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>
11 #include "trace_output.h"
14 static DEFINE_MUTEX(syscall_trace_lock
);
16 static int syscall_enter_register(struct ftrace_event_call
*event
,
17 enum trace_reg type
, void *data
);
18 static int syscall_exit_register(struct ftrace_event_call
*event
,
19 enum trace_reg type
, void *data
);
21 static struct list_head
*
22 syscall_get_enter_fields(struct ftrace_event_call
*call
)
24 struct syscall_metadata
*entry
= call
->data
;
26 return &entry
->enter_fields
;
29 extern struct syscall_metadata
*__start_syscalls_metadata
[];
30 extern struct syscall_metadata
*__stop_syscalls_metadata
[];
32 static struct syscall_metadata
**syscalls_metadata
;
34 #ifndef ARCH_HAS_SYSCALL_MATCH_SYM_NAME
35 static inline bool arch_syscall_match_sym_name(const char *sym
, const char *name
)
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
43 return !strcmp(sym
+ 3, name
+ 3);
47 #ifdef ARCH_TRACE_IGNORE_COMPAT_SYSCALLS
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.
55 * In such a case, instead of reporting the wrong syscalls,
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.
64 trace_get_syscall_nr(struct task_struct
*task
, struct pt_regs
*regs
)
66 if (unlikely(arch_trace_is_compat_syscall(regs
)))
69 return syscall_get_nr(task
, regs
);
73 trace_get_syscall_nr(struct task_struct
*task
, struct pt_regs
*regs
)
75 return syscall_get_nr(task
, regs
);
77 #endif /* ARCH_TRACE_IGNORE_COMPAT_SYSCALLS */
79 static __init
struct syscall_metadata
*
80 find_syscall_meta(unsigned long syscall
)
82 struct syscall_metadata
**start
;
83 struct syscall_metadata
**stop
;
84 char str
[KSYM_SYMBOL_LEN
];
87 start
= __start_syscalls_metadata
;
88 stop
= __stop_syscalls_metadata
;
89 kallsyms_lookup(syscall
, NULL
, NULL
, NULL
, str
);
91 if (arch_syscall_match_sym_name(str
, "sys_ni_syscall"))
94 for ( ; start
< stop
; start
++) {
95 if ((*start
)->name
&& arch_syscall_match_sym_name(str
, (*start
)->name
))
101 static struct syscall_metadata
*syscall_nr_to_meta(int nr
)
103 if (!syscalls_metadata
|| nr
>= NR_syscalls
|| nr
< 0)
106 return syscalls_metadata
[nr
];
109 static enum print_line_t
110 print_syscall_enter(struct trace_iterator
*iter
, int flags
,
111 struct trace_event
*event
)
113 struct trace_seq
*s
= &iter
->seq
;
114 struct trace_entry
*ent
= iter
->ent
;
115 struct syscall_trace_enter
*trace
;
116 struct syscall_metadata
*entry
;
119 trace
= (typeof(trace
))ent
;
121 entry
= syscall_nr_to_meta(syscall
);
126 if (entry
->enter_event
->event
.type
!= ent
->type
) {
131 ret
= trace_seq_printf(s
, "%s(", entry
->name
);
133 return TRACE_TYPE_PARTIAL_LINE
;
135 for (i
= 0; i
< entry
->nb_args
; i
++) {
136 /* parameter types */
137 if (trace_flags
& TRACE_ITER_VERBOSE
) {
138 ret
= trace_seq_printf(s
, "%s ", entry
->types
[i
]);
140 return TRACE_TYPE_PARTIAL_LINE
;
142 /* parameter values */
143 ret
= trace_seq_printf(s
, "%s: %lx%s", entry
->args
[i
],
145 i
== entry
->nb_args
- 1 ? "" : ", ");
147 return TRACE_TYPE_PARTIAL_LINE
;
150 ret
= trace_seq_putc(s
, ')');
152 return TRACE_TYPE_PARTIAL_LINE
;
155 ret
= trace_seq_putc(s
, '\n');
157 return TRACE_TYPE_PARTIAL_LINE
;
159 return TRACE_TYPE_HANDLED
;
162 static enum print_line_t
163 print_syscall_exit(struct trace_iterator
