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
];
55 print_syscall_enter(struct trace_iterator
*iter
, int flags
)
57 struct trace_seq
*s
= &iter
->seq
;
58 struct trace_entry
*ent
= iter
->ent
;
59 struct syscall_trace_enter
*trace
;
60 struct syscall_metadata
*entry
;
63 trace
= (typeof(trace
))ent
;
65 entry
= syscall_nr_to_meta(syscall
);
70 if (entry
->enter_event
->id
!= ent
->type
) {
75 ret
= trace_seq_printf(s
, "%s(", entry
->name
);
77 return TRACE_TYPE_PARTIAL_LINE
;
79 for (i
= 0; i
< entry
->nb_args
; i
++) {
81 if (trace_flags
& TRACE_ITER_VERBOSE
) {
82 ret
= trace_seq_printf(s
, "%s ", entry
->types
[i
]);
84 return TRACE_TYPE_PARTIAL_LINE
;
86 /* parameter values */
87 ret
= trace_seq_printf(s
, "%s: %lx%s", entry
->args
[i
],
89 i
== entry
->nb_args
- 1 ? "" : ", ");
91 return TRACE_TYPE_PARTIAL_LINE
;
94 ret
= trace_seq_putc(s
, ')');
96 return TRACE_TYPE_PARTIAL_LINE
;
99 ret
= trace_seq_putc(s
, '\n');
101 return TRACE_TYPE_PARTIAL_LINE
;
103 return TRACE_TYPE_HANDLED
;
107 print_syscall_exit(struct trace_iterator
*iter
, int flags
)
109 struct trace_seq
*s
= &iter
->seq
;
110 struct trace_entry
*ent
= iter
->ent
;
111 struct syscall_trace_exit
*trace
;
113 struct syscall_metadata
*entry
;
116 trace
= (typeof(trace
))ent
;
118 entry
= syscall_nr_to_meta(syscall
);
121 trace_seq_printf(s
, "\n");
122 return TRACE_TYPE_HANDLED
;
125 if (entry
->exit_event
->id
!= ent
->type
) {
127 return TRACE_TYPE_UNHANDLED
;
130 ret
= trace_seq_printf(s
, "%s -> 0x%lx\n", entry
->name
,
133 return TRACE_TYPE_PARTIAL_LINE
;
135 return TRACE_TYPE_HANDLED
;
138 extern char *__bad_type_size(void);
140 #define SYSCALL_FIELD(type, name) \
141 sizeof(type) != sizeof(trace.name) ? \
142 __bad_type_size() : \
143 #type, #name, offsetof(typeof(trace), name), \
144 sizeof(trace.name), is_signed_type(type)
147 int __set_enter_print_fmt(struct syscall_metadata
*entry
, char *buf
, int len
)
152 /* When len=0, we just calculate the needed length */
153 #define LEN_OR_ZERO (len ? len - pos : 0)
155 pos
+= snprintf(buf
+ pos
, LEN_OR_ZERO
, "\"");
156 for (i
= 0; i
< entry
->nb_args
; i
++) {
157 pos
+= snprintf(buf
+ pos
, LEN_OR_ZERO
, "%s: 0x%%0%zulx%s",
158 entry
->args
[i
], sizeof(unsigned long),
159 i
== entry
->nb_args
- 1 ? "" : ", ");
161 pos
+= snprintf(buf
+ pos
, LEN_OR_ZERO
, "\"");
163 for (i
= 0; i
< entry
->nb_args
; i
++) {
164 pos
+= snprintf(buf
+ pos
, LEN_OR_ZERO
,
165 ", ((unsigned long)(REC->%s))", entry
->args
[i
]);
170 /* return the length of print_fmt */
174 static int set_syscall_print_fmt(struct ftrace_event_call
*call
)
178 struct syscall_metadata
*entry
= call
->data
;
180 if (entry
->enter_event
!= call
) {
181 call
->print_fmt
= "\"0x%lx\", REC->ret";
185 /* First: called with 0 length to calculate the needed length */
186 len
= __set_enter_print_fmt(entry
, NULL
, 0);
188 print_fmt
= kmalloc(len
+ 1, GFP_KERNEL
);
192 /* Second: actually write the @print_fmt */
193 __set_enter_print_fmt(entry
, print_fmt
, len
+ 1);
194 call
->print_fmt
= print_fmt
;
199 static void free_syscall_print_fmt(struct ftrace_event_call
*call
