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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 trace_event_call *event,
17 enum trace_reg type, void *data);
18static int syscall_exit_register(struct trace_event_call *event,
19 enum trace_reg type, void *data);
20
21static struct list_head *
22syscall_get_enter_fields(struct trace_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
109const char *get_syscall_name(int syscall)
110{
111 struct syscall_metadata *entry;
112
113 entry = syscall_nr_to_meta(syscall);
114 if (!entry)
115 return NULL;
116
117 return entry->name;
118}
119
120static enum print_line_t
121print_syscall_enter(struct trace_iterator *iter, int flags,
122 struct trace_event *event)
123{
124 struct trace_array *tr = iter->tr;
125 struct trace_seq *s = &iter->seq;
126 struct trace_entry *ent = iter->ent;
127 struct syscall_trace_enter *trace;
128 struct syscall_metadata *entry;
129 int i, syscall;
130
131 trace = (typeof(trace))ent;
132 syscall = trace->nr;
133 entry = syscall_nr_to_meta(syscall);
134
135 if (!entry)
136 goto end;
137
138 if (entry->enter_event->event.type != ent->type) {
139 WARN_ON_ONCE(1);
140 goto end;
141 }
142
143 trace_seq_printf(s, "%s(", entry->name);
144
145 for (i = 0; i < entry->nb_args; i++) {
146
147 if (trace_seq_has_overflowed(s))
148 goto end;
149
150 /* parameter types */
151 if (tr->trace_flags & TRACE_ITER_VERBOSE)
152 trace_seq_printf(s, "%s ", entry->types[i]);
153
154 /* parameter values */
155 trace_seq_printf(s, "%s: %lx%s", entry->args[i],
156 trace->args[i],
157 i == entry->nb_args - 1 ? "" : ", ");
158 }
159
160 trace_seq_putc(s, ')');
161end:
162 trace_seq_putc(s, '\n');
163
164 return trace_handle_return(s);
165}
166
167static enum print_line_t
168print_syscall_exit(struct trace_iterator *iter, int flags,
169 struct trace_event *event)
170{
171 struct trace_seq *s = &iter->seq;
172 struct trace_entry *ent = iter->ent;
173 struct syscall_trace_exit *trace;
174 int syscall;
175 struct syscall_metadata *entry;
176
177 trace = (typeof(trace))ent;
178 syscall = trace->nr;
179 entry = syscall_nr_to_meta(syscall);
180
181 if (!entry) {
182 trace_seq_putc(s, '\n');
183 goto out;
184 }
185
186 if (entry->exit_event->event.type != ent->type) {
187 WARN_ON_ONCE(1);
188 return TRACE_TYPE_UNHANDLED;
189 }
190
191 trace_seq_printf(s, "%s -> 0x%lx\n", entry->name,
192 trace->ret);
193
194 out:
195 return trace_handle_return(s);
196}
197
198extern char *__bad_type_size(void);
199
200#define SYSCALL_FIELD(type, field, name) \
201 sizeof(type) != sizeof(trace.field) ? \
202 __bad_type_size() : \
203 #type, #name, offsetof(typeof(trace), field), \
204 sizeof(trace.field), is_signed_type(type)
205
206static int __init
207__set_enter_print_fmt(struct syscall_metadata *entry, char *buf, int len)
208{
209 int i;
210 int pos = 0;
211
212 /* When len=0, we just calculate the needed length */
213#define LEN_OR_ZERO (len ? len - pos : 0)
214
215 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
216 for (i = 0; i < entry->nb_args; i++) {
217 pos += snprintf(buf + pos, LEN_OR_ZERO, "%s: 0x%%0%zulx%s",
218 entry->args[i], sizeof(unsigned long),
219 i == entry->nb_args - 1 ? "" : ", ");
220 }
221 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
222
223 for (i = 0; i < entry->nb_args; i++) {
224 pos += snprintf(buf + pos, LEN_OR_ZERO,
225 ", ((unsigned long)(REC->%s))", entry->args[i]);
226 }
227
228#undef LEN_OR_ZERO
229
230 /* return the length of print_fmt */
231 return pos;
232}
233
234static int __init set_syscall_print_fmt(struct trace_event_call *call)
235{
236 char *print_fmt;
237 int len;
238 struct syscall_metadata *entry = call->data;
239
240 if (entry->enter_event != call) {
241 call->print_fmt = "\"0x%lx\", REC->ret";
242 return 0;
243 }
244
245 /* First: called with 0 length to calculate the needed length */
246 len = __set_enter_print_fmt(entry, NULL, 0);
247
248 print_fmt = kmalloc(len + 1, GFP_KERNEL);
249 if (!print_fmt)
250 return -ENOMEM;
251
252 /* Second: actually write the @print_fmt */
