2 * ring buffer based function tracer
4 * Copyright (C) 2007-2012 Steven Rostedt <srostedt@redhat.com>
5 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
7 * Originally taken from the RT patch by:
8 * Arnaldo Carvalho de Melo <acme@redhat.com>
10 * Based on code from the latency_tracer, that is:
11 * Copyright (C) 2004-2006 Ingo Molnar
12 * Copyright (C) 2004 Nadia Yvette Chambers
14 #include <linux/ring_buffer.h>
15 #include <generated/utsrelease.h>
16 #include <linux/stacktrace.h>
17 #include <linux/writeback.h>
18 #include <linux/kallsyms.h>
19 #include <linux/seq_file.h>
20 #include <linux/notifier.h>
21 #include <linux/irqflags.h>
22 #include <linux/debugfs.h>
23 #include <linux/pagemap.h>
24 #include <linux/hardirq.h>
25 #include <linux/linkage.h>
26 #include <linux/uaccess.h>
27 #include <linux/kprobes.h>
28 #include <linux/ftrace.h>
29 #include <linux/module.h>
30 #include <linux/percpu.h>
31 #include <linux/splice.h>
32 #include <linux/kdebug.h>
33 #include <linux/string.h>
34 #include <linux/rwsem.h>
35 #include <linux/slab.h>
36 #include <linux/ctype.h>
37 #include <linux/init.h>
38 #include <linux/poll.h>
39 #include <linux/nmi.h>
41 #include <linux/sched/rt.h>
44 #include "trace_output.h"
47 * On boot up, the ring buffer is set to the minimum size, so that
48 * we do not waste memory on systems that are not using tracing.
50 bool ring_buffer_expanded;
53 * We need to change this state when a selftest is running.
54 * A selftest will lurk into the ring-buffer to count the
55 * entries inserted during the selftest although some concurrent
56 * insertions into the ring-buffer such as trace_printk could occurred
57 * at the same time, giving false positive or negative results.
59 static bool __read_mostly tracing_selftest_running;
62 * If a tracer is running, we do not want to run SELFTEST.
64 bool __read_mostly tracing_selftest_disabled;
66 /* For tracers that don't implement custom flags */
67 static struct tracer_opt dummy_tracer_opt[] = {
71 static struct tracer_flags dummy_tracer_flags = {
73 .opts = dummy_tracer_opt
76 static int dummy_set_flag(u32 old_flags, u32 bit, int set)
82 * To prevent the comm cache from being overwritten when no
83 * tracing is active, only save the comm when a trace event
86 static DEFINE_PER_CPU(bool, trace_cmdline_save);
89 * Kill all tracing for good (never come back).
90 * It is initialized to 1 but will turn to zero if the initialization
91 * of the tracer is successful. But that is the only place that sets
94 static int tracing_disabled = 1;
96 DEFINE_PER_CPU(int, ftrace_cpu_disabled);
98 cpumask_var_t __read_mostly tracing_buffer_mask;
101 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
103 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
104 * is set, then ftrace_dump is called. This will output the contents
105 * of the ftrace buffers to the console. This is very useful for
106 * capturing traces that lead to crashes and outputing it to a
109 * It is default off, but you can enable it with either specifying
110 * "ftrace_dump_on_oops" in the kernel command line, or setting
111 * /proc/sys/kernel/ftrace_dump_on_oops
112 * Set 1 if you want to dump buffers of all CPUs
113 * Set 2 if you want to dump the buffer of the CPU that triggered oops
116 enum ftrace_dump_mode ftrace_dump_on_oops;
118 static int tracing_set_tracer(const char *buf);
120 #define MAX_TRACER_SIZE 100
121 static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata;
122 static char *default_bootup_tracer;
124 static bool allocate_snapshot;
126 static int __init set_cmdline_ftrace(char *str)
128 strlcpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
129 default_bootup_tracer = bootup_tracer_buf;
130 /* We are using ftrace early, expand it */
131 ring_buffer_expanded = true;
134 __setup("ftrace=", set_cmdline_ftrace);
136 static int __init set_ftrace_dump_on_oops(char *str)
138 if (*str++ != '=' || !*str) {
139 ftrace_dump_on_oops = DUMP_ALL;
143 if (!strcmp("orig_cpu", str)) {
144 ftrace_dump_on_oops = DUMP_ORIG;
150 __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
152 static int __init boot_alloc_snapshot(char *str)
154 allocate_snapshot = true;
155 /* We also need the main ring buffer expanded */
156 ring_buffer_expanded = true;
159 __setup("alloc_snapshot", boot_alloc_snapshot);
162 static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata;
163 static char *trace_boot_options __initdata;
165 static int __init set_trace_boot_options(char *str)
167 strlcpy(trace_boot_options_buf, str, MAX_TRACER_SIZE);
168 trace_boot_options = trace_boot_options_buf;
171 __setup("trace_options=", set_trace_boot_options);
173 unsigned long long ns2usecs(cycle_t nsec)
181 * The global_trace is the descriptor that holds the tracing
182 * buffers for the live tracing. For each CPU, it contains
183 * a link list of pages that will store trace entries. The
184 * page descriptor of the pages in the memory is used to hold
185 * the link list by linking the lru item in the page descriptor
186 * to each of the pages in the buffer per CPU.
188 * For each active CPU there is a data field that holds the
189 * pages for the buffer for that CPU. Each CPU has the same number
190 * of pages allocated for its buffer.
192 static struct trace_array global_trace;
194 LIST_HEAD(ftrace_trace_arrays);
196 int trace_array_get(struct trace_array *this_tr)
198 struct trace_array *tr;
201 mutex_lock(&trace_types_lock);
202 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
209 mutex_unlock(&trace_types_lock);
214 static void __trace_array_put(struct trace_array *this_tr)
216 WARN_ON(!this_tr->ref);
220 void trace_array_put(struct trace_array *this_tr)
222 mutex_lock(&trace_types_lock);
223 __trace_array_put(this_tr);
224 mutex_unlock(&trace_types_lock);
227 int filter_current_check_discard(struct ring_buffer *buffer,
228 struct ftrace_event_call *call, void *rec,
229 struct ring_buffer_event *event)
231 return filter_check_discard(call, rec, buffer, event);
233 EXPORT_SYMBOL_GPL(filter_current_check_discard);
235 cycle_t buffer_ftrace_now(struct trace_buffer *buf, int cpu)
239 /* Early boot up does not have a buffer yet */
241 return trace_clock_local();
243 ts = ring_buffer_time_stamp(buf->buffer, cpu);
244 ring_buffer_normalize_time_stamp(buf->buffer, cpu, &ts);
249 cycle_t ftrace_now(int cpu)
251 return buffer_ftrace_now(&global_trace.trace_buffer, cpu);
255 * tracing_is_enabled - Show if global_trace has been disabled
257 * Shows if the global trace has been enabled or not. It uses the
258 * mirror flag "buffer_disabled" to be used in fast paths such as for
259 * the irqsoff tracer. But it may be inaccurate due to races. If you
260 * need to know the accurate state, use tracing_is_on() which is a little
261 * slower, but accurate.
263 int tracing_is_enabled(void)
266 * For quick access (irqsoff uses this in fast path), just
267 * return the mirror variable of the state of the ring buffer.
268 * It's a little racy, but we don't really care.
271 return !global_trace.buffer_disabled;
275 * trace_buf_size is the size in bytes that is allocated
276 * for a buffer. Note, the number of bytes is always rounded
279 * This number is purposely set to a low number of 16384.
280 * If the dump on oops happens, it will be much appreciated
281 * to not have to wait for all that output. Anyway this can be
282 * boot time and run time configurable.
284 #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
286 static unsigned long trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
288 /* trace_types holds a link list of available tracers. */
289 static struct tracer *trace_types __read_mostly;
292 * trace_types_lock is used to protect the trace_types list.
294 DEFINE_MUTEX(trace_types_lock);
297 * serialize the access of the ring buffer
299 * ring buffer serializes readers, but it is low level protection.
300 * The validity of the events (which returns by ring_buffer_peek() ..etc)
301 * are not protected by ring buffer.
303 * The content of events may become garbage if we allow other process consumes
304 * these events concurrently:
305 * A) the page of the consumed events may become a normal page
306 * (not reader page) in ring buffer, and this page will be rewrited
307 * by events producer.
308 * B) The page of the consumed events may become a page for splice_read,
309 * and this page will be returned to system.
311 * These primitives allow multi process access to different cpu ring buffer
314 * These primitives don't distinguish read-only and read-consume access.
315 * Multi read-only access are also serialized.
319 static DECLARE_RWSEM(all_cpu_access_lock);
320 static DEFINE_PER_CPU(struct mutex, cpu_access_lock);
322 static inline void trace_access_lock(int cpu)
324 if (cpu == RING_BUFFER_ALL_CPUS) {
325 /* gain it for accessing the whole ring buffer. */
326 down_write(&all_cpu_access_lock);
328 /* gain it for accessing a cpu ring buffer. */
330 /* Firstly block other trace_access_lock(RING_BUFFER_ALL_CPUS). */
331 down_read(&all_cpu_access_lock);
333 /* Secondly block other access to this @cpu ring buffer. */
334 mutex_lock(&per_cpu(cpu_access_lock, cpu));
338 static inline void trace_access_unlock(int cpu)
340 if (cpu == RING_BUFFER_ALL_CPUS) {
341 up_write(&all_cpu_access_lock);
343 mutex_unlock(&per_cpu(cpu_access_lock, cpu));
344 up_read(&all_cpu_access_lock);
348 static inline void trace_access_lock_init(void)
352 for_each_possible_cpu(cpu)
353 mutex_init(&per_cpu(cpu_access_lock, cpu));
358 static DEFINE_MUTEX(access_lock);
360 static inline void trace_access_lock(int cpu)
363 mutex_lock(&access_lock);
366 static inline void trace_access_unlock(int cpu)
369 mutex_unlock(&access_lock);
372 static inline void trace_access_lock_init(void)
378 /* trace_flags holds trace_options default values */
379 unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK |
380 TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | TRACE_ITER_SLEEP_TIME |
381 TRACE_ITER_GRAPH_TIME | TRACE_ITER_RECORD_CMD | TRACE_ITER_OVERWRITE |
382 TRACE_ITER_IRQ_INFO | TRACE_ITER_MARKERS | TRACE_ITER_FUNCTION;
384 void tracer_tracing_on(struct trace_array *tr)
386 if (tr->trace_buffer.buffer)
387 ring_buffer_record_on(tr->trace_buffer.buffer);
389 * This flag is looked at when buffers haven't been allocated
390 * yet, or by some tracers (like irqsoff), that just want to
391 * know if the ring buffer has been disabled, but it can handle
392 * races of where it gets disabled but we still do a record.
393 * As the check is in the fast path of the tracers, it is more
394 * important to be fast than accurate.
396 tr->buffer_disabled = 0;
397 /* Make the flag seen by readers */
402 * tracing_on - enable tracing buffers
404 * This function enables tracing buffers that may have been
405 * disabled with tracing_off.
407 void tracing_on(void)
409 tracer_tracing_on(&global_trace);
411 EXPORT_SYMBOL_GPL(tracing_on);
414 * __trace_puts - write a constant string into the trace buffer.
415 * @ip: The address of the caller
416 * @str: The constant string to write
417 * @size: The size of the string.
419 int __trace_puts(unsigned long ip, const char *str, int size)
421 struct ring_buffer_event *event;
422 struct ring_buffer *buffer;
423 struct print_entry *entry;
424 unsigned long irq_flags;
428 pc = preempt_count();
430 if (unlikely(tracing_selftest_running || tracing_disabled))
433 alloc = sizeof(*entry) + size + 2; /* possible \n added */
435 local_save_flags(irq_flags);
436 buffer = global_trace.trace_buffer.buffer;
437 event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc,
442 entry = ring_buffer_event_data(event);
445 memcpy(&entry->buf, str, size);
447 /* Add a newline if necessary */
448 if (entry->buf[size - 1] != '\n') {
449 entry->buf[size] = '\n';
450 entry->buf[size + 1] = '\0';
452 entry->buf[size] = '\0';
454 __buffer_unlock_commit(buffer, event);
455 ftrace_trace_stack(buffer, irq_flags, 4, pc);
459 EXPORT_SYMBOL_GPL(__trace_puts);
462 * __trace_bputs - write the pointer to a constant string into trace buffer
463 * @ip: The address of the caller
464 * @str: The constant string to write to the buffer to
466 int __trace_bputs(unsigned long ip, const char *str)
468 struct ring_buffer_event *event;
469 struct ring_buffer *buffer;
470 struct bputs_entry *entry;
471 unsigned long irq_flags;
472 int size = sizeof(struct bputs_entry);
475 pc = preempt_count();
477 if (unlikely(tracing_selftest_running || tracing_disabled))
480 local_save_flags(irq_flags);
481 buffer = global_trace.trace_buffer.buffer;
482 event = trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size,
487 entry = ring_buffer_event_data(event);
491 __buffer_unlock_commit(buffer, event);
492 ftrace_trace_stack(buffer, irq_flags, 4, pc);
496 EXPORT_SYMBOL_GPL(__trace_bputs);
498 #ifdef CONFIG_TRACER_SNAPSHOT
500 * trace_snapshot - take a snapshot of the current buffer.
502 * This causes a swap between the snapshot buffer and the current live
503 * tracing buffer. You can use this to take snapshots of the live
504 * trace when some condition is triggered, but continue to trace.
506 * Note, make sure to allocate the snapshot with either
507 * a tracing_snapshot_alloc(), or by doing it manually
508 * with: echo 1 > /sys/kernel/debug/tracing/snapshot
510 * If the snapshot buffer is not allocated, it will stop tracing.
511 * Basically making a permanent snapshot.
513 void tracing_snapshot(void)
515 struct trace_array *tr = &global_trace;
516 struct tracer *tracer = tr->current_trace;
520 internal_trace_puts("*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n");
521 internal_trace_puts("*** snapshot is being ignored ***\n");
525 if (!tr->allocated_snapshot) {
526 internal_trace_puts("*** SNAPSHOT NOT ALLOCATED ***\n");
527 internal_trace_puts("*** stopping trace here! ***\n");
532 /* Note, snapshot can not be used when the tracer uses it */
533 if (tracer->use_max_tr) {
534 internal_trace_puts("*** LATENCY TRACER ACTIVE ***\n");
535 internal_trace_puts("*** Can not use snapshot (sorry) ***\n");
539 local_irq_save(flags);
540 update_max_tr(tr, current, smp_processor_id());
541 local_irq_restore(flags);
543 EXPORT_SYMBOL_GPL(tracing_snapshot);
545 static int resize_buffer_duplicate_size(struct trace_buffer *trace_buf,
546 struct trace_buffer *size_buf, int cpu_id);
547 static void set_buffer_entries(struct trace_buffer *buf, unsigned long val);
549 static int alloc_snapshot(struct trace_array *tr)
553 if (!tr->allocated_snapshot) {
555 /* allocate spare buffer */
556 ret = resize_buffer_duplicate_size(&tr->max_buffer,
557 &tr->trace_buffer, RING_BUFFER_ALL_CPUS);
561 tr->allocated_snapshot = true;
567 void free_snapshot(struct trace_array *tr)
570 * We don't free the ring buffer. instead, resize it because
571 * The max_tr ring buffer has some state (e.g. ring->clock) and
572 * we want preserve it.
574 ring_buffer_resize(tr->max_buffer.buffer, 1, RING_BUFFER_ALL_CPUS);
575 set_buffer_entries(&tr->max_buffer, 1);
576 tracing_reset_online_cpus(&tr->max_buffer);
577 tr->allocated_snapshot = false;
581 * trace_snapshot_alloc - allocate and take a snapshot of the current buffer.
583 * This is similar to trace_snapshot(), but it will allocate the
584 * snapshot buffer if it isn't already allocated. Use this only
585 * where it is safe to sleep, as the allocation may sleep.
587 * This causes a swap between the snapshot buffer and the current live
588 * tracing buffer. You can use this to take snapshots of the live
589 * trace when some condition is triggered, but continue to trace.
591 void tracing_snapshot_alloc(void)
593 struct trace_array *tr = &global_trace;
596 ret = alloc_snapshot(tr);
597 if (WARN_ON(ret < 0))
602 EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
604 void tracing_snapshot(void)
606 WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used");
608 EXPORT_SYMBOL_GPL(tracing_snapshot);
609 void tracing_snapshot_alloc(void)
614 EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
615 #endif /* CONFIG_TRACER_SNAPSHOT */
617 void tracer_tracing_off(struct trace_array *tr)
619 if (tr->trace_buffer.buffer)
620 ring_buffer_record_off(tr->trace_buffer.buffer);
622 * This flag is looked at when buffers haven't been allocated
623 * yet, or by some tracers (like irqsoff), that just want to
624 * know if the ring buffer has been disabled, but it can handle
625 * races of where it gets disabled but we still do a record.
626 * As the check is in the fast path of the tracers, it is more
627 * important to be fast than accurate.
629 tr->buffer_disabled = 1;
630 /* Make the flag seen by readers */
635 * tracing_off - turn off tracing buffers
637 * This function stops the tracing buffers from recording data.
638 * It does not disable any overhead the tracers themselves may
639 * be causing. This function simply causes all recording to
640 * the ring buffers to fail.
642 void tracing_off(void)
644 tracer_tracing_off(&global_trace);
646 EXPORT_SYMBOL_GPL(tracing_off);
649 * tracer_tracing_is_on - show real state of ring buffer enabled
650 * @tr : the trace array to know if ring buffer is enabled
652 * Shows real state of the ring buffer if it is enabled or not.
654 int tracer_tracing_is_on(struct trace_array *tr)
656 if (tr->trace_buffer.buffer)
657 return ring_buffer_record_is_on(tr->trace_buffer.buffer);
658 return !tr->buffer_disabled;
662 * tracing_is_on - show state of ring buffers enabled
664 int tracing_is_on(void)
666 return tracer_tracing_is_on(&global_trace);
668 EXPORT_SYMBOL_GPL(tracing_is_on);
670 static int __init set_buf_size(char *str)
672 unsigned long buf_size;
676 buf_size = memparse(str, &str);
677 /* nr_entries can not be zero */
680 trace_buf_size = buf_size;
683 __setup("trace_buf_size=", set_buf_size);
685 static int __init set_tracing_thresh(char *str)
687 unsigned long threshold;
692 ret = kstrtoul(str, 0, &threshold);
695 tracing_thresh = threshold * 1000;
698 __setup("tracing_thresh=", set_tracing_thresh);
700 unsigned long nsecs_to_usecs(unsigned long nsecs)
705 /* These must match the bit postions in trace_iterator_flags */
706 static const char *trace_options[] = {
740 int in_ns; /* is this clock in nanoseconds? */
742 { trace_clock_local, "local", 1 },
743 { trace_clock_global, "global", 1 },
744 { trace_clock_counter, "counter", 0 },
745 { trace_clock_jiffies, "uptime", 1 },
746 { trace_clock, "perf", 1 },
751 * trace_parser_get_init - gets the buffer for trace parser
753 int trace_parser_get_init(struct trace_parser *parser, int size)
755 memset(parser, 0, sizeof(*parser));
757 parser->buffer = kmalloc(size, GFP_KERNEL);
766 * trace_parser_put - frees the buffer for trace parser
768 void trace_parser_put(struct trace_parser *parser)
770 kfree(parser->buffer);
774 * trace_get_user - reads the user input string separated by space
775 * (matched by isspace(ch))
777 * For each string found the 'struct trace_parser' is updated,
778 * and the function returns.
780 * Returns number of bytes read.
782 * See kernel/trace/trace.h for 'struct trace_parser' details.
784 int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
785 size_t cnt, loff_t *ppos)
792 trace_parser_clear(parser);
794 ret = get_user(ch, ubuf++);
802 * The parser is not finished with the last write,
803 * continue reading the user input without skipping spaces.
806 /* skip white space */
807 while (cnt && isspace(ch)) {
808 ret = get_user(ch, ubuf++);
815 /* only spaces were written */
825 /* read the non-space input */
826 while (cnt && !isspace(ch)) {
827 if (parser->idx < parser->size - 1)
828 parser->buffer[parser->idx++] = ch;
833 ret = get_user(ch, ubuf++);
840 /* We either got finished input or we have to wait for another call. */
842 parser->buffer[parser->idx] = 0;
843 parser->cont = false;
844 } else if (parser->idx < parser->size - 1) {
846 parser->buffer[parser->idx++] = ch;
859 ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
867 if (s->len <= s->readpos)
870 len = s->len - s->readpos;
873 ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
883 static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
887 if (s->len <= s->readpos)
890 len = s->len - s->readpos;
893 memcpy(buf, s->buffer + s->readpos, cnt);
900 * ftrace_max_lock is used to protect the swapping of buffers
901 * when taking a max snapshot. The buffers themselves are
902 * protected by per_cpu spinlocks. But the action of the swap
903 * needs its own lock.
