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>
41 #define TRACE_BUFFER_FLAGS (RB_FL_OVERWRITE)
43 unsigned long __read_mostly tracing_max_latency = (cycle_t)ULONG_MAX;
44 unsigned long __read_mostly tracing_thresh;
48 * Kill all tracing for good (never come back).
49 * It is initialized to 1 but will turn to zero if the initialization
50 * of the tracer is successful. But that is the only place that sets
53 int tracing_disabled = 1;
55 static DEFINE_PER_CPU(local_t, ftrace_cpu_disabled);
57 static inline void ftrace_disable_cpu(void)
60 local_inc(&__get_cpu_var(ftrace_cpu_disabled));
63 static inline void ftrace_enable_cpu(void)
65 local_dec(&__get_cpu_var(ftrace_cpu_disabled));
69 static cpumask_t __read_mostly tracing_buffer_mask;
71 #define for_each_tracing_cpu(cpu) \
72 for_each_cpu_mask(cpu, tracing_buffer_mask)
75 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
77 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
78 * is set, then ftrace_dump is called. This will output the contents
79 * of the ftrace buffers to the console. This is very useful for
80 * capturing traces that lead to crashes and outputing it to a
83 * It is default off, but you can enable it with either specifying
84 * "ftrace_dump_on_oops" in the kernel command line, or setting
85 * /proc/sys/kernel/ftrace_dump_on_oops to true.
87 int ftrace_dump_on_oops;
89 static int tracing_set_tracer(char *buf);
91 static int __init set_ftrace(char *str)
93 tracing_set_tracer(str);
96 __setup("ftrace", set_ftrace);
98 static int __init set_ftrace_dump_on_oops(char *str)
100 ftrace_dump_on_oops = 1;
103 __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
106 ns2usecs(cycle_t nsec)
113 cycle_t ftrace_now(int cpu)
115 u64 ts = ring_buffer_time_stamp(cpu);
116 ring_buffer_normalize_time_stamp(cpu, &ts);
121 * The global_trace is the descriptor that holds the tracing
122 * buffers for the live tracing. For each CPU, it contains
123 * a link list of pages that will store trace entries. The
124 * page descriptor of the pages in the memory is used to hold
125 * the link list by linking the lru item in the page descriptor
126 * to each of the pages in the buffer per CPU.
128 * For each active CPU there is a data field that holds the
129 * pages for the buffer for that CPU. Each CPU has the same number
130 * of pages allocated for its buffer.
132 static struct trace_array global_trace;
134 static DEFINE_PER_CPU(struct trace_array_cpu, global_trace_cpu);
137 * The max_tr is used to snapshot the global_trace when a maximum
138 * latency is reached. Some tracers will use this to store a maximum
139 * trace while it continues examining live traces.
141 * The buffers for the max_tr are set up the same as the global_trace.
142 * When a snapshot is taken, the link list of the max_tr is swapped
143 * with the link list of the global_trace and the buffers are reset for
144 * the global_trace so the tracing can continue.
146 static struct trace_array max_tr;
148 static DEFINE_PER_CPU(struct trace_array_cpu, max_data);
150 /* tracer_enabled is used to toggle activation of a tracer */
151 static int tracer_enabled = 1;
154 * tracing_is_enabled - return tracer_enabled status
156 * This function is used by other tracers to know the status
157 * of the tracer_enabled flag. Tracers may use this function
158 * to know if it should enable their features when starting
159 * up. See irqsoff tracer for an example (start_irqsoff_tracer).
161 int tracing_is_enabled(void)
163 return tracer_enabled;
166 /* function tracing enabled */
167 int ftrace_function_enabled;
170 * trace_buf_size is the size in bytes that is allocated
171 * for a buffer. Note, the number of bytes is always rounded
174 * This number is purposely set to a low number of 16384.
175 * If the dump on oops happens, it will be much appreciated
176 * to not have to wait for all that output. Anyway this can be
177 * boot time and run time configurable.
179 #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
181 static unsigned long trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
183 /* trace_types holds a link list of available tracers. */
184 static struct tracer *trace_types __read_mostly;
186 /* current_trace points to the tracer that is currently active */
187 static struct tracer *current_trace __read_mostly;
190 * max_tracer_type_len is used to simplify the allocating of
191 * buffers to read userspace tracer names. We keep track of
192 * the longest tracer name registered.
194 static int max_tracer_type_len;
197 * trace_types_lock is used to protect the trace_types list.
198 * This lock is also used to keep user access serialized.
199 * Accesses from userspace will grab this lock while userspace
200 * activities happen inside the kernel.
202 static DEFINE_MUTEX(trace_types_lock);
204 /* trace_wait is a waitqueue for tasks blocked on trace_poll */
205 static DECLARE_WAIT_QUEUE_HEAD(trace_wait);
207 /* trace_flags holds iter_ctrl options */
208 unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK;
211 * trace_wake_up - wake up tasks waiting for trace input
213 * Simply wakes up any task that is blocked on the trace_wait
214 * queue. These is used with trace_poll for tasks polling the trace.
216 void trace_wake_up(void)
219 * The runqueue_is_locked() can fail, but this is the best we
222 if (!(trace_flags & TRACE_ITER_BLOCK) && !runqueue_is_locked())
223 wake_up(&trace_wait);
226 static int __init set_buf_size(char *str)
228 unsigned long buf_size;
233 ret = strict_strtoul(str, 0, &buf_size);
234 /* nr_entries can not be zero */
235 if (ret < 0 || buf_size == 0)
237 trace_buf_size = buf_size;
240 __setup("trace_buf_size=", set_buf_size);
242 unsigned long nsecs_to_usecs(unsigned long nsecs)
248 * TRACE_ITER_SYM_MASK masks the options in trace_flags that
249 * control the output of kernel symbols.
251 #define TRACE_ITER_SYM_MASK \
252 (TRACE_ITER_PRINT_PARENT|TRACE_ITER_SYM_OFFSET|TRACE_ITER_SYM_ADDR)
254 /* These must match the bit postions in trace_iterator_flags */
255 static const char *trace_options[] = {
272 * ftrace_max_lock is used to protect the swapping of buffers
273 * when taking a max snapshot. The buffers themselves are
274 * protected by per_cpu spinlocks. But the action of the swap
275 * needs its own lock.
277 * This is defined as a raw_spinlock_t in order to help
278 * with performance when lockdep debugging is enabled.
280 static raw_spinlock_t ftrace_max_lock =
281 (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
284 * Copy the new maximum trace into the separate maximum-trace
285 * structure. (this way the maximum trace is permanently saved,
286 * for later retrieval via /debugfs/tracing/latency_trace)
289 __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
291 struct trace_array_cpu *data = tr->data[cpu];
294 max_tr.time_start = data->preempt_timestamp;
296 data = max_tr.data[cpu];
297 data->saved_latency = tracing_max_latency;
299 memcpy(data->comm, tsk->comm, TASK_COMM_LEN);
300 data->pid = tsk->pid;
301 data->uid = tsk->uid;
302 data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
303 data->policy = tsk->policy;
304 data->rt_priority = tsk->rt_priority;
306 /* record this tasks comm */
307 tracing_record_cmdline(current);
311 * trace_seq_printf - sequence printing of trace information
312 * @s: trace sequence descriptor
313 * @fmt: printf format string
315 * The tracer may use either sequence operations or its own
316 * copy to user routines. To simplify formating of a trace
317 * trace_seq_printf is used to store strings into a special
318 * buffer (@s). Then the output may be either used by
319 * the sequencer or pulled into another buffer.
322 trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
324 int len = (PAGE_SIZE - 1) - s->len;
332 ret = vsnprintf(s->buffer + s->len, len, fmt, ap);
335 /* If we can't write it all, don't bother writing anything */
345 * trace_seq_puts - trace sequence printing of simple string
346 * @s: trace sequence descriptor
347 * @str: simple string to record
349 * The tracer may use either the sequence operations or its own
350 * copy to user routines. This function records a simple string
351 * into a special buffer (@s) for later retrieval by a sequencer
352 * or other mechanism.
355 trace_seq_puts(struct trace_seq *s, const char *str)
357 int len = strlen(str);
359 if (len > ((PAGE_SIZE - 1) - s->len))
362 memcpy(s->buffer + s->len, str, len);
369 trace_seq_putc(struct trace_seq *s, unsigned char c)
371 if (s->len >= (PAGE_SIZE - 1))
374 s->buffer[s->len++] = c;
380 trace_seq_putmem(struct trace_seq *s, void *mem, size_t len)
382 if (len > ((PAGE_SIZE - 1) - s->len))
385 memcpy(s->buffer + s->len, mem, len);
391 #define MAX_MEMHEX_BYTES 8
392 #define HEX_CHARS (MAX_MEMHEX_BYTES*2 + 1)
395 trace_seq_putmem_hex(struct trace_seq *s, void *mem, size_t len)
397 unsigned char hex[HEX_CHARS];
398 unsigned char *data = mem;
402 for (i = 0, j = 0; i < len; i++) {
404 for (i = len-1, j = 0; i >= 0; i--) {
406 hex[j++] = hex_asc_hi(data[i]);
407 hex[j++] = hex_asc_lo(data[i]);
411 return trace_seq_putmem(s, hex, j);
415 trace_seq_reset(struct trace_seq *s)
421 ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
426 if (s->len <= s->readpos)
429 len = s->len - s->readpos;
432 ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
441 trace_print_seq(struct seq_file *m, struct trace_seq *s)
443 int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len;
446 seq_puts(m, s->buffer);
452 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
454 * @tsk: the task with the latency
455 * @cpu: The cpu that initiated the trace.
457 * Flip the buffers between the @tr and the max_tr and record information
458 * about which task was the cause of this latency.
