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1#include <trace/syscall.h>
2#include <trace/events/syscalls.h>
3#include <linux/syscalls.h>
4#include <linux/slab.h>
5#include <linux/kernel.h>
6#include <linux/module.h> /* for MODULE_NAME_LEN via KSYM_SYMBOL_LEN */
7#include <linux/ftrace.h>
8#include <linux/perf_event.h>
9#include <asm/syscall.h>
10
11#include "trace_output.h"
12#include "trace.h"
13
14static DEFINE_MUTEX(syscall_trace_lock);
15
16static int syscall_enter_register(struct ftrace_event_call *event,
17 enum trace_reg type, void *data);
18static int syscall_exit_register(struct ftrace_event_call *event,
19 enum trace_reg type, void *data);
20
21static struct list_head *
22syscall_get_enter_fields(struct ftrace_event_call *call)
23{
24 struct syscall_metadata *entry = call->data;
25
26 return &entry->enter_fields;
27}
28
29extern struct syscall_metadata *__start_syscalls_metadata[];
30extern struct syscall_metadata *__stop_syscalls_metadata[];
31
32static struct syscall_metadata **syscalls_metadata;
33
34#ifndef ARCH_HAS_SYSCALL_MATCH_SYM_NAME
35static inline bool arch_syscall_match_sym_name(const char *sym, const char *name)
36{
37 /*
38 * Only compare after the "sys" prefix. Archs that use
39 * syscall wrappers may have syscalls symbols aliases prefixed
40 * with ".SyS" or ".sys" instead of "sys", leading to an unwanted
41 * mismatch.
42 */
43 return !strcmp(sym + 3, name + 3);
44}
45#endif
46
47#ifdef ARCH_TRACE_IGNORE_COMPAT_SYSCALLS
48/*
49 * Some architectures that allow for 32bit applications
50 * to run on a 64bit kernel, do not map the syscalls for
51 * the 32bit tasks the same as they do for 64bit tasks.
52 *
53 * *cough*x86*cough*
54 *
55 * In such a case, instead of reporting the wrong syscalls,
56 * simply ignore them.
57 *
58 * For an arch to ignore the compat syscalls it needs to
59 * define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS as well as
60 * define the function arch_trace_is_compat_syscall() to let
61 * the tracing system know that it should ignore it.
62 */
63static int
64trace_get_syscall_nr(struct task_struct *task, struct pt_regs *regs)
65{
66 if (unlikely(arch_trace_is_compat_syscall(regs)))
67 return -1;
68
69 return syscall_get_nr(task, regs);
70}
71#else
72static inline int
73trace_get_syscall_nr(struct task_struct *task, struct pt_regs *regs)
74{
75 return syscall_get_nr(task, regs);
76}
77#endif /* ARCH_TRACE_IGNORE_COMPAT_SYSCALLS */
78
79static __init struct syscall_metadata *
80find_syscall_meta(unsigned long syscall)
81{
82 struct syscall_metadata **start;
83 struct syscall_metadata **stop;
84 char str[KSYM_SYMBOL_LEN];
85
86
87 start = __start_syscalls_metadata;
88 stop = __stop_syscalls_metadata;
89 kallsyms_lookup(syscall, NULL, NULL, NULL, str);
90
91 if (arch_syscall_match_sym_name(str, "sys_ni_syscall"))
92 return NULL;
93
94 for ( ; start < stop; start++) {
95 if ((*start)->name && arch_syscall_match_sym_name(str, (*start)->name))
96 return *start;
97 }
98 return NULL;
99}
100
101static struct syscall_metadata *syscall_nr_to_meta(int nr)
102{
103 if (!syscalls_metadata || nr >= NR_syscalls || nr < 0)
104 return NULL;
105
106 return syscalls_metadata[nr];
107}
108
109static enum print_line_t
110print_syscall_enter(struct trace_iterator *iter, int flags,
111 struct trace_event *event)
112{
113 struct trace_seq *s = &iter->seq;
114 struct trace_entry *ent = iter->ent;
115 struct syscall_trace_enter *trace;
116 struct syscall_metadata *entry;
117 int i, ret, syscall;
118
119 trace = (typeof(trace))ent;
120 syscall = trace->nr;
121 entry = syscall_nr_to_meta(syscall);
122
123 if (!entry)
124 goto end;
125
126 if (entry->enter_event->event.type != ent->type) {
127 WARN_ON_ONCE(1);
128 goto end;
129 }
130
131 ret = trace_seq_printf(s, "%s(", entry->name);
132 if (!ret)
133 return TRACE_TYPE_PARTIAL_LINE;
134
135 for (i = 0; i < entry->nb_args; i++) {
136 /* parameter types */
137 if (trace_flags & TRACE_ITER_VERBOSE) {
138 ret = trace_seq_printf(s, "%s ", entry->types[i]);
139 if (!ret)
140 return TRACE_TYPE_PARTIAL_LINE;
141 }
142 /* parameter values */
143 ret = trace_seq_printf(s, "%s: %lx%s", entry->args[i],
144 trace->args[i],
145 i == entry->nb_args - 1 ? "" : ", ");
146 if (!ret)
147 return TRACE_TYPE_PARTIAL_LINE;
148 }
149
150 ret = trace_seq_putc(s, ')');
151 if (!ret)
152 return TRACE_TYPE_PARTIAL_LINE;
153
154end:
155 ret = trace_seq_putc(s, '\n');
156 if (!ret)
157 return TRACE_TYPE_PARTIAL_LINE;
158
159 return TRACE_TYPE_HANDLED;
160}
161
162static enum print_line_t
163print_syscall_exit(struct trace_iterator *iter, int flags,
164 struct trace_event *event)
165{
166 struct trace_seq *s = &iter->seq;
167 struct trace_entry *ent = iter->ent;
168 struct syscall_trace_exit *trace;
169 int syscall;
170 struct syscall_metadata *entry;
171 int ret;
172
173 trace = (typeof(trace))ent;
174 syscall = trace->nr;
175 entry = syscall_nr_to_meta(syscall);
176
177 if (!entry) {
178 trace_seq_putc(s, '\n');
179 return TRACE_TYPE_HANDLED;
180 }
181
182 if (entry->exit_event->event.type != ent->type) {
183 WARN_ON_ONCE(1);
184 return TRACE_TYPE_UNHANDLED;
185 }
186
187 ret = trace_seq_printf(s, "%s -> 0x%lx\n", entry->name,
188 trace->ret);
189 if (!ret)
190 return TRACE_TYPE_PARTIAL_LINE;
191
192 return TRACE_TYPE_HANDLED;
193}
194
195extern char *__bad_type_size(void);
196
197#define SYSCALL_FIELD(type, name) \
198 sizeof(type) != sizeof(trace.name) ? \
199 __bad_type_size() : \
200 #type, #name, offsetof(typeof(trace), name), \
201 sizeof(trace.name), is_signed_type(type)
202
203static int __init