905 * This is defined as a arch_spinlock_t in order to help
906 * with performance when lockdep debugging is enabled.
908 * It is also used in other places outside the update_max_tr
909 * so it needs to be defined outside of the
910 * CONFIG_TRACER_MAX_TRACE.
912 static arch_spinlock_t ftrace_max_lock =
913 (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
915 unsigned long __read_mostly tracing_thresh;
917 #ifdef CONFIG_TRACER_MAX_TRACE
918 unsigned long __read_mostly tracing_max_latency;
921 * Copy the new maximum trace into the separate maximum-trace
922 * structure. (this way the maximum trace is permanently saved,
923 * for later retrieval via /sys/kernel/debug/tracing/latency_trace)
926 __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
928 struct trace_buffer *trace_buf = &tr->trace_buffer;
929 struct trace_buffer *max_buf = &tr->max_buffer;
930 struct trace_array_cpu *data = per_cpu_ptr(trace_buf->data, cpu);
931 struct trace_array_cpu *max_data = per_cpu_ptr(max_buf->data, cpu);
934 max_buf->time_start = data->preempt_timestamp;
936 max_data->saved_latency = tracing_max_latency;
937 max_data->critical_start = data->critical_start;
938 max_data->critical_end = data->critical_end;
940 memcpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
941 max_data->pid = tsk->pid;
943 * If tsk == current, then use current_uid(), as that does not use
944 * RCU. The irq tracer can be called out of RCU scope.
947 max_data->uid = current_uid();
949 max_data->uid = task_uid(tsk);
951 max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
952 max_data->policy = tsk->policy;
953 max_data->rt_priority = tsk->rt_priority;
955 /* record this tasks comm */
956 tracing_record_cmdline(tsk);
960 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
962 * @tsk: the task with the latency
963 * @cpu: The cpu that initiated the trace.
965 * Flip the buffers between the @tr and the max_tr and record information
966 * about which task was the cause of this latency.
969 update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
971 struct ring_buffer *buf;
976 WARN_ON_ONCE(!irqs_disabled());
978 if (!tr->allocated_snapshot) {
979 /* Only the nop tracer should hit this when disabling */
980 WARN_ON_ONCE(tr->current_trace != &nop_trace);
984 arch_spin_lock(&ftrace_max_lock);
986 buf = tr->trace_buffer.buffer;
987 tr->trace_buffer.buffer = tr->max_buffer.buffer;
988 tr->max_buffer.buffer = buf;
990 __update_max_tr(tr, tsk, cpu);
991 arch_spin_unlock(&ftrace_max_lock);
995 * update_max_tr_single - only copy one trace over, and reset the rest
997 * @tsk - task with the latency
998 * @cpu - the cpu of the buffer to copy.
1000 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
1003 update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
1010 WARN_ON_ONCE(!irqs_disabled());
1011 if (!tr->allocated_snapshot) {
1012 /* Only the nop tracer should hit this when disabling */
1013 WARN_ON_ONCE(tr->current_trace != &nop_trace);
1017 arch_spin_lock(&ftrace_max_lock);
1019 ret = ring_buffer_swap_cpu(tr->max_buffer.buffer, tr->trace_buffer.buffer, cpu);
1021 if (ret == -EBUSY) {
1023 * We failed to swap the buffer due to a commit taking
1024 * place on this CPU. We fail to record, but we reset
1025 * the max trace buffer (no one writes directly to it)
1026 * and flag that it failed.
1028 trace_array_printk_buf(tr->max_buffer.buffer, _THIS_IP_,
1029 "Failed to swap buffers due to commit in progress\n");
1032 WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);
1034 __update_max_tr(tr, tsk, cpu);
1035 arch_spin_unlock(&ftrace_max_lock);
1037 #endif /* CONFIG_TRACER_MAX_TRACE */
1039 static int default_wait_pipe(struct trace_iterator *iter)
1041 /* Iterators are static, they should be filled or empty */
1042 if (trace_buffer_iter(iter, iter->cpu_file))
1045 return ring_buffer_wait(iter->trace_buffer->buffer, iter->cpu_file);
1048 #ifdef CONFIG_FTRACE_STARTUP_TEST
1049 static int run_tracer_selftest(struct tracer *type)
1051 struct trace_array *tr = &global_trace;
1052 struct tracer *saved_tracer = tr->current_trace;
1055 if (!type->selftest || tracing_selftest_disabled)
1059 * Run a selftest on this tracer.
1060 * Here we reset the trace buffer, and set the current
1061 * tracer to be this tracer. The tracer can then run some
1062 * internal tracing to verify that everything is in order.
1063 * If we fail, we do not register this tracer.
1065 tracing_reset_online_cpus(&tr->trace_buffer);
1067 tr->current_trace = type;
1069 #ifdef CONFIG_TRACER_MAX_TRACE
1070 if (type->use_max_tr) {
1071 /* If we expanded the buffers, make sure the max is expanded too */
1072 if (ring_buffer_expanded)
1073 ring_buffer_resize(tr->max_buffer.buffer, trace_buf_size,
1074 RING_BUFFER_ALL_CPUS);
1075 tr->allocated_snapshot = true;
1079 /* the test is responsible for initializing and enabling */
1080 pr_info("Testing tracer %s: ", type->name);
1081 ret = type->selftest(type, tr);
1082 /* the test is responsible for resetting too */
1083 tr->current_trace = saved_tracer;
1085 printk(KERN_CONT "FAILED!\n");
1086 /* Add the warning after printing 'FAILED' */
1090 /* Only reset on passing, to avoid touching corrupted buffers */
1091 tracing_reset_online_cpus(&tr->trace_buffer);
1093 #ifdef CONFIG_TRACER_MAX_TRACE
1094 if (type->use_max_tr) {
1095 tr->allocated_snapshot = false;
1097 /* Shrink the max buffer again */
1098 if (ring_buffer_expanded)
1099 ring_buffer_resize(tr->max_buffer.buffer, 1,
1100 RING_BUFFER_ALL_CPUS);
1104 printk(KERN_CONT "PASSED\n");
1108 static inline int run_tracer_selftest(struct tracer *type)
1112 #endif /* CONFIG_FTRACE_STARTUP_TEST */
1115 * register_tracer - register a tracer with the ftrace system.
1116 * @type - the plugin for the tracer
1118 * Register a new plugin tracer.
1120 int register_tracer(struct tracer *type)
1126 pr_info("Tracer must have a name\n");
1130 if (strlen(type->name) >= MAX_TRACER_SIZE) {
1131 pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE);
1135 mutex_lock(&trace_types_lock);
1137 tracing_selftest_running = true;
1139 for (t = trace_types; t; t = t->next) {
1140 if (strcmp(type->name, t->name) == 0) {
1142 pr_info("Tracer %s already registered\n",
1149 if (!type->set_flag)
1150 type->set_flag = &dummy_set_flag;
1152 type->flags = &dummy_tracer_flags;
1154 if (!type->flags->opts)
1155 type->flags->opts = dummy_tracer_opt;
1156 if (!type->wait_pipe)
1157 type->wait_pipe = default_wait_pipe;
1159 ret = run_tracer_selftest(type);
1163 type->next = trace_types;
1167 tracing_selftest_running = false;
1168 mutex_unlock(&trace_types_lock);
1170 if (ret || !default_bootup_tracer)
1173 if (strncmp(default_bootup_tracer, type->name, MAX_TRACER_SIZE))
1176 printk(KERN_INFO "Starting tracer '%s'\n", type->name);
1177 /* Do we want this tracer to start on bootup? */
1178 tracing_set_tracer(type->name);
1179 default_bootup_tracer = NULL;
1180 /* disable other selftests, since this will break it. */
1181 tracing_selftest_disabled = true;
1182 #ifdef CONFIG_FTRACE_STARTUP_TEST
1183 printk(KERN_INFO "Disabling FTRACE selftests due to running tracer '%s'\n",
1191 void tracing_reset(struct trace_buffer *buf, int cpu)
1193 struct ring_buffer *buffer = buf->buffer;
1198 ring_buffer_record_disable(buffer);
1200 /* Make sure all commits have finished */
1201 synchronize_sched();
1202 ring_buffer_reset_cpu(buffer, cpu);
1204 ring_buffer_record_enable(buffer);
1207 void tracing_reset_online_cpus(struct trace_buffer *buf)
1209 struct ring_buffer *buffer = buf->buffer;
1215 ring_buffer_record_disable(buffer);
1217 /* Make sure all commits have finished */
1218 synchronize_sched();
1220 buf->time_start = buffer_ftrace_now(buf, buf->cpu);
1222 for_each_online_cpu(cpu)
1223 ring_buffer_reset_cpu(buffer, cpu);
1225 ring_buffer_record_enable(buffer);
1228 /* Must have trace_types_lock held */
1229 void tracing_reset_all_online_cpus(void)
1231 struct trace_array *tr;
1233 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
1234 tracing_reset_online_cpus(&tr->trace_buffer);
1235 #ifdef CONFIG_TRACER_MAX_TRACE
1236 tracing_reset_online_cpus(&tr->max_buffer);
1241 #define SAVED_CMDLINES 128
1242 #define NO_CMDLINE_MAP UINT_MAX
1243 static unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
1244 static unsigned map_cmdline_to_pid[SAVED_CMDLINES];
1245 static char saved_cmdlines[SAVED_CMDLINES][TASK_COMM_LEN];
1246 static unsigned saved_tgids[SAVED_CMDLINES];
1247 static int cmdline_idx;
1248 static arch_spinlock_t trace_cmdline_lock = __ARCH_SPIN_LOCK_UNLOCKED;
1250 /* temporary disable recording */
1251 static atomic_t trace_record_cmdline_disabled __read_mostly;
1253 static void trace_init_cmdlines(void)
1255 memset(&map_pid_to_cmdline, NO_CMDLINE_MAP, sizeof(map_pid_to_cmdline));
1256 memset(&map_cmdline_to_pid, NO_CMDLINE_MAP, sizeof(map_cmdline_to_pid));
1260 int is_tracing_stopped(void)
1262 return global_trace.stop_count;
1266 * ftrace_off_permanent - disable all ftrace code permanently
1268 * This should only be called when a serious anomally has
1269 * been detected. This will turn off the function tracing,
1270 * ring buffers, and other tracing utilites. It takes no
1271 * locks and can be called from any context.
1273 void ftrace_off_permanent(void)
1275 tracing_disabled = 1;
1277 tracing_off_permanent();
1281 * tracing_start - quick start of the tracer
1283 * If tracing is enabled but was stopped by tracing_stop,
1284 * this will start the tracer back up.
1286 void tracing_start(void)
1288 struct ring_buffer *buffer;
1289 unsigned long flags;
1291 if (tracing_disabled)
1294 raw_spin_lock_irqsave(&global_trace.start_lock, flags);
1295 if (--global_trace.stop_count) {
1296 if (global_trace.stop_count < 0) {
1297 /* Someone screwed up their debugging */
1299 global_trace.stop_count = 0;
1304 /* Prevent the buffers from switching */
1305 arch_spin_lock(&ftrace_max_lock);
1307 buffer = global_trace.trace_buffer.buffer;
1309 ring_buffer_record_enable(buffer);
1311 #ifdef CONFIG_TRACER_MAX_TRACE
1312 buffer = global_trace.max_buffer.buffer;
1314 ring_buffer_record_enable(buffer);
1317 arch_spin_unlock(&ftrace_max_lock);
1320 raw_spin_unlock_irqrestore(&global_trace.start_lock, flags);
1323 static void tracing_start_tr(struct trace_array *tr)
1325 struct ring_buffer *buffer;
1326 unsigned long flags;
1328 if (tracing_disabled)
1331 /* If global, we need to also start the max tracer */
1332 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
1333 return tracing_start();
1335 raw_spin_lock_irqsave(&tr->start_lock, flags);
1337 if (--tr->stop_count) {
1338 if (tr->stop_count < 0) {
1339 /* Someone screwed up their debugging */
1346 buffer = tr->trace_buffer.buffer;
1348 ring_buffer_record_enable(buffer);
1351 raw_spin_unlock_irqrestore(&tr->start_lock, flags);
1355 * tracing_stop - quick stop of the tracer
1357 * Light weight way to stop tracing. Use in conjunction with
1360 void tracing_stop(void)
1362 struct ring_buffer *buffer;
1363 unsigned long flags;
1365 raw_spin_lock_irqsave(&global_trace.start_lock, flags);
1366 if (global_trace.stop_count++)
1369 /* Prevent the buffers from switching */
1370 arch_spin_lock(&ftrace_max_lock);
1372 buffer = global_trace.trace_buffer.buffer;
1374 ring_buffer_record_disable(buffer);
1376 #ifdef CONFIG_TRACER_MAX_TRACE
1377 buffer = global_trace.max_buffer.buffer;
1379 ring_buffer_record_disable(buffer);
1382 arch_spin_unlock(&ftrace_max_lock);
1385 raw_spin_unlock_irqrestore(&global_trace.start_lock, flags);
1388 static void tracing_stop_tr(struct trace_array *tr)
1390 struct ring_buffer *buffer;
1391 unsigned long flags;
1393 /* If global, we need to also stop the max tracer */
1394 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
1395 return tracing_stop();
1397 raw_spin_lock_irqsave(&tr->start_lock, flags);
1398 if (tr->stop_count++)
1401 buffer = tr->trace_buffer.buffer;
1403 ring_buffer_record_disable(buffer);
1406 raw_spin_unlock_irqrestore(&tr->start_lock, flags);
1409 void trace_stop_cmdline_recording(void);
1411 static int trace_save_cmdline(struct task_struct *tsk)
1415 if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT))
1419 * It's not the end of the world if we don't get
1420 * the lock, but we also don't want to spin
1421 * nor do we want to disable interrupts,
1422 * so if we miss here, then better luck next time.
1424 if (!arch_spin_trylock(&trace_cmdline_lock))
1427 idx = map_pid_to_cmdline[tsk->pid];
1428 if (idx == NO_CMDLINE_MAP) {
1429 idx = (cmdline_idx + 1) % SAVED_CMDLINES;
1432 * Check whether the cmdline buffer at idx has a pid
1433 * mapped. We are going to overwrite that entry so we
1434 * need to clear the map_pid_to_cmdline. Otherwise we
1435 * would read the new comm for the old pid.
1437 pid = map_cmdline_to_pid[idx];
1438 if (pid != NO_CMDLINE_MAP)
1439 map_pid_to_cmdline[pid] = NO_CMDLINE_MAP;
1441 map_cmdline_to_pid[idx] = tsk->pid;
1442 map_pid_to_cmdline[tsk->pid] = idx;
1447 memcpy(&saved_cmdlines[idx], tsk->comm, TASK_COMM_LEN);
1448 saved_tgids[idx] = tsk->tgid;
1450 arch_spin_unlock(&trace_cmdline_lock);
1455 void trace_find_cmdline(int pid, char comm[])
1460 strcpy(comm, "<idle>");
1464 if (WARN_ON_ONCE(pid < 0)) {
1465 strcpy(comm, "<XXX>");
1469 if (pid > PID_MAX_DEFAULT) {
1470 strcpy(comm, "<...>");
1475 arch_spin_lock(&trace_cmdline_lock);
1476 map = map_pid_to_cmdline[pid];
1477 if (map != NO_CMDLINE_MAP)
1478 strcpy(comm, saved_cmdlines[map]);
1480 strcpy(comm, "<...>");
1482 arch_spin_unlock(&trace_cmdline_lock);
1486 int trace_find_tgid(int pid)
1492 arch_spin_lock(&trace_cmdline_lock);
1493 map = map_pid_to_cmdline[pid];
1494 if (map != NO_CMDLINE_MAP)
1495 tgid = saved_tgids[map];
1499 arch_spin_unlock(&trace_cmdline_lock);
1505 void tracing_record_cmdline(struct task_struct *tsk)
1507 if (atomic_read(&trace_record_cmdline_disabled) || !tracing_is_on())
1510 if (!__this_cpu_read(trace_cmdline_save))
1513 if (trace_save_cmdline(tsk))
1514 __this_cpu_write(trace_cmdline_save, false);
1518 tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
1521 struct task_struct *tsk = current;
1523 entry->preempt_count = pc & 0xff;
1524 entry->pid = (tsk) ? tsk->pid : 0;
1526 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
1527 (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
1529 TRACE_FLAG_IRQS_NOSUPPORT |
1531 ((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
1532 ((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
1533 (need_resched() ? TRACE_FLAG_NEED_RESCHED : 0);
1535 EXPORT_SYMBOL_GPL(tracing_generic_entry_update);
1537 struct ring_buffer_event *
1538 trace_buffer_lock_reserve(struct ring_buffer *buffer,
1541 unsigned long flags, int pc)
1543 struct ring_buffer_event *event;
1545 event = ring_buffer_lock_reserve(buffer, len);
1546 if (event != NULL) {
1547 struct trace_entry *ent = ring_buffer_event_data(event);
1549 tracing_generic_entry_update(ent, flags, pc);
1557 __buffer_unlock_commit(struct ring_buffer *buffer, struct ring_buffer_event *event)
1559 __this_cpu_write(trace_cmdline_save, true);
1560 ring_buffer_unlock_commit(buffer, event);
1564 __trace_buffer_unlock_commit(struct ring_buffer *buffer,
1565 struct ring_buffer_event *event,
1566 unsigned long flags, int pc)
1568 __buffer_unlock_commit(buffer, event);
1570 ftrace_trace_stack(buffer, flags, 6, pc);
1571 ftrace_trace_userstack(buffer, flags, pc);
1574 void trace_buffer_unlock_commit(struct ring_buffer *buffer,
1575 struct ring_buffer_event *event,
1576 unsigned long flags, int pc)
1578 __trace_buffer_unlock_commit(buffer, event, flags, pc);
1580 EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit);
1582 struct ring_buffer_event *
1583 trace_event_buffer_lock_reserve(struct ring_buffer **current_rb,
1584 struct ftrace_event_file *ftrace_file,
1585 int type, unsigned long len,
1586 unsigned long flags, int pc)
1588 *current_rb = ftrace_file->tr->trace_buffer.buffer;
1589 return trace_buffer_lock_reserve(*current_rb,
1590 type, len, flags, pc);
1592 EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve);
1594 struct ring_buffer_event *
1595 trace_current_buffer_lock_reserve(struct ring_buffer **current_rb,
1596 int type, unsigned long len,
1597 unsigned long flags, int pc)
1599 *current_rb = global_trace.trace_buffer.buffer;
1600 return trace_buffer_lock_reserve(*current_rb,
1601 type, len, flags, pc);
1603 EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve);
1605 void trace_current_buffer_unlock_commit(struct ring_buffer *buffer,
1606 struct ring_buffer_event *event,
1607 unsigned long flags, int pc)
1609 __trace_buffer_unlock_commit(buffer, event, flags, pc);
1611 EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit);
1613 void trace_buffer_unlock_commit_regs(struct ring_buffer *buffer,
1614 struct ring_buffer_event *event,
1615 unsigned long flags, int pc,
1616 struct pt_regs *regs)
1618 __buffer_unlock_commit(buffer, event);
1620 ftrace_trace_stack_regs(buffer, flags, 0, pc, regs);
1621 ftrace_trace_userstack(buffer, flags, pc);
1623 EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit_regs);
1625 void trace_current_buffer_discard_commit(struct ring_buffer *buffer,
1626 struct ring_buffer_event *event)
1628 ring_buffer_discard_commit(buffer, event);
1630 EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit);
1633 trace_function(struct trace_array *tr,
1634 unsigned long ip, unsigned long parent_ip, unsigned long flags,
1637 struct ftrace_event_call *call = &event_function;
1638 struct ring_buffer *buffer = tr->trace_buffer.buffer;
1639 struct ring_buffer_event *event;
1640 struct ftrace_entry *entry;
1642 /* If we are reading the ring buffer, don't trace */
1643 if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))
1646 event = trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
1650 entry = ring_buffer_event_data(event);
1652 entry->parent_ip = parent_ip;
1654 if (!filter_check_discard(call, entry, buffer, event))
1655 __buffer_unlock_commit(buffer, event);
1659 ftrace(struct trace_array *tr, struct trace_array_cpu *data,
1660 unsigned long ip, unsigned long parent_ip, unsigned long flags,
1663 if (likely(!atomic_read(&data->disabled)))
1664 trace_function(tr, ip, parent_ip, flags, pc);
1667 #ifdef CONFIG_STACKTRACE
1669 #define FTRACE_STACK_MAX_ENTRIES (PAGE_SIZE / sizeof(unsigned long))
1670 struct ftrace_stack {
1671 unsigned long calls[FTRACE_STACK_MAX_ENTRIES];
1674 static DEFINE_PER_CPU(struct ftrace_stack, ftrace_stack);
1675 static DEFINE_PER_CPU(int, ftrace_stack_reserve);
1677 static void __ftrace_trace_stack(struct ring_buffer *buffer,
1678 unsigned long flags,
1679 int skip, int pc, struct pt_regs *regs)
1681 struct ftrace_event_call *call = &event_kernel_stack;
1682 struct ring_buffer_event *event;
1683 struct stack_entry *entry;
1684 struct stack_trace trace;
1686 int size = FTRACE_STACK_ENTRIES;
1688 trace.nr_entries = 0;
1692 * Since events can happen in NMIs there's no safe way to
1693 * use the per cpu ftrace_stacks. We reserve it and if an interrupt
1694 * or NMI comes in, it will just have to use the default
1695 * FTRACE_STACK_SIZE.
