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 <linux/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/ctype.h>
34 #include <linux/init.h>
35 #include <linux/poll.h>
36 #include <linux/gfp.h>
40 #include "trace_output.h"
42 #define TRACE_BUFFER_FLAGS (RB_FL_OVERWRITE)
44 unsigned long __read_mostly tracing_max_latency;
45 unsigned long __read_mostly tracing_thresh;
48 * On boot up, the ring buffer is set to the minimum size, so that
49 * we do not waste memory on systems that are not using tracing.
51 static int ring_buffer_expanded;
54 * We need to change this state when a selftest is running.
55 * A selftest will lurk into the ring-buffer to count the
56 * entries inserted during the selftest although some concurrent
57 * insertions into the ring-buffer such as trace_printk could occurred
58 * at the same time, giving false positive or negative results.
60 static bool __read_mostly tracing_selftest_running;
63 * If a tracer is running, we do not want to run SELFTEST.
65 static bool __read_mostly tracing_selftest_disabled;
67 /* For tracers that don't implement custom flags */
68 static struct tracer_opt dummy_tracer_opt[] = {
72 static struct tracer_flags dummy_tracer_flags = {
74 .opts = dummy_tracer_opt
77 static int dummy_set_flag(u32 old_flags, u32 bit, int set)
83 * Kill all tracing for good (never come back).
84 * It is initialized to 1 but will turn to zero if the initialization
85 * of the tracer is successful. But that is the only place that sets
88 static int tracing_disabled = 1;
90 static DEFINE_PER_CPU(local_t, ftrace_cpu_disabled);
92 static inline void ftrace_disable_cpu(void)
95 local_inc(&__get_cpu_var(ftrace_cpu_disabled));
98 static inline void ftrace_enable_cpu(void)
100 local_dec(&__get_cpu_var(ftrace_cpu_disabled));
104 static cpumask_var_t __read_mostly tracing_buffer_mask;
106 /* Define which cpu buffers are currently read in trace_pipe */
107 static cpumask_var_t tracing_reader_cpumask;
109 #define for_each_tracing_cpu(cpu) \
110 for_each_cpu(cpu, tracing_buffer_mask)
113 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
115 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
116 * is set, then ftrace_dump is called. This will output the contents
117 * of the ftrace buffers to the console. This is very useful for
118 * capturing traces that lead to crashes and outputing it to a
121 * It is default off, but you can enable it with either specifying
122 * "ftrace_dump_on_oops" in the kernel command line, or setting
123 * /proc/sys/kernel/ftrace_dump_on_oops to true.
125 int ftrace_dump_on_oops;
127 static int tracing_set_tracer(const char *buf);
129 #define BOOTUP_TRACER_SIZE 100
130 static char bootup_tracer_buf[BOOTUP_TRACER_SIZE] __initdata;
131 static char *default_bootup_tracer;
133 static int __init set_ftrace(char *str)
135 strncpy(bootup_tracer_buf, str, BOOTUP_TRACER_SIZE);
136 default_bootup_tracer = bootup_tracer_buf;
137 /* We are using ftrace early, expand it */
138 ring_buffer_expanded = 1;
141 __setup("ftrace=", set_ftrace);
143 static int __init set_ftrace_dump_on_oops(char *str)
145 ftrace_dump_on_oops = 1;
148 __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
151 ns2usecs(cycle_t nsec)
159 * The global_trace is the descriptor that holds the tracing
160 * buffers for the live tracing. For each CPU, it contains
161 * a link list of pages that will store trace entries. The
162 * page descriptor of the pages in the memory is used to hold
163 * the link list by linking the lru item in the page descriptor
164 * to each of the pages in the buffer per CPU.
166 * For each active CPU there is a data field that holds the
167 * pages for the buffer for that CPU. Each CPU has the same number
168 * of pages allocated for its buffer.
170 static struct trace_array global_trace;
172 static DEFINE_PER_CPU(struct trace_array_cpu, global_trace_cpu);
174 cycle_t ftrace_now(int cpu)
178 /* Early boot up does not have a buffer yet */
179 if (!global_trace.buffer)
180 return trace_clock_local();
182 ts = ring_buffer_time_stamp(global_trace.buffer, cpu);
183 ring_buffer_normalize_time_stamp(global_trace.buffer, cpu, &ts);
189 * The max_tr is used to snapshot the global_trace when a maximum
190 * latency is reached. Some tracers will use this to store a maximum
191 * trace while it continues examining live traces.
193 * The buffers for the max_tr are set up the same as the global_trace.
194 * When a snapshot is taken, the link list of the max_tr is swapped
195 * with the link list of the global_trace and the buffers are reset for
196 * the global_trace so the tracing can continue.
198 static struct trace_array max_tr;
200 static DEFINE_PER_CPU(struct trace_array_cpu, max_data);
202 /* tracer_enabled is used to toggle activation of a tracer */
203 static int tracer_enabled = 1;
206 * tracing_is_enabled - return tracer_enabled status
208 * This function is used by other tracers to know the status
209 * of the tracer_enabled flag. Tracers may use this function
210 * to know if it should enable their features when starting
211 * up. See irqsoff tracer for an example (start_irqsoff_tracer).
213 int tracing_is_enabled(void)
215 return tracer_enabled;
219 * trace_buf_size is the size in bytes that is allocated
220 * for a buffer. Note, the number of bytes is always rounded
223 * This number is purposely set to a low number of 16384.
224 * If the dump on oops happens, it will be much appreciated
225 * to not have to wait for all that output. Anyway this can be
226 * boot time and run time configurable.
228 #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
230 static unsigned long trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
232 /* trace_types holds a link list of available tracers. */
233 static struct tracer *trace_types __read_mostly;
235 /* current_trace points to the tracer that is currently active */
236 static struct tracer *current_trace __read_mostly;
239 * max_tracer_type_len is used to simplify the allocating of
240 * buffers to read userspace tracer names. We keep track of
241 * the longest tracer name registered.
243 static int max_tracer_type_len;
246 * trace_types_lock is used to protect the trace_types list.
247 * This lock is also used to keep user access serialized.
248 * Accesses from userspace will grab this lock while userspace
249 * activities happen inside the kernel.
251 static DEFINE_MUTEX(trace_types_lock);
253 /* trace_wait is a waitqueue for tasks blocked on trace_poll */
254 static DECLARE_WAIT_QUEUE_HEAD(trace_wait);
256 /* trace_flags holds trace_options default values */
257 unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK |
258 TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO;
261 * trace_wake_up - wake up tasks waiting for trace input
263 * Simply wakes up any task that is blocked on the trace_wait
264 * queue. These is used with trace_poll for tasks polling the trace.
266 void trace_wake_up(void)
269 * The runqueue_is_locked() can fail, but this is the best we
272 if (!(trace_flags & TRACE_ITER_BLOCK) && !runqueue_is_locked())
273 wake_up(&trace_wait);
276 static int __init set_buf_size(char *str)
278 unsigned long buf_size;
283 ret = strict_strtoul(str, 0, &buf_size);
284 /* nr_entries can not be zero */
285 if (ret < 0 || buf_size == 0)
287 trace_buf_size = buf_size;
290 __setup("trace_buf_size=", set_buf_size);
292 unsigned long nsecs_to_usecs(unsigned long nsecs)
297 /* These must match the bit postions in trace_iterator_flags */
298 static const char *trace_options[] = {
323 * ftrace_max_lock is used to protect the swapping of buffers
324 * when taking a max snapshot. The buffers themselves are
325 * protected by per_cpu spinlocks. But the action of the swap
326 * needs its own lock.
328 * This is defined as a raw_spinlock_t in order to help
329 * with performance when lockdep debugging is enabled.
331 static raw_spinlock_t ftrace_max_lock =
332 (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
335 * Copy the new maximum trace into the separate maximum-trace
336 * structure. (this way the maximum trace is permanently saved,
337 * for later retrieval via /debugfs/tracing/latency_trace)
340 __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
342 struct trace_array_cpu *data = tr->data[cpu];
345 max_tr.time_start = data->preempt_timestamp;
347 data = max_tr.data[cpu];
348 data->saved_latency = tracing_max_latency;
350 memcpy(data->comm, tsk->comm, TASK_COMM_LEN);
351 data->pid = tsk->pid;
352 data->uid = task_uid(tsk);
353 data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
354 data->policy = tsk->policy;
355 data->rt_priority = tsk->rt_priority;
357 /* record this tasks comm */
358 tracing_record_cmdline(tsk);
361 ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
369 if (s->len <= s->readpos)
372 len = s->len - s->readpos;
375 ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
385 ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
390 if (s->len <= s->readpos)
393 len = s->len - s->readpos;
396 ret = memcpy(buf, s->buffer + s->readpos, cnt);
405 trace_print_seq(struct seq_file *m, struct trace_seq *s)
407 int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len;
410 seq_puts(m, s->buffer);
416 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
418 * @tsk: the task with the latency
419 * @cpu: The cpu that initiated the trace.
421 * Flip the buffers between the @tr and the max_tr and record information
422 * about which task was the cause of this latency.
425 update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
427 struct ring_buffer *buf = tr->buffer;
429 WARN_ON_ONCE(!irqs_disabled());
430 __raw_spin_lock(&ftrace_max_lock);
432 tr->buffer = max_tr.buffer;
435 ftrace_disable_cpu();
436 ring_buffer_reset(tr->buffer);
439 __update_max_tr(tr, tsk, cpu);
440 __raw_spin_unlock(&ftrace_max_lock);
444 * update_max_tr_single - only copy one trace over, and reset the rest
446 * @tsk - task with the latency
447 * @cpu - the cpu of the buffer to copy.
449 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
452 update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
456 WARN_ON_ONCE(!irqs_disabled());
457 __raw_spin_lock(&ftrace_max_lock);
459 ftrace_disable_cpu();
461 ring_buffer_reset(max_tr.buffer);
462 ret = ring_buffer_swap_cpu(max_tr.buffer, tr->buffer, cpu);
466 WARN_ON_ONCE(ret && ret != -EAGAIN);
468 __update_max_tr(tr, tsk, cpu);
469 __raw_spin_unlock(&ftrace_max_lock);
473 * register_tracer - register a tracer with the ftrace system.
474 * @type - the plugin for the tracer
476 * Register a new plugin tracer.
478 int register_tracer(struct tracer *type)
479 __releases(kernel_lock)
480 __acquires(kernel_lock)
487 pr_info("Tracer must have a name\n");
492 * When this gets called we hold the BKL which means that
493 * preemption is disabled. Various trace selftests however
494 * need to disable and enable preemption for successful tests.
495 * So we drop the BKL here and grab it after the tests again.
498 mutex_lock(&trace_types_lock);
500 tracing_selftest_running = true;
502 for (t = trace_types; t; t = t->next) {
503 if (strcmp(type->name, t->name) == 0) {
505 pr_info("Trace %s already registered\n",
513 type->set_flag = &dummy_set_flag;
515 type->flags = &dummy_tracer_flags;
517 if (!type->flags->opts)
518 type->flags->opts = dummy_tracer_opt;
519 if (!type->wait_pipe)
520 type->wait_pipe = default_wait_pipe;
523 #ifdef CONFIG_FTRACE_STARTUP_TEST
524 if (type->selftest && !tracing_selftest_disabled) {
525 struct tracer *saved_tracer = current_trace;
526 struct trace_array *tr = &global_trace;
530 * Run a selftest on this tracer.
531 * Here we reset the trace buffer, and set the current
532 * tracer to be this tracer. The tracer can then run some
533 * internal tracing to verify that everything is in order.
534 * If we fail, we do not register this tracer.