*iter
, int flags
,
164 struct trace_event
*event
)
166 struct trace_seq
*s
= &iter
->seq
;
167 struct trace_entry
*ent
= iter
->ent
;
168 struct syscall_trace_exit
*trace
;
170 struct syscall_metadata
*entry
;
173 trace
= (typeof(trace
))ent
;
175 entry
= syscall_nr_to_meta(syscall
);
178 trace_seq_putc(s
, '\n');
179 return TRACE_TYPE_HANDLED
;
182 if (entry
->exit_event
->event
.type
!= ent
->type
) {
184 return TRACE_TYPE_UNHANDLED
;
187 ret
= trace_seq_printf(s
, "%s -> 0x%lx\n", entry
->name
,
190 return TRACE_TYPE_PARTIAL_LINE
;
192 return TRACE_TYPE_HANDLED
;
195 extern char *__bad_type_size(void);
197 #define SYSCALL_FIELD(type, name) \
198 sizeof(type) != sizeof(trace.name) ? \
199 __bad_type_size() : \
200 #type, #name, offsetof(typeof(trace), name), \
201 sizeof(trace.name), is_signed_type(type)
204 __set_enter_print_fmt(struct syscall_metadata
*entry
, char *buf
, int len
)
209 /* When len=0, we just calculate the needed length */
210 #define LEN_OR_ZERO (len ? len - pos : 0)
212 pos
+= snprintf(buf
+ pos
, LEN_OR_ZERO
, "\"");
213 for (i
= 0; i
< entry
->nb_args
; i
++) {
214 pos
+= snprintf(buf
+ pos
, LEN_OR_ZERO
, "%s: 0x%%0%zulx%s",
215 entry
->args
[i
], sizeof(unsigned long),
216 i
== entry
->nb_args
- 1 ? "" : ", ");
218 pos
+= snprintf(buf
+ pos
, LEN_OR_ZERO
, "\"");
220 for (i
= 0; i
< entry
->nb_args
; i
++) {
221 pos
+= snprintf(buf
+ pos
, LEN_OR_ZERO
,
222 ", ((unsigned long)(REC->%s))", entry
->args
[i
]);
227 /* return the length of print_fmt */
231 static int __init
set_syscall_print_fmt(struct ftrace_event_call
*call
)
235 struct syscall_metadata
*entry
= call
->data
;
237 if (entry
->enter_event
!= call
) {
238 call
->print_fmt
= "\"0x%lx\", REC->ret";
242 /* First: called with 0 length to calculate the needed length */
243 len
= __set_enter_print_fmt(entry
, NULL
, 0);
245 print_fmt
= kmalloc(len
+ 1, GFP_KERNEL
);
249 /* Second: actually write the @print_fmt */
250 __set_enter_print_fmt(entry
, print_fmt
, len
+ 1);
251 call
->print_fmt
= print_fmt
;
256 static void __init
free_syscall_print_fmt(struct ftrace_event_call
*call
)
258 struct syscall_metadata
*entry
= call
->data
;
260 if (entry
->enter_event
== call
)
261 kfree(call
->print_fmt
);
264 static int __init
syscall_enter_define_fields(struct ftrace_event_call
*call
)
266 struct syscall_trace_enter trace
;
267 struct syscall_metadata
*meta
= call
->data
;
270 int offset
= offsetof(typeof(trace
), args
);
272 ret
= trace_define_field(call
, SYSCALL_FIELD(int, nr
), FILTER_OTHER
);
276 for (i
= 0; i
< meta
->nb_args
; i
++) {
277 ret
= trace_define_field(call
, meta
->types
[i
],
278 meta
->args
[i
], offset
,
279 sizeof(unsigned long), 0,
281 offset
+= sizeof(unsigned long);
287 static int __init
syscall_exit_define_fields(struct ftrace_event_call
*call
)
289 struct syscall_trace_exit trace
;
292 ret
= trace_define_field(call
, SYSCALL_FIELD(int, nr
), FILTER_OTHER
);
296 ret
= trace_define_field(call
, SYSCALL_FIELD(long, ret
),
302 static void ftrace_syscall_enter(void *data
, struct pt_regs
*regs
, long id
)
304 struct trace_array
*tr
= data
;
305 struct ftrace_event_file
*ftrace_file
;
306 struct syscall_trace_enter
*entry
;
307 struct syscall_metadata
*sys_data
;
308 struct ring_buffer_event
*event
