct file_operations *fops)
6122{
6123 struct dentry *ret = trace_create_file(name, mode, parent, data, fops);
6124
6125 if (ret) /* See tracing_get_cpu() */
6126 d_inode(ret)->i_cdev = (void *)(cpu + 1);
6127 return ret;
6128}
6129
6130static void
6131tracing_init_tracefs_percpu(struct trace_array *tr, long cpu)
6132{
6133 struct dentry *d_percpu = tracing_dentry_percpu(tr, cpu);
6134 struct dentry *d_cpu;
6135 char cpu_dir[30]; /* 30 characters should be more than enough */
6136
6137 if (!d_percpu)
6138 return;
6139
6140 snprintf(cpu_dir, 30, "cpu%ld", cpu);
6141 d_cpu = tracefs_create_dir(cpu_dir, d_percpu);
6142 if (!d_cpu) {
6143 pr_warn("Could not create tracefs '%s' entry\n", cpu_dir);
6144 return;
6145 }
6146
6147 /* per cpu trace_pipe */
6148 trace_create_cpu_file("trace_pipe", 0444, d_cpu,
6149 tr, cpu, &tracing_pipe_fops);
6150
6151 /* per cpu trace */
6152 trace_create_cpu_file("trace", 0644, d_cpu,
6153 tr, cpu, &tracing_fops);
6154
6155 trace_create_cpu_file("trace_pipe_raw", 0444, d_cpu,
6156 tr, cpu, &tracing_buffers_fops);
6157
6158 trace_create_cpu_file("stats", 0444, d_cpu,
6159 tr, cpu, &tracing_stats_fops);
6160
6161 trace_create_cpu_file("buffer_size_kb", 0444, d_cpu,
6162 tr, cpu, &tracing_entries_fops);
6163
6164#ifdef CONFIG_TRACER_SNAPSHOT
6165 trace_create_cpu_file("snapshot", 0644, d_cpu,
6166 tr, cpu, &snapshot_fops);
6167
6168 trace_create_cpu_file("snapshot_raw", 0444, d_cpu,
6169 tr, cpu, &snapshot_raw_fops);
6170#endif
6171}
6172
6173#ifdef CONFIG_FTRACE_SELFTEST
6174/* Let selftest have access to static functions in this file */
6175#include "trace_selftest.c"
6176#endif
6177
6178static ssize_t
6179trace_options_read(struct file *filp, char __user *ubuf, size_t cnt,
6180 loff_t *ppos)
6181{
6182 struct trace_option_dentry *topt = filp->private_data;
6183 char *buf;
6184
6185 if (topt->flags->val & topt->opt->bit)
6186 buf = "1\n";
6187 else
6188 buf = "0\n";
6189
6190 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
6191}
6192
6193static ssize_t
6194trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt,
6195 loff_t *ppos)
6196{
6197 struct trace_option_dentry *topt = filp->private_data;
6198 unsigned long val;
6199 int ret;
6200
6201 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6202 if (ret)
6203 return ret;
6204
6205 if (val != 0 && val != 1)
6206 return -EINVAL;
6207
6208 if (!!(topt->flags->val & topt->opt->bit) != val) {
6209 mutex_lock(&trace_types_lock);
6210 ret = __set_tracer_option(topt->tr, topt->flags,
6211 topt->opt, !val);
6212 mutex_unlock(&trace_types_lock);
6213 if (ret)
6214 return ret;
6215 }
6216
6217 *ppos += cnt;
6218
6219 return cnt;
6220}
6221
6222
6223static const struct file_operations trace_options_fops = {
6224 .open = tracing_open_generic,
6225 .read = trace_options_read,
6226 .write = trace_options_write,
6227 .llseek = generic_file_llseek,
6228};
6229
6230/*
6231 * In order to pass in both the trace_array descriptor as well as the index
6232 * to the flag that the trace option file represents, the trace_array
6233 * has a character array of trace_flags_index[], which holds the index
6234 * of the bit for the flag it represents. index[0] == 0, index[1] == 1, etc.
6235 * The address of this character array is passed to the flag option file
6236 * read/write callbacks.
6237 *
6238 * In order to extract both the index and the trace_array descriptor,
6239 * get_tr_index() uses the following algorithm.
6240 *
6241 * idx = *ptr;
6242 *
6243 * As the pointer itself contains the address of the index (remember
6244 * index[1] == 1).
6245 *
6246 * Then to get the trace_array descriptor, by subtracting that index
6247 * from the ptr, we get to the start of the index itself.
6248 *
6249 * ptr - idx == &index[0]
6250 *
6251 * Then a simple container_of() from that pointer gets us to the
6252 * trace_array descriptor.
6253 */
6254static void get_tr_index(void *data, struct trace_array **ptr,
6255 unsigned int *pindex)
6256{
6257 *pindex = *(unsigned char *)data;
6258
6259 *ptr = container_of(data - *pindex, struct trace_array,
6260 trace_flags_index);
6261}
6262
6263static ssize_t
6264trace_options_core_read(struct file *filp, char __user *ubuf, size_t cnt,
6265 loff_t *ppos)
6266{
6267 void *tr_index = filp->private_data;
6268 struct trace_array *tr;
6269 unsigned int index;
6270 char *buf;
6271
6272 get_tr_index(tr_index, &tr, &index);
6273
6274 if (tr->trace_flags & (1 << index))
6275 buf = "1\n";
6276 else
6277 buf = "0\n";
6278
6279 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
6280}
6281
6282static ssize_t
6283trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
6284 loff_t *ppos)
6285{
6286 void *tr_index = filp->private_data;
6287 struct trace_array *tr;
6288 unsigned int index;
6289 unsigned long val;
6290 int ret;
6291
6292 get_tr_index(tr_index, &tr, &index);
6293
6294 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6295 if (ret)
6296 return ret;
6297
6298 if (val != 0 && val != 1)
6299 return -EINVAL;
6300
6301 mutex_lock(&trace_types_lock);
6302 ret = set_tracer_flag(tr, 1 << index, val);
6303 mutex_unlock(&trace_types_lock);
6304
6305 if (ret < 0)
6306 return ret;
6307
6308 *ppos += cnt;
6309
6310 return cnt;
6311}
6312
6313static const struct file_operations trace_options_core_fops = {
6314 .open = tracing_open_generic,
6315 .read = trace_options_core_read,
6316 .write = trace_options_core_write,
6317 .llseek = generic_file_llseek,
6318};
6319
6320struct dentry *trace_create_file(const char *name,
6321 umode_t mode,
6322 struct dentry *parent,
6323 void *data,
6324 const struct file_operations *fops)
6325{
6326 struct dentry *ret;
6327
6328 ret = tracefs_create_file(name, mode, parent, data, fops);
6329 if (!ret)
6330 pr_warn("Could not create tracefs '%s' entry\n", name);
6331
6332 return ret;
6333}
6334
6335
6336static struct dentry *trace_options_init_dentry(struct trace_array *tr)
6337{
6338 struct dentry *d_tracer;
6339
6340 if (tr->options)
6341 return tr->options;
6342
6343 d_tracer = tracing_get_dentry(tr);
6344 if (IS_ERR(d_tracer))
6345 return NULL;
6346
6347 tr->options = tracefs_create_dir("options", d_tracer);
6348 if (!tr->options) {
6349 pr_warn("Could not create tracefs directory 'options'\n");
6350 return NULL;
6351 }
6352
6353 return tr->options;
6354}
6355
6356static void
6357create_trace_option_file(struct trace_array *tr,
6358 struct trace_option_dentry *topt,
6359 struct tracer_flags *flags,
6360 struct tracer_opt *opt)
6361{
6362 struct dentry *t_options;
6363
6364 t_options = trace_options_init_dentry(tr);
6365 if (!t_options)
6366 return;
6367
6368 topt->flags = flags;
6369 topt->opt = opt;
6370 topt->tr = tr;
6371
6372 topt->entry = trace_create_file(opt->name, 0644, t_options, topt,
6373 &trace_options_fops);
6374
6375}
6376
6377static void
6378create_trace_option_files(struct trace_array *tr, struct tracer *tracer)
6379{
6380 struct trace_option_dentry *topts;
6381 struct trace_options *tr_topts;
6382 struct tracer_flags *flags;
6383 struct tracer_opt *opts;
6384 int cnt;
6385 int i;
6386
6387 if (!tracer)
6388 return;
6389
6390 flags = tracer->flags;
6391
6392 if (!flags || !flags->opts)
6393 return;
6394
6395 /*
6396 * If this is an instance, only create flags for tracers
6397 * the instance may have.
6398 */
6399 if (!trace_ok_for_array(tracer, tr))
6400 return;
6401
6402 for (i = 0; i < tr->nr_topts; i++) {
6403 /* Make sure there's no duplicate flags. */
6404 if (WARN_ON_ONCE(tr->topts[i].tracer->flags == tracer->flags))
6405 return;
6406 }
6407
6408 opts = flags->opts;
6409
6410 for (cnt = 0; opts[cnt].name; cnt++)
6411 ;
6412
6413 topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL);
6414 if (!topts)
6415 return;
6416
6417 tr_topts = krealloc(tr->topts, sizeof(*tr->topts) * (tr->nr_topts + 1),
6418 GFP_KERNEL);
6419 if (!tr_topts) {
6420 kfree(topts);
6421 return;
6422 }
6423
6424 tr->topts = tr_topts;
6425 tr->topts[tr->nr_topts].tracer = tracer;
6426 tr->topts[tr->nr_topts].topts = topts;
6427 tr->nr_topts++;
6428
6429 for (cnt = 0; opts[cnt].name; cnt++) {
6430 create_trace_option_file(tr, &topts[cnt], flags,
6431 &opts[cnt]);
6432 WARN_ONCE(topts[cnt].entry == NULL,
6433 "Failed to create trace option: %s",
6434 opts[cnt].name);
6435 }
6436}
6437
6438static struct dentry *
6439create_trace_option_core_file(struct trace_array *tr,
6440 const char *option, long index)
6441{
6442 struct dentry *t_options;
6443
6444 t_options = trace_options_init_dentry(tr);
6445 if (!t_options)
6446 return NULL;
6447
6448 return trace_create_file(option, 0644, t_options,
6449 (void *)&tr->trace_flags_index[index],
6450 &trace_options_core_fops);
6451}
6452
6453static void create_trace_options_dir(struct trace_array *tr)
6454{
6455 struct dentry *t_options;
6456 bool top_level = tr == &global_trace;
6457 int i;
6458
6459 t_options = trace_options_init_dentry(tr);
6460 if (!t_options)
6461 return;
6462
6463 for (i = 0; trace_options[i]; i++) {
6464 if (top_level ||
6465 !((1 << i) & TOP_LEVEL_TRACE_FLAGS))
6466 create_trace_option_core_file(tr, trace_options[i], i);
6467 }
6468}
6469
6470static ssize_t
6471rb_simple_read(struct file *filp, char __user *ubuf,
6472 size_t cnt, loff_t *ppos)
6473{
6474 struct trace_array *tr = filp->private_data;
6475 char buf[64];
6476 int r;
6477
6478 r = tracer_tracing_is_on(tr);
6479 r = sprintf(buf, "%d\n", r);
6480
6481 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6482}
6483
6484static ssize_t
6485rb_simple_write(struct file *filp, const char __user *ubuf,
6486 size_t cnt, loff_t *ppos)
6487{
6488 struct trace_array *tr = filp->private_data;
6489 struct ring_buffer *buffer = tr->trace_buffer.buffer;
6490 unsigned long val;
6491 int ret;
6492
6493 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6494 if (ret)
6495 return ret;
6496
6497 if (buffer) {
6498 mutex_lock(&trace_types_lock);
6499 if (val) {
6500 tracer_tracing_on(tr);
6501 if (tr->current_trace->start)
6502 tr->current_trace->start(tr);
6503 } else {
6504 tracer_tracing_off(tr);
6505 if (tr->current_trace->stop)
6506 tr->current_trace->stop(tr);
6507 }
6508 mutex_unlock(&trace_types_lock);
6509 }
6510
6511 (*ppos)++;
6512
6513 return cnt;
6514}
6515
6516static const struct file_operations rb_simple_fops = {
6517 .open = tracing_open_generic_tr,
6518 .read = rb_simple_read,
6519 .write = rb_simple_write,
6520 .release = tracing_release_generic_tr,
6521 .llseek = default_llseek,
6522};
6523
6524struct dentry *trace_instance_dir;
6525
6526static void
6527init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer);
6528
6529static int
6530allocate_trace_buffer(struct trace_array *tr, struct trace_buffer *buf, int size)
6531{
6532 enum ring_buffer_flags rb_flags;
6533
6534 rb_flags = tr->trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0;
6535
6536 buf->tr = tr;
6537
6538 buf->buffer = ring_buffer_alloc(size, rb_flags);
6539 if (!buf->buffer)
6540 return -ENOMEM;
6541
6542 buf->data = alloc_percpu(struct trace_array_cpu);
6543 if (!buf->data) {
6544 ring_buffer_free(buf->buffer);
6545 return -ENOMEM;
6546 }
6547
6548 /* Allocate the first page for all buffers */
6549 set_buffer_entries(&tr->trace_buffer,
6550 ring_buffer_size(tr->trace_buffer.buffer, 0));
6551
6552 return 0;
6553}
6554
6555static int allocate_trace_buffers(struct trace_array *tr, int size)
6556{
6557 int ret;
6558
6559 ret = allocate_trace_buffer(tr, &tr->trace_buffer, size);
6560 if (ret)
6561 return ret;
6562
6563#ifdef CONFIG_TRACER_MAX_TRACE
6564 ret = allocate_trace_buffer(tr, &tr->max_buffer,
6565 allocate_snapshot ? size : 1);
6566 if (WARN_ON(ret)) {
6567 ring_buffer_free(tr->trace_buffer.buffer);
6568 free_percpu(tr->trace_buffer.data);
6569 return -ENOMEM;
6570 }
6571 tr->allocated_snapshot = allocate_snapshot;
6572
6573 /*
6574 * Only the top level trace array gets its snapshot allocated
6575 * from the kernel command line.
6576 */
6577 allocate_snapshot = false;
6578#endif
6579 return 0;
6580}
6581
6582static void free_trace_buffer(struct trace_buffer *buf)
6583{
6584 if (buf->buffer) {
6585 ring_buffer_free(buf->buffer);
6586 buf->buffer = NULL;
6587 free_percpu(buf->data);
6588 buf->data = NULL;
6589 }
6590}
6591
6592static void free_trace_buffers(struct trace_array *tr)
6593{
6594 if (!tr)
6595 return;
6596
6597 free_trace_buffer(&tr->trace_buffer);
6598
6599#ifdef CONFIG_TRACER_MAX_TRACE
6600 free_trace_buffer(&tr->max_buffer);
6601#endif
6602}
6603
6604static void init_trace_flags_index(struct trace_array *tr)
6605{
6606 int i;
6607
6608 /* Used by the trace options files */
6609 for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++)
6610 tr->trace_flags_index[i] = i;
6611}
6612
6613static void __update_tracer_options(struct trace_array *tr)
6614{
6615 struct tracer *t;
6616
6617 for (t = trace_types; t; t = t->next)
6618 add_tracer_options(tr, t);
6619}
6620
6621static void update_tracer_options(struct trace_array *tr)
6622{
6623 mutex_lock(&trace_types_lock);
6624 __update_tracer_options(tr);
6625 mutex_unlock(&trace_types_lock);
6626}
6627
6628static int instance_mkdir(const char *name)
6629{
6630 struct trace_array *tr;
6631 int ret;
6632
6633 mutex_lock(&trace_types_lock);
6634
6635 ret = -EEXIST;
6636 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6637 if (tr->name && strcmp(tr->name, name) == 0)
6638 goto out_unlock;
6639 }
6640
6641 ret = -ENOMEM;
6642 tr = kzalloc(sizeof(*tr), GFP_KERNEL);
6643 if (!tr)
6644 goto out_unlock;
6645
6646 tr->name = kstrdup(name, GFP_KERNEL);
6647 if (!tr->name)
6648 goto out_free_tr;
6649
6650 if (!alloc_cpumask_var(&tr->tracing_cpumask, GFP_KERNEL))
6651 goto out_free_tr;
6652
6653 tr->trace_flags = global_trace.trace_flags;
6654
6655 cpumask_copy(tr->tracing_cpumask, cpu_all_mask);
6656
6657 raw_spin_lock_init(&tr->start_lock);
6658
6659 tr->max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
6660
6661 tr->current_trace = &nop_trace;
6662
6663 INIT_LIST_HEAD(&tr->systems);
6664 INIT_LIST_HEAD(&tr->events);
6665
6666 if (allocate_trace_buffers(tr, trace_buf_size) < 0)
6667 goto out_free_tr;
6668
6669 tr->dir = tracefs_create_dir(name, trace_instance_dir);
6670 if (!tr->dir)
6671 goto out_free_tr;
6672
6673 ret = event_trace_add_tracer(tr->dir, tr);
6674 if (ret) {
6675 tracefs_remove_recursive(tr->dir);
6676 goto out_free_tr;
6677 }
6678
6679 init_tracer_tracefs(tr, tr->dir);
6680 init_trace_flags_index(tr);
6681 __update_tracer_options(tr);
6682
6683 list_add(&tr->list, &ftrace_trace_arrays);
6684
6685 mutex_unlock(&trace_types_lock);
6686
6687 return 0;
6688
6689 out_free_tr:
6690 free_trace_buffers(tr);
6691 free_cpumask_var(tr->tracing_cpumask);
6692 kfree(tr->name);
6693 kfree(tr);
6694
6695 out_unlock:
6696 mutex_unlock(&trace_types_lock);
6697
6698 return ret;
6699
6700}
6701
6702static int instance_rmdir(const char *name)
6703{
6704 struct trace_array *tr;
6705 int found = 0;
6706 int ret;
6707 int i;
6708
6709 mutex_lock(&trace_types_lock);
6710
6711 ret = -ENODEV;
6712 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6713 if (tr->name && strcmp(tr->name, name) == 0) {
6714 found = 1;
6715 break;
6716 }
6717 }
6718 if (!found)
6719 goto out_unlock;
6720
6721 ret = -EBUSY;
6722 if (tr->ref || (tr->current_trace && tr->current_trace->ref))
6723 goto out_unlock;
6724
6725 list_del(&tr->list);
6726
6727 tracing_set_nop(tr);
6728 event_trace_del_tracer(tr);
6729 ftrace_destroy_function_files(tr);
6730 tracefs_remove_recursive(tr->dir);
6731 free_trace_buffers(tr);
6732
6733 for (i = 0; i < tr->nr_topts; i++) {
6734 kfree(tr->topts[i].topts);
6735 }
6736 kfree(tr->topts);
6737
6738 kfree(tr->name);
6739 kfree(tr);
6740
6741 ret = 0;
6742
6743 out_unlock:
6744 mutex_unlock(&trace_types_lock);
6745
6746 return ret;
6747}
6748
6749static __init void create_trace_instances(struct dentry *d_tracer)
6750{
6751 trace_instance_dir = tracefs_create_instance_dir("instances", d_tracer,
6752 instance_mkdir,
6753 instance_rmdir);
6754 if (WARN_ON(!trace_instance_dir))
6755 return;
6756}
6757
6758static void
6759init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
6760{
6761 int cpu;
6762
6763 trace_create_file("available_tracers", 0444, d_tracer,
6764 tr, &show_traces_fops);
6765
6766 trace_create_file("current_tracer", 0644, d_tracer,
6767 tr, &set_tracer_fops);
6768
6769 trace_create_file("tracing_cpumask", 0644, d_tracer,
6770 tr, &tracing_cpumask_fops);
6771
6772 trace_create_file("trace_options", 0644, d_tracer,
6773 tr, &tracing_iter_fops);
6774
6775 trace_create_file("trace", 0644, d_tracer,
6776 tr, &tracing_fops);
6777
6778 trace_create_file("trace_pipe", 0444, d_tracer,
6779 tr, &tracing_pipe_fops);
6780
6781 trace_create_file("buffer_size_kb", 0644, d_tracer,
6782 tr, &tracing_entries_fops);
6783
6784 trace_create_file("buffer_total_size_kb", 0444, d_tracer,
6785 tr, &tracing_total_entries_fops);
6786
6787 trace_create_file("free_buffer", 0200, d_tracer,
6788 tr, &tracing_free_buffer_fops);
6789
6790 trace_create_file("trace_marker", 0220, d_tracer,
6791 tr, &tracing_mark_fops);
6792
6793 trace_create_file("trace_clock", 0644, d_tracer, tr,
6794 &trace_clock_fops);
6795
6796 trace_create_file("tracing_on", 0644, d_tracer,
6797 tr, &rb_simple_fops);
6798
6799 create_trace_options_dir(tr);
6800
6801#ifdef CONFIG_TRACER_MAX_TRACE
6802 trace_create_file("tracing_max_latency", 0644, d_tracer,
6803 &tr->max_latency, &tracing_max_lat_fops);
6804#endif
6805
6806 if (ftrace_create_function_files(tr, d_tracer))
6807 WARN(1, "Could not allocate function filter files");
6808
6809#ifdef CONFIG_TRACER_SNAPSHOT
6810 trace_create_file("snapshot", 0644, d_tracer,
6811 tr, &snapshot_fops);
6812#endif
6813
6814 for_each_tracing_cpu(cpu)
6815 tracing_init_tracefs_percpu(tr, cpu);
6816
6817}
6818
6819static struct vfsmount *trace_automount(void *ingore)
6820{
6821 struct vfsmount *mnt;
6822 struct file_system_type *type;
6823
6824 /*
6825 * To maintain backward compatibility for tools that mount
6826 * debugfs to get to the tracing facility, tracefs is automatically
6827 * mounted to the debugfs/tracing directory.
6828 */
6829 type = get_fs_type("tracefs");
6830 if (!type)
6831 return NULL;
6832 mnt = vfs_kern_mount(type, 0, "tracefs", NULL);
6833 put_filesystem(type);
6834 if (IS_ERR(mnt))
6835 return NULL;
6836 mntget(mnt);
6837
6838 return mnt;
6839}
6840
6841/**
6842 * tracing_init_dentry - initialize top level trace array
6843 *
6844 * This is called when creating files or directories in the tracing
6845 * directory. It is called via fs_initcall() by any of the boot up code
6846 * and expects to return the dentry of the top level tracing directory.
6847 */
6848struct dentry *tracing_init_dentry(void)
6849{
6850 struct trace_array *tr = &global_trace;
6851
6852 /* The top level trace array uses NULL as parent */
6853 if (tr->dir)
6854 return NULL;
6855
6856 if (WARN_ON(!tracefs_initialized()) ||
6857 (IS_ENABLED(CONFIG_DEBUG_FS) &&
6858 WARN_ON(!debugfs_initialized())))
6859 return ERR_PTR(-ENODEV);
6860
6861 /*
6862 * As there may still be users that expect the tracing
6863 * files to exist in debugfs/tracing, we must automount
6864 * the tracefs file system there, so older tools still
6865 * work with the newer kerenl.
6866 */
6867 tr->dir = debugfs_create_automount("tracing", NULL,
6868 trace_automount, NULL);
6869 if (!tr->dir) {
6870 pr_warn_once("Could not create debugfs directory 'tracing'\n");
6871 return ERR_PTR(-ENOMEM);
6872 }
6873
6874 return NULL;
6875}
6876
6877extern struct trace_enum_map *__start_ftrace_enum_maps[];
6878extern struct trace_enum_map *__stop_ftrace_enum_maps[];
6879
6880static void __init trace_enum_init(void)
6881{
6882 int len;
6883
6884 len = __stop_ftrace_enum_maps - __start_ftrace_enum_maps;
6885 trace_insert_enum_map(NULL, __start_ftrace_enum_maps, len);
6886}
6887
6888#ifdef CONFIG_MODULES
6889static void trace_module_add_enums(struct module *mod)
6890{
6891 if (!mod->num_trace_enums)
6892 return;
6893
6894 /*
6895 * Modules with bad taint do not have events created, do
6896 * not bother with enums either.
6897 */
6898 if (trace_module_has_bad_taint(mod))
6899 return;
6900
6901 trace_insert_enum_map(mod, mod->trace_enums, mod->num_trace_enums);
6902}
6903
6904#ifdef CONFIG_TRACE_ENUM_MAP_FILE
6905static void trace_module_remove_enums(struct module *mod)
6906{
6907 union trace_enum_map_item *map;
6908 union trace_enum_map_item **last = &trace_enum_maps;
6909
6910 if (!mod->num_trace_enums)
6911 return;
6912
6913 mutex_lock(&trace_enum_mutex);
6914
6915 map = trace_enum_maps;
6916
6917 while (map) {
6918 if (map->head.mod == mod)
6919 break;
6920 map = trace_enum_jmp_to_tail(map);
6921 last = &map->tail.next;
6922 map = map->tail.next;
6923 }
6924 if (!map)
6925 goto out;
6926
6927 *last = trace_enum_jmp_to_tail(map)->tail.next;
6928 kfree(map);
6929 out:
6930 mutex_unlock(&trace_enum_mutex);
6931}
6932#else
6933static inline void trace_module_remove_enums(struct module *mod) { }
6934#endif /* CONFIG_TRACE_ENUM_MAP_FILE */
6935
6936static int trace_module_notify(struct notifier_block *self,
6937 unsigned long val, void *data)
6938{
6939 struct module *mod = data;
6940
6941 switch (val) {
6942 case MODULE_STATE_COMING:
6943 trace_module_add_enums(mod);
6944 break;
6945 case MODULE_STATE_GOING:
6946 trace_module_remove_enums(mod);
6947 break;
6948 }
6949
6950 return 0;
6951}
6952
6953static struct notifier_block trace_module_nb = {
6954 .notifier_call = trace_module_notify,
6955 .priority = 0,
6956};
6957#endif /* CONFIG_MODULES */
6958
6959static __init int tracer_init_tracefs(void)
6960{
6961 struct dentry *d_tracer;
6962
6963 trace_access_lock_init();
6964
6965 d_tracer = tracing_init_dentry();
6966 if (IS_ERR(d_tracer))
6967 return 0;
6968
6969 init_tracer_tracefs(&global_trace, d_tracer);
6970
6971 trace_create_file("tracing_thresh", 0644, d_tracer,
6972 &global_trace, &tracing_thresh_fops);
6973
6974 trace_create_file("README", 0444, d_tracer,
6975 NULL, &tracing_readme_fops);
6976
6977 trace_create_file("saved_cmdlines", 0444, d_tracer,
6978 NULL, &tracing_saved_cmdlines_fops);
6979
6980 trace_create_file("saved_cmdlines_size", 0644, d_tracer,
6981 NULL, &tracing_saved_cmdlines_size_fops);
6982
6983 trace_enum_init();
6984
6985 trace_create_enum_file(d_tracer);
6986
6987#ifdef CONFIG_MODULES
6988 register_module_notifier(&trace_module_nb);
6989#endif
6990
6991#ifdef CONFIG_DYNAMIC_FTRACE
6992 trace_create_file("dyn_ftrace_total_info", 0444, d_tracer,
6993 &ftrace_update_tot_cnt, &tracing_dyn_info_fops);
6994#endif
6995
6996 create_trace_instances(d_tracer);
6997
6998 update_tracer_options(&global_trace);
6999
7000 return 0;
7001}
7002
7003static int trace_panic_handler(struct notifier_block *this,
7004 unsigned long event, void *unused)
7005{
7006 if (ftrace_dump_on_oops)
7007 ftrace_dump(ftrace_dump_on_oops);
7008 return NOTIFY_OK;
7009}
7010
7011static struct notifier_block trace_panic_notifier = {
7012 .notifier_call = trace_panic_handler,
7013 .next = NULL,
7014 .priority = 150 /* priority: INT_MAX >= x >= 0 */
7015};
7016
7017static int trace_die_handler(struct notifier_block *self,
7018 unsigned long val,
7019 void *data)
7020{
7021 switch (val) {
7022 case DIE_OOPS:
7023 if (ftrace_dump_on_oops)
7024 ftrace_dump(ftrace_dump_on_oops);
7025 break;
7026 default:
7027 break;
7028 }
7029 return NOTIFY_OK;
7030}
7031
7032static struct notifier_block trace_die_notifier = {
7033 .notifier_call = trace_die_handler,
7034 .priority = 200
7035};
7036
7037/*
7038 * printk is set to max of 1024, we really don't need it that big.
7039 * Nothing should be printing 1000 characters anyway.
7040 */
7041#define TRACE_MAX_PRINT 1000
7042
7043/*
7044 * Define here KERN_TRACE so that we have one place to modify
7045 * it if we decide to change what log level the ftrace dump
7046 * should be at.
7047 */
7048#define KERN_TRACE KERN_EMERG
7049
7050void
7051trace_printk_seq(struct trace_seq *s)
7052{
7053 /* Probably should print a warning here. */
7054 if (s->seq.len >= TRACE_MAX_PRINT)
7055 s->seq.len = TRACE_MAX_PRINT;
7056
7057 /*
7058 * More paranoid code. Although the buffer size is set to
7059 * PAGE_SIZE, and TRACE_MAX_PRINT is 1000, this is just
7060 * an extra layer of protection.
7061 */
7062 if (WARN_ON_ONCE(s->seq.len >= s->seq.size))
7063 s->seq.len = s->seq.size - 1;
7064
7065 /* should be zero ended, but we are paranoid. */
7066 s->buffer[s->seq.len] = 0;
7067
7068 printk(KERN_TRACE "%s", s->buffer);
7069
7070 trace_seq_init(s);
7071}
7072
7073void trace_init_global_iter(struct trace_iterator *iter)
7074{
7075 iter->tr = &global_trace;
7076 iter->trace = iter->tr->current_trace;
7077 iter->cpu_file = RING_BUFFER_ALL_CPUS;
7078 iter->trace_buffer = &global_trace.trace_buffer;
7079
7080 if (iter->trace && iter->trace->open)
7081 iter->trace->open(iter);
7082
7083 /* Annotate start of buffers if we had overruns */
7084 if (ring_buffer_overruns(iter->trace_buffer->buffer))
7085 iter->iter_flags |= TRACE_FILE_ANNOTATE;
7086
7087 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
7088 if (trace_clocks[iter->tr->clock_id].in_ns)
7089 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
7090}
7091
7092void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
7093{
7094 /* use static because iter can be a bit big for the stack */
7095 static struct trace_iterator iter;
7096 static atomic_t dump_running;
7097 struct trace_array *tr = &global_trace;
7098 unsigned int old_userobj;
7099 unsigned long flags;
7100 int cnt = 0, cpu;
7101
7102 /* Only allow one dump user at a time. */
7103 if (atomic_inc_return(&dump_running) != 1) {
7104 atomic_dec(&dump_running);
7105 return;
7106 }
7107
7108 /*
7109 * Always turn off tracing when we dump.
7110 * We don't need to show trace output of what happens
7111 * between multiple crashes.
7112 *
7113 * If the user does a sysrq-z, then they can re-enable
7114 * tracing with echo 1 > tracing_on.
7115 */
7116 tracing_off();
7117
7118 local_irq_save(flags);
7119
7120 /* Simulate the iterator */
7121 trace_init_global_iter(&iter);
7122
7123 for_each_tracing_cpu(cpu) {
7124 atomic_inc(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
7125 }
7126
7127 old_userobj = tr->trace_flags & TRACE_ITER_SYM_USEROBJ;
7128
7129 /* don't look at user memory in panic mode */
7130 tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
7131
7132 switch (oops_dump_mode) {
7133 case DUMP_ALL:
7134 iter.cpu_file = RING_BUFFER_ALL_CPUS;
7135 break;
7136 case DUMP_ORIG:
7137 iter.cpu_file = raw_smp_processor_id();
7138 break;
7139 case DUMP_NONE:
7140 goto out_enable;
7141 default:
7142 printk(KERN_TRACE "Bad dumping mode, switching to all CPUs dump\n");
7143 iter.cpu_file = RING_BUFFER_ALL_CPUS;
7144 }
7145
7146 printk(KERN_TRACE "Dumping ftrace buffer:\n");
7147
7148 /* Did function tracer already get disabled? */
7149 if (ftrace_is_dead()) {
7150 printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
7151 printk("# MAY BE MISSING FUNCTION EVENTS\n");
7152 }
7153
7154 /*
7155 * We need to stop all tracing on all CPUS to read the
7156 * the next buffer. This is a bit expensive, but is
7157 * not done often. We fill all what we can read,
7158 * and then release the locks again.
7159 */
7160
7161 while (!trace_empty(&iter)) {
7162
7163 if (!cnt)
7164 printk(KERN_TRACE "---------------------------------\n");
7165
7166 cnt++;
7167
7168 /* reset all but tr, trace, and overruns */
7169 memset(&iter.seq, 0,
7170 sizeof(struct trace_iterator) -
7171 offsetof(struct trace_iterator, seq));
7172 iter.iter_flags |= TRACE_FILE_LAT_FMT;
7173 iter.pos = -1;
7174
7175 if (trace_find_next_entry_inc(&iter) != NULL) {
7176 int ret;
7177
7178 ret = print_trace_line(&iter);
7179 if (ret != TRACE_TYPE_NO_CONSUME)
7180 trace_consume(&iter);
7181 }
7182 touch_nmi_watchdog();
7183
7184 trace_printk_seq(&iter.seq);
7185 }
7186
7187 if (!cnt)
7188 printk(KERN_TRACE " (ftrace buffer empty)\n");
7189 else
7190 printk(KERN_TRACE "---------------------------------\n");
7191
7192 out_enable:
7193 tr->trace_flags |= old_userobj;
7194
7195 for_each_tracing_cpu(cpu) {
7196 atomic_dec(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
7197 }
7198 atomic_dec(&dump_running);
7199 local_irq_restore(flags);
7200}
7201EXPORT_SYMBOL_GPL(ftrace_dump);
7202
7203__init static int tracer_alloc_buffers(void)
7204{
7205 int ring_buf_size;
7206 int ret = -ENOMEM;
7207
7208 /*
7209 * Make sure we don't accidently add more trace options
7210 * than we have bits for.
7211 */
7212 BUILD_BUG_ON(TRACE_ITER_LAST_BIT > TRACE_FLAGS_MAX_SIZE);
7213
7214 if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
7215 goto out;
7216
7217 if (!alloc_cpumask_var(&global_trace.tracing_cpumask, GFP_KERNEL))
7218 goto out_free_buffer_mask;
7219
7220 /* Only allocate trace_printk buffers if a trace_printk exists */
7221 if (__stop___trace_bprintk_fmt != __start___trace_bprintk_fmt)
7222 /* Must be called before global_trace.buffer is allocated */
7223 trace_printk_init_buffers();
7224
7225 /* To save memory, keep the ring buffer size to its minimum */
7226 if (ring_buffer_expanded)
7227 ring_buf_size = trace_buf_size;
7228 else
7229 ring_buf_size = 1;
7230
7231 cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
7232 cpumask_copy(global_trace.tracing_cpumask, cpu_all_mask);
7233
7234 raw_spin_lock_init(&global_trace.start_lock);
7235
7236 /* Used for event triggers */
7237 temp_buffer = ring_buffer_alloc(PAGE_SIZE, RB_FL_OVERWRITE);
7238 if (!temp_buffer)
7239 goto out_free_cpumask;
7240
7241 if (trace_create_savedcmd() < 0)
7242 goto out_free_temp_buffer;
7243
7244 /* TODO: make the number of buffers hot pluggable with CPUS */
7245 if (allocate_trace_buffers(&global_trace, ring_buf_size) < 0) {
7246 printk(KERN_ERR "tracer: failed to allocate ring buffer!\n");
7247 WARN_ON(1);
7248 goto out_free_savedcmd;
7249 }
7250
7251 if (global_trace.buffer_disabled)
7252 tracing_off();
7253
7254 if (trace_boot_clock) {
7255 ret = tracing_set_clock(&global_trace, trace_boot_clock);
7256 if (ret < 0)
7257 pr_warn("Trace clock %s not defined, going back to default\n",
7258 trace_boot_clock);
7259 }
7260
7261 /*
7262 * register_tracer() might reference current_trace, so it
7263 * needs to be set before we register anything. This is
7264 * just a bootstrap of current_trace anyway.
7265 */
7266 global_trace.current_trace = &nop_trace;
7267
7268 global_trace.max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
7269
7270 ftrace_init_global_array_ops(&global_trace);
7271
7272 init_trace_flags_index(&global_trace);
7273
7274 register_tracer(&nop_trace);
7275
7276 /* All seems OK, enable tracing */
7277 tracing_disabled = 0;
7278
7279 atomic_notifier_chain_register(&panic_notifier_list,
7280 &trace_panic_notifier);
7281
7282 register_die_notifier(&trace_die_notifier);
7283
7284 global_trace.flags = TRACE_ARRAY_FL_GLOBAL;
7285
7286 INIT_LIST_HEAD(&global_trace.systems);
7287 INIT_LIST_HEAD(&global_trace.events);
7288 list_add(&global_trace.list, &ftrace_trace_arrays);
7289
7290 apply_trace_boot_options();
7291
7292 register_snapshot_cmd();
7293
7294 return 0;
7295
7296out_free_savedcmd:
7297 free_saved_cmdlines_buffer(savedcmd);
7298out_free_temp_buffer:
7299 ring_buffer_free(temp_buffer);
7300out_free_cpumask:
7301 free_cpumask_var(global_trace.tracing_cpumask);
7302out_free_buffer_mask:
7303 free_cpumask_var(tracing_buffer_mask);
7304out:
7305 return ret;
7306}
7307
7308void __init trace_init(void)
7309{
7310 if (tracepoint_printk) {
7311 tracepoint_print_iter =
7312 kmalloc(sizeof(*tracepoint_print_iter), GFP_KERNEL);
7313 if (WARN_ON(!tracepoint_print_iter))
7314 tracepoint_printk = 0;
7315 }
7316 tracer_alloc_buffers();
7317 trace_event_init();
7318}
7319
7320__init static int clear_boot_tracer(void)
7321{
7322 /*
7323 * The default tracer at boot buffer is an init section.
7324 * This function is called in lateinit. If we did not
7325 * find the boot tracer, then clear it out, to prevent
7326 * later registration from accessing the buffer that is
7327 * about to be freed.
7328 */
7329 if (!default_bootup_tracer)
7330 return 0;
7331
7332 printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n",
7333 default_bootup_tracer);
7334 default_bootup_tracer = NULL;
7335
7336 return 0;
7337}
7338
7339fs_initcall(tracer_init_tracefs);
7340late_initcall(clear_boot_tracer);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * ring buffer based function tracer
4 *
5 * Copyright (C) 2007-2012 Steven Rostedt <srostedt@redhat.com>
6 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
7 *
8 * Originally taken from the RT patch by:
9 * Arnaldo Carvalho de Melo <acme@redhat.com>
10 *
11 * Based on code from the latency_tracer, that is:
12 * Copyright (C) 2004-2006 Ingo Molnar
13 * Copyright (C) 2004 Nadia Yvette Chambers
14 */
15#include <linux/ring_buffer.h>
16#include <generated/utsrelease.h>
17#include <linux/stacktrace.h>
18#include <linux/writeback.h>
19#include <linux/kallsyms.h>
20#include <linux/security.h>
21#include <linux/seq_file.h>
22#include <linux/notifier.h>
23#include <linux/irqflags.h>
24#include <linux/debugfs.h>
25#include <linux/tracefs.h>
26#include <linux/pagemap.h>
27#include <linux/hardirq.h>
28#include <linux/linkage.h>
29#include <linux/uaccess.h>
30#include <linux/vmalloc.h>
31#include <linux/ftrace.h>
32#include <linux/module.h>
33#include <linux/percpu.h>
34#include <linux/splice.h>
35#include <linux/kdebug.h>
36#include <linux/string.h>
37#include <linux/mount.h>
38#include <linux/rwsem.h>
39#include <linux/slab.h>
40#include <linux/ctype.h>
41#include <linux/init.h>
42#include <linux/panic_notifier.h>
43#include <linux/poll.h>
44#include <linux/nmi.h>
45#include <linux/fs.h>
46#include <linux/trace.h>
47#include <linux/sched/clock.h>
48#include <linux/sched/rt.h>
49#include <linux/fsnotify.h>
50#include <linux/irq_work.h>
51#include <linux/workqueue.h>
52
53#include "trace.h"
54#include "trace_output.h"
55
56/*
57 * On boot up, the ring buffer is set to the minimum size, so that
58 * we do not waste memory on systems that are not using tracing.
59 */
60bool ring_buffer_expanded;
61
62/*
63 * We need to change this state when a selftest is running.
64 * A selftest will lurk into the ring-buffer to count the
65 * entries inserted during the selftest although some concurrent
66 * insertions into the ring-buffer such as trace_printk could occurred
67 * at the same time, giving false positive or negative results.
68 */
69static bool __read_mostly tracing_selftest_running;
70
71/*
72 * If boot-time tracing including tracers/events via kernel cmdline
73 * is running, we do not want to run SELFTEST.
74 */
75bool __read_mostly tracing_selftest_disabled;
76
77#ifdef CONFIG_FTRACE_STARTUP_TEST
78void __init disable_tracing_selftest(const char *reason)
79{
80 if (!tracing_selftest_disabled) {
81 tracing_selftest_disabled = true;
82 pr_info("Ftrace startup test is disabled due to %s\n", reason);
83 }
84}
85#endif
86
87/* Pipe tracepoints to printk */
88struct trace_iterator *tracepoint_print_iter;
89int tracepoint_printk;
90static bool tracepoint_printk_stop_on_boot __initdata;
91static DEFINE_STATIC_KEY_FALSE(tracepoint_printk_key);
92
93/* For tracers that don't implement custom flags */
94static struct tracer_opt dummy_tracer_opt[] = {
95 { }
96};
97
98static int
99dummy_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
100{
101 return 0;
102}
103
104/*
105 * To prevent the comm cache from being overwritten when no
106 * tracing is active, only save the comm when a trace event
107 * occurred.
108 */
109static DEFINE_PER_CPU(bool, trace_taskinfo_save);
110
111/*
112 * Kill all tracing for good (never come back).
113 * It is initialized to 1 but will turn to zero if the initialization
114 * of the tracer is successful. But that is the only place that sets
115 * this back to zero.
116 */
117static int tracing_disabled = 1;
118
119cpumask_var_t __read_mostly tracing_buffer_mask;
120
121/*
122 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
123 *
124 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
125 * is set, then ftrace_dump is called. This will output the contents
126 * of the ftrace buffers to the console. This is very useful for
127 * capturing traces that lead to crashes and outputing it to a
128 * serial console.
129 *
130 * It is default off, but you can enable it with either specifying
131 * "ftrace_dump_on_oops" in the kernel command line, or setting
132 * /proc/sys/kernel/ftrace_dump_on_oops
133 * Set 1 if you want to dump buffers of all CPUs
134 * Set 2 if you want to dump the buffer of the CPU that triggered oops
135 */
136
137enum ftrace_dump_mode ftrace_dump_on_oops;
138
139/* When set, tracing will stop when a WARN*() is hit */
140int __disable_trace_on_warning;
141
142#ifdef CONFIG_TRACE_EVAL_MAP_FILE
143/* Map of enums to their values, for "eval_map" file */
144struct trace_eval_map_head {
145 struct module *mod;
146 unsigned long length;
147};
148
149union trace_eval_map_item;
150
151struct trace_eval_map_tail {
152 /*
153 * "end" is first and points to NULL as it must be different
154 * than "mod" or "eval_string"
155 */
156 union trace_eval_map_item *next;
157 const char *end; /* points to NULL */
158};
159
160static DEFINE_MUTEX(trace_eval_mutex);
161
162/*
163 * The trace_eval_maps are saved in an array with two extra elements,
164 * one at the beginning, and one at the end. The beginning item contains
165 * the count of the saved maps (head.length), and the module they
166 * belong to if not built in (head.mod). The ending item contains a
167 * pointer to the next array of saved eval_map items.
