linux - kernel/trace/trace.c

4643 lines · 103.2 KiB

1	/*
2	* ring buffer based function tracer
3	*
4	* Copyright (C) 2007-2008 Steven Rostedt <[email protected]>
5	* Copyright (C) 2008 Ingo Molnar <[email protected]>
6	*
7	* Originally taken from the RT patch by:
8	* Arnaldo Carvalho de Melo <[email protected]>
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 <generated/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/rwsem.h>
35	#include <linux/slab.h>
36	#include <linux/ctype.h>
37	#include <linux/init.h>
38	#include <linux/poll.h>
39	#include <linux/fs.h>
40
41	#include "trace.h"
42	#include "trace_output.h"
43
44	#define TRACE_BUFFER_FLAGS (RB_FL_OVERWRITE)
45
46	/*
47	* On boot up, the ring buffer is set to the minimum size, so that
48	* we do not waste memory on systems that are not using tracing.
49	*/
50	int ring_buffer_expanded;
51
52	/*
53	* We need to change this state when a selftest is running.
54	* A selftest will lurk into the ring-buffer to count the
55	* entries inserted during the selftest although some concurrent
56	* insertions into the ring-buffer such as trace_printk could occurred
57	* at the same time, giving false positive or negative results.
58	*/
59	static bool __read_mostly tracing_selftest_running;
60
61	/*
62	* If a tracer is running, we do not want to run SELFTEST.
63	*/
64	bool __read_mostly tracing_selftest_disabled;
65
66	/* For tracers that don't implement custom flags */
67	static struct tracer_opt dummy_tracer_opt[] = {
68	{ }
69	};
70
71	static struct tracer_flags dummy_tracer_flags = {
72	.val = 0,
73	.opts = dummy_tracer_opt
74	};
75
76	static int dummy_set_flag(u32 old_flags, u32 bit, int set)
77	{
78	return 0;
79	}
80
81	/*
82	* Kill all tracing for good (never come back).
83	* It is initialized to 1 but will turn to zero if the initialization
84	* of the tracer is successful. But that is the only place that sets
85	* this back to zero.
86	*/
87	static int tracing_disabled = 1;
88
89	DEFINE_PER_CPU(int, ftrace_cpu_disabled);
90
91	static inline void ftrace_disable_cpu(void)
92	{
93	preempt_disable();
94	__this_cpu_inc(ftrace_cpu_disabled);
95	}
96
97	static inline void ftrace_enable_cpu(void)
98	{
99	__this_cpu_dec(ftrace_cpu_disabled);
100	preempt_enable();
101	}
102
103	cpumask_var_t __read_mostly tracing_buffer_mask;
104
105	/*
106	* ftrace_dump_on_oops - variable to dump ftrace buffer on oops
107	*
108	* If there is an oops (or kernel panic) and the ftrace_dump_on_oops
109	* is set, then ftrace_dump is called. This will output the contents
110	* of the ftrace buffers to the console. This is very useful for
111	* capturing traces that lead to crashes and outputing it to a
112	* serial console.
113	*
114	* It is default off, but you can enable it with either specifying
115	* "ftrace_dump_on_oops" in the kernel command line, or setting
116	* /proc/sys/kernel/ftrace_dump_on_oops
117	* Set 1 if you want to dump buffers of all CPUs
118	* Set 2 if you want to dump the buffer of the CPU that triggered oops
119	*/
120
121	enum ftrace_dump_mode ftrace_dump_on_oops;
122
123	static int tracing_set_tracer(const char *buf);
124
125	#define MAX_TRACER_SIZE 100
126	static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata;
127	static char *default_bootup_tracer;
128
129	static int __init set_cmdline_ftrace(char *str)
130	{
131	strncpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
132	default_bootup_tracer = bootup_tracer_buf;
133	/* We are using ftrace early, expand it */
134	ring_buffer_expanded = 1;
135	return 1;
136	}
137	__setup("ftrace=", set_cmdline_ftrace);
138
139	static int __init set_ftrace_dump_on_oops(char *str)
140	{
141	if (str++ != '=' \|\| !str) {
142	ftrace_dump_on_oops = DUMP_ALL;
143	return 1;
144	}
145
146	if (!strcmp("orig_cpu", str)) {
147	ftrace_dump_on_oops = DUMP_ORIG;
148	return 1;
149	}
150
151	return 0;
152	}
153	__setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
154
155	unsigned long long ns2usecs(cycle_t nsec)
156	{
157	nsec += 500;
158	do_div(nsec, 1000);
159	return nsec;
160	}
161
162	/*
163	* The global_trace is the descriptor that holds the tracing
164	* buffers for the live tracing. For each CPU, it contains
165	* a link list of pages that will store trace entries. The
166	* page descriptor of the pages in the memory is used to hold
167	* the link list by linking the lru item in the page descriptor
168	* to each of the pages in the buffer per CPU.