536 for_each_tracing_cpu(i)
537 tracing_reset(tr, i);
539 current_trace = type;
540 /* the test is responsible for initializing and enabling */
541 pr_info("Testing tracer %s: ", type->name);
542 ret = type->selftest(type, tr);
543 /* the test is responsible for resetting too */
544 current_trace = saved_tracer;
546 printk(KERN_CONT "FAILED!\n");
549 /* Only reset on passing, to avoid touching corrupted buffers */
550 for_each_tracing_cpu(i)
551 tracing_reset(tr, i);
553 printk(KERN_CONT "PASSED\n");
557 type->next = trace_types;
559 len = strlen(type->name);
560 if (len > max_tracer_type_len)
561 max_tracer_type_len = len;
564 tracing_selftest_running = false;
565 mutex_unlock(&trace_types_lock);
567 if (ret || !default_bootup_tracer)
570 if (strncmp(default_bootup_tracer, type->name, BOOTUP_TRACER_SIZE))
573 printk(KERN_INFO "Starting tracer '%s'\n", type->name);
574 /* Do we want this tracer to start on bootup? */
575 tracing_set_tracer(type->name);
576 default_bootup_tracer = NULL;
577 /* disable other selftests, since this will break it. */
578 tracing_selftest_disabled = 1;
579 #ifdef CONFIG_FTRACE_STARTUP_TEST
580 printk(KERN_INFO "Disabling FTRACE selftests due to running tracer '%s'\n",
589 void unregister_tracer(struct tracer *type)
594 mutex_lock(&trace_types_lock);
595 for (t = &trace_types; *t; t = &(*t)->next) {
599 pr_info("Trace %s not registered\n", type->name);
605 if (type == current_trace && tracer_enabled) {
608 if (current_trace->stop)
609 current_trace->stop(&global_trace);
610 current_trace = &nop_trace;
613 if (strlen(type->name) != max_tracer_type_len)
616 max_tracer_type_len = 0;
617 for (t = &trace_types; *t; t = &(*t)->next) {
618 len = strlen((*t)->name);
619 if (len > max_tracer_type_len)
620 max_tracer_type_len = len;
623 mutex_unlock(&trace_types_lock);
626 void tracing_reset(struct trace_array *tr, int cpu)
628 ftrace_disable_cpu();
629 ring_buffer_reset_cpu(tr->buffer, cpu);
633 void tracing_reset_online_cpus(struct trace_array *tr)
637 tr->time_start = ftrace_now(tr->cpu);
639 for_each_online_cpu(cpu)
640 tracing_reset(tr, cpu);
643 #define SAVED_CMDLINES 128
644 static unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
645 static unsigned map_cmdline_to_pid[SAVED_CMDLINES];
646 static char saved_cmdlines[SAVED_CMDLINES][TASK_COMM_LEN];
647 static int cmdline_idx;
648 static raw_spinlock_t trace_cmdline_lock = __RAW_SPIN_LOCK_UNLOCKED;
650 /* temporary disable recording */
651 static atomic_t trace_record_cmdline_disabled __read_mostly;
653 static void trace_init_cmdlines(void)
655 memset(&map_pid_to_cmdline, -1, sizeof(map_pid_to_cmdline));
656 memset(&map_cmdline_to_pid, -1, sizeof(map_cmdline_to_pid));
660 static int trace_stop_count;
661 static DEFINE_SPINLOCK(tracing_start_lock);
664 * ftrace_off_permanent - disable all ftrace code permanently
666 * This should only be called when a serious anomally has
667 * been detected. This will turn off the function tracing,
668 * ring buffers, and other tracing utilites. It takes no
669 * locks and can be called from any context.
671 void ftrace_off_permanent(void)
673 tracing_disabled = 1;
675 tracing_off_permanent();
679 * tracing_start - quick start of the tracer
681 * If tracing is enabled but was stopped by tracing_stop,
682 * this will start the tracer back up.
684 void tracing_start(void)
686 struct ring_buffer *buffer;
689 if (tracing_disabled)
692 spin_lock_irqsave(&tracing_start_lock, flags);
693 if (--trace_stop_count) {
694 if (trace_stop_count < 0) {
695 /* Someone screwed up their debugging */
697 trace_stop_count = 0;
703 buffer = global_trace.buffer;
705 ring_buffer_record_enable(buffer);
707 buffer = max_tr.buffer;
709 ring_buffer_record_enable(buffer);
713 spin_unlock_irqrestore(&tracing_start_lock, flags);
717 * tracing_stop - quick stop of the tracer
719 * Light weight way to stop tracing. Use in conjunction with
722 void tracing_stop(void)
724 struct ring_buffer *buffer;
728 spin_lock_irqsave(&tracing_start_lock, flags);
729 if (trace_stop_count++)
732 buffer = global_trace.buffer;
734 ring_buffer_record_disable(buffer);
736 buffer = max_tr.buffer;
738 ring_buffer_record_disable(buffer);
741 spin_unlock_irqrestore(&tracing_start_lock, flags);
744 void trace_stop_cmdline_recording(void);
746 static void trace_save_cmdline(struct task_struct *tsk)
751 if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT))
755 * It's not the end of the world if we don't get
756 * the lock, but we also don't want to spin
757 * nor do we want to disable interrupts,
758 * so if we miss here, then better luck next time.
760 if (!__raw_spin_trylock(&trace_cmdline_lock))
763 idx = map_pid_to_cmdline[tsk->pid];
764 if (idx >= SAVED_CMDLINES) {
765 idx = (cmdline_idx + 1) % SAVED_CMDLINES;
767 map = map_cmdline_to_pid[idx];
768 if (map <= PID_MAX_DEFAULT)
769 map_pid_to_cmdline[map] = (unsigned)-1;
771 map_pid_to_cmdline[tsk->pid] = idx;
776 memcpy(&saved_cmdlines[idx], tsk->comm, TASK_COMM_LEN);
778 __raw_spin_unlock(&trace_cmdline_lock);
781 void trace_find_cmdline(int pid, char comm[])
786 strcpy(comm, "<idle>");
790 if (pid > PID_MAX_DEFAULT) {
791 strcpy(comm, "<...>");
795 __raw_spin_lock(&trace_cmdline_lock);
796 map = map_pid_to_cmdline[pid];
797 if (map >= SAVED_CMDLINES)
800 strcpy(comm, saved_cmdlines[map]);
803 __raw_spin_unlock(&trace_cmdline_lock);
806 void tracing_record_cmdline(struct task_struct *tsk)
808 if (atomic_read(&trace_record_cmdline_disabled) || !tracing_is_on())
811 trace_save_cmdline(tsk);
815 tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
818 struct task_struct *tsk = current;
820 entry->preempt_count = pc & 0xff;
821 entry->pid = (tsk) ? tsk->pid : 0;
822 entry->tgid = (tsk) ? tsk->tgid : 0;
824 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
825 (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
827 TRACE_FLAG_IRQS_NOSUPPORT |
829 ((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
830 ((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
831 (need_resched() ? TRACE_FLAG_NEED_RESCHED : 0);
834 struct ring_buffer_event *trace_buffer_lock_reserve(struct trace_array *tr,
837 unsigned long flags, int pc)
839 struct ring_buffer_event *event;
841 event = ring_buffer_lock_reserve(tr->buffer, len);
843 struct trace_entry *ent = ring_buffer_event_data(event);
845 tracing_generic_entry_update(ent, flags, pc);
851 static void ftrace_trace_stack(struct trace_array *tr,
852 unsigned long flags, int skip, int pc);
853 static void ftrace_trace_userstack(struct trace_array *tr,
854 unsigned long flags, int pc);
856 void trace_buffer_unlock_commit(struct trace_array *tr,
857 struct ring_buffer_event *event,
858 unsigned long flags, int pc)
860 ring_buffer_unlock_commit(tr->buffer, event);
862 ftrace_trace_stack(tr, flags, 6, pc);
863 ftrace_trace_userstack(tr, flags, pc);
867 struct ring_buffer_event *
868 trace_current_buffer_lock_reserve(unsigned char type, unsigned long len,
869 unsigned long flags, int pc)
871 return trace_buffer_lock_reserve(&global_trace,
872 type, len, flags, pc);
875 void trace_current_buffer_unlock_commit(struct ring_buffer_event *event,
876 unsigned long flags, int pc)
878 return trace_buffer_unlock_commit(&global_trace, event, flags, pc);
882 trace_function(struct trace_array *tr,
883 unsigned long ip, unsigned long parent_ip, unsigned long flags,
886 struct ring_buffer_event *event;
887 struct ftrace_entry *entry;
889 /* If we are reading the ring buffer, don't trace */
890 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
893 event = trace_buffer_lock_reserve(tr, TRACE_FN, sizeof(*entry),
897 entry = ring_buffer_event_data(event);
899 entry->parent_ip = parent_ip;
900 ring_buffer_unlock_commit(tr->buffer, event);
903 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
904 static void __trace_graph_entry(struct trace_array *tr,
905 struct ftrace_graph_ent *trace,
909 struct ring_buffer_event *event;
910 struct ftrace_graph_ent_entry *entry;
912 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
915 event = trace_buffer_lock_reserve(&global_trace, TRACE_GRAPH_ENT,
916 sizeof(*entry), flags, pc);
919 entry = ring_buffer_event_data(event);
920 entry->graph_ent = *trace;
921 ring_buffer_unlock_commit(global_trace.buffer, event);
924 static void __trace_graph_return(struct trace_array *tr,
925 struct ftrace_graph_ret *trace,
929 struct ring_buffer_event *event;
930 struct ftrace_graph_ret_entry *entry;
932 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
935 event = trace_buffer_lock_reserve(&global_trace, TRACE_GRAPH_RET,
936 sizeof(*entry), flags, pc);
939 entry = ring_buffer_event_data(event);
941 ring_buffer_unlock_commit(global_trace.buffer, event);
946 ftrace(struct trace_array *tr, struct trace_array_cpu *data,
947 unsigned long ip, unsigned long parent_ip, unsigned long flags,
950 if (likely(!atomic_read(&data->disabled)))
951 trace_function(tr, ip, parent_ip, flags, pc);
954 static void __ftrace_trace_stack(struct trace_array *tr,
958 #ifdef CONFIG_STACKTRACE
959 struct ring_buffer_event *event;
960 struct stack_entry *entry;
961 struct stack_trace trace;
963 event = trace_buffer_lock_reserve(tr, TRACE_STACK,
964 sizeof(*entry), flags, pc);
967 entry = ring_buffer_event_data(event);
968 memset(&entry->caller, 0, sizeof(entry->caller));
970 trace.nr_entries = 0;
971 trace.max_entries = FTRACE_STACK_ENTRIES;
973 trace.entries = entry->caller;
975 save_stack_trace(&trace);
976 ring_buffer_unlock_commit(tr->buffer, event);
980 static void ftrace_trace_stack(struct trace_array *tr,
984 if (!(trace_flags & TRACE_ITER_STACKTRACE))
987 __ftrace_trace_stack(tr, flags, skip, pc);
990 void __trace_stack(struct trace_array *tr,
994 __ftrace_trace_stack(tr, flags, skip, pc);
997 static void ftrace_trace_userstack(struct trace_array *tr,
998 unsigned long flags, int pc)
1000 #ifdef CONFIG_STACKTRACE
1001 struct ring_buffer_event *event;
1002 struct userstack_entry *entry;
1003 struct stack_trace trace;
1005 if (!(trace_flags & TRACE_ITER_USERSTACKTRACE))
1008 event = trace_buffer_lock_reserve(tr, TRACE_USER_STACK,
