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/utsrelease.h>
15 #include <linux/kallsyms.h>
16 #include <linux/seq_file.h>
17 #include <linux/notifier.h>
18 #include <linux/debugfs.h>
19 #include <linux/pagemap.h>
20 #include <linux/hardirq.h>
21 #include <linux/linkage.h>
22 #include <linux/uaccess.h>
23 #include <linux/ftrace.h>
24 #include <linux/module.h>
25 #include <linux/percpu.h>
26 #include <linux/kdebug.h>
27 #include <linux/ctype.h>
28 #include <linux/init.h>
29 #include <linux/poll.h>
30 #include <linux/gfp.h>
32 #include <linux/kprobes.h>
33 #include <linux/writeback.h>
35 #include <linux/stacktrace.h>
36 #include <linux/ring_buffer.h>
37 #include <linux/irqflags.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 * We need to change this state when a selftest is running.
49 * A selftest will lurk into the ring-buffer to count the
50 * entries inserted during the selftest although some concurrent
51 * insertions into the ring-buffer such as ftrace_printk could occurred
52 * at the same time, giving false positive or negative results.
54 static bool __read_mostly tracing_selftest_running;
56 /* For tracers that don't implement custom flags */
57 static struct tracer_opt dummy_tracer_opt[] = {
61 static struct tracer_flags dummy_tracer_flags = {
63 .opts = dummy_tracer_opt
66 static int dummy_set_flag(u32 old_flags, u32 bit, int set)
72 * Kill all tracing for good (never come back).
73 * It is initialized to 1 but will turn to zero if the initialization
74 * of the tracer is successful. But that is the only place that sets
77 int tracing_disabled = 1;
79 static DEFINE_PER_CPU(local_t, ftrace_cpu_disabled);
81 static inline void ftrace_disable_cpu(void)
84 local_inc(&__get_cpu_var(ftrace_cpu_disabled));
87 static inline void ftrace_enable_cpu(void)
89 local_dec(&__get_cpu_var(ftrace_cpu_disabled));
93 static cpumask_var_t __read_mostly tracing_buffer_mask;
95 #define for_each_tracing_cpu(cpu) \
96 for_each_cpu(cpu, tracing_buffer_mask)
99 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
101 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
102 * is set, then ftrace_dump is called. This will output the contents
103 * of the ftrace buffers to the console. This is very useful for
104 * capturing traces that lead to crashes and outputing it to a
107 * It is default off, but you can enable it with either specifying
108 * "ftrace_dump_on_oops" in the kernel command line, or setting
109 * /proc/sys/kernel/ftrace_dump_on_oops to true.
111 int ftrace_dump_on_oops;
113 static int tracing_set_tracer(char *buf);
115 static int __init set_ftrace(char *str)
117 tracing_set_tracer(str);
120 __setup("ftrace", set_ftrace);
122 static int __init set_ftrace_dump_on_oops(char *str)
124 ftrace_dump_on_oops = 1;
127 __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
130 ns2usecs(cycle_t nsec)
137 cycle_t ftrace_now(int cpu)
139 u64 ts = ring_buffer_time_stamp(cpu);
140 ring_buffer_normalize_time_stamp(cpu, &ts);
145 * The global_trace is the descriptor that holds the tracing
146 * buffers for the live tracing. For each CPU, it contains
147 * a link list of pages that will store trace entries. The
148 * page descriptor of the pages in the memory is used to hold
149 * the link list by linking the lru item in the page descriptor
150 * to each of the pages in the buffer per CPU.
152 * For each active CPU there is a data field that holds the
153 * pages for the buffer for that CPU. Each CPU has the same number
154 * of pages allocated for its buffer.
156 static struct trace_array global_trace;
158 static DEFINE_PER_CPU(struct trace_array_cpu, global_trace_cpu);
161 * The max_tr is used to snapshot the global_trace when a maximum
162 * latency is reached. Some tracers will use this to store a maximum
163 * trace while it continues examining live traces.
165 * The buffers for the max_tr are set up the same as the global_trace.
166 * When a snapshot is taken, the link list of the max_tr is swapped
167 * with the link list of the global_trace and the buffers are reset for
168 * the global_trace so the tracing can continue.
170 static struct trace_array max_tr;
172 static DEFINE_PER_CPU(struct trace_array_cpu, max_data);
174 /* tracer_enabled is used to toggle activation of a tracer */
175 static int tracer_enabled = 1;
178 * tracing_is_enabled - return tracer_enabled status
180 * This function is used by other tracers to know the status
181 * of the tracer_enabled flag. Tracers may use this function
182 * to know if it should enable their features when starting
183 * up. See irqsoff tracer for an example (start_irqsoff_tracer).
185 int tracing_is_enabled(void)
187 return tracer_enabled;
191 * trace_buf_size is the size in bytes that is allocated
192 * for a buffer. Note, the number of bytes is always rounded
195 * This number is purposely set to a low number of 16384.
196 * If the dump on oops happens, it will be much appreciated
197 * to not have to wait for all that output. Anyway this can be
198 * boot time and run time configurable.
200 #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
202 static unsigned long trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
204 /* trace_types holds a link list of available tracers. */
205 static struct tracer *trace_types __read_mostly;
207 /* current_trace points to the tracer that is currently active */
208 static struct tracer *current_trace __read_mostly;
211 * max_tracer_type_len is used to simplify the allocating of
212 * buffers to read userspace tracer names. We keep track of
213 * the longest tracer name registered.
215 static int max_tracer_type_len;
218 * trace_types_lock is used to protect the trace_types list.
219 * This lock is also used to keep user access serialized.
220 * Accesses from userspace will grab this lock while userspace
221 * activities happen inside the kernel.
223 static DEFINE_MUTEX(trace_types_lock);
225 /* trace_wait is a waitqueue for tasks blocked on trace_poll */
226 static DECLARE_WAIT_QUEUE_HEAD(trace_wait);
228 /* trace_flags holds trace_options default values */
229 unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK |
230 TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO;
233 * trace_wake_up - wake up tasks waiting for trace input
235 * Simply wakes up any task that is blocked on the trace_wait
236 * queue. These is used with trace_poll for tasks polling the trace.
238 void trace_wake_up(void)
241 * The runqueue_is_locked() can fail, but this is the best we
244 if (!(trace_flags & TRACE_ITER_BLOCK) && !runqueue_is_locked())
245 wake_up(&trace_wait);
248 static int __init set_buf_size(char *str)
250 unsigned long buf_size;
255 ret = strict_strtoul(str, 0, &buf_size);
256 /* nr_entries can not be zero */
257 if (ret < 0 || buf_size == 0)
259 trace_buf_size = buf_size;
262 __setup("trace_buf_size=", set_buf_size);
264 unsigned long nsecs_to_usecs(unsigned long nsecs)
269 /* These must match the bit postions in trace_iterator_flags */
270 static const char *trace_options[] = {
293 * ftrace_max_lock is used to protect the swapping of buffers
294 * when taking a max snapshot. The buffers themselves are
295 * protected by per_cpu spinlocks. But the action of the swap
296 * needs its own lock.
298 * This is defined as a raw_spinlock_t in order to help
299 * with performance when lockdep debugging is enabled.
301 static raw_spinlock_t ftrace_max_lock =
302 (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
305 * Copy the new maximum trace into the separate maximum-trace
306 * structure. (this way the maximum trace is permanently saved,
307 * for later retrieval via /debugfs/tracing/latency_trace)
310 __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
312 struct trace_array_cpu *data = tr->data[cpu];
315 max_tr.time_start = data->preempt_timestamp;
317 data = max_tr.data[cpu];
318 data->saved_latency = tracing_max_latency;
320 memcpy(data->comm, tsk->comm, TASK_COMM_LEN);
321 data->pid = tsk->pid;
322 data->uid = task_uid(tsk);
323 data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
324 data->policy = tsk->policy;
325 data->rt_priority = tsk->rt_priority;
327 /* record this tasks comm */
328 tracing_record_cmdline(current);
332 trace_seq_reset(struct trace_seq *s)
338 ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
343 if (s->len <= s->readpos)
346 len = s->len - s->readpos;
349 ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
358 trace_print_seq(struct seq_file *m, struct trace_seq *s)
360 int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len;
363 seq_puts(m, s->buffer);
369 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
371 * @tsk: the task with the latency
372 * @cpu: The cpu that initiated the trace.
374 * Flip the buffers between the @tr and the max_tr and record information
375 * about which task was the cause of this latency.
378 update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
380 struct ring_buffer *buf = tr->buffer;
382 WARN_ON_ONCE(!irqs_disabled());
383 __raw_spin_lock(&ftrace_max_lock);
385 tr->buffer = max_tr.buffer;
388 ftrace_disable_cpu();
389 ring_buffer_reset(tr->buffer);
392 __update_max_tr(tr, tsk, cpu);
393 __raw_spin_unlock(&ftrace_max_lock);
397 * update_max_tr_single - only copy one trace over, and reset the rest
399 * @tsk - task with the latency
400 * @cpu - the cpu of the buffer to copy.
