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;
57 * If a tracer is running, we do not want to run SELFTEST.
59 static bool __read_mostly tracing_selftest_disabled;
61 /* For tracers that don't implement custom flags */
62 static struct tracer_opt dummy_tracer_opt[] = {
66 static struct tracer_flags dummy_tracer_flags = {
68 .opts = dummy_tracer_opt
71 static int dummy_set_flag(u32 old_flags, u32 bit, int set)
77 * Kill all tracing for good (never come back).
78 * It is initialized to 1 but will turn to zero if the initialization
79 * of the tracer is successful. But that is the only place that sets
82 int tracing_disabled = 1;
84 static DEFINE_PER_CPU(local_t, ftrace_cpu_disabled);
86 static inline void ftrace_disable_cpu(void)
89 local_inc(&__get_cpu_var(ftrace_cpu_disabled));
92 static inline void ftrace_enable_cpu(void)
94 local_dec(&__get_cpu_var(ftrace_cpu_disabled));
98 static cpumask_var_t __read_mostly tracing_buffer_mask;
100 #define for_each_tracing_cpu(cpu) \
101 for_each_cpu(cpu, tracing_buffer_mask)
104 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
106 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
107 * is set, then ftrace_dump is called. This will output the contents
108 * of the ftrace buffers to the console. This is very useful for
109 * capturing traces that lead to crashes and outputing it to a
112 * It is default off, but you can enable it with either specifying
113 * "ftrace_dump_on_oops" in the kernel command line, or setting
114 * /proc/sys/kernel/ftrace_dump_on_oops to true.
116 int ftrace_dump_on_oops;
118 static int tracing_set_tracer(const char *buf);
120 #define BOOTUP_TRACER_SIZE 100
121 static char bootup_tracer_buf[BOOTUP_TRACER_SIZE] __initdata;
122 static char *default_bootup_tracer;
124 static int __init set_ftrace(char *str)
126 strncpy(bootup_tracer_buf, str, BOOTUP_TRACER_SIZE);
127 default_bootup_tracer = bootup_tracer_buf;
130 __setup("ftrace=", set_ftrace);
132 static int __init set_ftrace_dump_on_oops(char *str)
134 ftrace_dump_on_oops = 1;
137 __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
140 ns2usecs(cycle_t nsec)
147 cycle_t ftrace_now(int cpu)
149 u64 ts = ring_buffer_time_stamp(cpu);
150 ring_buffer_normalize_time_stamp(cpu, &ts);
155 * The global_trace is the descriptor that holds the tracing
156 * buffers for the live tracing. For each CPU, it contains
157 * a link list of pages that will store trace entries. The
158 * page descriptor of the pages in the memory is used to hold
159 * the link list by linking the lru item in the page descriptor
160 * to each of the pages in the buffer per CPU.
162 * For each active CPU there is a data field that holds the
163 * pages for the buffer for that CPU. Each CPU has the same number
164 * of pages allocated for its buffer.
166 static struct trace_array global_trace;
168 static DEFINE_PER_CPU(struct trace_array_cpu, global_trace_cpu);
171 * The max_tr is used to snapshot the global_trace when a maximum
172 * latency is reached. Some tracers will use this to store a maximum
173 * trace while it continues examining live traces.
175 * The buffers for the max_tr are set up the same as the global_trace.
176 * When a snapshot is taken, the link list of the max_tr is swapped
177 * with the link list of the global_trace and the buffers are reset for
178 * the global_trace so the tracing can continue.
180 static struct trace_array max_tr;
182 static DEFINE_PER_CPU(struct trace_array_cpu, max_data);
184 /* tracer_enabled is used to toggle activation of a tracer */
185 static int tracer_enabled = 1;
188 * tracing_is_enabled - return tracer_enabled status
190 * This function is used by other tracers to know the status
191 * of the tracer_enabled flag. Tracers may use this function
192 * to know if it should enable their features when starting
193 * up. See irqsoff tracer for an example (start_irqsoff_tracer).
195 int tracing_is_enabled(void)
197 return tracer_enabled;
201 * trace_buf_size is the size in bytes that is allocated
202 * for a buffer. Note, the number of bytes is always rounded
205 * This number is purposely set to a low number of 16384.
206 * If the dump on oops happens, it will be much appreciated
207 * to not have to wait for all that output. Anyway this can be
208 * boot time and run time configurable.
210 #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
212 static unsigned long trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
214 /* trace_types holds a link list of available tracers. */
215 static struct tracer *trace_types __read_mostly;
217 /* current_trace points to the tracer that is currently active */
218 static struct tracer *current_trace __read_mostly;
221 * max_tracer_type_len is used to simplify the allocating of
222 * buffers to read userspace tracer names. We keep track of
223 * the longest tracer name registered.
225 static int max_tracer_type_len;
228 * trace_types_lock is used to protect the trace_types list.
229 * This lock is also used to keep user access serialized.
230 * Accesses from userspace will grab this lock while userspace
231 * activities happen inside the kernel.
233 static DEFINE_MUTEX(trace_types_lock);
235 /* trace_wait is a waitqueue for tasks blocked on trace_poll */
236 static DECLARE_WAIT_QUEUE_HEAD(trace_wait);
238 /* trace_flags holds trace_options default values */
239 unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK |
240 TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO;
243 * trace_wake_up - wake up tasks waiting for trace input
245 * Simply wakes up any task that is blocked on the trace_wait
246 * queue. These is used with trace_poll for tasks polling the trace.
248 void trace_wake_up(void)
251 * The runqueue_is_locked() can fail, but this is the best we
254 if (!(trace_flags & TRACE_ITER_BLOCK) && !runqueue_is_locked())
255 wake_up(&trace_wait);
258 static int __init set_buf_size(char *str)
260 unsigned long buf_size;
265 ret = strict_strtoul(str, 0, &buf_size);
266 /* nr_entries can not be zero */
267 if (ret < 0 || buf_size == 0)
269 trace_buf_size = buf_size;
272 __setup("trace_buf_size=", set_buf_size);
274 unsigned long nsecs_to_usecs(unsigned long nsecs)
279 /* These must match the bit postions in trace_iterator_flags */
280 static const char *trace_options[] = {
303 * ftrace_max_lock is used to protect the swapping of buffers
304 * when taking a max snapshot. The buffers themselves are
305 * protected by per_cpu spinlocks. But the action of the swap
306 * needs its own lock.
308 * This is defined as a raw_spinlock_t in order to help
309 * with performance when lockdep debugging is enabled.
311 static raw_spinlock_t ftrace_max_lock =
312 (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
315 * Copy the new maximum trace into the separate maximum-trace
316 * structure. (this way the maximum trace is permanently saved,
317 * for later retrieval via /debugfs/tracing/latency_trace)
320 __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
322 struct trace_array_cpu *data = tr->data[cpu];
325 max_tr.time_start = data->preempt_timestamp;
327 data = max_tr.data[cpu];
328 data->saved_latency = tracing_max_latency;
330 memcpy(data->comm, tsk->comm, TASK_COMM_LEN);
331 data->pid = tsk->pid;
332 data->uid = task_uid(tsk);
333 data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
334 data->policy = tsk->policy;
335 data->rt_priority = tsk->rt_priority;
337 /* record this tasks comm */
338 tracing_record_cmdline(current);
342 trace_seq_reset(struct trace_seq *s)
348 ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
353 if (s->len <= s->readpos)
356 len = s->len - s->readpos;
359 ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
368 trace_print_seq(struct seq_file *m, struct trace_seq *s)
370 int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len;
373 seq_puts(m, s->buffer);
379 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
381 * @tsk: the task with the latency
382 * @cpu: The cpu that initiated the trace.
384 * Flip the buffers between the @tr and the max_tr and record information
385 * about which task was the cause of this latency.
388 update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
390 struct ring_buffer *buf = tr->buffer;
392 WARN_ON_ONCE(!irqs_disabled());
393 __raw_spin_lock(&ftrace_max_lock);
395 tr->buffer = max_tr.buffer;
398 ftrace_disable_cpu();
399 ring_buffer_reset(tr->buffer);
402 __update_max_tr(tr, tsk, cpu);
403 __raw_spin_unlock(&ftrace_max_lock);
407 * update_max_tr_single - only copy one trace over, and reset the rest
409 * @tsk - task with the latency
410 * @cpu - the cpu of the buffer to copy.
412 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
415 update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
419 WARN_ON_ONCE(!irqs_disabled());
420 __raw_spin_lock(&ftrace_max_lock);
422 ftrace_disable_cpu();
424 ring_buffer_reset(max_tr.buffer);
425 ret = ring_buffer_swap_cpu(max_tr.buffer, tr->buffer, cpu);
429 WARN_ON_ONCE(ret && ret != -EAGAIN);
431 __update_max_tr(tr, tsk, cpu);
432 __raw_spin_unlock(&ftrace_max_lock);
436 * register_tracer - register a tracer with the ftrace system.
437 * @type - the plugin for the tracer
439 * Register a new plugin tracer.