461 update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
463 struct ring_buffer *buf = tr->buffer;
465 WARN_ON_ONCE(!irqs_disabled());
466 __raw_spin_lock(&ftrace_max_lock);
468 tr->buffer = max_tr.buffer;
471 ftrace_disable_cpu();
472 ring_buffer_reset(tr->buffer);
475 __update_max_tr(tr, tsk, cpu);
476 __raw_spin_unlock(&ftrace_max_lock);
480 * update_max_tr_single - only copy one trace over, and reset the rest
482 * @tsk - task with the latency
483 * @cpu - the cpu of the buffer to copy.
485 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
488 update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
492 WARN_ON_ONCE(!irqs_disabled());
493 __raw_spin_lock(&ftrace_max_lock);
495 ftrace_disable_cpu();
497 ring_buffer_reset(max_tr.buffer);
498 ret = ring_buffer_swap_cpu(max_tr.buffer, tr->buffer, cpu);
504 __update_max_tr(tr, tsk, cpu);
505 __raw_spin_unlock(&ftrace_max_lock);
509 * register_tracer - register a tracer with the ftrace system.
510 * @type - the plugin for the tracer
512 * Register a new plugin tracer.
514 int register_tracer(struct tracer *type)
521 pr_info("Tracer must have a name\n");
525 mutex_lock(&trace_types_lock);
526 for (t = trace_types; t; t = t->next) {
527 if (strcmp(type->name, t->name) == 0) {
529 pr_info("Trace %s already registered\n",
536 #ifdef CONFIG_FTRACE_STARTUP_TEST
537 if (type->selftest) {
538 struct tracer *saved_tracer = current_trace;
539 struct trace_array *tr = &global_trace;
542 * Run a selftest on this tracer.
543 * Here we reset the trace buffer, and set the current
544 * tracer to be this tracer. The tracer can then run some
545 * internal tracing to verify that everything is in order.
546 * If we fail, we do not register this tracer.
548 for_each_tracing_cpu(i) {
549 tracing_reset(tr, i);
551 current_trace = type;
552 /* the test is responsible for initializing and enabling */
553 pr_info("Testing tracer %s: ", type->name);
554 ret = type->selftest(type, tr);
555 /* the test is responsible for resetting too */
556 current_trace = saved_tracer;
558 printk(KERN_CONT "FAILED!\n");
561 /* Only reset on passing, to avoid touching corrupted buffers */
562 for_each_tracing_cpu(i) {
563 tracing_reset(tr, i);
565 printk(KERN_CONT "PASSED\n");
569 type->next = trace_types;
571 len = strlen(type->name);
572 if (len > max_tracer_type_len)
573 max_tracer_type_len = len;
576 mutex_unlock(&trace_types_lock);
581 void unregister_tracer(struct tracer *type)
586 mutex_lock(&trace_types_lock);
587 for (t = &trace_types; *t; t = &(*t)->next) {
591 pr_info("Trace %s not registered\n", type->name);
596 if (strlen(type->name) != max_tracer_type_len)
599 max_tracer_type_len = 0;
600 for (t = &trace_types; *t; t = &(*t)->next) {
601 len = strlen((*t)->name);
602 if (len > max_tracer_type_len)
603 max_tracer_type_len = len;
606 mutex_unlock(&trace_types_lock);
609 void tracing_reset(struct trace_array *tr, int cpu)
611 ftrace_disable_cpu();
612 ring_buffer_reset_cpu(tr->buffer, cpu);
616 #define SAVED_CMDLINES 128
617 static unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
618 static unsigned map_cmdline_to_pid[SAVED_CMDLINES];
619 static char saved_cmdlines[SAVED_CMDLINES][TASK_COMM_LEN];
620 static int cmdline_idx;
621 static DEFINE_SPINLOCK(trace_cmdline_lock);
623 /* temporary disable recording */
624 atomic_t trace_record_cmdline_disabled __read_mostly;
626 static void trace_init_cmdlines(void)
628 memset(&map_pid_to_cmdline, -1, sizeof(map_pid_to_cmdline));
629 memset(&map_cmdline_to_pid, -1, sizeof(map_cmdline_to_pid));
633 static int trace_stop_count;
634 static DEFINE_SPINLOCK(tracing_start_lock);
637 * tracing_start - quick start of the tracer
639 * If tracing is enabled but was stopped by tracing_stop,
640 * this will start the tracer back up.
642 void tracing_start(void)
644 struct ring_buffer *buffer;
647 if (tracing_disabled)
650 spin_lock_irqsave(&tracing_start_lock, flags);
651 if (--trace_stop_count)
654 if (trace_stop_count < 0) {
655 /* Someone screwed up their debugging */
657 trace_stop_count = 0;
662 buffer = global_trace.buffer;
664 ring_buffer_record_enable(buffer);
666 buffer = max_tr.buffer;
668 ring_buffer_record_enable(buffer);
672 spin_unlock_irqrestore(&tracing_start_lock, flags);
676 * tracing_stop - quick stop of the tracer
678 * Light weight way to stop tracing. Use in conjunction with
681 void tracing_stop(void)
683 struct ring_buffer *buffer;
687 spin_lock_irqsave(&tracing_start_lock, flags);
688 if (trace_stop_count++)
691 buffer = global_trace.buffer;
693 ring_buffer_record_disable(buffer);
695 buffer = max_tr.buffer;
697 ring_buffer_record_disable(buffer);
700 spin_unlock_irqrestore(&tracing_start_lock, flags);
703 void trace_stop_cmdline_recording(void);
705 static void trace_save_cmdline(struct task_struct *tsk)
710 if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT))
714 * It's not the end of the world if we don't get
715 * the lock, but we also don't want to spin
716 * nor do we want to disable interrupts,
717 * so if we miss here, then better luck next time.
719 if (!spin_trylock(&trace_cmdline_lock))
722 idx = map_pid_to_cmdline[tsk->pid];
723 if (idx >= SAVED_CMDLINES) {
724 idx = (cmdline_idx + 1) % SAVED_CMDLINES;
726 map = map_cmdline_to_pid[idx];
727 if (map <= PID_MAX_DEFAULT)
728 map_pid_to_cmdline[map] = (unsigned)-1;
730 map_pid_to_cmdline[tsk->pid] = idx;
735 memcpy(&saved_cmdlines[idx], tsk->comm, TASK_COMM_LEN);
737 spin_unlock(&trace_cmdline_lock);
740 static char *trace_find_cmdline(int pid)
742 char *cmdline = "<...>";
748 if (pid > PID_MAX_DEFAULT)
751 map = map_pid_to_cmdline[pid];
752 if (map >= SAVED_CMDLINES)
755 cmdline = saved_cmdlines[map];
761 void tracing_record_cmdline(struct task_struct *tsk)
763 if (atomic_read(&trace_record_cmdline_disabled))
766 trace_save_cmdline(tsk);
770 tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
773 struct task_struct *tsk = current;
775 entry->preempt_count = pc & 0xff;
776 entry->pid = (tsk) ? tsk->pid : 0;
778 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
779 (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
781 TRACE_FLAG_IRQS_NOSUPPORT |
783 ((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
784 ((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
785 (need_resched() ? TRACE_FLAG_NEED_RESCHED : 0);
789 trace_function(struct trace_array *tr, struct trace_array_cpu *data,
790 unsigned long ip, unsigned long parent_ip, unsigned long flags,
793 struct ring_buffer_event *event;
794 struct ftrace_entry *entry;
795 unsigned long irq_flags;
797 /* If we are reading the ring buffer, don't trace */
798 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
801 event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
805 entry = ring_buffer_event_data(event);
806 tracing_generic_entry_update(&entry->ent, flags, pc);
807 entry->ent.type = TRACE_FN;
809 entry->parent_ip = parent_ip;
810 ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
814 ftrace(struct trace_array *tr, struct trace_array_cpu *data,
815 unsigned long ip, unsigned long parent_ip, unsigned long flags,
818 if (likely(!atomic_read(&data->disabled)))
819 trace_function(tr, data, ip, parent_ip, flags, pc);
822 static void ftrace_trace_stack(struct trace_array *tr,
823 struct trace_array_cpu *data,
827 #ifdef CONFIG_STACKTRACE
828 struct ring_buffer_event *event;
829 struct stack_entry *entry;
830 struct stack_trace trace;
831 unsigned long irq_flags;
833 if (!(trace_flags & TRACE_ITER_STACKTRACE))
836 event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
840 entry = ring_buffer_event_data(event);
841 tracing_generic_entry_update(&entry->ent, flags, pc);
842 entry->ent.type = TRACE_STACK;
844 memset(&entry->caller, 0, sizeof(entry->caller));
846 trace.nr_entries = 0;
847 trace.max_entries = FTRACE_STACK_ENTRIES;
849 trace.entries = entry->caller;
851 save_stack_trace(&trace);
852 ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
856 void __trace_stack(struct trace_array *tr,
857 struct trace_array_cpu *data,
861 ftrace_trace_stack(tr, data, flags, skip, preempt_count());
865 ftrace_trace_special(void *__tr, void *__data,
866 unsigned long arg1, unsigned long arg2, unsigned long arg3,
869 struct ring_buffer_event *event;
870 struct trace_array_cpu *data = __data;
871 struct trace_array *tr = __tr;
872 struct special_entry *entry;
873 unsigned long irq_flags;
875 event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
879 entry = ring_buffer_event_data(event);
880 tracing_generic_entry_update(&entry->ent, 0, pc);
881 entry->ent.type = TRACE_SPECIAL;
885 ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
886 ftrace_trace_stack(tr, data, irq_flags, 4, pc);
892 __trace_special(void *__tr, void *__data,
893 unsigned long arg1, unsigned long arg2, unsigned long arg3)
895 ftrace_trace_special(__tr, __data, arg1, arg2, arg3, preempt_count());
899 tracing_sched_switch_trace(struct trace_array *tr,
900 struct trace_array_cpu *data,
901 struct task_struct *prev,
902 struct task_struct *next,
903 unsigned long flags, int pc)
905 struct ring_buffer_event *event;
906 struct ctx_switch_entry *entry;
907 unsigned long irq_flags;
909 event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
913 entry = ring_buffer_event_data(event);
914 tracing_generic_entry_update(&entry->ent, flags, pc);
915 entry->ent.type = TRACE_CTX;
916 entry->prev_pid = prev->pid;
917 entry->prev_prio = prev->prio;
918 entry->prev_state = prev->state;
919 entry->next_pid = next->pid;
920 entry->next_prio = next->prio;
921 entry->next_state = next->state;
922 entry->next_cpu = task_cpu(next);
923 ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
924 ftrace_trace_stack(tr, data, flags, 5, pc);
928 tracing_sched_wakeup_trace(struct trace_array *tr,
929 struct trace_array_cpu *data,
930 struct task_struct *wakee,
931 struct task_struct *curr,
932 unsigned long flags, int pc)
934 struct ring_buffer_event *event;
935 struct ctx_switch_entry *entry;
936 unsigned long irq_flags;
938 event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
942 entry = ring_buffer_event_data(event);
943 tracing_generic_entry_update(&entry->ent, flags, pc);
944 entry->ent.type = TRACE_WAKE;
945 entry->prev_pid = curr->pid;
946 entry->prev_prio = curr->prio;
947 entry->prev_state = curr->state;
948 entry->next_pid = wakee->pid;
949 entry->next_prio = wakee->prio;
950 entry->next_state = wakee->state;
951 entry->next_cpu = task_cpu(wakee);
952 ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
953 ftrace_trace_stack(tr, data, flags, 6, pc);
959 ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3)
961 struct trace_array *tr = &global_trace;
962 struct trace_array_cpu *data;
967 if (tracing_disabled)
970 pc = preempt_count();
971 local_irq_save(flags);
972 cpu = raw_smp_processor_id();
973 data = tr->data[cpu];
975 if (likely(atomic_inc_return(&data->disabled) == 1))
976 ftrace_trace_special(tr, data, arg1, arg2, arg3, pc);
978 atomic_dec(&data->disabled);
979 local_irq_restore(flags);
982 #ifdef CONFIG_FUNCTION_TRACER
984 function_trace_call_preempt_only(unsigned long ip, unsigned long parent_ip)
986 struct trace_array *tr = &global_trace;
987 struct trace_array_cpu *data;
993 if (unlikely(!ftrace_function_enabled))
996 pc = preempt_count();
997 resched = ftrace_preempt_disable();
998 local_save_flags(flags);
999 cpu = raw_smp_processor_id();
1000 data = tr->data[cpu];
1001 disabled = atomic_inc_return(&data->disabled);
1003 if (likely(disabled == 1))
1004 trace_function(tr, data, ip, parent_ip, flags, pc);
1006 atomic_dec(&data->disabled);
1007 ftrace_preempt_enable(resched);
1011 function_trace_call(unsigned long ip, unsigned long parent_ip)
1013 struct trace_array *tr = &global_trace;
1014 struct trace_array_cpu *data;
1015 unsigned long flags;
1020 if (unlikely(!ftrace_function_enabled))
1024 * Need to use raw, since this must be called before the
1025 * recursive protection is performed.
