powerpc/powernv: Report size of OPAL memcons log
[linux/fpc-iii.git] / kernel / trace / trace_syscalls.c
blob5e10395da88ecc0fe213b77510355119ab5f7648
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"
12 #include "trace.h"
14 static DEFINE_MUTEX(syscall_trace_lock);
16 static int syscall_enter_register(struct trace_event_call *event,
17 enum trace_reg type, void *data);
18 static int syscall_exit_register(struct trace_event_call *event,
19 enum trace_reg type, void *data);
21 static struct list_head *
22 syscall_get_enter_fields(struct trace_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
41 * mismatch.
43 return !strcmp(sym + 3, name + 3);
45 #endif
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.
53 * *cough*x86*cough*
55 * In such a case, instead of reporting the wrong syscalls,
56 * simply ignore them.
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.
63 static int
64 trace_get_syscall_nr(struct task_struct *task, struct pt_regs *regs)
66 if (unlikely(arch_trace_is_compat_syscall(regs)))
67 return -1;
69 return syscall_get_nr(task, regs);
71 #else
72 static inline int
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"))
92 return NULL;
94 for ( ; start < stop; start++) {
95 if ((*start)->name && arch_syscall_match_sym_name(str, (*start)->name))
96 return *start;
98 return NULL;
101 static struct syscall_metadata *syscall_nr_to_meta(int nr)
103 if (!syscalls_metadata || nr >= NR_syscalls || nr < 0)
104 return NULL;
106 return syscalls_metadata[nr];
109 const char *get_syscall_name(int syscall)
111 struct syscall_metadata *entry;
113 entry = syscall_nr_to_meta(syscall);
114 if (!entry)
115 return NULL;
117 return entry->name;
120 static enum print_line_t
121 print_syscall_enter(struct trace_iterator *iter, int flags,
122 struct trace_event *event)
124 struct trace_array *tr = iter->tr;
125 struct trace_seq *s = &iter->seq;
126 struct trace_entry *ent = iter->ent;
127 struct syscall_trace_enter *trace;
128 struct syscall_metadata *entry;
129 int i, syscall;
131 trace = (typeof(trace))ent;
132 syscall = trace->nr;
133 entry = syscall_nr_to_meta(syscall);
135 if (!entry)
136 goto end;
138 if (entry->enter_event->event.type != ent->type) {
139 WARN_ON_ONCE(1);
140 goto end;
143 trace_seq_printf(s, "%s(", entry->name);
145 for (i = 0; i < entry->nb_args; i++) {
147 if (trace_seq_has_overflowed(s))
148 goto end;
150 /* parameter types */
151 if (tr->trace_flags & TRACE_ITER_VERBOSE)
152 trace_seq_printf(s, "%s ", entry->types[i]);
154 /* parameter values */
155 trace_seq_printf(s, "%s: %lx%s", entry->args[i],
156 trace->args[i],
157 i == entry->nb_args - 1 ? "" : ", ");
160 trace_seq_putc(s, ')');
161 end:
162 trace_seq_putc(s, '\n');
164 return trace_handle_return(s);
167 static enum print_line_t
168 print_syscall_exit(struct trace_iterator *iter, int flags,
169 struct trace_event *event)
171 struct trace_seq *s = &iter->seq;
172 struct trace_entry *ent = iter->ent;
173 struct syscall_trace_exit *trace;
174 int syscall;
175 struct syscall_metadata *entry;
177 trace = (typeof(trace))ent;
178 syscall = trace->nr;
179 entry = syscall_nr_to_meta(syscall);
181 if (!entry) {
182 trace_seq_putc(s, '\n');
183 goto out;
186 if (entry->exit_event->event.type != ent->type) {
187 WARN_ON_ONCE(1);
188 return TRACE_TYPE_UNHANDLED;
191 trace_seq_printf(s, "%s -> 0x%lx\n", entry->name,
192 trace->ret);
194 out:
195 return trace_handle_return(s);
198 extern char *__bad_type_size(void);
200 #define SYSCALL_FIELD(type, field, name) \