1697 preempt_disable_notrace();
1699 use_stack = __this_cpu_inc_return(ftrace_stack_reserve);
1701 * We don't need any atomic variables, just a barrier.
1702 * If an interrupt comes in, we don't care, because it would
1703 * have exited and put the counter back to what we want.
1704 * We just need a barrier to keep gcc from moving things
1708 if (use_stack == 1) {
1709 trace.entries = &__get_cpu_var(ftrace_stack).calls[0];
1710 trace.max_entries = FTRACE_STACK_MAX_ENTRIES;
1713 save_stack_trace_regs(regs, &trace);
1715 save_stack_trace(&trace);
1717 if (trace.nr_entries > size)
1718 size = trace.nr_entries;
1720 /* From now on, use_stack is a boolean */
1723 size *= sizeof(unsigned long);
1725 event = trace_buffer_lock_reserve(buffer, TRACE_STACK,
1726 sizeof(*entry) + size, flags, pc);
1729 entry = ring_buffer_event_data(event);
1731 memset(&entry->caller, 0, size);
1734 memcpy(&entry->caller, trace.entries,
1735 trace.nr_entries * sizeof(unsigned long));
1737 trace.max_entries = FTRACE_STACK_ENTRIES;
1738 trace.entries = entry->caller;
1740 save_stack_trace_regs(regs, &trace);
1742 save_stack_trace(&trace);
1745 entry->size = trace.nr_entries;
1747 if (!filter_check_discard(call, entry, buffer, event))
1748 __buffer_unlock_commit(buffer, event);
1751 /* Again, don't let gcc optimize things here */
1753 __this_cpu_dec(ftrace_stack_reserve);
1754 preempt_enable_notrace();
1758 void ftrace_trace_stack_regs(struct ring_buffer *buffer, unsigned long flags,
1759 int skip, int pc, struct pt_regs *regs)
1761 if (!(trace_flags & TRACE_ITER_STACKTRACE))
1764 __ftrace_trace_stack(buffer, flags, skip, pc, regs);
1767 void ftrace_trace_stack(struct ring_buffer *buffer, unsigned long flags,
1770 if (!(trace_flags & TRACE_ITER_STACKTRACE))
1773 __ftrace_trace_stack(buffer, flags, skip, pc, NULL);
1776 void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
1779 __ftrace_trace_stack(tr->trace_buffer.buffer, flags, skip, pc, NULL);
1783 * trace_dump_stack - record a stack back trace in the trace buffer
1784 * @skip: Number of functions to skip (helper handlers)
1786 void trace_dump_stack(int skip)
1788 unsigned long flags;
1790 if (tracing_disabled || tracing_selftest_running)
1793 local_save_flags(flags);
1796 * Skip 3 more, seems to get us at the caller of
1800 __ftrace_trace_stack(global_trace.trace_buffer.buffer,
1801 flags, skip, preempt_count(), NULL);
1804 static DEFINE_PER_CPU(int, user_stack_count);
1807 ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
1809 struct ftrace_event_call *call = &event_user_stack;
1810 struct ring_buffer_event *event;
1811 struct userstack_entry *entry;
1812 struct stack_trace trace;
1814 if (!(trace_flags & TRACE_ITER_USERSTACKTRACE))
1818 * NMIs can not handle page faults, even with fix ups.
1819 * The save user stack can (and often does) fault.
1821 if (unlikely(in_nmi()))
1825 * prevent recursion, since the user stack tracing may
1826 * trigger other kernel events.
1829 if (__this_cpu_read(user_stack_count))
1832 __this_cpu_inc(user_stack_count);
1834 event = trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
1835 sizeof(*entry), flags, pc);
1837 goto out_drop_count;
1838 entry = ring_buffer_event_data(event);
1840 entry->tgid = current->tgid;
1841 memset(&entry->caller, 0, sizeof(entry->caller));
1843 trace.nr_entries = 0;
1844 trace.max_entries = FTRACE_STACK_ENTRIES;
1846 trace.entries = entry->caller;
1848 save_stack_trace_user(&trace);
1849 if (!filter_check_discard(call, entry, buffer, event))
1850 __buffer_unlock_commit(buffer, event);
1853 __this_cpu_dec(user_stack_count);
1859 static void __trace_userstack(struct trace_array *tr, unsigned long flags)
1861 ftrace_trace_userstack(tr, flags, preempt_count());
1865 #endif /* CONFIG_STACKTRACE */
1867 /* created for use with alloc_percpu */
1868 struct trace_buffer_struct {
1869 char buffer[TRACE_BUF_SIZE];
1872 static struct trace_buffer_struct *trace_percpu_buffer;
1873 static struct trace_buffer_struct *trace_percpu_sirq_buffer;
1874 static struct trace_buffer_struct *trace_percpu_irq_buffer;
1875 static struct trace_buffer_struct *trace_percpu_nmi_buffer;
1878 * The buffer used is dependent on the context. There is a per cpu
1879 * buffer for normal context, softirq contex, hard irq context and
1880 * for NMI context. Thise allows for lockless recording.
1882 * Note, if the buffers failed to be allocated, then this returns NULL
1884 static char *get_trace_buf(void)
1886 struct trace_buffer_struct *percpu_buffer;
1889 * If we have allocated per cpu buffers, then we do not
1890 * need to do any locking.
1893 percpu_buffer = trace_percpu_nmi_buffer;
1895 percpu_buffer = trace_percpu_irq_buffer;
1896 else if (in_softirq())
1897 percpu_buffer = trace_percpu_sirq_buffer;
1899 percpu_buffer = trace_percpu_buffer;
1904 return this_cpu_ptr(&percpu_buffer->buffer[0]);
1907 static int alloc_percpu_trace_buffer(void)
1909 struct trace_buffer_struct *buffers;
1910 struct trace_buffer_struct *sirq_buffers;
1911 struct trace_buffer_struct *irq_buffers;
1912 struct trace_buffer_struct *nmi_buffers;
1914 buffers = alloc_percpu(struct trace_buffer_struct);
1918 sirq_buffers = alloc_percpu(struct trace_buffer_struct);
1922 irq_buffers = alloc_percpu(struct trace_buffer_struct);
1926 nmi_buffers = alloc_percpu(struct trace_buffer_struct);
1930 trace_percpu_buffer = buffers;
1931 trace_percpu_sirq_buffer = sirq_buffers;
1932 trace_percpu_irq_buffer = irq_buffers;
1933 trace_percpu_nmi_buffer = nmi_buffers;
1938 free_percpu(irq_buffers);
1940 free_percpu(sirq_buffers);
1942 free_percpu(buffers);
1944 WARN(1, "Could not allocate percpu trace_printk buffer");
1948 static int buffers_allocated;
1950 void trace_printk_init_buffers(void)
1952 if (buffers_allocated)
1955 if (alloc_percpu_trace_buffer())
1958 pr_info("ftrace: Allocated trace_printk buffers\n");
1960 /* Expand the buffers to set size */
1961 tracing_update_buffers();
1963 buffers_allocated = 1;
1966 * trace_printk_init_buffers() can be called by modules.
1967 * If that happens, then we need to start cmdline recording
1968 * directly here. If the global_trace.buffer is already
1969 * allocated here, then this was called by module code.
1971 if (global_trace.trace_buffer.buffer)
1972 tracing_start_cmdline_record();
1975 void trace_printk_start_comm(void)
1977 /* Start tracing comms if trace printk is set */
1978 if (!buffers_allocated)
1980 tracing_start_cmdline_record();
1983 static void trace_printk_start_stop_comm(int enabled)
1985 if (!buffers_allocated)
1989 tracing_start_cmdline_record();
1991 tracing_stop_cmdline_record();
1995 * trace_vbprintk - write binary msg to tracing buffer
1998 int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
2000 struct ftrace_event_call *call = &event_bprint;
2001 struct ring_buffer_event *event;
2002 struct ring_buffer *buffer;
2003 struct trace_array *tr = &global_trace;
2004 struct bprint_entry *entry;
2005 unsigned long flags;
2007 int len = 0, size, pc;
2009 if (unlikely(tracing_selftest_running || tracing_disabled))
2012 /* Don't pollute graph traces with trace_vprintk internals */
2013 pause_graph_tracing();
2015 pc = preempt_count();
2016 preempt_disable_notrace();
2018 tbuffer = get_trace_buf();
2024 len = vbin_printf((u32 *)tbuffer, TRACE_BUF_SIZE/sizeof(int), fmt, args);
2026 if (len > TRACE_BUF_SIZE/sizeof(int) || len < 0)
2029 local_save_flags(flags);
2030 size = sizeof(*entry) + sizeof(u32) * len;
2031 buffer = tr->trace_buffer.buffer;
2032 event = trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
2036 entry = ring_buffer_event_data(event);
2040 memcpy(entry->buf, tbuffer, sizeof(u32) * len);
2041 if (!filter_check_discard(call, entry, buffer, event)) {
2042 __buffer_unlock_commit(buffer, event);
2043 ftrace_trace_stack(buffer, flags, 6, pc);
2047 preempt_enable_notrace();
2048 unpause_graph_tracing();
2052 EXPORT_SYMBOL_GPL(trace_vbprintk);
2055 __trace_array_vprintk(struct ring_buffer *buffer,
2056 unsigned long ip, const char *fmt, va_list args)
2058 struct ftrace_event_call *call = &event_print;
2059 struct ring_buffer_event *event;
2060 int len = 0, size, pc;
2061 struct print_entry *entry;
2062 unsigned long flags;
2065 if (tracing_disabled || tracing_selftest_running)
2068 /* Don't pollute graph traces with trace_vprintk internals */
2069 pause_graph_tracing();
2071 pc = preempt_count();
2072 preempt_disable_notrace();
2075 tbuffer = get_trace_buf();
2081 len = vsnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args);
2082 if (len > TRACE_BUF_SIZE)
2085 local_save_flags(flags);
2086 size = sizeof(*entry) + len + 1;
2087 event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
2091 entry = ring_buffer_event_data(event);
2094 memcpy(&entry->buf, tbuffer, len);
2095 entry->buf[len] = '\0';
2096 if (!filter_check_discard(call, entry, buffer, event)) {
2097 __buffer_unlock_commit(buffer, event);
2098 ftrace_trace_stack(buffer, flags, 6, pc);
2101 preempt_enable_notrace();
2102 unpause_graph_tracing();
2107 int trace_array_vprintk(struct trace_array *tr,
2108 unsigned long ip, const char *fmt, va_list args)
2110 return __trace_array_vprintk(tr->trace_buffer.buffer, ip, fmt, args);
2113 int trace_array_printk(struct trace_array *tr,
2114 unsigned long ip, const char *fmt, ...)
2119 if (!(trace_flags & TRACE_ITER_PRINTK))
2123 ret = trace_array_vprintk(tr, ip, fmt, ap);
2128 int trace_array_printk_buf(struct ring_buffer *buffer,
2129 unsigned long ip, const char *fmt, ...)
2134 if (!(trace_flags & TRACE_ITER_PRINTK))
2138 ret = __trace_array_vprintk(buffer, ip, fmt, ap);
2143 int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
2145 return trace_array_vprintk(&global_trace, ip, fmt, args);
2147 EXPORT_SYMBOL_GPL(trace_vprintk);
2149 static void trace_iterator_increment(struct trace_iterator *iter)
2151 struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, iter->cpu);
2155 ring_buffer_read(buf_iter, NULL);
2158 static struct trace_entry *
2159 peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts,
2160 unsigned long *lost_events)
2162 struct ring_buffer_event *event;
2163 struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, cpu);
2166 event = ring_buffer_iter_peek(buf_iter, ts);
2168 event = ring_buffer_peek(iter->trace_buffer->buffer, cpu, ts,
2172 iter->ent_size = ring_buffer_event_length(event);
2173 return ring_buffer_event_data(event);
2179 static struct trace_entry *
2180 __find_next_entry(struct trace_iterator *iter, int *ent_cpu,
2181 unsigned long *missing_events, u64 *ent_ts)
2183 struct ring_buffer *buffer = iter->trace_buffer->buffer;
2184 struct trace_entry *ent, *next = NULL;
2185 unsigned long lost_events = 0, next_lost = 0;
2186 int cpu_file = iter->cpu_file;
2187 u64 next_ts = 0, ts;
2193 * If we are in a per_cpu trace file, don't bother by iterating over
2194 * all cpu and peek directly.
2196 if (cpu_file > RING_BUFFER_ALL_CPUS) {
2197 if (ring_buffer_empty_cpu(buffer, cpu_file))
2199 ent = peek_next_entry(iter, cpu_file, ent_ts, missing_events);
2201 *ent_cpu = cpu_file;
2206 for_each_tracing_cpu(cpu) {
2208 if (ring_buffer_empty_cpu(buffer, cpu))
2211 ent = peek_next_entry(iter, cpu, &ts, &lost_events);
2214 * Pick the entry with the smallest timestamp:
2216 if (ent && (!next || ts < next_ts)) {
2220 next_lost = lost_events;
2221 next_size = iter->ent_size;
2225 iter->ent_size = next_size;
2228 *ent_cpu = next_cpu;
2234 *missing_events = next_lost;
2239 /* Find the next real entry, without updating the iterator itself */
2240 struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
2241 int *ent_cpu, u64 *ent_ts)
2243 return __find_next_entry(iter, ent_cpu, NULL, ent_ts);
2246 /* Find the next real entry, and increment the iterator to the next entry */
2247 void *trace_find_next_entry_inc(struct trace_iterator *iter)
2249 iter->ent = __find_next_entry(iter, &iter->cpu,
2250 &iter->lost_events, &iter->ts);
2253 trace_iterator_increment(iter);
2255 return iter->ent ? iter : NULL;
2258 static void trace_consume(struct trace_iterator *iter)
2260 ring_buffer_consume(iter->trace_buffer->buffer, iter->cpu, &iter->ts,
2261 &iter->lost_events);
2264 static void *s_next(struct seq_file *m, void *v, loff_t *pos)
2266 struct trace_iterator *iter = m->private;
2270 WARN_ON_ONCE(iter->leftover);
2274 /* can't go backwards */
2279 ent = trace_find_next_entry_inc(iter);
2283 while (ent && iter->idx < i)
2284 ent = trace_find_next_entry_inc(iter);
2291 void tracing_iter_reset(struct trace_iterator *iter, int cpu)
2293 struct ring_buffer_event *event;
2294 struct ring_buffer_iter *buf_iter;
2295 unsigned long entries = 0;
2298 per_cpu_ptr(iter->trace_buffer->data, cpu)->skipped_entries = 0;
2300 buf_iter = trace_buffer_iter(iter, cpu);
2304 ring_buffer_iter_reset(buf_iter);
2307 * We could have the case with the max latency tracers
2308 * that a reset never took place on a cpu. This is evident
2309 * by the timestamp being before the start of the buffer.
2311 while ((event = ring_buffer_iter_peek(buf_iter, &ts))) {
2312 if (ts >= iter->trace_buffer->time_start)
2315 ring_buffer_read(buf_iter, NULL);
2318 per_cpu_ptr(iter->trace_buffer->data, cpu)->skipped_entries = entries;
2322 * The current tracer is copied to avoid a global locking
2325 static void *s_start(struct seq_file *m, loff_t *pos)
2327 struct trace_iterator *iter = m->private;
2328 struct trace_array *tr = iter->tr;
2329 int cpu_file = iter->cpu_file;
2335 * copy the tracer to avoid using a global lock all around.
2336 * iter->trace is a copy of current_trace, the pointer to the
2337 * name may be used instead of a strcmp(), as iter->trace->name
2338 * will point to the same string as current_trace->name.
2340 mutex_lock(&trace_types_lock);
2341 if (unlikely(tr->current_trace && iter->trace->name != tr->current_trace->name))
2342 *iter->trace = *tr->current_trace;
2343 mutex_unlock(&trace_types_lock);
2345 #ifdef CONFIG_TRACER_MAX_TRACE
2346 if (iter->snapshot && iter->trace->use_max_tr)
2347 return ERR_PTR(-EBUSY);
2350 if (!iter->snapshot)
2351 atomic_inc(&trace_record_cmdline_disabled);
2353 if (*pos != iter->pos) {
2358 if (cpu_file == RING_BUFFER_ALL_CPUS) {
2359 for_each_tracing_cpu(cpu)
2360 tracing_iter_reset(iter, cpu);
2362 tracing_iter_reset(iter, cpu_file);
2365 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
2370 * If we overflowed the seq_file before, then we want
2371 * to just reuse the trace_seq buffer again.
2377 p = s_next(m, p, &l);
2381 trace_event_read_lock();
2382 trace_access_lock(cpu_file);
2386 static void s_stop(struct seq_file *m, void *p)
2388 struct trace_iterator *iter = m->private;
2390 #ifdef CONFIG_TRACER_MAX_TRACE
2391 if (iter->snapshot && iter->trace->use_max_tr)
2395 if (!iter->snapshot)
2396 atomic_dec(&trace_record_cmdline_disabled);
2398 trace_access_unlock(iter->cpu_file);
2399 trace_event_read_unlock();
2403 get_total_entries(struct trace_buffer *buf,
2404 unsigned long *total, unsigned long *entries)
2406 unsigned long count;
2412 for_each_tracing_cpu(cpu) {
2413 count = ring_buffer_entries_cpu(buf->buffer, cpu);
2415 * If this buffer has skipped entries, then we hold all
2416 * entries for the trace and we need to ignore the
2417 * ones before the time stamp.
