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>
42 #include "trace_output.h"
44 #define TRACE_BUFFER_FLAGS (RB_FL_OVERWRITE)
47 * On boot up, the ring buffer is set to the minimum size, so that
48 * we do not waste memory on systems that are not using tracing.
50 int ring_buffer_expanded;
53 * We need to change this state when a selftest is running.
54 * A selftest will lurk into the ring-buffer to count the
55 * entries inserted during the selftest although some concurrent
56 * insertions into the ring-buffer such as trace_printk could occurred
57 * at the same time, giving false positive or negative results.
59 static bool __read_mostly tracing_selftest_running;
62 * If a tracer is running, we do not want to run SELFTEST.
64 bool __read_mostly tracing_selftest_disabled;
66 /* For tracers that don't implement custom flags */
67 static struct tracer_opt dummy_tracer_opt[] = {
71 static struct tracer_flags dummy_tracer_flags = {
73 .opts = dummy_tracer_opt
76 static int dummy_set_flag(u32 old_flags, u32 bit, int set)
82 * Kill all tracing for good (never come back).
83 * It is initialized to 1 but will turn to zero if the initialization
84 * of the tracer is successful. But that is the only place that sets
87 static int tracing_disabled = 1;
89 DEFINE_PER_CPU(int, ftrace_cpu_disabled);
91 static inline void ftrace_disable_cpu(void)
94 __this_cpu_inc(ftrace_cpu_disabled);
97 static inline void ftrace_enable_cpu(void)
99 __this_cpu_dec(ftrace_cpu_disabled);
103 cpumask_var_t __read_mostly tracing_buffer_mask;
106 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
108 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
109 * is set, then ftrace_dump is called. This will output the contents
110 * of the ftrace buffers to the console. This is very useful for
111 * capturing traces that lead to crashes and outputing it to a
114 * It is default off, but you can enable it with either specifying
115 * "ftrace_dump_on_oops" in the kernel command line, or setting
116 * /proc/sys/kernel/ftrace_dump_on_oops
117 * Set 1 if you want to dump buffers of all CPUs
118 * Set 2 if you want to dump the buffer of the CPU that triggered oops
121 enum ftrace_dump_mode ftrace_dump_on_oops;
123 static int tracing_set_tracer(const char *buf);
125 #define MAX_TRACER_SIZE 100
126 static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata;
127 static char *default_bootup_tracer;
129 static int __init set_cmdline_ftrace(char *str)
131 strncpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
132 default_bootup_tracer = bootup_tracer_buf;
133 /* We are using ftrace early, expand it */
134 ring_buffer_expanded = 1;
137 __setup("ftrace=", set_cmdline_ftrace);
139 static int __init set_ftrace_dump_on_oops(char *str)
141 if (*str++ != '=' || !*str) {
142 ftrace_dump_on_oops = DUMP_ALL;
146 if (!strcmp("orig_cpu", str)) {
147 ftrace_dump_on_oops = DUMP_ORIG;
153 __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
155 unsigned long long ns2usecs(cycle_t nsec)
163 * The global_trace is the descriptor that holds the tracing
164 * buffers for the live tracing. For each CPU, it contains
165 * a link list of pages that will store trace entries. The
166 * page descriptor of the pages in the memory is used to hold
167 * the link list by linking the lru item in the page descriptor
168 * to each of the pages in the buffer per CPU.
170 * For each active CPU there is a data field that holds the
171 * pages for the buffer for that CPU. Each CPU has the same number
172 * of pages allocated for its buffer.
174 static struct trace_array global_trace;
176 static DEFINE_PER_CPU(struct trace_array_cpu, global_trace_cpu);
178 int filter_current_check_discard(struct ring_buffer *buffer,
179 struct ftrace_event_call *call, void *rec,
180 struct ring_buffer_event *event)
182 return filter_check_discard(call, rec, buffer, event);
184 EXPORT_SYMBOL_GPL(filter_current_check_discard);
186 cycle_t ftrace_now(int cpu)
190 /* Early boot up does not have a buffer yet */
191 if (!global_trace.buffer)
192 return trace_clock_local();
194 ts = ring_buffer_time_stamp(global_trace.buffer, cpu);
195 ring_buffer_normalize_time_stamp(global_trace.buffer, cpu, &ts);
201 * The max_tr is used to snapshot the global_trace when a maximum
202 * latency is reached. Some tracers will use this to store a maximum
203 * trace while it continues examining live traces.
205 * The buffers for the max_tr are set up the same as the global_trace.
206 * When a snapshot is taken, the link list of the max_tr is swapped
207 * with the link list of the global_trace and the buffers are reset for
208 * the global_trace so the tracing can continue.
210 static struct trace_array max_tr;
212 static DEFINE_PER_CPU(struct trace_array_cpu, max_tr_data);
214 /* tracer_enabled is used to toggle activation of a tracer */
215 static int tracer_enabled = 1;
218 * tracing_is_enabled - return tracer_enabled status
220 * This function is used by other tracers to know the status
221 * of the tracer_enabled flag. Tracers may use this function
222 * to know if it should enable their features when starting
223 * up. See irqsoff tracer for an example (start_irqsoff_tracer).
225 int tracing_is_enabled(void)
227 return tracer_enabled;
231 * trace_buf_size is the size in bytes that is allocated
232 * for a buffer. Note, the number of bytes is always rounded
235 * This number is purposely set to a low number of 16384.
236 * If the dump on oops happens, it will be much appreciated
237 * to not have to wait for all that output. Anyway this can be
238 * boot time and run time configurable.
240 #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
242 static unsigned long trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
244 /* trace_types holds a link list of available tracers. */
245 static struct tracer *trace_types __read_mostly;
247 /* current_trace points to the tracer that is currently active */
248 static struct tracer *current_trace __read_mostly;
251 * trace_types_lock is used to protect the trace_types list.
253 static DEFINE_MUTEX(trace_types_lock);
256 * serialize the access of the ring buffer
258 * ring buffer serializes readers, but it is low level protection.
259 * The validity of the events (which returns by ring_buffer_peek() ..etc)
260 * are not protected by ring buffer.
262 * The content of events may become garbage if we allow other process consumes
263 * these events concurrently:
264 * A) the page of the consumed events may become a normal page
265 * (not reader page) in ring buffer, and this page will be rewrited
266 * by events producer.
267 * B) The page of the consumed events may become a page for splice_read,
268 * and this page will be returned to system.
270 * These primitives allow multi process access to different cpu ring buffer
273 * These primitives don't distinguish read-only and read-consume access.
274 * Multi read-only access are also serialized.
278 static DECLARE_RWSEM(all_cpu_access_lock);
279 static DEFINE_PER_CPU(struct mutex, cpu_access_lock);
281 static inline void trace_access_lock(int cpu)
283 if (cpu == TRACE_PIPE_ALL_CPU) {
284 /* gain it for accessing the whole ring buffer. */
285 down_write(&all_cpu_access_lock);
287 /* gain it for accessing a cpu ring buffer. */
289 /* Firstly block other trace_access_lock(TRACE_PIPE_ALL_CPU). */
290 down_read(&all_cpu_access_lock);
292 /* Secondly block other access to this @cpu ring buffer. */
293 mutex_lock(&per_cpu(cpu_access_lock, cpu));
297 static inline void trace_access_unlock(int cpu)
299 if (cpu == TRACE_PIPE_ALL_CPU) {
300 up_write(&all_cpu_access_lock);
302 mutex_unlock(&per_cpu(cpu_access_lock, cpu));
303 up_read(&all_cpu_access_lock);
307 static inline void trace_access_lock_init(void)
311 for_each_possible_cpu(cpu)
312 mutex_init(&per_cpu(cpu_access_lock, cpu));
317 static DEFINE_MUTEX(access_lock);
319 static inline void trace_access_lock(int cpu)
322 mutex_lock(&access_lock);
325 static inline void trace_access_unlock(int cpu)
328 mutex_unlock(&access_lock);
331 static inline void trace_access_lock_init(void)
337 /* trace_wait is a waitqueue for tasks blocked on trace_poll */
338 static DECLARE_WAIT_QUEUE_HEAD(trace_wait);
340 /* trace_flags holds trace_options default values */
341 unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK |
342 TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | TRACE_ITER_SLEEP_TIME |
343 TRACE_ITER_GRAPH_TIME | TRACE_ITER_RECORD_CMD;
345 static int trace_stop_count;
346 static DEFINE_SPINLOCK(tracing_start_lock);
349 * trace_wake_up - wake up tasks waiting for trace input
351 * Simply wakes up any task that is blocked on the trace_wait
352 * queue. These is used with trace_poll for tasks polling the trace.
354 void trace_wake_up(void)
358 if (trace_flags & TRACE_ITER_BLOCK)
361 * The runqueue_is_locked() can fail, but this is the best we
365 if (!runqueue_is_locked(cpu))
366 wake_up(&trace_wait);
370 static int __init set_buf_size(char *str)
372 unsigned long buf_size;
376 buf_size = memparse(str, &str);
377 /* nr_entries can not be zero */
380 trace_buf_size = buf_size;
383 __setup("trace_buf_size=", set_buf_size);
385 static int __init set_tracing_thresh(char *str)
387 unsigned long threshhold;
392 ret = strict_strtoul(str, 0, &threshhold);
395 tracing_thresh = threshhold * 1000;
398 __setup("tracing_thresh=", set_tracing_thresh);
400 unsigned long nsecs_to_usecs(unsigned long nsecs)
405 /* These must match the bit postions in trace_iterator_flags */
406 static const char *trace_options[] = {
435 { trace_clock_local, "local" },
436 { trace_clock_global, "global" },
442 * trace_parser_get_init - gets the buffer for trace parser
444 int trace_parser_get_init(struct trace_parser *parser, int size)
446 memset(parser, 0, sizeof(*parser));
448 parser->buffer = kmalloc(size, GFP_KERNEL);
457 * trace_parser_put - frees the buffer for trace parser
459 void trace_parser_put(struct trace_parser *parser)
461 kfree(parser->buffer);
465 * trace_get_user - reads the user input string separated by space
466 * (matched by isspace(ch))
468 * For each string found the 'struct trace_parser' is updated,
469 * and the function returns.
471 * Returns number of bytes read.
473 * See kernel/trace/trace.h for 'struct trace_parser' details.
475 int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
476 size_t cnt, loff_t *ppos)
483 trace_parser_clear(parser);
485 ret = get_user(ch, ubuf++);
493 * The parser is not finished with the last write,
494 * continue reading the user input without skipping spaces.
497 /* skip white space */
498 while (cnt && isspace(ch)) {
499 ret = get_user(ch, ubuf++);
506 /* only spaces were written */
516 /* read the non-space input */
517 while (cnt && !isspace(ch)) {
518 if (parser->idx < parser->size - 1)
519 parser->buffer[parser->idx++] = ch;
524 ret = get_user(ch, ubuf++);
531 /* We either got finished input or we have to wait for another call. */
533 parser->buffer[parser->idx] = 0;
534 parser->cont = false;
537 parser->buffer[parser->idx++] = ch;
547 ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
555 if (s->len <= s->readpos)
558 len = s->len - s->readpos;
561 ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
571 static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
576 if (s->len <= s->readpos)
579 len = s->len - s->readpos;
582 ret = memcpy(buf, s->buffer + s->readpos, cnt);
591 * ftrace_max_lock is used to protect the swapping of buffers
592 * when taking a max snapshot. The buffers themselves are
593 * protected by per_cpu spinlocks. But the action of the swap
594 * needs its own lock.
596 * This is defined as a arch_spinlock_t in order to help
597 * with performance when lockdep debugging is enabled.
599 * It is also used in other places outside the update_max_tr
600 * so it needs to be defined outside of the
601 * CONFIG_TRACER_MAX_TRACE.
603 static arch_spinlock_t ftrace_max_lock =
604 (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
606 unsigned long __read_mostly tracing_thresh;
608 #ifdef CONFIG_TRACER_MAX_TRACE
609 unsigned long __read_mostly tracing_max_latency;
612 * Copy the new maximum trace into the separate maximum-trace
613 * structure. (this way the maximum trace is permanently saved,
614 * for later retrieval via /sys/kernel/debug/tracing/latency_trace)
617 __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
619 struct trace_array_cpu *data = tr->data[cpu];
620 struct trace_array_cpu *max_data;
623 max_tr.time_start = data->preempt_timestamp;
625 max_data = max_tr.data[cpu];
626 max_data->saved_latency = tracing_max_latency;
627 max_data->critical_start = data->critical_start;
628 max_data->critical_end = data->critical_end;
630 memcpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
631 max_data->pid = tsk->pid;
632 max_data->uid = task_uid(tsk);
633 max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
634 max_data->policy = tsk->policy;
635 max_data->rt_priority = tsk->rt_priority;
637 /* record this tasks comm */
638 tracing_record_cmdline(tsk);
642 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
644 * @tsk: the task with the latency
645 * @cpu: The cpu that initiated the trace.
647 * Flip the buffers between the @tr and the max_tr and record information
648 * about which task was the cause of this latency.
