1 #include <trace/syscall.h>
2 #include <trace/events/syscalls.h>
3 #include <linux/slab.h>
4 #include <linux/kernel.h>
5 #include <linux/module.h> /* for MODULE_NAME_LEN via KSYM_SYMBOL_LEN */
6 #include <linux/ftrace.h>
7 #include <linux/perf_event.h>
8 #include <asm/syscall.h>
10 #include "trace_output.h"
13 static DEFINE_MUTEX(syscall_trace_lock);
14 static int sys_refcount_enter;
15 static int sys_refcount_exit;
16 static DECLARE_BITMAP(enabled_enter_syscalls, NR_syscalls);
17 static DECLARE_BITMAP(enabled_exit_syscalls, NR_syscalls);
19 static int syscall_enter_register(struct ftrace_event_call *event,
21 static int syscall_exit_register(struct ftrace_event_call *event,
24 static int syscall_enter_define_fields(struct ftrace_event_call *call);
25 static int syscall_exit_define_fields(struct ftrace_event_call *call);
27 static struct list_head *
28 syscall_get_enter_fields(struct ftrace_event_call *call)
30 struct syscall_metadata *entry = call->data;
32 return &entry->enter_fields;
35 struct trace_event_functions enter_syscall_print_funcs = {
36 .trace = print_syscall_enter,
39 struct trace_event_functions exit_syscall_print_funcs = {
40 .trace = print_syscall_exit,
43 struct ftrace_event_class event_class_syscall_enter = {
45 .reg = syscall_enter_register,
46 .define_fields = syscall_enter_define_fields,
47 .get_fields = syscall_get_enter_fields,
48 .raw_init = init_syscall_trace,
51 struct ftrace_event_class event_class_syscall_exit = {
53 .reg = syscall_exit_register,
54 .define_fields = syscall_exit_define_fields,
55 .fields = LIST_HEAD_INIT(event_class_syscall_exit.fields),
56 .raw_init = init_syscall_trace,
59 extern struct syscall_metadata *__start_syscalls_metadata[];
60 extern struct syscall_metadata *__stop_syscalls_metadata[];
62 static struct syscall_metadata **syscalls_metadata;
64 #ifndef ARCH_HAS_SYSCALL_MATCH_SYM_NAME
65 static inline bool arch_syscall_match_sym_name(const char *sym, const char *name)
68 * Only compare after the "sys" prefix. Archs that use
69 * syscall wrappers may have syscalls symbols aliases prefixed
70 * with "SyS" instead of "sys", leading to an unwanted
73 return !strcmp(sym + 3, name + 3);
77 static __init struct syscall_metadata *
78 find_syscall_meta(unsigned long syscall)
80 struct syscall_metadata **start;
81 struct syscall_metadata **stop;
82 char str[KSYM_SYMBOL_LEN];
85 start = __start_syscalls_metadata;
86 stop = __stop_syscalls_metadata;
87 kallsyms_lookup(syscall, NULL, NULL, NULL, str);
89 if (arch_syscall_match_sym_name(str, "sys_ni_syscall"))
92 for ( ; start < stop; start++) {
93 if ((*start)->name && arch_syscall_match_sym_name(str, (*start)->name))
99 static struct syscall_metadata *syscall_nr_to_meta(int nr)
101 if (!syscalls_metadata || nr >= NR_syscalls || nr < 0)
104 return syscalls_metadata[nr];
108 print_syscall_enter(struct trace_iterator *iter, int flags,
109 struct trace_event *event)
111 struct trace_seq *s = &iter->seq;
112 struct trace_entry *ent = iter->ent;
113 struct syscall_trace_enter *trace;
114 struct syscall_metadata *entry;
117 trace = (typeof(trace))ent;
119 entry = syscall_nr_to_meta(syscall);
124 if (entry->enter_event->event.type != ent->type) {
129 ret = trace_seq_printf(s, "%s(", entry->name);
131 return TRACE_TYPE_PARTIAL_LINE;
133 for (i = 0; i < entry->nb_args; i++) {
134 /* parameter types */
135 if (trace_flags & TRACE_ITER_VERBOSE) {
136 ret = trace_seq_printf(s, "%s ", entry->types[i]);
138 return TRACE_TYPE_PARTIAL_LINE;
140 /* parameter values */
141 ret = trace_seq_printf(s, "%s: %lx%s", entry->args[i],
143 i == entry->nb_args - 1 ? "" : ", ");
145 return TRACE_TYPE_PARTIAL_LINE;
148 ret = trace_seq_putc(s, ')');
150 return TRACE_TYPE_PARTIAL_LINE;
153 ret = trace_seq_putc(s, '\n');
155 return TRACE_TYPE_PARTIAL_LINE;
157 return TRACE_TYPE_HANDLED;
161 print_syscall_exit(struct trace_iterator *iter, int flags,
162 struct trace_event *event)
164 struct trace_seq *s = &iter->seq;