1009 sizeof(*entry), flags, pc);
1012 entry = ring_buffer_event_data(event);
1014 memset(&entry->caller, 0, sizeof(entry->caller));
1016 trace.nr_entries = 0;
1017 trace.max_entries = FTRACE_STACK_ENTRIES;
1019 trace.entries = entry->caller;
1021 save_stack_trace_user(&trace);
1022 ring_buffer_unlock_commit(tr->buffer, event);
1027 static void __trace_userstack(struct trace_array *tr, unsigned long flags)
1029 ftrace_trace_userstack(tr, flags, preempt_count());
1034 ftrace_trace_special(void *__tr,
1035 unsigned long arg1, unsigned long arg2, unsigned long arg3,
1038 struct ring_buffer_event *event;
1039 struct trace_array *tr = __tr;
1040 struct special_entry *entry;
1042 event = trace_buffer_lock_reserve(tr, TRACE_SPECIAL,
1043 sizeof(*entry), 0, pc);
1046 entry = ring_buffer_event_data(event);
1050 trace_buffer_unlock_commit(tr, event, 0, pc);
1054 __trace_special(void *__tr, void *__data,
1055 unsigned long arg1, unsigned long arg2, unsigned long arg3)
1057 ftrace_trace_special(__tr, arg1, arg2, arg3, preempt_count());
1061 tracing_sched_switch_trace(struct trace_array *tr,
1062 struct task_struct *prev,
1063 struct task_struct *next,
1064 unsigned long flags, int pc)
1066 struct ring_buffer_event *event;
1067 struct ctx_switch_entry *entry;
1069 event = trace_buffer_lock_reserve(tr, TRACE_CTX,
1070 sizeof(*entry), flags, pc);
1073 entry = ring_buffer_event_data(event);
1074 entry->prev_pid = prev->pid;
1075 entry->prev_prio = prev->prio;
1076 entry->prev_state = prev->state;
1077 entry->next_pid = next->pid;
1078 entry->next_prio = next->prio;
1079 entry->next_state = next->state;
1080 entry->next_cpu = task_cpu(next);
1081 trace_buffer_unlock_commit(tr, event, flags, pc);
1085 tracing_sched_wakeup_trace(struct trace_array *tr,
1086 struct task_struct *wakee,
1087 struct task_struct *curr,
1088 unsigned long flags, int pc)
1090 struct ring_buffer_event *event;
1091 struct ctx_switch_entry *entry;
1093 event = trace_buffer_lock_reserve(tr, TRACE_WAKE,
1094 sizeof(*entry), flags, pc);
1097 entry = ring_buffer_event_data(event);
1098 entry->prev_pid = curr->pid;
1099 entry->prev_prio = curr->prio;
1100 entry->prev_state = curr->state;
1101 entry->next_pid = wakee->pid;
1102 entry->next_prio = wakee->prio;
1103 entry->next_state = wakee->state;
1104 entry->next_cpu = task_cpu(wakee);
1106 ring_buffer_unlock_commit(tr->buffer, event);
1107 ftrace_trace_stack(tr, flags, 6, pc);
1108 ftrace_trace_userstack(tr, flags, pc);
1112 ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3)
1114 struct trace_array *tr = &global_trace;
1115 struct trace_array_cpu *data;
1116 unsigned long flags;
1120 if (tracing_disabled)
1123 pc = preempt_count();
1124 local_irq_save(flags);
1125 cpu = raw_smp_processor_id();
1126 data = tr->data[cpu];
1128 if (likely(atomic_inc_return(&data->disabled) == 1))
1129 ftrace_trace_special(tr, arg1, arg2, arg3, pc);
1131 atomic_dec(&data->disabled);
1132 local_irq_restore(flags);
1135 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1136 int trace_graph_entry(struct ftrace_graph_ent *trace)
1138 struct trace_array *tr = &global_trace;
1139 struct trace_array_cpu *data;
1140 unsigned long flags;
1145 if (!ftrace_trace_task(current))
1148 if (!ftrace_graph_addr(trace->func))
1151 local_irq_save(flags);
1152 cpu = raw_smp_processor_id();
1153 data = tr->data[cpu];
1154 disabled = atomic_inc_return(&data->disabled);
1155 if (likely(disabled == 1)) {
1156 pc = preempt_count();
1157 __trace_graph_entry(tr, trace, flags, pc);
1159 /* Only do the atomic if it is not already set */
1160 if (!test_tsk_trace_graph(current))
1161 set_tsk_trace_graph(current);
1162 atomic_dec(&data->disabled);
1163 local_irq_restore(flags);
1168 void trace_graph_return(struct ftrace_graph_ret *trace)
1170 struct trace_array *tr = &global_trace;
1171 struct trace_array_cpu *data;
1172 unsigned long flags;
1177 local_irq_save(flags);
1178 cpu = raw_smp_processor_id();
1179 data = tr->data[cpu];
1180 disabled = atomic_inc_return(&data->disabled);
1181 if (likely(disabled == 1)) {
1182 pc = preempt_count();
1183 __trace_graph_return(tr, trace, flags, pc);
1186 clear_tsk_trace_graph(current);
1187 atomic_dec(&data->disabled);
1188 local_irq_restore(flags);
1190 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
1194 * trace_vbprintk - write binary msg to tracing buffer
1197 int trace_vbprintk(unsigned long ip, int depth, const char *fmt, va_list args)
1199 static raw_spinlock_t trace_buf_lock =
1200 (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
1201 static u32 trace_buf[TRACE_BUF_SIZE];
1203 struct ring_buffer_event *event;
1204 struct trace_array *tr = &global_trace;
1205 struct trace_array_cpu *data;
1206 struct bprint_entry *entry;
1207 unsigned long flags;
1209 int cpu, len = 0, size, pc;
1211 if (unlikely(tracing_selftest_running || tracing_disabled))
1214 /* Don't pollute graph traces with trace_vprintk internals */
1215 pause_graph_tracing();
1217 pc = preempt_count();
1218 resched = ftrace_preempt_disable();
1219 cpu = raw_smp_processor_id();
1220 data = tr->data[cpu];
1222 if (unlikely(atomic_read(&data->disabled)))
1225 /* Lockdep uses trace_printk for lock tracing */
1226 local_irq_save(flags);
1227 __raw_spin_lock(&trace_buf_lock);
1228 len = vbin_printf(trace_buf, TRACE_BUF_SIZE, fmt, args);
1230 if (len > TRACE_BUF_SIZE || len < 0)
1233 size = sizeof(*entry) + sizeof(u32) * len;
1234 event = trace_buffer_lock_reserve(tr, TRACE_BPRINT, size, flags, pc);
1237 entry = ring_buffer_event_data(event);
1239 entry->depth = depth;
1242 memcpy(entry->buf, trace_buf, sizeof(u32) * len);
1243 ring_buffer_unlock_commit(tr->buffer, event);
1246 __raw_spin_unlock(&trace_buf_lock);
1247 local_irq_restore(flags);
1250 ftrace_preempt_enable(resched);
1251 unpause_graph_tracing();
1255 EXPORT_SYMBOL_GPL(trace_vbprintk);
1257 int trace_vprintk(unsigned long ip, int depth, const char *fmt, va_list args)
1259 static raw_spinlock_t trace_buf_lock = __RAW_SPIN_LOCK_UNLOCKED;
1260 static char trace_buf[TRACE_BUF_SIZE];
1262 struct ring_buffer_event *event;
1263 struct trace_array *tr = &global_trace;
1264 struct trace_array_cpu *data;
1265 int cpu, len = 0, size, pc;
1266 struct print_entry *entry;
1267 unsigned long irq_flags;
1269 if (tracing_disabled || tracing_selftest_running)
1272 pc = preempt_count();
1273 preempt_disable_notrace();
1274 cpu = raw_smp_processor_id();
1275 data = tr->data[cpu];
1277 if (unlikely(atomic_read(&data->disabled)))
1280 pause_graph_tracing();
1281 raw_local_irq_save(irq_flags);
1282 __raw_spin_lock(&trace_buf_lock);
1283 len = vsnprintf(trace_buf, TRACE_BUF_SIZE, fmt, args);
1285 len = min(len, TRACE_BUF_SIZE-1);
1288 size = sizeof(*entry) + len + 1;
1289 event = trace_buffer_lock_reserve(tr, TRACE_PRINT, size, irq_flags, pc);
1292 entry = ring_buffer_event_data(event);
1294 entry->depth = depth;
1296 memcpy(&entry->buf, trace_buf, len);
1297 entry->buf[len] = 0;
1298 ring_buffer_unlock_commit(tr->buffer, event);
1301 __raw_spin_unlock(&trace_buf_lock);
1302 raw_local_irq_restore(irq_flags);
1303 unpause_graph_tracing();
1305 preempt_enable_notrace();
1309 EXPORT_SYMBOL_GPL(trace_vprintk);
1311 enum trace_file_type {
1312 TRACE_FILE_LAT_FMT = 1,
1313 TRACE_FILE_ANNOTATE = 2,
1316 static void trace_iterator_increment(struct trace_iterator *iter)
1318 /* Don't allow ftrace to trace into the ring buffers */
1319 ftrace_disable_cpu();
1322 if (iter->buffer_iter[iter->cpu])
1323 ring_buffer_read(iter->buffer_iter[iter->cpu], NULL);
1325 ftrace_enable_cpu();
1328 static struct trace_entry *
1329 peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts)
1331 struct ring_buffer_event *event;
1332 struct ring_buffer_iter *buf_iter = iter->buffer_iter[cpu];
1334 /* Don't allow ftrace to trace into the ring buffers */
1335 ftrace_disable_cpu();
1338 event = ring_buffer_iter_peek(buf_iter, ts);
1340 event = ring_buffer_peek(iter->tr->buffer, cpu, ts);
1342 ftrace_enable_cpu();
1344 return event ? ring_buffer_event_data(event) : NULL;
1347 static struct trace_entry *
1348 __find_next_entry(struct trace_iterator *iter, int *ent_cpu, u64 *ent_ts)
1350 struct ring_buffer *buffer = iter->tr->buffer;
1351 struct trace_entry *ent, *next = NULL;
1352 int cpu_file = iter->cpu_file;
1353 u64 next_ts = 0, ts;
1358 * If we are in a per_cpu trace file, don't bother by iterating over
1359 * all cpu and peek directly.
1361 if (cpu_file > TRACE_PIPE_ALL_CPU) {
1362 if (ring_buffer_empty_cpu(buffer, cpu_file))
1364 ent = peek_next_entry(iter, cpu_file, ent_ts);
1366 *ent_cpu = cpu_file;
1371 for_each_tracing_cpu(cpu) {
1373 if (ring_buffer_empty_cpu(buffer, cpu))
1376 ent = peek_next_entry(iter, cpu, &ts);
1379 * Pick the entry with the smallest timestamp:
1381 if (ent && (!next || ts < next_ts)) {
1389 *ent_cpu = next_cpu;
1397 /* Find the next real entry, without updating the iterator itself */
1398 struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
1399 int *ent_cpu, u64 *ent_ts)
1401 return __find_next_entry(iter, ent_cpu, ent_ts);
1404 /* Find the next real entry, and increment the iterator to the next entry */
1405 static void *find_next_entry_inc(struct trace_iterator *iter)
1407 iter->ent = __find_next_entry(iter, &iter->cpu, &iter->ts);
1410 trace_iterator_increment(iter);
1412 return iter->ent ? iter : NULL;
1415 static void trace_consume(struct trace_iterator *iter)
1417 /* Don't allow ftrace to trace into the ring buffers */
1418 ftrace_disable_cpu();
1419 ring_buffer_consume(iter->tr->buffer, iter->cpu, &iter->ts);
1420 ftrace_enable_cpu();
1423 static void *s_next(struct seq_file *m, void *v, loff_t *pos)
1425 struct trace_iterator *iter = m->private;
1431 /* can't go backwards */
1436 ent = find_next_entry_inc(iter);
1440 while (ent && iter->idx < i)
1441 ent = find_next_entry_inc(iter);
1449 * No necessary locking here. The worst thing which can
1450 * happen is loosing events consumed at the same time
1451 * by a trace_pipe reader.
1452 * Other than that, we don't risk to crash the ring buffer
1453 * because it serializes the readers.