168 */
169union trace_eval_map_item {
170 struct trace_eval_map map;
171 struct trace_eval_map_head head;
172 struct trace_eval_map_tail tail;
173};
174
175static union trace_eval_map_item *trace_eval_maps;
176#endif /* CONFIG_TRACE_EVAL_MAP_FILE */
177
178int tracing_set_tracer(struct trace_array *tr, const char *buf);
179static void ftrace_trace_userstack(struct trace_array *tr,
180 struct trace_buffer *buffer,
181 unsigned int trace_ctx);
182
183#define MAX_TRACER_SIZE 100
184static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata;
185static char *default_bootup_tracer;
186
187static bool allocate_snapshot;
188
189static int __init set_cmdline_ftrace(char *str)
190{
191 strlcpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
192 default_bootup_tracer = bootup_tracer_buf;
193 /* We are using ftrace early, expand it */
194 ring_buffer_expanded = true;
195 return 1;
196}
197__setup("ftrace=", set_cmdline_ftrace);
198
199static int __init set_ftrace_dump_on_oops(char *str)
200{
201 if (*str++ != '=' || !*str || !strcmp("1", str)) {
202 ftrace_dump_on_oops = DUMP_ALL;
203 return 1;
204 }
205
206 if (!strcmp("orig_cpu", str) || !strcmp("2", str)) {
207 ftrace_dump_on_oops = DUMP_ORIG;
208 return 1;
209 }
210
211 return 0;
212}
213__setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
214
215static int __init stop_trace_on_warning(char *str)
216{
217 if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
218 __disable_trace_on_warning = 1;
219 return 1;
220}
221__setup("traceoff_on_warning", stop_trace_on_warning);
222
223static int __init boot_alloc_snapshot(char *str)
224{
225 allocate_snapshot = true;
226 /* We also need the main ring buffer expanded */
227 ring_buffer_expanded = true;
228 return 1;
229}
230__setup("alloc_snapshot", boot_alloc_snapshot);
231
232
233static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata;
234
235static int __init set_trace_boot_options(char *str)
236{
237 strlcpy(trace_boot_options_buf, str, MAX_TRACER_SIZE);
238 return 0;
239}
240__setup("trace_options=", set_trace_boot_options);
241
242static char trace_boot_clock_buf[MAX_TRACER_SIZE] __initdata;
243static char *trace_boot_clock __initdata;
244
245static int __init set_trace_boot_clock(char *str)
246{
247 strlcpy(trace_boot_clock_buf, str, MAX_TRACER_SIZE);
248 trace_boot_clock = trace_boot_clock_buf;
249 return 0;
250}
251__setup("trace_clock=", set_trace_boot_clock);
252
253static int __init set_tracepoint_printk(char *str)
254{
255 if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
256 tracepoint_printk = 1;
257 return 1;
258}
259__setup("tp_printk", set_tracepoint_printk);
260
261static int __init set_tracepoint_printk_stop(char *str)
262{
263 tracepoint_printk_stop_on_boot = true;
264 return 1;
265}
266__setup("tp_printk_stop_on_boot", set_tracepoint_printk_stop);
267
268unsigned long long ns2usecs(u64 nsec)
269{
270 nsec += 500;
271 do_div(nsec, 1000);
272 return nsec;
273}
274
275static void
276trace_process_export(struct trace_export *export,
277 struct ring_buffer_event *event, int flag)
278{
279 struct trace_entry *entry;
280 unsigned int size = 0;
281
282 if (export->flags & flag) {
283 entry = ring_buffer_event_data(event);
284 size = ring_buffer_event_length(event);
285 export->write(export, entry, size);
286 }
287}
288
289static DEFINE_MUTEX(ftrace_export_lock);
290
291static struct trace_export __rcu *ftrace_exports_list __read_mostly;
292
293static DEFINE_STATIC_KEY_FALSE(trace_function_exports_enabled);
294static DEFINE_STATIC_KEY_FALSE(trace_event_exports_enabled);
295static DEFINE_STATIC_KEY_FALSE(trace_marker_exports_enabled);
296
297static inline void ftrace_exports_enable(struct trace_export *export)
298{
299 if (export->flags & TRACE_EXPORT_FUNCTION)
300 static_branch_inc(&trace_function_exports_enabled);
301
302 if (export->flags & TRACE_EXPORT_EVENT)
303 static_branch_inc(&trace_event_exports_enabled);
304
305 if (export->flags & TRACE_EXPORT_MARKER)
306 static_branch_inc(&trace_marker_exports_enabled);
307}
308
309static inline void ftrace_exports_disable(struct trace_export *export)
310{
311 if (export->flags & TRACE_EXPORT_FUNCTION)
312 static_branch_dec(&trace_function_exports_enabled);
313
314 if (export->flags & TRACE_EXPORT_EVENT)
315 static_branch_dec(&trace_event_exports_enabled);
316
317 if (export->flags & TRACE_EXPORT_MARKER)
318 static_branch_dec(&trace_marker_exports_enabled);
319}
320
321static void ftrace_exports(struct ring_buffer_event *event, int flag)
322{
323 struct trace_export *export;
324
325 preempt_disable_notrace();
326
327 export = rcu_dereference_raw_check(ftrace_exports_list);
328 while (export) {
329 trace_process_export(export, event, flag);
330 export = rcu_dereference_raw_check(export->next);
331 }
332
333 preempt_enable_notrace();
334}
335
336static inline void
337add_trace_export(struct trace_export **list, struct trace_export *export)
338{
339 rcu_assign_pointer(export->next, *list);
340 /*
341 * We are entering export into the list but another
342 * CPU might be walking that list. We need to make sure
343 * the export->next pointer is valid before another CPU sees
344 * the export pointer included into the list.
345 */
346 rcu_assign_pointer(*list, export);
347}
348
349static inline int
350rm_trace_export(struct trace_export **list, struct trace_export *export)
351{
352 struct trace_export **p;
353
354 for (p = list; *p != NULL; p = &(*p)->next)
355 if (*p == export)
356 break;
357
358 if (*p != export)
359 return -1;
360
361 rcu_assign_pointer(*p, (*p)->next);
362
363 return 0;
364}
365
366static inline void
367add_ftrace_export(struct trace_export **list, struct trace_export *export)
368{
369 ftrace_exports_enable(export);
370
371 add_trace_export(list, export);
372}
373
374static inline int
375rm_ftrace_export(struct trace_export **list, struct trace_export *export)
376{
377 int ret;
378
379 ret = rm_trace_export(list, export);
380 ftrace_exports_disable(export);
381
382 return ret;
383}
384
385int register_ftrace_export(struct trace_export *export)
386{
387 if (WARN_ON_ONCE(!export->write))
388 return -1;
389
390 mutex_lock(&ftrace_export_lock);
391
392 add_ftrace_export(&ftrace_exports_list, export);
393
394 mutex_unlock(&ftrace_export_lock);
395
396 return 0;
397}
398EXPORT_SYMBOL_GPL(register_ftrace_export);
399
400int unregister_ftrace_export(struct trace_export *export)
401{
402 int ret;
403
404 mutex_lock(&ftrace_export_lock);
405
406 ret = rm_ftrace_export(&ftrace_exports_list, export);
407
408 mutex_unlock(&ftrace_export_lock);
409
410 return ret;
411}
412EXPORT_SYMBOL_GPL(unregister_ftrace_export);
413
414/* trace_flags holds trace_options default values */
415#define TRACE_DEFAULT_FLAGS \
416 (FUNCTION_DEFAULT_FLAGS | \
417 TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK | \
418 TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | \
419 TRACE_ITER_RECORD_CMD | TRACE_ITER_OVERWRITE | \
420 TRACE_ITER_IRQ_INFO | TRACE_ITER_MARKERS | \
421 TRACE_ITER_HASH_PTR)
422
423/* trace_options that are only supported by global_trace */
424#define TOP_LEVEL_TRACE_FLAGS (TRACE_ITER_PRINTK | \
425 TRACE_ITER_PRINTK_MSGONLY | TRACE_ITER_RECORD_CMD)
426
427/* trace_flags that are default zero for instances */
428#define ZEROED_TRACE_FLAGS \
429 (TRACE_ITER_EVENT_FORK | TRACE_ITER_FUNC_FORK)
430
431/*
432 * The global_trace is the descriptor that holds the top-level tracing
433 * buffers for the live tracing.
434 */
435static struct trace_array global_trace = {
436 .trace_flags = TRACE_DEFAULT_FLAGS,
437};
438
439LIST_HEAD(ftrace_trace_arrays);
440
441int trace_array_get(struct trace_array *this_tr)
442{
443 struct trace_array *tr;
444 int ret = -ENODEV;
445
446 mutex_lock(&trace_types_lock);
447 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
448 if (tr == this_tr) {
449 tr->ref++;
450 ret = 0;
451 break;
452 }
453 }
454 mutex_unlock(&trace_types_lock);
455
456 return ret;
457}
458
459static void __trace_array_put(struct trace_array *this_tr)
460{
461 WARN_ON(!this_tr->ref);
462 this_tr->ref--;
463}
464
465/**
466 * trace_array_put - Decrement the reference counter for this trace array.
467 * @this_tr : pointer to the trace array
468 *
469 * NOTE: Use this when we no longer need the trace array returned by
470 * trace_array_get_by_name(). This ensures the trace array can be later
471 * destroyed.
472 *
473 */
474void trace_array_put(struct trace_array *this_tr)
475{
476 if (!this_tr)
477 return;
478
479 mutex_lock(&trace_types_lock);
480 __trace_array_put(this_tr);
481 mutex_unlock(&trace_types_lock);
482}
483EXPORT_SYMBOL_GPL(trace_array_put);
484
485int tracing_check_open_get_tr(struct trace_array *tr)
486{
487 int ret;
488
489 ret = security_locked_down(LOCKDOWN_TRACEFS);
490 if (ret)
491 return ret;
492
493 if (tracing_disabled)
494 return -ENODEV;
495
496 if (tr && trace_array_get(tr) < 0)
497 return -ENODEV;
498
499 return 0;
500}
501
502int call_filter_check_discard(struct trace_event_call *call, void *rec,
503 struct trace_buffer *buffer,
504 struct ring_buffer_event *event)
505{
506 if (unlikely(call->flags & TRACE_EVENT_FL_FILTERED) &&
507 !filter_match_preds(call->filter, rec)) {
508 __trace_event_discard_commit(buffer, event);
509 return 1;
510 }
511
512 return 0;
513}
514
515void trace_free_pid_list(struct trace_pid_list *pid_list)
516{
517 vfree(pid_list->pids);
518 kfree(pid_list);
519}
520
521/**
522 * trace_find_filtered_pid - check if a pid exists in a filtered_pid list
523 * @filtered_pids: The list of pids to check
524 * @search_pid: The PID to find in @filtered_pids
525 *
526 * Returns true if @search_pid is found in @filtered_pids, and false otherwise.
527 */
528bool
529trace_find_filtered_pid(struct trace_pid_list *filtered_pids, pid_t search_pid)
530{
531 /*
532 * If pid_max changed after filtered_pids was created, we
533 * by default ignore all pids greater than the previous pid_max.
534 */
535 if (search_pid >= filtered_pids->pid_max)
536 return false;
537
538 return test_bit(search_pid, filtered_pids->pids);
539}
540
541/**
542 * trace_ignore_this_task - should a task be ignored for tracing
543 * @filtered_pids: The list of pids to check
544 * @filtered_no_pids: The list of pids not to be traced
545 * @task: The task that should be ignored if not filtered
546 *
547 * Checks if @task should be traced or not from @filtered_pids.
548 * Returns true if @task should *NOT* be traced.
549 * Returns false if @task should be traced.
550 */
551bool
552trace_ignore_this_task(struct trace_pid_list *filtered_pids,
553 struct trace_pid_list *filtered_no_pids,
554 struct task_struct *task)
555{
556 /*
557 * If filtered_no_pids is not empty, and the task's pid is listed
558 * in filtered_no_pids, then return true.
559 * Otherwise, if filtered_pids is empty, that means we can
560 * trace all tasks. If it has content, then only trace pids
561 * within filtered_pids.
562 */
563
564 return (filtered_pids &&
565 !trace_find_filtered_pid(filtered_pids, task->pid)) ||
566 (filtered_no_pids &&
567 trace_find_filtered_pid(filtered_no_pids, task->pid));
568}
569
570/**
571 * trace_filter_add_remove_task - Add or remove a task from a pid_list
572 * @pid_list: The list to modify
573 * @self: The current task for fork or NULL for exit
574 * @task: The task to add or remove
575 *
576 * If adding a task, if @self is defined, the task is only added if @self
577 * is also included in @pid_list. This happens on fork and tasks should
578 * only be added when the parent is listed. If @self is NULL, then the
579 * @task pid will be removed from the list, which would happen on exit
580 * of a task.
581 */
582void trace_filter_add_remove_task(struct trace_pid_list *pid_list,
583 struct task_struct *self,
584 struct task_struct *task)
585{
586 if (!pid_list)
587 return;
588
589 /* For forks, we only add if the forking task is listed */
590 if (self) {
591 if (!trace_find_filtered_pid(pid_list, self->pid))
592 return;
593 }
594
595 /* Sorry, but we don't support pid_max changing after setting */
596 if (task->pid >= pid_list->pid_max)
597 return;
598
599 /* "self" is set for forks, and NULL for exits */
600 if (self)
601 set_bit(task->pid, pid_list->pids);
602 else
603 clear_bit(task->pid, pid_list->pids);
604}
605
606/**
607 * trace_pid_next - Used for seq_file to get to the next pid of a pid_list
608 * @pid_list: The pid list to show
609 * @v: The last pid that was shown (+1 the actual pid to let zero be displayed)
610 * @pos: The position of the file
611 *
612 * This is used by the seq_file "next" operation to iterate the pids
613 * listed in a trace_pid_list structure.
614 *
615 * Returns the pid+1 as we want to display pid of zero, but NULL would
616 * stop the iteration.
617 */
618void *trace_pid_next(struct trace_pid_list *pid_list, void *v, loff_t *pos)
619{
620 unsigned long pid = (unsigned long)v;
621
622 (*pos)++;
623
624 /* pid already is +1 of the actual previous bit */
625 pid = find_next_bit(pid_list->pids, pid_list->pid_max, pid);
626
627 /* Return pid + 1 to allow zero to be represented */
628 if (pid < pid_list->pid_max)
629 return (void *)(pid + 1);
630
631 return NULL;
632}
633
634/**
635 * trace_pid_start - Used for seq_file to start reading pid lists
636 * @pid_list: The pid list to show
637 * @pos: The position of the file
638 *
639 * This is used by seq_file "start" operation to start the iteration
640 * of listing pids.
641 *
642 * Returns the pid+1 as we want to display pid of zero, but NULL would
643 * stop the iteration.
644 */
645void *trace_pid_start(struct trace_pid_list *pid_list, loff_t *pos)
646{
647 unsigned long pid;
648 loff_t l = 0;
649
650 pid = find_first_bit(pid_list->pids, pid_list->pid_max);
651 if (pid >= pid_list->pid_max)
652 return NULL;
653
654 /* Return pid + 1 so that zero can be the exit value */
655 for (pid++; pid && l < *pos;
656 pid = (unsigned long)trace_pid_next(pid_list, (void *)pid, &l))
657 ;
658 return (void *)pid;
659}
660
661/**
662 * trace_pid_show - show the current pid in seq_file processing
663 * @m: The seq_file structure to write into
664 * @v: A void pointer of the pid (+1) value to display
665 *
666 * Can be directly used by seq_file operations to display the current
667 * pid value.
668 */
669int trace_pid_show(struct seq_file *m, void *v)
670{
671 unsigned long pid = (unsigned long)v - 1;
672
673 seq_printf(m, "%lu\n", pid);
674 return 0;
675}
676
677/* 128 should be much more than enough */
678#define PID_BUF_SIZE 127
679
680int trace_pid_write(struct trace_pid_list *filtered_pids,
681 struct trace_pid_list **new_pid_list,
682 const char __user *ubuf, size_t cnt)
683{
684 struct trace_pid_list *pid_list;
685 struct trace_parser parser;
686 unsigned long val;
687 int nr_pids = 0;
688 ssize_t read = 0;
689 ssize_t ret = 0;
690 loff_t pos;
691 pid_t pid;
692
693 if (trace_parser_get_init(&parser, PID_BUF_SIZE + 1))
694 return -ENOMEM;
695
696 /*
697 * Always recreate a new array. The write is an all or nothing
698 * operation. Always create a new array when adding new pids by
699 * the user. If the operation fails, then the current list is
700 * not modified.
701 */
702 pid_list = kmalloc(sizeof(*pid_list), GFP_KERNEL);
703 if (!pid_list) {
704 trace_parser_put(&parser);
705 return -ENOMEM;
706 }
707
708 pid_list->pid_max = READ_ONCE(pid_max);
709
710 /* Only truncating will shrink pid_max */
711 if (filtered_pids && filtered_pids->pid_max > pid_list->pid_max)
712 pid_list->pid_max = filtered_pids->pid_max;
713
714 pid_list->pids = vzalloc((pid_list->pid_max + 7) >> 3);
715 if (!pid_list->pids) {
716 trace_parser_put(&parser);
717 kfree(pid_list);
718 return -ENOMEM;
719 }
720
721 if (filtered_pids) {
722 /* copy the current bits to the new max */
723 for_each_set_bit(pid, filtered_pids->pids,
724 filtered_pids->pid_max) {
725 set_bit(pid, pid_list->pids);
726 nr_pids++;
727 }
728 }
729
730 while (cnt > 0) {
731
732 pos = 0;
733
734 ret = trace_get_user(&parser, ubuf, cnt, &pos);
735 if (ret < 0 || !trace_parser_loaded(&parser))
736 break;
737
738 read += ret;
739 ubuf += ret;
740 cnt -= ret;
741
742 ret = -EINVAL;
743 if (kstrtoul(parser.buffer, 0, &val))
744 break;
745 if (val >= pid_list->pid_max)
746 break;
747
748 pid = (pid_t)val;
749
750 set_bit(pid, pid_list->pids);
751 nr_pids++;
752
753 trace_parser_clear(&parser);
754 ret = 0;
755 }
756 trace_parser_put(&parser);
757
758 if (ret < 0) {
759 trace_free_pid_list(pid_list);
760 return ret;
761 }
762
763 if (!nr_pids) {
764 /* Cleared the list of pids */
765 trace_free_pid_list(pid_list);
766 read = ret;
767 pid_list = NULL;
768 }
769
770 *new_pid_list = pid_list;
771
772 return read;
773}
774
775static u64 buffer_ftrace_now(struct array_buffer *buf, int cpu)
776{
777 u64 ts;
778
779 /* Early boot up does not have a buffer yet */
780 if (!buf->buffer)
781 return trace_clock_local();
782
783 ts = ring_buffer_time_stamp(buf->buffer);
784 ring_buffer_normalize_time_stamp(buf->buffer, cpu, &ts);
785
786 return ts;
787}
788
789u64 ftrace_now(int cpu)
790{
791 return buffer_ftrace_now(&global_trace.array_buffer, cpu);
792}
793
794/**
795 * tracing_is_enabled - Show if global_trace has been enabled
796 *
797 * Shows if the global trace has been enabled or not. It uses the
798 * mirror flag "buffer_disabled" to be used in fast paths such as for
799 * the irqsoff tracer. But it may be inaccurate due to races. If you
800 * need to know the accurate state, use tracing_is_on() which is a little
801 * slower, but accurate.
802 */
803int tracing_is_enabled(void)
804{
805 /*
806 * For quick access (irqsoff uses this in fast path), just
807 * return the mirror variable of the state of the ring buffer.
808 * It's a little racy, but we don't really care.
809 */
810 smp_rmb();
811 return !global_trace.buffer_disabled;
812}
813
814/*
815 * trace_buf_size is the size in bytes that is allocated
816 * for a buffer. Note, the number of bytes is always rounded
817 * to page size.
818 *
819 * This number is purposely set to a low number of 16384.
820 * If the dump on oops happens, it will be much appreciated
821 * to not have to wait for all that output. Anyway this can be
822 * boot time and run time configurable.
823 */
824#define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
825
826static unsigned long trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
827
828/* trace_types holds a link list of available tracers. */
829static struct tracer *trace_types __read_mostly;
830
831/*
832 * trace_types_lock is used to protect the trace_types list.
833 */
834DEFINE_MUTEX(trace_types_lock);
835
836/*
837 * serialize the access of the ring buffer
838 *
839 * ring buffer serializes readers, but it is low level protection.
840 * The validity of the events (which returns by ring_buffer_peek() ..etc)
841 * are not protected by ring buffer.
842 *
843 * The content of events may become garbage if we allow other process consumes
844 * these events concurrently:
845 * A) the page of the consumed events may become a normal page
846 * (not reader page) in ring buffer, and this page will be rewritten
847 * by events producer.
848 * B) The page of the consumed events may become a page for splice_read,
849 * and this page will be returned to system.
850 *
851 * These primitives allow multi process access to different cpu ring buffer
852 * concurrently.
853 *
854 * These primitives don't distinguish read-only and read-consume access.
855 * Multi read-only access are also serialized.
856 */
857
858#ifdef CONFIG_SMP
859static DECLARE_RWSEM(all_cpu_access_lock);
860static DEFINE_PER_CPU(struct mutex, cpu_access_lock);
861
862static inline void trace_access_lock(int cpu)
863{
864 if (cpu == RING_BUFFER_ALL_CPUS) {
865 /* gain it for accessing the whole ring buffer. */
866 down_write(&all_cpu_access_lock);
867 } else {
868 /* gain it for accessing a cpu ring buffer. */
869
870 /* Firstly block other trace_access_lock(RING_BUFFER_ALL_CPUS). */
871 down_read(&all_cpu_access_lock);
872
873 /* Secondly block other access to this @cpu ring buffer. */
874 mutex_lock(&per_cpu(cpu_access_lock, cpu));
875 }
876}
877
878static inline void trace_access_unlock(int cpu)
879{
880 if (cpu == RING_BUFFER_ALL_CPUS) {
881 up_write(&all_cpu_access_lock);
882 } else {
883 mutex_unlock(&per_cpu(cpu_access_lock, cpu));
884 up_read(&all_cpu_access_lock);
885 }
886}
887
888static inline void trace_access_lock_init(void)
889{
890 int cpu;
891
892 for_each_possible_cpu(cpu)
893 mutex_init(&per_cpu(cpu_access_lock, cpu));
894}
895
896#else
897
898static DEFINE_MUTEX(access_lock);
899
900static inline void trace_access_lock(int cpu)
901{
902 (void)cpu;
903 mutex_lock(&access_lock);
904}
905
906static inline void trace_access_unlock(int cpu)
907{
908 (void)cpu;
909 mutex_unlock(&access_lock);
910}
911
912static inline void trace_access_lock_init(void)
913{
914}
915
916#endif
917
918#ifdef CONFIG_STACKTRACE
919static void __ftrace_trace_stack(struct trace_buffer *buffer,
920 unsigned int trace_ctx,
921 int skip, struct pt_regs *regs);
922static inline void ftrace_trace_stack(struct trace_array *tr,
923 struct trace_buffer *buffer,
924 unsigned int trace_ctx,
925 int skip, struct pt_regs *regs);
926
927#else
928static inline void __ftrace_trace_stack(struct trace_buffer *buffer,
929 unsigned int trace_ctx,
930 int skip, struct pt_regs *regs)
931{
932}
933static inline void ftrace_trace_stack(struct trace_array *tr,
934 struct trace_buffer *buffer,
935 unsigned long trace_ctx,
936 int skip, struct pt_regs *regs)
937{
938}
939
940#endif
941
942static __always_inline void
943trace_event_setup(struct ring_buffer_event *event,
944 int type, unsigned int trace_ctx)
945{
946 struct trace_entry *ent = ring_buffer_event_data(event);
947
948 tracing_generic_entry_update(ent, type, trace_ctx);
949}
950
951static __always_inline struct ring_buffer_event *
952__trace_buffer_lock_reserve(struct trace_buffer *buffer,
953 int type,
954 unsigned long len,
955 unsigned int trace_ctx)
956{
957 struct ring_buffer_event *event;
958
959 event = ring_buffer_lock_reserve(buffer, len);
960 if (event != NULL)
961 trace_event_setup(event, type, trace_ctx);
962
963 return event;
964}
965
966void tracer_tracing_on(struct trace_array *tr)
967{
968 if (tr->array_buffer.buffer)
969 ring_buffer_record_on(tr->array_buffer.buffer);
970 /*
971 * This flag is looked at when buffers haven't been allocated
972 * yet, or by some tracers (like irqsoff), that just want to
973 * know if the ring buffer has been disabled, but it can handle
974 * races of where it gets disabled but we still do a record.
975 * As the check is in the fast path of the tracers, it is more
976 * important to be fast than accurate.
977 */
978 tr->buffer_disabled = 0;
979 /* Make the flag seen by readers */
980 smp_wmb();
981}
982
983/**
984 * tracing_on - enable tracing buffers
985 *
986 * This function enables tracing buffers that may have been
987 * disabled with tracing_off.
988 */
989void tracing_on(void)
990{
991 tracer_tracing_on(&global_trace);
992}
993EXPORT_SYMBOL_GPL(tracing_on);
994
995
996static __always_inline void
997__buffer_unlock_commit(struct trace_buffer *buffer, struct ring_buffer_event *event)
998{
999 __this_cpu_write(trace_taskinfo_save, true);
1000
1001 /* If this is the temp buffer, we need to commit fully */
1002 if (this_cpu_read(trace_buffered_event) == event) {
1003 /* Length is in event->array[0] */
1004 ring_buffer_write(buffer, event->array[0], &event->array[1]);
1005 /* Release the temp buffer */
1006 this_cpu_dec(trace_buffered_event_cnt);
1007 } else
1008 ring_buffer_unlock_commit(buffer, event);
1009}
1010
1011/**
1012 * __trace_puts - write a constant string into the trace buffer.
1013 * @ip: The address of the caller
1014 * @str: The constant string to write
1015 * @size: The size of the string.
1016 */
1017int __trace_puts(unsigned long ip, const char *str, int size)
1018{
1019 struct ring_buffer_event *event;
1020 struct trace_buffer *buffer;
1021 struct print_entry *entry;
1022 unsigned int trace_ctx;
1023 int alloc;
1024
1025 if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
1026 return 0;
1027
1028 if (unlikely(tracing_selftest_running || tracing_disabled))
1029 return 0;
1030
1031 alloc = sizeof(*entry) + size + 2; /* possible \n added */
1032
1033 trace_ctx = tracing_gen_ctx();
1034 buffer = global_trace.array_buffer.buffer;
1035 ring_buffer_nest_start(buffer);
1036 event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc,
1037 trace_ctx);
1038 if (!event) {
1039 size = 0;
1040 goto out;
1041 }
1042
1043 entry = ring_buffer_event_data(event);
1044 entry->ip = ip;
1045
1046 memcpy(&entry->buf, str, size);
1047
1048 /* Add a newline if necessary */
1049 if (entry->buf[size - 1] != '\n') {
1050 entry->buf[size] = '\n';
1051 entry->buf[size + 1] = '\0';
1052 } else
1053 entry->buf[size] = '\0';
1054
1055 __buffer_unlock_commit(buffer, event);
1056 ftrace_trace_stack(&global_trace, buffer, trace_ctx, 4, NULL);
1057 out:
1058 ring_buffer_nest_end(buffer);
1059 return size;
1060}
1061EXPORT_SYMBOL_GPL(__trace_puts);
1062
1063/**
1064 * __trace_bputs - write the pointer to a constant string into trace buffer
1065 * @ip: The address of the caller
1066 * @str: The constant string to write to the buffer to
1067 */
1068int __trace_bputs(unsigned long ip, const char *str)
1069{
1070 struct ring_buffer_event *event;
1071 struct trace_buffer *buffer;
1072 struct bputs_entry *entry;
1073 unsigned int trace_ctx;
1074 int size = sizeof(struct bputs_entry);
1075 int ret = 0;
1076
1077 if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
1078 return 0;
1079
1080 if (unlikely(tracing_selftest_running || tracing_disabled))
1081 return 0;
1082
1083 trace_ctx = tracing_gen_ctx();
1084 buffer = global_trace.array_buffer.buffer;
1085
1086 ring_buffer_nest_start(buffer);
1087 event = __trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size,
1088 trace_ctx);
1089 if (!event)
1090 goto out;
1091
1092 entry = ring_buffer_event_data(event);
1093 entry->ip = ip;
1094 entry->str = str;
1095
1096 __buffer_unlock_commit(buffer, event);
1097 ftrace_trace_stack(&global_trace, buffer, trace_ctx, 4, NULL);
1098
1099 ret = 1;
1100 out:
1101 ring_buffer_nest_end(buffer);
1102 return ret;
1103}
1104EXPORT_SYMBOL_GPL(__trace_bputs);
1105
1106#ifdef CONFIG_TRACER_SNAPSHOT
1107static void tracing_snapshot_instance_cond(struct trace_array *tr,
1108 void *cond_data)
1109{
1110 struct tracer *tracer = tr->current_trace;
1111 unsigned long flags;
1112
1113 if (in_nmi()) {
1114 internal_trace_puts("*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n");
1115 internal_trace_puts("*** snapshot is being ignored ***\n");
1116 return;
1117 }
1118
1119 if (!tr->allocated_snapshot) {
1120 internal_trace_puts("*** SNAPSHOT NOT ALLOCATED ***\n");
1121 internal_trace_puts("*** stopping trace here! ***\n");
1122 tracing_off();
1123 return;
1124 }
1125
1126 /* Note, snapshot can not be used when the tracer uses it */
1127 if (tracer->use_max_tr) {
1128 internal_trace_puts("*** LATENCY TRACER ACTIVE ***\n");
1129 internal_trace_puts("*** Can not use snapshot (sorry) ***\n");
1130 return;
1131 }
1132
1133 local_irq_save(flags);
1134 update_max_tr(tr, current, smp_processor_id(), cond_data);
1135 local_irq_restore(flags);
1136}
1137
1138void tracing_snapshot_instance(struct trace_array *tr)
1139{
1140 tracing_snapshot_instance_cond(tr, NULL);
1141}
1142
1143/**
1144 * tracing_snapshot - take a snapshot of the current buffer.
1145 *
1146 * This causes a swap between the snapshot buffer and the current live
1147 * tracing buffer. You can use this to take snapshots of the live
1148 * trace when some condition is triggered, but continue to trace.
1149 *
1150 * Note, make sure to allocate the snapshot with either
1151 * a tracing_snapshot_alloc(), or by doing it manually
1152 * with: echo 1 > /sys/kernel/debug/tracing/snapshot
1153 *
1154 * If the snapshot buffer is not allocated, it will stop tracing.
1155 * Basically making a permanent snapshot.
1156 */
1157void tracing_snapshot(void)
1158{
1159 struct trace_array *tr = &global_trace;
1160
1161 tracing_snapshot_instance(tr);
1162}
1163EXPORT_SYMBOL_GPL(tracing_snapshot);
1164
1165/**
1166 * tracing_snapshot_cond - conditionally take a snapshot of the current buffer.
1167 * @tr: The tracing instance to snapshot
1168 * @cond_data: The data to be tested conditionally, and possibly saved
1169 *
1170 * This is the same as tracing_snapshot() except that the snapshot is
1171 * conditional - the snapshot will only happen if the
1172 * cond_snapshot.update() implementation receiving the cond_data
1173 * returns true, which means that the trace array's cond_snapshot
1174 * update() operation used the cond_data to determine whether the
1175 * snapshot should be taken, and if it was, presumably saved it along
1176 * with the snapshot.
1177 */
1178void tracing_snapshot_cond(struct trace_array *tr, void *cond_data)
1179{
1180 tracing_snapshot_instance_cond(tr, cond_data);
1181}
1182EXPORT_SYMBOL_GPL(tracing_snapshot_cond);
1183
1184/**
1185 * tracing_snapshot_cond_data - get the user data associated with a snapshot
1186 * @tr: The tracing instance
1187 *
1188 * When the user enables a conditional snapshot using
1189 * tracing_snapshot_cond_enable(), the user-defined cond_data is saved
1190 * with the snapshot. This accessor is used to retrieve it.
1191 *
1192 * Should not be called from cond_snapshot.update(), since it takes
1193 * the tr->max_lock lock, which the code calling
1194 * cond_snapshot.update() has already done.
1195 *
1196 * Returns the cond_data associated with the trace array's snapshot.
1197 */
1198void *tracing_cond_snapshot_data(struct trace_array *tr)
1199{
1200 void *cond_data = NULL;
1201
1202 arch_spin_lock(&tr->max_lock);
1203
1204 if (tr->cond_snapshot)
1205 cond_data = tr->cond_snapshot->cond_data;
1206
1207 arch_spin_unlock(&tr->max_lock);
1208
1209 return cond_data;
1210}
1211EXPORT_SYMBOL_GPL(tracing_cond_snapshot_data);
1212
1213static int resize_buffer_duplicate_size(struct array_buffer *trace_buf,
1214 struct array_buffer *size_buf, int cpu_id);
1215static void set_buffer_entries(struct array_buffer *buf, unsigned long val);
1216
1217int tracing_alloc_snapshot_instance(struct trace_array *tr)
1218{
1219 int ret;
1220
1221 if (!tr->allocated_snapshot) {
1222
1223 /* allocate spare buffer */
1224 ret = resize_buffer_duplicate_size(&tr->max_buffer,
1225 &tr->array_buffer, RING_BUFFER_ALL_CPUS);
1226 if (ret < 0)
1227 return ret;
1228
1229 tr->allocated_snapshot = true;
1230 }
1231
1232 return 0;
1233}
1234
1235static void free_snapshot(struct trace_array *tr)
1236{
1237 /*
1238 * We don't free the ring buffer. instead, resize it because
1239 * The max_tr ring buffer has some state (e.g. ring->clock) and
1240 * we want preserve it.
1241 */
1242 ring_buffer_resize(tr->max_buffer.buffer, 1, RING_BUFFER_ALL_CPUS);
1243 set_buffer_entries(&tr->max_buffer, 1);
1244 tracing_reset_online_cpus(&tr->max_buffer);
1245 tr->allocated_snapshot = false;
1246}
1247
1248/**
1249 * tracing_alloc_snapshot - allocate snapshot buffer.
1250 *
1251 * This only allocates the snapshot buffer if it isn't already
1252 * allocated - it doesn't also take a snapshot.
1253 *
1254 * This is meant to be used in cases where the snapshot buffer needs
1255 * to be set up for events that can't sleep but need to be able to
1256 * trigger a snapshot.
1257 */
1258int tracing_alloc_snapshot(void)
1259{
1260 struct trace_array *tr = &global_trace;
1261 int ret;
1262
1263 ret = tracing_alloc_snapshot_instance(tr);
1264 WARN_ON(ret < 0);
1265
1266 return ret;
1267}
1268EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
1269
1270/**
1271 * tracing_snapshot_alloc - allocate and take a snapshot of the current buffer.
1272 *
1273 * This is similar to tracing_snapshot(), but it will allocate the
1274 * snapshot buffer if it isn't already allocated. Use this only
1275 * where it is safe to sleep, as the allocation may sleep.
1276 *
1277 * This causes a swap between the snapshot buffer and the current live
1278 * tracing buffer. You can use this to take snapshots of the live
1279 * trace when some condition is triggered, but continue to trace.
1280 */
1281void tracing_snapshot_alloc(void)
1282{
1283 int ret;
1284
1285 ret = tracing_alloc_snapshot();
1286 if (ret < 0)
1287 return;
1288
1289 tracing_snapshot();
1290}
1291EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
1292
1293/**
1294 * tracing_snapshot_cond_enable - enable conditional snapshot for an instance
1295 * @tr: The tracing instance
1296 * @cond_data: User data to associate with the snapshot
1297 * @update: Implementation of the cond_snapshot update function
1298 *
1299 * Check whether the conditional snapshot for the given instance has
1300 * already been enabled, or if the current tracer is already using a
1301 * snapshot; if so, return -EBUSY, else create a cond_snapshot and
1302 * save the cond_data and update function inside.
1303 *
1304 * Returns 0 if successful, error otherwise.
1305 */
1306int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data,
1307 cond_update_fn_t update)
1308{
1309 struct cond_snapshot *cond_snapshot;
1310 int ret = 0;
1311
1312 cond_snapshot = kzalloc(sizeof(*cond_snapshot), GFP_KERNEL);
1313 if (!cond_snapshot)
1314 return -ENOMEM;
1315
1316 cond_snapshot->cond_data = cond_data;
1317 cond_snapshot->update = update;
1318
1319 mutex_lock(&trace_types_lock);
1320
1321 ret = tracing_alloc_snapshot_instance(tr);
1322 if (ret)
1323 goto fail_unlock;
1324
1325 if (tr->current_trace->use_max_tr) {
1326 ret = -EBUSY;
1327 goto fail_unlock;
1328 }
1329
1330 /*
1331 * The cond_snapshot can only change to NULL without the
1332 * trace_types_lock. We don't care if we race with it going
1333 * to NULL, but we want to make sure that it's not set to
1334 * something other than NULL when we get here, which we can
1335 * do safely with only holding the trace_types_lock and not
1336 * having to take the max_lock.
1337 */
1338 if (tr->cond_snapshot) {
1339 ret = -EBUSY;
1340 goto fail_unlock;
1341 }
1342
1343 arch_spin_lock(&tr->max_lock);
1344 tr->cond_snapshot = cond_snapshot;
1345 arch_spin_unlock(&tr->max_lock);
1346
1347 mutex_unlock(&trace_types_lock);
1348
1349 return ret;
1350
1351 fail_unlock:
1352 mutex_unlock(&trace_types_lock);
1353 kfree(cond_snapshot);
1354 return ret;
1355}
1356EXPORT_SYMBOL_GPL(tracing_snapshot_cond_enable);
1357
1358/**
1359 * tracing_snapshot_cond_disable - disable conditional snapshot for an instance
1360 * @tr: The tracing instance
1361 *
1362 * Check whether the conditional snapshot for the given instance is
1363 * enabled; if so, free the cond_snapshot associated with it,
1364 * otherwise return -EINVAL.
1365 *
1366 * Returns 0 if successful, error otherwise.
1367 */
1368int tracing_snapshot_cond_disable(struct trace_array *tr)
1369{
1370 int ret = 0;
1371
1372 arch_spin_lock(&tr->max_lock);
1373
1374 if (!tr->cond_snapshot)
1375 ret = -EINVAL;
1376 else {
1377 kfree(tr->cond_snapshot);
1378 tr->cond_snapshot = NULL;
1379 }
1380
1381 arch_spin_unlock(&tr->max_lock);
1382
1383 return ret;
1384}
1385EXPORT_SYMBOL_GPL(tracing_snapshot_cond_disable);
1386#else
1387void tracing_snapshot(void)
1388{
1389 WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used");
1390}
1391EXPORT_SYMBOL_GPL(tracing_snapshot);
1392void tracing_snapshot_cond(struct trace_array *tr, void *cond_data)
1393{
1394 WARN_ONCE(1, "Snapshot feature not enabled, but internal conditional snapshot used");
1395}
1396EXPORT_SYMBOL_GPL(tracing_snapshot_cond);
1397int tracing_alloc_snapshot(void)
1398{
1399 WARN_ONCE(1, "Snapshot feature not enabled, but snapshot allocation used");
1400 return -ENODEV;
1401}
1402EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
1403void tracing_snapshot_alloc(void)
1404{
1405 /* Give warning */
1406 tracing_snapshot();
1407}
1408EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
1409void *tracing_cond_snapshot_data(struct trace_array *tr)
1410{
1411 return NULL;
1412}
1413EXPORT_SYMBOL_GPL(tracing_cond_snapshot_data);
1414int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data, cond_update_fn_t update)
1415{
1416 return -ENODEV;
1417}
1418EXPORT_SYMBOL_GPL(tracing_snapshot_cond_enable);
1419int tracing_snapshot_cond_disable(struct trace_array *tr)
1420{
1421 return false;
1422}
1423EXPORT_SYMBOL_GPL(tracing_snapshot_cond_disable);
1424#endif /* CONFIG_TRACER_SNAPSHOT */
1425
1426void tracer_tracing_off(struct trace_array *tr)
1427{
1428 if (tr->array_buffer.buffer)
1429 ring_buffer_record_off(tr->array_buffer.buffer);
1430 /*
1431 * This flag is looked at when buffers haven't been allocated
1432 * yet, or by some tracers (like irqsoff), that just want to
1433 * know if the ring buffer has been disabled, but it can handle
1434 * races of where it gets disabled but we still do a record.
1435 * As the check is in the fast path of the tracers, it is more
1436 * important to be fast than accurate.
1437 */
1438 tr->buffer_disabled = 1;
1439 /* Make the flag seen by readers */
1440 smp_wmb();
1441}
1442
1443/**
1444 * tracing_off - turn off tracing buffers
1445 *
1446 * This function stops the tracing buffers from recording data.
1447 * It does not disable any overhead the tracers themselves may
1448 * be causing. This function simply causes all recording to
1449 * the ring buffers to fail.
1450 */
1451void tracing_off(void)
1452{
1453 tracer_tracing_off(&global_trace);
1454}
1455EXPORT_SYMBOL_GPL(tracing_off);
1456
1457void disable_trace_on_warning(void)
1458{
1459 if (__disable_trace_on_warning) {
1460 trace_array_printk_buf(global_trace.array_buffer.buffer, _THIS_IP_,
1461 "Disabling tracing due to warning\n");
1462 tracing_off();
1463 }
1464}
1465
1466/**
1467 * tracer_tracing_is_on - show real state of ring buffer enabled
1468 * @tr : the trace array to know if ring buffer is enabled
1469 *
1470 * Shows real state of the ring buffer if it is enabled or not.
1471 */
1472bool tracer_tracing_is_on(struct trace_array *tr)
1473{
1474 if (tr->array_buffer.buffer)
1475 return ring_buffer_record_is_on(tr->array_buffer.buffer);
1476 return !tr->buffer_disabled;
1477}
1478
1479/**
1480 * tracing_is_on - show state of ring buffers enabled
1481 */
1482int tracing_is_on(void)
1483{
1484 return tracer_tracing_is_on(&global_trace);
1485}
1486EXPORT_SYMBOL_GPL(tracing_is_on);
1487
1488static int __init set_buf_size(char *str)
1489{
1490 unsigned long buf_size;
1491
1492 if (!str)
1493 return 0;
1494 buf_size = memparse(str, &str);
1495 /* nr_entries can not be zero */
1496 if (buf_size == 0)
1497 return 0;
1498 trace_buf_size = buf_size;
1499 return 1;
1500}
1501__setup("trace_buf_size=", set_buf_size);
1502
1503static int __init set_tracing_thresh(char *str)
1504{
1505 unsigned long threshold;
1506 int ret;
1507
1508 if (!str)
1509 return 0;
1510 ret = kstrtoul(str, 0, &threshold);
1511 if (ret < 0)
1512 return 0;
1513 tracing_thresh = threshold * 1000;
1514 return 1;
1515}
1516__setup("tracing_thresh=", set_tracing_thresh);
1517
1518unsigned long nsecs_to_usecs(unsigned long nsecs)
1519{
1520 return nsecs / 1000;
1521}
1522
1523/*
1524 * TRACE_FLAGS is defined as a tuple matching bit masks with strings.
1525 * It uses C(a, b) where 'a' is the eval (enum) name and 'b' is the string that
1526 * matches it. By defining "C(a, b) b", TRACE_FLAGS becomes a list
1527 * of strings in the order that the evals (enum) were defined.
1528 */
1529#undef C
1530#define C(a, b) b
1531
1532/* These must match the bit positions in trace_iterator_flags */
1533static const char *trace_options[] = {
1534 TRACE_FLAGS
1535 NULL
1536};
1537
1538static struct {
1539 u64 (*func)(void);
1540 const char *name;
1541 int in_ns; /* is this clock in nanoseconds? */
1542} trace_clocks[] = {
1543 { trace_clock_local, "local", 1 },
1544 { trace_clock_global, "global", 1 },
1545 { trace_clock_counter, "counter", 0 },
1546 { trace_clock_jiffies, "uptime", 0 },
1547 { trace_clock, "perf", 1 },
1548 { ktime_get_mono_fast_ns, "mono", 1 },
1549 { ktime_get_raw_fast_ns, "mono_raw", 1 },
1550 { ktime_get_boot_fast_ns, "boot", 1 },
1551 ARCH_TRACE_CLOCKS
1552};
1553
1554bool trace_clock_in_ns(struct trace_array *tr)
1555{
1556 if (trace_clocks[tr->clock_id].in_ns)
1557 return true;
1558
1559 return false;
1560}
1561
1562/*
1563 * trace_parser_get_init - gets the buffer for trace parser
1564 */
1565int trace_parser_get_init(struct trace_parser *parser, int size)
1566{
1567 memset(parser, 0, sizeof(*parser));
1568
1569 parser->buffer = kmalloc(size, GFP_KERNEL);
1570 if (!parser->buffer)
1571 return 1;
1572
1573 parser->size = size;
1574 return 0;
1575}
1576
1577/*
1578 * trace_parser_put - frees the buffer for trace parser
1579 */
1580void trace_parser_put(struct trace_parser *parser)
1581{
1582 kfree(parser->buffer);
1583 parser->buffer = NULL;
1584}
1585
1586/*
1587 * trace_get_user - reads the user input string separated by space
1588 * (matched by isspace(ch))
1589 *
1590 * For each string found the 'struct trace_parser' is updated,
1591 * and the function returns.
1592 *
1593 * Returns number of bytes read.
1594 *
1595 * See kernel/trace/trace.h for 'struct trace_parser' details.
1596 */
1597int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
1598 size_t cnt, loff_t *ppos)
1599{
1600 char ch;
1601 size_t read = 0;
1602 ssize_t ret;
1603
1604 if (!*ppos)
1605 trace_parser_clear(parser);
1606
1607 ret = get_user(ch, ubuf++);
1608 if (ret)
1609 goto out;
1610
1611 read++;
1612 cnt--;
1613
1614 /*
1615 * The parser is not finished with the last write,
1616 * continue reading the user input without skipping spaces.
1617 */
1618 if (!parser->cont) {
1619 /* skip white space */
1620 while (cnt && isspace(ch)) {
1621 ret = get_user(ch, ubuf++);
1622 if (ret)
1623 goto out;
1624 read++;
1625 cnt--;
1626 }
1627
1628 parser->idx = 0;
1629
1630 /* only spaces were written */
1631 if (isspace(ch) || !ch) {
1632 *ppos += read;
1633 ret = read;
1634 goto out;
1635 }
1636 }
1637
1638 /* read the non-space input */
1639 while (cnt && !isspace(ch) && ch) {
1640 if (parser->idx < parser->size - 1)
1641 parser->buffer[parser->idx++] = ch;
1642 else {
1643 ret = -EINVAL;
1644 goto out;
1645 }
1646 ret = get_user(ch, ubuf++);
1647 if (ret)
1648 goto out;
1649 read++;
1650 cnt--;
1651 }
1652
1653 /* We either got finished input or we have to wait for another call. */
1654 if (isspace(ch) || !ch) {
1655 parser->buffer[parser->idx] = 0;
1656 parser->cont = false;
1657 } else if (parser->idx < parser->size - 1) {
1658 parser->cont = true;
1659 parser->buffer[parser->idx++] = ch;
1660 /* Make sure the parsed string always terminates with '\0'. */
1661 parser->buffer[parser->idx] = 0;
1662 } else {
1663 ret = -EINVAL;
1664 goto out;
1665 }
1666
1667 *ppos += read;
1668 ret = read;
1669
1670out:
1671 return ret;
1672}
1673
1674/* TODO add a seq_buf_to_buffer() */
1675static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
1676{
1677 int len;
1678
1679 if (trace_seq_used(s) <= s->seq.readpos)
1680 return -EBUSY;
1681
1682 len = trace_seq_used(s) - s->seq.readpos;
1683 if (cnt > len)
1684 cnt = len;
1685 memcpy(buf, s->buffer + s->seq.readpos, cnt);
1686
1687 s->seq.readpos += cnt;
1688 return cnt;
1689}
1690
1691unsigned long __read_mostly tracing_thresh;
1692static const struct file_operations tracing_max_lat_fops;
1693
1694#ifdef LATENCY_FS_NOTIFY
1695
1696static struct workqueue_struct *fsnotify_wq;
1697
1698static void latency_fsnotify_workfn(struct work_struct *work)
1699{
1700 struct trace_array *tr = container_of(work, struct trace_array,
1701 fsnotify_work);
1702 fsnotify_inode(tr->d_max_latency->d_inode, FS_MODIFY);
1703}
1704
1705static void latency_fsnotify_workfn_irq(struct irq_work *iwork)
1706{
1707 struct trace_array *tr = container_of(iwork, struct trace_array,
1708 fsnotify_irqwork);
1709 queue_work(fsnotify_wq, &tr->fsnotify_work);
1710}
1711
1712static void trace_create_maxlat_file(struct trace_array *tr,
1713 struct dentry *d_tracer)
1714{
1715 INIT_WORK(&tr->fsnotify_work, latency_fsnotify_workfn);
1716 init_irq_work(&tr->fsnotify_irqwork, latency_fsnotify_workfn_irq);
1717 tr->d_max_latency = trace_create_file("tracing_max_latency", 0644,
1718 d_tracer, &tr->max_latency,
1719 &tracing_max_lat_fops);
1720}
1721
1722__init static int latency_fsnotify_init(void)
1723{
1724 fsnotify_wq = alloc_workqueue("tr_max_lat_wq",
1725 WQ_UNBOUND | WQ_HIGHPRI, 0);
1726 if (!fsnotify_wq) {
1727 pr_err("Unable to allocate tr_max_lat_wq\n");
1728 return -ENOMEM;
1729 }
1730 return 0;
1731}
1732
1733late_initcall_sync(latency_fsnotify_init);
1734
1735void latency_fsnotify(struct trace_array *tr)
1736{
1737 if (!fsnotify_wq)
1738 return;
1739 /*
1740 * We cannot call queue_work(&tr->fsnotify_work) from here because it's
1741 * possible that we are called from __schedule() or do_idle(), which
1742 * could cause a deadlock.