441 int register_tracer(struct tracer *type)
448 pr_info("Tracer must have a name\n");
453 * When this gets called we hold the BKL which means that
454 * preemption is disabled. Various trace selftests however
455 * need to disable and enable preemption for successful tests.
456 * So we drop the BKL here and grab it after the tests again.
459 mutex_lock(&trace_types_lock);
461 tracing_selftest_running = true;
463 for (t = trace_types; t; t = t->next) {
464 if (strcmp(type->name, t->name) == 0) {
466 pr_info("Trace %s already registered\n",
474 type->set_flag = &dummy_set_flag;
476 type->flags = &dummy_tracer_flags;
478 if (!type->flags->opts)
479 type->flags->opts = dummy_tracer_opt;
481 #ifdef CONFIG_FTRACE_STARTUP_TEST
482 if (type->selftest && !tracing_selftest_disabled) {
483 struct tracer *saved_tracer = current_trace;
484 struct trace_array *tr = &global_trace;
488 * Run a selftest on this tracer.
489 * Here we reset the trace buffer, and set the current
490 * tracer to be this tracer. The tracer can then run some
491 * internal tracing to verify that everything is in order.
492 * If we fail, we do not register this tracer.
494 for_each_tracing_cpu(i)
495 tracing_reset(tr, i);
497 current_trace = type;
498 /* the test is responsible for initializing and enabling */
499 pr_info("Testing tracer %s: ", type->name);
500 ret = type->selftest(type, tr);
501 /* the test is responsible for resetting too */
502 current_trace = saved_tracer;
504 printk(KERN_CONT "FAILED!\n");
507 /* Only reset on passing, to avoid touching corrupted buffers */
508 for_each_tracing_cpu(i)
509 tracing_reset(tr, i);
511 printk(KERN_CONT "PASSED\n");
515 type->next = trace_types;
517 len = strlen(type->name);
518 if (len > max_tracer_type_len)
519 max_tracer_type_len = len;
522 tracing_selftest_running = false;
523 mutex_unlock(&trace_types_lock);
525 if (ret || !default_bootup_tracer)
528 if (strncmp(default_bootup_tracer, type->name, BOOTUP_TRACER_SIZE))
531 printk(KERN_INFO "Starting tracer '%s'\n", type->name);
532 /* Do we want this tracer to start on bootup? */
533 tracing_set_tracer(type->name);
534 default_bootup_tracer = NULL;
535 /* disable other selftests, since this will break it. */
536 tracing_selftest_disabled = 1;
537 #ifdef CONFIG_FTRACE_STARTUP_TEST
538 printk(KERN_INFO "Disabling FTRACE selftests due to running tracer '%s'\n",
547 void unregister_tracer(struct tracer *type)
552 mutex_lock(&trace_types_lock);
553 for (t = &trace_types; *t; t = &(*t)->next) {
557 pr_info("Trace %s not registered\n", type->name);
562 if (strlen(type->name) != max_tracer_type_len)
565 max_tracer_type_len = 0;
566 for (t = &trace_types; *t; t = &(*t)->next) {
567 len = strlen((*t)->name);
568 if (len > max_tracer_type_len)
569 max_tracer_type_len = len;
572 mutex_unlock(&trace_types_lock);
575 void tracing_reset(struct trace_array *tr, int cpu)
577 ftrace_disable_cpu();
578 ring_buffer_reset_cpu(tr->buffer, cpu);
582 void tracing_reset_online_cpus(struct trace_array *tr)
586 tr->time_start = ftrace_now(tr->cpu);
588 for_each_online_cpu(cpu)
589 tracing_reset(tr, cpu);
592 #define SAVED_CMDLINES 128
593 static unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
594 static unsigned map_cmdline_to_pid[SAVED_CMDLINES];
595 static char saved_cmdlines[SAVED_CMDLINES][TASK_COMM_LEN];
596 static int cmdline_idx;
597 static DEFINE_SPINLOCK(trace_cmdline_lock);
599 /* temporary disable recording */
600 atomic_t trace_record_cmdline_disabled __read_mostly;
602 static void trace_init_cmdlines(void)
604 memset(&map_pid_to_cmdline, -1, sizeof(map_pid_to_cmdline));
605 memset(&map_cmdline_to_pid, -1, sizeof(map_cmdline_to_pid));
609 static int trace_stop_count;
610 static DEFINE_SPINLOCK(tracing_start_lock);
613 * ftrace_off_permanent - disable all ftrace code permanently
615 * This should only be called when a serious anomally has
616 * been detected. This will turn off the function tracing,
617 * ring buffers, and other tracing utilites. It takes no
618 * locks and can be called from any context.
620 void ftrace_off_permanent(void)
622 tracing_disabled = 1;
624 tracing_off_permanent();
628 * tracing_start - quick start of the tracer
630 * If tracing is enabled but was stopped by tracing_stop,
631 * this will start the tracer back up.
633 void tracing_start(void)
635 struct ring_buffer *buffer;
638 if (tracing_disabled)
641 spin_lock_irqsave(&tracing_start_lock, flags);
642 if (--trace_stop_count) {
643 if (trace_stop_count < 0) {
644 /* Someone screwed up their debugging */
646 trace_stop_count = 0;
652 buffer = global_trace.buffer;
654 ring_buffer_record_enable(buffer);
656 buffer = max_tr.buffer;
658 ring_buffer_record_enable(buffer);
662 spin_unlock_irqrestore(&tracing_start_lock, flags);
666 * tracing_stop - quick stop of the tracer
668 * Light weight way to stop tracing. Use in conjunction with
671 void tracing_stop(void)
673 struct ring_buffer *buffer;
677 spin_lock_irqsave(&tracing_start_lock, flags);
678 if (trace_stop_count++)
681 buffer = global_trace.buffer;
683 ring_buffer_record_disable(buffer);
685 buffer = max_tr.buffer;
687 ring_buffer_record_disable(buffer);
690 spin_unlock_irqrestore(&tracing_start_lock, flags);
693 void trace_stop_cmdline_recording(void);
695 static void trace_save_cmdline(struct task_struct *tsk)
700 if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT))
704 * It's not the end of the world if we don't get
705 * the lock, but we also don't want to spin
706 * nor do we want to disable interrupts,
707 * so if we miss here, then better luck next time.
709 if (!spin_trylock(&trace_cmdline_lock))
712 idx = map_pid_to_cmdline[tsk->pid];
713 if (idx >= SAVED_CMDLINES) {
714 idx = (cmdline_idx + 1) % SAVED_CMDLINES;
716 map = map_cmdline_to_pid[idx];
717 if (map <= PID_MAX_DEFAULT)
718 map_pid_to_cmdline[map] = (unsigned)-1;
720 map_pid_to_cmdline[tsk->pid] = idx;
725 memcpy(&saved_cmdlines[idx], tsk->comm, TASK_COMM_LEN);
727 spin_unlock(&trace_cmdline_lock);
730 char *trace_find_cmdline(int pid)
732 char *cmdline = "<...>";
738 if (pid > PID_MAX_DEFAULT)
741 map = map_pid_to_cmdline[pid];
742 if (map >= SAVED_CMDLINES)
745 cmdline = saved_cmdlines[map];
751 void tracing_record_cmdline(struct task_struct *tsk)
753 if (atomic_read(&trace_record_cmdline_disabled))
756 trace_save_cmdline(tsk);
760 tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
763 struct task_struct *tsk = current;
765 entry->preempt_count = pc & 0xff;
766 entry->pid = (tsk) ? tsk->pid : 0;
767 entry->tgid = (tsk) ? tsk->tgid : 0;
769 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
770 (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
772 TRACE_FLAG_IRQS_NOSUPPORT |
774 ((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
775 ((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
776 (need_resched() ? TRACE_FLAG_NEED_RESCHED : 0);
779 struct ring_buffer_event *trace_buffer_lock_reserve(struct trace_array *tr,
782 unsigned long flags, int pc)
784 struct ring_buffer_event *event;
786 event = ring_buffer_lock_reserve(tr->buffer, len);
788 struct trace_entry *ent = ring_buffer_event_data(event);
790 tracing_generic_entry_update(ent, flags, pc);
796 static void ftrace_trace_stack(struct trace_array *tr,
797 unsigned long flags, int skip, int pc);
798 static void ftrace_trace_userstack(struct trace_array *tr,
799 unsigned long flags, int pc);
801 void trace_buffer_unlock_commit(struct trace_array *tr,
802 struct ring_buffer_event *event,
803 unsigned long flags, int pc)
805 ring_buffer_unlock_commit(tr->buffer, event);
807 ftrace_trace_stack(tr, flags, 6, pc);
808 ftrace_trace_userstack(tr, flags, pc);
813 trace_function(struct trace_array *tr,
814 unsigned long ip, unsigned long parent_ip, unsigned long flags,