1455 * The current tracer is copied to avoid a global locking
1458 static void *s_start(struct seq_file *m, loff_t *pos)
1460 struct trace_iterator *iter = m->private;
1461 static struct tracer *old_tracer;
1462 int cpu_file = iter->cpu_file;
1467 /* copy the tracer to avoid using a global lock all around */
1468 mutex_lock(&trace_types_lock);
1469 if (unlikely(old_tracer != current_trace && current_trace)) {
1470 old_tracer = current_trace;
1471 *iter->trace = *current_trace;
1473 mutex_unlock(&trace_types_lock);
1475 atomic_inc(&trace_record_cmdline_disabled);
1477 if (*pos != iter->pos) {
1482 ftrace_disable_cpu();
1484 if (cpu_file == TRACE_PIPE_ALL_CPU) {
1485 for_each_tracing_cpu(cpu)
1486 ring_buffer_iter_reset(iter->buffer_iter[cpu]);
1488 ring_buffer_iter_reset(iter->buffer_iter[cpu_file]);
1491 ftrace_enable_cpu();
1493 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
1498 p = s_next(m, p, &l);
1504 static void s_stop(struct seq_file *m, void *p)
1506 atomic_dec(&trace_record_cmdline_disabled);
1509 static void print_lat_help_header(struct seq_file *m)
1511 seq_puts(m, "# _------=> CPU# \n");
1512 seq_puts(m, "# / _-----=> irqs-off \n");
1513 seq_puts(m, "# | / _----=> need-resched \n");
1514 seq_puts(m, "# || / _---=> hardirq/softirq \n");
1515 seq_puts(m, "# ||| / _--=> preempt-depth \n");
1516 seq_puts(m, "# |||| / \n");
1517 seq_puts(m, "# ||||| delay \n");
1518 seq_puts(m, "# cmd pid ||||| time | caller \n");
1519 seq_puts(m, "# \\ / ||||| \\ | / \n");
1522 static void print_func_help_header(struct seq_file *m)
1524 seq_puts(m, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
1525 seq_puts(m, "# | | | | |\n");
1530 print_trace_header(struct seq_file *m, struct trace_iterator *iter)
1532 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1533 struct trace_array *tr = iter->tr;
1534 struct trace_array_cpu *data = tr->data[tr->cpu];
1535 struct tracer *type = current_trace;
1536 unsigned long total;
1537 unsigned long entries;
1538 const char *name = "preemption";
1543 entries = ring_buffer_entries(iter->tr->buffer);
1545 ring_buffer_overruns(iter->tr->buffer);
1547 seq_printf(m, "# %s latency trace v1.1.5 on %s\n",
1549 seq_puts(m, "# -----------------------------------"
1550 "---------------------------------\n");
1551 seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d |"
1552 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
1553 nsecs_to_usecs(data->saved_latency),
1557 #if defined(CONFIG_PREEMPT_NONE)
1559 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
1561 #elif defined(CONFIG_PREEMPT)
1566 /* These are reserved for later use */
1569 seq_printf(m, " #P:%d)\n", num_online_cpus());
1573 seq_puts(m, "# -----------------\n");
1574 seq_printf(m, "# | task: %.16s-%d "
1575 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
1576 data->comm, data->pid, data->uid, data->nice,
1577 data->policy, data->rt_priority);
1578 seq_puts(m, "# -----------------\n");
1580 if (data->critical_start) {
1581 seq_puts(m, "# => started at: ");
1582 seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
1583 trace_print_seq(m, &iter->seq);
1584 seq_puts(m, "\n# => ended at: ");
1585 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
1586 trace_print_seq(m, &iter->seq);
1593 static void test_cpu_buff_start(struct trace_iterator *iter)
1595 struct trace_seq *s = &iter->seq;
1597 if (!(trace_flags & TRACE_ITER_ANNOTATE))
1600 if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
1603 if (cpumask_test_cpu(iter->cpu, iter->started))
1606 cpumask_set_cpu(iter->cpu, iter->started);
1607 trace_seq_printf(s, "##### CPU %u buffer started ####\n", iter->cpu);
1610 static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
1612 struct trace_seq *s = &iter->seq;
1613 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1614 struct trace_entry *entry;
1615 struct trace_event *event;
1619 test_cpu_buff_start(iter);
1621 event = ftrace_find_event(entry->type);
1623 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1624 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
1625 if (!trace_print_lat_context(iter))
1628 if (!trace_print_context(iter))
1634 return event->trace(iter, sym_flags);
1636 if (!trace_seq_printf(s, "Unknown type %d\n", entry->type))
1639 return TRACE_TYPE_HANDLED;
1641 return TRACE_TYPE_PARTIAL_LINE;
1644 static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
1646 struct trace_seq *s = &iter->seq;
1647 struct trace_entry *entry;
1648 struct trace_event *event;
1652 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1653 if (!trace_seq_printf(s, "%d %d %llu ",
1654 entry->pid, iter->cpu, iter->ts))
1658 event = ftrace_find_event(entry->type);
1660 return event->raw(iter, 0);
1662 if (!trace_seq_printf(s, "%d ?\n", entry->type))
1665 return TRACE_TYPE_HANDLED;
1667 return TRACE_TYPE_PARTIAL_LINE;
1670 static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
1672 struct trace_seq *s = &iter->seq;
1673 unsigned char newline = '\n';
1674 struct trace_entry *entry;
1675 struct trace_event *event;
1679 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1680 SEQ_PUT_HEX_FIELD_RET(s, entry->pid);
1681 SEQ_PUT_HEX_FIELD_RET(s, iter->cpu);
1682 SEQ_PUT_HEX_FIELD_RET(s, iter->ts);
1685 event = ftrace_find_event(entry->type);
1687 enum print_line_t ret = event->hex(iter, 0);
1688 if (ret != TRACE_TYPE_HANDLED)
1692 SEQ_PUT_FIELD_RET(s, newline);
1694 return TRACE_TYPE_HANDLED;
1697 static enum print_line_t print_bprintk_msg_only(struct trace_iterator *iter)
1699 struct trace_seq *s = &iter->seq;
1700 struct trace_entry *entry = iter->ent;
1701 struct bprint_entry *field;
1704 trace_assign_type(field, entry);
1706 ret = trace_seq_bprintf(s, field->fmt, field->buf);
1708 return TRACE_TYPE_PARTIAL_LINE;
1710 return TRACE_TYPE_HANDLED;
1713 static enum print_line_t print_printk_msg_only(struct trace_iterator *iter)
1715 struct trace_seq *s = &iter->seq;
1716 struct trace_entry *entry = iter->ent;
1717 struct print_entry *field;
1720 trace_assign_type(field, entry);
1722 ret = trace_seq_printf(s, "%s", field->buf);
1724 return TRACE_TYPE_PARTIAL_LINE;
1726 return TRACE_TYPE_HANDLED;
1729 static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
1731 struct trace_seq *s = &iter->seq;
1732 struct trace_entry *entry;
1733 struct trace_event *event;
1737 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1738 SEQ_PUT_FIELD_RET(s, entry->pid);
1739 SEQ_PUT_FIELD_RET(s, iter->cpu);
1740 SEQ_PUT_FIELD_RET(s, iter->ts);
1743 event = ftrace_find_event(entry->type);
1744 return event ? event->binary(iter, 0) : TRACE_TYPE_HANDLED;
1747 static int trace_empty(struct trace_iterator *iter)
1751 /* If we are looking at one CPU buffer, only check that one */
1752 if (iter->cpu_file != TRACE_PIPE_ALL_CPU) {
1753 cpu = iter->cpu_file;
1754 if (iter->buffer_iter[cpu]) {
1755 if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
1758 if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu))
1764 for_each_tracing_cpu(cpu) {
1765 if (iter->buffer_iter[cpu]) {
1766 if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
1769 if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu))
1777 static enum print_line_t print_trace_line(struct trace_iterator *iter)
1779 enum print_line_t ret;
1781 if (iter->trace && iter->trace->print_line) {
1782 ret = iter->trace->print_line(iter);
1783 if (ret != TRACE_TYPE_UNHANDLED)
1787 if (iter->ent->type == TRACE_BPRINT &&
1788 trace_flags & TRACE_ITER_PRINTK &&
1789 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
1790 return print_bprintk_msg_only(iter);
1792 if (iter->ent->type == TRACE_PRINT &&
1793 trace_flags & TRACE_ITER_PRINTK &&
1794 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
1795 return print_printk_msg_only(iter);
1797 if (trace_flags & TRACE_ITER_BIN)
1798 return print_bin_fmt(iter);
1800 if (trace_flags & TRACE_ITER_HEX)
1801 return print_hex_fmt(iter);
1803 if (trace_flags & TRACE_ITER_RAW)
1804 return print_raw_fmt(iter);
1806 return print_trace_fmt(iter);
1809 static int s_show(struct seq_file *m, void *v)
1811 struct trace_iterator *iter = v;
1813 if (iter->ent == NULL) {
1815 seq_printf(m, "# tracer: %s\n", iter->trace->name);
1818 if (iter->trace && iter->trace->print_header)
1819 iter->trace->print_header(m);
1820 else if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
1821 /* print nothing if the buffers are empty */
1822 if (trace_empty(iter))
1824 print_trace_header(m, iter);
1825 if (!(trace_flags & TRACE_ITER_VERBOSE))
1826 print_lat_help_header(m);
1828 if (!(trace_flags & TRACE_ITER_VERBOSE))
1829 print_func_help_header(m);
1832 print_trace_line(iter);
1833 trace_print_seq(m, &iter->seq);
1839 static struct seq_operations tracer_seq_ops = {
1846 static struct trace_iterator *
1847 __tracing_open(struct inode *inode, struct file *file)
1849 long cpu_file = (long) inode->i_private;
1850 void *fail_ret = ERR_PTR(-ENOMEM);
1851 struct trace_iterator *iter;
1855 if (tracing_disabled)
1856 return ERR_PTR(-ENODEV);
1858 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1860 return ERR_PTR(-ENOMEM);
1863 * We make a copy of the current tracer to avoid concurrent
1864 * changes on it while we are reading.