1743 */
1744 irq_work_queue(&tr->fsnotify_irqwork);
1745}
1746
1747#elif defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER) \
1748 || defined(CONFIG_OSNOISE_TRACER)
1749
1750#define trace_create_maxlat_file(tr, d_tracer) \
1751 trace_create_file("tracing_max_latency", 0644, d_tracer, \
1752 &tr->max_latency, &tracing_max_lat_fops)
1753
1754#else
1755#define trace_create_maxlat_file(tr, d_tracer) do { } while (0)
1756#endif
1757
1758#ifdef CONFIG_TRACER_MAX_TRACE
1759/*
1760 * Copy the new maximum trace into the separate maximum-trace
1761 * structure. (this way the maximum trace is permanently saved,
1762 * for later retrieval via /sys/kernel/tracing/tracing_max_latency)
1763 */
1764static void
1765__update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
1766{
1767 struct array_buffer *trace_buf = &tr->array_buffer;
1768 struct array_buffer *max_buf = &tr->max_buffer;
1769 struct trace_array_cpu *data = per_cpu_ptr(trace_buf->data, cpu);
1770 struct trace_array_cpu *max_data = per_cpu_ptr(max_buf->data, cpu);
1771
1772 max_buf->cpu = cpu;
1773 max_buf->time_start = data->preempt_timestamp;
1774
1775 max_data->saved_latency = tr->max_latency;
1776 max_data->critical_start = data->critical_start;
1777 max_data->critical_end = data->critical_end;
1778
1779 strncpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
1780 max_data->pid = tsk->pid;
1781 /*
1782 * If tsk == current, then use current_uid(), as that does not use
1783 * RCU. The irq tracer can be called out of RCU scope.
1784 */
1785 if (tsk == current)
1786 max_data->uid = current_uid();
1787 else
1788 max_data->uid = task_uid(tsk);
1789
1790 max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
1791 max_data->policy = tsk->policy;
1792 max_data->rt_priority = tsk->rt_priority;
1793
1794 /* record this tasks comm */
1795 tracing_record_cmdline(tsk);
1796 latency_fsnotify(tr);
1797}
1798
1799/**
1800 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
1801 * @tr: tracer
1802 * @tsk: the task with the latency
1803 * @cpu: The cpu that initiated the trace.
1804 * @cond_data: User data associated with a conditional snapshot
1805 *
1806 * Flip the buffers between the @tr and the max_tr and record information
1807 * about which task was the cause of this latency.
1808 */
1809void
1810update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu,
1811 void *cond_data)
1812{
1813 if (tr->stop_count)
1814 return;
1815
1816 WARN_ON_ONCE(!irqs_disabled());
1817
1818 if (!tr->allocated_snapshot) {
1819 /* Only the nop tracer should hit this when disabling */
1820 WARN_ON_ONCE(tr->current_trace != &nop_trace);
1821 return;
1822 }
1823
1824 arch_spin_lock(&tr->max_lock);
1825
1826 /* Inherit the recordable setting from array_buffer */
1827 if (ring_buffer_record_is_set_on(tr->array_buffer.buffer))
1828 ring_buffer_record_on(tr->max_buffer.buffer);
1829 else
1830 ring_buffer_record_off(tr->max_buffer.buffer);
1831
1832#ifdef CONFIG_TRACER_SNAPSHOT
1833 if (tr->cond_snapshot && !tr->cond_snapshot->update(tr, cond_data))
1834 goto out_unlock;
1835#endif
1836 swap(tr->array_buffer.buffer, tr->max_buffer.buffer);
1837
1838 __update_max_tr(tr, tsk, cpu);
1839
1840 out_unlock:
1841 arch_spin_unlock(&tr->max_lock);
1842}
1843
1844/**
1845 * update_max_tr_single - only copy one trace over, and reset the rest
1846 * @tr: tracer
1847 * @tsk: task with the latency
1848 * @cpu: the cpu of the buffer to copy.
1849 *
1850 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
1851 */
1852void
1853update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
1854{
1855 int ret;
1856
1857 if (tr->stop_count)
1858 return;
1859
1860 WARN_ON_ONCE(!irqs_disabled());
1861 if (!tr->allocated_snapshot) {
1862 /* Only the nop tracer should hit this when disabling */
1863 WARN_ON_ONCE(tr->current_trace != &nop_trace);
1864 return;
1865 }
1866
1867 arch_spin_lock(&tr->max_lock);
1868
1869 ret = ring_buffer_swap_cpu(tr->max_buffer.buffer, tr->array_buffer.buffer, cpu);
1870
1871 if (ret == -EBUSY) {
1872 /*
1873 * We failed to swap the buffer due to a commit taking
1874 * place on this CPU. We fail to record, but we reset
1875 * the max trace buffer (no one writes directly to it)
1876 * and flag that it failed.
1877 */
1878 trace_array_printk_buf(tr->max_buffer.buffer, _THIS_IP_,
1879 "Failed to swap buffers due to commit in progress\n");
1880 }
1881
1882 WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);
1883
1884 __update_max_tr(tr, tsk, cpu);
1885 arch_spin_unlock(&tr->max_lock);
1886}
1887#endif /* CONFIG_TRACER_MAX_TRACE */
1888
1889static int wait_on_pipe(struct trace_iterator *iter, int full)
1890{
1891 /* Iterators are static, they should be filled or empty */
1892 if (trace_buffer_iter(iter, iter->cpu_file))
1893 return 0;
1894
1895 return ring_buffer_wait(iter->array_buffer->buffer, iter->cpu_file,
1896 full);
1897}
1898
1899#ifdef CONFIG_FTRACE_STARTUP_TEST
1900static bool selftests_can_run;
1901
1902struct trace_selftests {
1903 struct list_head list;
1904 struct tracer *type;
1905};
1906
1907static LIST_HEAD(postponed_selftests);
1908
1909static int save_selftest(struct tracer *type)
1910{
1911 struct trace_selftests *selftest;
1912
1913 selftest = kmalloc(sizeof(*selftest), GFP_KERNEL);
1914 if (!selftest)
1915 return -ENOMEM;
1916
1917 selftest->type = type;
1918 list_add(&selftest->list, &postponed_selftests);
1919 return 0;
1920}
1921
1922static int run_tracer_selftest(struct tracer *type)
1923{
1924 struct trace_array *tr = &global_trace;
1925 struct tracer *saved_tracer = tr->current_trace;
1926 int ret;
1927
1928 if (!type->selftest || tracing_selftest_disabled)
1929 return 0;
1930
1931 /*
1932 * If a tracer registers early in boot up (before scheduling is
1933 * initialized and such), then do not run its selftests yet.
1934 * Instead, run it a little later in the boot process.
1935 */
1936 if (!selftests_can_run)
1937 return save_selftest(type);
1938
1939 if (!tracing_is_on()) {
1940 pr_warn("Selftest for tracer %s skipped due to tracing disabled\n",
1941 type->name);
1942 return 0;
1943 }
1944
1945 /*
1946 * Run a selftest on this tracer.
1947 * Here we reset the trace buffer, and set the current
1948 * tracer to be this tracer. The tracer can then run some
1949 * internal tracing to verify that everything is in order.
1950 * If we fail, we do not register this tracer.
1951 */
1952 tracing_reset_online_cpus(&tr->array_buffer);
1953
1954 tr->current_trace = type;
1955
1956#ifdef CONFIG_TRACER_MAX_TRACE
1957 if (type->use_max_tr) {
1958 /* If we expanded the buffers, make sure the max is expanded too */
1959 if (ring_buffer_expanded)
1960 ring_buffer_resize(tr->max_buffer.buffer, trace_buf_size,
1961 RING_BUFFER_ALL_CPUS);
1962 tr->allocated_snapshot = true;
1963 }
1964#endif
1965
1966 /* the test is responsible for initializing and enabling */
1967 pr_info("Testing tracer %s: ", type->name);
1968 ret = type->selftest(type, tr);
1969 /* the test is responsible for resetting too */
1970 tr->current_trace = saved_tracer;
1971 if (ret) {
1972 printk(KERN_CONT "FAILED!\n");
1973 /* Add the warning after printing 'FAILED' */
1974 WARN_ON(1);
1975 return -1;
1976 }
1977 /* Only reset on passing, to avoid touching corrupted buffers */
1978 tracing_reset_online_cpus(&tr->array_buffer);
1979
1980#ifdef CONFIG_TRACER_MAX_TRACE
1981 if (type->use_max_tr) {
1982 tr->allocated_snapshot = false;
1983
1984 /* Shrink the max buffer again */
1985 if (ring_buffer_expanded)
1986 ring_buffer_resize(tr->max_buffer.buffer, 1,
1987 RING_BUFFER_ALL_CPUS);
1988 }
1989#endif
1990
1991 printk(KERN_CONT "PASSED\n");
1992 return 0;
1993}
1994
1995static __init int init_trace_selftests(void)
1996{
1997 struct trace_selftests *p, *n;
1998 struct tracer *t, **last;
1999 int ret;
2000
2001 selftests_can_run = true;
2002
2003 mutex_lock(&trace_types_lock);
2004
2005 if (list_empty(&postponed_selftests))
2006 goto out;
2007
2008 pr_info("Running postponed tracer tests:\n");
2009
2010 tracing_selftest_running = true;
2011 list_for_each_entry_safe(p, n, &postponed_selftests, list) {
2012 /* This loop can take minutes when sanitizers are enabled, so
2013 * lets make sure we allow RCU processing.
2014 */
2015 cond_resched();
2016 ret = run_tracer_selftest(p->type);
2017 /* If the test fails, then warn and remove from available_tracers */
2018 if (ret < 0) {
2019 WARN(1, "tracer: %s failed selftest, disabling\n",
2020 p->type->name);
2021 last = &trace_types;
2022 for (t = trace_types; t; t = t->next) {
2023 if (t == p->type) {
2024 *last = t->next;
2025 break;
2026 }
2027 last = &t->next;
2028 }
2029 }
2030 list_del(&p->list);
2031 kfree(p);
2032 }
2033 tracing_selftest_running = false;
2034
2035 out:
2036 mutex_unlock(&trace_types_lock);
2037
2038 return 0;
2039}
2040core_initcall(init_trace_selftests);
2041#else
2042static inline int run_tracer_selftest(struct tracer *type)
2043{
2044 return 0;
2045}
2046#endif /* CONFIG_FTRACE_STARTUP_TEST */
2047
2048static void add_tracer_options(struct trace_array *tr, struct tracer *t);
2049
2050static void __init apply_trace_boot_options(void);
2051
2052/**
2053 * register_tracer - register a tracer with the ftrace system.
2054 * @type: the plugin for the tracer
2055 *
2056 * Register a new plugin tracer.
2057 */
2058int __init register_tracer(struct tracer *type)
2059{
2060 struct tracer *t;
2061 int ret = 0;
2062
2063 if (!type->name) {
2064 pr_info("Tracer must have a name\n");
2065 return -1;
2066 }
2067
2068 if (strlen(type->name) >= MAX_TRACER_SIZE) {
2069 pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE);
2070 return -1;
2071 }
2072
2073 if (security_locked_down(LOCKDOWN_TRACEFS)) {
2074 pr_warn("Can not register tracer %s due to lockdown\n",
2075 type->name);
2076 return -EPERM;
2077 }
2078
2079 mutex_lock(&trace_types_lock);
2080
2081 tracing_selftest_running = true;
2082
2083 for (t = trace_types; t; t = t->next) {
2084 if (strcmp(type->name, t->name) == 0) {
2085 /* already found */
2086 pr_info("Tracer %s already registered\n",
2087 type->name);
2088 ret = -1;
2089 goto out;
2090 }
2091 }
2092
2093 if (!type->set_flag)
2094 type->set_flag = &dummy_set_flag;
2095 if (!type->flags) {
2096 /*allocate a dummy tracer_flags*/
2097 type->flags = kmalloc(sizeof(*type->flags), GFP_KERNEL);
2098 if (!type->flags) {
2099 ret = -ENOMEM;
2100 goto out;
2101 }
2102 type->flags->val = 0;
2103 type->flags->opts = dummy_tracer_opt;
2104 } else
2105 if (!type->flags->opts)
2106 type->flags->opts = dummy_tracer_opt;
2107
2108 /* store the tracer for __set_tracer_option */
2109 type->flags->trace = type;
2110
2111 ret = run_tracer_selftest(type);
2112 if (ret < 0)
2113 goto out;
2114
2115 type->next = trace_types;
2116 trace_types = type;
2117 add_tracer_options(&global_trace, type);
2118
2119 out:
2120 tracing_selftest_running = false;
2121 mutex_unlock(&trace_types_lock);
2122
2123 if (ret || !default_bootup_tracer)
2124 goto out_unlock;
2125
2126 if (strncmp(default_bootup_tracer, type->name, MAX_TRACER_SIZE))
2127 goto out_unlock;
2128
2129 printk(KERN_INFO "Starting tracer '%s'\n", type->name);
2130 /* Do we want this tracer to start on bootup? */
2131 tracing_set_tracer(&global_trace, type->name);
2132 default_bootup_tracer = NULL;
2133
2134 apply_trace_boot_options();
2135
2136 /* disable other selftests, since this will break it. */
2137 disable_tracing_selftest("running a tracer");
2138
2139 out_unlock:
2140 return ret;
2141}
2142
2143static void tracing_reset_cpu(struct array_buffer *buf, int cpu)
2144{
2145 struct trace_buffer *buffer = buf->buffer;
2146
2147 if (!buffer)
2148 return;
2149
2150 ring_buffer_record_disable(buffer);
2151
2152 /* Make sure all commits have finished */
2153 synchronize_rcu();
2154 ring_buffer_reset_cpu(buffer, cpu);
2155
2156 ring_buffer_record_enable(buffer);
2157}
2158
2159void tracing_reset_online_cpus(struct array_buffer *buf)
2160{
2161 struct trace_buffer *buffer = buf->buffer;
2162
2163 if (!buffer)
2164 return;
2165
2166 ring_buffer_record_disable(buffer);
2167
2168 /* Make sure all commits have finished */
2169 synchronize_rcu();
2170
2171 buf->time_start = buffer_ftrace_now(buf, buf->cpu);
2172
2173 ring_buffer_reset_online_cpus(buffer);
2174
2175 ring_buffer_record_enable(buffer);
2176}
2177
2178/* Must have trace_types_lock held */
2179void tracing_reset_all_online_cpus(void)
2180{
2181 struct trace_array *tr;
2182
2183 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
2184 if (!tr->clear_trace)
2185 continue;
2186 tr->clear_trace = false;
2187 tracing_reset_online_cpus(&tr->array_buffer);
2188#ifdef CONFIG_TRACER_MAX_TRACE
2189 tracing_reset_online_cpus(&tr->max_buffer);
2190#endif
2191 }
2192}
2193
2194/*
2195 * The tgid_map array maps from pid to tgid; i.e. the value stored at index i
2196 * is the tgid last observed corresponding to pid=i.
2197 */
2198static int *tgid_map;
2199
2200/* The maximum valid index into tgid_map. */
2201static size_t tgid_map_max;
2202
2203#define SAVED_CMDLINES_DEFAULT 128
2204#define NO_CMDLINE_MAP UINT_MAX
2205static arch_spinlock_t trace_cmdline_lock = __ARCH_SPIN_LOCK_UNLOCKED;
2206struct saved_cmdlines_buffer {
2207 unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
2208 unsigned *map_cmdline_to_pid;
2209 unsigned cmdline_num;
2210 int cmdline_idx;
2211 char *saved_cmdlines;
2212};
2213static struct saved_cmdlines_buffer *savedcmd;
2214
2215static inline char *get_saved_cmdlines(int idx)
2216{
2217 return &savedcmd->saved_cmdlines[idx * TASK_COMM_LEN];
2218}
2219
2220static inline void set_cmdline(int idx, const char *cmdline)
2221{
2222 strncpy(get_saved_cmdlines(idx), cmdline, TASK_COMM_LEN);
2223}
2224
2225static int allocate_cmdlines_buffer(unsigned int val,
2226 struct saved_cmdlines_buffer *s)
2227{
2228 s->map_cmdline_to_pid = kmalloc_array(val,
2229 sizeof(*s->map_cmdline_to_pid),
2230 GFP_KERNEL);
2231 if (!s->map_cmdline_to_pid)
2232 return -ENOMEM;
2233
2234 s->saved_cmdlines = kmalloc_array(TASK_COMM_LEN, val, GFP_KERNEL);
2235 if (!s->saved_cmdlines) {
2236 kfree(s->map_cmdline_to_pid);
2237 return -ENOMEM;
2238 }
2239
2240 s->cmdline_idx = 0;
2241 s->cmdline_num = val;
2242 memset(&s->map_pid_to_cmdline, NO_CMDLINE_MAP,
2243 sizeof(s->map_pid_to_cmdline));
2244 memset(s->map_cmdline_to_pid, NO_CMDLINE_MAP,
2245 val * sizeof(*s->map_cmdline_to_pid));
2246
2247 return 0;
2248}
2249
2250static int trace_create_savedcmd(void)
2251{
2252 int ret;
2253
2254 savedcmd = kmalloc(sizeof(*savedcmd), GFP_KERNEL);
2255 if (!savedcmd)
2256 return -ENOMEM;
2257
2258 ret = allocate_cmdlines_buffer(SAVED_CMDLINES_DEFAULT, savedcmd);
2259 if (ret < 0) {
2260 kfree(savedcmd);
2261 savedcmd = NULL;
2262 return -ENOMEM;
2263 }
2264
2265 return 0;
2266}
2267
2268int is_tracing_stopped(void)
2269{
2270 return global_trace.stop_count;
2271}
2272
2273/**
2274 * tracing_start - quick start of the tracer
2275 *
2276 * If tracing is enabled but was stopped by tracing_stop,
2277 * this will start the tracer back up.
2278 */
2279void tracing_start(void)
2280{
2281 struct trace_buffer *buffer;
2282 unsigned long flags;
2283
2284 if (tracing_disabled)
2285 return;
2286
2287 raw_spin_lock_irqsave(&global_trace.start_lock, flags);
2288 if (--global_trace.stop_count) {
2289 if (global_trace.stop_count < 0) {
2290 /* Someone screwed up their debugging */
2291 WARN_ON_ONCE(1);
2292 global_trace.stop_count = 0;
2293 }
2294 goto out;
2295 }
2296
2297 /* Prevent the buffers from switching */
2298 arch_spin_lock(&global_trace.max_lock);
2299
2300 buffer = global_trace.array_buffer.buffer;
2301 if (buffer)
2302 ring_buffer_record_enable(buffer);
2303
2304#ifdef CONFIG_TRACER_MAX_TRACE
2305 buffer = global_trace.max_buffer.buffer;
2306 if (buffer)
2307 ring_buffer_record_enable(buffer);
2308#endif
2309
2310 arch_spin_unlock(&global_trace.max_lock);
2311
2312 out:
2313 raw_spin_unlock_irqrestore(&global_trace.start_lock, flags);
2314}
2315
2316static void tracing_start_tr(struct trace_array *tr)
2317{
2318 struct trace_buffer *buffer;
2319 unsigned long flags;
2320
2321 if (tracing_disabled)
2322 return;
2323
2324 /* If global, we need to also start the max tracer */
2325 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
2326 return tracing_start();
2327
2328 raw_spin_lock_irqsave(&tr->start_lock, flags);
2329
2330 if (--tr->stop_count) {
2331 if (tr->stop_count < 0) {
2332 /* Someone screwed up their debugging */
2333 WARN_ON_ONCE(1);
2334 tr->stop_count = 0;
2335 }
2336 goto out;
2337 }
2338
2339 buffer = tr->array_buffer.buffer;
2340 if (buffer)
2341 ring_buffer_record_enable(buffer);
2342
2343 out:
2344 raw_spin_unlock_irqrestore(&tr->start_lock, flags);
2345}
2346
2347/**
2348 * tracing_stop - quick stop of the tracer
2349 *
2350 * Light weight way to stop tracing. Use in conjunction with
2351 * tracing_start.
2352 */
2353void tracing_stop(void)
2354{
2355 struct trace_buffer *buffer;
2356 unsigned long flags;
2357
2358 raw_spin_lock_irqsave(&global_trace.start_lock, flags);
2359 if (global_trace.stop_count++)
2360 goto out;
2361
2362 /* Prevent the buffers from switching */
2363 arch_spin_lock(&global_trace.max_lock);
2364
2365 buffer = global_trace.array_buffer.buffer;
2366 if (buffer)
2367 ring_buffer_record_disable(buffer);
2368
2369#ifdef CONFIG_TRACER_MAX_TRACE
2370 buffer = global_trace.max_buffer.buffer;
2371 if (buffer)
2372 ring_buffer_record_disable(buffer);
2373#endif
2374
2375 arch_spin_unlock(&global_trace.max_lock);
2376
2377 out:
2378 raw_spin_unlock_irqrestore(&global_trace.start_lock, flags);
2379}
2380
2381static void tracing_stop_tr(struct trace_array *tr)
2382{
2383 struct trace_buffer *buffer;
2384 unsigned long flags;
2385
2386 /* If global, we need to also stop the max tracer */
2387 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
2388 return tracing_stop();
2389
2390 raw_spin_lock_irqsave(&tr->start_lock, flags);
2391 if (tr->stop_count++)
2392 goto out;
2393
2394 buffer = tr->array_buffer.buffer;
2395 if (buffer)
2396 ring_buffer_record_disable(buffer);
2397
2398 out:
2399 raw_spin_unlock_irqrestore(&tr->start_lock, flags);
2400}
2401
2402static int trace_save_cmdline(struct task_struct *tsk)
2403{
2404 unsigned tpid, idx;
2405
2406 /* treat recording of idle task as a success */
2407 if (!tsk->pid)
2408 return 1;
2409
2410 tpid = tsk->pid & (PID_MAX_DEFAULT - 1);
2411
2412 /*
2413 * It's not the end of the world if we don't get
2414 * the lock, but we also don't want to spin
2415 * nor do we want to disable interrupts,
2416 * so if we miss here, then better luck next time.
2417 */
2418 if (!arch_spin_trylock(&trace_cmdline_lock))
2419 return 0;
2420
2421 idx = savedcmd->map_pid_to_cmdline[tpid];
2422 if (idx == NO_CMDLINE_MAP) {
2423 idx = (savedcmd->cmdline_idx + 1) % savedcmd->cmdline_num;
2424
2425 savedcmd->map_pid_to_cmdline[tpid] = idx;
2426 savedcmd->cmdline_idx = idx;
2427 }
2428
2429 savedcmd->map_cmdline_to_pid[idx] = tsk->pid;
2430 set_cmdline(idx, tsk->comm);
2431
2432 arch_spin_unlock(&trace_cmdline_lock);
2433
2434 return 1;
2435}
2436
2437static void __trace_find_cmdline(int pid, char comm[])
2438{
2439 unsigned map;
2440 int tpid;
2441
2442 if (!pid) {
2443 strcpy(comm, "<idle>");
2444 return;
2445 }
2446
2447 if (WARN_ON_ONCE(pid < 0)) {
2448 strcpy(comm, "<XXX>");
2449 return;
2450 }
2451
2452 tpid = pid & (PID_MAX_DEFAULT - 1);
2453 map = savedcmd->map_pid_to_cmdline[tpid];
2454 if (map != NO_CMDLINE_MAP) {
2455 tpid = savedcmd->map_cmdline_to_pid[map];
2456 if (tpid == pid) {
2457 strlcpy(comm, get_saved_cmdlines(map), TASK_COMM_LEN);
2458 return;
2459 }
2460 }
2461 strcpy(comm, "<...>");
2462}
2463
2464void trace_find_cmdline(int pid, char comm[])
2465{
2466 preempt_disable();
2467 arch_spin_lock(&trace_cmdline_lock);
2468
2469 __trace_find_cmdline(pid, comm);
2470
2471 arch_spin_unlock(&trace_cmdline_lock);
2472 preempt_enable();
2473}
2474
2475static int *trace_find_tgid_ptr(int pid)
2476{
2477 /*
2478 * Pairs with the smp_store_release in set_tracer_flag() to ensure that
2479 * if we observe a non-NULL tgid_map then we also observe the correct
2480 * tgid_map_max.
2481 */
2482 int *map = smp_load_acquire(&tgid_map);
2483
2484 if (unlikely(!map || pid > tgid_map_max))
2485 return NULL;
2486
2487 return &map[pid];
2488}
2489
2490int trace_find_tgid(int pid)
2491{
2492 int *ptr = trace_find_tgid_ptr(pid);
2493
2494 return ptr ? *ptr : 0;
2495}
2496
2497static int trace_save_tgid(struct task_struct *tsk)
2498{
2499 int *ptr;
2500
2501 /* treat recording of idle task as a success */
2502 if (!tsk->pid)
2503 return 1;
2504
2505 ptr = trace_find_tgid_ptr(tsk->pid);
2506 if (!ptr)
2507 return 0;
2508
2509 *ptr = tsk->tgid;
2510 return 1;
2511}
2512
2513static bool tracing_record_taskinfo_skip(int flags)
2514{
2515 if (unlikely(!(flags & (TRACE_RECORD_CMDLINE | TRACE_RECORD_TGID))))
2516 return true;
2517 if (!__this_cpu_read(trace_taskinfo_save))
2518 return true;
2519 return false;
2520}
2521
2522/**
2523 * tracing_record_taskinfo - record the task info of a task
2524 *
2525 * @task: task to record
2526 * @flags: TRACE_RECORD_CMDLINE for recording comm
2527 * TRACE_RECORD_TGID for recording tgid
2528 */
2529void tracing_record_taskinfo(struct task_struct *task, int flags)
2530{
2531 bool done;
2532
2533 if (tracing_record_taskinfo_skip(flags))
2534 return;
2535
2536 /*
2537 * Record as much task information as possible. If some fail, continue
2538 * to try to record the others.
2539 */
2540 done = !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(task);
2541 done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(task);
2542
2543 /* If recording any information failed, retry again soon. */
2544 if (!done)
2545 return;
2546
2547 __this_cpu_write(trace_taskinfo_save, false);
2548}
2549
2550/**
2551 * tracing_record_taskinfo_sched_switch - record task info for sched_switch
2552 *
2553 * @prev: previous task during sched_switch
2554 * @next: next task during sched_switch
2555 * @flags: TRACE_RECORD_CMDLINE for recording comm
2556 * TRACE_RECORD_TGID for recording tgid
2557 */
2558void tracing_record_taskinfo_sched_switch(struct task_struct *prev,
2559 struct task_struct *next, int flags)
2560{
2561 bool done;
2562
2563 if (tracing_record_taskinfo_skip(flags))
2564 return;
2565
2566 /*
2567 * Record as much task information as possible. If some fail, continue
2568 * to try to record the others.
2569 */
2570 done = !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(prev);
2571 done &= !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(next);
2572 done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(prev);
2573 done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(next);
2574
2575 /* If recording any information failed, retry again soon. */
2576 if (!done)
2577 return;
2578
2579 __this_cpu_write(trace_taskinfo_save, false);
2580}
2581
2582/* Helpers to record a specific task information */
2583void tracing_record_cmdline(struct task_struct *task)
2584{
2585 tracing_record_taskinfo(task, TRACE_RECORD_CMDLINE);
2586}
2587
2588void tracing_record_tgid(struct task_struct *task)
2589{
2590 tracing_record_taskinfo(task, TRACE_RECORD_TGID);
2591}
2592
2593/*
2594 * Several functions return TRACE_TYPE_PARTIAL_LINE if the trace_seq
2595 * overflowed, and TRACE_TYPE_HANDLED otherwise. This helper function
2596 * simplifies those functions and keeps them in sync.
2597 */
2598enum print_line_t trace_handle_return(struct trace_seq *s)
2599{
2600 return trace_seq_has_overflowed(s) ?
2601 TRACE_TYPE_PARTIAL_LINE : TRACE_TYPE_HANDLED;
2602}
2603EXPORT_SYMBOL_GPL(trace_handle_return);
2604
2605unsigned int tracing_gen_ctx_irq_test(unsigned int irqs_status)
2606{
2607 unsigned int trace_flags = irqs_status;
2608 unsigned int pc;
2609
2610 pc = preempt_count();
2611
2612 if (pc & NMI_MASK)
2613 trace_flags |= TRACE_FLAG_NMI;
2614 if (pc & HARDIRQ_MASK)
2615 trace_flags |= TRACE_FLAG_HARDIRQ;
2616 if (in_serving_softirq())
2617 trace_flags |= TRACE_FLAG_SOFTIRQ;
2618
2619 if (tif_need_resched())
2620 trace_flags |= TRACE_FLAG_NEED_RESCHED;
2621 if (test_preempt_need_resched())
2622 trace_flags |= TRACE_FLAG_PREEMPT_RESCHED;
2623 return (trace_flags << 16) | (pc & 0xff);
2624}
2625
2626struct ring_buffer_event *
2627trace_buffer_lock_reserve(struct trace_buffer *buffer,
2628 int type,
2629 unsigned long len,
2630 unsigned int trace_ctx)
2631{
2632 return __trace_buffer_lock_reserve(buffer, type, len, trace_ctx);
2633}
2634
2635DEFINE_PER_CPU(struct ring_buffer_event *, trace_buffered_event);
2636DEFINE_PER_CPU(int, trace_buffered_event_cnt);
2637static int trace_buffered_event_ref;
2638
2639/**
2640 * trace_buffered_event_enable - enable buffering events
2641 *
2642 * When events are being filtered, it is quicker to use a temporary
2643 * buffer to write the event data into if there's a likely chance
2644 * that it will not be committed. The discard of the ring buffer
2645 * is not as fast as committing, and is much slower than copying
2646 * a commit.
2647 *
2648 * When an event is to be filtered, allocate per cpu buffers to
2649 * write the event data into, and if the event is filtered and discarded
2650 * it is simply dropped, otherwise, the entire data is to be committed
2651 * in one shot.
2652 */
2653void trace_buffered_event_enable(void)
2654{
2655 struct ring_buffer_event *event;
2656 struct page *page;
2657 int cpu;
2658
2659 WARN_ON_ONCE(!mutex_is_locked(&event_mutex));
2660
2661 if (trace_buffered_event_ref++)
2662 return;
2663
2664 for_each_tracing_cpu(cpu) {
2665 page = alloc_pages_node(cpu_to_node(cpu),
2666 GFP_KERNEL | __GFP_NORETRY, 0);
2667 if (!page)
2668 goto failed;
2669
2670 event = page_address(page);
2671 memset(event, 0, sizeof(*event));
2672
2673 per_cpu(trace_buffered_event, cpu) = event;
2674
2675 preempt_disable();
2676 if (cpu == smp_processor_id() &&
2677 __this_cpu_read(trace_buffered_event) !=
2678 per_cpu(trace_buffered_event, cpu))
2679 WARN_ON_ONCE(1);
2680 preempt_enable();
2681 }
2682
2683 return;
2684 failed:
2685 trace_buffered_event_disable();
2686}
2687
2688static void enable_trace_buffered_event(void *data)
2689{
2690 /* Probably not needed, but do it anyway */
2691 smp_rmb();
2692 this_cpu_dec(trace_buffered_event_cnt);
2693}
2694
2695static void disable_trace_buffered_event(void *data)
2696{
2697 this_cpu_inc(trace_buffered_event_cnt);
2698}
2699
2700/**
2701 * trace_buffered_event_disable - disable buffering events
2702 *
2703 * When a filter is removed, it is faster to not use the buffered
2704 * events, and to commit directly into the ring buffer. Free up
2705 * the temp buffers when there are no more users. This requires
2706 * special synchronization with current events.
2707 */
2708void trace_buffered_event_disable(void)
2709{
2710 int cpu;
2711
2712 WARN_ON_ONCE(!mutex_is_locked(&event_mutex));
2713
2714 if (WARN_ON_ONCE(!trace_buffered_event_ref))
2715 return;
2716
2717 if (--trace_buffered_event_ref)
2718 return;
2719
2720 preempt_disable();
2721 /* For each CPU, set the buffer as used. */
2722 smp_call_function_many(tracing_buffer_mask,
2723 disable_trace_buffered_event, NULL, 1);
2724 preempt_enable();
2725
2726 /* Wait for all current users to finish */
2727 synchronize_rcu();
2728
2729 for_each_tracing_cpu(cpu) {
2730 free_page((unsigned long)per_cpu(trace_buffered_event, cpu));
2731 per_cpu(trace_buffered_event, cpu) = NULL;
2732 }
2733 /*
2734 * Make sure trace_buffered_event is NULL before clearing
2735 * trace_buffered_event_cnt.
2736 */
2737 smp_wmb();
2738
2739 preempt_disable();
2740 /* Do the work on each cpu */
2741 smp_call_function_many(tracing_buffer_mask,
2742 enable_trace_buffered_event, NULL, 1);
2743 preempt_enable();
2744}
2745
2746static struct trace_buffer *temp_buffer;
2747
2748struct ring_buffer_event *
2749trace_event_buffer_lock_reserve(struct trace_buffer **current_rb,
2750 struct trace_event_file *trace_file,
2751 int type, unsigned long len,
2752 unsigned int trace_ctx)
2753{
2754 struct ring_buffer_event *entry;
2755 struct trace_array *tr = trace_file->tr;
2756 int val;
2757
2758 *current_rb = tr->array_buffer.buffer;
2759
2760 if (!tr->no_filter_buffering_ref &&
2761 (trace_file->flags & (EVENT_FILE_FL_SOFT_DISABLED | EVENT_FILE_FL_FILTERED)) &&
2762 (entry = this_cpu_read(trace_buffered_event))) {
2763 /*
2764 * Filtering is on, so try to use the per cpu buffer first.
2765 * This buffer will simulate a ring_buffer_event,
2766 * where the type_len is zero and the array[0] will
2767 * hold the full length.
2768 * (see include/linux/ring-buffer.h for details on
2769 * how the ring_buffer_event is structured).
2770 *
2771 * Using a temp buffer during filtering and copying it
2772 * on a matched filter is quicker than writing directly
2773 * into the ring buffer and then discarding it when
2774 * it doesn't match. That is because the discard
2775 * requires several atomic operations to get right.
2776 * Copying on match and doing nothing on a failed match
2777 * is still quicker than no copy on match, but having
2778 * to discard out of the ring buffer on a failed match.
2779 */
2780 int max_len = PAGE_SIZE - struct_size(entry, array, 1);
2781
2782 val = this_cpu_inc_return(trace_buffered_event_cnt);
2783
2784 /*
2785 * Preemption is disabled, but interrupts and NMIs
2786 * can still come in now. If that happens after
2787 * the above increment, then it will have to go
2788 * back to the old method of allocating the event
2789 * on the ring buffer, and if the filter fails, it
2790 * will have to call ring_buffer_discard_commit()
2791 * to remove it.
2792 *
2793 * Need to also check the unlikely case that the
2794 * length is bigger than the temp buffer size.
2795 * If that happens, then the reserve is pretty much
2796 * guaranteed to fail, as the ring buffer currently
2797 * only allows events less than a page. But that may
2798 * change in the future, so let the ring buffer reserve
2799 * handle the failure in that case.
2800 */
2801 if (val == 1 && likely(len <= max_len)) {
2802 trace_event_setup(entry, type, trace_ctx);
2803 entry->array[0] = len;
2804 return entry;
2805 }
2806 this_cpu_dec(trace_buffered_event_cnt);
2807 }
2808
2809 entry = __trace_buffer_lock_reserve(*current_rb, type, len,
2810 trace_ctx);
2811 /*
2812 * If tracing is off, but we have triggers enabled
2813 * we still need to look at the event data. Use the temp_buffer
2814 * to store the trace event for the trigger to use. It's recursive
2815 * safe and will not be recorded anywhere.
2816 */
2817 if (!entry && trace_file->flags & EVENT_FILE_FL_TRIGGER_COND) {
2818 *current_rb = temp_buffer;
2819 entry = __trace_buffer_lock_reserve(*current_rb, type, len,
2820 trace_ctx);
2821 }
2822 return entry;
2823}
2824EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve);
2825
2826static DEFINE_SPINLOCK(tracepoint_iter_lock);
2827static DEFINE_MUTEX(tracepoint_printk_mutex);
2828
2829static void output_printk(struct trace_event_buffer *fbuffer)
2830{
2831 struct trace_event_call *event_call;
2832 struct trace_event_file *file;
2833 struct trace_event *event;
2834 unsigned long flags;
2835 struct trace_iterator *iter = tracepoint_print_iter;
2836
2837 /* We should never get here if iter is NULL */
2838 if (WARN_ON_ONCE(!iter))
2839 return;
2840
2841 event_call = fbuffer->trace_file->event_call;
2842 if (!event_call || !event_call->event.funcs ||
2843 !event_call->event.funcs->trace)
2844 return;
2845
2846 file = fbuffer->trace_file;
2847 if (test_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags) ||
2848 (unlikely(file->flags & EVENT_FILE_FL_FILTERED) &&
2849 !filter_match_preds(file->filter, fbuffer->entry)))
2850 return;
2851
2852 event = &fbuffer->trace_file->event_call->event;
2853
2854 spin_lock_irqsave(&tracepoint_iter_lock, flags);
2855 trace_seq_init(&iter->seq);
2856 iter->ent = fbuffer->entry;
2857 event_call->event.funcs->trace(iter, 0, event);
2858 trace_seq_putc(&iter->seq, 0);
2859 printk("%s", iter->seq.buffer);
2860
2861 spin_unlock_irqrestore(&tracepoint_iter_lock, flags);
2862}
2863
2864int tracepoint_printk_sysctl(struct ctl_table *table, int write,
2865 void *buffer, size_t *lenp,
2866 loff_t *ppos)
2867{
2868 int save_tracepoint_printk;
2869 int ret;
2870
2871 mutex_lock(&tracepoint_printk_mutex);
2872 save_tracepoint_printk = tracepoint_printk;
2873
2874 ret = proc_dointvec(table, write, buffer, lenp, ppos);
2875
2876 /*
2877 * This will force exiting early, as tracepoint_printk
2878 * is always zero when tracepoint_printk_iter is not allocated
2879 */
2880 if (!tracepoint_print_iter)
2881 tracepoint_printk = 0;
2882
2883 if (save_tracepoint_printk == tracepoint_printk)
2884 goto out;
2885
2886 if (tracepoint_printk)
2887 static_key_enable(&tracepoint_printk_key.key);
2888 else
2889 static_key_disable(&tracepoint_printk_key.key);
2890
2891 out:
2892 mutex_unlock(&tracepoint_printk_mutex);
2893
2894 return ret;
2895}
2896
2897void trace_event_buffer_commit(struct trace_event_buffer *fbuffer)
2898{
2899 enum event_trigger_type tt = ETT_NONE;
2900 struct trace_event_file *file = fbuffer->trace_file;
2901
2902 if (__event_trigger_test_discard(file, fbuffer->buffer, fbuffer->event,
2903 fbuffer->entry, &tt))
2904 goto discard;
2905
2906 if (static_key_false(&tracepoint_printk_key.key))
2907 output_printk(fbuffer);
2908
2909 if (static_branch_unlikely(&trace_event_exports_enabled))
2910 ftrace_exports(fbuffer->event, TRACE_EXPORT_EVENT);
2911
2912 trace_buffer_unlock_commit_regs(file->tr, fbuffer->buffer,
2913 fbuffer->event, fbuffer->trace_ctx, fbuffer->regs);
2914
2915discard:
2916 if (tt)
2917 event_triggers_post_call(file, tt);
2918
2919}
2920EXPORT_SYMBOL_GPL(trace_event_buffer_commit);
2921
2922/*
2923 * Skip 3:
2924 *
2925 * trace_buffer_unlock_commit_regs()
2926 * trace_event_buffer_commit()
2927 * trace_event_raw_event_xxx()
2928 */
2929# define STACK_SKIP 3
2930
2931void trace_buffer_unlock_commit_regs(struct trace_array *tr,
2932 struct trace_buffer *buffer,
2933 struct ring_buffer_event *event,
2934 unsigned int trace_ctx,
2935 struct pt_regs *regs)
2936{
2937 __buffer_unlock_commit(buffer, event);
2938
2939 /*
2940 * If regs is not set, then skip the necessary functions.
2941 * Note, we can still get here via blktrace, wakeup tracer
2942 * and mmiotrace, but that's ok if they lose a function or
2943 * two. They are not that meaningful.
2944 */
2945 ftrace_trace_stack(tr, buffer, trace_ctx, regs ? 0 : STACK_SKIP, regs);
2946 ftrace_trace_userstack(tr, buffer, trace_ctx);
2947}
2948
2949/*
2950 * Similar to trace_buffer_unlock_commit_regs() but do not dump stack.
2951 */
2952void
2953trace_buffer_unlock_commit_nostack(struct trace_buffer *buffer,
2954 struct ring_buffer_event *event)
2955{
2956 __buffer_unlock_commit(buffer, event);
2957}
2958
2959void
2960trace_function(struct trace_array *tr, unsigned long ip, unsigned long
2961 parent_ip, unsigned int trace_ctx)
2962{
2963 struct trace_event_call *call = &event_function;
2964 struct trace_buffer *buffer = tr->array_buffer.buffer;
2965 struct ring_buffer_event *event;
2966 struct ftrace_entry *entry;
2967
2968 event = __trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
2969 trace_ctx);
2970 if (!event)
2971 return;
2972 entry = ring_buffer_event_data(event);
2973 entry->ip = ip;
2974 entry->parent_ip = parent_ip;
2975
2976 if (!call_filter_check_discard(call, entry, buffer, event)) {
2977 if (static_branch_unlikely(&trace_function_exports_enabled))
2978 ftrace_exports(event, TRACE_EXPORT_FUNCTION);
2979 __buffer_unlock_commit(buffer, event);
2980 }
2981}
2982
2983#ifdef CONFIG_STACKTRACE
2984
2985/* Allow 4 levels of nesting: normal, softirq, irq, NMI */
2986#define FTRACE_KSTACK_NESTING 4
2987
2988#define FTRACE_KSTACK_ENTRIES (PAGE_SIZE / FTRACE_KSTACK_NESTING)
2989
2990struct ftrace_stack {
2991 unsigned long calls[FTRACE_KSTACK_ENTRIES];
2992};
2993
2994
2995struct ftrace_stacks {
2996 struct ftrace_stack stacks[FTRACE_KSTACK_NESTING];
2997};
2998
2999static DEFINE_PER_CPU(struct ftrace_stacks, ftrace_stacks);
3000static DEFINE_PER_CPU(int, ftrace_stack_reserve);
3001
3002static void __ftrace_trace_stack(struct trace_buffer *buffer,
3003 unsigned int trace_ctx,
3004 int skip, struct pt_regs *regs)
3005{
3006 struct trace_event_call *call = &event_kernel_stack;
3007 struct ring_buffer_event *event;
3008 unsigned int size, nr_entries;
3009 struct ftrace_stack *fstack;
3010 struct stack_entry *entry;
3011 int stackidx;
3012
3013 /*
3014 * Add one, for this function and the call to save_stack_trace()
3015 * If regs is set, then these functions will not be in the way.
3016 */
3017#ifndef CONFIG_UNWINDER_ORC
3018 if (!regs)
3019 skip++;
3020#endif
3021
3022 preempt_disable_notrace();
3023
3024 stackidx = __this_cpu_inc_return(ftrace_stack_reserve) - 1;
3025
3026 /* This should never happen. If it does, yell once and skip */
3027 if (WARN_ON_ONCE(stackidx >= FTRACE_KSTACK_NESTING))
3028 goto out;
3029
3030 /*
3031 * The above __this_cpu_inc_return() is 'atomic' cpu local. An
3032 * interrupt will either see the value pre increment or post
3033 * increment. If the interrupt happens pre increment it will have
3034 * restored the counter when it returns. We just need a barrier to
3035 * keep gcc from moving things around.
3036 */
3037 barrier();
3038
3039 fstack = this_cpu_ptr(ftrace_stacks.stacks) + stackidx;
3040 size = ARRAY_SIZE(fstack->calls);
3041
3042 if (regs) {
3043 nr_entries = stack_trace_save_regs(regs, fstack->calls,
3044 size, skip);
3045 } else {
3046 nr_entries = stack_trace_save(fstack->calls, size, skip);
3047 }
3048
3049 size = nr_entries * sizeof(unsigned long);
3050 event = __trace_buffer_lock_reserve(buffer, TRACE_STACK,
3051 (sizeof(*entry) - sizeof(entry->caller)) + size,
3052 trace_ctx);
3053 if (!event)
3054 goto out;
3055 entry = ring_buffer_event_data(event);
3056
3057 memcpy(&entry->caller, fstack->calls, size);
3058 entry->size = nr_entries;
3059
3060 if (!call_filter_check_discard(call, entry, buffer, event))
3061 __buffer_unlock_commit(buffer, event);
3062
3063 out:
3064 /* Again, don't let gcc optimize things here */
3065 barrier();
3066 __this_cpu_dec(ftrace_stack_reserve);
3067 preempt_enable_notrace();
3068
3069}
3070
3071static inline void ftrace_trace_stack(struct trace_array *tr,
3072 struct trace_buffer *buffer,
3073 unsigned int trace_ctx,
3074 int skip, struct pt_regs *regs)
3075{
3076 if (!(tr->trace_flags & TRACE_ITER_STACKTRACE))
3077 return;
3078
3079 __ftrace_trace_stack(buffer, trace_ctx, skip, regs);
3080}
3081
3082void __trace_stack(struct trace_array *tr, unsigned int trace_ctx,
3083 int skip)
3084{
3085 struct trace_buffer *buffer = tr->array_buffer.buffer;
3086
3087 if (rcu_is_watching()) {
3088 __ftrace_trace_stack(buffer, trace_ctx, skip, NULL);
3089 return;
3090 }
3091
3092 /*
3093 * When an NMI triggers, RCU is enabled via rcu_nmi_enter(),
3094 * but if the above rcu_is_watching() failed, then the NMI
3095 * triggered someplace critical, and rcu_irq_enter() should
3096 * not be called from NMI.