204__set_enter_print_fmt(struct syscall_metadata *entry, char *buf, int len)
205{
206 int i;
207 int pos = 0;
208
209 /* When len=0, we just calculate the needed length */
210#define LEN_OR_ZERO (len ? len - pos : 0)
211
212 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
213 for (i = 0; i < entry->nb_args; i++) {
214 pos += snprintf(buf + pos, LEN_OR_ZERO, "%s: 0x%%0%zulx%s",
215 entry->args[i], sizeof(unsigned long),
216 i == entry->nb_args - 1 ? "" : ", ");
217 }
218 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
219
220 for (i = 0; i < entry->nb_args; i++) {
221 pos += snprintf(buf + pos, LEN_OR_ZERO,
222 ", ((unsigned long)(REC->%s))", entry->args[i]);
223 }
224
225#undef LEN_OR_ZERO
226
227 /* return the length of print_fmt */
228 return pos;
229}
230
231static int __init set_syscall_print_fmt(struct ftrace_event_call *call)
232{
233 char *print_fmt;
234 int len;
235 struct syscall_metadata *entry = call->data;
236
237 if (entry->enter_event != call) {
238 call->print_fmt = "\"0x%lx\", REC->ret";
239 return 0;
240 }
241
242 /* First: called with 0 length to calculate the needed length */
243 len = __set_enter_print_fmt(entry, NULL, 0);
244
245 print_fmt = kmalloc(len + 1, GFP_KERNEL);
246 if (!print_fmt)
247 return -ENOMEM;
248
249 /* Second: actually write the @print_fmt */
250 __set_enter_print_fmt(entry, print_fmt, len + 1);
251 call->print_fmt = print_fmt;
252
253 return 0;
254}
255
256static void __init free_syscall_print_fmt(struct ftrace_event_call *call)
257{
258 struct syscall_metadata *entry = call->data;
259
260 if (entry->enter_event == call)
261 kfree(call->print_fmt);
262}
263
264static int __init syscall_enter_define_fields(struct ftrace_event_call *call)
265{
266 struct syscall_trace_enter trace;
267 struct syscall_metadata *meta = call->data;
268 int ret;
269 int i;
270 int offset = offsetof(typeof(trace), args);
271
272 ret = trace_define_field(call, SYSCALL_FIELD(int, nr), FILTER_OTHER);
273 if (ret)
274 return ret;
275
276 for (i = 0; i < meta->nb_args; i++) {
277 ret = trace_define_field(call, meta->types[i],
278 meta->args[i], offset,
279 sizeof(unsigned long), 0,
280 FILTER_OTHER);
281 offset += sizeof(unsigned long);
282 }
283
284 return ret;
285}
286
287static int __init syscall_exit_define_fields(struct ftrace_event_call *call)
288{
289 struct syscall_trace_exit trace;
290 int ret;
291
292 ret = trace_define_field(call, SYSCALL_FIELD(int, nr), FILTER_OTHER);
293 if (ret)
294 return ret;
295
296 ret = trace_define_field(call, SYSCALL_FIELD(long, ret),
297 FILTER_OTHER);
298
299 return ret;
300}
301
302static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
303{
304 struct trace_array *tr = data;
305 struct ftrace_event_file *ftrace_file;
306 struct syscall_trace_enter *entry;
307 struct syscall_metadata *sys_data;
308 struct ring_buffer_event *event;
309 struct ring_buffer *buffer;
310 unsigned long irq_flags;
311 int pc;
312 int syscall_nr;
313 int size;
314
315 syscall_nr = trace_get_syscall_nr(current, regs);
316 if (syscall_nr < 0)
317 return;
318
319 /* Here we're inside tp handler's rcu_read_lock_sched (__DO_TRACE) */
320 ftrace_file = rcu_dereference_sched(tr->enter_syscall_files[syscall_nr]);
321 if (!ftrace_file)
322 return;
323
324 if (ftrace_trigger_soft_disabled(ftrace_file))
325 return;
326
327 sys_data = syscall_nr_to_meta(syscall_nr);
328 if (!sys_data)
329 return;
330
331 size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args;
332
333 local_save_flags(irq_flags);
334 pc = preempt_count();
335
336 buffer = tr->trace_buffer.buffer;
337 event = trace_buffer_lock_reserve(buffer,
338 sys_data->enter_event->event.type, size, irq_flags, pc);
339 if (!event)
340 return;
341
342 entry = ring_buffer_event_data(event);
343 entry->nr = syscall_nr;
344 syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args);
345
346 event_trigger_unlock_commit(ftrace_file, buffer, event, entry,
347 irq_flags, pc);
348}
349
350static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret)
351{
352 struct trace_array *tr = data;
353 struct ftrace_event_file *ftrace_file;
354 struct syscall_trace_exit *entry;
355 struct syscall_metadata *sys_data;
356 struct ring_buffer_event *event;
357 struct ring_buffer *buffer;
358 unsigned long irq_flags;
359 int pc;
360 int syscall_nr;
361
362 syscall_nr = trace_get_syscall_nr(current, regs);
363 if (syscall_nr < 0)
364 return;
365
366 /* Here we're inside tp handler's rcu_read_lock_sched (__DO_TRACE()) */
367 ftrace_file = rcu_dereference_sched(tr->exit_syscall_files[syscall_nr]);
368 if (!ftrace_file)
369 return;
370
371 if (ftrace_trigger_soft_disabled(ftrace_file))
372 return;
373
374 sys_data = syscall_nr_to_meta(syscall_nr);
375 if (!sys_data)
376 return;
377
378 local_save_flags(irq_flags);
379 pc = preempt_count();
380
381 buffer = tr->trace_buffer.buffer;
382 event = trace_buffer_lock_reserve(buffer,
383 sys_data->exit_event->event.type, sizeof(*entry),
384 irq_flags, pc);
385 if (!event)
386 return;
387
388 entry = ring_buffer_event_data(event);
389 entry->nr = syscall_nr;
390 entry->ret = syscall_get_return_value(current, regs);
391
392 event_trigger_unlock_commit(ftrace_file, buffer, event, entry,
393 irq_flags, pc);
394}
395
396static int reg_event_syscall_enter(struct ftrace_event_file *file,
397 struct ftrace_event_call *call)
398{
399 struct trace_array *tr = file->tr;
400 int ret = 0;
401 int num;
402
403 num = ((struct syscall_metadata *)call->data)->syscall_nr;
404 if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
405 return -ENOSYS;
406 mutex_lock(&syscall_trace_lock);
407 if (!tr->sys_refcount_enter)
