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>
9 #include "trace_output.h"
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);
18 static int syscall_enter_register(struct ftrace_event_call *event,
20 static int syscall_exit_register(struct ftrace_event_call *event,
23 static int syscall_enter_define_fields(struct ftrace_event_call *call);
24 static int syscall_exit_define_fields(struct ftrace_event_call *call);
26 /* All syscall exit events have the same fields */
27 static LIST_HEAD(syscall_exit_fields);
29 static struct list_head *
30 syscall_get_enter_fields(struct ftrace_event_call *call)
32 struct syscall_metadata *entry = call->data;
34 return &entry->enter_fields;
37 static struct list_head *
38 syscall_get_exit_fields(struct ftrace_event_call *call)
40 return &syscall_exit_fields;
43 struct trace_event_functions enter_syscall_print_funcs = {
44 .trace = print_syscall_enter,
47 struct trace_event_functions exit_syscall_print_funcs = {
48 .trace = print_syscall_exit,
51 struct ftrace_event_class event_class_syscall_enter = {
53 .reg = syscall_enter_register,
54 .define_fields = syscall_enter_define_fields,
55 .get_fields = syscall_get_enter_fields,
56 .raw_init = init_syscall_trace,
59 struct ftrace_event_class event_class_syscall_exit = {
61 .reg = syscall_exit_register,
62 .define_fields = syscall_exit_define_fields,
63 .get_fields = syscall_get_exit_fields,
64 .raw_init = init_syscall_trace,
67 extern unsigned long __start_syscalls_metadata[];
68 extern unsigned long __stop_syscalls_metadata[];
70 static struct syscall_metadata **syscalls_metadata;
72 static struct syscall_metadata *find_syscall_meta(unsigned long syscall)
74 struct syscall_metadata *start;
75 struct syscall_metadata *stop;
76 char str[KSYM_SYMBOL_LEN];
79 start = (struct syscall_metadata *)__start_syscalls_metadata;
80 stop = (struct syscall_metadata *)__stop_syscalls_metadata;
81 kallsyms_lookup(syscall, NULL, NULL, NULL, str);
83 for ( ; start < stop; start++) {
85 * Only compare after the "sys" prefix. Archs that use
86 * syscall wrappers may have syscalls symbols aliases prefixed
87 * with "SyS" instead of "sys", leading to an unwanted
90 if (start->name && !strcmp(start->name + 3, str + 3))
96 static struct syscall_metadata *syscall_nr_to_meta(int nr)
98 if (!syscalls_metadata || nr >= NR_syscalls || nr < 0)
101 return syscalls_metadata[nr];
105 print_syscall_enter(struct trace_iterator *iter, int flags,
106 struct trace_event *event)
108 struct trace_seq *s = &iter->seq;
109 struct trace_entry *ent = iter->ent;
110 struct syscall_trace_enter *trace;
111 struct syscall_metadata *entry;
114 trace = (typeof(trace))ent;
116 entry = syscall_nr_to_meta(syscall);
121 if (entry->enter_event->event.type != ent->type) {
126 ret = trace_seq_printf(s, "%s(", entry->name);
128 return TRACE_TYPE_PARTIAL_LINE;
130 for (i = 0; i < entry->nb_args; i++) {
131 /* parameter types */
132 if (trace_flags & TRACE_ITER_VERBOSE) {
133 ret = trace_seq_printf(s, "%s ", entry->types[i]);
135 return TRACE_TYPE_PARTIAL_LINE;
137 /* parameter values */
138 ret = trace_seq_printf(s, "%s: %lx%s", entry->args[i],
140 i == entry->nb_args - 1 ? "" : ", ");
142 return TRACE_TYPE_PARTIAL_LINE;
145 ret = trace_seq_putc(s, ')');
147 return TRACE_TYPE_PARTIAL_LINE;
150 ret = trace_seq_putc(s, '\n');
152 return TRACE_TYPE_PARTIAL_LINE;
154 return TRACE_TYPE_HANDLED;
158 print_syscall_exit(struct trace_iterator *iter, int flags,
159 struct trace_event *event)
161 struct trace_seq *s = &iter->seq;
162 struct trace_entry *ent = iter->ent;
163 struct syscall_trace_exit *trace;