;
309 struct ring_buffer
*buffer
;
310 unsigned long irq_flags
;
315 syscall_nr
= trace_get_syscall_nr(current
, regs
);
319 /* Here we're inside tp handler's rcu_read_lock_sched (__DO_TRACE) */
320 ftrace_file
= rcu_dereference_sched(tr
->enter_syscall_files
[syscall_nr
]);
324 if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT
, &ftrace_file
->flags
))
327 sys_data
= syscall_nr_to_meta(syscall_nr
);
331 size
= sizeof(*entry
) + sizeof(unsigned long) * sys_data
->nb_args
;
333 local_save_flags(irq_flags
);
334 pc
= preempt_count();
336 buffer
= tr
->trace_buffer
.buffer
;
337 event
= trace_buffer_lock_reserve(buffer
,
338 sys_data
->enter_event
->event
.type
, size
, irq_flags
, pc
);
342 entry
= ring_buffer_event_data(event
);
343 entry
->nr
= syscall_nr
;
344 syscall_get_arguments(current
, regs
, 0, sys_data
->nb_args
, entry
->args
);
346 if (!filter_check_discard(ftrace_file
, entry
, buffer
, event
))
347 trace_current_buffer_unlock_commit(buffer
, event
,
351 static void ftrace_syscall_exit(void *data
, struct pt_regs
*regs
, long ret
)
353 struct trace_array
*tr
= data
;
354 struct ftrace_event_file
*ftrace_file
;
355 struct syscall_trace_exit
*entry
;
356 struct syscall_metadata
*sys_data
;
357 struct ring_buffer_event
*event
;
358 struct ring_buffer
*buffer
;
359 unsigned long irq_flags
;
363 syscall_nr
= trace_get_syscall_nr(current
, regs
);
367 /* Here we're inside tp handler's rcu_read_lock_sched (__DO_TRACE()) */
368 ftrace_file
= rcu_dereference_sched(tr
->exit_syscall_files
[syscall_nr
]);
372 if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT
, &ftrace_file
->flags
))
375 sys_data
= syscall_nr_to_meta(syscall_nr
);
379 local_save_flags(irq_flags
);
380 pc
= preempt_count();
382 buffer
= tr
->trace_buffer
.buffer
;
383 event
= trace_buffer_lock_reserve(buffer
,
384 sys_data
->exit_event
->event
.type
, sizeof(*entry
),
389 entry
= ring_buffer_event_data(event
);
390 entry
->nr
= syscall_nr
;
391 entry
->ret
= syscall_get_return_value(current
, regs
);
393 if (!filter_check_discard(ftrace_file
, entry
, buffer
, event
))
394 trace_current_buffer_unlock_commit(buffer
, event
,
398 static int reg_event_syscall_enter(struct ftrace_event_file
*file
,
399 struct ftrace_event_call
*call
)
401 struct trace_array
*tr
= file
->tr
;
405 num
= ((struct syscall_metadata
*)call
->data
)->syscall_nr
;
406 if (WARN_ON_ONCE(num
< 0 || num
>= NR_syscalls
))
408 mutex_lock(&syscall_trace_lock
);
409 if (!tr
->sys_refcount_enter
)
410 ret
= register_trace_sys_enter(ftrace_syscall_enter
, tr
);
412 rcu_assign_pointer(tr
->enter_syscall_files
[num
], file
);
413 tr
->sys_refcount_enter
++;
415 mutex_unlock(&syscall_trace_lock
);
419 static void unreg_event_syscall_enter(struct ftrace_event_file
*file
,
420 struct ftrace_event_call
*call
)
422 struct trace_array
*tr
= file
->tr
;
425 num
= ((struct syscall_metadata
*)call
->data
)->syscall_nr
;
426 if (WARN_ON_ONCE(num
< 0 || num
>= NR_syscalls
))
428 mutex_lock(&syscall_trace_lock
);
429 tr
->sys_refcount_enter
--;
430 rcu_assign_pointer(tr
->enter_syscall_files
[num
], NULL
);
431 if (!tr
->sys_refcount_enter
)
432 unregister_trace_sys_enter(ftrace_syscall_enter
, tr
);
433 mutex_unlock(&syscall_trace_lock
);
436 static int reg_event_syscall_exit(struct ftrace_event_file