402 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
405 update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
409 WARN_ON_ONCE(!irqs_disabled());
410 __raw_spin_lock(&ftrace_max_lock);
412 ftrace_disable_cpu();
414 ring_buffer_reset(max_tr.buffer);
415 ret = ring_buffer_swap_cpu(max_tr.buffer, tr->buffer, cpu);
419 WARN_ON_ONCE(ret && ret != -EAGAIN);
421 __update_max_tr(tr, tsk, cpu);
422 __raw_spin_unlock(&ftrace_max_lock);
426 * register_tracer - register a tracer with the ftrace system.
427 * @type - the plugin for the tracer
429 * Register a new plugin tracer.
431 int register_tracer(struct tracer *type)
438 pr_info("Tracer must have a name\n");
443 * When this gets called we hold the BKL which means that
444 * preemption is disabled. Various trace selftests however
445 * need to disable and enable preemption for successful tests.
446 * So we drop the BKL here and grab it after the tests again.
449 mutex_lock(&trace_types_lock);
451 tracing_selftest_running = true;
453 for (t = trace_types; t; t = t->next) {
454 if (strcmp(type->name, t->name) == 0) {
456 pr_info("Trace %s already registered\n",
464 type->set_flag = &dummy_set_flag;
466 type->flags = &dummy_tracer_flags;
468 if (!type->flags->opts)
469 type->flags->opts = dummy_tracer_opt;
471 #ifdef CONFIG_FTRACE_STARTUP_TEST
472 if (type->selftest) {
473 struct tracer *saved_tracer = current_trace;
474 struct trace_array *tr = &global_trace;
478 * Run a selftest on this tracer.
479 * Here we reset the trace buffer, and set the current
480 * tracer to be this tracer. The tracer can then run some
481 * internal tracing to verify that everything is in order.
482 * If we fail, we do not register this tracer.
484 for_each_tracing_cpu(i)
485 tracing_reset(tr, i);
487 current_trace = type;
488 /* the test is responsible for initializing and enabling */
489 pr_info("Testing tracer %s: ", type->name);
490 ret = type->selftest(type, tr);
491 /* the test is responsible for resetting too */
492 current_trace = saved_tracer;
494 printk(KERN_CONT "FAILED!\n");
497 /* Only reset on passing, to avoid touching corrupted buffers */
498 for_each_tracing_cpu(i)
499 tracing_reset(tr, i);
501 printk(KERN_CONT "PASSED\n");
505 type->next = trace_types;
507 len = strlen(type->name);
508 if (len > max_tracer_type_len)
509 max_tracer_type_len = len;
512 tracing_selftest_running = false;
513 mutex_unlock(&trace_types_lock);
519 void unregister_tracer(struct tracer *type)
524 mutex_lock(&trace_types_lock);
525 for (t = &trace_types; *t; t = &(*t)->next) {
529 pr_info("Trace %s not registered\n", type->name);
534 if (strlen(type->name) != max_tracer_type_len)
537 max_tracer_type_len = 0;
538 for (t = &trace_types; *t; t = &(*t)->next) {
539 len = strlen((*t)->name);
540 if (len > max_tracer_type_len)
541 max_tracer_type_len = len;
544 mutex_unlock(&trace_types_lock);
547 void tracing_reset(struct trace_array *tr, int cpu)
549 ftrace_disable_cpu();
550 ring_buffer_reset_cpu(tr->buffer, cpu);
554 void tracing_reset_online_cpus(struct trace_array *tr)
558 tr->time_start = ftrace_now(tr->cpu);
560 for_each_online_cpu(cpu)
561 tracing_reset(tr, cpu);
564 #define SAVED_CMDLINES 128
565 static unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
566 static unsigned map_cmdline_to_pid[SAVED_CMDLINES];
567 static char saved_cmdlines[SAVED_CMDLINES][TASK_COMM_LEN];
568 static int cmdline_idx;
569 static DEFINE_SPINLOCK(trace_cmdline_lock);
571 /* temporary disable recording */
572 atomic_t trace_record_cmdline_disabled __read_mostly;
574 static void trace_init_cmdlines(void)
576 memset(&map_pid_to_cmdline, -1, sizeof(map_pid_to_cmdline));
577 memset(&map_cmdline_to_pid, -1, sizeof(map_cmdline_to_pid));
581 static int trace_stop_count;
582 static DEFINE_SPINLOCK(tracing_start_lock);
585 * ftrace_off_permanent - disable all ftrace code permanently
587 * This should only be called when a serious anomally has
588 * been detected. This will turn off the function tracing,
589 * ring buffers, and other tracing utilites. It takes no
590 * locks and can be called from any context.
592 void ftrace_off_permanent(void)
594 tracing_disabled = 1;
596 tracing_off_permanent();
600 * tracing_start - quick start of the tracer
602 * If tracing is enabled but was stopped by tracing_stop,
603 * this will start the tracer back up.
605 void tracing_start(void)
607 struct ring_buffer *buffer;
610 if (tracing_disabled)
613 spin_lock_irqsave(&tracing_start_lock, flags);
614 if (--trace_stop_count) {
615 if (trace_stop_count < 0) {
616 /* Someone screwed up their debugging */
618 trace_stop_count = 0;
624 buffer = global_trace.buffer;
626 ring_buffer_record_enable(buffer);
628 buffer = max_tr.buffer;
630 ring_buffer_record_enable(buffer);
634 spin_unlock_irqrestore(&tracing_start_lock, flags);
638 * tracing_stop - quick stop of the tracer
640 * Light weight way to stop tracing. Use in conjunction with
643 void tracing_stop(void)
645 struct ring_buffer *buffer;
649 spin_lock_irqsave(&tracing_start_lock, flags);
650 if (trace_stop_count++)
653 buffer = global_trace.buffer;
655 ring_buffer_record_disable(buffer);
657 buffer = max_tr.buffer;
659 ring_buffer_record_disable(buffer);
662 spin_unlock_irqrestore(&tracing_start_lock, flags);
665 void trace_stop_cmdline_recording(void);
667 static void trace_save_cmdline(struct task_struct *tsk)
672 if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT))
676 * It's not the end of the world if we don't get
677 * the lock, but we also don't want to spin
678 * nor do we want to disable interrupts,
679 * so if we miss here, then better luck next time.
681 if (!spin_trylock(&trace_cmdline_lock))
684 idx = map_pid_to_cmdline[tsk->pid];
685 if (idx >= SAVED_CMDLINES) {
686 idx = (cmdline_idx + 1) % SAVED_CMDLINES;
688 map = map_cmdline_to_pid[idx];
689 if (map <= PID_MAX_DEFAULT)
690 map_pid_to_cmdline[map] = (unsigned)-1;
692 map_pid_to_cmdline[tsk->pid] = idx;
697 memcpy(&saved_cmdlines[idx], tsk->comm, TASK_COMM_LEN);
699 spin_unlock(&trace_cmdline_lock);
702 char *trace_find_cmdline(int pid)
704 char *cmdline = "<...>";
710 if (pid > PID_MAX_DEFAULT)
713 map = map_pid_to_cmdline[pid];
714 if (map >= SAVED_CMDLINES)
717 cmdline = saved_cmdlines[map];
723 void tracing_record_cmdline(struct task_struct *tsk)
725 if (atomic_read(&trace_record_cmdline_disabled))
728 trace_save_cmdline(tsk);
732 tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
735 struct task_struct *tsk = current;
737 entry->preempt_count = pc & 0xff;
738 entry->pid = (tsk) ? tsk->pid : 0;
739 entry->tgid = (tsk) ? tsk->tgid : 0;
741 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
742 (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
744 TRACE_FLAG_IRQS_NOSUPPORT |
746 ((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
747 ((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
748 (need_resched() ? TRACE_FLAG_NEED_RESCHED : 0);
752 trace_function(struct trace_array *tr, struct trace_array_cpu *data,
753 unsigned long ip, unsigned long parent_ip, unsigned long flags,
756 struct ring_buffer_event *event;
757 struct ftrace_entry *entry;
758 unsigned long irq_flags;
760 /* If we are reading the ring buffer, don't trace */
761 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
764 event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
768 entry = ring_buffer_event_data(event);
769 tracing_generic_entry_update(&entry->ent, flags, pc);
770 entry->ent.type = TRACE_FN;
772 entry->parent_ip = parent_ip;
773 ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
776 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
777 static void __trace_graph_entry(struct trace_array *tr,
778 struct trace_array_cpu *data,
779 struct ftrace_graph_ent *trace,
783 struct ring_buffer_event *event;
784 struct ftrace_graph_ent_entry *entry;
785 unsigned long irq_flags;
787 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
790 event = ring_buffer_lock_reserve(global_trace.buffer, sizeof(*entry),
794 entry = ring_buffer_event_data(event);