651 update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
653 struct ring_buffer *buf = tr->buffer;
655 if (trace_stop_count)
658 WARN_ON_ONCE(!irqs_disabled());
659 if (!current_trace->use_max_tr) {
663 arch_spin_lock(&ftrace_max_lock);
665 tr->buffer = max_tr.buffer;
668 __update_max_tr(tr, tsk, cpu);
669 arch_spin_unlock(&ftrace_max_lock);
673 * update_max_tr_single - only copy one trace over, and reset the rest
675 * @tsk - task with the latency
676 * @cpu - the cpu of the buffer to copy.
678 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
681 update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
685 if (trace_stop_count)
688 WARN_ON_ONCE(!irqs_disabled());
689 if (!current_trace->use_max_tr) {
694 arch_spin_lock(&ftrace_max_lock);
696 ftrace_disable_cpu();
698 ret = ring_buffer_swap_cpu(max_tr.buffer, tr->buffer, cpu);
702 * We failed to swap the buffer due to a commit taking
703 * place on this CPU. We fail to record, but we reset
704 * the max trace buffer (no one writes directly to it)
705 * and flag that it failed.
707 trace_array_printk(&max_tr, _THIS_IP_,
708 "Failed to swap buffers due to commit in progress\n");
713 WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);
715 __update_max_tr(tr, tsk, cpu);
716 arch_spin_unlock(&ftrace_max_lock);
718 #endif /* CONFIG_TRACER_MAX_TRACE */
721 * register_tracer - register a tracer with the ftrace system.
722 * @type - the plugin for the tracer
724 * Register a new plugin tracer.
726 int register_tracer(struct tracer *type)
727 __releases(kernel_lock)
728 __acquires(kernel_lock)
734 pr_info("Tracer must have a name\n");
738 if (strlen(type->name) >= MAX_TRACER_SIZE) {
739 pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE);
743 mutex_lock(&trace_types_lock);
745 tracing_selftest_running = true;
747 for (t = trace_types; t; t = t->next) {
748 if (strcmp(type->name, t->name) == 0) {
750 pr_info("Tracer %s already registered\n",
758 type->set_flag = &dummy_set_flag;
760 type->flags = &dummy_tracer_flags;
762 if (!type->flags->opts)
763 type->flags->opts = dummy_tracer_opt;
764 if (!type->wait_pipe)
765 type->wait_pipe = default_wait_pipe;
768 #ifdef CONFIG_FTRACE_STARTUP_TEST
769 if (type->selftest && !tracing_selftest_disabled) {
770 struct tracer *saved_tracer = current_trace;
771 struct trace_array *tr = &global_trace;
774 * Run a selftest on this tracer.
775 * Here we reset the trace buffer, and set the current
776 * tracer to be this tracer. The tracer can then run some
777 * internal tracing to verify that everything is in order.
778 * If we fail, we do not register this tracer.
780 tracing_reset_online_cpus(tr);
782 current_trace = type;
783 /* the test is responsible for initializing and enabling */
784 pr_info("Testing tracer %s: ", type->name);
785 ret = type->selftest(type, tr);
786 /* the test is responsible for resetting too */
787 current_trace = saved_tracer;
789 printk(KERN_CONT "FAILED!\n");
792 /* Only reset on passing, to avoid touching corrupted buffers */
793 tracing_reset_online_cpus(tr);
795 printk(KERN_CONT "PASSED\n");
799 type->next = trace_types;
803 tracing_selftest_running = false;
804 mutex_unlock(&trace_types_lock);
806 if (ret || !default_bootup_tracer)
809 if (strncmp(default_bootup_tracer, type->name, MAX_TRACER_SIZE))
812 printk(KERN_INFO "Starting tracer '%s'\n", type->name);
813 /* Do we want this tracer to start on bootup? */
814 tracing_set_tracer(type->name);
815 default_bootup_tracer = NULL;
816 /* disable other selftests, since this will break it. */
817 tracing_selftest_disabled = 1;
818 #ifdef CONFIG_FTRACE_STARTUP_TEST
819 printk(KERN_INFO "Disabling FTRACE selftests due to running tracer '%s'\n",
827 void unregister_tracer(struct tracer *type)
831 mutex_lock(&trace_types_lock);
832 for (t = &trace_types; *t; t = &(*t)->next) {
836 pr_info("Tracer %s not registered\n", type->name);
842 if (type == current_trace && tracer_enabled) {
845 if (current_trace->stop)
846 current_trace->stop(&global_trace);
847 current_trace = &nop_trace;
850 mutex_unlock(&trace_types_lock);
853 static void __tracing_reset(struct ring_buffer *buffer, int cpu)
855 ftrace_disable_cpu();
856 ring_buffer_reset_cpu(buffer, cpu);
860 void tracing_reset(struct trace_array *tr, int cpu)
862 struct ring_buffer *buffer = tr->buffer;
864 ring_buffer_record_disable(buffer);
866 /* Make sure all commits have finished */
868 __tracing_reset(buffer, cpu);
870 ring_buffer_record_enable(buffer);
873 void tracing_reset_online_cpus(struct trace_array *tr)
875 struct ring_buffer *buffer = tr->buffer;
878 ring_buffer_record_disable(buffer);
880 /* Make sure all commits have finished */
883 tr->time_start = ftrace_now(tr->cpu);
885 for_each_online_cpu(cpu)
886 __tracing_reset(buffer, cpu);
888 ring_buffer_record_enable(buffer);
891 void tracing_reset_current(int cpu)
893 tracing_reset(&global_trace, cpu);
896 void tracing_reset_current_online_cpus(void)
898 tracing_reset_online_cpus(&global_trace);
901 #define SAVED_CMDLINES 128
902 #define NO_CMDLINE_MAP UINT_MAX
903 static unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
904 static unsigned map_cmdline_to_pid[SAVED_CMDLINES];
905 static char saved_cmdlines[SAVED_CMDLINES][TASK_COMM_LEN];
906 static int cmdline_idx;
907 static arch_spinlock_t trace_cmdline_lock = __ARCH_SPIN_LOCK_UNLOCKED;
909 /* temporary disable recording */
910 static atomic_t trace_record_cmdline_disabled __read_mostly;
912 static void trace_init_cmdlines(void)
914 memset(&map_pid_to_cmdline, NO_CMDLINE_MAP, sizeof(map_pid_to_cmdline));
915 memset(&map_cmdline_to_pid, NO_CMDLINE_MAP, sizeof(map_cmdline_to_pid));
919 int is_tracing_stopped(void)
921 return trace_stop_count;
925 * ftrace_off_permanent - disable all ftrace code permanently
927 * This should only be called when a serious anomally has
928 * been detected. This will turn off the function tracing,
929 * ring buffers, and other tracing utilites. It takes no
930 * locks and can be called from any context.
932 void ftrace_off_permanent(void)
934 tracing_disabled = 1;
936 tracing_off_permanent();
940 * tracing_start - quick start of the tracer
942 * If tracing is enabled but was stopped by tracing_stop,
943 * this will start the tracer back up.
945 void tracing_start(void)
947 struct ring_buffer *buffer;
950 if (tracing_disabled)
953 spin_lock_irqsave(&tracing_start_lock, flags);
954 if (--trace_stop_count) {
955 if (trace_stop_count < 0) {
956 /* Someone screwed up their debugging */
958 trace_stop_count = 0;
963 /* Prevent the buffers from switching */
964 arch_spin_lock(&ftrace_max_lock);
966 buffer = global_trace.buffer;
968 ring_buffer_record_enable(buffer);
970 buffer = max_tr.buffer;
972 ring_buffer_record_enable(buffer);
974 arch_spin_unlock(&ftrace_max_lock);
978 spin_unlock_irqrestore(&tracing_start_lock, flags);
982 * tracing_stop - quick stop of the tracer
984 * Light weight way to stop tracing. Use in conjunction with
987 void tracing_stop(void)
989 struct ring_buffer *buffer;
993 spin_lock_irqsave(&tracing_start_lock, flags);
994 if (trace_stop_count++)
997 /* Prevent the buffers from switching */
998 arch_spin_lock(&ftrace_max_lock);
1000 buffer = global_trace.buffer;
1002 ring_buffer_record_disable(buffer);
1004 buffer = max_tr.buffer;
1006 ring_buffer_record_disable(buffer);
1008 arch_spin_unlock(&ftrace_max_lock);
1011 spin_unlock_irqrestore(&tracing_start_lock, flags);
1014 void trace_stop_cmdline_recording(void);
1016 static void trace_save_cmdline(struct task_struct *tsk)
1020 if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT))
1024 * It's not the end of the world if we don't get
1025 * the lock, but we also don't want to spin
1026 * nor do we want to disable interrupts,
1027 * so if we miss here, then better luck next time.
1029 if (!arch_spin_trylock(&trace_cmdline_lock))
1032 idx = map_pid_to_cmdline[tsk->pid];
1033 if (idx == NO_CMDLINE_MAP) {
1034 idx = (cmdline_idx + 1) % SAVED_CMDLINES;
1037 * Check whether the cmdline buffer at idx has a pid
1038 * mapped. We are going to overwrite that entry so we
1039 * need to clear the map_pid_to_cmdline. Otherwise we
1040 * would read the new comm for the old pid.
1042 pid = map_cmdline_to_pid[idx];
1043 if (pid != NO_CMDLINE_MAP)
1044 map_pid_to_cmdline[pid] = NO_CMDLINE_MAP;
1046 map_cmdline_to_pid[idx] = tsk->pid;
1047 map_pid_to_cmdline[tsk->pid] = idx;
1052 memcpy(&saved_cmdlines[idx], tsk->comm, TASK_COMM_LEN);
1054 arch_spin_unlock(&trace_cmdline_lock);
1057 void trace_find_cmdline(int pid, char comm[])
1062 strcpy(comm, "<idle>");
1066 if (WARN_ON_ONCE(pid < 0)) {
1067 strcpy(comm, "<XXX>");
1071 if (pid > PID_MAX_DEFAULT) {
1072 strcpy(comm, "<...>");
1077 arch_spin_lock(&trace_cmdline_lock);
1078 map = map_pid_to_cmdline[pid];
1079 if (map != NO_CMDLINE_MAP)
1080 strcpy(comm, saved_cmdlines[map]);
1082 strcpy(comm, "<...>");
1084 arch_spin_unlock(&trace_cmdline_lock);
1088 void tracing_record_cmdline(struct task_struct *tsk)
1090 if (atomic_read(&trace_record_cmdline_disabled) || !tracer_enabled ||
1094 trace_save_cmdline(tsk);
1098 tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
1101 struct task_struct *tsk = current;
1103 entry->preempt_count = pc & 0xff;
1104 entry->pid = (tsk) ? tsk->pid : 0;
1105 entry->lock_depth = (tsk) ? tsk->lock_depth : 0;
1107 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
1108 (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
1110 TRACE_FLAG_IRQS_NOSUPPORT |
1112 ((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
1113 ((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
1114 (need_resched() ? TRACE_FLAG_NEED_RESCHED : 0);
1116 EXPORT_SYMBOL_GPL(tracing_generic_entry_update);
1118 struct ring_buffer_event *
1119 trace_buffer_lock_reserve(struct ring_buffer *buffer,
1122 unsigned long flags, int pc)
1124 struct ring_buffer_event *event;
1126 event = ring_buffer_lock_reserve(buffer, len);
1127 if (event != NULL) {
1128 struct trace_entry *ent = ring_buffer_event_data(event);
1130 tracing_generic_entry_update(ent, flags, pc);
1138 __trace_buffer_unlock_commit(struct ring_buffer *buffer,
1139 struct ring_buffer_event *event,
1140 unsigned long flags, int pc,
1143 ring_buffer_unlock_commit(buffer, event);
1145 ftrace_trace_stack(buffer, flags, 6, pc);
1146 ftrace_trace_userstack(buffer, flags, pc);
1152 void trace_buffer_unlock_commit(struct ring_buffer *buffer,
1153 struct ring_buffer_event *event,
1154 unsigned long flags, int pc)
1156 __trace_buffer_unlock_commit(buffer, event, flags, pc, 1);
1159 struct ring_buffer_event *
1160 trace_current_buffer_lock_reserve(struct ring_buffer **current_rb,
1161 int type, unsigned long len,
1162 unsigned long flags, int pc)
1164 *current_rb = global_trace.buffer;
1165 return trace_buffer_lock_reserve(*current_rb,
1166 type, len, flags, pc);
1168 EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve);
1170 void trace_current_buffer_unlock_commit(struct ring_buffer *buffer,
1171 struct ring_buffer_event *event,
1172 unsigned long flags, int pc)
1174 __trace_buffer_unlock_commit(buffer, event, flags, pc, 1);
1176 EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit);
1178 void trace_nowake_buffer_unlock_commit(struct ring_buffer *buffer,
1179 struct ring_buffer_event *event,
1180 unsigned long flags, int pc)
1182 __trace_buffer_unlock_commit(buffer, event, flags, pc, 0);
1184 EXPORT_SYMBOL_GPL(trace_nowake_buffer_unlock_commit);
1186 void trace_current_buffer_discard_commit(struct ring_buffer *buffer,
1187 struct ring_buffer_event *event)
1189 ring_buffer_discard_commit(buffer, event);
1191 EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit);
1194 trace_function(struct trace_array *tr,
1195 unsigned long ip, unsigned long parent_ip, unsigned long flags,
1198 struct ftrace_event_call *call = &event_function;
1199 struct ring_buffer *buffer = tr->buffer;
1200 struct ring_buffer_event *event;
1201 struct ftrace_entry *entry;
1203 /* If we are reading the ring buffer, don't trace */
1204 if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))
1207 event = trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
1211 entry = ring_buffer_event_data(event);
1213 entry->parent_ip = parent_ip;
1215 if (!filter_check_discard(call, entry, buffer, event))
1216 ring_buffer_unlock_commit(buffer, event);
1220 ftrace(struct trace_array *tr, struct trace_array_cpu *data,
1221 unsigned long ip, unsigned long parent_ip, unsigned long flags,
1224 if (likely(!atomic_read(&data->disabled)))
1225 trace_function(tr, ip, parent_ip, flags, pc);
1228 #ifdef CONFIG_STACKTRACE
1229 static void __ftrace_trace_stack(struct ring_buffer *buffer,
1230 unsigned long flags,
1233 struct ftrace_event_call *call = &event_kernel_stack;
1234 struct ring_buffer_event *event;
1235 struct stack_entry *entry;
1236 struct stack_trace trace;
1238 event = trace_buffer_lock_reserve(buffer, TRACE_STACK,
1239 sizeof(*entry), flags, pc);
1242 entry = ring_buffer_event_data(event);
1243 memset(&entry->caller, 0, sizeof(entry->caller));
1245 trace.nr_entries = 0;
1246 trace.max_entries = FTRACE_STACK_ENTRIES;
1248 trace.entries = entry->caller;
1250 save_stack_trace(&trace);
1251 if (!filter_check_discard(call, entry, buffer, event))
1252 ring_buffer_unlock_commit(buffer, event);
1255 void ftrace_trace_stack(struct ring_buffer *buffer, unsigned long flags,
1258 if (!(trace_flags & TRACE_ITER_STACKTRACE))
1261 __ftrace_trace_stack(buffer, flags, skip, pc);
1264 void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
1267 __ftrace_trace_stack(tr->buffer, flags, skip, pc);
1271 * trace_dump_stack - record a stack back trace in the trace buffer
1273 void trace_dump_stack(void)
1275 unsigned long flags;
1277 if (tracing_disabled || tracing_selftest_running)
1280 local_save_flags(flags);
1282 /* skipping 3 traces, seems to get us at the caller of this function */
1283 __ftrace_trace_stack(global_trace.buffer, flags, 3, preempt_count());
1286 static DEFINE_PER_CPU(int, user_stack_count);
1289 ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
1291 struct ftrace_event_call *call = &event_user_stack;
1292 struct ring_buffer_event *event;
1293 struct userstack_entry *entry;
1294 struct stack_trace trace;
1296 if (!(trace_flags & TRACE_ITER_USERSTACKTRACE))
1300 * NMIs can not handle page faults, even with fix ups.
