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;
427 alloc = sizeof(*entry) + size + 2; /* possible \n added */
429 local_save_flags(irq_flags);
430 buffer = global_trace.trace_buffer.buffer;
431 event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc,
432 irq_flags, preempt_count());
436 entry = ring_buffer_event_data(event);
439 memcpy(&entry->buf, str, size);
441 /* Add a newline if necessary */
442 if (entry->buf[size - 1] != '\n') {
443 entry->buf[size] = '\n';
444 entry->buf[size + 1] = '\0';
446 entry->buf[size] = '\0';
448 __buffer_unlock_commit(buffer, event);
452 EXPORT_SYMBOL_GPL(__trace_puts);
455 * __trace_bputs - write the pointer to a constant string into trace buffer
456 * @ip: The address of the caller
457 * @str: The constant string to write to the buffer to
459 int __trace_bputs(unsigned long ip, const char *str)
461 struct ring_buffer_event *event;
462 struct ring_buffer *buffer;
463 struct bputs_entry *entry;
464 unsigned long irq_flags;
465 int size = sizeof(struct bputs_entry);
467 local_save_flags(irq_flags);
468 buffer = global_trace.trace_buffer.buffer;
469 event = trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size,
470 irq_flags, preempt_count());
474 entry = ring_buffer_event_data(event);
478 __buffer_unlock_commit(buffer, event);
482 EXPORT_SYMBOL_GPL(__trace_bputs);
484 #ifdef CONFIG_TRACER_SNAPSHOT
486 * trace_snapshot - take a snapshot of the current buffer.
488 * This causes a swap between the snapshot buffer and the current live
489 * tracing buffer. You can use this to take snapshots of the live
490 * trace when some condition is triggered, but continue to trace.
492 * Note, make sure to allocate the snapshot with either
493 * a tracing_snapshot_alloc(), or by doing it manually
494 * with: echo 1 > /sys/kernel/debug/tracing/snapshot
496 * If the snapshot buffer is not allocated, it will stop tracing.
497 * Basically making a permanent snapshot.
499 void tracing_snapshot(void)
501 struct trace_array *tr = &global_trace;
502 struct tracer *tracer = tr->current_trace;
506 internal_trace_puts("*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n");
507 internal_trace_puts("*** snapshot is being ignored ***\n");
511 if (!tr->allocated_snapshot) {
512 internal_trace_puts("*** SNAPSHOT NOT ALLOCATED ***\n");
513 internal_trace_puts("*** stopping trace here! ***\n");
518 /* Note, snapshot can not be used when the tracer uses it */
519 if (tracer->use_max_tr) {
520 internal_trace_puts("*** LATENCY TRACER ACTIVE ***\n");
521 internal_trace_puts("*** Can not use snapshot (sorry) ***\n");
525 local_irq_save(flags);
526 update_max_tr(tr, current, smp_processor_id());
527 local_irq_restore(flags);
529 EXPORT_SYMBOL_GPL(tracing_snapshot);
531 static int resize_buffer_duplicate_size(struct trace_buffer *trace_buf,
532 struct trace_buffer *size_buf, int cpu_id);
533 static void set_buffer_entries(struct trace_buffer *buf, unsigned long val);
535 static int alloc_snapshot(struct trace_array *tr)
539 if (!tr->allocated_snapshot) {
541 /* allocate spare buffer */
542 ret = resize_buffer_duplicate_size(&tr->max_buffer,
543 &tr->trace_buffer, RING_BUFFER_ALL_CPUS);
547 tr->allocated_snapshot = true;
553 void free_snapshot(struct trace_array *tr)
556 * We don't free the ring buffer. instead, resize it because
557 * The max_tr ring buffer has some state (e.g. ring->clock) and
558 * we want preserve it.
560 ring_buffer_resize(tr->max_buffer.buffer, 1, RING_BUFFER_ALL_CPUS);
561 set_buffer_entries(&tr->max_buffer, 1);
562 tracing_reset_online_cpus(&tr->max_buffer);
563 tr->allocated_snapshot = false;
567 * trace_snapshot_alloc - allocate and take a snapshot of the current buffer.
569 * This is similar to trace_snapshot(), but it will allocate the
570 * snapshot buffer if it isn't already allocated. Use this only
571 * where it is safe to sleep, as the allocation may sleep.
573 * This causes a swap between the snapshot buffer and the current live
574 * tracing buffer. You can use this to take snapshots of the live
575 * trace when some condition is triggered, but continue to trace.
577 void tracing_snapshot_alloc(void)
579 struct trace_array *tr = &global_trace;
582 ret = alloc_snapshot(tr);
583 if (WARN_ON(ret < 0))
588 EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
590 void tracing_snapshot(void)
592 WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used");
594 EXPORT_SYMBOL_GPL(tracing_snapshot);
595 void tracing_snapshot_alloc(void)
600 EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
601 #endif /* CONFIG_TRACER_SNAPSHOT */
603 void tracer_tracing_off(struct trace_array *tr)
605 if (tr->trace_buffer.buffer)
606 ring_buffer_record_off(tr->trace_buffer.buffer);
608 * This flag is looked at when buffers haven't been allocated
609 * yet, or by some tracers (like irqsoff), that just want to
610 * know if the ring buffer has been disabled, but it can handle
611 * races of where it gets disabled but we still do a record.
612 * As the check is in the fast path of the tracers, it is more
613 * important to be fast than accurate.
615 tr->buffer_disabled = 1;
616 /* Make the flag seen by readers */
621 * tracing_off - turn off tracing buffers
623 * This function stops the tracing buffers from recording data.
624 * It does not disable any overhead the tracers themselves may
625 * be causing. This function simply causes all recording to
626 * the ring buffers to fail.
628 void tracing_off(void)
630 tracer_tracing_off(&global_trace);
632 EXPORT_SYMBOL_GPL(tracing_off);
635 * tracer_tracing_is_on - show real state of ring buffer enabled
636 * @tr : the trace array to know if ring buffer is enabled
638 * Shows real state of the ring buffer if it is enabled or not.
640 int tracer_tracing_is_on(struct trace_array *tr)
642 if (tr->trace_buffer.buffer)
643 return ring_buffer_record_is_on(tr->trace_buffer.buffer);
644 return !tr->buffer_disabled;
648 * tracing_is_on - show state of ring buffers enabled
650 int tracing_is_on(void)
652 return tracer_tracing_is_on(&global_trace);
654 EXPORT_SYMBOL_GPL(tracing_is_on);
656 static int __init set_buf_size(char *str)
658 unsigned long buf_size;
662 buf_size = memparse(str, &str);
663 /* nr_entries can not be zero */
666 trace_buf_size = buf_size;
669 __setup("trace_buf_size=", set_buf_size);
671 static int __init set_tracing_thresh(char *str)
673 unsigned long threshold;
678 ret = kstrtoul(str, 0, &threshold);
681 tracing_thresh = threshold * 1000;
684 __setup("tracing_thresh=", set_tracing_thresh);
686 unsigned long nsecs_to_usecs(unsigned long nsecs)
691 /* These must match the bit postions in trace_iterator_flags */
692 static const char *trace_options[] = {
725 int in_ns; /* is this clock in nanoseconds? */
727 { trace_clock_local, "local", 1 },
728 { trace_clock_global, "global", 1 },
729 { trace_clock_counter, "counter", 0 },
730 { trace_clock_jiffies, "uptime", 1 },
731 { trace_clock, "perf", 1 },
736 * trace_parser_get_init - gets the buffer for trace parser
738 int trace_parser_get_init(struct trace_parser *parser, int size)
740 memset(parser, 0, sizeof(*parser));
742 parser->buffer = kmalloc(size, GFP_KERNEL);
751 * trace_parser_put - frees the buffer for trace parser
753 void trace_parser_put(struct trace_parser *parser)
755 kfree(parser->buffer);
759 * trace_get_user - reads the user input string separated by space
760 * (matched by isspace(ch))
762 * For each string found the 'struct trace_parser' is updated,
763 * and the function returns.
765 * Returns number of bytes read.
767 * See kernel/trace/trace.h for 'struct trace_parser' details.
769 int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
770 size_t cnt, loff_t *ppos)
777 trace_parser_clear(parser);
779 ret = get_user(ch, ubuf++);
787 * The parser is not finished with the last write,
788 * continue reading the user input without skipping spaces.
791 /* skip white space */
792 while (cnt && isspace(ch)) {
793 ret = get_user(ch, ubuf++);
800 /* only spaces were written */
810 /* read the non-space input */
811 while (cnt && !isspace(ch)) {
812 if (parser->idx < parser->size - 1)
813 parser->buffer[parser->idx++] = ch;
818 ret = get_user(ch, ubuf++);
825 /* We either got finished input or we have to wait for another call. */
827 parser->buffer[parser->idx] = 0;
828 parser->cont = false;
831 parser->buffer[parser->idx++] = ch;
841 ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
849 if (s->len <= s->readpos)
852 len = s->len - s->readpos;
855 ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
865 static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
869 if (s->len <= s->readpos)
872 len = s->len - s->readpos;
875 memcpy(buf, s->buffer + s->readpos, cnt);
882 * ftrace_max_lock is used to protect the swapping of buffers
883 * when taking a max snapshot. The buffers themselves are
884 * protected by per_cpu spinlocks. But the action of the swap
885 * needs its own lock.
887 * This is defined as a arch_spinlock_t in order to help
888 * with performance when lockdep debugging is enabled.
890 * It is also used in other places outside the update_max_tr
891 * so it needs to be defined outside of the
892 * CONFIG_TRACER_MAX_TRACE.
894 static arch_spinlock_t ftrace_max_lock =
895 (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
897 unsigned long __read_mostly tracing_thresh;
899 #ifdef CONFIG_TRACER_MAX_TRACE
900 unsigned long __read_mostly tracing_max_latency;
903 * Copy the new maximum trace into the separate maximum-trace
904 * structure. (this way the maximum trace is permanently saved,
905 * for later retrieval via /sys/kernel/debug/tracing/latency_trace)
908 __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
910 struct trace_buffer *trace_buf = &tr->trace_buffer;
911 struct trace_buffer *max_buf = &tr->max_buffer;
912 struct trace_array_cpu *data = per_cpu_ptr(trace_buf->data, cpu);
913 struct trace_array_cpu *max_data = per_cpu_ptr(max_buf->data, cpu);
916 max_buf->time_start = data->preempt_timestamp;
918 max_data->saved_latency = tracing_max_latency;
919 max_data->critical_start = data->critical_start;
920 max_data->critical_end = data->critical_end;
922 memcpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
923 max_data->pid = tsk->pid;
925 * If tsk == current, then use current_uid(), as that does not use
926 * RCU. The irq tracer can be called out of RCU scope.
929 max_data->uid = current_uid();
931 max_data->uid = task_uid(tsk);
933 max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
934 max_data->policy = tsk->policy;
935 max_data->rt_priority = tsk->rt_priority;
937 /* record this tasks comm */
938 tracing_record_cmdline(tsk);
942 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
944 * @tsk: the task with the latency
945 * @cpu: The cpu that initiated the trace.
947 * Flip the buffers between the @tr and the max_tr and record information
948 * about which task was the cause of this latency.
951 update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
953 struct ring_buffer *buf;
958 WARN_ON_ONCE(!irqs_disabled());
960 if (!tr->allocated_snapshot) {
961 /* Only the nop tracer should hit this when disabling */
962 WARN_ON_ONCE(tr->current_trace != &nop_trace);
966 arch_spin_lock(&ftrace_max_lock);
968 buf = tr->trace_buffer.buffer;
969 tr->trace_buffer.buffer = tr->max_buffer.buffer;
970 tr->max_buffer.buffer = buf;
972 __update_max_tr(tr, tsk, cpu);
973 arch_spin_unlock(&ftrace_max_lock);
977 * update_max_tr_single - only copy one trace over, and reset the rest
979 * @tsk - task with the latency
980 * @cpu - the cpu of the buffer to copy.
982 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
985 update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
992 WARN_ON_ONCE(!irqs_disabled());
993 if (!tr->allocated_snapshot) {
994 /* Only the nop tracer should hit this when disabling */
995 WARN_ON_ONCE(tr->current_trace != &nop_trace);
999 arch_spin_lock(&ftrace_max_lock);
1001 ret = ring_buffer_swap_cpu(tr->max_buffer.buffer, tr->trace_buffer.buffer, cpu);
1003 if (ret == -EBUSY) {
1005 * We failed to swap the buffer due to a commit taking
1006 * place on this CPU. We fail to record, but we reset
1007 * the max trace buffer (no one writes directly to it)
1008 * and flag that it failed.
1010 trace_array_printk_buf(tr->max_buffer.buffer, _THIS_IP_,
1011 "Failed to swap buffers due to commit in progress\n");
1014 WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);
1016 __update_max_tr(tr, tsk, cpu);
1017 arch_spin_unlock(&ftrace_max_lock);
1019 #endif /* CONFIG_TRACER_MAX_TRACE */
1021 static void default_wait_pipe(struct trace_iterator *iter)
1023 /* Iterators are static, they should be filled or empty */
1024 if (trace_buffer_iter(iter, iter->cpu_file))
1027 ring_buffer_wait(iter->trace_buffer->buffer, iter->cpu_file);
1030 #ifdef CONFIG_FTRACE_STARTUP_TEST
1031 static int run_tracer_selftest(struct tracer *type)
1033 struct trace_array *tr = &global_trace;
1034 struct tracer *saved_tracer = tr->current_trace;
1037 if (!type->selftest || tracing_selftest_disabled)
1041 * Run a selftest on this tracer.
1042 * Here we reset the trace buffer, and set the current
1043 * tracer to be this tracer. The tracer can then run some
1044 * internal tracing to verify that everything is in order.
1045 * If we fail, we do not register this tracer.
1047 tracing_reset_online_cpus(&tr->trace_buffer);
1049 tr->current_trace = type;
1051 #ifdef CONFIG_TRACER_MAX_TRACE
1052 if (type->use_max_tr) {
1053 /* If we expanded the buffers, make sure the max is expanded too */
1054 if (ring_buffer_expanded)
1055 ring_buffer_resize(tr->max_buffer.buffer, trace_buf_size,
1056 RING_BUFFER_ALL_CPUS);
1057 tr->allocated_snapshot = true;
1061 /* the test is responsible for initializing and enabling */
1062 pr_info("Testing tracer %s: ", type->name);
1063 ret = type->selftest(type, tr);
1064 /* the test is responsible for resetting too */
1065 tr->current_trace = saved_tracer;
1067 printk(KERN_CONT "FAILED!\n");
1068 /* Add the warning after printing 'FAILED' */
1072 /* Only reset on passing, to avoid touching corrupted buffers */
1073 tracing_reset_online_cpus(&tr->trace_buffer);
1075 #ifdef CONFIG_TRACER_MAX_TRACE
1076 if (type->use_max_tr) {
1077 tr->allocated_snapshot = false;
1079 /* Shrink the max buffer again */
1080 if (ring_buffer_expanded)
1081 ring_buffer_resize(tr->max_buffer.buffer, 1,
1082 RING_BUFFER_ALL_CPUS);
1086 printk(KERN_CONT "PASSED\n");
1090 static inline int run_tracer_selftest(struct tracer *type)
1094 #endif /* CONFIG_FTRACE_STARTUP_TEST */
1097 * register_tracer - register a tracer with the ftrace system.
1098 * @type - the plugin for the tracer
1100 * Register a new plugin tracer.
1102 int register_tracer(struct tracer *type)
1108 pr_info("Tracer must have a name\n");
1112 if (strlen(type->name) >= MAX_TRACER_SIZE) {
1113 pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE);
1117 mutex_lock(&trace_types_lock);
1119 tracing_selftest_running = true;
1121 for (t = trace_types; t; t = t->next) {
1122 if (strcmp(type->name, t->name) == 0) {
1124 pr_info("Tracer %s already registered\n",
1131 if (!type->set_flag)
1132 type->set_flag = &dummy_set_flag;
1134 type->flags = &dummy_tracer_flags;
1136 if (!type->flags->opts)
1137 type->flags->opts = dummy_tracer_opt;
1138 if (!type->wait_pipe)
1139 type->wait_pipe = default_wait_pipe;
1141 ret = run_tracer_selftest(type);
1145 type->next = trace_types;
1149 tracing_selftest_running = false;
1150 mutex_unlock(&trace_types_lock);
1152 if (ret || !default_bootup_tracer)
1155 if (strncmp(default_bootup_tracer, type->name, MAX_TRACER_SIZE))
1158 printk(KERN_INFO "Starting tracer '%s'\n", type->name);
1159 /* Do we want this tracer to start on bootup? */
1160 tracing_set_tracer(type->name);
1161 default_bootup_tracer = NULL;
1162 /* disable other selftests, since this will break it. */
1163 tracing_selftest_disabled = true;
1164 #ifdef CONFIG_FTRACE_STARTUP_TEST
1165 printk(KERN_INFO "Disabling FTRACE selftests due to running tracer '%s'\n",
1173 void tracing_reset(struct trace_buffer *buf, int cpu)
1175 struct ring_buffer *buffer = buf->buffer;
1180 ring_buffer_record_disable(buffer);
1182 /* Make sure all commits have finished */
1183 synchronize_sched();
1184 ring_buffer_reset_cpu(buffer, cpu);
1186 ring_buffer_record_enable(buffer);
1189 void tracing_reset_online_cpus(struct trace_buffer *buf)
1191 struct ring_buffer *buffer = buf->buffer;
1197 ring_buffer_record_disable(buffer);
1199 /* Make sure all commits have finished */
1200 synchronize_sched();
1202 buf->time_start = buffer_ftrace_now(buf, buf->cpu);
1204 for_each_online_cpu(cpu)
1205 ring_buffer_reset_cpu(buffer, cpu);
1207 ring_buffer_record_enable(buffer);
1210 /* Must have trace_types_lock held */
1211 void tracing_reset_all_online_cpus(void)
1213 struct trace_array *tr;
1215 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
1216 tracing_reset_online_cpus(&tr->trace_buffer);
1217 #ifdef CONFIG_TRACER_MAX_TRACE
1218 tracing_reset_online_cpus(&tr->max_buffer);
1223 #define SAVED_CMDLINES 128
1224 #define NO_CMDLINE_MAP UINT_MAX
1225 static unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
1226 static unsigned map_cmdline_to_pid[SAVED_CMDLINES];
1227 static char saved_cmdlines[SAVED_CMDLINES][TASK_COMM_LEN];
1228 static int cmdline_idx;
1229 static arch_spinlock_t trace_cmdline_lock = __ARCH_SPIN_LOCK_UNLOCKED;
1231 /* temporary disable recording */
1232 static atomic_t trace_record_cmdline_disabled __read_mostly;
1234 static void trace_init_cmdlines(void)
1236 memset(&map_pid_to_cmdline, NO_CMDLINE_MAP, sizeof(map_pid_to_cmdline));
1237 memset(&map_cmdline_to_pid, NO_CMDLINE_MAP, sizeof(map_cmdline_to_pid));
1241 int is_tracing_stopped(void)
1243 return global_trace.stop_count;
1247 * ftrace_off_permanent - disable all ftrace code permanently
1249 * This should only be called when a serious anomally has
1250 * been detected. This will turn off the function tracing,
1251 * ring buffers, and other tracing utilites. It takes no
1252 * locks and can be called from any context.