408 ret = register_trace_sys_enter(ftrace_syscall_enter, tr);
409 if (!ret) {
410 rcu_assign_pointer(tr->enter_syscall_files[num], file);
411 tr->sys_refcount_enter++;
412 }
413 mutex_unlock(&syscall_trace_lock);
414 return ret;
415}
416
417static void unreg_event_syscall_enter(struct ftrace_event_file *file,
418 struct ftrace_event_call *call)
419{
420 struct trace_array *tr = file->tr;
421 int num;
422
423 num = ((struct syscall_metadata *)call->data)->syscall_nr;
424 if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
425 return;
426 mutex_lock(&syscall_trace_lock);
427 tr->sys_refcount_enter--;
428 rcu_assign_pointer(tr->enter_syscall_files[num], NULL);
429 if (!tr->sys_refcount_enter)
430 unregister_trace_sys_enter(ftrace_syscall_enter, tr);
431 mutex_unlock(&syscall_trace_lock);
432}
433
434static int reg_event_syscall_exit(struct ftrace_event_file *file,
435 struct ftrace_event_call *call)
436{
437 struct trace_array *tr = file->tr;
438 int ret = 0;
439 int num;
440
441 num = ((struct syscall_metadata *)call->data)->syscall_nr;
442 if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
443 return -ENOSYS;
444 mutex_lock(&syscall_trace_lock);
445 if (!tr->sys_refcount_exit)
446 ret = register_trace_sys_exit(ftrace_syscall_exit, tr);
447 if (!ret) {
448 rcu_assign_pointer(tr->exit_syscall_files[num], file);
449 tr->sys_refcount_exit++;
450 }
451 mutex_unlock(&syscall_trace_lock);
452 return ret;
453}
454
455static void unreg_event_syscall_exit(struct ftrace_event_file *file,
456 struct ftrace_event_call *call)
457{
458 struct trace_array *tr = file->tr;
459 int num;
460
461 num = ((struct syscall_metadata *)call->data)->syscall_nr;
462 if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
463 return;
464 mutex_lock(&syscall_trace_lock);
465 tr->sys_refcount_exit--;
466 rcu_assign_pointer(tr->exit_syscall_files[num], NULL);
467 if (!tr->sys_refcount_exit)
468 unregister_trace_sys_exit(ftrace_syscall_exit, tr);
469 mutex_unlock(&syscall_trace_lock);
470}
471
472static int __init init_syscall_trace(struct ftrace_event_call *call)
473{
474 int id;
475 int num;
476
477 num = ((struct syscall_metadata *)call->data)->syscall_nr;
478 if (num < 0 || num >= NR_syscalls) {
479 pr_debug("syscall %s metadata not mapped, disabling ftrace event\n",
480 ((struct syscall_metadata *)call->data)->name);
481 return -ENOSYS;
482 }
483
484 if (set_syscall_print_fmt(call) < 0)
485 return -ENOMEM;
486
487 id = trace_event_raw_init(call);
488
489 if (id < 0) {
490 free_syscall_print_fmt(call);
491 return id;
492 }
493
494 return id;
495}
496
497struct trace_event_functions enter_syscall_print_funcs = {
498 .trace = print_syscall_enter,
499};
500
501struct trace_event_functions exit_syscall_print_funcs = {
502 .trace = print_syscall_exit,
503};
504
505struct ftrace_event_class __refdata event_class_syscall_enter = {
506 .system = "syscalls",
507 .reg = syscall_enter_register,
508 .define_fields = syscall_enter_define_fields,
509 .get_fields = syscall_get_enter_fields,
510 .raw_init = init_syscall_trace,
511};
512
513struct ftrace_event_class __refdata event_class_syscall_exit = {
514 .system = "syscalls",
515 .reg = syscall_exit_register,
516 .define_fields = syscall_exit_define_fields,
517 .fields = LIST_HEAD_INIT(event_class_syscall_exit.fields),
518 .raw_init = init_syscall_trace,
519};
520
521unsigned long __init __weak arch_syscall_addr(int nr)
522{
523 return (unsigned long)sys_call_table[nr];
524}
525
526static int __init init_ftrace_syscalls(void)
527{
528 struct syscall_metadata *meta;
529 unsigned long addr;
530 int i;
531
532 syscalls_metadata = kcalloc(NR_syscalls, sizeof(*syscalls_metadata),
533 GFP_KERNEL);
534 if (!syscalls_metadata) {
535 WARN_ON(1);
536 return -ENOMEM;
537 }
538
539 for (i = 0; i < NR_syscalls; i++) {
540 addr = arch_syscall_addr(i);
541 meta = find_syscall_meta(addr);
542 if (!meta)
543 continue;
544
545 meta->syscall_nr = i;
546 syscalls_metadata[i] = meta;
547 }
548
549 return 0;
550}
551early_initcall(init_ftrace_syscalls);
552
553#ifdef CONFIG_PERF_EVENTS
554
555static DECLARE_BITMAP(enabled_perf_enter_syscalls, NR_syscalls);
556static DECLARE_BITMAP(enabled_perf_exit_syscalls, NR_syscalls);
557static int sys_perf_refcount_enter;
558static int sys_perf_refcount_exit;
559
560static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
561{
562 struct syscall_metadata *sys_data;
563 struct syscall_trace_enter *rec;
564 struct hlist_head *head;
565 int syscall_nr;
566 int rctx;
567 int size;
568
569 syscall_nr = trace_get_syscall_nr(current, regs);
570 if (syscall_nr < 0)
571 return;
572 if (!test_bit(syscall_nr, enabled_perf_enter_syscalls))
573 return;
574
575 sys_data = syscall_nr_to_meta(syscall_nr);
576 if (!sys_data)
577 return;
578
579 head = this_cpu_ptr(sys_data->enter_event->perf_events);
580 if (hlist_empty(head))
581 return;
582
583 /* get the size after alignment with the u32 buffer size field */
584 size = sizeof(unsigned long) * sys_data->nb_args + sizeof(*rec);
585 size = ALIGN(size + sizeof(u32), sizeof(u64));
586 size -= sizeof(u32);
587
588 rec = (struct syscall_trace_enter *)perf_trace_buf_prepare(size,
589 sys_data->enter_event->event.type, regs, &rctx);
590 if (!rec)
591 return;
592
593 rec->nr = syscall_nr;
594 syscall_get_arguments(current, regs, 0, sys_data->nb_args,
595 (unsigned long *)&rec->args);
596 perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head, NULL);
597}
598
599static int perf_sysenter_enable(struct ftrace_event_call *call)
600{
601 int ret = 0;
602 int num;
603
604 num = ((struct syscall_metadata *)call->data)->syscall_nr;
605