1866 mutex_lock(&trace_types_lock);
1867 iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL);
1872 *iter->trace = *current_trace;
1874 if (current_trace && current_trace->print_max)
1877 iter->tr = &global_trace;
1879 mutex_init(&iter->mutex);
1880 iter->cpu_file = cpu_file;
1882 /* Notify the tracer early; before we stop tracing. */
1883 if (iter->trace && iter->trace->open)
1884 iter->trace->open(iter);
1886 /* Annotate start of buffers if we had overruns */
1887 if (ring_buffer_overruns(iter->tr->buffer))
1888 iter->iter_flags |= TRACE_FILE_ANNOTATE;
1890 if (iter->cpu_file == TRACE_PIPE_ALL_CPU) {
1891 for_each_tracing_cpu(cpu) {
1893 iter->buffer_iter[cpu] =
1894 ring_buffer_read_start(iter->tr->buffer, cpu);
1897 cpu = iter->cpu_file;
1898 iter->buffer_iter[cpu] =
1899 ring_buffer_read_start(iter->tr->buffer, cpu);
1902 /* TODO stop tracer */
1903 ret = seq_open(file, &tracer_seq_ops);
1905 fail_ret = ERR_PTR(ret);
1909 m = file->private_data;
1912 /* stop the trace while dumping */
1915 mutex_unlock(&trace_types_lock);
1920 for_each_tracing_cpu(cpu) {
1921 if (iter->buffer_iter[cpu])
1922 ring_buffer_read_finish(iter->buffer_iter[cpu]);
1925 mutex_unlock(&trace_types_lock);
1932 int tracing_open_generic(struct inode *inode, struct file *filp)
1934 if (tracing_disabled)
1937 filp->private_data = inode->i_private;
1941 static int tracing_release(struct inode *inode, struct file *file)
1943 struct seq_file *m = (struct seq_file *)file->private_data;
1944 struct trace_iterator *iter;
1947 if (!(file->f_mode & FMODE_READ))
1952 mutex_lock(&trace_types_lock);
1953 for_each_tracing_cpu(cpu) {
1954 if (iter->buffer_iter[cpu])
1955 ring_buffer_read_finish(iter->buffer_iter[cpu]);
1958 if (iter->trace && iter->trace->close)
1959 iter->trace->close(iter);
1961 /* reenable tracing if it was previously enabled */
1963 mutex_unlock(&trace_types_lock);
1965 seq_release(inode, file);
1966 mutex_destroy(&iter->mutex);
1972 static int tracing_open(struct inode *inode, struct file *file)
1974 struct trace_iterator *iter;
1977 /* If this file was open for write, then erase contents */
1978 if ((file->f_mode & FMODE_WRITE) &&
1979 !(file->f_flags & O_APPEND)) {
1980 long cpu = (long) inode->i_private;
1982 if (cpu == TRACE_PIPE_ALL_CPU)
1983 tracing_reset_online_cpus(&global_trace);
1985 tracing_reset(&global_trace, cpu);
1988 if (file->f_mode & FMODE_READ) {
1989 iter = __tracing_open(inode, file);
1991 ret = PTR_ERR(iter);
1992 else if (trace_flags & TRACE_ITER_LATENCY_FMT)
1993 iter->iter_flags |= TRACE_FILE_LAT_FMT;
1999 t_next(struct seq_file *m, void *v, loff_t *pos)
2001 struct tracer *t = m->private;
2013 static void *t_start(struct seq_file *m, loff_t *pos)
2015 struct tracer *t = m->private;
2018 mutex_lock(&trace_types_lock);
2019 for (; t && l < *pos; t = t_next(m, t, &l))
2025 static void t_stop(struct seq_file *m, void *p)
2027 mutex_unlock(&trace_types_lock);
2030 static int t_show(struct seq_file *m, void *v)
2032 struct tracer *t = v;
2037 seq_printf(m, "%s", t->name);
2046 static struct seq_operations show_traces_seq_ops = {
2053 static int show_traces_open(struct inode *inode, struct file *file)
2057 if (tracing_disabled)
2060 ret = seq_open(file, &show_traces_seq_ops);
2062 struct seq_file *m = file->private_data;
2063 m->private = trace_types;
2070 tracing_write_stub(struct file *filp, const char __user *ubuf,
2071 size_t count, loff_t *ppos)
2076 static const struct file_operations tracing_fops = {
2077 .open = tracing_open,
2079 .write = tracing_write_stub,
2080 .llseek = seq_lseek,
2081 .release = tracing_release,
2084 static const struct file_operations show_traces_fops = {
2085 .open = show_traces_open,
2087 .release = seq_release,
2091 * Only trace on a CPU if the bitmask is set:
2093 static cpumask_var_t tracing_cpumask;
2096 * The tracer itself will not take this lock, but still we want
2097 * to provide a consistent cpumask to user-space:
2099 static DEFINE_MUTEX(tracing_cpumask_update_lock);
2102 * Temporary storage for the character representation of the
2103 * CPU bitmask (and one more byte for the newline):
2105 static char mask_str[NR_CPUS + 1];
2108 tracing_cpumask_read(struct file *filp, char __user *ubuf,
2109 size_t count, loff_t *ppos)
2113 mutex_lock(&tracing_cpumask_update_lock);
2115 len = cpumask_scnprintf(mask_str, count, tracing_cpumask);
2116 if (count - len < 2) {
2120 len += sprintf(mask_str + len, "\n");
2121 count = simple_read_from_buffer(ubuf, count, ppos, mask_str, NR_CPUS+1);
2124 mutex_unlock(&tracing_cpumask_update_lock);
2130 tracing_cpumask_write(struct file *filp, const char __user *ubuf,
2131 size_t count, loff_t *ppos)
2134 cpumask_var_t tracing_cpumask_new;
2136 if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
2139 mutex_lock(&tracing_cpumask_update_lock);
2140 err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
2144 local_irq_disable();
2145 __raw_spin_lock(&ftrace_max_lock);
2146 for_each_tracing_cpu(cpu) {
2148 * Increase/decrease the disabled counter if we are
2149 * about to flip a bit in the cpumask:
2151 if (cpumask_test_cpu(cpu, tracing_cpumask) &&
2152 !cpumask_test_cpu(cpu, tracing_cpumask_new)) {
2153 atomic_inc(&global_trace.data[cpu]->disabled);
2155 if (!cpumask_test_cpu(cpu, tracing_cpumask) &&
2156 cpumask_test_cpu(cpu, tracing_cpumask_new)) {
2157 atomic_dec(&global_trace.data[cpu]->disabled);
2160 __raw_spin_unlock(&ftrace_max_lock);
2163 cpumask_copy(tracing_cpumask, tracing_cpumask_new);
2165 mutex_unlock(&tracing_cpumask_update_lock);
2166 free_cpumask_var(tracing_cpumask_new);
2171 mutex_unlock(&tracing_cpumask_update_lock);
2172 free_cpumask_var(tracing_cpumask);
2177 static const struct file_operations tracing_cpumask_fops = {
2178 .open = tracing_open_generic,
2179 .read = tracing_cpumask_read,
2180 .write = tracing_cpumask_write,
2184 tracing_trace_options_read(struct file *filp, char __user *ubuf,
2185 size_t cnt, loff_t *ppos)
2187 struct tracer_opt *trace_opts;
2195 /* calculate max size */
2196 for (i = 0; trace_options[i]; i++) {
2197 len += strlen(trace_options[i]);
2198 len += 3; /* "no" and newline */
2201 mutex_lock(&trace_types_lock);
2202 tracer_flags = current_trace->flags->val;
2203 trace_opts = current_trace->flags->opts;
2206 * Increase the size with names of options specific
2207 * of the current tracer.
2209 for (i = 0; trace_opts[i].name; i++) {
2210 len += strlen(trace_opts[i].name);
2211 len += 3; /* "no" and newline */
2214 /* +2 for \n and \0 */
2215 buf = kmalloc(len + 2, GFP_KERNEL);
2217 mutex_unlock(&trace_types_lock);
2221 for (i = 0; trace_options[i]; i++) {
2222 if (trace_flags & (1 << i))
2223 r += sprintf(buf + r, "%s\n", trace_options[i]);
2225 r += sprintf(buf + r, "no%s\n", trace_options[i]);
2228 for (i = 0; trace_opts[i].name; i++) {
2229 if (tracer_flags & trace_opts[i].bit)
2230 r += sprintf(buf + r, "%s\n",
2231 trace_opts[i].name);
2233 r += sprintf(buf + r, "no%s\n",
2234 trace_opts[i].name);
2236 mutex_unlock(&trace_types_lock);
2238 WARN_ON(r >= len + 2);
2240 r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2246 /* Try to assign a tracer specific option */
2247 static int set_tracer_option(struct tracer *trace, char *cmp, int neg)
2249 struct tracer_flags *trace_flags = trace->flags;
2250 struct tracer_opt *opts = NULL;
2254 for (i = 0; trace_flags->opts[i].name; i++) {
2255 opts = &trace_flags->opts[i];
2256 len = strlen(opts->name);
2258 if (strncmp(cmp, opts->name, len) == 0) {
2259 ret = trace->set_flag(trace_flags->val,
2265 if (!trace_flags->opts[i].name)
2268 /* Refused to handle */
2273 trace_flags->val &= ~opts->bit;
2275 trace_flags->val |= opts->bit;
2280 static void set_tracer_flags(unsigned int mask, int enabled)
2282 /* do nothing if flag is already set */
2283 if (!!(trace_flags & mask) == !!enabled)
2287 trace_flags |= mask;
2289 trace_flags &= ~mask;
2291 if (mask == TRACE_ITER_GLOBAL_CLK) {
2295 func = trace_clock_global;
2297 func = trace_clock_local;
2299 mutex_lock(&trace_types_lock);
2300 ring_buffer_set_clock(global_trace.buffer, func);
2303 ring_buffer_set_clock(max_tr.buffer, func);
2304 mutex_unlock(&trace_types_lock);
2309 tracing_trace_options_write(struct file *filp, const char __user *ubuf,
2310 size_t cnt, loff_t *ppos)
2318 if (cnt >= sizeof(buf))
2321 if (copy_from_user(&buf, ubuf, cnt))
2326 if (strncmp(buf, "no", 2) == 0) {
2331 for (i = 0; trace_options[i]; i++) {
2332 int len = strlen(trace_options[i]);
2334 if (strncmp(cmp, trace_options[i], len) == 0) {
2335 set_tracer_flags(1 << i, !neg);
2340 /* If no option could be set, test the specific tracer options */
2341 if (!trace_options[i]) {
2342 mutex_lock(&trace_types_lock);
2343 ret = set_tracer_option(current_trace, cmp, neg);
2344 mutex_unlock(&trace_types_lock);
2354 static const struct file_operations tracing_iter_fops = {
2355 .open = tracing_open_generic,
2356 .read = tracing_trace_options_read,
2357 .write = tracing_trace_options_write,
2360 static const char readme_msg[] =
2361 "tracing mini-HOWTO:\n\n"
2363 "# mount -t debugfs nodev /debug\n\n"
2364 "# cat /debug/tracing/available_tracers\n"
2365 "wakeup preemptirqsoff preemptoff irqsoff ftrace sched_switch none\n\n"
2366 "# cat /debug/tracing/current_tracer\n"
2368 "# echo sched_switch > /debug/tracing/current_tracer\n"
2369 "# cat /debug/tracing/current_tracer\n"
2371 "# cat /debug/tracing/trace_options\n"
2372 "noprint-parent nosym-offset nosym-addr noverbose\n"
2373 "# echo print-parent > /debug/tracing/trace_options\n"
2374 "# echo 1 > /debug/tracing/tracing_enabled\n"
2375 "# cat /debug/tracing/trace > /tmp/trace.txt\n"
2376 "echo 0 > /debug/tracing/tracing_enabled\n"
2380 tracing_readme_read(struct file *filp, char __user *ubuf,
2381 size_t cnt, loff_t *ppos)
2383 return simple_read_from_buffer(ubuf, cnt, ppos,
2384 readme_msg, strlen(readme_msg));
2387 static const struct file_operations tracing_readme_fops = {
2388 .open = tracing_open_generic,
2389 .read = tracing_readme_read,
2393 tracing_ctrl_read(struct file *filp, char __user *ubuf,
2394 size_t cnt, loff_t *ppos)
2399 r = sprintf(buf, "%u\n", tracer_enabled);
2400 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2404 tracing_ctrl_write(struct file *filp, const char __user *ubuf,
2405 size_t cnt, loff_t *ppos)
2407 struct trace_array *tr = filp->private_data;
2412 if (cnt >= sizeof(buf))
2415 if (copy_from_user(&buf, ubuf, cnt))
2420 ret = strict_strtoul(buf, 10, &val);
2426 mutex_lock(&trace_types_lock);
2427 if (tracer_enabled ^ val) {
2430 if (current_trace->start)
2431 current_trace->start(tr);
2436 if (current_trace->stop)
2437 current_trace->stop(tr);
2440 mutex_unlock(&trace_types_lock);
2448 tracing_set_trace_read(struct file *filp, char __user *ubuf,
2449 size_t cnt, loff_t *ppos)
2451 char buf[max_tracer_type_len+2];
2454 mutex_lock(&trace_types_lock);
2456 r = sprintf(buf, "%s\n", current_trace->name);
2458 r = sprintf(buf, "\n");
2459 mutex_unlock(&trace_types_lock);
2461 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2464 int tracer_init(struct tracer *t, struct trace_array *tr)
2466 tracing_reset_online_cpus(tr);
2470 static int tracing_resize_ring_buffer(unsigned long size)
2475 * If kernel or user changes the size of the ring buffer
2476 * we use the size that was given, and we can forget about
2477 * expanding it later.
2479 ring_buffer_expanded = 1;
2481 ret = ring_buffer_resize(global_trace.buffer, size);
2485 ret = ring_buffer_resize(max_tr.buffer, size);
2489 r = ring_buffer_resize(global_trace.buffer,
2490 global_trace.entries);
2493 * AARGH! We are left with different
2494 * size max buffer!!!!
2495 * The max buffer is our "snapshot" buffer.
2496 * When a tracer needs a snapshot (one of the
2497 * latency tracers), it swaps the max buffer
2498 * with the saved snap shot. We succeeded to
2499 * update the size of the main buffer, but failed to
2500 * update the size of the max buffer. But when we tried
2501 * to reset the main buffer to the original size, we
2502 * failed there too. This is very unlikely to
2503 * happen, but if it does, warn and kill all
2507 tracing_disabled = 1;
2512 global_trace.entries = size;
2518 * tracing_update_buffers - used by tracing facility to expand ring buffers
2520 * To save on memory when the tracing is never used on a system with it
2521 * configured in. The ring buffers are set to a minimum size. But once
2522 * a user starts to use the tracing facility, then they need to grow
2523 * to their default size.
2525 * This function is to be called when a tracer is about to be used.