817 struct ring_buffer_event *event;
818 struct ftrace_entry *entry;
820 /* If we are reading the ring buffer, don't trace */
821 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
824 event = trace_buffer_lock_reserve(tr, TRACE_FN, sizeof(*entry),
828 entry = ring_buffer_event_data(event);
830 entry->parent_ip = parent_ip;
831 ring_buffer_unlock_commit(tr->buffer, event);
834 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
835 static void __trace_graph_entry(struct trace_array *tr,
836 struct ftrace_graph_ent *trace,
840 struct ring_buffer_event *event;
841 struct ftrace_graph_ent_entry *entry;
843 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
846 event = trace_buffer_lock_reserve(&global_trace, TRACE_GRAPH_ENT,
847 sizeof(*entry), flags, pc);
850 entry = ring_buffer_event_data(event);
851 entry->graph_ent = *trace;
852 ring_buffer_unlock_commit(global_trace.buffer, event);
855 static void __trace_graph_return(struct trace_array *tr,
856 struct ftrace_graph_ret *trace,
860 struct ring_buffer_event *event;
861 struct ftrace_graph_ret_entry *entry;
863 if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
866 event = trace_buffer_lock_reserve(&global_trace, TRACE_GRAPH_RET,
867 sizeof(*entry), flags, pc);
870 entry = ring_buffer_event_data(event);
872 ring_buffer_unlock_commit(global_trace.buffer, event);
877 ftrace(struct trace_array *tr, struct trace_array_cpu *data,
878 unsigned long ip, unsigned long parent_ip, unsigned long flags,
881 if (likely(!atomic_read(&data->disabled)))
882 trace_function(tr, ip, parent_ip, flags, pc);
885 static void __ftrace_trace_stack(struct trace_array *tr,
889 #ifdef CONFIG_STACKTRACE
890 struct ring_buffer_event *event;
891 struct stack_entry *entry;
892 struct stack_trace trace;
894 event = trace_buffer_lock_reserve(tr, TRACE_STACK,
895 sizeof(*entry), flags, pc);
898 entry = ring_buffer_event_data(event);
899 memset(&entry->caller, 0, sizeof(entry->caller));
901 trace.nr_entries = 0;
902 trace.max_entries = FTRACE_STACK_ENTRIES;
904 trace.entries = entry->caller;
906 save_stack_trace(&trace);
907 ring_buffer_unlock_commit(tr->buffer, event);
911 static void ftrace_trace_stack(struct trace_array *tr,
915 if (!(trace_flags & TRACE_ITER_STACKTRACE))
918 __ftrace_trace_stack(tr, flags, skip, pc);
921 void __trace_stack(struct trace_array *tr,
925 __ftrace_trace_stack(tr, flags, skip, pc);
928 static void ftrace_trace_userstack(struct trace_array *tr,
929 unsigned long flags, int pc)
931 #ifdef CONFIG_STACKTRACE
932 struct ring_buffer_event *event;
933 struct userstack_entry *entry;
934 struct stack_trace trace;
936 if (!(trace_flags & TRACE_ITER_USERSTACKTRACE))
939 event = trace_buffer_lock_reserve(tr, TRACE_USER_STACK,
940 sizeof(*entry), flags, pc);
943 entry = ring_buffer_event_data(event);
945 memset(&entry->caller, 0, sizeof(entry->caller));
947 trace.nr_entries = 0;
948 trace.max_entries = FTRACE_STACK_ENTRIES;
950 trace.entries = entry->caller;
952 save_stack_trace_user(&trace);
953 ring_buffer_unlock_commit(tr->buffer, event);
957 void __trace_userstack(struct trace_array *tr, unsigned long flags)
959 ftrace_trace_userstack(tr, flags, preempt_count());
963 ftrace_trace_special(void *__tr,
964 unsigned long arg1, unsigned long arg2, unsigned long arg3,
967 struct ring_buffer_event *event;
968 struct trace_array *tr = __tr;
969 struct special_entry *entry;
971 event = trace_buffer_lock_reserve(tr, TRACE_SPECIAL,
972 sizeof(*entry), 0, pc);
975 entry = ring_buffer_event_data(event);
979 trace_buffer_unlock_commit(tr, event, 0, pc);
983 __trace_special(void *__tr, void *__data,
984 unsigned long arg1, unsigned long arg2, unsigned long arg3)
986 ftrace_trace_special(__tr, arg1, arg2, arg3, preempt_count());
990 tracing_sched_switch_trace(struct trace_array *tr,
991 struct task_struct *prev,
992 struct task_struct *next,
993 unsigned long flags, int pc)
995 struct ring_buffer_event *event;
996 struct ctx_switch_entry *entry;
998 event = trace_buffer_lock_reserve(tr, TRACE_CTX,
999 sizeof(*entry), flags, pc);
1002 entry = ring_buffer_event_data(event);
1003 entry->prev_pid = prev->pid;
1004 entry->prev_prio = prev->prio;
1005 entry->prev_state = prev->state;
1006 entry->next_pid = next->pid;
1007 entry->next_prio = next->prio;
1008 entry->next_state = next->state;
1009 entry->next_cpu = task_cpu(next);
1010 trace_buffer_unlock_commit(tr, event, flags, pc);
1014 tracing_sched_wakeup_trace(struct trace_array *tr,
1015 struct task_struct *wakee,
1016 struct task_struct *curr,
1017 unsigned long flags, int pc)
1019 struct ring_buffer_event *event;
1020 struct ctx_switch_entry *entry;
1022 event = trace_buffer_lock_reserve(tr, TRACE_WAKE,
1023 sizeof(*entry), flags, pc);
1026 entry = ring_buffer_event_data(event);
1027 entry->prev_pid = curr->pid;
1028 entry->prev_prio = curr->prio;
1029 entry->prev_state = curr->state;
1030 entry->next_pid = wakee->pid;
1031 entry->next_prio = wakee->prio;
1032 entry->next_state = wakee->state;
1033 entry->next_cpu = task_cpu(wakee);
1034 trace_buffer_unlock_commit(tr, event, flags, pc);
1038 ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3)
1040 struct trace_array *tr = &global_trace;
1041 struct trace_array_cpu *data;
1042 unsigned long flags;
1046 if (tracing_disabled)
1049 pc = preempt_count();
1050 local_irq_save(flags);
1051 cpu = raw_smp_processor_id();
1052 data = tr->data[cpu];
1054 if (likely(atomic_inc_return(&data->disabled) == 1))
1055 ftrace_trace_special(tr, arg1, arg2, arg3, pc);
1057 atomic_dec(&data->disabled);
1058 local_irq_restore(flags);
1061 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1062 int trace_graph_entry(struct ftrace_graph_ent *trace)
1064 struct trace_array *tr = &global_trace;
1065 struct trace_array_cpu *data;
1066 unsigned long flags;
1071 if (!ftrace_trace_task(current))
1074 if (!ftrace_graph_addr(trace->func))
1077 local_irq_save(flags);
1078 cpu = raw_smp_processor_id();
1079 data = tr->data[cpu];
1080 disabled = atomic_inc_return(&data->disabled);
1081 if (likely(disabled == 1)) {
1082 pc = preempt_count();
1083 __trace_graph_entry(tr, trace, flags, pc);
1085 /* Only do the atomic if it is not already set */
1086 if (!test_tsk_trace_graph(current))
1087 set_tsk_trace_graph(current);
1088 atomic_dec(&data->disabled);
1089 local_irq_restore(flags);
1094 void trace_graph_return(struct ftrace_graph_ret *trace)
1096 struct trace_array *tr = &global_trace;
1097 struct trace_array_cpu *data;
1098 unsigned long flags;
1103 local_irq_save(flags);
1104 cpu = raw_smp_processor_id();
1105 data = tr->data[cpu];
1106 disabled = atomic_inc_return(&data->disabled);
1107 if (likely(disabled == 1)) {
1108 pc = preempt_count();
1109 __trace_graph_return(tr, trace, flags, pc);
1112 clear_tsk_trace_graph(current);
1113 atomic_dec(&data->disabled);
1114 local_irq_restore(flags);
1116 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
1118 enum trace_file_type {
1119 TRACE_FILE_LAT_FMT = 1,
1120 TRACE_FILE_ANNOTATE = 2,
1123 static void trace_iterator_increment(struct trace_iterator *iter)
1125 /* Don't allow ftrace to trace into the ring buffers */
1126 ftrace_disable_cpu();
1129 if (iter->buffer_iter[iter->cpu])
1130 ring_buffer_read(iter->buffer_iter[iter->cpu], NULL);
1132 ftrace_enable_cpu();
1135 static struct trace_entry *
1136 peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts)
1138 struct ring_buffer_event *event;
1139 struct ring_buffer_iter *buf_iter = iter->buffer_iter[cpu];
1141 /* Don't allow ftrace to trace into the ring buffers */
1142 ftrace_disable_cpu();
1145 event = ring_buffer_iter_peek(buf_iter, ts);
1147 event = ring_buffer_peek(iter->tr->buffer, cpu, ts);
1149 ftrace_enable_cpu();
1151 return event ? ring_buffer_event_data(event) : NULL;