2419 if (per_cpu_ptr(buf->data, cpu)->skipped_entries) {
2420 count -= per_cpu_ptr(buf->data, cpu)->skipped_entries;
2421 /* total is the same as the entries */
2425 ring_buffer_overrun_cpu(buf->buffer, cpu);
2430 static void print_lat_help_header(struct seq_file *m)
2432 seq_puts(m, "# _------=> CPU# \n");
2433 seq_puts(m, "# / _-----=> irqs-off \n");
2434 seq_puts(m, "# | / _----=> need-resched \n");
2435 seq_puts(m, "# || / _---=> hardirq/softirq \n");
2436 seq_puts(m, "# ||| / _--=> preempt-depth \n");
2437 seq_puts(m, "# |||| / delay \n");
2438 seq_puts(m, "# cmd pid ||||| time | caller \n");
2439 seq_puts(m, "# \\ / ||||| \\ | / \n");
2442 static void print_event_info(struct trace_buffer *buf, struct seq_file *m)
2444 unsigned long total;
2445 unsigned long entries;
2447 get_total_entries(buf, &total, &entries);
2448 seq_printf(m, "# entries-in-buffer/entries-written: %lu/%lu #P:%d\n",
2449 entries, total, num_online_cpus());
2453 static void print_func_help_header(struct trace_buffer *buf, struct seq_file *m)
2455 print_event_info(buf, m);
2456 seq_puts(m, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
2457 seq_puts(m, "# | | | | |\n");
2460 static void print_func_help_header_tgid(struct trace_buffer *buf, struct seq_file *m)
2462 print_event_info(buf, m);
2463 seq_puts(m, "# TASK-PID TGID CPU# TIMESTAMP FUNCTION\n");
2464 seq_puts(m, "# | | | | | |\n");
2467 static void print_func_help_header_irq(struct trace_buffer *buf, struct seq_file *m)
2469 print_event_info(buf, m);
2470 seq_puts(m, "# _-----=> irqs-off\n");
2471 seq_puts(m, "# / _----=> need-resched\n");
2472 seq_puts(m, "# | / _---=> hardirq/softirq\n");
2473 seq_puts(m, "# || / _--=> preempt-depth\n");
2474 seq_puts(m, "# ||| / delay\n");
2475 seq_puts(m, "# TASK-PID CPU# |||| TIMESTAMP FUNCTION\n");
2476 seq_puts(m, "# | | | |||| | |\n");
2479 static void print_func_help_header_irq_tgid(struct trace_buffer *buf, struct seq_file *m)
2481 print_event_info(buf, m);
2482 seq_puts(m, "# _-----=> irqs-off\n");
2483 seq_puts(m, "# / _----=> need-resched\n");
2484 seq_puts(m, "# | / _---=> hardirq/softirq\n");
2485 seq_puts(m, "# || / _--=> preempt-depth\n");
2486 seq_puts(m, "# ||| / delay\n");
2487 seq_puts(m, "# TASK-PID TGID CPU# |||| TIMESTAMP FUNCTION\n");
2488 seq_puts(m, "# | | | | |||| | |\n");
2492 print_trace_header(struct seq_file *m, struct trace_iterator *iter)
2494 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
2495 struct trace_buffer *buf = iter->trace_buffer;
2496 struct trace_array_cpu *data = per_cpu_ptr(buf->data, buf->cpu);
2497 struct tracer *type = iter->trace;
2498 unsigned long entries;
2499 unsigned long total;
2500 const char *name = "preemption";
2504 get_total_entries(buf, &total, &entries);
2506 seq_printf(m, "# %s latency trace v1.1.5 on %s\n",
2508 seq_puts(m, "# -----------------------------------"
2509 "---------------------------------\n");
2510 seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d |"
2511 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
2512 nsecs_to_usecs(data->saved_latency),
2516 #if defined(CONFIG_PREEMPT_NONE)
2518 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
2520 #elif defined(CONFIG_PREEMPT)
2525 /* These are reserved for later use */
2528 seq_printf(m, " #P:%d)\n", num_online_cpus());
2532 seq_puts(m, "# -----------------\n");
2533 seq_printf(m, "# | task: %.16s-%d "
2534 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
2535 data->comm, data->pid,
2536 from_kuid_munged(seq_user_ns(m), data->uid), data->nice,
2537 data->policy, data->rt_priority);
2538 seq_puts(m, "# -----------------\n");
2540 if (data->critical_start) {
2541 seq_puts(m, "# => started at: ");
2542 seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
2543 trace_print_seq(m, &iter->seq);
2544 seq_puts(m, "\n# => ended at: ");
2545 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
2546 trace_print_seq(m, &iter->seq);
2547 seq_puts(m, "\n#\n");
2553 static void test_cpu_buff_start(struct trace_iterator *iter)
2555 struct trace_seq *s = &iter->seq;
2557 if (!(trace_flags & TRACE_ITER_ANNOTATE))
2560 if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
2563 if (cpumask_test_cpu(iter->cpu, iter->started))
2566 if (per_cpu_ptr(iter->trace_buffer->data, iter->cpu)->skipped_entries)
2569 cpumask_set_cpu(iter->cpu, iter->started);
2571 /* Don't print started cpu buffer for the first entry of the trace */
2573 trace_seq_printf(s, "##### CPU %u buffer started ####\n",
2577 static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
2579 struct trace_seq *s = &iter->seq;
2580 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
2581 struct trace_entry *entry;
2582 struct trace_event *event;
2586 test_cpu_buff_start(iter);
2588 event = ftrace_find_event(entry->type);
2590 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
2591 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
2592 if (!trace_print_lat_context(iter))
2595 if (!trace_print_context(iter))
2601 return event->funcs->trace(iter, sym_flags, event);
2603 if (!trace_seq_printf(s, "Unknown type %d\n", entry->type))
2606 return TRACE_TYPE_HANDLED;
2608 return TRACE_TYPE_PARTIAL_LINE;
2611 static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
2613 struct trace_seq *s = &iter->seq;
2614 struct trace_entry *entry;
2615 struct trace_event *event;
2619 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
2620 if (!trace_seq_printf(s, "%d %d %llu ",
2621 entry->pid, iter->cpu, iter->ts))
2625 event = ftrace_find_event(entry->type);
2627 return event->funcs->raw(iter, 0, event);
2629 if (!trace_seq_printf(s, "%d ?\n", entry->type))
2632 return TRACE_TYPE_HANDLED;
2634 return TRACE_TYPE_PARTIAL_LINE;
2637 static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
2639 struct trace_seq *s = &iter->seq;
2640 unsigned char newline = '\n';
2641 struct trace_entry *entry;
2642 struct trace_event *event;
2646 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
2647 SEQ_PUT_HEX_FIELD_RET(s, entry->pid);
2648 SEQ_PUT_HEX_FIELD_RET(s, iter->cpu);
2649 SEQ_PUT_HEX_FIELD_RET(s, iter->ts);
2652 event = ftrace_find_event(entry->type);
2654 enum print_line_t ret = event->funcs->hex(iter, 0, event);
2655 if (ret != TRACE_TYPE_HANDLED)
2659 SEQ_PUT_FIELD_RET(s, newline);
2661 return TRACE_TYPE_HANDLED;
2664 static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
2666 struct trace_seq *s = &iter->seq;
2667 struct trace_entry *entry;
2668 struct trace_event *event;
2672 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
2673 SEQ_PUT_FIELD_RET(s, entry->pid);
2674 SEQ_PUT_FIELD_RET(s, iter->cpu);
2675 SEQ_PUT_FIELD_RET(s, iter->ts);
2678 event = ftrace_find_event(entry->type);
2679 return event ? event->funcs->binary(iter, 0, event) :
2683 int trace_empty(struct trace_iterator *iter)
2685 struct ring_buffer_iter *buf_iter;
2688 /* If we are looking at one CPU buffer, only check that one */
2689 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
2690 cpu = iter->cpu_file;
2691 buf_iter = trace_buffer_iter(iter, cpu);
2693 if (!ring_buffer_iter_empty(buf_iter))
2696 if (!ring_buffer_empty_cpu(iter->trace_buffer->buffer, cpu))
2702 for_each_tracing_cpu(cpu) {
2703 buf_iter = trace_buffer_iter(iter, cpu);
2705 if (!ring_buffer_iter_empty(buf_iter))
2708 if (!ring_buffer_empty_cpu(iter->trace_buffer->buffer, cpu))
2716 /* Called with trace_event_read_lock() held. */
2717 enum print_line_t print_trace_line(struct trace_iterator *iter)
2719 enum print_line_t ret;
2721 if (iter->lost_events &&
2722 !trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
2723 iter->cpu, iter->lost_events))
2724 return TRACE_TYPE_PARTIAL_LINE;
2726 if (iter->trace && iter->trace->print_line) {
2727 ret = iter->trace->print_line(iter);
2728 if (ret != TRACE_TYPE_UNHANDLED)
2732 if (iter->ent->type == TRACE_BPUTS &&
2733 trace_flags & TRACE_ITER_PRINTK &&
2734 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
2735 return trace_print_bputs_msg_only(iter);
2737 if (iter->ent->type == TRACE_BPRINT &&
2738 trace_flags & TRACE_ITER_PRINTK &&
2739 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
2740 return trace_print_bprintk_msg_only(iter);
2742 if (iter->ent->type == TRACE_PRINT &&
2743 trace_flags & TRACE_ITER_PRINTK &&
2744 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
2745 return trace_print_printk_msg_only(iter);
2747 if (trace_flags & TRACE_ITER_BIN)
2748 return print_bin_fmt(iter);
2750 if (trace_flags & TRACE_ITER_HEX)
2751 return print_hex_fmt(iter);
2753 if (trace_flags & TRACE_ITER_RAW)
2754 return print_raw_fmt(iter);
2756 return print_trace_fmt(iter);
2759 void trace_latency_header(struct seq_file *m)
2761 struct trace_iterator *iter = m->private;
2763 /* print nothing if the buffers are empty */
2764 if (trace_empty(iter))
2767 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
2768 print_trace_header(m, iter);
2770 if (!(trace_flags & TRACE_ITER_VERBOSE))
2771 print_lat_help_header(m);
2774 void trace_default_header(struct seq_file *m)
2776 struct trace_iterator *iter = m->private;
2778 if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
2781 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
2782 /* print nothing if the buffers are empty */
2783 if (trace_empty(iter))
2785 print_trace_header(m, iter);
2786 if (!(trace_flags & TRACE_ITER_VERBOSE))
2787 print_lat_help_header(m);
2789 if (!(trace_flags & TRACE_ITER_VERBOSE)) {
2790 if (trace_flags & TRACE_ITER_IRQ_INFO)
2791 if (trace_flags & TRACE_ITER_TGID)
2792 print_func_help_header_irq_tgid(iter->trace_buffer, m);
2794 print_func_help_header_irq(iter->trace_buffer, m);
2796 if (trace_flags & TRACE_ITER_TGID)
2797 print_func_help_header_tgid(iter->trace_buffer, m);
2799 print_func_help_header(iter->trace_buffer, m);
2804 static void test_ftrace_alive(struct seq_file *m)
2806 if (!ftrace_is_dead())
2808 seq_printf(m, "# WARNING: FUNCTION TRACING IS CORRUPTED\n");
2809 seq_printf(m, "# MAY BE MISSING FUNCTION EVENTS\n");
2812 #ifdef CONFIG_TRACER_MAX_TRACE
2813 static void show_snapshot_main_help(struct seq_file *m)
2815 seq_printf(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n");
2816 seq_printf(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n");
2817 seq_printf(m, "# Takes a snapshot of the main buffer.\n");
2818 seq_printf(m, "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate)\n");
2819 seq_printf(m, "# (Doesn't have to be '2' works with any number that\n");
2820 seq_printf(m, "# is not a '0' or '1')\n");
2823 static void show_snapshot_percpu_help(struct seq_file *m)
2825 seq_printf(m, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n");
2826 #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
2827 seq_printf(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n");
2828 seq_printf(m, "# Takes a snapshot of the main buffer for this cpu.\n");
2830 seq_printf(m, "# echo 1 > snapshot : Not supported with this kernel.\n");
2831 seq_printf(m, "# Must use main snapshot file to allocate.\n");
2833 seq_printf(m, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n");
2834 seq_printf(m, "# (Doesn't have to be '2' works with any number that\n");
2835 seq_printf(m, "# is not a '0' or '1')\n");
2838 static void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter)
2840 if (iter->tr->allocated_snapshot)
2841 seq_printf(m, "#\n# * Snapshot is allocated *\n#\n");
2843 seq_printf(m, "#\n# * Snapshot is freed *\n#\n");
2845 seq_printf(m, "# Snapshot commands:\n");
2846 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
2847 show_snapshot_main_help(m);
2849 show_snapshot_percpu_help(m);
2852 /* Should never be called */
2853 static inline void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter) { }
2856 static int s_show(struct seq_file *m, void *v)
2858 struct trace_iterator *iter = v;
2861 if (iter->ent == NULL) {
2863 seq_printf(m, "# tracer: %s\n", iter->trace->name);
2865 test_ftrace_alive(m);
2867 if (iter->snapshot && trace_empty(iter))
2868 print_snapshot_help(m, iter);
2869 else if (iter->trace && iter->trace->print_header)
2870 iter->trace->print_header(m);
2872 trace_default_header(m);
2874 } else if (iter->leftover) {
2876 * If we filled the seq_file buffer earlier, we
2877 * want to just show it now.
2879 ret = trace_print_seq(m, &iter->seq);
2881 /* ret should this time be zero, but you never know */
2882 iter->leftover = ret;
2885 print_trace_line(iter);
2886 ret = trace_print_seq(m, &iter->seq);
2888 * If we overflow the seq_file buffer, then it will
2889 * ask us for this data again at start up.
2891 * ret is 0 if seq_file write succeeded.
2894 iter->leftover = ret;
2901 * Should be used after trace_array_get(), trace_types_lock
2902 * ensures that i_cdev was already initialized.
2904 static inline int tracing_get_cpu(struct inode *inode)
2906 if (inode->i_cdev) /* See trace_create_cpu_file() */
2907 return (long)inode->i_cdev - 1;
2908 return RING_BUFFER_ALL_CPUS;
2911 static const struct seq_operations tracer_seq_ops = {
2918 static struct trace_iterator *
2919 __tracing_open(struct inode *inode, struct file *file, bool snapshot)
2921 struct trace_array *tr = inode->i_private;
2922 struct trace_iterator *iter;
2925 if (tracing_disabled)
2926 return ERR_PTR(-ENODEV);
2928 iter = __seq_open_private(file, &tracer_seq_ops, sizeof(*iter));
2930 return ERR_PTR(-ENOMEM);
2932 iter->buffer_iter = kzalloc(sizeof(*iter->buffer_iter) * num_possible_cpus(),
2934 if (!iter->buffer_iter)
2938 * We make a copy of the current tracer to avoid concurrent
2939 * changes on it while we are reading.
2941 mutex_lock(&trace_types_lock);
2942 iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL);
2946 *iter->trace = *tr->current_trace;
2948 if (!zalloc_cpumask_var(&iter->started, GFP_KERNEL))
2953 #ifdef CONFIG_TRACER_MAX_TRACE
2954 /* Currently only the top directory has a snapshot */
2955 if (tr->current_trace->print_max || snapshot)
2956 iter->trace_buffer = &tr->max_buffer;
2959 iter->trace_buffer = &tr->trace_buffer;
2960 iter->snapshot = snapshot;
2962 iter->cpu_file = tracing_get_cpu(inode);
2963 mutex_init(&iter->mutex);
2965 /* Notify the tracer early; before we stop tracing. */
2966 if (iter->trace && iter->trace->open)
2967 iter->trace->open(iter);
2969 /* Annotate start of buffers if we had overruns */
2970 if (ring_buffer_overruns(iter->trace_buffer->buffer))
2971 iter->iter_flags |= TRACE_FILE_ANNOTATE;
2973 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
2974 if (trace_clocks[tr->clock_id].in_ns)
2975 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
2977 /* stop the trace while dumping if we are not opening "snapshot" */
2978 if (!iter->snapshot)
2979 tracing_stop_tr(tr);
2981 if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
2982 for_each_tracing_cpu(cpu) {
2983 iter->buffer_iter[cpu] =
2984 ring_buffer_read_prepare(iter->trace_buffer->buffer, cpu);
2986 ring_buffer_read_prepare_sync();
2987 for_each_tracing_cpu(cpu) {
2988 ring_buffer_read_start(iter->buffer_iter[cpu]);
2989 tracing_iter_reset(iter, cpu);
2992 cpu = iter->cpu_file;
2993 iter->buffer_iter[cpu] =
2994 ring_buffer_read_prepare(iter->trace_buffer->buffer, cpu);
2995 ring_buffer_read_prepare_sync();
2996 ring_buffer_read_start(iter->buffer_iter[cpu]);
2997 tracing_iter_reset(iter, cpu);
3000 mutex_unlock(&trace_types_lock);
3005 mutex_unlock(&trace_types_lock);
3007 kfree(iter->buffer_iter);
3009 seq_release_private(inode, file);
3010 return ERR_PTR(-ENOMEM);
3013 int tracing_open_generic(struct inode *inode, struct file *filp)
3015 if (tracing_disabled)
3018 filp->private_data = inode->i_private;
3023 * Open and update trace_array ref count.
3024 * Must have the current trace_array passed to it.