*file
,
437 struct ftrace_event_call
*call
)
439 struct trace_array
*tr
= file
->tr
;
443 num
= ((struct syscall_metadata
*)call
->data
)->syscall_nr
;
444 if (WARN_ON_ONCE(num
< 0 || num
>= NR_syscalls
))
446 mutex_lock(&syscall_trace_lock
);
447 if (!tr
->sys_refcount_exit
)
448 ret
= register_trace_sys_exit(ftrace_syscall_exit
, tr
);
450 rcu_assign_pointer(tr
->exit_syscall_files
[num
], file
);
451 tr
->sys_refcount_exit
++;
453 mutex_unlock(&syscall_trace_lock
);
457 static void unreg_event_syscall_exit(struct ftrace_event_file
*file
,
458 struct ftrace_event_call
*call
)
460 struct trace_array
*tr
= file
->tr
;
463 num
= ((struct syscall_metadata
*)call
->data
)->syscall_nr
;
464 if (WARN_ON_ONCE(num
< 0 || num
>= NR_syscalls
))
466 mutex_lock(&syscall_trace_lock
);
467 tr
->sys_refcount_exit
--;
468 rcu_assign_pointer(tr
->exit_syscall_files
[num
], NULL
);
469 if (!tr
->sys_refcount_exit
)
470 unregister_trace_sys_exit(ftrace_syscall_exit
, tr
);
471 mutex_unlock(&syscall_trace_lock
);
474 static int __init
init_syscall_trace(struct ftrace_event_call
*call
)
479 num
= ((struct syscall_metadata
*)call
->data
)->syscall_nr
;
480 if (num
< 0 || num
>= NR_syscalls
) {
481 pr_debug("syscall %s metadata not mapped, disabling ftrace event\n",
482 ((struct syscall_metadata
*)call
->data
)->name
);
486 if (set_syscall_print_fmt(call
) < 0)
489 id
= trace_event_raw_init(call
);
492 free_syscall_print_fmt(call
);
499 struct trace_event_functions enter_syscall_print_funcs
= {
500 .trace
= print_syscall_enter
,
503 struct trace_event_functions exit_syscall_print_funcs
= {
504 .trace
= print_syscall_exit
,
507 struct ftrace_event_class __refdata event_class_syscall_enter
= {
508 .system
= "syscalls",
509 .reg
= syscall_enter_register
,
510 .define_fields
= syscall_enter_define_fields
,
511 .get_fields
= syscall_get_enter_fields
,
512 .raw_init
= init_syscall_trace
,
515 struct ftrace_event_class __refdata event_class_syscall_exit
= {
516 .system
= "syscalls",
517 .reg
= syscall_exit_register
,
518 .define_fields
= syscall_exit_define_fields
,
519 .fields
= LIST_HEAD_INIT(event_class_syscall_exit
.fields
),
520 .raw_init
= init_syscall_trace
,
523 unsigned long __init __weak
arch_syscall_addr(int nr
)
525 return (unsigned long)sys_call_table
[nr
];
528 static int __init
init_ftrace_syscalls(void)
530 struct syscall_metadata
*meta
;
534 syscalls_metadata
= kcalloc(NR_syscalls
, sizeof(*syscalls_metadata
),
536 if (!syscalls_metadata
) {
541 for (i
= 0; i
< NR_syscalls
; i
++) {
542 addr
= arch_syscall_addr(i
);
543 meta
= find_syscall_meta(addr
);
547 meta
->syscall_nr
= i
;
548 syscalls_metadata
[i
] = meta
;
553 early_initcall(init_ftrace_syscalls
);
555 #ifdef CONFIG_PERF_EVENTS
557 static DECLARE_BITMAP(enabled_perf_enter_syscalls
, NR_syscalls
);
558 static DECLARE_BITMAP(enabled_perf_exit_syscalls
, NR_syscalls
);
559 static int sys_perf_refcount_enter
;
560 static int sys_perf_refcount_exit
;
562 static void perf_syscall_enter(void *ignore
, struct pt_regs
*regs
, long id
)
564 struct syscall_metadata
*sys_data
;
565 struct syscall_trace_enter
*rec
;
566 struct hlist_head
*head
;
571 syscall_nr
= trace_get_syscall_nr(current
, regs
);
574 if (!test_bit(syscall_nr
, enabled_perf_enter_syscalls