3097 */
3098 if (unlikely(in_nmi()))
3099 return;
3100
3101 rcu_irq_enter_irqson();
3102 __ftrace_trace_stack(buffer, trace_ctx, skip, NULL);
3103 rcu_irq_exit_irqson();
3104}
3105
3106/**
3107 * trace_dump_stack - record a stack back trace in the trace buffer
3108 * @skip: Number of functions to skip (helper handlers)
3109 */
3110void trace_dump_stack(int skip)
3111{
3112 if (tracing_disabled || tracing_selftest_running)
3113 return;
3114
3115#ifndef CONFIG_UNWINDER_ORC
3116 /* Skip 1 to skip this function. */
3117 skip++;
3118#endif
3119 __ftrace_trace_stack(global_trace.array_buffer.buffer,
3120 tracing_gen_ctx(), skip, NULL);
3121}
3122EXPORT_SYMBOL_GPL(trace_dump_stack);
3123
3124#ifdef CONFIG_USER_STACKTRACE_SUPPORT
3125static DEFINE_PER_CPU(int, user_stack_count);
3126
3127static void
3128ftrace_trace_userstack(struct trace_array *tr,
3129 struct trace_buffer *buffer, unsigned int trace_ctx)
3130{
3131 struct trace_event_call *call = &event_user_stack;
3132 struct ring_buffer_event *event;
3133 struct userstack_entry *entry;
3134
3135 if (!(tr->trace_flags & TRACE_ITER_USERSTACKTRACE))
3136 return;
3137
3138 /*
3139 * NMIs can not handle page faults, even with fix ups.
3140 * The save user stack can (and often does) fault.
3141 */
3142 if (unlikely(in_nmi()))
3143 return;
3144
3145 /*
3146 * prevent recursion, since the user stack tracing may
3147 * trigger other kernel events.
3148 */
3149 preempt_disable();
3150 if (__this_cpu_read(user_stack_count))
3151 goto out;
3152
3153 __this_cpu_inc(user_stack_count);
3154
3155 event = __trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
3156 sizeof(*entry), trace_ctx);
3157 if (!event)
3158 goto out_drop_count;
3159 entry = ring_buffer_event_data(event);
3160
3161 entry->tgid = current->tgid;
3162 memset(&entry->caller, 0, sizeof(entry->caller));
3163
3164 stack_trace_save_user(entry->caller, FTRACE_STACK_ENTRIES);
3165 if (!call_filter_check_discard(call, entry, buffer, event))
3166 __buffer_unlock_commit(buffer, event);
3167
3168 out_drop_count:
3169 __this_cpu_dec(user_stack_count);
3170 out:
3171 preempt_enable();
3172}
3173#else /* CONFIG_USER_STACKTRACE_SUPPORT */
3174static void ftrace_trace_userstack(struct trace_array *tr,
3175 struct trace_buffer *buffer,
3176 unsigned int trace_ctx)
3177{
3178}
3179#endif /* !CONFIG_USER_STACKTRACE_SUPPORT */
3180
3181#endif /* CONFIG_STACKTRACE */
3182
3183static inline void
3184func_repeats_set_delta_ts(struct func_repeats_entry *entry,
3185 unsigned long long delta)
3186{
3187 entry->bottom_delta_ts = delta & U32_MAX;
3188 entry->top_delta_ts = (delta >> 32);
3189}
3190
3191void trace_last_func_repeats(struct trace_array *tr,
3192 struct trace_func_repeats *last_info,
3193 unsigned int trace_ctx)
3194{
3195 struct trace_buffer *buffer = tr->array_buffer.buffer;
3196 struct func_repeats_entry *entry;
3197 struct ring_buffer_event *event;
3198 u64 delta;
3199
3200 event = __trace_buffer_lock_reserve(buffer, TRACE_FUNC_REPEATS,
3201 sizeof(*entry), trace_ctx);
3202 if (!event)
3203 return;
3204
3205 delta = ring_buffer_event_time_stamp(buffer, event) -
3206 last_info->ts_last_call;
3207
3208 entry = ring_buffer_event_data(event);
3209 entry->ip = last_info->ip;
3210 entry->parent_ip = last_info->parent_ip;
3211 entry->count = last_info->count;
3212 func_repeats_set_delta_ts(entry, delta);
3213
3214 __buffer_unlock_commit(buffer, event);
3215}
3216
3217/* created for use with alloc_percpu */
3218struct trace_buffer_struct {
3219 int nesting;
3220 char buffer[4][TRACE_BUF_SIZE];
3221};
3222
3223static struct trace_buffer_struct *trace_percpu_buffer;
3224
3225/*
3226 * This allows for lockless recording. If we're nested too deeply, then
3227 * this returns NULL.
3228 */
3229static char *get_trace_buf(void)
3230{
3231 struct trace_buffer_struct *buffer = this_cpu_ptr(trace_percpu_buffer);
3232
3233 if (!buffer || buffer->nesting >= 4)
3234 return NULL;
3235
3236 buffer->nesting++;
3237
3238 /* Interrupts must see nesting incremented before we use the buffer */
3239 barrier();
3240 return &buffer->buffer[buffer->nesting - 1][0];
3241}
3242
3243static void put_trace_buf(void)
3244{
3245 /* Don't let the decrement of nesting leak before this */
3246 barrier();
3247 this_cpu_dec(trace_percpu_buffer->nesting);
3248}
3249
3250static int alloc_percpu_trace_buffer(void)
3251{
3252 struct trace_buffer_struct *buffers;
3253
3254 if (trace_percpu_buffer)
3255 return 0;
3256
3257 buffers = alloc_percpu(struct trace_buffer_struct);
3258 if (MEM_FAIL(!buffers, "Could not allocate percpu trace_printk buffer"))
3259 return -ENOMEM;
3260
3261 trace_percpu_buffer = buffers;
3262 return 0;
3263}
3264
3265static int buffers_allocated;
3266
3267void trace_printk_init_buffers(void)
3268{
3269 if (buffers_allocated)
3270 return;
3271
3272 if (alloc_percpu_trace_buffer())
3273 return;
3274
3275 /* trace_printk() is for debug use only. Don't use it in production. */
3276
3277 pr_warn("\n");
3278 pr_warn("**********************************************************\n");
3279 pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
3280 pr_warn("** **\n");
3281 pr_warn("** trace_printk() being used. Allocating extra memory. **\n");
3282 pr_warn("** **\n");
3283 pr_warn("** This means that this is a DEBUG kernel and it is **\n");
3284 pr_warn("** unsafe for production use. **\n");
3285 pr_warn("** **\n");
3286 pr_warn("** If you see this message and you are not debugging **\n");
3287 pr_warn("** the kernel, report this immediately to your vendor! **\n");
3288 pr_warn("** **\n");
3289 pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
3290 pr_warn("**********************************************************\n");
3291
3292 /* Expand the buffers to set size */
3293 tracing_update_buffers();
3294
3295 buffers_allocated = 1;
3296
3297 /*
3298 * trace_printk_init_buffers() can be called by modules.
3299 * If that happens, then we need to start cmdline recording
3300 * directly here. If the global_trace.buffer is already
3301 * allocated here, then this was called by module code.
3302 */
3303 if (global_trace.array_buffer.buffer)
3304 tracing_start_cmdline_record();
3305}
3306EXPORT_SYMBOL_GPL(trace_printk_init_buffers);
3307
3308void trace_printk_start_comm(void)
3309{
3310 /* Start tracing comms if trace printk is set */
3311 if (!buffers_allocated)
3312 return;
3313 tracing_start_cmdline_record();
3314}
3315
3316static void trace_printk_start_stop_comm(int enabled)
3317{
3318 if (!buffers_allocated)
3319 return;
3320
3321 if (enabled)
3322 tracing_start_cmdline_record();
3323 else
3324 tracing_stop_cmdline_record();
3325}
3326
3327/**
3328 * trace_vbprintk - write binary msg to tracing buffer
3329 * @ip: The address of the caller
3330 * @fmt: The string format to write to the buffer
3331 * @args: Arguments for @fmt
3332 */
3333int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
3334{
3335 struct trace_event_call *call = &event_bprint;
3336 struct ring_buffer_event *event;
3337 struct trace_buffer *buffer;
3338 struct trace_array *tr = &global_trace;
3339 struct bprint_entry *entry;
3340 unsigned int trace_ctx;
3341 char *tbuffer;
3342 int len = 0, size;
3343
3344 if (unlikely(tracing_selftest_running || tracing_disabled))
3345 return 0;
3346
3347 /* Don't pollute graph traces with trace_vprintk internals */
3348 pause_graph_tracing();
3349
3350 trace_ctx = tracing_gen_ctx();
3351 preempt_disable_notrace();
3352
3353 tbuffer = get_trace_buf();
3354 if (!tbuffer) {
3355 len = 0;
3356 goto out_nobuffer;
3357 }
3358
3359 len = vbin_printf((u32 *)tbuffer, TRACE_BUF_SIZE/sizeof(int), fmt, args);
3360
3361 if (len > TRACE_BUF_SIZE/sizeof(int) || len < 0)
3362 goto out_put;
3363
3364 size = sizeof(*entry) + sizeof(u32) * len;
3365 buffer = tr->array_buffer.buffer;
3366 ring_buffer_nest_start(buffer);
3367 event = __trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
3368 trace_ctx);
3369 if (!event)
3370 goto out;
3371 entry = ring_buffer_event_data(event);
3372 entry->ip = ip;
3373 entry->fmt = fmt;
3374
3375 memcpy(entry->buf, tbuffer, sizeof(u32) * len);
3376 if (!call_filter_check_discard(call, entry, buffer, event)) {
3377 __buffer_unlock_commit(buffer, event);
3378 ftrace_trace_stack(tr, buffer, trace_ctx, 6, NULL);
3379 }
3380
3381out:
3382 ring_buffer_nest_end(buffer);
3383out_put:
3384 put_trace_buf();
3385
3386out_nobuffer:
3387 preempt_enable_notrace();
3388 unpause_graph_tracing();
3389
3390 return len;
3391}
3392EXPORT_SYMBOL_GPL(trace_vbprintk);
3393
3394__printf(3, 0)
3395static int
3396__trace_array_vprintk(struct trace_buffer *buffer,
3397 unsigned long ip, const char *fmt, va_list args)
3398{
3399 struct trace_event_call *call = &event_print;
3400 struct ring_buffer_event *event;
3401 int len = 0, size;
3402 struct print_entry *entry;
3403 unsigned int trace_ctx;
3404 char *tbuffer;
3405
3406 if (tracing_disabled || tracing_selftest_running)
3407 return 0;
3408
3409 /* Don't pollute graph traces with trace_vprintk internals */
3410 pause_graph_tracing();
3411
3412 trace_ctx = tracing_gen_ctx();
3413 preempt_disable_notrace();
3414
3415
3416 tbuffer = get_trace_buf();
3417 if (!tbuffer) {
3418 len = 0;
3419 goto out_nobuffer;
3420 }
3421
3422 len = vscnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args);
3423
3424 size = sizeof(*entry) + len + 1;
3425 ring_buffer_nest_start(buffer);
3426 event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
3427 trace_ctx);
3428 if (!event)
3429 goto out;
3430 entry = ring_buffer_event_data(event);
3431 entry->ip = ip;
3432
3433 memcpy(&entry->buf, tbuffer, len + 1);
3434 if (!call_filter_check_discard(call, entry, buffer, event)) {
3435 __buffer_unlock_commit(buffer, event);
3436 ftrace_trace_stack(&global_trace, buffer, trace_ctx, 6, NULL);
3437 }
3438
3439out:
3440 ring_buffer_nest_end(buffer);
3441 put_trace_buf();
3442
3443out_nobuffer:
3444 preempt_enable_notrace();
3445 unpause_graph_tracing();
3446
3447 return len;
3448}
3449
3450__printf(3, 0)
3451int trace_array_vprintk(struct trace_array *tr,
3452 unsigned long ip, const char *fmt, va_list args)
3453{
3454 return __trace_array_vprintk(tr->array_buffer.buffer, ip, fmt, args);
3455}
3456
3457/**
3458 * trace_array_printk - Print a message to a specific instance
3459 * @tr: The instance trace_array descriptor
3460 * @ip: The instruction pointer that this is called from.
3461 * @fmt: The format to print (printf format)
3462 *
3463 * If a subsystem sets up its own instance, they have the right to
3464 * printk strings into their tracing instance buffer using this
3465 * function. Note, this function will not write into the top level
3466 * buffer (use trace_printk() for that), as writing into the top level
3467 * buffer should only have events that can be individually disabled.
3468 * trace_printk() is only used for debugging a kernel, and should not
3469 * be ever incorporated in normal use.
3470 *
3471 * trace_array_printk() can be used, as it will not add noise to the
3472 * top level tracing buffer.
3473 *
3474 * Note, trace_array_init_printk() must be called on @tr before this
3475 * can be used.
3476 */
3477__printf(3, 0)
3478int trace_array_printk(struct trace_array *tr,
3479 unsigned long ip, const char *fmt, ...)
3480{
3481 int ret;
3482 va_list ap;
3483
3484 if (!tr)
3485 return -ENOENT;
3486
3487 /* This is only allowed for created instances */
3488 if (tr == &global_trace)
3489 return 0;
3490
3491 if (!(tr->trace_flags & TRACE_ITER_PRINTK))
3492 return 0;
3493
3494 va_start(ap, fmt);
3495 ret = trace_array_vprintk(tr, ip, fmt, ap);
3496 va_end(ap);
3497 return ret;
3498}
3499EXPORT_SYMBOL_GPL(trace_array_printk);
3500
3501/**
3502 * trace_array_init_printk - Initialize buffers for trace_array_printk()
3503 * @tr: The trace array to initialize the buffers for
3504 *
3505 * As trace_array_printk() only writes into instances, they are OK to
3506 * have in the kernel (unlike trace_printk()). This needs to be called
3507 * before trace_array_printk() can be used on a trace_array.
3508 */
3509int trace_array_init_printk(struct trace_array *tr)
3510{
3511 if (!tr)
3512 return -ENOENT;
3513
3514 /* This is only allowed for created instances */
3515 if (tr == &global_trace)
3516 return -EINVAL;
3517
3518 return alloc_percpu_trace_buffer();
3519}
3520EXPORT_SYMBOL_GPL(trace_array_init_printk);
3521
3522__printf(3, 4)
3523int trace_array_printk_buf(struct trace_buffer *buffer,
3524 unsigned long ip, const char *fmt, ...)
3525{
3526 int ret;
3527 va_list ap;
3528
3529 if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
3530 return 0;
3531
3532 va_start(ap, fmt);
3533 ret = __trace_array_vprintk(buffer, ip, fmt, ap);
3534 va_end(ap);
3535 return ret;
3536}
3537
3538__printf(2, 0)
3539int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
3540{
3541 return trace_array_vprintk(&global_trace, ip, fmt, args);
3542}
3543EXPORT_SYMBOL_GPL(trace_vprintk);
3544
3545static void trace_iterator_increment(struct trace_iterator *iter)
3546{
3547 struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, iter->cpu);
3548
3549 iter->idx++;
3550 if (buf_iter)
3551 ring_buffer_iter_advance(buf_iter);
3552}
3553
3554static struct trace_entry *
3555peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts,
3556 unsigned long *lost_events)
3557{
3558 struct ring_buffer_event *event;
3559 struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, cpu);
3560
3561 if (buf_iter) {
3562 event = ring_buffer_iter_peek(buf_iter, ts);
3563 if (lost_events)
3564 *lost_events = ring_buffer_iter_dropped(buf_iter) ?
3565 (unsigned long)-1 : 0;
3566 } else {
3567 event = ring_buffer_peek(iter->array_buffer->buffer, cpu, ts,
3568 lost_events);
3569 }
3570
3571 if (event) {
3572 iter->ent_size = ring_buffer_event_length(event);
3573 return ring_buffer_event_data(event);
3574 }
3575 iter->ent_size = 0;
3576 return NULL;
3577}
3578
3579static struct trace_entry *
3580__find_next_entry(struct trace_iterator *iter, int *ent_cpu,
3581 unsigned long *missing_events, u64 *ent_ts)
3582{
3583 struct trace_buffer *buffer = iter->array_buffer->buffer;
3584 struct trace_entry *ent, *next = NULL;
3585 unsigned long lost_events = 0, next_lost = 0;
3586 int cpu_file = iter->cpu_file;
3587 u64 next_ts = 0, ts;
3588 int next_cpu = -1;
3589 int next_size = 0;
3590 int cpu;
3591
3592 /*
3593 * If we are in a per_cpu trace file, don't bother by iterating over
3594 * all cpu and peek directly.
3595 */
3596 if (cpu_file > RING_BUFFER_ALL_CPUS) {
3597 if (ring_buffer_empty_cpu(buffer, cpu_file))
3598 return NULL;
3599 ent = peek_next_entry(iter, cpu_file, ent_ts, missing_events);
3600 if (ent_cpu)
3601 *ent_cpu = cpu_file;
3602
3603 return ent;
3604 }
3605
3606 for_each_tracing_cpu(cpu) {
3607
3608 if (ring_buffer_empty_cpu(buffer, cpu))
3609 continue;
3610
3611 ent = peek_next_entry(iter, cpu, &ts, &lost_events);
3612
3613 /*
3614 * Pick the entry with the smallest timestamp:
3615 */
3616 if (ent && (!next || ts < next_ts)) {
3617 next = ent;
3618 next_cpu = cpu;
3619 next_ts = ts;
3620 next_lost = lost_events;
3621 next_size = iter->ent_size;
3622 }
3623 }
3624
3625 iter->ent_size = next_size;
3626
3627 if (ent_cpu)
3628 *ent_cpu = next_cpu;
3629
3630 if (ent_ts)
3631 *ent_ts = next_ts;
3632
3633 if (missing_events)
3634 *missing_events = next_lost;
3635
3636 return next;
3637}
3638
3639#define STATIC_FMT_BUF_SIZE 128
3640static char static_fmt_buf[STATIC_FMT_BUF_SIZE];
3641
3642static char *trace_iter_expand_format(struct trace_iterator *iter)
3643{
3644 char *tmp;
3645
3646 /*
3647 * iter->tr is NULL when used with tp_printk, which makes
3648 * this get called where it is not safe to call krealloc().
3649 */
3650 if (!iter->tr || iter->fmt == static_fmt_buf)
3651 return NULL;
3652
3653 tmp = krealloc(iter->fmt, iter->fmt_size + STATIC_FMT_BUF_SIZE,
3654 GFP_KERNEL);
3655 if (tmp) {
3656 iter->fmt_size += STATIC_FMT_BUF_SIZE;
3657 iter->fmt = tmp;
3658 }
3659
3660 return tmp;
3661}
3662
3663/* Returns true if the string is safe to dereference from an event */
3664static bool trace_safe_str(struct trace_iterator *iter, const char *str)
3665{
3666 unsigned long addr = (unsigned long)str;
3667 struct trace_event *trace_event;
3668 struct trace_event_call *event;
3669
3670 /* OK if part of the event data */
3671 if ((addr >= (unsigned long)iter->ent) &&
3672 (addr < (unsigned long)iter->ent + iter->ent_size))
3673 return true;
3674
3675 /* OK if part of the temp seq buffer */
3676 if ((addr >= (unsigned long)iter->tmp_seq.buffer) &&
3677 (addr < (unsigned long)iter->tmp_seq.buffer + PAGE_SIZE))
3678 return true;
3679
3680 /* Core rodata can not be freed */
3681 if (is_kernel_rodata(addr))
3682 return true;
3683
3684 if (trace_is_tracepoint_string(str))
3685 return true;
3686
3687 /*
3688 * Now this could be a module event, referencing core module
3689 * data, which is OK.
3690 */
3691 if (!iter->ent)
3692 return false;
3693
3694 trace_event = ftrace_find_event(iter->ent->type);
3695 if (!trace_event)
3696 return false;
3697
3698 event = container_of(trace_event, struct trace_event_call, event);
3699 if (!event->mod)
3700 return false;
3701
3702 /* Would rather have rodata, but this will suffice */
3703 if (within_module_core(addr, event->mod))
3704 return true;
3705
3706 return false;
3707}
3708
3709static const char *show_buffer(struct trace_seq *s)
3710{
3711 struct seq_buf *seq = &s->seq;
3712
3713 seq_buf_terminate(seq);
3714
3715 return seq->buffer;
3716}
3717
3718static DEFINE_STATIC_KEY_FALSE(trace_no_verify);
3719
3720static int test_can_verify_check(const char *fmt, ...)
3721{
3722 char buf[16];
3723 va_list ap;
3724 int ret;
3725
3726 /*
3727 * The verifier is dependent on vsnprintf() modifies the va_list
3728 * passed to it, where it is sent as a reference. Some architectures
3729 * (like x86_32) passes it by value, which means that vsnprintf()
3730 * does not modify the va_list passed to it, and the verifier
3731 * would then need to be able to understand all the values that
3732 * vsnprintf can use. If it is passed by value, then the verifier
3733 * is disabled.
3734 */
3735 va_start(ap, fmt);
3736 vsnprintf(buf, 16, "%d", ap);
3737 ret = va_arg(ap, int);
3738 va_end(ap);
3739
3740 return ret;
3741}
3742
3743static void test_can_verify(void)
3744{
3745 if (!test_can_verify_check("%d %d", 0, 1)) {
3746 pr_info("trace event string verifier disabled\n");
3747 static_branch_inc(&trace_no_verify);
3748 }
3749}
3750
3751/**
3752 * trace_check_vprintf - Check dereferenced strings while writing to the seq buffer
3753 * @iter: The iterator that holds the seq buffer and the event being printed
3754 * @fmt: The format used to print the event
3755 * @ap: The va_list holding the data to print from @fmt.
3756 *
3757 * This writes the data into the @iter->seq buffer using the data from
3758 * @fmt and @ap. If the format has a %s, then the source of the string
3759 * is examined to make sure it is safe to print, otherwise it will
3760 * warn and print "[UNSAFE MEMORY]" in place of the dereferenced string
3761 * pointer.
3762 */
3763void trace_check_vprintf(struct trace_iterator *iter, const char *fmt,
3764 va_list ap)
3765{
3766 const char *p = fmt;
3767 const char *str;
3768 int i, j;
3769
3770 if (WARN_ON_ONCE(!fmt))
3771 return;
3772
3773 if (static_branch_unlikely(&trace_no_verify))
3774 goto print;
3775
3776 /* Don't bother checking when doing a ftrace_dump() */
3777 if (iter->fmt == static_fmt_buf)
3778 goto print;
3779
3780 while (*p) {
3781 bool star = false;
3782 int len = 0;
3783
3784 j = 0;
3785
3786 /* We only care about %s and variants */
3787 for (i = 0; p[i]; i++) {
3788 if (i + 1 >= iter->fmt_size) {
3789 /*
3790 * If we can't expand the copy buffer,
3791 * just print it.
3792 */
3793 if (!trace_iter_expand_format(iter))
3794 goto print;
3795 }
3796
3797 if (p[i] == '\\' && p[i+1]) {
3798 i++;
3799 continue;
3800 }
3801 if (p[i] == '%') {
3802 /* Need to test cases like %08.*s */
3803 for (j = 1; p[i+j]; j++) {
3804 if (isdigit(p[i+j]) ||
3805 p[i+j] == '.')
3806 continue;
3807 if (p[i+j] == '*') {
3808 star = true;
3809 continue;
3810 }
3811 break;
3812 }
3813 if (p[i+j] == 's')
3814 break;
3815 star = false;
3816 }
3817 j = 0;
3818 }
3819 /* If no %s found then just print normally */
3820 if (!p[i])
3821 break;
3822
3823 /* Copy up to the %s, and print that */
3824 strncpy(iter->fmt, p, i);
3825 iter->fmt[i] = '\0';
3826 trace_seq_vprintf(&iter->seq, iter->fmt, ap);
3827
3828 if (star)
3829 len = va_arg(ap, int);
3830
3831 /* The ap now points to the string data of the %s */
3832 str = va_arg(ap, const char *);
3833
3834 /*
3835 * If you hit this warning, it is likely that the
3836 * trace event in question used %s on a string that
3837 * was saved at the time of the event, but may not be
3838 * around when the trace is read. Use __string(),
3839 * __assign_str() and __get_str() helpers in the TRACE_EVENT()
3840 * instead. See samples/trace_events/trace-events-sample.h
3841 * for reference.
3842 */
3843 if (WARN_ONCE(!trace_safe_str(iter, str),
3844 "fmt: '%s' current_buffer: '%s'",
3845 fmt, show_buffer(&iter->seq))) {
3846 int ret;
3847
3848 /* Try to safely read the string */
3849 if (star) {
3850 if (len + 1 > iter->fmt_size)
3851 len = iter->fmt_size - 1;
3852 if (len < 0)
3853 len = 0;
3854 ret = copy_from_kernel_nofault(iter->fmt, str, len);
3855 iter->fmt[len] = 0;
3856 star = false;
3857 } else {
3858 ret = strncpy_from_kernel_nofault(iter->fmt, str,
3859 iter->fmt_size);
3860 }
3861 if (ret < 0)
3862 trace_seq_printf(&iter->seq, "(0x%px)", str);
3863 else
3864 trace_seq_printf(&iter->seq, "(0x%px:%s)",
3865 str, iter->fmt);
3866 str = "[UNSAFE-MEMORY]";
3867 strcpy(iter->fmt, "%s");
3868 } else {
3869 strncpy(iter->fmt, p + i, j + 1);
3870 iter->fmt[j+1] = '\0';
3871 }
3872 if (star)
3873 trace_seq_printf(&iter->seq, iter->fmt, len, str);
3874 else
3875 trace_seq_printf(&iter->seq, iter->fmt, str);
3876
3877 p += i + j + 1;
3878 }
3879 print:
3880 if (*p)
3881 trace_seq_vprintf(&iter->seq, p, ap);
3882}
3883
3884const char *trace_event_format(struct trace_iterator *iter, const char *fmt)
3885{
3886 const char *p, *new_fmt;
3887 char *q;
3888
3889 if (WARN_ON_ONCE(!fmt))
3890 return fmt;
3891
3892 if (!iter->tr || iter->tr->trace_flags & TRACE_ITER_HASH_PTR)
3893 return fmt;
3894
3895 p = fmt;
3896 new_fmt = q = iter->fmt;
3897 while (*p) {
3898 if (unlikely(q - new_fmt + 3 > iter->fmt_size)) {
3899 if (!trace_iter_expand_format(iter))
3900 return fmt;
3901
3902 q += iter->fmt - new_fmt;
3903 new_fmt = iter->fmt;
3904 }
3905
3906 *q++ = *p++;
3907
3908 /* Replace %p with %px */
3909 if (p[-1] == '%') {
3910 if (p[0] == '%') {
3911 *q++ = *p++;
3912 } else if (p[0] == 'p' && !isalnum(p[1])) {
3913 *q++ = *p++;
3914 *q++ = 'x';
3915 }
3916 }
3917 }
3918 *q = '\0';
3919
3920 return new_fmt;
3921}
3922
3923#define STATIC_TEMP_BUF_SIZE 128
3924static char static_temp_buf[STATIC_TEMP_BUF_SIZE] __aligned(4);
3925
3926/* Find the next real entry, without updating the iterator itself */
3927struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
3928 int *ent_cpu, u64 *ent_ts)
3929{
3930 /* __find_next_entry will reset ent_size */
3931 int ent_size = iter->ent_size;
3932 struct trace_entry *entry;
3933
3934 /*
3935 * If called from ftrace_dump(), then the iter->temp buffer
3936 * will be the static_temp_buf and not created from kmalloc.
3937 * If the entry size is greater than the buffer, we can
3938 * not save it. Just return NULL in that case. This is only
3939 * used to add markers when two consecutive events' time
3940 * stamps have a large delta. See trace_print_lat_context()
3941 */
3942 if (iter->temp == static_temp_buf &&
3943 STATIC_TEMP_BUF_SIZE < ent_size)
3944 return NULL;
3945
3946 /*
3947 * The __find_next_entry() may call peek_next_entry(), which may
3948 * call ring_buffer_peek() that may make the contents of iter->ent
3949 * undefined. Need to copy iter->ent now.
3950 */
3951 if (iter->ent && iter->ent != iter->temp) {
3952 if ((!iter->temp || iter->temp_size < iter->ent_size) &&
3953 !WARN_ON_ONCE(iter->temp == static_temp_buf)) {
3954 void *temp;
3955 temp = kmalloc(iter->ent_size, GFP_KERNEL);
3956 if (!temp)
3957 return NULL;
3958 kfree(iter->temp);
3959 iter->temp = temp;
3960 iter->temp_size = iter->ent_size;
3961 }
3962 memcpy(iter->temp, iter->ent, iter->ent_size);
3963 iter->ent = iter->temp;
3964 }
3965 entry = __find_next_entry(iter, ent_cpu, NULL, ent_ts);
3966 /* Put back the original ent_size */
3967 iter->ent_size = ent_size;
3968
3969 return entry;
3970}
3971
3972/* Find the next real entry, and increment the iterator to the next entry */
3973void *trace_find_next_entry_inc(struct trace_iterator *iter)
3974{
3975 iter->ent = __find_next_entry(iter, &iter->cpu,
3976 &iter->lost_events, &iter->ts);
3977
3978 if (iter->ent)
3979 trace_iterator_increment(iter);
3980
3981 return iter->ent ? iter : NULL;
3982}
3983
3984static void trace_consume(struct trace_iterator *iter)
3985{
3986 ring_buffer_consume(iter->array_buffer->buffer, iter->cpu, &iter->ts,
3987 &iter->lost_events);
3988}
3989
3990static void *s_next(struct seq_file *m, void *v, loff_t *pos)
3991{
3992 struct trace_iterator *iter = m->private;
3993 int i = (int)*pos;
3994 void *ent;
3995
3996 WARN_ON_ONCE(iter->leftover);
3997
3998 (*pos)++;
3999
4000 /* can't go backwards */
4001 if (iter->idx > i)
4002 return NULL;
4003
4004 if (iter->idx < 0)
4005 ent = trace_find_next_entry_inc(iter);
4006 else
4007 ent = iter;
4008
4009 while (ent && iter->idx < i)
4010 ent = trace_find_next_entry_inc(iter);
4011
4012 iter->pos = *pos;
4013
4014 return ent;
4015}
4016
4017void tracing_iter_reset(struct trace_iterator *iter, int cpu)
4018{
4019 struct ring_buffer_iter *buf_iter;
4020 unsigned long entries = 0;
4021 u64 ts;
4022
4023 per_cpu_ptr(iter->array_buffer->data, cpu)->skipped_entries = 0;
4024
4025 buf_iter = trace_buffer_iter(iter, cpu);
4026 if (!buf_iter)
4027 return;
4028
4029 ring_buffer_iter_reset(buf_iter);
4030
4031 /*
4032 * We could have the case with the max latency tracers
4033 * that a reset never took place on a cpu. This is evident
4034 * by the timestamp being before the start of the buffer.
4035 */
4036 while (ring_buffer_iter_peek(buf_iter, &ts)) {
4037 if (ts >= iter->array_buffer->time_start)
4038 break;
4039 entries++;
4040 ring_buffer_iter_advance(buf_iter);
4041 }
4042
4043 per_cpu_ptr(iter->array_buffer->data, cpu)->skipped_entries = entries;
4044}
4045
4046/*
4047 * The current tracer is copied to avoid a global locking
4048 * all around.
4049 */
4050static void *s_start(struct seq_file *m, loff_t *pos)
4051{
4052 struct trace_iterator *iter = m->private;
4053 struct trace_array *tr = iter->tr;
4054 int cpu_file = iter->cpu_file;
4055 void *p = NULL;
4056 loff_t l = 0;
4057 int cpu;
4058
4059 /*
4060 * copy the tracer to avoid using a global lock all around.
4061 * iter->trace is a copy of current_trace, the pointer to the
4062 * name may be used instead of a strcmp(), as iter->trace->name
4063 * will point to the same string as current_trace->name.
4064 */
4065 mutex_lock(&trace_types_lock);
4066 if (unlikely(tr->current_trace && iter->trace->name != tr->current_trace->name))
4067 *iter->trace = *tr->current_trace;
4068 mutex_unlock(&trace_types_lock);
4069
4070#ifdef CONFIG_TRACER_MAX_TRACE
4071 if (iter->snapshot && iter->trace->use_max_tr)
4072 return ERR_PTR(-EBUSY);
4073#endif
4074
4075 if (*pos != iter->pos) {
4076 iter->ent = NULL;
4077 iter->cpu = 0;
4078 iter->idx = -1;
4079
4080 if (cpu_file == RING_BUFFER_ALL_CPUS) {
4081 for_each_tracing_cpu(cpu)
4082 tracing_iter_reset(iter, cpu);
4083 } else
4084 tracing_iter_reset(iter, cpu_file);
4085
4086 iter->leftover = 0;
4087 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
4088 ;
4089
4090 } else {
4091 /*
4092 * If we overflowed the seq_file before, then we want
4093 * to just reuse the trace_seq buffer again.
4094 */
4095 if (iter->leftover)
4096 p = iter;
4097 else {
4098 l = *pos - 1;
4099 p = s_next(m, p, &l);
4100 }
4101 }
4102
4103 trace_event_read_lock();
4104 trace_access_lock(cpu_file);
4105 return p;
4106}
4107
4108static void s_stop(struct seq_file *m, void *p)
4109{
4110 struct trace_iterator *iter = m->private;
4111
4112#ifdef CONFIG_TRACER_MAX_TRACE
4113 if (iter->snapshot && iter->trace->use_max_tr)
4114 return;
4115#endif
4116
4117 trace_access_unlock(iter->cpu_file);
4118 trace_event_read_unlock();
4119}
4120
4121static void
4122get_total_entries_cpu(struct array_buffer *buf, unsigned long *total,
4123 unsigned long *entries, int cpu)
4124{
4125 unsigned long count;
4126
4127 count = ring_buffer_entries_cpu(buf->buffer, cpu);
4128 /*
4129 * If this buffer has skipped entries, then we hold all
4130 * entries for the trace and we need to ignore the
4131 * ones before the time stamp.
4132 */
4133 if (per_cpu_ptr(buf->data, cpu)->skipped_entries) {
4134 count -= per_cpu_ptr(buf->data, cpu)->skipped_entries;
4135 /* total is the same as the entries */
4136 *total = count;
4137 } else
4138 *total = count +
4139 ring_buffer_overrun_cpu(buf->buffer, cpu);
4140 *entries = count;
4141}
4142
4143static void
4144get_total_entries(struct array_buffer *buf,
4145 unsigned long *total, unsigned long *entries)
4146{
4147 unsigned long t, e;
4148 int cpu;
4149
4150 *total = 0;
4151 *entries = 0;
4152
4153 for_each_tracing_cpu(cpu) {
4154 get_total_entries_cpu(buf, &t, &e, cpu);
4155 *total += t;
4156 *entries += e;
4157 }
4158}
4159
4160unsigned long trace_total_entries_cpu(struct trace_array *tr, int cpu)
4161{
4162 unsigned long total, entries;
4163
4164 if (!tr)
4165 tr = &global_trace;
4166
4167 get_total_entries_cpu(&tr->array_buffer, &total, &entries, cpu);
4168
4169 return entries;
4170}
4171
4172unsigned long trace_total_entries(struct trace_array *tr)
4173{
4174 unsigned long total, entries;
4175
4176 if (!tr)
4177 tr = &global_trace;
4178
4179 get_total_entries(&tr->array_buffer, &total, &entries);
4180
4181 return entries;
4182}
4183
4184static void print_lat_help_header(struct seq_file *m)
4185{
4186 seq_puts(m, "# _------=> CPU# \n"
4187 "# / _-----=> irqs-off \n"
4188 "# | / _----=> need-resched \n"
4189 "# || / _---=> hardirq/softirq \n"
4190 "# ||| / _--=> preempt-depth \n"
4191 "# |||| / delay \n"
4192 "# cmd pid ||||| time | caller \n"
4193 "# \\ / ||||| \\ | / \n");
4194}
4195
4196static void print_event_info(struct array_buffer *buf, struct seq_file *m)
4197{
4198 unsigned long total;
4199 unsigned long entries;
4200
4201 get_total_entries(buf, &total, &entries);
4202 seq_printf(m, "# entries-in-buffer/entries-written: %lu/%lu #P:%d\n",
4203 entries, total, num_online_cpus());
4204 seq_puts(m, "#\n");
4205}
4206
4207static void print_func_help_header(struct array_buffer *buf, struct seq_file *m,
4208 unsigned int flags)
4209{
4210 bool tgid = flags & TRACE_ITER_RECORD_TGID;
4211
4212 print_event_info(buf, m);
4213
4214 seq_printf(m, "# TASK-PID %s CPU# TIMESTAMP FUNCTION\n", tgid ? " TGID " : "");
4215 seq_printf(m, "# | | %s | | |\n", tgid ? " | " : "");
4216}
4217
4218static void print_func_help_header_irq(struct array_buffer *buf, struct seq_file *m,
4219 unsigned int flags)
4220{
4221 bool tgid = flags & TRACE_ITER_RECORD_TGID;
4222 const char *space = " ";
4223 int prec = tgid ? 12 : 2;
4224
4225 print_event_info(buf, m);
4226
4227 seq_printf(m, "# %.*s _-----=> irqs-off\n", prec, space);
4228 seq_printf(m, "# %.*s / _----=> need-resched\n", prec, space);
4229 seq_printf(m, "# %.*s| / _---=> hardirq/softirq\n", prec, space);
4230 seq_printf(m, "# %.*s|| / _--=> preempt-depth\n", prec, space);
4231 seq_printf(m, "# %.*s||| / delay\n", prec, space);
4232 seq_printf(m, "# TASK-PID %.*s CPU# |||| TIMESTAMP FUNCTION\n", prec, " TGID ");
4233 seq_printf(m, "# | | %.*s | |||| | |\n", prec, " | ");
4234}
4235
4236void
4237print_trace_header(struct seq_file *m, struct trace_iterator *iter)
4238{
4239 unsigned long sym_flags = (global_trace.trace_flags & TRACE_ITER_SYM_MASK);
4240 struct array_buffer *buf = iter->array_buffer;
4241 struct trace_array_cpu *data = per_cpu_ptr(buf->data, buf->cpu);
4242 struct tracer *type = iter->trace;
4243 unsigned long entries;
4244 unsigned long total;
4245 const char *name = "preemption";
4246
4247 name = type->name;
4248
4249 get_total_entries(buf, &total, &entries);
4250
4251 seq_printf(m, "# %s latency trace v1.1.5 on %s\n",
4252 name, UTS_RELEASE);
4253 seq_puts(m, "# -----------------------------------"
4254 "---------------------------------\n");
4255 seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d |"
4256 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
4257 nsecs_to_usecs(data->saved_latency),
4258 entries,
4259 total,
4260 buf->cpu,
4261#if defined(CONFIG_PREEMPT_NONE)
4262 "server",
4263#elif defined(CONFIG_PREEMPT_VOLUNTARY)
4264 "desktop",
4265#elif defined(CONFIG_PREEMPT)
4266 "preempt",
4267#elif defined(CONFIG_PREEMPT_RT)
4268 "preempt_rt",
4269#else
4270 "unknown",
4271#endif
4272 /* These are reserved for later use */
4273 0, 0, 0, 0);
4274#ifdef CONFIG_SMP
4275 seq_printf(m, " #P:%d)\n", num_online_cpus());
4276#else
4277 seq_puts(m, ")\n");
4278#endif
4279 seq_puts(m, "# -----------------\n");
4280 seq_printf(m, "# | task: %.16s-%d "
4281 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
4282 data->comm, data->pid,
4283 from_kuid_munged(seq_user_ns(m), data->uid), data->nice,
4284 data->policy, data->rt_priority);
4285 seq_puts(m, "# -----------------\n");
4286
4287 if (data->critical_start) {
4288 seq_puts(m, "# => started at: ");
4289 seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
4290 trace_print_seq(m, &iter->seq);
4291 seq_puts(m, "\n# => ended at: ");
4292 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
4293 trace_print_seq(m, &iter->seq);
4294 seq_puts(m, "\n#\n");
4295 }
4296
4297 seq_puts(m, "#\n");
4298}
4299
4300static void test_cpu_buff_start(struct trace_iterator *iter)
4301{
4302 struct trace_seq *s = &iter->seq;
4303 struct trace_array *tr = iter->tr;
4304
4305 if (!(tr->trace_flags & TRACE_ITER_ANNOTATE))
4306 return;
4307
4308 if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
4309 return;
4310
4311 if (cpumask_available(iter->started) &&
4312 cpumask_test_cpu(iter->cpu, iter->started))
4313 return;
4314
4315 if (per_cpu_ptr(iter->array_buffer->data, iter->cpu)->skipped_entries)
4316 return;
4317
4318 if (cpumask_available(iter->started))
4319 cpumask_set_cpu(iter->cpu, iter->started);
4320
4321 /* Don't print started cpu buffer for the first entry of the trace */
4322 if (iter->idx > 1)
4323 trace_seq_printf(s, "##### CPU %u buffer started ####\n",
4324 iter->cpu);
4325}
4326
4327static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
4328{
4329 struct trace_array *tr = iter->tr;
4330 struct trace_seq *s = &iter->seq;
4331 unsigned long sym_flags = (tr->trace_flags & TRACE_ITER_SYM_MASK);
4332 struct trace_entry *entry;
4333 struct trace_event *event;
4334
4335 entry = iter->ent;
4336
4337 test_cpu_buff_start(iter);
4338
4339 event = ftrace_find_event(entry->type);
4340
4341 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
4342 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
4343 trace_print_lat_context(iter);
4344 else
4345 trace_print_context(iter);
4346 }
4347
4348 if (trace_seq_has_overflowed(s))
4349 return TRACE_TYPE_PARTIAL_LINE;
4350
4351 if (event)
4352 return event->funcs->trace(iter, sym_flags, event);
4353
4354 trace_seq_printf(s, "Unknown type %d\n", entry->type);
4355
4356 return trace_handle_return(s);
4357}
4358
4359static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
4360{
4361 struct trace_array *tr = iter->tr;
4362 struct trace_seq *s = &iter->seq;
4363 struct trace_entry *entry;
4364 struct trace_event *event;
4365
4366 entry = iter->ent;
4367
4368 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO)
4369 trace_seq_printf(s, "%d %d %llu ",
4370 entry->pid, iter->cpu, iter->ts);
4371
4372 if (trace_seq_has_overflowed(s))
4373 return TRACE_TYPE_PARTIAL_LINE;
4374
4375 event = ftrace_find_event(entry->type);
4376 if (event)
4377 return event->funcs->raw(iter, 0, event);
4378
4379 trace_seq_printf(s, "%d ?\n", entry->type);
4380
4381 return trace_handle_return(s);
4382}
4383
4384static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
4385{
4386 struct trace_array *tr = iter->tr;
4387 struct trace_seq *s = &iter->seq;
4388 unsigned char newline = '\n';
4389 struct trace_entry *entry;
4390 struct trace_event *event;
4391
4392 entry = iter->ent;
4393
4394 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
4395 SEQ_PUT_HEX_FIELD(s, entry->pid);
4396 SEQ_PUT_HEX_FIELD(s, iter->cpu);
4397 SEQ_PUT_HEX_FIELD(s, iter->ts);
4398 if (trace_seq_has_overflowed(s))
4399 return TRACE_TYPE_PARTIAL_LINE;
4400 }
4401
4402 event = ftrace_find_event(entry->type);
4403 if (event) {
4404 enum print_line_t ret = event->funcs->hex(iter, 0, event);
4405 if (ret != TRACE_TYPE_HANDLED)
4406 return ret;
4407 }
4408
4409 SEQ_PUT_FIELD(s, newline);
4410
4411 return trace_handle_return(s);
4412}
4413
4414static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
4415{
4416 struct trace_array *tr = iter->tr;
4417 struct trace_seq *s = &iter->seq;
4418 struct trace_entry *entry;
4419 struct trace_event *event;
4420
4421 entry = iter->ent;
4422
4423 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
4424 SEQ_PUT_FIELD(s, entry->pid);
4425 SEQ_PUT_FIELD(s, iter->cpu);
4426 SEQ_PUT_FIELD(s, iter->ts);
4427 if (trace_seq_has_overflowed(s))
4428 return TRACE_TYPE_PARTIAL_LINE;
4429 }
4430
4431 event = ftrace_find_event(entry->type);
4432 return event ? event->funcs->binary(iter, 0, event) :
4433 TRACE_TYPE_HANDLED;
4434}
4435
4436int trace_empty(struct trace_iterator *iter)
4437{
4438 struct ring_buffer_iter *buf_iter;
4439 int cpu;
4440
4441 /* If we are looking at one CPU buffer, only check that one */
4442 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
4443 cpu = iter->cpu_file;
4444 buf_iter = trace_buffer_iter(iter, cpu);
4445 if (buf_iter) {
4446 if (!ring_buffer_iter_empty(buf_iter))
4447 return 0;
4448 } else {
4449 if (!ring_buffer_empty_cpu(iter->array_buffer->buffer, cpu))
4450 return 0;
4451 }
4452 return 1;
4453 }
4454
4455 for_each_tracing_cpu(cpu) {
4456 buf_iter = trace_buffer_iter(iter, cpu);
4457 if (buf_iter) {
4458 if (!ring_buffer_iter_empty(buf_iter))
4459 return 0;
4460 } else {
4461 if (!ring_buffer_empty_cpu(iter->array_buffer->buffer, cpu))
4462 return 0;
4463 }
4464 }
4465
4466 return 1;
4467}
4468
4469/* Called with trace_event_read_lock() held. */
4470enum print_line_t print_trace_line(struct trace_iterator *iter)
4471{
4472 struct trace_array *tr = iter->tr;
4473 unsigned long trace_flags = tr->trace_flags;
4474 enum print_line_t ret;
4475
4476 if (iter->lost_events) {
4477 if (iter->lost_events == (unsigned long)-1)
4478 trace_seq_printf(&iter->seq, "CPU:%d [LOST EVENTS]\n",
4479 iter->cpu);
4480 else
4481 trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
4482 iter->cpu, iter->lost_events);
4483 if (trace_seq_has_overflowed(&iter->seq))
4484 return TRACE_TYPE_PARTIAL_LINE;
4485 }
4486
4487 if (iter->trace && iter->trace->print_line) {
4488 ret = iter->trace->print_line(iter);
4489 if (ret != TRACE_TYPE_UNHANDLED)
4490 return ret;
4491 }
4492
4493 if (iter->ent->type == TRACE_BPUTS &&
4494 trace_flags & TRACE_ITER_PRINTK &&
4495 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
4496 return trace_print_bputs_msg_only(iter);
4497
4498 if (iter->ent->type == TRACE_BPRINT &&
4499 trace_flags & TRACE_ITER_PRINTK &&
4500 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
4501 return trace_print_bprintk_msg_only(iter);
4502
4503 if (iter->ent->type == TRACE_PRINT &&
4504 trace_flags & TRACE_ITER_PRINTK &&
4505 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
4506 return trace_print_printk_msg_only(iter);
4507
4508 if (trace_flags & TRACE_ITER_BIN)
4509 return print_bin_fmt(iter);
4510
4511 if (trace_flags & TRACE_ITER_HEX)
4512 return print_hex_fmt(iter);
4513
4514 if (trace_flags & TRACE_ITER_RAW)
4515 return print_raw_fmt(iter);
4516
4517 return print_trace_fmt(iter);
4518}
4519
4520void trace_latency_header(struct seq_file *m)
4521{
4522 struct trace_iterator *iter = m->private;
4523 struct trace_array *tr = iter->tr;
4524
4525 /* print nothing if the buffers are empty */
4526 if (trace_empty(iter))
4527 return;
4528
4529 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
4530 print_trace_header(m, iter);
4531
4532 if (!(tr->trace_flags & TRACE_ITER_VERBOSE))
4533 print_lat_help_header(m);
4534}
4535
4536void trace_default_header(struct seq_file *m)
4537{
4538 struct trace_iterator *iter = m->private;
4539 struct trace_array *tr = iter->tr;
4540 unsigned long trace_flags = tr->trace_flags;
4541
4542 if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
4543 return;
4544
4545 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
4546 /* print nothing if the buffers are empty */
4547 if (trace_empty(iter))
4548 return;
4549 print_trace_header(m, iter);
4550 if (!(trace_flags & TRACE_ITER_VERBOSE))
4551 print_lat_help_header(m);
4552 } else {
4553 if (!(trace_flags & TRACE_ITER_VERBOSE)) {
4554 if (trace_flags & TRACE_ITER_IRQ_INFO)
4555 print_func_help_header_irq(iter->array_buffer,
4556 m, trace_flags);
4557 else
4558 print_func_help_header(iter->array_buffer, m,
4559 trace_flags);
4560 }
4561 }
4562}
4563
4564static void test_ftrace_alive(struct seq_file *m)
4565{
4566 if (!ftrace_is_dead())
4567 return;
4568 seq_puts(m, "# WARNING: FUNCTION TRACING IS CORRUPTED\n"
4569 "# MAY BE MISSING FUNCTION EVENTS\n");
4570}
4571
4572#ifdef CONFIG_TRACER_MAX_TRACE
4573static void show_snapshot_main_help(struct seq_file *m)
4574{
4575 seq_puts(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n"
4576 "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
4577 "# Takes a snapshot of the main buffer.\n"
4578 "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate or free)\n"
4579 "# (Doesn't have to be '2' works with any number that\n"
4580 "# is not a '0' or '1')\n");
4581}
4582
4583static void show_snapshot_percpu_help(struct seq_file *m)
4584{
4585 seq_puts(m, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n");
4586#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
4587 seq_puts(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
4588 "# Takes a snapshot of the main buffer for this cpu.\n");
4589#else
4590 seq_puts(m, "# echo 1 > snapshot : Not supported with this kernel.\n"
4591 "# Must use main snapshot file to allocate.\n");
4592#endif
4593 seq_puts(m, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n"
4594 "# (Doesn't have to be '2' works with any number that\n"
4595 "# is not a '0' or '1')\n");
4596}
4597
4598static void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter)
4599{
4600 if (iter->tr->allocated_snapshot)
4601 seq_puts(m, "#\n# * Snapshot is allocated *\n#\n");
4602 else
4603 seq_puts(m, "#\n# * Snapshot is freed *\n#\n");
4604
4605 seq_puts(m, "# Snapshot commands:\n");
4606 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
4607 show_snapshot_main_help(m);
4608 else
4609 show_snapshot_percpu_help(m);
4610}
4611#else
4612/* Should never be called */
4613static inline void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter) { }
4614#endif
4615
4616static int s_show(struct seq_file *m, void *v)
4617{
4618 struct trace_iterator *iter = v;
4619 int ret;
4620
4621 if (iter->ent == NULL) {
4622 if (iter->tr) {
4623 seq_printf(m, "# tracer: %s\n", iter->trace->name);
4624 seq_puts(m, "#\n");
4625 test_ftrace_alive(m);
4626 }
4627 if (iter->snapshot && trace_empty(iter))
4628 print_snapshot_help(m, iter);
4629 else if (iter->trace && iter->trace->print_header)
4630 iter->trace->print_header(m);
4631 else
4632 trace_default_header(m);
4633
4634 } else if (iter->leftover) {
4635 /*
4636 * If we filled the seq_file buffer earlier, we
4637 * want to just show it now.