606 mutex_lock(&syscall_trace_lock);
607 if (!sys_perf_refcount_enter)
608 ret = register_trace_sys_enter(perf_syscall_enter, NULL);
609 if (ret) {
610 pr_info("event trace: Could not activate"
611 "syscall entry trace point");
612 } else {
613 set_bit(num, enabled_perf_enter_syscalls);
614 sys_perf_refcount_enter++;
615 }
616 mutex_unlock(&syscall_trace_lock);
617 return ret;
618}
619
620static void perf_sysenter_disable(struct ftrace_event_call *call)
621{
622 int num;
623
624 num = ((struct syscall_metadata *)call->data)->syscall_nr;
625
626 mutex_lock(&syscall_trace_lock);
627 sys_perf_refcount_enter--;
628 clear_bit(num, enabled_perf_enter_syscalls);
629 if (!sys_perf_refcount_enter)
630 unregister_trace_sys_enter(perf_syscall_enter, NULL);
631 mutex_unlock(&syscall_trace_lock);
632}
633
634static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
635{
636 struct syscall_metadata *sys_data;
637 struct syscall_trace_exit *rec;
638 struct hlist_head *head;
639 int syscall_nr;
640 int rctx;
641 int size;
642
643 syscall_nr = trace_get_syscall_nr(current, regs);
644 if (syscall_nr < 0)
645 return;
646 if (!test_bit(syscall_nr, enabled_perf_exit_syscalls))
647 return;
648
649 sys_data = syscall_nr_to_meta(syscall_nr);
650 if (!sys_data)
651 return;
652
653 head = this_cpu_ptr(sys_data->exit_event->perf_events);
654 if (hlist_empty(head))
655 return;
656
657 /* We can probably do that at build time */
658 size = ALIGN(sizeof(*rec) + sizeof(u32), sizeof(u64));
659 size -= sizeof(u32);
660
661 rec = (struct syscall_trace_exit *)perf_trace_buf_prepare(size,
662 sys_data->exit_event->event.type, regs, &rctx);
663 if (!rec)
664 return;
665
666 rec->nr = syscall_nr;
667 rec->ret = syscall_get_return_value(current, regs);
668 perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head, NULL);
669}
670
671static int perf_sysexit_enable(struct ftrace_event_call *call)
672{
673 int ret = 0;
674 int num;
675
676 num = ((struct syscall_metadata *)call->data)->syscall_nr;
677
678 mutex_lock(&syscall_trace_lock);
679 if (!sys_perf_refcount_exit)
680 ret = register_trace_sys_exit(perf_syscall_exit, NULL);
681 if (ret) {
682 pr_info("event trace: Could not activate"
683 "syscall exit trace point");
684 } else {
685 set_bit(num, enabled_perf_exit_syscalls);
686 sys_perf_refcount_exit++;
687 }
688 mutex_unlock(&syscall_trace_lock);
689 return ret;
690}
691
692static void perf_sysexit_disable(struct ftrace_event_call *call)
693{
694 int num;
695
696 num = ((struct syscall_metadata *)call->data)->syscall_nr;
697
698 mutex_lock(&syscall_trace_lock);
699 sys_perf_refcount_exit--;
700 clear_bit(num, enabled_perf_exit_syscalls);
701 if (!sys_perf_refcount_exit)
702 unregister_trace_sys_exit(perf_syscall_exit, NULL);
703 mutex_unlock(&syscall_trace_lock);
704}
705
706#endif /* CONFIG_PERF_EVENTS */
707
708static int syscall_enter_register(struct ftrace_event_call *event,
709 enum trace_reg type, void *data)
710{
711 struct ftrace_event_file *file = data;
712
713 switch (type) {
714 case TRACE_REG_REGISTER:
715 return reg_event_syscall_enter(file, event);
716 case TRACE_REG_UNREGISTER:
717 unreg_event_syscall_enter(file, event);
718 return 0;
719
720#ifdef CONFIG_PERF_EVENTS
721 case TRACE_REG_PERF_REGISTER:
722 return perf_sysenter_enable(event);
723 case TRACE_REG_PERF_UNREGISTER:
724 perf_sysenter_disable(event);
725 return 0;
726 case TRACE_REG_PERF_OPEN:
727 case TRACE_REG_PERF_CLOSE:
728 case TRACE_REG_PERF_ADD:
729 case TRACE_REG_PERF_DEL:
730 return 0;
731#endif
732 }
733 return 0;
734}
735
736static int syscall_exit_register(struct ftrace_event_call *event,
737 enum trace_reg type, void *data)
738{
739 struct ftrace_event_file *file = data;
740
741 switch (type) {
742 case TRACE_REG_REGISTER:
743 return reg_event_syscall_exit(file, event);
744 case TRACE_REG_UNREGISTER:
745 unreg_event_syscall_exit(file, event);
746 return 0;
747
748#ifdef CONFIG_PERF_EVENTS
749 case TRACE_REG_PERF_REGISTER:
750 return perf_sysexit_enable(event);
751 case TRACE_REG_PERF_UNREGISTER:
752 perf_sysexit_disable(event);
753 return 0;
754 case TRACE_REG_PERF_OPEN:
755 case TRACE_REG_PERF_CLOSE:
756 case TRACE_REG_PERF_ADD:
757 case TRACE_REG_PERF_DEL:
758 return 0;
759#endif
760 }
761 return 0;
762}
1// SPDX-License-Identifier: GPL-2.0
2#include <trace/syscall.h>
3#include <trace/events/syscalls.h>
4#include <linux/syscalls.h>
5#include <linux/slab.h>
6#include <linux/kernel.h>
7#include <linux/module.h> /* for MODULE_NAME_LEN via KSYM_SYMBOL_LEN */
8#include <linux/ftrace.h>
9#include <linux/perf_event.h>
10#include <asm/syscall.h>
11
12#include "trace_output.h"
13#include "trace.h"
14
15static DEFINE_MUTEX(syscall_trace_lock);
16
17static int syscall_enter_register(struct trace_event_call *event,
18 enum trace_reg type, void *data);
19static int syscall_exit_register(struct trace_event_call *event,
20 enum trace_reg type, void *data);
21
22static struct list_head *
23syscall_get_enter_fields(struct trace_event_call *call)
24{
25 struct syscall_metadata *entry = call->data;
26
27 return &entry->enter_fields;
28}
29
30extern struct syscall_metadata *__start_syscalls_metadata[];
31extern struct syscall_metadata *__stop_syscalls_metadata[];
32
33static struct syscall_metadata **syscalls_metadata;
34
35#ifndef ARCH_HAS_SYSCALL_MATCH_SYM_NAME
36static inline bool arch_syscall_match_sym_name(const char *sym, const char *name)
37{
38 /*
39 * Only compare after the "sys" prefix. Archs that use
40 * syscall wrappers may have syscalls symbols aliases prefixed
41 * with ".SyS" or ".sys" instead of "sys", leading to an unwanted
42 * mismatch.
