Merge branch 'tip/tracing/ftrace' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux-2.6.git] / kernel / trace / trace.c
1 /*
2  * ring buffer based function tracer
3  *
4  * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
5  * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
6  *
7  * Originally taken from the RT patch by:
8  *    Arnaldo Carvalho de Melo <acme@redhat.com>
9  *
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
13  */
14 #include <linux/ring_buffer.h>
15 #include <linux/utsrelease.h>
16 #include <linux/stacktrace.h>
17 #include <linux/writeback.h>
18 #include <linux/kallsyms.h>
19 #include <linux/seq_file.h>
20 #include <linux/notifier.h>
21 #include <linux/irqflags.h>
22 #include <linux/debugfs.h>
23 #include <linux/pagemap.h>
24 #include <linux/hardirq.h>
25 #include <linux/linkage.h>
26 #include <linux/uaccess.h>
27 #include <linux/kprobes.h>
28 #include <linux/ftrace.h>
29 #include <linux/module.h>
30 #include <linux/percpu.h>
31 #include <linux/splice.h>
32 #include <linux/kdebug.h>
33 #include <linux/ctype.h>
34 #include <linux/init.h>
35 #include <linux/poll.h>
36 #include <linux/gfp.h>
37 #include <linux/fs.h>
38
39 #include "trace.h"
40 #include "trace_output.h"
41
42 #define TRACE_BUFFER_FLAGS      (RB_FL_OVERWRITE)
43
44 unsigned long __read_mostly     tracing_max_latency;
45 unsigned long __read_mostly     tracing_thresh;
46
47 /*
48  * On boot up, the ring buffer is set to the minimum size, so that
49  * we do not waste memory on systems that are not using tracing.
50  */
51 static int ring_buffer_expanded;
52
53 /*
54  * We need to change this state when a selftest is running.
55  * A selftest will lurk into the ring-buffer to count the
56  * entries inserted during the selftest although some concurrent
57  * insertions into the ring-buffer such as trace_printk could occurred
58  * at the same time, giving false positive or negative results.
59  */
60 static bool __read_mostly tracing_selftest_running;
61
62 /*
63  * If a tracer is running, we do not want to run SELFTEST.
64  */
65 static bool __read_mostly tracing_selftest_disabled;
66
67 /* For tracers that don't implement custom flags */
68 static struct tracer_opt dummy_tracer_opt[] = {
69         { }
70 };
71
72 static struct tracer_flags dummy_tracer_flags = {
73         .val = 0,
74         .opts = dummy_tracer_opt
75 };
76
77 static int dummy_set_flag(u32 old_flags, u32 bit, int set)
78 {
79         return 0;
80 }
81
82 /*
83  * Kill all tracing for good (never come back).
84  * It is initialized to 1 but will turn to zero if the initialization
85  * of the tracer is successful. But that is the only place that sets
86  * this back to zero.
87  */
88 static int tracing_disabled = 1;
89
90 static DEFINE_PER_CPU(local_t, ftrace_cpu_disabled);
91
92 static inline void ftrace_disable_cpu(void)
93 {
94         preempt_disable();
95         local_inc(&__get_cpu_var(ftrace_cpu_disabled));
96 }
97
98 static inline void ftrace_enable_cpu(void)
99 {
100         local_dec(&__get_cpu_var(ftrace_cpu_disabled));
101         preempt_enable();
102 }
103
104 static cpumask_var_t __read_mostly      tracing_buffer_mask;
105
106 /* Define which cpu buffers are currently read in trace_pipe */
107 static cpumask_var_t                    tracing_reader_cpumask;
108
109 #define for_each_tracing_cpu(cpu)       \
110         for_each_cpu(cpu, tracing_buffer_mask)
111
112 /*
113  * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
114  *
115  * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
116  * is set, then ftrace_dump is called. This will output the contents
117  * of the ftrace buffers to the console.  This is very useful for
118  * capturing traces that lead to crashes and outputing it to a
119  * serial console.
120  *
121  * It is default off, but you can enable it with either specifying
122  * "ftrace_dump_on_oops" in the kernel command line, or setting
123  * /proc/sys/kernel/ftrace_dump_on_oops to true.
124  */
125 int ftrace_dump_on_oops;
126
127 static int tracing_set_tracer(const char *buf);
128
129 #define BOOTUP_TRACER_SIZE              100
130 static char bootup_tracer_buf[BOOTUP_TRACER_SIZE] __initdata;
131 static char *default_bootup_tracer;
132
133 static int __init set_ftrace(char *str)
134 {
135         strncpy(bootup_tracer_buf, str, BOOTUP_TRACER_SIZE);
136         default_bootup_tracer = bootup_tracer_buf;
137         /* We are using ftrace early, expand it */
138         ring_buffer_expanded = 1;
139         return 1;
140 }
141 __setup("ftrace=", set_ftrace);
142
143 static int __init set_ftrace_dump_on_oops(char *str)
144 {
145         ftrace_dump_on_oops = 1;
146         return 1;
147 }
148 __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
149
150 long
151 ns2usecs(cycle_t nsec)
152 {
153         nsec += 500;
154         do_div(nsec, 1000);
155         return nsec;
156 }
157
158 cycle_t ftrace_now(int cpu)
159 {
160         u64 ts = ring_buffer_time_stamp(cpu);
161         ring_buffer_normalize_time_stamp(cpu, &ts);
162         return ts;
163 }
164
165 /*
166  * The global_trace is the descriptor that holds the tracing
167  * buffers for the live tracing. For each CPU, it contains
168  * a link list of pages that will store trace entries. The
169  * page descriptor of the pages in the memory is used to hold
170  * the link list by linking the lru item in the page descriptor
171  * to each of the pages in the buffer per CPU.
172  *
173  * For each active CPU there is a data field that holds the
174  * pages for the buffer for that CPU. Each CPU has the same number
175  * of pages allocated for its buffer.
176  */
177 static struct trace_array       global_trace;
178
179 static DEFINE_PER_CPU(struct trace_array_cpu, global_trace_cpu);
180
181 /*
182  * The max_tr is used to snapshot the global_trace when a maximum
183  * latency is reached. Some tracers will use this to store a maximum
184  * trace while it continues examining live traces.
185  *
186  * The buffers for the max_tr are set up the same as the global_trace.
187  * When a snapshot is taken, the link list of the max_tr is swapped
188  * with the link list of the global_trace and the buffers are reset for
189  * the global_trace so the tracing can continue.
190  */
191 static struct trace_array       max_tr;
192
193 static DEFINE_PER_CPU(struct trace_array_cpu, max_data);
194
195 /* tracer_enabled is used to toggle activation of a tracer */
196 static int                      tracer_enabled = 1;
197
198 /**
199  * tracing_is_enabled - return tracer_enabled status
200  *
201  * This function is used by other tracers to know the status
202  * of the tracer_enabled flag.  Tracers may use this function
203  * to know if it should enable their features when starting
204  * up. See irqsoff tracer for an example (start_irqsoff_tracer).
205  */
206 int tracing_is_enabled(void)
207 {
208         return tracer_enabled;
209 }
210
211 /*
212  * trace_buf_size is the size in bytes that is allocated
213  * for a buffer. Note, the number of bytes is always rounded
214  * to page size.
215  *
216  * This number is purposely set to a low number of 16384.
217  * If the dump on oops happens, it will be much appreciated
218  * to not have to wait for all that output. Anyway this can be
219  * boot time and run time configurable.
220  */
221 #define TRACE_BUF_SIZE_DEFAULT  1441792UL /* 16384 * 88 (sizeof(entry)) */
222
223 static unsigned long            trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
224
225 /* trace_types holds a link list of available tracers. */
226 static struct tracer            *trace_types __read_mostly;
227
228 /* current_trace points to the tracer that is currently active */
229 static struct tracer            *current_trace __read_mostly;
230
231 /*
232  * max_tracer_type_len is used to simplify the allocating of
233  * buffers to read userspace tracer names. We keep track of
234  * the longest tracer name registered.
235  */
236 static int                      max_tracer_type_len;
237
238 /*
239  * trace_types_lock is used to protect the trace_types list.
240  * This lock is also used to keep user access serialized.
241  * Accesses from userspace will grab this lock while userspace
242  * activities happen inside the kernel.
243  */
244 static DEFINE_MUTEX(trace_types_lock);
245
246 /* trace_wait is a waitqueue for tasks blocked on trace_poll */
247 static DECLARE_WAIT_QUEUE_HEAD(trace_wait);
248
249 /* trace_flags holds trace_options default values */
250 unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK |
251         TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO;
252
253 /**
254  * trace_wake_up - wake up tasks waiting for trace input
255  *
256  * Simply wakes up any task that is blocked on the trace_wait
257  * queue. These is used with trace_poll for tasks polling the trace.
258  */
259 void trace_wake_up(void)
260 {
261         /*
262          * The runqueue_is_locked() can fail, but this is the best we
263          * have for now:
264          */
265         if (!(trace_flags & TRACE_ITER_BLOCK) && !runqueue_is_locked())
266                 wake_up(&trace_wait);
267 }
268
269 static int __init set_buf_size(char *str)
270 {
271         unsigned long buf_size;
272         int ret;
273
274         if (!str)
275                 return 0;
276         ret = strict_strtoul(str, 0, &buf_size);
277         /* nr_entries can not be zero */
278         if (ret < 0 || buf_size == 0)
279                 return 0;
280         trace_buf_size = buf_size;
281         return 1;
282 }
283 __setup("trace_buf_size=", set_buf_size);
284
285 unsigned long nsecs_to_usecs(unsigned long nsecs)
286 {
287         return nsecs / 1000;
288 }
289
290 /* These must match the bit postions in trace_iterator_flags */
291 static const char *trace_options[] = {
292         "print-parent",
293         "sym-offset",
294         "sym-addr",
295         "verbose",
296         "raw",
297         "hex",
298         "bin",
299         "block",
300         "stacktrace",
301         "sched-tree",
302         "trace_printk",
303         "ftrace_preempt",
304         "branch",
305         "annotate",
306         "userstacktrace",
307         "sym-userobj",
308         "printk-msg-only",
309         "context-info",
310         "latency-format",
311         NULL
312 };
313
314 /*
315  * ftrace_max_lock is used to protect the swapping of buffers
316  * when taking a max snapshot. The buffers themselves are
317  * protected by per_cpu spinlocks. But the action of the swap
318  * needs its own lock.
319  *
320  * This is defined as a raw_spinlock_t in order to help
321  * with performance when lockdep debugging is enabled.
322  */
323 static raw_spinlock_t ftrace_max_lock =
324         (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
325
326 /*
327  * Copy the new maximum trace into the separate maximum-trace
328  * structure. (this way the maximum trace is permanently saved,
329  * for later retrieval via /debugfs/tracing/latency_trace)
330  */
331 static void
332 __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
333 {
334         struct trace_array_cpu *data = tr->data[cpu];
335
336         max_tr.cpu = cpu;
337         max_tr.time_start = data->preempt_timestamp;
338
339         data = max_tr.data[cpu];
340         data->saved_latency = tracing_max_latency;
341
342         memcpy(data->comm, tsk->comm, TASK_COMM_LEN);
343         data->pid = tsk->pid;
344         data->uid = task_uid(tsk);
345         data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
346         data->policy = tsk->policy;
347         data->rt_priority = tsk->rt_priority;
348
349         /* record this tasks comm */
350         tracing_record_cmdline(tsk);
351 }
352
353 ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
354 {
355         int len;
356         int ret;
357
358         if (!cnt)
359                 return 0;
360
361         if (s->len <= s->readpos)
362                 return -EBUSY;
363
364         len = s->len - s->readpos;
365         if (cnt > len)
366                 cnt = len;
367         ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
368         if (ret == cnt)
369                 return -EFAULT;
370
371         cnt -= ret;
372
373         s->readpos += cnt;
374         return cnt;
375 }
376
377 ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
378 {
379         int len;
380         void *ret;
381
382         if (s->len <= s->readpos)
383                 return -EBUSY;
384
385         len = s->len - s->readpos;
386         if (cnt > len)
387                 cnt = len;
388         ret = memcpy(buf, s->buffer + s->readpos, cnt);
389         if (!ret)
390                 return -EFAULT;
391
392         s->readpos += cnt;
393         return cnt;
394 }
395
396 static void
397 trace_print_seq(struct seq_file *m, struct trace_seq *s)
398 {
399         int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len;
400
401         s->buffer[len] = 0;
402         seq_puts(m, s->buffer);
403
404         trace_seq_init(s);
405 }
406
407 /**
408  * update_max_tr - snapshot all trace buffers from global_trace to max_tr
409  * @tr: tracer
410  * @tsk: the task with the latency
411  * @cpu: The cpu that initiated the trace.
412  *
413  * Flip the buffers between the @tr and the max_tr and record information
414  * about which task was the cause of this latency.
415  */
416 void
417 update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
418 {
419         struct ring_buffer *buf = tr->buffer;
420
421         WARN_ON_ONCE(!irqs_disabled());
422         __raw_spin_lock(&ftrace_max_lock);
423
424         tr->buffer = max_tr.buffer;
425         max_tr.buffer = buf;
426
427         ftrace_disable_cpu();
428         ring_buffer_reset(tr->buffer);
429         ftrace_enable_cpu();
430
431         __update_max_tr(tr, tsk, cpu);
432         __raw_spin_unlock(&ftrace_max_lock);
433 }
434
435 /**
436  * update_max_tr_single - only copy one trace over, and reset the rest
437  * @tr - tracer
438  * @tsk - task with the latency
439  * @cpu - the cpu of the buffer to copy.
440  *
441  * Flip the trace of a single CPU buffer between the @tr and the max_tr.
442  */
443 void
444 update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
445 {
446         int ret;
447
448         WARN_ON_ONCE(!irqs_disabled());
449         __raw_spin_lock(&ftrace_max_lock);
450
451         ftrace_disable_cpu();
452
453         ring_buffer_reset(max_tr.buffer);
454         ret = ring_buffer_swap_cpu(max_tr.buffer, tr->buffer, cpu);
455
456         ftrace_enable_cpu();
457
458         WARN_ON_ONCE(ret && ret != -EAGAIN);
459
460         __update_max_tr(tr, tsk, cpu);
461         __raw_spin_unlock(&ftrace_max_lock);
462 }
463
464 /**
465  * register_tracer - register a tracer with the ftrace system.
