1 #include <trace/syscall.h>
2 #include <trace/events/syscalls.h>
3 #include <linux/kernel.h>
4 #include <linux/ftrace.h>
5 #include <linux/perf_event.h>
6 #include <asm/syscall.h>
8 #include "trace_output.h"
11 static DEFINE_MUTEX(syscall_trace_lock);
12 static int sys_refcount_enter;
13 static int sys_refcount_exit;
14 static DECLARE_BITMAP(enabled_enter_syscalls, NR_syscalls);
15 static DECLARE_BITMAP(enabled_exit_syscalls, NR_syscalls);
17 extern unsigned long __start_syscalls_metadata[];
18 extern unsigned long __stop_syscalls_metadata[];
20 static struct syscall_metadata **syscalls_metadata;
22 static struct syscall_metadata *find_syscall_meta(unsigned long syscall)
24 struct syscall_metadata *start;
25 struct syscall_metadata *stop;
26 char str[KSYM_SYMBOL_LEN];
29 start = (struct syscall_metadata *)__start_syscalls_metadata;
30 stop = (struct syscall_metadata *)__stop_syscalls_metadata;
31 kallsyms_lookup(syscall, NULL, NULL, NULL, str);
33 for ( ; start < stop; start++) {
35 * Only compare after the "sys" prefix. Archs that use
36 * syscall wrappers may have syscalls symbols aliases prefixed
37 * with "SyS" instead of "sys", leading to an unwanted
40 if (start->name && !strcmp(start->name + 3, str + 3))
46 static struct syscall_metadata *syscall_nr_to_meta(int nr)
48 if (!syscalls_metadata || nr >= NR_syscalls || nr < 0)
51 return syscalls_metadata[nr];
54 int syscall_name_to_nr(char *name)
58 if (!syscalls_metadata)
61 for (i = 0; i < NR_syscalls; i++) {
62 if (syscalls_metadata[i]) {
63 if (!strcmp(syscalls_metadata[i]->name, name))
70 void set_syscall_enter_id(int num, int id)
72 syscalls_metadata[num]->enter_id = id;
75 void set_syscall_exit_id(int num, int id)
77 syscalls_metadata[num]->exit_id = id;
81 print_syscall_enter(struct trace_iterator *iter, int flags)
83 struct trace_seq *s = &iter->seq;
84 struct trace_entry *ent = iter->ent;
85 struct syscall_trace_enter *trace;
86 struct syscall_metadata *entry;
89 trace = (typeof(trace))ent;
91 entry = syscall_nr_to_meta(syscall);
96 if (entry->enter_id != ent->type) {
101 ret = trace_seq_printf(s, "%s(", entry->name);
103 return TRACE_TYPE_PARTIAL_LINE;
105 for (i = 0; i < entry->nb_args; i++) {
106 /* parameter types */
107 if (trace_flags & TRACE_ITER_VERBOSE) {
108 ret = trace_seq_printf(s, "%s ", entry->types[i]);
110 return TRACE_TYPE_PARTIAL_LINE;
112 /* parameter values */
113 ret = trace_seq_printf(s, "%s: %lx%s", entry->args[i],
115 i == entry->nb_args - 1 ? "" : ", ");
117 return TRACE_TYPE_PARTIAL_LINE;
120 ret = trace_seq_putc(s, ')');
122 return TRACE_TYPE_PARTIAL_LINE;
125 ret = trace_seq_putc(s, '\n');
127 return TRACE_TYPE_PARTIAL_LINE;
129 return TRACE_TYPE_HANDLED;
133 print_syscall_exit(struct trace_iterator *iter, int flags)
135 struct trace_seq *s = &iter->seq;
136 struct trace_entry *ent = iter->ent;
137 struct syscall_trace_exit *trace;
139 struct syscall_metadata *entry;
142 trace = (typeof(trace))ent;
144 entry = syscall_nr_to_meta(syscall);
147 trace_seq_printf(s, "\n");
148 return TRACE_TYPE_HANDLED;
151 if (entry->exit_id != ent->type) {
153 return TRACE_TYPE_UNHANDLED;
156 ret = trace_seq_printf(s, "%s -> 0x%lx\n", entry->name,
159 return TRACE_TYPE_PARTIAL_LINE;
161 return TRACE_TYPE_HANDLED;
164 extern char *__bad_type_size(void);
166 #define SYSCALL_FIELD(type, name) \
167 sizeof(type) != sizeof(trace.name) ? \
168 __bad_type_size() : \
169 #type, #name, offsetof(typeof(trace), name), \
170 sizeof(trace.name), is_signed_type(type)
