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