projects / deliverable / linux.git / blob
? search:


7c7cfe95a8538f0cbf049baf21e514264c61ff6e
[deliverable/linux.git] / kernel / trace / trace_syscalls.c
1 #include <trace/syscall.h>
2 #include <trace/events/syscalls.h>
3 #include <linux/slab.h>
4 #include <linux/kernel.h>
5 #include <linux/ftrace.h>
6 #include <linux/perf_event.h>
7 #include <asm/syscall.h>
8
9 #include "trace_output.h"
10 #include "trace.h"
11
12 static DEFINE_MUTEX(syscall_trace_lock);
13 static int sys_refcount_enter;
14 static int sys_refcount_exit;
15 static DECLARE_BITMAP(enabled_enter_syscalls, NR_syscalls);
16 static DECLARE_BITMAP(enabled_exit_syscalls, NR_syscalls);
17
18 static int syscall_enter_register(struct ftrace_event_call *event,
19 enum trace_reg type);
20 static int syscall_exit_register(struct ftrace_event_call *event,
21 enum trace_reg type);
22
23 static int syscall_enter_define_fields(struct ftrace_event_call *call);
24 static int syscall_exit_define_fields(struct ftrace_event_call *call);
25
26 static struct list_head *
27 syscall_get_enter_fields(struct ftrace_event_call *call)
28 {
29 struct syscall_metadata *entry = call->data;
30
31 return &entry->enter_fields;
32 }
33
34 static struct list_head *
35 syscall_get_exit_fields(struct ftrace_event_call *call)
36 {
37 struct syscall_metadata *entry = call->data;
38
39 return &entry->exit_fields;
40 }
41
42 struct trace_event_functions enter_syscall_print_funcs = {
43 .trace = print_syscall_enter,
44 };
45
46 struct trace_event_functions exit_syscall_print_funcs = {
47 .trace = print_syscall_exit,
48 };
49
50 struct ftrace_event_class event_class_syscall_enter = {
51 .system = "syscalls",
52 .reg = syscall_enter_register,
53 .define_fields = syscall_enter_define_fields,
54 .get_fields = syscall_get_enter_fields,
55 .raw_init = init_syscall_trace,
56 };
57
58 struct ftrace_event_class event_class_syscall_exit = {
59 .system = "syscalls",
60 .reg = syscall_exit_register,
61 .define_fields = syscall_exit_define_fields,
62 .get_fields = syscall_get_exit_fields,
63 .raw_init = init_syscall_trace,
64 };
65
66 extern unsigned long __start_syscalls_metadata[];
67 extern unsigned long __stop_syscalls_metadata[];
68
69 static struct syscall_metadata **syscalls_metadata;
70
71 static struct syscall_metadata *find_syscall_meta(unsigned long syscall)
72 {
73 struct syscall_metadata *start;
74 struct syscall_metadata *stop;
75 char str[KSYM_SYMBOL_LEN];
76
77
78 start = (struct syscall_metadata *)__start_syscalls_metadata;
79 stop = (struct syscall_metadata *)__stop_syscalls_metadata;
80 kallsyms_lookup(syscall, NULL, NULL, NULL, str);
81
82 for ( ; start < stop; start++) {
83 /*
84 * Only compare after the "sys" prefix. Archs that use
85 * syscall wrappers may have syscalls symbols aliases prefixed
86 * with "SyS" instead of "sys", leading to an unwanted
87 * mismatch.