165 struct trace_entry *ent = iter->ent;
166 struct syscall_trace_exit *trace;
168 struct syscall_metadata *entry;
171 trace = (typeof(trace))ent;
173 entry = syscall_nr_to_meta(syscall);
176 trace_seq_printf(s, "\n");
177 return TRACE_TYPE_HANDLED;
180 if (entry->exit_event->event.type != ent->type) {
182 return TRACE_TYPE_UNHANDLED;
185 ret = trace_seq_printf(s, "%s -> 0x%lx\n", entry->name,
188 return TRACE_TYPE_PARTIAL_LINE;
190 return TRACE_TYPE_HANDLED;
193 extern char *__bad_type_size(void);
195 #define SYSCALL_FIELD(type, name) \
196 sizeof(type) != sizeof(trace.name) ? \
197 __bad_type_size() : \
198 #type, #name, offsetof(typeof(trace), name), \
199 sizeof(trace.name), is_signed_type(type)
202 int __set_enter_print_fmt(struct syscall_metadata *entry, char *buf, int len)
207 /* When len=0, we just calculate the needed length */
208 #define LEN_OR_ZERO (len ? len - pos : 0)
210 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
211 for (i = 0; i < entry->nb_args; i++) {
212 pos += snprintf(buf + pos, LEN_OR_ZERO, "%s: 0x%%0%zulx%s",
213 entry->args[i], sizeof(unsigned long),
214 i == entry->nb_args - 1 ? "" : ", ");
216 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
218 for (i = 0; i < entry->nb_args; i++) {
219 pos += snprintf(buf + pos, LEN_OR_ZERO,
220 ", ((unsigned long)(REC->%s))", entry->args[i]);
225 /* return the length of print_fmt */
229 static int set_syscall_print_fmt(struct ftrace_event_call *call)
233 struct syscall_metadata *entry = call->data;
235 if (entry->enter_event != call) {
236 call->print_fmt = "\"0x%lx\", REC->ret";
240 /* First: called with 0 length to calculate the needed length */
241 len = __set_enter_print_fmt(entry, NULL, 0);
243 print_fmt = kmalloc(len + 1, GFP_KERNEL);
247 /* Second: actually write the @print_fmt */
248 __set_enter_print_fmt(entry, print_fmt, len + 1);
249 call->print_fmt = print_fmt;
254 static void free_syscall_print_fmt(struct ftrace_event_call *call)
256 struct syscall_metadata *entry = call->data;
258 if (entry->enter_event == call)
259 kfree(call->print_fmt);
262 static int syscall_enter_define_fields(struct ftrace_event_call *call)
264 struct syscall_trace_enter trace;
265 struct syscall_metadata *meta = call->data;
268 int offset = offsetof(typeof(trace), args);
270 ret = trace_define_field(call, SYSCALL_FIELD(int, nr), FILTER_OTHER);
274 for (i = 0; i < meta->nb_args; i++) {
275 ret = trace_define_field(call, meta->types[i],
276 meta->args[i], offset,
277 sizeof(unsigned long), 0,
279 offset += sizeof(unsigned long);
285 static int syscall_exit_define_fields(struct ftrace_event_call *call)
287 struct syscall_trace_exit trace;
290 ret = trace_define_field(call, SYSCALL_FIELD(int, nr), FILTER_OTHER);
294 ret = trace_define_field(call, SYSCALL_FIELD(long, ret),
300 void ftrace_syscall_enter(void *ignore, struct pt_regs *regs, long id)
302 struct syscall_trace_enter *entry;
303 struct syscall_metadata *sys_data;
304 struct ring_buffer_event *event;
305 struct ring_buffer *buffer;
306 unsigned long irq_flags;
311 syscall_nr = syscall_get_nr(current, regs);
312 if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
314 if (!test_bit(syscall_nr, enabled_enter_syscalls))
317 sys_data = syscall_nr_to_meta(syscall_nr);
321 size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args;
323 local_save_flags(irq_flags);
324 pc = preempt_count();
326 event = trace_current_buffer_lock_reserve(&buffer,
327 sys_data->enter_event->event.type, size, irq_flags, pc);
331 entry = ring_buffer_event_data(event);
332 entry->nr = syscall_nr;
333 syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args);
335 if (!filter_current_check_discard(buffer, sys_data->enter_event,
337 trace_current_buffer_unlock_commit(buffer, event,
341 void ftrace_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
343 struct syscall_trace_exit *entry;
344 struct syscall_metadata *sys_data;
345 struct ring_buffer_event *event;
346 struct ring_buffer *buffer;
347 unsigned long irq_flags;
