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