88 */
89 if (start->name && !strcmp(start->name + 3, str + 3))
90 return start;
91 }
92 return NULL;
93 }
94
95 static struct syscall_metadata *syscall_nr_to_meta(int nr)
96 {
97 if (!syscalls_metadata || nr >= NR_syscalls || nr < 0)
98 return NULL;
99
100 return syscalls_metadata[nr];
101 }
102
103 enum print_line_t
104 print_syscall_enter(struct trace_iterator *iter, int flags,
105 struct trace_event *event)
106 {
107 struct trace_seq *s = &iter->seq;
108 struct trace_entry *ent = iter->ent;
109 struct syscall_trace_enter *trace;
110 struct syscall_metadata *entry;
111 int i, ret, syscall;
112
113 trace = (typeof(trace))ent;
114 syscall = trace->nr;
115 entry = syscall_nr_to_meta(syscall);
116
117 if (!entry)
118 goto end;
119
120 if (entry->enter_event->id != ent->type) {
121 WARN_ON_ONCE(1);
122 goto end;
123 }
124
125 ret = trace_seq_printf(s, "%s(", entry->name);
126 if (!ret)
127 return TRACE_TYPE_PARTIAL_LINE;
128
129 for (i = 0; i < entry->nb_args; i++) {
130 /* parameter types */
131 if (trace_flags & TRACE_ITER_VERBOSE) {
132 ret = trace_seq_printf(s, "%s ", entry->types[i]);
133 if (!ret)
134 return TRACE_TYPE_PARTIAL_LINE;
135 }
136 /* parameter values */
137 ret = trace_seq_printf(s, "%s: %lx%s", entry->args[i],
138 trace->args[i],
139 i == entry->nb_args - 1 ? "" : ", ");
140 if (!ret)
141 return TRACE_TYPE_PARTIAL_LINE;
142 }
143
144 ret = trace_seq_putc(s, ')');
145 if (!ret)
146 return TRACE_TYPE_PARTIAL_LINE;
147
148 end:
149 ret = trace_seq_putc(s, '\n');
150 if (!ret)
151 return TRACE_TYPE_PARTIAL_LINE;
152
153 return TRACE_TYPE_HANDLED;
154 }
155
156 enum print_line_t
157 print_syscall_exit(struct trace_iterator *iter, int flags,
158 struct trace_event *event)
159 {
160 struct trace_seq *s = &iter->seq;
161 struct trace_entry *ent = iter->ent;
162 struct syscall_trace_exit *trace;
163 int syscall;
164 struct syscall_metadata *entry;
165 int ret;
166
167 trace = (typeof(trace))ent;
168 syscall = trace->nr;
169 entry = syscall_nr_to_meta(syscall);
170
171 if (!entry) {
172 trace_seq_printf(s, "\n");
173 return TRACE_TYPE_HANDLED;
174 }
175
176 if (entry->exit_event->id != ent->type) {
177 WARN_ON_ONCE(1);
178 return TRACE_TYPE_UNHANDLED;
179 }
180
181 ret = trace_seq_printf(s, "%s -> 0x%lx\n", entry->name,
182 trace->ret);
183 if (!ret)
184 return TRACE_TYPE_PARTIAL_LINE;
185
186 return TRACE_TYPE_HANDLED;
187 }
188
189 extern char *__bad_type_size(void);
190
191 #define SYSCALL_FIELD(type, name) \
192 sizeof(type) != sizeof(trace.name) ? \
193 __bad_type_size() : \
194 #type, #name, offsetof(typeof(trace), name), \
195 sizeof(trace.name), is_signed_type(type)
196
197 static
198 int __set_enter_print_fmt(struct syscall_metadata *entry, char *buf, int len)
199 {
200 int i;
201 int pos = 0;
202
203 /* When len=0, we just calculate the needed length */
204 #define LEN_OR_ZERO (len ? len - pos : 0)
205
206 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
207 for (i = 0; i < entry->nb_args; i++) {
208 pos += snprintf(buf + pos, LEN_OR_ZERO, "%s: 0x%%0%zulx%s",
209 entry->args[i], sizeof(unsigned long),
210 i == entry->nb_args - 1 ? "" : ", ");
211 }
212 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
213
214 for (i = 0; i < entry->nb_args; i++) {
215 pos += snprintf(buf + pos, LEN_OR_ZERO,
216 ", ((unsigned long)(REC->%s))", entry->args[i]);
217 }
218
219 #undef LEN_OR_ZERO
220
221 /* return the length of print_fmt */
222 return pos;
223 }
224
225 static int set_syscall_print_fmt(struct ftrace_event_call *call)
226 {
227 char *print_fmt;
228 int len;
229 struct syscall_metadata *entry = call->data;
230
231 if (entry->enter_event != call) {
232 call->print_fmt = "\"0x%lx\", REC->ret";
233 return 0;
234 }
235
236 /* First: called with 0 length to calculate the needed length */
237 len = __set_enter_print_fmt(entry, NULL, 0);