795 tracing_generic_entry_update(&entry->ent, flags, pc);
796 entry->ent.type = TRACE_GRAPH_ENT;
797 entry->graph_ent = *trace;
798 ring_buffer_unlock_commit(global_trace.buffer, event, irq_flags);
801 static void __trace_graph_return(struct trace_array *tr,
802 struct trace_array_cpu *data,
803 struct ftrace_graph_ret *trace,
807 struct ring_buffer_event *event;
808 struct ftrace_graph_ret_entry *entry;
809 unsigned long irq_flags;
811 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
814 event = ring_buffer_lock_reserve(global_trace.buffer, sizeof(*entry),
818 entry = ring_buffer_event_data(event);
819 tracing_generic_entry_update(&entry->ent, flags, pc);
820 entry->ent.type = TRACE_GRAPH_RET;
822 ring_buffer_unlock_commit(global_trace.buffer, event, irq_flags);
827 ftrace(struct trace_array *tr, struct trace_array_cpu *data,
828 unsigned long ip, unsigned long parent_ip, unsigned long flags,
831 if (likely(!atomic_read(&data->disabled)))
832 trace_function(tr, data, ip, parent_ip, flags, pc);
835 static void __ftrace_trace_stack(struct trace_array *tr,
836 struct trace_array_cpu *data,
840 #ifdef CONFIG_STACKTRACE
841 struct ring_buffer_event *event;
842 struct stack_entry *entry;
843 struct stack_trace trace;
844 unsigned long irq_flags;
846 event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
850 entry = ring_buffer_event_data(event);
851 tracing_generic_entry_update(&entry->ent, flags, pc);
852 entry->ent.type = TRACE_STACK;
854 memset(&entry->caller, 0, sizeof(entry->caller));
856 trace.nr_entries = 0;
857 trace.max_entries = FTRACE_STACK_ENTRIES;
859 trace.entries = entry->caller;
861 save_stack_trace(&trace);
862 ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
866 static void ftrace_trace_stack(struct trace_array *tr,
867 struct trace_array_cpu *data,
871 if (!(trace_flags & TRACE_ITER_STACKTRACE))
874 __ftrace_trace_stack(tr, data, flags, skip, pc);
877 void __trace_stack(struct trace_array *tr,
878 struct trace_array_cpu *data,
882 __ftrace_trace_stack(tr, data, flags, skip, pc);
885 static void ftrace_trace_userstack(struct trace_array *tr,
886 struct trace_array_cpu *data,
887 unsigned long flags, int pc)
889 #ifdef CONFIG_STACKTRACE
890 struct ring_buffer_event *event;
891 struct userstack_entry *entry;
892 struct stack_trace trace;
893 unsigned long irq_flags;
895 if (!(trace_flags & TRACE_ITER_USERSTACKTRACE))
898 event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
902 entry = ring_buffer_event_data(event);
903 tracing_generic_entry_update(&entry->ent, flags, pc);
904 entry->ent.type = TRACE_USER_STACK;
906 memset(&entry->caller, 0, sizeof(entry->caller));
908 trace.nr_entries = 0;
909 trace.max_entries = FTRACE_STACK_ENTRIES;
911 trace.entries = entry->caller;
913 save_stack_trace_user(&trace);
914 ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
918 void __trace_userstack(struct trace_array *tr,
919 struct trace_array_cpu *data,
922 ftrace_trace_userstack(tr, data, flags, preempt_count());
926 ftrace_trace_special(void *__tr, void *__data,
927 unsigned long arg1, unsigned long arg2, unsigned long arg3,
930 struct ring_buffer_event *event;
931 struct trace_array_cpu *data = __data;
932 struct trace_array *tr = __tr;
933 struct special_entry *entry;
934 unsigned long irq_flags;
936 event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
940 entry = ring_buffer_event_data(event);
941 tracing_generic_entry_update(&entry->ent, 0, pc);
942 entry->ent.type = TRACE_SPECIAL;
946 ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
947 ftrace_trace_stack(tr, data, irq_flags, 4, pc);
948 ftrace_trace_userstack(tr, data, irq_flags, pc);
954 __trace_special(void *__tr, void *__data,
955 unsigned long arg1, unsigned long arg2, unsigned long arg3)
957 ftrace_trace_special(__tr, __data, arg1, arg2, arg3, preempt_count());
961 tracing_sched_switch_trace(struct trace_array *tr,
962 struct trace_array_cpu *data,
963 struct task_struct *prev,
964 struct task_struct *next,
965 unsigned long flags, int pc)
967 struct ring_buffer_event *event;
968 struct ctx_switch_entry *entry;
969 unsigned long irq_flags;
971 event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
975 entry = ring_buffer_event_data(event);
976 tracing_generic_entry_update(&entry->ent, flags, pc);
977 entry->ent.type = TRACE_CTX;
978 entry->prev_pid = prev->pid;
979 entry->prev_prio = prev->prio;
980 entry->prev_state = prev->state;
981 entry->next_pid = next->pid;
982 entry->next_prio = next->prio;
983 entry->next_state = next->state;
984 entry->next_cpu = task_cpu(next);
985 ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
986 ftrace_trace_stack(tr, data, flags, 5, pc);
987 ftrace_trace_userstack(tr, data, flags, pc);
991 tracing_sched_wakeup_trace(struct trace_array *tr,
992 struct trace_array_cpu *data,
993 struct task_struct *wakee,
994 struct task_struct *curr,
995 unsigned long flags, int pc)
997 struct ring_buffer_event *event;
998 struct ctx_switch_entry *entry;
999 unsigned long irq_flags;
1001 event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
1005 entry = ring_buffer_event_data(event);
1006 tracing_generic_entry_update(&entry->ent, flags, pc);
1007 entry->ent.type = TRACE_WAKE;
1008 entry->prev_pid = curr->pid;
1009 entry->prev_prio = curr->prio;
1010 entry->prev_state = curr->state;
1011 entry->next_pid = wakee->pid;
1012 entry->next_prio = wakee->prio;
1013 entry->next_state = wakee->state;
1014 entry->next_cpu = task_cpu(wakee);
1015 ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
1016 ftrace_trace_stack(tr, data, flags, 6, pc);
1017 ftrace_trace_userstack(tr, data, flags, pc);
1023 ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3)
1025 struct trace_array *tr = &global_trace;
1026 struct trace_array_cpu *data;
1027 unsigned long flags;
1031 if (tracing_disabled)
1034 pc = preempt_count();
1035 local_irq_save(flags);
1036 cpu = raw_smp_processor_id();
1037 data = tr->data[cpu];
1039 if (likely(atomic_inc_return(&data->disabled) == 1))
1040 ftrace_trace_special(tr, data, arg1, arg2, arg3, pc);
1042 atomic_dec(&data->disabled);
1043 local_irq_restore(flags);
1046 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1047 int trace_graph_entry(struct ftrace_graph_ent *trace)
1049 struct trace_array *tr = &global_trace;
1050 struct trace_array_cpu *data;
1051 unsigned long flags;
1056 if (!ftrace_trace_task(current))
1059 if (!ftrace_graph_addr(trace->func))
1062 local_irq_save(flags);
1063 cpu = raw_smp_processor_id();
1064 data = tr->data[cpu];
1065 disabled = atomic_inc_return(&data->disabled);
1066 if (likely(disabled == 1)) {
1067 pc = preempt_count();
1068 __trace_graph_entry(tr, data, trace, flags, pc);
1070 /* Only do the atomic if it is not already set */
1071 if (!test_tsk_trace_graph(current))
1072 set_tsk_trace_graph(current);
1073 atomic_dec(&data->disabled);
1074 local_irq_restore(flags);
1079 void trace_graph_return(struct ftrace_graph_ret *trace)
1081 struct trace_array *tr = &global_trace;
1082 struct trace_array_cpu *data;
1083 unsigned long flags;
1088 local_irq_save(flags);
1089 cpu = raw_smp_processor_id();
1090 data = tr->data[cpu];
1091 disabled = atomic_inc_return(&data->disabled);
1092 if (likely(disabled == 1)) {
1093 pc = preempt_count();
1094 __trace_graph_return(tr, data, trace, flags, pc);
1097 clear_tsk_trace_graph(current);
1098 atomic_dec(&data->disabled);
1099 local_irq_restore(flags);
1101 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
1103 enum trace_file_type {
1104 TRACE_FILE_LAT_FMT = 1,
1105 TRACE_FILE_ANNOTATE = 2,
1108 static void trace_iterator_increment(struct trace_iterator *iter)
1110 /* Don't allow ftrace to trace into the ring buffers */
1111 ftrace_disable_cpu();
1114 if (iter->buffer_iter[iter->cpu])
1115 ring_buffer_read(iter->buffer_iter[iter->cpu], NULL);
1117 ftrace_enable_cpu();
1120 static struct trace_entry *
1121 peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts)
1123 struct ring_buffer_event *event;