169	*
170	* For each active CPU there is a data field that holds the
171	* pages for the buffer for that CPU. Each CPU has the same number
172	* of pages allocated for its buffer.
173	*/
174	static struct trace_array global_trace;
175
176	static DEFINE_PER_CPU(struct trace_array_cpu, global_trace_cpu);
177
178	int filter_current_check_discard(struct ring_buffer *buffer,
179	struct ftrace_event_call call, void rec,
180	struct ring_buffer_event *event)
181	{
182	return filter_check_discard(call, rec, buffer, event);
183	}
184	EXPORT_SYMBOL_GPL(filter_current_check_discard);
185
186	cycle_t ftrace_now(int cpu)
187	{
188	u64 ts;
189
190	/* Early boot up does not have a buffer yet */
191	if (!global_trace.buffer)
192	return trace_clock_local();
193
194	ts = ring_buffer_time_stamp(global_trace.buffer, cpu);
195	ring_buffer_normalize_time_stamp(global_trace.buffer, cpu, &ts);
196
197	return ts;
198	}
199
200	/*
201	* The max_tr is used to snapshot the global_trace when a maximum
202	* latency is reached. Some tracers will use this to store a maximum
203	* trace while it continues examining live traces.
204	*
205	* The buffers for the max_tr are set up the same as the global_trace.
206	* When a snapshot is taken, the link list of the max_tr is swapped
207	* with the link list of the global_trace and the buffers are reset for
208	* the global_trace so the tracing can continue.
209	*/
210	static struct trace_array max_tr;
211
212	static DEFINE_PER_CPU(struct trace_array_cpu, max_tr_data);
213
214	/* tracer_enabled is used to toggle activation of a tracer */
215	static int tracer_enabled = 1;
216
217	/**
218	* tracing_is_enabled - return tracer_enabled status
219	*
220	* This function is used by other tracers to know the status
221	* of the tracer_enabled flag. Tracers may use this function
222	* to know if it should enable their features when starting
223	* up. See irqsoff tracer for an example (start_irqsoff_tracer).
224	*/
225	int tracing_is_enabled(void)
226	{
227	return tracer_enabled;
228	}
229
230	/*
231	* trace_buf_size is the size in bytes that is allocated
232	* for a buffer. Note, the number of bytes is always rounded
233	* to page size.
234	*
235	* This number is purposely set to a low number of 16384.
236	* If the dump on oops happens, it will be much appreciated
237	* to not have to wait for all that output. Anyway this can be
238	* boot time and run time configurable.
239	*/
240	#define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
241
242	static unsigned long trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
243
244	/* trace_types holds a link list of available tracers. */
245	static struct tracer *trace_types __read_mostly;
246
247	/* current_trace points to the tracer that is currently active */
248	static struct tracer *current_trace __read_mostly;
249
250	/*
251	* trace_types_lock is used to protect the trace_types list.
252	*/
253	static DEFINE_MUTEX(trace_types_lock);
254
255	/*
256	* serialize the access of the ring buffer
257	*
258	* ring buffer serializes readers, but it is low level protection.
259	* The validity of the events (which returns by ring_buffer_peek() ..etc)
260	* are not protected by ring buffer.
261	*
262	* The content of events may become garbage if we allow other process consumes
263	* these events concurrently:
264	* A) the page of the consumed events may become a normal page
265	* (not reader page) in ring buffer, and this page will be rewrited
266	* by events producer.