4638 */
4639 ret = trace_print_seq(m, &iter->seq);
4640
4641 /* ret should this time be zero, but you never know */
4642 iter->leftover = ret;
4643
4644 } else {
4645 print_trace_line(iter);
4646 ret = trace_print_seq(m, &iter->seq);
4647 /*
4648 * If we overflow the seq_file buffer, then it will
4649 * ask us for this data again at start up.
4650 * Use that instead.
4651 * ret is 0 if seq_file write succeeded.
4652 * -1 otherwise.
4653 */
4654 iter->leftover = ret;
4655 }
4656
4657 return 0;
4658}
4659
4660/*
4661 * Should be used after trace_array_get(), trace_types_lock
4662 * ensures that i_cdev was already initialized.
4663 */
4664static inline int tracing_get_cpu(struct inode *inode)
4665{
4666 if (inode->i_cdev) /* See trace_create_cpu_file() */
4667 return (long)inode->i_cdev - 1;
4668 return RING_BUFFER_ALL_CPUS;
4669}
4670
4671static const struct seq_operations tracer_seq_ops = {
4672 .start = s_start,
4673 .next = s_next,
4674 .stop = s_stop,
4675 .show = s_show,
4676};
4677
4678static struct trace_iterator *
4679__tracing_open(struct inode *inode, struct file *file, bool snapshot)
4680{
4681 struct trace_array *tr = inode->i_private;
4682 struct trace_iterator *iter;
4683 int cpu;
4684
4685 if (tracing_disabled)
4686 return ERR_PTR(-ENODEV);
4687
4688 iter = __seq_open_private(file, &tracer_seq_ops, sizeof(*iter));
4689 if (!iter)
4690 return ERR_PTR(-ENOMEM);
4691
4692 iter->buffer_iter = kcalloc(nr_cpu_ids, sizeof(*iter->buffer_iter),
4693 GFP_KERNEL);
4694 if (!iter->buffer_iter)
4695 goto release;
4696
4697 /*
4698 * trace_find_next_entry() may need to save off iter->ent.
4699 * It will place it into the iter->temp buffer. As most
4700 * events are less than 128, allocate a buffer of that size.
4701 * If one is greater, then trace_find_next_entry() will
4702 * allocate a new buffer to adjust for the bigger iter->ent.
4703 * It's not critical if it fails to get allocated here.
4704 */
4705 iter->temp = kmalloc(128, GFP_KERNEL);
4706 if (iter->temp)
4707 iter->temp_size = 128;
4708
4709 /*
4710 * trace_event_printf() may need to modify given format
4711 * string to replace %p with %px so that it shows real address
4712 * instead of hash value. However, that is only for the event
4713 * tracing, other tracer may not need. Defer the allocation
4714 * until it is needed.
4715 */
4716 iter->fmt = NULL;
4717 iter->fmt_size = 0;
4718
4719 /*
4720 * We make a copy of the current tracer to avoid concurrent
4721 * changes on it while we are reading.
4722 */
4723 mutex_lock(&trace_types_lock);
4724 iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL);
4725 if (!iter->trace)
4726 goto fail;
4727
4728 *iter->trace = *tr->current_trace;
4729
4730 if (!zalloc_cpumask_var(&iter->started, GFP_KERNEL))
4731 goto fail;
4732
4733 iter->tr = tr;
4734
4735#ifdef CONFIG_TRACER_MAX_TRACE
4736 /* Currently only the top directory has a snapshot */
4737 if (tr->current_trace->print_max || snapshot)
4738 iter->array_buffer = &tr->max_buffer;
4739 else
4740#endif
4741 iter->array_buffer = &tr->array_buffer;
4742 iter->snapshot = snapshot;
4743 iter->pos = -1;
4744 iter->cpu_file = tracing_get_cpu(inode);
4745 mutex_init(&iter->mutex);
4746
4747 /* Notify the tracer early; before we stop tracing. */
4748 if (iter->trace->open)
4749 iter->trace->open(iter);
4750
4751 /* Annotate start of buffers if we had overruns */
4752 if (ring_buffer_overruns(iter->array_buffer->buffer))
4753 iter->iter_flags |= TRACE_FILE_ANNOTATE;
4754
4755 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
4756 if (trace_clocks[tr->clock_id].in_ns)
4757 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
4758
4759 /*
4760 * If pause-on-trace is enabled, then stop the trace while
4761 * dumping, unless this is the "snapshot" file
4762 */
4763 if (!iter->snapshot && (tr->trace_flags & TRACE_ITER_PAUSE_ON_TRACE))
4764 tracing_stop_tr(tr);
4765
4766 if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
4767 for_each_tracing_cpu(cpu) {
4768 iter->buffer_iter[cpu] =
4769 ring_buffer_read_prepare(iter->array_buffer->buffer,
4770 cpu, GFP_KERNEL);
4771 }
4772 ring_buffer_read_prepare_sync();
4773 for_each_tracing_cpu(cpu) {
4774 ring_buffer_read_start(iter->buffer_iter[cpu]);
4775 tracing_iter_reset(iter, cpu);
4776 }
4777 } else {
4778 cpu = iter->cpu_file;
4779 iter->buffer_iter[cpu] =
4780 ring_buffer_read_prepare(iter->array_buffer->buffer,
4781 cpu, GFP_KERNEL);
4782 ring_buffer_read_prepare_sync();
4783 ring_buffer_read_start(iter->buffer_iter[cpu]);
4784 tracing_iter_reset(iter, cpu);
4785 }
4786
4787 mutex_unlock(&trace_types_lock);
4788
4789 return iter;
4790
4791 fail:
4792 mutex_unlock(&trace_types_lock);
4793 kfree(iter->trace);
4794 kfree(iter->temp);
4795 kfree(iter->buffer_iter);
4796release:
4797 seq_release_private(inode, file);
4798 return ERR_PTR(-ENOMEM);
4799}
4800
4801int tracing_open_generic(struct inode *inode, struct file *filp)
4802{
4803 int ret;
4804
4805 ret = tracing_check_open_get_tr(NULL);
4806 if (ret)
4807 return ret;
4808
4809 filp->private_data = inode->i_private;
4810 return 0;
4811}
4812
4813bool tracing_is_disabled(void)
4814{
4815 return (tracing_disabled) ? true: false;
4816}
4817
4818/*
4819 * Open and update trace_array ref count.
4820 * Must have the current trace_array passed to it.
4821 */
4822int tracing_open_generic_tr(struct inode *inode, struct file *filp)
4823{
4824 struct trace_array *tr = inode->i_private;
4825 int ret;
4826
4827 ret = tracing_check_open_get_tr(tr);
4828 if (ret)
4829 return ret;
4830
4831 filp->private_data = inode->i_private;
4832
4833 return 0;
4834}
4835
4836static int tracing_release(struct inode *inode, struct file *file)
4837{
4838 struct trace_array *tr = inode->i_private;
4839 struct seq_file *m = file->private_data;
4840 struct trace_iterator *iter;
4841 int cpu;
4842
4843 if (!(file->f_mode & FMODE_READ)) {
4844 trace_array_put(tr);
4845 return 0;
4846 }
4847
4848 /* Writes do not use seq_file */
4849 iter = m->private;
4850 mutex_lock(&trace_types_lock);
4851
4852 for_each_tracing_cpu(cpu) {
4853 if (iter->buffer_iter[cpu])
4854 ring_buffer_read_finish(iter->buffer_iter[cpu]);
4855 }
4856
4857 if (iter->trace && iter->trace->close)
4858 iter->trace->close(iter);
4859
4860 if (!iter->snapshot && tr->stop_count)
4861 /* reenable tracing if it was previously enabled */
4862 tracing_start_tr(tr);
4863
4864 __trace_array_put(tr);
4865
4866 mutex_unlock(&trace_types_lock);
4867
4868 mutex_destroy(&iter->mutex);
4869 free_cpumask_var(iter->started);
4870 kfree(iter->fmt);
4871 kfree(iter->temp);
4872 kfree(iter->trace);
4873 kfree(iter->buffer_iter);
4874 seq_release_private(inode, file);
4875
4876 return 0;
4877}
4878
4879static int tracing_release_generic_tr(struct inode *inode, struct file *file)
4880{
4881 struct trace_array *tr = inode->i_private;
4882
4883 trace_array_put(tr);
4884 return 0;
4885}
4886
4887static int tracing_single_release_tr(struct inode *inode, struct file *file)
4888{
4889 struct trace_array *tr = inode->i_private;
4890
4891 trace_array_put(tr);
4892
4893 return single_release(inode, file);
4894}
4895
4896static int tracing_open(struct inode *inode, struct file *file)
4897{
4898 struct trace_array *tr = inode->i_private;
4899 struct trace_iterator *iter;
4900 int ret;
4901
4902 ret = tracing_check_open_get_tr(tr);
4903 if (ret)
4904 return ret;
4905
4906 /* If this file was open for write, then erase contents */
4907 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
4908 int cpu = tracing_get_cpu(inode);
4909 struct array_buffer *trace_buf = &tr->array_buffer;
4910
4911#ifdef CONFIG_TRACER_MAX_TRACE
4912 if (tr->current_trace->print_max)
4913 trace_buf = &tr->max_buffer;
4914#endif
4915
4916 if (cpu == RING_BUFFER_ALL_CPUS)
4917 tracing_reset_online_cpus(trace_buf);
4918 else
4919 tracing_reset_cpu(trace_buf, cpu);
4920 }
4921
4922 if (file->f_mode & FMODE_READ) {
4923 iter = __tracing_open(inode, file, false);
4924 if (IS_ERR(iter))
4925 ret = PTR_ERR(iter);
4926 else if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
4927 iter->iter_flags |= TRACE_FILE_LAT_FMT;
4928 }
4929
4930 if (ret < 0)
4931 trace_array_put(tr);
4932
4933 return ret;
4934}
4935
4936/*
4937 * Some tracers are not suitable for instance buffers.
4938 * A tracer is always available for the global array (toplevel)
4939 * or if it explicitly states that it is.
4940 */
4941static bool
4942trace_ok_for_array(struct tracer *t, struct trace_array *tr)
4943{
4944 return (tr->flags & TRACE_ARRAY_FL_GLOBAL) || t->allow_instances;
4945}
4946
4947/* Find the next tracer that this trace array may use */
4948static struct tracer *
4949get_tracer_for_array(struct trace_array *tr, struct tracer *t)
4950{
4951 while (t && !trace_ok_for_array(t, tr))
4952 t = t->next;
4953
4954 return t;
4955}
4956
4957static void *
4958t_next(struct seq_file *m, void *v, loff_t *pos)
4959{
4960 struct trace_array *tr = m->private;
4961 struct tracer *t = v;
4962
4963 (*pos)++;
4964
4965 if (t)
4966 t = get_tracer_for_array(tr, t->next);
4967
4968 return t;
4969}
4970
4971static void *t_start(struct seq_file *m, loff_t *pos)
4972{
4973 struct trace_array *tr = m->private;
4974 struct tracer *t;
4975 loff_t l = 0;
4976
4977 mutex_lock(&trace_types_lock);
4978
4979 t = get_tracer_for_array(tr, trace_types);
4980 for (; t && l < *pos; t = t_next(m, t, &l))
4981 ;
4982
4983 return t;
4984}
4985
4986static void t_stop(struct seq_file *m, void *p)
4987{
4988 mutex_unlock(&trace_types_lock);
4989}
4990
4991static int t_show(struct seq_file *m, void *v)
4992{
4993 struct tracer *t = v;
4994
4995 if (!t)
4996 return 0;
4997
4998 seq_puts(m, t->name);
4999 if (t->next)
5000 seq_putc(m, ' ');
5001 else
5002 seq_putc(m, '\n');
5003
5004 return 0;
5005}
5006
5007static const struct seq_operations show_traces_seq_ops = {
5008 .start = t_start,
5009 .next = t_next,
5010 .stop = t_stop,
5011 .show = t_show,
5012};
5013
5014static int show_traces_open(struct inode *inode, struct file *file)
5015{
5016 struct trace_array *tr = inode->i_private;
5017 struct seq_file *m;
5018 int ret;
5019
5020 ret = tracing_check_open_get_tr(tr);
5021 if (ret)
5022 return ret;
5023
5024 ret = seq_open(file, &show_traces_seq_ops);
5025 if (ret) {
5026 trace_array_put(tr);
5027 return ret;
5028 }
5029
5030 m = file->private_data;
5031 m->private = tr;
5032
5033 return 0;
5034}
5035
5036static int show_traces_release(struct inode *inode, struct file *file)
5037{
5038 struct trace_array *tr = inode->i_private;
5039
5040 trace_array_put(tr);
5041 return seq_release(inode, file);
5042}
5043
5044static ssize_t
5045tracing_write_stub(struct file *filp, const char __user *ubuf,
5046 size_t count, loff_t *ppos)
5047{
5048 return count;
5049}
5050
5051loff_t tracing_lseek(struct file *file, loff_t offset, int whence)
5052{
5053 int ret;
5054
5055 if (file->f_mode & FMODE_READ)
5056 ret = seq_lseek(file, offset, whence);
5057 else
5058 file->f_pos = ret = 0;
5059
5060 return ret;
5061}
5062
5063static const struct file_operations tracing_fops = {
5064 .open = tracing_open,
5065 .read = seq_read,
5066 .write = tracing_write_stub,
5067 .llseek = tracing_lseek,
5068 .release = tracing_release,
5069};
5070
5071static const struct file_operations show_traces_fops = {
5072 .open = show_traces_open,
5073 .read = seq_read,
5074 .llseek = seq_lseek,
5075 .release = show_traces_release,
5076};
5077
5078static ssize_t
5079tracing_cpumask_read(struct file *filp, char __user *ubuf,
5080 size_t count, loff_t *ppos)
5081{
5082 struct trace_array *tr = file_inode(filp)->i_private;
5083 char *mask_str;
5084 int len;
5085
5086 len = snprintf(NULL, 0, "%*pb\n",
5087 cpumask_pr_args(tr->tracing_cpumask)) + 1;
5088 mask_str = kmalloc(len, GFP_KERNEL);
5089 if (!mask_str)
5090 return -ENOMEM;
5091
5092 len = snprintf(mask_str, len, "%*pb\n",
5093 cpumask_pr_args(tr->tracing_cpumask));
5094 if (len >= count) {
5095 count = -EINVAL;
5096 goto out_err;
5097 }
5098 count = simple_read_from_buffer(ubuf, count, ppos, mask_str, len);
5099
5100out_err:
5101 kfree(mask_str);
5102
5103 return count;
5104}
5105
5106int tracing_set_cpumask(struct trace_array *tr,
5107 cpumask_var_t tracing_cpumask_new)
5108{
5109 int cpu;
5110
5111 if (!tr)
5112 return -EINVAL;
5113
5114 local_irq_disable();
5115 arch_spin_lock(&tr->max_lock);
5116 for_each_tracing_cpu(cpu) {
5117 /*
5118 * Increase/decrease the disabled counter if we are
5119 * about to flip a bit in the cpumask:
5120 */
5121 if (cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
5122 !cpumask_test_cpu(cpu, tracing_cpumask_new)) {
5123 atomic_inc(&per_cpu_ptr(tr->array_buffer.data, cpu)->disabled);
5124 ring_buffer_record_disable_cpu(tr->array_buffer.buffer, cpu);
5125 }
5126 if (!cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
5127 cpumask_test_cpu(cpu, tracing_cpumask_new)) {
5128 atomic_dec(&per_cpu_ptr(tr->array_buffer.data, cpu)->disabled);
5129 ring_buffer_record_enable_cpu(tr->array_buffer.buffer, cpu);
5130 }
5131 }
5132 arch_spin_unlock(&tr->max_lock);
5133 local_irq_enable();
5134
5135 cpumask_copy(tr->tracing_cpumask, tracing_cpumask_new);
5136
5137 return 0;
5138}
5139
5140static ssize_t
5141tracing_cpumask_write(struct file *filp, const char __user *ubuf,
5142 size_t count, loff_t *ppos)
5143{
5144 struct trace_array *tr = file_inode(filp)->i_private;
5145 cpumask_var_t tracing_cpumask_new;
5146 int err;
5147
5148 if (!zalloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
5149 return -ENOMEM;
5150
5151 err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
5152 if (err)
5153 goto err_free;
5154
5155 err = tracing_set_cpumask(tr, tracing_cpumask_new);
5156 if (err)
5157 goto err_free;
5158
5159 free_cpumask_var(tracing_cpumask_new);
5160
5161 return count;
5162
5163err_free:
5164 free_cpumask_var(tracing_cpumask_new);
5165
5166 return err;
5167}
5168
5169static const struct file_operations tracing_cpumask_fops = {
5170 .open = tracing_open_generic_tr,
5171 .read = tracing_cpumask_read,
5172 .write = tracing_cpumask_write,
5173 .release = tracing_release_generic_tr,
5174 .llseek = generic_file_llseek,
5175};
5176
5177static int tracing_trace_options_show(struct seq_file *m, void *v)
5178{
5179 struct tracer_opt *trace_opts;
5180 struct trace_array *tr = m->private;
5181 u32 tracer_flags;
5182 int i;
5183
5184 mutex_lock(&trace_types_lock);
5185 tracer_flags = tr->current_trace->flags->val;
5186 trace_opts = tr->current_trace->flags->opts;
5187
5188 for (i = 0; trace_options[i]; i++) {
5189 if (tr->trace_flags & (1 << i))
5190 seq_printf(m, "%s\n", trace_options[i]);
5191 else
5192 seq_printf(m, "no%s\n", trace_options[i]);
5193 }
5194
5195 for (i = 0; trace_opts[i].name; i++) {
5196 if (tracer_flags & trace_opts[i].bit)
5197 seq_printf(m, "%s\n", trace_opts[i].name);
5198 else
5199 seq_printf(m, "no%s\n", trace_opts[i].name);
5200 }
5201 mutex_unlock(&trace_types_lock);
5202
5203 return 0;
5204}
5205
5206static int __set_tracer_option(struct trace_array *tr,
5207 struct tracer_flags *tracer_flags,
5208 struct tracer_opt *opts, int neg)
5209{
5210 struct tracer *trace = tracer_flags->trace;
5211 int ret;
5212
5213 ret = trace->set_flag(tr, tracer_flags->val, opts->bit, !neg);
5214 if (ret)
5215 return ret;
5216
5217 if (neg)
5218 tracer_flags->val &= ~opts->bit;
5219 else
5220 tracer_flags->val |= opts->bit;
5221 return 0;
5222}
5223
5224/* Try to assign a tracer specific option */
5225static int set_tracer_option(struct trace_array *tr, char *cmp, int neg)
5226{
5227 struct tracer *trace = tr->current_trace;
5228 struct tracer_flags *tracer_flags = trace->flags;
5229 struct tracer_opt *opts = NULL;
5230 int i;
5231
5232 for (i = 0; tracer_flags->opts[i].name; i++) {
5233 opts = &tracer_flags->opts[i];
5234
5235 if (strcmp(cmp, opts->name) == 0)
5236 return __set_tracer_option(tr, trace->flags, opts, neg);
5237 }
5238
5239 return -EINVAL;
5240}
5241
5242/* Some tracers require overwrite to stay enabled */
5243int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set)
5244{
5245 if (tracer->enabled && (mask & TRACE_ITER_OVERWRITE) && !set)
5246 return -1;
5247
5248 return 0;
5249}
5250
5251int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled)
5252{
5253 int *map;
5254
5255 if ((mask == TRACE_ITER_RECORD_TGID) ||
5256 (mask == TRACE_ITER_RECORD_CMD))
5257 lockdep_assert_held(&event_mutex);
5258
5259 /* do nothing if flag is already set */
5260 if (!!(tr->trace_flags & mask) == !!enabled)
5261 return 0;
5262
5263 /* Give the tracer a chance to approve the change */
5264 if (tr->current_trace->flag_changed)
5265 if (tr->current_trace->flag_changed(tr, mask, !!enabled))
5266 return -EINVAL;
5267
5268 if (enabled)
5269 tr->trace_flags |= mask;
5270 else
5271 tr->trace_flags &= ~mask;
5272
5273 if (mask == TRACE_ITER_RECORD_CMD)
5274 trace_event_enable_cmd_record(enabled);
5275
5276 if (mask == TRACE_ITER_RECORD_TGID) {
5277 if (!tgid_map) {
5278 tgid_map_max = pid_max;
5279 map = kvcalloc(tgid_map_max + 1, sizeof(*tgid_map),
5280 GFP_KERNEL);
5281
5282 /*
5283 * Pairs with smp_load_acquire() in
5284 * trace_find_tgid_ptr() to ensure that if it observes
5285 * the tgid_map we just allocated then it also observes
5286 * the corresponding tgid_map_max value.
5287 */
5288 smp_store_release(&tgid_map, map);
5289 }
5290 if (!tgid_map) {
5291 tr->trace_flags &= ~TRACE_ITER_RECORD_TGID;
5292 return -ENOMEM;
5293 }
5294
5295 trace_event_enable_tgid_record(enabled);
5296 }
5297
5298 if (mask == TRACE_ITER_EVENT_FORK)
5299 trace_event_follow_fork(tr, enabled);
5300
5301 if (mask == TRACE_ITER_FUNC_FORK)
5302 ftrace_pid_follow_fork(tr, enabled);
5303
5304 if (mask == TRACE_ITER_OVERWRITE) {
5305 ring_buffer_change_overwrite(tr->array_buffer.buffer, enabled);
5306#ifdef CONFIG_TRACER_MAX_TRACE
5307 ring_buffer_change_overwrite(tr->max_buffer.buffer, enabled);
5308#endif
5309 }
5310
5311 if (mask == TRACE_ITER_PRINTK) {
5312 trace_printk_start_stop_comm(enabled);
5313 trace_printk_control(enabled);
5314 }
5315
5316 return 0;
5317}
5318
5319int trace_set_options(struct trace_array *tr, char *option)
5320{
5321 char *cmp;
5322 int neg = 0;
5323 int ret;
5324 size_t orig_len = strlen(option);
5325 int len;
5326
5327 cmp = strstrip(option);
5328
5329 len = str_has_prefix(cmp, "no");
5330 if (len)
5331 neg = 1;
5332
5333 cmp += len;
5334
5335 mutex_lock(&event_mutex);
5336 mutex_lock(&trace_types_lock);
5337
5338 ret = match_string(trace_options, -1, cmp);
5339 /* If no option could be set, test the specific tracer options */
5340 if (ret < 0)
5341 ret = set_tracer_option(tr, cmp, neg);
5342 else
5343 ret = set_tracer_flag(tr, 1 << ret, !neg);
5344
5345 mutex_unlock(&trace_types_lock);
5346 mutex_unlock(&event_mutex);
5347
5348 /*
5349 * If the first trailing whitespace is replaced with '\0' by strstrip,
5350 * turn it back into a space.
5351 */
5352 if (orig_len > strlen(option))
5353 option[strlen(option)] = ' ';
5354
5355 return ret;
5356}
5357
5358static void __init apply_trace_boot_options(void)
5359{
5360 char *buf = trace_boot_options_buf;
5361 char *option;
5362
5363 while (true) {
5364 option = strsep(&buf, ",");
5365
5366 if (!option)
5367 break;
5368
5369 if (*option)
5370 trace_set_options(&global_trace, option);
5371
5372 /* Put back the comma to allow this to be called again */
5373 if (buf)
5374 *(buf - 1) = ',';
5375 }
5376}
5377
5378static ssize_t
5379tracing_trace_options_write(struct file *filp, const char __user *ubuf,
5380 size_t cnt, loff_t *ppos)
5381{
5382 struct seq_file *m = filp->private_data;
5383 struct trace_array *tr = m->private;
5384 char buf[64];
5385 int ret;
5386
5387 if (cnt >= sizeof(buf))
5388 return -EINVAL;
5389
5390 if (copy_from_user(buf, ubuf, cnt))
5391 return -EFAULT;
5392
5393 buf[cnt] = 0;
5394
5395 ret = trace_set_options(tr, buf);
5396 if (ret < 0)
5397 return ret;
5398
5399 *ppos += cnt;
5400
5401 return cnt;
5402}
5403
5404static int tracing_trace_options_open(struct inode *inode, struct file *file)
5405{
5406 struct trace_array *tr = inode->i_private;
5407 int ret;
5408
5409 ret = tracing_check_open_get_tr(tr);
5410 if (ret)
5411 return ret;
5412
5413 ret = single_open(file, tracing_trace_options_show, inode->i_private);
5414 if (ret < 0)
5415 trace_array_put(tr);
5416
5417 return ret;
5418}
5419
5420static const struct file_operations tracing_iter_fops = {
5421 .open = tracing_trace_options_open,
5422 .read = seq_read,
5423 .llseek = seq_lseek,
5424 .release = tracing_single_release_tr,
5425 .write = tracing_trace_options_write,
5426};
5427
5428static const char readme_msg[] =
5429 "tracing mini-HOWTO:\n\n"
5430 "# echo 0 > tracing_on : quick way to disable tracing\n"
5431 "# echo 1 > tracing_on : quick way to re-enable tracing\n\n"
5432 " Important files:\n"
5433 " trace\t\t\t- The static contents of the buffer\n"
5434 "\t\t\t To clear the buffer write into this file: echo > trace\n"
5435 " trace_pipe\t\t- A consuming read to see the contents of the buffer\n"
5436 " current_tracer\t- function and latency tracers\n"
5437 " available_tracers\t- list of configured tracers for current_tracer\n"
5438 " error_log\t- error log for failed commands (that support it)\n"
5439 " buffer_size_kb\t- view and modify size of per cpu buffer\n"
5440 " buffer_total_size_kb - view total size of all cpu buffers\n\n"
5441 " trace_clock\t\t-change the clock used to order events\n"
5442 " local: Per cpu clock but may not be synced across CPUs\n"
5443 " global: Synced across CPUs but slows tracing down.\n"
5444 " counter: Not a clock, but just an increment\n"
5445 " uptime: Jiffy counter from time of boot\n"
5446 " perf: Same clock that perf events use\n"
5447#ifdef CONFIG_X86_64
5448 " x86-tsc: TSC cycle counter\n"
5449#endif
5450 "\n timestamp_mode\t-view the mode used to timestamp events\n"
5451 " delta: Delta difference against a buffer-wide timestamp\n"
5452 " absolute: Absolute (standalone) timestamp\n"
5453 "\n trace_marker\t\t- Writes into this file writes into the kernel buffer\n"
5454 "\n trace_marker_raw\t\t- Writes into this file writes binary data into the kernel buffer\n"
5455 " tracing_cpumask\t- Limit which CPUs to trace\n"
5456 " instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
5457 "\t\t\t Remove sub-buffer with rmdir\n"
5458 " trace_options\t\t- Set format or modify how tracing happens\n"
5459 "\t\t\t Disable an option by prefixing 'no' to the\n"
5460 "\t\t\t option name\n"
5461 " saved_cmdlines_size\t- echo command number in here to store comm-pid list\n"
5462#ifdef CONFIG_DYNAMIC_FTRACE
5463 "\n available_filter_functions - list of functions that can be filtered on\n"
5464 " set_ftrace_filter\t- echo function name in here to only trace these\n"
5465 "\t\t\t functions\n"
5466 "\t accepts: func_full_name or glob-matching-pattern\n"
5467 "\t modules: Can select a group via module\n"
5468 "\t Format: :mod:<module-name>\n"
5469 "\t example: echo :mod:ext3 > set_ftrace_filter\n"
5470 "\t triggers: a command to perform when function is hit\n"
5471 "\t Format: <function>:<trigger>[:count]\n"
5472 "\t trigger: traceon, traceoff\n"
5473 "\t\t enable_event:<system>:<event>\n"
5474 "\t\t disable_event:<system>:<event>\n"
5475#ifdef CONFIG_STACKTRACE
5476 "\t\t stacktrace\n"
5477#endif
5478#ifdef CONFIG_TRACER_SNAPSHOT
5479 "\t\t snapshot\n"
5480#endif
5481 "\t\t dump\n"
5482 "\t\t cpudump\n"
5483 "\t example: echo do_fault:traceoff > set_ftrace_filter\n"
5484 "\t echo do_trap:traceoff:3 > set_ftrace_filter\n"
5485 "\t The first one will disable tracing every time do_fault is hit\n"
5486 "\t The second will disable tracing at most 3 times when do_trap is hit\n"
5487 "\t The first time do trap is hit and it disables tracing, the\n"
5488 "\t counter will decrement to 2. If tracing is already disabled,\n"
5489 "\t the counter will not decrement. It only decrements when the\n"
5490 "\t trigger did work\n"
5491 "\t To remove trigger without count:\n"
5492 "\t echo '!<function>:<trigger> > set_ftrace_filter\n"
5493 "\t To remove trigger with a count:\n"
5494 "\t echo '!<function>:<trigger>:0 > set_ftrace_filter\n"
5495 " set_ftrace_notrace\t- echo function name in here to never trace.\n"
5496 "\t accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
5497 "\t modules: Can select a group via module command :mod:\n"
5498 "\t Does not accept triggers\n"
5499#endif /* CONFIG_DYNAMIC_FTRACE */
5500#ifdef CONFIG_FUNCTION_TRACER
5501 " set_ftrace_pid\t- Write pid(s) to only function trace those pids\n"
5502 "\t\t (function)\n"
5503 " set_ftrace_notrace_pid\t- Write pid(s) to not function trace those pids\n"
5504 "\t\t (function)\n"
5505#endif
5506#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5507 " set_graph_function\t- Trace the nested calls of a function (function_graph)\n"
5508 " set_graph_notrace\t- Do not trace the nested calls of a function (function_graph)\n"
5509 " max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n"
5510#endif
5511#ifdef CONFIG_TRACER_SNAPSHOT
5512 "\n snapshot\t\t- Like 'trace' but shows the content of the static\n"
5513 "\t\t\t snapshot buffer. Read the contents for more\n"
5514 "\t\t\t information\n"
5515#endif
5516#ifdef CONFIG_STACK_TRACER
5517 " stack_trace\t\t- Shows the max stack trace when active\n"
5518 " stack_max_size\t- Shows current max stack size that was traced\n"
5519 "\t\t\t Write into this file to reset the max size (trigger a\n"
5520 "\t\t\t new trace)\n"
5521#ifdef CONFIG_DYNAMIC_FTRACE
5522 " stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace\n"
5523 "\t\t\t traces\n"
5524#endif
5525#endif /* CONFIG_STACK_TRACER */
5526#ifdef CONFIG_DYNAMIC_EVENTS
5527 " dynamic_events\t\t- Create/append/remove/show the generic dynamic events\n"
5528 "\t\t\t Write into this file to define/undefine new trace events.\n"
5529#endif
5530#ifdef CONFIG_KPROBE_EVENTS
5531 " kprobe_events\t\t- Create/append/remove/show the kernel dynamic events\n"
5532 "\t\t\t Write into this file to define/undefine new trace events.\n"
5533#endif
5534#ifdef CONFIG_UPROBE_EVENTS
5535 " uprobe_events\t\t- Create/append/remove/show the userspace dynamic events\n"
5536 "\t\t\t Write into this file to define/undefine new trace events.\n"
5537#endif
5538#if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
5539 "\t accepts: event-definitions (one definition per line)\n"
5540 "\t Format: p[:[<group>/]<event>] <place> [<args>]\n"
5541 "\t r[maxactive][:[<group>/]<event>] <place> [<args>]\n"
5542#ifdef CONFIG_HIST_TRIGGERS
5543 "\t s:[synthetic/]<event> <field> [<field>]\n"
5544#endif
5545 "\t -:[<group>/]<event>\n"
5546#ifdef CONFIG_KPROBE_EVENTS
5547 "\t place: [<module>:]<symbol>[+<offset>]|<memaddr>\n"
5548 "place (kretprobe): [<module>:]<symbol>[+<offset>]%return|<memaddr>\n"
5549#endif
5550#ifdef CONFIG_UPROBE_EVENTS
5551 " place (uprobe): <path>:<offset>[%return][(ref_ctr_offset)]\n"
5552#endif
5553 "\t args: <name>=fetcharg[:type]\n"
5554 "\t fetcharg: %<register>, @<address>, @<symbol>[+|-<offset>],\n"
5555#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
5556 "\t $stack<index>, $stack, $retval, $comm, $arg<N>,\n"
5557#else
5558 "\t $stack<index>, $stack, $retval, $comm,\n"
5559#endif
5560 "\t +|-[u]<offset>(<fetcharg>), \\imm-value, \\\"imm-string\"\n"
5561 "\t type: s8/16/32/64, u8/16/32/64, x8/16/32/64, string, symbol,\n"
5562 "\t b<bit-width>@<bit-offset>/<container-size>, ustring,\n"
5563 "\t <type>\\[<array-size>\\]\n"
5564#ifdef CONFIG_HIST_TRIGGERS
5565 "\t field: <stype> <name>;\n"
5566 "\t stype: u8/u16/u32/u64, s8/s16/s32/s64, pid_t,\n"
5567 "\t [unsigned] char/int/long\n"
5568#endif
5569#endif
5570 " events/\t\t- Directory containing all trace event subsystems:\n"
5571 " enable\t\t- Write 0/1 to enable/disable tracing of all events\n"
5572 " events/<system>/\t- Directory containing all trace events for <system>:\n"
5573 " enable\t\t- Write 0/1 to enable/disable tracing of all <system>\n"
5574 "\t\t\t events\n"
5575 " filter\t\t- If set, only events passing filter are traced\n"
5576 " events/<system>/<event>/\t- Directory containing control files for\n"
5577 "\t\t\t <event>:\n"
5578 " enable\t\t- Write 0/1 to enable/disable tracing of <event>\n"
5579 " filter\t\t- If set, only events passing filter are traced\n"
5580 " trigger\t\t- If set, a command to perform when event is hit\n"
5581 "\t Format: <trigger>[:count][if <filter>]\n"
5582 "\t trigger: traceon, traceoff\n"
5583 "\t enable_event:<system>:<event>\n"
5584 "\t disable_event:<system>:<event>\n"
5585#ifdef CONFIG_HIST_TRIGGERS
5586 "\t enable_hist:<system>:<event>\n"
5587 "\t disable_hist:<system>:<event>\n"
5588#endif
5589#ifdef CONFIG_STACKTRACE
5590 "\t\t stacktrace\n"
5591#endif
5592#ifdef CONFIG_TRACER_SNAPSHOT
5593 "\t\t snapshot\n"
5594#endif
5595#ifdef CONFIG_HIST_TRIGGERS
5596 "\t\t hist (see below)\n"
5597#endif
5598 "\t example: echo traceoff > events/block/block_unplug/trigger\n"
5599 "\t echo traceoff:3 > events/block/block_unplug/trigger\n"
5600 "\t echo 'enable_event:kmem:kmalloc:3 if nr_rq > 1' > \\\n"
5601 "\t events/block/block_unplug/trigger\n"
5602 "\t The first disables tracing every time block_unplug is hit.\n"
5603 "\t The second disables tracing the first 3 times block_unplug is hit.\n"
5604 "\t The third enables the kmalloc event the first 3 times block_unplug\n"
5605 "\t is hit and has value of greater than 1 for the 'nr_rq' event field.\n"
5606 "\t Like function triggers, the counter is only decremented if it\n"
5607 "\t enabled or disabled tracing.\n"
5608 "\t To remove a trigger without a count:\n"
5609 "\t echo '!<trigger> > <system>/<event>/trigger\n"
5610 "\t To remove a trigger with a count:\n"
5611 "\t echo '!<trigger>:0 > <system>/<event>/trigger\n"
5612 "\t Filters can be ignored when removing a trigger.\n"
5613#ifdef CONFIG_HIST_TRIGGERS
5614 " hist trigger\t- If set, event hits are aggregated into a hash table\n"
5615 "\t Format: hist:keys=<field1[,field2,...]>\n"
5616 "\t [:values=<field1[,field2,...]>]\n"
5617 "\t [:sort=<field1[,field2,...]>]\n"
5618 "\t [:size=#entries]\n"
5619 "\t [:pause][:continue][:clear]\n"
5620 "\t [:name=histname1]\n"
5621 "\t [:<handler>.<action>]\n"
5622 "\t [if <filter>]\n\n"
5623 "\t Note, special fields can be used as well:\n"
5624 "\t common_timestamp - to record current timestamp\n"
5625 "\t common_cpu - to record the CPU the event happened on\n"
5626 "\n"
5627 "\t When a matching event is hit, an entry is added to a hash\n"
5628 "\t table using the key(s) and value(s) named, and the value of a\n"
5629 "\t sum called 'hitcount' is incremented. Keys and values\n"
5630 "\t correspond to fields in the event's format description. Keys\n"
5631 "\t can be any field, or the special string 'stacktrace'.\n"
5632 "\t Compound keys consisting of up to two fields can be specified\n"
5633 "\t by the 'keys' keyword. Values must correspond to numeric\n"
5634 "\t fields. Sort keys consisting of up to two fields can be\n"
5635 "\t specified using the 'sort' keyword. The sort direction can\n"
5636 "\t be modified by appending '.descending' or '.ascending' to a\n"
5637 "\t sort field. The 'size' parameter can be used to specify more\n"
5638 "\t or fewer than the default 2048 entries for the hashtable size.\n"
5639 "\t If a hist trigger is given a name using the 'name' parameter,\n"
5640 "\t its histogram data will be shared with other triggers of the\n"
5641 "\t same name, and trigger hits will update this common data.\n\n"
5642 "\t Reading the 'hist' file for the event will dump the hash\n"
5643 "\t table in its entirety to stdout. If there are multiple hist\n"
5644 "\t triggers attached to an event, there will be a table for each\n"
5645 "\t trigger in the output. The table displayed for a named\n"
5646 "\t trigger will be the same as any other instance having the\n"
5647 "\t same name. The default format used to display a given field\n"
5648 "\t can be modified by appending any of the following modifiers\n"
5649 "\t to the field name, as applicable:\n\n"
5650 "\t .hex display a number as a hex value\n"
5651 "\t .sym display an address as a symbol\n"
5652 "\t .sym-offset display an address as a symbol and offset\n"
5653 "\t .execname display a common_pid as a program name\n"
5654 "\t .syscall display a syscall id as a syscall name\n"
5655 "\t .log2 display log2 value rather than raw number\n"
5656 "\t .usecs display a common_timestamp in microseconds\n\n"
5657 "\t The 'pause' parameter can be used to pause an existing hist\n"
5658 "\t trigger or to start a hist trigger but not log any events\n"
5659 "\t until told to do so. 'continue' can be used to start or\n"
5660 "\t restart a paused hist trigger.\n\n"
5661 "\t The 'clear' parameter will clear the contents of a running\n"
5662 "\t hist trigger and leave its current paused/active state\n"
5663 "\t unchanged.\n\n"
5664 "\t The enable_hist and disable_hist triggers can be used to\n"
5665 "\t have one event conditionally start and stop another event's\n"
5666 "\t already-attached hist trigger. The syntax is analogous to\n"
5667 "\t the enable_event and disable_event triggers.\n\n"
5668 "\t Hist trigger handlers and actions are executed whenever a\n"
5669 "\t a histogram entry is added or updated. They take the form:\n\n"
5670 "\t <handler>.<action>\n\n"
5671 "\t The available handlers are:\n\n"
5672 "\t onmatch(matching.event) - invoke on addition or update\n"
5673 "\t onmax(var) - invoke if var exceeds current max\n"
5674 "\t onchange(var) - invoke action if var changes\n\n"
5675 "\t The available actions are:\n\n"
5676 "\t trace(<synthetic_event>,param list) - generate synthetic event\n"
5677 "\t save(field,...) - save current event fields\n"
5678#ifdef CONFIG_TRACER_SNAPSHOT
5679 "\t snapshot() - snapshot the trace buffer\n\n"
5680#endif
5681#ifdef CONFIG_SYNTH_EVENTS
5682 " events/synthetic_events\t- Create/append/remove/show synthetic events\n"
5683 "\t Write into this file to define/undefine new synthetic events.\n"
5684 "\t example: echo 'myevent u64 lat; char name[]' >> synthetic_events\n"
5685#endif
5686#endif
5687;
5688
5689static ssize_t
5690tracing_readme_read(struct file *filp, char __user *ubuf,
5691 size_t cnt, loff_t *ppos)
5692{
5693 return simple_read_from_buffer(ubuf, cnt, ppos,
5694 readme_msg, strlen(readme_msg));
5695}
5696
5697static const struct file_operations tracing_readme_fops = {
5698 .open = tracing_open_generic,
5699 .read = tracing_readme_read,
5700 .llseek = generic_file_llseek,
5701};
5702
5703static void *saved_tgids_next(struct seq_file *m, void *v, loff_t *pos)
5704{
5705 int pid = ++(*pos);
5706
5707 return trace_find_tgid_ptr(pid);
5708}
5709
5710static void *saved_tgids_start(struct seq_file *m, loff_t *pos)
5711{
5712 int pid = *pos;
5713
5714 return trace_find_tgid_ptr(pid);
5715}
5716
5717static void saved_tgids_stop(struct seq_file *m, void *v)
5718{
5719}
5720
5721static int saved_tgids_show(struct seq_file *m, void *v)
5722{
5723 int *entry = (int *)v;
5724 int pid = entry - tgid_map;
5725 int tgid = *entry;
5726
5727 if (tgid == 0)
5728 return SEQ_SKIP;
5729
5730 seq_printf(m, "%d %d\n", pid, tgid);
5731 return 0;
5732}
5733
5734static const struct seq_operations tracing_saved_tgids_seq_ops = {
5735 .start = saved_tgids_start,
5736 .stop = saved_tgids_stop,
5737 .next = saved_tgids_next,
5738 .show = saved_tgids_show,
5739};
5740
5741static int tracing_saved_tgids_open(struct inode *inode, struct file *filp)
5742{
5743 int ret;
5744
5745 ret = tracing_check_open_get_tr(NULL);
5746 if (ret)
5747 return ret;
5748
5749 return seq_open(filp, &tracing_saved_tgids_seq_ops);
5750}
5751
5752
5753static const struct file_operations tracing_saved_tgids_fops = {
5754 .open = tracing_saved_tgids_open,
5755 .read = seq_read,
5756 .llseek = seq_lseek,
5757 .release = seq_release,
5758};
5759
5760static void *saved_cmdlines_next(struct seq_file *m, void *v, loff_t *pos)
5761{
5762 unsigned int *ptr = v;
5763
5764 if (*pos || m->count)
5765 ptr++;
5766
5767 (*pos)++;
5768
5769 for (; ptr < &savedcmd->map_cmdline_to_pid[savedcmd->cmdline_num];
5770 ptr++) {
5771 if (*ptr == -1 || *ptr == NO_CMDLINE_MAP)
5772 continue;
5773
5774 return ptr;
5775 }
5776
5777 return NULL;
5778}
5779
5780static void *saved_cmdlines_start(struct seq_file *m, loff_t *pos)
5781{
5782 void *v;
5783 loff_t l = 0;
5784
5785 preempt_disable();
5786 arch_spin_lock(&trace_cmdline_lock);
5787
5788 v = &savedcmd->map_cmdline_to_pid[0];
5789 while (l <= *pos) {
5790 v = saved_cmdlines_next(m, v, &l);
5791 if (!v)
5792 return NULL;
5793 }
5794
5795 return v;
5796}
5797
5798static void saved_cmdlines_stop(struct seq_file *m, void *v)
5799{
5800 arch_spin_unlock(&trace_cmdline_lock);
5801 preempt_enable();
5802}
5803
5804static int saved_cmdlines_show(struct seq_file *m, void *v)
5805{
5806 char buf[TASK_COMM_LEN];
5807 unsigned int *pid = v;
5808
5809 __trace_find_cmdline(*pid, buf);
5810 seq_printf(m, "%d %s\n", *pid, buf);
5811 return 0;
5812}
5813
5814static const struct seq_operations tracing_saved_cmdlines_seq_ops = {
5815 .start = saved_cmdlines_start,
5816 .next = saved_cmdlines_next,
5817 .stop = saved_cmdlines_stop,
5818 .show = saved_cmdlines_show,
5819};
5820
5821static int tracing_saved_cmdlines_open(struct inode *inode, struct file *filp)
5822{
5823 int ret;
5824
5825 ret = tracing_check_open_get_tr(NULL);
5826 if (ret)
5827 return ret;
5828
5829 return seq_open(filp, &tracing_saved_cmdlines_seq_ops);
5830}
5831
5832static const struct file_operations tracing_saved_cmdlines_fops = {
5833 .open = tracing_saved_cmdlines_open,
5834 .read = seq_read,
5835 .llseek = seq_lseek,
5836 .release = seq_release,
5837};
5838
5839static ssize_t
5840tracing_saved_cmdlines_size_read(struct file *filp, char __user *ubuf,
5841 size_t cnt, loff_t *ppos)
5842{
5843 char buf[64];
5844 int r;
5845
5846 arch_spin_lock(&trace_cmdline_lock);
5847 r = scnprintf(buf, sizeof(buf), "%u\n", savedcmd->cmdline_num);
5848 arch_spin_unlock(&trace_cmdline_lock);
5849
5850 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
5851}
5852
5853static void free_saved_cmdlines_buffer(struct saved_cmdlines_buffer *s)
5854{
5855 kfree(s->saved_cmdlines);
5856 kfree(s->map_cmdline_to_pid);
5857 kfree(s);
5858}
5859
5860static int tracing_resize_saved_cmdlines(unsigned int val)
5861{
5862 struct saved_cmdlines_buffer *s, *savedcmd_temp;
5863
5864 s = kmalloc(sizeof(*s), GFP_KERNEL);
5865 if (!s)
5866 return -ENOMEM;
5867
5868 if (allocate_cmdlines_buffer(val, s) < 0) {
5869 kfree(s);
5870 return -ENOMEM;
5871 }
5872
5873 arch_spin_lock(&trace_cmdline_lock);
5874 savedcmd_temp = savedcmd;
5875 savedcmd = s;
5876 arch_spin_unlock(&trace_cmdline_lock);
5877 free_saved_cmdlines_buffer(savedcmd_temp);
5878
5879 return 0;
5880}
5881
5882static ssize_t
5883tracing_saved_cmdlines_size_write(struct file *filp, const char __user *ubuf,
5884 size_t cnt, loff_t *ppos)
5885{
5886 unsigned long val;
5887 int ret;
5888
5889 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
5890 if (ret)
5891 return ret;
5892
5893 /* must have at least 1 entry or less than PID_MAX_DEFAULT */
5894 if (!val || val > PID_MAX_DEFAULT)
5895 return -EINVAL;
5896
5897 ret = tracing_resize_saved_cmdlines((unsigned int)val);
5898 if (ret < 0)
5899 return ret;
5900
5901 *ppos += cnt;
5902
5903 return cnt;
5904}
5905
5906static const struct file_operations tracing_saved_cmdlines_size_fops = {
5907 .open = tracing_open_generic,
5908 .read = tracing_saved_cmdlines_size_read,
5909 .write = tracing_saved_cmdlines_size_write,
5910};
5911
5912#ifdef CONFIG_TRACE_EVAL_MAP_FILE
5913static union trace_eval_map_item *
5914update_eval_map(union trace_eval_map_item *ptr)
5915{
5916 if (!ptr->map.eval_string) {
5917 if (ptr->tail.next) {
5918 ptr = ptr->tail.next;
5919 /* Set ptr to the next real item (skip head) */
5920 ptr++;
5921 } else
5922 return NULL;
5923 }
5924 return ptr;
5925}
5926
5927static void *eval_map_next(struct seq_file *m, void *v, loff_t *pos)
5928{
5929 union trace_eval_map_item *ptr = v;
5930
5931 /*
5932 * Paranoid! If ptr points to end, we don't want to increment past it.