1027 raw_local_irq_save(flags);
1028 cpu = raw_smp_processor_id();
1029 data = tr->data[cpu];
1030 disabled = atomic_inc_return(&data->disabled);
1032 if (likely(disabled == 1)) {
1033 pc = preempt_count();
1034 trace_function(tr, data, ip, parent_ip, flags, pc);
1037 atomic_dec(&data->disabled);
1038 raw_local_irq_restore(flags);
1041 static struct ftrace_ops trace_ops __read_mostly =
1043 .func = function_trace_call,
1046 void tracing_start_function_trace(void)
1048 ftrace_function_enabled = 0;
1050 if (trace_flags & TRACE_ITER_PREEMPTONLY)
1051 trace_ops.func = function_trace_call_preempt_only;
1053 trace_ops.func = function_trace_call;
1055 register_ftrace_function(&trace_ops);
1056 ftrace_function_enabled = 1;
1059 void tracing_stop_function_trace(void)
1061 ftrace_function_enabled = 0;
1062 unregister_ftrace_function(&trace_ops);
1066 enum trace_file_type {
1067 TRACE_FILE_LAT_FMT = 1,
1070 static void trace_iterator_increment(struct trace_iterator *iter, int cpu)
1072 /* Don't allow ftrace to trace into the ring buffers */
1073 ftrace_disable_cpu();
1076 if (iter->buffer_iter[iter->cpu])
1077 ring_buffer_read(iter->buffer_iter[iter->cpu], NULL);
1079 ftrace_enable_cpu();
1082 static struct trace_entry *
1083 peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts)
1085 struct ring_buffer_event *event;
1086 struct ring_buffer_iter *buf_iter = iter->buffer_iter[cpu];
1088 /* Don't allow ftrace to trace into the ring buffers */
1089 ftrace_disable_cpu();
1092 event = ring_buffer_iter_peek(buf_iter, ts);
1094 event = ring_buffer_peek(iter->tr->buffer, cpu, ts);
1096 ftrace_enable_cpu();
1098 return event ? ring_buffer_event_data(event) : NULL;
1101 static struct trace_entry *
1102 __find_next_entry(struct trace_iterator *iter, int *ent_cpu, u64 *ent_ts)
1104 struct ring_buffer *buffer = iter->tr->buffer;
1105 struct trace_entry *ent, *next = NULL;
1106 u64 next_ts = 0, ts;
1110 for_each_tracing_cpu(cpu) {
1112 if (ring_buffer_empty_cpu(buffer, cpu))
1115 ent = peek_next_entry(iter, cpu, &ts);
1118 * Pick the entry with the smallest timestamp:
1120 if (ent && (!next || ts < next_ts)) {
1128 *ent_cpu = next_cpu;
1136 /* Find the next real entry, without updating the iterator itself */
1137 static struct trace_entry *
1138 find_next_entry(struct trace_iterator *iter, int *ent_cpu, u64 *ent_ts)
1140 return __find_next_entry(iter, ent_cpu, ent_ts);
1143 /* Find the next real entry, and increment the iterator to the next entry */
1144 static void *find_next_entry_inc(struct trace_iterator *iter)
1146 iter->ent = __find_next_entry(iter, &iter->cpu, &iter->ts);
1149 trace_iterator_increment(iter, iter->cpu);
1151 return iter->ent ? iter : NULL;
1154 static void trace_consume(struct trace_iterator *iter)
1156 /* Don't allow ftrace to trace into the ring buffers */
1157 ftrace_disable_cpu();
1158 ring_buffer_consume(iter->tr->buffer, iter->cpu, &iter->ts);
1159 ftrace_enable_cpu();
1162 static void *s_next(struct seq_file *m, void *v, loff_t *pos)
1164 struct trace_iterator *iter = m->private;
1170 /* can't go backwards */
1175 ent = find_next_entry_inc(iter);
1179 while (ent && iter->idx < i)
1180 ent = find_next_entry_inc(iter);
1187 static void *s_start(struct seq_file *m, loff_t *pos)
1189 struct trace_iterator *iter = m->private;
1194 mutex_lock(&trace_types_lock);
1196 if (!current_trace || current_trace != iter->trace) {
1197 mutex_unlock(&trace_types_lock);
1201 atomic_inc(&trace_record_cmdline_disabled);
1203 if (*pos != iter->pos) {
1208 ftrace_disable_cpu();
1210 for_each_tracing_cpu(cpu) {
1211 ring_buffer_iter_reset(iter->buffer_iter[cpu]);
1214 ftrace_enable_cpu();
1216 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
1221 p = s_next(m, p, &l);
1227 static void s_stop(struct seq_file *m, void *p)
1229 atomic_dec(&trace_record_cmdline_disabled);
1230 mutex_unlock(&trace_types_lock);
1233 #ifdef CONFIG_KRETPROBES
1234 static inline const char *kretprobed(const char *name)
1236 static const char tramp_name[] = "kretprobe_trampoline";
1237 int size = sizeof(tramp_name);
1239 if (strncmp(tramp_name, name, size) == 0)
1240 return "[unknown/kretprobe'd]";
1244 static inline const char *kretprobed(const char *name)
1248 #endif /* CONFIG_KRETPROBES */
1251 seq_print_sym_short(struct trace_seq *s, const char *fmt, unsigned long address)
1253 #ifdef CONFIG_KALLSYMS
1254 char str[KSYM_SYMBOL_LEN];
1257 kallsyms_lookup(address, NULL, NULL, NULL, str);
1259 name = kretprobed(str);
1261 return trace_seq_printf(s, fmt, name);
1267 seq_print_sym_offset(struct trace_seq *s, const char *fmt,
1268 unsigned long address)
1270 #ifdef CONFIG_KALLSYMS
1271 char str[KSYM_SYMBOL_LEN];
1274 sprint_symbol(str, address);
1275 name = kretprobed(str);
1277 return trace_seq_printf(s, fmt, name);
1282 #ifndef CONFIG_64BIT
1283 # define IP_FMT "%08lx"
1285 # define IP_FMT "%016lx"
1289 seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags)
1294 return trace_seq_printf(s, "0");
1296 if (sym_flags & TRACE_ITER_SYM_OFFSET)
1297 ret = seq_print_sym_offset(s, "%s", ip);
1299 ret = seq_print_sym_short(s, "%s", ip);
1304 if (sym_flags & TRACE_ITER_SYM_ADDR)
1305 ret = trace_seq_printf(s, " <" IP_FMT ">", ip);
1309 static void print_lat_help_header(struct seq_file *m)
1311 seq_puts(m, "# _------=> CPU# \n");
1312 seq_puts(m, "# / _-----=> irqs-off \n");
1313 seq_puts(m, "# | / _----=> need-resched \n");
1314 seq_puts(m, "# || / _---=> hardirq/softirq \n");
1315 seq_puts(m, "# ||| / _--=> preempt-depth \n");
1316 seq_puts(m, "# |||| / \n");
1317 seq_puts(m, "# ||||| delay \n");
1318 seq_puts(m, "# cmd pid ||||| time | caller \n");
1319 seq_puts(m, "# \\ / ||||| \\ | / \n");
1322 static void print_func_help_header(struct seq_file *m)
1324 seq_puts(m, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
1325 seq_puts(m, "# | | | | |\n");
1330 print_trace_header(struct seq_file *m, struct trace_iterator *iter)
1332 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1333 struct trace_array *tr = iter->tr;
1334 struct trace_array_cpu *data = tr->data[tr->cpu];
1335 struct tracer *type = current_trace;
1336 unsigned long total;
1337 unsigned long entries;
1338 const char *name = "preemption";
1343 entries = ring_buffer_entries(iter->tr->buffer);
1345 ring_buffer_overruns(iter->tr->buffer);
1347 seq_printf(m, "%s latency trace v1.1.5 on %s\n",
1349 seq_puts(m, "-----------------------------------"
1350 "---------------------------------\n");
1351 seq_printf(m, " latency: %lu us, #%lu/%lu, CPU#%d |"
1352 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
1353 nsecs_to_usecs(data->saved_latency),
1357 #if defined(CONFIG_PREEMPT_NONE)
1359 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
1361 #elif defined(CONFIG_PREEMPT)
1366 /* These are reserved for later use */
1369 seq_printf(m, " #P:%d)\n", num_online_cpus());