267	* B) The page of the consumed events may become a page for splice_read,
268	* and this page will be returned to system.
269	*
270	* These primitives allow multi process access to different cpu ring buffer
271	* concurrently.
272	*
273	* These primitives don't distinguish read-only and read-consume access.
274	* Multi read-only access are also serialized.
275	*/
276
277	#ifdef CONFIG_SMP
278	static DECLARE_RWSEM(all_cpu_access_lock);
279	static DEFINE_PER_CPU(struct mutex, cpu_access_lock);
280
281	static inline void trace_access_lock(int cpu)
282	{
283	if (cpu == TRACE_PIPE_ALL_CPU) {
284	/* gain it for accessing the whole ring buffer. */
285	down_write(&all_cpu_access_lock);
286	} else {
287	/* gain it for accessing a cpu ring buffer. */
288
289	/* Firstly block other trace_access_lock(TRACE_PIPE_ALL_CPU). */
290	down_read(&all_cpu_access_lock);
291
292	/* Secondly block other access to this @cpu ring buffer. */
293	mutex_lock(&per_cpu(cpu_access_lock, cpu));
294	}
295	}
296
297	static inline void trace_access_unlock(int cpu)
298	{
299	if (cpu == TRACE_PIPE_ALL_CPU) {
300	up_write(&all_cpu_access_lock);
301	} else {
302	mutex_unlock(&per_cpu(cpu_access_lock, cpu));
303	up_read(&all_cpu_access_lock);
304	}
305	}
306
307	static inline void trace_access_lock_init(void)
308	{
309	int cpu;
310
311	for_each_possible_cpu(cpu)
312	mutex_init(&per_cpu(cpu_access_lock, cpu));
313	}
314
315	#else
316
317	static DEFINE_MUTEX(access_lock);
318
319	static inline void trace_access_lock(int cpu)
320	{
321	(void)cpu;
322	mutex_lock(&access_lock);
323	}
324
325	static inline void trace_access_unlock(int cpu)
326	{
327	(void)cpu;
328	mutex_unlock(&access_lock);
329	}
330
331	static inline void trace_access_lock_init(void)
332	{
333	}
334
335	#endif
336
337	/* trace_wait is a waitqueue for tasks blocked on trace_poll */
338	static DECLARE_WAIT_QUEUE_HEAD(trace_wait);
339
340	/* trace_flags holds trace_options default values */
341	unsigned long trace_flags = TRACE_ITER_PRINT_PARENT \| TRACE_ITER_PRINTK \|
342	TRACE_ITER_ANNOTATE \| TRACE_ITER_CONTEXT_INFO \| TRACE_ITER_SLEEP_TIME \|
343	TRACE_ITER_GRAPH_TIME \| TRACE_ITER_RECORD_CMD;
344
345	static int trace_stop_count;
346	static DEFINE_SPINLOCK(tracing_start_lock);
347
348	/**
349	* trace_wake_up - wake up tasks waiting for trace input
350	*
351	* Simply wakes up any task that is blocked on the trace_wait
352	* queue. These is used with trace_poll for tasks polling the trace.