1254 void ftrace_off_permanent(void)
1256 tracing_disabled = 1;
1258 tracing_off_permanent();
1262 * tracing_start - quick start of the tracer
1264 * If tracing is enabled but was stopped by tracing_stop,
1265 * this will start the tracer back up.
1267 void tracing_start(void)
1269 struct ring_buffer *buffer;
1270 unsigned long flags;
1272 if (tracing_disabled)
1275 raw_spin_lock_irqsave(&global_trace.start_lock, flags);
1276 if (--global_trace.stop_count) {
1277 if (global_trace.stop_count < 0) {
1278 /* Someone screwed up their debugging */
1280 global_trace.stop_count = 0;
1285 /* Prevent the buffers from switching */
1286 arch_spin_lock(&ftrace_max_lock);
1288 buffer = global_trace.trace_buffer.buffer;
1290 ring_buffer_record_enable(buffer);
1292 #ifdef CONFIG_TRACER_MAX_TRACE
1293 buffer = global_trace.max_buffer.buffer;
1295 ring_buffer_record_enable(buffer);
1298 arch_spin_unlock(&ftrace_max_lock);
1302 raw_spin_unlock_irqrestore(&global_trace.start_lock, flags);
1305 static void tracing_start_tr(struct trace_array *tr)
1307 struct ring_buffer *buffer;
1308 unsigned long flags;
1310 if (tracing_disabled)
1313 /* If global, we need to also start the max tracer */
1314 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
1315 return tracing_start();
1317 raw_spin_lock_irqsave(&tr->start_lock, flags);
1319 if (--tr->stop_count) {
1320 if (tr->stop_count < 0) {
1321 /* Someone screwed up their debugging */
1328 buffer = tr->trace_buffer.buffer;
1330 ring_buffer_record_enable(buffer);
1333 raw_spin_unlock_irqrestore(&tr->start_lock, flags);
1337 * tracing_stop - quick stop of the tracer
1339 * Light weight way to stop tracing. Use in conjunction with
1342 void tracing_stop(void)
1344 struct ring_buffer *buffer;
1345 unsigned long flags;
1348 raw_spin_lock_irqsave(&global_trace.start_lock, flags);
1349 if (global_trace.stop_count++)
1352 /* Prevent the buffers from switching */
1353 arch_spin_lock(&ftrace_max_lock);
1355 buffer = global_trace.trace_buffer.buffer;
1357 ring_buffer_record_disable(buffer);
1359 #ifdef CONFIG_TRACER_MAX_TRACE
1360 buffer = global_trace.max_buffer.buffer;
1362 ring_buffer_record_disable(buffer);
1365 arch_spin_unlock(&ftrace_max_lock);
1368 raw_spin_unlock_irqrestore(&global_trace.start_lock, flags);
1371 static void tracing_stop_tr(struct trace_array *tr)
1373 struct ring_buffer *buffer;
1374 unsigned long flags;
1376 /* If global, we need to also stop the max tracer */
1377 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
1378 return tracing_stop();
1380 raw_spin_lock_irqsave(&tr->start_lock, flags);
1381 if (tr->stop_count++)
1384 buffer = tr->trace_buffer.buffer;
1386 ring_buffer_record_disable(buffer);
1389 raw_spin_unlock_irqrestore(&tr->start_lock, flags);
1392 void trace_stop_cmdline_recording(void);
1394 static void trace_save_cmdline(struct task_struct *tsk)
1398 if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT))
1402 * It's not the end of the world if we don't get
1403 * the lock, but we also don't want to spin
1404 * nor do we want to disable interrupts,
1405 * so if we miss here, then better luck next time.
1407 if (!arch_spin_trylock(&trace_cmdline_lock))
1410 idx = map_pid_to_cmdline[tsk->pid];
1411 if (idx == NO_CMDLINE_MAP) {
1412 idx = (cmdline_idx + 1) % SAVED_CMDLINES;
1415 * Check whether the cmdline buffer at idx has a pid
1416 * mapped. We are going to overwrite that entry so we
1417 * need to clear the map_pid_to_cmdline. Otherwise we
1418 * would read the new comm for the old pid.
1420 pid = map_cmdline_to_pid[idx];
1421 if (pid != NO_CMDLINE_MAP)
1422 map_pid_to_cmdline[pid] = NO_CMDLINE_MAP;
1424 map_cmdline_to_pid[idx] = tsk->pid;
1425 map_pid_to_cmdline[tsk->pid] = idx;
1430 memcpy(&saved_cmdlines[idx], tsk->comm, TASK_COMM_LEN);
1432 arch_spin_unlock(&trace_cmdline_lock);
1435 void trace_find_cmdline(int pid, char comm[])
1440 strcpy(comm, "<idle>");
1444 if (WARN_ON_ONCE(pid < 0)) {
1445 strcpy(comm, "<XXX>");
1449 if (pid > PID_MAX_DEFAULT) {
1450 strcpy(comm, "<...>");
1455 arch_spin_lock(&trace_cmdline_lock);
1456 map = map_pid_to_cmdline[pid];
1457 if (map != NO_CMDLINE_MAP)
1458 strcpy(comm, saved_cmdlines[map]);
1460 strcpy(comm, "<...>");
1462 arch_spin_unlock(&trace_cmdline_lock);
1466 void tracing_record_cmdline(struct task_struct *tsk)
1468 if (atomic_read(&trace_record_cmdline_disabled) || !tracing_is_on())
1471 if (!__this_cpu_read(trace_cmdline_save))
1474 __this_cpu_write(trace_cmdline_save, false);
1476 trace_save_cmdline(tsk);
1480 tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
1483 struct task_struct *tsk = current;
1485 entry->preempt_count = pc & 0xff;
1486 entry->pid = (tsk) ? tsk->pid : 0;
1488 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
1489 (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
1491 TRACE_FLAG_IRQS_NOSUPPORT |
1493 ((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
1494 ((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
1495 (need_resched() ? TRACE_FLAG_NEED_RESCHED : 0);
1497 EXPORT_SYMBOL_GPL(tracing_generic_entry_update);
1499 struct ring_buffer_event *
1500 trace_buffer_lock_reserve(struct ring_buffer *buffer,
1503 unsigned long flags, int pc)
1505 struct ring_buffer_event *event;
1507 event = ring_buffer_lock_reserve(buffer, len);
1508 if (event != NULL) {
1509 struct trace_entry *ent = ring_buffer_event_data(event);
1511 tracing_generic_entry_update(ent, flags, pc);
1519 __buffer_unlock_commit(struct ring_buffer *buffer, struct ring_buffer_event *event)
1521 __this_cpu_write(trace_cmdline_save, true);
1522 ring_buffer_unlock_commit(buffer, event);
1526 __trace_buffer_unlock_commit(struct ring_buffer *buffer,
1527 struct ring_buffer_event *event,
1528 unsigned long flags, int pc)
1530 __buffer_unlock_commit(buffer, event);
1532 ftrace_trace_stack(buffer, flags, 6, pc);
1533 ftrace_trace_userstack(buffer, flags, pc);
1536 void trace_buffer_unlock_commit(struct ring_buffer *buffer,
1537 struct ring_buffer_event *event,
1538 unsigned long flags, int pc)
1540 __trace_buffer_unlock_commit(buffer, event, flags, pc);
1542 EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit);
1544 struct ring_buffer_event *
1545 trace_event_buffer_lock_reserve(struct ring_buffer **current_rb,
1546 struct ftrace_event_file *ftrace_file,
1547 int type, unsigned long len,
1548 unsigned long flags, int pc)
1550 *current_rb = ftrace_file->tr->trace_buffer.buffer;
1551 return trace_buffer_lock_reserve(*current_rb,
1552 type, len, flags, pc);
1554 EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve);
1556 struct ring_buffer_event *
1557 trace_current_buffer_lock_reserve(struct ring_buffer **current_rb,
1558 int type, unsigned long len,
1559 unsigned long flags, int pc)
1561 *current_rb = global_trace.trace_buffer.buffer;
1562 return trace_buffer_lock_reserve(*current_rb,
1563 type, len, flags, pc);
1565 EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve);
1567 void trace_current_buffer_unlock_commit(struct ring_buffer *buffer,
1568 struct ring_buffer_event *event,
1569 unsigned long flags, int pc)
1571 __trace_buffer_unlock_commit(buffer, event, flags, pc);
1573 EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit);
1575 void trace_buffer_unlock_commit_regs(struct ring_buffer *buffer,
1576 struct ring_buffer_event *event,
1577 unsigned long flags, int pc,
1578 struct pt_regs *regs)
1580 __buffer_unlock_commit(buffer, event);
1582 ftrace_trace_stack_regs(buffer, flags, 0, pc, regs);
1583 ftrace_trace_userstack(buffer, flags, pc);
1585 EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit_regs);
1587 void trace_current_buffer_discard_commit(struct ring_buffer *buffer,
1588 struct ring_buffer_event *event)
1590 ring_buffer_discard_commit(buffer, event);
1592 EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit);
1595 trace_function(struct trace_array *tr,
1596 unsigned long ip, unsigned long parent_ip, unsigned long flags,
1599 struct ftrace_event_call *call = &event_function;
1600 struct ring_buffer *buffer = tr->trace_buffer.buffer;
1601 struct ring_buffer_event *event;
1602 struct ftrace_entry *entry;
1604 /* If we are reading the ring buffer, don't trace */
1605 if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))
1608 event = trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
1612 entry = ring_buffer_event_data(event);
1614 entry->parent_ip = parent_ip;
1616 if (!filter_check_discard(call, entry, buffer, event))
1617 __buffer_unlock_commit(buffer, event);
1621 ftrace(struct trace_array *tr, struct trace_array_cpu *data,
1622 unsigned long ip, unsigned long parent_ip, unsigned long flags,
1625 if (likely(!atomic_read(&data->disabled)))
1626 trace_function(tr, ip, parent_ip, flags, pc);
1629 #ifdef CONFIG_STACKTRACE
1631 #define FTRACE_STACK_MAX_ENTRIES (PAGE_SIZE / sizeof(unsigned long))
1632 struct ftrace_stack {
1633 unsigned long calls[FTRACE_STACK_MAX_ENTRIES];
1636 static DEFINE_PER_CPU(struct ftrace_stack, ftrace_stack);
1637 static DEFINE_PER_CPU(int, ftrace_stack_reserve);
1639 static void __ftrace_trace_stack(struct ring_buffer *buffer,
1640 unsigned long flags,
1641 int skip, int pc, struct pt_regs *regs)
1643 struct ftrace_event_call *call = &event_kernel_stack;
1644 struct ring_buffer_event *event;
1645 struct stack_entry *entry;
1646 struct stack_trace trace;
1648 int size = FTRACE_STACK_ENTRIES;
1650 trace.nr_entries = 0;
1654 * Since events can happen in NMIs there's no safe way to
1655 * use the per cpu ftrace_stacks. We reserve it and if an interrupt
1656 * or NMI comes in, it will just have to use the default
1657 * FTRACE_STACK_SIZE.
1659 preempt_disable_notrace();
1661 use_stack = __this_cpu_inc_return(ftrace_stack_reserve);
1663 * We don't need any atomic variables, just a barrier.
1664 * If an interrupt comes in, we don't care, because it would
1665 * have exited and put the counter back to what we want.
1666 * We just need a barrier to keep gcc from moving things
1670 if (use_stack == 1) {
1671 trace.entries = &__get_cpu_var(ftrace_stack).calls[0];
1672 trace.max_entries = FTRACE_STACK_MAX_ENTRIES;
1675 save_stack_trace_regs(regs, &trace);
1677 save_stack_trace(&trace);
1679 if (trace.nr_entries > size)
1680 size = trace.nr_entries;
1682 /* From now on, use_stack is a boolean */
1685 size *= sizeof(unsigned long);
1687 event = trace_buffer_lock_reserve(buffer, TRACE_STACK,
1688 sizeof(*entry) + size, flags, pc);
1691 entry = ring_buffer_event_data(event);
1693 memset(&entry->caller, 0, size);
1696 memcpy(&entry->caller, trace.entries,
1697 trace.nr_entries * sizeof(unsigned long));
1699 trace.max_entries = FTRACE_STACK_ENTRIES;
1700 trace.entries = entry->caller;
1702 save_stack_trace_regs(regs, &trace);
1704 save_stack_trace(&trace);
1707 entry->size = trace.nr_entries;
1709 if (!filter_check_discard(call, entry, buffer, event))
1710 __buffer_unlock_commit(buffer, event);
1713 /* Again, don't let gcc optimize things here */
1715 __this_cpu_dec(ftrace_stack_reserve);
1716 preempt_enable_notrace();
1720 void ftrace_trace_stack_regs(struct ring_buffer *buffer, unsigned long flags,
1721 int skip, int pc, struct pt_regs *regs)
1723 if (!(trace_flags & TRACE_ITER_STACKTRACE))
1726 __ftrace_trace_stack(buffer, flags, skip, pc, regs);
1729 void ftrace_trace_stack(struct ring_buffer *buffer, unsigned long flags,
1732 if (!(trace_flags & TRACE_ITER_STACKTRACE))
1735 __ftrace_trace_stack(buffer, flags, skip, pc, NULL);
1738 void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
1741 __ftrace_trace_stack(tr->trace_buffer.buffer, flags, skip, pc, NULL);
1745 * trace_dump_stack - record a stack back trace in the trace buffer
1746 * @skip: Number of functions to skip (helper handlers)
1748 void trace_dump_stack(int skip)
1750 unsigned long flags;
1752 if (tracing_disabled || tracing_selftest_running)
1755 local_save_flags(flags);
1758 * Skip 3 more, seems to get us at the caller of
1762 __ftrace_trace_stack(global_trace.trace_buffer.buffer,
1763 flags, skip, preempt_count(), NULL);
1766 static DEFINE_PER_CPU(int, user_stack_count);
1769 ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
1771 struct ftrace_event_call *call = &event_user_stack;
1772 struct ring_buffer_event *event;
1773 struct userstack_entry *entry;
1774 struct stack_trace trace;
1776 if (!(trace_flags & TRACE_ITER_USERSTACKTRACE))
1780 * NMIs can not handle page faults, even with fix ups.
1781 * The save user stack can (and often does) fault.
1783 if (unlikely(in_nmi()))
1787 * prevent recursion, since the user stack tracing may
1788 * trigger other kernel events.
1791 if (__this_cpu_read(user_stack_count))
1794 __this_cpu_inc(user_stack_count);
1796 event = trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
1797 sizeof(*entry), flags, pc);
1799 goto out_drop_count;
1800 entry = ring_buffer_event_data(event);
1802 entry->tgid = current->tgid;
1803 memset(&entry->caller, 0, sizeof(entry->caller));
1805 trace.nr_entries = 0;
1806 trace.max_entries = FTRACE_STACK_ENTRIES;
1808 trace.entries = entry->caller;
1810 save_stack_trace_user(&trace);
1811 if (!filter_check_discard(call, entry, buffer, event))
1812 __buffer_unlock_commit(buffer, event);
1815 __this_cpu_dec(user_stack_count);
1821 static void __trace_userstack(struct trace_array *tr, unsigned long flags)
1823 ftrace_trace_userstack(tr, flags, preempt_count());
1827 #endif /* CONFIG_STACKTRACE */
1829 /* created for use with alloc_percpu */
1830 struct trace_buffer_struct {
1831 char buffer[TRACE_BUF_SIZE];
1834 static struct trace_buffer_struct *trace_percpu_buffer;
1835 static struct trace_buffer_struct *trace_percpu_sirq_buffer;
1836 static struct trace_buffer_struct *trace_percpu_irq_buffer;
1837 static struct trace_buffer_struct *trace_percpu_nmi_buffer;
1840 * The buffer used is dependent on the context. There is a per cpu
1841 * buffer for normal context, softirq contex, hard irq context and
1842 * for NMI context. Thise allows for lockless recording.
1844 * Note, if the buffers failed to be allocated, then this returns NULL
1846 static char *get_trace_buf(void)
1848 struct trace_buffer_struct *percpu_buffer;
1851 * If we have allocated per cpu buffers, then we do not
1852 * need to do any locking.
1855 percpu_buffer = trace_percpu_nmi_buffer;
1857 percpu_buffer = trace_percpu_irq_buffer;
1858 else if (in_softirq())
1859 percpu_buffer = trace_percpu_sirq_buffer;
1861 percpu_buffer = trace_percpu_buffer;
1866 return this_cpu_ptr(&percpu_buffer->buffer[0]);
1869 static int alloc_percpu_trace_buffer(void)
1871 struct trace_buffer_struct *buffers;
1872 struct trace_buffer_struct *sirq_buffers;
1873 struct trace_buffer_struct *irq_buffers;
1874 struct trace_buffer_struct *nmi_buffers;
1876 buffers = alloc_percpu(struct trace_buffer_struct);
1880 sirq_buffers = alloc_percpu(struct trace_buffer_struct);
1884 irq_buffers = alloc_percpu(struct trace_buffer_struct);
1888 nmi_buffers = alloc_percpu(struct trace_buffer_struct);
1892 trace_percpu_buffer = buffers;
1893 trace_percpu_sirq_buffer = sirq_buffers;
1894 trace_percpu_irq_buffer = irq_buffers;
1895 trace_percpu_nmi_buffer = nmi_buffers;
1900 free_percpu(irq_buffers);
1902 free_percpu(sirq_buffers);
1904 free_percpu(buffers);
1906 WARN(1, "Could not allocate percpu trace_printk buffer");
1910 static int buffers_allocated;
1912 void trace_printk_init_buffers(void)
1914 if (buffers_allocated)
1917 if (alloc_percpu_trace_buffer())
1920 pr_info("ftrace: Allocated trace_printk buffers\n");
1922 /* Expand the buffers to set size */
1923 tracing_update_buffers();
1925 buffers_allocated = 1;
1928 * trace_printk_init_buffers() can be called by modules.
1929 * If that happens, then we need to start cmdline recording
1930 * directly here. If the global_trace.buffer is already
1931 * allocated here, then this was called by module code.