351 syscall_nr = syscall_get_nr(current, regs);
352 if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
354 if (!test_bit(syscall_nr, enabled_exit_syscalls))
357 sys_data = syscall_nr_to_meta(syscall_nr);
361 local_save_flags(irq_flags);
362 pc = preempt_count();
364 event = trace_current_buffer_lock_reserve(&buffer,
365 sys_data->exit_event->event.type, sizeof(*entry),
370 entry = ring_buffer_event_data(event);
371 entry->nr = syscall_nr;
372 entry->ret = syscall_get_return_value(current, regs);
374 if (!filter_current_check_discard(buffer, sys_data->exit_event,
376 trace_current_buffer_unlock_commit(buffer, event,
380 int reg_event_syscall_enter(struct ftrace_event_call *call)
385 num = ((struct syscall_metadata *)call->data)->syscall_nr;
386 if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
388 mutex_lock(&syscall_trace_lock);
389 if (!sys_refcount_enter)
390 ret = register_trace_sys_enter(ftrace_syscall_enter, NULL);
392 set_bit(num, enabled_enter_syscalls);
393 sys_refcount_enter++;
395 mutex_unlock(&syscall_trace_lock);
399 void unreg_event_syscall_enter(struct ftrace_event_call *call)
403 num = ((struct syscall_metadata *)call->data)->syscall_nr;
404 if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
406 mutex_lock(&syscall_trace_lock);
407 sys_refcount_enter--;
408 clear_bit(num, enabled_enter_syscalls);
409 if (!sys_refcount_enter)
410 unregister_trace_sys_enter(ftrace_syscall_enter, NULL);
411 mutex_unlock(&syscall_trace_lock);
414 int reg_event_syscall_exit(struct ftrace_event_call *call)
419 num = ((struct syscall_metadata *)call->data)->syscall_nr;
420 if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
422 mutex_lock(&syscall_trace_lock);
423 if (!sys_refcount_exit)
424 ret = register_trace_sys_exit(ftrace_syscall_exit, NULL);
426 set_bit(num, enabled_exit_syscalls);
429 mutex_unlock(&syscall_trace_lock);
433 void unreg_event_syscall_exit(struct ftrace_event_call *call)
437 num = ((struct syscall_metadata *)call->data)->syscall_nr;
438 if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
440 mutex_lock(&syscall_trace_lock);
442 clear_bit(num, enabled_exit_syscalls);
443 if (!sys_refcount_exit)
444 unregister_trace_sys_exit(ftrace_syscall_exit, NULL);
445 mutex_unlock(&syscall_trace_lock);
448 int init_syscall_trace(struct ftrace_event_call *call)
453 num = ((struct syscall_metadata *)call->data)->syscall_nr;
454 if (num < 0 || num >= NR_syscalls) {
455 pr_debug("syscall %s metadata not mapped, disabling ftrace event\n",
456 ((struct syscall_metadata *)call->data)->name);
460 if (set_syscall_print_fmt(call) < 0)
463 id = trace_event_raw_init(call);
466 free_syscall_print_fmt(call);
473 unsigned long __init __weak arch_syscall_addr(int nr)
475 return (unsigned long)sys_call_table[nr];
478 int __init init_ftrace_syscalls(void)
480 struct syscall_metadata *meta;
484 syscalls_metadata = kzalloc(sizeof(*syscalls_metadata) *
485 NR_syscalls, GFP_KERNEL);
486 if (!syscalls_metadata) {
491 for (i = 0; i < NR_syscalls; i++) {
492 addr = arch_syscall_addr(i);
493 meta = find_syscall_meta(addr);
497 meta->syscall_nr = i;
498 syscalls_metadata[i] = meta;
503 core_initcall(init_ftrace_syscalls);
505 #ifdef CONFIG_PERF_EVENTS
507 static DECLARE_BITMAP(enabled_perf_enter_syscalls, NR_syscalls);
508 static DECLARE_BITMAP(enabled_perf_exit_syscalls, NR_syscalls);
509 static int sys_perf_refcount_enter;
510 static int sys_perf_refcount_exit;
512 static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
514 struct syscall_metadata *sys_data;
515 struct syscall_trace_enter *rec;
516 struct hlist_head *head;
521 syscall_nr = syscall_get_nr(current, regs);
522 if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
524 if (!test_bit(syscall_nr, enabled_perf_enter_syscalls))
527 sys_data = syscall_nr_to_meta(syscall_nr);
531 /* get the size after alignment with the u32 buffer size field */
532 size = sizeof(unsigned long) * sys_data->nb_args + sizeof(*rec);