201 sizeof(type) != sizeof(trace.field) ? \
202 __bad_type_size() : \
203 #type, #name, offsetof(typeof(trace), field), \
204 sizeof(trace.field), is_signed_type(type)
206 static int __init
207 __set_enter_print_fmt(struct syscall_metadata *entry, char *buf, int len)
209 int i;
210 int pos = 0;
212 /* When len=0, we just calculate the needed length */
213 #define LEN_OR_ZERO (len ? len - pos : 0)
215 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
216 for (i = 0; i < entry->nb_args; i++) {
217 pos += snprintf(buf + pos, LEN_OR_ZERO, "%s: 0x%%0%zulx%s",
218 entry->args[i], sizeof(unsigned long),
219 i == entry->nb_args - 1 ? "" : ", ");
221 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
223 for (i = 0; i < entry->nb_args; i++) {
224 pos += snprintf(buf + pos, LEN_OR_ZERO,
225 ", ((unsigned long)(REC->%s))", entry->args[i]);
228 #undef LEN_OR_ZERO
230 /* return the length of print_fmt */
231 return pos;
234 static int __init set_syscall_print_fmt(struct trace_event_call *call)
236 char *print_fmt;
237 int len;
238 struct syscall_metadata *entry = call->data;
240 if (entry->enter_event != call) {
241 call->print_fmt = "\"0x%lx\", REC->ret";
242 return 0;
245 /* First: called with 0 length to calculate the needed length */
246 len = __set_enter_print_fmt(entry, NULL, 0);
248 print_fmt = kmalloc(len + 1, GFP_KERNEL);
249 if (!print_fmt)
250 return -ENOMEM;
252 /* Second: actually write the @print_fmt */
253 __set_enter_print_fmt(entry, print_fmt, len + 1);
254 call->print_fmt = print_fmt;
256 return 0;
259 static void __init free_syscall_print_fmt(struct trace_event_call *call)
261 struct syscall_metadata *entry = call->data;
263 if (entry->enter_event == call)
264 kfree(call->print_fmt);
267 static int __init syscall_enter_define_fields(struct trace_event_call *call)
269 struct syscall_trace_enter trace;
270 struct syscall_metadata *meta = call->data;
271 int ret;
272 int i;
273 int offset = offsetof(typeof(trace), args);
275 ret = trace_define_field(call, SYSCALL_FIELD(int, nr, __syscall_nr),
276 FILTER_OTHER);
277 if (ret)
278 return ret;
280 for (i = 0; i < meta->nb_args; i++) {
281 ret = trace_define_field(call, meta->types[i],
282 meta->args[i], offset,
283 sizeof(unsigned long), 0,
284 FILTER_OTHER);
285 offset += sizeof(unsigned long);
288 return ret;
291 static int __init syscall_exit_define_fields(struct trace_event_call *call)
293 struct syscall_trace_exit trace;
294 int ret;
296 ret = trace_define_field(call, SYSCALL_FIELD(int, nr, __syscall_nr),
297 FILTER_OTHER);
298 if (ret)
299 return ret;
301 ret = trace_define_field(call, SYSCALL_FIELD(long, ret, ret),
302 FILTER_OTHER);
304 return ret;
307 static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
309 struct trace_array *tr = data;
310 struct trace_event_file *trace_file;
311 struct syscall_trace_enter *entry;
312 struct syscall_metadata *sys_data;
313 struct ring_buffer_event *event;
314 struct ring_buffer *buffer;
315 unsigned long irq_flags;
316 int pc;
317 int syscall_nr;
318 int size;
320 syscall_nr = trace_get_syscall_nr(current, regs);
321 if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
322 return;
324 /* Here we're inside tp handler's rcu_read_lock_sched (__DO_TRACE) */
325 trace_file = rcu_dereference_sched(tr->enter_syscall_files[syscall_nr]);
326 if (!trace_file)
327 return;
329 if (trace_trigger_soft_disabled(trace_file))
330 return;
332 sys_data = syscall_nr_to_meta(syscall_nr);
333 if (!sys_data)