353	*/
354	void trace_wake_up(void)
355	{
356	int cpu;
357
358	if (trace_flags & TRACE_ITER_BLOCK)
359	return;
360	/*
361	* The runqueue_is_locked() can fail, but this is the best we
362	* have for now:
363	*/
364	cpu = get_cpu();
365	if (!runqueue_is_locked(cpu))
366	wake_up(&trace_wait);
367	put_cpu();
368	}
369
370	static int __init set_buf_size(char *str)
371	{
372	unsigned long buf_size;
373
374	if (!str)
375	return 0;
376	buf_size = memparse(str, &str);
377	/* nr_entries can not be zero */
378	if (buf_size == 0)
379	return 0;
380	trace_buf_size = buf_size;
381	return 1;
382	}
383	__setup("trace_buf_size=", set_buf_size);
384
385	static int __init set_tracing_thresh(char *str)
386	{
387	unsigned long threshhold;
388	int ret;
389
390	if (!str)
391	return 0;
392	ret = strict_strtoul(str, 0, &threshhold);
393	if (ret < 0)
394	return 0;
395	tracing_thresh = threshhold * 1000;
396	return 1;
397	}
398	__setup("tracing_thresh=", set_tracing_thresh);
399
400	unsigned long nsecs_to_usecs(unsigned long nsecs)
401	{
402	return nsecs / 1000;
403	}
404
405	/* These must match the bit postions in trace_iterator_flags */
406	static const char *trace_options[] = {
407	"print-parent",
408	"sym-offset",
409	"sym-addr",
410	"verbose",
411	"raw",
412	"hex",
413	"bin",
414	"block",
415	"stacktrace",
416	"trace_printk",
417	"ftrace_preempt",
418	"branch",
419	"annotate",
420	"userstacktrace",
421	"sym-userobj",
422	"printk-msg-only",
423	"context-info",
424	"latency-format",
425	"sleep-time",
426	"graph-time",
427	"record-cmd",
428	NULL
429	};
430
431	static struct {
432	u64 (*func)(void);
433	const char *name;
434	} trace_clocks[] = {
435	{ trace_clock_local, "local" },
436	{ trace_clock_global, "global" },
437	};
438
439	int trace_clock_id;
440
441	/*
442	* trace_parser_get_init - gets the buffer for trace parser
443	*/
444	int trace_parser_get_init(struct trace_parser *parser, int size)
445	{
446	memset(parser, 0, sizeof(*parser));
447
448	parser->buffer = kmalloc(size, GFP_KERNEL);
449	if (!parser->buffer)
450	return 1;
451
452	parser->size = size;
453	return 0;
454	}
455
456	/*
457	* trace_parser_put - frees the buffer for trace parser
458	*/
459	void trace_parser_put(struct trace_parser *parser)
460	{
461	kfree(parser->buffer);
462	}
463
464	/*
465	* trace_get_user - reads the user input string separated by space
466	* (matched by isspace(ch))
467	*
468	* For each string found the 'struct trace_parser' is updated,
469	* and the function returns.
470	*
471	* Returns number of bytes read.
472	*
473	* See kernel/trace/trace.h for 'struct trace_parser' details.
474	*/
475	int trace_get_user(struct trace_parser parser, const char __user ubuf,
476	size_t cnt, loff_t *ppos)
477	{
478	char ch;
479	size_t read = 0;
480	ssize_t ret;
481
482	if (!*ppos)
483	trace_parser_clear(parser);
484
485	ret = get_user(ch, ubuf++);
486	if (ret)
487	goto out;
488
489	read++;
490	cnt--;
491
492	/*
493	* The parser is not finished with the last write,
494	* continue reading the user input without skipping spaces.
495	*/
496	if (!parser->cont) {
497	/* skip white space */
498	while (cnt && isspace(ch)) {
499	ret = get_user(ch, ubuf++);
500	if (ret)
501	goto out;
502	read++;
503	cnt--;
504	}
505
506	/* only spaces were written */
507	if (isspace(ch)) {
508	*ppos += read;
509	ret = read;
510	goto out;
511	}
512
513	parser->idx = 0;
514	}
515
516	/* read the non-space input */
517	while (cnt && !isspace(ch)) {
518	if (parser->idx < parser->size - 1)
519	parser->buffer[parser->idx++] = ch;
520	else {
521	ret = -EINVAL;
522	goto out;
523	}
524	ret = get_user(ch, ubuf++);
525	if (ret)
526	goto out;
527	read++;
528	cnt--;
529	}
530
531	/* We either got finished input or we have to wait for another call. */
532	if (isspace(ch)) {
533	parser->buffer[parser->idx] = 0;
534	parser->cont = false;
535	} else {
536	parser->cont = true;
537	parser->buffer[parser->idx++] = ch;
538	}
539
540	*ppos += read;
541	ret = read;
542
543	out:
544	return ret;
545	}
546
547	ssize_t trace_seq_to_user(struct trace_seq s, char __user ubuf, size_t cnt)
548	{
549	int len;
550	int ret;
551
552	if (!cnt)
553	return 0;
554
555	if (s->len <= s->readpos)
556	return -EBUSY;
557
558	len = s->len - s->readpos;
559	if (cnt > len)
560	cnt = len;
561	ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
562	if (ret == cnt)
563	return -EFAULT;
564
565	cnt -= ret;
566
567	s->readpos += cnt;
568	return cnt;
569	}
570
571	static ssize_t trace_seq_to_buffer(struct trace_seq s, void buf, size_t cnt)
572	{
573	int len;
574	void *ret;
575
576	if (s->len <= s->readpos)
577	return -EBUSY;
578
579	len = s->len - s->readpos;
580	if (cnt > len)
581	cnt = len;
582	ret = memcpy(buf, s->buffer + s->readpos, cnt);
583	if (!ret)
584	return -EFAULT;
585
586	s->readpos += cnt;
587	return cnt;
588	}
589
590	/*
591	* ftrace_max_lock is used to protect the swapping of buffers
592	* when taking a max snapshot. The buffers themselves are
593	* protected by per_cpu spinlocks. But the action of the swap
594	* needs its own lock.