1154 static struct trace_entry *
1155 __find_next_entry(struct trace_iterator *iter, int *ent_cpu, u64 *ent_ts)
1157 struct ring_buffer *buffer = iter->tr->buffer;
1158 struct trace_entry *ent, *next = NULL;
1159 u64 next_ts = 0, ts;
1163 for_each_tracing_cpu(cpu) {
1165 if (ring_buffer_empty_cpu(buffer, cpu))
1168 ent = peek_next_entry(iter, cpu, &ts);
1171 * Pick the entry with the smallest timestamp:
1173 if (ent && (!next || ts < next_ts)) {
1181 *ent_cpu = next_cpu;
1189 /* Find the next real entry, without updating the iterator itself */
1190 struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
1191 int *ent_cpu, u64 *ent_ts)
1193 return __find_next_entry(iter, ent_cpu, ent_ts);
1196 /* Find the next real entry, and increment the iterator to the next entry */
1197 static void *find_next_entry_inc(struct trace_iterator *iter)
1199 iter->ent = __find_next_entry(iter, &iter->cpu, &iter->ts);
1202 trace_iterator_increment(iter);
1204 return iter->ent ? iter : NULL;
1207 static void trace_consume(struct trace_iterator *iter)
1209 /* Don't allow ftrace to trace into the ring buffers */
1210 ftrace_disable_cpu();
1211 ring_buffer_consume(iter->tr->buffer, iter->cpu, &iter->ts);
1212 ftrace_enable_cpu();
1215 static void *s_next(struct seq_file *m, void *v, loff_t *pos)
1217 struct trace_iterator *iter = m->private;
1223 /* can't go backwards */
1228 ent = find_next_entry_inc(iter);
1232 while (ent && iter->idx < i)
1233 ent = find_next_entry_inc(iter);
1240 static void *s_start(struct seq_file *m, loff_t *pos)
1242 struct trace_iterator *iter = m->private;
1247 mutex_lock(&trace_types_lock);
1249 if (!current_trace || current_trace != iter->trace) {
1250 mutex_unlock(&trace_types_lock);
1254 atomic_inc(&trace_record_cmdline_disabled);
1256 if (*pos != iter->pos) {
1261 ftrace_disable_cpu();
1263 for_each_tracing_cpu(cpu) {
1264 ring_buffer_iter_reset(iter->buffer_iter[cpu]);
1267 ftrace_enable_cpu();
1269 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
1274 p = s_next(m, p, &l);
1280 static void s_stop(struct seq_file *m, void *p)
1282 atomic_dec(&trace_record_cmdline_disabled);
1283 mutex_unlock(&trace_types_lock);
1286 static void print_lat_help_header(struct seq_file *m)
1288 seq_puts(m, "# _------=> CPU# \n");
1289 seq_puts(m, "# / _-----=> irqs-off \n");
1290 seq_puts(m, "# | / _----=> need-resched \n");
1291 seq_puts(m, "# || / _---=> hardirq/softirq \n");
1292 seq_puts(m, "# ||| / _--=> preempt-depth \n");
1293 seq_puts(m, "# |||| / \n");
1294 seq_puts(m, "# ||||| delay \n");
1295 seq_puts(m, "# cmd pid ||||| time | caller \n");
1296 seq_puts(m, "# \\ / ||||| \\ | / \n");
1299 static void print_func_help_header(struct seq_file *m)
1301 seq_puts(m, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
1302 seq_puts(m, "# | | | | |\n");
1307 print_trace_header(struct seq_file *m, struct trace_iterator *iter)
1309 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1310 struct trace_array *tr = iter->tr;
1311 struct trace_array_cpu *data = tr->data[tr->cpu];
1312 struct tracer *type = current_trace;
1313 unsigned long total;
1314 unsigned long entries;
1315 const char *name = "preemption";
1320 entries = ring_buffer_entries(iter->tr->buffer);
1322 ring_buffer_overruns(iter->tr->buffer);
1324 seq_printf(m, "%s latency trace v1.1.5 on %s\n",
1326 seq_puts(m, "-----------------------------------"
1327 "---------------------------------\n");
1328 seq_printf(m, " latency: %lu us, #%lu/%lu, CPU#%d |"
1329 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
1330 nsecs_to_usecs(data->saved_latency),
1334 #if defined(CONFIG_PREEMPT_NONE)
1336 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
1338 #elif defined(CONFIG_PREEMPT)
1343 /* These are reserved for later use */
1346 seq_printf(m, " #P:%d)\n", num_online_cpus());
1350 seq_puts(m, " -----------------\n");
1351 seq_printf(m, " | task: %.16s-%d "
1352 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
1353 data->comm, data->pid, data->uid, data->nice,
1354 data->policy, data->rt_priority);
1355 seq_puts(m, " -----------------\n");
1357 if (data->critical_start) {
1358 seq_puts(m, " => started at: ");
1359 seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
1360 trace_print_seq(m, &iter->seq);
1361 seq_puts(m, "\n => ended at: ");
1362 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
1363 trace_print_seq(m, &iter->seq);
1370 static void test_cpu_buff_start(struct trace_iterator *iter)
1372 struct trace_seq *s = &iter->seq;
1374 if (!(trace_flags & TRACE_ITER_ANNOTATE))
1377 if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
1380 if (cpumask_test_cpu(iter->cpu, iter->started))
1383 cpumask_set_cpu(iter->cpu, iter->started);
1384 trace_seq_printf(s, "##### CPU %u buffer started ####\n", iter->cpu);
1387 static enum print_line_t print_lat_fmt(struct trace_iterator *iter)
1389 struct trace_seq *s = &iter->seq;
1390 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1391 struct trace_event *event;
1392 struct trace_entry *entry = iter->ent;
1394 test_cpu_buff_start(iter);
1396 event = ftrace_find_event(entry->type);
1398 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1399 if (!trace_print_lat_context(iter))
1404 return event->latency_trace(iter, sym_flags);
1406 if (!trace_seq_printf(s, "Unknown type %d\n", entry->type))
1409 return TRACE_TYPE_HANDLED;
1411 return TRACE_TYPE_PARTIAL_LINE;
1414 static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
1416 struct trace_seq *s = &iter->seq;
1417 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1418 struct trace_entry *entry;
1419 struct trace_event *event;
1423 test_cpu_buff_start(iter);
1425 event = ftrace_find_event(entry->type);
1427 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1428 if (!trace_print_context(iter))
1433 return event->trace(iter, sym_flags);
1435 if (!trace_seq_printf(s, "Unknown type %d\n", entry->type))
1438 return TRACE_TYPE_HANDLED;
1440 return TRACE_TYPE_PARTIAL_LINE;
1443 static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
1445 struct trace_seq *s = &iter->seq;
1446 struct trace_entry *entry;
1447 struct trace_event *event;
1451 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1452 if (!trace_seq_printf(s, "%d %d %llu ",
1453 entry->pid, iter->cpu, iter->ts))
1457 event = ftrace_find_event(entry->type);
1459 return event->raw(iter, 0);
1461 if (!trace_seq_printf(s, "%d ?\n", entry->type))
1464 return TRACE_TYPE_HANDLED;
1466 return TRACE_TYPE_PARTIAL_LINE;
1469 static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
1471 struct trace_seq *s = &iter->seq;
1472 unsigned char newline = '\n';
1473 struct trace_entry *entry;
1474 struct trace_event *event;
1478 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1479 SEQ_PUT_HEX_FIELD_RET(s, entry->pid);
1480 SEQ_PUT_HEX_FIELD_RET(s, iter->cpu);
1481 SEQ_PUT_HEX_FIELD_RET(s, iter->ts);
1484 event = ftrace_find_event(entry->type);
1486 enum print_line_t ret = event->hex(iter, 0);
1487 if (ret != TRACE_TYPE_HANDLED)
1491 SEQ_PUT_FIELD_RET(s, newline);
1493 return TRACE_TYPE_HANDLED;
1496 static enum print_line_t print_printk_msg_only(struct trace_iterator *iter)
1498 struct trace_seq *s = &iter->seq;
1499 struct trace_entry *entry = iter->ent;
1500 struct print_entry *field;
1503 trace_assign_type(field, entry);
1505 ret = trace_seq_printf(s, "%s", field->buf);
1507 return TRACE_TYPE_PARTIAL_LINE;
1509 return TRACE_TYPE_HANDLED;
1512 static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
1514 struct trace_seq *s = &iter->seq;
1515 struct trace_entry *entry;
1516 struct trace_event *event;
1520 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1521 SEQ_PUT_FIELD_RET(s, entry->pid);
1522 SEQ_PUT_FIELD_RET(s, entry->cpu);
1523 SEQ_PUT_FIELD_RET(s, iter->ts);