334 return;
336 size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args;
338 local_save_flags(irq_flags);
339 pc = preempt_count();
341 buffer = tr->trace_buffer.buffer;
342 event = trace_buffer_lock_reserve(buffer,
343 sys_data->enter_event->event.type, size, irq_flags, pc);
344 if (!event)
345 return;
347 entry = ring_buffer_event_data(event);
348 entry->nr = syscall_nr;
349 syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args);
351 event_trigger_unlock_commit(trace_file, buffer, event, entry,
352 irq_flags, pc);
355 static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret)
357 struct trace_array *tr = data;
358 struct trace_event_file *trace_file;
359 struct syscall_trace_exit *entry;
360 struct syscall_metadata *sys_data;
361 struct ring_buffer_event *event;
362 struct ring_buffer *buffer;
363 unsigned long irq_flags;
364 int pc;
365 int syscall_nr;
367 syscall_nr = trace_get_syscall_nr(current, regs);
368 if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
369 return;
371 /* Here we're inside tp handler's rcu_read_lock_sched (__DO_TRACE()) */
372 trace_file = rcu_dereference_sched(tr->exit_syscall_files[syscall_nr]);
373 if (!trace_file)
374 return;
376 if (trace_trigger_soft_disabled(trace_file))
377 return;
379 sys_data = syscall_nr_to_meta(syscall_nr);
380 if (!sys_data)
381 return;
383 local_save_flags(irq_flags);
384 pc = preempt_count();
386 buffer = tr->trace_buffer.buffer;
387 event = trace_buffer_lock_reserve(buffer,
388 sys_data->exit_event->event.type, sizeof(*entry),
389 irq_flags, pc);
390 if (!event)
391 return;
393 entry = ring_buffer_event_data(event);
394 entry->nr = syscall_nr;
395 entry->ret = syscall_get_return_value(current, regs);
397 event_trigger_unlock_commit(trace_file, buffer, event, entry,
398 irq_flags, pc);
401 static int reg_event_syscall_enter(struct trace_event_file *file,
402 struct trace_event_call *call)
404 struct trace_array *tr = file->tr;
405 int ret = 0;
406 int num;
408 num = ((struct syscall_metadata *)call->data)->syscall_nr;
409 if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
410 return -ENOSYS;
411 mutex_lock(&syscall_trace_lock);
412 if (!tr->sys_refcount_enter)
413 ret = register_trace_sys_enter(ftrace_syscall_enter, tr);
414 if (!ret) {
415 rcu_assign_pointer(tr->enter_syscall_files[num], file);
416 tr->sys_refcount_enter++;
418 mutex_unlock(&syscall_trace_lock);
419 return ret;
422 static void unreg_event_syscall_enter(struct trace_event_file *file,
423 struct trace_event_call *call)
425 struct trace_array *tr = file->tr;
426 int num;
428 num = ((struct syscall_metadata *)call->data)->syscall_nr;
429 if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
430 return;
431 mutex_lock(&syscall_trace_lock);
432 tr->sys_refcount_enter--;
433 RCU_INIT_POINTER(tr->enter_syscall_files[num], NULL);
434 if (!tr->sys_refcount_enter)
435 unregister_trace_sys_enter(ftrace_syscall_enter, tr);
436 mutex_unlock(&syscall_trace_lock);
439 static int reg_event_syscall_exit(struct trace_event_file *file,
440 struct trace_event_call *call)
442 struct trace_array *tr = file->tr;
443 int ret = 0;
444 int num;
446 num = ((struct syscall_metadata *)call->data)->syscall_nr;
447 if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
448 return -ENOSYS;
449 mutex_lock(&syscall_trace_lock);
450 if (!tr->sys_refcount_exit)
451 ret = register_trace_sys_exit(ftrace_syscall_exit, tr);
452 if (!ret) {
453 rcu_assign_pointer(tr->exit_syscall_files[num], file);