3026 int tracing_open_generic_tr(struct inode *inode, struct file *filp)
3028 struct trace_array *tr = inode->i_private;
3030 if (tracing_disabled)
3033 if (trace_array_get(tr) < 0)
3036 filp->private_data = inode->i_private;
3041 static int tracing_release(struct inode *inode, struct file *file)
3043 struct trace_array *tr = inode->i_private;
3044 struct seq_file *m = file->private_data;
3045 struct trace_iterator *iter;
3048 if (!(file->f_mode & FMODE_READ)) {
3049 trace_array_put(tr);
3053 /* Writes do not use seq_file */
3055 mutex_lock(&trace_types_lock);
3057 for_each_tracing_cpu(cpu) {
3058 if (iter->buffer_iter[cpu])
3059 ring_buffer_read_finish(iter->buffer_iter[cpu]);
3062 if (iter->trace && iter->trace->close)
3063 iter->trace->close(iter);
3065 if (!iter->snapshot)
3066 /* reenable tracing if it was previously enabled */
3067 tracing_start_tr(tr);
3069 __trace_array_put(tr);
3071 mutex_unlock(&trace_types_lock);
3073 mutex_destroy(&iter->mutex);
3074 free_cpumask_var(iter->started);
3076 kfree(iter->buffer_iter);
3077 seq_release_private(inode, file);
3082 static int tracing_release_generic_tr(struct inode *inode, struct file *file)
3084 struct trace_array *tr = inode->i_private;
3086 trace_array_put(tr);
3090 static int tracing_single_release_tr(struct inode *inode, struct file *file)
3092 struct trace_array *tr = inode->i_private;
3094 trace_array_put(tr);
3096 return single_release(inode, file);
3099 static int tracing_open(struct inode *inode, struct file *file)
3101 struct trace_array *tr = inode->i_private;
3102 struct trace_iterator *iter;
3105 if (trace_array_get(tr) < 0)
3108 /* If this file was open for write, then erase contents */
3109 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
3110 int cpu = tracing_get_cpu(inode);
3112 if (cpu == RING_BUFFER_ALL_CPUS)
3113 tracing_reset_online_cpus(&tr->trace_buffer);
3115 tracing_reset(&tr->trace_buffer, cpu);
3118 if (file->f_mode & FMODE_READ) {
3119 iter = __tracing_open(inode, file, false);
3121 ret = PTR_ERR(iter);
3122 else if (trace_flags & TRACE_ITER_LATENCY_FMT)
3123 iter->iter_flags |= TRACE_FILE_LAT_FMT;
3127 trace_array_put(tr);
3133 t_next(struct seq_file *m, void *v, loff_t *pos)
3135 struct tracer *t = v;
3145 static void *t_start(struct seq_file *m, loff_t *pos)
3150 mutex_lock(&trace_types_lock);
3151 for (t = trace_types; t && l < *pos; t = t_next(m, t, &l))
3157 static void t_stop(struct seq_file *m, void *p)
3159 mutex_unlock(&trace_types_lock);
3162 static int t_show(struct seq_file *m, void *v)
3164 struct tracer *t = v;
3169 seq_printf(m, "%s", t->name);
3178 static const struct seq_operations show_traces_seq_ops = {
3185 static int show_traces_open(struct inode *inode, struct file *file)
3187 if (tracing_disabled)
3190 return seq_open(file, &show_traces_seq_ops);
3194 tracing_write_stub(struct file *filp, const char __user *ubuf,
3195 size_t count, loff_t *ppos)
3200 static loff_t tracing_seek(struct file *file, loff_t offset, int origin)
3202 if (file->f_mode & FMODE_READ)
3203 return seq_lseek(file, offset, origin);
3208 static const struct file_operations tracing_fops = {
3209 .open = tracing_open,
3211 .write = tracing_write_stub,
3212 .llseek = tracing_seek,
3213 .release = tracing_release,
3216 static const struct file_operations show_traces_fops = {
3217 .open = show_traces_open,
3219 .release = seq_release,
3220 .llseek = seq_lseek,
3224 * Only trace on a CPU if the bitmask is set:
3226 static cpumask_var_t tracing_cpumask;
3229 * The tracer itself will not take this lock, but still we want
3230 * to provide a consistent cpumask to user-space:
3232 static DEFINE_MUTEX(tracing_cpumask_update_lock);
3235 * Temporary storage for the character representation of the
3236 * CPU bitmask (and one more byte for the newline):
3238 static char mask_str[NR_CPUS + 1];
3241 tracing_cpumask_read(struct file *filp, char __user *ubuf,
3242 size_t count, loff_t *ppos)
3246 mutex_lock(&tracing_cpumask_update_lock);
3248 len = cpumask_scnprintf(mask_str, count, tracing_cpumask);
3249 if (count - len < 2) {
3253 len += sprintf(mask_str + len, "\n");
3254 count = simple_read_from_buffer(ubuf, count, ppos, mask_str, NR_CPUS+1);
3257 mutex_unlock(&tracing_cpumask_update_lock);
3263 tracing_cpumask_write(struct file *filp, const char __user *ubuf,
3264 size_t count, loff_t *ppos)
3266 struct trace_array *tr = filp->private_data;
3267 cpumask_var_t tracing_cpumask_new;
3270 if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
3273 err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
3277 mutex_lock(&tracing_cpumask_update_lock);
3279 local_irq_disable();
3280 arch_spin_lock(&ftrace_max_lock);
3281 for_each_tracing_cpu(cpu) {
3283 * Increase/decrease the disabled counter if we are
3284 * about to flip a bit in the cpumask:
3286 if (cpumask_test_cpu(cpu, tracing_cpumask) &&
3287 !cpumask_test_cpu(cpu, tracing_cpumask_new)) {
3288 atomic_inc(&per_cpu_ptr(tr->trace_buffer.data, cpu)->disabled);
3289 ring_buffer_record_disable_cpu(tr->trace_buffer.buffer, cpu);
3291 if (!cpumask_test_cpu(cpu, tracing_cpumask) &&
3292 cpumask_test_cpu(cpu, tracing_cpumask_new)) {
3293 atomic_dec(&per_cpu_ptr(tr->trace_buffer.data, cpu)->disabled);
3294 ring_buffer_record_enable_cpu(tr->trace_buffer.buffer, cpu);
3297 arch_spin_unlock(&ftrace_max_lock);
3300 cpumask_copy(tracing_cpumask, tracing_cpumask_new);
3302 mutex_unlock(&tracing_cpumask_update_lock);
3303 free_cpumask_var(tracing_cpumask_new);
3308 free_cpumask_var(tracing_cpumask_new);
3313 static const struct file_operations tracing_cpumask_fops = {
3314 .open = tracing_open_generic,
3315 .read = tracing_cpumask_read,
3316 .write = tracing_cpumask_write,
3317 .llseek = generic_file_llseek,
3320 static int tracing_trace_options_show(struct seq_file *m, void *v)
3322 struct tracer_opt *trace_opts;
3323 struct trace_array *tr = m->private;
3327 mutex_lock(&trace_types_lock);
3328 tracer_flags = tr->current_trace->flags->val;
3329 trace_opts = tr->current_trace->flags->opts;
3331 for (i = 0; trace_options[i]; i++) {
3332 if (trace_flags & (1 << i))
3333 seq_printf(m, "%s\n", trace_options[i]);
3335 seq_printf(m, "no%s\n", trace_options[i]);
3338 for (i = 0; trace_opts[i].name; i++) {
3339 if (tracer_flags & trace_opts[i].bit)
3340 seq_printf(m, "%s\n", trace_opts[i].name);
3342 seq_printf(m, "no%s\n", trace_opts[i].name);
3344 mutex_unlock(&trace_types_lock);
3349 static int __set_tracer_option(struct tracer *trace,
3350 struct tracer_flags *tracer_flags,
3351 struct tracer_opt *opts, int neg)
3355 ret = trace->set_flag(tracer_flags->val, opts->bit, !neg);
3360 tracer_flags->val &= ~opts->bit;
3362 tracer_flags->val |= opts->bit;
3366 /* Try to assign a tracer specific option */
3367 static int set_tracer_option(struct tracer *trace, char *cmp, int neg)
3369 struct tracer_flags *tracer_flags = trace->flags;
3370 struct tracer_opt *opts = NULL;
3373 for (i = 0; tracer_flags->opts[i].name; i++) {
3374 opts = &tracer_flags->opts[i];
3376 if (strcmp(cmp, opts->name) == 0)
3377 return __set_tracer_option(trace, trace->flags,
3384 /* Some tracers require overwrite to stay enabled */
3385 int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set)
3387 if (tracer->enabled && (mask & TRACE_ITER_OVERWRITE) && !set)
3393 int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled)
3395 /* do nothing if flag is already set */
3396 if (!!(trace_flags & mask) == !!enabled)
3399 /* Give the tracer a chance to approve the change */
3400 if (tr->current_trace->flag_changed)
3401 if (tr->current_trace->flag_changed(tr->current_trace, mask, !!enabled))
3405 trace_flags |= mask;
3407 trace_flags &= ~mask;
3409 if (mask == TRACE_ITER_RECORD_CMD)
3410 trace_event_enable_cmd_record(enabled);
3412 if (mask == TRACE_ITER_OVERWRITE) {
3413 ring_buffer_change_overwrite(tr->trace_buffer.buffer, enabled);
3414 #ifdef CONFIG_TRACER_MAX_TRACE
3415 ring_buffer_change_overwrite(tr->max_buffer.buffer, enabled);
3419 if (mask == TRACE_ITER_PRINTK)
3420 trace_printk_start_stop_comm(enabled);
3425 static int trace_set_options(struct trace_array *tr, char *option)
3432 cmp = strstrip(option);
3434 if (strncmp(cmp, "no", 2) == 0) {
3439 mutex_lock(&trace_types_lock);
3441 for (i = 0; trace_options[i]; i++) {
3442 if (strcmp(cmp, trace_options[i]) == 0) {
3443 ret = set_tracer_flag(tr, 1 << i, !neg);
3448 /* If no option could be set, test the specific tracer options */
3449 if (!trace_options[i])
3450 ret = set_tracer_option(tr->current_trace, cmp, neg);
3452 mutex_unlock(&trace_types_lock);
3458 tracing_trace_options_write(struct file *filp, const char __user *ubuf,
3459 size_t cnt, loff_t *ppos)
3461 struct seq_file *m = filp->private_data;
3462 struct trace_array *tr = m->private;
3466 if (cnt >= sizeof(buf))
3469 if (copy_from_user(&buf, ubuf, cnt))
3474 ret = trace_set_options(tr, buf);
3483 static int tracing_trace_options_open(struct inode *inode, struct file *file)
3485 struct trace_array *tr = inode->i_private;
3488 if (tracing_disabled)
3491 if (trace_array_get(tr) < 0)
3494 ret = single_open(file, tracing_trace_options_show, inode->i_private);
3496 trace_array_put(tr);
3501 static const struct file_operations tracing_iter_fops = {
3502 .open = tracing_trace_options_open,
3504 .llseek = seq_lseek,
3505 .release = tracing_single_release_tr,
3506 .write = tracing_trace_options_write,
3509 static const char readme_msg[] =
3510 "tracing mini-HOWTO:\n\n"
3511 "# echo 0 > tracing_on : quick way to disable tracing\n"
3512 "# echo 1 > tracing_on : quick way to re-enable tracing\n\n"
3513 " Important files:\n"
3514 " trace\t\t\t- The static contents of the buffer\n"
3515 "\t\t\t To clear the buffer write into this file: echo > trace\n"
3516 " trace_pipe\t\t- A consuming read to see the contents of the buffer\n"
3517 " current_tracer\t- function and latency tracers\n"
3518 " available_tracers\t- list of configured tracers for current_tracer\n"
3519 " buffer_size_kb\t- view and modify size of per cpu buffer\n"
3520 " buffer_total_size_kb - view total size of all cpu buffers\n\n"
3521 " trace_clock\t\t-change the clock used to order events\n"
3522 " local: Per cpu clock but may not be synced across CPUs\n"
3523 " global: Synced across CPUs but slows tracing down.\n"
3524 " counter: Not a clock, but just an increment\n"
3525 " uptime: Jiffy counter from time of boot\n"
3526 " perf: Same clock that perf events use\n"
3527 #ifdef CONFIG_X86_64
3528 " x86-tsc: TSC cycle counter\n"
3530 "\n trace_marker\t\t- Writes into this file writes into the kernel buffer\n"
3531 " tracing_cpumask\t- Limit which CPUs to trace\n"
3532 " instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
3533 "\t\t\t Remove sub-buffer with rmdir\n"
3534 " trace_options\t\t- Set format or modify how tracing happens\n"
3535 "\t\t\t Disable an option by adding a suffix 'no' to the option name\n"
3536 #ifdef CONFIG_DYNAMIC_FTRACE
3537 "\n available_filter_functions - list of functions that can be filtered on\n"
3538 " set_ftrace_filter\t- echo function name in here to only trace these functions\n"
3539 " accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
3540 " modules: Can select a group via module\n"
3541 " Format: :mod:<module-name>\n"
3542 " example: echo :mod:ext3 > set_ftrace_filter\n"
3543 " triggers: a command to perform when function is hit\n"
3544 " Format: <function>:<trigger>[:count]\n"
3545 " trigger: traceon, traceoff\n"
3546 " enable_event:<system>:<event>\n"
3547 " disable_event:<system>:<event>\n"
3548 #ifdef CONFIG_STACKTRACE
3551 #ifdef CONFIG_TRACER_SNAPSHOT
3554 " example: echo do_fault:traceoff > set_ftrace_filter\n"
3555 " echo do_trap:traceoff:3 > set_ftrace_filter\n"
3556 " The first one will disable tracing every time do_fault is hit\n"
3557 " The second will disable tracing at most 3 times when do_trap is hit\n"
3558 " The first time do trap is hit and it disables tracing, the counter\n"
3559 " will decrement to 2. If tracing is already disabled, the counter\n"
3560 " will not decrement. It only decrements when the trigger did work\n"
3561 " To remove trigger without count:\n"
3562 " echo '!<function>:<trigger> > set_ftrace_filter\n"
3563 " To remove trigger with a count:\n"
3564 " echo '!<function>:<trigger>:0 > set_ftrace_filter\n"
3565 " set_ftrace_notrace\t- echo function name in here to never trace.\n"
3566 " accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
3567 " modules: Can select a group via module command :mod:\n"
3568 " Does not accept triggers\n"
3569 #endif /* CONFIG_DYNAMIC_FTRACE */
3570 #ifdef CONFIG_FUNCTION_TRACER
3571 " set_ftrace_pid\t- Write pid(s) to only function trace those pids (function)\n"
3573 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3574 " set_graph_function\t- Trace the nested calls of a function (function_graph)\n"
3575 " max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n"
3577 #ifdef CONFIG_TRACER_SNAPSHOT
3578 "\n snapshot\t\t- Like 'trace' but shows the content of the static snapshot buffer\n"
3579 "\t\t\t Read the contents for more information\n"
3581 #ifdef CONFIG_STACKTRACE
3582 " stack_trace\t\t- Shows the max stack trace when active\n"
3583 " stack_max_size\t- Shows current max stack size that was traced\n"
3584 "\t\t\t Write into this file to reset the max size (trigger a new trace)\n"
3585 #ifdef CONFIG_DYNAMIC_FTRACE
3586 " stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace traces\n"
3588 #endif /* CONFIG_STACKTRACE */
3592 tracing_readme_read(struct file *filp, char __user *ubuf,
3593 size_t cnt, loff_t *ppos)
3595 return simple_read_from_buffer(ubuf, cnt, ppos,
3596 readme_msg, strlen(readme_msg));
3599 static const struct file_operations tracing_readme_fops = {
3600 .open = tracing_open_generic,
3601 .read = tracing_readme_read,
3602 .llseek = generic_file_llseek,
3606 tracing_saved_cmdlines_read(struct file *file, char __user *ubuf,
3607 size_t cnt, loff_t *ppos)
3616 file_buf = kmalloc(SAVED_CMDLINES*(16+TASK_COMM_LEN), GFP_KERNEL);
3620 buf_comm = kmalloc(TASK_COMM_LEN, GFP_KERNEL);
3628 for (i = 0; i < SAVED_CMDLINES; i++) {
3631 pid = map_cmdline_to_pid[i];
3632 if (pid == -1 || pid == NO_CMDLINE_MAP)
3635 trace_find_cmdline(pid, buf_comm);
3636 r = sprintf(buf, "%d %s\n", pid, buf_comm);
3641 len = simple_read_from_buffer(ubuf, cnt, ppos,
3650 static const struct file_operations tracing_saved_cmdlines_fops = {
3651 .open = tracing_open_generic,
3652 .read = tracing_saved_cmdlines_read,
3653 .llseek = generic_file_llseek,
3657 tracing_saved_tgids_read(struct file *file, char __user *ubuf,
3658 size_t cnt, loff_t *ppos)
3666 file_buf = kmalloc(SAVED_CMDLINES*(16+1+16), GFP_KERNEL);
3672 for (i = 0; i < SAVED_CMDLINES; i++) {
3676 pid = map_cmdline_to_pid[i];
3677 if (pid == -1 || pid == NO_CMDLINE_MAP)
3680 tgid = trace_find_tgid(pid);
3681 r = sprintf(buf, "%d %d\n", pid, tgid);
3686 len = simple_read_from_buffer(ubuf, cnt, ppos,
3694 static const struct file_operations tracing_saved_tgids_fops = {
3695 .open = tracing_open_generic,
3696 .read = tracing_saved_tgids_read,
3697 .llseek = generic_file_llseek,
3701 tracing_set_trace_read(struct file *filp, char __user *ubuf,
3702 size_t cnt, loff_t *ppos)
3704 struct trace_array *tr = filp->private_data;
3705 char buf[MAX_TRACER_SIZE+2];
3708 mutex_lock(&trace_types_lock);
3709 r = sprintf(buf, "%s\n", tr->current_trace->name);
3710 mutex_unlock(&trace_types_lock);
3712 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
3715 int tracer_init(struct tracer *t, struct trace_array *tr)
3717 tracing_reset_online_cpus(&tr->trace_buffer);
3721 static void set_buffer_entries(struct trace_buffer *buf, unsigned long val)
3725 for_each_tracing_cpu(cpu)
3726 per_cpu_ptr(buf->data, cpu)->entries = val;
3729 #ifdef CONFIG_TRACER_MAX_TRACE
3730 /* resize @tr's buffer to the size of @size_tr's entries */
3731 static int resize_buffer_duplicate_size(struct trace_buffer *trace_buf,
3732 struct trace_buffer *size_buf, int cpu_id)
3736 if (cpu_id == RING_BUFFER_ALL_CPUS) {
3737 for_each_tracing_cpu(cpu) {
3738 ret = ring_buffer_resize(trace_buf->buffer,
3739 per_cpu_ptr(size_buf->data, cpu)->entries, cpu);
3742 per_cpu_ptr(trace_buf->data, cpu)->entries =
3743 per_cpu_ptr(size_buf->data, cpu)->entries;
3746 ret = ring_buffer_resize(trace_buf->buffer,
3747 per_cpu_ptr(size_buf->data, cpu_id)->entries, cpu_id);
3749 per_cpu_ptr(trace_buf->data, cpu_id)->entries =
3750 per_cpu_ptr(size_buf->data, cpu_id)->entries;
3755 #endif /* CONFIG_TRACER_MAX_TRACE */
3757 static int __tracing_resize_ring_buffer(struct trace_array *tr,
3758 unsigned long size, int cpu)
3763 * If kernel or user changes the size of the ring buffer
3764 * we use the size that was given, and we can forget about
3765 * expanding it later.
3767 ring_buffer_expanded = true;
3769 /* May be called before buffers are initialized */
3770 if (!tr->trace_buffer.buffer)
3773 ret = ring_buffer_resize(tr->trace_buffer.buffer, size, cpu);
3777 #ifdef CONFIG_TRACER_MAX_TRACE
3778 if (!(tr->flags & TRACE_ARRAY_FL_GLOBAL) ||
3779 !tr->current_trace->use_max_tr)
3782 ret = ring_buffer_resize(tr->max_buffer.buffer, size, cpu);
3784 int r = resize_buffer_duplicate_size(&tr->trace_buffer,
3785 &tr->trace_buffer, cpu);
3788 * AARGH! We are left with different
3789 * size max buffer!!!!
3790 * The max buffer is our "snapshot" buffer.
3791 * When a tracer needs a snapshot (one of the
3792 * latency tracers), it swaps the max buffer
3793 * with the saved snap shot. We succeeded to
3794 * update the size of the main buffer, but failed to
3795 * update the size of the max buffer. But when we tried
3796 * to reset the main buffer to the original size, we
3797 * failed there too. This is very unlikely to
3798 * happen, but if it does, warn and kill all
3802 tracing_disabled = 1;
3807 if (cpu == RING_BUFFER_ALL_CPUS)
3808 set_buffer_entries(&tr->max_buffer, size);
3810 per_cpu_ptr(tr->max_buffer.data, cpu)->entries = size;
3813 #endif /* CONFIG_TRACER_MAX_TRACE */
3815 if (cpu == RING_BUFFER_ALL_CPUS)
3816 set_buffer_entries(&tr->trace_buffer, size);
3818 per_cpu_ptr(tr->trace_buffer.data, cpu)->entries = size;
3823 static ssize_t tracing_resize_ring_buffer(struct trace_array *tr,
3824 unsigned long size, int cpu_id)
3828 mutex_lock(&trace_types_lock);
3830 if (cpu_id != RING_BUFFER_ALL_CPUS) {
3831 /* make sure, this cpu is enabled in the mask */
3832 if (!cpumask_test_cpu(cpu_id, tracing_buffer_mask)) {
3838 ret = __tracing_resize_ring_buffer(tr, size, cpu_id);
3843 mutex_unlock(&trace_types_lock);
3850 * tracing_update_buffers - used by tracing facility to expand ring buffers
3852 * To save on memory when the tracing is never used on a system with it
3853 * configured in. The ring buffers are set to a minimum size. But once
3854 * a user starts to use the tracing facility, then they need to grow
3855 * to their default size.
3857 * This function is to be called when a tracer is about to be used.
3859 int tracing_update_buffers(void)
3863 mutex_lock(&trace_types_lock);
3864 if (!ring_buffer_expanded)
3865 ret = __tracing_resize_ring_buffer(&global_trace, trace_buf_size,
3866 RING_BUFFER_ALL_CPUS);
3867 mutex_unlock(&trace_types_lock);
3872 struct trace_option_dentry;
3874 static struct trace_option_dentry *
3875 create_trace_option_files(struct trace_array *tr, struct tracer *tracer);
3878 destroy_trace_option_files(struct trace_option_dentry *topts);
3880 static int tracing_set_tracer(const char *buf)
3882 static struct trace_option_dentry *topts;
3883 struct trace_array *tr = &global_trace;
3885 #ifdef CONFIG_TRACER_MAX_TRACE
3890 mutex_lock(&trace_types_lock);
3892 if (!ring_buffer_expanded) {
3893 ret = __tracing_resize_ring_buffer(tr, trace_buf_size,
3894 RING_BUFFER_ALL_CPUS);
3900 for (t = trace_types; t; t = t->next) {
3901 if (strcmp(t->name, buf) == 0)
3908 if (t == tr->current_trace)
3911 trace_branch_disable();
3913 tr->current_trace->enabled = false;
3915 if (tr->current_trace->reset)
3916 tr->current_trace->reset(tr);
3918 /* Current trace needs to be nop_trace before synchronize_sched */
3919 tr->current_trace = &nop_trace;
3921 #ifdef CONFIG_TRACER_MAX_TRACE
3922 had_max_tr = tr->allocated_snapshot;
3924 if (had_max_tr && !t->use_max_tr) {
3926 * We need to make sure that the update_max_tr sees that
3927 * current_trace changed to nop_trace to keep it from
3928 * swapping the buffers after we resize it.
3929 * The update_max_tr is called from interrupts disabled
3930 * so a synchronized_sched() is sufficient.
3932 synchronize_sched();
3936 destroy_trace_option_files(topts);
3938 topts = create_trace_option_files(tr, t);
3940 #ifdef CONFIG_TRACER_MAX_TRACE
3941 if (t->use_max_tr && !had_max_tr) {
3942 ret = alloc_snapshot(tr);
3949 ret = tracer_init(t, tr);
3954 tr->current_trace = t;
3955 tr->current_trace->enabled = true;
3956 trace_branch_enable(tr);
3958 mutex_unlock(&trace_types_lock);
3964 tracing_set_trace_write(struct file *filp, const char __user *ubuf,
3965 size_t cnt, loff_t *ppos)
3967 char buf[MAX_TRACER_SIZE+1];
3974 if (cnt > MAX_TRACER_SIZE)
3975 cnt = MAX_TRACER_SIZE;
3977 if (copy_from_user(&buf, ubuf, cnt))
3982 /* strip ending whitespace. */
3983 for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
3986 err = tracing_set_tracer(buf);
3996 tracing_max_lat_read(struct file *filp, char __user *ubuf,
3997 size_t cnt, loff_t *ppos)
3999 unsigned long *ptr = filp->private_data;
4003 r = snprintf(buf, sizeof(buf), "%ld\n",
4004 *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
4005 if (r > sizeof(buf))
4007 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
4011 tracing_max_lat_write(struct file *filp, const char __user *ubuf,
4012 size_t cnt, loff_t *ppos)
4014 unsigned long *ptr = filp->private_data;
4018 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
4027 static int tracing_open_pipe(struct inode *inode, struct file *filp)
4029 struct trace_array *tr = inode->i_private;
4030 struct trace_iterator *iter;
4033 if (tracing_disabled)
4036 if (trace_array_get(tr) < 0)
4039 mutex_lock(&trace_types_lock);
4041 /* create a buffer to store the information to pass to userspace */
4042 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
4045 __trace_array_put(tr);
4050 * We make a copy of the current tracer to avoid concurrent
4051 * changes on it while we are reading.