165 struct syscall_metadata *entry;
168 trace = (typeof(trace))ent;
170 entry = syscall_nr_to_meta(syscall);
173 trace_seq_printf(s, "\n");
174 return TRACE_TYPE_HANDLED;
177 if (entry->exit_event->event.type != ent->type) {
179 return TRACE_TYPE_UNHANDLED;
182 ret = trace_seq_printf(s, "%s -> 0x%lx\n", entry->name,
185 return TRACE_TYPE_PARTIAL_LINE;
187 return TRACE_TYPE_HANDLED;
190 extern char *__bad_type_size(void);
192 #define SYSCALL_FIELD(type, name) \
193 sizeof(type) != sizeof(trace.name) ? \
194 __bad_type_size() : \
195 #type, #name, offsetof(typeof(trace), name), \
196 sizeof(trace.name), is_signed_type(type)
199 int __set_enter_print_fmt(struct syscall_metadata *entry, char *buf, int len)
204 /* When len=0, we just calculate the needed length */
205 #define LEN_OR_ZERO (len ? len - pos : 0)
207 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
208 for (i = 0; i < entry->nb_args; i++) {
209 pos += snprintf(buf + pos, LEN_OR_ZERO, "%s: 0x%%0%zulx%s",
210 entry->args[i], sizeof(unsigned long),
211 i == entry->nb_args - 1 ? "" : ", ");
213 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
215 for (i = 0; i < entry->nb_args; i++) {
216 pos += snprintf(buf + pos, LEN_OR_ZERO,
217 ", ((unsigned long)(REC->%s))", entry->args[i]);
222 /* return the length of print_fmt */
226 static int set_syscall_print_fmt(struct ftrace_event_call *call)
230 struct syscall_metadata *entry = call->data;
232 if (entry->enter_event != call) {
233 call->print_fmt = "\"0x%lx\", REC->ret";
237 /* First: called with 0 length to calculate the needed length */
238 len = __set_enter_print_fmt(entry, NULL, 0);
240 print_fmt = kmalloc(len + 1, GFP_KERNEL);
244 /* Second: actually write the @print_fmt */
245 __set_enter_print_fmt(entry, print_fmt, len + 1);
246 call->print_fmt = print_fmt;
251 static void free_syscall_print_fmt(struct ftrace_event_call *call)
253 struct syscall_metadata *entry = call->data;
255 if (entry->enter_event == call)
256 kfree(call->print_fmt);
259 static int syscall_enter_define_fields(struct ftrace_event_call *call)
261 struct syscall_trace_enter trace;
262 struct syscall_metadata *meta = call->data;
265 int offset = offsetof(typeof(trace), args);
267 ret = trace_define_field(call, SYSCALL_FIELD(int, nr), FILTER_OTHER);
271 for (i = 0; i < meta->nb_args; i++) {
272 ret = trace_define_field(call, meta->types[i],
273 meta->args[i], offset,
274 sizeof(unsigned long), 0,
276 offset += sizeof(unsigned long);
282 static int syscall_exit_define_fields(struct ftrace_event_call *call)
284 struct syscall_trace_exit trace;
287 ret = trace_define_field(call, SYSCALL_FIELD(int, nr), FILTER_OTHER);
291 ret = trace_define_field(call, SYSCALL_FIELD(long, ret),
297 void ftrace_syscall_enter(void *ignore, struct pt_regs *regs, long id)
299 struct syscall_trace_enter *entry;
300 struct syscall_metadata *sys_data;
301 struct ring_buffer_event *event;
302 struct ring_buffer *buffer;
306 syscall_nr = syscall_get_nr(current, regs);
309 if (!test_bit(syscall_nr, enabled_enter_syscalls))
312 sys_data = syscall_nr_to_meta(syscall_nr);
316 size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args;
318 event = trace_current_buffer_lock_reserve(&buffer,
319 sys_data->enter_event->event.type, size, 0, 0);
323 entry = ring_buffer_event_data(event);
324 entry->nr = syscall_nr;
325 syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args);
327 if (!filter_current_check_discard(buffer, sys_data->enter_event,
329 trace_current_buffer_unlock_commit(buffer, event, 0, 0);
332 void ftrace_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
334 struct syscall_trace_exit *entry;