1301 * The save user stack can (and often does) fault.
1303 if (unlikely(in_nmi()))
1307 * prevent recursion, since the user stack tracing may
1308 * trigger other kernel events.
1311 if (__this_cpu_read(user_stack_count))
1314 __this_cpu_inc(user_stack_count);
1316 event = trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
1317 sizeof(*entry), flags, pc);
1319 goto out_drop_count;
1320 entry = ring_buffer_event_data(event);
1322 entry->tgid = current->tgid;
1323 memset(&entry->caller, 0, sizeof(entry->caller));
1325 trace.nr_entries = 0;
1326 trace.max_entries = FTRACE_STACK_ENTRIES;
1328 trace.entries = entry->caller;
1330 save_stack_trace_user(&trace);
1331 if (!filter_check_discard(call, entry, buffer, event))
1332 ring_buffer_unlock_commit(buffer, event);
1335 __this_cpu_dec(user_stack_count);
1341 static void __trace_userstack(struct trace_array *tr, unsigned long flags)
1343 ftrace_trace_userstack(tr, flags, preempt_count());
1347 #endif /* CONFIG_STACKTRACE */
1350 * trace_vbprintk - write binary msg to tracing buffer
1353 int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
1355 static arch_spinlock_t trace_buf_lock =
1356 (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
1357 static u32 trace_buf[TRACE_BUF_SIZE];
1359 struct ftrace_event_call *call = &event_bprint;
1360 struct ring_buffer_event *event;
1361 struct ring_buffer *buffer;
1362 struct trace_array *tr = &global_trace;
1363 struct trace_array_cpu *data;
1364 struct bprint_entry *entry;
1365 unsigned long flags;
1367 int cpu, len = 0, size, pc;
1369 if (unlikely(tracing_selftest_running || tracing_disabled))
1372 /* Don't pollute graph traces with trace_vprintk internals */
1373 pause_graph_tracing();
1375 pc = preempt_count();
1376 preempt_disable_notrace();
1377 cpu = raw_smp_processor_id();
1378 data = tr->data[cpu];
1380 disable = atomic_inc_return(&data->disabled);
1381 if (unlikely(disable != 1))
1384 /* Lockdep uses trace_printk for lock tracing */
1385 local_irq_save(flags);
1386 arch_spin_lock(&trace_buf_lock);
1387 len = vbin_printf(trace_buf, TRACE_BUF_SIZE, fmt, args);
1389 if (len > TRACE_BUF_SIZE || len < 0)
1392 size = sizeof(*entry) + sizeof(u32) * len;
1393 buffer = tr->buffer;
1394 event = trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
1398 entry = ring_buffer_event_data(event);
1402 memcpy(entry->buf, trace_buf, sizeof(u32) * len);
1403 if (!filter_check_discard(call, entry, buffer, event)) {
1404 ring_buffer_unlock_commit(buffer, event);
1405 ftrace_trace_stack(buffer, flags, 6, pc);
1409 arch_spin_unlock(&trace_buf_lock);
1410 local_irq_restore(flags);
1413 atomic_dec_return(&data->disabled);
1414 preempt_enable_notrace();
1415 unpause_graph_tracing();
1419 EXPORT_SYMBOL_GPL(trace_vbprintk);
1421 int trace_array_printk(struct trace_array *tr,
1422 unsigned long ip, const char *fmt, ...)
1427 if (!(trace_flags & TRACE_ITER_PRINTK))
1431 ret = trace_array_vprintk(tr, ip, fmt, ap);
1436 int trace_array_vprintk(struct trace_array *tr,
1437 unsigned long ip, const char *fmt, va_list args)
1439 static arch_spinlock_t trace_buf_lock = __ARCH_SPIN_LOCK_UNLOCKED;
1440 static char trace_buf[TRACE_BUF_SIZE];
1442 struct ftrace_event_call *call = &event_print;
1443 struct ring_buffer_event *event;
1444 struct ring_buffer *buffer;
1445 struct trace_array_cpu *data;
1446 int cpu, len = 0, size, pc;
1447 struct print_entry *entry;
1448 unsigned long irq_flags;
1451 if (tracing_disabled || tracing_selftest_running)
1454 pc = preempt_count();
1455 preempt_disable_notrace();
1456 cpu = raw_smp_processor_id();
1457 data = tr->data[cpu];
1459 disable = atomic_inc_return(&data->disabled);
1460 if (unlikely(disable != 1))
1463 pause_graph_tracing();
1464 raw_local_irq_save(irq_flags);
1465 arch_spin_lock(&trace_buf_lock);
1466 len = vsnprintf(trace_buf, TRACE_BUF_SIZE, fmt, args);
1468 size = sizeof(*entry) + len + 1;
1469 buffer = tr->buffer;
1470 event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
1474 entry = ring_buffer_event_data(event);
1477 memcpy(&entry->buf, trace_buf, len);
1478 entry->buf[len] = '\0';
1479 if (!filter_check_discard(call, entry, buffer, event)) {
1480 ring_buffer_unlock_commit(buffer, event);
1481 ftrace_trace_stack(buffer, irq_flags, 6, pc);
1485 arch_spin_unlock(&trace_buf_lock);
1486 raw_local_irq_restore(irq_flags);
1487 unpause_graph_tracing();
1489 atomic_dec_return(&data->disabled);
1490 preempt_enable_notrace();
1495 int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
1497 return trace_array_vprintk(&global_trace, ip, fmt, args);
1499 EXPORT_SYMBOL_GPL(trace_vprintk);
1501 static void trace_iterator_increment(struct trace_iterator *iter)
1503 /* Don't allow ftrace to trace into the ring buffers */
1504 ftrace_disable_cpu();
1507 if (iter->buffer_iter[iter->cpu])
1508 ring_buffer_read(iter->buffer_iter[iter->cpu], NULL);
1510 ftrace_enable_cpu();
1513 static struct trace_entry *
1514 peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts,
1515 unsigned long *lost_events)
1517 struct ring_buffer_event *event;
1518 struct ring_buffer_iter *buf_iter = iter->buffer_iter[cpu];
1520 /* Don't allow ftrace to trace into the ring buffers */
1521 ftrace_disable_cpu();
1524 event = ring_buffer_iter_peek(buf_iter, ts);
1526 event = ring_buffer_peek(iter->tr->buffer, cpu, ts,
1529 ftrace_enable_cpu();
1531 return event ? ring_buffer_event_data(event) : NULL;
1534 static struct trace_entry *
1535 __find_next_entry(struct trace_iterator *iter, int *ent_cpu,
1536 unsigned long *missing_events, u64 *ent_ts)
1538 struct ring_buffer *buffer = iter->tr->buffer;
1539 struct trace_entry *ent, *next = NULL;
1540 unsigned long lost_events = 0, next_lost = 0;
1541 int cpu_file = iter->cpu_file;
1542 u64 next_ts = 0, ts;
1547 * If we are in a per_cpu trace file, don't bother by iterating over
1548 * all cpu and peek directly.
1550 if (cpu_file > TRACE_PIPE_ALL_CPU) {
1551 if (ring_buffer_empty_cpu(buffer, cpu_file))
1553 ent = peek_next_entry(iter, cpu_file, ent_ts, missing_events);
1555 *ent_cpu = cpu_file;
1560 for_each_tracing_cpu(cpu) {
1562 if (ring_buffer_empty_cpu(buffer, cpu))
1565 ent = peek_next_entry(iter, cpu, &ts, &lost_events);
1568 * Pick the entry with the smallest timestamp:
1570 if (ent && (!next || ts < next_ts)) {
1574 next_lost = lost_events;
1579 *ent_cpu = next_cpu;
1585 *missing_events = next_lost;
1590 /* Find the next real entry, without updating the iterator itself */
1591 struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
1592 int *ent_cpu, u64 *ent_ts)
1594 return __find_next_entry(iter, ent_cpu, NULL, ent_ts);
1597 /* Find the next real entry, and increment the iterator to the next entry */
1598 void *trace_find_next_entry_inc(struct trace_iterator *iter)
1600 iter->ent = __find_next_entry(iter, &iter->cpu,
1601 &iter->lost_events, &iter->ts);
1604 trace_iterator_increment(iter);
1606 return iter->ent ? iter : NULL;
1609 static void trace_consume(struct trace_iterator *iter)
1611 /* Don't allow ftrace to trace into the ring buffers */
1612 ftrace_disable_cpu();
1613 ring_buffer_consume(iter->tr->buffer, iter->cpu, &iter->ts,
1614 &iter->lost_events);
1615 ftrace_enable_cpu();
1618 static void *s_next(struct seq_file *m, void *v, loff_t *pos)
1620 struct trace_iterator *iter = m->private;
1624 WARN_ON_ONCE(iter->leftover);
1628 /* can't go backwards */
1633 ent = trace_find_next_entry_inc(iter);
1637 while (ent && iter->idx < i)
1638 ent = trace_find_next_entry_inc(iter);
1645 void tracing_iter_reset(struct trace_iterator *iter, int cpu)
1647 struct trace_array *tr = iter->tr;
1648 struct ring_buffer_event *event;
1649 struct ring_buffer_iter *buf_iter;
1650 unsigned long entries = 0;
1653 tr->data[cpu]->skipped_entries = 0;
1655 if (!iter->buffer_iter[cpu])
1658 buf_iter = iter->buffer_iter[cpu];
1659 ring_buffer_iter_reset(buf_iter);
1662 * We could have the case with the max latency tracers
1663 * that a reset never took place on a cpu. This is evident
1664 * by the timestamp being before the start of the buffer.
1666 while ((event = ring_buffer_iter_peek(buf_iter, &ts))) {
1667 if (ts >= iter->tr->time_start)
1670 ring_buffer_read(buf_iter, NULL);
1673 tr->data[cpu]->skipped_entries = entries;
1677 * The current tracer is copied to avoid a global locking
1680 static void *s_start(struct seq_file *m, loff_t *pos)
1682 struct trace_iterator *iter = m->private;
1683 static struct tracer *old_tracer;
1684 int cpu_file = iter->cpu_file;
1689 /* copy the tracer to avoid using a global lock all around */
1690 mutex_lock(&trace_types_lock);
1691 if (unlikely(old_tracer != current_trace && current_trace)) {
1692 old_tracer = current_trace;
1693 *iter->trace = *current_trace;
1695 mutex_unlock(&trace_types_lock);
1697 atomic_inc(&trace_record_cmdline_disabled);
1699 if (*pos != iter->pos) {
1704 ftrace_disable_cpu();
1706 if (cpu_file == TRACE_PIPE_ALL_CPU) {
1707 for_each_tracing_cpu(cpu)
1708 tracing_iter_reset(iter, cpu);
1710 tracing_iter_reset(iter, cpu_file);
1712 ftrace_enable_cpu();
1715 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
1720 * If we overflowed the seq_file before, then we want
1721 * to just reuse the trace_seq buffer again.
1727 p = s_next(m, p, &l);
1731 trace_event_read_lock();
1732 trace_access_lock(cpu_file);
1736 static void s_stop(struct seq_file *m, void *p)
1738 struct trace_iterator *iter = m->private;
1740 atomic_dec(&trace_record_cmdline_disabled);
1741 trace_access_unlock(iter->cpu_file);
1742 trace_event_read_unlock();
1745 static void print_lat_help_header(struct seq_file *m)
1747 seq_puts(m, "# _------=> CPU# \n");
1748 seq_puts(m, "# / _-----=> irqs-off \n");
1749 seq_puts(m, "# | / _----=> need-resched \n");
1750 seq_puts(m, "# || / _---=> hardirq/softirq \n");
1751 seq_puts(m, "# ||| / _--=> preempt-depth \n");
1752 seq_puts(m, "# |||| /_--=> lock-depth \n");
1753 seq_puts(m, "# |||||/ delay \n");
1754 seq_puts(m, "# cmd pid |||||| time | caller \n");
1755 seq_puts(m, "# \\ / |||||| \\ | / \n");
1758 static void print_func_help_header(struct seq_file *m)
1760 seq_puts(m, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
1761 seq_puts(m, "# | | | | |\n");
1766 print_trace_header(struct seq_file *m, struct trace_iterator *iter)
1768 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1769 struct trace_array *tr = iter->tr;
1770 struct trace_array_cpu *data = tr->data[tr->cpu];
1771 struct tracer *type = current_trace;
1772 unsigned long entries = 0;
1773 unsigned long total = 0;
1774 unsigned long count;
1775 const char *name = "preemption";
1782 for_each_tracing_cpu(cpu) {
1783 count = ring_buffer_entries_cpu(tr->buffer, cpu);
1785 * If this buffer has skipped entries, then we hold all
1786 * entries for the trace and we need to ignore the
1787 * ones before the time stamp.
1789 if (tr->data[cpu]->skipped_entries) {
1790 count -= tr->data[cpu]->skipped_entries;
1791 /* total is the same as the entries */
1795 ring_buffer_overrun_cpu(tr->buffer, cpu);
1799 seq_printf(m, "# %s latency trace v1.1.5 on %s\n",
1801 seq_puts(m, "# -----------------------------------"
1802 "---------------------------------\n");
1803 seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d |"
1804 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
1805 nsecs_to_usecs(data->saved_latency),
1809 #if defined(CONFIG_PREEMPT_NONE)
1811 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
1813 #elif defined(CONFIG_PREEMPT)
1818 /* These are reserved for later use */
1821 seq_printf(m, " #P:%d)\n", num_online_cpus());
1825 seq_puts(m, "# -----------------\n");
1826 seq_printf(m, "# | task: %.16s-%d "
1827 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
1828 data->comm, data->pid, data->uid, data->nice,
1829 data->policy, data->rt_priority);
1830 seq_puts(m, "# -----------------\n");
1832 if (data->critical_start) {
1833 seq_puts(m, "# => started at: ");
1834 seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
1835 trace_print_seq(m, &iter->seq);
1836 seq_puts(m, "\n# => ended at: ");
1837 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
1838 trace_print_seq(m, &iter->seq);
1839 seq_puts(m, "\n#\n");
1845 static void test_cpu_buff_start(struct trace_iterator *iter)
1847 struct trace_seq *s = &iter->seq;
1849 if (!(trace_flags & TRACE_ITER_ANNOTATE))
1852 if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
1855 if (cpumask_test_cpu(iter->cpu, iter->started))
1858 if (iter->tr->data[iter->cpu]->skipped_entries)
1861 cpumask_set_cpu(iter->cpu, iter->started);
1863 /* Don't print started cpu buffer for the first entry of the trace */
1865 trace_seq_printf(s, "##### CPU %u buffer started ####\n",
1869 static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
1871 struct trace_seq *s = &iter->seq;
1872 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1873 struct trace_entry *entry;
1874 struct trace_event *event;
1878 test_cpu_buff_start(iter);
1880 event = ftrace_find_event(entry->type);
1882 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1883 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
1884 if (!trace_print_lat_context(iter))
1887 if (!trace_print_context(iter))
1893 return event->funcs->trace(iter, sym_flags, event);
1895 if (!trace_seq_printf(s, "Unknown type %d\n", entry->type))
1898 return TRACE_TYPE_HANDLED;
1900 return TRACE_TYPE_PARTIAL_LINE;
1903 static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
1905 struct trace_seq *s = &iter->seq;
1906 struct trace_entry *entry;
1907 struct trace_event *event;
1911 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1912 if (!trace_seq_printf(s, "%d %d %llu ",
1913 entry->pid, iter->cpu, iter->ts))
1917 event = ftrace_find_event(entry->type);
1919 return event->funcs->raw(iter, 0, event);
1921 if (!trace_seq_printf(s, "%d ?\n", entry->type))
1924 return TRACE_TYPE_HANDLED;
1926 return TRACE_TYPE_PARTIAL_LINE;
1929 static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
1931 struct trace_seq *s = &iter->seq;
1932 unsigned char newline = '\n';
1933 struct trace_entry *entry;
1934 struct trace_event *event;
1938 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1939 SEQ_PUT_HEX_FIELD_RET(s, entry->pid);
1940 SEQ_PUT_HEX_FIELD_RET(s, iter->cpu);
1941 SEQ_PUT_HEX_FIELD_RET(s, iter->ts);
1944 event = ftrace_find_event(entry->type);
1946 enum print_line_t ret = event->funcs->hex(iter, 0, event);
1947 if (ret != TRACE_TYPE_HANDLED)
1951 SEQ_PUT_FIELD_RET(s, newline);
1953 return TRACE_TYPE_HANDLED;
1956 static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
1958 struct trace_seq *s = &iter->seq;
1959 struct trace_entry *entry;
1960 struct trace_event *event;
1964 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1965 SEQ_PUT_FIELD_RET(s, entry->pid);
1966 SEQ_PUT_FIELD_RET(s, iter->cpu);
1967 SEQ_PUT_FIELD_RET(s, iter->ts);
1970 event = ftrace_find_event(entry->type);
1971 return event ? event->funcs->binary(iter, 0, event) :
1975 int trace_empty(struct trace_iterator *iter)
1979 /* If we are looking at one CPU buffer, only check that one */
1980 if (iter->cpu_file != TRACE_PIPE_ALL_CPU) {
1981 cpu = iter->cpu_file;
1982 if (iter->buffer_iter[cpu]) {
1983 if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
1986 if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu))
1992 for_each_tracing_cpu(cpu) {
1993 if (iter->buffer_iter[cpu]) {
1994 if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
1997 if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu))
2005 /* Called with trace_event_read_lock() held. */
2006 enum print_line_t print_trace_line(struct trace_iterator *iter)
2008 enum print_line_t ret;
2010 if (iter->lost_events)
2011 trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
2012 iter->cpu, iter->lost_events);
2014 if (iter->trace && iter->trace->print_line) {
2015 ret = iter->trace->print_line(iter);
2016 if (ret != TRACE_TYPE_UNHANDLED)
2020 if (iter->ent->type == TRACE_BPRINT &&
2021 trace_flags & TRACE_ITER_PRINTK &&
2022 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
2023 return trace_print_bprintk_msg_only(iter);
2025 if (iter->ent->type == TRACE_PRINT &&
2026 trace_flags & TRACE_ITER_PRINTK &&
2027 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
2028 return trace_print_printk_msg_only(iter);
2030 if (trace_flags & TRACE_ITER_BIN)
2031 return print_bin_fmt(iter);
2033 if (trace_flags & TRACE_ITER_HEX)
2034 return print_hex_fmt(iter);
2036 if (trace_flags & TRACE_ITER_RAW)
2037 return print_raw_fmt(iter);
2039 return print_trace_fmt(iter);
2042 void trace_default_header(struct seq_file *m)
2044 struct trace_iterator *iter = m->private;
2046 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
2047 /* print nothing if the buffers are empty */
2048 if (trace_empty(iter))
2050 print_trace_header(m, iter);
2051 if (!(trace_flags & TRACE_ITER_VERBOSE))
2052 print_lat_help_header(m);
2054 if (!(trace_flags & TRACE_ITER_VERBOSE))
2055 print_func_help_header(m);
2059 static int s_show(struct seq_file *m, void *v)
2061 struct trace_iterator *iter = v;
2064 if (iter->ent == NULL) {
2066 seq_printf(m, "# tracer: %s\n", iter->trace->name);
2069 if (iter->trace && iter->trace->print_header)
2070 iter->trace->print_header(m);
2072 trace_default_header(m);
2074 } else if (iter->leftover) {
2076 * If we filled the seq_file buffer earlier, we
2077 * want to just show it now.
2079 ret = trace_print_seq(m, &iter->seq);
2081 /* ret should this time be zero, but you never know */
2082 iter->leftover = ret;
2085 print_trace_line(iter);
2086 ret = trace_print_seq(m, &iter->seq);
2088 * If we overflow the seq_file buffer, then it will
2089 * ask us for this data again at start up.
2091 * ret is 0 if seq_file write succeeded.
2094 iter->leftover = ret;
2100 static const struct seq_operations tracer_seq_ops = {
2107 static struct trace_iterator *
2108 __tracing_open(struct inode *inode, struct file *file)
2110 long cpu_file = (long) inode->i_private;
2111 void *fail_ret = ERR_PTR(-ENOMEM);
2112 struct trace_iterator *iter;
2116 if (tracing_disabled)
2117 return ERR_PTR(-ENODEV);
2119 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2121 return ERR_PTR(-ENOMEM);
2124 * We make a copy of the current tracer to avoid concurrent
2125 * changes on it while we are reading.
2127 mutex_lock(&trace_types_lock);
2128 iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL);
2133 *iter->trace = *current_trace;
2135 if (!zalloc_cpumask_var(&iter->started, GFP_KERNEL))
2138 if (current_trace && current_trace->print_max)
2141 iter->tr = &global_trace;
2143 mutex_init(&iter->mutex);
2144 iter->cpu_file = cpu_file;
2146 /* Notify the tracer early; before we stop tracing. */
2147 if (iter->trace && iter->trace->open)
2148 iter->trace->open(iter);
2150 /* Annotate start of buffers if we had overruns */
2151 if (ring_buffer_overruns(iter->tr->buffer))
2152 iter->iter_flags |= TRACE_FILE_ANNOTATE;
2154 /* stop the trace while dumping */
2157 if (iter->cpu_file == TRACE_PIPE_ALL_CPU) {
2158 for_each_tracing_cpu(cpu) {
2159 iter->buffer_iter[cpu] =
2160 ring_buffer_read_prepare(iter->tr->buffer, cpu);
2162 ring_buffer_read_prepare_sync();
2163 for_each_tracing_cpu(cpu) {
2164 ring_buffer_read_start(iter->buffer_iter[cpu]);
2165 tracing_iter_reset(iter, cpu);
2168 cpu = iter->cpu_file;
2169 iter->buffer_iter[cpu] =
2170 ring_buffer_read_prepare(iter->tr->buffer, cpu);
2171 ring_buffer_read_prepare_sync();
2172 ring_buffer_read_start(iter->buffer_iter[cpu]);
2173 tracing_iter_reset(iter, cpu);
2176 ret = seq_open(file, &tracer_seq_ops);
2178 fail_ret = ERR_PTR(ret);
2182 m = file->private_data;
2185 mutex_unlock(&trace_types_lock);
2190 for_each_tracing_cpu(cpu) {
2191 if (iter->buffer_iter[cpu])
2192 ring_buffer_read_finish(iter->buffer_iter[cpu]);
2194 free_cpumask_var(iter->started);
2197 mutex_unlock(&trace_types_lock);
2204 int tracing_open_generic(struct inode *inode, struct file *filp)
2206 if (tracing_disabled)
2209 filp->private_data = inode->i_private;
2213 static int tracing_release(struct inode *inode, struct file *file)
2215 struct seq_file *m = file->private_data;
2216 struct trace_iterator *iter;
2219 if (!(file->f_mode & FMODE_READ))
2224 mutex_lock(&trace_types_lock);
2225 for_each_tracing_cpu(cpu) {
2226 if (iter->buffer_iter[cpu])
2227 ring_buffer_read_finish(iter->buffer_iter[cpu]);
2230 if (iter->trace && iter->trace->close)
2231 iter->trace->close(iter);
2233 /* reenable tracing if it was previously enabled */
2235 mutex_unlock(&trace_types_lock);
2237 seq_release(inode, file);
2238 mutex_destroy(&iter->mutex);
2239 free_cpumask_var(iter->started);
2245 static int tracing_open(struct inode *inode, struct file *file)
2247 struct trace_iterator *iter;
2250 /* If this file was open for write, then erase contents */
2251 if ((file->f_mode & FMODE_WRITE) &&
2252 (file->f_flags & O_TRUNC)) {
2253 long cpu = (long) inode->i_private;
2255 if (cpu == TRACE_PIPE_ALL_CPU)
2256 tracing_reset_online_cpus(&global_trace);
2258 tracing_reset(&global_trace, cpu);
2261 if (file->f_mode & FMODE_READ) {
2262 iter = __tracing_open(inode, file);
2264 ret = PTR_ERR(iter);
2265 else if (trace_flags & TRACE_ITER_LATENCY_FMT)
2266 iter->iter_flags |= TRACE_FILE_LAT_FMT;
2272 t_next(struct seq_file *m, void *v, loff_t *pos)
2274 struct tracer *t = v;
2284 static void *t_start(struct seq_file *m, loff_t *pos)
2289 mutex_lock(&trace_types_lock);
2290 for (t = trace_types; t && l < *pos; t = t_next(m, t, &l))
2296 static void t_stop(struct seq_file *m, void *p)
2298 mutex_unlock(&trace_types_lock);
2301 static int t_show(struct seq_file *m, void *v)
2303 struct tracer *t = v;
2308 seq_printf(m, "%s", t->name);
2317 static const struct seq_operations show_traces_seq_ops = {
2324 static int show_traces_open(struct inode *inode, struct file *file)
2326 if (tracing_disabled)
2329 return seq_open(file, &show_traces_seq_ops);
2333 tracing_write_stub(struct file *filp, const char __user *ubuf,
2334 size_t count, loff_t *ppos)
2339 static loff_t tracing_seek(struct file *file, loff_t offset, int origin)
2341 if (file->f_mode & FMODE_READ)
2342 return seq_lseek(file, offset, origin);
2347 static const struct file_operations tracing_fops = {
2348 .open = tracing_open,
2350 .write = tracing_write_stub,
2351 .llseek = tracing_seek,
2352 .release = tracing_release,
2355 static const struct file_operations show_traces_fops = {
2356 .open = show_traces_open,
2358 .release = seq_release,
2359 .llseek = seq_lseek,
2363 * Only trace on a CPU if the bitmask is set:
2365 static cpumask_var_t tracing_cpumask;
2368 * The tracer itself will not take this lock, but still we want
2369 * to provide a consistent cpumask to user-space:
2371 static DEFINE_MUTEX(tracing_cpumask_update_lock);
2374 * Temporary storage for the character representation of the
2375 * CPU bitmask (and one more byte for the newline):
2377 static char mask_str[NR_CPUS + 1];
2380 tracing_cpumask_read(struct file *filp, char __user *ubuf,
2381 size_t count, loff_t *ppos)
2385 mutex_lock(&tracing_cpumask_update_lock);
2387 len = cpumask_scnprintf(mask_str, count, tracing_cpumask);
2388 if (count - len < 2) {
2392 len += sprintf(mask_str + len, "\n");
2393 count = simple_read_from_buffer(ubuf, count, ppos, mask_str, NR_CPUS+1);
2396 mutex_unlock(&tracing_cpumask_update_lock);
2402 tracing_cpumask_write(struct file *filp, const char __user *ubuf,
2403 size_t count, loff_t *ppos)
2406 cpumask_var_t tracing_cpumask_new;
2408 if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
2411 err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
2415 mutex_lock(&tracing_cpumask_update_lock);
2417 local_irq_disable();
2418 arch_spin_lock(&ftrace_max_lock);
2419 for_each_tracing_cpu(cpu) {
2421 * Increase/decrease the disabled counter if we are
2422 * about to flip a bit in the cpumask:
2424 if (cpumask_test_cpu(cpu, tracing_cpumask) &&
2425 !cpumask_test_cpu(cpu, tracing_cpumask_new)) {
2426 atomic_inc(&global_trace.data[cpu]->disabled);
2428 if (!cpumask_test_cpu(cpu, tracing_cpumask) &&
2429 cpumask_test_cpu(cpu, tracing_cpumask_new)) {
2430 atomic_dec(&global_trace.data[cpu]->disabled);
2433 arch_spin_unlock(&ftrace_max_lock);
2436 cpumask_copy(tracing_cpumask, tracing_cpumask_new);
2438 mutex_unlock(&tracing_cpumask_update_lock);
2439 free_cpumask_var(tracing_cpumask_new);
2444 free_cpumask_var(tracing_cpumask_new);
2449 static const struct file_operations tracing_cpumask_fops = {
2450 .open = tracing_open_generic,
2451 .read = tracing_cpumask_read,
2452 .write = tracing_cpumask_write,
2453 .llseek = generic_file_llseek,
2456 static int tracing_trace_options_show(struct seq_file *m, void *v)
2458 struct tracer_opt *trace_opts;
2462 mutex_lock(&trace_types_lock);
2463 tracer_flags = current_trace->flags->val;
2464 trace_opts = current_trace->flags->opts;
2466 for (i = 0; trace_options[i]; i++) {
2467 if (trace_flags & (1 << i))
2468 seq_printf(m, "%s\n", trace_options[i]);
2470 seq_printf(m, "no%s\n", trace_options[i]);
2473 for (i = 0; trace_opts[i].name; i++) {
2474 if (tracer_flags & trace_opts[i].bit)
2475 seq_printf(m, "%s\n", trace_opts[i].name);
2477 seq_printf(m, "no%s\n", trace_opts[i].name);
2479 mutex_unlock(&trace_types_lock);
2484 static int __set_tracer_option(struct tracer *trace,
2485 struct tracer_flags *tracer_flags,
2486 struct tracer_opt *opts, int neg)
2490 ret = trace->set_flag(tracer_flags->val, opts->bit, !neg);
2495 tracer_flags->val &= ~opts->bit;
2497 tracer_flags->val |= opts->bit;
2501 /* Try to assign a tracer specific option */
2502 static int set_tracer_option(struct tracer *trace, char *cmp, int neg)
2504 struct tracer_flags *tracer_flags = trace->flags;
2505 struct tracer_opt *opts = NULL;
2508 for (i = 0; tracer_flags->opts[i].name; i++) {
2509 opts = &tracer_flags->opts[i];
2511 if (strcmp(cmp, opts->name) == 0)
2512 return __set_tracer_option(trace, trace->flags,
2519 static void set_tracer_flags(unsigned int mask, int enabled)
2521 /* do nothing if flag is already set */
2522 if (!!(trace_flags & mask) == !!enabled)
2526 trace_flags |= mask;
2528 trace_flags &= ~mask;
2530 if (mask == TRACE_ITER_RECORD_CMD)
2531 trace_event_enable_cmd_record(enabled);
2535 tracing_trace_options_write(struct file *filp, const char __user *ubuf,
2536 size_t cnt, loff_t *ppos)
2544 if (cnt >= sizeof(buf))
2547 if (copy_from_user(&buf, ubuf, cnt))
2551 cmp = strstrip(buf);
2553 if (strncmp(cmp, "no", 2) == 0) {
2558 for (i = 0; trace_options[i]; i++) {
2559 if (strcmp(cmp, trace_options[i]) == 0) {
2560 set_tracer_flags(1 << i, !neg);
2565 /* If no option could be set, test the specific tracer options */
2566 if (!trace_options[i]) {
2567 mutex_lock(&trace_types_lock);
2568 ret = set_tracer_option(current_trace, cmp, neg);
2569 mutex_unlock(&trace_types_lock);
2579 static int tracing_trace_options_open(struct inode *inode, struct file *file)
2581 if (tracing_disabled)
2583 return single_open(file, tracing_trace_options_show, NULL);
2586 static const struct file_operations tracing_iter_fops = {
2587 .open = tracing_trace_options_open,
2589 .llseek = seq_lseek,
2590 .release = single_release,
2591 .write = tracing_trace_options_write,
2594 static const char readme_msg[] =
2595 "tracing mini-HOWTO:\n\n"
2596 "# mount -t debugfs nodev /sys/kernel/debug\n\n"
2597 "# cat /sys/kernel/debug/tracing/available_tracers\n"
2598 "wakeup preemptirqsoff preemptoff irqsoff function sched_switch nop\n\n"
2599 "# cat /sys/kernel/debug/tracing/current_tracer\n"
2601 "# echo sched_switch > /sys/kernel/debug/tracing/current_tracer\n"
2602 "# cat /sys/kernel/debug/tracing/current_tracer\n"
2604 "# cat /sys/kernel/debug/tracing/trace_options\n"
2605 "noprint-parent nosym-offset nosym-addr noverbose\n"
2606 "# echo print-parent > /sys/kernel/debug/tracing/trace_options\n"
2607 "# echo 1 > /sys/kernel/debug/tracing/tracing_enabled\n"
2608 "# cat /sys/kernel/debug/tracing/trace > /tmp/trace.txt\n"
2609 "# echo 0 > /sys/kernel/debug/tracing/tracing_enabled\n"
2613 tracing_readme_read(struct file *filp, char __user *ubuf,
2614 size_t cnt, loff_t *ppos)
2616 return simple_read_from_buffer(ubuf, cnt, ppos,
2617 readme_msg, strlen(readme_msg));
2620 static const struct file_operations tracing_readme_fops = {
2621 .open = tracing_open_generic,
2622 .read = tracing_readme_read,
2623 .llseek = generic_file_llseek,
2627 tracing_saved_cmdlines_read(struct file *file, char __user *ubuf,
2628 size_t cnt, loff_t *ppos)
2637 file_buf = kmalloc(SAVED_CMDLINES*(16+TASK_COMM_LEN), GFP_KERNEL);
2641 buf_comm = kmalloc(TASK_COMM_LEN, GFP_KERNEL);
2649 for (i = 0; i < SAVED_CMDLINES; i++) {
2652 pid = map_cmdline_to_pid[i];
2653 if (pid == -1 || pid == NO_CMDLINE_MAP)
2656 trace_find_cmdline(pid, buf_comm);
2657 r = sprintf(buf, "%d %s\n", pid, buf_comm);
2662 len = simple_read_from_buffer(ubuf, cnt, ppos,
2671 static const struct file_operations tracing_saved_cmdlines_fops = {
2672 .open = tracing_open_generic,
2673 .read = tracing_saved_cmdlines_read,
2674 .llseek = generic_file_llseek,
2678 tracing_ctrl_read(struct file *filp, char __user *ubuf,
2679 size_t cnt, loff_t *ppos)
2684 r = sprintf(buf, "%u\n", tracer_enabled);
2685 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2689 tracing_ctrl_write(struct file *filp, const char __user *ubuf,
2690 size_t cnt, loff_t *ppos)
2692 struct trace_array *tr = filp->private_data;
2697 if (cnt >= sizeof(buf))
2700 if (copy_from_user(&buf, ubuf, cnt))
2705 ret = strict_strtoul(buf, 10, &val);
2711 mutex_lock(&trace_types_lock);
2712 if (tracer_enabled ^ val) {
2715 if (current_trace->start)
2716 current_trace->start(tr);
2721 if (current_trace->stop)
2722 current_trace->stop(tr);
2725 mutex_unlock(&trace_types_lock);
2733 tracing_set_trace_read(struct file *filp, char __user *ubuf,
2734 size_t cnt, loff_t *ppos)
2736 char buf[MAX_TRACER_SIZE+2];
2739 mutex_lock(&trace_types_lock);
2741 r = sprintf(buf, "%s\n", current_trace->name);
2743 r = sprintf(buf, "\n");
2744 mutex_unlock(&trace_types_lock);
2746 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2749 int tracer_init(struct tracer *t, struct trace_array *tr)
2751 tracing_reset_online_cpus(tr);
2755 static int tracing_resize_ring_buffer(unsigned long size)
2760 * If kernel or user changes the size of the ring buffer
2761 * we use the size that was given, and we can forget about
2762 * expanding it later.
2764 ring_buffer_expanded = 1;
2766 ret = ring_buffer_resize(global_trace.buffer, size);
2770 if (!current_trace->use_max_tr)
2773 ret = ring_buffer_resize(max_tr.buffer, size);
2777 r = ring_buffer_resize(global_trace.buffer,
2778 global_trace.entries);
2781 * AARGH! We are left with different
2782 * size max buffer!!!!
2783 * The max buffer is our "snapshot" buffer.
2784 * When a tracer needs a snapshot (one of the
2785 * latency tracers), it swaps the max buffer
2786 * with the saved snap shot. We succeeded to
2787 * update the size of the main buffer, but failed to
2788 * update the size of the max buffer. But when we tried
2789 * to reset the main buffer to the original size, we
2790 * failed there too. This is very unlikely to
2791 * happen, but if it does, warn and kill all
2795 tracing_disabled = 1;
2800 max_tr.entries = size;
2802 global_trace.entries = size;
2809 * tracing_update_buffers - used by tracing facility to expand ring buffers
2811 * To save on memory when the tracing is never used on a system with it
2812 * configured in. The ring buffers are set to a minimum size. But once
2813 * a user starts to use the tracing facility, then they need to grow
2814 * to their default size.
2816 * This function is to be called when a tracer is about to be used.