4053 iter->trace = kmalloc(sizeof(*iter->trace), GFP_KERNEL);
4058 *iter->trace = *tr->current_trace;
4060 if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
4065 /* trace pipe does not show start of buffer */
4066 cpumask_setall(iter->started);
4068 if (trace_flags & TRACE_ITER_LATENCY_FMT)
4069 iter->iter_flags |= TRACE_FILE_LAT_FMT;
4071 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
4072 if (trace_clocks[tr->clock_id].in_ns)
4073 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
4076 iter->trace_buffer = &tr->trace_buffer;
4077 iter->cpu_file = tracing_get_cpu(inode);
4078 mutex_init(&iter->mutex);
4079 filp->private_data = iter;
4081 if (iter->trace->pipe_open)
4082 iter->trace->pipe_open(iter);
4084 nonseekable_open(inode, filp);
4086 mutex_unlock(&trace_types_lock);
4092 __trace_array_put(tr);
4093 mutex_unlock(&trace_types_lock);
4097 static int tracing_release_pipe(struct inode *inode, struct file *file)
4099 struct trace_iterator *iter = file->private_data;
4100 struct trace_array *tr = inode->i_private;
4102 mutex_lock(&trace_types_lock);
4104 if (iter->trace->pipe_close)
4105 iter->trace->pipe_close(iter);
4107 mutex_unlock(&trace_types_lock);
4109 free_cpumask_var(iter->started);
4110 mutex_destroy(&iter->mutex);
4114 trace_array_put(tr);
4120 trace_poll(struct trace_iterator *iter, struct file *filp, poll_table *poll_table)
4122 /* Iterators are static, they should be filled or empty */
4123 if (trace_buffer_iter(iter, iter->cpu_file))
4124 return POLLIN | POLLRDNORM;
4126 if (trace_flags & TRACE_ITER_BLOCK)
4128 * Always select as readable when in blocking mode
4130 return POLLIN | POLLRDNORM;
4132 return ring_buffer_poll_wait(iter->trace_buffer->buffer, iter->cpu_file,
4137 tracing_poll_pipe(struct file *filp, poll_table *poll_table)
4139 struct trace_iterator *iter = filp->private_data;
4141 return trace_poll(iter, filp, poll_table);
4145 * This is a make-shift waitqueue.
4146 * A tracer might use this callback on some rare cases:
4148 * 1) the current tracer might hold the runqueue lock when it wakes up
4149 * a reader, hence a deadlock (sched, function, and function graph tracers)
4150 * 2) the function tracers, trace all functions, we don't want
4151 * the overhead of calling wake_up and friends
4152 * (and tracing them too)
4154 * Anyway, this is really very primitive wakeup.
4156 int poll_wait_pipe(struct trace_iterator *iter)
4158 set_current_state(TASK_INTERRUPTIBLE);
4159 /* sleep for 100 msecs, and try again. */
4160 schedule_timeout(HZ / 10);
4164 /* Must be called with trace_types_lock mutex held. */
4165 static int tracing_wait_pipe(struct file *filp)
4167 struct trace_iterator *iter = filp->private_data;
4170 while (trace_empty(iter)) {
4172 if ((filp->f_flags & O_NONBLOCK)) {
4176 mutex_unlock(&iter->mutex);
4178 ret = iter->trace->wait_pipe(iter);
4180 mutex_lock(&iter->mutex);
4185 if (signal_pending(current))
4189 * We block until we read something and tracing is disabled.
4190 * We still block if tracing is disabled, but we have never
4191 * read anything. This allows a user to cat this file, and
4192 * then enable tracing. But after we have read something,
4193 * we give an EOF when tracing is again disabled.
4195 * iter->pos will be 0 if we haven't read anything.
4197 if (!tracing_is_on() && iter->pos)
4208 tracing_read_pipe(struct file *filp, char __user *ubuf,
4209 size_t cnt, loff_t *ppos)
4211 struct trace_iterator *iter = filp->private_data;
4212 struct trace_array *tr = iter->tr;
4215 /* return any leftover data */
4216 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
4220 trace_seq_init(&iter->seq);
4222 /* copy the tracer to avoid using a global lock all around */
4223 mutex_lock(&trace_types_lock);
4224 if (unlikely(iter->trace->name != tr->current_trace->name))
4225 *iter->trace = *tr->current_trace;
4226 mutex_unlock(&trace_types_lock);
4229 * Avoid more than one consumer on a single file descriptor
4230 * This is just a matter of traces coherency, the ring buffer itself
4233 mutex_lock(&iter->mutex);
4234 if (iter->trace->read) {
4235 sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
4241 sret = tracing_wait_pipe(filp);
4245 /* stop when tracing is finished */
4246 if (trace_empty(iter)) {
4251 if (cnt >= PAGE_SIZE)
4252 cnt = PAGE_SIZE - 1;
4254 /* reset all but tr, trace, and overruns */
4255 memset(&iter->seq, 0,
4256 sizeof(struct trace_iterator) -
4257 offsetof(struct trace_iterator, seq));
4258 cpumask_clear(iter->started);
4261 trace_event_read_lock();
4262 trace_access_lock(iter->cpu_file);
4263 while (trace_find_next_entry_inc(iter) != NULL) {
4264 enum print_line_t ret;
4265 int len = iter->seq.len;
4267 ret = print_trace_line(iter);
4268 if (ret == TRACE_TYPE_PARTIAL_LINE) {
4269 /* don't print partial lines */
4270 iter->seq.len = len;
4273 if (ret != TRACE_TYPE_NO_CONSUME)
4274 trace_consume(iter);
4276 if (iter->seq.len >= cnt)
4280 * Setting the full flag means we reached the trace_seq buffer
4281 * size and we should leave by partial output condition above.
4282 * One of the trace_seq_* functions is not used properly.
4284 WARN_ONCE(iter->seq.full, "full flag set for trace type %d",
4287 trace_access_unlock(iter->cpu_file);
4288 trace_event_read_unlock();
4290 /* Now copy what we have to the user */
4291 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
4292 if (iter->seq.readpos >= iter->seq.len)
4293 trace_seq_init(&iter->seq);
4296 * If there was nothing to send to user, in spite of consuming trace
4297 * entries, go back to wait for more entries.
4303 mutex_unlock(&iter->mutex);
4308 static void tracing_pipe_buf_release(struct pipe_inode_info *pipe,
4309 struct pipe_buffer *buf)
4311 __free_page(buf->page);
4314 static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
4317 __free_page(spd->pages[idx]);
4320 static const struct pipe_buf_operations tracing_pipe_buf_ops = {
4322 .map = generic_pipe_buf_map,
4323 .unmap = generic_pipe_buf_unmap,
4324 .confirm = generic_pipe_buf_confirm,
4325 .release = tracing_pipe_buf_release,
4326 .steal = generic_pipe_buf_steal,
4327 .get = generic_pipe_buf_get,
4331 tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
4336 /* Seq buffer is page-sized, exactly what we need. */
4338 count = iter->seq.len;
4339 ret = print_trace_line(iter);
4340 count = iter->seq.len - count;
4343 iter->seq.len -= count;
4346 if (ret == TRACE_TYPE_PARTIAL_LINE) {
4347 iter->seq.len -= count;
4351 if (ret != TRACE_TYPE_NO_CONSUME)
4352 trace_consume(iter);
4354 if (!trace_find_next_entry_inc(iter)) {
4364 static ssize_t tracing_splice_read_pipe(struct file *filp,
4366 struct pipe_inode_info *pipe,
4370 struct page *pages_def[PIPE_DEF_BUFFERS];
4371 struct partial_page partial_def[PIPE_DEF_BUFFERS];
4372 struct trace_iterator *iter = filp->private_data;
4373 struct splice_pipe_desc spd = {
4375 .partial = partial_def,
4376 .nr_pages = 0, /* This gets updated below. */
4377 .nr_pages_max = PIPE_DEF_BUFFERS,
4379 .ops = &tracing_pipe_buf_ops,
4380 .spd_release = tracing_spd_release_pipe,
4382 struct trace_array *tr = iter->tr;
4387 if (splice_grow_spd(pipe, &spd))
4390 /* copy the tracer to avoid using a global lock all around */
4391 mutex_lock(&trace_types_lock);
4392 if (unlikely(iter->trace->name != tr->current_trace->name))
4393 *iter->trace = *tr->current_trace;
4394 mutex_unlock(&trace_types_lock);
4396 mutex_lock(&iter->mutex);
4398 if (iter->trace->splice_read) {
4399 ret = iter->trace->splice_read(iter, filp,
4400 ppos, pipe, len, flags);
4405 ret = tracing_wait_pipe(filp);
4409 if (!iter->ent && !trace_find_next_entry_inc(iter)) {
4414 trace_event_read_lock();
4415 trace_access_lock(iter->cpu_file);
4417 /* Fill as many pages as possible. */
4418 for (i = 0, rem = len; i < pipe->buffers && rem; i++) {
4419 spd.pages[i] = alloc_page(GFP_KERNEL);
4423 rem = tracing_fill_pipe_page(rem, iter);
4425 /* Copy the data into the page, so we can start over. */
4426 ret = trace_seq_to_buffer(&iter->seq,
4427 page_address(spd.pages[i]),
4430 __free_page(spd.pages[i]);
4433 spd.partial[i].offset = 0;
4434 spd.partial[i].len = iter->seq.len;
4436 trace_seq_init(&iter->seq);
4439 trace_access_unlock(iter->cpu_file);
4440 trace_event_read_unlock();
4441 mutex_unlock(&iter->mutex);
4445 ret = splice_to_pipe(pipe, &spd);
4447 splice_shrink_spd(&spd);
4451 mutex_unlock(&iter->mutex);
4456 tracing_entries_read(struct file *filp, char __user *ubuf,
4457 size_t cnt, loff_t *ppos)
4459 struct inode *inode = file_inode(filp);
4460 struct trace_array *tr = inode->i_private;
4461 int cpu = tracing_get_cpu(inode);
4466 mutex_lock(&trace_types_lock);
4468 if (cpu == RING_BUFFER_ALL_CPUS) {
4469 int cpu, buf_size_same;
4474 /* check if all cpu sizes are same */
4475 for_each_tracing_cpu(cpu) {
4476 /* fill in the size from first enabled cpu */
4478 size = per_cpu_ptr(tr->trace_buffer.data, cpu)->entries;
4479 if (size != per_cpu_ptr(tr->trace_buffer.data, cpu)->entries) {
4485 if (buf_size_same) {
4486 if (!ring_buffer_expanded)
4487 r = sprintf(buf, "%lu (expanded: %lu)\n",
4489 trace_buf_size >> 10);
4491 r = sprintf(buf, "%lu\n", size >> 10);
4493 r = sprintf(buf, "X\n");
4495 r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->trace_buffer.data, cpu)->entries >> 10);
4497 mutex_unlock(&trace_types_lock);
4499 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
4504 tracing_entries_write(struct file *filp, const char __user *ubuf,
4505 size_t cnt, loff_t *ppos)
4507 struct inode *inode = file_inode(filp);
4508 struct trace_array *tr = inode->i_private;
4512 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
4516 /* must have at least 1 entry */
4520 /* value is in KB */
4522 ret = tracing_resize_ring_buffer(tr, val, tracing_get_cpu(inode));
4532 tracing_total_entries_read(struct file *filp, char __user *ubuf,
4533 size_t cnt, loff_t *ppos)
4535 struct trace_array *tr = filp->private_data;
4538 unsigned long size = 0, expanded_size = 0;
4540 mutex_lock(&trace_types_lock);
4541 for_each_tracing_cpu(cpu) {
4542 size += per_cpu_ptr(tr->trace_buffer.data, cpu)->entries >> 10;
4543 if (!ring_buffer_expanded)
4544 expanded_size += trace_buf_size >> 10;
4546 if (ring_buffer_expanded)
4547 r = sprintf(buf, "%lu\n", size);
4549 r = sprintf(buf, "%lu (expanded: %lu)\n", size, expanded_size);
4550 mutex_unlock(&trace_types_lock);
4552 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
4556 tracing_free_buffer_write(struct file *filp, const char __user *ubuf,
4557 size_t cnt, loff_t *ppos)
4560 * There is no need to read what the user has written, this function
4561 * is just to make sure that there is no error when "echo" is used
4570 tracing_free_buffer_release(struct inode *inode, struct file *filp)
4572 struct trace_array *tr = inode->i_private;
4574 /* disable tracing ? */
4575 if (trace_flags & TRACE_ITER_STOP_ON_FREE)
4576 tracer_tracing_off(tr);
4577 /* resize the ring buffer to 0 */
4578 tracing_resize_ring_buffer(tr, 0, RING_BUFFER_ALL_CPUS);
4580 trace_array_put(tr);
4586 tracing_mark_write(struct file *filp, const char __user *ubuf,
4587 size_t cnt, loff_t *fpos)
4589 unsigned long addr = (unsigned long)ubuf;
4590 struct trace_array *tr = filp->private_data;
4591 struct ring_buffer_event *event;
4592 struct ring_buffer *buffer;
4593 struct print_entry *entry;
4594 unsigned long irq_flags;
4595 struct page *pages[2];
4605 if (tracing_disabled)
4608 if (!(trace_flags & TRACE_ITER_MARKERS))
4611 if (cnt > TRACE_BUF_SIZE)
4612 cnt = TRACE_BUF_SIZE;
4615 * Userspace is injecting traces into the kernel trace buffer.
4616 * We want to be as non intrusive as possible.
4617 * To do so, we do not want to allocate any special buffers
4618 * or take any locks, but instead write the userspace data
4619 * straight into the ring buffer.
4621 * First we need to pin the userspace buffer into memory,
4622 * which, most likely it is, because it just referenced it.
4623 * But there's no guarantee that it is. By using get_user_pages_fast()
4624 * and kmap_atomic/kunmap_atomic() we can get access to the
4625 * pages directly. We then write the data directly into the
4628 BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
4630 /* check if we cross pages */
4631 if ((addr & PAGE_MASK) != ((addr + cnt) & PAGE_MASK))
4634 offset = addr & (PAGE_SIZE - 1);
4637 ret = get_user_pages_fast(addr, nr_pages, 0, pages);
4638 if (ret < nr_pages) {
4640 put_page(pages[ret]);
4645 for (i = 0; i < nr_pages; i++)
4646 map_page[i] = kmap_atomic(pages[i]);
4648 local_save_flags(irq_flags);
4649 size = sizeof(*entry) + cnt + 2; /* possible \n added */
4650 buffer = tr->trace_buffer.buffer;
4651 event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
4652 irq_flags, preempt_count());
4654 /* Ring buffer disabled, return as if not open for write */
4659 entry = ring_buffer_event_data(event);
4660 entry->ip = _THIS_IP_;
4662 if (nr_pages == 2) {
4663 len = PAGE_SIZE - offset;
4664 memcpy(&entry->buf, map_page[0] + offset, len);
4665 memcpy(&entry->buf[len], map_page[1], cnt - len);
4667 memcpy(&entry->buf, map_page[0] + offset, cnt);
4669 if (entry->buf[cnt - 1] != '\n') {
4670 entry->buf[cnt] = '\n';
4671 entry->buf[cnt + 1] = '\0';
4673 entry->buf[cnt] = '\0';
4675 __buffer_unlock_commit(buffer, event);
4682 for (i = 0; i < nr_pages; i++){
4683 kunmap_atomic(map_page[i]);
4690 static int tracing_clock_show(struct seq_file *m, void *v)
4692 struct trace_array *tr = m->private;
4695 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++)
4697 "%s%s%s%s", i ? " " : "",
4698 i == tr->clock_id ? "[" : "", trace_clocks[i].name,
4699 i == tr->clock_id ? "]" : "");
4705 static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf,
4706 size_t cnt, loff_t *fpos)
4708 struct seq_file *m = filp->private_data;
4709 struct trace_array *tr = m->private;
4711 const char *clockstr;
4714 if (cnt >= sizeof(buf))
4717 if (copy_from_user(&buf, ubuf, cnt))
4722 clockstr = strstrip(buf);
4724 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) {
4725 if (strcmp(trace_clocks[i].name, clockstr) == 0)
4728 if (i == ARRAY_SIZE(trace_clocks))
4731 mutex_lock(&trace_types_lock);
4735 ring_buffer_set_clock(tr->trace_buffer.buffer, trace_clocks[i].func);
4738 * New clock may not be consistent with the previous clock.
4739 * Reset the buffer so that it doesn't have incomparable timestamps.