)
201 struct syscall_metadata
*entry
= call
->data
;
203 if (entry
->enter_event
== call
)
204 kfree(call
->print_fmt
);
207 int syscall_enter_define_fields(struct ftrace_event_call
*call
)
209 struct syscall_trace_enter trace
;
210 struct syscall_metadata
*meta
= call
->data
;
213 int offset
= offsetof(typeof(trace
), args
);
215 ret
= trace_define_field(call
, SYSCALL_FIELD(int, nr
), FILTER_OTHER
);
219 for (i
= 0; i
< meta
->nb_args
; i
++) {
220 ret
= trace_define_field(call
, meta
->types
[i
],
221 meta
->args
[i
], offset
,
222 sizeof(unsigned long), 0,
224 offset
+= sizeof(unsigned long);
230 int syscall_exit_define_fields(struct ftrace_event_call
*call
)
232 struct syscall_trace_exit trace
;
235 ret
= trace_define_field(call
, SYSCALL_FIELD(int, nr
), FILTER_OTHER
);
239 ret
= trace_define_field(call
, SYSCALL_FIELD(long, ret
),
245 void ftrace_syscall_enter(struct pt_regs
*regs
, long id
)
247 struct syscall_trace_enter
*entry
;
248 struct syscall_metadata
*sys_data
;
249 struct ring_buffer_event
*event
;
250 struct ring_buffer
*buffer
;
254 syscall_nr
= syscall_get_nr(current
, regs
);
257 if (!test_bit(syscall_nr
, enabled_enter_syscalls
))
260 sys_data
= syscall_nr_to_meta(syscall_nr
);
264 size
= sizeof(*entry
) + sizeof(unsigned long) * sys_data
->nb_args
;
266 event
= trace_current_buffer_lock_reserve(&buffer
,
267 sys_data
->enter_event
->id
, size
, 0, 0);
271 entry
= ring_buffer_event_data(event
);
272 entry
->nr
= syscall_nr
;
273 syscall_get_arguments(current
, regs
, 0, sys_data
->nb_args
, entry
->args
);
275 if (!filter_current_check_discard(buffer
, sys_data
->enter_event
,
277 trace_current_buffer_unlock_commit(buffer
, event
, 0, 0);
280 void ftrace_syscall_exit(struct pt_regs
*regs
, long ret
)
282 struct syscall_trace_exit
*entry
;
283 struct syscall_metadata
*sys_data
;
284 struct ring_buffer_event
*event
;
285 struct ring_buffer
*buffer
;
288 syscall_nr
= syscall_get_nr(current
, regs
);
291 if (!test_bit(syscall_nr
, enabled_exit_syscalls
))
294 sys_data
= syscall_nr_to_meta(syscall_nr
);
298 event
= trace_current_buffer_lock_reserve(&buffer
,
299 sys_data
->exit_event
->id
, sizeof(*entry
), 0, 0);
303 entry
= ring_buffer_event_data(event
);
304 entry
->nr
= syscall_nr
;
305 entry
->ret
= syscall_get_return_value(current
, regs
);
307 if (!filter_current_check_discard(buffer
, sys_data
->exit_event
,
309 trace_current_buffer_unlock_commit(buffer
, event
, 0, 0);
312 int reg_event_syscall_enter(struct ftrace_event_call
*call
)
317 num
= ((struct syscall_metadata
*)call
->data
)->syscall_nr
;
318 if (num
< 0 || num
>= NR_syscalls
)
320 mutex_lock(&syscall_trace_lock
);
321 if (!sys_refcount_enter
)
322 ret
= register_trace_sys_enter(ftrace_syscall_enter
);
324 set_bit(num
, enabled_enter_syscalls
);
325 sys_refcount_enter
++;
327 mutex_unlock(&syscall_trace_lock
);
331 void unreg_event_syscall_enter(struct ftrace_event_call
*call
)
335 num
= ((struct syscall_metadata
*)call
->data
)->syscall_nr
;
336 if (num
< 0 || num
>= NR_syscalls
)
338 mutex_lock(&syscall_trace_lock
);
339 sys_refcount_enter
--;
340 clear_bit(num