238
239 print_fmt = kmalloc(len + 1, GFP_KERNEL);
240 if (!print_fmt)
241 return -ENOMEM;
242
243 /* Second: actually write the @print_fmt */
244 __set_enter_print_fmt(entry, print_fmt, len + 1);
245 call->print_fmt = print_fmt;
246
247 return 0;
248 }
249
250 static void free_syscall_print_fmt(struct ftrace_event_call *call)
251 {
252 struct syscall_metadata *entry = call->data;
253
254 if (entry->enter_event == call)
255 kfree(call->print_fmt);
256 }
257
258 static int syscall_enter_define_fields(struct ftrace_event_call *call)
259 {
260 struct syscall_trace_enter trace;
261 struct syscall_metadata *meta = call->data;
262 int ret;
263 int i;
264 int offset = offsetof(typeof(trace), args);
265
266 ret = trace_define_field(call, SYSCALL_FIELD(int, nr), FILTER_OTHER);
267 if (ret)
268 return ret;
269
270 for (i = 0; i < meta->nb_args; i++) {
271 ret = trace_define_field(call, meta->types[i],
272 meta->args[i], offset,
273 sizeof(unsigned long), 0,
274 FILTER_OTHER);
275 offset += sizeof(unsigned long);
276 }
277
278 return ret;
279 }
280
281 static int syscall_exit_define_fields(struct ftrace_event_call *call)
282 {
283 struct syscall_trace_exit trace;
284 int ret;
285
286 ret = trace_define_field(call, SYSCALL_FIELD(int, nr), FILTER_OTHER);
287 if (ret)
288 return ret;
289
290 ret = trace_define_field(call, SYSCALL_FIELD(long, ret),
291 FILTER_OTHER);
292
293 return ret;
294 }
295
296 void ftrace_syscall_enter(void *ignore, struct pt_regs *regs, long id)
297 {
298 struct syscall_trace_enter *entry;
299 struct syscall_metadata *sys_data;
300 struct ring_buffer_event *event;
301 struct ring_buffer *buffer;
302 int size;
303 int syscall_nr;
304
305 syscall_nr = syscall_get_nr(current, regs);
306 if (syscall_nr < 0)
307 return;
308 if (!test_bit(syscall_nr, enabled_enter_syscalls))
309 return;
310
311 sys_data = syscall_nr_to_meta(syscall_nr);
312 if (!sys_data)
313 return;
314
315 size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args;
316
317 event = trace_current_buffer_lock_reserve(&buffer,
318 sys_data->enter_event->id, size, 0, 0);
319 if (!event)
320 return;
321
322 entry = ring_buffer_event_data(event);
323 entry->nr = syscall_nr;
324 syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args);
325
326 if (!filter_current_check_discard(buffer, sys_data->enter_event,
327 entry, event))
328 trace_current_buffer_unlock_commit(buffer, event, 0, 0);
329 }
330
331 void ftrace_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
332 {
333 struct syscall_trace_exit *entry;
334 struct syscall_metadata *sys_data;
335 struct ring_buffer_event *event;
336 struct ring_buffer *buffer;
337 int syscall_nr;
338
339 syscall_nr = syscall_get_nr(current, regs);
340 if (syscall_nr < 0)
341 return;
342 if (!test_bit(syscall_nr, enabled_exit_syscalls))
343 return;
344
345 sys_data = syscall_nr_to_meta(syscall_nr);
346 if (!sys_data)
347 return;
348
349 event = trace_current_buffer_lock_reserve(&buffer,
350 sys_data->exit_event->id, sizeof(*entry), 0, 0);
351 if (!event)
352 return;
353
354 entry = ring_buffer_event_data(event);
355 entry->nr = syscall_nr;
356 entry->ret = syscall_get_return_value(current, regs);
357
358 if (!filter_current_check_discard(buffer, sys_data->exit_event,
359 entry, event))
360 trace_current_buffer_unlock_commit(buffer, event, 0, 0);
361 }
362
363 int reg_event_syscall_enter(struct ftrace_event_call *call)
364 {
365 int ret = 0;
366 int num;
367
368 num = ((struct syscall_metadata *)call->data)->syscall_nr;
369 if (num < 0 || num >= NR_syscalls)
370 return -ENOSYS;
371 mutex_lock(&syscall_trace_lock);
372 if (!sys_refcount_enter)
373 ret = register_trace_sys_enter(ftrace_syscall_enter, NULL);
374 if (!ret) {
375 set_bit(num, enabled_enter_syscalls);
376 sys_refcount_enter++;
377 }
378 mutex_unlock(&syscall_trace_lock);