595	*
596	* This is defined as a arch_spinlock_t in order to help
597	* with performance when lockdep debugging is enabled.
598	*
599	* It is also used in other places outside the update_max_tr
600	* so it needs to be defined outside of the
601	* CONFIG_TRACER_MAX_TRACE.
602	*/
603	static arch_spinlock_t ftrace_max_lock =
604	(arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
605
606	unsigned long __read_mostly tracing_thresh;
607
608	#ifdef CONFIG_TRACER_MAX_TRACE
609	unsigned long __read_mostly tracing_max_latency;
610
611	/*
612	* Copy the new maximum trace into the separate maximum-trace
613	* structure. (this way the maximum trace is permanently saved,
614	* for later retrieval via /sys/kernel/debug/tracing/latency_trace)
615	*/
616	static void
617	__update_max_tr(struct trace_array tr, struct task_struct tsk, int cpu)
618	{
619	struct trace_array_cpu *data = tr->data[cpu];
620	struct trace_array_cpu *max_data;
621
622	max_tr.cpu = cpu;
623	max_tr.time_start = data->preempt_timestamp;
624
625	max_data = max_tr.data[cpu];
626	max_data->saved_latency = tracing_max_latency;
627	max_data->critical_start = data->critical_start;
628	max_data->critical_end = data->critical_end;
629
630	memcpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
631	max_data->pid = tsk->pid;
632	max_data->uid = task_uid(tsk);
633	max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
634	max_data->policy = tsk->policy;
635	max_data->rt_priority = tsk->rt_priority;
636
637	/* record this tasks comm */
638	tracing_record_cmdline(tsk);
639	}
640
641	/**
642	* update_max_tr - snapshot all trace buffers from global_trace to max_tr
643	* @tr: tracer
644	* @tsk: the task with the latency
645	* @cpu: The cpu that initiated the trace.
646	*
647	* Flip the buffers between the @tr and the max_tr and record information
648	* about which task was the cause of this latency.
649	*/
650	void
651	update_max_tr(struct trace_array tr, struct task_struct tsk, int cpu)
652	{
653	struct ring_buffer *buf = tr->buffer;
654
655	if (trace_stop_count)
656	return;
657
658	WARN_ON_ONCE(!irqs_disabled());
659	if (!current_trace->use_max_tr) {
660	WARN_ON_ONCE(1);
661	return;
662	}
663	arch_spin_lock(&ftrace_max_lock);
664
665	tr->buffer = max_tr.buffer;
666	max_tr.buffer = buf;
667
668	__update_max_tr(tr, tsk, cpu);
669	arch_spin_unlock(&ftrace_max_lock);
670	}
671
672	/**
673	* update_max_tr_single - only copy one trace over, and reset the rest
674	* @tr - tracer
675	* @tsk - task with the latency
676	* @cpu - the cpu of the buffer to copy.
677	*
678	* Flip the trace of a single CPU buffer between the @tr and the max_tr.