1526 event = ftrace_find_event(entry->type);
1527 return event ? event->binary(iter, 0) : TRACE_TYPE_HANDLED;
1530 static int trace_empty(struct trace_iterator *iter)
1534 for_each_tracing_cpu(cpu) {
1535 if (iter->buffer_iter[cpu]) {
1536 if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
1539 if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu))
1547 static enum print_line_t print_trace_line(struct trace_iterator *iter)
1549 enum print_line_t ret;
1551 if (iter->trace && iter->trace->print_line) {
1552 ret = iter->trace->print_line(iter);
1553 if (ret != TRACE_TYPE_UNHANDLED)
1557 if (iter->ent->type == TRACE_PRINT &&
1558 trace_flags & TRACE_ITER_PRINTK &&
1559 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
1560 return print_printk_msg_only(iter);
1562 if (trace_flags & TRACE_ITER_BIN)
1563 return print_bin_fmt(iter);
1565 if (trace_flags & TRACE_ITER_HEX)
1566 return print_hex_fmt(iter);
1568 if (trace_flags & TRACE_ITER_RAW)
1569 return print_raw_fmt(iter);
1571 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
1572 return print_lat_fmt(iter);
1574 return print_trace_fmt(iter);
1577 static int s_show(struct seq_file *m, void *v)
1579 struct trace_iterator *iter = v;
1581 if (iter->ent == NULL) {
1583 seq_printf(m, "# tracer: %s\n", iter->trace->name);
1586 if (iter->trace && iter->trace->print_header)
1587 iter->trace->print_header(m);
1588 else if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
1589 /* print nothing if the buffers are empty */
1590 if (trace_empty(iter))
1592 print_trace_header(m, iter);
1593 if (!(trace_flags & TRACE_ITER_VERBOSE))
1594 print_lat_help_header(m);
1596 if (!(trace_flags & TRACE_ITER_VERBOSE))
1597 print_func_help_header(m);
1600 print_trace_line(iter);
1601 trace_print_seq(m, &iter->seq);
1607 static struct seq_operations tracer_seq_ops = {
1614 static struct trace_iterator *
1615 __tracing_open(struct inode *inode, struct file *file, int *ret)
1617 struct trace_iterator *iter;
1621 if (tracing_disabled) {
1626 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1632 mutex_lock(&trace_types_lock);
1633 if (current_trace && current_trace->print_max)
1636 iter->tr = inode->i_private;
1637 iter->trace = current_trace;
1640 /* Notify the tracer early; before we stop tracing. */
1641 if (iter->trace && iter->trace->open)
1642 iter->trace->open(iter);
1644 /* Annotate start of buffers if we had overruns */
1645 if (ring_buffer_overruns(iter->tr->buffer))
1646 iter->iter_flags |= TRACE_FILE_ANNOTATE;
1649 for_each_tracing_cpu(cpu) {
1651 iter->buffer_iter[cpu] =
1652 ring_buffer_read_start(iter->tr->buffer, cpu);
1654 if (!iter->buffer_iter[cpu])
1658 /* TODO stop tracer */
1659 *ret = seq_open(file, &tracer_seq_ops);
1663 m = file->private_data;
1666 /* stop the trace while dumping */
1669 mutex_unlock(&trace_types_lock);
1675 for_each_tracing_cpu(cpu) {
1676 if (iter->buffer_iter[cpu])
1677 ring_buffer_read_finish(iter->buffer_iter[cpu]);
1679 mutex_unlock(&trace_types_lock);
1682 return ERR_PTR(-ENOMEM);
1685 int tracing_open_generic(struct inode *inode, struct file *filp)
1687 if (tracing_disabled)
1690 filp->private_data = inode->i_private;
1694 int tracing_release(struct inode *inode, struct file *file)
1696 struct seq_file *m = (struct seq_file *)file->private_data;
1697 struct trace_iterator *iter = m->private;
1700 mutex_lock(&trace_types_lock);
1701 for_each_tracing_cpu(cpu) {
1702 if (iter->buffer_iter[cpu])
1703 ring_buffer_read_finish(iter->buffer_iter[cpu]);
1706 if (iter->trace && iter->trace->close)
1707 iter->trace->close(iter);
1709 /* reenable tracing if it was previously enabled */
1711 mutex_unlock(&trace_types_lock);
1713 seq_release(inode, file);
1718 static int tracing_open(struct inode *inode, struct file *file)
1722 __tracing_open(inode, file, &ret);
1727 static int tracing_lt_open(struct inode *inode, struct file *file)
1729 struct trace_iterator *iter;
1732 iter = __tracing_open(inode, file, &ret);
1735 iter->iter_flags |= TRACE_FILE_LAT_FMT;
1742 t_next(struct seq_file *m, void *v, loff_t *pos)
1744 struct tracer *t = m->private;
1756 static void *t_start(struct seq_file *m, loff_t *pos)
1758 struct tracer *t = m->private;
1761 mutex_lock(&trace_types_lock);
1762 for (; t && l < *pos; t = t_next(m, t, &l))
1768 static void t_stop(struct seq_file *m, void *p)
1770 mutex_unlock(&trace_types_lock);
1773 static int t_show(struct seq_file *m, void *v)
1775 struct tracer *t = v;
1780 seq_printf(m, "%s", t->name);
1789 static struct seq_operations show_traces_seq_ops = {
1796 static int show_traces_open(struct inode *inode, struct file *file)
1800 if (tracing_disabled)
1803 ret = seq_open(file, &show_traces_seq_ops);
1805 struct seq_file *m = file->private_data;
1806 m->private = trace_types;
1812 static struct file_operations tracing_fops = {
1813 .open = tracing_open,
1815 .llseek = seq_lseek,
1816 .release = tracing_release,
1819 static struct file_operations tracing_lt_fops = {
1820 .open = tracing_lt_open,
1822 .llseek = seq_lseek,
1823 .release = tracing_release,
1826 static struct file_operations show_traces_fops = {
1827 .open = show_traces_open,
1829 .release = seq_release,
1833 * Only trace on a CPU if the bitmask is set:
1835 static cpumask_var_t tracing_cpumask;
1838 * The tracer itself will not take this lock, but still we want
1839 * to provide a consistent cpumask to user-space:
1841 static DEFINE_MUTEX(tracing_cpumask_update_lock);
1844 * Temporary storage for the character representation of the
1845 * CPU bitmask (and one more byte for the newline):
1847 static char mask_str[NR_CPUS + 1];
1850 tracing_cpumask_read(struct file *filp, char __user *ubuf,
1851 size_t count, loff_t *ppos)
1855 mutex_lock(&tracing_cpumask_update_lock);
1857 len = cpumask_scnprintf(mask_str, count, tracing_cpumask);
1858 if (count - len < 2) {
1862 len += sprintf(mask_str + len, "\n");
1863 count = simple_read_from_buffer(ubuf, count, ppos, mask_str, NR_CPUS+1);
1866 mutex_unlock(&tracing_cpumask_update_lock);
1872 tracing_cpumask_write(struct file *filp, const char __user *ubuf,
1873 size_t count, loff_t *ppos)
1876 cpumask_var_t tracing_cpumask_new;
1878 if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
1881 mutex_lock(&tracing_cpumask_update_lock);
1882 err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
1886 local_irq_disable();
1887 __raw_spin_lock(&ftrace_max_lock);
1888 for_each_tracing_cpu(cpu) {
1890 * Increase/decrease the disabled counter if we are
1891 * about to flip a bit in the cpumask:
1893 if (cpumask_test_cpu(cpu, tracing_cpumask) &&
1894 !cpumask_test_cpu(cpu, tracing_cpumask_new)) {
1895 atomic_inc(&global_trace.data[cpu]->disabled);
1897 if (!cpumask_test_cpu(cpu, tracing_cpumask) &&
1898 cpumask_test_cpu(cpu, tracing_cpumask_new)) {
1899 atomic_dec(&global_trace.data[cpu]->disabled);
1902 __raw_spin_unlock(&ftrace_max_lock);
1905 cpumask_copy(tracing_cpumask, tracing_cpumask_new);
1907 mutex_unlock(&tracing_cpumask_update_lock);
1908 free_cpumask_var(tracing_cpumask_new);
1913 mutex_unlock(&tracing_cpumask_update_lock);
1914 free_cpumask_var(tracing_cpumask);
1919 static struct file_operations tracing_cpumask_fops = {
1920 .open = tracing_open_generic,
1921 .read = tracing_cpumask_read,
1922 .write = tracing_cpumask_write,
1926 tracing_trace_options_read(struct file *filp, char __user *ubuf,
1927 size_t cnt, loff_t *ppos)
1933 u32 tracer_flags = current_trace->flags->val;
1934 struct tracer_opt *trace_opts = current_trace->flags->opts;
1937 /* calulate max size */
1938 for (i = 0; trace_options[i]; i++) {
1939 len += strlen(trace_options[i]);
1940 len += 3; /* "no" and space */
1944 * Increase the size with names of options specific
1945 * of the current tracer.