1124 struct ring_buffer_iter *buf_iter = iter->buffer_iter[cpu];
1126 /* Don't allow ftrace to trace into the ring buffers */
1127 ftrace_disable_cpu();
1130 event = ring_buffer_iter_peek(buf_iter, ts);
1132 event = ring_buffer_peek(iter->tr->buffer, cpu, ts);
1134 ftrace_enable_cpu();
1136 return event ? ring_buffer_event_data(event) : NULL;
1139 static struct trace_entry *
1140 __find_next_entry(struct trace_iterator *iter, int *ent_cpu, u64 *ent_ts)
1142 struct ring_buffer *buffer = iter->tr->buffer;
1143 struct trace_entry *ent, *next = NULL;
1144 u64 next_ts = 0, ts;
1148 for_each_tracing_cpu(cpu) {
1150 if (ring_buffer_empty_cpu(buffer, cpu))
1153 ent = peek_next_entry(iter, cpu, &ts);
1156 * Pick the entry with the smallest timestamp:
1158 if (ent && (!next || ts < next_ts)) {
1166 *ent_cpu = next_cpu;
1174 /* Find the next real entry, without updating the iterator itself */
1175 struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
1176 int *ent_cpu, u64 *ent_ts)
1178 return __find_next_entry(iter, ent_cpu, ent_ts);
1181 /* Find the next real entry, and increment the iterator to the next entry */
1182 static void *find_next_entry_inc(struct trace_iterator *iter)
1184 iter->ent = __find_next_entry(iter, &iter->cpu, &iter->ts);
1187 trace_iterator_increment(iter);
1189 return iter->ent ? iter : NULL;
1192 static void trace_consume(struct trace_iterator *iter)
1194 /* Don't allow ftrace to trace into the ring buffers */
1195 ftrace_disable_cpu();
1196 ring_buffer_consume(iter->tr->buffer, iter->cpu, &iter->ts);
1197 ftrace_enable_cpu();
1200 static void *s_next(struct seq_file *m, void *v, loff_t *pos)
1202 struct trace_iterator *iter = m->private;
1208 /* can't go backwards */
1213 ent = find_next_entry_inc(iter);
1217 while (ent && iter->idx < i)
1218 ent = find_next_entry_inc(iter);
1225 static void *s_start(struct seq_file *m, loff_t *pos)
1227 struct trace_iterator *iter = m->private;
1232 mutex_lock(&trace_types_lock);
1234 if (!current_trace || current_trace != iter->trace) {
1235 mutex_unlock(&trace_types_lock);
1239 atomic_inc(&trace_record_cmdline_disabled);
1241 if (*pos != iter->pos) {
1246 ftrace_disable_cpu();
1248 for_each_tracing_cpu(cpu) {
1249 ring_buffer_iter_reset(iter->buffer_iter[cpu]);
1252 ftrace_enable_cpu();
1254 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
1259 p = s_next(m, p, &l);
1265 static void s_stop(struct seq_file *m, void *p)
1267 atomic_dec(&trace_record_cmdline_disabled);
1268 mutex_unlock(&trace_types_lock);
1271 static void print_lat_help_header(struct seq_file *m)
1273 seq_puts(m, "# _------=> CPU# \n");
1274 seq_puts(m, "# / _-----=> irqs-off \n");
1275 seq_puts(m, "# | / _----=> need-resched \n");
1276 seq_puts(m, "# || / _---=> hardirq/softirq \n");
1277 seq_puts(m, "# ||| / _--=> preempt-depth \n");
1278 seq_puts(m, "# |||| / \n");
1279 seq_puts(m, "# ||||| delay \n");
1280 seq_puts(m, "# cmd pid ||||| time | caller \n");
1281 seq_puts(m, "# \\ / ||||| \\ | / \n");
1284 static void print_func_help_header(struct seq_file *m)
1286 seq_puts(m, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
1287 seq_puts(m, "# | | | | |\n");
1292 print_trace_header(struct seq_file *m, struct trace_iterator *iter)
1294 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1295 struct trace_array *tr = iter->tr;
1296 struct trace_array_cpu *data = tr->data[tr->cpu];
1297 struct tracer *type = current_trace;
1298 unsigned long total;
1299 unsigned long entries;
1300 const char *name = "preemption";
1305 entries = ring_buffer_entries(iter->tr->buffer);
1307 ring_buffer_overruns(iter->tr->buffer);
1309 seq_printf(m, "%s latency trace v1.1.5 on %s\n",
1311 seq_puts(m, "-----------------------------------"
1312 "---------------------------------\n");
1313 seq_printf(m, " latency: %lu us, #%lu/%lu, CPU#%d |"
1314 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
1315 nsecs_to_usecs(data->saved_latency),
1319 #if defined(CONFIG_PREEMPT_NONE)
1321 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
1323 #elif defined(CONFIG_PREEMPT)
1328 /* These are reserved for later use */
1331 seq_printf(m, " #P:%d)\n", num_online_cpus());
1335 seq_puts(m, " -----------------\n");
1336 seq_printf(m, " | task: %.16s-%d "
1337 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
1338 data->comm, data->pid, data->uid, data->nice,
1339 data->policy, data->rt_priority);
1340 seq_puts(m, " -----------------\n");
1342 if (data->critical_start) {
1343 seq_puts(m, " => started at: ");
1344 seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
1345 trace_print_seq(m, &iter->seq);
1346 seq_puts(m, "\n => ended at: ");
1347 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
1348 trace_print_seq(m, &iter->seq);
1355 static void test_cpu_buff_start(struct trace_iterator *iter)
1357 struct trace_seq *s = &iter->seq;
1359 if (!(trace_flags & TRACE_ITER_ANNOTATE))
1362 if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
1365 if (cpumask_test_cpu(iter->cpu, iter->started))
1368 cpumask_set_cpu(iter->cpu, iter->started);
1369 trace_seq_printf(s, "##### CPU %u buffer started ####\n", iter->cpu);
1372 static enum print_line_t print_lat_fmt(struct trace_iterator *iter)
1374 struct trace_seq *s = &iter->seq;
1375 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1376 struct trace_event *event;
1377 struct trace_entry *entry = iter->ent;
1380 test_cpu_buff_start(iter);
1382 event = ftrace_find_event(entry->type);
1384 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1385 ret = trace_print_lat_context(iter);
1390 if (event && event->latency_trace) {
1391 ret = event->latency_trace(s, entry, sym_flags);
1394 return TRACE_TYPE_HANDLED;
1397 trace_seq_printf(s, "Unknown type %d\n", entry->type);
1398 return TRACE_TYPE_HANDLED;
1401 static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
1403 struct trace_seq *s = &iter->seq;
1404 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1405 struct trace_entry *entry;
1406 struct trace_event *event;
1411 test_cpu_buff_start(iter);
1413 event = ftrace_find_event(entry->type);
1415 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1416 ret = trace_print_context(iter);
1421 if (event && event->trace) {
1422 ret = event->trace(s, entry, sym_flags);
1425 return TRACE_TYPE_HANDLED;
1427 ret = trace_seq_printf(s, "Unknown type %d\n", entry->type);
1429 return TRACE_TYPE_PARTIAL_LINE;
1431 return TRACE_TYPE_HANDLED;
1434 static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
1436 struct trace_seq *s = &iter->seq;
1437 struct trace_entry *entry;
1438 struct trace_event *event;
1443 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1444 ret = trace_seq_printf(s, "%d %d %llu ",
1445 entry->pid, iter->cpu, iter->ts);
1447 return TRACE_TYPE_PARTIAL_LINE;
1450 event = ftrace_find_event(entry->type);
1451 if (event && event->raw) {
1452 ret = event->raw(s, entry, 0);
1455 return TRACE_TYPE_HANDLED;
1457 ret = trace_seq_printf(s, "%d ?\n", entry->type);
1459 return TRACE_TYPE_PARTIAL_LINE;
1461 return TRACE_TYPE_HANDLED;
1464 static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
1466 struct trace_seq *s = &iter->seq;
1467 unsigned char newline = '\n';
1468 struct trace_entry *entry;
1469 struct trace_event *event;
1473 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1474 SEQ_PUT_HEX_FIELD_RET(s, entry->pid);
1475 SEQ_PUT_HEX_FIELD_RET(s, iter->cpu);
1476 SEQ_PUT_HEX_FIELD_RET(s, iter->ts);
1479 event = ftrace_find_event(entry->type);
1480 if (event && event->hex)
1481 event->hex(s, entry, 0);
1483 SEQ_PUT_FIELD_RET(s, newline);
1485 return TRACE_TYPE_HANDLED;
1488 static enum print_line_t print_printk_msg_only(struct trace_iterator *iter)
1490 struct trace_seq *s = &iter->seq;
1491 struct trace_entry *entry = iter->ent;
1492 struct print_entry *field;
1495 trace_assign_type(field, entry);
1497 ret = trace_seq_printf(s, "%s", field->buf);
1499 return TRACE_TYPE_PARTIAL_LINE;
1501 return TRACE_TYPE_HANDLED;
1504 static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
1506 struct trace_seq *s = &iter->seq;