379 return ret;
380 }
381
382 void unreg_event_syscall_enter(struct ftrace_event_call *call)
383 {
384 int num;
385
386 num = ((struct syscall_metadata *)call->data)->syscall_nr;
387 if (num < 0 || num >= NR_syscalls)
388 return;
389 mutex_lock(&syscall_trace_lock);
390 sys_refcount_enter--;
391 clear_bit(num, enabled_enter_syscalls);
392 if (!sys_refcount_enter)
393 unregister_trace_sys_enter(ftrace_syscall_enter, NULL);
394 mutex_unlock(&syscall_trace_lock);
395 }
396
397 int reg_event_syscall_exit(struct ftrace_event_call *call)
398 {
399 int ret = 0;
400 int num;
401
402 num = ((struct syscall_metadata *)call->data)->syscall_nr;
403 if (num < 0 || num >= NR_syscalls)
404 return -ENOSYS;
405 mutex_lock(&syscall_trace_lock);
406 if (!sys_refcount_exit)
407 ret = register_trace_sys_exit(ftrace_syscall_exit, NULL);
408 if (!ret) {
409 set_bit(num, enabled_exit_syscalls);
410 sys_refcount_exit++;
411 }
412 mutex_unlock(&syscall_trace_lock);
413 return ret;
414 }
415
416 void unreg_event_syscall_exit(struct ftrace_event_call *call)
417 {
418 int num;
419
420 num = ((struct syscall_metadata *)call->data)->syscall_nr;
421 if (num < 0 || num >= NR_syscalls)
422 return;
423 mutex_lock(&syscall_trace_lock);
424 sys_refcount_exit--;
425 clear_bit(num, enabled_exit_syscalls);
426 if (!sys_refcount_exit)
427 unregister_trace_sys_exit(ftrace_syscall_exit, NULL);
428 mutex_unlock(&syscall_trace_lock);
429 }
430
431 int init_syscall_trace(struct ftrace_event_call *call)
432 {
433 int id;
434
435 if (set_syscall_print_fmt(call) < 0)
436 return -ENOMEM;
437
438 id = trace_event_raw_init(call);
439
440 if (id < 0) {
441 free_syscall_print_fmt(call);
442 return id;
443 }
444
445 return id;
446 }
447
448 unsigned long __init arch_syscall_addr(int nr)
449 {
450 return (unsigned long)sys_call_table[nr];
451 }
452
453 int __init init_ftrace_syscalls(void)
454 {
455 struct syscall_metadata *meta;
456 unsigned long addr;
457 int i;
458
459 syscalls_metadata = kzalloc(sizeof(*syscalls_metadata) *
460 NR_syscalls, GFP_KERNEL);
461 if (!syscalls_metadata) {
462 WARN_ON(1);
463 return -ENOMEM;
464 }
465
466 for (i = 0; i < NR_syscalls; i++) {
467 addr = arch_syscall_addr(i);
468 meta = find_syscall_meta(addr);
469 if (!meta)
470 continue;
471
472 meta->syscall_nr = i;
473 syscalls_metadata[i] = meta;
474 }
475
476 return 0;
477 }
478 core_initcall(init_ftrace_syscalls);
479
480 #ifdef CONFIG_PERF_EVENTS
481
482 static DECLARE_BITMAP(enabled_perf_enter_syscalls, NR_syscalls);
483 static DECLARE_BITMAP(enabled_perf_exit_syscalls, NR_syscalls);
484 static int sys_perf_refcount_enter;
485 static int sys_perf_refcount_exit;
486
487 static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
488 {
489 struct syscall_metadata *sys_data;
490 struct syscall_trace_enter *rec;
491 unsigned long flags;
492 int syscall_nr;
493 int rctx;
494 int size;
495
496 syscall_nr = syscall_get_nr(current, regs);
497 if (!test_bit(syscall_nr, enabled_perf_enter_syscalls))
498 return;
499
500 sys_data = syscall_nr_to_meta(syscall_nr);
501 if (!sys_data)
502 return;
503
504 /* get the size after alignment with the u32 buffer size field */
505 size = sizeof(unsigned long) * sys_data->nb_args + sizeof(*rec);
506 size = ALIGN(size + sizeof(u32), sizeof(u64));
507 size -= sizeof(u32);
508
509 if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
510 "perf buffer not large enough"))
511 return;
512
513 rec = (struct syscall_trace_enter *)perf_trace_buf_prepare(size,
514 sys_data->enter_event->id, &rctx, &flags);
515 if (!rec)
516 return;
517
518 rec->nr = syscall_nr;
519 syscall_get_arguments(current, regs, 0, sys_data->nb_args,
520 (unsigned long *)&rec->args);
521 perf_trace_buf_submit(rec, size, rctx, 0, 1, flags, regs);
522 }
523
524 int perf_sysenter_enable(struct ftrace_event_call *call)
525 {