466  * @type - the plugin for the tracer
467  *
468  * Register a new plugin tracer.
469  */
470 int register_tracer(struct tracer *type)
471 __releases(kernel_lock)
472 __acquires(kernel_lock)
473 {
474         struct tracer *t;
475         int len;
476         int ret = 0;
477
478         if (!type->name) {
479                 pr_info("Tracer must have a name\n");
480                 return -1;
481         }
482
483         /*
484          * When this gets called we hold the BKL which means that
485          * preemption is disabled. Various trace selftests however
486          * need to disable and enable preemption for successful tests.
487          * So we drop the BKL here and grab it after the tests again.
488          */
489         unlock_kernel();
490         mutex_lock(&trace_types_lock);
491
492         tracing_selftest_running = true;
493
494         for (t = trace_types; t; t = t->next) {
495                 if (strcmp(type->name, t->name) == 0) {
496                         /* already found */
497                         pr_info("Trace %s already registered\n",
498                                 type->name);
499                         ret = -1;
500                         goto out;
501                 }
502         }
503
504         if (!type->set_flag)
505                 type->set_flag = &dummy_set_flag;
506         if (!type->flags)
507                 type->flags = &dummy_tracer_flags;
508         else
509                 if (!type->flags->opts)
510                         type->flags->opts = dummy_tracer_opt;
511         if (!type->wait_pipe)
512                 type->wait_pipe = default_wait_pipe;
513
514
515 #ifdef CONFIG_FTRACE_STARTUP_TEST
516         if (type->selftest && !tracing_selftest_disabled) {
517                 struct tracer *saved_tracer = current_trace;
518                 struct trace_array *tr = &global_trace;
519                 int i;
520
521                 /*
522                  * Run a selftest on this tracer.
523                  * Here we reset the trace buffer, and set the current
524                  * tracer to be this tracer. The tracer can then run some
525                  * internal tracing to verify that everything is in order.
526                  * If we fail, we do not register this tracer.
527                  */
528                 for_each_tracing_cpu(i)
529                         tracing_reset(tr, i);
530
531                 current_trace = type;
532                 /* the test is responsible for initializing and enabling */
533                 pr_info("Testing tracer %s: ", type->name);
534                 ret = type->selftest(type, tr);
535                 /* the test is responsible for resetting too */
536                 current_trace = saved_tracer;
537                 if (ret) {
538                         printk(KERN_CONT "FAILED!\n");
539                         goto out;
540                 }
541                 /* Only reset on passing, to avoid touching corrupted buffers */
542                 for_each_tracing_cpu(i)
543                         tracing_reset(tr, i);
544
545                 printk(KERN_CONT "PASSED\n");
546         }
547 #endif
548
549         type->next = trace_types;
550         trace_types = type;
551         len = strlen(type->name);
552         if (len > max_tracer_type_len)
553                 max_tracer_type_len = len;
554
555  out:
556         tracing_selftest_running = false;
557         mutex_unlock(&trace_types_lock);
558
559         if (ret || !default_bootup_tracer)
560                 goto out_unlock;
561
562         if (strncmp(default_bootup_tracer, type->name, BOOTUP_TRACER_SIZE))
563                 goto out_unlock;
564
565         printk(KERN_INFO "Starting tracer '%s'\n", type->name);
566         /* Do we want this tracer to start on bootup? */
567         tracing_set_tracer(type->name);
568         default_bootup_tracer = NULL;
569         /* disable other selftests, since this will break it. */
570         tracing_selftest_disabled = 1;
571 #ifdef CONFIG_FTRACE_STARTUP_TEST
572         printk(KERN_INFO "Disabling FTRACE selftests due to running tracer '%s'\n",
573                type->name);
574 #endif
575
576  out_unlock:
577         lock_kernel();
578         return ret;
579 }
580
581 void unregister_tracer(struct tracer *type)
582 {
583         struct tracer **t;
584         int len;
585
586         mutex_lock(&trace_types_lock);
587         for (t = &trace_types; *t; t = &(*t)->next) {
588                 if (*t == type)
589                         goto found;
590         }
591         pr_info("Trace %s not registered\n", type->name);
592         goto out;
593
594  found:
595         *t = (*t)->next;
596
597         if (type == current_trace && tracer_enabled) {
598                 tracer_enabled = 0;
599                 tracing_stop();
600                 if (current_trace->stop)
601                         current_trace->stop(&global_trace);
602                 current_trace = &nop_trace;
603         }
604
605         if (strlen(type->name) != max_tracer_type_len)
606                 goto out;
607
608         max_tracer_type_len = 0;
609         for (t = &trace_types; *t; t = &(*t)->next) {
610                 len = strlen((*t)->name);
611                 if (len > max_tracer_type_len)
612                         max_tracer_type_len = len;
613         }
614  out:
615         mutex_unlock(&trace_types_lock);
616 }
617
618 void tracing_reset(struct trace_array *tr, int cpu)
619 {
620         ftrace_disable_cpu();
621         ring_buffer_reset_cpu(tr->buffer, cpu);
622         ftrace_enable_cpu();
623 }
624
625 void tracing_reset_online_cpus(struct trace_array *tr)
626 {
627         int cpu;
628
629         tr->time_start = ftrace_now(tr->cpu);
630
631         for_each_online_cpu(cpu)
632                 tracing_reset(tr, cpu);
633 }
634
635 #define SAVED_CMDLINES 128
636 static unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
637 static unsigned map_cmdline_to_pid[SAVED_CMDLINES];
638 static char saved_cmdlines[SAVED_CMDLINES][TASK_COMM_LEN];
639 static int cmdline_idx;
640 static raw_spinlock_t trace_cmdline_lock = __RAW_SPIN_LOCK_UNLOCKED;
641
642 /* temporary disable recording */
643 static atomic_t trace_record_cmdline_disabled __read_mostly;
644
645 static void trace_init_cmdlines(void)
646 {
647         memset(&map_pid_to_cmdline, -1, sizeof(map_pid_to_cmdline));
648         memset(&map_cmdline_to_pid, -1, sizeof(map_cmdline_to_pid));
649         cmdline_idx = 0;
650 }
651
652 static int trace_stop_count;
653 static DEFINE_SPINLOCK(tracing_start_lock);
654
655 /**
656  * ftrace_off_permanent - disable all ftrace code permanently
657  *
658  * This should only be called when a serious anomally has
659  * been detected.  This will turn off the function tracing,
660  * ring buffers, and other tracing utilites. It takes no
661  * locks and can be called from any context.
662  */
663 void ftrace_off_permanent(void)
664 {
665         tracing_disabled = 1;
666         ftrace_stop();
667         tracing_off_permanent();
668 }
669
670 /**
671  * tracing_start - quick start of the tracer
672  *
673  * If tracing is enabled but was stopped by tracing_stop,
674  * this will start the tracer back up.
675  */
676 void tracing_start(void)
677 {
678         struct ring_buffer *buffer;
679         unsigned long flags;
680
681         if (tracing_disabled)
682                 return;
683
684         spin_lock_irqsave(&tracing_start_lock, flags);
685         if (--trace_stop_count) {
686                 if (trace_stop_count < 0) {
687                         /* Someone screwed up their debugging */
688                         WARN_ON_ONCE(1);
689                         trace_stop_count = 0;
690                 }
691                 goto out;
692         }
693
694
695         buffer = global_trace.buffer;
696         if (buffer)
697                 ring_buffer_record_enable(buffer);
698
699         buffer = max_tr.buffer;
700         if (buffer)
701                 ring_buffer_record_enable(buffer);
702
703         ftrace_start();
704  out:
705         spin_unlock_irqrestore(&tracing_start_lock, flags);
706 }
707
708 /**
709  * tracing_stop - quick stop of the tracer
710  *
711  * Light weight way to stop tracing. Use in conjunction with
712  * tracing_start.
713  */
714 void tracing_stop(void)
715 {
716         struct ring_buffer *buffer;
717         unsigned long flags;
718
719         ftrace_stop();
720         spin_lock_irqsave(&tracing_start_lock, flags);
721         if (trace_stop_count++)
722                 goto out;
723
724         buffer = global_trace.buffer;
725         if (buffer)
726                 ring_buffer_record_disable(buffer);
727
728         buffer = max_tr.buffer;
729         if (buffer)
730                 ring_buffer_record_disable(buffer);
731
732  out:
733         spin_unlock_irqrestore(&tracing_start_lock, flags);
734 }
735
736 void trace_stop_cmdline_recording(void);
737
738 static void trace_save_cmdline(struct task_struct *tsk)
739 {
740         unsigned map;
741         unsigned idx;
742
743         if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT))
744                 return;
745
746         /*
747          * It's not the end of the world if we don't get
748          * the lock, but we also don't want to spin
749          * nor do we want to disable interrupts,
750          * so if we miss here, then better luck next time.
751          */
752         if (!__raw_spin_trylock(&trace_cmdline_lock))
753                 return;
754
755         idx = map_pid_to_cmdline[tsk->pid];
756         if (idx >= SAVED_CMDLINES) {
757                 idx = (cmdline_idx + 1) % SAVED_CMDLINES;
758
759                 map = map_cmdline_to_pid[idx];
760                 if (map <= PID_MAX_DEFAULT)
761                         map_pid_to_cmdline[map] = (unsigned)-1;
762
763                 map_pid_to_cmdline[tsk->pid] = idx;
764
765                 cmdline_idx = idx;
766         }
767
768         memcpy(&saved_cmdlines[idx], tsk->comm, TASK_COMM_LEN);
769
770         __raw_spin_unlock(&trace_cmdline_lock);
771 }
772
773 void trace_find_cmdline(int pid, char comm[])
774 {
775         unsigned map;
776
777         if (!pid) {
778                 strcpy(comm, "<idle>");
779                 return;
780         }
781
782         if (pid > PID_MAX_DEFAULT) {
783                 strcpy(comm, "<...>");
784                 return;
785         }
786
787         __raw_spin_lock(&trace_cmdline_lock);
788         map = map_pid_to_cmdline[pid];
789         if (map >= SAVED_CMDLINES)
790                 goto out;
791
792         strcpy(comm, saved_cmdlines[map]);
793
794  out:
795         __raw_spin_unlock(&trace_cmdline_lock);
796 }
797
798 void tracing_record_cmdline(struct task_struct *tsk)
799 {
800         if (atomic_read(&trace_record_cmdline_disabled) || !tracing_is_on())
801                 return;
802
803         trace_save_cmdline(tsk);
804 }
805
806 void
807 tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
808                              int pc)
809 {
810         struct task_struct *tsk = current;
811
812         entry->preempt_count            = pc & 0xff;
813         entry->pid                      = (tsk) ? tsk->pid : 0;
814         entry->tgid                     = (tsk) ? tsk->tgid : 0;
815         entry->flags =
816 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
817                 (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
818 #else
819                 TRACE_FLAG_IRQS_NOSUPPORT |
820 #endif
821                 ((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
822                 ((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
823                 (need_resched() ? TRACE_FLAG_NEED_RESCHED : 0);
824 }
825
826 struct ring_buffer_event *trace_buffer_lock_reserve(struct trace_array *tr,
827                                                     unsigned char type,
828                                                     unsigned long len,
829                                                     unsigned long flags, int pc)
830 {
831         struct ring_buffer_event *event;
832
833         event = ring_buffer_lock_reserve(tr->buffer, len);
834         if (event != NULL) {
835                 struct trace_entry *ent = ring_buffer_event_data(event);
836
837                 tracing_generic_entry_update(ent, flags, pc);
838                 ent->type = type;
839         }
840
841         return event;
842 }
843 static void ftrace_trace_stack(struct trace_array *tr,
844                                unsigned long flags, int skip, int pc);
845 static void ftrace_trace_userstack(struct trace_array *tr,
846                                    unsigned long flags, int pc);
847
848 void trace_buffer_unlock_commit(struct trace_array *tr,
849                                 struct ring_buffer_event *event,
850                                 unsigned long flags, int pc)
851 {
852         ring_buffer_unlock_commit(tr->buffer, event);
853
854         ftrace_trace_stack(tr, flags, 6, pc);
855         ftrace_trace_userstack(tr, flags, pc);
856         trace_wake_up();
857 }
858
859 struct ring_buffer_event *
860 trace_current_buffer_lock_reserve(unsigned char type, unsigned long len,
861                                   unsigned long flags, int pc)
862 {
863         return trace_buffer_lock_reserve(&global_trace,
864                                          type, len, flags, pc);
865 }
866
867 void trace_current_buffer_unlock_commit(struct ring_buffer_event *event,
868                                         unsigned long flags, int pc)
869 {
870         return trace_buffer_unlock_commit(&global_trace, event, flags, pc);
871 }
872
873 void
874 trace_function(struct trace_array *tr,
875                unsigned long ip, unsigned long parent_ip, unsigned long flags,
876                int pc)
877 {
878         struct ring_buffer_event *event;
879         struct ftrace_entry *entry;
880
881         /* If we are reading the ring buffer, don't trace */
882         if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
883                 return;
884
885         event = trace_buffer_lock_reserve(tr, TRACE_FN, sizeof(*entry),
886                                           flags, pc);
887         if (!event)
888                 return;
889         entry   = ring_buffer_event_data(event);
890         entry->ip                       = ip;
891         entry->parent_ip                = parent_ip;
892         ring_buffer_unlock_commit(tr->buffer, event);
893 }
894
895 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
896 static void __trace_graph_entry(struct trace_array *tr,
897                                 struct ftrace_graph_ent *trace,
898                                 unsigned long flags,
899                                 int pc)
900 {
901         struct ring_buffer_event *event;
902         struct ftrace_graph_ent_entry *entry;
903
904         if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
905                 return;
906
907         event = trace_buffer_lock_reserve(&global_trace, TRACE_GRAPH_ENT,
908                                           sizeof(*entry), flags, pc);
909         if (!event)
910                 return;
911         entry   = ring_buffer_event_data(event);
912         entry->graph_ent                        = *trace;
913         ring_buffer_unlock_commit(global_trace.buffer, event);
914 }
915
916 static void __trace_graph_return(struct trace_array *tr,
917                                 struct ftrace_graph_ret *trace,