1507 struct trace_entry *entry;
1508 struct trace_event *event;
1512 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1513 SEQ_PUT_FIELD_RET(s, entry->pid);
1514 SEQ_PUT_FIELD_RET(s, entry->cpu);
1515 SEQ_PUT_FIELD_RET(s, iter->ts);
1518 event = ftrace_find_event(entry->type);
1519 if (event && event->binary)
1520 event->binary(s, entry, 0);
1522 return TRACE_TYPE_HANDLED;
1525 static int trace_empty(struct trace_iterator *iter)
1529 for_each_tracing_cpu(cpu) {
1530 if (iter->buffer_iter[cpu]) {
1531 if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
1534 if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu))
1542 static enum print_line_t print_trace_line(struct trace_iterator *iter)
1544 enum print_line_t ret;
1546 if (iter->trace && iter->trace->print_line) {
1547 ret = iter->trace->print_line(iter);
1548 if (ret != TRACE_TYPE_UNHANDLED)
1552 if (iter->ent->type == TRACE_PRINT &&
1553 trace_flags & TRACE_ITER_PRINTK &&
1554 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
1555 return print_printk_msg_only(iter);
1557 if (trace_flags & TRACE_ITER_BIN)
1558 return print_bin_fmt(iter);
1560 if (trace_flags & TRACE_ITER_HEX)
1561 return print_hex_fmt(iter);
1563 if (trace_flags & TRACE_ITER_RAW)
1564 return print_raw_fmt(iter);
1566 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
1567 return print_lat_fmt(iter);
1569 return print_trace_fmt(iter);
1572 static int s_show(struct seq_file *m, void *v)
1574 struct trace_iterator *iter = v;
1576 if (iter->ent == NULL) {
1578 seq_printf(m, "# tracer: %s\n", iter->trace->name);
1581 if (iter->trace && iter->trace->print_header)
1582 iter->trace->print_header(m);
1583 else if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
1584 /* print nothing if the buffers are empty */
1585 if (trace_empty(iter))
1587 print_trace_header(m, iter);
1588 if (!(trace_flags & TRACE_ITER_VERBOSE))
1589 print_lat_help_header(m);
1591 if (!(trace_flags & TRACE_ITER_VERBOSE))
1592 print_func_help_header(m);
1595 print_trace_line(iter);
1596 trace_print_seq(m, &iter->seq);
1602 static struct seq_operations tracer_seq_ops = {
1609 static struct trace_iterator *
1610 __tracing_open(struct inode *inode, struct file *file, int *ret)
1612 struct trace_iterator *iter;
1616 if (tracing_disabled) {
1621 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1627 mutex_lock(&trace_types_lock);
1628 if (current_trace && current_trace->print_max)
1631 iter->tr = inode->i_private;
1632 iter->trace = current_trace;
1635 /* Notify the tracer early; before we stop tracing. */
1636 if (iter->trace && iter->trace->open)
1637 iter->trace->open(iter);
1639 /* Annotate start of buffers if we had overruns */
1640 if (ring_buffer_overruns(iter->tr->buffer))
1641 iter->iter_flags |= TRACE_FILE_ANNOTATE;
1644 for_each_tracing_cpu(cpu) {
1646 iter->buffer_iter[cpu] =
1647 ring_buffer_read_start(iter->tr->buffer, cpu);
1649 if (!iter->buffer_iter[cpu])
1653 /* TODO stop tracer */
1654 *ret = seq_open(file, &tracer_seq_ops);
1658 m = file->private_data;
1661 /* stop the trace while dumping */
1664 mutex_unlock(&trace_types_lock);
1670 for_each_tracing_cpu(cpu) {
1671 if (iter->buffer_iter[cpu])
1672 ring_buffer_read_finish(iter->buffer_iter[cpu]);
1674 mutex_unlock(&trace_types_lock);
1677 return ERR_PTR(-ENOMEM);
1680 int tracing_open_generic(struct inode *inode, struct file *filp)
1682 if (tracing_disabled)
1685 filp->private_data = inode->i_private;
1689 int tracing_release(struct inode *inode, struct file *file)
1691 struct seq_file *m = (struct seq_file *)file->private_data;
1692 struct trace_iterator *iter = m->private;
1695 mutex_lock(&trace_types_lock);
1696 for_each_tracing_cpu(cpu) {
1697 if (iter->buffer_iter[cpu])
1698 ring_buffer_read_finish(iter->buffer_iter[cpu]);
1701 if (iter->trace && iter->trace->close)
1702 iter->trace->close(iter);
1704 /* reenable tracing if it was previously enabled */
1706 mutex_unlock(&trace_types_lock);
1708 seq_release(inode, file);
1713 static int tracing_open(struct inode *inode, struct file *file)
1717 __tracing_open(inode, file, &ret);
1722 static int tracing_lt_open(struct inode *inode, struct file *file)
1724 struct trace_iterator *iter;
1727 iter = __tracing_open(inode, file, &ret);
1730 iter->iter_flags |= TRACE_FILE_LAT_FMT;
1737 t_next(struct seq_file *m, void *v, loff_t *pos)
1739 struct tracer *t = m->private;
1751 static void *t_start(struct seq_file *m, loff_t *pos)
1753 struct tracer *t = m->private;
1756 mutex_lock(&trace_types_lock);
1757 for (; t && l < *pos; t = t_next(m, t, &l))
1763 static void t_stop(struct seq_file *m, void *p)
1765 mutex_unlock(&trace_types_lock);
1768 static int t_show(struct seq_file *m, void *v)
1770 struct tracer *t = v;
1775 seq_printf(m, "%s", t->name);
1784 static struct seq_operations show_traces_seq_ops = {
1791 static int show_traces_open(struct inode *inode, struct file *file)
1795 if (tracing_disabled)
1798 ret = seq_open(file, &show_traces_seq_ops);
1800 struct seq_file *m = file->private_data;
1801 m->private = trace_types;
1807 static struct file_operations tracing_fops = {
1808 .open = tracing_open,
1810 .llseek = seq_lseek,
1811 .release = tracing_release,
1814 static struct file_operations tracing_lt_fops = {
1815 .open = tracing_lt_open,
1817 .llseek = seq_lseek,
1818 .release = tracing_release,
1821 static struct file_operations show_traces_fops = {
1822 .open = show_traces_open,
1824 .release = seq_release,
1828 * Only trace on a CPU if the bitmask is set:
1830 static cpumask_var_t tracing_cpumask;
1833 * The tracer itself will not take this lock, but still we want
1834 * to provide a consistent cpumask to user-space:
1836 static DEFINE_MUTEX(tracing_cpumask_update_lock);
1839 * Temporary storage for the character representation of the
1840 * CPU bitmask (and one more byte for the newline):
1842 static char mask_str[NR_CPUS + 1];
1845 tracing_cpumask_read(struct file *filp, char __user *ubuf,
1846 size_t count, loff_t *ppos)
1850 mutex_lock(&tracing_cpumask_update_lock);
1852 len = cpumask_scnprintf(mask_str, count, tracing_cpumask);
1853 if (count - len < 2) {
1857 len += sprintf(mask_str + len, "\n");
1858 count = simple_read_from_buffer(ubuf, count, ppos, mask_str, NR_CPUS+1);
1861 mutex_unlock(&tracing_cpumask_update_lock);
1867 tracing_cpumask_write(struct file *filp, const char __user *ubuf,
1868 size_t count, loff_t *ppos)
1871 cpumask_var_t tracing_cpumask_new;
1873 if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
1876 mutex_lock(&tracing_cpumask_update_lock);
1877 err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
1881 local_irq_disable();
1882 __raw_spin_lock(&ftrace_max_lock);
1883 for_each_tracing_cpu(cpu) {
1885 * Increase/decrease the disabled counter if we are
1886 * about to flip a bit in the cpumask:
1888 if (cpumask_test_cpu(cpu, tracing_cpumask) &&
1889 !cpumask_test_cpu(cpu, tracing_cpumask_new)) {
1890 atomic_inc(&global_trace.data[cpu]->disabled);
1892 if (!cpumask_test_cpu(cpu, tracing_cpumask) &&
1893 cpumask_test_cpu(cpu, tracing_cpumask_new)) {
1894 atomic_dec(&global_trace.data[cpu]->disabled);
1897 __raw_spin_unlock(&ftrace_max_lock);
1900 cpumask_copy(tracing_cpumask, tracing_cpumask_new);
1902 mutex_unlock(&tracing_cpumask_update_lock);
1903 free_cpumask_var(tracing_cpumask_new);
1908 mutex_unlock(&tracing_cpumask_update_lock);
1909 free_cpumask_var(tracing_cpumask);
1914 static struct file_operations tracing_cpumask_fops = {
1915 .open = tracing_open_generic,
1916 .read = tracing_cpumask_read,
1917 .write = tracing_cpumask_write,
1921 tracing_trace_options_read(struct file *filp, char __user *ubuf,
1922 size_t cnt, loff_t *ppos)
1928 u32 tracer_flags = current_trace->flags->val;
1929 struct tracer_opt *trace_opts = current_trace->flags->opts;
1932 /* calulate max size */
1933 for (i = 0; trace_options[i]; i++) {
1934 len += strlen(trace_options[i]);
1935 len += 3; /* "no" and space */
1939 * Increase the size with names of options specific
1940 * of the current tracer.