454 tr->sys_refcount_exit++;
456 mutex_unlock(&syscall_trace_lock);
457 return ret;
460 static void unreg_event_syscall_exit(struct trace_event_file *file,
461 struct trace_event_call *call)
463 struct trace_array *tr = file->tr;
464 int num;
466 num = ((struct syscall_metadata *)call->data)->syscall_nr;
467 if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
468 return;
469 mutex_lock(&syscall_trace_lock);
470 tr->sys_refcount_exit--;
471 RCU_INIT_POINTER(tr->exit_syscall_files[num], NULL);
472 if (!tr->sys_refcount_exit)
473 unregister_trace_sys_exit(ftrace_syscall_exit, tr);
474 mutex_unlock(&syscall_trace_lock);
477 static int __init init_syscall_trace(struct trace_event_call *call)
479 int id;
480 int num;
482 num = ((struct syscall_metadata *)call->data)->syscall_nr;
483 if (num < 0 || num >= NR_syscalls) {
484 pr_debug("syscall %s metadata not mapped, disabling ftrace event\n",
485 ((struct syscall_metadata *)call->data)->name);
486 return -ENOSYS;
489 if (set_syscall_print_fmt(call) < 0)
490 return -ENOMEM;
492 id = trace_event_raw_init(call);
494 if (id < 0) {
495 free_syscall_print_fmt(call);
496 return id;
499 return id;
502 struct trace_event_functions enter_syscall_print_funcs = {
503 .trace = print_syscall_enter,
506 struct trace_event_functions exit_syscall_print_funcs = {
507 .trace = print_syscall_exit,
510 struct trace_event_class __refdata event_class_syscall_enter = {
511 .system = "syscalls",
512 .reg = syscall_enter_register,
513 .define_fields = syscall_enter_define_fields,
514 .get_fields = syscall_get_enter_fields,
515 .raw_init = init_syscall_trace,
518 struct trace_event_class __refdata event_class_syscall_exit = {
519 .system = "syscalls",
520 .reg = syscall_exit_register,
521 .define_fields = syscall_exit_define_fields,
522 .fields = LIST_HEAD_INIT(event_class_syscall_exit.fields),
523 .raw_init = init_syscall_trace,
526 unsigned long __init __weak arch_syscall_addr(int nr)
528 return (unsigned long)sys_call_table[nr];
531 void __init init_ftrace_syscalls(void)
533 struct syscall_metadata *meta;
534 unsigned long addr;
535 int i;
537 syscalls_metadata = kcalloc(NR_syscalls, sizeof(*syscalls_metadata),
538 GFP_KERNEL);
539 if (!syscalls_metadata) {
540 WARN_ON(1);
541 return;
544 for (i = 0; i < NR_syscalls; i++) {
545 addr = arch_syscall_addr(i);
546 meta = find_syscall_meta(addr);
547 if (!meta)
548 continue;
550 meta->syscall_nr = i;
551 syscalls_metadata[i] = meta;
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;
567 int syscall_nr;
568 int rctx;
569 int size;
571 syscall_nr = trace_get_syscall_nr(current, regs);
572 if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
573 return;
574 if (!test_bit(syscall_nr, enabled_perf_enter_syscalls))
575 return;
577 sys_data = syscall_nr_to_meta(syscall_nr);
578 if (!sys_data)
579 return;
581 head = this_cpu_ptr(sys_data->enter_event->perf_events);
582 if (hlist_empty(head))
583 return;
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));
588 size -= sizeof(u32);
590 rec = perf_trace_buf_alloc(size, NULL, &rctx);
591 if (!rec)
592 return;
594 rec->nr = syscall_nr;
595 syscall_get_arguments(current, regs, 0, sys_data->nb_args,
596 (unsigned long *)&rec->args);
597 perf_trace_buf_submit(rec, size, rctx,
598 sys_data->enter_event->event.type, 1, regs,
599 head, NULL);
602 static int perf_sysenter_enable(struct trace_event_call *call)
604 int ret = 0;
605 int num;
607 num = ((struct syscall_metadata *)call->data)->syscall_nr;