918                                 unsigned long flags,
919                                 int pc)
920 {
921         struct ring_buffer_event *event;
922         struct ftrace_graph_ret_entry *entry;
923
924         if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled))))
925                 return;
926
927         event = trace_buffer_lock_reserve(&global_trace, TRACE_GRAPH_RET,
928                                           sizeof(*entry), flags, pc);
929         if (!event)
930                 return;
931         entry   = ring_buffer_event_data(event);
932         entry->ret                              = *trace;
933         ring_buffer_unlock_commit(global_trace.buffer, event);
934 }
935 #endif
936
937 void
938 ftrace(struct trace_array *tr, struct trace_array_cpu *data,
939        unsigned long ip, unsigned long parent_ip, unsigned long flags,
940        int pc)
941 {
942         if (likely(!atomic_read(&data->disabled)))
943                 trace_function(tr, ip, parent_ip, flags, pc);
944 }
945
946 static void __ftrace_trace_stack(struct trace_array *tr,
947                                  unsigned long flags,
948                                  int skip, int pc)
949 {
950 #ifdef CONFIG_STACKTRACE
951         struct ring_buffer_event *event;
952         struct stack_entry *entry;
953         struct stack_trace trace;
954
955         event = trace_buffer_lock_reserve(tr, TRACE_STACK,
956                                           sizeof(*entry), flags, pc);
957         if (!event)
958                 return;
959         entry   = ring_buffer_event_data(event);
960         memset(&entry->caller, 0, sizeof(entry->caller));
961
962         trace.nr_entries        = 0;
963         trace.max_entries       = FTRACE_STACK_ENTRIES;
964         trace.skip              = skip;
965         trace.entries           = entry->caller;
966
967         save_stack_trace(&trace);
968         ring_buffer_unlock_commit(tr->buffer, event);
969 #endif
970 }
971
972 static void ftrace_trace_stack(struct trace_array *tr,
973                                unsigned long flags,
974                                int skip, int pc)
975 {
976         if (!(trace_flags & TRACE_ITER_STACKTRACE))
977                 return;
978
979         __ftrace_trace_stack(tr, flags, skip, pc);
980 }
981
982 void __trace_stack(struct trace_array *tr,
983                    unsigned long flags,
984                    int skip, int pc)
985 {
986         __ftrace_trace_stack(tr, flags, skip, pc);
987 }
988
989 static void ftrace_trace_userstack(struct trace_array *tr,
990                                    unsigned long flags, int pc)
991 {
992 #ifdef CONFIG_STACKTRACE
993         struct ring_buffer_event *event;
994         struct userstack_entry *entry;
995         struct stack_trace trace;
996
997         if (!(trace_flags & TRACE_ITER_USERSTACKTRACE))
998                 return;
999
1000         event = trace_buffer_lock_reserve(tr, TRACE_USER_STACK,
1001                                           sizeof(*entry), flags, pc);
1002         if (!event)
1003                 return;
1004         entry   = ring_buffer_event_data(event);
1005
1006         memset(&entry->caller, 0, sizeof(entry->caller));
1007
1008         trace.nr_entries        = 0;
1009         trace.max_entries       = FTRACE_STACK_ENTRIES;
1010         trace.skip              = 0;
1011         trace.entries           = entry->caller;
1012
1013         save_stack_trace_user(&trace);
1014         ring_buffer_unlock_commit(tr->buffer, event);
1015 #endif
1016 }
1017
1018 #ifdef UNUSED
1019 static void __trace_userstack(struct trace_array *tr, unsigned long flags)
1020 {
1021         ftrace_trace_userstack(tr, flags, preempt_count());
1022 }
1023 #endif /* UNUSED */
1024
1025 static void
1026 ftrace_trace_special(void *__tr,
1027                      unsigned long arg1, unsigned long arg2, unsigned long arg3,
1028                      int pc)
1029 {
1030         struct ring_buffer_event *event;
1031         struct trace_array *tr = __tr;
1032         struct special_entry *entry;
1033
1034         event = trace_buffer_lock_reserve(tr, TRACE_SPECIAL,
1035                                           sizeof(*entry), 0, pc);
1036         if (!event)
1037                 return;
1038         entry   = ring_buffer_event_data(event);
1039         entry->arg1                     = arg1;
1040         entry->arg2                     = arg2;
1041         entry->arg3                     = arg3;
1042         trace_buffer_unlock_commit(tr, event, 0, pc);
1043 }
1044
1045 void
1046 __trace_special(void *__tr, void *__data,
1047                 unsigned long arg1, unsigned long arg2, unsigned long arg3)
1048 {
1049         ftrace_trace_special(__tr, arg1, arg2, arg3, preempt_count());
1050 }
1051
1052 void
1053 tracing_sched_switch_trace(struct trace_array *tr,
1054                            struct task_struct *prev,
1055                            struct task_struct *next,
1056                            unsigned long flags, int pc)
1057 {
1058         struct ring_buffer_event *event;
1059         struct ctx_switch_entry *entry;
1060
1061         event = trace_buffer_lock_reserve(tr, TRACE_CTX,
1062                                           sizeof(*entry), flags, pc);
1063         if (!event)
1064                 return;
1065         entry   = ring_buffer_event_data(event);
1066         entry->prev_pid                 = prev->pid;
1067         entry->prev_prio                = prev->prio;
1068         entry->prev_state               = prev->state;
1069         entry->next_pid                 = next->pid;
1070         entry->next_prio                = next->prio;
1071         entry->next_state               = next->state;
1072         entry->next_cpu = task_cpu(next);
1073         trace_buffer_unlock_commit(tr, event, flags, pc);
1074 }
1075
1076 void
1077 tracing_sched_wakeup_trace(struct trace_array *tr,
1078                            struct task_struct *wakee,
1079                            struct task_struct *curr,
1080                            unsigned long flags, int pc)
1081 {
1082         struct ring_buffer_event *event;
1083         struct ctx_switch_entry *entry;
1084
1085         event = trace_buffer_lock_reserve(tr, TRACE_WAKE,
1086                                           sizeof(*entry), flags, pc);
1087         if (!event)
1088                 return;
1089         entry   = ring_buffer_event_data(event);
1090         entry->prev_pid                 = curr->pid;
1091         entry->prev_prio                = curr->prio;
1092         entry->prev_state               = curr->state;
1093         entry->next_pid                 = wakee->pid;
1094         entry->next_prio                = wakee->prio;
1095         entry->next_state               = wakee->state;
1096         entry->next_cpu                 = task_cpu(wakee);
1097
1098         ring_buffer_unlock_commit(tr->buffer, event);
1099         ftrace_trace_stack(tr, flags, 6, pc);
1100         ftrace_trace_userstack(tr, flags, pc);
1101 }
1102
1103 void
1104 ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3)
1105 {
1106         struct trace_array *tr = &global_trace;
1107         struct trace_array_cpu *data;
1108         unsigned long flags;
1109         int cpu;
1110         int pc;
1111
1112         if (tracing_disabled)
1113                 return;
1114
1115         pc = preempt_count();
1116         local_irq_save(flags);
1117         cpu = raw_smp_processor_id();
1118         data = tr->data[cpu];
1119
1120         if (likely(atomic_inc_return(&data->disabled) == 1))
1121                 ftrace_trace_special(tr, arg1, arg2, arg3, pc);
1122
1123         atomic_dec(&data->disabled);
1124         local_irq_restore(flags);
1125 }
1126
1127 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1128 int trace_graph_entry(struct ftrace_graph_ent *trace)
1129 {
1130         struct trace_array *tr = &global_trace;
1131         struct trace_array_cpu *data;
1132         unsigned long flags;
1133         long disabled;
1134         int cpu;
1135         int pc;
1136
1137         if (!ftrace_trace_task(current))
1138                 return 0;
1139
1140         if (!ftrace_graph_addr(trace->func))
1141                 return 0;
1142
1143         local_irq_save(flags);
1144         cpu = raw_smp_processor_id();
1145         data = tr->data[cpu];
1146         disabled = atomic_inc_return(&data->disabled);
1147         if (likely(disabled == 1)) {
1148                 pc = preempt_count();
1149                 __trace_graph_entry(tr, trace, flags, pc);
1150         }
1151         /* Only do the atomic if it is not already set */
1152         if (!test_tsk_trace_graph(current))
1153                 set_tsk_trace_graph(current);
1154         atomic_dec(&data->disabled);
1155         local_irq_restore(flags);
1156
1157         return 1;
1158 }
1159
1160 void trace_graph_return(struct ftrace_graph_ret *trace)
1161 {
1162         struct trace_array *tr = &global_trace;
1163         struct trace_array_cpu *data;
1164         unsigned long flags;
1165         long disabled;
1166         int cpu;
1167         int pc;
1168
1169         local_irq_save(flags);
1170         cpu = raw_smp_processor_id();
1171         data = tr->data[cpu];
1172         disabled = atomic_inc_return(&data->disabled);
1173         if (likely(disabled == 1)) {
1174                 pc = preempt_count();
1175                 __trace_graph_return(tr, trace, flags, pc);
1176         }
1177         if (!trace->depth)
1178                 clear_tsk_trace_graph(current);
1179         atomic_dec(&data->disabled);
1180         local_irq_restore(flags);
1181 }
1182 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
1183
1184
1185 /**
1186  * trace_vbprintk - write binary msg to tracing buffer
1187  *
1188  */
1189 int trace_vbprintk(unsigned long ip, int depth, const char *fmt, va_list args)
1190 {
1191         static raw_spinlock_t trace_buf_lock =
1192                 (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
1193         static u32 trace_buf[TRACE_BUF_SIZE];
1194
1195         struct ring_buffer_event *event;
1196         struct trace_array *tr = &global_trace;
1197         struct trace_array_cpu *data;
1198         struct bprint_entry *entry;
1199         unsigned long flags;
1200         int resched;
1201         int cpu, len = 0, size, pc;
1202
1203         if (unlikely(tracing_selftest_running || tracing_disabled))
1204                 return 0;
1205
1206         /* Don't pollute graph traces with trace_vprintk internals */
1207         pause_graph_tracing();
1208
1209         pc = preempt_count();
1210         resched = ftrace_preempt_disable();
1211         cpu = raw_smp_processor_id();
1212         data = tr->data[cpu];
1213
1214         if (unlikely(atomic_read(&data->disabled)))
1215                 goto out;
1216
1217         /* Lockdep uses trace_printk for lock tracing */
1218         local_irq_save(flags);
1219         __raw_spin_lock(&trace_buf_lock);
1220         len = vbin_printf(trace_buf, TRACE_BUF_SIZE, fmt, args);
1221
1222         if (len > TRACE_BUF_SIZE || len < 0)
1223                 goto out_unlock;
1224
1225         size = sizeof(*entry) + sizeof(u32) * len;
1226         event = trace_buffer_lock_reserve(tr, TRACE_BPRINT, size, flags, pc);
1227         if (!event)
1228                 goto out_unlock;
1229         entry = ring_buffer_event_data(event);
1230         entry->ip                       = ip;
1231         entry->depth                    = depth;
1232         entry->fmt                      = fmt;
1233
1234         memcpy(entry->buf, trace_buf, sizeof(u32) * len);
1235         ring_buffer_unlock_commit(tr->buffer, event);
1236
1237 out_unlock:
1238         __raw_spin_unlock(&trace_buf_lock);
1239         local_irq_restore(flags);
1240
1241 out:
1242         ftrace_preempt_enable(resched);
1243         unpause_graph_tracing();
1244
1245         return len;
1246 }
1247 EXPORT_SYMBOL_GPL(trace_vbprintk);
1248
1249 int trace_vprintk(unsigned long ip, int depth, const char *fmt, va_list args)
1250 {
1251         static raw_spinlock_t trace_buf_lock = __RAW_SPIN_LOCK_UNLOCKED;
1252         static char trace_buf[TRACE_BUF_SIZE];
1253
1254         struct ring_buffer_event *event;
1255         struct trace_array *tr = &global_trace;
1256         struct trace_array_cpu *data;
1257         int cpu, len = 0, size, pc;
1258         struct print_entry *entry;
1259         unsigned long irq_flags;
1260
1261         if (tracing_disabled || tracing_selftest_running)
1262                 return 0;
1263
1264         pc = preempt_count();
1265         preempt_disable_notrace();
1266         cpu = raw_smp_processor_id();
1267         data = tr->data[cpu];
1268
1269         if (unlikely(atomic_read(&data->disabled)))
1270                 goto out;
1271
1272         pause_graph_tracing();
1273         raw_local_irq_save(irq_flags);
1274         __raw_spin_lock(&trace_buf_lock);
1275         len = vsnprintf(trace_buf, TRACE_BUF_SIZE, fmt, args);
1276
1277         len = min(len, TRACE_BUF_SIZE-1);
1278         trace_buf[len] = 0;
1279
1280         size = sizeof(*entry) + len + 1;
1281         event = trace_buffer_lock_reserve(tr, TRACE_PRINT, size, irq_flags, pc);
1282         if (!event)
1283                 goto out_unlock;
1284         entry = ring_buffer_event_data(event);
1285         entry->ip                       = ip;
1286         entry->depth                    = depth;
1287
1288         memcpy(&entry->buf, trace_buf, len);
1289         entry->buf[len] = 0;
1290         ring_buffer_unlock_commit(tr->buffer, event);
1291
1292  out_unlock:
1293         __raw_spin_unlock(&trace_buf_lock);
1294         raw_local_irq_restore(irq_flags);
1295         unpause_graph_tracing();
1296  out:
1297         preempt_enable_notrace();
1298
1299         return len;
1300 }
1301 EXPORT_SYMBOL_GPL(trace_vprintk);
1302
1303 enum trace_file_type {
1304         TRACE_FILE_LAT_FMT      = 1,
1305         TRACE_FILE_ANNOTATE     = 2,
1306 };
1307
1308 static void trace_iterator_increment(struct trace_iterator *iter)
1309 {
1310         /* Don't allow ftrace to trace into the ring buffers */
1311         ftrace_disable_cpu();
1312
1313         iter->idx++;
1314         if (iter->buffer_iter[iter->cpu])
1315                 ring_buffer_read(iter->buffer_iter[iter->cpu], NULL);
1316
1317         ftrace_enable_cpu();
1318 }
1319
1320 static struct trace_entry *
1321 peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts)
1322 {
1323         struct ring_buffer_event *event;
1324         struct ring_buffer_iter *buf_iter = iter->buffer_iter[cpu];
1325
1326         /* Don't allow ftrace to trace into the ring buffers */
1327         ftrace_disable_cpu();
1328
1329         if (buf_iter)
1330                 event = ring_buffer_iter_peek(buf_iter, ts);
1331         else
1332                 event = ring_buffer_peek(iter->tr->buffer, cpu, ts);
1333
1334         ftrace_enable_cpu();
1335
1336         return event ? ring_buffer_event_data(event) : NULL;
1337 }
1338
1339 static struct trace_entry *
1340 __find_next_entry(struct trace_iterator *iter, int *ent_cpu, u64 *ent_ts)
1341 {
1342         struct ring_buffer *buffer = iter->tr->buffer;
1343         struct trace_entry *ent, *next = NULL;
1344         int cpu_file = iter->cpu_file;
1345         u64 next_ts = 0, ts;
1346         int next_cpu = -1;
1347         int cpu;
1348
1349         /*
1350          * If we are in a per_cpu trace file, don't bother by iterating over
1351          * all cpu and peek directly.