))
577 sys_data
= syscall_nr_to_meta(syscall_nr
);
581 head
= this_cpu_ptr(sys_data
->enter_event
->perf_events
);
582 if (hlist_empty(head
))
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
));
590 rec
= (struct syscall_trace_enter
*)perf_trace_buf_prepare(size
,
591 sys_data
->enter_event
->event
.type
, regs
, &rctx
);
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
);
601 static int perf_sysenter_enable(struct ftrace_event_call
*call
)
606 num
= ((struct syscall_metadata
*)call
->data
)->syscall_nr
;
608 mutex_lock(&syscall_trace_lock
);
609 if (!sys_perf_refcount_enter
)
610 ret
= register_trace_sys_enter(perf_syscall_enter
, NULL
);
612 pr_info("event trace: Could not activate"
613 "syscall entry trace point");
615 set_bit(num
, enabled_perf_enter_syscalls
);
616 sys_perf_refcount_enter
++;
618 mutex_unlock(&syscall_trace_lock
);
622 static void perf_sysenter_disable(struct ftrace_event_call
*call
)
626 num
= ((struct syscall_metadata
*)call
->data
)->syscall_nr
;
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
);
636 static void perf_syscall_exit(void *ignore
, struct pt_regs
*regs
, long ret
)
638 struct syscall_metadata
*sys_data
;
639 struct syscall_trace_exit
*rec
;
640 struct hlist_head
*head
;
645 syscall_nr
= trace_get_syscall_nr(current
, regs
);
648 if (!test_bit(syscall_nr
, enabled_perf_exit_syscalls
))
651 sys_data
= syscall_nr_to_meta(syscall_nr
);
655 head
= this_cpu_ptr(sys_data
->exit_event
->perf_events
);
656 if (hlist_empty(head
))
659 /* We can probably do that at build time */
660 size
= ALIGN(sizeof(*rec
) + sizeof(u32
), sizeof(u64
));
663 rec
= (struct syscall_trace_exit
*)perf_trace_buf_prepare(size
,
664 sys_data
->exit_event
->event
.type
, regs
, &rctx
);
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
);
673 static int perf_sysexit_enable(struct ftrace_event_call
*call
)
678 num
= ((struct syscall_metadata
*)call
->data
)->syscall_nr
;
680 mutex_lock(&syscall_trace_lock
);
681 if (!sys_perf_refcount_exit
)
682 ret
= register_trace_sys_exit(perf_syscall_exit
, NULL
);
684 pr_info("event trace: Could not activate"
685 "syscall exit trace point");
687 set_bit(num
, enabled_perf_exit_syscalls
);
688 sys_perf_refcount_exit
++;
690 mutex_unlock(&syscall_trace_lock
);
694 static void perf_sysexit_disable(struct ftrace_event_call
*call
)
698 num
= ((struct syscall_metadata
*)call
->data
)->syscall_nr
;
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
);
708 #endif /* CONFIG_PERF_EVENTS */
710 static int syscall_enter_register(struct ftrace_event_call
*event
,
711 enum trace_reg type
, void *data
)
713 struct ftrace_event_file
*file
= data
;
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
);
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
);
728 case TRACE_REG_PERF_OPEN
:
729 case TRACE_REG_PERF_CLOSE
:
730 case TRACE_REG_PERF_ADD
:
731 case TRACE_REG_PERF_DEL
:
738 static int syscall_exit_register(struct ftrace_event_call
*event
,
739 enum trace_reg type
, void *data
)
741 struct ftrace_event_file
*file
= data
;
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
);
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
);
756 case TRACE_REG_PERF_OPEN
:
757 case TRACE_REG_PERF_CLOSE
:
758 case TRACE_REG_PERF_ADD
:
759 case TRACE_REG_PERF_DEL
: