2 * ring buffer based function tracer
4 * Copyright (C) 2007-2008 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 William Lee Irwin III
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>
43 #include "trace_output.h"
46 * On boot up, the ring buffer is set to the minimum size, so that
47 * we do not waste memory on systems that are not using tracing.
49 int ring_buffer_expanded;
52 * We need to change this state when a selftest is running.
53 * A selftest will lurk into the ring-buffer to count the
54 * entries inserted during the selftest although some concurrent
55 * insertions into the ring-buffer such as trace_printk could occurred
56 * at the same time, giving false positive or negative results.
58 static bool __read_mostly tracing_selftest_running;
61 * If a tracer is running, we do not want to run SELFTEST.
63 bool __read_mostly tracing_selftest_disabled;
65 /* For tracers that don't implement custom flags */
66 static struct tracer_opt dummy_tracer_opt[] = {
70 static struct tracer_flags dummy_tracer_flags = {
72 .opts = dummy_tracer_opt
75 static int dummy_set_flag(u32 old_flags, u32 bit, int set)
81 * Kill all tracing for good (never come back).
82 * It is initialized to 1 but will turn to zero if the initialization
83 * of the tracer is successful. But that is the only place that sets
86 static int tracing_disabled = 1;
88 DEFINE_PER_CPU(int, ftrace_cpu_disabled);
90 static inline void ftrace_disable_cpu(void)
93 __this_cpu_inc(ftrace_cpu_disabled);
96 static inline void ftrace_enable_cpu(void)
98 __this_cpu_dec(ftrace_cpu_disabled);
102 cpumask_var_t __read_mostly tracing_buffer_mask;
105 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
107 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
108 * is set, then ftrace_dump is called. This will output the contents
109 * of the ftrace buffers to the console. This is very useful for
110 * capturing traces that lead to crashes and outputing it to a
113 * It is default off, but you can enable it with either specifying
114 * "ftrace_dump_on_oops" in the kernel command line, or setting
115 * /proc/sys/kernel/ftrace_dump_on_oops
116 * Set 1 if you want to dump buffers of all CPUs
117 * Set 2 if you want to dump the buffer of the CPU that triggered oops
120 enum ftrace_dump_mode ftrace_dump_on_oops;
122 static int tracing_set_tracer(const char *buf);
124 #define MAX_TRACER_SIZE 100
125 static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata;
126 static char *default_bootup_tracer;
128 static int __init set_cmdline_ftrace(char *str)
130 strncpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
131 default_bootup_tracer = bootup_tracer_buf;
132 /* We are using ftrace early, expand it */
133 ring_buffer_expanded = 1;
136 __setup("ftrace=", set_cmdline_ftrace);
138 static int __init set_ftrace_dump_on_oops(char *str)
140 if (*str++ != '=' || !*str) {
141 ftrace_dump_on_oops = DUMP_ALL;
145 if (!strcmp("orig_cpu", str)) {
146 ftrace_dump_on_oops = DUMP_ORIG;
152 __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
154 unsigned long long ns2usecs(cycle_t nsec)
162 * The global_trace is the descriptor that holds the tracing
163 * buffers for the live tracing. For each CPU, it contains
164 * a link list of pages that will store trace entries. The
165 * page descriptor of the pages in the memory is used to hold
166 * the link list by linking the lru item in the page descriptor
167 * to each of the pages in the buffer per CPU.
169 * For each active CPU there is a data field that holds the
170 * pages for the buffer for that CPU. Each CPU has the same number
171 * of pages allocated for its buffer.
173 static struct trace_array global_trace;
175 static DEFINE_PER_CPU(struct trace_array_cpu, global_trace_cpu);
177 int filter_current_check_discard(struct ring_buffer *buffer,
178 struct ftrace_event_call *call, void *rec,
179 struct ring_buffer_event *event)
181 return filter_check_discard(call, rec, buffer, event);
183 EXPORT_SYMBOL_GPL(filter_current_check_discard);
185 cycle_t ftrace_now(int cpu)
189 /* Early boot up does not have a buffer yet */
190 if (!global_trace.buffer)
191 return trace_clock_local();
193 ts = ring_buffer_time_stamp(global_trace.buffer, cpu);
194 ring_buffer_normalize_time_stamp(global_trace.buffer, cpu, &ts);
200 * The max_tr is used to snapshot the global_trace when a maximum
201 * latency is reached. Some tracers will use this to store a maximum
202 * trace while it continues examining live traces.
204 * The buffers for the max_tr are set up the same as the global_trace.
205 * When a snapshot is taken, the link list of the max_tr is swapped
206 * with the link list of the global_trace and the buffers are reset for
207 * the global_trace so the tracing can continue.
209 static struct trace_array max_tr;
211 static DEFINE_PER_CPU(struct trace_array_cpu, max_tr_data);
213 /* tracer_enabled is used to toggle activation of a tracer */
214 static int tracer_enabled = 1;
217 * tracing_is_enabled - return tracer_enabled status
219 * This function is used by other tracers to know the status
220 * of the tracer_enabled flag. Tracers may use this function
221 * to know if it should enable their features when starting
222 * up. See irqsoff tracer for an example (start_irqsoff_tracer).
224 int tracing_is_enabled(void)
226 return tracer_enabled;
230 * trace_buf_size is the size in bytes that is allocated
231 * for a buffer. Note, the number of bytes is always rounded
234 * This number is purposely set to a low number of 16384.
235 * If the dump on oops happens, it will be much appreciated
236 * to not have to wait for all that output. Anyway this can be
237 * boot time and run time configurable.
239 #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
241 static unsigned long trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
243 /* trace_types holds a link list of available tracers. */
244 static struct tracer *trace_types __read_mostly;
246 /* current_trace points to the tracer that is currently active */
247 static struct tracer *current_trace __read_mostly;
250 * trace_types_lock is used to protect the trace_types list.
252 static DEFINE_MUTEX(trace_types_lock);
255 * serialize the access of the ring buffer
257 * ring buffer serializes readers, but it is low level protection.
258 * The validity of the events (which returns by ring_buffer_peek() ..etc)
259 * are not protected by ring buffer.
261 * The content of events may become garbage if we allow other process consumes
262 * these events concurrently:
263 * A) the page of the consumed events may become a normal page
264 * (not reader page) in ring buffer, and this page will be rewrited
265 * by events producer.
266 * B) The page of the consumed events may become a page for splice_read,
267 * and this page will be returned to system.
269 * These primitives allow multi process access to different cpu ring buffer
272 * These primitives don't distinguish read-only and read-consume access.
273 * Multi read-only access are also serialized.
277 static DECLARE_RWSEM(all_cpu_access_lock);
278 static DEFINE_PER_CPU(struct mutex, cpu_access_lock);
280 static inline void trace_access_lock(int cpu)
282 if (cpu == TRACE_PIPE_ALL_CPU) {
283 /* gain it for accessing the whole ring buffer. */
284 down_write(&all_cpu_access_lock);
286 /* gain it for accessing a cpu ring buffer. */
288 /* Firstly block other trace_access_lock(TRACE_PIPE_ALL_CPU). */
289 down_read(&all_cpu_access_lock);
291 /* Secondly block other access to this @cpu ring buffer. */
292 mutex_lock(&per_cpu(cpu_access_lock, cpu));
296 static inline void trace_access_unlock(int cpu)
298 if (cpu == TRACE_PIPE_ALL_CPU) {
299 up_write(&all_cpu_access_lock);
301 mutex_unlock(&per_cpu(cpu_access_lock, cpu));
302 up_read(&all_cpu_access_lock);
306 static inline void trace_access_lock_init(void)
310 for_each_possible_cpu(cpu)
311 mutex_init(&per_cpu(cpu_access_lock, cpu));
316 static DEFINE_MUTEX(access_lock);
318 static inline void trace_access_lock(int cpu)
321 mutex_lock(&access_lock);
324 static inline void trace_access_unlock(int cpu)
327 mutex_unlock(&access_lock);
330 static inline void trace_access_lock_init(void)
336 /* trace_wait is a waitqueue for tasks blocked on trace_poll */
337 static DECLARE_WAIT_QUEUE_HEAD(trace_wait);
339 /* trace_flags holds trace_options default values */
340 unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK |
341 TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | TRACE_ITER_SLEEP_TIME |
342 TRACE_ITER_GRAPH_TIME | TRACE_ITER_RECORD_CMD | TRACE_ITER_OVERWRITE |
345 static int trace_stop_count;
346 static DEFINE_RAW_SPINLOCK(tracing_start_lock);
348 static void wakeup_work_handler(struct work_struct *work)
350 wake_up(&trace_wait);
353 static DECLARE_DELAYED_WORK(wakeup_work, wakeup_work_handler);
356 * tracing_on - enable tracing buffers
358 * This function enables tracing buffers that may have been
359 * disabled with tracing_off.
361 void tracing_on(void)
363 if (global_trace.buffer)
364 ring_buffer_record_on(global_trace.buffer);
366 * This flag is only looked at when buffers haven't been
367 * allocated yet. We don't really care about the race
368 * between setting this flag and actually turning
371 global_trace.buffer_disabled = 0;
373 EXPORT_SYMBOL_GPL(tracing_on);
376 * tracing_off - turn off tracing buffers
378 * This function stops the tracing buffers from recording data.
379 * It does not disable any overhead the tracers themselves may
380 * be causing. This function simply causes all recording to
381 * the ring buffers to fail.
383 void tracing_off(void)
385 if (global_trace.buffer)
386 ring_buffer_record_on(global_trace.buffer);
388 * This flag is only looked at when buffers haven't been
389 * allocated yet. We don't really care about the race
390 * between setting this flag and actually turning
393 global_trace.buffer_disabled = 1;
395 EXPORT_SYMBOL_GPL(tracing_off);
398 * tracing_is_on - show state of ring buffers enabled
400 int tracing_is_on(void)
402 if (global_trace.buffer)
403 return ring_buffer_record_is_on(global_trace.buffer);
404 return !global_trace.buffer_disabled;
406 EXPORT_SYMBOL_GPL(tracing_is_on);
409 * trace_wake_up - wake up tasks waiting for trace input
411 * Schedules a delayed work to wake up any task that is blocked on the
412 * trace_wait queue. These is used with trace_poll for tasks polling the
415 void trace_wake_up(void)
417 const unsigned long delay = msecs_to_jiffies(2);
419 if (trace_flags & TRACE_ITER_BLOCK)
421 schedule_delayed_work(&wakeup_work, delay);
424 static int __init set_buf_size(char *str)
426 unsigned long buf_size;
430 buf_size = memparse(str, &str);
431 /* nr_entries can not be zero */
434 trace_buf_size = buf_size;
437 __setup("trace_buf_size=", set_buf_size);
439 static int __init set_tracing_thresh(char *str)
441 unsigned long threshhold;
446 ret = strict_strtoul(str, 0, &threshhold);
449 tracing_thresh = threshhold * 1000;
452 __setup("tracing_thresh=", set_tracing_thresh);
454 unsigned long nsecs_to_usecs(unsigned long nsecs)
459 /* These must match the bit postions in trace_iterator_flags */
460 static const char *trace_options[] = {
492 { trace_clock_local, "local" },
493 { trace_clock_global, "global" },
494 { trace_clock_counter, "counter" },
500 * trace_parser_get_init - gets the buffer for trace parser
502 int trace_parser_get_init(struct trace_parser *parser, int size)
504 memset(parser, 0, sizeof(*parser));
506 parser->buffer = kmalloc(size, GFP_KERNEL);
515 * trace_parser_put - frees the buffer for trace parser
517 void trace_parser_put(struct trace_parser *parser)
519 kfree(parser->buffer);
523 * trace_get_user - reads the user input string separated by space
524 * (matched by isspace(ch))
526 * For each string found the 'struct trace_parser' is updated,
527 * and the function returns.
529 * Returns number of bytes read.
531 * See kernel/trace/trace.h for 'struct trace_parser' details.
533 int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
534 size_t cnt, loff_t *ppos)
541 trace_parser_clear(parser);
543 ret = get_user(ch, ubuf++);
551 * The parser is not finished with the last write,
552 * continue reading the user input without skipping spaces.
555 /* skip white space */
556 while (cnt && isspace(ch)) {
557 ret = get_user(ch, ubuf++);
564 /* only spaces were written */
574 /* read the non-space input */
575 while (cnt && !isspace(ch)) {
576 if (parser->idx < parser->size - 1)
577 parser->buffer[parser->idx++] = ch;
582 ret = get_user(ch, ubuf++);
589 /* We either got finished input or we have to wait for another call. */
591 parser->buffer[parser->idx] = 0;
592 parser->cont = false;
595 parser->buffer[parser->idx++] = ch;
605 ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
613 if (s->len <= s->readpos)
616 len = s->len - s->readpos;
619 ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
629 static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
634 if (s->len <= s->readpos)
637 len = s->len - s->readpos;
640 ret = memcpy(buf, s->buffer + s->readpos, cnt);
649 * ftrace_max_lock is used to protect the swapping of buffers
650 * when taking a max snapshot. The buffers themselves are
651 * protected by per_cpu spinlocks. But the action of the swap
652 * needs its own lock.
654 * This is defined as a arch_spinlock_t in order to help
655 * with performance when lockdep debugging is enabled.
657 * It is also used in other places outside the update_max_tr
658 * so it needs to be defined outside of the
659 * CONFIG_TRACER_MAX_TRACE.
661 static arch_spinlock_t ftrace_max_lock =
662 (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
664 unsigned long __read_mostly tracing_thresh;
666 #ifdef CONFIG_TRACER_MAX_TRACE
667 unsigned long __read_mostly tracing_max_latency;
670 * Copy the new maximum trace into the separate maximum-trace
671 * structure. (this way the maximum trace is permanently saved,
672 * for later retrieval via /sys/kernel/debug/tracing/latency_trace)
675 __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
677 struct trace_array_cpu *data = tr->data[cpu];
678 struct trace_array_cpu *max_data;
681 max_tr.time_start = data->preempt_timestamp;
683 max_data = max_tr.data[cpu];
684 max_data->saved_latency = tracing_max_latency;
685 max_data->critical_start = data->critical_start;
686 max_data->critical_end = data->critical_end;
688 memcpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
689 max_data->pid = tsk->pid;
690 max_data->uid = task_uid(tsk);
691 max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
692 max_data->policy = tsk->policy;
693 max_data->rt_priority = tsk->rt_priority;
695 /* record this tasks comm */
696 tracing_record_cmdline(tsk);
700 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
702 * @tsk: the task with the latency
703 * @cpu: The cpu that initiated the trace.
705 * Flip the buffers between the @tr and the max_tr and record information
706 * about which task was the cause of this latency.