, enabled_enter_syscalls
);
341 if (!sys_refcount_enter
)
342 unregister_trace_sys_enter(ftrace_syscall_enter
);
343 mutex_unlock(&syscall_trace_lock
);
346 int reg_event_syscall_exit(struct ftrace_event_call
*call
)
351 num
= ((struct syscall_metadata
*)call
->data
)->syscall_nr
;
352 if (num
< 0 || num
>= NR_syscalls
)
354 mutex_lock(&syscall_trace_lock
);
355 if (!sys_refcount_exit
)
356 ret
= register_trace_sys_exit(ftrace_syscall_exit
);
358 set_bit(num
, enabled_exit_syscalls
);
361 mutex_unlock(&syscall_trace_lock
);
365 void unreg_event_syscall_exit(struct ftrace_event_call
*call
)
369 num
= ((struct syscall_metadata
*)call
->data
)->syscall_nr
;
370 if (num
< 0 || num
>= NR_syscalls
)
372 mutex_lock(&syscall_trace_lock
);
374 clear_bit(num
, enabled_exit_syscalls
);
375 if (!sys_refcount_exit
)
376 unregister_trace_sys_exit(ftrace_syscall_exit
);
377 mutex_unlock(&syscall_trace_lock
);
380 int init_syscall_trace(struct ftrace_event_call
*call
)
384 if (set_syscall_print_fmt(call
) < 0)
387 id
= trace_event_raw_init(call
);
390 free_syscall_print_fmt(call
);
397 int __init
init_ftrace_syscalls(void)
399 struct syscall_metadata
*meta
;
403 syscalls_metadata
= kzalloc(sizeof(*syscalls_metadata
) *
404 NR_syscalls
, GFP_KERNEL
);
405 if (!syscalls_metadata
) {
410 for (i
= 0; i
< NR_syscalls
; i
++) {
411 addr
= arch_syscall_addr(i
);
412 meta
= find_syscall_meta(addr
);
416 meta
->syscall_nr
= i
;
417 syscalls_metadata
[i
] = meta
;
422 core_initcall(init_ftrace_syscalls
);
424 #ifdef CONFIG_EVENT_PROFILE
426 static DECLARE_BITMAP(enabled_prof_enter_syscalls
, NR_syscalls
);
427 static DECLARE_BITMAP(enabled_prof_exit_syscalls
, NR_syscalls
);
428 static int sys_prof_refcount_enter
;
429 static int sys_prof_refcount_exit
;
431 static void prof_syscall_enter(struct pt_regs
*regs
, long id
)
433 struct syscall_metadata
*sys_data
;
434 struct syscall_trace_enter
*rec
;
443 syscall_nr
= syscall_get_nr(current
, regs
);
444 if (!test_bit(syscall_nr
, enabled_prof_enter_syscalls
))
447 sys_data
= syscall_nr_to_meta(syscall_nr
);
451 /* get the size after alignment with the u32 buffer size field */
452 size
= sizeof(unsigned long) * sys_data
->nb_args
+ sizeof(*rec
);
453 size
= ALIGN(size
+ sizeof(u32
), sizeof(u64
));
456 if (WARN_ONCE(size
> FTRACE_MAX_PROFILE_SIZE
,
457 "profile buffer not large enough"))
460 /* Protect the per cpu buffer, begin the rcu read side */
461 local_irq_save(flags
);
463 rctx
= perf_swevent_get_recursion_context();
467 cpu
= smp_processor_id();
469 trace_buf
= rcu_dereference(perf_trace_buf
);
474 raw_data
= per_cpu_ptr(trace_buf
, cpu
);
476 /* zero the dead bytes from align to not leak stack to user */
477 *(u64
*)(&raw_data
[size
- sizeof(u64
)]) = 0ULL;
479 rec
= (struct syscall_trace_enter
*) raw_data
;
480 tracing_generic_entry_update(&rec
->ent
, 0, 0);
481 rec
->ent
.type
= sys_data
->enter_event
->id
;
482 rec
->nr
= syscall_nr
;
483 syscall_get_arguments(current
, regs
, 0, sys_data
->nb_args
,
484 (unsigned long *)&rec
->args
);
485 perf_tp_event(sys_data
->enter_event
->id
, 0, 1, rec
, size
);