253 __set_enter_print_fmt(entry, print_fmt, len + 1);
254 call->print_fmt = print_fmt;
255
256 return 0;
257}
258
259static void __init free_syscall_print_fmt(struct trace_event_call *call)
260{
261 struct syscall_metadata *entry = call->data;
262
263 if (entry->enter_event == call)
264 kfree(call->print_fmt);
265}
266
267static int __init syscall_enter_define_fields(struct trace_event_call *call)
268{
269 struct syscall_trace_enter trace;
270 struct syscall_metadata *meta = call->data;
271 int ret;
272 int i;
273 int offset = offsetof(typeof(trace), args);
274
275 ret = trace_define_field(call, SYSCALL_FIELD(int, nr, __syscall_nr),
276 FILTER_OTHER);
277 if (ret)
278 return ret;
279
280 for (i = 0; i < meta->nb_args; i++) {
281 ret = trace_define_field(call, meta->types[i],
282 meta->args[i], offset,
283 sizeof(unsigned long), 0,
284 FILTER_OTHER);
285 offset += sizeof(unsigned long);
286 }
287
288 return ret;
289}
290
291static int __init syscall_exit_define_fields(struct trace_event_call *call)
292{
293 struct syscall_trace_exit trace;
294 int ret;
295
296 ret = trace_define_field(call, SYSCALL_FIELD(int, nr, __syscall_nr),
297 FILTER_OTHER);
298 if (ret)
299 return ret;
300
301 ret = trace_define_field(call, SYSCALL_FIELD(long, ret, ret),
302 FILTER_OTHER);
303
304 return ret;
305}
306
307static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
308{
309 struct trace_array *tr = data;
310 struct trace_event_file *trace_file;
311 struct syscall_trace_enter *entry;
312 struct syscall_metadata *sys_data;
313 struct ring_buffer_event *event;
314 struct ring_buffer *buffer;
315 unsigned long irq_flags;
316 int pc;
317 int syscall_nr;
318 int size;
319
320 syscall_nr = trace_get_syscall_nr(current, regs);
321 if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
322 return;
323
324 /* Here we're inside tp handler's rcu_read_lock_sched (__DO_TRACE) */
325 trace_file = rcu_dereference_sched(tr->enter_syscall_files[syscall_nr]);
326 if (!trace_file)
327 return;
328
329 if (trace_trigger_soft_disabled(trace_file))
330 return;
331
332 sys_data = syscall_nr_to_meta(syscall_nr);
333 if (!sys_data)
334 return;
335
336 size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args;
337
338 local_save_flags(irq_flags);
339 pc = preempt_count();
340
341 buffer = tr->trace_buffer.buffer;
342 event = trace_buffer_lock_reserve(buffer,
343 sys_data->enter_event->event.type, size, irq_flags, pc);
344 if (!event)
345 return;
346
347 entry = ring_buffer_event_data(event);
348 entry->nr = syscall_nr;
349 syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args);
350
351 event_trigger_unlock_commit(trace_file, buffer, event, entry,
352 irq_flags, pc);
353}
354
355static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret)
356{
357 struct trace_array *tr = data;
358 struct trace_event_file *trace_file;
359 struct syscall_trace_exit *entry;
360 struct syscall_metadata *sys_data;
361 struct ring_buffer_event *event;
362 struct ring_buffer *buffer;
363 unsigned long irq_flags;
364 int pc;
365 int syscall_nr;
366
367 syscall_nr = trace_get_syscall_nr(current, regs);
368 if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
369 return;
370
371 /* Here we're inside tp handler's rcu_read_lock_sched (__DO_TRACE()) */
372 trace_file = rcu_dereference_sched(tr->exit_syscall_files[syscall_nr]);
373 if (!trace_file)
374 return;
375
376 if (trace_trigger_soft_disabled(trace_file))
377 return;
378
379 sys_data = syscall_nr_to_meta(syscall_nr);
380 if (!sys_data)
381 return;
382
383 local_save_flags(irq_flags);
384 pc = preempt_count();
385
386 buffer = tr->trace_buffer.buffer;
387 event = trace_buffer_lock_reserve(buffer,
388 sys_data->exit_event->event.type, sizeof(*entry),
389 irq_flags, pc);
390 if (!event)
391 return;
392
393 entry = ring_buffer_event_data(event);
394 entry->nr = syscall_nr;
395 entry->ret = syscall_get_return_value(current, regs);
396
397 event_trigger_unlock_commit(trace_file, buffer, event, entry,
398 irq_flags, pc);
399}
400
401static int reg_event_syscall_enter(struct trace_event_file *file,