709 update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
711 struct ring_buffer *buf = tr->buffer;
713 if (trace_stop_count)
716 WARN_ON_ONCE(!irqs_disabled());
717 if (!current_trace->use_max_tr) {
721 arch_spin_lock(&ftrace_max_lock);
723 tr->buffer = max_tr.buffer;
726 __update_max_tr(tr, tsk, cpu);
727 arch_spin_unlock(&ftrace_max_lock);
731 * update_max_tr_single - only copy one trace over, and reset the rest
733 * @tsk - task with the latency
734 * @cpu - the cpu of the buffer to copy.
736 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
739 update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
743 if (trace_stop_count)
746 WARN_ON_ONCE(!irqs_disabled());
747 if (!current_trace->use_max_tr) {
752 arch_spin_lock(&ftrace_max_lock);
754 ftrace_disable_cpu();
756 ret = ring_buffer_swap_cpu(max_tr.buffer, tr->buffer, cpu);
760 * We failed to swap the buffer due to a commit taking
761 * place on this CPU. We fail to record, but we reset
762 * the max trace buffer (no one writes directly to it)
763 * and flag that it failed.
765 trace_array_printk(&max_tr, _THIS_IP_,
766 "Failed to swap buffers due to commit in progress\n");
771 WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);
773 __update_max_tr(tr, tsk, cpu);
774 arch_spin_unlock(&ftrace_max_lock);
776 #endif /* CONFIG_TRACER_MAX_TRACE */
779 * register_tracer - register a tracer with the ftrace system.
780 * @type - the plugin for the tracer
782 * Register a new plugin tracer.
784 int register_tracer(struct tracer *type)
785 __releases(kernel_lock)
786 __acquires(kernel_lock)
792 pr_info("Tracer must have a name\n");
796 if (strlen(type->name) >= MAX_TRACER_SIZE) {
797 pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE);
801 mutex_lock(&trace_types_lock);
803 tracing_selftest_running = true;
805 for (t = trace_types; t; t = t->next) {
806 if (strcmp(type->name, t->name) == 0) {
808 pr_info("Tracer %s already registered\n",
816 type->set_flag = &dummy_set_flag;
818 type->flags = &dummy_tracer_flags;
820 if (!type->flags->opts)
821 type->flags->opts = dummy_tracer_opt;
822 if (!type->wait_pipe)
823 type->wait_pipe = default_wait_pipe;
826 #ifdef CONFIG_FTRACE_STARTUP_TEST
827 if (type->selftest && !tracing_selftest_disabled) {
828 struct tracer *saved_tracer = current_trace;
829 struct trace_array *tr = &global_trace;
832 * Run a selftest on this tracer.
833 * Here we reset the trace buffer, and set the current
834 * tracer to be this tracer. The tracer can then run some
835 * internal tracing to verify that everything is in order.
836 * If we fail, we do not register this tracer.
838 tracing_reset_online_cpus(tr);
840 current_trace = type;
842 /* If we expanded the buffers, make sure the max is expanded too */
843 if (ring_buffer_expanded && type->use_max_tr)
844 ring_buffer_resize(max_tr.buffer, trace_buf_size);
846 /* the test is responsible for initializing and enabling */
847 pr_info("Testing tracer %s: ", type->name);
848 ret = type->selftest(type, tr);
849 /* the test is responsible for resetting too */
850 current_trace = saved_tracer;
852 printk(KERN_CONT "FAILED!\n");
855 /* Only reset on passing, to avoid touching corrupted buffers */
856 tracing_reset_online_cpus(tr);
858 /* Shrink the max buffer again */
859 if (ring_buffer_expanded && type->use_max_tr)
860 ring_buffer_resize(max_tr.buffer, 1);
862 printk(KERN_CONT "PASSED\n");
866 type->next = trace_types;
870 tracing_selftest_running = false;
871 mutex_unlock(&trace_types_lock);
873 if (ret || !default_bootup_tracer)
876 if (strncmp(default_bootup_tracer, type->name, MAX_TRACER_SIZE))
879 printk(KERN_INFO "Starting tracer '%s'\n", type->name);
880 /* Do we want this tracer to start on bootup? */
881 tracing_set_tracer(type->name);
882 default_bootup_tracer = NULL;
883 /* disable other selftests, since this will break it. */
884 tracing_selftest_disabled = 1;
885 #ifdef CONFIG_FTRACE_STARTUP_TEST
886 printk(KERN_INFO "Disabling FTRACE selftests due to running tracer '%s'\n",
894 void unregister_tracer(struct tracer *type)
898 mutex_lock(&trace_types_lock);
899 for (t = &trace_types; *t; t = &(*t)->next) {
903 pr_info("Tracer %s not registered\n", type->name);
909 if (type == current_trace && tracer_enabled) {
912 if (current_trace->stop)
913 current_trace->stop(&global_trace);
914 current_trace = &nop_trace;
917 mutex_unlock(&trace_types_lock);
920 static void __tracing_reset(struct ring_buffer *buffer, int cpu)
922 ftrace_disable_cpu();
923 ring_buffer_reset_cpu(buffer, cpu);
927 void tracing_reset(struct trace_array *tr, int cpu)
929 struct ring_buffer *buffer = tr->buffer;
931 ring_buffer_record_disable(buffer);
933 /* Make sure all commits have finished */
935 __tracing_reset(buffer, cpu);
937 ring_buffer_record_enable(buffer);
940 void tracing_reset_online_cpus(struct trace_array *tr)
942 struct ring_buffer *buffer = tr->buffer;
945 ring_buffer_record_disable(buffer);
947 /* Make sure all commits have finished */
950 tr->time_start = ftrace_now(tr->cpu);
952 for_each_online_cpu(cpu)
953 __tracing_reset(buffer, cpu);
955 ring_buffer_record_enable(buffer);
958 void tracing_reset_current(int cpu)
960 tracing_reset(&global_trace, cpu);
963 void tracing_reset_current_online_cpus(void)
965 tracing_reset_online_cpus(&global_trace);
968 #define SAVED_CMDLINES 128
969 #define NO_CMDLINE_MAP UINT_MAX
970 static unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
971 static unsigned map_cmdline_to_pid[SAVED_CMDLINES];
972 static char saved_cmdlines[SAVED_CMDLINES][TASK_COMM_LEN];
973 static int cmdline_idx;
974 static arch_spinlock_t trace_cmdline_lock = __ARCH_SPIN_LOCK_UNLOCKED;
976 /* temporary disable recording */
977 static atomic_t trace_record_cmdline_disabled __read_mostly;
979 static void trace_init_cmdlines(void)
981 memset(&map_pid_to_cmdline, NO_CMDLINE_MAP, sizeof(map_pid_to_cmdline));
982 memset(&map_cmdline_to_pid, NO_CMDLINE_MAP, sizeof(map_cmdline_to_pid));
986 int is_tracing_stopped(void)
988 return trace_stop_count;
992 * ftrace_off_permanent - disable all ftrace code permanently
994 * This should only be called when a serious anomally has
995 * been detected. This will turn off the function tracing,
996 * ring buffers, and other tracing utilites. It takes no
997 * locks and can be called from any context.
999 void ftrace_off_permanent(void)
1001 tracing_disabled = 1;
1003 tracing_off_permanent();
1007 * tracing_start - quick start of the tracer
1009 * If tracing is enabled but was stopped by tracing_stop,
1010 * this will start the tracer back up.
1012 void tracing_start(void)
1014 struct ring_buffer *buffer;
1015 unsigned long flags;
1017 if (tracing_disabled)
1020 raw_spin_lock_irqsave(&tracing_start_lock, flags);
1021 if (--trace_stop_count) {
1022 if (trace_stop_count < 0) {
1023 /* Someone screwed up their debugging */
1025 trace_stop_count = 0;
1030 /* Prevent the buffers from switching */
1031 arch_spin_lock(&ftrace_max_lock);
1033 buffer = global_trace.buffer;
1035 ring_buffer_record_enable(buffer);
1037 buffer = max_tr.buffer;
1039 ring_buffer_record_enable(buffer);
1041 arch_spin_unlock(&ftrace_max_lock);
1045 raw_spin_unlock_irqrestore(&tracing_start_lock, flags);
1049 * tracing_stop - quick stop of the tracer
1051 * Light weight way to stop tracing. Use in conjunction with
1054 void tracing_stop(void)
1056 struct ring_buffer *buffer;
1057 unsigned long flags;
1060 raw_spin_lock_irqsave(&tracing_start_lock, flags);
1061 if (trace_stop_count++)
1064 /* Prevent the buffers from switching */
1065 arch_spin_lock(&ftrace_max_lock);
1067 buffer = global_trace.buffer;
1069 ring_buffer_record_disable(buffer);
1071 buffer = max_tr.buffer;
1073 ring_buffer_record_disable(buffer);
1075 arch_spin_unlock(&ftrace_max_lock);
1078 raw_spin_unlock_irqrestore(&tracing_start_lock, flags);
1081 void trace_stop_cmdline_recording(void);
1083 static void trace_save_cmdline(struct task_struct *tsk)
1087 if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT))
1091 * It's not the end of the world if we don't get
1092 * the lock, but we also don't want to spin
1093 * nor do we want to disable interrupts,
1094 * so if we miss here, then better luck next time.
1096 if (!arch_spin_trylock(&trace_cmdline_lock))
1099 idx = map_pid_to_cmdline[tsk->pid];
1100 if (idx == NO_CMDLINE_MAP) {
1101 idx = (cmdline_idx + 1) % SAVED_CMDLINES;
1104 * Check whether the cmdline buffer at idx has a pid
1105 * mapped. We are going to overwrite that entry so we
1106 * need to clear the map_pid_to_cmdline. Otherwise we
1107 * would read the new comm for the old pid.
1109 pid = map_cmdline_to_pid[idx];
1110 if (pid != NO_CMDLINE_MAP)
1111 map_pid_to_cmdline[pid] = NO_CMDLINE_MAP;
1113 map_cmdline_to_pid[idx] = tsk->pid;
1114 map_pid_to_cmdline[tsk->pid] = idx;
1119 memcpy(&saved_cmdlines[idx], tsk->comm, TASK_COMM_LEN);
1121 arch_spin_unlock(&trace_cmdline_lock);
1124 void trace_find_cmdline(int pid, char comm[])
1129 strcpy(comm, "<idle>");
1133 if (WARN_ON_ONCE(pid < 0)) {
1134 strcpy(comm, "<XXX>");
1138 if (pid > PID_MAX_DEFAULT) {
1139 strcpy(comm, "<...>");
1144 arch_spin_lock(&trace_cmdline_lock);
1145 map = map_pid_to_cmdline[pid];
1146 if (map != NO_CMDLINE_MAP)
1147 strcpy(comm, saved_cmdlines[map]);
1149 strcpy(comm, "<...>");
1151 arch_spin_unlock(&trace_cmdline_lock);
1155 void tracing_record_cmdline(struct task_struct *tsk)
1157 if (atomic_read(&trace_record_cmdline_disabled) || !tracer_enabled ||
1161 trace_save_cmdline(tsk);
1165 tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
1168 struct task_struct *tsk = current;
1170 entry->preempt_count = pc & 0xff;
1171 entry->pid = (tsk) ? tsk->pid : 0;
1174 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
1175 (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
1177 TRACE_FLAG_IRQS_NOSUPPORT |
1179 ((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
1180 ((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
1181 (need_resched() ? TRACE_FLAG_NEED_RESCHED : 0);
1183 EXPORT_SYMBOL_GPL(tracing_generic_entry_update);
1185 struct ring_buffer_event *
1186 trace_buffer_lock_reserve(struct ring_buffer *buffer,
1189 unsigned long flags, int pc)
1191 struct ring_buffer_event *event;
1193 event = ring_buffer_lock_reserve(buffer, len);
1194 if (event != NULL) {
1195 struct trace_entry *ent = ring_buffer_event_data(event);
1197 tracing_generic_entry_update(ent, flags, pc);
1205 __trace_buffer_unlock_commit(struct ring_buffer *buffer,
1206 struct ring_buffer_event *event,
1207 unsigned long flags, int pc,
1210 ring_buffer_unlock_commit(buffer, event);
1212 ftrace_trace_stack(buffer, flags, 6, pc);
1213 ftrace_trace_userstack(buffer, flags, pc);
1219 void trace_buffer_unlock_commit(struct ring_buffer *buffer,
1220 struct ring_buffer_event *event,
1221 unsigned long flags, int pc)
1223 __trace_buffer_unlock_commit(buffer, event, flags, pc, 1);
1226 struct ring_buffer_event *
1227 trace_current_buffer_lock_reserve(struct ring_buffer **current_rb,
1228 int type, unsigned long len,
1229 unsigned long flags, int pc)
1231 *current_rb = global_trace.buffer;
1232 return trace_buffer_lock_reserve(*current_rb,
1233 type, len, flags, pc);
1235 EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve);
1237 void trace_current_buffer_unlock_commit(struct ring_buffer *buffer,
1238 struct ring_buffer_event *event,
1239 unsigned long flags, int pc)
1241 __trace_buffer_unlock_commit(buffer, event, flags, pc, 1);
1243 EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit);
1245 void trace_nowake_buffer_unlock_commit(struct ring_buffer *buffer,
1246 struct ring_buffer_event *event,
1247 unsigned long flags, int pc)
1249 __trace_buffer_unlock_commit(buffer, event, flags, pc, 0);
1251 EXPORT_SYMBOL_GPL(trace_nowake_buffer_unlock_commit);
1253 void trace_nowake_buffer_unlock_commit_regs(struct ring_buffer *buffer,
1254 struct ring_buffer_event *event,
1255 unsigned long flags, int pc,
1256 struct pt_regs *regs)
1258 ring_buffer_unlock_commit(buffer, event);
1260 ftrace_trace_stack_regs(buffer, flags, 0, pc, regs);
1261 ftrace_trace_userstack(buffer, flags, pc);
1263 EXPORT_SYMBOL_GPL(trace_nowake_buffer_unlock_commit_regs);
1265 void trace_current_buffer_discard_commit(struct ring_buffer *buffer,
1266 struct ring_buffer_event *event)
1268 ring_buffer_discard_commit(buffer, event);
1270 EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit);
1273 trace_function(struct trace_array *tr,
1274 unsigned long ip, unsigned long parent_ip, unsigned long flags,
1277 struct ftrace_event_call *call = &event_function;
1278 struct ring_buffer *buffer = tr->buffer;
1279 struct ring_buffer_event *event;
1280 struct ftrace_entry *entry;
1282 /* If we are reading the ring buffer, don't trace */
1283 if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))
1286 event = trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
1290 entry = ring_buffer_event_data(event);
1292 entry->parent_ip = parent_ip;
1294 if (!filter_check_discard(call, entry, buffer, event))
1295 ring_buffer_unlock_commit(buffer, event);
1299 ftrace(struct trace_array *tr, struct trace_array_cpu *data,
1300 unsigned long ip, unsigned long parent_ip, unsigned long flags,
1303 if (likely(!atomic_read(&data->disabled)))
1304 trace_function(tr, ip, parent_ip, flags, pc);
1307 #ifdef CONFIG_STACKTRACE
1309 #define FTRACE_STACK_MAX_ENTRIES (PAGE_SIZE / sizeof(unsigned long))
1310 struct ftrace_stack {
1311 unsigned long calls[FTRACE_STACK_MAX_ENTRIES];
1314 static DEFINE_PER_CPU(struct ftrace_stack, ftrace_stack);
1315 static DEFINE_PER_CPU(int, ftrace_stack_reserve);
1317 static void __ftrace_trace_stack(struct ring_buffer *buffer,
1318 unsigned long flags,
1319 int skip, int pc, struct pt_regs *regs)
1321 struct ftrace_event_call *call = &event_kernel_stack;
1322 struct ring_buffer_event *event;
1323 struct stack_entry *entry;
1324 struct stack_trace trace;
1326 int size = FTRACE_STACK_ENTRIES;
1328 trace.nr_entries = 0;
1332 * Since events can happen in NMIs there's no safe way to
1333 * use the per cpu ftrace_stacks. We reserve it and if an interrupt
1334 * or NMI comes in, it will just have to use the default
1335 * FTRACE_STACK_SIZE.