335 struct syscall_metadata *sys_data;
336 struct ring_buffer_event *event;
337 struct ring_buffer *buffer;
340 syscall_nr = syscall_get_nr(current, regs);
343 if (!test_bit(syscall_nr, enabled_exit_syscalls))
346 sys_data = syscall_nr_to_meta(syscall_nr);
350 event = trace_current_buffer_lock_reserve(&buffer,
351 sys_data->exit_event->event.type, sizeof(*entry), 0, 0);
355 entry = ring_buffer_event_data(event);
356 entry->nr = syscall_nr;
357 entry->ret = syscall_get_return_value(current, regs);
359 if (!filter_current_check_discard(buffer, sys_data->exit_event,
361 trace_current_buffer_unlock_commit(buffer, event, 0, 0);
364 int reg_event_syscall_enter(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);
373 if (!sys_refcount_enter)
374 ret = register_trace_sys_enter(ftrace_syscall_enter, NULL);
376 set_bit(num, enabled_enter_syscalls);
377 sys_refcount_enter++;
379 mutex_unlock(&syscall_trace_lock);
383 void unreg_event_syscall_enter(struct ftrace_event_call *call)
387 num = ((struct syscall_metadata *)call->data)->syscall_nr;
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, NULL);
395 mutex_unlock(&syscall_trace_lock);
398 int reg_event_syscall_exit(struct ftrace_event_call *call)
403 num = ((struct syscall_metadata *)call->data)->syscall_nr;
404 if (num < 0 || num >= NR_syscalls)
406 mutex_lock(&syscall_trace_lock);
407 if (!sys_refcount_exit)
408 ret = register_trace_sys_exit(ftrace_syscall_exit, NULL);
410 set_bit(num, enabled_exit_syscalls);
413 mutex_unlock(&syscall_trace_lock);
417 void unreg_event_syscall_exit(struct ftrace_event_call *call)
421 num = ((struct syscall_metadata *)call->data)->syscall_nr;
422 if (num < 0 || num >= NR_syscalls)
424 mutex_lock(&syscall_trace_lock);
426 clear_bit(num, enabled_exit_syscalls);
427 if (!sys_refcount_exit)
428 unregister_trace_sys_exit(ftrace_syscall_exit, NULL);
429 mutex_unlock(&syscall_trace_lock);
432 int init_syscall_trace(struct ftrace_event_call *call)
436 if (set_syscall_print_fmt(call) < 0)
439 id = trace_event_raw_init(call);
442 free_syscall_print_fmt(call);
449 unsigned long __init arch_syscall_addr(int nr)
451 return (unsigned long)sys_call_table[nr];
454 int __init init_ftrace_syscalls(void)
456 struct syscall_metadata *meta;
460 syscalls_metadata = kzalloc(sizeof(*syscalls_metadata) *
461 NR_syscalls, GFP_KERNEL);
462 if (!syscalls_metadata) {
467 for (i = 0; i < NR_syscalls; i++) {
468 addr = arch_syscall_addr(i);
469 meta = find_syscall_meta(addr);
473 meta->syscall_nr = i;
474 syscalls_metadata[i] = meta;
479 core_initcall(init_ftrace_syscalls);
481 #ifdef CONFIG_PERF_EVENTS
483 static DECLARE_BITMAP(enabled_perf_enter_syscalls, NR_syscalls);
484 static DECLARE_BITMAP(enabled_perf_exit_syscalls, NR_syscalls);
485 static int sys_perf_refcount_enter;
486 static int sys_perf_refcount_exit;
488 static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
490 struct syscall_metadata *sys_data;
491 struct syscall_trace_enter *rec;
492 struct hlist_head *head;
497 syscall_nr = syscall_get_nr(current, regs);
498 if (!test_bit(syscall_nr, enabled_perf_enter_syscalls))
501 sys_data = syscall_nr_to_meta(syscall_nr);
505 /* get the size after alignment with the u32 buffer size field */
506 size = sizeof(unsigned long) * sys_data->nb_args + sizeof(*rec);
507 size = ALIGN(size + sizeof(u32), sizeof(u64));
510 if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
511 "perf buffer not large enough"))
514 rec = (struct syscall_trace_enter *)perf_trace_buf_prepare(size,
515 sys_data->enter_event->event.type, regs, &rctx);
519 rec->nr = syscall_nr;