43 */
44 return !strcmp(sym + 3, name + 3);
45}
46#endif
47
48#ifdef ARCH_TRACE_IGNORE_COMPAT_SYSCALLS
49/*
50 * Some architectures that allow for 32bit applications
51 * to run on a 64bit kernel, do not map the syscalls for
52 * the 32bit tasks the same as they do for 64bit tasks.
53 *
54 * *cough*x86*cough*
55 *
56 * In such a case, instead of reporting the wrong syscalls,
57 * simply ignore them.
58 *
59 * For an arch to ignore the compat syscalls it needs to
60 * define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS as well as
61 * define the function arch_trace_is_compat_syscall() to let
62 * the tracing system know that it should ignore it.
63 */
64static int
65trace_get_syscall_nr(struct task_struct *task, struct pt_regs *regs)
66{
67 if (unlikely(arch_trace_is_compat_syscall(regs)))
68 return -1;
69
70 return syscall_get_nr(task, regs);
71}
72#else
73static inline int
74trace_get_syscall_nr(struct task_struct *task, struct pt_regs *regs)
75{
76 return syscall_get_nr(task, regs);
77}
78#endif /* ARCH_TRACE_IGNORE_COMPAT_SYSCALLS */
79
80static __init struct syscall_metadata *
81find_syscall_meta(unsigned long syscall)
82{
83 struct syscall_metadata **start;
84 struct syscall_metadata **stop;
85 char str[KSYM_SYMBOL_LEN];
86
87
88 start = __start_syscalls_metadata;
89 stop = __stop_syscalls_metadata;
90 kallsyms_lookup(syscall, NULL, NULL, NULL, str);
91
92 if (arch_syscall_match_sym_name(str, "sys_ni_syscall"))
93 return NULL;
94
95 for ( ; start < stop; start++) {
96 if ((*start)->name && arch_syscall_match_sym_name(str, (*start)->name))
97 return *start;
98 }
99 return NULL;
100}
101
102static struct syscall_metadata *syscall_nr_to_meta(int nr)
103{
104 if (!syscalls_metadata || nr >= NR_syscalls || nr < 0)
105 return NULL;
106
107 return syscalls_metadata[nr];
108}
109
110const char *get_syscall_name(int syscall)
111{
112 struct syscall_metadata *entry;
113
114 entry = syscall_nr_to_meta(syscall);
115 if (!entry)
116 return NULL;
117
118 return entry->name;
119}
120
121static enum print_line_t
122print_syscall_enter(struct trace_iterator *iter, int flags,
123 struct trace_event *event)
124{
125 struct trace_array *tr = iter->tr;
126 struct trace_seq *s = &iter->seq;
127 struct trace_entry *ent = iter->ent;
128 struct syscall_trace_enter *trace;
129 struct syscall_metadata *entry;
130 int i, syscall;
131
132 trace = (typeof(trace))ent;
133 syscall = trace->nr;
134 entry = syscall_nr_to_meta(syscall);
135
136 if (!entry)
137 goto end;
138
139 if (entry->enter_event->event.type != ent->type) {
140 WARN_ON_ONCE(1);
141 goto end;
142 }
143
144 trace_seq_printf(s, "%s(", entry->name);
145
146 for (i = 0; i < entry->nb_args; i++) {
147
148 if (trace_seq_has_overflowed(s))
149 goto end;
150
151 /* parameter types */
152 if (tr->trace_flags & TRACE_ITER_VERBOSE)
153 trace_seq_printf(s, "%s ", entry->types[i]);
154
155 /* parameter values */
156 trace_seq_printf(s, "%s: %lx%s", entry->args[i],
157 trace->args[i],
158 i == entry->nb_args - 1 ? "" : ", ");
159 }
160
161 trace_seq_putc(s, ')');
162end:
163 trace_seq_putc(s, '\n');
164
165 return trace_handle_return(s);
166}
167
168static enum print_line_t
169print_syscall_exit(struct trace_iterator *iter, int flags,
170 struct trace_event *event)
171{
172 struct trace_seq *s = &iter->seq;
173 struct trace_entry *ent = iter->ent;
174 struct syscall_trace_exit *trace;
175 int syscall;
176 struct syscall_metadata *entry;
177
178 trace = (typeof(trace))ent;
179 syscall = trace->nr;
180 entry = syscall_nr_to_meta(syscall);
181
182 if (!entry) {
183 trace_seq_putc(s, '\n');
184 goto out;
185 }
186
187 if (entry->exit_event->event.type != ent->type) {
188 WARN_ON_ONCE(1);
189 return TRACE_TYPE_UNHANDLED;
190 }
191
192 trace_seq_printf(s, "%s -> 0x%lx\n", entry->name,
193 trace->ret);
194
195 out:
196 return trace_handle_return(s);
197}
198
199extern char *__bad_type_size(void);
200
201#define SYSCALL_FIELD(type, field, name) \
202 sizeof(type) != sizeof(trace.field) ? \
203 __bad_type_size() : \
204 #type, #name, offsetof(typeof(trace), field), \
205 sizeof(trace.field), is_signed_type(type)
206
207static int __init
208__set_enter_print_fmt(struct syscall_metadata *entry, char *buf, int len)
209{
210 int i;
211 int pos = 0;
212
213 /* When len=0, we just calculate the needed length */
214#define LEN_OR_ZERO (len ? len - pos : 0)
215
216 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
217 for (i = 0; i < entry->nb_args; i++) {
218 pos += snprintf(buf + pos, LEN_OR_ZERO, "%s: 0x%%0%zulx%s",
219 entry->args[i], sizeof(unsigned long),
220 i == entry->nb_args - 1 ? "" : ", ");
221 }
222 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
223
224 for (i = 0; i < entry->nb_args; i++) {
225 pos += snprintf(buf + pos, LEN_OR_ZERO,
226 ", ((unsigned long)(REC->%s))", entry->args[i]);
227 }
228
229#undef LEN_OR_ZERO
230
231 /* return the length of print_fmt */
232 return pos;
233}
234
235static int __init set_syscall_print_fmt(struct trace_event_call *call)
236{
237 char *print_fmt;
238 int len;
239 struct syscall_metadata *entry = call->data;
240
241 if (entry->enter_event != call) {
242 call->print_fmt = "\"0x%lx\", REC->ret";
243 return 0;
244 }
245
246 /* First: called with 0 length to calculate the needed length */