2527 int tracing_update_buffers(void)
2531 mutex_lock(&trace_types_lock);
2532 if (!ring_buffer_expanded)
2533 ret = tracing_resize_ring_buffer(trace_buf_size);
2534 mutex_unlock(&trace_types_lock);
2539 struct trace_option_dentry;
2541 static struct trace_option_dentry *
2542 create_trace_option_files(struct tracer *tracer);
2545 destroy_trace_option_files(struct trace_option_dentry *topts);
2547 static int tracing_set_tracer(const char *buf)
2549 static struct trace_option_dentry *topts;
2550 struct trace_array *tr = &global_trace;
2554 mutex_lock(&trace_types_lock);
2556 if (!ring_buffer_expanded) {
2557 ret = tracing_resize_ring_buffer(trace_buf_size);
2563 for (t = trace_types; t; t = t->next) {
2564 if (strcmp(t->name, buf) == 0)
2571 if (t == current_trace)
2574 trace_branch_disable();
2575 if (current_trace && current_trace->reset)
2576 current_trace->reset(tr);
2578 destroy_trace_option_files(topts);
2582 topts = create_trace_option_files(current_trace);
2585 ret = tracer_init(t, tr);
2590 trace_branch_enable(tr);
2592 mutex_unlock(&trace_types_lock);
2598 tracing_set_trace_write(struct file *filp, const char __user *ubuf,
2599 size_t cnt, loff_t *ppos)
2601 char buf[max_tracer_type_len+1];
2608 if (cnt > max_tracer_type_len)
2609 cnt = max_tracer_type_len;
2611 if (copy_from_user(&buf, ubuf, cnt))
2616 /* strip ending whitespace. */
2617 for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
2620 err = tracing_set_tracer(buf);
2630 tracing_max_lat_read(struct file *filp, char __user *ubuf,
2631 size_t cnt, loff_t *ppos)
2633 unsigned long *ptr = filp->private_data;
2637 r = snprintf(buf, sizeof(buf), "%ld\n",
2638 *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
2639 if (r > sizeof(buf))
2641 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2645 tracing_max_lat_write(struct file *filp, const char __user *ubuf,
2646 size_t cnt, loff_t *ppos)
2648 unsigned long *ptr = filp->private_data;
2653 if (cnt >= sizeof(buf))
2656 if (copy_from_user(&buf, ubuf, cnt))
2661 ret = strict_strtoul(buf, 10, &val);
2670 static int tracing_open_pipe(struct inode *inode, struct file *filp)
2672 long cpu_file = (long) inode->i_private;
2673 struct trace_iterator *iter;
2676 if (tracing_disabled)
2679 mutex_lock(&trace_types_lock);
2681 /* We only allow one reader per cpu */
2682 if (cpu_file == TRACE_PIPE_ALL_CPU) {
2683 if (!cpumask_empty(tracing_reader_cpumask)) {
2687 cpumask_setall(tracing_reader_cpumask);
2689 if (!cpumask_test_cpu(cpu_file, tracing_reader_cpumask))
2690 cpumask_set_cpu(cpu_file, tracing_reader_cpumask);
2697 /* create a buffer to store the information to pass to userspace */
2698 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2705 * We make a copy of the current tracer to avoid concurrent
2706 * changes on it while we are reading.
2708 iter->trace = kmalloc(sizeof(*iter->trace), GFP_KERNEL);
2714 *iter->trace = *current_trace;
2716 if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
2721 /* trace pipe does not show start of buffer */
2722 cpumask_setall(iter->started);
2724 iter->cpu_file = cpu_file;
2725 iter->tr = &global_trace;
2726 mutex_init(&iter->mutex);
2727 filp->private_data = iter;
2729 if (iter->trace->pipe_open)
2730 iter->trace->pipe_open(iter);
2733 mutex_unlock(&trace_types_lock);
2739 mutex_unlock(&trace_types_lock);
2743 static int tracing_release_pipe(struct inode *inode, struct file *file)
2745 struct trace_iterator *iter = file->private_data;
2747 mutex_lock(&trace_types_lock);
2749 if (iter->cpu_file == TRACE_PIPE_ALL_CPU)
2750 cpumask_clear(tracing_reader_cpumask);
2752 cpumask_clear_cpu(iter->cpu_file, tracing_reader_cpumask);
2754 mutex_unlock(&trace_types_lock);
2756 free_cpumask_var(iter->started);
2757 mutex_destroy(&iter->mutex);
2765 tracing_poll_pipe(struct file *filp, poll_table *poll_table)
2767 struct trace_iterator *iter = filp->private_data;
2769 if (trace_flags & TRACE_ITER_BLOCK) {
2771 * Always select as readable when in blocking mode
2773 return POLLIN | POLLRDNORM;
2775 if (!trace_empty(iter))
2776 return POLLIN | POLLRDNORM;
2777 poll_wait(filp, &trace_wait, poll_table);
2778 if (!trace_empty(iter))
2779 return POLLIN | POLLRDNORM;
2786 void default_wait_pipe(struct trace_iterator *iter)
2790 prepare_to_wait(&trace_wait, &wait, TASK_INTERRUPTIBLE);
2792 if (trace_empty(iter))
2795 finish_wait(&trace_wait, &wait);
2799 * This is a make-shift waitqueue.
2800 * A tracer might use this callback on some rare cases:
2802 * 1) the current tracer might hold the runqueue lock when it wakes up
2803 * a reader, hence a deadlock (sched, function, and function graph tracers)
2804 * 2) the function tracers, trace all functions, we don't want
2805 * the overhead of calling wake_up and friends
2806 * (and tracing them too)
2808 * Anyway, this is really very primitive wakeup.
2810 void poll_wait_pipe(struct trace_iterator *iter)
2812 set_current_state(TASK_INTERRUPTIBLE);
2813 /* sleep for 100 msecs, and try again. */
2814 schedule_timeout(HZ / 10);
2817 /* Must be called with trace_types_lock mutex held. */
2818 static int tracing_wait_pipe(struct file *filp)
2820 struct trace_iterator *iter = filp->private_data;
2822 while (trace_empty(iter)) {
2824 if ((filp->f_flags & O_NONBLOCK)) {
2828 mutex_unlock(&iter->mutex);
2830 iter->trace->wait_pipe(iter);
2832 mutex_lock(&iter->mutex);
2834 if (signal_pending(current))
2838 * We block until we read something and tracing is disabled.
2839 * We still block if tracing is disabled, but we have never
2840 * read anything. This allows a user to cat this file, and
2841 * then enable tracing. But after we have read something,
2842 * we give an EOF when tracing is again disabled.
2844 * iter->pos will be 0 if we haven't read anything.
2846 if (!tracer_enabled && iter->pos)
2857 tracing_read_pipe(struct file *filp, char __user *ubuf,
2858 size_t cnt, loff_t *ppos)
2860 struct trace_iterator *iter = filp->private_data;
2861 static struct tracer *old_tracer;
2864 /* return any leftover data */
2865 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
2869 trace_seq_init(&iter->seq);
2871 /* copy the tracer to avoid using a global lock all around */
2872 mutex_lock(&trace_types_lock);
2873 if (unlikely(old_tracer != current_trace && current_trace)) {
2874 old_tracer = current_trace;
2875 *iter->trace = *current_trace;
2877 mutex_unlock(&trace_types_lock);
2880 * Avoid more than one consumer on a single file descriptor
2881 * This is just a matter of traces coherency, the ring buffer itself
2884 mutex_lock(&iter->mutex);
2885 if (iter->trace->read) {
2886 sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
2892 sret = tracing_wait_pipe(filp);
2896 /* stop when tracing is finished */
2897 if (trace_empty(iter)) {
2902 if (cnt >= PAGE_SIZE)
2903 cnt = PAGE_SIZE - 1;
2905 /* reset all but tr, trace, and overruns */
2906 memset(&iter->seq, 0,
2907 sizeof(struct trace_iterator) -
2908 offsetof(struct trace_iterator, seq));
2911 while (find_next_entry_inc(iter) != NULL) {
2912 enum print_line_t ret;
2913 int len = iter->seq.len;
2915 ret = print_trace_line(iter);
2916 if (ret == TRACE_TYPE_PARTIAL_LINE) {
2917 /* don't print partial lines */
2918 iter->seq.len = len;
2921 if (ret != TRACE_TYPE_NO_CONSUME)
2922 trace_consume(iter);
2924 if (iter->seq.len >= cnt)
2928 /* Now copy what we have to the user */
2929 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
2930 if (iter->seq.readpos >= iter->seq.len)
2931 trace_seq_init(&iter->seq);
2934 * If there was nothing to send to user, inspite of consuming trace
2935 * entries, go back to wait for more entries.
2941 mutex_unlock(&iter->mutex);
2946 static void tracing_pipe_buf_release(struct pipe_inode_info *pipe,
2947 struct pipe_buffer *buf)
2949 __free_page(buf->page);
2952 static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
2955 __free_page(spd->pages[idx]);
2958 static struct pipe_buf_operations tracing_pipe_buf_ops = {
2960 .map = generic_pipe_buf_map,
2961 .unmap = generic_pipe_buf_unmap,
2962 .confirm = generic_pipe_buf_confirm,
2963 .release = tracing_pipe_buf_release,
2964 .steal = generic_pipe_buf_steal,
2965 .get = generic_pipe_buf_get,
2969 tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
2974 /* Seq buffer is page-sized, exactly what we need. */
2976 count = iter->seq.len;
2977 ret = print_trace_line(iter);
2978 count = iter->seq.len - count;
2981 iter->seq.len -= count;
2984 if (ret == TRACE_TYPE_PARTIAL_LINE) {
2985 iter->seq.len -= count;
2989 trace_consume(iter);
2991 if (!find_next_entry_inc(iter)) {
3001 static ssize_t tracing_splice_read_pipe(struct file *filp,
3003 struct pipe_inode_info *pipe,
3007 struct page *pages[PIPE_BUFFERS];
3008 struct partial_page partial[PIPE_BUFFERS];
3009 struct trace_iterator *iter = filp->private_data;
3010 struct splice_pipe_desc spd = {
3013 .nr_pages = 0, /* This gets updated below. */
3015 .ops = &tracing_pipe_buf_ops,
3016 .spd_release = tracing_spd_release_pipe,
3018 static struct tracer *old_tracer;
3023 /* copy the tracer to avoid using a global lock all around */
3024 mutex_lock(&trace_types_lock);
3025 if (unlikely(old_tracer != current_trace && current_trace)) {
3026 old_tracer = current_trace;
3027 *iter->trace = *current_trace;
3029 mutex_unlock(&trace_types_lock);
3031 mutex_lock(&iter->mutex);
3033 if (iter->trace->splice_read) {
3034 ret = iter->trace->splice_read(iter, filp,
3035 ppos, pipe, len, flags);
3040 ret = tracing_wait_pipe(filp);
3044 if (!iter->ent && !find_next_entry_inc(iter)) {
3049 /* Fill as many pages as possible. */
3050 for (i = 0, rem = len; i < PIPE_BUFFERS && rem; i++) {
3051 pages[i] = alloc_page(GFP_KERNEL);
3055 rem = tracing_fill_pipe_page(rem, iter);
3057 /* Copy the data into the page, so we can start over. */
3058 ret = trace_seq_to_buffer(&iter->seq,
3059 page_address(pages[i]),
3062 __free_page(pages[i]);
3065 partial[i].offset = 0;
3066 partial[i].len = iter->seq.len;
3068 trace_seq_init(&iter->seq);
3071 mutex_unlock(&iter->mutex);
3075 return splice_to_pipe(pipe, &spd);
3078 mutex_unlock(&iter->mutex);
3084 tracing_entries_read(struct file *filp, char __user *ubuf,
3085 size_t cnt, loff_t *ppos)
3087 struct trace_array *tr = filp->private_data;
3091 mutex_lock(&trace_types_lock);
3092 if (!ring_buffer_expanded)
3093 r = sprintf(buf, "%lu (expanded: %lu)\n",
3095 trace_buf_size >> 10);
3097 r = sprintf(buf, "%lu\n", tr->entries >> 10);
3098 mutex_unlock(&trace_types_lock);
3100 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
3104 tracing_entries_write(struct file *filp, const char __user *ubuf,
3105 size_t cnt, loff_t *ppos)
3111 if (cnt >= sizeof(buf))
3114 if (copy_from_user(&buf, ubuf, cnt))
3119 ret = strict_strtoul(buf, 10, &val);
3123 /* must have at least 1 entry */
3127 mutex_lock(&trace_types_lock);
3131 /* disable all cpu buffers */
3132 for_each_tracing_cpu(cpu) {
3133 if (global_trace.data[cpu])
3134 atomic_inc(&global_trace.data[cpu]->disabled);
3135 if (max_tr.data[cpu])
3136 atomic_inc(&max_tr.data[cpu]->disabled);
3139 /* value is in KB */
3142 if (val != global_trace.entries) {
3143 ret = tracing_resize_ring_buffer(val);
3152 /* If check pages failed, return ENOMEM */
3153 if (tracing_disabled)
3156 for_each_tracing_cpu(cpu) {
3157 if (global_trace.data[cpu])
3158 atomic_dec(&global_trace.data[cpu]->disabled);
3159 if (max_tr.data[cpu])
3160 atomic_dec(&max_tr.data[cpu]->disabled);
3164 max_tr.entries = global_trace.entries;
3165 mutex_unlock(&trace_types_lock);
3170 static int mark_printk(const char *fmt, ...)