1352          */
1353         if (cpu_file > TRACE_PIPE_ALL_CPU) {
1354                 if (ring_buffer_empty_cpu(buffer, cpu_file))
1355                         return NULL;
1356                 ent = peek_next_entry(iter, cpu_file, ent_ts);
1357                 if (ent_cpu)
1358                         *ent_cpu = cpu_file;
1359
1360                 return ent;
1361         }
1362
1363         for_each_tracing_cpu(cpu) {
1364
1365                 if (ring_buffer_empty_cpu(buffer, cpu))
1366                         continue;
1367
1368                 ent = peek_next_entry(iter, cpu, &ts);
1369
1370                 /*
1371                  * Pick the entry with the smallest timestamp:
1372                  */
1373                 if (ent && (!next || ts < next_ts)) {
1374                         next = ent;
1375                         next_cpu = cpu;
1376                         next_ts = ts;
1377                 }
1378         }
1379
1380         if (ent_cpu)
1381                 *ent_cpu = next_cpu;
1382
1383         if (ent_ts)
1384                 *ent_ts = next_ts;
1385
1386         return next;
1387 }
1388
1389 /* Find the next real entry, without updating the iterator itself */
1390 struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
1391                                           int *ent_cpu, u64 *ent_ts)
1392 {
1393         return __find_next_entry(iter, ent_cpu, ent_ts);
1394 }
1395
1396 /* Find the next real entry, and increment the iterator to the next entry */
1397 static void *find_next_entry_inc(struct trace_iterator *iter)
1398 {
1399         iter->ent = __find_next_entry(iter, &iter->cpu, &iter->ts);
1400
1401         if (iter->ent)
1402                 trace_iterator_increment(iter);
1403
1404         return iter->ent ? iter : NULL;
1405 }
1406
1407 static void trace_consume(struct trace_iterator *iter)
1408 {
1409         /* Don't allow ftrace to trace into the ring buffers */
1410         ftrace_disable_cpu();
1411         ring_buffer_consume(iter->tr->buffer, iter->cpu, &iter->ts);
1412         ftrace_enable_cpu();
1413 }
1414
1415 static void *s_next(struct seq_file *m, void *v, loff_t *pos)
1416 {
1417         struct trace_iterator *iter = m->private;
1418         int i = (int)*pos;
1419         void *ent;
1420
1421         (*pos)++;
1422
1423         /* can't go backwards */
1424         if (iter->idx > i)
1425                 return NULL;
1426
1427         if (iter->idx < 0)
1428                 ent = find_next_entry_inc(iter);
1429         else
1430                 ent = iter;
1431
1432         while (ent && iter->idx < i)
1433                 ent = find_next_entry_inc(iter);
1434
1435         iter->pos = *pos;
1436
1437         return ent;
1438 }
1439
1440 /*
1441  * No necessary locking here. The worst thing which can
1442  * happen is loosing events consumed at the same time
1443  * by a trace_pipe reader.
1444  * Other than that, we don't risk to crash the ring buffer
1445  * because it serializes the readers.
1446  *
1447  * The current tracer is copied to avoid a global locking
1448  * all around.
1449  */
1450 static void *s_start(struct seq_file *m, loff_t *pos)
1451 {
1452         struct trace_iterator *iter = m->private;
1453         static struct tracer *old_tracer;
1454         int cpu_file = iter->cpu_file;
1455         void *p = NULL;
1456         loff_t l = 0;
1457         int cpu;
1458
1459         /* copy the tracer to avoid using a global lock all around */
1460         mutex_lock(&trace_types_lock);
1461         if (unlikely(old_tracer != current_trace && current_trace)) {
1462                 old_tracer = current_trace;
1463                 *iter->trace = *current_trace;
1464         }
1465         mutex_unlock(&trace_types_lock);
1466
1467         atomic_inc(&trace_record_cmdline_disabled);
1468
1469         if (*pos != iter->pos) {
1470                 iter->ent = NULL;
1471                 iter->cpu = 0;
1472                 iter->idx = -1;
1473
1474                 ftrace_disable_cpu();
1475
1476                 if (cpu_file == TRACE_PIPE_ALL_CPU) {
1477                         for_each_tracing_cpu(cpu)
1478                                 ring_buffer_iter_reset(iter->buffer_iter[cpu]);
1479                 } else
1480                         ring_buffer_iter_reset(iter->buffer_iter[cpu_file]);
1481
1482
1483                 ftrace_enable_cpu();
1484
1485                 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
1486                         ;
1487
1488         } else {
1489                 l = *pos - 1;
1490                 p = s_next(m, p, &l);
1491         }
1492
1493         return p;
1494 }
1495
1496 static void s_stop(struct seq_file *m, void *p)
1497 {
1498         atomic_dec(&trace_record_cmdline_disabled);
1499 }
1500
1501 static void print_lat_help_header(struct seq_file *m)
1502 {
1503         seq_puts(m, "#                  _------=> CPU#            \n");
1504         seq_puts(m, "#                 / _-----=> irqs-off        \n");
1505         seq_puts(m, "#                | / _----=> need-resched    \n");
1506         seq_puts(m, "#                || / _---=> hardirq/softirq \n");
1507         seq_puts(m, "#                ||| / _--=> preempt-depth   \n");
1508         seq_puts(m, "#                |||| /                      \n");
1509         seq_puts(m, "#                |||||     delay             \n");
1510         seq_puts(m, "#  cmd     pid   ||||| time  |   caller      \n");
1511         seq_puts(m, "#     \\   /      |||||   \\   |   /           \n");
1512 }
1513
1514 static void print_func_help_header(struct seq_file *m)
1515 {
1516         seq_puts(m, "#           TASK-PID    CPU#    TIMESTAMP  FUNCTION\n");
1517         seq_puts(m, "#              | |       |          |         |\n");
1518 }
1519
1520
1521 static void
1522 print_trace_header(struct seq_file *m, struct trace_iterator *iter)
1523 {
1524         unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1525         struct trace_array *tr = iter->tr;
1526         struct trace_array_cpu *data = tr->data[tr->cpu];
1527         struct tracer *type = current_trace;
1528         unsigned long total;
1529         unsigned long entries;
1530         const char *name = "preemption";
1531
1532         if (type)
1533                 name = type->name;
1534
1535         entries = ring_buffer_entries(iter->tr->buffer);
1536         total = entries +
1537                 ring_buffer_overruns(iter->tr->buffer);
1538
1539         seq_printf(m, "# %s latency trace v1.1.5 on %s\n",
1540                    name, UTS_RELEASE);
1541         seq_puts(m, "# -----------------------------------"
1542                  "---------------------------------\n");
1543         seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d |"
1544                    " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
1545                    nsecs_to_usecs(data->saved_latency),
1546                    entries,
1547                    total,
1548                    tr->cpu,
1549 #if defined(CONFIG_PREEMPT_NONE)
1550                    "server",
1551 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
1552                    "desktop",
1553 #elif defined(CONFIG_PREEMPT)
1554                    "preempt",
1555 #else
1556                    "unknown",
1557 #endif
1558                    /* These are reserved for later use */
1559                    0, 0, 0, 0);
1560 #ifdef CONFIG_SMP
1561         seq_printf(m, " #P:%d)\n", num_online_cpus());
1562 #else
1563         seq_puts(m, ")\n");
1564 #endif
1565         seq_puts(m, "#    -----------------\n");
1566         seq_printf(m, "#    | task: %.16s-%d "
1567                    "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
1568                    data->comm, data->pid, data->uid, data->nice,
1569                    data->policy, data->rt_priority);
1570         seq_puts(m, "#    -----------------\n");
1571
1572         if (data->critical_start) {
1573                 seq_puts(m, "#  => started at: ");
1574                 seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
1575                 trace_print_seq(m, &iter->seq);
1576                 seq_puts(m, "\n#  => ended at:   ");
1577                 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
1578                 trace_print_seq(m, &iter->seq);
1579                 seq_puts(m, "#\n");
1580         }
1581
1582         seq_puts(m, "#\n");
1583 }
1584
1585 static void test_cpu_buff_start(struct trace_iterator *iter)
1586 {
1587         struct trace_seq *s = &iter->seq;
1588
1589         if (!(trace_flags & TRACE_ITER_ANNOTATE))
1590                 return;
1591
1592         if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
1593                 return;
1594
1595         if (cpumask_test_cpu(iter->cpu, iter->started))
1596                 return;
1597
1598         cpumask_set_cpu(iter->cpu, iter->started);
1599         trace_seq_printf(s, "##### CPU %u buffer started ####\n", iter->cpu);
1600 }
1601
1602 static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
1603 {
1604         struct trace_seq *s = &iter->seq;
1605         unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1606         struct trace_entry *entry;
1607         struct trace_event *event;
1608
1609         entry = iter->ent;
1610
1611         test_cpu_buff_start(iter);
1612
1613         event = ftrace_find_event(entry->type);
1614
1615         if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1616                 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
1617                         if (!trace_print_lat_context(iter))
1618                                 goto partial;
1619                 } else {
1620                         if (!trace_print_context(iter))
1621                                 goto partial;
1622                 }
1623         }
1624
1625         if (event)
1626                 return event->trace(iter, sym_flags);
1627
1628         if (!trace_seq_printf(s, "Unknown type %d\n", entry->type))
1629                 goto partial;
1630
1631         return TRACE_TYPE_HANDLED;
1632 partial:
1633         return TRACE_TYPE_PARTIAL_LINE;
1634 }
1635
1636 static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
1637 {
1638         struct trace_seq *s = &iter->seq;
1639         struct trace_entry *entry;
1640         struct trace_event *event;
1641
1642         entry = iter->ent;
1643
1644         if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1645                 if (!trace_seq_printf(s, "%d %d %llu ",
1646                                       entry->pid, iter->cpu, iter->ts))
1647                         goto partial;
1648         }
1649
1650         event = ftrace_find_event(entry->type);
1651         if (event)
1652                 return event->raw(iter, 0);
1653
1654         if (!trace_seq_printf(s, "%d ?\n", entry->type))
1655                 goto partial;
1656
1657         return TRACE_TYPE_HANDLED;
1658 partial:
1659         return TRACE_TYPE_PARTIAL_LINE;
1660 }
1661
1662 static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
1663 {
1664         struct trace_seq *s = &iter->seq;
1665         unsigned char newline = '\n';
1666         struct trace_entry *entry;
1667         struct trace_event *event;
1668
1669         entry = iter->ent;
1670
1671         if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1672                 SEQ_PUT_HEX_FIELD_RET(s, entry->pid);
1673                 SEQ_PUT_HEX_FIELD_RET(s, iter->cpu);
1674                 SEQ_PUT_HEX_FIELD_RET(s, iter->ts);
1675         }
1676
1677         event = ftrace_find_event(entry->type);
1678         if (event) {
1679                 enum print_line_t ret = event->hex(iter, 0);
1680                 if (ret != TRACE_TYPE_HANDLED)
1681                         return ret;
1682         }
1683
1684         SEQ_PUT_FIELD_RET(s, newline);
1685
1686         return TRACE_TYPE_HANDLED;
1687 }
1688
1689 static enum print_line_t print_bprintk_msg_only(struct trace_iterator *iter)
1690 {
1691         struct trace_seq *s = &iter->seq;
1692         struct trace_entry *entry = iter->ent;
1693         struct bprint_entry *field;
1694         int ret;
1695
1696         trace_assign_type(field, entry);
1697
1698         ret = trace_seq_bprintf(s, field->fmt, field->buf);
1699         if (!ret)
1700                 return TRACE_TYPE_PARTIAL_LINE;
1701
1702         return TRACE_TYPE_HANDLED;
1703 }
1704
1705 static enum print_line_t print_printk_msg_only(struct trace_iterator *iter)
1706 {
1707         struct trace_seq *s = &iter->seq;
1708         struct trace_entry *entry = iter->ent;
1709         struct print_entry *field;
1710         int ret;
1711
1712         trace_assign_type(field, entry);
1713
1714         ret = trace_seq_printf(s, "%s", field->buf);
1715         if (!ret)
1716                 return TRACE_TYPE_PARTIAL_LINE;
1717
1718         return TRACE_TYPE_HANDLED;
1719 }
1720
1721 static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
1722 {
1723         struct trace_seq *s = &iter->seq;
1724         struct trace_entry *entry;
1725         struct trace_event *event;
1726
1727         entry = iter->ent;
1728
1729         if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1730                 SEQ_PUT_FIELD_RET(s, entry->pid);
1731                 SEQ_PUT_FIELD_RET(s, iter->cpu);
1732                 SEQ_PUT_FIELD_RET(s, iter->ts);
1733         }
1734
1735         event = ftrace_find_event(entry->type);
1736         return event ? event->binary(iter, 0) : TRACE_TYPE_HANDLED;
1737 }
1738
1739 static int trace_empty(struct trace_iterator *iter)
1740 {
1741         int cpu;
1742
1743         /* If we are looking at one CPU buffer, only check that one */
1744         if (iter->cpu_file != TRACE_PIPE_ALL_CPU) {
1745                 cpu = iter->cpu_file;
1746                 if (iter->buffer_iter[cpu]) {
1747                         if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
1748                                 return 0;
1749                 } else {
1750                         if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu))
1751                                 return 0;
1752                 }
1753                 return 1;
1754         }
1755
1756         for_each_tracing_cpu(cpu) {
1757                 if (iter->buffer_iter[cpu]) {
1758                         if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
1759                                 return 0;
1760                 } else {
1761                         if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu))
1762                                 return 0;
1763                 }
1764         }
1765
1766         return 1;
1767 }
1768
1769 static enum print_line_t print_trace_line(struct trace_iterator *iter)
1770 {
1771         enum print_line_t ret;
1772
1773         if (iter->trace && iter->trace->print_line) {
1774                 ret = iter->trace->print_line(iter);
1775                 if (ret != TRACE_TYPE_UNHANDLED)
1776                         return ret;
1777         }
1778
1779         if (iter->ent->type == TRACE_BPRINT &&
1780                         trace_flags & TRACE_ITER_PRINTK &&
1781                         trace_flags & TRACE_ITER_PRINTK_MSGONLY)
1782                 return print_bprintk_msg_only(iter);
1783
1784         if (iter->ent->type == TRACE_PRINT &&
1785                         trace_flags & TRACE_ITER_PRINTK &&
1786                         trace_flags & TRACE_ITER_PRINTK_MSGONLY)
1787                 return print_printk_msg_only(iter);
1788
1789         if (trace_flags & TRACE_ITER_BIN)
1790                 return print_bin_fmt(iter);
1791
1792         if (trace_flags & TRACE_ITER_HEX)
1793                 return print_hex_fmt(iter);
1794
1795         if (trace_flags & TRACE_ITER_RAW)
1796                 return print_raw_fmt(iter);
1797
1798         return print_trace_fmt(iter);
1799 }
1800
1801 static int s_show(struct seq_file *m, void *v)
1802 {
1803         struct trace_iterator *iter = v;
1804
1805         if (iter->ent == NULL) {
1806                 if (iter->tr) {
1807                         seq_printf(m, "# tracer: %s\n", iter->trace->name);
1808                         seq_puts(m, "#\n");
1809                 }
1810                 if (iter->trace && iter->trace->print_header)
1811                         iter->trace->print_header(m);
1812                 else if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
1813                         /* print nothing if the buffers are empty */
1814                         if (trace_empty(iter))
1815                                 return 0;
1816                         print_trace_header(m, iter);
1817                         if (!(trace_flags & TRACE_ITER_VERBOSE))
1818                                 print_lat_help_header(m);
1819                 } else {
1820                         if (!(trace_flags & TRACE_ITER_VERBOSE))
1821                                 print_func_help_header(m);
1822                 }
1823         } else {
1824                 print_trace_line(iter);
1825                 trace_print_seq(m, &iter->seq);
1826         }
1827
1828         return 0;
1829 }
1830
1831 static struct seq_operations tracer_seq_ops = {
1832         .start          = s_start,
1833         .next           = s_next,
1834         .stop           = s_stop,
1835         .show           = s_show,
1836 };
1837
1838 static struct trace_iterator *
1839 __tracing_open(struct inode *inode, struct file *file)
1840 {
1841         long cpu_file = (long) inode->i_private;
1842         void *fail_ret = ERR_PTR(-ENOMEM);
1843         struct trace_iterator *iter;
1844         struct seq_file *m;
1845         int cpu, ret;
1846
1847         if (tracing_disabled)
1848                 return ERR_PTR(-ENODEV);
1849
1850         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
1851         if (!iter)
1852                 return ERR_PTR(-ENOMEM);
1853
1854         /*
1855          * We make a copy of the current tracer to avoid concurrent
1856          * changes on it while we are reading.