5933 * This really should never happen.
5934 */
5935 (*pos)++;
5936 ptr = update_eval_map(ptr);
5937 if (WARN_ON_ONCE(!ptr))
5938 return NULL;
5939
5940 ptr++;
5941 ptr = update_eval_map(ptr);
5942
5943 return ptr;
5944}
5945
5946static void *eval_map_start(struct seq_file *m, loff_t *pos)
5947{
5948 union trace_eval_map_item *v;
5949 loff_t l = 0;
5950
5951 mutex_lock(&trace_eval_mutex);
5952
5953 v = trace_eval_maps;
5954 if (v)
5955 v++;
5956
5957 while (v && l < *pos) {
5958 v = eval_map_next(m, v, &l);
5959 }
5960
5961 return v;
5962}
5963
5964static void eval_map_stop(struct seq_file *m, void *v)
5965{
5966 mutex_unlock(&trace_eval_mutex);
5967}
5968
5969static int eval_map_show(struct seq_file *m, void *v)
5970{
5971 union trace_eval_map_item *ptr = v;
5972
5973 seq_printf(m, "%s %ld (%s)\n",
5974 ptr->map.eval_string, ptr->map.eval_value,
5975 ptr->map.system);
5976
5977 return 0;
5978}
5979
5980static const struct seq_operations tracing_eval_map_seq_ops = {
5981 .start = eval_map_start,
5982 .next = eval_map_next,
5983 .stop = eval_map_stop,
5984 .show = eval_map_show,
5985};
5986
5987static int tracing_eval_map_open(struct inode *inode, struct file *filp)
5988{
5989 int ret;
5990
5991 ret = tracing_check_open_get_tr(NULL);
5992 if (ret)
5993 return ret;
5994
5995 return seq_open(filp, &tracing_eval_map_seq_ops);
5996}
5997
5998static const struct file_operations tracing_eval_map_fops = {
5999 .open = tracing_eval_map_open,
6000 .read = seq_read,
6001 .llseek = seq_lseek,
6002 .release = seq_release,
6003};
6004
6005static inline union trace_eval_map_item *
6006trace_eval_jmp_to_tail(union trace_eval_map_item *ptr)
6007{
6008 /* Return tail of array given the head */
6009 return ptr + ptr->head.length + 1;
6010}
6011
6012static void
6013trace_insert_eval_map_file(struct module *mod, struct trace_eval_map **start,
6014 int len)
6015{
6016 struct trace_eval_map **stop;
6017 struct trace_eval_map **map;
6018 union trace_eval_map_item *map_array;
6019 union trace_eval_map_item *ptr;
6020
6021 stop = start + len;
6022
6023 /*
6024 * The trace_eval_maps contains the map plus a head and tail item,
6025 * where the head holds the module and length of array, and the
6026 * tail holds a pointer to the next list.
6027 */
6028 map_array = kmalloc_array(len + 2, sizeof(*map_array), GFP_KERNEL);
6029 if (!map_array) {
6030 pr_warn("Unable to allocate trace eval mapping\n");
6031 return;
6032 }
6033
6034 mutex_lock(&trace_eval_mutex);
6035
6036 if (!trace_eval_maps)
6037 trace_eval_maps = map_array;
6038 else {
6039 ptr = trace_eval_maps;
6040 for (;;) {
6041 ptr = trace_eval_jmp_to_tail(ptr);
6042 if (!ptr->tail.next)
6043 break;
6044 ptr = ptr->tail.next;
6045
6046 }
6047 ptr->tail.next = map_array;
6048 }
6049 map_array->head.mod = mod;
6050 map_array->head.length = len;
6051 map_array++;
6052
6053 for (map = start; (unsigned long)map < (unsigned long)stop; map++) {
6054 map_array->map = **map;
6055 map_array++;
6056 }
6057 memset(map_array, 0, sizeof(*map_array));
6058
6059 mutex_unlock(&trace_eval_mutex);
6060}
6061
6062static void trace_create_eval_file(struct dentry *d_tracer)
6063{
6064 trace_create_file("eval_map", 0444, d_tracer,
6065 NULL, &tracing_eval_map_fops);
6066}
6067
6068#else /* CONFIG_TRACE_EVAL_MAP_FILE */
6069static inline void trace_create_eval_file(struct dentry *d_tracer) { }
6070static inline void trace_insert_eval_map_file(struct module *mod,
6071 struct trace_eval_map **start, int len) { }
6072#endif /* !CONFIG_TRACE_EVAL_MAP_FILE */
6073
6074static void trace_insert_eval_map(struct module *mod,
6075 struct trace_eval_map **start, int len)
6076{
6077 struct trace_eval_map **map;
6078
6079 if (len <= 0)
6080 return;
6081
6082 map = start;
6083
6084 trace_event_eval_update(map, len);
6085
6086 trace_insert_eval_map_file(mod, start, len);
6087}
6088
6089static ssize_t
6090tracing_set_trace_read(struct file *filp, char __user *ubuf,
6091 size_t cnt, loff_t *ppos)
6092{
6093 struct trace_array *tr = filp->private_data;
6094 char buf[MAX_TRACER_SIZE+2];
6095 int r;
6096
6097 mutex_lock(&trace_types_lock);
6098 r = sprintf(buf, "%s\n", tr->current_trace->name);
6099 mutex_unlock(&trace_types_lock);
6100
6101 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6102}
6103
6104int tracer_init(struct tracer *t, struct trace_array *tr)
6105{
6106 tracing_reset_online_cpus(&tr->array_buffer);
6107 return t->init(tr);
6108}
6109
6110static void set_buffer_entries(struct array_buffer *buf, unsigned long val)
6111{
6112 int cpu;
6113
6114 for_each_tracing_cpu(cpu)
6115 per_cpu_ptr(buf->data, cpu)->entries = val;
6116}
6117
6118#ifdef CONFIG_TRACER_MAX_TRACE
6119/* resize @tr's buffer to the size of @size_tr's entries */
6120static int resize_buffer_duplicate_size(struct array_buffer *trace_buf,
6121 struct array_buffer *size_buf, int cpu_id)
6122{
6123 int cpu, ret = 0;
6124
6125 if (cpu_id == RING_BUFFER_ALL_CPUS) {
6126 for_each_tracing_cpu(cpu) {
6127 ret = ring_buffer_resize(trace_buf->buffer,
6128 per_cpu_ptr(size_buf->data, cpu)->entries, cpu);
6129 if (ret < 0)
6130 break;
6131 per_cpu_ptr(trace_buf->data, cpu)->entries =
6132 per_cpu_ptr(size_buf->data, cpu)->entries;
6133 }
6134 } else {
6135 ret = ring_buffer_resize(trace_buf->buffer,
6136 per_cpu_ptr(size_buf->data, cpu_id)->entries, cpu_id);
6137 if (ret == 0)
6138 per_cpu_ptr(trace_buf->data, cpu_id)->entries =
6139 per_cpu_ptr(size_buf->data, cpu_id)->entries;
6140 }
6141
6142 return ret;
6143}
6144#endif /* CONFIG_TRACER_MAX_TRACE */
6145
6146static int __tracing_resize_ring_buffer(struct trace_array *tr,
6147 unsigned long size, int cpu)
6148{
6149 int ret;
6150
6151 /*
6152 * If kernel or user changes the size of the ring buffer
6153 * we use the size that was given, and we can forget about
6154 * expanding it later.
6155 */
6156 ring_buffer_expanded = true;
6157
6158 /* May be called before buffers are initialized */
6159 if (!tr->array_buffer.buffer)
6160 return 0;
6161
6162 ret = ring_buffer_resize(tr->array_buffer.buffer, size, cpu);
6163 if (ret < 0)
6164 return ret;
6165
6166#ifdef CONFIG_TRACER_MAX_TRACE
6167 if (!(tr->flags & TRACE_ARRAY_FL_GLOBAL) ||
6168 !tr->current_trace->use_max_tr)
6169 goto out;
6170
6171 ret = ring_buffer_resize(tr->max_buffer.buffer, size, cpu);
6172 if (ret < 0) {
6173 int r = resize_buffer_duplicate_size(&tr->array_buffer,
6174 &tr->array_buffer, cpu);
6175 if (r < 0) {
6176 /*
6177 * AARGH! We are left with different
6178 * size max buffer!!!!
6179 * The max buffer is our "snapshot" buffer.
6180 * When a tracer needs a snapshot (one of the
6181 * latency tracers), it swaps the max buffer
6182 * with the saved snap shot. We succeeded to
6183 * update the size of the main buffer, but failed to
6184 * update the size of the max buffer. But when we tried
6185 * to reset the main buffer to the original size, we
6186 * failed there too. This is very unlikely to
6187 * happen, but if it does, warn and kill all
6188 * tracing.
6189 */
6190 WARN_ON(1);
6191 tracing_disabled = 1;
6192 }
6193 return ret;
6194 }
6195
6196 if (cpu == RING_BUFFER_ALL_CPUS)
6197 set_buffer_entries(&tr->max_buffer, size);
6198 else
6199 per_cpu_ptr(tr->max_buffer.data, cpu)->entries = size;
6200
6201 out:
6202#endif /* CONFIG_TRACER_MAX_TRACE */
6203
6204 if (cpu == RING_BUFFER_ALL_CPUS)
6205 set_buffer_entries(&tr->array_buffer, size);
6206 else
6207 per_cpu_ptr(tr->array_buffer.data, cpu)->entries = size;
6208
6209 return ret;
6210}
6211
6212ssize_t tracing_resize_ring_buffer(struct trace_array *tr,
6213 unsigned long size, int cpu_id)
6214{
6215 int ret;
6216
6217 mutex_lock(&trace_types_lock);
6218
6219 if (cpu_id != RING_BUFFER_ALL_CPUS) {
6220 /* make sure, this cpu is enabled in the mask */
6221 if (!cpumask_test_cpu(cpu_id, tracing_buffer_mask)) {
6222 ret = -EINVAL;
6223 goto out;
6224 }
6225 }
6226
6227 ret = __tracing_resize_ring_buffer(tr, size, cpu_id);
6228 if (ret < 0)
6229 ret = -ENOMEM;
6230
6231out:
6232 mutex_unlock(&trace_types_lock);
6233
6234 return ret;
6235}
6236
6237
6238/**
6239 * tracing_update_buffers - used by tracing facility to expand ring buffers
6240 *
6241 * To save on memory when the tracing is never used on a system with it
6242 * configured in. The ring buffers are set to a minimum size. But once
6243 * a user starts to use the tracing facility, then they need to grow
6244 * to their default size.
6245 *
6246 * This function is to be called when a tracer is about to be used.
6247 */
6248int tracing_update_buffers(void)
6249{
6250 int ret = 0;
6251
6252 mutex_lock(&trace_types_lock);
6253 if (!ring_buffer_expanded)
6254 ret = __tracing_resize_ring_buffer(&global_trace, trace_buf_size,
6255 RING_BUFFER_ALL_CPUS);
6256 mutex_unlock(&trace_types_lock);
6257
6258 return ret;
6259}
6260
6261struct trace_option_dentry;
6262
6263static void
6264create_trace_option_files(struct trace_array *tr, struct tracer *tracer);
6265
6266/*
6267 * Used to clear out the tracer before deletion of an instance.
6268 * Must have trace_types_lock held.
6269 */
6270static void tracing_set_nop(struct trace_array *tr)
6271{
6272 if (tr->current_trace == &nop_trace)
6273 return;
6274
6275 tr->current_trace->enabled--;
6276
6277 if (tr->current_trace->reset)
6278 tr->current_trace->reset(tr);
6279
6280 tr->current_trace = &nop_trace;
6281}
6282
6283static void add_tracer_options(struct trace_array *tr, struct tracer *t)
6284{
6285 /* Only enable if the directory has been created already. */
6286 if (!tr->dir)
6287 return;
6288
6289 create_trace_option_files(tr, t);
6290}
6291
6292int tracing_set_tracer(struct trace_array *tr, const char *buf)
6293{
6294 struct tracer *t;
6295#ifdef CONFIG_TRACER_MAX_TRACE
6296 bool had_max_tr;
6297#endif
6298 int ret = 0;
6299
6300 mutex_lock(&trace_types_lock);
6301
6302 if (!ring_buffer_expanded) {
6303 ret = __tracing_resize_ring_buffer(tr, trace_buf_size,
6304 RING_BUFFER_ALL_CPUS);
6305 if (ret < 0)
6306 goto out;
6307 ret = 0;
6308 }
6309
6310 for (t = trace_types; t; t = t->next) {
6311 if (strcmp(t->name, buf) == 0)
6312 break;
6313 }
6314 if (!t) {
6315 ret = -EINVAL;
6316 goto out;
6317 }
6318 if (t == tr->current_trace)
6319 goto out;
6320
6321#ifdef CONFIG_TRACER_SNAPSHOT
6322 if (t->use_max_tr) {
6323 arch_spin_lock(&tr->max_lock);
6324 if (tr->cond_snapshot)
6325 ret = -EBUSY;
6326 arch_spin_unlock(&tr->max_lock);
6327 if (ret)
6328 goto out;
6329 }
6330#endif
6331 /* Some tracers won't work on kernel command line */
6332 if (system_state < SYSTEM_RUNNING && t->noboot) {
6333 pr_warn("Tracer '%s' is not allowed on command line, ignored\n",
6334 t->name);
6335 goto out;
6336 }
6337
6338 /* Some tracers are only allowed for the top level buffer */
6339 if (!trace_ok_for_array(t, tr)) {
6340 ret = -EINVAL;
6341 goto out;
6342 }
6343
6344 /* If trace pipe files are being read, we can't change the tracer */
6345 if (tr->trace_ref) {
6346 ret = -EBUSY;
6347 goto out;
6348 }
6349
6350 trace_branch_disable();
6351
6352 tr->current_trace->enabled--;
6353
6354 if (tr->current_trace->reset)
6355 tr->current_trace->reset(tr);
6356
6357 /* Current trace needs to be nop_trace before synchronize_rcu */
6358 tr->current_trace = &nop_trace;
6359
6360#ifdef CONFIG_TRACER_MAX_TRACE
6361 had_max_tr = tr->allocated_snapshot;
6362
6363 if (had_max_tr && !t->use_max_tr) {
6364 /*
6365 * We need to make sure that the update_max_tr sees that
6366 * current_trace changed to nop_trace to keep it from
6367 * swapping the buffers after we resize it.
6368 * The update_max_tr is called from interrupts disabled
6369 * so a synchronized_sched() is sufficient.
6370 */
6371 synchronize_rcu();
6372 free_snapshot(tr);
6373 }
6374#endif
6375
6376#ifdef CONFIG_TRACER_MAX_TRACE
6377 if (t->use_max_tr && !had_max_tr) {
6378 ret = tracing_alloc_snapshot_instance(tr);
6379 if (ret < 0)
6380 goto out;
6381 }
6382#endif
6383
6384 if (t->init) {
6385 ret = tracer_init(t, tr);
6386 if (ret)
6387 goto out;
6388 }
6389
6390 tr->current_trace = t;
6391 tr->current_trace->enabled++;
6392 trace_branch_enable(tr);
6393 out:
6394 mutex_unlock(&trace_types_lock);
6395
6396 return ret;
6397}
6398
6399static ssize_t
6400tracing_set_trace_write(struct file *filp, const char __user *ubuf,
6401 size_t cnt, loff_t *ppos)
6402{
6403 struct trace_array *tr = filp->private_data;
6404 char buf[MAX_TRACER_SIZE+1];
6405 int i;
6406 size_t ret;
6407 int err;
6408
6409 ret = cnt;
6410
6411 if (cnt > MAX_TRACER_SIZE)
6412 cnt = MAX_TRACER_SIZE;
6413
6414 if (copy_from_user(buf, ubuf, cnt))
6415 return -EFAULT;
6416
6417 buf[cnt] = 0;
6418
6419 /* strip ending whitespace. */
6420 for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
6421 buf[i] = 0;
6422
6423 err = tracing_set_tracer(tr, buf);
6424 if (err)
6425 return err;
6426
6427 *ppos += ret;
6428
6429 return ret;
6430}
6431
6432static ssize_t
6433tracing_nsecs_read(unsigned long *ptr, char __user *ubuf,
6434 size_t cnt, loff_t *ppos)
6435{
6436 char buf[64];
6437 int r;
6438
6439 r = snprintf(buf, sizeof(buf), "%ld\n",
6440 *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
6441 if (r > sizeof(buf))
6442 r = sizeof(buf);
6443 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6444}
6445
6446static ssize_t
6447tracing_nsecs_write(unsigned long *ptr, const char __user *ubuf,
6448 size_t cnt, loff_t *ppos)
6449{
6450 unsigned long val;
6451 int ret;
6452
6453 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6454 if (ret)
6455 return ret;
6456
6457 *ptr = val * 1000;
6458
6459 return cnt;
6460}
6461
6462static ssize_t
6463tracing_thresh_read(struct file *filp, char __user *ubuf,
6464 size_t cnt, loff_t *ppos)
6465{
6466 return tracing_nsecs_read(&tracing_thresh, ubuf, cnt, ppos);
6467}
6468
6469static ssize_t
6470tracing_thresh_write(struct file *filp, const char __user *ubuf,
6471 size_t cnt, loff_t *ppos)
6472{
6473 struct trace_array *tr = filp->private_data;
6474 int ret;
6475
6476 mutex_lock(&trace_types_lock);
6477 ret = tracing_nsecs_write(&tracing_thresh, ubuf, cnt, ppos);
6478 if (ret < 0)
6479 goto out;
6480
6481 if (tr->current_trace->update_thresh) {
6482 ret = tr->current_trace->update_thresh(tr);
6483 if (ret < 0)
6484 goto out;
6485 }
6486
6487 ret = cnt;
6488out:
6489 mutex_unlock(&trace_types_lock);
6490
6491 return ret;
6492}
6493
6494#if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)
6495
6496static ssize_t
6497tracing_max_lat_read(struct file *filp, char __user *ubuf,
6498 size_t cnt, loff_t *ppos)
6499{
6500 return tracing_nsecs_read(filp->private_data, ubuf, cnt, ppos);
6501}
6502
6503static ssize_t
6504tracing_max_lat_write(struct file *filp, const char __user *ubuf,
6505 size_t cnt, loff_t *ppos)
6506{
6507 return tracing_nsecs_write(filp->private_data, ubuf, cnt, ppos);
6508}
6509
6510#endif
6511
6512static int tracing_open_pipe(struct inode *inode, struct file *filp)
6513{
6514 struct trace_array *tr = inode->i_private;
6515 struct trace_iterator *iter;
6516 int ret;
6517
6518 ret = tracing_check_open_get_tr(tr);
6519 if (ret)
6520 return ret;
6521
6522 mutex_lock(&trace_types_lock);
6523
6524 /* create a buffer to store the information to pass to userspace */
6525 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
6526 if (!iter) {
6527 ret = -ENOMEM;
6528 __trace_array_put(tr);
6529 goto out;
6530 }
6531
6532 trace_seq_init(&iter->seq);
6533 iter->trace = tr->current_trace;
6534
6535 if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
6536 ret = -ENOMEM;
6537 goto fail;
6538 }
6539
6540 /* trace pipe does not show start of buffer */
6541 cpumask_setall(iter->started);
6542
6543 if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
6544 iter->iter_flags |= TRACE_FILE_LAT_FMT;
6545
6546 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
6547 if (trace_clocks[tr->clock_id].in_ns)
6548 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
6549
6550 iter->tr = tr;
6551 iter->array_buffer = &tr->array_buffer;
6552 iter->cpu_file = tracing_get_cpu(inode);
6553 mutex_init(&iter->mutex);
6554 filp->private_data = iter;
6555
6556 if (iter->trace->pipe_open)
6557 iter->trace->pipe_open(iter);
6558
6559 nonseekable_open(inode, filp);
6560
6561 tr->trace_ref++;
6562out:
6563 mutex_unlock(&trace_types_lock);
6564 return ret;
6565
6566fail:
6567 kfree(iter);
6568 __trace_array_put(tr);
6569 mutex_unlock(&trace_types_lock);
6570 return ret;
6571}
6572
6573static int tracing_release_pipe(struct inode *inode, struct file *file)
6574{
6575 struct trace_iterator *iter = file->private_data;
6576 struct trace_array *tr = inode->i_private;
6577
6578 mutex_lock(&trace_types_lock);
6579
6580 tr->trace_ref--;
6581
6582 if (iter->trace->pipe_close)
6583 iter->trace->pipe_close(iter);
6584
6585 mutex_unlock(&trace_types_lock);
6586
6587 free_cpumask_var(iter->started);
6588 mutex_destroy(&iter->mutex);
6589 kfree(iter);
6590
6591 trace_array_put(tr);
6592
6593 return 0;
6594}
6595
6596static __poll_t
6597trace_poll(struct trace_iterator *iter, struct file *filp, poll_table *poll_table)
6598{
6599 struct trace_array *tr = iter->tr;
6600
6601 /* Iterators are static, they should be filled or empty */
6602 if (trace_buffer_iter(iter, iter->cpu_file))
6603 return EPOLLIN | EPOLLRDNORM;
6604
6605 if (tr->trace_flags & TRACE_ITER_BLOCK)
6606 /*
6607 * Always select as readable when in blocking mode
6608 */
6609 return EPOLLIN | EPOLLRDNORM;
6610 else
6611 return ring_buffer_poll_wait(iter->array_buffer->buffer, iter->cpu_file,
6612 filp, poll_table);
6613}
6614
6615static __poll_t
6616tracing_poll_pipe(struct file *filp, poll_table *poll_table)
6617{
6618 struct trace_iterator *iter = filp->private_data;
6619
6620 return trace_poll(iter, filp, poll_table);
6621}
6622
6623/* Must be called with iter->mutex held. */
6624static int tracing_wait_pipe(struct file *filp)
6625{
6626 struct trace_iterator *iter = filp->private_data;
6627 int ret;
6628
6629 while (trace_empty(iter)) {
6630
6631 if ((filp->f_flags & O_NONBLOCK)) {
6632 return -EAGAIN;
6633 }
6634
6635 /*
6636 * We block until we read something and tracing is disabled.
6637 * We still block if tracing is disabled, but we have never
6638 * read anything. This allows a user to cat this file, and
6639 * then enable tracing. But after we have read something,
6640 * we give an EOF when tracing is again disabled.
6641 *
6642 * iter->pos will be 0 if we haven't read anything.
6643 */
6644 if (!tracer_tracing_is_on(iter->tr) && iter->pos)
6645 break;
6646
6647 mutex_unlock(&iter->mutex);
6648
6649 ret = wait_on_pipe(iter, 0);
6650
6651 mutex_lock(&iter->mutex);
6652
6653 if (ret)
6654 return ret;
6655 }
6656
6657 return 1;
6658}
6659
6660/*
6661 * Consumer reader.
6662 */
6663static ssize_t
6664tracing_read_pipe(struct file *filp, char __user *ubuf,
6665 size_t cnt, loff_t *ppos)
6666{
6667 struct trace_iterator *iter = filp->private_data;
6668 ssize_t sret;
6669
6670 /*
6671 * Avoid more than one consumer on a single file descriptor
6672 * This is just a matter of traces coherency, the ring buffer itself
6673 * is protected.
6674 */
6675 mutex_lock(&iter->mutex);
6676
6677 /* return any leftover data */
6678 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
6679 if (sret != -EBUSY)
6680 goto out;
6681
6682 trace_seq_init(&iter->seq);
6683
6684 if (iter->trace->read) {
6685 sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
6686 if (sret)
6687 goto out;
6688 }
6689
6690waitagain:
6691 sret = tracing_wait_pipe(filp);
6692 if (sret <= 0)
6693 goto out;
6694
6695 /* stop when tracing is finished */
6696 if (trace_empty(iter)) {
6697 sret = 0;
6698 goto out;
6699 }
6700
6701 if (cnt >= PAGE_SIZE)
6702 cnt = PAGE_SIZE - 1;
6703
6704 /* reset all but tr, trace, and overruns */
6705 memset(&iter->seq, 0,
6706 sizeof(struct trace_iterator) -
6707 offsetof(struct trace_iterator, seq));
6708 cpumask_clear(iter->started);
6709 trace_seq_init(&iter->seq);
6710 iter->pos = -1;
6711
6712 trace_event_read_lock();
6713 trace_access_lock(iter->cpu_file);
6714 while (trace_find_next_entry_inc(iter) != NULL) {
6715 enum print_line_t ret;
6716 int save_len = iter->seq.seq.len;
6717
6718 ret = print_trace_line(iter);
6719 if (ret == TRACE_TYPE_PARTIAL_LINE) {
6720 /* don't print partial lines */
6721 iter->seq.seq.len = save_len;
6722 break;
6723 }
6724 if (ret != TRACE_TYPE_NO_CONSUME)
6725 trace_consume(iter);
6726
6727 if (trace_seq_used(&iter->seq) >= cnt)
6728 break;
6729
6730 /*
6731 * Setting the full flag means we reached the trace_seq buffer
6732 * size and we should leave by partial output condition above.
6733 * One of the trace_seq_* functions is not used properly.
6734 */
6735 WARN_ONCE(iter->seq.full, "full flag set for trace type %d",
6736 iter->ent->type);
6737 }
6738 trace_access_unlock(iter->cpu_file);
6739 trace_event_read_unlock();
6740
6741 /* Now copy what we have to the user */
6742 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
6743 if (iter->seq.seq.readpos >= trace_seq_used(&iter->seq))
6744 trace_seq_init(&iter->seq);
6745
6746 /*
6747 * If there was nothing to send to user, in spite of consuming trace
6748 * entries, go back to wait for more entries.
6749 */
6750 if (sret == -EBUSY)
6751 goto waitagain;
6752
6753out:
6754 mutex_unlock(&iter->mutex);
6755
6756 return sret;
6757}
6758
6759static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
6760 unsigned int idx)
6761{
6762 __free_page(spd->pages[idx]);
6763}
6764
6765static size_t
6766tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
6767{
6768 size_t count;
6769 int save_len;
6770 int ret;
6771
6772 /* Seq buffer is page-sized, exactly what we need. */
6773 for (;;) {
6774 save_len = iter->seq.seq.len;
6775 ret = print_trace_line(iter);
6776
6777 if (trace_seq_has_overflowed(&iter->seq)) {
6778 iter->seq.seq.len = save_len;
6779 break;
6780 }
6781
6782 /*
6783 * This should not be hit, because it should only
6784 * be set if the iter->seq overflowed. But check it
6785 * anyway to be safe.
6786 */
6787 if (ret == TRACE_TYPE_PARTIAL_LINE) {
6788 iter->seq.seq.len = save_len;
6789 break;
6790 }
6791
6792 count = trace_seq_used(&iter->seq) - save_len;
6793 if (rem < count) {
6794 rem = 0;
6795 iter->seq.seq.len = save_len;
6796 break;
6797 }
6798
6799 if (ret != TRACE_TYPE_NO_CONSUME)
6800 trace_consume(iter);
6801 rem -= count;
6802 if (!trace_find_next_entry_inc(iter)) {
6803 rem = 0;
6804 iter->ent = NULL;
6805 break;
6806 }
6807 }
6808
6809 return rem;
6810}
6811
6812static ssize_t tracing_splice_read_pipe(struct file *filp,
6813 loff_t *ppos,
6814 struct pipe_inode_info *pipe,
6815 size_t len,
6816 unsigned int flags)
6817{
6818 struct page *pages_def[PIPE_DEF_BUFFERS];
6819 struct partial_page partial_def[PIPE_DEF_BUFFERS];
6820 struct trace_iterator *iter = filp->private_data;
6821 struct splice_pipe_desc spd = {
6822 .pages = pages_def,
6823 .partial = partial_def,
6824 .nr_pages = 0, /* This gets updated below. */
6825 .nr_pages_max = PIPE_DEF_BUFFERS,
6826 .ops = &default_pipe_buf_ops,
6827 .spd_release = tracing_spd_release_pipe,
6828 };
6829 ssize_t ret;
6830 size_t rem;
6831 unsigned int i;
6832
6833 if (splice_grow_spd(pipe, &spd))
6834 return -ENOMEM;
6835
6836 mutex_lock(&iter->mutex);
6837
6838 if (iter->trace->splice_read) {
6839 ret = iter->trace->splice_read(iter, filp,
6840 ppos, pipe, len, flags);
6841 if (ret)
6842 goto out_err;
6843 }
6844
6845 ret = tracing_wait_pipe(filp);
6846 if (ret <= 0)
6847 goto out_err;
6848
6849 if (!iter->ent && !trace_find_next_entry_inc(iter)) {
6850 ret = -EFAULT;
6851 goto out_err;
6852 }
6853
6854 trace_event_read_lock();
6855 trace_access_lock(iter->cpu_file);
6856
6857 /* Fill as many pages as possible. */
6858 for (i = 0, rem = len; i < spd.nr_pages_max && rem; i++) {
6859 spd.pages[i] = alloc_page(GFP_KERNEL);
6860 if (!spd.pages[i])
6861 break;
6862
6863 rem = tracing_fill_pipe_page(rem, iter);
6864
6865 /* Copy the data into the page, so we can start over. */
6866 ret = trace_seq_to_buffer(&iter->seq,
6867 page_address(spd.pages[i]),
6868 trace_seq_used(&iter->seq));
6869 if (ret < 0) {
6870 __free_page(spd.pages[i]);
6871 break;
6872 }
6873 spd.partial[i].offset = 0;
6874 spd.partial[i].len = trace_seq_used(&iter->seq);
6875
6876 trace_seq_init(&iter->seq);
6877 }
6878
6879 trace_access_unlock(iter->cpu_file);
6880 trace_event_read_unlock();
6881 mutex_unlock(&iter->mutex);
6882
6883 spd.nr_pages = i;
6884
6885 if (i)
6886 ret = splice_to_pipe(pipe, &spd);
6887 else
6888 ret = 0;
6889out:
6890 splice_shrink_spd(&spd);
6891 return ret;
6892
6893out_err:
6894 mutex_unlock(&iter->mutex);
6895 goto out;
6896}
6897
6898static ssize_t
6899tracing_entries_read(struct file *filp, char __user *ubuf,
6900 size_t cnt, loff_t *ppos)
6901{
6902 struct inode *inode = file_inode(filp);
6903 struct trace_array *tr = inode->i_private;
6904 int cpu = tracing_get_cpu(inode);
6905 char buf[64];
6906 int r = 0;
6907 ssize_t ret;
6908
6909 mutex_lock(&trace_types_lock);
6910
6911 if (cpu == RING_BUFFER_ALL_CPUS) {
6912 int cpu, buf_size_same;
6913 unsigned long size;
6914
6915 size = 0;
6916 buf_size_same = 1;
6917 /* check if all cpu sizes are same */
6918 for_each_tracing_cpu(cpu) {
6919 /* fill in the size from first enabled cpu */
6920 if (size == 0)
6921 size = per_cpu_ptr(tr->array_buffer.data, cpu)->entries;
6922 if (size != per_cpu_ptr(tr->array_buffer.data, cpu)->entries) {
6923 buf_size_same = 0;
6924 break;
6925 }
6926 }
6927
6928 if (buf_size_same) {
6929 if (!ring_buffer_expanded)
6930 r = sprintf(buf, "%lu (expanded: %lu)\n",
6931 size >> 10,
6932 trace_buf_size >> 10);
6933 else
6934 r = sprintf(buf, "%lu\n", size >> 10);
6935 } else
6936 r = sprintf(buf, "X\n");
6937 } else
6938 r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->array_buffer.data, cpu)->entries >> 10);
6939
6940 mutex_unlock(&trace_types_lock);
6941
6942 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6943 return ret;
6944}
6945
6946static ssize_t
6947tracing_entries_write(struct file *filp, const char __user *ubuf,
6948 size_t cnt, loff_t *ppos)
6949{
6950 struct inode *inode = file_inode(filp);
6951 struct trace_array *tr = inode->i_private;
6952 unsigned long val;
6953 int ret;
6954
6955 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6956 if (ret)
6957 return ret;
6958
6959 /* must have at least 1 entry */
6960 if (!val)
6961 return -EINVAL;
6962
6963 /* value is in KB */
6964 val <<= 10;
6965 ret = tracing_resize_ring_buffer(tr, val, tracing_get_cpu(inode));
6966 if (ret < 0)
6967 return ret;
6968
6969 *ppos += cnt;
6970
6971 return cnt;
6972}
6973
6974static ssize_t
6975tracing_total_entries_read(struct file *filp, char __user *ubuf,
6976 size_t cnt, loff_t *ppos)
6977{
6978 struct trace_array *tr = filp->private_data;
6979 char buf[64];
6980 int r, cpu;
6981 unsigned long size = 0, expanded_size = 0;
6982
6983 mutex_lock(&trace_types_lock);
6984 for_each_tracing_cpu(cpu) {
6985 size += per_cpu_ptr(tr->array_buffer.data, cpu)->entries >> 10;
6986 if (!ring_buffer_expanded)
6987 expanded_size += trace_buf_size >> 10;
6988 }
6989 if (ring_buffer_expanded)
6990 r = sprintf(buf, "%lu\n", size);
6991 else
6992 r = sprintf(buf, "%lu (expanded: %lu)\n", size, expanded_size);
6993 mutex_unlock(&trace_types_lock);
6994
6995 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6996}
6997
6998static ssize_t
6999tracing_free_buffer_write(struct file *filp, const char __user *ubuf,
7000 size_t cnt, loff_t *ppos)
7001{
7002 /*
7003 * There is no need to read what the user has written, this function
7004 * is just to make sure that there is no error when "echo" is used
7005 */
7006
7007 *ppos += cnt;
7008
7009 return cnt;
7010}
7011
7012static int
7013tracing_free_buffer_release(struct inode *inode, struct file *filp)
7014{
7015 struct trace_array *tr = inode->i_private;
7016
7017 /* disable tracing ? */
7018 if (tr->trace_flags & TRACE_ITER_STOP_ON_FREE)
7019 tracer_tracing_off(tr);
7020 /* resize the ring buffer to 0 */
7021 tracing_resize_ring_buffer(tr, 0, RING_BUFFER_ALL_CPUS);
7022
7023 trace_array_put(tr);
7024
7025 return 0;
7026}
7027
7028static ssize_t
7029tracing_mark_write(struct file *filp, const char __user *ubuf,
7030 size_t cnt, loff_t *fpos)
7031{
7032 struct trace_array *tr = filp->private_data;
7033 struct ring_buffer_event *event;
7034 enum event_trigger_type tt = ETT_NONE;
7035 struct trace_buffer *buffer;
7036 struct print_entry *entry;
7037 ssize_t written;
7038 int size;
7039 int len;
7040
7041/* Used in tracing_mark_raw_write() as well */
7042#define FAULTED_STR "<faulted>"
7043#define FAULTED_SIZE (sizeof(FAULTED_STR) - 1) /* '\0' is already accounted for */
7044
7045 if (tracing_disabled)
7046 return -EINVAL;
7047
7048 if (!(tr->trace_flags & TRACE_ITER_MARKERS))
7049 return -EINVAL;
7050
7051 if (cnt > TRACE_BUF_SIZE)
7052 cnt = TRACE_BUF_SIZE;
7053
7054 BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
7055
7056 size = sizeof(*entry) + cnt + 2; /* add '\0' and possible '\n' */
7057
7058 /* If less than "<faulted>", then make sure we can still add that */
7059 if (cnt < FAULTED_SIZE)
7060 size += FAULTED_SIZE - cnt;
7061
7062 buffer = tr->array_buffer.buffer;
7063 event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
7064 tracing_gen_ctx());
7065 if (unlikely(!event))
7066 /* Ring buffer disabled, return as if not open for write */
7067 return -EBADF;
7068
7069 entry = ring_buffer_event_data(event);
7070 entry->ip = _THIS_IP_;
7071
7072 len = __copy_from_user_inatomic(&entry->buf, ubuf, cnt);
7073 if (len) {
7074 memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE);
7075 cnt = FAULTED_SIZE;
7076 written = -EFAULT;
7077 } else
7078 written = cnt;
7079
7080 if (tr->trace_marker_file && !list_empty(&tr->trace_marker_file->triggers)) {
7081 /* do not add \n before testing triggers, but add \0 */
7082 entry->buf[cnt] = '\0';
7083 tt = event_triggers_call(tr->trace_marker_file, buffer, entry, event);
7084 }
7085
7086 if (entry->buf[cnt - 1] != '\n') {
7087 entry->buf[cnt] = '\n';
7088 entry->buf[cnt + 1] = '\0';
7089 } else
7090 entry->buf[cnt] = '\0';
7091
7092 if (static_branch_unlikely(&trace_marker_exports_enabled))
7093 ftrace_exports(event, TRACE_EXPORT_MARKER);
7094 __buffer_unlock_commit(buffer, event);
7095
7096 if (tt)
7097 event_triggers_post_call(tr->trace_marker_file, tt);
7098
7099 if (written > 0)
7100 *fpos += written;
7101
7102 return written;
7103}
7104
7105/* Limit it for now to 3K (including tag) */
7106#define RAW_DATA_MAX_SIZE (1024*3)
7107
7108static ssize_t
7109tracing_mark_raw_write(struct file *filp, const char __user *ubuf,
7110 size_t cnt, loff_t *fpos)
7111{
7112 struct trace_array *tr = filp->private_data;
7113 struct ring_buffer_event *event;
7114 struct trace_buffer *buffer;
7115 struct raw_data_entry *entry;
7116 ssize_t written;
7117 int size;
7118 int len;
7119
7120#define FAULT_SIZE_ID (FAULTED_SIZE + sizeof(int))
7121
7122 if (tracing_disabled)
7123 return -EINVAL;
7124
7125 if (!(tr->trace_flags & TRACE_ITER_MARKERS))
7126 return -EINVAL;
7127
7128 /* The marker must at least have a tag id */
7129 if (cnt < sizeof(unsigned int) || cnt > RAW_DATA_MAX_SIZE)
7130 return -EINVAL;
7131
7132 if (cnt > TRACE_BUF_SIZE)
7133 cnt = TRACE_BUF_SIZE;
7134
7135 BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
7136
7137 size = sizeof(*entry) + cnt;
7138 if (cnt < FAULT_SIZE_ID)
7139 size += FAULT_SIZE_ID - cnt;
7140
7141 buffer = tr->array_buffer.buffer;
7142 event = __trace_buffer_lock_reserve(buffer, TRACE_RAW_DATA, size,
7143 tracing_gen_ctx());
7144 if (!event)
7145 /* Ring buffer disabled, return as if not open for write */
7146 return -EBADF;
7147
7148 entry = ring_buffer_event_data(event);
7149
7150 len = __copy_from_user_inatomic(&entry->id, ubuf, cnt);
7151 if (len) {
7152 entry->id = -1;
7153 memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE);
7154 written = -EFAULT;
7155 } else
7156 written = cnt;
7157
7158 __buffer_unlock_commit(buffer, event);
7159
7160 if (written > 0)
7161 *fpos += written;
7162
7163 return written;
7164}
7165
7166static int tracing_clock_show(struct seq_file *m, void *v)
7167{
7168 struct trace_array *tr = m->private;
7169 int i;
7170
7171 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++)
7172 seq_printf(m,
7173 "%s%s%s%s", i ? " " : "",
7174 i == tr->clock_id ? "[" : "", trace_clocks[i].name,
7175 i == tr->clock_id ? "]" : "");
7176 seq_putc(m, '\n');
7177
7178 return 0;
7179}
7180
7181int tracing_set_clock(struct trace_array *tr, const char *clockstr)
7182{
7183 int i;
7184
7185 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) {
7186 if (strcmp(trace_clocks[i].name, clockstr) == 0)
7187 break;
7188 }
7189 if (i == ARRAY_SIZE(trace_clocks))
7190 return -EINVAL;
7191
7192 mutex_lock(&trace_types_lock);
7193
7194 tr->clock_id = i;
7195
7196 ring_buffer_set_clock(tr->array_buffer.buffer, trace_clocks[i].func);
7197
7198 /*
7199 * New clock may not be consistent with the previous clock.
7200 * Reset the buffer so that it doesn't have incomparable timestamps.