1942 for (i = 0; trace_opts[i].name; i++) {
1943 len += strlen(trace_opts[i].name);
1944 len += 3; /* "no" and space */
1947 /* +2 for \n and \0 */
1948 buf = kmalloc(len + 2, GFP_KERNEL);
1952 for (i = 0; trace_options[i]; i++) {
1953 if (trace_flags & (1 << i))
1954 r += sprintf(buf + r, "%s ", trace_options[i]);
1956 r += sprintf(buf + r, "no%s ", trace_options[i]);
1959 for (i = 0; trace_opts[i].name; i++) {
1960 if (tracer_flags & trace_opts[i].bit)
1961 r += sprintf(buf + r, "%s ",
1962 trace_opts[i].name);
1964 r += sprintf(buf + r, "no%s ",
1965 trace_opts[i].name);
1968 r += sprintf(buf + r, "\n");
1969 WARN_ON(r >= len + 2);
1971 r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
1978 /* Try to assign a tracer specific option */
1979 static int set_tracer_option(struct tracer *trace, char *cmp, int neg)
1981 struct tracer_flags *trace_flags = trace->flags;
1982 struct tracer_opt *opts = NULL;
1986 for (i = 0; trace_flags->opts[i].name; i++) {
1987 opts = &trace_flags->opts[i];
1988 len = strlen(opts->name);
1990 if (strncmp(cmp, opts->name, len) == 0) {
1991 ret = trace->set_flag(trace_flags->val,
1997 if (!trace_flags->opts[i].name)
2000 /* Refused to handle */
2005 trace_flags->val &= ~opts->bit;
2007 trace_flags->val |= opts->bit;
2013 tracing_trace_options_write(struct file *filp, const char __user *ubuf,
2014 size_t cnt, loff_t *ppos)
2022 if (cnt >= sizeof(buf))
2025 if (copy_from_user(&buf, ubuf, cnt))
2030 if (strncmp(buf, "no", 2) == 0) {
2035 for (i = 0; trace_options[i]; i++) {
2036 int len = strlen(trace_options[i]);
2038 if (strncmp(cmp, trace_options[i], len) == 0) {
2040 trace_flags &= ~(1 << i);
2042 trace_flags |= (1 << i);
2047 /* If no option could be set, test the specific tracer options */
2048 if (!trace_options[i]) {
2049 ret = set_tracer_option(current_trace, cmp, neg);
2059 static struct file_operations tracing_iter_fops = {
2060 .open = tracing_open_generic,
2061 .read = tracing_trace_options_read,
2062 .write = tracing_trace_options_write,
2065 static const char readme_msg[] =
2066 "tracing mini-HOWTO:\n\n"
2068 "# mount -t debugfs nodev /debug\n\n"
2069 "# cat /debug/tracing/available_tracers\n"
2070 "wakeup preemptirqsoff preemptoff irqsoff ftrace sched_switch none\n\n"
2071 "# cat /debug/tracing/current_tracer\n"
2073 "# echo sched_switch > /debug/tracing/current_tracer\n"
2074 "# cat /debug/tracing/current_tracer\n"
2076 "# cat /debug/tracing/trace_options\n"
2077 "noprint-parent nosym-offset nosym-addr noverbose\n"
2078 "# echo print-parent > /debug/tracing/trace_options\n"
2079 "# echo 1 > /debug/tracing/tracing_enabled\n"
2080 "# cat /debug/tracing/trace > /tmp/trace.txt\n"
2081 "echo 0 > /debug/tracing/tracing_enabled\n"
2085 tracing_readme_read(struct file *filp, char __user *ubuf,
2086 size_t cnt, loff_t *ppos)
2088 return simple_read_from_buffer(ubuf, cnt, ppos,
2089 readme_msg, strlen(readme_msg));
2092 static struct file_operations tracing_readme_fops = {
2093 .open = tracing_open_generic,
2094 .read = tracing_readme_read,
2098 tracing_ctrl_read(struct file *filp, char __user *ubuf,
2099 size_t cnt, loff_t *ppos)
2104 r = sprintf(buf, "%u\n", tracer_enabled);
2105 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2109 tracing_ctrl_write(struct file *filp, const char __user *ubuf,
2110 size_t cnt, loff_t *ppos)
2112 struct trace_array *tr = filp->private_data;
2117 if (cnt >= sizeof(buf))
2120 if (copy_from_user(&buf, ubuf, cnt))
2125 ret = strict_strtoul(buf, 10, &val);
2131 mutex_lock(&trace_types_lock);
2132 if (tracer_enabled ^ val) {
2135 if (current_trace->start)
2136 current_trace->start(tr);
2141 if (current_trace->stop)
2142 current_trace->stop(tr);
2145 mutex_unlock(&trace_types_lock);
2153 tracing_set_trace_read(struct file *filp, char __user *ubuf,
2154 size_t cnt, loff_t *ppos)
2156 char buf[max_tracer_type_len+2];
2159 mutex_lock(&trace_types_lock);
2161 r = sprintf(buf, "%s\n", current_trace->name);
2163 r = sprintf(buf, "\n");
2164 mutex_unlock(&trace_types_lock);
2166 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2169 static int tracing_set_tracer(char *buf)
2171 struct trace_array *tr = &global_trace;
2175 mutex_lock(&trace_types_lock);
2176 for (t = trace_types; t; t = t->next) {
2177 if (strcmp(t->name, buf) == 0)
2184 if (t == current_trace)
2187 trace_branch_disable();
2188 if (current_trace && current_trace->reset)
2189 current_trace->reset(tr);
2198 trace_branch_enable(tr);
2200 mutex_unlock(&trace_types_lock);
2206 tracing_set_trace_write(struct file *filp, const char __user *ubuf,
2207 size_t cnt, loff_t *ppos)
2209 char buf[max_tracer_type_len+1];
2216 if (cnt > max_tracer_type_len)
2217 cnt = max_tracer_type_len;
2219 if (copy_from_user(&buf, ubuf, cnt))
2224 /* strip ending whitespace. */
2225 for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
2228 err = tracing_set_tracer(buf);
2238 tracing_max_lat_read(struct file *filp, char __user *ubuf,
2239 size_t cnt, loff_t *ppos)
2241 unsigned long *ptr = filp->private_data;
2245 r = snprintf(buf, sizeof(buf), "%ld\n",
2246 *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
2247 if (r > sizeof(buf))
2249 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2253 tracing_max_lat_write(struct file *filp, const char __user *ubuf,
2254 size_t cnt, loff_t *ppos)
2256 long *ptr = filp->private_data;
2261 if (cnt >= sizeof(buf))
2264 if (copy_from_user(&buf, ubuf, cnt))
2269 ret = strict_strtoul(buf, 10, &val);
2278 static atomic_t tracing_reader;
2280 static int tracing_open_pipe(struct inode *inode, struct file *filp)
2282 struct trace_iterator *iter;
2284 if (tracing_disabled)
2287 /* We only allow for reader of the pipe */
2288 if (atomic_inc_return(&tracing_reader) != 1) {
2289 atomic_dec(&tracing_reader);
2293 /* create a buffer to store the information to pass to userspace */
2294 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2298 if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
2303 mutex_lock(&trace_types_lock);
2305 /* trace pipe does not show start of buffer */
2306 cpumask_setall(iter->started);
2308 iter->tr = &global_trace;
2309 iter->trace = current_trace;
2310 filp->private_data = iter;
2312 if (iter->trace->pipe_open)
2313 iter->trace->pipe_open(iter);
2314 mutex_unlock(&trace_types_lock);
2319 static int tracing_release_pipe(struct inode *inode, struct file *file)
2321 struct trace_iterator *iter = file->private_data;
2323 free_cpumask_var(iter->started);
2325 atomic_dec(&tracing_reader);
2331 tracing_poll_pipe(struct file *filp, poll_table *poll_table)
2333 struct trace_iterator *iter = filp->private_data;
2335 if (trace_flags & TRACE_ITER_BLOCK) {
2337 * Always select as readable when in blocking mode
2339 return POLLIN | POLLRDNORM;
2341 if (!trace_empty(iter))
2342 return POLLIN | POLLRDNORM;
2343 poll_wait(filp, &trace_wait, poll_table);
2344 if (!trace_empty(iter))
2345 return POLLIN | POLLRDNORM;
2355 tracing_read_pipe(struct file *filp, char __user *ubuf,
2356 size_t cnt, loff_t *ppos)
2358 struct trace_iterator *iter = filp->private_data;
2361 /* return any leftover data */
2362 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
2366 trace_seq_reset(&iter->seq);
2368 mutex_lock(&trace_types_lock);
2369 if (iter->trace->read) {
2370 sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
2377 while (trace_empty(iter)) {
2379 if ((filp->f_flags & O_NONBLOCK)) {
2385 * This is a make-shift waitqueue. The reason we don't use
2386 * an actual wait queue is because:
2387 * 1) we only ever have one waiter
2388 * 2) the tracing, traces all functions, we don't want
2389 * the overhead of calling wake_up and friends
2390 * (and tracing them too)
2391 * Anyway, this is really very primitive wakeup.