4741 tracing_reset_online_cpus(&tr->trace_buffer);
4743 #ifdef CONFIG_TRACER_MAX_TRACE
4744 if (tr->flags & TRACE_ARRAY_FL_GLOBAL && tr->max_buffer.buffer)
4745 ring_buffer_set_clock(tr->max_buffer.buffer, trace_clocks[i].func);
4746 tracing_reset_online_cpus(&tr->max_buffer);
4749 mutex_unlock(&trace_types_lock);
4756 static int tracing_clock_open(struct inode *inode, struct file *file)
4758 struct trace_array *tr = inode->i_private;
4761 if (tracing_disabled)
4764 if (trace_array_get(tr))
4767 ret = single_open(file, tracing_clock_show, inode->i_private);
4769 trace_array_put(tr);
4774 struct ftrace_buffer_info {
4775 struct trace_iterator iter;
4780 #ifdef CONFIG_TRACER_SNAPSHOT
4781 static int tracing_snapshot_open(struct inode *inode, struct file *file)
4783 struct trace_array *tr = inode->i_private;
4784 struct trace_iterator *iter;
4788 if (trace_array_get(tr) < 0)
4791 if (file->f_mode & FMODE_READ) {
4792 iter = __tracing_open(inode, file, true);
4794 ret = PTR_ERR(iter);
4796 /* Writes still need the seq_file to hold the private data */
4798 m = kzalloc(sizeof(*m), GFP_KERNEL);
4801 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
4809 iter->trace_buffer = &tr->max_buffer;
4810 iter->cpu_file = tracing_get_cpu(inode);
4812 file->private_data = m;
4816 trace_array_put(tr);
4822 tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
4825 struct seq_file *m = filp->private_data;
4826 struct trace_iterator *iter = m->private;
4827 struct trace_array *tr = iter->tr;
4831 ret = tracing_update_buffers();
4835 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
4839 mutex_lock(&trace_types_lock);
4841 if (tr->current_trace->use_max_tr) {
4848 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
4852 if (tr->allocated_snapshot)
4856 /* Only allow per-cpu swap if the ring buffer supports it */
4857 #ifndef CONFIG_RING_BUFFER_ALLOW_SWAP
4858 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
4863 if (!tr->allocated_snapshot) {
4864 ret = alloc_snapshot(tr);
4868 local_irq_disable();
4869 /* Now, we're going to swap */
4870 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
4871 update_max_tr(tr, current, smp_processor_id());
4873 update_max_tr_single(tr, current, iter->cpu_file);
4877 if (tr->allocated_snapshot) {
4878 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
4879 tracing_reset_online_cpus(&tr->max_buffer);
4881 tracing_reset(&tr->max_buffer, iter->cpu_file);
4891 mutex_unlock(&trace_types_lock);
4895 static int tracing_snapshot_release(struct inode *inode, struct file *file)
4897 struct seq_file *m = file->private_data;
4900 ret = tracing_release(inode, file);
4902 if (file->f_mode & FMODE_READ)
4905 /* If write only, the seq_file is just a stub */
4913 static int tracing_buffers_open(struct inode *inode, struct file *filp);
4914 static ssize_t tracing_buffers_read(struct file *filp, char __user *ubuf,
4915 size_t count, loff_t *ppos);
4916 static int tracing_buffers_release(struct inode *inode, struct file *file);
4917 static ssize_t tracing_buffers_splice_read(struct file *file, loff_t *ppos,
4918 struct pipe_inode_info *pipe, size_t len, unsigned int flags);
4920 static int snapshot_raw_open(struct inode *inode, struct file *filp)
4922 struct ftrace_buffer_info *info;
4925 ret = tracing_buffers_open(inode, filp);
4929 info = filp->private_data;
4931 if (info->iter.trace->use_max_tr) {
4932 tracing_buffers_release(inode, filp);
4936 info->iter.snapshot = true;
4937 info->iter.trace_buffer = &info->iter.tr->max_buffer;
4942 #endif /* CONFIG_TRACER_SNAPSHOT */
4945 static const struct file_operations tracing_max_lat_fops = {
4946 .open = tracing_open_generic,
4947 .read = tracing_max_lat_read,
4948 .write = tracing_max_lat_write,
4949 .llseek = generic_file_llseek,
4952 static const struct file_operations set_tracer_fops = {
4953 .open = tracing_open_generic,
4954 .read = tracing_set_trace_read,
4955 .write = tracing_set_trace_write,
4956 .llseek = generic_file_llseek,
4959 static const struct file_operations tracing_pipe_fops = {
4960 .open = tracing_open_pipe,
4961 .poll = tracing_poll_pipe,
4962 .read = tracing_read_pipe,
4963 .splice_read = tracing_splice_read_pipe,
4964 .release = tracing_release_pipe,
4965 .llseek = no_llseek,
4968 static const struct file_operations tracing_entries_fops = {
4969 .open = tracing_open_generic_tr,
4970 .read = tracing_entries_read,
4971 .write = tracing_entries_write,
4972 .llseek = generic_file_llseek,
4973 .release = tracing_release_generic_tr,
4976 static const struct file_operations tracing_total_entries_fops = {
4977 .open = tracing_open_generic_tr,
4978 .read = tracing_total_entries_read,
4979 .llseek = generic_file_llseek,
4980 .release = tracing_release_generic_tr,
4983 static const struct file_operations tracing_free_buffer_fops = {
4984 .open = tracing_open_generic_tr,
4985 .write = tracing_free_buffer_write,
4986 .release = tracing_free_buffer_release,
4989 static const struct file_operations tracing_mark_fops = {
4990 .open = tracing_open_generic_tr,
4991 .write = tracing_mark_write,
4992 .llseek = generic_file_llseek,
4993 .release = tracing_release_generic_tr,
4996 static const struct file_operations trace_clock_fops = {
4997 .open = tracing_clock_open,
4999 .llseek = seq_lseek,
5000 .release = tracing_single_release_tr,
5001 .write = tracing_clock_write,
5004 #ifdef CONFIG_TRACER_SNAPSHOT
5005 static const struct file_operations snapshot_fops = {
5006 .open = tracing_snapshot_open,
5008 .write = tracing_snapshot_write,
5009 .llseek = tracing_seek,
5010 .release = tracing_snapshot_release,
5013 static const struct file_operations snapshot_raw_fops = {
5014 .open = snapshot_raw_open,
5015 .read = tracing_buffers_read,
5016 .release = tracing_buffers_release,
5017 .splice_read = tracing_buffers_splice_read,
5018 .llseek = no_llseek,
5021 #endif /* CONFIG_TRACER_SNAPSHOT */
5023 static int tracing_buffers_open(struct inode *inode, struct file *filp)
5025 struct trace_array *tr = inode->i_private;
5026 struct ftrace_buffer_info *info;
5029 if (tracing_disabled)
5032 if (trace_array_get(tr) < 0)
5035 info = kzalloc(sizeof(*info), GFP_KERNEL);
5037 trace_array_put(tr);
5041 mutex_lock(&trace_types_lock);
5044 info->iter.cpu_file = tracing_get_cpu(inode);
5045 info->iter.trace = tr->current_trace;
5046 info->iter.trace_buffer = &tr->trace_buffer;
5048 /* Force reading ring buffer for first read */
5049 info->read = (unsigned int)-1;
5051 filp->private_data = info;
5053 mutex_unlock(&trace_types_lock);
5055 ret = nonseekable_open(inode, filp);
5057 trace_array_put(tr);
5063 tracing_buffers_poll(struct file *filp, poll_table *poll_table)
5065 struct ftrace_buffer_info *info = filp->private_data;
5066 struct trace_iterator *iter = &info->iter;
5068 return trace_poll(iter, filp, poll_table);
5072 tracing_buffers_read(struct file *filp, char __user *ubuf,
5073 size_t count, loff_t *ppos)
5075 struct ftrace_buffer_info *info = filp->private_data;
5076 struct trace_iterator *iter = &info->iter;
5083 mutex_lock(&trace_types_lock);
5085 #ifdef CONFIG_TRACER_MAX_TRACE
5086 if (iter->snapshot && iter->tr->current_trace->use_max_tr) {
5093 info->spare = ring_buffer_alloc_read_page(iter->trace_buffer->buffer,
5099 /* Do we have previous read data to read? */
5100 if (info->read < PAGE_SIZE)
5104 trace_access_lock(iter->cpu_file);
5105 ret = ring_buffer_read_page(iter->trace_buffer->buffer,
5109 trace_access_unlock(iter->cpu_file);
5112 if (trace_empty(iter)) {
5113 if ((filp->f_flags & O_NONBLOCK)) {
5117 mutex_unlock(&trace_types_lock);
5118 ret = iter->trace->wait_pipe(iter);
5119 mutex_lock(&trace_types_lock);
5124 if (signal_pending(current)) {
5136 size = PAGE_SIZE - info->read;
5140 ret = copy_to_user(ubuf, info->spare + info->read, size);
5151 mutex_unlock(&trace_types_lock);
5156 static int tracing_buffers_release(struct inode *inode, struct file *file)
5158 struct ftrace_buffer_info *info = file->private_data;
5159 struct trace_iterator *iter = &info->iter;
5161 mutex_lock(&trace_types_lock);
5163 __trace_array_put(iter->tr);
5166 ring_buffer_free_read_page(iter->trace_buffer->buffer, info->spare);
5169 mutex_unlock(&trace_types_lock);
5175 struct ring_buffer *buffer;
5180 static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
5181 struct pipe_buffer *buf)
5183 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
5188 ring_buffer_free_read_page(ref->buffer, ref->page);
5193 static void buffer_pipe_buf_get(struct pipe_inode_info *pipe,
5194 struct pipe_buffer *buf)
5196 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
5201 /* Pipe buffer operations for a buffer. */
5202 static const struct pipe_buf_operations buffer_pipe_buf_ops = {
5204 .map = generic_pipe_buf_map,
5205 .unmap = generic_pipe_buf_unmap,
5206 .confirm = generic_pipe_buf_confirm,
5207 .release = buffer_pipe_buf_release,
5208 .steal = generic_pipe_buf_steal,
5209 .get = buffer_pipe_buf_get,
5213 * Callback from splice_to_pipe(), if we need to release some pages
5214 * at the end of the spd in case we error'ed out in filling the pipe.
5216 static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
5218 struct buffer_ref *ref =
5219 (struct buffer_ref *)spd->partial[i].private;
5224 ring_buffer_free_read_page(ref->buffer, ref->page);
5226 spd->partial[i].private = 0;
5230 tracing_buffers_splice_read(struct file *file, loff_t *ppos,
5231 struct pipe_inode_info *pipe, size_t len,
5234 struct ftrace_buffer_info *info = file->private_data;
5235 struct trace_iterator *iter = &info->iter;
5236 struct partial_page partial_def[PIPE_DEF_BUFFERS];
5237 struct page *pages_def[PIPE_DEF_BUFFERS];
5238 struct splice_pipe_desc spd = {
5240 .partial = partial_def,
5241 .nr_pages_max = PIPE_DEF_BUFFERS,
5243 .ops = &buffer_pipe_buf_ops,
5244 .spd_release = buffer_spd_release,
5246 struct buffer_ref *ref;
5247 int entries, size, i;
5250 mutex_lock(&trace_types_lock);
5252 #ifdef CONFIG_TRACER_MAX_TRACE
5253 if (iter->snapshot && iter->tr->current_trace->use_max_tr) {
5259 if (splice_grow_spd(pipe, &spd)) {
5264 if (*ppos & (PAGE_SIZE - 1)) {
5269 if (len & (PAGE_SIZE - 1)) {
5270 if (len < PAGE_SIZE) {
5278 trace_access_lock(iter->cpu_file);
5279 entries = ring_buffer_entries_cpu(iter->trace_buffer->buffer, iter->cpu_file);
5281 for (i = 0; i < pipe->buffers && len && entries; i++, len -= PAGE_SIZE) {
5285 ref = kzalloc(sizeof(*ref), GFP_KERNEL);
5290 ref->buffer = iter->trace_buffer->buffer;
5291 ref->page = ring_buffer_alloc_read_page(ref->buffer, iter->cpu_file);
5297 r = ring_buffer_read_page(ref->buffer, &ref->page,
5298 len, iter->cpu_file, 1);
5300 ring_buffer_free_read_page(ref->buffer, ref->page);
5306 * zero out any left over data, this is going to
5309 size = ring_buffer_page_len(ref->page);
5310 if (size < PAGE_SIZE)
5311 memset(ref->page + size, 0, PAGE_SIZE - size);
5313 page = virt_to_page(ref->page);
5315 spd.pages[i] = page;
5316 spd.partial[i].len = PAGE_SIZE;
5317 spd.partial[i].offset = 0;
5318 spd.partial[i].private = (unsigned long)ref;
5322 entries = ring_buffer_entries_cpu(iter->trace_buffer->buffer, iter->cpu_file);
5325 trace_access_unlock(iter->cpu_file);
5328 /* did we read anything? */
5329 if (!spd.nr_pages) {
5330 if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK)) {
5334 mutex_unlock(&trace_types_lock);
5335 ret = iter->trace->wait_pipe(iter);
5336 mutex_lock(&trace_types_lock);
5339 if (signal_pending(current)) {
5346 ret = splice_to_pipe(pipe, &spd);
5347 splice_shrink_spd(&spd);
5349 mutex_unlock(&trace_types_lock);
5354 static const struct file_operations tracing_buffers_fops = {
5355 .open = tracing_buffers_open,
5356 .read = tracing_buffers_read,
5357 .poll = tracing_buffers_poll,
5358 .release = tracing_buffers_release,
5359 .splice_read = tracing_buffers_splice_read,
5360 .llseek = no_llseek,
5364 tracing_stats_read(struct file *filp, char __user *ubuf,
5365 size_t count, loff_t *ppos)
5367 struct inode *inode = file_inode(filp);
5368 struct trace_array *tr = inode->i_private;
5369 struct trace_buffer *trace_buf = &tr->trace_buffer;
5370 int cpu = tracing_get_cpu(inode);
5371 struct trace_seq *s;
5373 unsigned long long t;
5374 unsigned long usec_rem;
5376 s = kmalloc(sizeof(*s), GFP_KERNEL);
5382 cnt = ring_buffer_entries_cpu(trace_buf->buffer, cpu);
5383 trace_seq_printf(s, "entries: %ld\n", cnt);
5385 cnt = ring_buffer_overrun_cpu(trace_buf->buffer, cpu);
5386 trace_seq_printf(s, "overrun: %ld\n", cnt);
5388 cnt = ring_buffer_commit_overrun_cpu(trace_buf->buffer, cpu);
5389 trace_seq_printf(s, "commit overrun: %ld\n", cnt);
5391 cnt = ring_buffer_bytes_cpu(trace_buf->buffer, cpu);
5392 trace_seq_printf(s, "bytes: %ld\n", cnt);
5394 if (trace_clocks[tr->clock_id].in_ns) {
5395 /* local or global for trace_clock */
5396 t = ns2usecs(ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
5397 usec_rem = do_div(t, USEC_PER_SEC);
5398 trace_seq_printf(s, "oldest event ts: %5llu.%06lu\n",
5401 t = ns2usecs(ring_buffer_time_stamp(trace_buf->buffer, cpu));
5402 usec_rem = do_div(t, USEC_PER_SEC);
5403 trace_seq_printf(s, "now ts: %5llu.%06lu\n", t, usec_rem);
5405 /* counter or tsc mode for trace_clock */
5406 trace_seq_printf(s, "oldest event ts: %llu\n",
5407 ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
5409 trace_seq_printf(s, "now ts: %llu\n",
5410 ring_buffer_time_stamp(trace_buf->buffer, cpu));
5413 cnt = ring_buffer_dropped_events_cpu(trace_buf->buffer, cpu);
5414 trace_seq_printf(s, "dropped events: %ld\n", cnt);
5416 cnt = ring_buffer_read_events_cpu(trace_buf->buffer, cpu);
5417 trace_seq_printf(s, "read events: %ld\n", cnt);
5419 count = simple_read_from_buffer(ubuf, count, ppos, s->buffer, s->len);
5426 static const struct file_operations tracing_stats_fops = {
5427 .open = tracing_open_generic_tr,
5428 .read = tracing_stats_read,
5429 .llseek = generic_file_llseek,
5430 .release = tracing_release_generic_tr,
5433 #ifdef CONFIG_DYNAMIC_FTRACE
5435 int __weak ftrace_arch_read_dyn_info(char *buf, int size)
5441 tracing_read_dyn_info(struct file *filp, char __user *ubuf,
5442 size_t cnt, loff_t *ppos)
5444 static char ftrace_dyn_info_buffer[1024];
5445 static DEFINE_MUTEX(dyn_info_mutex);
5446 unsigned long *p = filp->private_data;
5447 char *buf = ftrace_dyn_info_buffer;
5448 int size = ARRAY_SIZE(ftrace_dyn_info_buffer);
5451 mutex_lock(&dyn_info_mutex);
5452 r = sprintf(buf, "%ld ", *p);
5454 r += ftrace_arch_read_dyn_info(buf+r, (size-1)-r);
5457 r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
5459 mutex_unlock(&dyn_info_mutex);
5464 static const struct file_operations tracing_dyn_info_fops = {
5465 .open = tracing_open_generic,
5466 .read = tracing_read_dyn_info,
5467 .llseek = generic_file_llseek,
5469 #endif /* CONFIG_DYNAMIC_FTRACE */
5471 #if defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE)
5473 ftrace_snapshot(unsigned long ip, unsigned long parent_ip, void **data)
5479 ftrace_count_snapshot(unsigned long ip, unsigned long parent_ip, void **data)
5481 unsigned long *count = (long *)data;
5493 ftrace_snapshot_print(struct seq_file *m, unsigned long ip,
5494 struct ftrace_probe_ops *ops, void *data)
5496 long count = (long)data;
5498 seq_printf(m, "%ps:", (void *)ip);
5500 seq_printf(m, "snapshot");
5503 seq_printf(m, ":unlimited\n");
5505 seq_printf(m, ":count=%ld\n", count);
5510 static struct ftrace_probe_ops snapshot_probe_ops = {
5511 .func = ftrace_snapshot,
5512 .print = ftrace_snapshot_print,
5515 static struct ftrace_probe_ops snapshot_count_probe_ops = {
5516 .func = ftrace_count_snapshot,
5517 .print = ftrace_snapshot_print,
5521 ftrace_trace_snapshot_callback(struct ftrace_hash *hash,
5522 char *glob, char *cmd, char *param, int enable)
5524 struct ftrace_probe_ops *ops;
5525 void *count = (void *)-1;
5529 /* hash funcs only work with set_ftrace_filter */
5533 ops = param ? &snapshot_count_probe_ops : &snapshot_probe_ops;
5535 if (glob[0] == '!') {
5536 unregister_ftrace_function_probe_func(glob+1, ops);
5543 number = strsep(¶m, ":");
5545 if (!strlen(number))
5549 * We use the callback data field (which is a pointer)
5552 ret = kstrtoul(number, 0, (unsigned long *)&count);
5557 ret = register_ftrace_function_probe(glob, ops, count);
5560 alloc_snapshot(&global_trace);
5562 return ret < 0 ? ret : 0;
5565 static struct ftrace_func_command ftrace_snapshot_cmd = {
5567 .func = ftrace_trace_snapshot_callback,
5570 static int register_snapshot_cmd(void)
5572 return register_ftrace_command(&ftrace_snapshot_cmd);
5575 static inline int register_snapshot_cmd(void) { return 0; }
5576 #endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
5578 struct dentry *tracing_init_dentry_tr(struct trace_array *tr)
5583 if (!debugfs_initialized())
5586 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
5587 tr->dir = debugfs_create_dir("tracing", NULL);
5590 pr_warn_once("Could not create debugfs directory 'tracing'\n");
5595 struct dentry *tracing_init_dentry(void)
5597 return tracing_init_dentry_tr(&global_trace);
5600 static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu)
5602 struct dentry *d_tracer;
5605 return tr->percpu_dir;
5607 d_tracer = tracing_init_dentry_tr(tr);
5611 tr->percpu_dir = debugfs_create_dir("per_cpu", d_tracer);
5613 WARN_ONCE(!tr->percpu_dir,
5614 "Could not create debugfs directory 'per_cpu/%d'\n", cpu);
5616 return tr->percpu_dir;
5619 static struct dentry *
5620 trace_create_cpu_file(const char *name, umode_t mode, struct dentry *parent,
5621 void *data, long cpu, const struct file_operations *fops)
5623 struct dentry *ret = trace_create_file(name, mode, parent, data, fops);
5625 if (ret) /* See tracing_get_cpu() */
5626 ret->d_inode->i_cdev = (void *)(cpu + 1);
5631 tracing_init_debugfs_percpu(struct trace_array *tr, long cpu)
5633 struct dentry *d_percpu = tracing_dentry_percpu(tr, cpu);
5634 struct dentry *d_cpu;
5635 char cpu_dir[30]; /* 30 characters should be more than enough */
5640 snprintf(cpu_dir, 30, "cpu%ld", cpu);
5641 d_cpu = debugfs_create_dir(cpu_dir, d_percpu);
5643 pr_warning("Could not create debugfs '%s' entry\n", cpu_dir);
5647 /* per cpu trace_pipe */
5648 trace_create_cpu_file("trace_pipe", 0444, d_cpu,
5649 tr, cpu, &tracing_pipe_fops);
5652 trace_create_cpu_file("trace", 0644, d_cpu,
5653 tr, cpu, &tracing_fops);
5655 trace_create_cpu_file("trace_pipe_raw", 0444, d_cpu,
5656 tr, cpu, &tracing_buffers_fops);
5658 trace_create_cpu_file("stats", 0444, d_cpu,
5659 tr, cpu, &tracing_stats_fops);
5661 trace_create_cpu_file("buffer_size_kb", 0444, d_cpu,
5662 tr, cpu, &tracing_entries_fops);
5664 #ifdef CONFIG_TRACER_SNAPSHOT
5665 trace_create_cpu_file("snapshot", 0644, d_cpu,
5666 tr, cpu, &snapshot_fops);
5668 trace_create_cpu_file("snapshot_raw", 0444, d_cpu,
5669 tr, cpu, &snapshot_raw_fops);
5673 #ifdef CONFIG_FTRACE_SELFTEST
5674 /* Let selftest have access to static functions in this file */
5675 #include "trace_selftest.c"
5678 struct trace_option_dentry {
5679 struct tracer_opt *opt;
5680 struct tracer_flags *flags;
5681 struct trace_array *tr;
5682 struct dentry *entry;
5686 trace_options_read(struct file *filp, char __user *ubuf, size_t cnt,
5689 struct trace_option_dentry *topt = filp->private_data;
5692 if (topt->flags->val & topt->opt->bit)
5697 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
5701 trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt,
5704 struct trace_option_dentry *topt = filp->private_data;
5708 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
5712 if (val != 0 && val != 1)
5715 if (!!(topt->flags->val & topt->opt->bit) != val) {
5716 mutex_lock(&trace_types_lock);
5717 ret = __set_tracer_option(topt->tr->current_trace, topt->flags,
5719 mutex_unlock(&trace_types_lock);
5730 static const struct file_operations trace_options_fops = {
5731 .open = tracing_open_generic,
5732 .read = trace_options_read,
5733 .write = trace_options_write,
5734 .llseek = generic_file_llseek,
5738 trace_options_core_read(struct file *filp, char __user *ubuf, size_t cnt,
5741 long index = (long)filp->private_data;
5744 if (trace_flags & (1 << index))
5749 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
5753 trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
5756 struct trace_array *tr = &global_trace;
5757 long index = (long)filp->private_data;
5761 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
5765 if (val != 0 && val != 1)
5768 mutex_lock(&trace_types_lock);
5769 ret = set_tracer_flag(tr, 1 << index, val);
5770 mutex_unlock(&trace_types_lock);
5780 static const struct file_operations trace_options_core_fops = {
5781 .open = tracing_open_generic,
5782 .read = trace_options_core_read,
5783 .write = trace_options_core_write,
5784 .llseek = generic_file_llseek,
5787 struct dentry *trace_create_file(const char *name,
5789 struct dentry *parent,
5791 const struct file_operations *fops)
5795 ret = debugfs_create_file(name, mode, parent, data, fops);
5797 pr_warning("Could not create debugfs '%s' entry\n", name);
5803 static struct dentry *trace_options_init_dentry(struct trace_array *tr)
5805 struct dentry *d_tracer;
5810 d_tracer = tracing_init_dentry_tr(tr);
5814 tr->options = debugfs_create_dir("options", d_tracer);
5816 pr_warning("Could not create debugfs directory 'options'\n");
5824 create_trace_option_file(struct trace_array *tr,
5825 struct trace_option_dentry *topt,
5826 struct tracer_flags *flags,
5827 struct tracer_opt *opt)
5829 struct dentry *t_options;
5831 t_options = trace_options_init_dentry(tr);
5835 topt->flags = flags;
5839 topt->entry = trace_create_file(opt->name, 0644, t_options, topt,
5840 &trace_options_fops);
5844 static struct trace_option_dentry *
5845 create_trace_option_files(struct trace_array *tr, struct tracer *tracer)
5847 struct trace_option_dentry *topts;
5848 struct tracer_flags *flags;
5849 struct tracer_opt *opts;
5855 flags = tracer->flags;
5857 if (!flags || !flags->opts)
5862 for (cnt = 0; opts[cnt].name; cnt++)
5865 topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL);
5869 for (cnt = 0; opts[cnt].name; cnt++)
5870 create_trace_option_file(tr, &topts[cnt], flags,
5877 destroy_trace_option_files(struct trace_option_dentry *topts)
5884 for (cnt = 0; topts[cnt].opt; cnt++) {
5885 if (topts[cnt].entry)
5886 debugfs_remove(topts[cnt].entry);
5892 static struct dentry *
5893 create_trace_option_core_file(struct trace_array *tr,
5894 const char *option, long index)
5896 struct dentry *t_options;
5898 t_options = trace_options_init_dentry(tr);
5902 return trace_create_file(option, 0644, t_options, (void *)index,
5903 &trace_options_core_fops);
5906 static __init void create_trace_options_dir(struct trace_array *tr)
5908 struct dentry *t_options;
5911 t_options = trace_options_init_dentry(tr);
5915 for (i = 0; trace_options[i]; i++)
5916 create_trace_option_core_file(tr, trace_options[i], i);
5920 rb_simple_read(struct file *filp, char __user *ubuf,
5921 size_t cnt, loff_t *ppos)
5923 struct trace_array *tr = filp->private_data;
5927 r = tracer_tracing_is_on(tr);
5928 r = sprintf(buf, "%d\n", r);
5930 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
5934 rb_simple_write(struct file *filp, const char __user *ubuf,
5935 size_t cnt, loff_t *ppos)
5937 struct trace_array *tr = filp->private_data;
5938 struct ring_buffer *buffer = tr->trace_buffer.buffer;
5942 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
5947 mutex_lock(&trace_types_lock);
5949 tracer_tracing_on(tr);
5950 if (tr->current_trace->start)
5951 tr->current_trace->start(tr);
5953 tracer_tracing_off(tr);
5954 if (tr->current_trace->stop)
5955 tr->current_trace->stop(tr);
5957 mutex_unlock(&trace_types_lock);
5965 static const struct file_operations rb_simple_fops = {
5966 .open = tracing_open_generic_tr,
5967 .read = rb_simple_read,
5968 .write = rb_simple_write,
5969 .release = tracing_release_generic_tr,
5970 .llseek = default_llseek,
5973 struct dentry *trace_instance_dir;
5976 init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer);
5978 static void init_trace_buffers(struct trace_array *tr, struct trace_buffer *buf)
5982 for_each_tracing_cpu(cpu) {
5983 memset(per_cpu_ptr(buf->data, cpu), 0, sizeof(struct trace_array_cpu));
5984 per_cpu_ptr(buf->data, cpu)->trace_cpu.cpu = cpu;
5985 per_cpu_ptr(buf->data, cpu)->trace_cpu.tr = tr;
5990 allocate_trace_buffer(struct trace_array *tr, struct trace_buffer *buf, int size)
5992 enum ring_buffer_flags rb_flags;
5994 rb_flags = trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0;
5998 buf->buffer = ring_buffer_alloc(size, rb_flags);
6002 buf->data = alloc_percpu(struct trace_array_cpu);
6004 ring_buffer_free(buf->buffer);
6008 init_trace_buffers(tr, buf);
6010 /* Allocate the first page for all buffers */
6011 set_buffer_entries(&tr->trace_buffer,
6012 ring_buffer_size(tr->trace_buffer.buffer, 0));
6017 static int allocate_trace_buffers(struct trace_array *tr, int size)
6021 ret = allocate_trace_buffer(tr, &tr->trace_buffer, size);
6025 #ifdef CONFIG_TRACER_MAX_TRACE
6026 ret = allocate_trace_buffer(tr, &tr->max_buffer,
6027 allocate_snapshot ? size : 1);
6029 ring_buffer_free(tr->trace_buffer.buffer);
6030 free_percpu(tr->trace_buffer.data);
6033 tr->allocated_snapshot = allocate_snapshot;
6036 * Only the top level trace array gets its snapshot allocated
6037 * from the kernel command line.