247 len = __set_enter_print_fmt(entry, NULL, 0);
248
249 print_fmt = kmalloc(len + 1, GFP_KERNEL);
250 if (!print_fmt)
251 return -ENOMEM;
252
253 /* Second: actually write the @print_fmt */
254 __set_enter_print_fmt(entry, print_fmt, len + 1);
255 call->print_fmt = print_fmt;
256
257 return 0;
258}
259
260static void __init free_syscall_print_fmt(struct trace_event_call *call)
261{
262 struct syscall_metadata *entry = call->data;
263
264 if (entry->enter_event == call)
265 kfree(call->print_fmt);
266}
267
268static int __init syscall_enter_define_fields(struct trace_event_call *call)
269{
270 struct syscall_trace_enter trace;
271 struct syscall_metadata *meta = call->data;
272 int ret;
273 int i;
274 int offset = offsetof(typeof(trace), args);
275
276 ret = trace_define_field(call, SYSCALL_FIELD(int, nr, __syscall_nr),
277 FILTER_OTHER);
278 if (ret)
279 return ret;
280
281 for (i = 0; i < meta->nb_args; i++) {
282 ret = trace_define_field(call, meta->types[i],
283 meta->args[i], offset,
284 sizeof(unsigned long), 0,
285 FILTER_OTHER);
286 offset += sizeof(unsigned long);
287 }
288
289 return ret;
290}
291
292static int __init syscall_exit_define_fields(struct trace_event_call *call)
293{
294 struct syscall_trace_exit trace;
295 int ret;
296
297 ret = trace_define_field(call, SYSCALL_FIELD(int, nr, __syscall_nr),
298 FILTER_OTHER);
299 if (ret)
300 return ret;
301
302 ret = trace_define_field(call, SYSCALL_FIELD(long, ret, ret),
303 FILTER_OTHER);
304
305 return ret;
306}
307
308static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
309{
310 struct trace_array *tr = data;
311 struct trace_event_file *trace_file;
312 struct syscall_trace_enter *entry;
313 struct syscall_metadata *sys_data;
314 struct ring_buffer_event *event;
315 struct ring_buffer *buffer;
316 unsigned long irq_flags;
317 int pc;
318 int syscall_nr;
319 int size;
320
321 syscall_nr = trace_get_syscall_nr(current, regs);
322 if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
323 return;
324
325 /* Here we're inside tp handler's rcu_read_lock_sched (__DO_TRACE) */
326 trace_file = rcu_dereference_sched(tr->enter_syscall_files[syscall_nr]);
327 if (!trace_file)
328 return;
329
330 if (trace_trigger_soft_disabled(trace_file))
331 return;
332
333 sys_data = syscall_nr_to_meta(syscall_nr);
334 if (!sys_data)
335 return;
336
337 size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args;
338
339 local_save_flags(irq_flags);
340 pc = preempt_count();
341
342 buffer = tr->trace_buffer.buffer;
343 event = trace_buffer_lock_reserve(buffer,
344 sys_data->enter_event->event.type, size, irq_flags, pc);
345 if (!event)
346 return;
347
348 entry = ring_buffer_event_data(event);
349 entry->nr = syscall_nr;
350 syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args);
351
352 event_trigger_unlock_commit(trace_file, buffer, event, entry,
353 irq_flags, pc);
354}
355
356static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret)
357{
358 struct trace_array *tr = data;
359 struct trace_event_file *trace_file;
360 struct syscall_trace_exit *entry;
361 struct syscall_metadata *sys_data;
362 struct ring_buffer_event *event;
363 struct ring_buffer *buffer;
364 unsigned long irq_flags;
365 int pc;
366 int syscall_nr;
367
368 syscall_nr = trace_get_syscall_nr(current, regs);
369 if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
370 return;
371
372 /* Here we're inside tp handler's rcu_read_lock_sched (__DO_TRACE()) */
373 trace_file = rcu_dereference_sched(tr->exit_syscall_files[syscall_nr]);
374 if (!trace_file)
375 return;
376
377 if (trace_trigger_soft_disabled(trace_file))
378 return;
379
380 sys_data = syscall_nr_to_meta(syscall_nr);
381 if (!sys_data)
382 return;
383
384 local_save_flags(irq_flags);
385 pc = preempt_count();
386
387 buffer = tr->trace_buffer.buffer;
388 event = trace_buffer_lock_reserve(buffer,
389 sys_data->exit_event->event.type, sizeof(*entry),
390 irq_flags, pc);
391 if (!event)
392 return;
393
394 entry = ring_buffer_event_data(event);
395 entry->nr = syscall_nr;
396 entry->ret = syscall_get_return_value(current, regs);
397
398 event_trigger_unlock_commit(trace_file, buffer, event, entry,
399 irq_flags, pc);
400}
401
402static int reg_event_syscall_enter(struct trace_event_file *file,
403 struct trace_event_call *call)
404{
405 struct trace_array *tr = file->tr;
406 int ret = 0;
407 int num;
408
409 num = ((struct syscall_metadata *)call->data)->syscall_nr;
410 if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
411 return -ENOSYS;
412 mutex_lock(&syscall_trace_lock);
413 if (!tr->sys_refcount_enter)
414 ret = register_trace_sys_enter(ftrace_syscall_enter, tr);
415 if (!ret) {
416 rcu_assign_pointer(tr->enter_syscall_files[num], file);
417 tr->sys_refcount_enter++;
418 }
419 mutex_unlock(&syscall_trace_lock);
420 return ret;
421}
422
423static void unreg_event_syscall_enter(struct trace_event_file *file,
424 struct trace_event_call *call)
425{
426 struct trace_array *tr = file->tr;
427 int num;
428
429 num = ((struct syscall_metadata *)call->data)->syscall_nr;
430 if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
431 return;
432 mutex_lock(&syscall_trace_lock);
433 tr->sys_refcount_enter--;
434 RCU_INIT_POINTER(tr->enter_syscall_files[num], NULL);
435 if (!tr->sys_refcount_enter)