402 struct trace_event_call *call)
403{
404 struct trace_array *tr = file->tr;
405 int ret = 0;
406 int num;
407
408 num = ((struct syscall_metadata *)call->data)->syscall_nr;
409 if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
410 return -ENOSYS;
411 mutex_lock(&syscall_trace_lock);
412 if (!tr->sys_refcount_enter)
413 ret = register_trace_sys_enter(ftrace_syscall_enter, tr);
414 if (!ret) {
415 rcu_assign_pointer(tr->enter_syscall_files[num], file);
416 tr->sys_refcount_enter++;
417 }
418 mutex_unlock(&syscall_trace_lock);
419 return ret;
420}
421
422static void unreg_event_syscall_enter(struct trace_event_file *file,
423 struct trace_event_call *call)
424{
425 struct trace_array *tr = file->tr;
426 int num;
427
428 num = ((struct syscall_metadata *)call->data)->syscall_nr;
429 if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
430 return;
431 mutex_lock(&syscall_trace_lock);
432 tr->sys_refcount_enter--;
433 RCU_INIT_POINTER(tr->enter_syscall_files[num], NULL);
434 if (!tr->sys_refcount_enter)
435 unregister_trace_sys_enter(ftrace_syscall_enter, tr);
436 mutex_unlock(&syscall_trace_lock);
437}
438
439static int reg_event_syscall_exit(struct trace_event_file *file,
440 struct trace_event_call *call)
441{
442 struct trace_array *tr = file->tr;
443 int ret = 0;
444 int num;
445
446 num = ((struct syscall_metadata *)call->data)->syscall_nr;
447 if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
448 return -ENOSYS;
449 mutex_lock(&syscall_trace_lock);
450 if (!tr->sys_refcount_exit)
451 ret = register_trace_sys_exit(ftrace_syscall_exit, tr);
452 if (!ret) {
453 rcu_assign_pointer(tr->exit_syscall_files[num], file);
454 tr->sys_refcount_exit++;
455 }
456 mutex_unlock(&syscall_trace_lock);
457 return ret;
458}
459
460static void unreg_event_syscall_exit(struct trace_event_file *file,
461 struct trace_event_call *call)
462{
463 struct trace_array *tr = file->tr;
464 int num;
465
466 num = ((struct syscall_metadata *)call->data)->syscall_nr;
467 if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
468 return;
469 mutex_lock(&syscall_trace_lock);
470 tr->sys_refcount_exit--;
471 RCU_INIT_POINTER(tr->exit_syscall_files[num], NULL);
472 if (!tr->sys_refcount_exit)
473 unregister_trace_sys_exit(ftrace_syscall_exit, tr);
474 mutex_unlock(&syscall_trace_lock);
475}
476
477static int __init init_syscall_trace(struct trace_event_call *call)
478{
479 int id;
480 int num;
481
482 num = ((struct syscall_metadata *)call->data)->syscall_nr;
483 if (num < 0 || num >= NR_syscalls) {
484 pr_debug("syscall %s metadata not mapped, disabling ftrace event\n",
485 ((struct syscall_metadata *)call->data)->name);
486 return -ENOSYS;
487 }
488
489 if (set_syscall_print_fmt(call) < 0)
490 return -ENOMEM;
491
492 id = trace_event_raw_init(call);
493
494 if (id < 0) {
495 free_syscall_print_fmt(call);
496 return id;
497 }
498
499 return id;
500}
501
502struct trace_event_functions enter_syscall_print_funcs = {
503 .trace = print_syscall_enter,
504};
505
506struct trace_event_functions exit_syscall_print_funcs = {
507 .trace = print_syscall_exit,
508};
509
510struct trace_event_class __refdata event_class_syscall_enter = {
511 .system = "syscalls",
512 .reg = syscall_enter_register,
513 .define_fields = syscall_enter_define_fields,
514 .get_fields = syscall_get_enter_fields,
515 .raw_init = init_syscall_trace,
516};
517
518struct trace_event_class __refdata event_class_syscall_exit = {
519 .system = "syscalls",
520 .reg = syscall_exit_register,
521 .define_fields = syscall_exit_define_fields,
522 .fields = LIST_HEAD_INIT(event_class_syscall_exit.fields),
523 .raw_init = init_syscall_trace,
524};
525
526unsigned long __init __weak arch_syscall_addr(int nr)
527{
528 return (unsigned long)sys_call_table[nr];
529}
530
531void __init init_ftrace_syscalls(void)
532{
533 struct syscall_metadata *meta;
534 unsigned long addr;
535 int i;
536
537 syscalls_metadata = kcalloc(NR_syscalls, sizeof(*syscalls_metadata),
538 GFP_KERNEL);
539 if (!syscalls_metadata) {
540 WARN_ON(1);
541 return;
542 }
543