3174 va_start(args, fmt);
3175 ret = trace_vprintk(0, -1, fmt, args);
3181 tracing_mark_write(struct file *filp, const char __user *ubuf,
3182 size_t cnt, loff_t *fpos)
3187 if (tracing_disabled)
3190 if (cnt > TRACE_BUF_SIZE)
3191 cnt = TRACE_BUF_SIZE;
3193 buf = kmalloc(cnt + 1, GFP_KERNEL);
3197 if (copy_from_user(buf, ubuf, cnt)) {
3202 /* Cut from the first nil or newline. */
3204 end = strchr(buf, '\n');
3208 cnt = mark_printk("%s\n", buf);
3215 static const struct file_operations tracing_max_lat_fops = {
3216 .open = tracing_open_generic,
3217 .read = tracing_max_lat_read,
3218 .write = tracing_max_lat_write,
3221 static const struct file_operations tracing_ctrl_fops = {
3222 .open = tracing_open_generic,
3223 .read = tracing_ctrl_read,
3224 .write = tracing_ctrl_write,
3227 static const struct file_operations set_tracer_fops = {
3228 .open = tracing_open_generic,
3229 .read = tracing_set_trace_read,
3230 .write = tracing_set_trace_write,
3233 static const struct file_operations tracing_pipe_fops = {
3234 .open = tracing_open_pipe,
3235 .poll = tracing_poll_pipe,
3236 .read = tracing_read_pipe,
3237 .splice_read = tracing_splice_read_pipe,
3238 .release = tracing_release_pipe,
3241 static const struct file_operations tracing_entries_fops = {
3242 .open = tracing_open_generic,
3243 .read = tracing_entries_read,
3244 .write = tracing_entries_write,
3247 static const struct file_operations tracing_mark_fops = {
3248 .open = tracing_open_generic,
3249 .write = tracing_mark_write,
3252 struct ftrace_buffer_info {
3253 struct trace_array *tr;
3259 static int tracing_buffers_open(struct inode *inode, struct file *filp)
3261 int cpu = (int)(long)inode->i_private;
3262 struct ftrace_buffer_info *info;
3264 if (tracing_disabled)
3267 info = kzalloc(sizeof(*info), GFP_KERNEL);
3271 info->tr = &global_trace;
3273 info->spare = ring_buffer_alloc_read_page(info->tr->buffer);
3274 /* Force reading ring buffer for first read */
3275 info->read = (unsigned int)-1;
3279 filp->private_data = info;
3289 tracing_buffers_read(struct file *filp, char __user *ubuf,
3290 size_t count, loff_t *ppos)
3292 struct ftrace_buffer_info *info = filp->private_data;
3300 /* Do we have previous read data to read? */
3301 if (info->read < PAGE_SIZE)
3306 ret = ring_buffer_read_page(info->tr->buffer,
3313 pos = ring_buffer_page_len(info->spare);
3315 if (pos < PAGE_SIZE)
3316 memset(info->spare + pos, 0, PAGE_SIZE - pos);
3319 size = PAGE_SIZE - info->read;
3323 ret = copy_to_user(ubuf, info->spare + info->read, size);
3334 static int tracing_buffers_release(struct inode *inode, struct file *file)
3336 struct ftrace_buffer_info *info = file->private_data;
3338 ring_buffer_free_read_page(info->tr->buffer, info->spare);
3345 struct ring_buffer *buffer;
3350 static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
3351 struct pipe_buffer *buf)
3353 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
3358 ring_buffer_free_read_page(ref->buffer, ref->page);
3363 static int buffer_pipe_buf_steal(struct pipe_inode_info *pipe,
3364 struct pipe_buffer *buf)
3369 static void buffer_pipe_buf_get(struct pipe_inode_info *pipe,
3370 struct pipe_buffer *buf)
3372 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
3377 /* Pipe buffer operations for a buffer. */
3378 static struct pipe_buf_operations buffer_pipe_buf_ops = {
3380 .map = generic_pipe_buf_map,
3381 .unmap = generic_pipe_buf_unmap,
3382 .confirm = generic_pipe_buf_confirm,
3383 .release = buffer_pipe_buf_release,
3384 .steal = buffer_pipe_buf_steal,
3385 .get = buffer_pipe_buf_get,
3389 * Callback from splice_to_pipe(), if we need to release some pages
3390 * at the end of the spd in case we error'ed out in filling the pipe.
3392 static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
3394 struct buffer_ref *ref =
3395 (struct buffer_ref *)spd->partial[i].private;
3400 ring_buffer_free_read_page(ref->buffer, ref->page);
3402 spd->partial[i].private = 0;
3406 tracing_buffers_splice_read(struct file *file, loff_t *ppos,
3407 struct pipe_inode_info *pipe, size_t len,
3410 struct ftrace_buffer_info *info = file->private_data;
3411 struct partial_page partial[PIPE_BUFFERS];
3412 struct page *pages[PIPE_BUFFERS];
3413 struct splice_pipe_desc spd = {
3417 .ops = &buffer_pipe_buf_ops,
3418 .spd_release = buffer_spd_release,
3420 struct buffer_ref *ref;
3425 * We can't seek on a buffer input
3427 if (unlikely(*ppos))
3431 for (i = 0; i < PIPE_BUFFERS && len; i++, len -= size) {
3435 ref = kzalloc(sizeof(*ref), GFP_KERNEL);
3439 ref->buffer = info->tr->buffer;
3440 ref->page = ring_buffer_alloc_read_page(ref->buffer);
3446 r = ring_buffer_read_page(ref->buffer, &ref->page,
3449 ring_buffer_free_read_page(ref->buffer,
3456 * zero out any left over data, this is going to
3459 size = ring_buffer_page_len(ref->page);
3460 if (size < PAGE_SIZE)
3461 memset(ref->page + size, 0, PAGE_SIZE - size);
3463 page = virt_to_page(ref->page);
3465 spd.pages[i] = page;
3466 spd.partial[i].len = PAGE_SIZE;
3467 spd.partial[i].offset = 0;
3468 spd.partial[i].private = (unsigned long)ref;
3474 /* did we read anything? */
3475 if (!spd.nr_pages) {
3476 if (flags & SPLICE_F_NONBLOCK)
3484 ret = splice_to_pipe(pipe, &spd);
3489 static const struct file_operations tracing_buffers_fops = {
3490 .open = tracing_buffers_open,
3491 .read = tracing_buffers_read,
3492 .release = tracing_buffers_release,
3493 .splice_read = tracing_buffers_splice_read,
3494 .llseek = no_llseek,
3497 #ifdef CONFIG_DYNAMIC_FTRACE
3499 int __weak ftrace_arch_read_dyn_info(char *buf, int size)
3505 tracing_read_dyn_info(struct file *filp, char __user *ubuf,
3506 size_t cnt, loff_t *ppos)
3508 static char ftrace_dyn_info_buffer[1024];
3509 static DEFINE_MUTEX(dyn_info_mutex);
3510 unsigned long *p = filp->private_data;
3511 char *buf = ftrace_dyn_info_buffer;
3512 int size = ARRAY_SIZE(ftrace_dyn_info_buffer);
3515 mutex_lock(&dyn_info_mutex);
3516 r = sprintf(buf, "%ld ", *p);
3518 r += ftrace_arch_read_dyn_info(buf+r, (size-1)-r);
3521 r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
3523 mutex_unlock(&dyn_info_mutex);
3528 static const struct file_operations tracing_dyn_info_fops = {
3529 .open = tracing_open_generic,
3530 .read = tracing_read_dyn_info,
3534 static struct dentry *d_tracer;
3536 struct dentry *tracing_init_dentry(void)
3543 d_tracer = debugfs_create_dir("tracing", NULL);
3545 if (!d_tracer && !once) {
3547 pr_warning("Could not create debugfs directory 'tracing'\n");
3554 static struct dentry *d_percpu;
3556 struct dentry *tracing_dentry_percpu(void)
3559 struct dentry *d_tracer;
3564 d_tracer = tracing_init_dentry();
3569 d_percpu = debugfs_create_dir("per_cpu", d_tracer);
3571 if (!d_percpu && !once) {
3573 pr_warning("Could not create debugfs directory 'per_cpu'\n");
3580 static void tracing_init_debugfs_percpu(long cpu)
3582 struct dentry *d_percpu = tracing_dentry_percpu();
3583 struct dentry *entry, *d_cpu;
3584 /* strlen(cpu) + MAX(log10(cpu)) + '\0' */
3587 if (cpu > 999 || cpu < 0)
3590 sprintf(cpu_dir, "cpu%ld", cpu);
3591 d_cpu = debugfs_create_dir(cpu_dir, d_percpu);
3593 pr_warning("Could not create debugfs '%s' entry\n", cpu_dir);
3597 /* per cpu trace_pipe */
3598 entry = debugfs_create_file("trace_pipe", 0444, d_cpu,
3599 (void *) cpu, &tracing_pipe_fops);
3601 pr_warning("Could not create debugfs 'trace_pipe' entry\n");
3604 entry = debugfs_create_file("trace", 0644, d_cpu,
3605 (void *) cpu, &tracing_fops);
3607 pr_warning("Could not create debugfs 'trace' entry\n");
3609 entry = debugfs_create_file("trace_pipe_raw", 0444, d_cpu,
3610 (void *) cpu, &tracing_buffers_fops);
3612 pr_warning("Could not create debugfs 'trace_pipe_raw' entry\n");
3615 #ifdef CONFIG_FTRACE_SELFTEST
3616 /* Let selftest have access to static functions in this file */
3617 #include "trace_selftest.c"
3620 struct trace_option_dentry {
3621 struct tracer_opt *opt;
3622 struct tracer_flags *flags;
3623 struct dentry *entry;
3627 trace_options_read(struct file *filp, char __user *ubuf, size_t cnt,
3630 struct trace_option_dentry *topt = filp->private_data;
3633 if (topt->flags->val & topt->opt->bit)
3638 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
3642 trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt,
3645 struct trace_option_dentry *topt = filp->private_data;
3650 if (cnt >= sizeof(buf))
3653 if (copy_from_user(&buf, ubuf, cnt))
3658 ret = strict_strtoul(buf, 10, &val);
3665 /* do nothing if already cleared */
3666 if (!(topt->flags->val & topt->opt->bit))
3669 mutex_lock(&trace_types_lock);
3670 if (current_trace->set_flag)
3671 ret = current_trace->set_flag(topt->flags->val,
3673 mutex_unlock(&trace_types_lock);
3676 topt->flags->val &= ~topt->opt->bit;
3679 /* do nothing if already set */
3680 if (topt->flags->val & topt->opt->bit)
3683 mutex_lock(&trace_types_lock);
3684 if (current_trace->set_flag)
3685 ret = current_trace->set_flag(topt->flags->val,
3687 mutex_unlock(&trace_types_lock);
3690 topt->flags->val |= topt->opt->bit;
3703 static const struct file_operations trace_options_fops = {
3704 .open = tracing_open_generic,
3705 .read = trace_options_read,
3706 .write = trace_options_write,
3710 trace_options_core_read(struct file *filp, char __user *ubuf, size_t cnt,
3713 long index = (long)filp->private_data;
3716 if (trace_flags & (1 << index))
3721 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
3725 trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
3728 long index = (long)filp->private_data;
3733 if (cnt >= sizeof(buf))
3736 if (copy_from_user(&buf, ubuf, cnt))
3741 ret = strict_strtoul(buf, 10, &val);
3747 trace_flags &= ~(1 << index);
3750 trace_flags |= 1 << index;
3762 static const struct file_operations trace_options_core_fops = {
3763 .open = tracing_open_generic,
3764 .read = trace_options_core_read,
3765 .write = trace_options_core_write,
3768 static struct dentry *trace_options_init_dentry(void)