436 unregister_trace_sys_enter(ftrace_syscall_enter, tr);
437 mutex_unlock(&syscall_trace_lock);
438}
439
440static int reg_event_syscall_exit(struct trace_event_file *file,
441 struct trace_event_call *call)
442{
443 struct trace_array *tr = file->tr;
444 int ret = 0;
445 int num;
446
447 num = ((struct syscall_metadata *)call->data)->syscall_nr;
448 if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
449 return -ENOSYS;
450 mutex_lock(&syscall_trace_lock);
451 if (!tr->sys_refcount_exit)
452 ret = register_trace_sys_exit(ftrace_syscall_exit, tr);
453 if (!ret) {
454 rcu_assign_pointer(tr->exit_syscall_files[num], file);
455 tr->sys_refcount_exit++;
456 }
457 mutex_unlock(&syscall_trace_lock);
458 return ret;
459}
460
461static void unreg_event_syscall_exit(struct trace_event_file *file,
462 struct trace_event_call *call)
463{
464 struct trace_array *tr = file->tr;
465 int num;
466
467 num = ((struct syscall_metadata *)call->data)->syscall_nr;
468 if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
469 return;
470 mutex_lock(&syscall_trace_lock);
471 tr->sys_refcount_exit--;
472 RCU_INIT_POINTER(tr->exit_syscall_files[num], NULL);
473 if (!tr->sys_refcount_exit)
474 unregister_trace_sys_exit(ftrace_syscall_exit, tr);
475 mutex_unlock(&syscall_trace_lock);
476}
477
478static int __init init_syscall_trace(struct trace_event_call *call)
479{
480 int id;
481 int num;
482
483 num = ((struct syscall_metadata *)call->data)->syscall_nr;
484 if (num < 0 || num >= NR_syscalls) {
485 pr_debug("syscall %s metadata not mapped, disabling ftrace event\n",
486 ((struct syscall_metadata *)call->data)->name);
487 return -ENOSYS;
488 }
489
490 if (set_syscall_print_fmt(call) < 0)
491 return -ENOMEM;
492
493 id = trace_event_raw_init(call);
494
495 if (id < 0) {
496 free_syscall_print_fmt(call);
497 return id;
498 }
499
500 return id;
501}
502
503struct trace_event_functions enter_syscall_print_funcs = {
504 .trace = print_syscall_enter,
505};
506
507struct trace_event_functions exit_syscall_print_funcs = {
508 .trace = print_syscall_exit,
509};
510
511struct trace_event_class __refdata event_class_syscall_enter = {
512 .system = "syscalls",
513 .reg = syscall_enter_register,
514 .define_fields = syscall_enter_define_fields,
515 .get_fields = syscall_get_enter_fields,
516 .raw_init = init_syscall_trace,
517};
518
519struct trace_event_class __refdata event_class_syscall_exit = {
520 .system = "syscalls",
521 .reg = syscall_exit_register,
522 .define_fields = syscall_exit_define_fields,
523 .fields = LIST_HEAD_INIT(event_class_syscall_exit.fields),
524 .raw_init = init_syscall_trace,
525};
526
527unsigned long __init __weak arch_syscall_addr(int nr)
528{
529 return (unsigned long)sys_call_table[nr];
530}
531
532void __init init_ftrace_syscalls(void)
533{
534 struct syscall_metadata *meta;
535 unsigned long addr;
536 int i;
537
538 syscalls_metadata = kcalloc(NR_syscalls, sizeof(*syscalls_metadata),
539 GFP_KERNEL);
540 if (!syscalls_metadata) {
541 WARN_ON(1);
542 return;
543 }
544
545 for (i = 0; i < NR_syscalls; i++) {
546 addr = arch_syscall_addr(i);
547 meta = find_syscall_meta(addr);
548 if (!meta)
549 continue;
550
551 meta->syscall_nr = i;
552 syscalls_metadata[i] = meta;
553 }
554}
555
556#ifdef CONFIG_PERF_EVENTS
557
558static DECLARE_BITMAP(enabled_perf_enter_syscalls, NR_syscalls);
559static DECLARE_BITMAP(enabled_perf_exit_syscalls, NR_syscalls);
560static int sys_perf_refcount_enter;
561static int sys_perf_refcount_exit;
562
563static int perf_call_bpf_enter(struct trace_event_call *call, struct pt_regs *regs,
564 struct syscall_metadata *sys_data,
565 struct syscall_trace_enter *rec)
566{
567 struct syscall_tp_t {
568 unsigned long long regs;
569 unsigned long syscall_nr;
570 unsigned long args[SYSCALL_DEFINE_MAXARGS];
571 } param;
572 int i;
573
574 *(struct pt_regs **)¶m = regs;
575 param.syscall_nr = rec->nr;
576 for (i = 0; i < sys_data->nb_args; i++)
577 param.args[i] = rec->args[i];
578 return trace_call_bpf(call, ¶m);
579}
580
581static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
582{
583 struct syscall_metadata *sys_data;
584 struct syscall_trace_enter *rec;
585 struct hlist_head *head;
586 bool valid_prog_array;
587 int syscall_nr;
588 int rctx;
589 int size;
590
591 syscall_nr = trace_get_syscall_nr(current, regs);
592 if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
593 return;
594 if (!test_bit(syscall_nr, enabled_perf_enter_syscalls))
595 return;
596
597 sys_data = syscall_nr_to_meta(syscall_nr);
598 if (!sys_data)
599 return;
600
601 head = this_cpu_ptr(sys_data->enter_event->perf_events);
602 valid_prog_array = bpf_prog_array_valid(sys_data->enter_event);
603 if (!valid_prog_array && hlist_empty(head))
604 return;
605
606 /* get the size after alignment with the u32 buffer size field */
607 size = sizeof(unsigned long) * sys_data->nb_args + sizeof(*rec);
608 size = ALIGN(size + sizeof(u32), sizeof(u64));
609 size -= sizeof(u32);
610
611 rec = perf_trace_buf_alloc(size, NULL, &rctx);
612 if (!rec)
613 return;
614
615 rec->nr = syscall_nr;
616 syscall_get_arguments(current, regs, 0, sys_data->nb_args,
617 (unsigned long *)&rec->args);
618
619 if ((valid_prog_array &&
620 !perf_call_bpf_enter(sys_data->enter_event, regs, sys_data, rec)) ||
621 hlist_empty(head)) {