1933 if (global_trace.trace_buffer.buffer)
1934 tracing_start_cmdline_record();
1937 void trace_printk_start_comm(void)
1939 /* Start tracing comms if trace printk is set */
1940 if (!buffers_allocated)
1942 tracing_start_cmdline_record();
1945 static void trace_printk_start_stop_comm(int enabled)
1947 if (!buffers_allocated)
1951 tracing_start_cmdline_record();
1953 tracing_stop_cmdline_record();
1957 * trace_vbprintk - write binary msg to tracing buffer
1960 int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
1962 struct ftrace_event_call *call = &event_bprint;
1963 struct ring_buffer_event *event;
1964 struct ring_buffer *buffer;
1965 struct trace_array *tr = &global_trace;
1966 struct bprint_entry *entry;
1967 unsigned long flags;
1969 int len = 0, size, pc;
1971 if (unlikely(tracing_selftest_running || tracing_disabled))
1974 /* Don't pollute graph traces with trace_vprintk internals */
1975 pause_graph_tracing();
1977 pc = preempt_count();
1978 preempt_disable_notrace();
1980 tbuffer = get_trace_buf();
1986 len = vbin_printf((u32 *)tbuffer, TRACE_BUF_SIZE/sizeof(int), fmt, args);
1988 if (len > TRACE_BUF_SIZE/sizeof(int) || len < 0)
1991 local_save_flags(flags);
1992 size = sizeof(*entry) + sizeof(u32) * len;
1993 buffer = tr->trace_buffer.buffer;
1994 event = trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
1998 entry = ring_buffer_event_data(event);
2002 memcpy(entry->buf, tbuffer, sizeof(u32) * len);
2003 if (!filter_check_discard(call, entry, buffer, event)) {
2004 __buffer_unlock_commit(buffer, event);
2005 ftrace_trace_stack(buffer, flags, 6, pc);
2009 preempt_enable_notrace();
2010 unpause_graph_tracing();
2014 EXPORT_SYMBOL_GPL(trace_vbprintk);
2017 __trace_array_vprintk(struct ring_buffer *buffer,
2018 unsigned long ip, const char *fmt, va_list args)
2020 struct ftrace_event_call *call = &event_print;
2021 struct ring_buffer_event *event;
2022 int len = 0, size, pc;
2023 struct print_entry *entry;
2024 unsigned long flags;
2027 if (tracing_disabled || tracing_selftest_running)
2030 /* Don't pollute graph traces with trace_vprintk internals */
2031 pause_graph_tracing();
2033 pc = preempt_count();
2034 preempt_disable_notrace();
2037 tbuffer = get_trace_buf();
2043 len = vsnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args);
2044 if (len > TRACE_BUF_SIZE)
2047 local_save_flags(flags);
2048 size = sizeof(*entry) + len + 1;
2049 event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
2053 entry = ring_buffer_event_data(event);
2056 memcpy(&entry->buf, tbuffer, len);
2057 entry->buf[len] = '\0';
2058 if (!filter_check_discard(call, entry, buffer, event)) {
2059 __buffer_unlock_commit(buffer, event);
2060 ftrace_trace_stack(buffer, flags, 6, pc);
2063 preempt_enable_notrace();
2064 unpause_graph_tracing();
2069 int trace_array_vprintk(struct trace_array *tr,
2070 unsigned long ip, const char *fmt, va_list args)
2072 return __trace_array_vprintk(tr->trace_buffer.buffer, ip, fmt, args);
2075 int trace_array_printk(struct trace_array *tr,
2076 unsigned long ip, const char *fmt, ...)
2081 if (!(trace_flags & TRACE_ITER_PRINTK))
2085 ret = trace_array_vprintk(tr, ip, fmt, ap);
2090 int trace_array_printk_buf(struct ring_buffer *buffer,
2091 unsigned long ip, const char *fmt, ...)
2096 if (!(trace_flags & TRACE_ITER_PRINTK))
2100 ret = __trace_array_vprintk(buffer, ip, fmt, ap);
2105 int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
2107 return trace_array_vprintk(&global_trace, ip, fmt, args);
2109 EXPORT_SYMBOL_GPL(trace_vprintk);
2111 static void trace_iterator_increment(struct trace_iterator *iter)
2113 struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, iter->cpu);
2117 ring_buffer_read(buf_iter, NULL);
2120 static struct trace_entry *
2121 peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts,
2122 unsigned long *lost_events)
2124 struct ring_buffer_event *event;
2125 struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, cpu);
2128 event = ring_buffer_iter_peek(buf_iter, ts);
2130 event = ring_buffer_peek(iter->trace_buffer->buffer, cpu, ts,
2134 iter->ent_size = ring_buffer_event_length(event);
2135 return ring_buffer_event_data(event);
2141 static struct trace_entry *
2142 __find_next_entry(struct trace_iterator *iter, int *ent_cpu,
2143 unsigned long *missing_events, u64 *ent_ts)
2145 struct ring_buffer *buffer = iter->trace_buffer->buffer;
2146 struct trace_entry *ent, *next = NULL;
2147 unsigned long lost_events = 0, next_lost = 0;
2148 int cpu_file = iter->cpu_file;
2149 u64 next_ts = 0, ts;
2155 * If we are in a per_cpu trace file, don't bother by iterating over
2156 * all cpu and peek directly.
2158 if (cpu_file > RING_BUFFER_ALL_CPUS) {
2159 if (ring_buffer_empty_cpu(buffer, cpu_file))
2161 ent = peek_next_entry(iter, cpu_file, ent_ts, missing_events);
2163 *ent_cpu = cpu_file;
2168 for_each_tracing_cpu(cpu) {
2170 if (ring_buffer_empty_cpu(buffer, cpu))
2173 ent = peek_next_entry(iter, cpu, &ts, &lost_events);
2176 * Pick the entry with the smallest timestamp:
2178 if (ent && (!next || ts < next_ts)) {
2182 next_lost = lost_events;
2183 next_size = iter->ent_size;
2187 iter->ent_size = next_size;
2190 *ent_cpu = next_cpu;
2196 *missing_events = next_lost;
2201 /* Find the next real entry, without updating the iterator itself */
2202 struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
2203 int *ent_cpu, u64 *ent_ts)
2205 return __find_next_entry(iter, ent_cpu, NULL, ent_ts);
2208 /* Find the next real entry, and increment the iterator to the next entry */
2209 void *trace_find_next_entry_inc(struct trace_iterator *iter)
2211 iter->ent = __find_next_entry(iter, &iter->cpu,
2212 &iter->lost_events, &iter->ts);
2215 trace_iterator_increment(iter);
2217 return iter->ent ? iter : NULL;
2220 static void trace_consume(struct trace_iterator *iter)
2222 ring_buffer_consume(iter->trace_buffer->buffer, iter->cpu, &iter->ts,
2223 &iter->lost_events);
2226 static void *s_next(struct seq_file *m, void *v, loff_t *pos)
2228 struct trace_iterator *iter = m->private;
2232 WARN_ON_ONCE(iter->leftover);
2236 /* can't go backwards */
2241 ent = trace_find_next_entry_inc(iter);
2245 while (ent && iter->idx < i)
2246 ent = trace_find_next_entry_inc(iter);
2253 void tracing_iter_reset(struct trace_iterator *iter, int cpu)
2255 struct ring_buffer_event *event;
2256 struct ring_buffer_iter *buf_iter;
2257 unsigned long entries = 0;
2260 per_cpu_ptr(iter->trace_buffer->data, cpu)->skipped_entries = 0;
2262 buf_iter = trace_buffer_iter(iter, cpu);
2266 ring_buffer_iter_reset(buf_iter);
2269 * We could have the case with the max latency tracers
2270 * that a reset never took place on a cpu. This is evident
2271 * by the timestamp being before the start of the buffer.
2273 while ((event = ring_buffer_iter_peek(buf_iter, &ts))) {
2274 if (ts >= iter->trace_buffer->time_start)
2277 ring_buffer_read(buf_iter, NULL);
2280 per_cpu_ptr(iter->trace_buffer->data, cpu)->skipped_entries = entries;
2284 * The current tracer is copied to avoid a global locking
2287 static void *s_start(struct seq_file *m, loff_t *pos)
2289 struct trace_iterator *iter = m->private;
2290 struct trace_array *tr = iter->tr;
2291 int cpu_file = iter->cpu_file;
2297 * copy the tracer to avoid using a global lock all around.
2298 * iter->trace is a copy of current_trace, the pointer to the
2299 * name may be used instead of a strcmp(), as iter->trace->name
2300 * will point to the same string as current_trace->name.
2302 mutex_lock(&trace_types_lock);
2303 if (unlikely(tr->current_trace && iter->trace->name != tr->current_trace->name))
2304 *iter->trace = *tr->current_trace;
2305 mutex_unlock(&trace_types_lock);
2307 #ifdef CONFIG_TRACER_MAX_TRACE
2308 if (iter->snapshot && iter->trace->use_max_tr)
2309 return ERR_PTR(-EBUSY);
2312 if (!iter->snapshot)
2313 atomic_inc(&trace_record_cmdline_disabled);
2315 if (*pos != iter->pos) {
2320 if (cpu_file == RING_BUFFER_ALL_CPUS) {
2321 for_each_tracing_cpu(cpu)
2322 tracing_iter_reset(iter, cpu);
2324 tracing_iter_reset(iter, cpu_file);
2327 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
2332 * If we overflowed the seq_file before, then we want
2333 * to just reuse the trace_seq buffer again.
2339 p = s_next(m, p, &l);
2343 trace_event_read_lock();
2344 trace_access_lock(cpu_file);
2348 static void s_stop(struct seq_file *m, void *p)
2350 struct trace_iterator *iter = m->private;
2352 #ifdef CONFIG_TRACER_MAX_TRACE
2353 if (iter->snapshot && iter->trace->use_max_tr)
2357 if (!iter->snapshot)
2358 atomic_dec(&trace_record_cmdline_disabled);
2360 trace_access_unlock(iter->cpu_file);
2361 trace_event_read_unlock();
2365 get_total_entries(struct trace_buffer *buf,
2366 unsigned long *total, unsigned long *entries)
2368 unsigned long count;
2374 for_each_tracing_cpu(cpu) {
2375 count = ring_buffer_entries_cpu(buf->buffer, cpu);
2377 * If this buffer has skipped entries, then we hold all
2378 * entries for the trace and we need to ignore the
2379 * ones before the time stamp.
2381 if (per_cpu_ptr(buf->data, cpu)->skipped_entries) {
2382 count -= per_cpu_ptr(buf->data, cpu)->skipped_entries;
2383 /* total is the same as the entries */
2387 ring_buffer_overrun_cpu(buf->buffer, cpu);
2392 static void print_lat_help_header(struct seq_file *m)
2394 seq_puts(m, "# _------=> CPU# \n");
2395 seq_puts(m, "# / _-----=> irqs-off \n");
2396 seq_puts(m, "# | / _----=> need-resched \n");
2397 seq_puts(m, "# || / _---=> hardirq/softirq \n");
2398 seq_puts(m, "# ||| / _--=> preempt-depth \n");
2399 seq_puts(m, "# |||| / delay \n");
2400 seq_puts(m, "# cmd pid ||||| time | caller \n");
2401 seq_puts(m, "# \\ / ||||| \\ | / \n");
2404 static void print_event_info(struct trace_buffer *buf, struct seq_file *m)
2406 unsigned long total;
2407 unsigned long entries;
2409 get_total_entries(buf, &total, &entries);
2410 seq_printf(m, "# entries-in-buffer/entries-written: %lu/%lu #P:%d\n",
2411 entries, total, num_online_cpus());
2415 static void print_func_help_header(struct trace_buffer *buf, struct seq_file *m)
2417 print_event_info(buf, m);
2418 seq_puts(m, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
2419 seq_puts(m, "# | | | | |\n");
2422 static void print_func_help_header_irq(struct trace_buffer *buf, struct seq_file *m)
2424 print_event_info(buf, m);
2425 seq_puts(m, "# _-----=> irqs-off\n");
2426 seq_puts(m, "# / _----=> need-resched\n");
2427 seq_puts(m, "# | / _---=> hardirq/softirq\n");
2428 seq_puts(m, "# || / _--=> preempt-depth\n");
2429 seq_puts(m, "# ||| / delay\n");
2430 seq_puts(m, "# TASK-PID CPU# |||| TIMESTAMP FUNCTION\n");
2431 seq_puts(m, "# | | | |||| | |\n");
2435 print_trace_header(struct seq_file *m, struct trace_iterator *iter)
2437 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
2438 struct trace_buffer *buf = iter->trace_buffer;
2439 struct trace_array_cpu *data = per_cpu_ptr(buf->data, buf->cpu);
2440 struct tracer *type = iter->trace;
2441 unsigned long entries;
2442 unsigned long total;
2443 const char *name = "preemption";
2447 get_total_entries(buf, &total, &entries);
2449 seq_printf(m, "# %s latency trace v1.1.5 on %s\n",
2451 seq_puts(m, "# -----------------------------------"
2452 "---------------------------------\n");
2453 seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d |"
2454 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
2455 nsecs_to_usecs(data->saved_latency),
2459 #if defined(CONFIG_PREEMPT_NONE)
2461 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
2463 #elif defined(CONFIG_PREEMPT)
2468 /* These are reserved for later use */
2471 seq_printf(m, " #P:%d)\n", num_online_cpus());
2475 seq_puts(m, "# -----------------\n");
2476 seq_printf(m, "# | task: %.16s-%d "
2477 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
2478 data->comm, data->pid,
2479 from_kuid_munged(seq_user_ns(m), data->uid), data->nice,
2480 data->policy, data->rt_priority);
2481 seq_puts(m, "# -----------------\n");
2483 if (data->critical_start) {
2484 seq_puts(m, "# => started at: ");
2485 seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
2486 trace_print_seq(m, &iter->seq);
2487 seq_puts(m, "\n# => ended at: ");
2488 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
2489 trace_print_seq(m, &iter->seq);
2490 seq_puts(m, "\n#\n");
2496 static void test_cpu_buff_start(struct trace_iterator *iter)
2498 struct trace_seq *s = &iter->seq;
2500 if (!(trace_flags & TRACE_ITER_ANNOTATE))
2503 if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
2506 if (cpumask_test_cpu(iter->cpu, iter->started))
2509 if (per_cpu_ptr(iter->trace_buffer->data, iter->cpu)->skipped_entries)
2512 cpumask_set_cpu(iter->cpu, iter->started);
2514 /* Don't print started cpu buffer for the first entry of the trace */
2516 trace_seq_printf(s, "##### CPU %u buffer started ####\n",
2520 static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
2522 struct trace_seq *s = &iter->seq;
2523 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
2524 struct trace_entry *entry;
2525 struct trace_event *event;
2529 test_cpu_buff_start(iter);
2531 event = ftrace_find_event(entry->type);
2533 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
2534 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
2535 if (!trace_print_lat_context(iter))
2538 if (!trace_print_context(iter))
2544 return event->funcs->trace(iter, sym_flags, event);
2546 if (!trace_seq_printf(s, "Unknown type %d\n", entry->type))
2549 return TRACE_TYPE_HANDLED;
2551 return TRACE_TYPE_PARTIAL_LINE;
2554 static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
2556 struct trace_seq *s = &iter->seq;
2557 struct trace_entry *entry;
2558 struct trace_event *event;
2562 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
2563 if (!trace_seq_printf(s, "%d %d %llu ",
2564 entry->pid, iter->cpu, iter->ts))
2568 event = ftrace_find_event(entry->type);
2570 return event->funcs->raw(iter, 0, event);
2572 if (!trace_seq_printf(s, "%d ?\n", entry->type))
2575 return TRACE_TYPE_HANDLED;
2577 return TRACE_TYPE_PARTIAL_LINE;
2580 static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
2582 struct trace_seq *s = &iter->seq;
2583 unsigned char newline = '\n';
2584 struct trace_entry *entry;
2585 struct trace_event *event;
2589 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
2590 SEQ_PUT_HEX_FIELD_RET(s, entry->pid);
2591 SEQ_PUT_HEX_FIELD_RET(s, iter->cpu);
2592 SEQ_PUT_HEX_FIELD_RET(s, iter->ts);
2595 event = ftrace_find_event(entry->type);
2597 enum print_line_t ret = event->funcs->hex(iter, 0, event);
2598 if (ret != TRACE_TYPE_HANDLED)
2602 SEQ_PUT_FIELD_RET(s, newline);
2604 return TRACE_TYPE_HANDLED;
2607 static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
2609 struct trace_seq *s = &iter->seq;
2610 struct trace_entry *entry;
2611 struct trace_event *event;
2615 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
2616 SEQ_PUT_FIELD_RET(s, entry->pid);
2617 SEQ_PUT_FIELD_RET(s, iter->cpu);
2618 SEQ_PUT_FIELD_RET(s, iter->ts);
2621 event = ftrace_find_event(entry->type);
2622 return event ? event->funcs->binary(iter, 0, event) :
2626 int trace_empty(struct trace_iterator *iter)
2628 struct ring_buffer_iter *buf_iter;
2631 /* If we are looking at one CPU buffer, only check that one */
2632 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
2633 cpu = iter->cpu_file;
2634 buf_iter = trace_buffer_iter(iter, cpu);
2636 if (!ring_buffer_iter_empty(buf_iter))
2639 if (!ring_buffer_empty_cpu(iter->trace_buffer->buffer, cpu))
2645 for_each_tracing_cpu(cpu) {
2646 buf_iter = trace_buffer_iter(iter, cpu);
2648 if (!ring_buffer_iter_empty(buf_iter))
2651 if (!ring_buffer_empty_cpu(iter->trace_buffer->buffer, cpu))
2659 /* Called with trace_event_read_lock() held. */
2660 enum print_line_t print_trace_line(struct trace_iterator *iter)
2662 enum print_line_t ret;
2664 if (iter->lost_events &&
2665 !trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
2666 iter->cpu, iter->lost_events))
2667 return TRACE_TYPE_PARTIAL_LINE;
2669 if (iter->trace && iter->trace->print_line) {
2670 ret = iter->trace->print_line(iter);
2671 if (ret != TRACE_TYPE_UNHANDLED)
2675 if (iter->ent->type == TRACE_BPUTS &&
2676 trace_flags & TRACE_ITER_PRINTK &&
2677 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
2678 return trace_print_bputs_msg_only(iter);
2680 if (iter->ent->type == TRACE_BPRINT &&
2681 trace_flags & TRACE_ITER_PRINTK &&
2682 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
2683 return trace_print_bprintk_msg_only(iter);
2685 if (iter->ent->type == TRACE_PRINT &&
2686 trace_flags & TRACE_ITER_PRINTK &&
2687 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
2688 return trace_print_printk_msg_only(iter);
2690 if (trace_flags & TRACE_ITER_BIN)
2691 return print_bin_fmt(iter);
2693 if (trace_flags & TRACE_ITER_HEX)
2694 return print_hex_fmt(iter);
2696 if (trace_flags & TRACE_ITER_RAW)
2697 return print_raw_fmt(iter);
2699 return print_trace_fmt(iter);
2702 void trace_latency_header(struct seq_file *m)
2704 struct trace_iterator *iter = m->private;
2706 /* print nothing if the buffers are empty */
2707 if (trace_empty(iter))
2710 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
2711 print_trace_header(m, iter);
2713 if (!(trace_flags & TRACE_ITER_VERBOSE))
2714 print_lat_help_header(m);
2717 void trace_default_header(struct seq_file *m)
2719 struct trace_iterator *iter = m->private;
2721 if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
2724 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
2725 /* print nothing if the buffers are empty */
2726 if (trace_empty(iter))
2728 print_trace_header(m, iter);
2729 if (!(trace_flags & TRACE_ITER_VERBOSE))
2730 print_lat_help_header(m);
2732 if (!(trace_flags & TRACE_ITER_VERBOSE)) {
2733 if (trace_flags & TRACE_ITER_IRQ_INFO)
2734 print_func_help_header_irq(iter->trace_buffer, m);
2736 print_func_help_header(iter->trace_buffer, m);
2741 static void test_ftrace_alive(struct seq_file *m)
2743 if (!ftrace_is_dead())
2745 seq_printf(m, "# WARNING: FUNCTION TRACING IS CORRUPTED\n");
2746 seq_printf(m, "# MAY BE MISSING FUNCTION EVENTS\n");
2749 #ifdef CONFIG_TRACER_MAX_TRACE
2750 static void show_snapshot_main_help(struct seq_file *m)
2752 seq_printf(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n");
2753 seq_printf(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n");
2754 seq_printf(m, "# Takes a snapshot of the main buffer.\n");
2755 seq_printf(m, "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate)\n");
2756 seq_printf(m, "# (Doesn't have to be '2' works with any number that\n");
2757 seq_printf(m, "# is not a '0' or '1')\n");
2760 static void show_snapshot_percpu_help(struct seq_file *m)
2762 seq_printf(m, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n");
2763 #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
2764 seq_printf(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n");
2765 seq_printf(m, "# Takes a snapshot of the main buffer for this cpu.\n");
2767 seq_printf(m, "# echo 1 > snapshot : Not supported with this kernel.\n");
2768 seq_printf(m, "# Must use main snapshot file to allocate.\n");
2770 seq_printf(m, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n");
2771 seq_printf(m, "# (Doesn't have to be '2' works with any number that\n");
2772 seq_printf(m, "# is not a '0' or '1')\n");
2775 static void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter)
2777 if (iter->tr->allocated_snapshot)
2778 seq_printf(m, "#\n# * Snapshot is allocated *\n#\n");
2780 seq_printf(m, "#\n# * Snapshot is freed *\n#\n");
2782 seq_printf(m, "# Snapshot commands:\n");
2783 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
2784 show_snapshot_main_help(m);
2786 show_snapshot_percpu_help(m);
2789 /* Should never be called */
2790 static inline void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter) { }
2793 static int s_show(struct seq_file *m, void *v)
2795 struct trace_iterator *iter = v;
2798 if (iter->ent == NULL) {
2800 seq_printf(m, "# tracer: %s\n", iter->trace->name);
2802 test_ftrace_alive(m);
2804 if (iter->snapshot && trace_empty(iter))
2805 print_snapshot_help(m, iter);
2806 else if (iter->trace && iter->trace->print_header)
2807 iter->trace->print_header(m);
2809 trace_default_header(m);
2811 } else if (iter->leftover) {
2813 * If we filled the seq_file buffer earlier, we
2814 * want to just show it now.