533 size = ALIGN(size + sizeof(u32), sizeof(u64));
536 if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
537 "perf buffer not large enough"))
540 rec = (struct syscall_trace_enter *)perf_trace_buf_prepare(size,
541 sys_data->enter_event->event.type, regs, &rctx);
545 rec->nr = syscall_nr;
546 syscall_get_arguments(current, regs, 0, sys_data->nb_args,
547 (unsigned long *)&rec->args);
549 head = this_cpu_ptr(sys_data->enter_event->perf_events);
550 perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head);
553 int perf_sysenter_enable(struct ftrace_event_call *call)
558 num = ((struct syscall_metadata *)call->data)->syscall_nr;
560 mutex_lock(&syscall_trace_lock);
561 if (!sys_perf_refcount_enter)
562 ret = register_trace_sys_enter(perf_syscall_enter, NULL);
564 pr_info("event trace: Could not activate"
565 "syscall entry trace point");
567 set_bit(num, enabled_perf_enter_syscalls);
568 sys_perf_refcount_enter++;
570 mutex_unlock(&syscall_trace_lock);
574 void perf_sysenter_disable(struct ftrace_event_call *call)
578 num = ((struct syscall_metadata *)call->data)->syscall_nr;
580 mutex_lock(&syscall_trace_lock);
581 sys_perf_refcount_enter--;
582 clear_bit(num, enabled_perf_enter_syscalls);
583 if (!sys_perf_refcount_enter)
584 unregister_trace_sys_enter(perf_syscall_enter, NULL);
585 mutex_unlock(&syscall_trace_lock);
588 static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
590 struct syscall_metadata *sys_data;
591 struct syscall_trace_exit *rec;
592 struct hlist_head *head;
597 syscall_nr = syscall_get_nr(current, regs);
598 if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
600 if (!test_bit(syscall_nr, enabled_perf_exit_syscalls))
603 sys_data = syscall_nr_to_meta(syscall_nr);
607 /* We can probably do that at build time */
608 size = ALIGN(sizeof(*rec) + sizeof(u32), sizeof(u64));
612 * Impossible, but be paranoid with the future
613 * How to put this check outside runtime?
615 if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
616 "exit event has grown above perf buffer size"))
619 rec = (struct syscall_trace_exit *)perf_trace_buf_prepare(size,
620 sys_data->exit_event->event.type, regs, &rctx);
624 rec->nr = syscall_nr;
625 rec->ret = syscall_get_return_value(current, regs);
627 head = this_cpu_ptr(sys_data->exit_event->perf_events);
628 perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head);
631 int perf_sysexit_enable(struct ftrace_event_call *call)
636 num = ((struct syscall_metadata *)call->data)->syscall_nr;
638 mutex_lock(&syscall_trace_lock);
639 if (!sys_perf_refcount_exit)
640 ret = register_trace_sys_exit(perf_syscall_exit, NULL);
642 pr_info("event trace: Could not activate"
643 "syscall exit trace point");
645 set_bit(num, enabled_perf_exit_syscalls);
646 sys_perf_refcount_exit++;
648 mutex_unlock(&syscall_trace_lock);
652 void perf_sysexit_disable(struct ftrace_event_call *call)
656 num = ((struct syscall_metadata *)call->data)->syscall_nr;
658 mutex_lock(&syscall_trace_lock);
659 sys_perf_refcount_exit--;
660 clear_bit(num, enabled_perf_exit_syscalls);
661 if (!sys_perf_refcount_exit)
662 unregister_trace_sys_exit(perf_syscall_exit, NULL);
663 mutex_unlock(&syscall_trace_lock);
666 #endif /* CONFIG_PERF_EVENTS */
668 static int syscall_enter_register(struct ftrace_event_call *event,
672 case TRACE_REG_REGISTER:
673 return reg_event_syscall_enter(event);
674 case TRACE_REG_UNREGISTER:
675 unreg_event_syscall_enter(event);
678 #ifdef CONFIG_PERF_EVENTS
679 case TRACE_REG_PERF_REGISTER:
680 return perf_sysenter_enable(event);
681 case TRACE_REG_PERF_UNREGISTER:
682 perf_sysenter_disable(event);
689 static int syscall_exit_register(struct ftrace_event_call *event,
693 case TRACE_REG_REGISTER:
694 return reg_event_syscall_exit(event);
695 case TRACE_REG_UNREGISTER:
696 unreg_event_syscall_exit(event);
699 #ifdef CONFIG_PERF_EVENTS
700 case TRACE_REG_PERF_REGISTER:
701 return perf_sysexit_enable(event);
702 case TRACE_REG_PERF_UNREGISTER:
703 perf_sysexit_disable(event);