7201 */
7202 tracing_reset_online_cpus(&tr->array_buffer);
7203
7204#ifdef CONFIG_TRACER_MAX_TRACE
7205 if (tr->max_buffer.buffer)
7206 ring_buffer_set_clock(tr->max_buffer.buffer, trace_clocks[i].func);
7207 tracing_reset_online_cpus(&tr->max_buffer);
7208#endif
7209
7210 mutex_unlock(&trace_types_lock);
7211
7212 return 0;
7213}
7214
7215static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf,
7216 size_t cnt, loff_t *fpos)
7217{
7218 struct seq_file *m = filp->private_data;
7219 struct trace_array *tr = m->private;
7220 char buf[64];
7221 const char *clockstr;
7222 int ret;
7223
7224 if (cnt >= sizeof(buf))
7225 return -EINVAL;
7226
7227 if (copy_from_user(buf, ubuf, cnt))
7228 return -EFAULT;
7229
7230 buf[cnt] = 0;
7231
7232 clockstr = strstrip(buf);
7233
7234 ret = tracing_set_clock(tr, clockstr);
7235 if (ret)
7236 return ret;
7237
7238 *fpos += cnt;
7239
7240 return cnt;
7241}
7242
7243static int tracing_clock_open(struct inode *inode, struct file *file)
7244{
7245 struct trace_array *tr = inode->i_private;
7246 int ret;
7247
7248 ret = tracing_check_open_get_tr(tr);
7249 if (ret)
7250 return ret;
7251
7252 ret = single_open(file, tracing_clock_show, inode->i_private);
7253 if (ret < 0)
7254 trace_array_put(tr);
7255
7256 return ret;
7257}
7258
7259static int tracing_time_stamp_mode_show(struct seq_file *m, void *v)
7260{
7261 struct trace_array *tr = m->private;
7262
7263 mutex_lock(&trace_types_lock);
7264
7265 if (ring_buffer_time_stamp_abs(tr->array_buffer.buffer))
7266 seq_puts(m, "delta [absolute]\n");
7267 else
7268 seq_puts(m, "[delta] absolute\n");
7269
7270 mutex_unlock(&trace_types_lock);
7271
7272 return 0;
7273}
7274
7275static int tracing_time_stamp_mode_open(struct inode *inode, struct file *file)
7276{
7277 struct trace_array *tr = inode->i_private;
7278 int ret;
7279
7280 ret = tracing_check_open_get_tr(tr);
7281 if (ret)
7282 return ret;
7283
7284 ret = single_open(file, tracing_time_stamp_mode_show, inode->i_private);
7285 if (ret < 0)
7286 trace_array_put(tr);
7287
7288 return ret;
7289}
7290
7291u64 tracing_event_time_stamp(struct trace_buffer *buffer, struct ring_buffer_event *rbe)
7292{
7293 if (rbe == this_cpu_read(trace_buffered_event))
7294 return ring_buffer_time_stamp(buffer);
7295
7296 return ring_buffer_event_time_stamp(buffer, rbe);
7297}
7298
7299/*
7300 * Set or disable using the per CPU trace_buffer_event when possible.
7301 */
7302int tracing_set_filter_buffering(struct trace_array *tr, bool set)
7303{
7304 int ret = 0;
7305
7306 mutex_lock(&trace_types_lock);
7307
7308 if (set && tr->no_filter_buffering_ref++)
7309 goto out;
7310
7311 if (!set) {
7312 if (WARN_ON_ONCE(!tr->no_filter_buffering_ref)) {
7313 ret = -EINVAL;
7314 goto out;
7315 }
7316
7317 --tr->no_filter_buffering_ref;
7318 }
7319 out:
7320 mutex_unlock(&trace_types_lock);
7321
7322 return ret;
7323}
7324
7325struct ftrace_buffer_info {
7326 struct trace_iterator iter;
7327 void *spare;
7328 unsigned int spare_cpu;
7329 unsigned int read;
7330};
7331
7332#ifdef CONFIG_TRACER_SNAPSHOT
7333static int tracing_snapshot_open(struct inode *inode, struct file *file)
7334{
7335 struct trace_array *tr = inode->i_private;
7336 struct trace_iterator *iter;
7337 struct seq_file *m;
7338 int ret;
7339
7340 ret = tracing_check_open_get_tr(tr);
7341 if (ret)
7342 return ret;
7343
7344 if (file->f_mode & FMODE_READ) {
7345 iter = __tracing_open(inode, file, true);
7346 if (IS_ERR(iter))
7347 ret = PTR_ERR(iter);
7348 } else {
7349 /* Writes still need the seq_file to hold the private data */
7350 ret = -ENOMEM;
7351 m = kzalloc(sizeof(*m), GFP_KERNEL);
7352 if (!m)
7353 goto out;
7354 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
7355 if (!iter) {
7356 kfree(m);
7357 goto out;
7358 }
7359 ret = 0;
7360
7361 iter->tr = tr;
7362 iter->array_buffer = &tr->max_buffer;
7363 iter->cpu_file = tracing_get_cpu(inode);
7364 m->private = iter;
7365 file->private_data = m;
7366 }
7367out:
7368 if (ret < 0)
7369 trace_array_put(tr);
7370
7371 return ret;
7372}
7373
7374static ssize_t
7375tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
7376 loff_t *ppos)
7377{
7378 struct seq_file *m = filp->private_data;
7379 struct trace_iterator *iter = m->private;
7380 struct trace_array *tr = iter->tr;
7381 unsigned long val;
7382 int ret;
7383
7384 ret = tracing_update_buffers();
7385 if (ret < 0)
7386 return ret;
7387
7388 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
7389 if (ret)
7390 return ret;
7391
7392 mutex_lock(&trace_types_lock);
7393
7394 if (tr->current_trace->use_max_tr) {
7395 ret = -EBUSY;
7396 goto out;
7397 }
7398
7399 arch_spin_lock(&tr->max_lock);
7400 if (tr->cond_snapshot)
7401 ret = -EBUSY;
7402 arch_spin_unlock(&tr->max_lock);
7403 if (ret)
7404 goto out;
7405
7406 switch (val) {
7407 case 0:
7408 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
7409 ret = -EINVAL;
7410 break;
7411 }
7412 if (tr->allocated_snapshot)
7413 free_snapshot(tr);
7414 break;
7415 case 1:
7416/* Only allow per-cpu swap if the ring buffer supports it */
7417#ifndef CONFIG_RING_BUFFER_ALLOW_SWAP
7418 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
7419 ret = -EINVAL;
7420 break;
7421 }
7422#endif
7423 if (tr->allocated_snapshot)
7424 ret = resize_buffer_duplicate_size(&tr->max_buffer,
7425 &tr->array_buffer, iter->cpu_file);
7426 else
7427 ret = tracing_alloc_snapshot_instance(tr);
7428 if (ret < 0)
7429 break;
7430 local_irq_disable();
7431 /* Now, we're going to swap */
7432 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
7433 update_max_tr(tr, current, smp_processor_id(), NULL);
7434 else
7435 update_max_tr_single(tr, current, iter->cpu_file);
7436 local_irq_enable();
7437 break;
7438 default:
7439 if (tr->allocated_snapshot) {
7440 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
7441 tracing_reset_online_cpus(&tr->max_buffer);
7442 else
7443 tracing_reset_cpu(&tr->max_buffer, iter->cpu_file);
7444 }
7445 break;
7446 }
7447
7448 if (ret >= 0) {
7449 *ppos += cnt;
7450 ret = cnt;
7451 }
7452out:
7453 mutex_unlock(&trace_types_lock);
7454 return ret;
7455}
7456
7457static int tracing_snapshot_release(struct inode *inode, struct file *file)
7458{
7459 struct seq_file *m = file->private_data;
7460 int ret;
7461
7462 ret = tracing_release(inode, file);
7463
7464 if (file->f_mode & FMODE_READ)
7465 return ret;
7466
7467 /* If write only, the seq_file is just a stub */
7468 if (m)
7469 kfree(m->private);
7470 kfree(m);
7471
7472 return 0;
7473}
7474
7475static int tracing_buffers_open(struct inode *inode, struct file *filp);
7476static ssize_t tracing_buffers_read(struct file *filp, char __user *ubuf,
7477 size_t count, loff_t *ppos);
7478static int tracing_buffers_release(struct inode *inode, struct file *file);
7479static ssize_t tracing_buffers_splice_read(struct file *file, loff_t *ppos,
7480 struct pipe_inode_info *pipe, size_t len, unsigned int flags);
7481
7482static int snapshot_raw_open(struct inode *inode, struct file *filp)
7483{
7484 struct ftrace_buffer_info *info;
7485 int ret;
7486
7487 /* The following checks for tracefs lockdown */
7488 ret = tracing_buffers_open(inode, filp);
7489 if (ret < 0)
7490 return ret;
7491
7492 info = filp->private_data;
7493
7494 if (info->iter.trace->use_max_tr) {
7495 tracing_buffers_release(inode, filp);
7496 return -EBUSY;
7497 }
7498
7499 info->iter.snapshot = true;
7500 info->iter.array_buffer = &info->iter.tr->max_buffer;
7501
7502 return ret;
7503}
7504
7505#endif /* CONFIG_TRACER_SNAPSHOT */
7506
7507
7508static const struct file_operations tracing_thresh_fops = {
7509 .open = tracing_open_generic,
7510 .read = tracing_thresh_read,
7511 .write = tracing_thresh_write,
7512 .llseek = generic_file_llseek,
7513};
7514
7515#if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)
7516static const struct file_operations tracing_max_lat_fops = {
7517 .open = tracing_open_generic,
7518 .read = tracing_max_lat_read,
7519 .write = tracing_max_lat_write,
7520 .llseek = generic_file_llseek,
7521};
7522#endif
7523
7524static const struct file_operations set_tracer_fops = {
7525 .open = tracing_open_generic,
7526 .read = tracing_set_trace_read,
7527 .write = tracing_set_trace_write,
7528 .llseek = generic_file_llseek,
7529};
7530
7531static const struct file_operations tracing_pipe_fops = {
7532 .open = tracing_open_pipe,
7533 .poll = tracing_poll_pipe,
7534 .read = tracing_read_pipe,
7535 .splice_read = tracing_splice_read_pipe,
7536 .release = tracing_release_pipe,
7537 .llseek = no_llseek,
7538};
7539
7540static const struct file_operations tracing_entries_fops = {
7541 .open = tracing_open_generic_tr,
7542 .read = tracing_entries_read,
7543 .write = tracing_entries_write,
7544 .llseek = generic_file_llseek,
7545 .release = tracing_release_generic_tr,
7546};
7547
7548static const struct file_operations tracing_total_entries_fops = {
7549 .open = tracing_open_generic_tr,
7550 .read = tracing_total_entries_read,
7551 .llseek = generic_file_llseek,
7552 .release = tracing_release_generic_tr,
7553};
7554
7555static const struct file_operations tracing_free_buffer_fops = {
7556 .open = tracing_open_generic_tr,
7557 .write = tracing_free_buffer_write,
7558 .release = tracing_free_buffer_release,
7559};
7560
7561static const struct file_operations tracing_mark_fops = {
7562 .open = tracing_open_generic_tr,
7563 .write = tracing_mark_write,
7564 .llseek = generic_file_llseek,
7565 .release = tracing_release_generic_tr,
7566};
7567
7568static const struct file_operations tracing_mark_raw_fops = {
7569 .open = tracing_open_generic_tr,
7570 .write = tracing_mark_raw_write,
7571 .llseek = generic_file_llseek,
7572 .release = tracing_release_generic_tr,
7573};
7574
7575static const struct file_operations trace_clock_fops = {
7576 .open = tracing_clock_open,
7577 .read = seq_read,
7578 .llseek = seq_lseek,
7579 .release = tracing_single_release_tr,
7580 .write = tracing_clock_write,
7581};
7582
7583static const struct file_operations trace_time_stamp_mode_fops = {
7584 .open = tracing_time_stamp_mode_open,
7585 .read = seq_read,
7586 .llseek = seq_lseek,
7587 .release = tracing_single_release_tr,
7588};
7589
7590#ifdef CONFIG_TRACER_SNAPSHOT
7591static const struct file_operations snapshot_fops = {
7592 .open = tracing_snapshot_open,
7593 .read = seq_read,
7594 .write = tracing_snapshot_write,
7595 .llseek = tracing_lseek,
7596 .release = tracing_snapshot_release,
7597};
7598
7599static const struct file_operations snapshot_raw_fops = {
7600 .open = snapshot_raw_open,
7601 .read = tracing_buffers_read,
7602 .release = tracing_buffers_release,
7603 .splice_read = tracing_buffers_splice_read,
7604 .llseek = no_llseek,
7605};
7606
7607#endif /* CONFIG_TRACER_SNAPSHOT */
7608
7609/*
7610 * trace_min_max_write - Write a u64 value to a trace_min_max_param struct
7611 * @filp: The active open file structure
7612 * @ubuf: The userspace provided buffer to read value into
7613 * @cnt: The maximum number of bytes to read
7614 * @ppos: The current "file" position
7615 *
7616 * This function implements the write interface for a struct trace_min_max_param.
7617 * The filp->private_data must point to a trace_min_max_param structure that
7618 * defines where to write the value, the min and the max acceptable values,
7619 * and a lock to protect the write.
7620 */
7621static ssize_t
7622trace_min_max_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos)
7623{
7624 struct trace_min_max_param *param = filp->private_data;
7625 u64 val;
7626 int err;
7627
7628 if (!param)
7629 return -EFAULT;
7630
7631 err = kstrtoull_from_user(ubuf, cnt, 10, &val);
7632 if (err)
7633 return err;
7634
7635 if (param->lock)
7636 mutex_lock(param->lock);
7637
7638 if (param->min && val < *param->min)
7639 err = -EINVAL;
7640
7641 if (param->max && val > *param->max)
7642 err = -EINVAL;
7643
7644 if (!err)
7645 *param->val = val;
7646
7647 if (param->lock)
7648 mutex_unlock(param->lock);
7649
7650 if (err)
7651 return err;
7652
7653 return cnt;
7654}
7655
7656/*
7657 * trace_min_max_read - Read a u64 value from a trace_min_max_param struct
7658 * @filp: The active open file structure
7659 * @ubuf: The userspace provided buffer to read value into
7660 * @cnt: The maximum number of bytes to read
7661 * @ppos: The current "file" position
7662 *
7663 * This function implements the read interface for a struct trace_min_max_param.
7664 * The filp->private_data must point to a trace_min_max_param struct with valid
7665 * data.
7666 */
7667static ssize_t
7668trace_min_max_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
7669{
7670 struct trace_min_max_param *param = filp->private_data;
7671 char buf[U64_STR_SIZE];
7672 int len;
7673 u64 val;
7674
7675 if (!param)
7676 return -EFAULT;
7677
7678 val = *param->val;
7679
7680 if (cnt > sizeof(buf))
7681 cnt = sizeof(buf);
7682
7683 len = snprintf(buf, sizeof(buf), "%llu\n", val);
7684
7685 return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
7686}
7687
7688const struct file_operations trace_min_max_fops = {
7689 .open = tracing_open_generic,
7690 .read = trace_min_max_read,
7691 .write = trace_min_max_write,
7692};
7693
7694#define TRACING_LOG_ERRS_MAX 8
7695#define TRACING_LOG_LOC_MAX 128
7696
7697#define CMD_PREFIX " Command: "
7698
7699struct err_info {
7700 const char **errs; /* ptr to loc-specific array of err strings */
7701 u8 type; /* index into errs -> specific err string */
7702 u8 pos; /* MAX_FILTER_STR_VAL = 256 */
7703 u64 ts;
7704};
7705
7706struct tracing_log_err {
7707 struct list_head list;
7708 struct err_info info;
7709 char loc[TRACING_LOG_LOC_MAX]; /* err location */
7710 char cmd[MAX_FILTER_STR_VAL]; /* what caused err */
7711};
7712
7713static DEFINE_MUTEX(tracing_err_log_lock);
7714
7715static struct tracing_log_err *get_tracing_log_err(struct trace_array *tr)
7716{
7717 struct tracing_log_err *err;
7718
7719 if (tr->n_err_log_entries < TRACING_LOG_ERRS_MAX) {
7720 err = kzalloc(sizeof(*err), GFP_KERNEL);
7721 if (!err)
7722 err = ERR_PTR(-ENOMEM);
7723 tr->n_err_log_entries++;
7724
7725 return err;
7726 }
7727
7728 err = list_first_entry(&tr->err_log, struct tracing_log_err, list);
7729 list_del(&err->list);
7730
7731 return err;
7732}
7733
7734/**
7735 * err_pos - find the position of a string within a command for error careting
7736 * @cmd: The tracing command that caused the error
7737 * @str: The string to position the caret at within @cmd
7738 *
7739 * Finds the position of the first occurrence of @str within @cmd. The
7740 * return value can be passed to tracing_log_err() for caret placement
7741 * within @cmd.
7742 *
7743 * Returns the index within @cmd of the first occurrence of @str or 0
7744 * if @str was not found.
7745 */
7746unsigned int err_pos(char *cmd, const char *str)
7747{
7748 char *found;
7749
7750 if (WARN_ON(!strlen(cmd)))
7751 return 0;
7752
7753 found = strstr(cmd, str);
7754 if (found)
7755 return found - cmd;
7756
7757 return 0;
7758}
7759
7760/**
7761 * tracing_log_err - write an error to the tracing error log
7762 * @tr: The associated trace array for the error (NULL for top level array)
7763 * @loc: A string describing where the error occurred
7764 * @cmd: The tracing command that caused the error
7765 * @errs: The array of loc-specific static error strings
7766 * @type: The index into errs[], which produces the specific static err string
7767 * @pos: The position the caret should be placed in the cmd
7768 *
7769 * Writes an error into tracing/error_log of the form:
7770 *
7771 * <loc>: error: <text>
7772 * Command: <cmd>
7773 * ^
7774 *
7775 * tracing/error_log is a small log file containing the last
7776 * TRACING_LOG_ERRS_MAX errors (8). Memory for errors isn't allocated
7777 * unless there has been a tracing error, and the error log can be
7778 * cleared and have its memory freed by writing the empty string in
7779 * truncation mode to it i.e. echo > tracing/error_log.
7780 *
7781 * NOTE: the @errs array along with the @type param are used to
7782 * produce a static error string - this string is not copied and saved
7783 * when the error is logged - only a pointer to it is saved. See
7784 * existing callers for examples of how static strings are typically
7785 * defined for use with tracing_log_err().
7786 */
7787void tracing_log_err(struct trace_array *tr,
7788 const char *loc, const char *cmd,
7789 const char **errs, u8 type, u8 pos)
7790{
7791 struct tracing_log_err *err;
7792
7793 if (!tr)
7794 tr = &global_trace;
7795
7796 mutex_lock(&tracing_err_log_lock);
7797 err = get_tracing_log_err(tr);
7798 if (PTR_ERR(err) == -ENOMEM) {
7799 mutex_unlock(&tracing_err_log_lock);
7800 return;
7801 }
7802
7803 snprintf(err->loc, TRACING_LOG_LOC_MAX, "%s: error: ", loc);
7804 snprintf(err->cmd, MAX_FILTER_STR_VAL,"\n" CMD_PREFIX "%s\n", cmd);
7805
7806 err->info.errs = errs;
7807 err->info.type = type;
7808 err->info.pos = pos;
7809 err->info.ts = local_clock();
7810
7811 list_add_tail(&err->list, &tr->err_log);
7812 mutex_unlock(&tracing_err_log_lock);
7813}
7814
7815static void clear_tracing_err_log(struct trace_array *tr)
7816{
7817 struct tracing_log_err *err, *next;
7818
7819 mutex_lock(&tracing_err_log_lock);
7820 list_for_each_entry_safe(err, next, &tr->err_log, list) {
7821 list_del(&err->list);
7822 kfree(err);
7823 }
7824
7825 tr->n_err_log_entries = 0;
7826 mutex_unlock(&tracing_err_log_lock);
7827}
7828
7829static void *tracing_err_log_seq_start(struct seq_file *m, loff_t *pos)
7830{
7831 struct trace_array *tr = m->private;
7832
7833 mutex_lock(&tracing_err_log_lock);
7834
7835 return seq_list_start(&tr->err_log, *pos);
7836}
7837
7838static void *tracing_err_log_seq_next(struct seq_file *m, void *v, loff_t *pos)
7839{
7840 struct trace_array *tr = m->private;
7841
7842 return seq_list_next(v, &tr->err_log, pos);
7843}
7844
7845static void tracing_err_log_seq_stop(struct seq_file *m, void *v)
7846{
7847 mutex_unlock(&tracing_err_log_lock);
7848}
7849
7850static void tracing_err_log_show_pos(struct seq_file *m, u8 pos)
7851{
7852 u8 i;
7853
7854 for (i = 0; i < sizeof(CMD_PREFIX) - 1; i++)
7855 seq_putc(m, ' ');
7856 for (i = 0; i < pos; i++)
7857 seq_putc(m, ' ');
7858 seq_puts(m, "^\n");
7859}
7860
7861static int tracing_err_log_seq_show(struct seq_file *m, void *v)
7862{
7863 struct tracing_log_err *err = v;
7864
7865 if (err) {
7866 const char *err_text = err->info.errs[err->info.type];
7867 u64 sec = err->info.ts;
7868 u32 nsec;
7869
7870 nsec = do_div(sec, NSEC_PER_SEC);
7871 seq_printf(m, "[%5llu.%06u] %s%s", sec, nsec / 1000,
7872 err->loc, err_text);
7873 seq_printf(m, "%s", err->cmd);
7874 tracing_err_log_show_pos(m, err->info.pos);
7875 }
7876
7877 return 0;
7878}
7879
7880static const struct seq_operations tracing_err_log_seq_ops = {
7881 .start = tracing_err_log_seq_start,
7882 .next = tracing_err_log_seq_next,
7883 .stop = tracing_err_log_seq_stop,
7884 .show = tracing_err_log_seq_show
7885};
7886
7887static int tracing_err_log_open(struct inode *inode, struct file *file)
7888{
7889 struct trace_array *tr = inode->i_private;
7890 int ret = 0;
7891
7892 ret = tracing_check_open_get_tr(tr);
7893 if (ret)
7894 return ret;
7895
7896 /* If this file was opened for write, then erase contents */
7897 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC))
7898 clear_tracing_err_log(tr);
7899
7900 if (file->f_mode & FMODE_READ) {
7901 ret = seq_open(file, &tracing_err_log_seq_ops);
7902 if (!ret) {
7903 struct seq_file *m = file->private_data;
7904 m->private = tr;
7905 } else {
7906 trace_array_put(tr);
7907 }
7908 }
7909 return ret;
7910}
7911
7912static ssize_t tracing_err_log_write(struct file *file,
7913 const char __user *buffer,
7914 size_t count, loff_t *ppos)
7915{
7916 return count;
7917}
7918
7919static int tracing_err_log_release(struct inode *inode, struct file *file)
7920{
7921 struct trace_array *tr = inode->i_private;
7922
7923 trace_array_put(tr);
7924
7925 if (file->f_mode & FMODE_READ)
7926 seq_release(inode, file);
7927
7928 return 0;
7929}
7930
7931static const struct file_operations tracing_err_log_fops = {
7932 .open = tracing_err_log_open,
7933 .write = tracing_err_log_write,
7934 .read = seq_read,
7935 .llseek = seq_lseek,
7936 .release = tracing_err_log_release,
7937};
7938
7939static int tracing_buffers_open(struct inode *inode, struct file *filp)
7940{
7941 struct trace_array *tr = inode->i_private;
7942 struct ftrace_buffer_info *info;
7943 int ret;
7944
7945 ret = tracing_check_open_get_tr(tr);
7946 if (ret)
7947 return ret;
7948
7949 info = kvzalloc(sizeof(*info), GFP_KERNEL);
7950 if (!info) {
7951 trace_array_put(tr);
7952 return -ENOMEM;
7953 }
7954
7955 mutex_lock(&trace_types_lock);
7956
7957 info->iter.tr = tr;
7958 info->iter.cpu_file = tracing_get_cpu(inode);
7959 info->iter.trace = tr->current_trace;
7960 info->iter.array_buffer = &tr->array_buffer;
7961 info->spare = NULL;
7962 /* Force reading ring buffer for first read */
7963 info->read = (unsigned int)-1;
7964
7965 filp->private_data = info;
7966
7967 tr->trace_ref++;
7968
7969 mutex_unlock(&trace_types_lock);
7970
7971 ret = nonseekable_open(inode, filp);
7972 if (ret < 0)
7973 trace_array_put(tr);
7974
7975 return ret;
7976}
7977
7978static __poll_t
7979tracing_buffers_poll(struct file *filp, poll_table *poll_table)
7980{
7981 struct ftrace_buffer_info *info = filp->private_data;
7982 struct trace_iterator *iter = &info->iter;
7983
7984 return trace_poll(iter, filp, poll_table);
7985}
7986
7987static ssize_t
7988tracing_buffers_read(struct file *filp, char __user *ubuf,
7989 size_t count, loff_t *ppos)
7990{
7991 struct ftrace_buffer_info *info = filp->private_data;
7992 struct trace_iterator *iter = &info->iter;
7993 ssize_t ret = 0;
7994 ssize_t size;
7995
7996 if (!count)
7997 return 0;
7998
7999#ifdef CONFIG_TRACER_MAX_TRACE
8000 if (iter->snapshot && iter->tr->current_trace->use_max_tr)
8001 return -EBUSY;
8002#endif
8003
8004 if (!info->spare) {
8005 info->spare = ring_buffer_alloc_read_page(iter->array_buffer->buffer,
8006 iter->cpu_file);
8007 if (IS_ERR(info->spare)) {
8008 ret = PTR_ERR(info->spare);
8009 info->spare = NULL;
8010 } else {
8011 info->spare_cpu = iter->cpu_file;
8012 }
8013 }
8014 if (!info->spare)
8015 return ret;
8016
8017 /* Do we have previous read data to read? */
8018 if (info->read < PAGE_SIZE)
8019 goto read;
8020
8021 again:
8022 trace_access_lock(iter->cpu_file);
8023 ret = ring_buffer_read_page(iter->array_buffer->buffer,
8024 &info->spare,
8025 count,
8026 iter->cpu_file, 0);
8027 trace_access_unlock(iter->cpu_file);
8028
8029 if (ret < 0) {
8030 if (trace_empty(iter)) {
8031 if ((filp->f_flags & O_NONBLOCK))
8032 return -EAGAIN;
8033
8034 ret = wait_on_pipe(iter, 0);
8035 if (ret)
8036 return ret;
8037
8038 goto again;
8039 }
8040 return 0;
8041 }
8042
8043 info->read = 0;
8044 read:
8045 size = PAGE_SIZE - info->read;
8046 if (size > count)
8047 size = count;
8048
8049 ret = copy_to_user(ubuf, info->spare + info->read, size);
8050 if (ret == size)
8051 return -EFAULT;
8052
8053 size -= ret;
8054
8055 *ppos += size;
8056 info->read += size;
8057
8058 return size;
8059}
8060
8061static int tracing_buffers_release(struct inode *inode, struct file *file)
8062{
8063 struct ftrace_buffer_info *info = file->private_data;
8064 struct trace_iterator *iter = &info->iter;
8065
8066 mutex_lock(&trace_types_lock);
8067
8068 iter->tr->trace_ref--;
8069
8070 __trace_array_put(iter->tr);
8071
8072 if (info->spare)
8073 ring_buffer_free_read_page(iter->array_buffer->buffer,
8074 info->spare_cpu, info->spare);
8075 kvfree(info);
8076
8077 mutex_unlock(&trace_types_lock);
8078
8079 return 0;
8080}
8081
8082struct buffer_ref {
8083 struct trace_buffer *buffer;
8084 void *page;
8085 int cpu;
8086 refcount_t refcount;
8087};
8088
8089static void buffer_ref_release(struct buffer_ref *ref)
8090{
8091 if (!refcount_dec_and_test(&ref->refcount))
8092 return;
8093 ring_buffer_free_read_page(ref->buffer, ref->cpu, ref->page);
8094 kfree(ref);
8095}
8096
8097static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
8098 struct pipe_buffer *buf)
8099{
8100 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
8101
8102 buffer_ref_release(ref);
8103 buf->private = 0;
8104}
8105
8106static bool buffer_pipe_buf_get(struct pipe_inode_info *pipe,
8107 struct pipe_buffer *buf)
8108{
8109 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
8110
8111 if (refcount_read(&ref->refcount) > INT_MAX/2)
8112 return false;
8113
8114 refcount_inc(&ref->refcount);
8115 return true;
8116}
8117
8118/* Pipe buffer operations for a buffer. */
8119static const struct pipe_buf_operations buffer_pipe_buf_ops = {
8120 .release = buffer_pipe_buf_release,
8121 .get = buffer_pipe_buf_get,
8122};
8123
8124/*
8125 * Callback from splice_to_pipe(), if we need to release some pages
8126 * at the end of the spd in case we error'ed out in filling the pipe.
8127 */
8128static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
8129{
8130 struct buffer_ref *ref =
8131 (struct buffer_ref *)spd->partial[i].private;
8132
8133 buffer_ref_release(ref);
8134 spd->partial[i].private = 0;
8135}
8136
8137static ssize_t
8138tracing_buffers_splice_read(struct file *file, loff_t *ppos,
8139 struct pipe_inode_info *pipe, size_t len,
8140 unsigned int flags)
8141{
8142 struct ftrace_buffer_info *info = file->private_data;
8143 struct trace_iterator *iter = &info->iter;
8144 struct partial_page partial_def[PIPE_DEF_BUFFERS];
8145 struct page *pages_def[PIPE_DEF_BUFFERS];
8146 struct splice_pipe_desc spd = {
8147 .pages = pages_def,
8148 .partial = partial_def,
8149 .nr_pages_max = PIPE_DEF_BUFFERS,
8150 .ops = &buffer_pipe_buf_ops,
8151 .spd_release = buffer_spd_release,
8152 };
8153 struct buffer_ref *ref;
8154 int entries, i;
8155 ssize_t ret = 0;
8156
8157#ifdef CONFIG_TRACER_MAX_TRACE
8158 if (iter->snapshot && iter->tr->current_trace->use_max_tr)
8159 return -EBUSY;
8160#endif
8161
8162 if (*ppos & (PAGE_SIZE - 1))
8163 return -EINVAL;
8164
8165 if (len & (PAGE_SIZE - 1)) {
8166 if (len < PAGE_SIZE)
8167 return -EINVAL;
8168 len &= PAGE_MASK;
8169 }
8170
8171 if (splice_grow_spd(pipe, &spd))
8172 return -ENOMEM;
8173
8174 again:
8175 trace_access_lock(iter->cpu_file);
8176 entries = ring_buffer_entries_cpu(iter->array_buffer->buffer, iter->cpu_file);
8177
8178 for (i = 0; i < spd.nr_pages_max && len && entries; i++, len -= PAGE_SIZE) {
8179 struct page *page;
8180 int r;
8181
8182 ref = kzalloc(sizeof(*ref), GFP_KERNEL);
8183 if (!ref) {
8184 ret = -ENOMEM;
8185 break;
8186 }
8187
8188 refcount_set(&ref->refcount, 1);
8189 ref->buffer = iter->array_buffer->buffer;
8190 ref->page = ring_buffer_alloc_read_page(ref->buffer, iter->cpu_file);
8191 if (IS_ERR(ref->page)) {
8192 ret = PTR_ERR(ref->page);
8193 ref->page = NULL;
8194 kfree(ref);
8195 break;
8196 }
8197 ref->cpu = iter->cpu_file;
8198
8199 r = ring_buffer_read_page(ref->buffer, &ref->page,
8200 len, iter->cpu_file, 1);
8201 if (r < 0) {
8202 ring_buffer_free_read_page(ref->buffer, ref->cpu,
8203 ref->page);
8204 kfree(ref);
8205 break;
8206 }
8207
8208 page = virt_to_page(ref->page);
8209
8210 spd.pages[i] = page;
8211 spd.partial[i].len = PAGE_SIZE;
8212 spd.partial[i].offset = 0;
8213 spd.partial[i].private = (unsigned long)ref;
8214 spd.nr_pages++;
8215 *ppos += PAGE_SIZE;
8216
8217 entries = ring_buffer_entries_cpu(iter->array_buffer->buffer, iter->cpu_file);
8218 }
8219
8220 trace_access_unlock(iter->cpu_file);
8221 spd.nr_pages = i;
8222
8223 /* did we read anything? */
8224 if (!spd.nr_pages) {
8225 if (ret)
8226 goto out;
8227
8228 ret = -EAGAIN;
8229 if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK))
8230 goto out;
8231
8232 ret = wait_on_pipe(iter, iter->tr->buffer_percent);
8233 if (ret)
8234 goto out;
8235
8236 goto again;
8237 }
8238
8239 ret = splice_to_pipe(pipe, &spd);
8240out:
8241 splice_shrink_spd(&spd);
8242
8243 return ret;
8244}
8245
8246static const struct file_operations tracing_buffers_fops = {
8247 .open = tracing_buffers_open,
8248 .read = tracing_buffers_read,
8249 .poll = tracing_buffers_poll,
8250 .release = tracing_buffers_release,
8251 .splice_read = tracing_buffers_splice_read,
8252 .llseek = no_llseek,
8253};
8254
8255static ssize_t
8256tracing_stats_read(struct file *filp, char __user *ubuf,
8257 size_t count, loff_t *ppos)
8258{
8259 struct inode *inode = file_inode(filp);
8260 struct trace_array *tr = inode->i_private;
8261 struct array_buffer *trace_buf = &tr->array_buffer;
8262 int cpu = tracing_get_cpu(inode);
8263 struct trace_seq *s;
8264 unsigned long cnt;
8265 unsigned long long t;
8266 unsigned long usec_rem;
8267
8268 s = kmalloc(sizeof(*s), GFP_KERNEL);
8269 if (!s)
8270 return -ENOMEM;
8271
8272 trace_seq_init(s);
8273
8274 cnt = ring_buffer_entries_cpu(trace_buf->buffer, cpu);
8275 trace_seq_printf(s, "entries: %ld\n", cnt);
8276
8277 cnt = ring_buffer_overrun_cpu(trace_buf->buffer, cpu);
8278 trace_seq_printf(s, "overrun: %ld\n", cnt);
8279
8280 cnt = ring_buffer_commit_overrun_cpu(trace_buf->buffer, cpu);
8281 trace_seq_printf(s, "commit overrun: %ld\n", cnt);
8282
8283 cnt = ring_buffer_bytes_cpu(trace_buf->buffer, cpu);
8284 trace_seq_printf(s, "bytes: %ld\n", cnt);
8285
8286 if (trace_clocks[tr->clock_id].in_ns) {
8287 /* local or global for trace_clock */
8288 t = ns2usecs(ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
8289 usec_rem = do_div(t, USEC_PER_SEC);
8290 trace_seq_printf(s, "oldest event ts: %5llu.%06lu\n",
8291 t, usec_rem);
8292
8293 t = ns2usecs(ring_buffer_time_stamp(trace_buf->buffer));
8294 usec_rem = do_div(t, USEC_PER_SEC);
8295 trace_seq_printf(s, "now ts: %5llu.%06lu\n", t, usec_rem);
8296 } else {
8297 /* counter or tsc mode for trace_clock */
8298 trace_seq_printf(s, "oldest event ts: %llu\n",
8299 ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
8300
8301 trace_seq_printf(s, "now ts: %llu\n",
8302 ring_buffer_time_stamp(trace_buf->buffer));
8303 }
8304
8305 cnt = ring_buffer_dropped_events_cpu(trace_buf->buffer, cpu);
8306 trace_seq_printf(s, "dropped events: %ld\n", cnt);
8307
8308 cnt = ring_buffer_read_events_cpu(trace_buf->buffer, cpu);
8309 trace_seq_printf(s, "read events: %ld\n", cnt);
8310
8311 count = simple_read_from_buffer(ubuf, count, ppos,
8312 s->buffer, trace_seq_used(s));
8313
8314 kfree(s);
8315
8316 return count;
8317}
8318
8319static const struct file_operations tracing_stats_fops = {
8320 .open = tracing_open_generic_tr,
8321 .read = tracing_stats_read,
8322 .llseek = generic_file_llseek,
8323 .release = tracing_release_generic_tr,
8324};
8325
8326#ifdef CONFIG_DYNAMIC_FTRACE
8327
8328static ssize_t
8329tracing_read_dyn_info(struct file *filp, char __user *ubuf,
8330 size_t cnt, loff_t *ppos)
8331{
8332 ssize_t ret;
8333 char *buf;
8334 int r;
8335
8336 /* 256 should be plenty to hold the amount needed */
8337 buf = kmalloc(256, GFP_KERNEL);
8338 if (!buf)
8339 return -ENOMEM;
8340
8341 r = scnprintf(buf, 256, "%ld pages:%ld groups: %ld\n",
8342 ftrace_update_tot_cnt,
8343 ftrace_number_of_pages,
8344 ftrace_number_of_groups);
8345
8346 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
8347 kfree(buf);
8348 return ret;
8349}
8350
8351static const struct file_operations tracing_dyn_info_fops = {
8352 .open = tracing_open_generic,
8353 .read = tracing_read_dyn_info,
8354 .llseek = generic_file_llseek,
8355};
8356#endif /* CONFIG_DYNAMIC_FTRACE */
8357
8358#if defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE)
8359static void
8360ftrace_snapshot(unsigned long ip, unsigned long parent_ip,
8361 struct trace_array *tr, struct ftrace_probe_ops *ops,
8362 void *data)
8363{
8364 tracing_snapshot_instance(tr);
8365}
8366
8367static void
8368ftrace_count_snapshot(unsigned long ip, unsigned long parent_ip,
8369 struct trace_array *tr, struct ftrace_probe_ops *ops,
8370 void *data)
8371{
8372 struct ftrace_func_mapper *mapper = data;
8373 long *count = NULL;
8374
8375 if (mapper)
8376 count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
8377
8378 if (count) {
8379
8380 if (*count <= 0)
8381 return;
8382
8383 (*count)--;
8384 }
8385
8386 tracing_snapshot_instance(tr);
8387}
8388
8389static int
8390ftrace_snapshot_print(struct seq_file *m, unsigned long ip,
8391 struct ftrace_probe_ops *ops, void *data)
8392{
8393 struct ftrace_func_mapper *mapper = data;
8394 long *count = NULL;
8395
8396 seq_printf(m, "%ps:", (void *)ip);
8397
8398 seq_puts(m, "snapshot");
8399
8400 if (mapper)
8401 count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
8402
8403 if (count)
8404 seq_printf(m, ":count=%ld\n", *count);
8405 else
8406 seq_puts(m, ":unlimited\n");
8407
8408 return 0;
8409}
8410
8411static int
8412ftrace_snapshot_init(struct ftrace_probe_ops *ops, struct trace_array *tr,
8413 unsigned long ip, void *init_data, void **data)
8414{
8415 struct ftrace_func_mapper *mapper = *data;
8416
8417 if (!mapper) {
8418 mapper = allocate_ftrace_func_mapper();
8419 if (!mapper)
8420 return -ENOMEM;
8421 *data = mapper;
8422 }
8423
8424 return ftrace_func_mapper_add_ip(mapper, ip, init_data);
8425}
8426
8427static void
8428ftrace_snapshot_free(struct ftrace_probe_ops *ops, struct trace_array *tr,
8429 unsigned long ip, void *data)
8430{
8431 struct ftrace_func_mapper *mapper = data;
8432
8433 if (!ip) {
8434 if (!mapper)
8435 return;
8436 free_ftrace_func_mapper(mapper, NULL);
8437 return;
8438 }
8439
8440 ftrace_func_mapper_remove_ip(mapper, ip);
8441}
8442
8443static struct ftrace_probe_ops snapshot_probe_ops = {
8444 .func = ftrace_snapshot,
8445 .print = ftrace_snapshot_print,
8446};
8447
8448static struct ftrace_probe_ops snapshot_count_probe_ops = {
8449 .func = ftrace_count_snapshot,
8450 .print = ftrace_snapshot_print,
8451 .init = ftrace_snapshot_init,
8452 .free = ftrace_snapshot_free,
8453};
8454
8455static int
8456ftrace_trace_snapshot_callback(struct trace_array *tr, struct ftrace_hash *hash,
8457 char *glob, char *cmd, char *param, int enable)
8458{
8459 struct ftrace_probe_ops *ops;
8460 void *count = (void *)-1;
8461 char *number;
8462 int ret;
8463
8464 if (!tr)
8465 return -ENODEV;
8466
8467 /* hash funcs only work with set_ftrace_filter */
8468 if (!enable)
8469 return -EINVAL;
8470
8471 ops = param ? &snapshot_count_probe_ops : &snapshot_probe_ops;
8472
8473 if (glob[0] == '!')
8474 return unregister_ftrace_function_probe_func(glob+1, tr, ops);
8475
8476 if (!param)
8477 goto out_reg;
8478
8479 number = strsep(¶m, ":");
8480
8481 if (!strlen(number))
8482 goto out_reg;
8483
8484 /*
8485 * We use the callback data field (which is a pointer)
8486 * as our counter.
8487 */
8488 ret = kstrtoul(number, 0, (unsigned long *)&count);
8489 if (ret)
8490 return ret;
8491
8492 out_reg:
8493 ret = tracing_alloc_snapshot_instance(tr);
8494 if (ret < 0)
8495 goto out;
8496
8497 ret = register_ftrace_function_probe(glob, tr, ops, count);
8498
8499 out:
8500 return ret < 0 ? ret : 0;
8501}
8502
8503static struct ftrace_func_command ftrace_snapshot_cmd = {
8504 .name = "snapshot",
8505 .func = ftrace_trace_snapshot_callback,
8506};
8507
8508static __init int register_snapshot_cmd(void)
8509{
8510 return register_ftrace_command(&ftrace_snapshot_cmd);
8511}
8512#else
8513static inline __init int register_snapshot_cmd(void) { return 0; }
8514#endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
8515
8516static struct dentry *tracing_get_dentry(struct trace_array *tr)
8517{
8518 if (WARN_ON(!tr->dir))
8519 return ERR_PTR(-ENODEV);
8520
8521 /* Top directory uses NULL as the parent */
8522 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
8523 return NULL;
8524
8525 /* All sub buffers have a descriptor */
8526 return tr->dir;
8527}
8528
8529static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu)
8530{
8531 struct dentry *d_tracer;
8532
8533 if (tr->percpu_dir)
8534 return tr->percpu_dir;
8535
8536 d_tracer = tracing_get_dentry(tr);
8537 if (IS_ERR(d_tracer))
8538 return NULL;
8539
8540 tr->percpu_dir = tracefs_create_dir("per_cpu", d_tracer);
8541
8542 MEM_FAIL(!tr->percpu_dir,
8543 "Could not create tracefs directory 'per_cpu/%d'\n", cpu);
8544
8545 return tr->percpu_dir;
8546}
8547
8548static struct dentry *
8549trace_create_cpu_file(const char *name, umode_t mode, struct dentry *parent,
8550 void *data, long cpu, const struct file_operations *fops)
8551{
8552 struct dentry *ret = trace_create_file(name, mode, parent, data, fops);
8553
8554 if (ret) /* See tracing_get_cpu() */
8555 d_inode(ret)->i_cdev = (void *)(cpu + 1);
8556 return ret;
8557}
8558
8559static void
8560tracing_init_tracefs_percpu(struct trace_array *tr, long cpu)
8561{
8562 struct dentry *d_percpu = tracing_dentry_percpu(tr, cpu);
8563 struct dentry *d_cpu;
8564 char cpu_dir[30]; /* 30 characters should be more than enough */
8565
8566 if (!d_percpu)
8567 return;
8568
8569 snprintf(cpu_dir, 30, "cpu%ld", cpu);
8570 d_cpu = tracefs_create_dir(cpu_dir, d_percpu);
8571 if (!d_cpu) {
8572 pr_warn("Could not create tracefs '%s' entry\n", cpu_dir);
8573 return;
8574 }
8575
8576 /* per cpu trace_pipe */
8577 trace_create_cpu_file("trace_pipe", 0444, d_cpu,
8578 tr, cpu, &tracing_pipe_fops);
8579
8580 /* per cpu trace */
8581 trace_create_cpu_file("trace", 0644, d_cpu,
8582 tr, cpu, &tracing_fops);
8583
8584 trace_create_cpu_file("trace_pipe_raw", 0444, d_cpu,
8585 tr, cpu, &tracing_buffers_fops);
8586
8587 trace_create_cpu_file("stats", 0444, d_cpu,
8588 tr, cpu, &tracing_stats_fops);
8589
8590 trace_create_cpu_file("buffer_size_kb", 0444, d_cpu,
8591 tr, cpu, &tracing_entries_fops);
8592
8593#ifdef CONFIG_TRACER_SNAPSHOT
8594 trace_create_cpu_file("snapshot", 0644, d_cpu,
8595 tr, cpu, &snapshot_fops);
8596
8597 trace_create_cpu_file("snapshot_raw", 0444, d_cpu,
8598 tr, cpu, &snapshot_raw_fops);
8599#endif
8600}
8601
8602#ifdef CONFIG_FTRACE_SELFTEST
8603/* Let selftest have access to static functions in this file */
8604#include "trace_selftest.c"
8605#endif
8606
8607static ssize_t
8608trace_options_read(struct file *filp, char __user *ubuf, size_t cnt,
8609 loff_t *ppos)
8610{
8611 struct trace_option_dentry *topt = filp->private_data;
8612 char *buf;
8613
8614 if (topt->flags->val & topt->opt->bit)
8615 buf = "1\n";
8616 else
8617 buf = "0\n";
8618
8619 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
8620}
8621
8622static ssize_t
8623trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt,
8624 loff_t *ppos)
8625{
8626 struct trace_option_dentry *topt = filp->private_data;
8627 unsigned long val;
8628 int ret;
8629
8630 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
8631 if (ret)
8632 return ret;
8633
8634 if (val != 0 && val != 1)
8635 return -EINVAL;
8636
8637 if (!!(topt->flags->val & topt->opt->bit) != val) {
8638 mutex_lock(&trace_types_lock);
8639 ret = __set_tracer_option(topt->tr, topt->flags,
8640 topt->opt, !val);
8641 mutex_unlock(&trace_types_lock);
8642 if (ret)
8643 return ret;
8644 }
8645
8646 *ppos += cnt;
8647
8648 return cnt;
8649}
8650
8651
8652static const struct file_operations trace_options_fops = {
8653 .open = tracing_open_generic,
8654 .read = trace_options_read,
8655 .write = trace_options_write,
8656 .llseek = generic_file_llseek,
8657};
8658
8659/*
8660 * In order to pass in both the trace_array descriptor as well as the index
8661 * to the flag that the trace option file represents, the trace_array
8662 * has a character array of trace_flags_index[], which holds the index
8663 * of the bit for the flag it represents. index[0] == 0, index[1] == 1, etc.
8664 * The address of this character array is passed to the flag option file
8665 * read/write callbacks.
8666 *
8667 * In order to extract both the index and the trace_array descriptor,
8668 * get_tr_index() uses the following algorithm.
8669 *
8670 * idx = *ptr;
8671 *
8672 * As the pointer itself contains the address of the index (remember
8673 * index[1] == 1).
8674 *
8675 * Then to get the trace_array descriptor, by subtracting that index
8676 * from the ptr, we get to the start of the index itself.