2816 ret = trace_print_seq(m, &iter->seq);
2818 /* ret should this time be zero, but you never know */
2819 iter->leftover = ret;
2822 print_trace_line(iter);
2823 ret = trace_print_seq(m, &iter->seq);
2825 * If we overflow the seq_file buffer, then it will
2826 * ask us for this data again at start up.
2828 * ret is 0 if seq_file write succeeded.
2831 iter->leftover = ret;
2837 static const struct seq_operations tracer_seq_ops = {
2844 static struct trace_iterator *
2845 __tracing_open(struct trace_array *tr, struct trace_cpu *tc,
2846 struct inode *inode, struct file *file, bool snapshot)
2848 struct trace_iterator *iter;
2851 if (tracing_disabled)
2852 return ERR_PTR(-ENODEV);
2854 iter = __seq_open_private(file, &tracer_seq_ops, sizeof(*iter));
2856 return ERR_PTR(-ENOMEM);
2858 iter->buffer_iter = kzalloc(sizeof(*iter->buffer_iter) * num_possible_cpus(),
2860 if (!iter->buffer_iter)
2864 * We make a copy of the current tracer to avoid concurrent
2865 * changes on it while we are reading.
2867 mutex_lock(&trace_types_lock);
2868 iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL);
2872 *iter->trace = *tr->current_trace;
2874 if (!zalloc_cpumask_var(&iter->started, GFP_KERNEL))
2879 #ifdef CONFIG_TRACER_MAX_TRACE
2880 /* Currently only the top directory has a snapshot */
2881 if (tr->current_trace->print_max || snapshot)
2882 iter->trace_buffer = &tr->max_buffer;
2885 iter->trace_buffer = &tr->trace_buffer;
2886 iter->snapshot = snapshot;
2888 mutex_init(&iter->mutex);
2889 iter->cpu_file = tc->cpu;
2891 /* Notify the tracer early; before we stop tracing. */
2892 if (iter->trace && iter->trace->open)
2893 iter->trace->open(iter);
2895 /* Annotate start of buffers if we had overruns */
2896 if (ring_buffer_overruns(iter->trace_buffer->buffer))
2897 iter->iter_flags |= TRACE_FILE_ANNOTATE;
2899 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
2900 if (trace_clocks[tr->clock_id].in_ns)
2901 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
2903 /* stop the trace while dumping if we are not opening "snapshot" */
2904 if (!iter->snapshot)
2905 tracing_stop_tr(tr);
2907 if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
2908 for_each_tracing_cpu(cpu) {
2909 iter->buffer_iter[cpu] =
2910 ring_buffer_read_prepare(iter->trace_buffer->buffer, cpu);
2912 ring_buffer_read_prepare_sync();
2913 for_each_tracing_cpu(cpu) {
2914 ring_buffer_read_start(iter->buffer_iter[cpu]);
2915 tracing_iter_reset(iter, cpu);
2918 cpu = iter->cpu_file;
2919 iter->buffer_iter[cpu] =
2920 ring_buffer_read_prepare(iter->trace_buffer->buffer, cpu);
2921 ring_buffer_read_prepare_sync();
2922 ring_buffer_read_start(iter->buffer_iter[cpu]);
2923 tracing_iter_reset(iter, cpu);
2926 mutex_unlock(&trace_types_lock);
2931 mutex_unlock(&trace_types_lock);
2933 kfree(iter->buffer_iter);
2935 seq_release_private(inode, file);
2936 return ERR_PTR(-ENOMEM);
2939 int tracing_open_generic(struct inode *inode, struct file *filp)
2941 if (tracing_disabled)
2944 filp->private_data = inode->i_private;
2949 * Open and update trace_array ref count.
2950 * Must have the current trace_array passed to it.
2952 int tracing_open_generic_tr(struct inode *inode, struct file *filp)
2954 struct trace_array *tr = inode->i_private;
2956 if (tracing_disabled)
2959 if (trace_array_get(tr) < 0)
2962 filp->private_data = inode->i_private;
2968 int tracing_open_generic_tc(struct inode *inode, struct file *filp)
2970 struct trace_cpu *tc = inode->i_private;
2971 struct trace_array *tr = tc->tr;
2973 if (tracing_disabled)
2976 if (trace_array_get(tr) < 0)
2979 filp->private_data = inode->i_private;
2985 static int tracing_release(struct inode *inode, struct file *file)
2987 struct seq_file *m = file->private_data;
2988 struct trace_iterator *iter;
2989 struct trace_array *tr;
2992 /* Writes do not use seq_file, need to grab tr from inode */
2993 if (!(file->f_mode & FMODE_READ)) {
2994 struct trace_cpu *tc = inode->i_private;
2996 trace_array_put(tc->tr);
3003 mutex_lock(&trace_types_lock);
3005 for_each_tracing_cpu(cpu) {
3006 if (iter->buffer_iter[cpu])
3007 ring_buffer_read_finish(iter->buffer_iter[cpu]);
3010 if (iter->trace && iter->trace->close)
3011 iter->trace->close(iter);
3013 if (!iter->snapshot)
3014 /* reenable tracing if it was previously enabled */
3015 tracing_start_tr(tr);
3017 __trace_array_put(tr);
3019 mutex_unlock(&trace_types_lock);
3021 mutex_destroy(&iter->mutex);
3022 free_cpumask_var(iter->started);
3024 kfree(iter->buffer_iter);
3025 seq_release_private(inode, file);
3030 static int tracing_release_generic_tr(struct inode *inode, struct file *file)
3032 struct trace_array *tr = inode->i_private;
3034 trace_array_put(tr);
3038 static int tracing_release_generic_tc(struct inode *inode, struct file *file)
3040 struct trace_cpu *tc = inode->i_private;
3041 struct trace_array *tr = tc->tr;
3043 trace_array_put(tr);
3047 static int tracing_single_release_tr(struct inode *inode, struct file *file)
3049 struct trace_array *tr = inode->i_private;
3051 trace_array_put(tr);
3053 return single_release(inode, file);
3056 static int tracing_open(struct inode *inode, struct file *file)
3058 struct trace_cpu *tc = inode->i_private;
3059 struct trace_array *tr = tc->tr;
3060 struct trace_iterator *iter;
3063 if (trace_array_get(tr) < 0)
3066 /* If this file was open for write, then erase contents */
3067 if ((file->f_mode & FMODE_WRITE) &&
3068 (file->f_flags & O_TRUNC)) {
3069 if (tc->cpu == RING_BUFFER_ALL_CPUS)
3070 tracing_reset_online_cpus(&tr->trace_buffer);
3072 tracing_reset(&tr->trace_buffer, tc->cpu);
3075 if (file->f_mode & FMODE_READ) {
3076 iter = __tracing_open(tr, tc, inode, file, false);
3078 ret = PTR_ERR(iter);
3079 else if (trace_flags & TRACE_ITER_LATENCY_FMT)
3080 iter->iter_flags |= TRACE_FILE_LAT_FMT;
3084 trace_array_put(tr);
3090 t_next(struct seq_file *m, void *v, loff_t *pos)
3092 struct tracer *t = v;
3102 static void *t_start(struct seq_file *m, loff_t *pos)
3107 mutex_lock(&trace_types_lock);
3108 for (t = trace_types; t && l < *pos; t = t_next(m, t, &l))
3114 static void t_stop(struct seq_file *m, void *p)
3116 mutex_unlock(&trace_types_lock);
3119 static int t_show(struct seq_file *m, void *v)
3121 struct tracer *t = v;
3126 seq_printf(m, "%s", t->name);
3135 static const struct seq_operations show_traces_seq_ops = {
3142 static int show_traces_open(struct inode *inode, struct file *file)
3144 if (tracing_disabled)
3147 return seq_open(file, &show_traces_seq_ops);
3151 tracing_write_stub(struct file *filp, const char __user *ubuf,
3152 size_t count, loff_t *ppos)
3157 static loff_t tracing_seek(struct file *file, loff_t offset, int origin)
3159 if (file->f_mode & FMODE_READ)
3160 return seq_lseek(file, offset, origin);
3165 static const struct file_operations tracing_fops = {
3166 .open = tracing_open,
3168 .write = tracing_write_stub,
3169 .llseek = tracing_seek,
3170 .release = tracing_release,
3173 static const struct file_operations show_traces_fops = {
3174 .open = show_traces_open,
3176 .release = seq_release,
3177 .llseek = seq_lseek,
3181 * Only trace on a CPU if the bitmask is set:
3183 static cpumask_var_t tracing_cpumask;
3186 * The tracer itself will not take this lock, but still we want
3187 * to provide a consistent cpumask to user-space:
3189 static DEFINE_MUTEX(tracing_cpumask_update_lock);
3192 * Temporary storage for the character representation of the
3193 * CPU bitmask (and one more byte for the newline):
3195 static char mask_str[NR_CPUS + 1];
3198 tracing_cpumask_read(struct file *filp, char __user *ubuf,
3199 size_t count, loff_t *ppos)
3203 mutex_lock(&tracing_cpumask_update_lock);
3205 len = cpumask_scnprintf(mask_str, count, tracing_cpumask);
3206 if (count - len < 2) {
3210 len += sprintf(mask_str + len, "\n");
3211 count = simple_read_from_buffer(ubuf, count, ppos, mask_str, NR_CPUS+1);
3214 mutex_unlock(&tracing_cpumask_update_lock);
3220 tracing_cpumask_write(struct file *filp, const char __user *ubuf,
3221 size_t count, loff_t *ppos)
3223 struct trace_array *tr = filp->private_data;
3224 cpumask_var_t tracing_cpumask_new;
3227 if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
3230 err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
3234 mutex_lock(&tracing_cpumask_update_lock);
3236 local_irq_disable();
3237 arch_spin_lock(&ftrace_max_lock);
3238 for_each_tracing_cpu(cpu) {
3240 * Increase/decrease the disabled counter if we are
3241 * about to flip a bit in the cpumask:
3243 if (cpumask_test_cpu(cpu, tracing_cpumask) &&
3244 !cpumask_test_cpu(cpu, tracing_cpumask_new)) {
3245 atomic_inc(&per_cpu_ptr(tr->trace_buffer.data, cpu)->disabled);
3246 ring_buffer_record_disable_cpu(tr->trace_buffer.buffer, cpu);
3248 if (!cpumask_test_cpu(cpu, tracing_cpumask) &&
3249 cpumask_test_cpu(cpu, tracing_cpumask_new)) {
3250 atomic_dec(&per_cpu_ptr(tr->trace_buffer.data, cpu)->disabled);
3251 ring_buffer_record_enable_cpu(tr->trace_buffer.buffer, cpu);
3254 arch_spin_unlock(&ftrace_max_lock);
3257 cpumask_copy(tracing_cpumask, tracing_cpumask_new);
3259 mutex_unlock(&tracing_cpumask_update_lock);
3260 free_cpumask_var(tracing_cpumask_new);
3265 free_cpumask_var(tracing_cpumask_new);
3270 static const struct file_operations tracing_cpumask_fops = {
3271 .open = tracing_open_generic,
3272 .read = tracing_cpumask_read,
3273 .write = tracing_cpumask_write,
3274 .llseek = generic_file_llseek,
3277 static int tracing_trace_options_show(struct seq_file *m, void *v)
3279 struct tracer_opt *trace_opts;
3280 struct trace_array *tr = m->private;
3284 mutex_lock(&trace_types_lock);
3285 tracer_flags = tr->current_trace->flags->val;
3286 trace_opts = tr->current_trace->flags->opts;
3288 for (i = 0; trace_options[i]; i++) {
3289 if (trace_flags & (1 << i))
3290 seq_printf(m, "%s\n", trace_options[i]);
3292 seq_printf(m, "no%s\n", trace_options[i]);
3295 for (i = 0; trace_opts[i].name; i++) {
3296 if (tracer_flags & trace_opts[i].bit)
3297 seq_printf(m, "%s\n", trace_opts[i].name);
3299 seq_printf(m, "no%s\n", trace_opts[i].name);
3301 mutex_unlock(&trace_types_lock);
3306 static int __set_tracer_option(struct tracer *trace,
3307 struct tracer_flags *tracer_flags,
3308 struct tracer_opt *opts, int neg)
3312 ret = trace->set_flag(tracer_flags->val, opts->bit, !neg);
3317 tracer_flags->val &= ~opts->bit;
3319 tracer_flags->val |= opts->bit;
3323 /* Try to assign a tracer specific option */
3324 static int set_tracer_option(struct tracer *trace, char *cmp, int neg)
3326 struct tracer_flags *tracer_flags = trace->flags;
3327 struct tracer_opt *opts = NULL;
3330 for (i = 0; tracer_flags->opts[i].name; i++) {
3331 opts = &tracer_flags->opts[i];
3333 if (strcmp(cmp, opts->name) == 0)
3334 return __set_tracer_option(trace, trace->flags,
3341 /* Some tracers require overwrite to stay enabled */
3342 int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set)
3344 if (tracer->enabled && (mask & TRACE_ITER_OVERWRITE) && !set)
3350 int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled)
3352 /* do nothing if flag is already set */
3353 if (!!(trace_flags & mask) == !!enabled)
3356 /* Give the tracer a chance to approve the change */
3357 if (tr->current_trace->flag_changed)
3358 if (tr->current_trace->flag_changed(tr->current_trace, mask, !!enabled))
3362 trace_flags |= mask;
3364 trace_flags &= ~mask;
3366 if (mask == TRACE_ITER_RECORD_CMD)
3367 trace_event_enable_cmd_record(enabled);
3369 if (mask == TRACE_ITER_OVERWRITE) {
3370 ring_buffer_change_overwrite(tr->trace_buffer.buffer, enabled);
3371 #ifdef CONFIG_TRACER_MAX_TRACE
3372 ring_buffer_change_overwrite(tr->max_buffer.buffer, enabled);
3376 if (mask == TRACE_ITER_PRINTK)
3377 trace_printk_start_stop_comm(enabled);
3382 static int trace_set_options(struct trace_array *tr, char *option)
3389 cmp = strstrip(option);
3391 if (strncmp(cmp, "no", 2) == 0) {
3396 mutex_lock(&trace_types_lock);
3398 for (i = 0; trace_options[i]; i++) {
3399 if (strcmp(cmp, trace_options[i]) == 0) {
3400 ret = set_tracer_flag(tr, 1 << i, !neg);
3405 /* If no option could be set, test the specific tracer options */
3406 if (!trace_options[i])
3407 ret = set_tracer_option(tr->current_trace, cmp, neg);
3409 mutex_unlock(&trace_types_lock);
3415 tracing_trace_options_write(struct file *filp, const char __user *ubuf,
3416 size_t cnt, loff_t *ppos)
3418 struct seq_file *m = filp->private_data;
3419 struct trace_array *tr = m->private;
3423 if (cnt >= sizeof(buf))
3426 if (copy_from_user(&buf, ubuf, cnt))
3431 ret = trace_set_options(tr, buf);
3440 static int tracing_trace_options_open(struct inode *inode, struct file *file)
3442 struct trace_array *tr = inode->i_private;
3445 if (tracing_disabled)
3448 if (trace_array_get(tr) < 0)
3451 ret = single_open(file, tracing_trace_options_show, inode->i_private);
3453 trace_array_put(tr);
3458 static const struct file_operations tracing_iter_fops = {
3459 .open = tracing_trace_options_open,
3461 .llseek = seq_lseek,
3462 .release = tracing_single_release_tr,
3463 .write = tracing_trace_options_write,
3466 static const char readme_msg[] =
3467 "tracing mini-HOWTO:\n\n"
3468 "# echo 0 > tracing_on : quick way to disable tracing\n"
3469 "# echo 1 > tracing_on : quick way to re-enable tracing\n\n"
3470 " Important files:\n"
3471 " trace\t\t\t- The static contents of the buffer\n"
3472 "\t\t\t To clear the buffer write into this file: echo > trace\n"
3473 " trace_pipe\t\t- A consuming read to see the contents of the buffer\n"
3474 " current_tracer\t- function and latency tracers\n"
3475 " available_tracers\t- list of configured tracers for current_tracer\n"
3476 " buffer_size_kb\t- view and modify size of per cpu buffer\n"
3477 " buffer_total_size_kb - view total size of all cpu buffers\n\n"
3478 " trace_clock\t\t-change the clock used to order events\n"
3479 " local: Per cpu clock but may not be synced across CPUs\n"
3480 " global: Synced across CPUs but slows tracing down.\n"
3481 " counter: Not a clock, but just an increment\n"
3482 " uptime: Jiffy counter from time of boot\n"
3483 " perf: Same clock that perf events use\n"
3484 #ifdef CONFIG_X86_64
3485 " x86-tsc: TSC cycle counter\n"
3487 "\n trace_marker\t\t- Writes into this file writes into the kernel buffer\n"
3488 " tracing_cpumask\t- Limit which CPUs to trace\n"
3489 " instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