1857          */
1858         mutex_lock(&trace_types_lock);
1859         iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL);
1860         if (!iter->trace)
1861                 goto fail;
1862
1863         if (current_trace)
1864                 *iter->trace = *current_trace;
1865
1866         if (current_trace && current_trace->print_max)
1867                 iter->tr = &max_tr;
1868         else
1869                 iter->tr = &global_trace;
1870         iter->pos = -1;
1871         mutex_init(&iter->mutex);
1872         iter->cpu_file = cpu_file;
1873
1874         /* Notify the tracer early; before we stop tracing. */
1875         if (iter->trace && iter->trace->open)
1876                 iter->trace->open(iter);
1877
1878         /* Annotate start of buffers if we had overruns */
1879         if (ring_buffer_overruns(iter->tr->buffer))
1880                 iter->iter_flags |= TRACE_FILE_ANNOTATE;
1881
1882         if (iter->cpu_file == TRACE_PIPE_ALL_CPU) {
1883                 for_each_tracing_cpu(cpu) {
1884
1885                         iter->buffer_iter[cpu] =
1886                                 ring_buffer_read_start(iter->tr->buffer, cpu);
1887                 }
1888         } else {
1889                 cpu = iter->cpu_file;
1890                 iter->buffer_iter[cpu] =
1891                                 ring_buffer_read_start(iter->tr->buffer, cpu);
1892         }
1893
1894         /* TODO stop tracer */
1895         ret = seq_open(file, &tracer_seq_ops);
1896         if (ret < 0) {
1897                 fail_ret = ERR_PTR(ret);
1898                 goto fail_buffer;
1899         }
1900
1901         m = file->private_data;
1902         m->private = iter;
1903
1904         /* stop the trace while dumping */
1905         tracing_stop();
1906
1907         mutex_unlock(&trace_types_lock);
1908
1909         return iter;
1910
1911  fail_buffer:
1912         for_each_tracing_cpu(cpu) {
1913                 if (iter->buffer_iter[cpu])
1914                         ring_buffer_read_finish(iter->buffer_iter[cpu]);
1915         }
1916  fail:
1917         mutex_unlock(&trace_types_lock);
1918         kfree(iter->trace);
1919         kfree(iter);
1920
1921         return fail_ret;
1922 }
1923
1924 int tracing_open_generic(struct inode *inode, struct file *filp)
1925 {
1926         if (tracing_disabled)
1927                 return -ENODEV;
1928
1929         filp->private_data = inode->i_private;
1930         return 0;
1931 }
1932
1933 static int tracing_release(struct inode *inode, struct file *file)
1934 {
1935         struct seq_file *m = (struct seq_file *)file->private_data;
1936         struct trace_iterator *iter = m->private;
1937         int cpu;
1938
1939         mutex_lock(&trace_types_lock);
1940         for_each_tracing_cpu(cpu) {
1941                 if (iter->buffer_iter[cpu])
1942                         ring_buffer_read_finish(iter->buffer_iter[cpu]);
1943         }
1944
1945         if (iter->trace && iter->trace->close)
1946                 iter->trace->close(iter);
1947
1948         /* reenable tracing if it was previously enabled */
1949         tracing_start();
1950         mutex_unlock(&trace_types_lock);
1951
1952         seq_release(inode, file);
1953         mutex_destroy(&iter->mutex);
1954         kfree(iter->trace);
1955         kfree(iter);
1956         return 0;
1957 }
1958
1959 static int tracing_open(struct inode *inode, struct file *file)
1960 {
1961         struct trace_iterator *iter;
1962         int ret = 0;
1963
1964         iter = __tracing_open(inode, file);
1965         if (IS_ERR(iter))
1966                 ret = PTR_ERR(iter);
1967         else if (trace_flags & TRACE_ITER_LATENCY_FMT)
1968                 iter->iter_flags |= TRACE_FILE_LAT_FMT;
1969
1970         return ret;
1971 }
1972
1973 static void *
1974 t_next(struct seq_file *m, void *v, loff_t *pos)
1975 {
1976         struct tracer *t = m->private;
1977
1978         (*pos)++;
1979
1980         if (t)
1981                 t = t->next;
1982
1983         m->private = t;
1984
1985         return t;
1986 }
1987
1988 static void *t_start(struct seq_file *m, loff_t *pos)
1989 {
1990         struct tracer *t = m->private;
1991         loff_t l = 0;
1992
1993         mutex_lock(&trace_types_lock);
1994         for (; t && l < *pos; t = t_next(m, t, &l))
1995                 ;
1996
1997         return t;
1998 }
1999
2000 static void t_stop(struct seq_file *m, void *p)
2001 {
2002         mutex_unlock(&trace_types_lock);
2003 }
2004
2005 static int t_show(struct seq_file *m, void *v)
2006 {
2007         struct tracer *t = v;
2008
2009         if (!t)
2010                 return 0;
2011
2012         seq_printf(m, "%s", t->name);
2013         if (t->next)
2014                 seq_putc(m, ' ');
2015         else
2016                 seq_putc(m, '\n');
2017
2018         return 0;
2019 }
2020
2021 static struct seq_operations show_traces_seq_ops = {
2022         .start          = t_start,
2023         .next           = t_next,
2024         .stop           = t_stop,
2025         .show           = t_show,
2026 };
2027
2028 static int show_traces_open(struct inode *inode, struct file *file)
2029 {
2030         int ret;
2031
2032         if (tracing_disabled)
2033                 return -ENODEV;
2034
2035         ret = seq_open(file, &show_traces_seq_ops);
2036         if (!ret) {
2037                 struct seq_file *m = file->private_data;
2038                 m->private = trace_types;
2039         }
2040
2041         return ret;
2042 }
2043
2044 static const struct file_operations tracing_fops = {
2045         .open           = tracing_open,
2046         .read           = seq_read,
2047         .llseek         = seq_lseek,
2048         .release        = tracing_release,
2049 };
2050
2051 static const struct file_operations show_traces_fops = {
2052         .open           = show_traces_open,
2053         .read           = seq_read,
2054         .release        = seq_release,
2055 };
2056
2057 /*
2058  * Only trace on a CPU if the bitmask is set:
2059  */
2060 static cpumask_var_t tracing_cpumask;
2061
2062 /*
2063  * The tracer itself will not take this lock, but still we want
2064  * to provide a consistent cpumask to user-space:
2065  */
2066 static DEFINE_MUTEX(tracing_cpumask_update_lock);
2067
2068 /*
2069  * Temporary storage for the character representation of the
2070  * CPU bitmask (and one more byte for the newline):
2071  */
2072 static char mask_str[NR_CPUS + 1];
2073
2074 static ssize_t
2075 tracing_cpumask_read(struct file *filp, char __user *ubuf,
2076                      size_t count, loff_t *ppos)
2077 {
2078         int len;
2079
2080         mutex_lock(&tracing_cpumask_update_lock);
2081
2082         len = cpumask_scnprintf(mask_str, count, tracing_cpumask);
2083         if (count - len < 2) {
2084                 count = -EINVAL;
2085                 goto out_err;
2086         }
2087         len += sprintf(mask_str + len, "\n");
2088         count = simple_read_from_buffer(ubuf, count, ppos, mask_str, NR_CPUS+1);
2089
2090 out_err:
2091         mutex_unlock(&tracing_cpumask_update_lock);
2092
2093         return count;
2094 }
2095
2096 static ssize_t
2097 tracing_cpumask_write(struct file *filp, const char __user *ubuf,
2098                       size_t count, loff_t *ppos)
2099 {
2100         int err, cpu;
2101         cpumask_var_t tracing_cpumask_new;
2102
2103         if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
2104                 return -ENOMEM;
2105
2106         mutex_lock(&tracing_cpumask_update_lock);
2107         err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
2108         if (err)
2109                 goto err_unlock;
2110
2111         local_irq_disable();
2112         __raw_spin_lock(&ftrace_max_lock);
2113         for_each_tracing_cpu(cpu) {
2114                 /*
2115                  * Increase/decrease the disabled counter if we are
2116                  * about to flip a bit in the cpumask:
2117                  */
2118                 if (cpumask_test_cpu(cpu, tracing_cpumask) &&
2119                                 !cpumask_test_cpu(cpu, tracing_cpumask_new)) {
2120                         atomic_inc(&global_trace.data[cpu]->disabled);
2121                 }
2122                 if (!cpumask_test_cpu(cpu, tracing_cpumask) &&
2123                                 cpumask_test_cpu(cpu, tracing_cpumask_new)) {
2124                         atomic_dec(&global_trace.data[cpu]->disabled);
2125                 }
2126         }
2127         __raw_spin_unlock(&ftrace_max_lock);
2128         local_irq_enable();
2129
2130         cpumask_copy(tracing_cpumask, tracing_cpumask_new);
2131
2132         mutex_unlock(&tracing_cpumask_update_lock);
2133         free_cpumask_var(tracing_cpumask_new);
2134
2135         return count;
2136
2137 err_unlock:
2138         mutex_unlock(&tracing_cpumask_update_lock);
2139         free_cpumask_var(tracing_cpumask);
2140
2141         return err;
2142 }
2143
2144 static const struct file_operations tracing_cpumask_fops = {
2145         .open           = tracing_open_generic,
2146         .read           = tracing_cpumask_read,
2147         .write          = tracing_cpumask_write,
2148 };
2149
2150 static ssize_t
2151 tracing_trace_options_read(struct file *filp, char __user *ubuf,
2152                        size_t cnt, loff_t *ppos)
2153 {
2154         struct tracer_opt *trace_opts;
2155         u32 tracer_flags;
2156         int len = 0;
2157         char *buf;
2158         int r = 0;
2159         int i;
2160
2161
2162         /* calculate max size */
2163         for (i = 0; trace_options[i]; i++) {
2164                 len += strlen(trace_options[i]);
2165                 len += 3; /* "no" and newline */
2166         }
2167
2168         mutex_lock(&trace_types_lock);
2169         tracer_flags = current_trace->flags->val;
2170         trace_opts = current_trace->flags->opts;
2171
2172         /*
2173          * Increase the size with names of options specific
2174          * of the current tracer.