609 mutex_lock(&syscall_trace_lock);
610 if (!sys_perf_refcount_enter)
611 ret = register_trace_sys_enter(perf_syscall_enter, NULL);
612 if (ret) {
613 pr_info("event trace: Could not activate syscall entry trace point");
614 } else {
615 set_bit(num, enabled_perf_enter_syscalls);
616 sys_perf_refcount_enter++;
618 mutex_unlock(&syscall_trace_lock);
619 return ret;
622 static void perf_sysenter_disable(struct trace_event_call *call)
624 int num;
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;
641 int syscall_nr;
642 int rctx;
643 int size;
645 syscall_nr = trace_get_syscall_nr(current, regs);
646 if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
647 return;
648 if (!test_bit(syscall_nr, enabled_perf_exit_syscalls))
649 return;
651 sys_data = syscall_nr_to_meta(syscall_nr);
652 if (!sys_data)
653 return;
655 head = this_cpu_ptr(sys_data->exit_event->perf_events);
656 if (hlist_empty(head))
657 return;
659 /* We can probably do that at build time */
660 size = ALIGN(sizeof(*rec) + sizeof(u32), sizeof(u64));
661 size -= sizeof(u32);
663 rec = perf_trace_buf_alloc(size, NULL, &rctx);
664 if (!rec)
665 return;
667 rec->nr = syscall_nr;
668 rec->ret = syscall_get_return_value(current, regs);
669 perf_trace_buf_submit(rec, size, rctx, sys_data->exit_event->event.type,
670 1, regs, head, NULL);
673 static int perf_sysexit_enable(struct trace_event_call *call)
675 int ret = 0;
676 int num;
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);
683 if (ret) {
684 pr_info("event trace: Could not activate syscall exit trace point");
685 } else {
686 set_bit(num, enabled_perf_exit_syscalls);
687 sys_perf_refcount_exit++;
689 mutex_unlock(&syscall_trace_lock);
690 return ret;
693 static void perf_sysexit_disable(struct trace_event_call *call)
695 int num;
697 num = ((struct syscall_metadata *)call->data)->syscall_nr;
699 mutex_lock(&syscall_trace_lock);
700 sys_perf_refcount_exit--;
701 clear_bit(num, enabled_perf_exit_syscalls);
702 if (!sys_perf_refcount_exit)
703 unregister_trace_sys_exit(perf_syscall_exit, NULL);
704 mutex_unlock(&syscall_trace_lock);
707 #endif /* CONFIG_PERF_EVENTS */
709 static int syscall_enter_register(struct trace_event_call *event,
710 enum trace_reg type, void *data)
712 struct trace_event_file *file = data;
714 switch (type) {
715 case TRACE_REG_REGISTER:
716 return reg_event_syscall_enter(file, event);
717 case TRACE_REG_UNREGISTER:
718 unreg_event_syscall_enter(file, event);
719 return 0;
721 #ifdef CONFIG_PERF_EVENTS
722 case TRACE_REG_PERF_REGISTER:
723 return perf_sysenter_enable(event);
724 case TRACE_REG_PERF_UNREGISTER:
725 perf_sysenter_disable(event);
726 return 0;
727 case TRACE_REG_PERF_OPEN:
728 case TRACE_REG_PERF_CLOSE:
729 case TRACE_REG_PERF_ADD:
730 case TRACE_REG_PERF_DEL:
731 return 0;
732 #endif
734 return 0;
737 static int syscall_exit_register(struct trace_event_call *event,
738 enum trace_reg type, void *data)
740 struct trace_event_file *file = data;
742 switch (type) {
743 case TRACE_REG_REGISTER:
744 return reg_event_syscall_exit(file, event);
745 case TRACE_REG_UNREGISTER:
746 unreg_event_syscall_exit(file, event);
747 return 0;
749 #ifdef CONFIG_PERF_EVENTS
750 case TRACE_REG_PERF_REGISTER:
751 return perf_sysexit_enable(event);
752 case TRACE_REG_PERF_UNREGISTER:
753 perf_sysexit_disable(event);
754 return 0;
755 case TRACE_REG_PERF_OPEN:
756 case TRACE_REG_PERF_CLOSE:
757 case TRACE_REG_PERF_ADD:
758 case TRACE_REG_PERF_DEL:
759 return 0;
760 #endif
762 return 0;