544 for (i = 0; i < NR_syscalls; i++) {
545 addr = arch_syscall_addr(i);
546 meta = find_syscall_meta(addr);
547 if (!meta)
548 continue;
549
550 meta->syscall_nr = i;
551 syscalls_metadata[i] = meta;
552 }
553}
554
555#ifdef CONFIG_PERF_EVENTS
556
557static DECLARE_BITMAP(enabled_perf_enter_syscalls, NR_syscalls);
558static DECLARE_BITMAP(enabled_perf_exit_syscalls, NR_syscalls);
559static int sys_perf_refcount_enter;
560static int sys_perf_refcount_exit;
561
562static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
563{
564 struct syscall_metadata *sys_data;
565 struct syscall_trace_enter *rec;
566 struct hlist_head *head;
567 int syscall_nr;
568 int rctx;
569 int size;
570
571 syscall_nr = trace_get_syscall_nr(current, regs);
572 if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
573 return;
574 if (!test_bit(syscall_nr, enabled_perf_enter_syscalls))
575 return;
576
577 sys_data = syscall_nr_to_meta(syscall_nr);
578 if (!sys_data)
579 return;
580
581 head = this_cpu_ptr(sys_data->enter_event->perf_events);
582 if (hlist_empty(head))
583 return;
584
585 /* get the size after alignment with the u32 buffer size field */
586 size = sizeof(unsigned long) * sys_data->nb_args + sizeof(*rec);
587 size = ALIGN(size + sizeof(u32), sizeof(u64));
588 size -= sizeof(u32);
589
590 rec = (struct syscall_trace_enter *)perf_trace_buf_prepare(size,
591 sys_data->enter_event->event.type, NULL, &rctx);
592 if (!rec)
593 return;
594
595 rec->nr = syscall_nr;
596 syscall_get_arguments(current, regs, 0, sys_data->nb_args,
597 (unsigned long *)&rec->args);
598 perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head, NULL);
599}
600
601static int perf_sysenter_enable(struct trace_event_call *call)
602{
603 int ret = 0;
604 int num;
605
606 num = ((struct syscall_metadata *)call->data)->syscall_nr;
607
608 mutex_lock(&syscall_trace_lock);
609 if (!sys_perf_refcount_enter)
610 ret = register_trace_sys_enter(perf_syscall_enter, NULL);
611 if (ret) {
612 pr_info("event trace: Could not activate"
613 "syscall entry trace point");
614 } else {
615 set_bit(num, enabled_perf_enter_syscalls);
616 sys_perf_refcount_enter++;
617 }
618 mutex_unlock(&syscall_trace_lock);
619 return ret;
620}
621
622static void perf_sysenter_disable(struct trace_event_call *call)
623{
624 int num;
625
626 num = ((struct syscall_metadata *)call->data)->syscall_nr;
627
628 mutex_lock(&syscall_trace_lock);
629 sys_perf_refcount_enter--;
630 clear_bit(num, enabled_perf_enter_syscalls);
631 if (!sys_perf_refcount_enter)
632 unregister_trace_sys_enter(perf_syscall_enter, NULL);
633 mutex_unlock(&syscall_trace_lock);
634}
635
636static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
637{
638 struct syscall_metadata *sys_data;
639 struct syscall_trace_exit *rec;
640 struct hlist_head *head;
641 int syscall_nr;
642 int rctx;
643 int size;
644
645 syscall_nr = trace_get_syscall_nr(current, regs);
646 if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
647 return;
648 if (!test_bit(syscall_nr, enabled_perf_exit_syscalls))
649 return;
650
651 sys_data = syscall_nr_to_meta(syscall_nr);
652 if (!sys_data)
653 return;
654
655 head = this_cpu_ptr(sys_data->exit_event->perf_events);
656 if (hlist_empty(head))
657 return;
658
659 /* We can probably do that at build time */
660 size = ALIGN(sizeof(*rec) + sizeof(u32), sizeof(u64));
661 size -= sizeof(u32);
662
663 rec = (struct syscall_trace_exit *)perf_trace_buf_prepare(size,
664 sys_data->exit_event->event.type, NULL, &rctx);
665 if (!rec)
666 return;
667
668 rec->nr = syscall_nr;
669 rec->ret = syscall_get_return_value(current, regs);
670 perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head, NULL);
671}
672
673static int perf_sysexit_enable(struct trace_event_call *call)
674{
675 int ret = 0;
676 int num;
677
678 num = ((struct syscall_metadata *)call->data)->syscall_nr;
679
680 mutex_lock(&syscall_trace_lock);
681 if (!sys_perf_refcount_exit)
682 ret = register_trace_sys_exit(perf_syscall_exit, NULL);
683 if (ret) {
684 pr_info("event trace: Could not activate"
685 "syscall exit trace point");