1947 for (i = 0; trace_opts[i].name; i++) {
1948 len += strlen(trace_opts[i].name);
1949 len += 3; /* "no" and space */
1952 /* +2 for \n and \0 */
1953 buf = kmalloc(len + 2, GFP_KERNEL);
1957 for (i = 0; trace_options[i]; i++) {
1958 if (trace_flags & (1 << i))
1959 r += sprintf(buf + r, "%s ", trace_options[i]);
1961 r += sprintf(buf + r, "no%s ", trace_options[i]);
1964 for (i = 0; trace_opts[i].name; i++) {
1965 if (tracer_flags & trace_opts[i].bit)
1966 r += sprintf(buf + r, "%s ",
1967 trace_opts[i].name);
1969 r += sprintf(buf + r, "no%s ",
1970 trace_opts[i].name);
1973 r += sprintf(buf + r, "\n");
1974 WARN_ON(r >= len + 2);
1976 r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
1983 /* Try to assign a tracer specific option */
1984 static int set_tracer_option(struct tracer *trace, char *cmp, int neg)
1986 struct tracer_flags *trace_flags = trace->flags;
1987 struct tracer_opt *opts = NULL;
1991 for (i = 0; trace_flags->opts[i].name; i++) {
1992 opts = &trace_flags->opts[i];
1993 len = strlen(opts->name);
1995 if (strncmp(cmp, opts->name, len) == 0) {
1996 ret = trace->set_flag(trace_flags->val,
2002 if (!trace_flags->opts[i].name)
2005 /* Refused to handle */
2010 trace_flags->val &= ~opts->bit;
2012 trace_flags->val |= opts->bit;
2018 tracing_trace_options_write(struct file *filp, const char __user *ubuf,
2019 size_t cnt, loff_t *ppos)
2027 if (cnt >= sizeof(buf))
2030 if (copy_from_user(&buf, ubuf, cnt))
2035 if (strncmp(buf, "no", 2) == 0) {
2040 for (i = 0; trace_options[i]; i++) {
2041 int len = strlen(trace_options[i]);
2043 if (strncmp(cmp, trace_options[i], len) == 0) {
2045 trace_flags &= ~(1 << i);
2047 trace_flags |= (1 << i);
2052 /* If no option could be set, test the specific tracer options */
2053 if (!trace_options[i]) {
2054 ret = set_tracer_option(current_trace, cmp, neg);
2064 static struct file_operations tracing_iter_fops = {
2065 .open = tracing_open_generic,
2066 .read = tracing_trace_options_read,
2067 .write = tracing_trace_options_write,
2070 static const char readme_msg[] =
2071 "tracing mini-HOWTO:\n\n"
2073 "# mount -t debugfs nodev /debug\n\n"
2074 "# cat /debug/tracing/available_tracers\n"
2075 "wakeup preemptirqsoff preemptoff irqsoff ftrace sched_switch none\n\n"
2076 "# cat /debug/tracing/current_tracer\n"
2078 "# echo sched_switch > /debug/tracing/current_tracer\n"
2079 "# cat /debug/tracing/current_tracer\n"
2081 "# cat /debug/tracing/trace_options\n"
2082 "noprint-parent nosym-offset nosym-addr noverbose\n"
2083 "# echo print-parent > /debug/tracing/trace_options\n"
2084 "# echo 1 > /debug/tracing/tracing_enabled\n"
2085 "# cat /debug/tracing/trace > /tmp/trace.txt\n"
2086 "echo 0 > /debug/tracing/tracing_enabled\n"
2090 tracing_readme_read(struct file *filp, char __user *ubuf,
2091 size_t cnt, loff_t *ppos)
2093 return simple_read_from_buffer(ubuf, cnt, ppos,
2094 readme_msg, strlen(readme_msg));
2097 static struct file_operations tracing_readme_fops = {
2098 .open = tracing_open_generic,
2099 .read = tracing_readme_read,
2103 tracing_ctrl_read(struct file *filp, char __user *ubuf,
2104 size_t cnt, loff_t *ppos)
2109 r = sprintf(buf, "%u\n", tracer_enabled);
2110 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2114 tracing_ctrl_write(struct file *filp, const char __user *ubuf,
2115 size_t cnt, loff_t *ppos)
2117 struct trace_array *tr = filp->private_data;
2122 if (cnt >= sizeof(buf))
2125 if (copy_from_user(&buf, ubuf, cnt))
2130 ret = strict_strtoul(buf, 10, &val);
2136 mutex_lock(&trace_types_lock);
2137 if (tracer_enabled ^ val) {
2140 if (current_trace->start)
2141 current_trace->start(tr);
2146 if (current_trace->stop)
2147 current_trace->stop(tr);
2150 mutex_unlock(&trace_types_lock);
2158 tracing_set_trace_read(struct file *filp, char __user *ubuf,
2159 size_t cnt, loff_t *ppos)
2161 char buf[max_tracer_type_len+2];
2164 mutex_lock(&trace_types_lock);
2166 r = sprintf(buf, "%s\n", current_trace->name);
2168 r = sprintf(buf, "\n");
2169 mutex_unlock(&trace_types_lock);
2171 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2174 static int tracing_set_tracer(const char *buf)
2176 struct trace_array *tr = &global_trace;
2180 mutex_lock(&trace_types_lock);
2181 for (t = trace_types; t; t = t->next) {
2182 if (strcmp(t->name, buf) == 0)
2189 if (t == current_trace)
2192 trace_branch_disable();
2193 if (current_trace && current_trace->reset)
2194 current_trace->reset(tr);
2203 trace_branch_enable(tr);
2205 mutex_unlock(&trace_types_lock);
2211 tracing_set_trace_write(struct file *filp, const char __user *ubuf,
2212 size_t cnt, loff_t *ppos)
2214 char buf[max_tracer_type_len+1];
2221 if (cnt > max_tracer_type_len)
2222 cnt = max_tracer_type_len;
2224 if (copy_from_user(&buf, ubuf, cnt))
2229 /* strip ending whitespace. */
2230 for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
2233 err = tracing_set_tracer(buf);
2243 tracing_max_lat_read(struct file *filp, char __user *ubuf,
2244 size_t cnt, loff_t *ppos)
2246 unsigned long *ptr = filp->private_data;
2250 r = snprintf(buf, sizeof(buf), "%ld\n",
2251 *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
2252 if (r > sizeof(buf))
2254 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2258 tracing_max_lat_write(struct file *filp, const char __user *ubuf,
2259 size_t cnt, loff_t *ppos)
2261 long *ptr = filp->private_data;
2266 if (cnt >= sizeof(buf))
2269 if (copy_from_user(&buf, ubuf, cnt))
2274 ret = strict_strtoul(buf, 10, &val);
2283 static atomic_t tracing_reader;
2285 static int tracing_open_pipe(struct inode *inode, struct file *filp)
2287 struct trace_iterator *iter;
2289 if (tracing_disabled)
2292 /* We only allow for reader of the pipe */
2293 if (atomic_inc_return(&tracing_reader) != 1) {
2294 atomic_dec(&tracing_reader);
2298 /* create a buffer to store the information to pass to userspace */
2299 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2303 if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
2308 mutex_lock(&trace_types_lock);
2310 /* trace pipe does not show start of buffer */
2311 cpumask_setall(iter->started);
2313 iter->tr = &global_trace;
2314 iter->trace = current_trace;
2315 filp->private_data = iter;
2317 if (iter->trace->pipe_open)
2318 iter->trace->pipe_open(iter);
2319 mutex_unlock(&trace_types_lock);
2324 static int tracing_release_pipe(struct inode *inode, struct file *file)
2326 struct trace_iterator *iter = file->private_data;
2328 free_cpumask_var(iter->started);
2330 atomic_dec(&tracing_reader);
2336 tracing_poll_pipe(struct file *filp, poll_table *poll_table)
2338 struct trace_iterator *iter = filp->private_data;
2340 if (trace_flags & TRACE_ITER_BLOCK) {
2342 * Always select as readable when in blocking mode
2344 return POLLIN | POLLRDNORM;
2346 if (!trace_empty(iter))
2347 return POLLIN | POLLRDNORM;
2348 poll_wait(filp, &trace_wait, poll_table);
2349 if (!trace_empty(iter))
2350 return POLLIN | POLLRDNORM;
2360 tracing_read_pipe(struct file *filp, char __user *ubuf,
2361 size_t cnt, loff_t *ppos)
2363 struct trace_iterator *iter = filp->private_data;
2366 /* return any leftover data */
2367 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
2371 trace_seq_reset(&iter->seq);
2373 mutex_lock(&trace_types_lock);
2374 if (iter->trace->read) {
2375 sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
2382 while (trace_empty(iter)) {
2384 if ((filp->f_flags & O_NONBLOCK)) {
2390 * This is a make-shift waitqueue. The reason we don't use
2391 * an actual wait queue is because:
2392 * 1) we only ever have one waiter
2393 * 2) the tracing, traces all functions, we don't want
2394 * the overhead of calling wake_up and friends
2395 * (and tracing them too)
2396 * Anyway, this is really very primitive wakeup.