172 int syscall_enter_format(struct ftrace_event_call *call, struct trace_seq *s)
177 struct syscall_metadata *entry;
178 struct syscall_trace_enter trace;
179 int offset = offsetof(struct syscall_trace_enter, args);
181 nr = syscall_name_to_nr(call->data);
182 entry = syscall_nr_to_meta(nr);
187 ret = trace_seq_printf(s, "\tfield:%s %s;\toffset:%zu;\tsize:%zu;"
189 SYSCALL_FIELD(int, nr));
193 for (i = 0; i < entry->nb_args; i++) {
194 ret = trace_seq_printf(s, "\tfield:%s %s;", entry->types[i],
198 ret = trace_seq_printf(s, "\toffset:%d;\tsize:%zu;"
199 "\tsigned:%u;\n", offset,
200 sizeof(unsigned long),
201 is_signed_type(unsigned long));
204 offset += sizeof(unsigned long);
207 trace_seq_puts(s, "\nprint fmt: \"");
208 for (i = 0; i < entry->nb_args; i++) {
209 ret = trace_seq_printf(s, "%s: 0x%%0%zulx%s", entry->args[i],
210 sizeof(unsigned long),
211 i == entry->nb_args - 1 ? "" : ", ");
215 trace_seq_putc(s, '"');
217 for (i = 0; i < entry->nb_args; i++) {
218 ret = trace_seq_printf(s, ", ((unsigned long)(REC->%s))",
224 return trace_seq_putc(s, '\n');
227 int syscall_exit_format(struct ftrace_event_call *call, struct trace_seq *s)
230 struct syscall_trace_exit trace;
232 ret = trace_seq_printf(s,
233 "\tfield:%s %s;\toffset:%zu;\tsize:%zu;"
235 "\tfield:%s %s;\toffset:%zu;\tsize:%zu;"
237 SYSCALL_FIELD(int, nr),
238 SYSCALL_FIELD(long, ret));
242 return trace_seq_printf(s, "\nprint fmt: \"0x%%lx\", REC->ret\n");
245 int syscall_enter_define_fields(struct ftrace_event_call *call)
247 struct syscall_trace_enter trace;
248 struct syscall_metadata *meta;
252 int offset = offsetof(typeof(trace), args);
254 nr = syscall_name_to_nr(call->data);
255 meta = syscall_nr_to_meta(nr);
260 ret = trace_define_common_fields(call);
264 for (i = 0; i < meta->nb_args; i++) {
265 ret = trace_define_field(call, meta->types[i],
266 meta->args[i], offset,
267 sizeof(unsigned long), 0,
269 offset += sizeof(unsigned long);
275 int syscall_exit_define_fields(struct ftrace_event_call *call)
277 struct syscall_trace_exit trace;
280 ret = trace_define_common_fields(call);
284 ret = trace_define_field(call, SYSCALL_FIELD(long, ret),
290 void ftrace_syscall_enter(struct pt_regs *regs, long id)
292 struct syscall_trace_enter *entry;
293 struct syscall_metadata *sys_data;
294 struct ring_buffer_event *event;
295 struct ring_buffer *buffer;
299 syscall_nr = syscall_get_nr(current, regs);
302 if (!test_bit(syscall_nr, enabled_enter_syscalls))
305 sys_data = syscall_nr_to_meta(syscall_nr);
309 size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args;
311 event = trace_current_buffer_lock_reserve(&buffer, sys_data->enter_id,
316 entry = ring_buffer_event_data(event);
317 entry->nr = syscall_nr;
318 syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args);
320 if (!filter_current_check_discard(buffer, sys_data->enter_event,
322 trace_current_buffer_unlock_commit(buffer, event, 0, 0);
325 void ftrace_syscall_exit(struct pt_regs *regs, long ret)
327 struct syscall_trace_exit *entry;
328 struct syscall_metadata *sys_data;
329 struct ring_buffer_event *event;
330 struct ring_buffer *buffer;
333 syscall_nr = syscall_get_nr(current, regs);
336 if (!test_bit(syscall_nr, enabled_exit_syscalls))
339 sys_data = syscall_nr_to_meta(syscall_nr);
343 event = trace_current_buffer_lock_reserve(&buffer, sys_data->exit_id,
344 sizeof(*entry), 0, 0);
348 entry = ring_buffer_event_data(event);
349 entry->nr = syscall_nr;
350 entry->ret = syscall_get_return_value(current, regs);
352 if (!filter_current_check_discard(buffer, sys_data->exit_event,