3490 "\t\t\t Remove sub-buffer with rmdir\n"
3491 " trace_options\t\t- Set format or modify how tracing happens\n"
3492 "\t\t\t Disable an option by adding a suffix 'no' to the option name\n"
3493 #ifdef CONFIG_DYNAMIC_FTRACE
3494 "\n available_filter_functions - list of functions that can be filtered on\n"
3495 " set_ftrace_filter\t- echo function name in here to only trace these functions\n"
3496 " accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
3497 " modules: Can select a group via module\n"
3498 " Format: :mod:<module-name>\n"
3499 " example: echo :mod:ext3 > set_ftrace_filter\n"
3500 " triggers: a command to perform when function is hit\n"
3501 " Format: <function>:<trigger>[:count]\n"
3502 " trigger: traceon, traceoff\n"
3503 " enable_event:<system>:<event>\n"
3504 " disable_event:<system>:<event>\n"
3505 #ifdef CONFIG_STACKTRACE
3508 #ifdef CONFIG_TRACER_SNAPSHOT
3511 " example: echo do_fault:traceoff > set_ftrace_filter\n"
3512 " echo do_trap:traceoff:3 > set_ftrace_filter\n"
3513 " The first one will disable tracing every time do_fault is hit\n"
3514 " The second will disable tracing at most 3 times when do_trap is hit\n"
3515 " The first time do trap is hit and it disables tracing, the counter\n"
3516 " will decrement to 2. If tracing is already disabled, the counter\n"
3517 " will not decrement. It only decrements when the trigger did work\n"
3518 " To remove trigger without count:\n"
3519 " echo '!<function>:<trigger> > set_ftrace_filter\n"
3520 " To remove trigger with a count:\n"
3521 " echo '!<function>:<trigger>:0 > set_ftrace_filter\n"
3522 " set_ftrace_notrace\t- echo function name in here to never trace.\n"
3523 " accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
3524 " modules: Can select a group via module command :mod:\n"
3525 " Does not accept triggers\n"
3526 #endif /* CONFIG_DYNAMIC_FTRACE */
3527 #ifdef CONFIG_FUNCTION_TRACER
3528 " set_ftrace_pid\t- Write pid(s) to only function trace those pids (function)\n"
3530 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
3531 " set_graph_function\t- Trace the nested calls of a function (function_graph)\n"
3532 " max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n"
3534 #ifdef CONFIG_TRACER_SNAPSHOT
3535 "\n snapshot\t\t- Like 'trace' but shows the content of the static snapshot buffer\n"
3536 "\t\t\t Read the contents for more information\n"
3538 #ifdef CONFIG_STACKTRACE
3539 " stack_trace\t\t- Shows the max stack trace when active\n"
3540 " stack_max_size\t- Shows current max stack size that was traced\n"
3541 "\t\t\t Write into this file to reset the max size (trigger a new trace)\n"
3542 #ifdef CONFIG_DYNAMIC_FTRACE
3543 " stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace traces\n"
3545 #endif /* CONFIG_STACKTRACE */
3549 tracing_readme_read(struct file *filp, char __user *ubuf,
3550 size_t cnt, loff_t *ppos)
3552 return simple_read_from_buffer(ubuf, cnt, ppos,
3553 readme_msg, strlen(readme_msg));
3556 static const struct file_operations tracing_readme_fops = {
3557 .open = tracing_open_generic,
3558 .read = tracing_readme_read,
3559 .llseek = generic_file_llseek,
3563 tracing_saved_cmdlines_read(struct file *file, char __user *ubuf,
3564 size_t cnt, loff_t *ppos)
3573 file_buf = kmalloc(SAVED_CMDLINES*(16+TASK_COMM_LEN), GFP_KERNEL);
3577 buf_comm = kmalloc(TASK_COMM_LEN, GFP_KERNEL);
3585 for (i = 0; i < SAVED_CMDLINES; i++) {
3588 pid = map_cmdline_to_pid[i];
3589 if (pid == -1 || pid == NO_CMDLINE_MAP)
3592 trace_find_cmdline(pid, buf_comm);
3593 r = sprintf(buf, "%d %s\n", pid, buf_comm);
3598 len = simple_read_from_buffer(ubuf, cnt, ppos,
3607 static const struct file_operations tracing_saved_cmdlines_fops = {
3608 .open = tracing_open_generic,
3609 .read = tracing_saved_cmdlines_read,
3610 .llseek = generic_file_llseek,
3614 tracing_set_trace_read(struct file *filp, char __user *ubuf,
3615 size_t cnt, loff_t *ppos)
3617 struct trace_array *tr = filp->private_data;
3618 char buf[MAX_TRACER_SIZE+2];
3621 mutex_lock(&trace_types_lock);
3622 r = sprintf(buf, "%s\n", tr->current_trace->name);
3623 mutex_unlock(&trace_types_lock);
3625 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
3628 int tracer_init(struct tracer *t, struct trace_array *tr)
3630 tracing_reset_online_cpus(&tr->trace_buffer);
3634 static void set_buffer_entries(struct trace_buffer *buf, unsigned long val)
3638 for_each_tracing_cpu(cpu)
3639 per_cpu_ptr(buf->data, cpu)->entries = val;
3642 #ifdef CONFIG_TRACER_MAX_TRACE
3643 /* resize @tr's buffer to the size of @size_tr's entries */
3644 static int resize_buffer_duplicate_size(struct trace_buffer *trace_buf,
3645 struct trace_buffer *size_buf, int cpu_id)
3649 if (cpu_id == RING_BUFFER_ALL_CPUS) {
3650 for_each_tracing_cpu(cpu) {
3651 ret = ring_buffer_resize(trace_buf->buffer,
3652 per_cpu_ptr(size_buf->data, cpu)->entries, cpu);
3655 per_cpu_ptr(trace_buf->data, cpu)->entries =
3656 per_cpu_ptr(size_buf->data, cpu)->entries;
3659 ret = ring_buffer_resize(trace_buf->buffer,
3660 per_cpu_ptr(size_buf->data, cpu_id)->entries, cpu_id);
3662 per_cpu_ptr(trace_buf->data, cpu_id)->entries =
3663 per_cpu_ptr(size_buf->data, cpu_id)->entries;
3668 #endif /* CONFIG_TRACER_MAX_TRACE */
3670 static int __tracing_resize_ring_buffer(struct trace_array *tr,
3671 unsigned long size, int cpu)
3676 * If kernel or user changes the size of the ring buffer
3677 * we use the size that was given, and we can forget about
3678 * expanding it later.
3680 ring_buffer_expanded = true;
3682 /* May be called before buffers are initialized */
3683 if (!tr->trace_buffer.buffer)
3686 ret = ring_buffer_resize(tr->trace_buffer.buffer, size, cpu);
3690 #ifdef CONFIG_TRACER_MAX_TRACE
3691 if (!(tr->flags & TRACE_ARRAY_FL_GLOBAL) ||
3692 !tr->current_trace->use_max_tr)
3695 ret = ring_buffer_resize(tr->max_buffer.buffer, size, cpu);
3697 int r = resize_buffer_duplicate_size(&tr->trace_buffer,
3698 &tr->trace_buffer, cpu);
3701 * AARGH! We are left with different
3702 * size max buffer!!!!
3703 * The max buffer is our "snapshot" buffer.
3704 * When a tracer needs a snapshot (one of the
3705 * latency tracers), it swaps the max buffer
3706 * with the saved snap shot. We succeeded to
3707 * update the size of the main buffer, but failed to
3708 * update the size of the max buffer. But when we tried
3709 * to reset the main buffer to the original size, we
3710 * failed there too. This is very unlikely to
3711 * happen, but if it does, warn and kill all
3715 tracing_disabled = 1;
3720 if (cpu == RING_BUFFER_ALL_CPUS)
3721 set_buffer_entries(&tr->max_buffer, size);
3723 per_cpu_ptr(tr->max_buffer.data, cpu)->entries = size;
3726 #endif /* CONFIG_TRACER_MAX_TRACE */
3728 if (cpu == RING_BUFFER_ALL_CPUS)
3729 set_buffer_entries(&tr->trace_buffer, size);
3731 per_cpu_ptr(tr->trace_buffer.data, cpu)->entries = size;
3736 static ssize_t tracing_resize_ring_buffer(struct trace_array *tr,
3737 unsigned long size, int cpu_id)
3741 mutex_lock(&trace_types_lock);
3743 if (cpu_id != RING_BUFFER_ALL_CPUS) {
3744 /* make sure, this cpu is enabled in the mask */
3745 if (!cpumask_test_cpu(cpu_id, tracing_buffer_mask)) {
3751 ret = __tracing_resize_ring_buffer(tr, size, cpu_id);
3756 mutex_unlock(&trace_types_lock);
3763 * tracing_update_buffers - used by tracing facility to expand ring buffers
3765 * To save on memory when the tracing is never used on a system with it
3766 * configured in. The ring buffers are set to a minimum size. But once
3767 * a user starts to use the tracing facility, then they need to grow
3768 * to their default size.
3770 * This function is to be called when a tracer is about to be used.
3772 int tracing_update_buffers(void)
3776 mutex_lock(&trace_types_lock);
3777 if (!ring_buffer_expanded)
3778 ret = __tracing_resize_ring_buffer(&global_trace, trace_buf_size,
3779 RING_BUFFER_ALL_CPUS);
3780 mutex_unlock(&trace_types_lock);
3785 struct trace_option_dentry;
3787 static struct trace_option_dentry *
3788 create_trace_option_files(struct trace_array *tr, struct tracer *tracer);
3791 destroy_trace_option_files(struct trace_option_dentry *topts);
3793 static int tracing_set_tracer(const char *buf)
3795 static struct trace_option_dentry *topts;
3796 struct trace_array *tr = &global_trace;
3798 #ifdef CONFIG_TRACER_MAX_TRACE
3803 mutex_lock(&trace_types_lock);
3805 if (!ring_buffer_expanded) {
3806 ret = __tracing_resize_ring_buffer(tr, trace_buf_size,
3807 RING_BUFFER_ALL_CPUS);
3813 for (t = trace_types; t; t = t->next) {
3814 if (strcmp(t->name, buf) == 0)
3821 if (t == tr->current_trace)
3824 trace_branch_disable();
3826 tr->current_trace->enabled = false;
3828 if (tr->current_trace->reset)
3829 tr->current_trace->reset(tr);
3831 /* Current trace needs to be nop_trace before synchronize_sched */
3832 tr->current_trace = &nop_trace;
3834 #ifdef CONFIG_TRACER_MAX_TRACE
3835 had_max_tr = tr->allocated_snapshot;
3837 if (had_max_tr && !t->use_max_tr) {
3839 * We need to make sure that the update_max_tr sees that
3840 * current_trace changed to nop_trace to keep it from
3841 * swapping the buffers after we resize it.
3842 * The update_max_tr is called from interrupts disabled
3843 * so a synchronized_sched() is sufficient.
3845 synchronize_sched();
3849 destroy_trace_option_files(topts);
3851 topts = create_trace_option_files(tr, t);
3853 #ifdef CONFIG_TRACER_MAX_TRACE
3854 if (t->use_max_tr && !had_max_tr) {
3855 ret = alloc_snapshot(tr);
3862 ret = tracer_init(t, tr);
3867 tr->current_trace = t;
3868 tr->current_trace->enabled = true;
3869 trace_branch_enable(tr);
3871 mutex_unlock(&trace_types_lock);
3877 tracing_set_trace_write(struct file *filp, const char __user *ubuf,
3878 size_t cnt, loff_t *ppos)
3880 char buf[MAX_TRACER_SIZE+1];
3887 if (cnt > MAX_TRACER_SIZE)
3888 cnt = MAX_TRACER_SIZE;
3890 if (copy_from_user(&buf, ubuf, cnt))
3895 /* strip ending whitespace. */
3896 for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
3899 err = tracing_set_tracer(buf);
3909 tracing_max_lat_read(struct file *filp, char __user *ubuf,
3910 size_t cnt, loff_t *ppos)
3912 unsigned long *ptr = filp->private_data;
3916 r = snprintf(buf, sizeof(buf), "%ld\n",
3917 *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
3918 if (r > sizeof(buf))
3920 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
3924 tracing_max_lat_write(struct file *filp, const char __user *ubuf,
3925 size_t cnt, loff_t *ppos)
3927 unsigned long *ptr = filp->private_data;
3931 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
3940 static int tracing_open_pipe(struct inode *inode, struct file *filp)
3942 struct trace_cpu *tc = inode->i_private;
3943 struct trace_array *tr = tc->tr;
3944 struct trace_iterator *iter;
3947 if (tracing_disabled)
3950 if (trace_array_get(tr) < 0)
3953 mutex_lock(&trace_types_lock);
3955 /* create a buffer to store the information to pass to userspace */
3956 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3959 __trace_array_put(tr);
3964 * We make a copy of the current tracer to avoid concurrent
3965 * changes on it while we are reading.
3967 iter->trace = kmalloc(sizeof(*iter->trace), GFP_KERNEL);
3972 *iter->trace = *tr->current_trace;
3974 if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
3979 /* trace pipe does not show start of buffer */
3980 cpumask_setall(iter->started);
3982 if (trace_flags & TRACE_ITER_LATENCY_FMT)
3983 iter->iter_flags |= TRACE_FILE_LAT_FMT;
3985 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
3986 if (trace_clocks[tr->clock_id].in_ns)
3987 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
3989 iter->cpu_file = tc->cpu;
3991 iter->trace_buffer = &tc->tr->trace_buffer;
3992 mutex_init(&iter->mutex);
3993 filp->private_data = iter;
3995 if (iter->trace->pipe_open)
3996 iter->trace->pipe_open(iter);
3998 nonseekable_open(inode, filp);
4000 mutex_unlock(&trace_types_lock);
4006 __trace_array_put(tr);
4007 mutex_unlock(&trace_types_lock);
4011 static int tracing_release_pipe(struct inode *inode, struct file *file)
4013 struct trace_iterator *iter = file->private_data;
4014 struct trace_cpu *tc = inode->i_private;
4015 struct trace_array *tr = tc->tr;
4017 mutex_lock(&trace_types_lock);
4019 if (iter->trace->pipe_close)
4020 iter->trace->pipe_close(iter);
4022 mutex_unlock(&trace_types_lock);
4024 free_cpumask_var(iter->started);
4025 mutex_destroy(&iter->mutex);
4029 trace_array_put(tr);
4035 trace_poll(struct trace_iterator *iter, struct file *filp, poll_table *poll_table)
4037 /* Iterators are static, they should be filled or empty */
4038 if (trace_buffer_iter(iter, iter->cpu_file))
4039 return POLLIN | POLLRDNORM;
4041 if (trace_flags & TRACE_ITER_BLOCK)
4043 * Always select as readable when in blocking mode
4045 return POLLIN | POLLRDNORM;
4047 return ring_buffer_poll_wait(iter->trace_buffer->buffer, iter->cpu_file,
4052 tracing_poll_pipe(struct file *filp, poll_table *poll_table)
4054 struct trace_iterator *iter = filp->private_data;
4056 return trace_poll(iter, filp, poll_table);
4060 * This is a make-shift waitqueue.
4061 * A tracer might use this callback on some rare cases:
4063 * 1) the current tracer might hold the runqueue lock when it wakes up
4064 * a reader, hence a deadlock (sched, function, and function graph tracers)
4065 * 2) the function tracers, trace all functions, we don't want
4066 * the overhead of calling wake_up and friends
4067 * (and tracing them too)
4069 * Anyway, this is really very primitive wakeup.
4071 void poll_wait_pipe(struct trace_iterator *iter)
4073 set_current_state(TASK_INTERRUPTIBLE);
4074 /* sleep for 100 msecs, and try again. */
4075 schedule_timeout(HZ / 10);
4078 /* Must be called with trace_types_lock mutex held. */
4079 static int tracing_wait_pipe(struct file *filp)
4081 struct trace_iterator *iter = filp->private_data;
4083 while (trace_empty(iter)) {
4085 if ((filp->f_flags & O_NONBLOCK)) {
4089 mutex_unlock(&iter->mutex);
4091 iter->trace->wait_pipe(iter);
4093 mutex_lock(&iter->mutex);
4095 if (signal_pending(current))
4099 * We block until we read something and tracing is disabled.
4100 * We still block if tracing is disabled, but we have never
4101 * read anything. This allows a user to cat this file, and
4102 * then enable tracing. But after we have read something,
4103 * we give an EOF when tracing is again disabled.
4105 * iter->pos will be 0 if we haven't read anything.