679	*/
680	void
681	update_max_tr_single(struct trace_array tr, struct task_struct tsk, int cpu)
682	{
683	int ret;
684
685	if (trace_stop_count)
686	return;
687
688	WARN_ON_ONCE(!irqs_disabled());
689	if (!current_trace->use_max_tr) {
690	WARN_ON_ONCE(1);
691	return;
692	}
693
694	arch_spin_lock(&ftrace_max_lock);
695
696	ftrace_disable_cpu();
697
698	ret = ring_buffer_swap_cpu(max_tr.buffer, tr->buffer, cpu);
699
700	if (ret == -EBUSY) {
701	/*
702	* We failed to swap the buffer due to a commit taking
703	* place on this CPU. We fail to record, but we reset
704	* the max trace buffer (no one writes directly to it)
705	* and flag that it failed.
706	*/
707	trace_array_printk(&max_tr, _THIS_IP_,
708	"Failed to swap buffers due to commit in progress\n");
709	}
710
711	ftrace_enable_cpu();
712
713	WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);
714
715	__update_max_tr(tr, tsk, cpu);
716	arch_spin_unlock(&ftrace_max_lock);
717	}
718	#endif /* CONFIG_TRACER_MAX_TRACE */
719
720	/**
721	* register_tracer - register a tracer with the ftrace system.
722	* @type - the plugin for the tracer
723	*
724	* Register a new plugin tracer.
725	*/
726	int register_tracer(struct tracer *type)
727	__releases(kernel_lock)
728	__acquires(kernel_lock)
729	{
730	struct tracer *t;
731	int ret = 0;
732
733	if (!type->name) {
734	pr_info("Tracer must have a name\n");
735	return -1;
736	}
737
738	if (strlen(type->name) >= MAX_TRACER_SIZE) {
739	pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE);
740	return -1;
741	}
742
743	mutex_lock(&trace_types_lock);
744
745	tracing_selftest_running = true;
746
747	for (t = trace_types; t; t = t->next) {
748	if (strcmp(type->name, t->name) == 0) {
749	/* already found */
750	pr_info("Tracer %s already registered\n",
751	type->name);
752	ret = -1;
753	goto out;
754	}
755	}
756
757	if (!type->set_flag)
758	type->set_flag = &dummy_set_flag;
759	if (!type->flags)
760	type->flags = &dummy_tracer_flags;
761	else
762	if (!type->flags->opts)
763	type->flags->opts = dummy_tracer_opt;
764	if (!type->wait_pipe)
765	type->wait_pipe = default_wait_pipe;
766
767
768	#ifdef CONFIG_FTRACE_STARTUP_TEST
769	if (type->selftest && !tracing_selftest_disabled) {
770	struct tracer *saved_tracer = current_trace;
771	struct trace_array *tr = &global_trace;
772
773	/*
774	* Run a selftest on this tracer.
775	* Here we reset the trace buffer, and set the current
776	* tracer to be this tracer. The tracer can then run some
777	* internal tracing to verify that everything is in order.
778	* If we fail, we do not register this tracer.