488 perf_swevent_put_recursion_context(rctx
);
490 local_irq_restore(flags
);
493 int prof_sysenter_enable(struct ftrace_event_call
*call
)
498 num
= ((struct syscall_metadata
*)call
->data
)->syscall_nr
;
500 mutex_lock(&syscall_trace_lock
);
501 if (!sys_prof_refcount_enter
)
502 ret
= register_trace_sys_enter(prof_syscall_enter
);
504 pr_info("event trace: Could not activate"
505 "syscall entry trace point");
507 set_bit(num
, enabled_prof_enter_syscalls
);
508 sys_prof_refcount_enter
++;
510 mutex_unlock(&syscall_trace_lock
);
514 void prof_sysenter_disable(struct ftrace_event_call
*call
)
518 num
= ((struct syscall_metadata
*)call
->data
)->syscall_nr
;
520 mutex_lock(&syscall_trace_lock
);
521 sys_prof_refcount_enter
--;
522 clear_bit(num
, enabled_prof_enter_syscalls
);
523 if (!sys_prof_refcount_enter
)
524 unregister_trace_sys_enter(prof_syscall_enter
);
525 mutex_unlock(&syscall_trace_lock
);
528 static void prof_syscall_exit(struct pt_regs
*regs
, long ret
)
530 struct syscall_metadata
*sys_data
;
531 struct syscall_trace_exit
*rec
;
540 syscall_nr
= syscall_get_nr(current
, regs
);
541 if (!test_bit(syscall_nr
, enabled_prof_exit_syscalls
))
544 sys_data
= syscall_nr_to_meta(syscall_nr
);
548 /* We can probably do that at build time */
549 size
= ALIGN(sizeof(*rec
) + sizeof(u32
), sizeof(u64
));
553 * Impossible, but be paranoid with the future
554 * How to put this check outside runtime?
556 if (WARN_ONCE(size
> FTRACE_MAX_PROFILE_SIZE
,
557 "exit event has grown above profile buffer size"))
560 /* Protect the per cpu buffer, begin the rcu read side */
561 local_irq_save(flags
);
563 rctx
= perf_swevent_get_recursion_context();
567 cpu
= smp_processor_id();
569 trace_buf
= rcu_dereference(perf_trace_buf
);
574 raw_data
= per_cpu_ptr(trace_buf
, cpu
);
576 /* zero the dead bytes from align to not leak stack to user */
577 *(u64
*)(&raw_data
[size
- sizeof(u64
)]) = 0ULL;
579 rec
= (struct syscall_trace_exit
*)raw_data
;
581 tracing_generic_entry_update(&rec
->ent
, 0, 0);
582 rec
->ent
.type
= sys_data
->exit_event
->id
;
583 rec
->nr
= syscall_nr
;
584 rec
->ret
= syscall_get_return_value(current
, regs
);
586 perf_tp_event(sys_data
->exit_event
->id
, 0, 1, rec
, size
);
589 perf_swevent_put_recursion_context(rctx
);
591 local_irq_restore(flags
);
594 int prof_sysexit_enable(struct ftrace_event_call
*call
)
599 num
= ((struct syscall_metadata
*)call
->data
)->syscall_nr
;
601 mutex_lock(&syscall_trace_lock
);
602 if (!sys_prof_refcount_exit
)
603 ret
= register_trace_sys_exit(prof_syscall_exit
);
605 pr_info("event trace: Could not activate"
606 "syscall exit trace point");
608 set_bit(num
, enabled_prof_exit_syscalls
);
609 sys_prof_refcount_exit
++;
611 mutex_unlock(&syscall_trace_lock
);
615 void prof_sysexit_disable(struct ftrace_event_call
*call
)
619 num
= ((struct syscall_metadata
*)call
->data
)->syscall_nr
;
621 mutex_lock(&syscall_trace_lock
);
622 sys_prof_refcount_exit
--;
623 clear_bit(num
, enabled_prof_exit_syscalls
);
624 if (!sys_prof_refcount_exit
)
625 unregister_trace_sys_exit(prof_syscall_exit
);
626 mutex_unlock(&syscall_trace_lock
);