3770 struct dentry *d_tracer;
3771 static struct dentry *t_options;
3776 d_tracer = tracing_init_dentry();
3780 t_options = debugfs_create_dir("options", d_tracer);
3782 pr_warning("Could not create debugfs directory 'options'\n");
3790 create_trace_option_file(struct trace_option_dentry *topt,
3791 struct tracer_flags *flags,
3792 struct tracer_opt *opt)
3794 struct dentry *t_options;
3795 struct dentry *entry;
3797 t_options = trace_options_init_dentry();
3801 topt->flags = flags;
3804 entry = debugfs_create_file(opt->name, 0644, t_options, topt,
3805 &trace_options_fops);
3807 topt->entry = entry;
3811 static struct trace_option_dentry *
3812 create_trace_option_files(struct tracer *tracer)
3814 struct trace_option_dentry *topts;
3815 struct tracer_flags *flags;
3816 struct tracer_opt *opts;
3822 flags = tracer->flags;
3824 if (!flags || !flags->opts)
3829 for (cnt = 0; opts[cnt].name; cnt++)
3832 topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL);
3836 for (cnt = 0; opts[cnt].name; cnt++)
3837 create_trace_option_file(&topts[cnt], flags,
3844 destroy_trace_option_files(struct trace_option_dentry *topts)
3851 for (cnt = 0; topts[cnt].opt; cnt++) {
3852 if (topts[cnt].entry)
3853 debugfs_remove(topts[cnt].entry);
3859 static struct dentry *
3860 create_trace_option_core_file(const char *option, long index)
3862 struct dentry *t_options;
3863 struct dentry *entry;
3865 t_options = trace_options_init_dentry();
3869 entry = debugfs_create_file(option, 0644, t_options, (void *)index,
3870 &trace_options_core_fops);
3875 static __init void create_trace_options_dir(void)
3877 struct dentry *t_options;
3878 struct dentry *entry;
3881 t_options = trace_options_init_dentry();
3885 for (i = 0; trace_options[i]; i++) {
3886 entry = create_trace_option_core_file(trace_options[i], i);
3888 pr_warning("Could not create debugfs %s entry\n",
3893 static __init int tracer_init_debugfs(void)
3895 struct dentry *d_tracer;
3896 struct dentry *entry;
3899 d_tracer = tracing_init_dentry();
3901 entry = debugfs_create_file("tracing_enabled", 0644, d_tracer,
3902 &global_trace, &tracing_ctrl_fops);
3904 pr_warning("Could not create debugfs 'tracing_enabled' entry\n");
3906 entry = debugfs_create_file("trace_options", 0644, d_tracer,
3907 NULL, &tracing_iter_fops);
3909 pr_warning("Could not create debugfs 'trace_options' entry\n");
3911 create_trace_options_dir();
3913 entry = debugfs_create_file("tracing_cpumask", 0644, d_tracer,
3914 NULL, &tracing_cpumask_fops);
3916 pr_warning("Could not create debugfs 'tracing_cpumask' entry\n");
3918 entry = debugfs_create_file("trace", 0644, d_tracer,
3919 (void *) TRACE_PIPE_ALL_CPU, &tracing_fops);
3921 pr_warning("Could not create debugfs 'trace' entry\n");
3923 entry = debugfs_create_file("available_tracers", 0444, d_tracer,
3924 &global_trace, &show_traces_fops);
3926 pr_warning("Could not create debugfs 'available_tracers' entry\n");
3928 entry = debugfs_create_file("current_tracer", 0444, d_tracer,
3929 &global_trace, &set_tracer_fops);
3931 pr_warning("Could not create debugfs 'current_tracer' entry\n");
3933 entry = debugfs_create_file("tracing_max_latency", 0644, d_tracer,
3934 &tracing_max_latency,
3935 &tracing_max_lat_fops);
3937 pr_warning("Could not create debugfs "
3938 "'tracing_max_latency' entry\n");
3940 entry = debugfs_create_file("tracing_thresh", 0644, d_tracer,
3941 &tracing_thresh, &tracing_max_lat_fops);
3943 pr_warning("Could not create debugfs "
3944 "'tracing_thresh' entry\n");
3945 entry = debugfs_create_file("README", 0644, d_tracer,
3946 NULL, &tracing_readme_fops);
3948 pr_warning("Could not create debugfs 'README' entry\n");
3950 entry = debugfs_create_file("trace_pipe", 0444, d_tracer,
3951 (void *) TRACE_PIPE_ALL_CPU, &tracing_pipe_fops);
3953 pr_warning("Could not create debugfs "
3954 "'trace_pipe' entry\n");
3956 entry = debugfs_create_file("buffer_size_kb", 0644, d_tracer,
3957 &global_trace, &tracing_entries_fops);
3959 pr_warning("Could not create debugfs "
3960 "'buffer_size_kb' entry\n");
3962 entry = debugfs_create_file("trace_marker", 0220, d_tracer,
3963 NULL, &tracing_mark_fops);
3965 pr_warning("Could not create debugfs "
3966 "'trace_marker' entry\n");
3968 #ifdef CONFIG_DYNAMIC_FTRACE
3969 entry = debugfs_create_file("dyn_ftrace_total_info", 0444, d_tracer,
3970 &ftrace_update_tot_cnt,
3971 &tracing_dyn_info_fops);
3973 pr_warning("Could not create debugfs "
3974 "'dyn_ftrace_total_info' entry\n");
3976 #ifdef CONFIG_SYSPROF_TRACER
3977 init_tracer_sysprof_debugfs(d_tracer);
3980 for_each_tracing_cpu(cpu)
3981 tracing_init_debugfs_percpu(cpu);
3986 static int trace_panic_handler(struct notifier_block *this,
3987 unsigned long event, void *unused)
3989 if (ftrace_dump_on_oops)
3994 static struct notifier_block trace_panic_notifier = {
3995 .notifier_call = trace_panic_handler,
3997 .priority = 150 /* priority: INT_MAX >= x >= 0 */
4000 static int trace_die_handler(struct notifier_block *self,
4006 if (ftrace_dump_on_oops)
4015 static struct notifier_block trace_die_notifier = {
4016 .notifier_call = trace_die_handler,
4021 * printk is set to max of 1024, we really don't need it that big.
4022 * Nothing should be printing 1000 characters anyway.
4024 #define TRACE_MAX_PRINT 1000
4027 * Define here KERN_TRACE so that we have one place to modify
4028 * it if we decide to change what log level the ftrace dump
4031 #define KERN_TRACE KERN_EMERG
4034 trace_printk_seq(struct trace_seq *s)
4036 /* Probably should print a warning here. */
4040 /* should be zero ended, but we are paranoid. */
4041 s->buffer[s->len] = 0;
4043 printk(KERN_TRACE "%s", s->buffer);
4048 void ftrace_dump(void)
4050 static DEFINE_SPINLOCK(ftrace_dump_lock);
4051 /* use static because iter can be a bit big for the stack */
4052 static struct trace_iterator iter;
4053 static int dump_ran;
4054 unsigned long flags;
4058 spin_lock_irqsave(&ftrace_dump_lock, flags);
4064 /* No turning back! */
4068 for_each_tracing_cpu(cpu) {
4069 atomic_inc(&global_trace.data[cpu]->disabled);
4072 /* don't look at user memory in panic mode */
4073 trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
4075 printk(KERN_TRACE "Dumping ftrace buffer:\n");
4077 /* Simulate the iterator */
4078 iter.tr = &global_trace;
4079 iter.trace = current_trace;
4080 iter.cpu_file = TRACE_PIPE_ALL_CPU;
4083 * We need to stop all tracing on all CPUS to read the
4084 * the next buffer. This is a bit expensive, but is
4085 * not done often. We fill all what we can read,
4086 * and then release the locks again.
4089 while (!trace_empty(&iter)) {
4092 printk(KERN_TRACE "---------------------------------\n");
4096 /* reset all but tr, trace, and overruns */
4097 memset(&iter.seq, 0,
4098 sizeof(struct trace_iterator) -
4099 offsetof(struct trace_iterator, seq));
4100 iter.iter_flags |= TRACE_FILE_LAT_FMT;
4103 if (find_next_entry_inc(&iter) != NULL) {
4104 print_trace_line(&iter);
4105 trace_consume(&iter);
4108 trace_printk_seq(&iter.seq);
4112 printk(KERN_TRACE " (ftrace buffer empty)\n");
4114 printk(KERN_TRACE "---------------------------------\n");
4117 spin_unlock_irqrestore(&ftrace_dump_lock, flags);
4120 __init static int tracer_alloc_buffers(void)
4122 struct trace_array_cpu *data;
4127 if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
4130 if (!alloc_cpumask_var(&tracing_cpumask, GFP_KERNEL))
4131 goto out_free_buffer_mask;
4133 if (!alloc_cpumask_var(&tracing_reader_cpumask, GFP_KERNEL))
4134 goto out_free_tracing_cpumask;
4136 /* To save memory, keep the ring buffer size to its minimum */
4137 if (ring_buffer_expanded)
4138 ring_buf_size = trace_buf_size;
4142 cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
4143 cpumask_copy(tracing_cpumask, cpu_all_mask);
4144 cpumask_clear(tracing_reader_cpumask);
4146 /* TODO: make the number of buffers hot pluggable with CPUS */
4147 global_trace.buffer = ring_buffer_alloc(ring_buf_size,
4148 TRACE_BUFFER_FLAGS);
4149 if (!global_trace.buffer) {
4150 printk(KERN_ERR "tracer: failed to allocate ring buffer!\n");
4152 goto out_free_cpumask;
4154 global_trace.entries = ring_buffer_size(global_trace.buffer);
4157 #ifdef CONFIG_TRACER_MAX_TRACE
4158 max_tr.buffer = ring_buffer_alloc(ring_buf_size,
4159 TRACE_BUFFER_FLAGS);
4160 if (!max_tr.buffer) {
4161 printk(KERN_ERR "tracer: failed to allocate max ring buffer!\n");
4163 ring_buffer_free(global_trace.buffer);
4164 goto out_free_cpumask;
4166 max_tr.entries = ring_buffer_size(max_tr.buffer);
4167 WARN_ON(max_tr.entries != global_trace.entries);
4170 /* Allocate the first page for all buffers */
4171 for_each_tracing_cpu(i) {
4172 data = global_trace.data[i] = &per_cpu(global_trace_cpu, i);
4173 max_tr.data[i] = &per_cpu(max_data, i);
4176 trace_init_cmdlines();
4178 register_tracer(&nop_trace);
4179 current_trace = &nop_trace;
4180 #ifdef CONFIG_BOOT_TRACER
4181 register_tracer(&boot_tracer);
4183 /* All seems OK, enable tracing */
4184 tracing_disabled = 0;
4186 atomic_notifier_chain_register(&panic_notifier_list,
4187 &trace_panic_notifier);
4189 register_die_notifier(&trace_die_notifier);
4194 free_cpumask_var(tracing_reader_cpumask);
4195 out_free_tracing_cpumask:
4196 free_cpumask_var(tracing_cpumask);
4197 out_free_buffer_mask:
4198 free_cpumask_var(tracing_buffer_mask);
4203 __init static int clear_boot_tracer(void)
4206 * The default tracer at boot buffer is an init section.
4207 * This function is called in lateinit. If we did not
4208 * find the boot tracer, then clear it out, to prevent
4209 * later registration from accessing the buffer that is
4210 * about to be freed.
4212 if (!default_bootup_tracer)
4215 printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n",
4216 default_bootup_tracer);
4217 default_bootup_tracer = NULL;
4222 early_initcall(tracer_alloc_buffers);
4223 fs_initcall(tracer_init_debugfs);
4224 late_initcall(clear_boot_tracer);