4107 if (!tracing_is_on() && iter->pos)
4118 tracing_read_pipe(struct file *filp, char __user *ubuf,
4119 size_t cnt, loff_t *ppos)
4121 struct trace_iterator *iter = filp->private_data;
4122 struct trace_array *tr = iter->tr;
4125 /* return any leftover data */
4126 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
4130 trace_seq_init(&iter->seq);
4132 /* copy the tracer to avoid using a global lock all around */
4133 mutex_lock(&trace_types_lock);
4134 if (unlikely(iter->trace->name != tr->current_trace->name))
4135 *iter->trace = *tr->current_trace;
4136 mutex_unlock(&trace_types_lock);
4139 * Avoid more than one consumer on a single file descriptor
4140 * This is just a matter of traces coherency, the ring buffer itself
4143 mutex_lock(&iter->mutex);
4144 if (iter->trace->read) {
4145 sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
4151 sret = tracing_wait_pipe(filp);
4155 /* stop when tracing is finished */
4156 if (trace_empty(iter)) {
4161 if (cnt >= PAGE_SIZE)
4162 cnt = PAGE_SIZE - 1;
4164 /* reset all but tr, trace, and overruns */
4165 memset(&iter->seq, 0,
4166 sizeof(struct trace_iterator) -
4167 offsetof(struct trace_iterator, seq));
4168 cpumask_clear(iter->started);
4171 trace_event_read_lock();
4172 trace_access_lock(iter->cpu_file);
4173 while (trace_find_next_entry_inc(iter) != NULL) {
4174 enum print_line_t ret;
4175 int len = iter->seq.len;
4177 ret = print_trace_line(iter);
4178 if (ret == TRACE_TYPE_PARTIAL_LINE) {
4179 /* don't print partial lines */
4180 iter->seq.len = len;
4183 if (ret != TRACE_TYPE_NO_CONSUME)
4184 trace_consume(iter);
4186 if (iter->seq.len >= cnt)
4190 * Setting the full flag means we reached the trace_seq buffer
4191 * size and we should leave by partial output condition above.
4192 * One of the trace_seq_* functions is not used properly.
4194 WARN_ONCE(iter->seq.full, "full flag set for trace type %d",
4197 trace_access_unlock(iter->cpu_file);
4198 trace_event_read_unlock();
4200 /* Now copy what we have to the user */
4201 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
4202 if (iter->seq.readpos >= iter->seq.len)
4203 trace_seq_init(&iter->seq);
4206 * If there was nothing to send to user, in spite of consuming trace
4207 * entries, go back to wait for more entries.
4213 mutex_unlock(&iter->mutex);
4218 static void tracing_pipe_buf_release(struct pipe_inode_info *pipe,
4219 struct pipe_buffer *buf)
4221 __free_page(buf->page);
4224 static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
4227 __free_page(spd->pages[idx]);
4230 static const struct pipe_buf_operations tracing_pipe_buf_ops = {
4232 .map = generic_pipe_buf_map,
4233 .unmap = generic_pipe_buf_unmap,
4234 .confirm = generic_pipe_buf_confirm,
4235 .release = tracing_pipe_buf_release,
4236 .steal = generic_pipe_buf_steal,
4237 .get = generic_pipe_buf_get,
4241 tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
4246 /* Seq buffer is page-sized, exactly what we need. */
4248 count = iter->seq.len;
4249 ret = print_trace_line(iter);
4250 count = iter->seq.len - count;
4253 iter->seq.len -= count;
4256 if (ret == TRACE_TYPE_PARTIAL_LINE) {
4257 iter->seq.len -= count;
4261 if (ret != TRACE_TYPE_NO_CONSUME)
4262 trace_consume(iter);
4264 if (!trace_find_next_entry_inc(iter)) {
4274 static ssize_t tracing_splice_read_pipe(struct file *filp,
4276 struct pipe_inode_info *pipe,
4280 struct page *pages_def[PIPE_DEF_BUFFERS];
4281 struct partial_page partial_def[PIPE_DEF_BUFFERS];
4282 struct trace_iterator *iter = filp->private_data;
4283 struct splice_pipe_desc spd = {
4285 .partial = partial_def,
4286 .nr_pages = 0, /* This gets updated below. */
4287 .nr_pages_max = PIPE_DEF_BUFFERS,
4289 .ops = &tracing_pipe_buf_ops,
4290 .spd_release = tracing_spd_release_pipe,
4292 struct trace_array *tr = iter->tr;
4297 if (splice_grow_spd(pipe, &spd))
4300 /* copy the tracer to avoid using a global lock all around */
4301 mutex_lock(&trace_types_lock);
4302 if (unlikely(iter->trace->name != tr->current_trace->name))
4303 *iter->trace = *tr->current_trace;
4304 mutex_unlock(&trace_types_lock);
4306 mutex_lock(&iter->mutex);
4308 if (iter->trace->splice_read) {
4309 ret = iter->trace->splice_read(iter, filp,
4310 ppos, pipe, len, flags);
4315 ret = tracing_wait_pipe(filp);
4319 if (!iter->ent && !trace_find_next_entry_inc(iter)) {
4324 trace_event_read_lock();
4325 trace_access_lock(iter->cpu_file);
4327 /* Fill as many pages as possible. */
4328 for (i = 0, rem = len; i < pipe->buffers && rem; i++) {
4329 spd.pages[i] = alloc_page(GFP_KERNEL);
4333 rem = tracing_fill_pipe_page(rem, iter);
4335 /* Copy the data into the page, so we can start over. */
4336 ret = trace_seq_to_buffer(&iter->seq,
4337 page_address(spd.pages[i]),
4340 __free_page(spd.pages[i]);
4343 spd.partial[i].offset = 0;
4344 spd.partial[i].len = iter->seq.len;
4346 trace_seq_init(&iter->seq);
4349 trace_access_unlock(iter->cpu_file);
4350 trace_event_read_unlock();
4351 mutex_unlock(&iter->mutex);
4355 ret = splice_to_pipe(pipe, &spd);
4357 splice_shrink_spd(&spd);
4361 mutex_unlock(&iter->mutex);
4366 tracing_entries_read(struct file *filp, char __user *ubuf,
4367 size_t cnt, loff_t *ppos)
4369 struct trace_cpu *tc = filp->private_data;
4370 struct trace_array *tr = tc->tr;
4375 mutex_lock(&trace_types_lock);
4377 if (tc->cpu == RING_BUFFER_ALL_CPUS) {
4378 int cpu, buf_size_same;
4383 /* check if all cpu sizes are same */
4384 for_each_tracing_cpu(cpu) {
4385 /* fill in the size from first enabled cpu */
4387 size = per_cpu_ptr(tr->trace_buffer.data, cpu)->entries;
4388 if (size != per_cpu_ptr(tr->trace_buffer.data, cpu)->entries) {
4394 if (buf_size_same) {
4395 if (!ring_buffer_expanded)
4396 r = sprintf(buf, "%lu (expanded: %lu)\n",
4398 trace_buf_size >> 10);
4400 r = sprintf(buf, "%lu\n", size >> 10);
4402 r = sprintf(buf, "X\n");
4404 r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->trace_buffer.data, tc->cpu)->entries >> 10);
4406 mutex_unlock(&trace_types_lock);
4408 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
4413 tracing_entries_write(struct file *filp, const char __user *ubuf,
4414 size_t cnt, loff_t *ppos)
4416 struct trace_cpu *tc = filp->private_data;
4420 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
4424 /* must have at least 1 entry */
4428 /* value is in KB */
4431 ret = tracing_resize_ring_buffer(tc->tr, val, tc->cpu);
4441 tracing_total_entries_read(struct file *filp, char __user *ubuf,
4442 size_t cnt, loff_t *ppos)
4444 struct trace_array *tr = filp->private_data;
4447 unsigned long size = 0, expanded_size = 0;
4449 mutex_lock(&trace_types_lock);
4450 for_each_tracing_cpu(cpu) {
4451 size += per_cpu_ptr(tr->trace_buffer.data, cpu)->entries >> 10;
4452 if (!ring_buffer_expanded)
4453 expanded_size += trace_buf_size >> 10;
4455 if (ring_buffer_expanded)
4456 r = sprintf(buf, "%lu\n", size);
4458 r = sprintf(buf, "%lu (expanded: %lu)\n", size, expanded_size);
4459 mutex_unlock(&trace_types_lock);
4461 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
4465 tracing_free_buffer_write(struct file *filp, const char __user *ubuf,
4466 size_t cnt, loff_t *ppos)
4469 * There is no need to read what the user has written, this function
4470 * is just to make sure that there is no error when "echo" is used
4479 tracing_free_buffer_release(struct inode *inode, struct file *filp)
4481 struct trace_array *tr = inode->i_private;
4483 /* disable tracing ? */
4484 if (trace_flags & TRACE_ITER_STOP_ON_FREE)
4485 tracer_tracing_off(tr);
4486 /* resize the ring buffer to 0 */
4487 tracing_resize_ring_buffer(tr, 0, RING_BUFFER_ALL_CPUS);
4489 trace_array_put(tr);
4495 tracing_mark_write(struct file *filp, const char __user *ubuf,
4496 size_t cnt, loff_t *fpos)
4498 unsigned long addr = (unsigned long)ubuf;
4499 struct trace_array *tr = filp->private_data;
4500 struct ring_buffer_event *event;
4501 struct ring_buffer *buffer;
4502 struct print_entry *entry;
4503 unsigned long irq_flags;
4504 struct page *pages[2];
4514 if (tracing_disabled)
4517 if (!(trace_flags & TRACE_ITER_MARKERS))
4520 if (cnt > TRACE_BUF_SIZE)
4521 cnt = TRACE_BUF_SIZE;
4524 * Userspace is injecting traces into the kernel trace buffer.
4525 * We want to be as non intrusive as possible.
4526 * To do so, we do not want to allocate any special buffers
4527 * or take any locks, but instead write the userspace data
4528 * straight into the ring buffer.
4530 * First we need to pin the userspace buffer into memory,
4531 * which, most likely it is, because it just referenced it.
4532 * But there's no guarantee that it is. By using get_user_pages_fast()
4533 * and kmap_atomic/kunmap_atomic() we can get access to the
4534 * pages directly. We then write the data directly into the
4537 BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
4539 /* check if we cross pages */
4540 if ((addr & PAGE_MASK) != ((addr + cnt) & PAGE_MASK))
4543 offset = addr & (PAGE_SIZE - 1);
4546 ret = get_user_pages_fast(addr, nr_pages, 0, pages);
4547 if (ret < nr_pages) {
4549 put_page(pages[ret]);
4554 for (i = 0; i < nr_pages; i++)
4555 map_page[i] = kmap_atomic(pages[i]);
4557 local_save_flags(irq_flags);
4558 size = sizeof(*entry) + cnt + 2; /* possible \n added */
4559 buffer = tr->trace_buffer.buffer;
4560 event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
4561 irq_flags, preempt_count());
4563 /* Ring buffer disabled, return as if not open for write */
4568 entry = ring_buffer_event_data(event);
4569 entry->ip = _THIS_IP_;
4571 if (nr_pages == 2) {
4572 len = PAGE_SIZE - offset;
4573 memcpy(&entry->buf, map_page[0] + offset, len);
4574 memcpy(&entry->buf[len], map_page[1], cnt - len);
4576 memcpy(&entry->buf, map_page[0] + offset, cnt);
4578 if (entry->buf[cnt - 1] != '\n') {
4579 entry->buf[cnt] = '\n';
4580 entry->buf[cnt + 1] = '\0';
4582 entry->buf[cnt] = '\0';
4584 __buffer_unlock_commit(buffer, event);
4591 for (i = 0; i < nr_pages; i++){
4592 kunmap_atomic(map_page[i]);
4599 static int tracing_clock_show(struct seq_file *m, void *v)
4601 struct trace_array *tr = m->private;
4604 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++)
4606 "%s%s%s%s", i ? " " : "",
4607 i == tr->clock_id ? "[" : "", trace_clocks[i].name,
4608 i == tr->clock_id ? "]" : "");
4614 static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf,
4615 size_t cnt, loff_t *fpos)
4617 struct seq_file *m = filp->private_data;
4618 struct trace_array *tr = m->private;
4620 const char *clockstr;
4623 if (cnt >= sizeof(buf))
4626 if (copy_from_user(&buf, ubuf, cnt))
4631 clockstr = strstrip(buf);
4633 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) {
4634 if (strcmp(trace_clocks[i].name, clockstr) == 0)
4637 if (i == ARRAY_SIZE(trace_clocks))
4640 mutex_lock(&trace_types_lock);
4644 ring_buffer_set_clock(tr->trace_buffer.buffer, trace_clocks[i].func);
4647 * New clock may not be consistent with the previous clock.
4648 * Reset the buffer so that it doesn't have incomparable timestamps.
4650 tracing_reset_online_cpus(&tr->trace_buffer);
4652 #ifdef CONFIG_TRACER_MAX_TRACE
4653 if (tr->flags & TRACE_ARRAY_FL_GLOBAL && tr->max_buffer.buffer)
4654 ring_buffer_set_clock(tr->max_buffer.buffer, trace_clocks[i].func);
4655 tracing_reset_online_cpus(&tr->max_buffer);
4658 mutex_unlock(&trace_types_lock);
4665 static int tracing_clock_open(struct inode *inode, struct file *file)
4667 struct trace_array *tr = inode->i_private;
4670 if (tracing_disabled)
4673 if (trace_array_get(tr))
4676 ret = single_open(file, tracing_clock_show, inode->i_private);
4678 trace_array_put(tr);
4683 struct ftrace_buffer_info {
4684 struct trace_iterator iter;
4689 #ifdef CONFIG_TRACER_SNAPSHOT
4690 static int tracing_snapshot_open(struct inode *inode, struct file *file)
4692 struct trace_cpu *tc = inode->i_private;
4693 struct trace_array *tr = tc->tr;
4694 struct trace_iterator *iter;
4698 if (trace_array_get(tr) < 0)
4701 if (file->f_mode & FMODE_READ) {
4702 iter = __tracing_open(tr, tc, inode, file, true);
4704 ret = PTR_ERR(iter);
4706 /* Writes still need the seq_file to hold the private data */
4708 m = kzalloc(sizeof(*m), GFP_KERNEL);
4711 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
4719 iter->trace_buffer = &tc->tr->max_buffer;
4720 iter->cpu_file = tc->cpu;
4722 file->private_data = m;
4726 trace_array_put(tr);
4732 tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
4735 struct seq_file *m = filp->private_data;
4736 struct trace_iterator *iter = m->private;
4737 struct trace_array *tr = iter->tr;
4741 ret = tracing_update_buffers();
4745 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
4749 mutex_lock(&trace_types_lock);
4751 if (tr->current_trace->use_max_tr) {
4758 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
4762 if (tr->allocated_snapshot)
4766 /* Only allow per-cpu swap if the ring buffer supports it */
4767 #ifndef CONFIG_RING_BUFFER_ALLOW_SWAP
4768 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
4773 if (!tr->allocated_snapshot) {
4774 ret = alloc_snapshot(tr);
4778 local_irq_disable();
4779 /* Now, we're going to swap */
4780 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
4781 update_max_tr(tr, current, smp_processor_id());
4783 update_max_tr_single(tr, current, iter->cpu_file);
4787 if (tr->allocated_snapshot) {
4788 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
4789 tracing_reset_online_cpus(&tr->max_buffer);
4791 tracing_reset(&tr->max_buffer, iter->cpu_file);
4801 mutex_unlock(&trace_types_lock);
4805 static int tracing_snapshot_release(struct inode *inode, struct file *file)
4807 struct seq_file *m = file->private_data;
4810 ret = tracing_release(inode, file);
4812 if (file->f_mode & FMODE_READ)
4815 /* If write only, the seq_file is just a stub */
4823 static int tracing_buffers_open(struct inode *inode, struct file *filp);
4824 static ssize_t tracing_buffers_read(struct file *filp, char __user *ubuf,
4825 size_t count, loff_t *ppos);
4826 static int tracing_buffers_release(struct inode *inode, struct file *file);
4827 static ssize_t tracing_buffers_splice_read(struct file *file, loff_t *ppos,
4828 struct pipe_inode_info *pipe, size_t len, unsigned int flags);
4830 static int snapshot_raw_open(struct inode *inode, struct file *filp)
4832 struct ftrace_buffer_info *info;
4835 ret = tracing_buffers_open(inode, filp);
4839 info = filp->private_data;
4841 if (info->iter.trace->use_max_tr) {
4842 tracing_buffers_release(inode, filp);
4846 info->iter.snapshot = true;
4847 info->iter.trace_buffer = &info->iter.tr->max_buffer;
4852 #endif /* CONFIG_TRACER_SNAPSHOT */
4855 static const struct file_operations tracing_max_lat_fops = {
4856 .open = tracing_open_generic,
4857 .read = tracing_max_lat_read,
4858 .write = tracing_max_lat_write,
4859 .llseek = generic_file_llseek,
4862 static const struct file_operations set_tracer_fops = {
4863 .open = tracing_open_generic,
4864 .read = tracing_set_trace_read,
4865 .write = tracing_set_trace_write,
4866 .llseek = generic_file_llseek,
4869 static const struct file_operations tracing_pipe_fops = {
4870 .open = tracing_open_pipe,
4871 .poll = tracing_poll_pipe,
4872 .read = tracing_read_pipe,
4873 .splice_read = tracing_splice_read_pipe,
4874 .release = tracing_release_pipe,
4875 .llseek = no_llseek,
4878 static const struct file_operations tracing_entries_fops = {
4879 .open = tracing_open_generic_tc,
4880 .read = tracing_entries_read,
4881 .write = tracing_entries_write,
4882 .llseek = generic_file_llseek,
4883 .release = tracing_release_generic_tc,
4886 static const struct file_operations tracing_total_entries_fops = {
4887 .open = tracing_open_generic_tr,
4888 .read = tracing_total_entries_read,
4889 .llseek = generic_file_llseek,
4890 .release = tracing_release_generic_tr,
4893 static const struct file_operations tracing_free_buffer_fops = {
4894 .open = tracing_open_generic_tr,
4895 .write = tracing_free_buffer_write,
4896 .release = tracing_free_buffer_release,
4899 static const struct file_operations tracing_mark_fops = {
4900 .open = tracing_open_generic_tr,
4901 .write = tracing_mark_write,
4902 .llseek = generic_file_llseek,
4903 .release = tracing_release_generic_tr,
4906 static const struct file_operations trace_clock_fops = {
4907 .open = tracing_clock_open,
4909 .llseek = seq_lseek,
4910 .release = tracing_single_release_tr,
4911 .write = tracing_clock_write,
4914 #ifdef CONFIG_TRACER_SNAPSHOT
4915 static const struct file_operations snapshot_fops = {
4916 .open = tracing_snapshot_open,
4918 .write = tracing_snapshot_write,
4919 .llseek = tracing_seek,
4920 .release = tracing_snapshot_release,
4923 static const struct file_operations snapshot_raw_fops = {
4924 .open = snapshot_raw_open,
4925 .read = tracing_buffers_read,
4926 .release = tracing_buffers_release,
4927 .splice_read = tracing_buffers_splice_read,
4928 .llseek = no_llseek,
4931 #endif /* CONFIG_TRACER_SNAPSHOT */
4933 static int tracing_buffers_open(struct inode *inode, struct file *filp)
4935 struct trace_cpu *tc = inode->i_private;
4936 struct trace_array *tr = tc->tr;
4937 struct ftrace_buffer_info *info;
4940 if (tracing_disabled)
4943 if (trace_array_get(tr) < 0)
4946 info = kzalloc(sizeof(*info), GFP_KERNEL);
4948 trace_array_put(tr);
4952 mutex_lock(&trace_types_lock);
4955 info->iter.cpu_file = tc->cpu;
4956 info->iter.trace = tr->current_trace;
4957 info->iter.trace_buffer = &tr->trace_buffer;
4959 /* Force reading ring buffer for first read */
4960 info->read = (unsigned int)-1;
4962 filp->private_data = info;
4964 mutex_unlock(&trace_types_lock);
4966 ret = nonseekable_open(inode, filp);
4968 trace_array_put(tr);
4974 tracing_buffers_poll(struct file *filp, poll_table *poll_table)
4976 struct ftrace_buffer_info *info = filp->private_data;
4977 struct trace_iterator *iter = &info->iter;
4979 return trace_poll(iter, filp, poll_table);
4983 tracing_buffers_read(struct file *filp, char __user *ubuf,
4984 size_t count, loff_t *ppos)
4986 struct ftrace_buffer_info *info = filp->private_data;
4987 struct trace_iterator *iter = &info->iter;
4994 mutex_lock(&trace_types_lock);
4996 #ifdef CONFIG_TRACER_MAX_TRACE
4997 if (iter->snapshot && iter->tr->current_trace->use_max_tr) {
5004 info->spare = ring_buffer_alloc_read_page(iter->trace_buffer->buffer,
5010 /* Do we have previous read data to read? */
5011 if (info->read < PAGE_SIZE)
5015 trace_access_lock(iter->cpu_file);
5016 ret = ring_buffer_read_page(iter->trace_buffer->buffer,
5020 trace_access_unlock(iter->cpu_file);
5023 if (trace_empty(iter)) {
5024 if ((filp->f_flags & O_NONBLOCK)) {
5028 mutex_unlock(&trace_types_lock);
5029 iter->trace->wait_pipe(iter);
5030 mutex_lock(&trace_types_lock);
5031 if (signal_pending(current)) {
5043 size = PAGE_SIZE - info->read;
5047 ret = copy_to_user(ubuf, info->spare + info->read, size);
5058 mutex_unlock(&trace_types_lock);
5063 static int tracing_buffers_release(struct inode *inode, struct file *file)
5065 struct ftrace_buffer_info *info = file->private_data;
5066 struct trace_iterator *iter = &info->iter;
5068 mutex_lock(&trace_types_lock);
5070 __trace_array_put(iter->tr);
5073 ring_buffer_free_read_page(iter->trace_buffer->buffer, info->spare);
5076 mutex_unlock(&trace_types_lock);
5082 struct ring_buffer *buffer;
5087 static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
5088 struct pipe_buffer *buf)
5090 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
5095 ring_buffer_free_read_page(ref->buffer, ref->page);
5100 static void buffer_pipe_buf_get(struct pipe_inode_info *pipe,
5101 struct pipe_buffer *buf)
5103 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
5108 /* Pipe buffer operations for a buffer. */
5109 static const struct pipe_buf_operations buffer_pipe_buf_ops = {
5111 .map = generic_pipe_buf_map,
5112 .unmap = generic_pipe_buf_unmap,
5113 .confirm = generic_pipe_buf_confirm,
5114 .release = buffer_pipe_buf_release,
5115 .steal = generic_pipe_buf_steal,
5116 .get = buffer_pipe_buf_get,
5120 * Callback from splice_to_pipe(), if we need to release some pages
5121 * at the end of the spd in case we error'ed out in filling the pipe.