526 int ret = 0;
527 int num;
528
529 num = ((struct syscall_metadata *)call->data)->syscall_nr;
530
531 mutex_lock(&syscall_trace_lock);
532 if (!sys_perf_refcount_enter)
533 ret = register_trace_sys_enter(perf_syscall_enter, NULL);
534 if (ret) {
535 pr_info("event trace: Could not activate"
536 "syscall entry trace point");
537 } else {
538 set_bit(num, enabled_perf_enter_syscalls);
539 sys_perf_refcount_enter++;
540 }
541 mutex_unlock(&syscall_trace_lock);
542 return ret;
543 }
544
545 void perf_sysenter_disable(struct ftrace_event_call *call)
546 {
547 int num;
548
549 num = ((struct syscall_metadata *)call->data)->syscall_nr;
550
551 mutex_lock(&syscall_trace_lock);
552 sys_perf_refcount_enter--;
553 clear_bit(num, enabled_perf_enter_syscalls);
554 if (!sys_perf_refcount_enter)
555 unregister_trace_sys_enter(perf_syscall_enter, NULL);
556 mutex_unlock(&syscall_trace_lock);
557 }
558
559 static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
560 {
561 struct syscall_metadata *sys_data;
562 struct syscall_trace_exit *rec;
563 unsigned long flags;
564 int syscall_nr;
565 int rctx;
566 int size;
567
568 syscall_nr = syscall_get_nr(current, regs);
569 if (!test_bit(syscall_nr, enabled_perf_exit_syscalls))
570 return;
571
572 sys_data = syscall_nr_to_meta(syscall_nr);
573 if (!sys_data)
574 return;
575
576 /* We can probably do that at build time */
577 size = ALIGN(sizeof(*rec) + sizeof(u32), sizeof(u64));
578 size -= sizeof(u32);
579
580 /*
581 * Impossible, but be paranoid with the future
582 * How to put this check outside runtime?
583 */
584 if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
585 "exit event has grown above perf buffer size"))
586 return;
587
588 rec = (struct syscall_trace_exit *)perf_trace_buf_prepare(size,
589 sys_data->exit_event->id, &rctx, &flags);
590 if (!rec)
591 return;
592
593 rec->nr = syscall_nr;
594 rec->ret = syscall_get_return_value(current, regs);
595
596 perf_trace_buf_submit(rec, size, rctx, 0, 1, flags, regs);
597 }
598
599 int perf_sysexit_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_exit)
608 ret = register_trace_sys_exit(perf_syscall_exit, NULL);
609 if (ret) {
610 pr_info("event trace: Could not activate"
611 "syscall exit trace point");
612 } else {
613 set_bit(num, enabled_perf_exit_syscalls);
614 sys_perf_refcount_exit++;
615 }
616 mutex_unlock(&syscall_trace_lock);
617 return ret;
618 }
619
620 void perf_sysexit_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_exit--;
628 clear_bit(num, enabled_perf_exit_syscalls);
629 if (!sys_perf_refcount_exit)
630 unregister_trace_sys_exit(perf_syscall_exit, NULL);
631 mutex_unlock(&syscall_trace_lock);
632 }
633
634 #endif /* CONFIG_PERF_EVENTS */
635
636 static int syscall_enter_register(struct ftrace_event_call *event,
637 enum trace_reg type)
638 {
639 switch (type) {
640 case TRACE_REG_REGISTER:
641 return reg_event_syscall_enter(event);
642 case TRACE_REG_UNREGISTER:
643 unreg_event_syscall_enter(event);
644 return 0;
645
646 #ifdef CONFIG_PERF_EVENTS
647 case TRACE_REG_PERF_REGISTER:
648 return perf_sysenter_enable(event);
649 case TRACE_REG_PERF_UNREGISTER:
650 perf_sysenter_disable(event);
651 return 0;
652 #endif
653 }
654 return 0;
655 }
656
657 static int syscall_exit_register(struct ftrace_event_call *event,
658 enum trace_reg type)
659 {
660 switch (type) {
661 case TRACE_REG_REGISTER:
662 return reg_event_syscall_exit(event);
663 case TRACE_REG_UNREGISTER:
664 unreg_event_syscall_exit(event);
665 return 0;
666
667 #ifdef CONFIG_PERF_EVENTS
668 case TRACE_REG_PERF_REGISTER:
669 return perf_sysexit_enable(event);
670 case TRACE_REG_PERF_UNREGISTER:
671 perf_sysexit_disable(event);
672 return 0;
673 #endif
674 }
675 return 0;
676 }
Linux kernel - Deliverables
This page took 0.043397 seconds and 4 git commands to generate.