520 syscall_get_arguments(current, regs, 0, sys_data->nb_args,
521 (unsigned long *)&rec->args);
523 head = this_cpu_ptr(sys_data->enter_event->perf_events);
524 perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head);
527 int perf_sysenter_enable(struct ftrace_event_call *call)
532 num = ((struct syscall_metadata *)call->data)->syscall_nr;
534 mutex_lock(&syscall_trace_lock);
535 if (!sys_perf_refcount_enter)
536 ret = register_trace_sys_enter(perf_syscall_enter, NULL);
538 pr_info("event trace: Could not activate"
539 "syscall entry trace point");
541 set_bit(num, enabled_perf_enter_syscalls);
542 sys_perf_refcount_enter++;
544 mutex_unlock(&syscall_trace_lock);
548 void perf_sysenter_disable(struct ftrace_event_call *call)
552 num = ((struct syscall_metadata *)call->data)->syscall_nr;
554 mutex_lock(&syscall_trace_lock);
555 sys_perf_refcount_enter--;
556 clear_bit(num, enabled_perf_enter_syscalls);
557 if (!sys_perf_refcount_enter)
558 unregister_trace_sys_enter(perf_syscall_enter, NULL);
559 mutex_unlock(&syscall_trace_lock);
562 static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
564 struct syscall_metadata *sys_data;
565 struct syscall_trace_exit *rec;
566 struct hlist_head *head;
571 syscall_nr = syscall_get_nr(current, regs);
572 if (!test_bit(syscall_nr, enabled_perf_exit_syscalls))
575 sys_data = syscall_nr_to_meta(syscall_nr);
579 /* We can probably do that at build time */
580 size = ALIGN(sizeof(*rec) + sizeof(u32), sizeof(u64));
584 * Impossible, but be paranoid with the future
585 * How to put this check outside runtime?
587 if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
588 "exit event has grown above perf buffer size"))
591 rec = (struct syscall_trace_exit *)perf_trace_buf_prepare(size,
592 sys_data->exit_event->event.type, regs, &rctx);
596 rec->nr = syscall_nr;
597 rec->ret = syscall_get_return_value(current, regs);
599 head = this_cpu_ptr(sys_data->exit_event->perf_events);
600 perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head);
603 int perf_sysexit_enable(struct ftrace_event_call *call)
608 num = ((struct syscall_metadata *)call->data)->syscall_nr;
610 mutex_lock(&syscall_trace_lock);
611 if (!sys_perf_refcount_exit)
612 ret = register_trace_sys_exit(perf_syscall_exit, NULL);
614 pr_info("event trace: Could not activate"
615 "syscall exit trace point");
617 set_bit(num, enabled_perf_exit_syscalls);
618 sys_perf_refcount_exit++;
620 mutex_unlock(&syscall_trace_lock);
624 void perf_sysexit_disable(struct ftrace_event_call *call)
628 num = ((struct syscall_metadata *)call->data)->syscall_nr;
630 mutex_lock(&syscall_trace_lock);
631 sys_perf_refcount_exit--;
632 clear_bit(num, enabled_perf_exit_syscalls);
633 if (!sys_perf_refcount_exit)
634 unregister_trace_sys_exit(perf_syscall_exit, NULL);
635 mutex_unlock(&syscall_trace_lock);
638 #endif /* CONFIG_PERF_EVENTS */
640 static int syscall_enter_register(struct ftrace_event_call *event,
644 case TRACE_REG_REGISTER:
645 return reg_event_syscall_enter(event);
646 case TRACE_REG_UNREGISTER:
647 unreg_event_syscall_enter(event);
650 #ifdef CONFIG_PERF_EVENTS
651 case TRACE_REG_PERF_REGISTER:
652 return perf_sysenter_enable(event);
653 case TRACE_REG_PERF_UNREGISTER:
654 perf_sysenter_disable(event);
661 static int syscall_exit_register(struct ftrace_event_call *event,
665 case TRACE_REG_REGISTER:
666 return reg_event_syscall_exit(event);
667 case TRACE_REG_UNREGISTER:
668 unreg_event_syscall_exit(event);
671 #ifdef CONFIG_PERF_EVENTS
672 case TRACE_REG_PERF_REGISTER:
673 return perf_sysexit_enable(event);
674 case TRACE_REG_PERF_UNREGISTER:
675 perf_sysexit_disable(event);