686 } else {
687 set_bit(num, enabled_perf_exit_syscalls);
688 sys_perf_refcount_exit++;
689 }
690 mutex_unlock(&syscall_trace_lock);
691 return ret;
692}
693
694static void perf_sysexit_disable(struct trace_event_call *call)
695{
696 int num;
697
698 num = ((struct syscall_metadata *)call->data)->syscall_nr;
699
700 mutex_lock(&syscall_trace_lock);
701 sys_perf_refcount_exit--;
702 clear_bit(num, enabled_perf_exit_syscalls);
703 if (!sys_perf_refcount_exit)
704 unregister_trace_sys_exit(perf_syscall_exit, NULL);
705 mutex_unlock(&syscall_trace_lock);
706}
707
708#endif /* CONFIG_PERF_EVENTS */
709
710static int syscall_enter_register(struct trace_event_call *event,
711 enum trace_reg type, void *data)
712{
713 struct trace_event_file *file = data;
714
715 switch (type) {
716 case TRACE_REG_REGISTER:
717 return reg_event_syscall_enter(file, event);
718 case TRACE_REG_UNREGISTER:
719 unreg_event_syscall_enter(file, event);
720 return 0;
721
722#ifdef CONFIG_PERF_EVENTS
723 case TRACE_REG_PERF_REGISTER:
724 return perf_sysenter_enable(event);
725 case TRACE_REG_PERF_UNREGISTER:
726 perf_sysenter_disable(event);
727 return 0;
728 case TRACE_REG_PERF_OPEN:
729 case TRACE_REG_PERF_CLOSE:
730 case TRACE_REG_PERF_ADD:
731 case TRACE_REG_PERF_DEL:
732 return 0;
733#endif
734 }
735 return 0;
736}
737
738static int syscall_exit_register(struct trace_event_call *event,
739 enum trace_reg type, void *data)
740{
741 struct trace_event_file *file = data;
742
743 switch (type) {
744 case TRACE_REG_REGISTER:
745 return reg_event_syscall_exit(file, event);
746 case TRACE_REG_UNREGISTER:
747 unreg_event_syscall_exit(file, event);
748 return 0;
749
750#ifdef CONFIG_PERF_EVENTS
751 case TRACE_REG_PERF_REGISTER:
752 return perf_sysexit_enable(event);
753 case TRACE_REG_PERF_UNREGISTER:
754 perf_sysexit_disable(event);
755 return 0;
756 case TRACE_REG_PERF_OPEN:
757 case TRACE_REG_PERF_CLOSE:
758 case TRACE_REG_PERF_ADD:
759 case TRACE_REG_PERF_DEL:
760 return 0;
761#endif
762 }
763 return 0;
764}
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 unsigned long args[6];
318 int pc;
319 int syscall_nr;
320 int size;
321
322 syscall_nr = trace_get_syscall_nr(current, regs);
323 if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
324 return;
325
326 /* Here we're inside tp handler's rcu_read_lock_sched (__DO_TRACE) */
327 trace_file = rcu_dereference_sched(tr->enter_syscall_files[syscall_nr]);
328 if (!trace_file)
329 return;
330
331 if (trace_trigger_soft_disabled(trace_file))
332 return;
333
334 sys_data = syscall_nr_to_meta(syscall_nr);
335 if (!sys_data)
336 return;
337
338 size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args;
339
340 local_save_flags(irq_flags);
341 pc = preempt_count();
342
343 buffer = tr->trace_buffer.buffer;
344 event = trace_buffer_lock_reserve(buffer,
345 sys_data->enter_event->event.type, size, irq_flags, pc);
346 if (!event)
347 return;
348
349 entry = ring_buffer_event_data(event);
350 entry->nr = syscall_nr;
351 syscall_get_arguments(current, regs, args);
352 memcpy(entry->args, args, sizeof(unsigned long) * sys_data->nb_args);
353
354 event_trigger_unlock_commit(trace_file, buffer, event, entry,
355 irq_flags, pc);
356}
357
358static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret)
359{
360 struct trace_array *tr = data;
361 struct trace_event_file *trace_file;
362 struct syscall_trace_exit *entry;
363 struct syscall_metadata *sys_data;
364 struct ring_buffer_event *event;
365 struct ring_buffer *buffer;
366 unsigned long irq_flags;
367 int pc;
368 int syscall_nr;
369
370 syscall_nr = trace_get_syscall_nr(current, regs);
371 if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
372 return;
373
374 /* Here we're inside tp handler's rcu_read_lock_sched (__DO_TRACE()) */
375 trace_file = rcu_dereference_sched(tr->exit_syscall_files[syscall_nr]);
376 if (!trace_file)
377 return;
378
379 if (trace_trigger_soft_disabled(trace_file))
380 return;
381
382 sys_data = syscall_nr_to_meta(syscall_nr);
383 if (!sys_data)
384 return;
385