2818 int tracing_update_buffers(void)
2822 mutex_lock(&trace_types_lock);
2823 if (!ring_buffer_expanded)
2824 ret = tracing_resize_ring_buffer(trace_buf_size);
2825 mutex_unlock(&trace_types_lock);
2830 struct trace_option_dentry;
2832 static struct trace_option_dentry *
2833 create_trace_option_files(struct tracer *tracer);
2836 destroy_trace_option_files(struct trace_option_dentry *topts);
2838 static int tracing_set_tracer(const char *buf)
2840 static struct trace_option_dentry *topts;
2841 struct trace_array *tr = &global_trace;
2845 mutex_lock(&trace_types_lock);
2847 if (!ring_buffer_expanded) {
2848 ret = tracing_resize_ring_buffer(trace_buf_size);
2854 for (t = trace_types; t; t = t->next) {
2855 if (strcmp(t->name, buf) == 0)
2862 if (t == current_trace)
2865 trace_branch_disable();
2866 if (current_trace && current_trace->reset)
2867 current_trace->reset(tr);
2868 if (current_trace && current_trace->use_max_tr) {
2870 * We don't free the ring buffer. instead, resize it because
2871 * The max_tr ring buffer has some state (e.g. ring->clock) and
2872 * we want preserve it.
2874 ring_buffer_resize(max_tr.buffer, 1);
2877 destroy_trace_option_files(topts);
2881 topts = create_trace_option_files(current_trace);
2882 if (current_trace->use_max_tr) {
2883 ret = ring_buffer_resize(max_tr.buffer, global_trace.entries);
2886 max_tr.entries = global_trace.entries;
2890 ret = tracer_init(t, tr);
2895 trace_branch_enable(tr);
2897 mutex_unlock(&trace_types_lock);
2903 tracing_set_trace_write(struct file *filp, const char __user *ubuf,
2904 size_t cnt, loff_t *ppos)
2906 char buf[MAX_TRACER_SIZE+1];
2913 if (cnt > MAX_TRACER_SIZE)
2914 cnt = MAX_TRACER_SIZE;
2916 if (copy_from_user(&buf, ubuf, cnt))
2921 /* strip ending whitespace. */
2922 for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
2925 err = tracing_set_tracer(buf);
2935 tracing_max_lat_read(struct file *filp, char __user *ubuf,
2936 size_t cnt, loff_t *ppos)
2938 unsigned long *ptr = filp->private_data;
2942 r = snprintf(buf, sizeof(buf), "%ld\n",
2943 *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
2944 if (r > sizeof(buf))
2946 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2950 tracing_max_lat_write(struct file *filp, const char __user *ubuf,
2951 size_t cnt, loff_t *ppos)
2953 unsigned long *ptr = filp->private_data;
2958 if (cnt >= sizeof(buf))
2961 if (copy_from_user(&buf, ubuf, cnt))
2966 ret = strict_strtoul(buf, 10, &val);
2975 static int tracing_open_pipe(struct inode *inode, struct file *filp)
2977 long cpu_file = (long) inode->i_private;
2978 struct trace_iterator *iter;
2981 if (tracing_disabled)
2984 mutex_lock(&trace_types_lock);
2986 /* create a buffer to store the information to pass to userspace */
2987 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2994 * We make a copy of the current tracer to avoid concurrent
2995 * changes on it while we are reading.
2997 iter->trace = kmalloc(sizeof(*iter->trace), GFP_KERNEL);
3003 *iter->trace = *current_trace;
3005 if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
3010 /* trace pipe does not show start of buffer */
3011 cpumask_setall(iter->started);
3013 if (trace_flags & TRACE_ITER_LATENCY_FMT)
3014 iter->iter_flags |= TRACE_FILE_LAT_FMT;
3016 iter->cpu_file = cpu_file;
3017 iter->tr = &global_trace;
3018 mutex_init(&iter->mutex);
3019 filp->private_data = iter;
3021 if (iter->trace->pipe_open)
3022 iter->trace->pipe_open(iter);
3024 nonseekable_open(inode, filp);
3026 mutex_unlock(&trace_types_lock);
3032 mutex_unlock(&trace_types_lock);
3036 static int tracing_release_pipe(struct inode *inode, struct file *file)
3038 struct trace_iterator *iter = file->private_data;
3040 mutex_lock(&trace_types_lock);
3042 if (iter->trace->pipe_close)
3043 iter->trace->pipe_close(iter);
3045 mutex_unlock(&trace_types_lock);
3047 free_cpumask_var(iter->started);
3048 mutex_destroy(&iter->mutex);
3056 tracing_poll_pipe(struct file *filp, poll_table *poll_table)
3058 struct trace_iterator *iter = filp->private_data;
3060 if (trace_flags & TRACE_ITER_BLOCK) {
3062 * Always select as readable when in blocking mode
3064 return POLLIN | POLLRDNORM;
3066 if (!trace_empty(iter))
3067 return POLLIN | POLLRDNORM;
3068 poll_wait(filp, &trace_wait, poll_table);
3069 if (!trace_empty(iter))
3070 return POLLIN | POLLRDNORM;
3077 void default_wait_pipe(struct trace_iterator *iter)
3081 prepare_to_wait(&trace_wait, &wait, TASK_INTERRUPTIBLE);
3083 if (trace_empty(iter))
3086 finish_wait(&trace_wait, &wait);
3090 * This is a make-shift waitqueue.
3091 * A tracer might use this callback on some rare cases:
3093 * 1) the current tracer might hold the runqueue lock when it wakes up
3094 * a reader, hence a deadlock (sched, function, and function graph tracers)
3095 * 2) the function tracers, trace all functions, we don't want
3096 * the overhead of calling wake_up and friends
3097 * (and tracing them too)
3099 * Anyway, this is really very primitive wakeup.
3101 void poll_wait_pipe(struct trace_iterator *iter)
3103 set_current_state(TASK_INTERRUPTIBLE);
3104 /* sleep for 100 msecs, and try again. */
3105 schedule_timeout(HZ / 10);
3108 /* Must be called with trace_types_lock mutex held. */
3109 static int tracing_wait_pipe(struct file *filp)
3111 struct trace_iterator *iter = filp->private_data;
3113 while (trace_empty(iter)) {
3115 if ((filp->f_flags & O_NONBLOCK)) {
3119 mutex_unlock(&iter->mutex);
3121 iter->trace->wait_pipe(iter);
3123 mutex_lock(&iter->mutex);
3125 if (signal_pending(current))
3129 * We block until we read something and tracing is disabled.
3130 * We still block if tracing is disabled, but we have never
3131 * read anything. This allows a user to cat this file, and
3132 * then enable tracing. But after we have read something,
3133 * we give an EOF when tracing is again disabled.
3135 * iter->pos will be 0 if we haven't read anything.
3137 if (!tracer_enabled && iter->pos)
3148 tracing_read_pipe(struct file *filp, char __user *ubuf,
3149 size_t cnt, loff_t *ppos)
3151 struct trace_iterator *iter = filp->private_data;
3152 static struct tracer *old_tracer;
3155 /* return any leftover data */
3156 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
3160 trace_seq_init(&iter->seq);
3162 /* copy the tracer to avoid using a global lock all around */
3163 mutex_lock(&trace_types_lock);
3164 if (unlikely(old_tracer != current_trace && current_trace)) {
3165 old_tracer = current_trace;
3166 *iter->trace = *current_trace;
3168 mutex_unlock(&trace_types_lock);
3171 * Avoid more than one consumer on a single file descriptor
3172 * This is just a matter of traces coherency, the ring buffer itself
3175 mutex_lock(&iter->mutex);
3176 if (iter->trace->read) {
3177 sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
3183 sret = tracing_wait_pipe(filp);
3187 /* stop when tracing is finished */
3188 if (trace_empty(iter)) {
3193 if (cnt >= PAGE_SIZE)
3194 cnt = PAGE_SIZE - 1;
3196 /* reset all but tr, trace, and overruns */
3197 memset(&iter->seq, 0,
3198 sizeof(struct trace_iterator) -
3199 offsetof(struct trace_iterator, seq));
3202 trace_event_read_lock();
3203 trace_access_lock(iter->cpu_file);
3204 while (trace_find_next_entry_inc(iter) != NULL) {
3205 enum print_line_t ret;
3206 int len = iter->seq.len;
3208 ret = print_trace_line(iter);
3209 if (ret == TRACE_TYPE_PARTIAL_LINE) {
3210 /* don't print partial lines */
3211 iter->seq.len = len;
3214 if (ret != TRACE_TYPE_NO_CONSUME)
3215 trace_consume(iter);
3217 if (iter->seq.len >= cnt)
3220 trace_access_unlock(iter->cpu_file);
3221 trace_event_read_unlock();
3223 /* Now copy what we have to the user */
3224 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
3225 if (iter->seq.readpos >= iter->seq.len)
3226 trace_seq_init(&iter->seq);
3229 * If there was nothing to send to user, inspite of consuming trace
3230 * entries, go back to wait for more entries.
3236 mutex_unlock(&iter->mutex);
3241 static void tracing_pipe_buf_release(struct pipe_inode_info *pipe,
3242 struct pipe_buffer *buf)
3244 __free_page(buf->page);
3247 static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
3250 __free_page(spd->pages[idx]);
3253 static const struct pipe_buf_operations tracing_pipe_buf_ops = {
3255 .map = generic_pipe_buf_map,
3256 .unmap = generic_pipe_buf_unmap,
3257 .confirm = generic_pipe_buf_confirm,
3258 .release = tracing_pipe_buf_release,
3259 .steal = generic_pipe_buf_steal,
3260 .get = generic_pipe_buf_get,
3264 tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
3269 /* Seq buffer is page-sized, exactly what we need. */
3271 count = iter->seq.len;
3272 ret = print_trace_line(iter);
3273 count = iter->seq.len - count;
3276 iter->seq.len -= count;
3279 if (ret == TRACE_TYPE_PARTIAL_LINE) {
3280 iter->seq.len -= count;
3284 if (ret != TRACE_TYPE_NO_CONSUME)
3285 trace_consume(iter);
3287 if (!trace_find_next_entry_inc(iter)) {
3297 static ssize_t tracing_splice_read_pipe(struct file *filp,
3299 struct pipe_inode_info *pipe,
3303 struct page *pages_def[PIPE_DEF_BUFFERS];
3304 struct partial_page partial_def[PIPE_DEF_BUFFERS];
3305 struct trace_iterator *iter = filp->private_data;
3306 struct splice_pipe_desc spd = {
3308 .partial = partial_def,
3309 .nr_pages = 0, /* This gets updated below. */
3311 .ops = &tracing_pipe_buf_ops,
3312 .spd_release = tracing_spd_release_pipe,
3314 static struct tracer *old_tracer;
3319 if (splice_grow_spd(pipe, &spd))
3322 /* copy the tracer to avoid using a global lock all around */
3323 mutex_lock(&trace_types_lock);
3324 if (unlikely(old_tracer != current_trace && current_trace)) {
3325 old_tracer = current_trace;
3326 *iter->trace = *current_trace;
3328 mutex_unlock(&trace_types_lock);
3330 mutex_lock(&iter->mutex);
3332 if (iter->trace->splice_read) {
3333 ret = iter->trace->splice_read(iter, filp,
3334 ppos, pipe, len, flags);
3339 ret = tracing_wait_pipe(filp);
3343 if (!iter->ent && !trace_find_next_entry_inc(iter)) {
3348 trace_event_read_lock();
3349 trace_access_lock(iter->cpu_file);
3351 /* Fill as many pages as possible. */
3352 for (i = 0, rem = len; i < pipe->buffers && rem; i++) {
3353 spd.pages[i] = alloc_page(GFP_KERNEL);
3357 rem = tracing_fill_pipe_page(rem, iter);
3359 /* Copy the data into the page, so we can start over. */
3360 ret = trace_seq_to_buffer(&iter->seq,
3361 page_address(spd.pages[i]),
3364 __free_page(spd.pages[i]);
3367 spd.partial[i].offset = 0;
3368 spd.partial[i].len = iter->seq.len;
3370 trace_seq_init(&iter->seq);
3373 trace_access_unlock(iter->cpu_file);
3374 trace_event_read_unlock();
3375 mutex_unlock(&iter->mutex);
3379 ret = splice_to_pipe(pipe, &spd);
3381 splice_shrink_spd(pipe, &spd);
3385 mutex_unlock(&iter->mutex);
3390 tracing_entries_read(struct file *filp, char __user *ubuf,
3391 size_t cnt, loff_t *ppos)
3393 struct trace_array *tr = filp->private_data;
3397 mutex_lock(&trace_types_lock);
3398 if (!ring_buffer_expanded)
3399 r = sprintf(buf, "%lu (expanded: %lu)\n",
3401 trace_buf_size >> 10);
3403 r = sprintf(buf, "%lu\n", tr->entries >> 10);
3404 mutex_unlock(&trace_types_lock);
3406 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
3410 tracing_entries_write(struct file *filp, const char __user *ubuf,
3411 size_t cnt, loff_t *ppos)
3417 if (cnt >= sizeof(buf))
3420 if (copy_from_user(&buf, ubuf, cnt))
3425 ret = strict_strtoul(buf, 10, &val);
3429 /* must have at least 1 entry */
3433 mutex_lock(&trace_types_lock);
3437 /* disable all cpu buffers */
3438 for_each_tracing_cpu(cpu) {
3439 if (global_trace.data[cpu])
3440 atomic_inc(&global_trace.data[cpu]->disabled);
3441 if (max_tr.data[cpu])
3442 atomic_inc(&max_tr.data[cpu]->disabled);
3445 /* value is in KB */
3448 if (val != global_trace.entries) {
3449 ret = tracing_resize_ring_buffer(val);
3458 /* If check pages failed, return ENOMEM */
3459 if (tracing_disabled)
3462 for_each_tracing_cpu(cpu) {
3463 if (global_trace.data[cpu])
3464 atomic_dec(&global_trace.data[cpu]->disabled);
3465 if (max_tr.data[cpu])
3466 atomic_dec(&max_tr.data[cpu]->disabled);
3470 mutex_unlock(&trace_types_lock);
3475 static int mark_printk(const char *fmt, ...)