354 trace_current_buffer_unlock_commit(buffer, event, 0, 0);
357 int reg_event_syscall_enter(struct ftrace_event_call *call)
363 name = (char *)call->data;
364 num = syscall_name_to_nr(name);
365 if (num < 0 || num >= NR_syscalls)
367 mutex_lock(&syscall_trace_lock);
368 if (!sys_refcount_enter)
369 ret = register_trace_sys_enter(ftrace_syscall_enter);
371 pr_info("event trace: Could not activate"
372 "syscall entry trace point");
374 set_bit(num, enabled_enter_syscalls);
375 sys_refcount_enter++;
377 mutex_unlock(&syscall_trace_lock);
381 void unreg_event_syscall_enter(struct ftrace_event_call *call)
386 name = (char *)call->data;
387 num = syscall_name_to_nr(name);
388 if (num < 0 || num >= NR_syscalls)
390 mutex_lock(&syscall_trace_lock);
391 sys_refcount_enter--;
392 clear_bit(num, enabled_enter_syscalls);
393 if (!sys_refcount_enter)
394 unregister_trace_sys_enter(ftrace_syscall_enter);
395 mutex_unlock(&syscall_trace_lock);
398 int reg_event_syscall_exit(struct ftrace_event_call *call)
405 num = syscall_name_to_nr(name);
406 if (num < 0 || num >= NR_syscalls)
408 mutex_lock(&syscall_trace_lock);
409 if (!sys_refcount_exit)
410 ret = register_trace_sys_exit(ftrace_syscall_exit);
412 pr_info("event trace: Could not activate"
413 "syscall exit trace point");
415 set_bit(num, enabled_exit_syscalls);
418 mutex_unlock(&syscall_trace_lock);
422 void unreg_event_syscall_exit(struct ftrace_event_call *call)
428 num = syscall_name_to_nr(name);
429 if (num < 0 || num >= NR_syscalls)
431 mutex_lock(&syscall_trace_lock);
433 clear_bit(num, enabled_exit_syscalls);
434 if (!sys_refcount_exit)
435 unregister_trace_sys_exit(ftrace_syscall_exit);
436 mutex_unlock(&syscall_trace_lock);
439 struct trace_event event_syscall_enter = {
440 .trace = print_syscall_enter,
443 struct trace_event event_syscall_exit = {
444 .trace = print_syscall_exit,
447 int __init init_ftrace_syscalls(void)
449 struct syscall_metadata *meta;
453 syscalls_metadata = kzalloc(sizeof(*syscalls_metadata) *
454 NR_syscalls, GFP_KERNEL);
455 if (!syscalls_metadata) {
460 for (i = 0; i < NR_syscalls; i++) {
461 addr = arch_syscall_addr(i);
462 meta = find_syscall_meta(addr);
463 syscalls_metadata[i] = meta;
468 core_initcall(init_ftrace_syscalls);
470 #ifdef CONFIG_EVENT_PROFILE
472 static DECLARE_BITMAP(enabled_prof_enter_syscalls, NR_syscalls);
473 static DECLARE_BITMAP(enabled_prof_exit_syscalls, NR_syscalls);
474 static int sys_prof_refcount_enter;
475 static int sys_prof_refcount_exit;
477 static void prof_syscall_enter(struct pt_regs *regs, long id)
479 struct syscall_metadata *sys_data;
480 struct perf_trace_buf *trace_buf;
481 struct syscall_trace_enter *rec;
488 syscall_nr = syscall_get_nr(current, regs);
489 if (!test_bit(syscall_nr, enabled_prof_enter_syscalls))
492 sys_data = syscall_nr_to_meta(syscall_nr);
496 /* get the size after alignment with the u32 buffer size field */
497 size = sizeof(unsigned long) * sys_data->nb_args + sizeof(*rec);
498 size = ALIGN(size + sizeof(u32), sizeof(u64));
501 if (WARN_ONCE(size > FTRACE_MAX_PROFILE_SIZE,
502 "profile buffer not large enough"))
505 /* Protect the per cpu buffer, begin the rcu read side */
506 local_irq_save(flags);
508 cpu = smp_processor_id();
511 trace_buf = rcu_dereference(perf_trace_buf_nmi);
513 trace_buf = rcu_dereference(perf_trace_buf);
518 trace_buf = per_cpu_ptr(trace_buf, cpu);
520 if (trace_buf->recursion++)
524 * Make recursion update visible before entering perf_tp_event
525 * so that we protect from perf recursions.