1373 seq_puts(m, " -----------------\n");
1374 seq_printf(m, " | task: %.16s-%d "
1375 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
1376 data->comm, data->pid, data->uid, data->nice,
1377 data->policy, data->rt_priority);
1378 seq_puts(m, " -----------------\n");
1380 if (data->critical_start) {
1381 seq_puts(m, " => started at: ");
1382 seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
1383 trace_print_seq(m, &iter->seq);
1384 seq_puts(m, "\n => ended at: ");
1385 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
1386 trace_print_seq(m, &iter->seq);
1394 lat_print_generic(struct trace_seq *s, struct trace_entry *entry, int cpu)
1396 int hardirq, softirq;
1399 comm = trace_find_cmdline(entry->pid);
1401 trace_seq_printf(s, "%8.8s-%-5d ", comm, entry->pid);
1402 trace_seq_printf(s, "%3d", cpu);
1403 trace_seq_printf(s, "%c%c",
1404 (entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' :
1405 (entry->flags & TRACE_FLAG_IRQS_NOSUPPORT) ? 'X' : '.',
1406 ((entry->flags & TRACE_FLAG_NEED_RESCHED) ? 'N' : '.'));
1408 hardirq = entry->flags & TRACE_FLAG_HARDIRQ;
1409 softirq = entry->flags & TRACE_FLAG_SOFTIRQ;
1410 if (hardirq && softirq) {
1411 trace_seq_putc(s, 'H');
1414 trace_seq_putc(s, 'h');
1417 trace_seq_putc(s, 's');
1419 trace_seq_putc(s, '.');
1423 if (entry->preempt_count)
1424 trace_seq_printf(s, "%x", entry->preempt_count);
1426 trace_seq_puts(s, ".");
1429 unsigned long preempt_mark_thresh = 100;
1432 lat_print_timestamp(struct trace_seq *s, u64 abs_usecs,
1433 unsigned long rel_usecs)
1435 trace_seq_printf(s, " %4lldus", abs_usecs);
1436 if (rel_usecs > preempt_mark_thresh)
1437 trace_seq_puts(s, "!: ");
1438 else if (rel_usecs > 1)
1439 trace_seq_puts(s, "+: ");
1441 trace_seq_puts(s, " : ");
1444 static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;
1447 * The message is supposed to contain an ending newline.
1448 * If the printing stops prematurely, try to add a newline of our own.
1450 void trace_seq_print_cont(struct trace_seq *s, struct trace_iterator *iter)
1452 struct trace_entry *ent;
1453 struct trace_field_cont *cont;
1456 ent = peek_next_entry(iter, iter->cpu, NULL);
1457 if (!ent || ent->type != TRACE_CONT) {
1458 trace_seq_putc(s, '\n');
1463 cont = (struct trace_field_cont *)ent;
1465 ok = (trace_seq_printf(s, "%s", cont->buf) > 0);
1467 ftrace_disable_cpu();
1469 if (iter->buffer_iter[iter->cpu])
1470 ring_buffer_read(iter->buffer_iter[iter->cpu], NULL);
1472 ring_buffer_consume(iter->tr->buffer, iter->cpu, NULL);
1474 ftrace_enable_cpu();
1476 ent = peek_next_entry(iter, iter->cpu, NULL);
1477 } while (ent && ent->type == TRACE_CONT);
1480 trace_seq_putc(s, '\n');
1483 static void test_cpu_buff_start(struct trace_iterator *iter)
1485 struct trace_seq *s = &iter->seq;
1487 if (cpu_isset(iter->cpu, iter->started))
1490 cpu_set(iter->cpu, iter->started);
1491 trace_seq_printf(s, "##### CPU %u buffer started ####\n", iter->cpu);
1494 static enum print_line_t
1495 print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu)
1497 struct trace_seq *s = &iter->seq;
1498 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1499 struct trace_entry *next_entry;
1500 unsigned long verbose = (trace_flags & TRACE_ITER_VERBOSE);
1501 struct trace_entry *entry = iter->ent;
1502 unsigned long abs_usecs;
1503 unsigned long rel_usecs;
1510 if (entry->type == TRACE_CONT)
1511 return TRACE_TYPE_HANDLED;
1513 test_cpu_buff_start(iter);
1515 next_entry = find_next_entry(iter, NULL, &next_ts);
1518 rel_usecs = ns2usecs(next_ts - iter->ts);
1519 abs_usecs = ns2usecs(iter->ts - iter->tr->time_start);
1522 comm = trace_find_cmdline(entry->pid);
1523 trace_seq_printf(s, "%16s %5d %3d %d %08x %08x [%08lx]"
1524 " %ld.%03ldms (+%ld.%03ldms): ",
1526 entry->pid, cpu, entry->flags,
1527 entry->preempt_count, trace_idx,
1530 abs_usecs % 1000, rel_usecs/1000,
1533 lat_print_generic(s, entry, cpu);
1534 lat_print_timestamp(s, abs_usecs, rel_usecs);
1536 switch (entry->type) {
1538 struct ftrace_entry *field;
1540 trace_assign_type(field, entry);
1542 seq_print_ip_sym(s, field->ip, sym_flags);
1543 trace_seq_puts(s, " (");
1544 seq_print_ip_sym(s, field->parent_ip, sym_flags);
1545 trace_seq_puts(s, ")\n");
1550 struct ctx_switch_entry *field;
1552 trace_assign_type(field, entry);
1554 T = field->next_state < sizeof(state_to_char) ?
1555 state_to_char[field->next_state] : 'X';
1557 state = field->prev_state ?
1558 __ffs(field->prev_state) + 1 : 0;
1559 S = state < sizeof(state_to_char) - 1 ? state_to_char[state] : 'X';
1560 comm = trace_find_cmdline(field->next_pid);
1561 trace_seq_printf(s, " %5d:%3d:%c %s [%03d] %5d:%3d:%c %s\n",
1564 S, entry->type == TRACE_CTX ? "==>" : " +",
1571 case TRACE_SPECIAL: {
1572 struct special_entry *field;
1574 trace_assign_type(field, entry);
1576 trace_seq_printf(s, "# %ld %ld %ld\n",
1583 struct stack_entry *field;
1585 trace_assign_type(field, entry);
1587 for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
1589 trace_seq_puts(s, " <= ");
1590 seq_print_ip_sym(s, field->caller[i], sym_flags);
1592 trace_seq_puts(s, "\n");
1596 struct print_entry *field;
1598 trace_assign_type(field, entry);
1600 seq_print_ip_sym(s, field->ip, sym_flags);
1601 trace_seq_printf(s, ": %s", field->buf);
1602 if (entry->flags & TRACE_FLAG_CONT)
1603 trace_seq_print_cont(s, iter);
1607 trace_seq_printf(s, "Unknown type %d\n", entry->type);
1609 return TRACE_TYPE_HANDLED;
1612 static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
1614 struct trace_seq *s = &iter->seq;
1615 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1616 struct trace_entry *entry;
1617 unsigned long usec_rem;
1618 unsigned long long t;
1627 if (entry->type == TRACE_CONT)
1628 return TRACE_TYPE_HANDLED;
1630 test_cpu_buff_start(iter);
1632 comm = trace_find_cmdline(iter->ent->pid);
1634 t = ns2usecs(iter->ts);
1635 usec_rem = do_div(t, 1000000ULL);
1636 secs = (unsigned long)t;
1638 ret = trace_seq_printf(s, "%16s-%-5d ", comm, entry->pid);
1640 return TRACE_TYPE_PARTIAL_LINE;
1641 ret = trace_seq_printf(s, "[%03d] ", iter->cpu);
1643 return TRACE_TYPE_PARTIAL_LINE;
1644 ret = trace_seq_printf(s, "%5lu.%06lu: ", secs, usec_rem);
1646 return TRACE_TYPE_PARTIAL_LINE;
1648 switch (entry->type) {
1650 struct ftrace_entry *field;
1652 trace_assign_type(field, entry);
1654 ret = seq_print_ip_sym(s, field->ip, sym_flags);
1656 return TRACE_TYPE_PARTIAL_LINE;
1657 if ((sym_flags & TRACE_ITER_PRINT_PARENT) &&
1659 ret = trace_seq_printf(s, " <-");
1661 return TRACE_TYPE_PARTIAL_LINE;
1662 ret = seq_print_ip_sym(s,
1666 return TRACE_TYPE_PARTIAL_LINE;
1668 ret = trace_seq_printf(s, "\n");
1670 return TRACE_TYPE_PARTIAL_LINE;
1675 struct ctx_switch_entry *field;
1677 trace_assign_type(field, entry);
1679 S = field->prev_state < sizeof(state_to_char) ?
1680 state_to_char[field->prev_state] : 'X';
1681 T = field->next_state < sizeof(state_to_char) ?
1682 state_to_char[field->next_state] : 'X';
1683 ret = trace_seq_printf(s, " %5d:%3d:%c %s [%03d] %5d:%3d:%c\n",
1687 entry->type == TRACE_CTX ? "==>" : " +",
1693 return TRACE_TYPE_PARTIAL_LINE;
1696 case TRACE_SPECIAL: {
1697 struct special_entry *field;
1699 trace_assign_type(field, entry);
1701 ret = trace_seq_printf(s, "# %ld %ld %ld\n",
1706 return TRACE_TYPE_PARTIAL_LINE;
1710 struct stack_entry *field;
1712 trace_assign_type(field, entry);
1714 for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
1716 ret = trace_seq_puts(s, " <= ");
1718 return TRACE_TYPE_PARTIAL_LINE;
1720 ret = seq_print_ip_sym(s, field->caller[i],
1723 return TRACE_TYPE_PARTIAL_LINE;
1725 ret = trace_seq_puts(s, "\n");
1727 return TRACE_TYPE_PARTIAL_LINE;
1731 struct print_entry *field;
1733 trace_assign_type(field, entry);
1735 seq_print_ip_sym(s, field->ip, sym_flags);
1736 trace_seq_printf(s, ": %s", field->buf);
1737 if (entry->flags & TRACE_FLAG_CONT)
1738 trace_seq_print_cont(s, iter);
1742 return TRACE_TYPE_HANDLED;
1745 static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
1747 struct trace_seq *s = &iter->seq;
1748 struct trace_entry *entry;
1754 if (entry->type == TRACE_CONT)
1755 return TRACE_TYPE_HANDLED;
1757 ret = trace_seq_printf(s, "%d %d %llu ",
1758 entry->pid, iter->cpu, iter->ts);
1760 return TRACE_TYPE_PARTIAL_LINE;
1762 switch (entry->type) {
1764 struct ftrace_entry *field;
1766 trace_assign_type(field, entry);
1768 ret = trace_seq_printf(s, "%x %x\n",
1772 return TRACE_TYPE_PARTIAL_LINE;
1777 struct ctx_switch_entry *field;
1779 trace_assign_type(field, entry);
1781 S = field->prev_state < sizeof(state_to_char) ?
1782 state_to_char[field->prev_state] : 'X';
1783 T = field->next_state < sizeof(state_to_char) ?
1784 state_to_char[field->next_state] : 'X';
1785 if (entry->type == TRACE_WAKE)
1787 ret = trace_seq_printf(s, "%d %d %c %d %d %d %c\n",
1796 return TRACE_TYPE_PARTIAL_LINE;
1801 struct special_entry *field;
1803 trace_assign_type(field, entry);
1805 ret = trace_seq_printf(s, "# %ld %ld %ld\n",
1810 return TRACE_TYPE_PARTIAL_LINE;
1814 struct print_entry *field;
1816 trace_assign_type(field, entry);
1818 trace_seq_printf(s, "# %lx %s", field->ip, field->buf);
1819 if (entry->flags & TRACE_FLAG_CONT)
1820 trace_seq_print_cont(s, iter);
1824 return TRACE_TYPE_HANDLED;
1827 #define SEQ_PUT_FIELD_RET(s, x) \
1829 if (!trace_seq_putmem(s, &(x), sizeof(x))) \
1833 #define SEQ_PUT_HEX_FIELD_RET(s, x) \
1835 BUILD_BUG_ON(sizeof(x) > MAX_MEMHEX_BYTES); \
1836 if (!trace_seq_putmem_hex(s, &(x), sizeof(x))) \
1840 static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
1842 struct trace_seq *s = &iter->seq;
1843 unsigned char newline = '\n';
1844 struct trace_entry *entry;
1849 if (entry->type == TRACE_CONT)
1850 return TRACE_TYPE_HANDLED;
1852 SEQ_PUT_HEX_FIELD_RET(s, entry->pid);
1853 SEQ_PUT_HEX_FIELD_RET(s, iter->cpu);
1854 SEQ_PUT_HEX_FIELD_RET(s, iter->ts);
1856 switch (entry->type) {
1858 struct ftrace_entry *field;
1860 trace_assign_type(field, entry);
1862 SEQ_PUT_HEX_FIELD_RET(s, field->ip);
1863 SEQ_PUT_HEX_FIELD_RET(s, field->parent_ip);
1868 struct ctx_switch_entry *field;
1870 trace_assign_type(field, entry);
1872 S = field->prev_state < sizeof(state_to_char) ?
1873 state_to_char[field->prev_state] : 'X';
1874 T = field->next_state < sizeof(state_to_char) ?
1875 state_to_char[field->next_state] : 'X';
1876 if (entry->type == TRACE_WAKE)
1878 SEQ_PUT_HEX_FIELD_RET(s, field->prev_pid);
1879 SEQ_PUT_HEX_FIELD_RET(s, field->prev_prio);
1880 SEQ_PUT_HEX_FIELD_RET(s, S);
1881 SEQ_PUT_HEX_FIELD_RET(s, field->next_cpu);
1882 SEQ_PUT_HEX_FIELD_RET(s, field->next_pid);
1883 SEQ_PUT_HEX_FIELD_RET(s, field->next_prio);
1884 SEQ_PUT_HEX_FIELD_RET(s, T);
1889 struct special_entry *field;
1891 trace_assign_type(field, entry);
1893 SEQ_PUT_HEX_FIELD_RET(s, field->arg1);
1894 SEQ_PUT_HEX_FIELD_RET(s, field->arg2);
1895 SEQ_PUT_HEX_FIELD_RET(s, field->arg3);
1899 SEQ_PUT_FIELD_RET(s, newline);
1901 return TRACE_TYPE_HANDLED;
1904 static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
1906 struct trace_seq *s = &iter->seq;
1907 struct trace_entry *entry;
1911 if (entry->type == TRACE_CONT)
1912 return TRACE_TYPE_HANDLED;
1914 SEQ_PUT_FIELD_RET(s, entry->pid);
1915 SEQ_PUT_FIELD_RET(s, entry->cpu);
1916 SEQ_PUT_FIELD_RET(s, iter->ts);
1918 switch (entry->type) {
1920 struct ftrace_entry *field;
1922 trace_assign_type(field, entry);
1924 SEQ_PUT_FIELD_RET(s, field->ip);
1925 SEQ_PUT_FIELD_RET(s, field->parent_ip);
1929 struct ctx_switch_entry *field;
1931 trace_assign_type(field, entry);
1933 SEQ_PUT_FIELD_RET(s, field->prev_pid);
1934 SEQ_PUT_FIELD_RET(s, field->prev_prio);
1935 SEQ_PUT_FIELD_RET(s, field->prev_state);
1936 SEQ_PUT_FIELD_RET(s, field->next_pid);
1937 SEQ_PUT_FIELD_RET(s, field->next_prio);
1938 SEQ_PUT_FIELD_RET(s, field->next_state);
1943 struct special_entry *field;
1945 trace_assign_type(field, entry);
1947 SEQ_PUT_FIELD_RET(s, field->arg1);
1948 SEQ_PUT_FIELD_RET(s, field->arg2);
1949 SEQ_PUT_FIELD_RET(s, field->arg3);
1956 static int trace_empty(struct trace_iterator *iter)
1960 for_each_tracing_cpu(cpu) {
1961 if (iter->buffer_iter[cpu]) {
1962 if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
1965 if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu))
1973 static enum print_line_t print_trace_line(struct trace_iterator *iter)
1975 enum print_line_t ret;
1977 if (iter->trace && iter->trace->print_line) {
1978 ret = iter->trace->print_line(iter);
1979 if (ret != TRACE_TYPE_UNHANDLED)
1983 if (trace_flags & TRACE_ITER_BIN)
1984 return print_bin_fmt(iter);
1986 if (trace_flags & TRACE_ITER_HEX)
1987 return print_hex_fmt(iter);
1989 if (trace_flags & TRACE_ITER_RAW)
1990 return print_raw_fmt(iter);
1992 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
1993 return print_lat_fmt(iter, iter->idx, iter->cpu);
1995 return print_trace_fmt(iter);
1998 static int s_show(struct seq_file *m, void *v)
2000 struct trace_iterator *iter = v;
2002 if (iter->ent == NULL) {
2004 seq_printf(m, "# tracer: %s\n", iter->trace->name);
2007 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
2008 /* print nothing if the buffers are empty */
2009 if (trace_empty(iter))
2011 print_trace_header(m, iter);
2012 if (!(trace_flags & TRACE_ITER_VERBOSE))
2013 print_lat_help_header(m);
2015 if (!(trace_flags & TRACE_ITER_VERBOSE))
2016 print_func_help_header(m);
2019 print_trace_line(iter);
2020 trace_print_seq(m, &iter->seq);
2026 static struct seq_operations tracer_seq_ops = {
2033 static struct trace_iterator *
2034 __tracing_open(struct inode *inode, struct file *file, int *ret)
2036 struct trace_iterator *iter;
2040 if (tracing_disabled) {
2045 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2051 mutex_lock(&trace_types_lock);
2052 if (current_trace && current_trace->print_max)
2055 iter->tr = inode->i_private;
2056 iter->trace = current_trace;
2059 for_each_tracing_cpu(cpu) {
2061 iter->buffer_iter[cpu] =
2062 ring_buffer_read_start(iter->tr->buffer, cpu);
2064 if (!iter->buffer_iter[cpu])
2068 /* TODO stop tracer */
2069 *ret = seq_open(file, &tracer_seq_ops);
2073 m = file->private_data;
2076 /* stop the trace while dumping */
2079 if (iter->trace && iter->trace->open)
2080 iter->trace->open(iter);
2082 mutex_unlock(&trace_types_lock);
2088 for_each_tracing_cpu(cpu) {
2089 if (iter->buffer_iter[cpu])
2090 ring_buffer_read_finish(iter->buffer_iter[cpu]);
2092 mutex_unlock(&trace_types_lock);
2094 return ERR_PTR(-ENOMEM);
2097 int tracing_open_generic(struct inode *inode, struct file *filp)
2099 if (tracing_disabled)
2102 filp->private_data = inode->i_private;
2106 int tracing_release(struct inode *inode, struct file *file)
2108 struct seq_file *m = (struct seq_file *)file->private_data;
2109 struct trace_iterator *iter = m->private;
2112 mutex_lock(&trace_types_lock);
2113 for_each_tracing_cpu(cpu) {
2114 if (iter->buffer_iter[cpu])
2115 ring_buffer_read_finish(iter->buffer_iter[cpu]);
2118 if (iter->trace && iter->trace->close)
2119 iter->trace->close(iter);