2393 set_current_state(TASK_INTERRUPTIBLE);
2394 iter->tr->waiter = current;
2396 mutex_unlock(&trace_types_lock);
2398 /* sleep for 100 msecs, and try again. */
2399 schedule_timeout(HZ/10);
2401 mutex_lock(&trace_types_lock);
2403 iter->tr->waiter = NULL;
2405 if (signal_pending(current)) {
2410 if (iter->trace != current_trace)
2414 * We block until we read something and tracing is disabled.
2415 * We still block if tracing is disabled, but we have never
2416 * read anything. This allows a user to cat this file, and
2417 * then enable tracing. But after we have read something,
2418 * we give an EOF when tracing is again disabled.
2420 * iter->pos will be 0 if we haven't read anything.
2422 if (!tracer_enabled && iter->pos)
2428 /* stop when tracing is finished */
2429 if (trace_empty(iter))
2432 if (cnt >= PAGE_SIZE)
2433 cnt = PAGE_SIZE - 1;
2435 /* reset all but tr, trace, and overruns */
2436 memset(&iter->seq, 0,
2437 sizeof(struct trace_iterator) -
2438 offsetof(struct trace_iterator, seq));
2441 while (find_next_entry_inc(iter) != NULL) {
2442 enum print_line_t ret;
2443 int len = iter->seq.len;
2445 ret = print_trace_line(iter);
2446 if (ret == TRACE_TYPE_PARTIAL_LINE) {
2447 /* don't print partial lines */
2448 iter->seq.len = len;
2452 trace_consume(iter);
2454 if (iter->seq.len >= cnt)
2458 /* Now copy what we have to the user */
2459 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
2460 if (iter->seq.readpos >= iter->seq.len)
2461 trace_seq_reset(&iter->seq);
2464 * If there was nothing to send to user, inspite of consuming trace
2465 * entries, go back to wait for more entries.
2471 mutex_unlock(&trace_types_lock);
2477 tracing_entries_read(struct file *filp, char __user *ubuf,
2478 size_t cnt, loff_t *ppos)
2480 struct trace_array *tr = filp->private_data;
2484 r = sprintf(buf, "%lu\n", tr->entries >> 10);
2485 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2489 tracing_entries_write(struct file *filp, const char __user *ubuf,
2490 size_t cnt, loff_t *ppos)
2496 if (cnt >= sizeof(buf))
2499 if (copy_from_user(&buf, ubuf, cnt))
2504 ret = strict_strtoul(buf, 10, &val);
2508 /* must have at least 1 entry */
2512 mutex_lock(&trace_types_lock);
2516 /* disable all cpu buffers */
2517 for_each_tracing_cpu(cpu) {
2518 if (global_trace.data[cpu])
2519 atomic_inc(&global_trace.data[cpu]->disabled);
2520 if (max_tr.data[cpu])
2521 atomic_inc(&max_tr.data[cpu]->disabled);
2524 /* value is in KB */
2527 if (val != global_trace.entries) {
2528 ret = ring_buffer_resize(global_trace.buffer, val);
2534 ret = ring_buffer_resize(max_tr.buffer, val);
2538 r = ring_buffer_resize(global_trace.buffer,
2539 global_trace.entries);
2541 /* AARGH! We are left with different
2542 * size max buffer!!!! */
2544 tracing_disabled = 1;
2549 global_trace.entries = val;
2554 /* If check pages failed, return ENOMEM */
2555 if (tracing_disabled)
2558 for_each_tracing_cpu(cpu) {
2559 if (global_trace.data[cpu])
2560 atomic_dec(&global_trace.data[cpu]->disabled);
2561 if (max_tr.data[cpu])
2562 atomic_dec(&max_tr.data[cpu]->disabled);
2566 max_tr.entries = global_trace.entries;
2567 mutex_unlock(&trace_types_lock);
2572 static int mark_printk(const char *fmt, ...)
2576 va_start(args, fmt);
2577 ret = trace_vprintk(0, -1, fmt, args);
2583 tracing_mark_write(struct file *filp, const char __user *ubuf,
2584 size_t cnt, loff_t *fpos)
2589 if (tracing_disabled)
2592 if (cnt > TRACE_BUF_SIZE)
2593 cnt = TRACE_BUF_SIZE;
2595 buf = kmalloc(cnt + 1, GFP_KERNEL);
2599 if (copy_from_user(buf, ubuf, cnt)) {
2604 /* Cut from the first nil or newline. */
2606 end = strchr(buf, '\n');
2610 cnt = mark_printk("%s\n", buf);
2617 static struct file_operations tracing_max_lat_fops = {
2618 .open = tracing_open_generic,
2619 .read = tracing_max_lat_read,
2620 .write = tracing_max_lat_write,
2623 static struct file_operations tracing_ctrl_fops = {
2624 .open = tracing_open_generic,
2625 .read = tracing_ctrl_read,
2626 .write = tracing_ctrl_write,
2629 static struct file_operations set_tracer_fops = {
2630 .open = tracing_open_generic,
2631 .read = tracing_set_trace_read,
2632 .write = tracing_set_trace_write,
2635 static struct file_operations tracing_pipe_fops = {
2636 .open = tracing_open_pipe,
2637 .poll = tracing_poll_pipe,
2638 .read = tracing_read_pipe,
2639 .release = tracing_release_pipe,
2642 static struct file_operations tracing_entries_fops = {
2643 .open = tracing_open_generic,
2644 .read = tracing_entries_read,
2645 .write = tracing_entries_write,
2648 static struct file_operations tracing_mark_fops = {
2649 .open = tracing_open_generic,
2650 .write = tracing_mark_write,
2653 #ifdef CONFIG_DYNAMIC_FTRACE
2655 int __weak ftrace_arch_read_dyn_info(char *buf, int size)
2661 tracing_read_dyn_info(struct file *filp, char __user *ubuf,
2662 size_t cnt, loff_t *ppos)
2664 static char ftrace_dyn_info_buffer[1024];
2665 static DEFINE_MUTEX(dyn_info_mutex);
2666 unsigned long *p = filp->private_data;
2667 char *buf = ftrace_dyn_info_buffer;
2668 int size = ARRAY_SIZE(ftrace_dyn_info_buffer);
2671 mutex_lock(&dyn_info_mutex);
2672 r = sprintf(buf, "%ld ", *p);
2674 r += ftrace_arch_read_dyn_info(buf+r, (size-1)-r);
2677 r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2679 mutex_unlock(&dyn_info_mutex);
2684 static struct file_operations tracing_dyn_info_fops = {
2685 .open = tracing_open_generic,
2686 .read = tracing_read_dyn_info,
2690 static struct dentry *d_tracer;
2692 struct dentry *tracing_init_dentry(void)
2699 d_tracer = debugfs_create_dir("tracing", NULL);
2701 if (!d_tracer && !once) {
2703 pr_warning("Could not create debugfs directory 'tracing'\n");
2710 #ifdef CONFIG_FTRACE_SELFTEST
2711 /* Let selftest have access to static functions in this file */
2712 #include "trace_selftest.c"
2715 static __init int tracer_init_debugfs(void)
2717 struct dentry *d_tracer;
2718 struct dentry *entry;
2720 d_tracer = tracing_init_dentry();
2722 entry = debugfs_create_file("tracing_enabled", 0644, d_tracer,
2723 &global_trace, &tracing_ctrl_fops);
2725 pr_warning("Could not create debugfs 'tracing_enabled' entry\n");
2727 entry = debugfs_create_file("trace_options", 0644, d_tracer,
2728 NULL, &tracing_iter_fops);
2730 pr_warning("Could not create debugfs 'trace_options' entry\n");
2732 entry = debugfs_create_file("tracing_cpumask", 0644, d_tracer,
2733 NULL, &tracing_cpumask_fops);
2735 pr_warning("Could not create debugfs 'tracing_cpumask' entry\n");
2737 entry = debugfs_create_file("latency_trace", 0444, d_tracer,
2738 &global_trace, &tracing_lt_fops);
2740 pr_warning("Could not create debugfs 'latency_trace' entry\n");
2742 entry = debugfs_create_file("trace", 0444, d_tracer,
2743 &global_trace, &tracing_fops);
2745 pr_warning("Could not create debugfs 'trace' entry\n");
2747 entry = debugfs_create_file("available_tracers", 0444, d_tracer,
2748 &global_trace, &show_traces_fops);
2750 pr_warning("Could not create debugfs 'available_tracers' entry\n");
2752 entry = debugfs_create_file("current_tracer", 0444, d_tracer,
2753 &global_trace, &set_tracer_fops);
2755 pr_warning("Could not create debugfs 'current_tracer' entry\n");
2757 entry = debugfs_create_file("tracing_max_latency", 0644, d_tracer,
2758 &tracing_max_latency,
2759 &tracing_max_lat_fops);
2761 pr_warning("Could not create debugfs "
2762 "'tracing_max_latency' entry\n");