2398 set_current_state(TASK_INTERRUPTIBLE);
2399 iter->tr->waiter = current;
2401 mutex_unlock(&trace_types_lock);
2403 /* sleep for 100 msecs, and try again. */
2404 schedule_timeout(HZ/10);
2406 mutex_lock(&trace_types_lock);
2408 iter->tr->waiter = NULL;
2410 if (signal_pending(current)) {
2415 if (iter->trace != current_trace)
2419 * We block until we read something and tracing is disabled.
2420 * We still block if tracing is disabled, but we have never
2421 * read anything. This allows a user to cat this file, and
2422 * then enable tracing. But after we have read something,
2423 * we give an EOF when tracing is again disabled.
2425 * iter->pos will be 0 if we haven't read anything.
2427 if (!tracer_enabled && iter->pos)
2433 /* stop when tracing is finished */
2434 if (trace_empty(iter))
2437 if (cnt >= PAGE_SIZE)
2438 cnt = PAGE_SIZE - 1;
2440 /* reset all but tr, trace, and overruns */
2441 memset(&iter->seq, 0,
2442 sizeof(struct trace_iterator) -
2443 offsetof(struct trace_iterator, seq));
2446 while (find_next_entry_inc(iter) != NULL) {
2447 enum print_line_t ret;
2448 int len = iter->seq.len;
2450 ret = print_trace_line(iter);
2451 if (ret == TRACE_TYPE_PARTIAL_LINE) {
2452 /* don't print partial lines */
2453 iter->seq.len = len;
2457 trace_consume(iter);
2459 if (iter->seq.len >= cnt)
2463 /* Now copy what we have to the user */
2464 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
2465 if (iter->seq.readpos >= iter->seq.len)
2466 trace_seq_reset(&iter->seq);
2469 * If there was nothing to send to user, inspite of consuming trace
2470 * entries, go back to wait for more entries.
2476 mutex_unlock(&trace_types_lock);
2482 tracing_entries_read(struct file *filp, char __user *ubuf,
2483 size_t cnt, loff_t *ppos)
2485 struct trace_array *tr = filp->private_data;
2489 r = sprintf(buf, "%lu\n", tr->entries >> 10);
2490 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2494 tracing_entries_write(struct file *filp, const char __user *ubuf,
2495 size_t cnt, loff_t *ppos)
2501 if (cnt >= sizeof(buf))
2504 if (copy_from_user(&buf, ubuf, cnt))
2509 ret = strict_strtoul(buf, 10, &val);
2513 /* must have at least 1 entry */
2517 mutex_lock(&trace_types_lock);
2521 /* disable all cpu buffers */
2522 for_each_tracing_cpu(cpu) {
2523 if (global_trace.data[cpu])
2524 atomic_inc(&global_trace.data[cpu]->disabled);
2525 if (max_tr.data[cpu])
2526 atomic_inc(&max_tr.data[cpu]->disabled);
2529 /* value is in KB */
2532 if (val != global_trace.entries) {
2533 ret = ring_buffer_resize(global_trace.buffer, val);
2539 ret = ring_buffer_resize(max_tr.buffer, val);
2543 r = ring_buffer_resize(global_trace.buffer,
2544 global_trace.entries);
2546 /* AARGH! We are left with different
2547 * size max buffer!!!! */
2549 tracing_disabled = 1;
2554 global_trace.entries = val;
2559 /* If check pages failed, return ENOMEM */
2560 if (tracing_disabled)
2563 for_each_tracing_cpu(cpu) {
2564 if (global_trace.data[cpu])
2565 atomic_dec(&global_trace.data[cpu]->disabled);
2566 if (max_tr.data[cpu])
2567 atomic_dec(&max_tr.data[cpu]->disabled);
2571 max_tr.entries = global_trace.entries;
2572 mutex_unlock(&trace_types_lock);
2577 static int mark_printk(const char *fmt, ...)
2581 va_start(args, fmt);
2582 ret = trace_vprintk(0, -1, fmt, args);
2588 tracing_mark_write(struct file *filp, const char __user *ubuf,
2589 size_t cnt, loff_t *fpos)
2594 if (tracing_disabled)
2597 if (cnt > TRACE_BUF_SIZE)
2598 cnt = TRACE_BUF_SIZE;
2600 buf = kmalloc(cnt + 1, GFP_KERNEL);
2604 if (copy_from_user(buf, ubuf, cnt)) {
2609 /* Cut from the first nil or newline. */
2611 end = strchr(buf, '\n');
2615 cnt = mark_printk("%s\n", buf);
2622 static struct file_operations tracing_max_lat_fops = {
2623 .open = tracing_open_generic,
2624 .read = tracing_max_lat_read,
2625 .write = tracing_max_lat_write,
2628 static struct file_operations tracing_ctrl_fops = {
2629 .open = tracing_open_generic,
2630 .read = tracing_ctrl_read,
2631 .write = tracing_ctrl_write,
2634 static struct file_operations set_tracer_fops = {
2635 .open = tracing_open_generic,
2636 .read = tracing_set_trace_read,
2637 .write = tracing_set_trace_write,
2640 static struct file_operations tracing_pipe_fops = {
2641 .open = tracing_open_pipe,
2642 .poll = tracing_poll_pipe,
2643 .read = tracing_read_pipe,
2644 .release = tracing_release_pipe,
2647 static struct file_operations tracing_entries_fops = {
2648 .open = tracing_open_generic,
2649 .read = tracing_entries_read,
2650 .write = tracing_entries_write,
2653 static struct file_operations tracing_mark_fops = {
2654 .open = tracing_open_generic,
2655 .write = tracing_mark_write,
2658 #ifdef CONFIG_DYNAMIC_FTRACE
2660 int __weak ftrace_arch_read_dyn_info(char *buf, int size)
2666 tracing_read_dyn_info(struct file *filp, char __user *ubuf,
2667 size_t cnt, loff_t *ppos)
2669 static char ftrace_dyn_info_buffer[1024];
2670 static DEFINE_MUTEX(dyn_info_mutex);
2671 unsigned long *p = filp->private_data;
2672 char *buf = ftrace_dyn_info_buffer;
2673 int size = ARRAY_SIZE(ftrace_dyn_info_buffer);
2676 mutex_lock(&dyn_info_mutex);
2677 r = sprintf(buf, "%ld ", *p);
2679 r += ftrace_arch_read_dyn_info(buf+r, (size-1)-r);
2682 r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2684 mutex_unlock(&dyn_info_mutex);
2689 static struct file_operations tracing_dyn_info_fops = {
2690 .open = tracing_open_generic,
2691 .read = tracing_read_dyn_info,
2695 static struct dentry *d_tracer;
2697 struct dentry *tracing_init_dentry(void)
2704 d_tracer = debugfs_create_dir("tracing", NULL);
2706 if (!d_tracer && !once) {
2708 pr_warning("Could not create debugfs directory 'tracing'\n");
2715 #ifdef CONFIG_FTRACE_SELFTEST
2716 /* Let selftest have access to static functions in this file */
2717 #include "trace_selftest.c"
2720 static __init int tracer_init_debugfs(void)
2722 struct dentry *d_tracer;
2723 struct dentry *entry;
2725 d_tracer = tracing_init_dentry();
2727 entry = debugfs_create_file("tracing_enabled", 0644, d_tracer,
2728 &global_trace, &tracing_ctrl_fops);
2730 pr_warning("Could not create debugfs 'tracing_enabled' entry\n");
2732 entry = debugfs_create_file("trace_options", 0644, d_tracer,
2733 NULL, &tracing_iter_fops);
2735 pr_warning("Could not create debugfs 'trace_options' entry\n");
2737 entry = debugfs_create_file("tracing_cpumask", 0644, d_tracer,
2738 NULL, &tracing_cpumask_fops);
2740 pr_warning("Could not create debugfs 'tracing_cpumask' entry\n");
2742 entry = debugfs_create_file("latency_trace", 0444, d_tracer,
2743 &global_trace, &tracing_lt_fops);
2745 pr_warning("Could not create debugfs 'latency_trace' entry\n");
2747 entry = debugfs_create_file("trace", 0444, d_tracer,
2748 &global_trace, &tracing_fops);
2750 pr_warning("Could not create debugfs 'trace' entry\n");
2752 entry = debugfs_create_file("available_tracers", 0444, d_tracer,
2753 &global_trace, &show_traces_fops);
2755 pr_warning("Could not create debugfs 'available_tracers' entry\n");
2757 entry = debugfs_create_file("current_tracer", 0444, d_tracer,
2758 &global_trace, &set_tracer_fops);
2760 pr_warning("Could not create debugfs 'current_tracer' entry\n");
2762 entry = debugfs_create_file("tracing_max_latency", 0644, d_tracer,
2763 &tracing_max_latency,
2764 &tracing_max_lat_fops);
2766 pr_warning("Could not create debugfs "
2767 "'tracing_max_latency' entry\n");
2769 entry = debugfs_create_file("tracing_thresh", 0644, d_tracer,