386 local_save_flags(irq_flags);
387 pc = preempt_count();
388
389 buffer = tr->trace_buffer.buffer;
390 event = trace_buffer_lock_reserve(buffer,
391 sys_data->exit_event->event.type, sizeof(*entry),
392 irq_flags, pc);
393 if (!event)
394 return;
395
396 entry = ring_buffer_event_data(event);
397 entry->nr = syscall_nr;
398 entry->ret = syscall_get_return_value(current, regs);
399
400 event_trigger_unlock_commit(trace_file, buffer, event, entry,
401 irq_flags, pc);
402}
403
404static int reg_event_syscall_enter(struct trace_event_file *file,
405 struct trace_event_call *call)
406{
407 struct trace_array *tr = file->tr;
408 int ret = 0;
409 int num;
410
411 num = ((struct syscall_metadata *)call->data)->syscall_nr;
412 if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
413 return -ENOSYS;
414 mutex_lock(&syscall_trace_lock);
415 if (!tr->sys_refcount_enter)
416 ret = register_trace_sys_enter(ftrace_syscall_enter, tr);
417 if (!ret) {
418 rcu_assign_pointer(tr->enter_syscall_files[num], file);
419 tr->sys_refcount_enter++;
420 }
421 mutex_unlock(&syscall_trace_lock);
422 return ret;
423}
424
425static void unreg_event_syscall_enter(struct trace_event_file *file,
426 struct trace_event_call *call)
427{
428 struct trace_array *tr = file->tr;
429 int num;
430
431 num = ((struct syscall_metadata *)call->data)->syscall_nr;
432 if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
433 return;
434 mutex_lock(&syscall_trace_lock);
435 tr->sys_refcount_enter--;
436 RCU_INIT_POINTER(tr->enter_syscall_files[num], NULL);
437 if (!tr->sys_refcount_enter)
438 unregister_trace_sys_enter(ftrace_syscall_enter, tr);
439 mutex_unlock(&syscall_trace_lock);
440}
441
442static int reg_event_syscall_exit(struct trace_event_file *file,
443 struct trace_event_call *call)
444{
445 struct trace_array *tr = file->tr;
446 int ret = 0;
447 int num;
448
449 num = ((struct syscall_metadata *)call->data)->syscall_nr;
450 if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
451 return -ENOSYS;
452 mutex_lock(&syscall_trace_lock);
453 if (!tr->sys_refcount_exit)
454 ret = register_trace_sys_exit(ftrace_syscall_exit, tr);
455 if (!ret) {
456 rcu_assign_pointer(tr->exit_syscall_files[num], file);
457 tr->sys_refcount_exit++;
458 }
459 mutex_unlock(&syscall_trace_lock);
460 return ret;
461}
462
463static void unreg_event_syscall_exit(struct trace_event_file *file,
464 struct trace_event_call *call)
465{
466 struct trace_array *tr = file->tr;
467 int num;
468
469 num = ((struct syscall_metadata *)call->data)->syscall_nr;
470 if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
471 return;
472 mutex_lock(&syscall_trace_lock);
473 tr->sys_refcount_exit--;
474 RCU_INIT_POINTER(tr->exit_syscall_files[num], NULL);
475 if (!tr->sys_refcount_exit)
476 unregister_trace_sys_exit(ftrace_syscall_exit, tr);
477 mutex_unlock(&syscall_trace_lock);
478}
479
480static int __init init_syscall_trace(struct trace_event_call *call)
481{
482 int id;
483 int num;
484
485 num = ((struct syscall_metadata *)call->data)->syscall_nr;
486 if (num < 0 || num >= NR_syscalls) {
487 pr_debug("syscall %s metadata not mapped, disabling ftrace event\n",
488 ((struct syscall_metadata *)call->data)->name);
489 return -ENOSYS;
490 }
491
492 if (set_syscall_print_fmt(call) < 0)
493 return -ENOMEM;
494
495 id = trace_event_raw_init(call);
496
497 if (id < 0) {
498 free_syscall_print_fmt(call);
499 return id;
500 }
501
502 return id;
503}
504
505struct trace_event_functions enter_syscall_print_funcs = {
506 .trace = print_syscall_enter,
507};
508
509struct trace_event_functions exit_syscall_print_funcs = {
510 .trace = print_syscall_exit,
511};
512
513struct trace_event_class __refdata event_class_syscall_enter = {
514 .system = "syscalls",
515 .reg = syscall_enter_register,
516 .define_fields = syscall_enter_define_fields,
517 .get_fields = syscall_get_enter_fields,
518 .raw_init = init_syscall_trace,
519};
520
521struct trace_event_class __refdata event_class_syscall_exit = {
522 .system = "syscalls",
523 .reg = syscall_exit_register,
524 .define_fields = syscall_exit_define_fields,