2764 entry = debugfs_create_file("tracing_thresh", 0644, d_tracer,
2765 &tracing_thresh, &tracing_max_lat_fops);
2767 pr_warning("Could not create debugfs "
2768 "'tracing_thresh' entry\n");
2769 entry = debugfs_create_file("README", 0644, d_tracer,
2770 NULL, &tracing_readme_fops);
2772 pr_warning("Could not create debugfs 'README' entry\n");
2774 entry = debugfs_create_file("trace_pipe", 0644, d_tracer,
2775 NULL, &tracing_pipe_fops);
2777 pr_warning("Could not create debugfs "
2778 "'trace_pipe' entry\n");
2780 entry = debugfs_create_file("buffer_size_kb", 0644, d_tracer,
2781 &global_trace, &tracing_entries_fops);
2783 pr_warning("Could not create debugfs "
2784 "'buffer_size_kb' entry\n");
2786 entry = debugfs_create_file("trace_marker", 0220, d_tracer,
2787 NULL, &tracing_mark_fops);
2789 pr_warning("Could not create debugfs "
2790 "'trace_marker' entry\n");
2792 #ifdef CONFIG_DYNAMIC_FTRACE
2793 entry = debugfs_create_file("dyn_ftrace_total_info", 0444, d_tracer,
2794 &ftrace_update_tot_cnt,
2795 &tracing_dyn_info_fops);
2797 pr_warning("Could not create debugfs "
2798 "'dyn_ftrace_total_info' entry\n");
2800 #ifdef CONFIG_SYSPROF_TRACER
2801 init_tracer_sysprof_debugfs(d_tracer);
2806 int trace_vprintk(unsigned long ip, int depth, const char *fmt, va_list args)
2808 static DEFINE_SPINLOCK(trace_buf_lock);
2809 static char trace_buf[TRACE_BUF_SIZE];
2811 struct ring_buffer_event *event;
2812 struct trace_array *tr = &global_trace;
2813 struct trace_array_cpu *data;
2814 int cpu, len = 0, size, pc;
2815 struct print_entry *entry;
2816 unsigned long irq_flags;
2818 if (tracing_disabled || tracing_selftest_running)
2821 pc = preempt_count();
2822 preempt_disable_notrace();
2823 cpu = raw_smp_processor_id();
2824 data = tr->data[cpu];
2826 if (unlikely(atomic_read(&data->disabled)))
2829 pause_graph_tracing();
2830 spin_lock_irqsave(&trace_buf_lock, irq_flags);
2831 len = vsnprintf(trace_buf, TRACE_BUF_SIZE, fmt, args);
2833 len = min(len, TRACE_BUF_SIZE-1);
2836 size = sizeof(*entry) + len + 1;
2837 event = ring_buffer_lock_reserve(tr->buffer, size, &irq_flags);
2840 entry = ring_buffer_event_data(event);
2841 tracing_generic_entry_update(&entry->ent, irq_flags, pc);
2842 entry->ent.type = TRACE_PRINT;
2844 entry->depth = depth;
2846 memcpy(&entry->buf, trace_buf, len);
2847 entry->buf[len] = 0;
2848 ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
2851 spin_unlock_irqrestore(&trace_buf_lock, irq_flags);
2852 unpause_graph_tracing();
2854 preempt_enable_notrace();
2858 EXPORT_SYMBOL_GPL(trace_vprintk);
2860 int __ftrace_printk(unsigned long ip, const char *fmt, ...)
2865 if (!(trace_flags & TRACE_ITER_PRINTK))
2869 ret = trace_vprintk(ip, task_curr_ret_stack(current), fmt, ap);
2873 EXPORT_SYMBOL_GPL(__ftrace_printk);
2875 int __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap)
2877 if (!(trace_flags & TRACE_ITER_PRINTK))
2880 return trace_vprintk(ip, task_curr_ret_stack(current), fmt, ap);
2882 EXPORT_SYMBOL_GPL(__ftrace_vprintk);
2884 static int trace_panic_handler(struct notifier_block *this,
2885 unsigned long event, void *unused)
2887 if (ftrace_dump_on_oops)
2892 static struct notifier_block trace_panic_notifier = {
2893 .notifier_call = trace_panic_handler,
2895 .priority = 150 /* priority: INT_MAX >= x >= 0 */
2898 static int trace_die_handler(struct notifier_block *self,
2904 if (ftrace_dump_on_oops)
2913 static struct notifier_block trace_die_notifier = {
2914 .notifier_call = trace_die_handler,
2919 * printk is set to max of 1024, we really don't need it that big.
2920 * Nothing should be printing 1000 characters anyway.
2922 #define TRACE_MAX_PRINT 1000
2925 * Define here KERN_TRACE so that we have one place to modify
2926 * it if we decide to change what log level the ftrace dump
2929 #define KERN_TRACE KERN_EMERG
2932 trace_printk_seq(struct trace_seq *s)
2934 /* Probably should print a warning here. */
2938 /* should be zero ended, but we are paranoid. */
2939 s->buffer[s->len] = 0;
2941 printk(KERN_TRACE "%s", s->buffer);
2946 void ftrace_dump(void)
2948 static DEFINE_SPINLOCK(ftrace_dump_lock);
2949 /* use static because iter can be a bit big for the stack */
2950 static struct trace_iterator iter;
2951 static int dump_ran;
2952 unsigned long flags;
2956 spin_lock_irqsave(&ftrace_dump_lock, flags);
2962 /* No turning back! */
2966 for_each_tracing_cpu(cpu) {
2967 atomic_inc(&global_trace.data[cpu]->disabled);
2970 /* don't look at user memory in panic mode */
2971 trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
2973 printk(KERN_TRACE "Dumping ftrace buffer:\n");
2975 iter.tr = &global_trace;
2976 iter.trace = current_trace;
2979 * We need to stop all tracing on all CPUS to read the
2980 * the next buffer. This is a bit expensive, but is
2981 * not done often. We fill all what we can read,
2982 * and then release the locks again.
2985 while (!trace_empty(&iter)) {
2988 printk(KERN_TRACE "---------------------------------\n");
2992 /* reset all but tr, trace, and overruns */
2993 memset(&iter.seq, 0,
2994 sizeof(struct trace_iterator) -
2995 offsetof(struct trace_iterator, seq));
2996 iter.iter_flags |= TRACE_FILE_LAT_FMT;
2999 if (find_next_entry_inc(&iter) != NULL) {
3000 print_trace_line(&iter);
3001 trace_consume(&iter);
3004 trace_printk_seq(&iter.seq);
3008 printk(KERN_TRACE " (ftrace buffer empty)\n");
3010 printk(KERN_TRACE "---------------------------------\n");
3013 spin_unlock_irqrestore(&ftrace_dump_lock, flags);
3016 __init static int tracer_alloc_buffers(void)
3018 struct trace_array_cpu *data;
3022 if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
3025 if (!alloc_cpumask_var(&tracing_cpumask, GFP_KERNEL))
3026 goto out_free_buffer_mask;
3028 cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
3029 cpumask_copy(tracing_cpumask, cpu_all_mask);
3031 /* TODO: make the number of buffers hot pluggable with CPUS */
3032 global_trace.buffer = ring_buffer_alloc(trace_buf_size,
3033 TRACE_BUFFER_FLAGS);
3034 if (!global_trace.buffer) {
3035 printk(KERN_ERR "tracer: failed to allocate ring buffer!\n");
3037 goto out_free_cpumask;
3039 global_trace.entries = ring_buffer_size(global_trace.buffer);
3042 #ifdef CONFIG_TRACER_MAX_TRACE
3043 max_tr.buffer = ring_buffer_alloc(trace_buf_size,
3044 TRACE_BUFFER_FLAGS);
3045 if (!max_tr.buffer) {
3046 printk(KERN_ERR "tracer: failed to allocate max ring buffer!\n");
3048 ring_buffer_free(global_trace.buffer);
3049 goto out_free_cpumask;
3051 max_tr.entries = ring_buffer_size(max_tr.buffer);
3052 WARN_ON(max_tr.entries != global_trace.entries);
3055 /* Allocate the first page for all buffers */
3056 for_each_tracing_cpu(i) {
3057 data = global_trace.data[i] = &per_cpu(global_trace_cpu, i);
3058 max_tr.data[i] = &per_cpu(max_data, i);
3061 trace_init_cmdlines();
3063 register_tracer(&nop_trace);
3064 #ifdef CONFIG_BOOT_TRACER
3065 register_tracer(&boot_tracer);
3066 current_trace = &boot_tracer;
3067 current_trace->init(&global_trace);
3069 current_trace = &nop_trace;
3071 /* All seems OK, enable tracing */
3072 tracing_disabled = 0;
3074 atomic_notifier_chain_register(&panic_notifier_list,
3075 &trace_panic_notifier);
3077 register_die_notifier(&trace_die_notifier);
3081 free_cpumask_var(tracing_cpumask);
3082 out_free_buffer_mask:
3083 free_cpumask_var(tracing_buffer_mask);
3087 early_initcall(tracer_alloc_buffers);
3088 fs_initcall(tracer_init_debugfs);