5123 static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
5125 struct buffer_ref *ref =
5126 (struct buffer_ref *)spd->partial[i].private;
5131 ring_buffer_free_read_page(ref->buffer, ref->page);
5133 spd->partial[i].private = 0;
5137 tracing_buffers_splice_read(struct file *file, loff_t *ppos,
5138 struct pipe_inode_info *pipe, size_t len,
5141 struct ftrace_buffer_info *info = file->private_data;
5142 struct trace_iterator *iter = &info->iter;
5143 struct partial_page partial_def[PIPE_DEF_BUFFERS];
5144 struct page *pages_def[PIPE_DEF_BUFFERS];
5145 struct splice_pipe_desc spd = {
5147 .partial = partial_def,
5148 .nr_pages_max = PIPE_DEF_BUFFERS,
5150 .ops = &buffer_pipe_buf_ops,
5151 .spd_release = buffer_spd_release,
5153 struct buffer_ref *ref;
5154 int entries, size, i;
5157 mutex_lock(&trace_types_lock);
5159 #ifdef CONFIG_TRACER_MAX_TRACE
5160 if (iter->snapshot && iter->tr->current_trace->use_max_tr) {
5166 if (splice_grow_spd(pipe, &spd)) {
5171 if (*ppos & (PAGE_SIZE - 1)) {
5176 if (len & (PAGE_SIZE - 1)) {
5177 if (len < PAGE_SIZE) {
5185 trace_access_lock(iter->cpu_file);
5186 entries = ring_buffer_entries_cpu(iter->trace_buffer->buffer, iter->cpu_file);
5188 for (i = 0; i < pipe->buffers && len && entries; i++, len -= PAGE_SIZE) {
5192 ref = kzalloc(sizeof(*ref), GFP_KERNEL);
5197 ref->buffer = iter->trace_buffer->buffer;
5198 ref->page = ring_buffer_alloc_read_page(ref->buffer, iter->cpu_file);
5204 r = ring_buffer_read_page(ref->buffer, &ref->page,
5205 len, iter->cpu_file, 1);
5207 ring_buffer_free_read_page(ref->buffer, ref->page);
5213 * zero out any left over data, this is going to
5216 size = ring_buffer_page_len(ref->page);
5217 if (size < PAGE_SIZE)
5218 memset(ref->page + size, 0, PAGE_SIZE - size);
5220 page = virt_to_page(ref->page);
5222 spd.pages[i] = page;
5223 spd.partial[i].len = PAGE_SIZE;
5224 spd.partial[i].offset = 0;
5225 spd.partial[i].private = (unsigned long)ref;
5229 entries = ring_buffer_entries_cpu(iter->trace_buffer->buffer, iter->cpu_file);
5232 trace_access_unlock(iter->cpu_file);
5235 /* did we read anything? */
5236 if (!spd.nr_pages) {
5237 if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK)) {
5241 mutex_unlock(&trace_types_lock);
5242 iter->trace->wait_pipe(iter);
5243 mutex_lock(&trace_types_lock);
5244 if (signal_pending(current)) {
5251 ret = splice_to_pipe(pipe, &spd);
5252 splice_shrink_spd(&spd);
5254 mutex_unlock(&trace_types_lock);
5259 static const struct file_operations tracing_buffers_fops = {
5260 .open = tracing_buffers_open,
5261 .read = tracing_buffers_read,
5262 .poll = tracing_buffers_poll,
5263 .release = tracing_buffers_release,
5264 .splice_read = tracing_buffers_splice_read,
5265 .llseek = no_llseek,
5269 tracing_stats_read(struct file *filp, char __user *ubuf,
5270 size_t count, loff_t *ppos)
5272 struct trace_cpu *tc = filp->private_data;
5273 struct trace_array *tr = tc->tr;
5274 struct trace_buffer *trace_buf = &tr->trace_buffer;
5275 struct trace_seq *s;
5277 unsigned long long t;
5278 unsigned long usec_rem;
5281 s = kmalloc(sizeof(*s), GFP_KERNEL);
5287 cnt = ring_buffer_entries_cpu(trace_buf->buffer, cpu);
5288 trace_seq_printf(s, "entries: %ld\n", cnt);
5290 cnt = ring_buffer_overrun_cpu(trace_buf->buffer, cpu);
5291 trace_seq_printf(s, "overrun: %ld\n", cnt);
5293 cnt = ring_buffer_commit_overrun_cpu(trace_buf->buffer, cpu);
5294 trace_seq_printf(s, "commit overrun: %ld\n", cnt);
5296 cnt = ring_buffer_bytes_cpu(trace_buf->buffer, cpu);
5297 trace_seq_printf(s, "bytes: %ld\n", cnt);
5299 if (trace_clocks[tr->clock_id].in_ns) {
5300 /* local or global for trace_clock */
5301 t = ns2usecs(ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
5302 usec_rem = do_div(t, USEC_PER_SEC);
5303 trace_seq_printf(s, "oldest event ts: %5llu.%06lu\n",
5306 t = ns2usecs(ring_buffer_time_stamp(trace_buf->buffer, cpu));
5307 usec_rem = do_div(t, USEC_PER_SEC);
5308 trace_seq_printf(s, "now ts: %5llu.%06lu\n", t, usec_rem);
5310 /* counter or tsc mode for trace_clock */
5311 trace_seq_printf(s, "oldest event ts: %llu\n",
5312 ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
5314 trace_seq_printf(s, "now ts: %llu\n",
5315 ring_buffer_time_stamp(trace_buf->buffer, cpu));
5318 cnt = ring_buffer_dropped_events_cpu(trace_buf->buffer, cpu);
5319 trace_seq_printf(s, "dropped events: %ld\n", cnt);
5321 cnt = ring_buffer_read_events_cpu(trace_buf->buffer, cpu);
5322 trace_seq_printf(s, "read events: %ld\n", cnt);
5324 count = simple_read_from_buffer(ubuf, count, ppos, s->buffer, s->len);
5331 static const struct file_operations tracing_stats_fops = {
5332 .open = tracing_open_generic_tc,
5333 .read = tracing_stats_read,
5334 .llseek = generic_file_llseek,
5335 .release = tracing_release_generic_tc,
5338 #ifdef CONFIG_DYNAMIC_FTRACE
5340 int __weak ftrace_arch_read_dyn_info(char *buf, int size)
5346 tracing_read_dyn_info(struct file *filp, char __user *ubuf,
5347 size_t cnt, loff_t *ppos)
5349 static char ftrace_dyn_info_buffer[1024];
5350 static DEFINE_MUTEX(dyn_info_mutex);
5351 unsigned long *p = filp->private_data;
5352 char *buf = ftrace_dyn_info_buffer;
5353 int size = ARRAY_SIZE(ftrace_dyn_info_buffer);
5356 mutex_lock(&dyn_info_mutex);
5357 r = sprintf(buf, "%ld ", *p);
5359 r += ftrace_arch_read_dyn_info(buf+r, (size-1)-r);
5362 r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
5364 mutex_unlock(&dyn_info_mutex);
5369 static const struct file_operations tracing_dyn_info_fops = {
5370 .open = tracing_open_generic,
5371 .read = tracing_read_dyn_info,
5372 .llseek = generic_file_llseek,
5374 #endif /* CONFIG_DYNAMIC_FTRACE */
5376 #if defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE)
5378 ftrace_snapshot(unsigned long ip, unsigned long parent_ip, void **data)
5384 ftrace_count_snapshot(unsigned long ip, unsigned long parent_ip, void **data)
5386 unsigned long *count = (long *)data;
5398 ftrace_snapshot_print(struct seq_file *m, unsigned long ip,
5399 struct ftrace_probe_ops *ops, void *data)
5401 long count = (long)data;
5403 seq_printf(m, "%ps:", (void *)ip);
5405 seq_printf(m, "snapshot");
5408 seq_printf(m, ":unlimited\n");
5410 seq_printf(m, ":count=%ld\n", count);
5415 static struct ftrace_probe_ops snapshot_probe_ops = {
5416 .func = ftrace_snapshot,
5417 .print = ftrace_snapshot_print,
5420 static struct ftrace_probe_ops snapshot_count_probe_ops = {
5421 .func = ftrace_count_snapshot,
5422 .print = ftrace_snapshot_print,
5426 ftrace_trace_snapshot_callback(struct ftrace_hash *hash,
5427 char *glob, char *cmd, char *param, int enable)
5429 struct ftrace_probe_ops *ops;
5430 void *count = (void *)-1;
5434 /* hash funcs only work with set_ftrace_filter */
5438 ops = param ? &snapshot_count_probe_ops : &snapshot_probe_ops;
5440 if (glob[0] == '!') {
5441 unregister_ftrace_function_probe_func(glob+1, ops);
5448 number = strsep(¶m, ":");
5450 if (!strlen(number))
5454 * We use the callback data field (which is a pointer)
5457 ret = kstrtoul(number, 0, (unsigned long *)&count);
5462 ret = register_ftrace_function_probe(glob, ops, count);
5465 alloc_snapshot(&global_trace);
5467 return ret < 0 ? ret : 0;
5470 static struct ftrace_func_command ftrace_snapshot_cmd = {
5472 .func = ftrace_trace_snapshot_callback,
5475 static int register_snapshot_cmd(void)
5477 return register_ftrace_command(&ftrace_snapshot_cmd);
5480 static inline int register_snapshot_cmd(void) { return 0; }
5481 #endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
5483 struct dentry *tracing_init_dentry_tr(struct trace_array *tr)
5488 if (!debugfs_initialized())
5491 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
5492 tr->dir = debugfs_create_dir("tracing", NULL);
5495 pr_warn_once("Could not create debugfs directory 'tracing'\n");
5500 struct dentry *tracing_init_dentry(void)
5502 return tracing_init_dentry_tr(&global_trace);
5505 static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu)
5507 struct dentry *d_tracer;
5510 return tr->percpu_dir;
5512 d_tracer = tracing_init_dentry_tr(tr);
5516 tr->percpu_dir = debugfs_create_dir("per_cpu", d_tracer);
5518 WARN_ONCE(!tr->percpu_dir,
5519 "Could not create debugfs directory 'per_cpu/%d'\n", cpu);
5521 return tr->percpu_dir;
5525 tracing_init_debugfs_percpu(struct trace_array *tr, long cpu)
5527 struct trace_array_cpu *data = per_cpu_ptr(tr->trace_buffer.data, cpu);
5528 struct dentry *d_percpu = tracing_dentry_percpu(tr, cpu);
5529 struct dentry *d_cpu;
5530 char cpu_dir[30]; /* 30 characters should be more than enough */
5535 snprintf(cpu_dir, 30, "cpu%ld", cpu);
5536 d_cpu = debugfs_create_dir(cpu_dir, d_percpu);
5538 pr_warning("Could not create debugfs '%s' entry\n", cpu_dir);
5542 /* per cpu trace_pipe */
5543 trace_create_file("trace_pipe", 0444, d_cpu,
5544 (void *)&data->trace_cpu, &tracing_pipe_fops);
5547 trace_create_file("trace", 0644, d_cpu,
5548 (void *)&data->trace_cpu, &tracing_fops);
5550 trace_create_file("trace_pipe_raw", 0444, d_cpu,
5551 (void *)&data->trace_cpu, &tracing_buffers_fops);
5553 trace_create_file("stats", 0444, d_cpu,
5554 (void *)&data->trace_cpu, &tracing_stats_fops);
5556 trace_create_file("buffer_size_kb", 0444, d_cpu,
5557 (void *)&data->trace_cpu, &tracing_entries_fops);
5559 #ifdef CONFIG_TRACER_SNAPSHOT
5560 trace_create_file("snapshot", 0644, d_cpu,
5561 (void *)&data->trace_cpu, &snapshot_fops);
5563 trace_create_file("snapshot_raw", 0444, d_cpu,
5564 (void *)&data->trace_cpu, &snapshot_raw_fops);
5568 #ifdef CONFIG_FTRACE_SELFTEST
5569 /* Let selftest have access to static functions in this file */
5570 #include "trace_selftest.c"
5573 struct trace_option_dentry {
5574 struct tracer_opt *opt;
5575 struct tracer_flags *flags;
5576 struct trace_array *tr;
5577 struct dentry *entry;
5581 trace_options_read(struct file *filp, char __user *ubuf, size_t cnt,
5584 struct trace_option_dentry *topt = filp->private_data;
5587 if (topt->flags->val & topt->opt->bit)
5592 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
5596 trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt,
5599 struct trace_option_dentry *topt = filp->private_data;
5603 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
5607 if (val != 0 && val != 1)
5610 if (!!(topt->flags->val & topt->opt->bit) != val) {
5611 mutex_lock(&trace_types_lock);
5612 ret = __set_tracer_option(topt->tr->current_trace, topt->flags,
5614 mutex_unlock(&trace_types_lock);
5625 static const struct file_operations trace_options_fops = {
5626 .open = tracing_open_generic,
5627 .read = trace_options_read,
5628 .write = trace_options_write,
5629 .llseek = generic_file_llseek,
5633 trace_options_core_read(struct file *filp, char __user *ubuf, size_t cnt,
5636 long index = (long)filp->private_data;
5639 if (trace_flags & (1 << index))
5644 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
5648 trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
5651 struct trace_array *tr = &global_trace;
5652 long index = (long)filp->private_data;
5656 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
5660 if (val != 0 && val != 1)
5663 mutex_lock(&trace_types_lock);
5664 ret = set_tracer_flag(tr, 1 << index, val);
5665 mutex_unlock(&trace_types_lock);
5675 static const struct file_operations trace_options_core_fops = {
5676 .open = tracing_open_generic,
5677 .read = trace_options_core_read,
5678 .write = trace_options_core_write,
5679 .llseek = generic_file_llseek,
5682 struct dentry *trace_create_file(const char *name,
5684 struct dentry *parent,
5686 const struct file_operations *fops)
5690 ret = debugfs_create_file(name, mode, parent, data, fops);
5692 pr_warning("Could not create debugfs '%s' entry\n", name);
5698 static struct dentry *trace_options_init_dentry(struct trace_array *tr)
5700 struct dentry *d_tracer;
5705 d_tracer = tracing_init_dentry_tr(tr);
5709 tr->options = debugfs_create_dir("options", d_tracer);
5711 pr_warning("Could not create debugfs directory 'options'\n");
5719 create_trace_option_file(struct trace_array *tr,
5720 struct trace_option_dentry *topt,
5721 struct tracer_flags *flags,
5722 struct tracer_opt *opt)
5724 struct dentry *t_options;
5726 t_options = trace_options_init_dentry(tr);
5730 topt->flags = flags;
5734 topt->entry = trace_create_file(opt->name, 0644, t_options, topt,
5735 &trace_options_fops);
5739 static struct trace_option_dentry *
5740 create_trace_option_files(struct trace_array *tr, struct tracer *tracer)
5742 struct trace_option_dentry *topts;
5743 struct tracer_flags *flags;
5744 struct tracer_opt *opts;
5750 flags = tracer->flags;
5752 if (!flags || !flags->opts)
5757 for (cnt = 0; opts[cnt].name; cnt++)
5760 topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL);
5764 for (cnt = 0; opts[cnt].name; cnt++)
5765 create_trace_option_file(tr, &topts[cnt], flags,
5772 destroy_trace_option_files(struct trace_option_dentry *topts)
5779 for (cnt = 0; topts[cnt].opt; cnt++) {
5780 if (topts[cnt].entry)
5781 debugfs_remove(topts[cnt].entry);
5787 static struct dentry *
5788 create_trace_option_core_file(struct trace_array *tr,
5789 const char *option, long index)
5791 struct dentry *t_options;
5793 t_options = trace_options_init_dentry(tr);
5797 return trace_create_file(option, 0644, t_options, (void *)index,
5798 &trace_options_core_fops);
5801 static __init void create_trace_options_dir(struct trace_array *tr)
5803 struct dentry *t_options;
5806 t_options = trace_options_init_dentry(tr);
5810 for (i = 0; trace_options[i]; i++)
5811 create_trace_option_core_file(tr, trace_options[i], i);
5815 rb_simple_read(struct file *filp, char __user *ubuf,
5816 size_t cnt, loff_t *ppos)
5818 struct trace_array *tr = filp->private_data;
5822 r = tracer_tracing_is_on(tr);
5823 r = sprintf(buf, "%d\n", r);
5825 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
5829 rb_simple_write(struct file *filp, const char __user *ubuf,
5830 size_t cnt, loff_t *ppos)
5832 struct trace_array *tr = filp->private_data;
5833 struct ring_buffer *buffer = tr->trace_buffer.buffer;
5837 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
5842 mutex_lock(&trace_types_lock);
5844 tracer_tracing_on(tr);
5845 if (tr->current_trace->start)
5846 tr->current_trace->start(tr);
5848 tracer_tracing_off(tr);
5849 if (tr->current_trace->stop)
5850 tr->current_trace->stop(tr);
5852 mutex_unlock(&trace_types_lock);
5860 static const struct file_operations rb_simple_fops = {
5861 .open = tracing_open_generic_tr,
5862 .read = rb_simple_read,
5863 .write = rb_simple_write,
5864 .release = tracing_release_generic_tr,
5865 .llseek = default_llseek,
5868 struct dentry *trace_instance_dir;
5871 init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer);
5873 static void init_trace_buffers(struct trace_array *tr, struct trace_buffer *buf)
5877 for_each_tracing_cpu(cpu) {
5878 memset(per_cpu_ptr(buf->data, cpu), 0, sizeof(struct trace_array_cpu));
5879 per_cpu_ptr(buf->data, cpu)->trace_cpu.cpu = cpu;
5880 per_cpu_ptr(buf->data, cpu)->trace_cpu.tr = tr;
5885 allocate_trace_buffer(struct trace_array *tr, struct trace_buffer *buf, int size)
5887 enum ring_buffer_flags rb_flags;
5889 rb_flags = trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0;
5891 buf->buffer = ring_buffer_alloc(size, rb_flags);
5895 buf->data = alloc_percpu(struct trace_array_cpu);
5897 ring_buffer_free(buf->buffer);
5901 init_trace_buffers(tr, buf);
5903 /* Allocate the first page for all buffers */
5904 set_buffer_entries(&tr->trace_buffer,
5905 ring_buffer_size(tr->trace_buffer.buffer, 0));
5910 static int allocate_trace_buffers(struct trace_array *tr, int size)
5914 ret = allocate_trace_buffer(tr, &tr->trace_buffer, size);
5918 #ifdef CONFIG_TRACER_MAX_TRACE
5919 ret = allocate_trace_buffer(tr, &tr->max_buffer,
5920 allocate_snapshot ? size : 1);
5922 ring_buffer_free(tr->trace_buffer.buffer);
5923 free_percpu(tr->trace_buffer.data);
5926 tr->allocated_snapshot = allocate_snapshot;
5929 * Only the top level trace array gets its snapshot allocated
5930 * from the kernel command line.