525 .fields = LIST_HEAD_INIT(event_class_syscall_exit.fields),
526 .raw_init = init_syscall_trace,
527};
528
529unsigned long __init __weak arch_syscall_addr(int nr)
530{
531 return (unsigned long)sys_call_table[nr];
532}
533
534void __init init_ftrace_syscalls(void)
535{
536 struct syscall_metadata *meta;
537 unsigned long addr;
538 int i;
539
540 syscalls_metadata = kcalloc(NR_syscalls, sizeof(*syscalls_metadata),
541 GFP_KERNEL);
542 if (!syscalls_metadata) {
543 WARN_ON(1);
544 return;
545 }
546
547 for (i = 0; i < NR_syscalls; i++) {
548 addr = arch_syscall_addr(i);
549 meta = find_syscall_meta(addr);
550 if (!meta)
551 continue;
552
553 meta->syscall_nr = i;
554 syscalls_metadata[i] = meta;
555 }
556}
557
558#ifdef CONFIG_PERF_EVENTS
559
560static DECLARE_BITMAP(enabled_perf_enter_syscalls, NR_syscalls);
561static DECLARE_BITMAP(enabled_perf_exit_syscalls, NR_syscalls);
562static int sys_perf_refcount_enter;
563static int sys_perf_refcount_exit;
564
565static int perf_call_bpf_enter(struct trace_event_call *call, struct pt_regs *regs,
566 struct syscall_metadata *sys_data,
567 struct syscall_trace_enter *rec)
568{
569 struct syscall_tp_t {
570 unsigned long long regs;
571 unsigned long syscall_nr;
572 unsigned long args[SYSCALL_DEFINE_MAXARGS];
573 } param;
574 int i;
575
576 *(struct pt_regs **)¶m = regs;
577 param.syscall_nr = rec->nr;
578 for (i = 0; i < sys_data->nb_args; i++)
579 param.args[i] = rec->args[i];
580 return trace_call_bpf(call, ¶m);
581}
582
583static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
584{
585 struct syscall_metadata *sys_data;
586 struct syscall_trace_enter *rec;
587 struct hlist_head *head;
588 unsigned long args[6];
589 bool valid_prog_array;
590 int syscall_nr;
591 int rctx;
592 int size;
593
594 syscall_nr = trace_get_syscall_nr(current, regs);
595 if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
596 return;
597 if (!test_bit(syscall_nr, enabled_perf_enter_syscalls))
598 return;
599
600 sys_data = syscall_nr_to_meta(syscall_nr);
601 if (!sys_data)
602 return;
603
604 head = this_cpu_ptr(sys_data->enter_event->perf_events);
605 valid_prog_array = bpf_prog_array_valid(sys_data->enter_event);
606 if (!valid_prog_array && hlist_empty(head))
607 return;
608
609 /* get the size after alignment with the u32 buffer size field */
610 size = sizeof(unsigned long) * sys_data->nb_args + sizeof(*rec);
611 size = ALIGN(size + sizeof(u32), sizeof(u64));
612 size -= sizeof(u32);
613
614 rec = perf_trace_buf_alloc(size, NULL, &rctx);
615 if (!rec)
616 return;
617
618 rec->nr = syscall_nr;
619 syscall_get_arguments(current, regs, args);
620 memcpy(&rec->args, args, sizeof(unsigned long) * sys_data->nb_args);
621
622 if ((valid_prog_array &&
623 !perf_call_bpf_enter(sys_data->enter_event, regs, sys_data, rec)) ||
624 hlist_empty(head)) {
625 perf_swevent_put_recursion_context(rctx);
626 return;
627 }
628
629 perf_trace_buf_submit(rec, size, rctx,
630 sys_data->enter_event->event.type, 1, regs,
631 head, NULL);
632}
633
634static int perf_sysenter_enable(struct trace_event_call *call)
635{
636 int ret = 0;
637 int num;
638
639 num = ((struct syscall_metadata *)call->data)->syscall_nr;
640
641 mutex_lock(&syscall_trace_lock);
642 if (!sys_perf_refcount_enter)
643 ret = register_trace_sys_enter(perf_syscall_enter, NULL);
644 if (ret) {
645 pr_info("event trace: Could not activate syscall entry trace point");
646 } else {
647 set_bit(num, enabled_perf_enter_syscalls);
648 sys_perf_refcount_enter++;
649 }
650 mutex_unlock(&syscall_trace_lock);
651 return ret;
652}
653
654static void perf_sysenter_disable(struct trace_event_call *call)
655{
656 int num;
657
658 num = ((struct syscall_metadata *)call->data)->syscall_nr;
659
660 mutex_lock(&syscall_trace_lock);
661 sys_perf_refcount_enter--;
662 clear_bit(num, enabled_perf_enter_syscalls);
663 if (!sys_perf_refcount_enter)
664 unregister_trace_sys_enter(perf_syscall_enter, NULL);
665 mutex_unlock(&syscall_trace_lock);
666}
667
668static int perf_call_bpf_exit(struct trace_event_call *call, struct pt_regs *regs,