3479 va_start(args, fmt);
3480 ret = trace_vprintk(0, fmt, args);
3486 tracing_mark_write(struct file *filp, const char __user *ubuf,
3487 size_t cnt, loff_t *fpos)
3492 if (tracing_disabled)
3495 if (cnt > TRACE_BUF_SIZE)
3496 cnt = TRACE_BUF_SIZE;
3498 buf = kmalloc(cnt + 2, GFP_KERNEL);
3502 if (copy_from_user(buf, ubuf, cnt)) {
3506 if (buf[cnt-1] != '\n') {
3512 written = mark_printk("%s", buf);
3516 /* don't tell userspace we wrote more - it might confuse them */
3523 static int tracing_clock_show(struct seq_file *m, void *v)
3527 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++)
3529 "%s%s%s%s", i ? " " : "",
3530 i == trace_clock_id ? "[" : "", trace_clocks[i].name,
3531 i == trace_clock_id ? "]" : "");
3537 static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf,
3538 size_t cnt, loff_t *fpos)
3541 const char *clockstr;
3544 if (cnt >= sizeof(buf))
3547 if (copy_from_user(&buf, ubuf, cnt))
3552 clockstr = strstrip(buf);
3554 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) {
3555 if (strcmp(trace_clocks[i].name, clockstr) == 0)
3558 if (i == ARRAY_SIZE(trace_clocks))
3563 mutex_lock(&trace_types_lock);
3565 ring_buffer_set_clock(global_trace.buffer, trace_clocks[i].func);
3567 ring_buffer_set_clock(max_tr.buffer, trace_clocks[i].func);
3569 mutex_unlock(&trace_types_lock);
3576 static int tracing_clock_open(struct inode *inode, struct file *file)
3578 if (tracing_disabled)
3580 return single_open(file, tracing_clock_show, NULL);
3583 static const struct file_operations tracing_max_lat_fops = {
3584 .open = tracing_open_generic,
3585 .read = tracing_max_lat_read,
3586 .write = tracing_max_lat_write,
3587 .llseek = generic_file_llseek,
3590 static const struct file_operations tracing_ctrl_fops = {
3591 .open = tracing_open_generic,
3592 .read = tracing_ctrl_read,
3593 .write = tracing_ctrl_write,
3594 .llseek = generic_file_llseek,
3597 static const struct file_operations set_tracer_fops = {
3598 .open = tracing_open_generic,
3599 .read = tracing_set_trace_read,
3600 .write = tracing_set_trace_write,
3601 .llseek = generic_file_llseek,
3604 static const struct file_operations tracing_pipe_fops = {
3605 .open = tracing_open_pipe,
3606 .poll = tracing_poll_pipe,
3607 .read = tracing_read_pipe,
3608 .splice_read = tracing_splice_read_pipe,
3609 .release = tracing_release_pipe,
3610 .llseek = no_llseek,
3613 static const struct file_operations tracing_entries_fops = {
3614 .open = tracing_open_generic,
3615 .read = tracing_entries_read,
3616 .write = tracing_entries_write,
3617 .llseek = generic_file_llseek,
3620 static const struct file_operations tracing_mark_fops = {
3621 .open = tracing_open_generic,
3622 .write = tracing_mark_write,
3623 .llseek = generic_file_llseek,
3626 static const struct file_operations trace_clock_fops = {
3627 .open = tracing_clock_open,
3629 .llseek = seq_lseek,
3630 .release = single_release,
3631 .write = tracing_clock_write,
3634 struct ftrace_buffer_info {
3635 struct trace_array *tr;
3641 static int tracing_buffers_open(struct inode *inode, struct file *filp)
3643 int cpu = (int)(long)inode->i_private;
3644 struct ftrace_buffer_info *info;
3646 if (tracing_disabled)
3649 info = kzalloc(sizeof(*info), GFP_KERNEL);
3653 info->tr = &global_trace;
3656 /* Force reading ring buffer for first read */
3657 info->read = (unsigned int)-1;
3659 filp->private_data = info;
3661 return nonseekable_open(inode, filp);
3665 tracing_buffers_read(struct file *filp, char __user *ubuf,
3666 size_t count, loff_t *ppos)
3668 struct ftrace_buffer_info *info = filp->private_data;
3676 info->spare = ring_buffer_alloc_read_page(info->tr->buffer);
3680 /* Do we have previous read data to read? */
3681 if (info->read < PAGE_SIZE)
3686 trace_access_lock(info->cpu);
3687 ret = ring_buffer_read_page(info->tr->buffer,
3691 trace_access_unlock(info->cpu);
3696 size = PAGE_SIZE - info->read;
3700 ret = copy_to_user(ubuf, info->spare + info->read, size);
3711 static int tracing_buffers_release(struct inode *inode, struct file *file)
3713 struct ftrace_buffer_info *info = file->private_data;
3716 ring_buffer_free_read_page(info->tr->buffer, info->spare);
3723 struct ring_buffer *buffer;
3728 static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
3729 struct pipe_buffer *buf)
3731 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
3736 ring_buffer_free_read_page(ref->buffer, ref->page);
3741 static int buffer_pipe_buf_steal(struct pipe_inode_info *pipe,
3742 struct pipe_buffer *buf)
3747 static void buffer_pipe_buf_get(struct pipe_inode_info *pipe,
3748 struct pipe_buffer *buf)
3750 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
3755 /* Pipe buffer operations for a buffer. */
3756 static const struct pipe_buf_operations buffer_pipe_buf_ops = {
3758 .map = generic_pipe_buf_map,
3759 .unmap = generic_pipe_buf_unmap,
3760 .confirm = generic_pipe_buf_confirm,
3761 .release = buffer_pipe_buf_release,
3762 .steal = buffer_pipe_buf_steal,
3763 .get = buffer_pipe_buf_get,
3767 * Callback from splice_to_pipe(), if we need to release some pages
3768 * at the end of the spd in case we error'ed out in filling the pipe.
3770 static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
3772 struct buffer_ref *ref =
3773 (struct buffer_ref *)spd->partial[i].private;
3778 ring_buffer_free_read_page(ref->buffer, ref->page);
3780 spd->partial[i].private = 0;
3784 tracing_buffers_splice_read(struct file *file, loff_t *ppos,
3785 struct pipe_inode_info *pipe, size_t len,
3788 struct ftrace_buffer_info *info = file->private_data;
3789 struct partial_page partial_def[PIPE_DEF_BUFFERS];
3790 struct page *pages_def[PIPE_DEF_BUFFERS];
3791 struct splice_pipe_desc spd = {
3793 .partial = partial_def,
3795 .ops = &buffer_pipe_buf_ops,
3796 .spd_release = buffer_spd_release,
3798 struct buffer_ref *ref;
3799 int entries, size, i;
3802 if (splice_grow_spd(pipe, &spd))
3805 if (*ppos & (PAGE_SIZE - 1)) {
3806 WARN_ONCE(1, "Ftrace: previous read must page-align\n");
3811 if (len & (PAGE_SIZE - 1)) {
3812 WARN_ONCE(1, "Ftrace: splice_read should page-align\n");
3813 if (len < PAGE_SIZE) {
3820 trace_access_lock(info->cpu);
3821 entries = ring_buffer_entries_cpu(info->tr->buffer, info->cpu);
3823 for (i = 0; i < pipe->buffers && len && entries; i++, len -= PAGE_SIZE) {
3827 ref = kzalloc(sizeof(*ref), GFP_KERNEL);
3832 ref->buffer = info->tr->buffer;
3833 ref->page = ring_buffer_alloc_read_page(ref->buffer);
3839 r = ring_buffer_read_page(ref->buffer, &ref->page,
3842 ring_buffer_free_read_page(ref->buffer,
3849 * zero out any left over data, this is going to
3852 size = ring_buffer_page_len(ref->page);
3853 if (size < PAGE_SIZE)
3854 memset(ref->page + size, 0, PAGE_SIZE - size);
3856 page = virt_to_page(ref->page);
3858 spd.pages[i] = page;
3859 spd.partial[i].len = PAGE_SIZE;
3860 spd.partial[i].offset = 0;
3861 spd.partial[i].private = (unsigned long)ref;
3865 entries = ring_buffer_entries_cpu(info->tr->buffer, info->cpu);
3868 trace_access_unlock(info->cpu);
3871 /* did we read anything? */
3872 if (!spd.nr_pages) {
3873 if (flags & SPLICE_F_NONBLOCK)
3881 ret = splice_to_pipe(pipe, &spd);
3882 splice_shrink_spd(pipe, &spd);
3887 static const struct file_operations tracing_buffers_fops = {
3888 .open = tracing_buffers_open,
3889 .read = tracing_buffers_read,
3890 .release = tracing_buffers_release,
3891 .splice_read = tracing_buffers_splice_read,
3892 .llseek = no_llseek,
3896 tracing_stats_read(struct file *filp, char __user *ubuf,
3897 size_t count, loff_t *ppos)
3899 unsigned long cpu = (unsigned long)filp->private_data;
3900 struct trace_array *tr = &global_trace;
3901 struct trace_seq *s;
3904 s = kmalloc(sizeof(*s), GFP_KERNEL);
3910 cnt = ring_buffer_entries_cpu(tr->buffer, cpu);
3911 trace_seq_printf(s, "entries: %ld\n", cnt);
3913 cnt = ring_buffer_overrun_cpu(tr->buffer, cpu);
3914 trace_seq_printf(s, "overrun: %ld\n", cnt);
3916 cnt = ring_buffer_commit_overrun_cpu(tr->buffer, cpu);
3917 trace_seq_printf(s, "commit overrun: %ld\n", cnt);
3919 count = simple_read_from_buffer(ubuf, count, ppos, s->buffer, s->len);
3926 static const struct file_operations tracing_stats_fops = {
3927 .open = tracing_open_generic,
3928 .read = tracing_stats_read,
3929 .llseek = generic_file_llseek,
3932 #ifdef CONFIG_DYNAMIC_FTRACE
3934 int __weak ftrace_arch_read_dyn_info(char *buf, int size)
3940 tracing_read_dyn_info(struct file *filp, char __user *ubuf,
3941 size_t cnt, loff_t *ppos)
3943 static char ftrace_dyn_info_buffer[1024];
3944 static DEFINE_MUTEX(dyn_info_mutex);
3945 unsigned long *p = filp->private_data;
3946 char *buf = ftrace_dyn_info_buffer;
3947 int size = ARRAY_SIZE(ftrace_dyn_info_buffer);
3950 mutex_lock(&dyn_info_mutex);
3951 r = sprintf(buf, "%ld ", *p);
3953 r += ftrace_arch_read_dyn_info(buf+r, (size-1)-r);
3956 r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
3958 mutex_unlock(&dyn_info_mutex);
3963 static const struct file_operations tracing_dyn_info_fops = {
3964 .open = tracing_open_generic,
3965 .read = tracing_read_dyn_info,
3966 .llseek = generic_file_llseek,
3970 static struct dentry *d_tracer;
3972 struct dentry *tracing_init_dentry(void)
3979 if (!debugfs_initialized())
3982 d_tracer = debugfs_create_dir("tracing", NULL);
3984 if (!d_tracer && !once) {
3986 pr_warning("Could not create debugfs directory 'tracing'\n");
3993 static struct dentry *d_percpu;
3995 struct dentry *tracing_dentry_percpu(void)
3998 struct dentry *d_tracer;
4003 d_tracer = tracing_init_dentry();
4008 d_percpu = debugfs_create_dir("per_cpu", d_tracer);
4010 if (!d_percpu && !once) {
4012 pr_warning("Could not create debugfs directory 'per_cpu'\n");
4019 static void tracing_init_debugfs_percpu(long cpu)
4021 struct dentry *d_percpu = tracing_dentry_percpu();
4022 struct dentry *d_cpu;
4023 char cpu_dir[30]; /* 30 characters should be more than enough */
4025 snprintf(cpu_dir, 30, "cpu%ld", cpu);
4026 d_cpu = debugfs_create_dir(cpu_dir, d_percpu);
4028 pr_warning("Could not create debugfs '%s' entry\n", cpu_dir);
4032 /* per cpu trace_pipe */
4033 trace_create_file("trace_pipe", 0444, d_cpu,
4034 (void *) cpu, &tracing_pipe_fops);
4037 trace_create_file("trace", 0644, d_cpu,
4038 (void *) cpu, &tracing_fops);
4040 trace_create_file("trace_pipe_raw", 0444, d_cpu,
4041 (void *) cpu, &tracing_buffers_fops);
4043 trace_create_file("stats", 0444, d_cpu,
4044 (void *) cpu, &tracing_stats_fops);
4047 #ifdef CONFIG_FTRACE_SELFTEST
4048 /* Let selftest have access to static functions in this file */
4049 #include "trace_selftest.c"
4052 struct trace_option_dentry {
4053 struct tracer_opt *opt;
4054 struct tracer_flags *flags;
4055 struct dentry *entry;
4059 trace_options_read(struct file *filp, char __user *ubuf, size_t cnt,
4062 struct trace_option_dentry *topt = filp->private_data;
4065 if (topt->flags->val & topt->opt->bit)
4070 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
4074 trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt,