2121 /* reenable tracing if it was previously enabled */
2123 mutex_unlock(&trace_types_lock);
2125 seq_release(inode, file);
2130 static int tracing_open(struct inode *inode, struct file *file)
2134 __tracing_open(inode, file, &ret);
2139 static int tracing_lt_open(struct inode *inode, struct file *file)
2141 struct trace_iterator *iter;
2144 iter = __tracing_open(inode, file, &ret);
2147 iter->iter_flags |= TRACE_FILE_LAT_FMT;
2154 t_next(struct seq_file *m, void *v, loff_t *pos)
2156 struct tracer *t = m->private;
2168 static void *t_start(struct seq_file *m, loff_t *pos)
2170 struct tracer *t = m->private;
2173 mutex_lock(&trace_types_lock);
2174 for (; t && l < *pos; t = t_next(m, t, &l))
2180 static void t_stop(struct seq_file *m, void *p)
2182 mutex_unlock(&trace_types_lock);
2185 static int t_show(struct seq_file *m, void *v)
2187 struct tracer *t = v;
2192 seq_printf(m, "%s", t->name);
2201 static struct seq_operations show_traces_seq_ops = {
2208 static int show_traces_open(struct inode *inode, struct file *file)
2212 if (tracing_disabled)
2215 ret = seq_open(file, &show_traces_seq_ops);
2217 struct seq_file *m = file->private_data;
2218 m->private = trace_types;
2224 static struct file_operations tracing_fops = {
2225 .open = tracing_open,
2227 .llseek = seq_lseek,
2228 .release = tracing_release,
2231 static struct file_operations tracing_lt_fops = {
2232 .open = tracing_lt_open,
2234 .llseek = seq_lseek,
2235 .release = tracing_release,
2238 static struct file_operations show_traces_fops = {
2239 .open = show_traces_open,
2241 .release = seq_release,
2245 * Only trace on a CPU if the bitmask is set:
2247 static cpumask_t tracing_cpumask = CPU_MASK_ALL;
2250 * When tracing/tracing_cpu_mask is modified then this holds
2251 * the new bitmask we are about to install:
2253 static cpumask_t tracing_cpumask_new;
2256 * The tracer itself will not take this lock, but still we want
2257 * to provide a consistent cpumask to user-space:
2259 static DEFINE_MUTEX(tracing_cpumask_update_lock);
2262 * Temporary storage for the character representation of the
2263 * CPU bitmask (and one more byte for the newline):
2265 static char mask_str[NR_CPUS + 1];
2268 tracing_cpumask_read(struct file *filp, char __user *ubuf,
2269 size_t count, loff_t *ppos)
2273 mutex_lock(&tracing_cpumask_update_lock);
2275 len = cpumask_scnprintf(mask_str, count, tracing_cpumask);
2276 if (count - len < 2) {
2280 len += sprintf(mask_str + len, "\n");
2281 count = simple_read_from_buffer(ubuf, count, ppos, mask_str, NR_CPUS+1);
2284 mutex_unlock(&tracing_cpumask_update_lock);
2290 tracing_cpumask_write(struct file *filp, const char __user *ubuf,
2291 size_t count, loff_t *ppos)
2295 mutex_lock(&tracing_cpumask_update_lock);
2296 err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
2300 raw_local_irq_disable();
2301 __raw_spin_lock(&ftrace_max_lock);
2302 for_each_tracing_cpu(cpu) {
2304 * Increase/decrease the disabled counter if we are
2305 * about to flip a bit in the cpumask:
2307 if (cpu_isset(cpu, tracing_cpumask) &&
2308 !cpu_isset(cpu, tracing_cpumask_new)) {
2309 atomic_inc(&global_trace.data[cpu]->disabled);
2311 if (!cpu_isset(cpu, tracing_cpumask) &&
2312 cpu_isset(cpu, tracing_cpumask_new)) {
2313 atomic_dec(&global_trace.data[cpu]->disabled);
2316 __raw_spin_unlock(&ftrace_max_lock);
2317 raw_local_irq_enable();
2319 tracing_cpumask = tracing_cpumask_new;
2321 mutex_unlock(&tracing_cpumask_update_lock);
2326 mutex_unlock(&tracing_cpumask_update_lock);
2331 static struct file_operations tracing_cpumask_fops = {
2332 .open = tracing_open_generic,
2333 .read = tracing_cpumask_read,
2334 .write = tracing_cpumask_write,
2338 tracing_iter_ctrl_read(struct file *filp, char __user *ubuf,
2339 size_t cnt, loff_t *ppos)
2346 /* calulate max size */
2347 for (i = 0; trace_options[i]; i++) {
2348 len += strlen(trace_options[i]);
2349 len += 3; /* "no" and space */
2352 /* +2 for \n and \0 */
2353 buf = kmalloc(len + 2, GFP_KERNEL);
2357 for (i = 0; trace_options[i]; i++) {
2358 if (trace_flags & (1 << i))
2359 r += sprintf(buf + r, "%s ", trace_options[i]);
2361 r += sprintf(buf + r, "no%s ", trace_options[i]);
2364 r += sprintf(buf + r, "\n");
2365 WARN_ON(r >= len + 2);
2367 r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2375 tracing_iter_ctrl_write(struct file *filp, const char __user *ubuf,
2376 size_t cnt, loff_t *ppos)
2383 if (cnt >= sizeof(buf))
2386 if (copy_from_user(&buf, ubuf, cnt))
2391 if (strncmp(buf, "no", 2) == 0) {
2396 for (i = 0; trace_options[i]; i++) {
2397 int len = strlen(trace_options[i]);
2399 if (strncmp(cmp, trace_options[i], len) == 0) {
2401 trace_flags &= ~(1 << i);
2403 trace_flags |= (1 << i);
2408 * If no option could be set, return an error:
2410 if (!trace_options[i])
2418 static struct file_operations tracing_iter_fops = {
2419 .open = tracing_open_generic,
2420 .read = tracing_iter_ctrl_read,
2421 .write = tracing_iter_ctrl_write,
2424 static const char readme_msg[] =
2425 "tracing mini-HOWTO:\n\n"
2427 "# mount -t debugfs nodev /debug\n\n"
2428 "# cat /debug/tracing/available_tracers\n"
2429 "wakeup preemptirqsoff preemptoff irqsoff ftrace sched_switch none\n\n"
2430 "# cat /debug/tracing/current_tracer\n"
2432 "# echo sched_switch > /debug/tracing/current_tracer\n"
2433 "# cat /debug/tracing/current_tracer\n"
2435 "# cat /debug/tracing/iter_ctrl\n"
2436 "noprint-parent nosym-offset nosym-addr noverbose\n"
2437 "# echo print-parent > /debug/tracing/iter_ctrl\n"
2438 "# echo 1 > /debug/tracing/tracing_enabled\n"
2439 "# cat /debug/tracing/trace > /tmp/trace.txt\n"
2440 "echo 0 > /debug/tracing/tracing_enabled\n"
2444 tracing_readme_read(struct file *filp, char __user *ubuf,
2445 size_t cnt, loff_t *ppos)
2447 return simple_read_from_buffer(ubuf, cnt, ppos,
2448 readme_msg, strlen(readme_msg));
2451 static struct file_operations tracing_readme_fops = {
2452 .open = tracing_open_generic,
2453 .read = tracing_readme_read,
2457 tracing_ctrl_read(struct file *filp, char __user *ubuf,
2458 size_t cnt, loff_t *ppos)
2463 r = sprintf(buf, "%u\n", tracer_enabled);
2464 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2468 tracing_ctrl_write(struct file *filp, const char __user *ubuf,
2469 size_t cnt, loff_t *ppos)
2471 struct trace_array *tr = filp->private_data;
2476 if (cnt >= sizeof(buf))
2479 if (copy_from_user(&buf, ubuf, cnt))
2484 ret = strict_strtoul(buf, 10, &val);
2490 mutex_lock(&trace_types_lock);
2491 if (tracer_enabled ^ val) {
2494 if (current_trace->start)
2495 current_trace->start(tr);
2500 if (current_trace->stop)
2501 current_trace->stop(tr);
2504 mutex_unlock(&trace_types_lock);
2512 tracing_set_trace_read(struct file *filp, char __user *ubuf,
2513 size_t cnt, loff_t *ppos)
2515 char buf[max_tracer_type_len+2];
2518 mutex_lock(&trace_types_lock);
2520 r = sprintf(buf, "%s\n", current_trace->name);
2522 r = sprintf(buf, "\n");
2523 mutex_unlock(&trace_types_lock);
2525 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2528 static int tracing_set_tracer(char *buf)
2530 struct trace_array *tr = &global_trace;
2534 mutex_lock(&trace_types_lock);
2535 for (t = trace_types; t; t = t->next) {
2536 if (strcmp(t->name, buf) == 0)
2543 if (t == current_trace)
2546 if (current_trace && current_trace->reset)
2547 current_trace->reset(tr);
2554 mutex_unlock(&trace_types_lock);
2560 tracing_set_trace_write(struct file *filp, const char __user *ubuf,
2561 size_t cnt, loff_t *ppos)
2563 char buf[max_tracer_type_len+1];
2567 if (cnt > max_tracer_type_len)
2568 cnt = max_tracer_type_len;
2570 if (copy_from_user(&buf, ubuf, cnt))
2575 /* strip ending whitespace. */
2576 for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
2579 ret = tracing_set_tracer(buf);
2590 tracing_max_lat_read(struct file *filp, char __user *ubuf,
2591 size_t cnt, loff_t *ppos)
2593 unsigned long *ptr = filp->private_data;
2597 r = snprintf(buf, sizeof(buf), "%ld\n",
2598 *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
2599 if (r > sizeof(buf))
2601 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2605 tracing_max_lat_write(struct file *filp, const char __user *ubuf,