2175          */
2176         for (i = 0; trace_opts[i].name; i++) {
2177                 len += strlen(trace_opts[i].name);
2178                 len += 3; /* "no" and newline */
2179         }
2180
2181         /* +2 for \n and \0 */
2182         buf = kmalloc(len + 2, GFP_KERNEL);
2183         if (!buf) {
2184                 mutex_unlock(&trace_types_lock);
2185                 return -ENOMEM;
2186         }
2187
2188         for (i = 0; trace_options[i]; i++) {
2189                 if (trace_flags & (1 << i))
2190                         r += sprintf(buf + r, "%s\n", trace_options[i]);
2191                 else
2192                         r += sprintf(buf + r, "no%s\n", trace_options[i]);
2193         }
2194
2195         for (i = 0; trace_opts[i].name; i++) {
2196                 if (tracer_flags & trace_opts[i].bit)
2197                         r += sprintf(buf + r, "%s\n",
2198                                 trace_opts[i].name);
2199                 else
2200                         r += sprintf(buf + r, "no%s\n",
2201                                 trace_opts[i].name);
2202         }
2203         mutex_unlock(&trace_types_lock);
2204
2205         WARN_ON(r >= len + 2);
2206
2207         r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2208
2209         kfree(buf);
2210         return r;
2211 }
2212
2213 /* Try to assign a tracer specific option */
2214 static int set_tracer_option(struct tracer *trace, char *cmp, int neg)
2215 {
2216         struct tracer_flags *trace_flags = trace->flags;
2217         struct tracer_opt *opts = NULL;
2218         int ret = 0, i = 0;
2219         int len;
2220
2221         for (i = 0; trace_flags->opts[i].name; i++) {
2222                 opts = &trace_flags->opts[i];
2223                 len = strlen(opts->name);
2224
2225                 if (strncmp(cmp, opts->name, len) == 0) {
2226                         ret = trace->set_flag(trace_flags->val,
2227                                 opts->bit, !neg);
2228                         break;
2229                 }
2230         }
2231         /* Not found */
2232         if (!trace_flags->opts[i].name)
2233                 return -EINVAL;
2234
2235         /* Refused to handle */
2236         if (ret)
2237                 return ret;
2238
2239         if (neg)
2240                 trace_flags->val &= ~opts->bit;
2241         else
2242                 trace_flags->val |= opts->bit;
2243
2244         return 0;
2245 }
2246
2247 static ssize_t
2248 tracing_trace_options_write(struct file *filp, const char __user *ubuf,
2249                         size_t cnt, loff_t *ppos)
2250 {
2251         char buf[64];
2252         char *cmp = buf;
2253         int neg = 0;
2254         int ret;
2255         int i;
2256
2257         if (cnt >= sizeof(buf))
2258                 return -EINVAL;
2259
2260         if (copy_from_user(&buf, ubuf, cnt))
2261                 return -EFAULT;
2262
2263         buf[cnt] = 0;
2264
2265         if (strncmp(buf, "no", 2) == 0) {
2266                 neg = 1;
2267                 cmp += 2;
2268         }
2269
2270         for (i = 0; trace_options[i]; i++) {
2271                 int len = strlen(trace_options[i]);
2272
2273                 if (strncmp(cmp, trace_options[i], len) == 0) {
2274                         if (neg)
2275                                 trace_flags &= ~(1 << i);
2276                         else
2277                                 trace_flags |= (1 << i);
2278                         break;
2279                 }
2280         }
2281
2282         /* If no option could be set, test the specific tracer options */
2283         if (!trace_options[i]) {
2284                 mutex_lock(&trace_types_lock);
2285                 ret = set_tracer_option(current_trace, cmp, neg);
2286                 mutex_unlock(&trace_types_lock);
2287                 if (ret)
2288                         return ret;
2289         }
2290
2291         filp->f_pos += cnt;
2292
2293         return cnt;
2294 }
2295
2296 static const struct file_operations tracing_iter_fops = {
2297         .open           = tracing_open_generic,
2298         .read           = tracing_trace_options_read,
2299         .write          = tracing_trace_options_write,
2300 };
2301
2302 static const char readme_msg[] =
2303         "tracing mini-HOWTO:\n\n"
2304         "# mkdir /debug\n"
2305         "# mount -t debugfs nodev /debug\n\n"
2306         "# cat /debug/tracing/available_tracers\n"
2307         "wakeup preemptirqsoff preemptoff irqsoff ftrace sched_switch none\n\n"
2308         "# cat /debug/tracing/current_tracer\n"
2309         "none\n"
2310         "# echo sched_switch > /debug/tracing/current_tracer\n"
2311         "# cat /debug/tracing/current_tracer\n"
2312         "sched_switch\n"
2313         "# cat /debug/tracing/trace_options\n"
2314         "noprint-parent nosym-offset nosym-addr noverbose\n"
2315         "# echo print-parent > /debug/tracing/trace_options\n"
2316         "# echo 1 > /debug/tracing/tracing_enabled\n"
2317         "# cat /debug/tracing/trace > /tmp/trace.txt\n"
2318         "echo 0 > /debug/tracing/tracing_enabled\n"
2319 ;
2320
2321 static ssize_t
2322 tracing_readme_read(struct file *filp, char __user *ubuf,
2323                        size_t cnt, loff_t *ppos)
2324 {
2325         return simple_read_from_buffer(ubuf, cnt, ppos,
2326                                         readme_msg, strlen(readme_msg));
2327 }
2328
2329 static const struct file_operations tracing_readme_fops = {
2330         .open           = tracing_open_generic,
2331         .read           = tracing_readme_read,
2332 };
2333
2334 static ssize_t
2335 tracing_ctrl_read(struct file *filp, char __user *ubuf,
2336                   size_t cnt, loff_t *ppos)
2337 {
2338         char buf[64];
2339         int r;
2340
2341         r = sprintf(buf, "%u\n", tracer_enabled);
2342         return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2343 }
2344
2345 static ssize_t
2346 tracing_ctrl_write(struct file *filp, const char __user *ubuf,
2347                    size_t cnt, loff_t *ppos)
2348 {
2349         struct trace_array *tr = filp->private_data;
2350         char buf[64];
2351         unsigned long val;
2352         int ret;
2353
2354         if (cnt >= sizeof(buf))
2355                 return -EINVAL;
2356
2357         if (copy_from_user(&buf, ubuf, cnt))
2358                 return -EFAULT;
2359
2360         buf[cnt] = 0;
2361
2362         ret = strict_strtoul(buf, 10, &val);
2363         if (ret < 0)
2364                 return ret;
2365
2366         val = !!val;
2367
2368         mutex_lock(&trace_types_lock);
2369         if (tracer_enabled ^ val) {
2370                 if (val) {
2371                         tracer_enabled = 1;
2372                         if (current_trace->start)
2373                                 current_trace->start(tr);
2374                         tracing_start();
2375                 } else {
2376                         tracer_enabled = 0;
2377                         tracing_stop();
2378                         if (current_trace->stop)
2379                                 current_trace->stop(tr);
2380                 }
2381         }
2382         mutex_unlock(&trace_types_lock);
2383
2384         filp->f_pos += cnt;
2385
2386         return cnt;
2387 }
2388
2389 static ssize_t
2390 tracing_set_trace_read(struct file *filp, char __user *ubuf,
2391                        size_t cnt, loff_t *ppos)
2392 {
2393         char buf[max_tracer_type_len+2];
2394         int r;
2395
2396         mutex_lock(&trace_types_lock);
2397         if (current_trace)
2398                 r = sprintf(buf, "%s\n", current_trace->name);
2399         else
2400                 r = sprintf(buf, "\n");
2401         mutex_unlock(&trace_types_lock);
2402
2403         return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2404 }
2405
2406 int tracer_init(struct tracer *t, struct trace_array *tr)
2407 {
2408         tracing_reset_online_cpus(tr);
2409         return t->init(tr);
2410 }
2411
2412 static int tracing_resize_ring_buffer(unsigned long size)
2413 {
2414         int ret;
2415
2416         /*
2417          * If kernel or user changes the size of the ring buffer
2418          * we use the size that was given, and we can forget about
2419          * expanding it later.
2420          */
2421         ring_buffer_expanded = 1;
2422
2423         ret = ring_buffer_resize(global_trace.buffer, size);
2424         if (ret < 0)
2425                 return ret;
2426
2427         ret = ring_buffer_resize(max_tr.buffer, size);
2428         if (ret < 0) {
2429                 int r;
2430
2431                 r = ring_buffer_resize(global_trace.buffer,
2432                                        global_trace.entries);
2433                 if (r < 0) {
2434                         /*
2435                          * AARGH! We are left with different
2436                          * size max buffer!!!!
2437                          * The max buffer is our "snapshot" buffer.
2438                          * When a tracer needs a snapshot (one of the
2439                          * latency tracers), it swaps the max buffer
2440                          * with the saved snap shot. We succeeded to
2441                          * update the size of the main buffer, but failed to
2442                          * update the size of the max buffer. But when we tried
2443                          * to reset the main buffer to the original size, we
2444                          * failed there too. This is very unlikely to
2445                          * happen, but if it does, warn and kill all
2446                          * tracing.
2447                          */
2448                         WARN_ON(1);
2449                         tracing_disabled = 1;
2450                 }
2451                 return ret;
2452         }
2453
2454         global_trace.entries = size;
2455
2456         return ret;
2457 }
2458
2459 /**
2460  * tracing_update_buffers - used by tracing facility to expand ring buffers
2461  *
2462  * To save on memory when the tracing is never used on a system with it
2463  * configured in. The ring buffers are set to a minimum size. But once
2464  * a user starts to use the tracing facility, then they need to grow
2465  * to their default size.
2466  *
2467  * This function is to be called when a tracer is about to be used.
2468  */
2469 int tracing_update_buffers(void)
2470 {
2471         int ret = 0;
2472
2473         mutex_lock(&trace_types_lock);
2474         if (!ring_buffer_expanded)
2475                 ret = tracing_resize_ring_buffer(trace_buf_size);
2476         mutex_unlock(&trace_types_lock);
2477
2478         return ret;
2479 }
2480
2481 struct trace_option_dentry;
2482
2483 static struct trace_option_dentry *
2484 create_trace_option_files(struct tracer *tracer);
2485
2486 static void
2487 destroy_trace_option_files(struct trace_option_dentry *topts);
2488
2489 static int tracing_set_tracer(const char *buf)
2490 {
2491         static struct trace_option_dentry *topts;
2492         struct trace_array *tr = &global_trace;
2493         struct tracer *t;
2494         int ret = 0;
2495
2496         mutex_lock(&trace_types_lock);
2497
2498         if (!ring_buffer_expanded) {
2499                 ret = tracing_resize_ring_buffer(trace_buf_size);
2500                 if (ret < 0)
2501                         goto out;
2502                 ret = 0;
2503         }
2504
2505         for (t = trace_types; t; t = t->next) {
2506                 if (strcmp(t->name, buf) == 0)
2507                         break;
2508         }
2509         if (!t) {
2510                 ret = -EINVAL;
2511                 goto out;
2512         }
2513         if (t == current_trace)
2514                 goto out;
2515
2516         trace_branch_disable();
2517         if (current_trace && current_trace->reset)
2518                 current_trace->reset(tr);
2519
2520         destroy_trace_option_files(topts);
2521
2522         current_trace = t;
2523
2524         topts = create_trace_option_files(current_trace);
2525
2526         if (t->init) {
2527                 ret = tracer_init(t, tr);
2528                 if (ret)
2529                         goto out;
2530         }
2531
2532         trace_branch_enable(tr);
2533  out:
2534         mutex_unlock(&trace_types_lock);
2535
2536         return ret;
2537 }
2538
2539 static ssize_t
2540 tracing_set_trace_write(struct file *filp, const char __user *ubuf,
2541                         size_t cnt, loff_t *ppos)
2542 {
2543         char buf[max_tracer_type_len+1];
2544         int i;
2545         size_t ret;
2546         int err;
2547
2548         ret = cnt;
2549
2550         if (cnt > max_tracer_type_len)
2551                 cnt = max_tracer_type_len;
2552
2553         if (copy_from_user(&buf, ubuf, cnt))
2554                 return -EFAULT;
2555
2556         buf[cnt] = 0;
2557
2558         /* strip ending whitespace. */
2559         for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
2560                 buf[i] = 0;
2561
2562         err = tracing_set_tracer(buf);
2563         if (err)
2564                 return err;
2565
2566         filp->f_pos += ret;
2567
2568         return ret;
2569 }
2570
2571 static ssize_t
2572 tracing_max_lat_read(struct file *filp, char __user *ubuf,
2573                      size_t cnt, loff_t *ppos)
2574 {
2575         unsigned long *ptr = filp->private_data;
2576         char buf[64];
2577         int r;
2578
2579         r = snprintf(buf, sizeof(buf), "%ld\n",
2580                      *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
2581         if (r > sizeof(buf))
2582                 r = sizeof(buf);
2583         return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2584 }
2585
2586 static ssize_t
2587 tracing_max_lat_write(struct file *filp, const char __user *ubuf,
2588                       size_t cnt, loff_t *ppos)
2589 {
2590         unsigned long *ptr = filp->private_data;
2591         char buf[64];
2592         unsigned long val;
2593         int ret;
2594
2595         if (cnt >= sizeof(buf))
2596                 return -EINVAL;
2597
2598         if (copy_from_user(&buf, ubuf, cnt))
2599                 return -EFAULT;
2600
2601         buf[cnt] = 0;
2602
2603         ret = strict_strtoul(buf, 10, &val);
2604         if (ret < 0)
2605                 return ret;
2606
2607         *ptr = val * 1000;
2608
2609         return cnt;
2610 }
2611
2612 static int tracing_open_pipe(struct inode *inode, struct file *filp)
2613 {
2614         long cpu_file = (long) inode->i_private;
2615         struct trace_iterator *iter;
2616         int ret = 0;
2617
2618         if (tracing_disabled)
2619                 return -ENODEV;
2620
2621         mutex_lock(&trace_types_lock);
2622
2623         /* We only allow one reader per cpu */
2624         if (cpu_file == TRACE_PIPE_ALL_CPU) {
2625                 if (!cpumask_empty(tracing_reader_cpumask)) {
2626                         ret = -EBUSY;
2627                         goto out;
2628                 }
2629                 cpumask_setall(tracing_reader_cpumask);
2630         } else {
2631                 if (!cpumask_test_cpu(cpu_file, tracing_reader_cpumask))
2632                         cpumask_set_cpu(cpu_file, tracing_reader_cpumask);
2633                 else {
2634                         ret = -EBUSY;
2635                         goto out;
2636                 }
2637         }
2638
2639         /* create a buffer to store the information to pass to userspace */
2640         iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2641         if (!iter) {
2642                 ret = -ENOMEM;
2643                 goto out;
2644         }
2645
2646         /*
2647          * We make a copy of the current tracer to avoid concurrent
2648          * changes on it while we are reading.