8677 *
8678 * ptr - idx == &index[0]
8679 *
8680 * Then a simple container_of() from that pointer gets us to the
8681 * trace_array descriptor.
8682 */
8683static void get_tr_index(void *data, struct trace_array **ptr,
8684 unsigned int *pindex)
8685{
8686 *pindex = *(unsigned char *)data;
8687
8688 *ptr = container_of(data - *pindex, struct trace_array,
8689 trace_flags_index);
8690}
8691
8692static ssize_t
8693trace_options_core_read(struct file *filp, char __user *ubuf, size_t cnt,
8694 loff_t *ppos)
8695{
8696 void *tr_index = filp->private_data;
8697 struct trace_array *tr;
8698 unsigned int index;
8699 char *buf;
8700
8701 get_tr_index(tr_index, &tr, &index);
8702
8703 if (tr->trace_flags & (1 << index))
8704 buf = "1\n";
8705 else
8706 buf = "0\n";
8707
8708 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
8709}
8710
8711static ssize_t
8712trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
8713 loff_t *ppos)
8714{
8715 void *tr_index = filp->private_data;
8716 struct trace_array *tr;
8717 unsigned int index;
8718 unsigned long val;
8719 int ret;
8720
8721 get_tr_index(tr_index, &tr, &index);
8722
8723 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
8724 if (ret)
8725 return ret;
8726
8727 if (val != 0 && val != 1)
8728 return -EINVAL;
8729
8730 mutex_lock(&event_mutex);
8731 mutex_lock(&trace_types_lock);
8732 ret = set_tracer_flag(tr, 1 << index, val);
8733 mutex_unlock(&trace_types_lock);
8734 mutex_unlock(&event_mutex);
8735
8736 if (ret < 0)
8737 return ret;
8738
8739 *ppos += cnt;
8740
8741 return cnt;
8742}
8743
8744static const struct file_operations trace_options_core_fops = {
8745 .open = tracing_open_generic,
8746 .read = trace_options_core_read,
8747 .write = trace_options_core_write,
8748 .llseek = generic_file_llseek,
8749};
8750
8751struct dentry *trace_create_file(const char *name,
8752 umode_t mode,
8753 struct dentry *parent,
8754 void *data,
8755 const struct file_operations *fops)
8756{
8757 struct dentry *ret;
8758
8759 ret = tracefs_create_file(name, mode, parent, data, fops);
8760 if (!ret)
8761 pr_warn("Could not create tracefs '%s' entry\n", name);
8762
8763 return ret;
8764}
8765
8766
8767static struct dentry *trace_options_init_dentry(struct trace_array *tr)
8768{
8769 struct dentry *d_tracer;
8770
8771 if (tr->options)
8772 return tr->options;
8773
8774 d_tracer = tracing_get_dentry(tr);
8775 if (IS_ERR(d_tracer))
8776 return NULL;
8777
8778 tr->options = tracefs_create_dir("options", d_tracer);
8779 if (!tr->options) {
8780 pr_warn("Could not create tracefs directory 'options'\n");
8781 return NULL;
8782 }
8783
8784 return tr->options;
8785}
8786
8787static void
8788create_trace_option_file(struct trace_array *tr,
8789 struct trace_option_dentry *topt,
8790 struct tracer_flags *flags,
8791 struct tracer_opt *opt)
8792{
8793 struct dentry *t_options;
8794
8795 t_options = trace_options_init_dentry(tr);
8796 if (!t_options)
8797 return;
8798
8799 topt->flags = flags;
8800 topt->opt = opt;
8801 topt->tr = tr;
8802
8803 topt->entry = trace_create_file(opt->name, 0644, t_options, topt,
8804 &trace_options_fops);
8805
8806}
8807
8808static void
8809create_trace_option_files(struct trace_array *tr, struct tracer *tracer)
8810{
8811 struct trace_option_dentry *topts;
8812 struct trace_options *tr_topts;
8813 struct tracer_flags *flags;
8814 struct tracer_opt *opts;
8815 int cnt;
8816 int i;
8817
8818 if (!tracer)
8819 return;
8820
8821 flags = tracer->flags;
8822
8823 if (!flags || !flags->opts)
8824 return;
8825
8826 /*
8827 * If this is an instance, only create flags for tracers
8828 * the instance may have.
8829 */
8830 if (!trace_ok_for_array(tracer, tr))
8831 return;
8832
8833 for (i = 0; i < tr->nr_topts; i++) {
8834 /* Make sure there's no duplicate flags. */
8835 if (WARN_ON_ONCE(tr->topts[i].tracer->flags == tracer->flags))
8836 return;
8837 }
8838
8839 opts = flags->opts;
8840
8841 for (cnt = 0; opts[cnt].name; cnt++)
8842 ;
8843
8844 topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL);
8845 if (!topts)
8846 return;
8847
8848 tr_topts = krealloc(tr->topts, sizeof(*tr->topts) * (tr->nr_topts + 1),
8849 GFP_KERNEL);
8850 if (!tr_topts) {
8851 kfree(topts);
8852 return;
8853 }
8854
8855 tr->topts = tr_topts;
8856 tr->topts[tr->nr_topts].tracer = tracer;
8857 tr->topts[tr->nr_topts].topts = topts;
8858 tr->nr_topts++;
8859
8860 for (cnt = 0; opts[cnt].name; cnt++) {
8861 create_trace_option_file(tr, &topts[cnt], flags,
8862 &opts[cnt]);
8863 MEM_FAIL(topts[cnt].entry == NULL,
8864 "Failed to create trace option: %s",
8865 opts[cnt].name);
8866 }
8867}
8868
8869static struct dentry *
8870create_trace_option_core_file(struct trace_array *tr,
8871 const char *option, long index)
8872{
8873 struct dentry *t_options;
8874
8875 t_options = trace_options_init_dentry(tr);
8876 if (!t_options)
8877 return NULL;
8878
8879 return trace_create_file(option, 0644, t_options,
8880 (void *)&tr->trace_flags_index[index],
8881 &trace_options_core_fops);
8882}
8883
8884static void create_trace_options_dir(struct trace_array *tr)
8885{
8886 struct dentry *t_options;
8887 bool top_level = tr == &global_trace;
8888 int i;
8889
8890 t_options = trace_options_init_dentry(tr);
8891 if (!t_options)
8892 return;
8893
8894 for (i = 0; trace_options[i]; i++) {
8895 if (top_level ||
8896 !((1 << i) & TOP_LEVEL_TRACE_FLAGS))
8897 create_trace_option_core_file(tr, trace_options[i], i);
8898 }
8899}
8900
8901static ssize_t
8902rb_simple_read(struct file *filp, char __user *ubuf,
8903 size_t cnt, loff_t *ppos)
8904{
8905 struct trace_array *tr = filp->private_data;
8906 char buf[64];
8907 int r;
8908
8909 r = tracer_tracing_is_on(tr);
8910 r = sprintf(buf, "%d\n", r);
8911
8912 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
8913}
8914
8915static ssize_t
8916rb_simple_write(struct file *filp, const char __user *ubuf,
8917 size_t cnt, loff_t *ppos)
8918{
8919 struct trace_array *tr = filp->private_data;
8920 struct trace_buffer *buffer = tr->array_buffer.buffer;
8921 unsigned long val;
8922 int ret;
8923
8924 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
8925 if (ret)
8926 return ret;
8927
8928 if (buffer) {
8929 mutex_lock(&trace_types_lock);
8930 if (!!val == tracer_tracing_is_on(tr)) {
8931 val = 0; /* do nothing */
8932 } else if (val) {
8933 tracer_tracing_on(tr);
8934 if (tr->current_trace->start)
8935 tr->current_trace->start(tr);
8936 } else {
8937 tracer_tracing_off(tr);
8938 if (tr->current_trace->stop)
8939 tr->current_trace->stop(tr);
8940 }
8941 mutex_unlock(&trace_types_lock);
8942 }
8943
8944 (*ppos)++;
8945
8946 return cnt;
8947}
8948
8949static const struct file_operations rb_simple_fops = {
8950 .open = tracing_open_generic_tr,
8951 .read = rb_simple_read,
8952 .write = rb_simple_write,
8953 .release = tracing_release_generic_tr,
8954 .llseek = default_llseek,
8955};
8956
8957static ssize_t
8958buffer_percent_read(struct file *filp, char __user *ubuf,
8959 size_t cnt, loff_t *ppos)
8960{
8961 struct trace_array *tr = filp->private_data;
8962 char buf[64];
8963 int r;
8964
8965 r = tr->buffer_percent;
8966 r = sprintf(buf, "%d\n", r);
8967
8968 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
8969}
8970
8971static ssize_t
8972buffer_percent_write(struct file *filp, const char __user *ubuf,
8973 size_t cnt, loff_t *ppos)
8974{
8975 struct trace_array *tr = filp->private_data;
8976 unsigned long val;
8977 int ret;
8978
8979 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
8980 if (ret)
8981 return ret;
8982
8983 if (val > 100)
8984 return -EINVAL;
8985
8986 if (!val)
8987 val = 1;
8988
8989 tr->buffer_percent = val;
8990
8991 (*ppos)++;
8992
8993 return cnt;
8994}
8995
8996static const struct file_operations buffer_percent_fops = {
8997 .open = tracing_open_generic_tr,
8998 .read = buffer_percent_read,
8999 .write = buffer_percent_write,
9000 .release = tracing_release_generic_tr,
9001 .llseek = default_llseek,
9002};
9003
9004static struct dentry *trace_instance_dir;
9005
9006static void
9007init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer);
9008
9009static int
9010allocate_trace_buffer(struct trace_array *tr, struct array_buffer *buf, int size)
9011{
9012 enum ring_buffer_flags rb_flags;
9013
9014 rb_flags = tr->trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0;
9015
9016 buf->tr = tr;
9017
9018 buf->buffer = ring_buffer_alloc(size, rb_flags);
9019 if (!buf->buffer)
9020 return -ENOMEM;
9021
9022 buf->data = alloc_percpu(struct trace_array_cpu);
9023 if (!buf->data) {
9024 ring_buffer_free(buf->buffer);
9025 buf->buffer = NULL;
9026 return -ENOMEM;
9027 }
9028
9029 /* Allocate the first page for all buffers */
9030 set_buffer_entries(&tr->array_buffer,
9031 ring_buffer_size(tr->array_buffer.buffer, 0));
9032
9033 return 0;
9034}
9035
9036static int allocate_trace_buffers(struct trace_array *tr, int size)
9037{
9038 int ret;
9039
9040 ret = allocate_trace_buffer(tr, &tr->array_buffer, size);
9041 if (ret)
9042 return ret;
9043
9044#ifdef CONFIG_TRACER_MAX_TRACE
9045 ret = allocate_trace_buffer(tr, &tr->max_buffer,
9046 allocate_snapshot ? size : 1);
9047 if (MEM_FAIL(ret, "Failed to allocate trace buffer\n")) {
9048 ring_buffer_free(tr->array_buffer.buffer);
9049 tr->array_buffer.buffer = NULL;
9050 free_percpu(tr->array_buffer.data);
9051 tr->array_buffer.data = NULL;
9052 return -ENOMEM;
9053 }
9054 tr->allocated_snapshot = allocate_snapshot;
9055
9056 /*
9057 * Only the top level trace array gets its snapshot allocated
9058 * from the kernel command line.
9059 */
9060 allocate_snapshot = false;
9061#endif
9062
9063 return 0;
9064}
9065
9066static void free_trace_buffer(struct array_buffer *buf)
9067{
9068 if (buf->buffer) {
9069 ring_buffer_free(buf->buffer);
9070 buf->buffer = NULL;
9071 free_percpu(buf->data);
9072 buf->data = NULL;
9073 }
9074}
9075
9076static void free_trace_buffers(struct trace_array *tr)
9077{
9078 if (!tr)
9079 return;
9080
9081 free_trace_buffer(&tr->array_buffer);
9082
9083#ifdef CONFIG_TRACER_MAX_TRACE
9084 free_trace_buffer(&tr->max_buffer);
9085#endif
9086}
9087
9088static void init_trace_flags_index(struct trace_array *tr)
9089{
9090 int i;
9091
9092 /* Used by the trace options files */
9093 for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++)
9094 tr->trace_flags_index[i] = i;
9095}
9096
9097static void __update_tracer_options(struct trace_array *tr)
9098{
9099 struct tracer *t;
9100
9101 for (t = trace_types; t; t = t->next)
9102 add_tracer_options(tr, t);
9103}
9104
9105static void update_tracer_options(struct trace_array *tr)
9106{
9107 mutex_lock(&trace_types_lock);
9108 __update_tracer_options(tr);
9109 mutex_unlock(&trace_types_lock);
9110}
9111
9112/* Must have trace_types_lock held */
9113struct trace_array *trace_array_find(const char *instance)
9114{
9115 struct trace_array *tr, *found = NULL;
9116
9117 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9118 if (tr->name && strcmp(tr->name, instance) == 0) {
9119 found = tr;
9120 break;
9121 }
9122 }
9123
9124 return found;
9125}
9126
9127struct trace_array *trace_array_find_get(const char *instance)
9128{
9129 struct trace_array *tr;
9130
9131 mutex_lock(&trace_types_lock);
9132 tr = trace_array_find(instance);
9133 if (tr)
9134 tr->ref++;
9135 mutex_unlock(&trace_types_lock);
9136
9137 return tr;
9138}
9139
9140static int trace_array_create_dir(struct trace_array *tr)
9141{
9142 int ret;
9143
9144 tr->dir = tracefs_create_dir(tr->name, trace_instance_dir);
9145 if (!tr->dir)
9146 return -EINVAL;
9147
9148 ret = event_trace_add_tracer(tr->dir, tr);
9149 if (ret) {
9150 tracefs_remove(tr->dir);
9151 return ret;
9152 }
9153
9154 init_tracer_tracefs(tr, tr->dir);
9155 __update_tracer_options(tr);
9156
9157 return ret;
9158}
9159
9160static struct trace_array *trace_array_create(const char *name)
9161{
9162 struct trace_array *tr;
9163 int ret;
9164
9165 ret = -ENOMEM;
9166 tr = kzalloc(sizeof(*tr), GFP_KERNEL);
9167 if (!tr)
9168 return ERR_PTR(ret);
9169
9170 tr->name = kstrdup(name, GFP_KERNEL);
9171 if (!tr->name)
9172 goto out_free_tr;
9173
9174 if (!alloc_cpumask_var(&tr->tracing_cpumask, GFP_KERNEL))
9175 goto out_free_tr;
9176
9177 tr->trace_flags = global_trace.trace_flags & ~ZEROED_TRACE_FLAGS;
9178
9179 cpumask_copy(tr->tracing_cpumask, cpu_all_mask);
9180
9181 raw_spin_lock_init(&tr->start_lock);
9182
9183 tr->max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
9184
9185 tr->current_trace = &nop_trace;
9186
9187 INIT_LIST_HEAD(&tr->systems);
9188 INIT_LIST_HEAD(&tr->events);
9189 INIT_LIST_HEAD(&tr->hist_vars);
9190 INIT_LIST_HEAD(&tr->err_log);
9191
9192 if (allocate_trace_buffers(tr, trace_buf_size) < 0)
9193 goto out_free_tr;
9194
9195 if (ftrace_allocate_ftrace_ops(tr) < 0)
9196 goto out_free_tr;
9197
9198 ftrace_init_trace_array(tr);
9199
9200 init_trace_flags_index(tr);
9201
9202 if (trace_instance_dir) {
9203 ret = trace_array_create_dir(tr);
9204 if (ret)
9205 goto out_free_tr;
9206 } else
9207 __trace_early_add_events(tr);
9208
9209 list_add(&tr->list, &ftrace_trace_arrays);
9210
9211 tr->ref++;
9212
9213 return tr;
9214
9215 out_free_tr:
9216 ftrace_free_ftrace_ops(tr);
9217 free_trace_buffers(tr);
9218 free_cpumask_var(tr->tracing_cpumask);
9219 kfree(tr->name);
9220 kfree(tr);
9221
9222 return ERR_PTR(ret);
9223}
9224
9225static int instance_mkdir(const char *name)
9226{
9227 struct trace_array *tr;
9228 int ret;
9229
9230 mutex_lock(&event_mutex);
9231 mutex_lock(&trace_types_lock);
9232
9233 ret = -EEXIST;
9234 if (trace_array_find(name))
9235 goto out_unlock;
9236
9237 tr = trace_array_create(name);
9238
9239 ret = PTR_ERR_OR_ZERO(tr);
9240
9241out_unlock:
9242 mutex_unlock(&trace_types_lock);
9243 mutex_unlock(&event_mutex);
9244 return ret;
9245}
9246
9247/**
9248 * trace_array_get_by_name - Create/Lookup a trace array, given its name.
9249 * @name: The name of the trace array to be looked up/created.
9250 *
9251 * Returns pointer to trace array with given name.
9252 * NULL, if it cannot be created.
9253 *
9254 * NOTE: This function increments the reference counter associated with the
9255 * trace array returned. This makes sure it cannot be freed while in use.
9256 * Use trace_array_put() once the trace array is no longer needed.
9257 * If the trace_array is to be freed, trace_array_destroy() needs to
9258 * be called after the trace_array_put(), or simply let user space delete
9259 * it from the tracefs instances directory. But until the
9260 * trace_array_put() is called, user space can not delete it.
9261 *
9262 */
9263struct trace_array *trace_array_get_by_name(const char *name)
9264{
9265 struct trace_array *tr;
9266
9267 mutex_lock(&event_mutex);
9268 mutex_lock(&trace_types_lock);
9269
9270 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9271 if (tr->name && strcmp(tr->name, name) == 0)
9272 goto out_unlock;
9273 }
9274
9275 tr = trace_array_create(name);
9276
9277 if (IS_ERR(tr))
9278 tr = NULL;
9279out_unlock:
9280 if (tr)
9281 tr->ref++;
9282
9283 mutex_unlock(&trace_types_lock);
9284 mutex_unlock(&event_mutex);
9285 return tr;
9286}
9287EXPORT_SYMBOL_GPL(trace_array_get_by_name);
9288
9289static int __remove_instance(struct trace_array *tr)
9290{
9291 int i;
9292
9293 /* Reference counter for a newly created trace array = 1. */
9294 if (tr->ref > 1 || (tr->current_trace && tr->trace_ref))
9295 return -EBUSY;
9296
9297 list_del(&tr->list);
9298
9299 /* Disable all the flags that were enabled coming in */
9300 for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++) {
9301 if ((1 << i) & ZEROED_TRACE_FLAGS)
9302 set_tracer_flag(tr, 1 << i, 0);
9303 }
9304
9305 tracing_set_nop(tr);
9306 clear_ftrace_function_probes(tr);
9307 event_trace_del_tracer(tr);
9308 ftrace_clear_pids(tr);
9309 ftrace_destroy_function_files(tr);
9310 tracefs_remove(tr->dir);
9311 free_percpu(tr->last_func_repeats);
9312 free_trace_buffers(tr);
9313
9314 for (i = 0; i < tr->nr_topts; i++) {
9315 kfree(tr->topts[i].topts);
9316 }
9317 kfree(tr->topts);
9318
9319 free_cpumask_var(tr->tracing_cpumask);
9320 kfree(tr->name);
9321 kfree(tr);
9322
9323 return 0;
9324}
9325
9326int trace_array_destroy(struct trace_array *this_tr)
9327{
9328 struct trace_array *tr;
9329 int ret;
9330
9331 if (!this_tr)
9332 return -EINVAL;
9333
9334 mutex_lock(&event_mutex);
9335 mutex_lock(&trace_types_lock);
9336
9337 ret = -ENODEV;
9338
9339 /* Making sure trace array exists before destroying it. */
9340 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9341 if (tr == this_tr) {
9342 ret = __remove_instance(tr);
9343 break;
9344 }
9345 }
9346
9347 mutex_unlock(&trace_types_lock);
9348 mutex_unlock(&event_mutex);
9349
9350 return ret;
9351}
9352EXPORT_SYMBOL_GPL(trace_array_destroy);
9353
9354static int instance_rmdir(const char *name)
9355{
9356 struct trace_array *tr;
9357 int ret;
9358
9359 mutex_lock(&event_mutex);
9360 mutex_lock(&trace_types_lock);
9361
9362 ret = -ENODEV;
9363 tr = trace_array_find(name);
9364 if (tr)
9365 ret = __remove_instance(tr);
9366
9367 mutex_unlock(&trace_types_lock);
9368 mutex_unlock(&event_mutex);
9369
9370 return ret;
9371}
9372
9373static __init void create_trace_instances(struct dentry *d_tracer)
9374{
9375 struct trace_array *tr;
9376
9377 trace_instance_dir = tracefs_create_instance_dir("instances", d_tracer,
9378 instance_mkdir,
9379 instance_rmdir);
9380 if (MEM_FAIL(!trace_instance_dir, "Failed to create instances directory\n"))
9381 return;
9382
9383 mutex_lock(&event_mutex);
9384 mutex_lock(&trace_types_lock);
9385
9386 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9387 if (!tr->name)
9388 continue;
9389 if (MEM_FAIL(trace_array_create_dir(tr) < 0,
9390 "Failed to create instance directory\n"))
9391 break;
9392 }
9393
9394 mutex_unlock(&trace_types_lock);
9395 mutex_unlock(&event_mutex);
9396}
9397
9398static void
9399init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
9400{
9401 struct trace_event_file *file;
9402 int cpu;
9403
9404 trace_create_file("available_tracers", 0444, d_tracer,
9405 tr, &show_traces_fops);
9406
9407 trace_create_file("current_tracer", 0644, d_tracer,
9408 tr, &set_tracer_fops);
9409
9410 trace_create_file("tracing_cpumask", 0644, d_tracer,
9411 tr, &tracing_cpumask_fops);
9412
9413 trace_create_file("trace_options", 0644, d_tracer,
9414 tr, &tracing_iter_fops);
9415
9416 trace_create_file("trace", 0644, d_tracer,
9417 tr, &tracing_fops);
9418
9419 trace_create_file("trace_pipe", 0444, d_tracer,
9420 tr, &tracing_pipe_fops);
9421
9422 trace_create_file("buffer_size_kb", 0644, d_tracer,
9423 tr, &tracing_entries_fops);
9424
9425 trace_create_file("buffer_total_size_kb", 0444, d_tracer,
9426 tr, &tracing_total_entries_fops);
9427
9428 trace_create_file("free_buffer", 0200, d_tracer,
9429 tr, &tracing_free_buffer_fops);
9430
9431 trace_create_file("trace_marker", 0220, d_tracer,
9432 tr, &tracing_mark_fops);
9433
9434 file = __find_event_file(tr, "ftrace", "print");
9435 if (file && file->dir)
9436 trace_create_file("trigger", 0644, file->dir, file,
9437 &event_trigger_fops);
9438 tr->trace_marker_file = file;
9439
9440 trace_create_file("trace_marker_raw", 0220, d_tracer,
9441 tr, &tracing_mark_raw_fops);
9442
9443 trace_create_file("trace_clock", 0644, d_tracer, tr,
9444 &trace_clock_fops);
9445
9446 trace_create_file("tracing_on", 0644, d_tracer,
9447 tr, &rb_simple_fops);
9448
9449 trace_create_file("timestamp_mode", 0444, d_tracer, tr,
9450 &trace_time_stamp_mode_fops);
9451
9452 tr->buffer_percent = 50;
9453
9454 trace_create_file("buffer_percent", 0444, d_tracer,
9455 tr, &buffer_percent_fops);
9456
9457 create_trace_options_dir(tr);
9458
9459 trace_create_maxlat_file(tr, d_tracer);
9460
9461 if (ftrace_create_function_files(tr, d_tracer))
9462 MEM_FAIL(1, "Could not allocate function filter files");
9463
9464#ifdef CONFIG_TRACER_SNAPSHOT
9465 trace_create_file("snapshot", 0644, d_tracer,
9466 tr, &snapshot_fops);
9467#endif
9468
9469 trace_create_file("error_log", 0644, d_tracer,
9470 tr, &tracing_err_log_fops);
9471
9472 for_each_tracing_cpu(cpu)
9473 tracing_init_tracefs_percpu(tr, cpu);
9474
9475 ftrace_init_tracefs(tr, d_tracer);
9476}
9477
9478static struct vfsmount *trace_automount(struct dentry *mntpt, void *ingore)
9479{
9480 struct vfsmount *mnt;
9481 struct file_system_type *type;
9482
9483 /*
9484 * To maintain backward compatibility for tools that mount
9485 * debugfs to get to the tracing facility, tracefs is automatically
9486 * mounted to the debugfs/tracing directory.
9487 */
9488 type = get_fs_type("tracefs");
9489 if (!type)
9490 return NULL;
9491 mnt = vfs_submount(mntpt, type, "tracefs", NULL);
9492 put_filesystem(type);
9493 if (IS_ERR(mnt))
9494 return NULL;
9495 mntget(mnt);
9496
9497 return mnt;
9498}
9499
9500/**
9501 * tracing_init_dentry - initialize top level trace array
9502 *
9503 * This is called when creating files or directories in the tracing
9504 * directory. It is called via fs_initcall() by any of the boot up code
9505 * and expects to return the dentry of the top level tracing directory.
9506 */
9507int tracing_init_dentry(void)
9508{
9509 struct trace_array *tr = &global_trace;
9510
9511 if (security_locked_down(LOCKDOWN_TRACEFS)) {
9512 pr_warn("Tracing disabled due to lockdown\n");
9513 return -EPERM;
9514 }
9515
9516 /* The top level trace array uses NULL as parent */
9517 if (tr->dir)
9518 return 0;
9519
9520 if (WARN_ON(!tracefs_initialized()))
9521 return -ENODEV;
9522
9523 /*
9524 * As there may still be users that expect the tracing
9525 * files to exist in debugfs/tracing, we must automount
9526 * the tracefs file system there, so older tools still
9527 * work with the newer kernel.
9528 */
9529 tr->dir = debugfs_create_automount("tracing", NULL,
9530 trace_automount, NULL);
9531
9532 return 0;
9533}
9534
9535extern struct trace_eval_map *__start_ftrace_eval_maps[];
9536extern struct trace_eval_map *__stop_ftrace_eval_maps[];
9537
9538static struct workqueue_struct *eval_map_wq __initdata;
9539static struct work_struct eval_map_work __initdata;
9540
9541static void __init eval_map_work_func(struct work_struct *work)
9542{
9543 int len;
9544
9545 len = __stop_ftrace_eval_maps - __start_ftrace_eval_maps;
9546 trace_insert_eval_map(NULL, __start_ftrace_eval_maps, len);
9547}
9548
9549static int __init trace_eval_init(void)
9550{
9551 INIT_WORK(&eval_map_work, eval_map_work_func);
9552
9553 eval_map_wq = alloc_workqueue("eval_map_wq", WQ_UNBOUND, 0);
9554 if (!eval_map_wq) {
9555 pr_err("Unable to allocate eval_map_wq\n");
9556 /* Do work here */
9557 eval_map_work_func(&eval_map_work);
9558 return -ENOMEM;
9559 }
9560
9561 queue_work(eval_map_wq, &eval_map_work);
9562 return 0;
9563}
9564
9565static int __init trace_eval_sync(void)
9566{
9567 /* Make sure the eval map updates are finished */
9568 if (eval_map_wq)
9569 destroy_workqueue(eval_map_wq);
9570 return 0;
9571}
9572
9573late_initcall_sync(trace_eval_sync);
9574
9575
9576#ifdef CONFIG_MODULES
9577static void trace_module_add_evals(struct module *mod)
9578{
9579 if (!mod->num_trace_evals)
9580 return;
9581
9582 /*
9583 * Modules with bad taint do not have events created, do
9584 * not bother with enums either.
9585 */
9586 if (trace_module_has_bad_taint(mod))
9587 return;
9588
9589 trace_insert_eval_map(mod, mod->trace_evals, mod->num_trace_evals);
9590}
9591
9592#ifdef CONFIG_TRACE_EVAL_MAP_FILE
9593static void trace_module_remove_evals(struct module *mod)
9594{
9595 union trace_eval_map_item *map;
9596 union trace_eval_map_item **last = &trace_eval_maps;
9597
9598 if (!mod->num_trace_evals)
9599 return;
9600
9601 mutex_lock(&trace_eval_mutex);
9602
9603 map = trace_eval_maps;
9604
9605 while (map) {
9606 if (map->head.mod == mod)
9607 break;
9608 map = trace_eval_jmp_to_tail(map);
9609 last = &map->tail.next;
9610 map = map->tail.next;
9611 }
9612 if (!map)
9613 goto out;
9614
9615 *last = trace_eval_jmp_to_tail(map)->tail.next;
9616 kfree(map);
9617 out:
9618 mutex_unlock(&trace_eval_mutex);
9619}
9620#else
9621static inline void trace_module_remove_evals(struct module *mod) { }
9622#endif /* CONFIG_TRACE_EVAL_MAP_FILE */
9623
9624static int trace_module_notify(struct notifier_block *self,
9625 unsigned long val, void *data)
9626{
9627 struct module *mod = data;
9628
9629 switch (val) {
9630 case MODULE_STATE_COMING:
9631 trace_module_add_evals(mod);
9632 break;
9633 case MODULE_STATE_GOING:
9634 trace_module_remove_evals(mod);
9635 break;
9636 }
9637
9638 return NOTIFY_OK;
9639}
9640
9641static struct notifier_block trace_module_nb = {
9642 .notifier_call = trace_module_notify,
9643 .priority = 0,
9644};
9645#endif /* CONFIG_MODULES */
9646
9647static __init int tracer_init_tracefs(void)
9648{
9649 int ret;
9650
9651 trace_access_lock_init();
9652
9653 ret = tracing_init_dentry();
9654 if (ret)
9655 return 0;
9656
9657 event_trace_init();
9658
9659 init_tracer_tracefs(&global_trace, NULL);
9660 ftrace_init_tracefs_toplevel(&global_trace, NULL);
9661
9662 trace_create_file("tracing_thresh", 0644, NULL,
9663 &global_trace, &tracing_thresh_fops);
9664
9665 trace_create_file("README", 0444, NULL,
9666 NULL, &tracing_readme_fops);
9667
9668 trace_create_file("saved_cmdlines", 0444, NULL,
9669 NULL, &tracing_saved_cmdlines_fops);
9670
9671 trace_create_file("saved_cmdlines_size", 0644, NULL,
9672 NULL, &tracing_saved_cmdlines_size_fops);
9673
9674 trace_create_file("saved_tgids", 0444, NULL,
9675 NULL, &tracing_saved_tgids_fops);
9676
9677 trace_eval_init();
9678
9679 trace_create_eval_file(NULL);
9680
9681#ifdef CONFIG_MODULES
9682 register_module_notifier(&trace_module_nb);
9683#endif
9684
9685#ifdef CONFIG_DYNAMIC_FTRACE
9686 trace_create_file("dyn_ftrace_total_info", 0444, NULL,
9687 NULL, &tracing_dyn_info_fops);
9688#endif
9689
9690 create_trace_instances(NULL);
9691
9692 update_tracer_options(&global_trace);
9693
9694 return 0;
9695}
9696
9697fs_initcall(tracer_init_tracefs);
9698
9699static int trace_panic_handler(struct notifier_block *this,
9700 unsigned long event, void *unused)
9701{
9702 if (ftrace_dump_on_oops)
9703 ftrace_dump(ftrace_dump_on_oops);
9704 return NOTIFY_OK;
9705}
9706
9707static struct notifier_block trace_panic_notifier = {
9708 .notifier_call = trace_panic_handler,
9709 .next = NULL,
9710 .priority = 150 /* priority: INT_MAX >= x >= 0 */
9711};
9712
9713static int trace_die_handler(struct notifier_block *self,
9714 unsigned long val,
9715 void *data)
9716{
9717 switch (val) {
9718 case DIE_OOPS:
9719 if (ftrace_dump_on_oops)
9720 ftrace_dump(ftrace_dump_on_oops);
9721 break;
9722 default:
9723 break;
9724 }
9725 return NOTIFY_OK;
9726}
9727
9728static struct notifier_block trace_die_notifier = {
9729 .notifier_call = trace_die_handler,
9730 .priority = 200
9731};
9732
9733/*
9734 * printk is set to max of 1024, we really don't need it that big.
9735 * Nothing should be printing 1000 characters anyway.
9736 */
9737#define TRACE_MAX_PRINT 1000
9738
9739/*
9740 * Define here KERN_TRACE so that we have one place to modify
9741 * it if we decide to change what log level the ftrace dump
9742 * should be at.
9743 */
9744#define KERN_TRACE KERN_EMERG
9745
9746void
9747trace_printk_seq(struct trace_seq *s)
9748{
9749 /* Probably should print a warning here. */
9750 if (s->seq.len >= TRACE_MAX_PRINT)
9751 s->seq.len = TRACE_MAX_PRINT;
9752
9753 /*
9754 * More paranoid code. Although the buffer size is set to
9755 * PAGE_SIZE, and TRACE_MAX_PRINT is 1000, this is just
9756 * an extra layer of protection.
9757 */
9758 if (WARN_ON_ONCE(s->seq.len >= s->seq.size))
9759 s->seq.len = s->seq.size - 1;
9760
9761 /* should be zero ended, but we are paranoid. */
9762 s->buffer[s->seq.len] = 0;
9763
9764 printk(KERN_TRACE "%s", s->buffer);
9765
9766 trace_seq_init(s);
9767}
9768
9769void trace_init_global_iter(struct trace_iterator *iter)
9770{
9771 iter->tr = &global_trace;
9772 iter->trace = iter->tr->current_trace;
9773 iter->cpu_file = RING_BUFFER_ALL_CPUS;
9774 iter->array_buffer = &global_trace.array_buffer;
9775
9776 if (iter->trace && iter->trace->open)
9777 iter->trace->open(iter);
9778
9779 /* Annotate start of buffers if we had overruns */
9780 if (ring_buffer_overruns(iter->array_buffer->buffer))
9781 iter->iter_flags |= TRACE_FILE_ANNOTATE;
9782
9783 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
9784 if (trace_clocks[iter->tr->clock_id].in_ns)
9785 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
9786}
9787
9788void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
9789{
9790 /* use static because iter can be a bit big for the stack */
9791 static struct trace_iterator iter;
9792 static atomic_t dump_running;
9793 struct trace_array *tr = &global_trace;
9794 unsigned int old_userobj;
9795 unsigned long flags;
9796 int cnt = 0, cpu;
9797
9798 /* Only allow one dump user at a time. */
9799 if (atomic_inc_return(&dump_running) != 1) {
9800 atomic_dec(&dump_running);
9801 return;
9802 }
9803
9804 /*
9805 * Always turn off tracing when we dump.
9806 * We don't need to show trace output of what happens
9807 * between multiple crashes.
9808 *
9809 * If the user does a sysrq-z, then they can re-enable
9810 * tracing with echo 1 > tracing_on.
9811 */
9812 tracing_off();
9813
9814 local_irq_save(flags);
9815 printk_nmi_direct_enter();
9816
9817 /* Simulate the iterator */
9818 trace_init_global_iter(&iter);
9819 /* Can not use kmalloc for iter.temp and iter.fmt */
9820 iter.temp = static_temp_buf;
9821 iter.temp_size = STATIC_TEMP_BUF_SIZE;
9822 iter.fmt = static_fmt_buf;
9823 iter.fmt_size = STATIC_FMT_BUF_SIZE;
9824
9825 for_each_tracing_cpu(cpu) {
9826 atomic_inc(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
9827 }
9828
9829 old_userobj = tr->trace_flags & TRACE_ITER_SYM_USEROBJ;
9830
9831 /* don't look at user memory in panic mode */
9832 tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
9833
9834 switch (oops_dump_mode) {
9835 case DUMP_ALL:
9836 iter.cpu_file = RING_BUFFER_ALL_CPUS;
9837 break;
9838 case DUMP_ORIG:
9839 iter.cpu_file = raw_smp_processor_id();
9840 break;
9841 case DUMP_NONE:
9842 goto out_enable;
9843 default:
9844 printk(KERN_TRACE "Bad dumping mode, switching to all CPUs dump\n");
9845 iter.cpu_file = RING_BUFFER_ALL_CPUS;
9846 }
9847
9848 printk(KERN_TRACE "Dumping ftrace buffer:\n");
9849
9850 /* Did function tracer already get disabled? */
9851 if (ftrace_is_dead()) {
9852 printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
9853 printk("# MAY BE MISSING FUNCTION EVENTS\n");
9854 }
9855
9856 /*
9857 * We need to stop all tracing on all CPUS to read
9858 * the next buffer. This is a bit expensive, but is
9859 * not done often. We fill all what we can read,
9860 * and then release the locks again.
9861 */
9862
9863 while (!trace_empty(&iter)) {
9864
9865 if (!cnt)
9866 printk(KERN_TRACE "---------------------------------\n");
9867
9868 cnt++;
9869
9870 trace_iterator_reset(&iter);
9871 iter.iter_flags |= TRACE_FILE_LAT_FMT;
9872
9873 if (trace_find_next_entry_inc(&iter) != NULL) {
9874 int ret;
9875
9876 ret = print_trace_line(&iter);
9877 if (ret != TRACE_TYPE_NO_CONSUME)
9878 trace_consume(&iter);
9879 }
9880 touch_nmi_watchdog();
9881
9882 trace_printk_seq(&iter.seq);
9883 }
9884
9885 if (!cnt)
9886 printk(KERN_TRACE " (ftrace buffer empty)\n");
9887 else
9888 printk(KERN_TRACE "---------------------------------\n");
9889
9890 out_enable:
9891 tr->trace_flags |= old_userobj;
9892
9893 for_each_tracing_cpu(cpu) {
9894 atomic_dec(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
9895 }
9896 atomic_dec(&dump_running);
9897 printk_nmi_direct_exit();
9898 local_irq_restore(flags);
9899}
9900EXPORT_SYMBOL_GPL(ftrace_dump);
9901
9902#define WRITE_BUFSIZE 4096
9903
9904ssize_t trace_parse_run_command(struct file *file, const char __user *buffer,
9905 size_t count, loff_t *ppos,
9906 int (*createfn)(const char *))
9907{
9908 char *kbuf, *buf, *tmp;
9909 int ret = 0;
9910 size_t done = 0;
9911 size_t size;
9912
9913 kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
9914 if (!kbuf)
9915 return -ENOMEM;
9916
9917 while (done < count) {
9918 size = count - done;
9919
9920 if (size >= WRITE_BUFSIZE)
9921 size = WRITE_BUFSIZE - 1;
9922
9923 if (copy_from_user(kbuf, buffer + done, size)) {
9924 ret = -EFAULT;
9925 goto out;
9926 }
9927 kbuf[size] = '\0';
9928 buf = kbuf;
9929 do {
9930 tmp = strchr(buf, '\n');
9931 if (tmp) {
9932 *tmp = '\0';
9933 size = tmp - buf + 1;
9934 } else {
9935 size = strlen(buf);
9936 if (done + size < count) {
9937 if (buf != kbuf)
9938 break;
9939 /* This can accept WRITE_BUFSIZE - 2 ('\n' + '\0') */
9940 pr_warn("Line length is too long: Should be less than %d\n",
9941 WRITE_BUFSIZE - 2);
9942 ret = -EINVAL;
9943 goto out;
9944 }
9945 }
9946 done += size;
9947
9948 /* Remove comments */
9949 tmp = strchr(buf, '#');
9950
9951 if (tmp)
9952 *tmp = '\0';
9953
9954 ret = createfn(buf);
9955 if (ret)
9956 goto out;
9957 buf += size;
9958
9959 } while (done < count);
9960 }
9961 ret = done;
9962
9963out:
9964 kfree(kbuf);
9965
9966 return ret;
9967}
9968
9969__init static int tracer_alloc_buffers(void)
9970{
9971 int ring_buf_size;
9972 int ret = -ENOMEM;
9973
9974
9975 if (security_locked_down(LOCKDOWN_TRACEFS)) {
9976 pr_warn("Tracing disabled due to lockdown\n");
9977 return -EPERM;
9978 }
9979
9980 /*
9981 * Make sure we don't accidentally add more trace options
9982 * than we have bits for.
9983 */
9984 BUILD_BUG_ON(TRACE_ITER_LAST_BIT > TRACE_FLAGS_MAX_SIZE);
9985
9986 if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
9987 goto out;
9988
9989 if (!alloc_cpumask_var(&global_trace.tracing_cpumask, GFP_KERNEL))
9990 goto out_free_buffer_mask;
9991
9992 /* Only allocate trace_printk buffers if a trace_printk exists */
9993 if (&__stop___trace_bprintk_fmt != &__start___trace_bprintk_fmt)
9994 /* Must be called before global_trace.buffer is allocated */
9995 trace_printk_init_buffers();
9996
9997 /* To save memory, keep the ring buffer size to its minimum */
9998 if (ring_buffer_expanded)
9999 ring_buf_size = trace_buf_size;
10000 else
10001 ring_buf_size = 1;
10002
10003 cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
10004 cpumask_copy(global_trace.tracing_cpumask, cpu_all_mask);
10005
10006 raw_spin_lock_init(&global_trace.start_lock);
10007
10008 /*
10009 * The prepare callbacks allocates some memory for the ring buffer. We
10010 * don't free the buffer if the CPU goes down. If we were to free
10011 * the buffer, then the user would lose any trace that was in the
10012 * buffer. The memory will be removed once the "instance" is removed.
10013 */
10014 ret = cpuhp_setup_state_multi(CPUHP_TRACE_RB_PREPARE,
10015 "trace/RB:preapre", trace_rb_cpu_prepare,
10016 NULL);
10017 if (ret < 0)
10018 goto out_free_cpumask;
10019 /* Used for event triggers */
10020 ret = -ENOMEM;
10021 temp_buffer = ring_buffer_alloc(PAGE_SIZE, RB_FL_OVERWRITE);
10022 if (!temp_buffer)
10023 goto out_rm_hp_state;
10024
10025 if (trace_create_savedcmd() < 0)
10026 goto out_free_temp_buffer;
10027
10028 /* TODO: make the number of buffers hot pluggable with CPUS */
10029 if (allocate_trace_buffers(&global_trace, ring_buf_size) < 0) {
10030 MEM_FAIL(1, "tracer: failed to allocate ring buffer!\n");
10031 goto out_free_savedcmd;
10032 }
10033
10034 if (global_trace.buffer_disabled)
10035 tracing_off();
10036
10037 if (trace_boot_clock) {
10038 ret = tracing_set_clock(&global_trace, trace_boot_clock);
10039 if (ret < 0)
10040 pr_warn("Trace clock %s not defined, going back to default\n",
10041 trace_boot_clock);
10042 }
10043
10044 /*
10045 * register_tracer() might reference current_trace, so it
10046 * needs to be set before we register anything. This is
10047 * just a bootstrap of current_trace anyway.
10048 */
10049 global_trace.current_trace = &nop_trace;
10050
10051 global_trace.max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
10052
10053 ftrace_init_global_array_ops(&global_trace);
10054
10055 init_trace_flags_index(&global_trace);
10056
10057 register_tracer(&nop_trace);
10058
10059 /* Function tracing may start here (via kernel command line) */
10060 init_function_trace();
10061
10062 /* All seems OK, enable tracing */
10063 tracing_disabled = 0;
10064
10065 atomic_notifier_chain_register(&panic_notifier_list,
10066 &trace_panic_notifier);
10067
10068 register_die_notifier(&trace_die_notifier);
10069
10070 global_trace.flags = TRACE_ARRAY_FL_GLOBAL;
10071
10072 INIT_LIST_HEAD(&global_trace.systems);
10073 INIT_LIST_HEAD(&global_trace.events);
10074 INIT_LIST_HEAD(&global_trace.hist_vars);
10075 INIT_LIST_HEAD(&global_trace.err_log);
10076 list_add(&global_trace.list, &ftrace_trace_arrays);
10077
10078 apply_trace_boot_options();
10079
10080 register_snapshot_cmd();
10081
10082 test_can_verify();
10083
10084 return 0;
10085
10086out_free_savedcmd:
10087 free_saved_cmdlines_buffer(savedcmd);
10088out_free_temp_buffer:
10089 ring_buffer_free(temp_buffer);
10090out_rm_hp_state:
10091 cpuhp_remove_multi_state(CPUHP_TRACE_RB_PREPARE);
10092out_free_cpumask:
10093 free_cpumask_var(global_trace.tracing_cpumask);
10094out_free_buffer_mask:
10095 free_cpumask_var(tracing_buffer_mask);
10096out:
10097 return ret;
10098}
10099
10100void __init early_trace_init(void)
10101{
10102 if (tracepoint_printk) {
10103 tracepoint_print_iter =
10104 kzalloc(sizeof(*tracepoint_print_iter), GFP_KERNEL);
10105 if (MEM_FAIL(!tracepoint_print_iter,
10106 "Failed to allocate trace iterator\n"))
10107 tracepoint_printk = 0;
10108 else
10109 static_key_enable(&tracepoint_printk_key.key);
10110 }
10111 tracer_alloc_buffers();
10112}
10113
10114void __init trace_init(void)
10115{
10116 trace_event_init();
10117}
10118
10119__init static void clear_boot_tracer(void)
10120{
10121 /*
10122 * The default tracer at boot buffer is an init section.
10123 * This function is called in lateinit. If we did not
10124 * find the boot tracer, then clear it out, to prevent
10125 * later registration from accessing the buffer that is
10126 * about to be freed.
10127 */
10128 if (!default_bootup_tracer)
10129 return;
10130
10131 printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n",
10132 default_bootup_tracer);
10133 default_bootup_tracer = NULL;
10134}
10135
10136#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
10137__init static void tracing_set_default_clock(void)
10138{
10139 /* sched_clock_stable() is determined in late_initcall */
10140 if (!trace_boot_clock && !sched_clock_stable()) {
10141 if (security_locked_down(LOCKDOWN_TRACEFS)) {
10142 pr_warn("Can not set tracing clock due to lockdown\n");
10143 return;
10144 }
10145
10146 printk(KERN_WARNING
10147 "Unstable clock detected, switching default tracing clock to \"global\"\n"
10148 "If you want to keep using the local clock, then add:\n"
10149 " \"trace_clock=local\"\n"
10150 "on the kernel command line\n");
10151 tracing_set_clock(&global_trace, "global");
10152 }
10153}
10154#else
10155static inline void tracing_set_default_clock(void) { }
10156#endif
10157
10158__init static int late_trace_init(void)
10159{
10160 if (tracepoint_printk && tracepoint_printk_stop_on_boot) {
10161 static_key_disable(&tracepoint_printk_key.key);
10162 tracepoint_printk = 0;
10163 }
10164
10165 tracing_set_default_clock();
10166 clear_boot_tracer();
10167 return 0;
10168}
10169
10170late_initcall_sync(late_trace_init);