2606 size_t cnt, loff_t *ppos)
2608 long *ptr = filp->private_data;
2613 if (cnt >= sizeof(buf))
2616 if (copy_from_user(&buf, ubuf, cnt))
2621 ret = strict_strtoul(buf, 10, &val);
2630 static atomic_t tracing_reader;
2632 static int tracing_open_pipe(struct inode *inode, struct file *filp)
2634 struct trace_iterator *iter;
2636 if (tracing_disabled)
2639 /* We only allow for reader of the pipe */
2640 if (atomic_inc_return(&tracing_reader) != 1) {
2641 atomic_dec(&tracing_reader);
2645 /* create a buffer to store the information to pass to userspace */
2646 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2650 mutex_lock(&trace_types_lock);
2652 /* trace pipe does not show start of buffer */
2653 cpus_setall(iter->started);
2655 iter->tr = &global_trace;
2656 iter->trace = current_trace;
2657 filp->private_data = iter;
2659 if (iter->trace->pipe_open)
2660 iter->trace->pipe_open(iter);
2661 mutex_unlock(&trace_types_lock);
2666 static int tracing_release_pipe(struct inode *inode, struct file *file)
2668 struct trace_iterator *iter = file->private_data;
2671 atomic_dec(&tracing_reader);
2677 tracing_poll_pipe(struct file *filp, poll_table *poll_table)
2679 struct trace_iterator *iter = filp->private_data;
2681 if (trace_flags & TRACE_ITER_BLOCK) {
2683 * Always select as readable when in blocking mode
2685 return POLLIN | POLLRDNORM;
2687 if (!trace_empty(iter))
2688 return POLLIN | POLLRDNORM;
2689 poll_wait(filp, &trace_wait, poll_table);
2690 if (!trace_empty(iter))
2691 return POLLIN | POLLRDNORM;
2701 tracing_read_pipe(struct file *filp, char __user *ubuf,
2702 size_t cnt, loff_t *ppos)
2704 struct trace_iterator *iter = filp->private_data;
2707 /* return any leftover data */
2708 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
2712 trace_seq_reset(&iter->seq);
2714 mutex_lock(&trace_types_lock);
2715 if (iter->trace->read) {
2716 sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
2723 while (trace_empty(iter)) {
2725 if ((filp->f_flags & O_NONBLOCK)) {
2731 * This is a make-shift waitqueue. The reason we don't use
2732 * an actual wait queue is because:
2733 * 1) we only ever have one waiter
2734 * 2) the tracing, traces all functions, we don't want
2735 * the overhead of calling wake_up and friends
2736 * (and tracing them too)
2737 * Anyway, this is really very primitive wakeup.
2739 set_current_state(TASK_INTERRUPTIBLE);
2740 iter->tr->waiter = current;
2742 mutex_unlock(&trace_types_lock);
2744 /* sleep for 100 msecs, and try again. */
2745 schedule_timeout(HZ/10);
2747 mutex_lock(&trace_types_lock);
2749 iter->tr->waiter = NULL;
2751 if (signal_pending(current)) {
2756 if (iter->trace != current_trace)
2760 * We block until we read something and tracing is disabled.
2761 * We still block if tracing is disabled, but we have never
2762 * read anything. This allows a user to cat this file, and
2763 * then enable tracing. But after we have read something,
2764 * we give an EOF when tracing is again disabled.
2766 * iter->pos will be 0 if we haven't read anything.
2768 if (!tracer_enabled && iter->pos)
2774 /* stop when tracing is finished */
2775 if (trace_empty(iter))
2778 if (cnt >= PAGE_SIZE)
2779 cnt = PAGE_SIZE - 1;
2781 /* reset all but tr, trace, and overruns */
2782 memset(&iter->seq, 0,
2783 sizeof(struct trace_iterator) -
2784 offsetof(struct trace_iterator, seq));
2787 while (find_next_entry_inc(iter) != NULL) {
2788 enum print_line_t ret;
2789 int len = iter->seq.len;
2791 ret = print_trace_line(iter);
2792 if (ret == TRACE_TYPE_PARTIAL_LINE) {
2793 /* don't print partial lines */
2794 iter->seq.len = len;
2798 trace_consume(iter);
2800 if (iter->seq.len >= cnt)
2804 /* Now copy what we have to the user */
2805 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
2806 if (iter->seq.readpos >= iter->seq.len)
2807 trace_seq_reset(&iter->seq);
2810 * If there was nothing to send to user, inspite of consuming trace
2811 * entries, go back to wait for more entries.
2817 mutex_unlock(&trace_types_lock);
2823 tracing_entries_read(struct file *filp, char __user *ubuf,
2824 size_t cnt, loff_t *ppos)
2826 struct trace_array *tr = filp->private_data;
2830 r = sprintf(buf, "%lu\n", tr->entries);
2831 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2835 tracing_entries_write(struct file *filp, const char __user *ubuf,
2836 size_t cnt, loff_t *ppos)
2842 if (cnt >= sizeof(buf))
2845 if (copy_from_user(&buf, ubuf, cnt))
2850 ret = strict_strtoul(buf, 10, &val);
2854 /* must have at least 1 entry */
2858 mutex_lock(&trace_types_lock);
2862 /* disable all cpu buffers */
2863 for_each_tracing_cpu(cpu) {
2864 if (global_trace.data[cpu])
2865 atomic_inc(&global_trace.data[cpu]->disabled);
2866 if (max_tr.data[cpu])
2867 atomic_inc(&max_tr.data[cpu]->disabled);
2870 if (val != global_trace.entries) {
2871 ret = ring_buffer_resize(global_trace.buffer, val);
2877 ret = ring_buffer_resize(max_tr.buffer, val);
2881 r = ring_buffer_resize(global_trace.buffer,
2882 global_trace.entries);
2884 /* AARGH! We are left with different
2885 * size max buffer!!!! */
2887 tracing_disabled = 1;
2892 global_trace.entries = val;
2897 /* If check pages failed, return ENOMEM */
2898 if (tracing_disabled)
2901 for_each_tracing_cpu(cpu) {
2902 if (global_trace.data[cpu])
2903 atomic_dec(&global_trace.data[cpu]->disabled);
2904 if (max_tr.data[cpu])
2905 atomic_dec(&max_tr.data[cpu]->disabled);
2909 max_tr.entries = global_trace.entries;
2910 mutex_unlock(&trace_types_lock);
2915 static int mark_printk(const char *fmt, ...)
2919 va_start(args, fmt);
2920 ret = trace_vprintk(0, fmt, args);
2926 tracing_mark_write(struct file *filp, const char __user *ubuf,
2927 size_t cnt, loff_t *fpos)
2932 if (tracing_disabled)
2935 if (cnt > TRACE_BUF_SIZE)
2936 cnt = TRACE_BUF_SIZE;
2938 buf = kmalloc(cnt + 1, GFP_KERNEL);
2942 if (copy_from_user(buf, ubuf, cnt)) {
2947 /* Cut from the first nil or newline. */
2949 end = strchr(buf, '\n');
2953 cnt = mark_printk("%s\n", buf);
2960 static struct file_operations tracing_max_lat_fops = {
2961 .open = tracing_open_generic,
2962 .read = tracing_max_lat_read,
2963 .write = tracing_max_lat_write,
2966 static struct file_operations tracing_ctrl_fops = {
2967 .open = tracing_open_generic,
2968 .read = tracing_ctrl_read,
2969 .write = tracing_ctrl_write,
2972 static struct file_operations set_tracer_fops = {
2973 .open = tracing_open_generic,
2974 .read = tracing_set_trace_read,
2975 .write = tracing_set_trace_write,
2978 static struct file_operations tracing_pipe_fops = {
2979 .open = tracing_open_pipe,
2980 .poll = tracing_poll_pipe,
2981 .read = tracing_read_pipe,
2982 .release = tracing_release_pipe,
2985 static struct file_operations tracing_entries_fops = {
2986 .open = tracing_open_generic,
2987 .read = tracing_entries_read,
2988 .write = tracing_entries_write,
2991 static struct file_operations tracing_mark_fops = {
2992 .open = tracing_open_generic,
2993 .write = tracing_mark_write,
2996 #ifdef CONFIG_DYNAMIC_FTRACE
2998 int __weak ftrace_arch_read_dyn_info(char *buf, int size)
3004 tracing_read_dyn_info(struct file *filp, char __user *ubuf,
3005 size_t cnt, loff_t *ppos)
3007 static char ftrace_dyn_info_buffer[1024];
3008 static DEFINE_MUTEX(dyn_info_mutex);
3009 unsigned long *p = filp->private_data;
3010 char *buf = ftrace_dyn_info_buffer;
3011 int size = ARRAY_SIZE(ftrace_dyn_info_buffer);
3014 mutex_lock(&dyn_info_mutex);
3015 r = sprintf(buf, "%ld ", *p);
3017 r += ftrace_arch_read_dyn_info(buf+r, (size-1)-r);
3020 r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
3022 mutex_unlock(&dyn_info_mutex);
3027 static struct file_operations tracing_dyn_info_fops = {
3028 .open = tracing_open_generic,
3029 .read = tracing_read_dyn_info,
3033 static struct dentry *d_tracer;
3035 struct dentry *tracing_init_dentry(void)
3042 d_tracer = debugfs_create_dir("tracing", NULL);
3044 if (!d_tracer && !once) {
3046 pr_warning("Could not create debugfs directory 'tracing'\n");
3053 #ifdef CONFIG_FTRACE_SELFTEST
3054 /* Let selftest have access to static functions in this file */