4077 struct trace_option_dentry *topt = filp->private_data;
4082 if (cnt >= sizeof(buf))
4085 if (copy_from_user(&buf, ubuf, cnt))
4090 ret = strict_strtoul(buf, 10, &val);
4094 if (val != 0 && val != 1)
4097 if (!!(topt->flags->val & topt->opt->bit) != val) {
4098 mutex_lock(&trace_types_lock);
4099 ret = __set_tracer_option(current_trace, topt->flags,
4101 mutex_unlock(&trace_types_lock);
4112 static const struct file_operations trace_options_fops = {
4113 .open = tracing_open_generic,
4114 .read = trace_options_read,
4115 .write = trace_options_write,
4116 .llseek = generic_file_llseek,
4120 trace_options_core_read(struct file *filp, char __user *ubuf, size_t cnt,
4123 long index = (long)filp->private_data;
4126 if (trace_flags & (1 << index))
4131 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
4135 trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
4138 long index = (long)filp->private_data;
4143 if (cnt >= sizeof(buf))
4146 if (copy_from_user(&buf, ubuf, cnt))
4151 ret = strict_strtoul(buf, 10, &val);
4155 if (val != 0 && val != 1)
4157 set_tracer_flags(1 << index, val);
4164 static const struct file_operations trace_options_core_fops = {
4165 .open = tracing_open_generic,
4166 .read = trace_options_core_read,
4167 .write = trace_options_core_write,
4168 .llseek = generic_file_llseek,
4171 struct dentry *trace_create_file(const char *name,
4173 struct dentry *parent,
4175 const struct file_operations *fops)
4179 ret = debugfs_create_file(name, mode, parent, data, fops);
4181 pr_warning("Could not create debugfs '%s' entry\n", name);
4187 static struct dentry *trace_options_init_dentry(void)
4189 struct dentry *d_tracer;
4190 static struct dentry *t_options;
4195 d_tracer = tracing_init_dentry();
4199 t_options = debugfs_create_dir("options", d_tracer);
4201 pr_warning("Could not create debugfs directory 'options'\n");
4209 create_trace_option_file(struct trace_option_dentry *topt,
4210 struct tracer_flags *flags,
4211 struct tracer_opt *opt)
4213 struct dentry *t_options;
4215 t_options = trace_options_init_dentry();
4219 topt->flags = flags;
4222 topt->entry = trace_create_file(opt->name, 0644, t_options, topt,
4223 &trace_options_fops);
4227 static struct trace_option_dentry *
4228 create_trace_option_files(struct tracer *tracer)
4230 struct trace_option_dentry *topts;
4231 struct tracer_flags *flags;
4232 struct tracer_opt *opts;
4238 flags = tracer->flags;
4240 if (!flags || !flags->opts)
4245 for (cnt = 0; opts[cnt].name; cnt++)
4248 topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL);
4252 for (cnt = 0; opts[cnt].name; cnt++)
4253 create_trace_option_file(&topts[cnt], flags,
4260 destroy_trace_option_files(struct trace_option_dentry *topts)
4267 for (cnt = 0; topts[cnt].opt; cnt++) {
4268 if (topts[cnt].entry)
4269 debugfs_remove(topts[cnt].entry);
4275 static struct dentry *
4276 create_trace_option_core_file(const char *option, long index)
4278 struct dentry *t_options;
4280 t_options = trace_options_init_dentry();
4284 return trace_create_file(option, 0644, t_options, (void *)index,
4285 &trace_options_core_fops);
4288 static __init void create_trace_options_dir(void)
4290 struct dentry *t_options;
4293 t_options = trace_options_init_dentry();
4297 for (i = 0; trace_options[i]; i++)
4298 create_trace_option_core_file(trace_options[i], i);
4301 static __init int tracer_init_debugfs(void)
4303 struct dentry *d_tracer;
4306 trace_access_lock_init();
4308 d_tracer = tracing_init_dentry();
4310 trace_create_file("tracing_enabled", 0644, d_tracer,
4311 &global_trace, &tracing_ctrl_fops);
4313 trace_create_file("trace_options", 0644, d_tracer,
4314 NULL, &tracing_iter_fops);
4316 trace_create_file("tracing_cpumask", 0644, d_tracer,
4317 NULL, &tracing_cpumask_fops);
4319 trace_create_file("trace", 0644, d_tracer,
4320 (void *) TRACE_PIPE_ALL_CPU, &tracing_fops);
4322 trace_create_file("available_tracers", 0444, d_tracer,
4323 &global_trace, &show_traces_fops);
4325 trace_create_file("current_tracer", 0644, d_tracer,
4326 &global_trace, &set_tracer_fops);
4328 #ifdef CONFIG_TRACER_MAX_TRACE
4329 trace_create_file("tracing_max_latency", 0644, d_tracer,
4330 &tracing_max_latency, &tracing_max_lat_fops);
4333 trace_create_file("tracing_thresh", 0644, d_tracer,
4334 &tracing_thresh, &tracing_max_lat_fops);
4336 trace_create_file("README", 0444, d_tracer,
4337 NULL, &tracing_readme_fops);
4339 trace_create_file("trace_pipe", 0444, d_tracer,
4340 (void *) TRACE_PIPE_ALL_CPU, &tracing_pipe_fops);
4342 trace_create_file("buffer_size_kb", 0644, d_tracer,
4343 &global_trace, &tracing_entries_fops);
4345 trace_create_file("trace_marker", 0220, d_tracer,
4346 NULL, &tracing_mark_fops);
4348 trace_create_file("saved_cmdlines", 0444, d_tracer,
4349 NULL, &tracing_saved_cmdlines_fops);
4351 trace_create_file("trace_clock", 0644, d_tracer, NULL,
4354 #ifdef CONFIG_DYNAMIC_FTRACE
4355 trace_create_file("dyn_ftrace_total_info", 0444, d_tracer,
4356 &ftrace_update_tot_cnt, &tracing_dyn_info_fops);
4359 create_trace_options_dir();
4361 for_each_tracing_cpu(cpu)
4362 tracing_init_debugfs_percpu(cpu);
4367 static int trace_panic_handler(struct notifier_block *this,
4368 unsigned long event, void *unused)
4370 if (ftrace_dump_on_oops)
4371 ftrace_dump(ftrace_dump_on_oops);
4375 static struct notifier_block trace_panic_notifier = {
4376 .notifier_call = trace_panic_handler,
4378 .priority = 150 /* priority: INT_MAX >= x >= 0 */
4381 static int trace_die_handler(struct notifier_block *self,
4387 if (ftrace_dump_on_oops)
4388 ftrace_dump(ftrace_dump_on_oops);
4396 static struct notifier_block trace_die_notifier = {
4397 .notifier_call = trace_die_handler,
4402 * printk is set to max of 1024, we really don't need it that big.
4403 * Nothing should be printing 1000 characters anyway.
4405 #define TRACE_MAX_PRINT 1000
4408 * Define here KERN_TRACE so that we have one place to modify
4409 * it if we decide to change what log level the ftrace dump
4412 #define KERN_TRACE KERN_EMERG
4415 trace_printk_seq(struct trace_seq *s)
4417 /* Probably should print a warning here. */
4421 /* should be zero ended, but we are paranoid. */
4422 s->buffer[s->len] = 0;
4424 printk(KERN_TRACE "%s", s->buffer);
4429 void trace_init_global_iter(struct trace_iterator *iter)
4431 iter->tr = &global_trace;
4432 iter->trace = current_trace;
4433 iter->cpu_file = TRACE_PIPE_ALL_CPU;
4437 __ftrace_dump(bool disable_tracing, enum ftrace_dump_mode oops_dump_mode)
4439 static arch_spinlock_t ftrace_dump_lock =
4440 (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
4441 /* use static because iter can be a bit big for the stack */
4442 static struct trace_iterator iter;
4443 unsigned int old_userobj;
4444 static int dump_ran;
4445 unsigned long flags;
4449 local_irq_save(flags);
4450 arch_spin_lock(&ftrace_dump_lock);
4458 if (disable_tracing)
4461 trace_init_global_iter(&iter);
4463 for_each_tracing_cpu(cpu) {
4464 atomic_inc(&iter.tr->data[cpu]->disabled);
4467 old_userobj = trace_flags & TRACE_ITER_SYM_USEROBJ;
4469 /* don't look at user memory in panic mode */
4470 trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
4472 /* Simulate the iterator */
4473 iter.tr = &global_trace;
4474 iter.trace = current_trace;
4476 switch (oops_dump_mode) {
4478 iter.cpu_file = TRACE_PIPE_ALL_CPU;
4481 iter.cpu_file = raw_smp_processor_id();
4486 printk(KERN_TRACE "Bad dumping mode, switching to all CPUs dump\n");
4487 iter.cpu_file = TRACE_PIPE_ALL_CPU;
4490 printk(KERN_TRACE "Dumping ftrace buffer:\n");
4493 * We need to stop all tracing on all CPUS to read the
4494 * the next buffer. This is a bit expensive, but is
4495 * not done often. We fill all what we can read,
4496 * and then release the locks again.
4499 while (!trace_empty(&iter)) {
4502 printk(KERN_TRACE "---------------------------------\n");
4506 /* reset all but tr, trace, and overruns */
4507 memset(&iter.seq, 0,
4508 sizeof(struct trace_iterator) -
4509 offsetof(struct trace_iterator, seq));
4510 iter.iter_flags |= TRACE_FILE_LAT_FMT;
4513 if (trace_find_next_entry_inc(&iter) != NULL) {
4516 ret = print_trace_line(&iter);
4517 if (ret != TRACE_TYPE_NO_CONSUME)
4518 trace_consume(&iter);
4521 trace_printk_seq(&iter.seq);
4525 printk(KERN_TRACE " (ftrace buffer empty)\n");
4527 printk(KERN_TRACE "---------------------------------\n");
4530 /* Re-enable tracing if requested */
4531 if (!disable_tracing) {
4532 trace_flags |= old_userobj;
4534 for_each_tracing_cpu(cpu) {
4535 atomic_dec(&iter.tr->data[cpu]->disabled);
4541 arch_spin_unlock(&ftrace_dump_lock);
4542 local_irq_restore(flags);
4545 /* By default: disable tracing after the dump */
4546 void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
4548 __ftrace_dump(true, oops_dump_mode);
4551 __init static int tracer_alloc_buffers(void)
4557 if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
4560 if (!alloc_cpumask_var(&tracing_cpumask, GFP_KERNEL))
4561 goto out_free_buffer_mask;
4563 /* To save memory, keep the ring buffer size to its minimum */
4564 if (ring_buffer_expanded)
4565 ring_buf_size = trace_buf_size;
4569 cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
4570 cpumask_copy(tracing_cpumask, cpu_all_mask);
4572 /* TODO: make the number of buffers hot pluggable with CPUS */
4573 global_trace.buffer = ring_buffer_alloc(ring_buf_size,
4574 TRACE_BUFFER_FLAGS);
4575 if (!global_trace.buffer) {
4576 printk(KERN_ERR "tracer: failed to allocate ring buffer!\n");
4578 goto out_free_cpumask;
4580 global_trace.entries = ring_buffer_size(global_trace.buffer);
4583 #ifdef CONFIG_TRACER_MAX_TRACE
4584 max_tr.buffer = ring_buffer_alloc(1, TRACE_BUFFER_FLAGS);
4585 if (!max_tr.buffer) {
4586 printk(KERN_ERR "tracer: failed to allocate max ring buffer!\n");
4588 ring_buffer_free(global_trace.buffer);
4589 goto out_free_cpumask;
4594 /* Allocate the first page for all buffers */
4595 for_each_tracing_cpu(i) {
4596 global_trace.data[i] = &per_cpu(global_trace_cpu, i);
4597 max_tr.data[i] = &per_cpu(max_tr_data, i);
4600 trace_init_cmdlines();
4602 register_tracer(&nop_trace);
4603 current_trace = &nop_trace;
4604 /* All seems OK, enable tracing */
4605 tracing_disabled = 0;
4607 atomic_notifier_chain_register(&panic_notifier_list,
4608 &trace_panic_notifier);
4610 register_die_notifier(&trace_die_notifier);
4615 free_cpumask_var(tracing_cpumask);
4616 out_free_buffer_mask:
4617 free_cpumask_var(tracing_buffer_mask);
4622 __init static int clear_boot_tracer(void)
4625 * The default tracer at boot buffer is an init section.
4626 * This function is called in lateinit. If we did not
4627 * find the boot tracer, then clear it out, to prevent
4628 * later registration from accessing the buffer that is
4629 * about to be freed.
4631 if (!default_bootup_tracer)
4634 printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n",
4635 default_bootup_tracer);
4636 default_bootup_tracer = NULL;
4641 early_initcall(tracer_alloc_buffers);
4642 fs_initcall(tracer_init_debugfs);
4643 late_initcall(clear_boot_tracer);