622 perf_swevent_put_recursion_context(rctx);
623 return;
624 }
625
626 perf_trace_buf_submit(rec, size, rctx,
627 sys_data->enter_event->event.type, 1, regs,
628 head, NULL);
629}
630
631static int perf_sysenter_enable(struct trace_event_call *call)
632{
633 int ret = 0;
634 int num;
635
636 num = ((struct syscall_metadata *)call->data)->syscall_nr;
637
638 mutex_lock(&syscall_trace_lock);
639 if (!sys_perf_refcount_enter)
640 ret = register_trace_sys_enter(perf_syscall_enter, NULL);
641 if (ret) {
642 pr_info("event trace: Could not activate syscall entry trace point");
643 } else {
644 set_bit(num, enabled_perf_enter_syscalls);
645 sys_perf_refcount_enter++;
646 }
647 mutex_unlock(&syscall_trace_lock);
648 return ret;
649}
650
651static void perf_sysenter_disable(struct trace_event_call *call)
652{
653 int num;
654
655 num = ((struct syscall_metadata *)call->data)->syscall_nr;
656
657 mutex_lock(&syscall_trace_lock);
658 sys_perf_refcount_enter--;
659 clear_bit(num, enabled_perf_enter_syscalls);
660 if (!sys_perf_refcount_enter)
661 unregister_trace_sys_enter(perf_syscall_enter, NULL);
662 mutex_unlock(&syscall_trace_lock);
663}
664
665static int perf_call_bpf_exit(struct trace_event_call *call, struct pt_regs *regs,
666 struct syscall_trace_exit *rec)
667{
668 struct syscall_tp_t {
669 unsigned long long regs;
670 unsigned long syscall_nr;
671 unsigned long ret;
672 } param;
673
674 *(struct pt_regs **)¶m = regs;
675 param.syscall_nr = rec->nr;
676 param.ret = rec->ret;
677 return trace_call_bpf(call, ¶m);
678}
679
680static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
681{
682 struct syscall_metadata *sys_data;
683 struct syscall_trace_exit *rec;
684 struct hlist_head *head;
685 bool valid_prog_array;
686 int syscall_nr;
687 int rctx;
688 int size;
689
690 syscall_nr = trace_get_syscall_nr(current, regs);
691 if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
692 return;
693 if (!test_bit(syscall_nr, enabled_perf_exit_syscalls))
694 return;
695
696 sys_data = syscall_nr_to_meta(syscall_nr);
697 if (!sys_data)
698 return;
699
700 head = this_cpu_ptr(sys_data->exit_event->perf_events);
701 valid_prog_array = bpf_prog_array_valid(sys_data->exit_event);
702 if (!valid_prog_array && hlist_empty(head))
703 return;
704
705 /* We can probably do that at build time */
706 size = ALIGN(sizeof(*rec) + sizeof(u32), sizeof(u64));
707 size -= sizeof(u32);
708
709 rec = perf_trace_buf_alloc(size, NULL, &rctx);
710 if (!rec)
711 return;
712
713 rec->nr = syscall_nr;
714 rec->ret = syscall_get_return_value(current, regs);
715
716 if ((valid_prog_array &&
717 !perf_call_bpf_exit(sys_data->exit_event, regs, rec)) ||
718 hlist_empty(head)) {
719 perf_swevent_put_recursion_context(rctx);
720 return;
721 }
722
723 perf_trace_buf_submit(rec, size, rctx, sys_data->exit_event->event.type,
724 1, regs, head, NULL);
725}
726
727static int perf_sysexit_enable(struct trace_event_call *call)
728{
729 int ret = 0;
730 int num;
731
732 num = ((struct syscall_metadata *)call->data)->syscall_nr;
733
734 mutex_lock(&syscall_trace_lock);
735 if (!sys_perf_refcount_exit)
736 ret = register_trace_sys_exit(perf_syscall_exit, NULL);
737 if (ret) {
738 pr_info("event trace: Could not activate syscall exit trace point");
739 } else {
740 set_bit(num, enabled_perf_exit_syscalls);
741 sys_perf_refcount_exit++;
742 }
743 mutex_unlock(&syscall_trace_lock);
744 return ret;
745}
746
747static void perf_sysexit_disable(struct trace_event_call *call)
748{
749 int num;
750
751 num = ((struct syscall_metadata *)call->data)->syscall_nr;
752
753 mutex_lock(&syscall_trace_lock);
754 sys_perf_refcount_exit--;
755 clear_bit(num, enabled_perf_exit_syscalls);
756 if (!sys_perf_refcount_exit)
757 unregister_trace_sys_exit(perf_syscall_exit, NULL);
758 mutex_unlock(&syscall_trace_lock);
759}
760
761#endif /* CONFIG_PERF_EVENTS */
762
763static int syscall_enter_register(struct trace_event_call *event,
764 enum trace_reg type, void *data)
765{
766 struct trace_event_file *file = data;
767
768 switch (type) {
769 case TRACE_REG_REGISTER:
770 return reg_event_syscall_enter(file, event);
771 case TRACE_REG_UNREGISTER:
772 unreg_event_syscall_enter(file, event);
773 return 0;
774
775#ifdef CONFIG_PERF_EVENTS
776 case TRACE_REG_PERF_REGISTER:
777 return perf_sysenter_enable(event);
778 case TRACE_REG_PERF_UNREGISTER:
779 perf_sysenter_disable(event);
780 return 0;
781 case TRACE_REG_PERF_OPEN:
782 case TRACE_REG_PERF_CLOSE:
783 case TRACE_REG_PERF_ADD:
784 case TRACE_REG_PERF_DEL:
785 return 0;
786#endif
787 }
788 return 0;
789}
790
791static int syscall_exit_register(struct trace_event_call *event,
792 enum trace_reg type, void *data)
793{
794 struct trace_event_file *file = data;
795
796 switch (type) {
797 case TRACE_REG_REGISTER:
798 return reg_event_syscall_exit(file, event);
799 case TRACE_REG_UNREGISTER:
800 unreg_event_syscall_exit(file, event);
801 return 0;
802
803#ifdef CONFIG_PERF_EVENTS
804 case TRACE_REG_PERF_REGISTER:
805 return perf_sysexit_enable(event);
806 case TRACE_REG_PERF_UNREGISTER:
807 perf_sysexit_disable(event);
808 return 0;
809 case TRACE_REG_PERF_OPEN:
810 case TRACE_REG_PERF_CLOSE:
811 case TRACE_REG_PERF_ADD:
812 case TRACE_REG_PERF_DEL:
813 return 0;
814#endif
815 }
816 return 0;
817}