1337 preempt_disable_notrace();
1339 use_stack = ++__get_cpu_var(ftrace_stack_reserve);
1341 * We don't need any atomic variables, just a barrier.
1342 * If an interrupt comes in, we don't care, because it would
1343 * have exited and put the counter back to what we want.
1344 * We just need a barrier to keep gcc from moving things
1348 if (use_stack == 1) {
1349 trace.entries = &__get_cpu_var(ftrace_stack).calls[0];
1350 trace.max_entries = FTRACE_STACK_MAX_ENTRIES;
1353 save_stack_trace_regs(regs, &trace);
1355 save_stack_trace(&trace);
1357 if (trace.nr_entries > size)
1358 size = trace.nr_entries;
1360 /* From now on, use_stack is a boolean */
1363 size *= sizeof(unsigned long);
1365 event = trace_buffer_lock_reserve(buffer, TRACE_STACK,
1366 sizeof(*entry) + size, flags, pc);
1369 entry = ring_buffer_event_data(event);
1371 memset(&entry->caller, 0, size);
1374 memcpy(&entry->caller, trace.entries,
1375 trace.nr_entries * sizeof(unsigned long));
1377 trace.max_entries = FTRACE_STACK_ENTRIES;
1378 trace.entries = entry->caller;
1380 save_stack_trace_regs(regs, &trace);
1382 save_stack_trace(&trace);
1385 entry->size = trace.nr_entries;
1387 if (!filter_check_discard(call, entry, buffer, event))
1388 ring_buffer_unlock_commit(buffer, event);
1391 /* Again, don't let gcc optimize things here */
1393 __get_cpu_var(ftrace_stack_reserve)--;
1394 preempt_enable_notrace();
1398 void ftrace_trace_stack_regs(struct ring_buffer *buffer, unsigned long flags,
1399 int skip, int pc, struct pt_regs *regs)
1401 if (!(trace_flags & TRACE_ITER_STACKTRACE))
1404 __ftrace_trace_stack(buffer, flags, skip, pc, regs);
1407 void ftrace_trace_stack(struct ring_buffer *buffer, unsigned long flags,
1410 if (!(trace_flags & TRACE_ITER_STACKTRACE))
1413 __ftrace_trace_stack(buffer, flags, skip, pc, NULL);
1416 void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
1419 __ftrace_trace_stack(tr->buffer, flags, skip, pc, NULL);
1423 * trace_dump_stack - record a stack back trace in the trace buffer
1425 void trace_dump_stack(void)
1427 unsigned long flags;
1429 if (tracing_disabled || tracing_selftest_running)
1432 local_save_flags(flags);
1434 /* skipping 3 traces, seems to get us at the caller of this function */
1435 __ftrace_trace_stack(global_trace.buffer, flags, 3, preempt_count(), NULL);
1438 static DEFINE_PER_CPU(int, user_stack_count);
1441 ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
1443 struct ftrace_event_call *call = &event_user_stack;
1444 struct ring_buffer_event *event;
1445 struct userstack_entry *entry;
1446 struct stack_trace trace;
1448 if (!(trace_flags & TRACE_ITER_USERSTACKTRACE))
1452 * NMIs can not handle page faults, even with fix ups.
1453 * The save user stack can (and often does) fault.
1455 if (unlikely(in_nmi()))
1459 * prevent recursion, since the user stack tracing may
1460 * trigger other kernel events.
1463 if (__this_cpu_read(user_stack_count))
1466 __this_cpu_inc(user_stack_count);
1468 event = trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
1469 sizeof(*entry), flags, pc);
1471 goto out_drop_count;
1472 entry = ring_buffer_event_data(event);
1474 entry->tgid = current->tgid;
1475 memset(&entry->caller, 0, sizeof(entry->caller));
1477 trace.nr_entries = 0;
1478 trace.max_entries = FTRACE_STACK_ENTRIES;
1480 trace.entries = entry->caller;
1482 save_stack_trace_user(&trace);
1483 if (!filter_check_discard(call, entry, buffer, event))
1484 ring_buffer_unlock_commit(buffer, event);
1487 __this_cpu_dec(user_stack_count);
1493 static void __trace_userstack(struct trace_array *tr, unsigned long flags)
1495 ftrace_trace_userstack(tr, flags, preempt_count());
1499 #endif /* CONFIG_STACKTRACE */
1502 * trace_vbprintk - write binary msg to tracing buffer
1505 int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
1507 static arch_spinlock_t trace_buf_lock =
1508 (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
1509 static u32 trace_buf[TRACE_BUF_SIZE];
1511 struct ftrace_event_call *call = &event_bprint;
1512 struct ring_buffer_event *event;
1513 struct ring_buffer *buffer;
1514 struct trace_array *tr = &global_trace;
1515 struct trace_array_cpu *data;
1516 struct bprint_entry *entry;
1517 unsigned long flags;
1519 int cpu, len = 0, size, pc;
1521 if (unlikely(tracing_selftest_running || tracing_disabled))
1524 /* Don't pollute graph traces with trace_vprintk internals */
1525 pause_graph_tracing();
1527 pc = preempt_count();
1528 preempt_disable_notrace();
1529 cpu = raw_smp_processor_id();
1530 data = tr->data[cpu];
1532 disable = atomic_inc_return(&data->disabled);
1533 if (unlikely(disable != 1))
1536 /* Lockdep uses trace_printk for lock tracing */
1537 local_irq_save(flags);
1538 arch_spin_lock(&trace_buf_lock);
1539 len = vbin_printf(trace_buf, TRACE_BUF_SIZE, fmt, args);
1541 if (len > TRACE_BUF_SIZE || len < 0)
1544 size = sizeof(*entry) + sizeof(u32) * len;
1545 buffer = tr->buffer;
1546 event = trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
1550 entry = ring_buffer_event_data(event);
1554 memcpy(entry->buf, trace_buf, sizeof(u32) * len);
1555 if (!filter_check_discard(call, entry, buffer, event)) {
1556 ring_buffer_unlock_commit(buffer, event);
1557 ftrace_trace_stack(buffer, flags, 6, pc);
1561 arch_spin_unlock(&trace_buf_lock);
1562 local_irq_restore(flags);
1565 atomic_dec_return(&data->disabled);
1566 preempt_enable_notrace();
1567 unpause_graph_tracing();
1571 EXPORT_SYMBOL_GPL(trace_vbprintk);
1573 int trace_array_printk(struct trace_array *tr,
1574 unsigned long ip, const char *fmt, ...)
1579 if (!(trace_flags & TRACE_ITER_PRINTK))
1583 ret = trace_array_vprintk(tr, ip, fmt, ap);
1588 int trace_array_vprintk(struct trace_array *tr,
1589 unsigned long ip, const char *fmt, va_list args)
1591 static arch_spinlock_t trace_buf_lock = __ARCH_SPIN_LOCK_UNLOCKED;
1592 static char trace_buf[TRACE_BUF_SIZE];
1594 struct ftrace_event_call *call = &event_print;
1595 struct ring_buffer_event *event;
1596 struct ring_buffer *buffer;
1597 struct trace_array_cpu *data;
1598 int cpu, len = 0, size, pc;
1599 struct print_entry *entry;
1600 unsigned long irq_flags;
1603 if (tracing_disabled || tracing_selftest_running)
1606 pc = preempt_count();
1607 preempt_disable_notrace();
1608 cpu = raw_smp_processor_id();
1609 data = tr->data[cpu];
1611 disable = atomic_inc_return(&data->disabled);
1612 if (unlikely(disable != 1))
1615 pause_graph_tracing();
1616 raw_local_irq_save(irq_flags);
1617 arch_spin_lock(&trace_buf_lock);
1618 len = vsnprintf(trace_buf, TRACE_BUF_SIZE, fmt, args);
1620 size = sizeof(*entry) + len + 1;
1621 buffer = tr->buffer;
1622 event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
1626 entry = ring_buffer_event_data(event);
1629 memcpy(&entry->buf, trace_buf, len);
1630 entry->buf[len] = '\0';
1631 if (!filter_check_discard(call, entry, buffer, event)) {
1632 ring_buffer_unlock_commit(buffer, event);
1633 ftrace_trace_stack(buffer, irq_flags, 6, pc);
1637 arch_spin_unlock(&trace_buf_lock);
1638 raw_local_irq_restore(irq_flags);
1639 unpause_graph_tracing();
1641 atomic_dec_return(&data->disabled);
1642 preempt_enable_notrace();
1647 int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
1649 return trace_array_vprintk(&global_trace, ip, fmt, args);
1651 EXPORT_SYMBOL_GPL(trace_vprintk);
1653 static void trace_iterator_increment(struct trace_iterator *iter)
1655 /* Don't allow ftrace to trace into the ring buffers */
1656 ftrace_disable_cpu();
1659 if (iter->buffer_iter[iter->cpu])
1660 ring_buffer_read(iter->buffer_iter[iter->cpu], NULL);
1662 ftrace_enable_cpu();
1665 static struct trace_entry *
1666 peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts,
1667 unsigned long *lost_events)
1669 struct ring_buffer_event *event;
1670 struct ring_buffer_iter *buf_iter = iter->buffer_iter[cpu];
1672 /* Don't allow ftrace to trace into the ring buffers */
1673 ftrace_disable_cpu();
1676 event = ring_buffer_iter_peek(buf_iter, ts);
1678 event = ring_buffer_peek(iter->tr->buffer, cpu, ts,
1681 ftrace_enable_cpu();
1684 iter->ent_size = ring_buffer_event_length(event);
1685 return ring_buffer_event_data(event);
1691 static struct trace_entry *
1692 __find_next_entry(struct trace_iterator *iter, int *ent_cpu,
1693 unsigned long *missing_events, u64 *ent_ts)
1695 struct ring_buffer *buffer = iter->tr->buffer;
1696 struct trace_entry *ent, *next = NULL;
1697 unsigned long lost_events = 0, next_lost = 0;
1698 int cpu_file = iter->cpu_file;
1699 u64 next_ts = 0, ts;
1705 * If we are in a per_cpu trace file, don't bother by iterating over
1706 * all cpu and peek directly.
1708 if (cpu_file > TRACE_PIPE_ALL_CPU) {
1709 if (ring_buffer_empty_cpu(buffer, cpu_file))
1711 ent = peek_next_entry(iter, cpu_file, ent_ts, missing_events);
1713 *ent_cpu = cpu_file;
1718 for_each_tracing_cpu(cpu) {
1720 if (ring_buffer_empty_cpu(buffer, cpu))
1723 ent = peek_next_entry(iter, cpu, &ts, &lost_events);
1726 * Pick the entry with the smallest timestamp:
1728 if (ent && (!next || ts < next_ts)) {
1732 next_lost = lost_events;
1733 next_size = iter->ent_size;
1737 iter->ent_size = next_size;
1740 *ent_cpu = next_cpu;
1746 *missing_events = next_lost;
1751 /* Find the next real entry, without updating the iterator itself */
1752 struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
1753 int *ent_cpu, u64 *ent_ts)
1755 return __find_next_entry(iter, ent_cpu, NULL, ent_ts);
1758 /* Find the next real entry, and increment the iterator to the next entry */
1759 void *trace_find_next_entry_inc(struct trace_iterator *iter)
1761 iter->ent = __find_next_entry(iter, &iter->cpu,
1762 &iter->lost_events, &iter->ts);
1765 trace_iterator_increment(iter);
1767 return iter->ent ? iter : NULL;
1770 static void trace_consume(struct trace_iterator *iter)
1772 /* Don't allow ftrace to trace into the ring buffers */
1773 ftrace_disable_cpu();
1774 ring_buffer_consume(iter->tr->buffer, iter->cpu, &iter->ts,
1775 &iter->lost_events);
1776 ftrace_enable_cpu();
1779 static void *s_next(struct seq_file *m, void *v, loff_t *pos)
1781 struct trace_iterator *iter = m->private;
1785 WARN_ON_ONCE(iter->leftover);
1789 /* can't go backwards */
1794 ent = trace_find_next_entry_inc(iter);
1798 while (ent && iter->idx < i)
1799 ent = trace_find_next_entry_inc(iter);
1806 void tracing_iter_reset(struct trace_iterator *iter, int cpu)
1808 struct trace_array *tr = iter->tr;
1809 struct ring_buffer_event *event;
1810 struct ring_buffer_iter *buf_iter;
1811 unsigned long entries = 0;
1814 tr->data[cpu]->skipped_entries = 0;
1816 if (!iter->buffer_iter[cpu])
1819 buf_iter = iter->buffer_iter[cpu];
1820 ring_buffer_iter_reset(buf_iter);
1823 * We could have the case with the max latency tracers
1824 * that a reset never took place on a cpu. This is evident
1825 * by the timestamp being before the start of the buffer.
1827 while ((event = ring_buffer_iter_peek(buf_iter, &ts))) {
1828 if (ts >= iter->tr->time_start)
1831 ring_buffer_read(buf_iter, NULL);
1834 tr->data[cpu]->skipped_entries = entries;
1838 * The current tracer is copied to avoid a global locking
1841 static void *s_start(struct seq_file *m, loff_t *pos)
1843 struct trace_iterator *iter = m->private;
1844 static struct tracer *old_tracer;
1845 int cpu_file = iter->cpu_file;
1850 /* copy the tracer to avoid using a global lock all around */
1851 mutex_lock(&trace_types_lock);
1852 if (unlikely(old_tracer != current_trace && current_trace)) {
1853 old_tracer = current_trace;
1854 *iter->trace = *current_trace;
1856 mutex_unlock(&trace_types_lock);
1858 atomic_inc(&trace_record_cmdline_disabled);
1860 if (*pos != iter->pos) {
1865 ftrace_disable_cpu();
1867 if (cpu_file == TRACE_PIPE_ALL_CPU) {
1868 for_each_tracing_cpu(cpu)
1869 tracing_iter_reset(iter, cpu);
1871 tracing_iter_reset(iter, cpu_file);
1873 ftrace_enable_cpu();
1876 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
1881 * If we overflowed the seq_file before, then we want
1882 * to just reuse the trace_seq buffer again.
1888 p = s_next(m, p, &l);
1892 trace_event_read_lock();
1893 trace_access_lock(cpu_file);
1897 static void s_stop(struct seq_file *m, void *p)
1899 struct trace_iterator *iter = m->private;
1901 atomic_dec(&trace_record_cmdline_disabled);
1902 trace_access_unlock(iter->cpu_file);
1903 trace_event_read_unlock();
1907 get_total_entries(struct trace_array *tr, unsigned long *total, unsigned long *entries)
1909 unsigned long count;
1915 for_each_tracing_cpu(cpu) {
1916 count = ring_buffer_entries_cpu(tr->buffer, cpu);
1918 * If this buffer has skipped entries, then we hold all
1919 * entries for the trace and we need to ignore the
1920 * ones before the time stamp.
1922 if (tr->data[cpu]->skipped_entries) {
1923 count -= tr->data[cpu]->skipped_entries;
1924 /* total is the same as the entries */
1928 ring_buffer_overrun_cpu(tr->buffer, cpu);
1933 static void print_lat_help_header(struct seq_file *m)
1935 seq_puts(m, "# _------=> CPU# \n");
1936 seq_puts(m, "# / _-----=> irqs-off \n");
1937 seq_puts(m, "# | / _----=> need-resched \n");
1938 seq_puts(m, "# || / _---=> hardirq/softirq \n");
1939 seq_puts(m, "# ||| / _--=> preempt-depth \n");
1940 seq_puts(m, "# |||| / delay \n");
1941 seq_puts(m, "# cmd pid ||||| time | caller \n");
1942 seq_puts(m, "# \\ / ||||| \\ | / \n");
1945 static void print_event_info(struct trace_array *tr, struct seq_file *m)
1947 unsigned long total;
1948 unsigned long entries;
1950 get_total_entries(tr, &total, &entries);
1951 seq_printf(m, "# entries-in-buffer/entries-written: %lu/%lu #P:%d\n",
1952 entries, total, num_online_cpus());
1956 static void print_func_help_header(struct trace_array *tr, struct seq_file *m)
1958 print_event_info(tr, m);
1959 seq_puts(m, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
1960 seq_puts(m, "# | | | | |\n");
1963 static void print_func_help_header_irq(struct trace_array *tr, struct seq_file *m)
1965 print_event_info(tr, m);
1966 seq_puts(m, "# _-----=> irqs-off\n");
1967 seq_puts(m, "# / _----=> need-resched\n");
1968 seq_puts(m, "# | / _---=> hardirq/softirq\n");
1969 seq_puts(m, "# || / _--=> preempt-depth\n");
1970 seq_puts(m, "# ||| / delay\n");
1971 seq_puts(m, "# TASK-PID CPU# |||| TIMESTAMP FUNCTION\n");
1972 seq_puts(m, "# | | | |||| | |\n");
1976 print_trace_header(struct seq_file *m, struct trace_iterator *iter)
1978 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1979 struct trace_array *tr = iter->tr;
1980 struct trace_array_cpu *data = tr->data[tr->cpu];
1981 struct tracer *type = current_trace;
1982 unsigned long entries;
1983 unsigned long total;
1984 const char *name = "preemption";
1989 get_total_entries(tr, &total, &entries);
1991 seq_printf(m, "# %s latency trace v1.1.5 on %s\n",
1993 seq_puts(m, "# -----------------------------------"
1994 "---------------------------------\n");
1995 seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d |"
1996 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
1997 nsecs_to_usecs(data->saved_latency),
2001 #if defined(CONFIG_PREEMPT_NONE)
2003 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
2005 #elif defined(CONFIG_PREEMPT)
2010 /* These are reserved for later use */
2013 seq_printf(m, " #P:%d)\n", num_online_cpus());
2017 seq_puts(m, "# -----------------\n");
2018 seq_printf(m, "# | task: %.16s-%d "
2019 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
2020 data->comm, data->pid, data->uid, data->nice,
2021 data->policy, data->rt_priority);
2022 seq_puts(m, "# -----------------\n");
2024 if (data->critical_start) {
2025 seq_puts(m, "# => started at: ");
2026 seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
2027 trace_print_seq(m, &iter->seq);
2028 seq_puts(m, "\n# => ended at: ");
2029 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
2030 trace_print_seq(m, &iter->seq);
2031 seq_puts(m, "\n#\n");
2037 static void test_cpu_buff_start(struct trace_iterator *iter)
2039 struct trace_seq *s = &iter->seq;
2041 if (!(trace_flags & TRACE_ITER_ANNOTATE))
2044 if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
2047 if (cpumask_test_cpu(iter->cpu, iter->started))
2050 if (iter->tr->data[iter->cpu]->skipped_entries)
2053 cpumask_set_cpu(iter->cpu, iter->started);
2055 /* Don't print started cpu buffer for the first entry of the trace */
2057 trace_seq_printf(s, "##### CPU %u buffer started ####\n",
2061 static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
2063 struct trace_seq *s = &iter->seq;
2064 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
2065 struct trace_entry *entry;
2066 struct trace_event *event;
2070 test_cpu_buff_start(iter);
2072 event = ftrace_find_event(entry->type);
2074 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
2075 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
2076 if (!trace_print_lat_context(iter))
2079 if (!trace_print_context(iter))
2085 return event->funcs->trace(iter, sym_flags, event);
2087 if (!trace_seq_printf(s, "Unknown type %d\n", entry->type))
2090 return TRACE_TYPE_HANDLED;
2092 return TRACE_TYPE_PARTIAL_LINE;
2095 static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
2097 struct trace_seq *s = &iter->seq;
2098 struct trace_entry *entry;
2099 struct trace_event *event;
2103 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
2104 if (!trace_seq_printf(s, "%d %d %llu ",
2105 entry->pid, iter->cpu, iter->ts))
2109 event = ftrace_find_event(entry->type);
2111 return event->funcs->raw(iter, 0, event);
2113 if (!trace_seq_printf(s, "%d ?\n", entry->type))
2116 return TRACE_TYPE_HANDLED;
2118 return TRACE_TYPE_PARTIAL_LINE;
2121 static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
2123 struct trace_seq *s = &iter->seq;
2124 unsigned char newline = '\n';
2125 struct trace_entry *entry;
2126 struct trace_event *event;
2130 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
2131 SEQ_PUT_HEX_FIELD_RET(s, entry->pid);
2132 SEQ_PUT_HEX_FIELD_RET(s, iter->cpu);
2133 SEQ_PUT_HEX_FIELD_RET(s, iter->ts);
2136 event = ftrace_find_event(entry->type);
2138 enum print_line_t ret = event->funcs->hex(iter, 0, event);
2139 if (ret != TRACE_TYPE_HANDLED)
2143 SEQ_PUT_FIELD_RET(s, newline);
2145 return TRACE_TYPE_HANDLED;
2148 static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
2150 struct trace_seq *s = &iter->seq;
2151 struct trace_entry *entry;
2152 struct trace_event *event;
2156 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
2157 SEQ_PUT_FIELD_RET(s, entry->pid);
2158 SEQ_PUT_FIELD_RET(s, iter->cpu);
2159 SEQ_PUT_FIELD_RET(s, iter->ts);
2162 event = ftrace_find_event(entry->type);
2163 return event ? event->funcs->binary(iter, 0, event) :
2167 int trace_empty(struct trace_iterator *iter)
2171 /* If we are looking at one CPU buffer, only check that one */
2172 if (iter->cpu_file != TRACE_PIPE_ALL_CPU) {
2173 cpu = iter->cpu_file;
2174 if (iter->buffer_iter[cpu]) {
2175 if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
2178 if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu))
2184 for_each_tracing_cpu(cpu) {
2185 if (iter->buffer_iter[cpu]) {
2186 if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
2189 if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu))
2197 /* Called with trace_event_read_lock() held. */
2198 enum print_line_t print_trace_line(struct trace_iterator *iter)
2200 enum print_line_t ret;
2202 if (iter->lost_events &&
2203 !trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
2204 iter->cpu, iter->lost_events))
2205 return TRACE_TYPE_PARTIAL_LINE;
2207 if (iter->trace && iter->trace->print_line) {
2208 ret = iter->trace->print_line(iter);
2209 if (ret != TRACE_TYPE_UNHANDLED)
2213 if (iter->ent->type == TRACE_BPRINT &&
2214 trace_flags & TRACE_ITER_PRINTK &&
2215 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
2216 return trace_print_bprintk_msg_only(iter);
2218 if (iter->ent->type == TRACE_PRINT &&
2219 trace_flags & TRACE_ITER_PRINTK &&
2220 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
2221 return trace_print_printk_msg_only(iter);
2223 if (trace_flags & TRACE_ITER_BIN)
2224 return print_bin_fmt(iter);
2226 if (trace_flags & TRACE_ITER_HEX)
2227 return print_hex_fmt(iter);
2229 if (trace_flags & TRACE_ITER_RAW)
2230 return print_raw_fmt(iter);
2232 return print_trace_fmt(iter);
2235 void trace_latency_header(struct seq_file *m)
2237 struct trace_iterator *iter = m->private;
2239 /* print nothing if the buffers are empty */
2240 if (trace_empty(iter))
2243 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
2244 print_trace_header(m, iter);
2246 if (!(trace_flags & TRACE_ITER_VERBOSE))
2247 print_lat_help_header(m);
2250 void trace_default_header(struct seq_file *m)
2252 struct trace_iterator *iter = m->private;
2254 if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
2257 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
2258 /* print nothing if the buffers are empty */
2259 if (trace_empty(iter))
2261 print_trace_header(m, iter);
2262 if (!(trace_flags & TRACE_ITER_VERBOSE))
2263 print_lat_help_header(m);
2265 if (!(trace_flags & TRACE_ITER_VERBOSE)) {
2266 if (trace_flags & TRACE_ITER_IRQ_INFO)
2267 print_func_help_header_irq(iter->tr, m);
2269 print_func_help_header(iter->tr, m);
2274 static void test_ftrace_alive(struct seq_file *m)
2276 if (!ftrace_is_dead())
2278 seq_printf(m, "# WARNING: FUNCTION TRACING IS CORRUPTED\n");
2279 seq_printf(m, "# MAY BE MISSING FUNCTION EVENTS\n");
2282 static int s_show(struct seq_file *m, void *v)
2284 struct trace_iterator *iter = v;
2287 if (iter->ent == NULL) {
2289 seq_printf(m, "# tracer: %s\n", iter->trace->name);
2291 test_ftrace_alive(m);
2293 if (iter->trace && iter->trace->print_header)
2294 iter->trace->print_header(m);
2296 trace_default_header(m);
2298 } else if (iter->leftover) {
2300 * If we filled the seq_file buffer earlier, we
2301 * want to just show it now.
2303 ret = trace_print_seq(m, &iter->seq);
2305 /* ret should this time be zero, but you never know */
2306 iter->leftover = ret;
2309 print_trace_line(iter);
2310 ret = trace_print_seq(m, &iter->seq);
2312 * If we overflow the seq_file buffer, then it will
2313 * ask us for this data again at start up.
2315 * ret is 0 if seq_file write succeeded.
2318 iter->leftover = ret;
2324 static const struct seq_operations tracer_seq_ops = {
2331 static struct trace_iterator *
2332 __tracing_open(struct inode *inode, struct file *file)
2334 long cpu_file = (long) inode->i_private;
2335 void *fail_ret = ERR_PTR(-ENOMEM);
2336 struct trace_iterator *iter;
2340 if (tracing_disabled)
2341 return ERR_PTR(-ENODEV);
2343 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2345 return ERR_PTR(-ENOMEM);
2348 * We make a copy of the current tracer to avoid concurrent
2349 * changes on it while we are reading.
2351 mutex_lock(&trace_types_lock);
2352 iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL);
2357 *iter->trace = *current_trace;
2359 if (!zalloc_cpumask_var(&iter->started, GFP_KERNEL))
2362 if (current_trace && current_trace->print_max)
2365 iter->tr = &global_trace;
2367 mutex_init(&iter->mutex);
2368 iter->cpu_file = cpu_file;
2370 /* Notify the tracer early; before we stop tracing. */
2371 if (iter->trace && iter->trace->open)
2372 iter->trace->open(iter);
2374 /* Annotate start of buffers if we had overruns */
2375 if (ring_buffer_overruns(iter->tr->buffer))
2376 iter->iter_flags |= TRACE_FILE_ANNOTATE;
2378 /* stop the trace while dumping */
2381 if (iter->cpu_file == TRACE_PIPE_ALL_CPU) {
2382 for_each_tracing_cpu(cpu) {
2383 iter->buffer_iter[cpu] =
2384 ring_buffer_read_prepare(iter->tr->buffer, cpu);
2386 ring_buffer_read_prepare_sync();
2387 for_each_tracing_cpu(cpu) {
2388 ring_buffer_read_start(iter->buffer_iter[cpu]);
2389 tracing_iter_reset(iter, cpu);
2392 cpu = iter->cpu_file;
2393 iter->buffer_iter[cpu] =
2394 ring_buffer_read_prepare(iter->tr->buffer, cpu);
2395 ring_buffer_read_prepare_sync();
2396 ring_buffer_read_start(iter->buffer_iter[cpu]);
2397 tracing_iter_reset(iter, cpu);
2400 ret = seq_open(file, &tracer_seq_ops);
2402 fail_ret = ERR_PTR(ret);
2406 m = file->private_data;
2409 mutex_unlock(&trace_types_lock);
2414 for_each_tracing_cpu(cpu) {
2415 if (iter->buffer_iter[cpu])
2416 ring_buffer_read_finish(iter->buffer_iter[cpu]);
2418 free_cpumask_var(iter->started);
2421 mutex_unlock(&trace_types_lock);
2428 int tracing_open_generic(struct inode *inode, struct file *filp)
2430 if (tracing_disabled)
2433 filp->private_data = inode->i_private;
2437 static int tracing_release(struct inode *inode, struct file *file)
2439 struct seq_file *m = file->private_data;
2440 struct trace_iterator *iter;
2443 if (!(file->f_mode & FMODE_READ))
2448 mutex_lock(&trace_types_lock);
2449 for_each_tracing_cpu(cpu) {
2450 if (iter->buffer_iter[cpu])
2451 ring_buffer_read_finish(iter->buffer_iter[cpu]);
2454 if (iter->trace && iter->trace->close)
2455 iter->trace->close(iter);
2457 /* reenable tracing if it was previously enabled */
2459 mutex_unlock(&trace_types_lock);
2461 seq_release(inode, file);
2462 mutex_destroy(&iter->mutex);
2463 free_cpumask_var(iter->started);
2469 static int tracing_open(struct inode *inode, struct file *file)
2471 struct trace_iterator *iter;
2474 /* If this file was open for write, then erase contents */
2475 if ((file->f_mode & FMODE_WRITE) &&
2476 (file->f_flags & O_TRUNC)) {
2477 long cpu = (long) inode->i_private;
2479 if (cpu == TRACE_PIPE_ALL_CPU)
2480 tracing_reset_online_cpus(&global_trace);
2482 tracing_reset(&global_trace, cpu);
2485 if (file->f_mode & FMODE_READ) {
2486 iter = __tracing_open(inode, file);
2488 ret = PTR_ERR(iter);
2489 else if (trace_flags & TRACE_ITER_LATENCY_FMT)
2490 iter->iter_flags |= TRACE_FILE_LAT_FMT;
2496 t_next(struct seq_file *m, void *v, loff_t *pos)
2498 struct tracer *t = v;
2508 static void *t_start(struct seq_file *m, loff_t *pos)
2513 mutex_lock(&trace_types_lock);
2514 for (t = trace_types; t && l < *pos; t = t_next(m, t, &l))
2520 static void t_stop(struct seq_file *m, void *p)
2522 mutex_unlock(&trace_types_lock);
2525 static int t_show(struct seq_file *m, void *v)
2527 struct tracer *t = v;
2532 seq_printf(m, "%s", t->name);
2541 static const struct seq_operations show_traces_seq_ops = {
2548 static int show_traces_open(struct inode *inode, struct file *file)
2550 if (tracing_disabled)
2553 return seq_open(file, &show_traces_seq_ops);
2557 tracing_write_stub(struct file *filp, const char __user *ubuf,
2558 size_t count, loff_t *ppos)
2563 static loff_t tracing_seek(struct file *file, loff_t offset, int origin)
2565 if (file->f_mode & FMODE_READ)
2566 return seq_lseek(file, offset, origin);
2571 static const struct file_operations tracing_fops = {
2572 .open = tracing_open,
2574 .write = tracing_write_stub,
2575 .llseek = tracing_seek,
2576 .release = tracing_release,
2579 static const struct file_operations show_traces_fops = {
2580 .open = show_traces_open,
2582 .release = seq_release,
2583 .llseek = seq_lseek,
2587 * Only trace on a CPU if the bitmask is set:
2589 static cpumask_var_t tracing_cpumask;
2592 * The tracer itself will not take this lock, but still we want
2593 * to provide a consistent cpumask to user-space:
2595 static DEFINE_MUTEX(tracing_cpumask_update_lock);
2598 * Temporary storage for the character representation of the
2599 * CPU bitmask (and one more byte for the newline):
2601 static char mask_str[NR_CPUS + 1];
2604 tracing_cpumask_read(struct file *filp, char __user *ubuf,
2605 size_t count, loff_t *ppos)
2609 mutex_lock(&tracing_cpumask_update_lock);
2611 len = cpumask_scnprintf(mask_str, count, tracing_cpumask);
2612 if (count - len < 2) {
2616 len += sprintf(mask_str + len, "\n");
2617 count = simple_read_from_buffer(ubuf, count, ppos, mask_str, NR_CPUS+1);
2620 mutex_unlock(&tracing_cpumask_update_lock);
2626 tracing_cpumask_write(struct file *filp, const char __user *ubuf,
2627 size_t count, loff_t *ppos)
2630 cpumask_var_t tracing_cpumask_new;
2632 if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
2635 err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
2639 mutex_lock(&tracing_cpumask_update_lock);
2641 local_irq_disable();
2642 arch_spin_lock(&ftrace_max_lock);
2643 for_each_tracing_cpu(cpu) {
2645 * Increase/decrease the disabled counter if we are
2646 * about to flip a bit in the cpumask:
2648 if (cpumask_test_cpu(cpu, tracing_cpumask) &&
2649 !cpumask_test_cpu(cpu, tracing_cpumask_new)) {
2650 atomic_inc(&global_trace.data[cpu]->disabled);
2652 if (!cpumask_test_cpu(cpu, tracing_cpumask) &&
2653 cpumask_test_cpu(cpu, tracing_cpumask_new)) {
2654 atomic_dec(&global_trace.data[cpu]->disabled);
2657 arch_spin_unlock(&ftrace_max_lock);
2660 cpumask_copy(tracing_cpumask, tracing_cpumask_new);
2662 mutex_unlock(&tracing_cpumask_update_lock);
2663 free_cpumask_var(tracing_cpumask_new);
2668 free_cpumask_var(tracing_cpumask_new);
2673 static const struct file_operations tracing_cpumask_fops = {
2674 .open = tracing_open_generic,
2675 .read = tracing_cpumask_read,
2676 .write = tracing_cpumask_write,
2677 .llseek = generic_file_llseek,
2680 static int tracing_trace_options_show(struct seq_file *m, void *v)
2682 struct tracer_opt *trace_opts;
2686 mutex_lock(&trace_types_lock);
2687 tracer_flags = current_trace->flags->val;
2688 trace_opts = current_trace->flags->opts;
2690 for (i = 0; trace_options[i]; i++) {
2691 if (trace_flags & (1 << i))
2692 seq_printf(m, "%s\n", trace_options[i]);
2694 seq_printf(m, "no%s\n", trace_options[i]);
2697 for (i = 0; trace_opts[i].name; i++) {
2698 if (tracer_flags & trace_opts[i].bit)
2699 seq_printf(m, "%s\n", trace_opts[i].name);
2701 seq_printf(m, "no%s\n", trace_opts[i].name);
2703 mutex_unlock(&trace_types_lock);
2708 static int __set_tracer_option(struct tracer *trace,
2709 struct tracer_flags *tracer_flags,
2710 struct tracer_opt *opts, int neg)
2714 ret = trace->set_flag(tracer_flags->val, opts->bit, !neg);
2719 tracer_flags->val &= ~opts->bit;
2721 tracer_flags->val |= opts->bit;
2725 /* Try to assign a tracer specific option */
2726 static int set_tracer_option(struct tracer *trace, char *cmp, int neg)
2728 struct tracer_flags *tracer_flags = trace->flags;
2729 struct tracer_opt *opts = NULL;
2732 for (i = 0; tracer_flags->opts[i].name; i++) {
2733 opts = &tracer_flags->opts[i];
2735 if (strcmp(cmp, opts->name) == 0)
2736 return __set_tracer_option(trace, trace->flags,
2743 static void set_tracer_flags(unsigned int mask, int enabled)
2745 /* do nothing if flag is already set */
2746 if (!!(trace_flags & mask) == !!enabled)
2750 trace_flags |= mask;
2752 trace_flags &= ~mask;
2754 if (mask == TRACE_ITER_RECORD_CMD)
2755 trace_event_enable_cmd_record(enabled);
2757 if (mask == TRACE_ITER_OVERWRITE)
2758 ring_buffer_change_overwrite(global_trace.buffer, enabled);
2762 tracing_trace_options_write(struct file *filp, const char __user *ubuf,
2763 size_t cnt, loff_t *ppos)
2771 if (cnt >= sizeof(buf))
2774 if (copy_from_user(&buf, ubuf, cnt))
2778 cmp = strstrip(buf);
2780 if (strncmp(cmp, "no", 2) == 0) {
2785 for (i = 0; trace_options[i]; i++) {
2786 if (strcmp(cmp, trace_options[i]) == 0) {
2787 set_tracer_flags(1 << i, !neg);
2792 /* If no option could be set, test the specific tracer options */
2793 if (!trace_options[i]) {
2794 mutex_lock(&trace_types_lock);
2795 ret = set_tracer_option(current_trace, cmp, neg);
2796 mutex_unlock(&trace_types_lock);
2806 static int tracing_trace_options_open(struct inode *inode, struct file *file)
2808 if (tracing_disabled)
2810 return single_open(file, tracing_trace_options_show, NULL);
2813 static const struct file_operations tracing_iter_fops = {
2814 .open = tracing_trace_options_open,
2816 .llseek = seq_lseek,
2817 .release = single_release,
2818 .write = tracing_trace_options_write,
2821 static const char readme_msg[] =
2822 "tracing mini-HOWTO:\n\n"
2823 "# mount -t debugfs nodev /sys/kernel/debug\n\n"
2824 "# cat /sys/kernel/debug/tracing/available_tracers\n"
2825 "wakeup wakeup_rt preemptirqsoff preemptoff irqsoff function nop\n\n"
2826 "# cat /sys/kernel/debug/tracing/current_tracer\n"
2828 "# echo wakeup > /sys/kernel/debug/tracing/current_tracer\n"
2829 "# cat /sys/kernel/debug/tracing/current_tracer\n"
2831 "# cat /sys/kernel/debug/tracing/trace_options\n"
2832 "noprint-parent nosym-offset nosym-addr noverbose\n"
2833 "# echo print-parent > /sys/kernel/debug/tracing/trace_options\n"
2834 "# echo 1 > /sys/kernel/debug/tracing/tracing_on\n"
2835 "# cat /sys/kernel/debug/tracing/trace > /tmp/trace.txt\n"
2836 "# echo 0 > /sys/kernel/debug/tracing/tracing_on\n"
2840 tracing_readme_read(struct file *filp, char __user *ubuf,
2841 size_t cnt, loff_t *ppos)
2843 return simple_read_from_buffer(ubuf, cnt, ppos,
2844 readme_msg, strlen(readme_msg));
2847 static const struct file_operations tracing_readme_fops = {
2848 .open = tracing_open_generic,
2849 .read = tracing_readme_read,
2850 .llseek = generic_file_llseek,
2854 tracing_saved_cmdlines_read(struct file *file, char __user *ubuf,
2855 size_t cnt, loff_t *ppos)
2864 file_buf = kmalloc(SAVED_CMDLINES*(16+TASK_COMM_LEN), GFP_KERNEL);
2868 buf_comm = kmalloc(TASK_COMM_LEN, GFP_KERNEL);
2876 for (i = 0; i < SAVED_CMDLINES; i++) {
2879 pid = map_cmdline_to_pid[i];
2880 if (pid == -1 || pid == NO_CMDLINE_MAP)
2883 trace_find_cmdline(pid, buf_comm);
2884 r = sprintf(buf, "%d %s\n", pid, buf_comm);
2889 len = simple_read_from_buffer(ubuf, cnt, ppos,
2898 static const struct file_operations tracing_saved_cmdlines_fops = {
2899 .open = tracing_open_generic,
2900 .read = tracing_saved_cmdlines_read,
2901 .llseek = generic_file_llseek,
2905 tracing_ctrl_read(struct file *filp, char __user *ubuf,
2906 size_t cnt, loff_t *ppos)
2911 r = sprintf(buf, "%u\n", tracer_enabled);
2912 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2916 tracing_ctrl_write(struct file *filp, const char __user *ubuf,
2917 size_t cnt, loff_t *ppos)
2919 struct trace_array *tr = filp->private_data;
2923 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
2929 mutex_lock(&trace_types_lock);
2930 if (tracer_enabled ^ val) {
2932 /* Only need to warn if this is used to change the state */
2933 WARN_ONCE(1, "tracing_enabled is deprecated. Use tracing_on");
2937 if (current_trace->start)
2938 current_trace->start(tr);
2943 if (current_trace->stop)
2944 current_trace->stop(tr);
2947 mutex_unlock(&trace_types_lock);
2955 tracing_set_trace_read(struct file *filp, char __user *ubuf,
2956 size_t cnt, loff_t *ppos)
2958 char buf[MAX_TRACER_SIZE+2];
2961 mutex_lock(&trace_types_lock);
2963 r = sprintf(buf, "%s\n", current_trace->name);
2965 r = sprintf(buf, "\n");
2966 mutex_unlock(&trace_types_lock);
2968 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2971 int tracer_init(struct tracer *t, struct trace_array *tr)
2973 tracing_reset_online_cpus(tr);
2977 static int __tracing_resize_ring_buffer(unsigned long size)
2982 * If kernel or user changes the size of the ring buffer
2983 * we use the size that was given, and we can forget about
2984 * expanding it later.
2986 ring_buffer_expanded = 1;
2988 ret = ring_buffer_resize(global_trace.buffer, size);
2992 if (!current_trace->use_max_tr)
2995 ret = ring_buffer_resize(max_tr.buffer, size);
2999 r = ring_buffer_resize(global_trace.buffer,
3000 global_trace.entries);
3003 * AARGH! We are left with different
3004 * size max buffer!!!!
3005 * The max buffer is our "snapshot" buffer.
3006 * When a tracer needs a snapshot (one of the
3007 * latency tracers), it swaps the max buffer
3008 * with the saved snap shot. We succeeded to
3009 * update the size of the main buffer, but failed to
3010 * update the size of the max buffer. But when we tried
3011 * to reset the main buffer to the original size, we
3012 * failed there too. This is very unlikely to
3013 * happen, but if it does, warn and kill all
3017 tracing_disabled = 1;
3022 max_tr.entries = size;
3024 global_trace.entries = size;
3029 static ssize_t tracing_resize_ring_buffer(unsigned long size)
3031 int cpu, ret = size;
3033 mutex_lock(&trace_types_lock);
3037 /* disable all cpu buffers */
3038 for_each_tracing_cpu(cpu) {
3039 if (global_trace.data[cpu])
3040 atomic_inc(&global_trace.data[cpu]->disabled);
3041 if (max_tr.data[cpu])
3042 atomic_inc(&max_tr.data[cpu]->disabled);
3045 if (size != global_trace.entries)
3046 ret = __tracing_resize_ring_buffer(size);
3051 for_each_tracing_cpu(cpu) {
3052 if (global_trace.data[cpu])
3053 atomic_dec(&global_trace.data[cpu]->disabled);
3054 if (max_tr.data[cpu])
3055 atomic_dec(&max_tr.data[cpu]->disabled);
3059 mutex_unlock(&trace_types_lock);
3066 * tracing_update_buffers - used by tracing facility to expand ring buffers
3068 * To save on memory when the tracing is never used on a system with it
3069 * configured in. The ring buffers are set to a minimum size. But once
3070 * a user starts to use the tracing facility, then they need to grow
3071 * to their default size.
3073 * This function is to be called when a tracer is about to be used.
3075 int tracing_update_buffers(void)
3079 mutex_lock(&trace_types_lock);
3080 if (!ring_buffer_expanded)
3081 ret = __tracing_resize_ring_buffer(trace_buf_size);
3082 mutex_unlock(&trace_types_lock);
3087 struct trace_option_dentry;
3089 static struct trace_option_dentry *
3090 create_trace_option_files(struct tracer *tracer);
3093 destroy_trace_option_files(struct trace_option_dentry *topts);
3095 static int tracing_set_tracer(const char *buf)
3097 static struct trace_option_dentry *topts;
3098 struct trace_array *tr = &global_trace;
3102 mutex_lock(&trace_types_lock);
3104 if (!ring_buffer_expanded) {
3105 ret = __tracing_resize_ring_buffer(trace_buf_size);
3111 for (t = trace_types; t; t = t->next) {
3112 if (strcmp(t->name, buf) == 0)
3119 if (t == current_trace)
3122 trace_branch_disable();
3123 if (current_trace && current_trace->reset)
3124 current_trace->reset(tr);
3125 if (current_trace && current_trace->use_max_tr) {
3127 * We don't free the ring buffer. instead, resize it because
3128 * The max_tr ring buffer has some state (e.g. ring->clock) and
3129 * we want preserve it.
3131 ring_buffer_resize(max_tr.buffer, 1);
3134 destroy_trace_option_files(topts);
3138 topts = create_trace_option_files(current_trace);
3139 if (current_trace->use_max_tr) {
3140 ret = ring_buffer_resize(max_tr.buffer, global_trace.entries);
3143 max_tr.entries = global_trace.entries;
3147 ret = tracer_init(t, tr);
3152 trace_branch_enable(tr);
3154 mutex_unlock(&trace_types_lock);
3160 tracing_set_trace_write(struct file *filp, const char __user *ubuf,
3161 size_t cnt, loff_t *ppos)
3163 char buf[MAX_TRACER_SIZE+1];
3170 if (cnt > MAX_TRACER_SIZE)
3171 cnt = MAX_TRACER_SIZE;
3173 if (copy_from_user(&buf, ubuf, cnt))
3178 /* strip ending whitespace. */
3179 for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
3182 err = tracing_set_tracer(buf);
3192 tracing_max_lat_read(struct file *filp, char __user *ubuf,
3193 size_t cnt, loff_t *ppos)
3195 unsigned long *ptr = filp->private_data;
3199 r = snprintf(buf, sizeof(buf), "%ld\n",
3200 *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
3201 if (r > sizeof(buf))
3203 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
3207 tracing_max_lat_write(struct file *filp, const char __user *ubuf,
3208 size_t cnt, loff_t *ppos)
3210 unsigned long *ptr = filp->private_data;
3214 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
3223 static int tracing_open_pipe(struct inode *inode, struct file *filp)
3225 long cpu_file = (long) inode->i_private;
3226 struct trace_iterator *iter;
3229 if (tracing_disabled)
3232 mutex_lock(&trace_types_lock);
3234 /* create a buffer to store the information to pass to userspace */
3235 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3242 * We make a copy of the current tracer to avoid concurrent
3243 * changes on it while we are reading.
3245 iter->trace = kmalloc(sizeof(*iter->trace), GFP_KERNEL);
3251 *iter->trace = *current_trace;
3253 if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
3258 /* trace pipe does not show start of buffer */
3259 cpumask_setall(iter->started);
3261 if (trace_flags & TRACE_ITER_LATENCY_FMT)
3262 iter->iter_flags |= TRACE_FILE_LAT_FMT;
3264 iter->cpu_file = cpu_file;
3265 iter->tr = &global_trace;
3266 mutex_init(&iter->mutex);
3267 filp->private_data = iter;
3269 if (iter->trace->pipe_open)
3270 iter->trace->pipe_open(iter);
3272 nonseekable_open(inode, filp);
3274 mutex_unlock(&trace_types_lock);
3280 mutex_unlock(&trace_types_lock);
3284 static int tracing_release_pipe(struct inode *inode, struct file *file)
3286 struct trace_iterator *iter = file->private_data;
3288 mutex_lock(&trace_types_lock);
3290 if (iter->trace->pipe_close)
3291 iter->trace->pipe_close(iter);
3293 mutex_unlock(&trace_types_lock);
3295 free_cpumask_var(iter->started);
3296 mutex_destroy(&iter->mutex);
3304 tracing_poll_pipe(struct file *filp, poll_table *poll_table)
3306 struct trace_iterator *iter = filp->private_data;
3308 if (trace_flags & TRACE_ITER_BLOCK) {
3310 * Always select as readable when in blocking mode
3312 return POLLIN | POLLRDNORM;
3314 if (!trace_empty(iter))
3315 return POLLIN | POLLRDNORM;
3316 poll_wait(filp, &trace_wait, poll_table);
3317 if (!trace_empty(iter))
3318 return POLLIN | POLLRDNORM;
3325 void default_wait_pipe(struct trace_iterator *iter)
3329 prepare_to_wait(&trace_wait, &wait, TASK_INTERRUPTIBLE);
3331 if (trace_empty(iter))
3334 finish_wait(&trace_wait, &wait);
3338 * This is a make-shift waitqueue.
3339 * A tracer might use this callback on some rare cases:
3341 * 1) the current tracer might hold the runqueue lock when it wakes up
3342 * a reader, hence a deadlock (sched, function, and function graph tracers)
3343 * 2) the function tracers, trace all functions, we don't want
3344 * the overhead of calling wake_up and friends
3345 * (and tracing them too)
3347 * Anyway, this is really very primitive wakeup.
3349 void poll_wait_pipe(struct trace_iterator *iter)
3351 set_current_state(TASK_INTERRUPTIBLE);
3352 /* sleep for 100 msecs, and try again. */
3353 schedule_timeout(HZ / 10);
3356 /* Must be called with trace_types_lock mutex held. */
3357 static int tracing_wait_pipe(struct file *filp)
3359 struct trace_iterator *iter = filp->private_data;
3361 while (trace_empty(iter)) {
3363 if ((filp->f_flags & O_NONBLOCK)) {
3367 mutex_unlock(&iter->mutex);
3369 iter->trace->wait_pipe(iter);
3371 mutex_lock(&iter->mutex);
3373 if (signal_pending(current))
3377 * We block until we read something and tracing is disabled.
3378 * We still block if tracing is disabled, but we have never
3379 * read anything. This allows a user to cat this file, and
3380 * then enable tracing. But after we have read something,
3381 * we give an EOF when tracing is again disabled.
3383 * iter->pos will be 0 if we haven't read anything.
3385 if (!tracer_enabled && iter->pos)
3396 tracing_read_pipe(struct file *filp, char __user *ubuf,
3397 size_t cnt, loff_t *ppos)
3399 struct trace_iterator *iter = filp->private_data;
3400 static struct tracer *old_tracer;
3403 /* return any leftover data */
3404 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
3408 trace_seq_init(&iter->seq);
3410 /* copy the tracer to avoid using a global lock all around */
3411 mutex_lock(&trace_types_lock);
3412 if (unlikely(old_tracer != current_trace && current_trace)) {
3413 old_tracer = current_trace;
3414 *iter->trace = *current_trace;
3416 mutex_unlock(&trace_types_lock);
3419 * Avoid more than one consumer on a single file descriptor
3420 * This is just a matter of traces coherency, the ring buffer itself
3423 mutex_lock(&iter->mutex);
3424 if (iter->trace->read) {
3425 sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
3431 sret = tracing_wait_pipe(filp);
3435 /* stop when tracing is finished */
3436 if (trace_empty(iter)) {
3441 if (cnt >= PAGE_SIZE)
3442 cnt = PAGE_SIZE - 1;
3444 /* reset all but tr, trace, and overruns */
3445 memset(&iter->seq, 0,
3446 sizeof(struct trace_iterator) -
3447 offsetof(struct trace_iterator, seq));
3450 trace_event_read_lock();
3451 trace_access_lock(iter->cpu_file);
3452 while (trace_find_next_entry_inc(iter) != NULL) {
3453 enum print_line_t ret;
3454 int len = iter->seq.len;
3456 ret = print_trace_line(iter);
3457 if (ret == TRACE_TYPE_PARTIAL_LINE) {
3458 /* don't print partial lines */
3459 iter->seq.len = len;
3462 if (ret != TRACE_TYPE_NO_CONSUME)
3463 trace_consume(iter);
3465 if (iter->seq.len >= cnt)
3469 * Setting the full flag means we reached the trace_seq buffer
3470 * size and we should leave by partial output condition above.
3471 * One of the trace_seq_* functions is not used properly.
3473 WARN_ONCE(iter->seq.full, "full flag set for trace type %d",
3476 trace_access_unlock(iter->cpu_file);
3477 trace_event_read_unlock();
3479 /* Now copy what we have to the user */
3480 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
3481 if (iter->seq.readpos >= iter->seq.len)
3482 trace_seq_init(&iter->seq);
3485 * If there was nothing to send to user, in spite of consuming trace
3486 * entries, go back to wait for more entries.
3492 mutex_unlock(&iter->mutex);
3497 static void tracing_pipe_buf_release(struct pipe_inode_info *pipe,
3498 struct pipe_buffer *buf)
3500 __free_page(buf->page);
3503 static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
3506 __free_page(spd->pages[idx]);
3509 static const struct pipe_buf_operations tracing_pipe_buf_ops = {
3511 .map = generic_pipe_buf_map,
3512 .unmap = generic_pipe_buf_unmap,
3513 .confirm = generic_pipe_buf_confirm,
3514 .release = tracing_pipe_buf_release,
3515 .steal = generic_pipe_buf_steal,
3516 .get = generic_pipe_buf_get,
3520 tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
3525 /* Seq buffer is page-sized, exactly what we need. */
3527 count = iter->seq.len;
3528 ret = print_trace_line(iter);
3529 count = iter->seq.len - count;
3532 iter->seq.len -= count;
3535 if (ret == TRACE_TYPE_PARTIAL_LINE) {
3536 iter->seq.len -= count;
3540 if (ret != TRACE_TYPE_NO_CONSUME)
3541 trace_consume(iter);
3543 if (!trace_find_next_entry_inc(iter)) {
3553 static ssize_t tracing_splice_read_pipe(struct file *filp,
3555 struct pipe_inode_info *pipe,
3559 struct page *pages_def[PIPE_DEF_BUFFERS];
3560 struct partial_page partial_def[PIPE_DEF_BUFFERS];
3561 struct trace_iterator *iter = filp->private_data;
3562 struct splice_pipe_desc spd = {
3564 .partial = partial_def,
3565 .nr_pages = 0, /* This gets updated below. */
3567 .ops = &tracing_pipe_buf_ops,
3568 .spd_release = tracing_spd_release_pipe,
3570 static struct tracer *old_tracer;
3575 if (splice_grow_spd(pipe, &spd))
3578 /* copy the tracer to avoid using a global lock all around */
3579 mutex_lock(&trace_types_lock);
3580 if (unlikely(old_tracer != current_trace && current_trace)) {
3581 old_tracer = current_trace;
3582 *iter->trace = *current_trace;
3584 mutex_unlock(&trace_types_lock);
3586 mutex_lock(&iter->mutex);
3588 if (iter->trace->splice_read) {
3589 ret = iter->trace->splice_read(iter, filp,
3590 ppos, pipe, len, flags);
3595 ret = tracing_wait_pipe(filp);
3599 if (!iter->ent && !trace_find_next_entry_inc(iter)) {
3604 trace_event_read_lock();
3605 trace_access_lock(iter->cpu_file);
3607 /* Fill as many pages as possible. */
3608 for (i = 0, rem = len; i < pipe->buffers && rem; i++) {
3609 spd.pages[i] = alloc_page(GFP_KERNEL);
3613 rem = tracing_fill_pipe_page(rem, iter);
3615 /* Copy the data into the page, so we can start over. */
3616 ret = trace_seq_to_buffer(&iter->seq,
3617 page_address(spd.pages[i]),
3620 __free_page(spd.pages[i]);
3623 spd.partial[i].offset = 0;
3624 spd.partial[i].len = iter->seq.len;
3626 trace_seq_init(&iter->seq);
3629 trace_access_unlock(iter->cpu_file);
3630 trace_event_read_unlock();
3631 mutex_unlock(&iter->mutex);
3635 ret = splice_to_pipe(pipe, &spd);
3637 splice_shrink_spd(pipe, &spd);
3641 mutex_unlock(&iter->mutex);
3646 tracing_entries_read(struct file *filp, char __user *ubuf,
3647 size_t cnt, loff_t *ppos)
3649 struct trace_array *tr = filp->private_data;
3653 mutex_lock(&trace_types_lock);
3654 if (!ring_buffer_expanded)
3655 r = sprintf(buf, "%lu (expanded: %lu)\n",
3657 trace_buf_size >> 10);
3659 r = sprintf(buf, "%lu\n", tr->entries >> 10);
3660 mutex_unlock(&trace_types_lock);
3662 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
3666 tracing_entries_write(struct file *filp, const char __user *ubuf,
3667 size_t cnt, loff_t *ppos)
3672 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
3676 /* must have at least 1 entry */
3680 /* value is in KB */
3683 ret = tracing_resize_ring_buffer(val);
3693 tracing_total_entries_read(struct file *filp, char __user *ubuf,
3694 size_t cnt, loff_t *ppos)
3696 struct trace_array *tr = filp->private_data;
3699 unsigned long size = 0, expanded_size = 0;
3701 mutex_lock(&trace_types_lock);
3702 for_each_tracing_cpu(cpu) {
3703 size += tr->entries >> 10;
3704 if (!ring_buffer_expanded)
3705 expanded_size += trace_buf_size >> 10;
3707 if (ring_buffer_expanded)
3708 r = sprintf(buf, "%lu\n", size);
3710 r = sprintf(buf, "%lu (expanded: %lu)\n", size, expanded_size);
3711 mutex_unlock(&trace_types_lock);
3713 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
3717 tracing_free_buffer_write(struct file *filp, const char __user *ubuf,
3718 size_t cnt, loff_t *ppos)
3721 * There is no need to read what the user has written, this function
3722 * is just to make sure that there is no error when "echo" is used
3731 tracing_free_buffer_release(struct inode *inode, struct file *filp)
3733 /* disable tracing ? */
3734 if (trace_flags & TRACE_ITER_STOP_ON_FREE)
3736 /* resize the ring buffer to 0 */
3737 tracing_resize_ring_buffer(0);
3743 tracing_mark_write(struct file *filp, const char __user *ubuf,
3744 size_t cnt, loff_t *fpos)
3746 unsigned long addr = (unsigned long)ubuf;
3747 struct ring_buffer_event *event;
3748 struct ring_buffer *buffer;
3749 struct print_entry *entry;
3750 unsigned long irq_flags;
3751 struct page *pages[2];
3761 if (tracing_disabled)
3764 if (cnt > TRACE_BUF_SIZE)
3765 cnt = TRACE_BUF_SIZE;
3768 * Userspace is injecting traces into the kernel trace buffer.
3769 * We want to be as non intrusive as possible.