5932 allocate_snapshot = false;
5937 static int new_instance_create(const char *name)
5939 struct trace_array *tr;
5942 mutex_lock(&trace_types_lock);
5945 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
5946 if (tr->name && strcmp(tr->name, name) == 0)
5951 tr = kzalloc(sizeof(*tr), GFP_KERNEL);
5955 tr->name = kstrdup(name, GFP_KERNEL);
5959 raw_spin_lock_init(&tr->start_lock);
5961 tr->current_trace = &nop_trace;
5963 INIT_LIST_HEAD(&tr->systems);
5964 INIT_LIST_HEAD(&tr->events);
5966 if (allocate_trace_buffers(tr, trace_buf_size) < 0)
5969 /* Holder for file callbacks */
5970 tr->trace_cpu.cpu = RING_BUFFER_ALL_CPUS;
5971 tr->trace_cpu.tr = tr;
5973 tr->dir = debugfs_create_dir(name, trace_instance_dir);
5977 ret = event_trace_add_tracer(tr->dir, tr);
5979 debugfs_remove_recursive(tr->dir);
5983 init_tracer_debugfs(tr, tr->dir);
5985 list_add(&tr->list, &ftrace_trace_arrays);
5987 mutex_unlock(&trace_types_lock);
5992 if (tr->trace_buffer.buffer)
5993 ring_buffer_free(tr->trace_buffer.buffer);
5998 mutex_unlock(&trace_types_lock);
6004 static int instance_delete(const char *name)
6006 struct trace_array *tr;
6010 mutex_lock(&trace_types_lock);
6013 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6014 if (tr->name && strcmp(tr->name, name) == 0) {
6026 list_del(&tr->list);
6028 event_trace_del_tracer(tr);
6029 debugfs_remove_recursive(tr->dir);
6030 free_percpu(tr->trace_buffer.data);
6031 ring_buffer_free(tr->trace_buffer.buffer);
6039 mutex_unlock(&trace_types_lock);
6044 static int instance_mkdir (struct inode *inode, struct dentry *dentry, umode_t mode)
6046 struct dentry *parent;
6049 /* Paranoid: Make sure the parent is the "instances" directory */
6050 parent = hlist_entry(inode->i_dentry.first, struct dentry, d_alias);
6051 if (WARN_ON_ONCE(parent != trace_instance_dir))
6055 * The inode mutex is locked, but debugfs_create_dir() will also
6056 * take the mutex. As the instances directory can not be destroyed
6057 * or changed in any other way, it is safe to unlock it, and
6058 * let the dentry try. If two users try to make the same dir at
6059 * the same time, then the new_instance_create() will determine the
6062 mutex_unlock(&inode->i_mutex);
6064 ret = new_instance_create(dentry->d_iname);
6066 mutex_lock(&inode->i_mutex);
6071 static int instance_rmdir(struct inode *inode, struct dentry *dentry)
6073 struct dentry *parent;
6076 /* Paranoid: Make sure the parent is the "instances" directory */
6077 parent = hlist_entry(inode->i_dentry.first, struct dentry, d_alias);
6078 if (WARN_ON_ONCE(parent != trace_instance_dir))
6081 /* The caller did a dget() on dentry */
6082 mutex_unlock(&dentry->d_inode->i_mutex);
6085 * The inode mutex is locked, but debugfs_create_dir() will also
6086 * take the mutex. As the instances directory can not be destroyed
6087 * or changed in any other way, it is safe to unlock it, and
6088 * let the dentry try. If two users try to make the same dir at
6089 * the same time, then the instance_delete() will determine the
6092 mutex_unlock(&inode->i_mutex);
6094 ret = instance_delete(dentry->d_iname);
6096 mutex_lock_nested(&inode->i_mutex, I_MUTEX_PARENT);
6097 mutex_lock(&dentry->d_inode->i_mutex);
6102 static const struct inode_operations instance_dir_inode_operations = {
6103 .lookup = simple_lookup,
6104 .mkdir = instance_mkdir,
6105 .rmdir = instance_rmdir,
6108 static __init void create_trace_instances(struct dentry *d_tracer)
6110 trace_instance_dir = debugfs_create_dir("instances", d_tracer);
6111 if (WARN_ON(!trace_instance_dir))
6114 /* Hijack the dir inode operations, to allow mkdir */
6115 trace_instance_dir->d_inode->i_op = &instance_dir_inode_operations;
6119 init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer)
6123 trace_create_file("trace_options", 0644, d_tracer,
6124 tr, &tracing_iter_fops);
6126 trace_create_file("trace", 0644, d_tracer,
6127 (void *)&tr->trace_cpu, &tracing_fops);
6129 trace_create_file("trace_pipe", 0444, d_tracer,
6130 (void *)&tr->trace_cpu, &tracing_pipe_fops);
6132 trace_create_file("buffer_size_kb", 0644, d_tracer,
6133 (void *)&tr->trace_cpu, &tracing_entries_fops);
6135 trace_create_file("buffer_total_size_kb", 0444, d_tracer,
6136 tr, &tracing_total_entries_fops);
6138 trace_create_file("free_buffer", 0644, d_tracer,
6139 tr, &tracing_free_buffer_fops);
6141 trace_create_file("trace_marker", 0220, d_tracer,
6142 tr, &tracing_mark_fops);
6144 trace_create_file("trace_clock", 0644, d_tracer, tr,
6147 trace_create_file("tracing_on", 0644, d_tracer,
6148 tr, &rb_simple_fops);
6150 #ifdef CONFIG_TRACER_SNAPSHOT
6151 trace_create_file("snapshot", 0644, d_tracer,
6152 (void *)&tr->trace_cpu, &snapshot_fops);
6155 for_each_tracing_cpu(cpu)
6156 tracing_init_debugfs_percpu(tr, cpu);
6160 static __init int tracer_init_debugfs(void)
6162 struct dentry *d_tracer;
6164 trace_access_lock_init();
6166 d_tracer = tracing_init_dentry();
6170 init_tracer_debugfs(&global_trace, d_tracer);
6172 trace_create_file("tracing_cpumask", 0644, d_tracer,
6173 &global_trace, &tracing_cpumask_fops);
6175 trace_create_file("available_tracers", 0444, d_tracer,
6176 &global_trace, &show_traces_fops);
6178 trace_create_file("current_tracer", 0644, d_tracer,
6179 &global_trace, &set_tracer_fops);
6181 #ifdef CONFIG_TRACER_MAX_TRACE
6182 trace_create_file("tracing_max_latency", 0644, d_tracer,
6183 &tracing_max_latency, &tracing_max_lat_fops);
6186 trace_create_file("tracing_thresh", 0644, d_tracer,
6187 &tracing_thresh, &tracing_max_lat_fops);
6189 trace_create_file("README", 0444, d_tracer,
6190 NULL, &tracing_readme_fops);
6192 trace_create_file("saved_cmdlines", 0444, d_tracer,
6193 NULL, &tracing_saved_cmdlines_fops);
6195 #ifdef CONFIG_DYNAMIC_FTRACE
6196 trace_create_file("dyn_ftrace_total_info", 0444, d_tracer,
6197 &ftrace_update_tot_cnt, &tracing_dyn_info_fops);
6200 create_trace_instances(d_tracer);
6202 create_trace_options_dir(&global_trace);
6207 static int trace_panic_handler(struct notifier_block *this,
6208 unsigned long event, void *unused)
6210 if (ftrace_dump_on_oops)
6211 ftrace_dump(ftrace_dump_on_oops);
6215 static struct notifier_block trace_panic_notifier = {
6216 .notifier_call = trace_panic_handler,
6218 .priority = 150 /* priority: INT_MAX >= x >= 0 */
6221 static int trace_die_handler(struct notifier_block *self,
6227 if (ftrace_dump_on_oops)
6228 ftrace_dump(ftrace_dump_on_oops);
6236 static struct notifier_block trace_die_notifier = {
6237 .notifier_call = trace_die_handler,
6242 * printk is set to max of 1024, we really don't need it that big.
6243 * Nothing should be printing 1000 characters anyway.
6245 #define TRACE_MAX_PRINT 1000
6248 * Define here KERN_TRACE so that we have one place to modify
6249 * it if we decide to change what log level the ftrace dump
6252 #define KERN_TRACE KERN_EMERG
6255 trace_printk_seq(struct trace_seq *s)
6257 /* Probably should print a warning here. */
6258 if (s->len >= TRACE_MAX_PRINT)
6259 s->len = TRACE_MAX_PRINT;
6261 /* should be zero ended, but we are paranoid. */
6262 s->buffer[s->len] = 0;
6264 printk(KERN_TRACE "%s", s->buffer);
6269 void trace_init_global_iter(struct trace_iterator *iter)
6271 iter->tr = &global_trace;
6272 iter->trace = iter->tr->current_trace;
6273 iter->cpu_file = RING_BUFFER_ALL_CPUS;
6274 iter->trace_buffer = &global_trace.trace_buffer;
6277 void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
6279 /* use static because iter can be a bit big for the stack */
6280 static struct trace_iterator iter;
6281 static atomic_t dump_running;
6282 unsigned int old_userobj;
6283 unsigned long flags;
6286 /* Only allow one dump user at a time. */
6287 if (atomic_inc_return(&dump_running) != 1) {
6288 atomic_dec(&dump_running);
6293 * Always turn off tracing when we dump.
6294 * We don't need to show trace output of what happens
6295 * between multiple crashes.
6297 * If the user does a sysrq-z, then they can re-enable
6298 * tracing with echo 1 > tracing_on.
6302 local_irq_save(flags);
6304 /* Simulate the iterator */
6305 trace_init_global_iter(&iter);
6307 for_each_tracing_cpu(cpu) {
6308 atomic_inc(&per_cpu_ptr(iter.tr->trace_buffer.data, cpu)->disabled);
6311 old_userobj = trace_flags & TRACE_ITER_SYM_USEROBJ;
6313 /* don't look at user memory in panic mode */
6314 trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
6316 switch (oops_dump_mode) {
6318 iter.cpu_file = RING_BUFFER_ALL_CPUS;
6321 iter.cpu_file = raw_smp_processor_id();
6326 printk(KERN_TRACE "Bad dumping mode, switching to all CPUs dump\n");
6327 iter.cpu_file = RING_BUFFER_ALL_CPUS;
6330 printk(KERN_TRACE "Dumping ftrace buffer:\n");
6332 /* Did function tracer already get disabled? */
6333 if (ftrace_is_dead()) {
6334 printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
6335 printk("# MAY BE MISSING FUNCTION EVENTS\n");
6339 * We need to stop all tracing on all CPUS to read the
6340 * the next buffer. This is a bit expensive, but is
6341 * not done often. We fill all what we can read,
6342 * and then release the locks again.
6345 while (!trace_empty(&iter)) {
6348 printk(KERN_TRACE "---------------------------------\n");
6352 /* reset all but tr, trace, and overruns */
6353 memset(&iter.seq, 0,
6354 sizeof(struct trace_iterator) -
6355 offsetof(struct trace_iterator, seq));
6356 iter.iter_flags |= TRACE_FILE_LAT_FMT;
6359 if (trace_find_next_entry_inc(&iter) != NULL) {
6362 ret = print_trace_line(&iter);
6363 if (ret != TRACE_TYPE_NO_CONSUME)
6364 trace_consume(&iter);
6366 touch_nmi_watchdog();
6368 trace_printk_seq(&iter.seq);
6372 printk(KERN_TRACE " (ftrace buffer empty)\n");
6374 printk(KERN_TRACE "---------------------------------\n");
6377 trace_flags |= old_userobj;
6379 for_each_tracing_cpu(cpu) {
6380 atomic_dec(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
6382 atomic_dec(&dump_running);
6383 local_irq_restore(flags);
6385 EXPORT_SYMBOL_GPL(ftrace_dump);
6387 __init static int tracer_alloc_buffers(void)
6393 if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
6396 if (!alloc_cpumask_var(&tracing_cpumask, GFP_KERNEL))
6397 goto out_free_buffer_mask;
6399 /* Only allocate trace_printk buffers if a trace_printk exists */
6400 if (__stop___trace_bprintk_fmt != __start___trace_bprintk_fmt)
6401 /* Must be called before global_trace.buffer is allocated */
6402 trace_printk_init_buffers();
6404 /* To save memory, keep the ring buffer size to its minimum */
6405 if (ring_buffer_expanded)
6406 ring_buf_size = trace_buf_size;
6410 cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
6411 cpumask_copy(tracing_cpumask, cpu_all_mask);
6413 raw_spin_lock_init(&global_trace.start_lock);
6415 /* TODO: make the number of buffers hot pluggable with CPUS */
6416 if (allocate_trace_buffers(&global_trace, ring_buf_size) < 0) {
6417 printk(KERN_ERR "tracer: failed to allocate ring buffer!\n");
6419 goto out_free_cpumask;
6422 if (global_trace.buffer_disabled)
6425 trace_init_cmdlines();
6428 * register_tracer() might reference current_trace, so it
6429 * needs to be set before we register anything. This is
6430 * just a bootstrap of current_trace anyway.
6432 global_trace.current_trace = &nop_trace;
6434 register_tracer(&nop_trace);
6436 /* All seems OK, enable tracing */
6437 tracing_disabled = 0;
6439 atomic_notifier_chain_register(&panic_notifier_list,
6440 &trace_panic_notifier);
6442 register_die_notifier(&trace_die_notifier);
6444 global_trace.flags = TRACE_ARRAY_FL_GLOBAL;
6446 /* Holder for file callbacks */
6447 global_trace.trace_cpu.cpu = RING_BUFFER_ALL_CPUS;
6448 global_trace.trace_cpu.tr = &global_trace;
6450 INIT_LIST_HEAD(&global_trace.systems);
6451 INIT_LIST_HEAD(&global_trace.events);
6452 list_add(&global_trace.list, &ftrace_trace_arrays);
6454 while (trace_boot_options) {
6457 option = strsep(&trace_boot_options, ",");
6458 trace_set_options(&global_trace, option);
6461 register_snapshot_cmd();
6466 free_percpu(global_trace.trace_buffer.data);
6467 #ifdef CONFIG_TRACER_MAX_TRACE
6468 free_percpu(global_trace.max_buffer.data);
6470 free_cpumask_var(tracing_cpumask);
6471 out_free_buffer_mask:
6472 free_cpumask_var(tracing_buffer_mask);
6477 __init static int clear_boot_tracer(void)
6480 * The default tracer at boot buffer is an init section.
6481 * This function is called in lateinit. If we did not
6482 * find the boot tracer, then clear it out, to prevent
6483 * later registration from accessing the buffer that is
6484 * about to be freed.
6486 if (!default_bootup_tracer)
6489 printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n",
6490 default_bootup_tracer);
6491 default_bootup_tracer = NULL;
6496 early_initcall(tracer_alloc_buffers);
6497 fs_initcall(tracer_init_debugfs);
6498 late_initcall(clear_boot_tracer);