2649          */
2650         iter->trace = kmalloc(sizeof(*iter->trace), GFP_KERNEL);
2651         if (!iter->trace) {
2652                 ret = -ENOMEM;
2653                 goto fail;
2654         }
2655         if (current_trace)
2656                 *iter->trace = *current_trace;
2657
2658         if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
2659                 ret = -ENOMEM;
2660                 goto fail;
2661         }
2662
2663         /* trace pipe does not show start of buffer */
2664         cpumask_setall(iter->started);
2665
2666         iter->cpu_file = cpu_file;
2667         iter->tr = &global_trace;
2668         mutex_init(&iter->mutex);
2669         filp->private_data = iter;
2670
2671         if (iter->trace->pipe_open)
2672                 iter->trace->pipe_open(iter);
2673
2674 out:
2675         mutex_unlock(&trace_types_lock);
2676         return ret;
2677
2678 fail:
2679         kfree(iter->trace);
2680         kfree(iter);
2681         mutex_unlock(&trace_types_lock);
2682         return ret;
2683 }
2684
2685 static int tracing_release_pipe(struct inode *inode, struct file *file)
2686 {
2687         struct trace_iterator *iter = file->private_data;
2688
2689         mutex_lock(&trace_types_lock);
2690
2691         if (iter->cpu_file == TRACE_PIPE_ALL_CPU)
2692                 cpumask_clear(tracing_reader_cpumask);
2693         else
2694                 cpumask_clear_cpu(iter->cpu_file, tracing_reader_cpumask);
2695
2696         mutex_unlock(&trace_types_lock);
2697
2698         free_cpumask_var(iter->started);
2699         mutex_destroy(&iter->mutex);
2700         kfree(iter->trace);
2701         kfree(iter);
2702
2703         return 0;
2704 }
2705
2706 static unsigned int
2707 tracing_poll_pipe(struct file *filp, poll_table *poll_table)
2708 {
2709         struct trace_iterator *iter = filp->private_data;
2710
2711         if (trace_flags & TRACE_ITER_BLOCK) {
2712                 /*
2713                  * Always select as readable when in blocking mode
2714                  */
2715                 return POLLIN | POLLRDNORM;
2716         } else {
2717                 if (!trace_empty(iter))
2718                         return POLLIN | POLLRDNORM;
2719                 poll_wait(filp, &trace_wait, poll_table);
2720                 if (!trace_empty(iter))
2721                         return POLLIN | POLLRDNORM;
2722
2723                 return 0;
2724         }
2725 }
2726
2727
2728 void default_wait_pipe(struct trace_iterator *iter)
2729 {
2730         DEFINE_WAIT(wait);
2731
2732         prepare_to_wait(&trace_wait, &wait, TASK_INTERRUPTIBLE);
2733
2734         if (trace_empty(iter))
2735                 schedule();
2736
2737         finish_wait(&trace_wait, &wait);
2738 }
2739
2740 /*
2741  * This is a make-shift waitqueue.
2742  * A tracer might use this callback on some rare cases:
2743  *
2744  *  1) the current tracer might hold the runqueue lock when it wakes up
2745  *     a reader, hence a deadlock (sched, function, and function graph tracers)
2746  *  2) the function tracers, trace all functions, we don't want
2747  *     the overhead of calling wake_up and friends
2748  *     (and tracing them too)
2749  *
2750  *     Anyway, this is really very primitive wakeup.
2751  */
2752 void poll_wait_pipe(struct trace_iterator *iter)
2753 {
2754         set_current_state(TASK_INTERRUPTIBLE);
2755         /* sleep for 100 msecs, and try again. */
2756         schedule_timeout(HZ / 10);
2757 }
2758
2759 /* Must be called with trace_types_lock mutex held. */
2760 static int tracing_wait_pipe(struct file *filp)
2761 {
2762         struct trace_iterator *iter = filp->private_data;
2763
2764         while (trace_empty(iter)) {
2765
2766                 if ((filp->f_flags & O_NONBLOCK)) {
2767                         return -EAGAIN;
2768                 }
2769
2770                 mutex_unlock(&iter->mutex);
2771
2772                 iter->trace->wait_pipe(iter);
2773
2774                 mutex_lock(&iter->mutex);
2775
2776                 if (signal_pending(current))
2777                         return -EINTR;
2778
2779                 /*
2780                  * We block until we read something and tracing is disabled.
2781                  * We still block if tracing is disabled, but we have never
2782                  * read anything. This allows a user to cat this file, and
2783                  * then enable tracing. But after we have read something,
2784                  * we give an EOF when tracing is again disabled.
2785                  *
2786                  * iter->pos will be 0 if we haven't read anything.
2787                  */
2788                 if (!tracer_enabled && iter->pos)
2789                         break;
2790         }
2791
2792         return 1;
2793 }
2794
2795 /*
2796  * Consumer reader.
2797  */
2798 static ssize_t
2799 tracing_read_pipe(struct file *filp, char __user *ubuf,
2800                   size_t cnt, loff_t *ppos)
2801 {
2802         struct trace_iterator *iter = filp->private_data;
2803         static struct tracer *old_tracer;
2804         ssize_t sret;
2805
2806         /* return any leftover data */
2807         sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
2808         if (sret != -EBUSY)
2809                 return sret;
2810
2811         trace_seq_init(&iter->seq);
2812
2813         /* copy the tracer to avoid using a global lock all around */
2814         mutex_lock(&trace_types_lock);
2815         if (unlikely(old_tracer != current_trace && current_trace)) {
2816                 old_tracer = current_trace;
2817                 *iter->trace = *current_trace;
2818         }
2819         mutex_unlock(&trace_types_lock);
2820
2821         /*
2822          * Avoid more than one consumer on a single file descriptor
2823          * This is just a matter of traces coherency, the ring buffer itself
2824          * is protected.
2825          */
2826         mutex_lock(&iter->mutex);
2827         if (iter->trace->read) {
2828                 sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
2829                 if (sret)
2830                         goto out;
2831         }
2832
2833 waitagain:
2834         sret = tracing_wait_pipe(filp);
2835         if (sret <= 0)
2836                 goto out;
2837
2838         /* stop when tracing is finished */
2839         if (trace_empty(iter)) {
2840                 sret = 0;
2841                 goto out;
2842         }
2843
2844         if (cnt >= PAGE_SIZE)
2845                 cnt = PAGE_SIZE - 1;
2846
2847         /* reset all but tr, trace, and overruns */
2848         memset(&iter->seq, 0,
2849                sizeof(struct trace_iterator) -
2850                offsetof(struct trace_iterator, seq));
2851         iter->pos = -1;
2852
2853         while (find_next_entry_inc(iter) != NULL) {
2854                 enum print_line_t ret;
2855                 int len = iter->seq.len;
2856
2857                 ret = print_trace_line(iter);
2858                 if (ret == TRACE_TYPE_PARTIAL_LINE) {
2859                         /* don't print partial lines */
2860                         iter->seq.len = len;
2861                         break;
2862                 }
2863                 if (ret != TRACE_TYPE_NO_CONSUME)
2864                         trace_consume(iter);
2865
2866                 if (iter->seq.len >= cnt)
2867                         break;
2868         }
2869
2870         /* Now copy what we have to the user */
2871         sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
2872         if (iter->seq.readpos >= iter->seq.len)
2873                 trace_seq_init(&iter->seq);
2874
2875         /*
2876          * If there was nothing to send to user, inspite of consuming trace
2877          * entries, go back to wait for more entries.
2878          */
2879         if (sret == -EBUSY)
2880                 goto waitagain;
2881
2882 out:
2883         mutex_unlock(&iter->mutex);
2884
2885         return sret;
2886 }
2887
2888 static void tracing_pipe_buf_release(struct pipe_inode_info *pipe,
2889                                      struct pipe_buffer *buf)
2890 {
2891         __free_page(buf->page);
2892 }
2893
2894 static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
2895                                      unsigned int idx)
2896 {
2897         __free_page(spd->pages[idx]);
2898 }
2899
2900 static struct pipe_buf_operations tracing_pipe_buf_ops = {
2901         .can_merge              = 0,
2902         .map                    = generic_pipe_buf_map,
2903         .unmap                  = generic_pipe_buf_unmap,
2904         .confirm                = generic_pipe_buf_confirm,
2905         .release                = tracing_pipe_buf_release,
2906         .steal                  = generic_pipe_buf_steal,
2907         .get                    = generic_pipe_buf_get,
2908 };
2909
2910 static size_t
2911 tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
2912 {
2913         size_t count;
2914         int ret;
2915
2916         /* Seq buffer is page-sized, exactly what we need. */
2917         for (;;) {
2918                 count = iter->seq.len;
2919                 ret = print_trace_line(iter);
2920                 count = iter->seq.len - count;
2921                 if (rem < count) {
2922                         rem = 0;
2923                         iter->seq.len -= count;
2924                         break;
2925                 }
2926                 if (ret == TRACE_TYPE_PARTIAL_LINE) {
2927                         iter->seq.len -= count;
2928                         break;
2929                 }
2930
2931                 trace_consume(iter);
2932                 rem -= count;
2933                 if (!find_next_entry_inc(iter)) {
2934                         rem = 0;
2935                         iter->ent = NULL;
2936                         break;
2937                 }
2938         }
2939
2940         return rem;
2941 }
2942
2943 static ssize_t tracing_splice_read_pipe(struct file *filp,
2944                                         loff_t *ppos,
2945                                         struct pipe_inode_info *pipe,
2946                                         size_t len,
2947                                         unsigned int flags)
2948 {
2949         struct page *pages[PIPE_BUFFERS];
2950         struct partial_page partial[PIPE_BUFFERS];
2951         struct trace_iterator *iter = filp->private_data;
2952         struct splice_pipe_desc spd = {
2953                 .pages          = pages,
2954                 .partial        = partial,
2955                 .nr_pages       = 0, /* This gets updated below. */
2956                 .flags          = flags,
2957                 .ops            = &tracing_pipe_buf_ops,
2958                 .spd_release    = tracing_spd_release_pipe,
2959         };
2960         static struct tracer *old_tracer;
2961         ssize_t ret;
2962         size_t rem;
2963         unsigned int i;
2964
2965         /* copy the tracer to avoid using a global lock all around */
2966         mutex_lock(&trace_types_lock);
2967         if (unlikely(old_tracer != current_trace && current_trace)) {
2968                 old_tracer = current_trace;
2969                 *iter->trace = *current_trace;
2970         }
2971         mutex_unlock(&trace_types_lock);
2972
2973         mutex_lock(&iter->mutex);
2974
2975         if (iter->trace->splice_read) {
2976                 ret = iter->trace->splice_read(iter, filp,
2977                                                ppos, pipe, len, flags);
2978                 if (ret)
2979                         goto out_err;
2980         }
2981
2982         ret = tracing_wait_pipe(filp);
2983         if (ret <= 0)
2984                 goto out_err;
2985
2986         if (!iter->ent && !find_next_entry_inc(iter)) {
2987                 ret = -EFAULT;
2988                 goto out_err;
2989         }
2990
2991         /* Fill as many pages as possible. */
2992         for (i = 0, rem = len; i < PIPE_BUFFERS && rem; i++) {
2993                 pages[i] = alloc_page(GFP_KERNEL);
2994                 if (!pages[i])
2995                         break;
2996
2997                 rem = tracing_fill_pipe_page(rem, iter);
2998
2999                 /* Copy the data into the page, so we can start over. */
3000                 ret = trace_seq_to_buffer(&iter->seq,
3001                                           page_address(pages[i]),
3002                                           iter->seq.len);
3003                 if (ret < 0) {
3004                         __free_page(pages[i]);
3005                         break;
3006                 }
3007                 partial[i].offset = 0;
3008                 partial[i].len = iter->seq.len;
3009
3010                 trace_seq_init(&iter->seq);
3011         }
3012
3013         mutex_unlock(&iter->mutex);
3014
3015         spd.nr_pages = i;
3016
3017         return splice_to_pipe(pipe, &spd);
3018
3019 out_err:
3020         mutex_unlock(&iter->mutex);
3021
3022         return ret;
3023 }
3024
3025 static ssize_t
3026 tracing_entries_read(struct file *filp, char __user *ubuf,
3027                      size_t cnt, loff_t *ppos)
3028 {
3029         struct trace_array *tr = filp->private_data;
3030         char buf[96];
3031         int r;
3032
3033         mutex_lock(&trace_types_lock);
3034         if (!ring_buffer_expanded)
3035                 r = sprintf(buf, "%lu (expanded: %lu)\n",
3036                             tr->entries >> 10,
3037                             trace_buf_size >> 10);
3038         else
3039                 r = sprintf(buf, "%lu\n", tr->entries >> 10);
3040         mutex_unlock(&trace_types_lock);
3041
3042         return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
3043 }
3044
3045 static ssize_t
3046 tracing_entries_write(struct file *filp, const char __user *ubuf,
3047                       size_t cnt, loff_t *ppos)
3048 {
3049         unsigned long val;
3050         char buf[64];
3051         int ret, cpu;
3052
3053         if (cnt >= sizeof(buf))
3054                 return -EINVAL;
3055
3056         if (copy_from_user(&buf, ubuf, cnt))
3057                 return -EFAULT;
3058
3059         buf[cnt] = 0;
3060
3061         ret = strict_strtoul(buf, 10, &val);
3062         if (ret < 0)
3063                 return ret;
3064
3065         /* must have at least 1 entry */
3066         if (!val)
3067                 return -EINVAL;
3068
3069         mutex_lock(&trace_types_lock);
3070
3071         tracing_stop();
3072
3073         /* disable all cpu buffers */
3074         for_each_tracing_cpu(cpu) {
3075                 if (global_trace.data[cpu])
3076                         atomic_inc(&global_trace.data[cpu]->disabled);
3077                 if (max_tr.data[cpu])
3078                         atomic_inc(&max_tr.data[cpu]->disabled);
3079         }
3080
3081         /* value is in KB */
3082         val <<= 10;
3083
3084         if (val != global_trace.entries) {
3085                 ret = tracing_resize_ring_buffer(val);
3086                 if (ret < 0) {
3087                         cnt = ret;
3088                         goto out;
3089                 }
3090         }
3091
3092         filp->f_pos += cnt;
3093
3094         /* If check pages failed, return ENOMEM */
3095         if (tracing_disabled)
3096                 cnt = -ENOMEM;
3097  out:
3098         for_each_tracing_cpu(cpu) {
3099                 if (global_trace.data[cpu])
3100                         atomic_dec(&global_trace.data[cpu]->disabled);
3101                 if (max_tr.data[cpu])
3102                         atomic_dec(&max_tr.data[cpu]->disabled);
3103         }
3104
3105         tracing_start();
3106         max_tr.entries = global_trace.entries;
3107         mutex_unlock(&trace_types_lock);
3108
3109         return cnt;
3110 }
3111
3112 static int mark_printk(const char *fmt, ...)