529 raw_data = trace_buf->buf;
531 /* zero the dead bytes from align to not leak stack to user */
532 *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;
534 rec = (struct syscall_trace_enter *) raw_data;
535 tracing_generic_entry_update(&rec->ent, 0, 0);
536 rec->ent.type = sys_data->enter_id;
537 rec->nr = syscall_nr;
538 syscall_get_arguments(current, regs, 0, sys_data->nb_args,
539 (unsigned long *)&rec->args);
540 perf_tp_event(sys_data->enter_id, 0, 1, rec, size);
543 trace_buf->recursion--;
545 local_irq_restore(flags);
548 int reg_prof_syscall_enter(char *name)
553 num = syscall_name_to_nr(name);
554 if (num < 0 || num >= NR_syscalls)
557 mutex_lock(&syscall_trace_lock);
558 if (!sys_prof_refcount_enter)
559 ret = register_trace_sys_enter(prof_syscall_enter);
561 pr_info("event trace: Could not activate"
562 "syscall entry trace point");
564 set_bit(num, enabled_prof_enter_syscalls);
565 sys_prof_refcount_enter++;
567 mutex_unlock(&syscall_trace_lock);
571 void unreg_prof_syscall_enter(char *name)
575 num = syscall_name_to_nr(name);
576 if (num < 0 || num >= NR_syscalls)
579 mutex_lock(&syscall_trace_lock);
580 sys_prof_refcount_enter--;
581 clear_bit(num, enabled_prof_enter_syscalls);
582 if (!sys_prof_refcount_enter)
583 unregister_trace_sys_enter(prof_syscall_enter);
584 mutex_unlock(&syscall_trace_lock);
587 static void prof_syscall_exit(struct pt_regs *regs, long ret)
589 struct syscall_metadata *sys_data;
590 struct syscall_trace_exit *rec;
591 struct perf_trace_buf *trace_buf;
598 syscall_nr = syscall_get_nr(current, regs);
599 if (!test_bit(syscall_nr, enabled_prof_exit_syscalls))
602 sys_data = syscall_nr_to_meta(syscall_nr);
606 /* We can probably do that at build time */
607 size = ALIGN(sizeof(*rec) + sizeof(u32), sizeof(u64));
611 * Impossible, but be paranoid with the future
612 * How to put this check outside runtime?
614 if (WARN_ONCE(size > FTRACE_MAX_PROFILE_SIZE,
615 "exit event has grown above profile buffer size"))
618 /* Protect the per cpu buffer, begin the rcu read side */
619 local_irq_save(flags);
620 cpu = smp_processor_id();
623 trace_buf = rcu_dereference(perf_trace_buf_nmi);
625 trace_buf = rcu_dereference(perf_trace_buf);
630 trace_buf = per_cpu_ptr(trace_buf, cpu);
632 if (trace_buf->recursion++)
636 * Make recursion update visible before entering perf_tp_event
637 * so that we protect from perf recursions.
641 raw_data = trace_buf->buf;
643 /* zero the dead bytes from align to not leak stack to user */
644 *(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;
646 rec = (struct syscall_trace_exit *)raw_data;
648 tracing_generic_entry_update(&rec->ent, 0, 0);
649 rec->ent.type = sys_data->exit_id;
650 rec->nr = syscall_nr;
651 rec->ret = syscall_get_return_value(current, regs);
653 perf_tp_event(sys_data->exit_id, 0, 1, rec, size);
656 trace_buf->recursion--;
658 local_irq_restore(flags);
661 int reg_prof_syscall_exit(char *name)
666 num = syscall_name_to_nr(name);
667 if (num < 0 || num >= NR_syscalls)
670 mutex_lock(&syscall_trace_lock);
671 if (!sys_prof_refcount_exit)
672 ret = register_trace_sys_exit(prof_syscall_exit);
674 pr_info("event trace: Could not activate"
675 "syscall entry trace point");
677 set_bit(num, enabled_prof_exit_syscalls);
678 sys_prof_refcount_exit++;
680 mutex_unlock(&syscall_trace_lock);
684 void unreg_prof_syscall_exit(char *name)
688 num = syscall_name_to_nr(name);
689 if (num < 0 || num >= NR_syscalls)
692 mutex_lock(&syscall_trace_lock);
693 sys_prof_refcount_exit--;
694 clear_bit(num, enabled_prof_exit_syscalls);
695 if (!sys_prof_refcount_exit)
696 unregister_trace_sys_exit(prof_syscall_exit);
697 mutex_unlock(&syscall_trace_lock);