669 struct syscall_trace_exit *rec)
670{
671 struct syscall_tp_t {
672 unsigned long long regs;
673 unsigned long syscall_nr;
674 unsigned long ret;
675 } param;
676
677 *(struct pt_regs **)¶m = regs;
678 param.syscall_nr = rec->nr;
679 param.ret = rec->ret;
680 return trace_call_bpf(call, ¶m);
681}
682
683static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
684{
685 struct syscall_metadata *sys_data;
686 struct syscall_trace_exit *rec;
687 struct hlist_head *head;
688 bool valid_prog_array;
689 int syscall_nr;
690 int rctx;
691 int size;
692
693 syscall_nr = trace_get_syscall_nr(current, regs);
694 if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
695 return;
696 if (!test_bit(syscall_nr, enabled_perf_exit_syscalls))
697 return;
698
699 sys_data = syscall_nr_to_meta(syscall_nr);
700 if (!sys_data)
701 return;
702
703 head = this_cpu_ptr(sys_data->exit_event->perf_events);
704 valid_prog_array = bpf_prog_array_valid(sys_data->exit_event);
705 if (!valid_prog_array && hlist_empty(head))
706 return;
707
708 /* We can probably do that at build time */
709 size = ALIGN(sizeof(*rec) + sizeof(u32), sizeof(u64));
710 size -= sizeof(u32);
711
712 rec = perf_trace_buf_alloc(size, NULL, &rctx);
713 if (!rec)
714 return;
715
716 rec->nr = syscall_nr;
717 rec->ret = syscall_get_return_value(current, regs);
718
719 if ((valid_prog_array &&
720 !perf_call_bpf_exit(sys_data->exit_event, regs, rec)) ||
721 hlist_empty(head)) {
722 perf_swevent_put_recursion_context(rctx);
723 return;
724 }
725
726 perf_trace_buf_submit(rec, size, rctx, sys_data->exit_event->event.type,
727 1, regs, head, NULL);
728}
729
730static int perf_sysexit_enable(struct trace_event_call *call)
731{
732 int ret = 0;
733 int num;
734
735 num = ((struct syscall_metadata *)call->data)->syscall_nr;
736
737 mutex_lock(&syscall_trace_lock);
738 if (!sys_perf_refcount_exit)
739 ret = register_trace_sys_exit(perf_syscall_exit, NULL);
740 if (ret) {
741 pr_info("event trace: Could not activate syscall exit trace point");
742 } else {
743 set_bit(num, enabled_perf_exit_syscalls);
744 sys_perf_refcount_exit++;
745 }
746 mutex_unlock(&syscall_trace_lock);
747 return ret;
748}
749
750static void perf_sysexit_disable(struct trace_event_call *call)
751{
752 int num;
753
754 num = ((struct syscall_metadata *)call->data)->syscall_nr;
755
756 mutex_lock(&syscall_trace_lock);
757 sys_perf_refcount_exit--;
758 clear_bit(num, enabled_perf_exit_syscalls);
759 if (!sys_perf_refcount_exit)
760 unregister_trace_sys_exit(perf_syscall_exit, NULL);
761 mutex_unlock(&syscall_trace_lock);
762}
763
764#endif /* CONFIG_PERF_EVENTS */
765
766static int syscall_enter_register(struct trace_event_call *event,
767 enum trace_reg type, void *data)
768{
769 struct trace_event_file *file = data;
770
771 switch (type) {
772 case TRACE_REG_REGISTER:
773 return reg_event_syscall_enter(file, event);
774 case TRACE_REG_UNREGISTER:
775 unreg_event_syscall_enter(file, event);
776 return 0;
777
778#ifdef CONFIG_PERF_EVENTS
779 case TRACE_REG_PERF_REGISTER:
780 return perf_sysenter_enable(event);
781 case TRACE_REG_PERF_UNREGISTER:
782 perf_sysenter_disable(event);
783 return 0;
784 case TRACE_REG_PERF_OPEN:
785 case TRACE_REG_PERF_CLOSE:
786 case TRACE_REG_PERF_ADD:
787 case TRACE_REG_PERF_DEL:
788 return 0;
789#endif
790 }
791 return 0;
792}
793
794static int syscall_exit_register(struct trace_event_call *event,
795 enum trace_reg type, void *data)
796{
797 struct trace_event_file *file = data;
798
799 switch (type) {
800 case TRACE_REG_REGISTER:
801 return reg_event_syscall_exit(file, event);
802 case TRACE_REG_UNREGISTER:
803 unreg_event_syscall_exit(file, event);
804 return 0;
805
806#ifdef CONFIG_PERF_EVENTS
807 case TRACE_REG_PERF_REGISTER:
808 return perf_sysexit_enable(event);
809 case TRACE_REG_PERF_UNREGISTER:
810 perf_sysexit_disable(event);
811 return 0;
812 case TRACE_REG_PERF_OPEN:
813 case TRACE_REG_PERF_CLOSE:
814 case TRACE_REG_PERF_ADD:
815 case TRACE_REG_PERF_DEL:
816 return 0;
817#endif
818 }
819 return 0;
820}