3770 * To do so, we do not want to allocate any special buffers
3771 * or take any locks, but instead write the userspace data
3772 * straight into the ring buffer.
3774 * First we need to pin the userspace buffer into memory,
3775 * which, most likely it is, because it just referenced it.
3776 * But there's no guarantee that it is. By using get_user_pages_fast()
3777 * and kmap_atomic/kunmap_atomic() we can get access to the
3778 * pages directly. We then write the data directly into the
3781 BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
3783 /* check if we cross pages */
3784 if ((addr & PAGE_MASK) != ((addr + cnt) & PAGE_MASK))
3787 offset = addr & (PAGE_SIZE - 1);
3790 ret = get_user_pages_fast(addr, nr_pages, 0, pages);
3791 if (ret < nr_pages) {
3793 put_page(pages[ret]);
3798 page1 = kmap_atomic(pages[0]);
3800 page2 = kmap_atomic(pages[1]);
3802 local_save_flags(irq_flags);
3803 size = sizeof(*entry) + cnt + 2; /* possible \n added */
3804 buffer = global_trace.buffer;
3805 event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
3806 irq_flags, preempt_count());
3808 /* Ring buffer disabled, return as if not open for write */
3813 entry = ring_buffer_event_data(event);
3814 entry->ip = _THIS_IP_;
3816 if (nr_pages == 2) {
3817 len = PAGE_SIZE - offset;
3818 memcpy(&entry->buf, page1 + offset, len);
3819 memcpy(&entry->buf[len], page2, cnt - len);
3821 memcpy(&entry->buf, page1 + offset, cnt);
3823 if (entry->buf[cnt - 1] != '\n') {
3824 entry->buf[cnt] = '\n';
3825 entry->buf[cnt + 1] = '\0';
3827 entry->buf[cnt] = '\0';
3829 ring_buffer_unlock_commit(buffer, event);
3837 kunmap_atomic(page2);
3838 kunmap_atomic(page1);
3839 while (nr_pages > 0)
3840 put_page(pages[--nr_pages]);
3845 static int tracing_clock_show(struct seq_file *m, void *v)
3849 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++)
3851 "%s%s%s%s", i ? " " : "",
3852 i == trace_clock_id ? "[" : "", trace_clocks[i].name,
3853 i == trace_clock_id ? "]" : "");
3859 static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf,
3860 size_t cnt, loff_t *fpos)
3863 const char *clockstr;
3866 if (cnt >= sizeof(buf))
3869 if (copy_from_user(&buf, ubuf, cnt))
3874 clockstr = strstrip(buf);
3876 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) {
3877 if (strcmp(trace_clocks[i].name, clockstr) == 0)
3880 if (i == ARRAY_SIZE(trace_clocks))
3885 mutex_lock(&trace_types_lock);
3887 ring_buffer_set_clock(global_trace.buffer, trace_clocks[i].func);
3889 ring_buffer_set_clock(max_tr.buffer, trace_clocks[i].func);
3891 mutex_unlock(&trace_types_lock);
3898 static int tracing_clock_open(struct inode *inode, struct file *file)
3900 if (tracing_disabled)
3902 return single_open(file, tracing_clock_show, NULL);
3905 static const struct file_operations tracing_max_lat_fops = {
3906 .open = tracing_open_generic,
3907 .read = tracing_max_lat_read,
3908 .write = tracing_max_lat_write,
3909 .llseek = generic_file_llseek,
3912 static const struct file_operations tracing_ctrl_fops = {
3913 .open = tracing_open_generic,
3914 .read = tracing_ctrl_read,
3915 .write = tracing_ctrl_write,
3916 .llseek = generic_file_llseek,
3919 static const struct file_operations set_tracer_fops = {
3920 .open = tracing_open_generic,
3921 .read = tracing_set_trace_read,
3922 .write = tracing_set_trace_write,
3923 .llseek = generic_file_llseek,
3926 static const struct file_operations tracing_pipe_fops = {
3927 .open = tracing_open_pipe,
3928 .poll = tracing_poll_pipe,
3929 .read = tracing_read_pipe,
3930 .splice_read = tracing_splice_read_pipe,
3931 .release = tracing_release_pipe,
3932 .llseek = no_llseek,
3935 static const struct file_operations tracing_entries_fops = {
3936 .open = tracing_open_generic,
3937 .read = tracing_entries_read,
3938 .write = tracing_entries_write,
3939 .llseek = generic_file_llseek,
3942 static const struct file_operations tracing_total_entries_fops = {
3943 .open = tracing_open_generic,
3944 .read = tracing_total_entries_read,
3945 .llseek = generic_file_llseek,
3948 static const struct file_operations tracing_free_buffer_fops = {
3949 .write = tracing_free_buffer_write,
3950 .release = tracing_free_buffer_release,
3953 static const struct file_operations tracing_mark_fops = {
3954 .open = tracing_open_generic,
3955 .write = tracing_mark_write,
3956 .llseek = generic_file_llseek,
3959 static const struct file_operations trace_clock_fops = {
3960 .open = tracing_clock_open,
3962 .llseek = seq_lseek,
3963 .release = single_release,
3964 .write = tracing_clock_write,
3967 struct ftrace_buffer_info {
3968 struct trace_array *tr;
3974 static int tracing_buffers_open(struct inode *inode, struct file *filp)
3976 int cpu = (int)(long)inode->i_private;
3977 struct ftrace_buffer_info *info;
3979 if (tracing_disabled)
3982 info = kzalloc(sizeof(*info), GFP_KERNEL);
3986 info->tr = &global_trace;
3989 /* Force reading ring buffer for first read */
3990 info->read = (unsigned int)-1;
3992 filp->private_data = info;
3994 return nonseekable_open(inode, filp);
3998 tracing_buffers_read(struct file *filp, char __user *ubuf,
3999 size_t count, loff_t *ppos)
4001 struct ftrace_buffer_info *info = filp->private_data;
4009 info->spare = ring_buffer_alloc_read_page(info->tr->buffer, info->cpu);
4013 /* Do we have previous read data to read? */
4014 if (info->read < PAGE_SIZE)
4017 trace_access_lock(info->cpu);
4018 ret = ring_buffer_read_page(info->tr->buffer,
4022 trace_access_unlock(info->cpu);
4029 size = PAGE_SIZE - info->read;
4033 ret = copy_to_user(ubuf, info->spare + info->read, size);
4044 static int tracing_buffers_release(struct inode *inode, struct file *file)
4046 struct ftrace_buffer_info *info = file->private_data;
4049 ring_buffer_free_read_page(info->tr->buffer, info->spare);
4056 struct ring_buffer *buffer;
4061 static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
4062 struct pipe_buffer *buf)
4064 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
4069 ring_buffer_free_read_page(ref->buffer, ref->page);
4074 static int buffer_pipe_buf_steal(struct pipe_inode_info *pipe,
4075 struct pipe_buffer *buf)
4080 static void buffer_pipe_buf_get(struct pipe_inode_info *pipe,
4081 struct pipe_buffer *buf)
4083 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
4088 /* Pipe buffer operations for a buffer. */
4089 static const struct pipe_buf_operations buffer_pipe_buf_ops = {
4091 .map = generic_pipe_buf_map,
4092 .unmap = generic_pipe_buf_unmap,
4093 .confirm = generic_pipe_buf_confirm,
4094 .release = buffer_pipe_buf_release,
4095 .steal = buffer_pipe_buf_steal,
4096 .get = buffer_pipe_buf_get,
4100 * Callback from splice_to_pipe(), if we need to release some pages
4101 * at the end of the spd in case we error'ed out in filling the pipe.
4103 static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
4105 struct buffer_ref *ref =
4106 (struct buffer_ref *)spd->partial[i].private;
4111 ring_buffer_free_read_page(ref->buffer, ref->page);
4113 spd->partial[i].private = 0;
4117 tracing_buffers_splice_read(struct file *file, loff_t *ppos,
4118 struct pipe_inode_info *pipe, size_t len,
4121 struct ftrace_buffer_info *info = file->private_data;
4122 struct partial_page partial_def[PIPE_DEF_BUFFERS];
4123 struct page *pages_def[PIPE_DEF_BUFFERS];
4124 struct splice_pipe_desc spd = {
4126 .partial = partial_def,
4128 .ops = &buffer_pipe_buf_ops,
4129 .spd_release = buffer_spd_release,
4131 struct buffer_ref *ref;
4132 int entries, size, i;
4135 if (splice_grow_spd(pipe, &spd))
4138 if (*ppos & (PAGE_SIZE - 1)) {
4139 WARN_ONCE(1, "Ftrace: previous read must page-align\n");
4144 if (len & (PAGE_SIZE - 1)) {
4145 WARN_ONCE(1, "Ftrace: splice_read should page-align\n");
4146 if (len < PAGE_SIZE) {
4153 trace_access_lock(info->cpu);
4154 entries = ring_buffer_entries_cpu(info->tr->buffer, info->cpu);
4156 for (i = 0; i < pipe->buffers && len && entries; i++, len -= PAGE_SIZE) {
4160 ref = kzalloc(sizeof(*ref), GFP_KERNEL);
4165 ref->buffer = info->tr->buffer;
4166 ref->page = ring_buffer_alloc_read_page(ref->buffer, info->cpu);
4172 r = ring_buffer_read_page(ref->buffer, &ref->page,
4175 ring_buffer_free_read_page(ref->buffer, ref->page);
4181 * zero out any left over data, this is going to
4184 size = ring_buffer_page_len(ref->page);
4185 if (size < PAGE_SIZE)
4186 memset(ref->page + size, 0, PAGE_SIZE - size);
4188 page = virt_to_page(ref->page);
4190 spd.pages[i] = page;
4191 spd.partial[i].len = PAGE_SIZE;
4192 spd.partial[i].offset = 0;
4193 spd.partial[i].private = (unsigned long)ref;
4197 entries = ring_buffer_entries_cpu(info->tr->buffer, info->cpu);
4200 trace_access_unlock(info->cpu);
4203 /* did we read anything? */
4204 if (!spd.nr_pages) {
4205 if (flags & SPLICE_F_NONBLOCK)
4213 ret = splice_to_pipe(pipe, &spd);
4214 splice_shrink_spd(pipe, &spd);
4219 static const struct file_operations tracing_buffers_fops = {
4220 .open = tracing_buffers_open,
4221 .read = tracing_buffers_read,
4222 .release = tracing_buffers_release,
4223 .splice_read = tracing_buffers_splice_read,
4224 .llseek = no_llseek,
4228 tracing_stats_read(struct file *filp, char __user *ubuf,
4229 size_t count, loff_t *ppos)
4231 unsigned long cpu = (unsigned long)filp->private_data;
4232 struct trace_array *tr = &global_trace;
4233 struct trace_seq *s;
4235 unsigned long long t;
4236 unsigned long usec_rem;
4238 s = kmalloc(sizeof(*s), GFP_KERNEL);
4244 cnt = ring_buffer_entries_cpu(tr->buffer, cpu);
4245 trace_seq_printf(s, "entries: %ld\n", cnt);
4247 cnt = ring_buffer_overrun_cpu(tr->buffer, cpu);
4248 trace_seq_printf(s, "overrun: %ld\n", cnt);
4250 cnt = ring_buffer_commit_overrun_cpu(tr->buffer, cpu);
4251 trace_seq_printf(s, "commit overrun: %ld\n", cnt);
4253 cnt = ring_buffer_bytes_cpu(tr->buffer, cpu);
4254 trace_seq_printf(s, "bytes: %ld\n", cnt);
4256 t = ns2usecs(ring_buffer_oldest_event_ts(tr->buffer, cpu));
4257 usec_rem = do_div(t, USEC_PER_SEC);
4258 trace_seq_printf(s, "oldest event ts: %5llu.%06lu\n", t, usec_rem);
4260 t = ns2usecs(ring_buffer_time_stamp(tr->buffer, cpu));
4261 usec_rem = do_div(t, USEC_PER_SEC);
4262 trace_seq_printf(s, "now ts: %5llu.%06lu\n", t, usec_rem);
4264 count = simple_read_from_buffer(ubuf, count, ppos, s->buffer, s->len);
4271 static const struct file_operations tracing_stats_fops = {
4272 .open = tracing_open_generic,
4273 .read = tracing_stats_read,
4274 .llseek = generic_file_llseek,
4277 #ifdef CONFIG_DYNAMIC_FTRACE
4279 int __weak ftrace_arch_read_dyn_info(char *buf, int size)
4285 tracing_read_dyn_info(struct file *filp, char __user *ubuf,
4286 size_t cnt, loff_t *ppos)
4288 static char ftrace_dyn_info_buffer[1024];
4289 static DEFINE_MUTEX(dyn_info_mutex);
4290 unsigned long *p = filp->private_data;
4291 char *buf = ftrace_dyn_info_buffer;
4292 int size = ARRAY_SIZE(ftrace_dyn_info_buffer);
4295 mutex_lock(&dyn_info_mutex);
4296 r = sprintf(buf, "%ld ", *p);
4298 r += ftrace_arch_read_dyn_info(buf+r, (size-1)-r);
4301 r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
4303 mutex_unlock(&dyn_info_mutex);
4308 static const struct file_operations tracing_dyn_info_fops = {
4309 .open = tracing_open_generic,
4310 .read = tracing_read_dyn_info,
4311 .llseek = generic_file_llseek,
4315 static struct dentry *d_tracer;
4317 struct dentry *tracing_init_dentry(void)
4324 if (!debugfs_initialized())
4327 d_tracer = debugfs_create_dir("tracing", NULL);
4329 if (!d_tracer && !once) {
4331 pr_warning("Could not create debugfs directory 'tracing'\n");
4338 static struct dentry *d_percpu;
4340 struct dentry *tracing_dentry_percpu(void)
4343 struct dentry *d_tracer;
4348 d_tracer = tracing_init_dentry();
4353 d_percpu = debugfs_create_dir("per_cpu", d_tracer);
4355 if (!d_percpu && !once) {
4357 pr_warning("Could not create debugfs directory 'per_cpu'\n");
4364 static void tracing_init_debugfs_percpu(long cpu)
4366 struct dentry *d_percpu = tracing_dentry_percpu();
4367 struct dentry *d_cpu;
4368 char cpu_dir[30]; /* 30 characters should be more than enough */
4370 snprintf(cpu_dir, 30, "cpu%ld", cpu);
4371 d_cpu = debugfs_create_dir(cpu_dir, d_percpu);
4373 pr_warning("Could not create debugfs '%s' entry\n", cpu_dir);
4377 /* per cpu trace_pipe */
4378 trace_create_file("trace_pipe", 0444, d_cpu,
4379 (void *) cpu, &tracing_pipe_fops);
4382 trace_create_file("trace", 0644, d_cpu,
4383 (void *) cpu, &tracing_fops);
4385 trace_create_file("trace_pipe_raw", 0444, d_cpu,
4386 (void *) cpu, &tracing_buffers_fops);
4388 trace_create_file("stats", 0444, d_cpu,
4389 (void *) cpu, &tracing_stats_fops);
4392 #ifdef CONFIG_FTRACE_SELFTEST
4393 /* Let selftest have access to static functions in this file */
4394 #include "trace_selftest.c"
4397 struct trace_option_dentry {
4398 struct tracer_opt *opt;
4399 struct tracer_flags *flags;