3055 #include "trace_selftest.c"
3058 static __init int tracer_init_debugfs(void)
3060 struct dentry *d_tracer;
3061 struct dentry *entry;
3063 d_tracer = tracing_init_dentry();
3065 entry = debugfs_create_file("tracing_enabled", 0644, d_tracer,
3066 &global_trace, &tracing_ctrl_fops);
3068 pr_warning("Could not create debugfs 'tracing_enabled' entry\n");
3070 entry = debugfs_create_file("iter_ctrl", 0644, d_tracer,
3071 NULL, &tracing_iter_fops);
3073 pr_warning("Could not create debugfs 'iter_ctrl' entry\n");
3075 entry = debugfs_create_file("tracing_cpumask", 0644, d_tracer,
3076 NULL, &tracing_cpumask_fops);
3078 pr_warning("Could not create debugfs 'tracing_cpumask' entry\n");
3080 entry = debugfs_create_file("latency_trace", 0444, d_tracer,
3081 &global_trace, &tracing_lt_fops);
3083 pr_warning("Could not create debugfs 'latency_trace' entry\n");
3085 entry = debugfs_create_file("trace", 0444, d_tracer,
3086 &global_trace, &tracing_fops);
3088 pr_warning("Could not create debugfs 'trace' entry\n");
3090 entry = debugfs_create_file("available_tracers", 0444, d_tracer,
3091 &global_trace, &show_traces_fops);
3093 pr_warning("Could not create debugfs 'available_tracers' entry\n");
3095 entry = debugfs_create_file("current_tracer", 0444, d_tracer,
3096 &global_trace, &set_tracer_fops);
3098 pr_warning("Could not create debugfs 'current_tracer' entry\n");
3100 entry = debugfs_create_file("tracing_max_latency", 0644, d_tracer,
3101 &tracing_max_latency,
3102 &tracing_max_lat_fops);
3104 pr_warning("Could not create debugfs "
3105 "'tracing_max_latency' entry\n");
3107 entry = debugfs_create_file("tracing_thresh", 0644, d_tracer,
3108 &tracing_thresh, &tracing_max_lat_fops);
3110 pr_warning("Could not create debugfs "
3111 "'tracing_thresh' entry\n");
3112 entry = debugfs_create_file("README", 0644, d_tracer,
3113 NULL, &tracing_readme_fops);
3115 pr_warning("Could not create debugfs 'README' entry\n");
3117 entry = debugfs_create_file("trace_pipe", 0644, d_tracer,
3118 NULL, &tracing_pipe_fops);
3120 pr_warning("Could not create debugfs "
3121 "'trace_pipe' entry\n");
3123 entry = debugfs_create_file("trace_entries", 0644, d_tracer,
3124 &global_trace, &tracing_entries_fops);
3126 pr_warning("Could not create debugfs "
3127 "'trace_entries' entry\n");
3129 entry = debugfs_create_file("trace_marker", 0220, d_tracer,
3130 NULL, &tracing_mark_fops);
3132 pr_warning("Could not create debugfs "
3133 "'trace_marker' entry\n");
3135 #ifdef CONFIG_DYNAMIC_FTRACE
3136 entry = debugfs_create_file("dyn_ftrace_total_info", 0444, d_tracer,
3137 &ftrace_update_tot_cnt,
3138 &tracing_dyn_info_fops);
3140 pr_warning("Could not create debugfs "
3141 "'dyn_ftrace_total_info' entry\n");
3143 #ifdef CONFIG_SYSPROF_TRACER
3144 init_tracer_sysprof_debugfs(d_tracer);
3149 int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
3151 static DEFINE_SPINLOCK(trace_buf_lock);
3152 static char trace_buf[TRACE_BUF_SIZE];
3154 struct ring_buffer_event *event;
3155 struct trace_array *tr = &global_trace;
3156 struct trace_array_cpu *data;
3157 struct print_entry *entry;
3158 unsigned long flags, irq_flags;
3159 int cpu, len = 0, size, pc;
3161 if (tracing_disabled)
3164 pc = preempt_count();
3165 preempt_disable_notrace();
3166 cpu = raw_smp_processor_id();
3167 data = tr->data[cpu];
3169 if (unlikely(atomic_read(&data->disabled)))
3172 spin_lock_irqsave(&trace_buf_lock, flags);
3173 len = vsnprintf(trace_buf, TRACE_BUF_SIZE, fmt, args);
3175 len = min(len, TRACE_BUF_SIZE-1);
3178 size = sizeof(*entry) + len + 1;
3179 event = ring_buffer_lock_reserve(tr->buffer, size, &irq_flags);
3182 entry = ring_buffer_event_data(event);
3183 tracing_generic_entry_update(&entry->ent, flags, pc);
3184 entry->ent.type = TRACE_PRINT;
3187 memcpy(&entry->buf, trace_buf, len);
3188 entry->buf[len] = 0;
3189 ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
3192 spin_unlock_irqrestore(&trace_buf_lock, flags);
3195 preempt_enable_notrace();
3199 EXPORT_SYMBOL_GPL(trace_vprintk);
3201 int __ftrace_printk(unsigned long ip, const char *fmt, ...)
3206 if (!(trace_flags & TRACE_ITER_PRINTK))
3210 ret = trace_vprintk(ip, fmt, ap);
3214 EXPORT_SYMBOL_GPL(__ftrace_printk);
3216 static int trace_panic_handler(struct notifier_block *this,
3217 unsigned long event, void *unused)
3219 if (ftrace_dump_on_oops)
3224 static struct notifier_block trace_panic_notifier = {
3225 .notifier_call = trace_panic_handler,
3227 .priority = 150 /* priority: INT_MAX >= x >= 0 */
3230 static int trace_die_handler(struct notifier_block *self,
3236 if (ftrace_dump_on_oops)
3245 static struct notifier_block trace_die_notifier = {
3246 .notifier_call = trace_die_handler,
3251 * printk is set to max of 1024, we really don't need it that big.
3252 * Nothing should be printing 1000 characters anyway.
3254 #define TRACE_MAX_PRINT 1000
3257 * Define here KERN_TRACE so that we have one place to modify
3258 * it if we decide to change what log level the ftrace dump
3261 #define KERN_TRACE KERN_INFO
3264 trace_printk_seq(struct trace_seq *s)
3266 /* Probably should print a warning here. */
3270 /* should be zero ended, but we are paranoid. */
3271 s->buffer[s->len] = 0;
3273 printk(KERN_TRACE "%s", s->buffer);
3278 void ftrace_dump(void)
3280 static DEFINE_SPINLOCK(ftrace_dump_lock);
3281 /* use static because iter can be a bit big for the stack */
3282 static struct trace_iterator iter;
3283 static cpumask_t mask;
3284 static int dump_ran;
3285 unsigned long flags;
3289 spin_lock_irqsave(&ftrace_dump_lock, flags);
3295 /* No turning back! */
3298 for_each_tracing_cpu(cpu) {
3299 atomic_inc(&global_trace.data[cpu]->disabled);
3302 printk(KERN_TRACE "Dumping ftrace buffer:\n");
3304 iter.tr = &global_trace;
3305 iter.trace = current_trace;
3308 * We need to stop all tracing on all CPUS to read the
3309 * the next buffer. This is a bit expensive, but is
3310 * not done often. We fill all what we can read,
3311 * and then release the locks again.
3316 while (!trace_empty(&iter)) {
3319 printk(KERN_TRACE "---------------------------------\n");
3323 /* reset all but tr, trace, and overruns */
3324 memset(&iter.seq, 0,
3325 sizeof(struct trace_iterator) -
3326 offsetof(struct trace_iterator, seq));
3327 iter.iter_flags |= TRACE_FILE_LAT_FMT;
3330 if (find_next_entry_inc(&iter) != NULL) {
3331 print_trace_line(&iter);
3332 trace_consume(&iter);
3335 trace_printk_seq(&iter.seq);
3339 printk(KERN_TRACE " (ftrace buffer empty)\n");
3341 printk(KERN_TRACE "---------------------------------\n");
3344 spin_unlock_irqrestore(&ftrace_dump_lock, flags);
3347 __init static int tracer_alloc_buffers(void)
3349 struct trace_array_cpu *data;
3352 /* TODO: make the number of buffers hot pluggable with CPUS */
3353 tracing_buffer_mask = cpu_possible_map;
3355 global_trace.buffer = ring_buffer_alloc(trace_buf_size,
3356 TRACE_BUFFER_FLAGS);
3357 if (!global_trace.buffer) {
3358 printk(KERN_ERR "tracer: failed to allocate ring buffer!\n");
3362 global_trace.entries = ring_buffer_size(global_trace.buffer);
3364 #ifdef CONFIG_TRACER_MAX_TRACE
3365 max_tr.buffer = ring_buffer_alloc(trace_buf_size,
3366 TRACE_BUFFER_FLAGS);
3367 if (!max_tr.buffer) {
3368 printk(KERN_ERR "tracer: failed to allocate max ring buffer!\n");
3370 ring_buffer_free(global_trace.buffer);
3373 max_tr.entries = ring_buffer_size(max_tr.buffer);
3374 WARN_ON(max_tr.entries != global_trace.entries);
3377 /* Allocate the first page for all buffers */
3378 for_each_tracing_cpu(i) {
3379 data = global_trace.data[i] = &per_cpu(global_trace_cpu, i);
3380 max_tr.data[i] = &per_cpu(max_data, i);
3383 trace_init_cmdlines();
3385 register_tracer(&nop_trace);
3386 #ifdef CONFIG_BOOT_TRACER
3387 register_tracer(&boot_tracer);
3388 current_trace = &boot_tracer;
3389 current_trace->init(&global_trace);
3391 current_trace = &nop_trace;
3394 /* All seems OK, enable tracing */
3395 tracing_disabled = 0;
3397 atomic_notifier_chain_register(&panic_notifier_list,
3398 &trace_panic_notifier);
3400 register_die_notifier(&trace_die_notifier);
3404 early_initcall(tracer_alloc_buffers);
3405 fs_initcall(tracer_init_debugfs);