3113 {
3114         int ret;
3115         va_list args;
3116         va_start(args, fmt);
3117         ret = trace_vprintk(0, -1, fmt, args);
3118         va_end(args);
3119         return ret;
3120 }
3121
3122 static ssize_t
3123 tracing_mark_write(struct file *filp, const char __user *ubuf,
3124                                         size_t cnt, loff_t *fpos)
3125 {
3126         char *buf;
3127         char *end;
3128
3129         if (tracing_disabled)
3130                 return -EINVAL;
3131
3132         if (cnt > TRACE_BUF_SIZE)
3133                 cnt = TRACE_BUF_SIZE;
3134
3135         buf = kmalloc(cnt + 1, GFP_KERNEL);
3136         if (buf == NULL)
3137                 return -ENOMEM;
3138
3139         if (copy_from_user(buf, ubuf, cnt)) {
3140                 kfree(buf);
3141                 return -EFAULT;
3142         }
3143
3144         /* Cut from the first nil or newline. */
3145         buf[cnt] = '\0';
3146         end = strchr(buf, '\n');
3147         if (end)
3148                 *end = '\0';
3149
3150         cnt = mark_printk("%s\n", buf);
3151         kfree(buf);
3152         *fpos += cnt;
3153
3154         return cnt;
3155 }
3156
3157 static const struct file_operations tracing_max_lat_fops = {
3158         .open           = tracing_open_generic,
3159         .read           = tracing_max_lat_read,
3160         .write          = tracing_max_lat_write,
3161 };
3162
3163 static const struct file_operations tracing_ctrl_fops = {
3164         .open           = tracing_open_generic,
3165         .read           = tracing_ctrl_read,
3166         .write          = tracing_ctrl_write,
3167 };
3168
3169 static const struct file_operations set_tracer_fops = {
3170         .open           = tracing_open_generic,
3171         .read           = tracing_set_trace_read,
3172         .write          = tracing_set_trace_write,
3173 };
3174
3175 static const struct file_operations tracing_pipe_fops = {
3176         .open           = tracing_open_pipe,
3177         .poll           = tracing_poll_pipe,
3178         .read           = tracing_read_pipe,
3179         .splice_read    = tracing_splice_read_pipe,
3180         .release        = tracing_release_pipe,
3181 };
3182
3183 static const struct file_operations tracing_entries_fops = {
3184         .open           = tracing_open_generic,
3185         .read           = tracing_entries_read,
3186         .write          = tracing_entries_write,
3187 };
3188
3189 static const struct file_operations tracing_mark_fops = {
3190         .open           = tracing_open_generic,
3191         .write          = tracing_mark_write,
3192 };
3193
3194 struct ftrace_buffer_info {
3195         struct trace_array      *tr;
3196         void                    *spare;
3197         int                     cpu;
3198         unsigned int            read;
3199 };
3200
3201 static int tracing_buffers_open(struct inode *inode, struct file *filp)
3202 {
3203         int cpu = (int)(long)inode->i_private;
3204         struct ftrace_buffer_info *info;
3205
3206         if (tracing_disabled)
3207                 return -ENODEV;
3208
3209         info = kzalloc(sizeof(*info), GFP_KERNEL);
3210         if (!info)
3211                 return -ENOMEM;
3212
3213         info->tr        = &global_trace;
3214         info->cpu       = cpu;
3215         info->spare     = ring_buffer_alloc_read_page(info->tr->buffer);
3216         /* Force reading ring buffer for first read */
3217         info->read      = (unsigned int)-1;
3218         if (!info->spare)
3219                 goto out;
3220
3221         filp->private_data = info;
3222
3223         return 0;
3224
3225  out:
3226         kfree(info);
3227         return -ENOMEM;
3228 }
3229
3230 static ssize_t
3231 tracing_buffers_read(struct file *filp, char __user *ubuf,
3232                      size_t count, loff_t *ppos)
3233 {
3234         struct ftrace_buffer_info *info = filp->private_data;
3235         unsigned int pos;
3236         ssize_t ret;
3237         size_t size;
3238
3239         if (!count)
3240                 return 0;
3241
3242         /* Do we have previous read data to read? */
3243         if (info->read < PAGE_SIZE)
3244                 goto read;
3245
3246         info->read = 0;
3247
3248         ret = ring_buffer_read_page(info->tr->buffer,
3249                                     &info->spare,
3250                                     count,
3251                                     info->cpu, 0);
3252         if (ret < 0)
3253                 return 0;
3254
3255         pos = ring_buffer_page_len(info->spare);
3256
3257         if (pos < PAGE_SIZE)
3258                 memset(info->spare + pos, 0, PAGE_SIZE - pos);
3259
3260 read:
3261         size = PAGE_SIZE - info->read;
3262         if (size > count)
3263                 size = count;
3264
3265         ret = copy_to_user(ubuf, info->spare + info->read, size);
3266         if (ret == size)
3267                 return -EFAULT;
3268         size -= ret;
3269
3270         *ppos += size;
3271         info->read += size;
3272
3273         return size;
3274 }
3275
3276 static int tracing_buffers_release(struct inode *inode, struct file *file)
3277 {
3278         struct ftrace_buffer_info *info = file->private_data;
3279
3280         ring_buffer_free_read_page(info->tr->buffer, info->spare);
3281         kfree(info);
3282
3283         return 0;
3284 }
3285
3286 struct buffer_ref {
3287         struct ring_buffer      *buffer;
3288         void                    *page;
3289         int                     ref;
3290 };
3291
3292 static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
3293                                     struct pipe_buffer *buf)
3294 {
3295         struct buffer_ref *ref = (struct buffer_ref *)buf->private;
3296
3297         if (--ref->ref)
3298                 return;
3299
3300         ring_buffer_free_read_page(ref->buffer, ref->page);
3301         kfree(ref);
3302         buf->private = 0;
3303 }
3304
3305 static int buffer_pipe_buf_steal(struct pipe_inode_info *pipe,
3306                                  struct pipe_buffer *buf)
3307 {
3308         return 1;
3309 }
3310
3311 static void buffer_pipe_buf_get(struct pipe_inode_info *pipe,
3312                                 struct pipe_buffer *buf)
3313 {
3314         struct buffer_ref *ref = (struct buffer_ref *)buf->private;
3315
3316         ref->ref++;
3317 }
3318
3319 /* Pipe buffer operations for a buffer. */
3320 static struct pipe_buf_operations buffer_pipe_buf_ops = {
3321         .can_merge              = 0,
3322         .map                    = generic_pipe_buf_map,
3323         .unmap                  = generic_pipe_buf_unmap,
3324         .confirm                = generic_pipe_buf_confirm,
3325         .release                = buffer_pipe_buf_release,
3326         .steal                  = buffer_pipe_buf_steal,
3327         .get                    = buffer_pipe_buf_get,
3328 };
3329
3330 /*
3331  * Callback from splice_to_pipe(), if we need to release some pages
3332  * at the end of the spd in case we error'ed out in filling the pipe.
3333  */
3334 static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
3335 {
3336         struct buffer_ref *ref =
3337                 (struct buffer_ref *)spd->partial[i].private;
3338
3339         if (--ref->ref)
3340                 return;
3341
3342         ring_buffer_free_read_page(ref->buffer, ref->page);
3343         kfree(ref);
3344         spd->partial[i].private = 0;
3345 }
3346
3347 static ssize_t
3348 tracing_buffers_splice_read(struct file *file, loff_t *ppos,
3349                             struct pipe_inode_info *pipe, size_t len,
3350                             unsigned int flags)
3351 {
3352         struct ftrace_buffer_info *info = file->private_data;
3353         struct partial_page partial[PIPE_BUFFERS];
3354         struct page *pages[PIPE_BUFFERS];
3355         struct splice_pipe_desc spd = {
3356                 .pages          = pages,
3357                 .partial        = partial,
3358                 .flags          = flags,
3359                 .ops            = &buffer_pipe_buf_ops,
3360                 .spd_release    = buffer_spd_release,
3361         };
3362         struct buffer_ref *ref;
3363         int size, i;
3364         size_t ret;
3365
3366         /*
3367          * We can't seek on a buffer input
3368          */
3369         if (unlikely(*ppos))
3370                 return -ESPIPE;
3371
3372
3373         for (i = 0; i < PIPE_BUFFERS && len; i++, len -= size) {
3374                 struct page *page;
3375                 int r;
3376
3377                 ref = kzalloc(sizeof(*ref), GFP_KERNEL);
3378                 if (!ref)
3379                         break;
3380
3381                 ref->buffer = info->tr->buffer;
3382                 ref->page = ring_buffer_alloc_read_page(ref->buffer);
3383                 if (!ref->page) {
3384                         kfree(ref);
3385                         break;
3386                 }
3387
3388                 r = ring_buffer_read_page(ref->buffer, &ref->page,
3389                                           len, info->cpu, 0);
3390                 if (r < 0) {
3391                         ring_buffer_free_read_page(ref->buffer,
3392                                                    ref->page);
3393                         kfree(ref);
3394                         break;
3395                 }
3396
3397                 /*
3398                  * zero out any left over data, this is going to
3399                  * user land.
3400                  */
3401                 size = ring_buffer_page_len(ref->page);
3402                 if (size < PAGE_SIZE)
3403                         memset(ref->page + size, 0, PAGE_SIZE - size);
3404
3405                 page = virt_to_page(ref->page);
3406
3407                 spd.pages[i] = page;
3408                 spd.partial[i].len = PAGE_SIZE;
3409                 spd.partial[i].offset = 0;
3410                 spd.partial[i].private = (unsigned long)ref;
3411                 spd.nr_pages++;
3412         }
3413
3414         spd.nr_pages = i;
3415
3416         /* did we read anything? */
3417         if (!spd.nr_pages) {
3418                 if (flags & SPLICE_F_NONBLOCK)
3419                         ret = -EAGAIN;
3420                 else
3421                         ret = 0;
3422                 /* TODO: block */
3423                 return ret;
3424         }
3425
3426         ret = splice_to_pipe(pipe, &spd);
3427
3428         return ret;
3429 }
3430
3431 static const struct file_operations tracing_buffers_fops = {
3432         .open           = tracing_buffers_open,
3433         .read           = tracing_buffers_read,
3434         .release        = tracing_buffers_release,
3435         .splice_read    = tracing_buffers_splice_read,
3436         .llseek         = no_llseek,
3437 };
3438
3439 #ifdef CONFIG_DYNAMIC_FTRACE
3440
3441 int __weak ftrace_arch_read_dyn_info(char *buf, int size)
3442 {
3443         return 0;
3444 }
3445
3446 static ssize_t
3447 tracing_read_dyn_info(struct file *filp, char __user *ubuf,
3448                   size_t cnt, loff_t *ppos)
3449 {
3450         static char ftrace_dyn_info_buffer[1024];
3451         static DEFINE_MUTEX(dyn_info_mutex);
3452         unsigned long *p = filp->private_data;
3453         char *buf = ftrace_dyn_info_buffer;
3454         int size = ARRAY_SIZE(ftrace_dyn_info_buffer);
3455         int r;
3456
3457         mutex_lock(&dyn_info_mutex);
3458         r = sprintf(buf, "%ld ", *p);
3459
3460         r += ftrace_arch_read_dyn_info(buf+r, (size-1)-r);
3461         buf[r++] = '\n';
3462
3463         r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
3464
3465         mutex_unlock(&dyn_info_mutex);
3466
3467         return r;
3468 }
3469
3470 static const struct file_operations tracing_dyn_info_fops = {
3471         .open           = tracing_open_generic,
3472         .read           = tracing_read_dyn_info,
3473 };
3474 #endif
3475
3476 static struct dentry *d_tracer;
3477
3478 struct dentry *tracing_init_dentry(void)
3479 {
3480         static int once;
3481
3482         if (d_tracer)
3483                 return d_tracer;
3484
3485         d_tracer = debugfs_create_dir("tracing", NULL);
3486
3487         if (!d_tracer && !once) {
3488                 once = 1;
3489                 pr_warning("Could not create debugfs directory 'tracing'\n");
3490                 return NULL;
3491         }
3492
3493         return d_tracer;
3494 }
3495
3496 static struct dentry *d_percpu;
3497
3498 struct dentry *tracing_dentry_percpu(void)
3499 {
3500         static int once;
3501         struct dentry *d_tracer;
3502
3503         if (d_percpu)
3504                 return d_percpu;
3505
3506         d_tracer = tracing_init_dentry();
3507
3508         if (!d_tracer)
3509                 return NULL;
3510
3511         d_percpu = debugfs_create_dir("per_cpu", d_tracer);
3512
3513         if (!d_percpu && !once) {
3514                 once = 1;
3515                 pr_warning("Could not create debugfs directory 'per_cpu'\n");
3516                 return NULL;
3517         }
3518
3519         return d_percpu;
3520 }
3521
3522 static void tracing_init_debugfs_percpu(long cpu)
3523 {
3524         struct dentry *d_percpu = tracing_dentry_percpu();
3525         struct dentry *entry, *d_cpu;
3526         /* strlen(cpu) + MAX(log10(cpu)) + '\0' */
3527         char cpu_dir[7];
3528
3529         if (cpu > 999 || cpu < 0)
3530                 return;
3531
3532         sprintf(cpu_dir, "cpu%ld", cpu);
3533         d_cpu = debugfs_create_dir(cpu_dir, d_percpu);
3534         if (!d_cpu) {
3535                 pr_warning("Could not create debugfs '%s' entry\n", cpu_dir);
3536                 return;
3537         }
3538
3539         /* per cpu trace_pipe */
3540         entry = debugfs_create_file("trace_pipe", 0444, d_cpu,
3541                                 (void *)&nb