4400 struct dentry *entry;
4404 trace_options_read(struct file *filp, char __user *ubuf, size_t cnt,
4407 struct trace_option_dentry *topt = filp->private_data;
4410 if (topt->flags->val & topt->opt->bit)
4415 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
4419 trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt,
4422 struct trace_option_dentry *topt = filp->private_data;
4426 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
4430 if (val != 0 && val != 1)
4433 if (!!(topt->flags->val & topt->opt->bit) != val) {
4434 mutex_lock(&trace_types_lock);
4435 ret = __set_tracer_option(current_trace, topt->flags,
4437 mutex_unlock(&trace_types_lock);
4448 static const struct file_operations trace_options_fops = {
4449 .open = tracing_open_generic,
4450 .read = trace_options_read,
4451 .write = trace_options_write,
4452 .llseek = generic_file_llseek,
4456 trace_options_core_read(struct file *filp, char __user *ubuf, size_t cnt,
4459 long index = (long)filp->private_data;
4462 if (trace_flags & (1 << index))
4467 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
4471 trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
4474 long index = (long)filp->private_data;
4478 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
4482 if (val != 0 && val != 1)
4484 set_tracer_flags(1 << index, val);
4491 static const struct file_operations trace_options_core_fops = {
4492 .open = tracing_open_generic,
4493 .read = trace_options_core_read,
4494 .write = trace_options_core_write,
4495 .llseek = generic_file_llseek,
4498 struct dentry *trace_create_file(const char *name,
4500 struct dentry *parent,
4502 const struct file_operations *fops)
4506 ret = debugfs_create_file(name, mode, parent, data, fops);
4508 pr_warning("Could not create debugfs '%s' entry\n", name);
4514 static struct dentry *trace_options_init_dentry(void)
4516 struct dentry *d_tracer;
4517 static struct dentry *t_options;
4522 d_tracer = tracing_init_dentry();
4526 t_options = debugfs_create_dir("options", d_tracer);
4528 pr_warning("Could not create debugfs directory 'options'\n");
4536 create_trace_option_file(struct trace_option_dentry *topt,
4537 struct tracer_flags *flags,
4538 struct tracer_opt *opt)
4540 struct dentry *t_options;
4542 t_options = trace_options_init_dentry();
4546 topt->flags = flags;
4549 topt->entry = trace_create_file(opt->name, 0644, t_options, topt,
4550 &trace_options_fops);
4554 static struct trace_option_dentry *
4555 create_trace_option_files(struct tracer *tracer)
4557 struct trace_option_dentry *topts;
4558 struct tracer_flags *flags;
4559 struct tracer_opt *opts;
4565 flags = tracer->flags;
4567 if (!flags || !flags->opts)
4572 for (cnt = 0; opts[cnt].name; cnt++)
4575 topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL);
4579 for (cnt = 0; opts[cnt].name; cnt++)
4580 create_trace_option_file(&topts[cnt], flags,
4587 destroy_trace_option_files(struct trace_option_dentry *topts)
4594 for (cnt = 0; topts[cnt].opt; cnt++) {
4595 if (topts[cnt].entry)
4596 debugfs_remove(topts[cnt].entry);
4602 static struct dentry *
4603 create_trace_option_core_file(const char *option, long index)
4605 struct dentry *t_options;
4607 t_options = trace_options_init_dentry();
4611 return trace_create_file(option, 0644, t_options, (void *)index,
4612 &trace_options_core_fops);
4615 static __init void create_trace_options_dir(void)
4617 struct dentry *t_options;
4620 t_options = trace_options_init_dentry();
4624 for (i = 0; trace_options[i]; i++)
4625 create_trace_option_core_file(trace_options[i], i);
4629 rb_simple_read(struct file *filp, char __user *ubuf,
4630 size_t cnt, loff_t *ppos)
4632 struct trace_array *tr = filp->private_data;
4633 struct ring_buffer *buffer = tr->buffer;
4638 r = ring_buffer_record_is_on(buffer);
4642 r = sprintf(buf, "%d\n", r);
4644 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
4648 rb_simple_write(struct file *filp, const char __user *ubuf,
4649 size_t cnt, loff_t *ppos)
4651 struct trace_array *tr = filp->private_data;
4652 struct ring_buffer *buffer = tr->buffer;
4656 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
4662 ring_buffer_record_on(buffer);
4664 ring_buffer_record_off(buffer);
4672 static const struct file_operations rb_simple_fops = {
4673 .open = tracing_open_generic,
4674 .read = rb_simple_read,
4675 .write = rb_simple_write,
4676 .llseek = default_llseek,
4679 static __init int tracer_init_debugfs(void)
4681 struct dentry *d_tracer;
4684 trace_access_lock_init();
4686 d_tracer = tracing_init_dentry();
4688 trace_create_file("tracing_enabled", 0644, d_tracer,
4689 &global_trace, &tracing_ctrl_fops);
4691 trace_create_file("trace_options", 0644, d_tracer,
4692 NULL, &tracing_iter_fops);
4694 trace_create_file("tracing_cpumask", 0644, d_tracer,
4695 NULL, &tracing_cpumask_fops);
4697 trace_create_file("trace", 0644, d_tracer,
4698 (void *) TRACE_PIPE_ALL_CPU, &tracing_fops);
4700 trace_create_file("available_tracers", 0444, d_tracer,
4701 &global_trace, &show_traces_fops);
4703 trace_create_file("current_tracer", 0644, d_tracer,
4704 &global_trace, &set_tracer_fops);
4706 #ifdef CONFIG_TRACER_MAX_TRACE
4707 trace_create_file("tracing_max_latency", 0644, d_tracer,
4708 &tracing_max_latency, &tracing_max_lat_fops);
4711 trace_create_file("tracing_thresh", 0644, d_tracer,
4712 &tracing_thresh, &tracing_max_lat_fops);
4714 trace_create_file("README", 0444, d_tracer,
4715 NULL, &tracing_readme_fops);
4717 trace_create_file("trace_pipe", 0444, d_tracer,
4718 (void *) TRACE_PIPE_ALL_CPU, &tracing_pipe_fops);
4720 trace_create_file("buffer_size_kb", 0644, d_tracer,
4721 &global_trace, &tracing_entries_fops);
4723 trace_create_file("buffer_total_size_kb", 0444, d_tracer,
4724 &global_trace, &tracing_total_entries_fops);
4726 trace_create_file("free_buffer", 0644, d_tracer,
4727 &global_trace, &tracing_free_buffer_fops);
4729 trace_create_file("trace_marker", 0220, d_tracer,
4730 NULL, &tracing_mark_fops);
4732 trace_create_file("saved_cmdlines", 0444, d_tracer,
4733 NULL, &tracing_saved_cmdlines_fops);
4735 trace_create_file("trace_clock", 0644, d_tracer, NULL,
4738 trace_create_file("tracing_on", 0644, d_tracer,
4739 &global_trace, &rb_simple_fops);
4741 #ifdef CONFIG_DYNAMIC_FTRACE
4742 trace_create_file("dyn_ftrace_total_info", 0444, d_tracer,
4743 &ftrace_update_tot_cnt, &tracing_dyn_info_fops);
4746 create_trace_options_dir();
4748 for_each_tracing_cpu(cpu)
4749 tracing_init_debugfs_percpu(cpu);
4754 static int trace_panic_handler(struct notifier_block *this,
4755 unsigned long event, void *unused)
4757 if (ftrace_dump_on_oops)
4758 ftrace_dump(ftrace_dump_on_oops);
4762 static struct notifier_block trace_panic_notifier = {
4763 .notifier_call = trace_panic_handler,
4765 .priority = 150 /* priority: INT_MAX >= x >= 0 */
4768 static int trace_die_handler(struct notifier_block *self,
4774 if (ftrace_dump_on_oops)
4775 ftrace_dump(ftrace_dump_on_oops);
4783 static struct notifier_block trace_die_notifier = {
4784 .notifier_call = trace_die_handler,
4789 * printk is set to max of 1024, we really don't need it that big.
4790 * Nothing should be printing 1000 characters anyway.
4792 #define TRACE_MAX_PRINT 1000
4795 * Define here KERN_TRACE so that we have one place to modify
4796 * it if we decide to change what log level the ftrace dump
4799 #define KERN_TRACE KERN_EMERG
4802 trace_printk_seq(struct trace_seq *s)
4804 /* Probably should print a warning here. */
4808 /* should be zero ended, but we are paranoid. */
4809 s->buffer[s->len] = 0;
4811 printk(KERN_TRACE "%s", s->buffer);
4816 void trace_init_global_iter(struct trace_iterator *iter)
4818 iter->tr = &global_trace;
4819 iter->trace = current_trace;
4820 iter->cpu_file = TRACE_PIPE_ALL_CPU;
4824 __ftrace_dump(bool disable_tracing, enum ftrace_dump_mode oops_dump_mode)
4826 static arch_spinlock_t ftrace_dump_lock =
4827 (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
4828 /* use static because iter can be a bit big for the stack */
4829 static struct trace_iterator iter;
4830 unsigned int old_userobj;
4831 static int dump_ran;
4832 unsigned long flags;
4836 local_irq_save(flags);
4837 arch_spin_lock(&ftrace_dump_lock);
4845 /* Did function tracer already get disabled? */
4846 if (ftrace_is_dead()) {
4847 printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
4848 printk("# MAY BE MISSING FUNCTION EVENTS\n");
4851 if (disable_tracing)
4854 trace_init_global_iter(&iter);
4856 for_each_tracing_cpu(cpu) {
4857 atomic_inc(&iter.tr->data[cpu]->disabled);
4860 old_userobj = trace_flags & TRACE_ITER_SYM_USEROBJ;
4862 /* don't look at user memory in panic mode */
4863 trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
4865 /* Simulate the iterator */
4866 iter.tr = &global_trace;
4867 iter.trace = current_trace;
4869 switch (oops_dump_mode) {
4871 iter.cpu_file = TRACE_PIPE_ALL_CPU;
4874 iter.cpu_file = raw_smp_processor_id();
4879 printk(KERN_TRACE "Bad dumping mode, switching to all CPUs dump\n");
4880 iter.cpu_file = TRACE_PIPE_ALL_CPU;
4883 printk(KERN_TRACE "Dumping ftrace buffer:\n");
4886 * We need to stop all tracing on all CPUS to read the
4887 * the next buffer. This is a bit expensive, but is
4888 * not done often. We fill all what we can read,
4889 * and then release the locks again.
4892 while (!trace_empty(&iter)) {
4895 printk(KERN_TRACE "---------------------------------\n");
4899 /* reset all but tr, trace, and overruns */
4900 memset(&iter.seq, 0,
4901 sizeof(struct trace_iterator) -
4902 offsetof(struct trace_iterator, seq));
4903 iter.iter_flags |= TRACE_FILE_LAT_FMT;
4906 if (trace_find_next_entry_inc(&iter) != NULL) {
4909 ret = print_trace_line(&iter);
4910 if (ret != TRACE_TYPE_NO_CONSUME)
4911 trace_consume(&iter);
4913 touch_nmi_watchdog();
4915 trace_printk_seq(&iter.seq);
4919 printk(KERN_TRACE " (ftrace buffer empty)\n");
4921 printk(KERN_TRACE "---------------------------------\n");
4924 /* Re-enable tracing if requested */
4925 if (!disable_tracing) {
4926 trace_flags |= old_userobj;
4928 for_each_tracing_cpu(cpu) {
4929 atomic_dec(&iter.tr->data[cpu]->disabled);
4935 arch_spin_unlock(&ftrace_dump_lock);
4936 local_irq_restore(flags);
4939 /* By default: disable tracing after the dump */
4940 void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
4942 __ftrace_dump(true, oops_dump_mode);
4944 EXPORT_SYMBOL_GPL(ftrace_dump);
4946 __init static int tracer_alloc_buffers(void)
4949 enum ring_buffer_flags rb_flags;
4954 if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
4957 if (!alloc_cpumask_var(&tracing_cpumask, GFP_KERNEL))
4958 goto out_free_buffer_mask;
4960 /* To save memory, keep the ring buffer size to its minimum */
4961 if (ring_buffer_expanded)
4962 ring_buf_size = trace_buf_size;
4966 rb_flags = trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0;
4968 cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
4969 cpumask_copy(tracing_cpumask, cpu_all_mask);
4971 /* TODO: make the number of buffers hot pluggable with CPUS */
4972 global_trace.buffer = ring_buffer_alloc(ring_buf_size, rb_flags);
4973 if (!global_trace.buffer) {
4974 printk(KERN_ERR "tracer: failed to allocate ring buffer!\n");
4976 goto out_free_cpumask;
4978 global_trace.entries = ring_buffer_size(global_trace.buffer);
4979 if (global_trace.buffer_disabled)
4983 #ifdef CONFIG_TRACER_MAX_TRACE
4984 max_tr.buffer = ring_buffer_alloc(1, rb_flags);
4985 if (!max_tr.buffer) {
4986 printk(KERN_ERR "tracer: failed to allocate max ring buffer!\n");
4988 ring_buffer_free(global_trace.buffer);
4989 goto out_free_cpumask;
4994 /* Allocate the first page for all buffers */
4995 for_each_tracing_cpu(i) {
4996 global_trace.data[i] = &per_cpu(global_trace_cpu, i);
4997 max_tr.data[i] = &per_cpu(max_tr_data, i);
5000 trace_init_cmdlines();
5002 register_tracer(&nop_trace);
5003 current_trace = &nop_trace;
5004 /* All seems OK, enable tracing */
5005 tracing_disabled = 0;
5007 atomic_notifier_chain_register(&panic_notifier_list,
5008 &trace_panic_notifier);
5010 register_die_notifier(&trace_die_notifier);
5015 free_cpumask_var(tracing_cpumask);
5016 out_free_buffer_mask:
5017 free_cpumask_var(tracing_buffer_mask);
5022 __init static int clear_boot_tracer(void)
5025 * The default tracer at boot buffer is an init section.
5026 * This function is called in lateinit. If we did not
5027 * find the boot tracer, then clear it out, to prevent
5028 * later registration from accessing the buffer that is
5029 * about to be freed.
5031 if (!default_bootup_tracer)
5034 printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n",
5035 default_bootup_tracer);
5036 default_bootup_tracer = NULL;
5041 early_initcall(tracer_alloc_buffers);
5042 fs_initcall(tracer_init_debugfs);
5043 late_initcall(clear_boot_tracer);