6039 allocate_snapshot = false;
6044 static int new_instance_create(const char *name)
6046 struct trace_array *tr;
6049 mutex_lock(&trace_types_lock);
6052 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6053 if (tr->name && strcmp(tr->name, name) == 0)
6058 tr = kzalloc(sizeof(*tr), GFP_KERNEL);
6062 tr->name = kstrdup(name, GFP_KERNEL);
6066 raw_spin_lock_init(&tr->start_lock);
6068 tr->current_trace = &nop_trace;
6070 INIT_LIST_HEAD(&tr->systems);
6071 INIT_LIST_HEAD(&tr->events);
6073 if (allocate_trace_buffers(tr, trace_buf_size) < 0)
6076 /* Holder for file callbacks */
6077 tr->trace_cpu.cpu = RING_BUFFER_ALL_CPUS;
6078 tr->trace_cpu.tr = tr;
6080 tr->dir = debugfs_create_dir(name, trace_instance_dir);
6084 ret = event_trace_add_tracer(tr->dir, tr);
6086 debugfs_remove_recursive(tr->dir);
6090 init_tracer_debugfs(tr, tr->dir);
6092 list_add(&tr->list, &ftrace_trace_arrays);
6094 mutex_unlock(&trace_types_lock);
6099 if (tr->trace_buffer.buffer)
6100 ring_buffer_free(tr->trace_buffer.buffer);
6105 mutex_unlock(&trace_types_lock);
6111 static int instance_delete(const char *name)
6113 struct trace_array *tr;
6117 mutex_lock(&trace_types_lock);
6120 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6121 if (tr->name && strcmp(tr->name, name) == 0) {
6133 list_del(&tr->list);
6135 event_trace_del_tracer(tr);
6136 debugfs_remove_recursive(tr->dir);
6137 free_percpu(tr->trace_buffer.data);
6138 ring_buffer_free(tr->trace_buffer.buffer);
6146 mutex_unlock(&trace_types_lock);
6151 static int instance_mkdir (struct inode *inode, struct dentry *dentry, umode_t mode)
6153 struct dentry *parent;
6156 /* Paranoid: Make sure the parent is the "instances" directory */
6157 parent = hlist_entry(inode->i_dentry.first, struct dentry, d_alias);
6158 if (WARN_ON_ONCE(parent != trace_instance_dir))
6162 * The inode mutex is locked, but debugfs_create_dir() will also
6163 * take the mutex. As the instances directory can not be destroyed
6164 * or changed in any other way, it is safe to unlock it, and
6165 * let the dentry try. If two users try to make the same dir at
6166 * the same time, then the new_instance_create() will determine the
6169 mutex_unlock(&inode->i_mutex);
6171 ret = new_instance_create(dentry->d_iname);
6173 mutex_lock(&inode->i_mutex);
6178 static int instance_rmdir(struct inode *inode, struct dentry *dentry)
6180 struct dentry *parent;
6183 /* Paranoid: Make sure the parent is the "instances" directory */
6184 parent = hlist_entry(inode->i_dentry.first, struct dentry, d_alias);
6185 if (WARN_ON_ONCE(parent != trace_instance_dir))
6188 /* The caller did a dget() on dentry */
6189 mutex_unlock(&dentry->d_inode->i_mutex);
6192 * The inode mutex is locked, but debugfs_create_dir() will also
6193 * take the mutex. As the instances directory can not be destroyed
6194 * or changed in any other way, it is safe to unlock it, and
6195 * let the dentry try. If two users try to make the same dir at
6196 * the same time, then the instance_delete() will determine the
6199 mutex_unlock(&inode->i_mutex);
6201 ret = instance_delete(dentry->d_iname);
6203 mutex_lock_nested(&inode->i_mutex, I_MUTEX_PARENT);
6204 mutex_lock(&dentry->d_inode->i_mutex);
6209 static const struct inode_operations instance_dir_inode_operations = {
6210 .lookup = simple_lookup,
6211 .mkdir = instance_mkdir,
6212 .rmdir = instance_rmdir,
6215 static __init void create_trace_instances(struct dentry *d_tracer)
6217 trace_instance_dir = debugfs_create_dir("instances", d_tracer);
6218 if (WARN_ON(!trace_instance_dir))
6221 /* Hijack the dir inode operations, to allow mkdir */
6222 trace_instance_dir->d_inode->i_op = &instance_dir_inode_operations;
6226 init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer)
6230 trace_create_file("trace_options", 0644, d_tracer,
6231 tr, &tracing_iter_fops);
6233 trace_create_file("trace", 0644, d_tracer,
6236 trace_create_file("trace_pipe", 0444, d_tracer,
6237 tr, &tracing_pipe_fops);
6239 trace_create_file("buffer_size_kb", 0644, d_tracer,
6240 tr, &tracing_entries_fops);
6242 trace_create_file("buffer_total_size_kb", 0444, d_tracer,
6243 tr, &tracing_total_entries_fops);
6245 trace_create_file("free_buffer", 0644, d_tracer,
6246 tr, &tracing_free_buffer_fops);
6248 trace_create_file("trace_marker", 0220, d_tracer,
6249 tr, &tracing_mark_fops);
6251 trace_create_file("saved_tgids", 0444, d_tracer,
6252 tr, &tracing_saved_tgids_fops);
6254 trace_create_file("trace_clock", 0644, d_tracer, tr,
6257 trace_create_file("tracing_on", 0644, d_tracer,
6258 tr, &rb_simple_fops);
6260 #ifdef CONFIG_TRACER_SNAPSHOT
6261 trace_create_file("snapshot", 0644, d_tracer,
6262 tr, &snapshot_fops);
6265 for_each_tracing_cpu(cpu)
6266 tracing_init_debugfs_percpu(tr, cpu);
6270 static __init int tracer_init_debugfs(void)
6272 struct dentry *d_tracer;
6274 trace_access_lock_init();
6276 d_tracer = tracing_init_dentry();
6280 init_tracer_debugfs(&global_trace, d_tracer);
6282 trace_create_file("tracing_cpumask", 0644, d_tracer,
6283 &global_trace, &tracing_cpumask_fops);
6285 trace_create_file("available_tracers", 0444, d_tracer,
6286 &global_trace, &show_traces_fops);
6288 trace_create_file("current_tracer", 0644, d_tracer,
6289 &global_trace, &set_tracer_fops);
6291 #ifdef CONFIG_TRACER_MAX_TRACE
6292 trace_create_file("tracing_max_latency", 0644, d_tracer,
6293 &tracing_max_latency, &tracing_max_lat_fops);
6296 trace_create_file("tracing_thresh", 0644, d_tracer,
6297 &tracing_thresh, &tracing_max_lat_fops);
6299 trace_create_file("README", 0444, d_tracer,
6300 NULL, &tracing_readme_fops);
6302 trace_create_file("saved_cmdlines", 0444, d_tracer,
6303 NULL, &tracing_saved_cmdlines_fops);
6305 #ifdef CONFIG_DYNAMIC_FTRACE
6306 trace_create_file("dyn_ftrace_total_info", 0444, d_tracer,
6307 &ftrace_update_tot_cnt, &tracing_dyn_info_fops);
6310 create_trace_instances(d_tracer);
6312 create_trace_options_dir(&global_trace);
6317 static int trace_panic_handler(struct notifier_block *this,
6318 unsigned long event, void *unused)
6320 if (ftrace_dump_on_oops)
6321 ftrace_dump(ftrace_dump_on_oops);
6325 static struct notifier_block trace_panic_notifier = {
6326 .notifier_call = trace_panic_handler,
6328 .priority = 150 /* priority: INT_MAX >= x >= 0 */
6331 static int trace_die_handler(struct notifier_block *self,
6337 if (ftrace_dump_on_oops)
6338 ftrace_dump(ftrace_dump_on_oops);
6346 static struct notifier_block trace_die_notifier = {
6347 .notifier_call = trace_die_handler,
6352 * printk is set to max of 1024, we really don't need it that big.
6353 * Nothing should be printing 1000 characters anyway.
6355 #define TRACE_MAX_PRINT 1000
6358 * Define here KERN_TRACE so that we have one place to modify
6359 * it if we decide to change what log level the ftrace dump
6362 #define KERN_TRACE KERN_EMERG
6365 trace_printk_seq(struct trace_seq *s)
6367 /* Probably should print a warning here. */
6368 if (s->len >= TRACE_MAX_PRINT)
6369 s->len = TRACE_MAX_PRINT;
6371 /* should be zero ended, but we are paranoid. */
6372 s->buffer[s->len] = 0;
6374 printk(KERN_TRACE "%s", s->buffer);
6379 void trace_init_global_iter(struct trace_iterator *iter)
6381 iter->tr = &global_trace;
6382 iter->trace = iter->tr->current_trace;
6383 iter->cpu_file = RING_BUFFER_ALL_CPUS;
6384 iter->trace_buffer = &global_trace.trace_buffer;
6387 void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
6389 /* use static because iter can be a bit big for the stack */
6390 static struct trace_iterator iter;
6391 static atomic_t dump_running;
6392 unsigned int old_userobj;
6393 unsigned long flags;
6396 /* Only allow one dump user at a time. */
6397 if (atomic_inc_return(&dump_running) != 1) {
6398 atomic_dec(&dump_running);
6403 * Always turn off tracing when we dump.
6404 * We don't need to show trace output of what happens
6405 * between multiple crashes.
6407 * If the user does a sysrq-z, then they can re-enable
6408 * tracing with echo 1 > tracing_on.
6412 local_irq_save(flags);
6414 /* Simulate the iterator */
6415 trace_init_global_iter(&iter);
6417 for_each_tracing_cpu(cpu) {
6418 atomic_inc(&per_cpu_ptr(iter.tr->trace_buffer.data, cpu)->disabled);
6421 old_userobj = trace_flags & TRACE_ITER_SYM_USEROBJ;
6423 /* don't look at user memory in panic mode */
6424 trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
6426 switch (oops_dump_mode) {
6428 iter.cpu_file = RING_BUFFER_ALL_CPUS;
6431 iter.cpu_file = raw_smp_processor_id();
6436 printk(KERN_TRACE "Bad dumping mode, switching to all CPUs dump\n");
6437 iter.cpu_file = RING_BUFFER_ALL_CPUS;
6440 printk(KERN_TRACE "Dumping ftrace buffer:\n");
6442 /* Did function tracer already get disabled? */
6443 if (ftrace_is_dead()) {
6444 printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
6445 printk("# MAY BE MISSING FUNCTION EVENTS\n");
6449 * We need to stop all tracing on all CPUS to read the
6450 * the next buffer. This is a bit expensive, but is
6451 * not done often. We fill all what we can read,
6452 * and then release the locks again.
6455 while (!trace_empty(&iter)) {
6458 printk(KERN_TRACE "---------------------------------\n");
6462 /* reset all but tr, trace, and overruns */
6463 memset(&iter.seq, 0,
6464 sizeof(struct trace_iterator) -
6465 offsetof(struct trace_iterator, seq));
6466 iter.iter_flags |= TRACE_FILE_LAT_FMT;
6469 if (trace_find_next_entry_inc(&iter) != NULL) {
6472 ret = print_trace_line(&iter);
6473 if (ret != TRACE_TYPE_NO_CONSUME)
6474 trace_consume(&iter);
6476 touch_nmi_watchdog();
6478 trace_printk_seq(&iter.seq);
6482 printk(KERN_TRACE " (ftrace buffer empty)\n");
6484 printk(KERN_TRACE "---------------------------------\n");
6487 trace_flags |= old_userobj;
6489 for_each_tracing_cpu(cpu) {
6490 atomic_dec(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
6492 atomic_dec(&dump_running);
6493 local_irq_restore(flags);
6495 EXPORT_SYMBOL_GPL(ftrace_dump);
6497 __init static int tracer_alloc_buffers(void)
6503 if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
6506 if (!alloc_cpumask_var(&tracing_cpumask, GFP_KERNEL))
6507 goto out_free_buffer_mask;
6509 /* Only allocate trace_printk buffers if a trace_printk exists */
6510 if (__stop___trace_bprintk_fmt != __start___trace_bprintk_fmt)
6511 /* Must be called before global_trace.buffer is allocated */
6512 trace_printk_init_buffers();
6514 /* To save memory, keep the ring buffer size to its minimum */
6515 if (ring_buffer_expanded)
6516 ring_buf_size = trace_buf_size;
6520 cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
6521 cpumask_copy(tracing_cpumask, cpu_all_mask);
6523 raw_spin_lock_init(&global_trace.start_lock);
6525 /* TODO: make the number of buffers hot pluggable with CPUS */
6526 if (allocate_trace_buffers(&global_trace, ring_buf_size) < 0) {
6527 printk(KERN_ERR "tracer: failed to allocate ring buffer!\n");
6529 goto out_free_cpumask;
6532 if (global_trace.buffer_disabled)
6535 trace_init_cmdlines();
6538 * register_tracer() might reference current_trace, so it
6539 * needs to be set before we register anything. This is
6540 * just a bootstrap of current_trace anyway.
6542 global_trace.current_trace = &nop_trace;
6544 register_tracer(&nop_trace);
6546 /* All seems OK, enable tracing */
6547 tracing_disabled = 0;
6549 atomic_notifier_chain_register(&panic_notifier_list,
6550 &trace_panic_notifier);
6552 register_die_notifier(&trace_die_notifier);
6554 global_trace.flags = TRACE_ARRAY_FL_GLOBAL;
6556 /* Holder for file callbacks */
6557 global_trace.trace_cpu.cpu = RING_BUFFER_ALL_CPUS;
6558 global_trace.trace_cpu.tr = &global_trace;
6560 INIT_LIST_HEAD(&global_trace.systems);
6561 INIT_LIST_HEAD(&global_trace.events);
6562 list_add(&global_trace.list, &ftrace_trace_arrays);
6564 while (trace_boot_options) {
6567 option = strsep(&trace_boot_options, ",");
6568 trace_set_options(&global_trace, option);
6571 register_snapshot_cmd();
6576 free_percpu(global_trace.trace_buffer.data);
6577 #ifdef CONFIG_TRACER_MAX_TRACE
6578 free_percpu(global_trace.max_buffer.data);
6580 free_cpumask_var(tracing_cpumask);
6581 out_free_buffer_mask:
6582 free_cpumask_var(tracing_buffer_mask);
6587 __init static int clear_boot_tracer(void)
6590 * The default tracer at boot buffer is an init section.
6591 * This function is called in lateinit. If we did not
6592 * find the boot tracer, then clear it out, to prevent
6593 * later registration from accessing the buffer that is
6594 * about to be freed.
6596 if (!default_bootup_tracer)
6599 printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n",
6600 default_bootup_tracer);
6601 default_bootup_tracer = NULL;
6606 early_initcall(tracer_alloc_buffers);
6607 fs_initcall(tracer_init_debugfs);
6608 late_initcall(clear_boot_tracer);