2770 &tracing_thresh, &tracing_max_lat_fops);
2772 pr_warning("Could not create debugfs "
2773 "'tracing_thresh' entry\n");
2774 entry = debugfs_create_file("README", 0644, d_tracer,
2775 NULL, &tracing_readme_fops);
2777 pr_warning("Could not create debugfs 'README' entry\n");
2779 entry = debugfs_create_file("trace_pipe", 0644, d_tracer,
2780 NULL, &tracing_pipe_fops);
2782 pr_warning("Could not create debugfs "
2783 "'trace_pipe' entry\n");
2785 entry = debugfs_create_file("buffer_size_kb", 0644, d_tracer,
2786 &global_trace, &tracing_entries_fops);
2788 pr_warning("Could not create debugfs "
2789 "'buffer_size_kb' entry\n");
2791 entry = debugfs_create_file("trace_marker", 0220, d_tracer,
2792 NULL, &tracing_mark_fops);
2794 pr_warning("Could not create debugfs "
2795 "'trace_marker' entry\n");
2797 #ifdef CONFIG_DYNAMIC_FTRACE
2798 entry = debugfs_create_file("dyn_ftrace_total_info", 0444, d_tracer,
2799 &ftrace_update_tot_cnt,
2800 &tracing_dyn_info_fops);
2802 pr_warning("Could not create debugfs "
2803 "'dyn_ftrace_total_info' entry\n");
2805 #ifdef CONFIG_SYSPROF_TRACER
2806 init_tracer_sysprof_debugfs(d_tracer);
2811 int trace_vprintk(unsigned long ip, int depth, const char *fmt, va_list args)
2813 static DEFINE_SPINLOCK(trace_buf_lock);
2814 static char trace_buf[TRACE_BUF_SIZE];
2816 struct ring_buffer_event *event;
2817 struct trace_array *tr = &global_trace;
2818 struct trace_array_cpu *data;
2819 int cpu, len = 0, size, pc;
2820 struct print_entry *entry;
2821 unsigned long irq_flags;
2823 if (tracing_disabled || tracing_selftest_running)
2826 pc = preempt_count();
2827 preempt_disable_notrace();
2828 cpu = raw_smp_processor_id();
2829 data = tr->data[cpu];
2831 if (unlikely(atomic_read(&data->disabled)))
2834 pause_graph_tracing();
2835 spin_lock_irqsave(&trace_buf_lock, irq_flags);
2836 len = vsnprintf(trace_buf, TRACE_BUF_SIZE, fmt, args);
2838 len = min(len, TRACE_BUF_SIZE-1);
2841 size = sizeof(*entry) + len + 1;
2842 event = trace_buffer_lock_reserve(tr, TRACE_PRINT, size, irq_flags, pc);
2845 entry = ring_buffer_event_data(event);
2847 entry->depth = depth;
2849 memcpy(&entry->buf, trace_buf, len);
2850 entry->buf[len] = 0;
2851 ring_buffer_unlock_commit(tr->buffer, event);
2854 spin_unlock_irqrestore(&trace_buf_lock, irq_flags);
2855 unpause_graph_tracing();
2857 preempt_enable_notrace();
2861 EXPORT_SYMBOL_GPL(trace_vprintk);
2863 int __ftrace_printk(unsigned long ip, const char *fmt, ...)
2868 if (!(trace_flags & TRACE_ITER_PRINTK))
2872 ret = trace_vprintk(ip, task_curr_ret_stack(current), fmt, ap);
2876 EXPORT_SYMBOL_GPL(__ftrace_printk);
2878 int __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap)
2880 if (!(trace_flags & TRACE_ITER_PRINTK))
2883 return trace_vprintk(ip, task_curr_ret_stack(current), fmt, ap);
2885 EXPORT_SYMBOL_GPL(__ftrace_vprintk);
2887 static int trace_panic_handler(struct notifier_block *this,
2888 unsigned long event, void *unused)
2890 if (ftrace_dump_on_oops)
2895 static struct notifier_block trace_panic_notifier = {
2896 .notifier_call = trace_panic_handler,
2898 .priority = 150 /* priority: INT_MAX >= x >= 0 */
2901 static int trace_die_handler(struct notifier_block *self,
2907 if (ftrace_dump_on_oops)
2916 static struct notifier_block trace_die_notifier = {
2917 .notifier_call = trace_die_handler,
2922 * printk is set to max of 1024, we really don't need it that big.
2923 * Nothing should be printing 1000 characters anyway.
2925 #define TRACE_MAX_PRINT 1000
2928 * Define here KERN_TRACE so that we have one place to modify
2929 * it if we decide to change what log level the ftrace dump
2932 #define KERN_TRACE KERN_EMERG
2935 trace_printk_seq(struct trace_seq *s)
2937 /* Probably should print a warning here. */
2941 /* should be zero ended, but we are paranoid. */
2942 s->buffer[s->len] = 0;
2944 printk(KERN_TRACE "%s", s->buffer);
2949 void ftrace_dump(void)
2951 static DEFINE_SPINLOCK(ftrace_dump_lock);
2952 /* use static because iter can be a bit big for the stack */
2953 static struct trace_iterator iter;
2954 static int dump_ran;
2955 unsigned long flags;
2959 spin_lock_irqsave(&ftrace_dump_lock, flags);
2965 /* No turning back! */
2969 for_each_tracing_cpu(cpu) {
2970 atomic_inc(&global_trace.data[cpu]->disabled);
2973 /* don't look at user memory in panic mode */
2974 trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
2976 printk(KERN_TRACE "Dumping ftrace buffer:\n");
2978 iter.tr = &global_trace;
2979 iter.trace = current_trace;
2982 * We need to stop all tracing on all CPUS to read the
2983 * the next buffer. This is a bit expensive, but is
2984 * not done often. We fill all what we can read,
2985 * and then release the locks again.
2988 while (!trace_empty(&iter)) {
2991 printk(KERN_TRACE "---------------------------------\n");
2995 /* reset all but tr, trace, and overruns */
2996 memset(&iter.seq, 0,
2997 sizeof(struct trace_iterator) -
2998 offsetof(struct trace_iterator, seq));
2999 iter.iter_flags |= TRACE_FILE_LAT_FMT;
3002 if (find_next_entry_inc(&iter) != NULL) {
3003 print_trace_line(&iter);
3004 trace_consume(&iter);
3007 trace_printk_seq(&iter.seq);
3011 printk(KERN_TRACE " (ftrace buffer empty)\n");
3013 printk(KERN_TRACE "---------------------------------\n");
3016 spin_unlock_irqrestore(&ftrace_dump_lock, flags);
3019 __init static int tracer_alloc_buffers(void)
3021 struct trace_array_cpu *data;
3025 if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
3028 if (!alloc_cpumask_var(&tracing_cpumask, GFP_KERNEL))
3029 goto out_free_buffer_mask;
3031 cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
3032 cpumask_copy(tracing_cpumask, cpu_all_mask);
3034 /* TODO: make the number of buffers hot pluggable with CPUS */
3035 global_trace.buffer = ring_buffer_alloc(trace_buf_size,
3036 TRACE_BUFFER_FLAGS);
3037 if (!global_trace.buffer) {
3038 printk(KERN_ERR "tracer: failed to allocate ring buffer!\n");
3040 goto out_free_cpumask;
3042 global_trace.entries = ring_buffer_size(global_trace.buffer);
3045 #ifdef CONFIG_TRACER_MAX_TRACE
3046 max_tr.buffer = ring_buffer_alloc(trace_buf_size,
3047 TRACE_BUFFER_FLAGS);
3048 if (!max_tr.buffer) {
3049 printk(KERN_ERR "tracer: failed to allocate max ring buffer!\n");
3051 ring_buffer_free(global_trace.buffer);
3052 goto out_free_cpumask;
3054 max_tr.entries = ring_buffer_size(max_tr.buffer);
3055 WARN_ON(max_tr.entries != global_trace.entries);
3058 /* Allocate the first page for all buffers */
3059 for_each_tracing_cpu(i) {
3060 data = global_trace.data[i] = &per_cpu(global_trace_cpu, i);
3061 max_tr.data[i] = &per_cpu(max_data, i);
3064 trace_init_cmdlines();
3066 register_tracer(&nop_trace);
3067 current_trace = &nop_trace;
3068 #ifdef CONFIG_BOOT_TRACER
3069 register_tracer(&boot_tracer);
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);
3088 __init static int clear_boot_tracer(void)
3091 * The default tracer at boot buffer is an init section.
3092 * This function is called in lateinit. If we did not
3093 * find the boot tracer, then clear it out, to prevent
3094 * later registration from accessing the buffer that is
3095 * about to be freed.
3097 if (!default_bootup_tracer)
3100 printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n",
3101 default_bootup_tracer);
3102 default_bootup_tracer = NULL;
3107 early_initcall(tracer_alloc_buffers);
3108 fs_initcall(tracer_init_debugfs);
3109 late_initcall(clear_boot_tracer);