779	*/
780	tracing_reset_online_cpus(tr);
781
782	current_trace = type;
783	/* the test is responsible for initializing and enabling */
784	pr_info("Testing tracer %s: ", type->name);
785	ret = type->selftest(type, tr);
786	/* the test is responsible for resetting too */
787	current_trace = saved_tracer;
788	if (ret) {
789	printk(KERN_CONT "FAILED!\n");
790	goto out;
791	}
792	/* Only reset on passing, to avoid touching corrupted buffers */
793	tracing_reset_online_cpus(tr);
794
795	printk(KERN_CONT "PASSED\n");
796	}
797	#endif
798
799	type->next = trace_types;
800	trace_types = type;
801
802	out:
803	tracing_selftest_running = false;
804	mutex_unlock(&trace_types_lock);
805
806	if (ret \|\| !default_bootup_tracer)
807	goto out_unlock;
808
809	if (strncmp(default_bootup_tracer, type->name, MAX_TRACER_SIZE))
810	goto out_unlock;
811
812	printk(KERN_INFO "Starting tracer '%s'\n", type->name);
813	/* Do we want this tracer to start on bootup? */
814	tracing_set_tracer(type->name);
815	default_bootup_tracer = NULL;
816	/* disable other selftests, since this will break it. */
817	tracing_selftest_disabled = 1;
818	#ifdef CONFIG_FTRACE_STARTUP_TEST
819	printk(KERN_INFO "Disabling FTRACE selftests due to running tracer '%s'\n",
820	type->name);
821	#endif
822
823	out_unlock:
824	return ret;
825	}
826
827	void unregister_tracer(struct tracer *type)
828	{
829	struct tracer **t;
830
831	mutex_lock(&trace_types_lock);
832	for (t = &trace_types; t; t = &(t)->next) {
833	if (*t == type)
834	goto found;
835	}
836	pr_info("Tracer %s not registered\n", type->name);
837	goto out;
838
839	found:
840	t = (t)->next;
841
842	if (type == current_trace && tracer_enabled) {
843	tracer_enabled = 0;
844	tracing_stop();
845	if (current_trace->stop)
846	current_trace->stop(&global_trace);
847	current_trace = &nop_trace;
848	}
849	out:
850	mutex_unlock(&trace_types_lock);
851	}
852
853	static void __tracing_reset(struct ring_buffer *buffer, int cpu)
854	{
855	ftrace_disable_cpu();
856	ring_buffer_reset_cpu(buffer, cpu);
857	ftrace_enable_cpu();
858	}
859
860	void tracing_reset(struct trace_array *tr, int cpu)
861	{
862	struct ring_buffer *buffer = tr->buffer;
863
864	ring_buffer_record_disable(buffer);
865
866	/* Make sure all commits have finished */
867	synchronize_sched();
868	__tracing_reset(buffer, cpu);
869
870	ring_buffer_record_enable(buffer);
871	}
872
873	void tracing_reset_online_cpus(struct trace_array *tr)
874	{
875	struct ring_buffer *buffer = tr->buffer;
876	int cpu;
877
878	ring_buffer_record_disable(buffer);
879
880	/* Make sure all commits have finished */
881	synchronize_sched();
882
883	tr->time_start = ftrace_now(tr->cpu);
884
885	for_each_online_cpu(cpu)
886	__tracing_reset(buffer, cpu);
887
888	ring_buffer_record_enable(buffer);
889	}
890
891	void tracing_reset_current(int cpu)
892	{
893	tracing_reset(&global_trace, cpu);
894	}
895
896	void tracing_reset_current_online_cpus(void)
897	{
898	tracing_reset_online_cpus(&global_trace);
899	}
900
901	#define SAVED_CMDLINES 128
902	#define NO_CMDLINE_MAP UINT_MAX
903	static unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
904	static unsigned map_cmdline_to_pid[SAVED_CMDLINES];
905	static char saved_cmdlines[SAVED_CMDLINES][TASK_COMM_LEN];
906	static int cmdline_idx;
907	static arch_spinlock_t trace_cmdline_lock = __ARCH_SPIN_LOCK_UNLOCKED;
908
909	/* temporary disable recording */
910	static atomic_t trace_record_cmdline_disabled __read_mostly;
911
912	static void trace_init_cmdlines(void)
913	{
914	memset(&map_pid_to_cmdline, NO_CMDLINE_MAP, sizeof(map_pid_to_cmdline));
915	memset(&map_cmdline_to_pid, NO_CMDLINE_MAP, sizeof(map_cmdline_to_pid));
916	cmdline_idx = 0;
917	}
918
919	int is_tracing_stopped(void)
920	{
921	return trace_stop_count;
922	}
923
924	/**
925	* ftrace_off_permanent - disable all ftrace code permanently
926	*
927	* This should only be called when a serious anomally has
928	* been detected. This will turn off the function tracing,
929	* ring buffers, and other tracing utilites. It takes no
930	* locks and can be called from any context.
931	*/
932	void ftrace_off_permanent(void)
933	{
934	tracing_disabled = 1;
935	ftrace_stop();
936	tracing_off_permanent();
937	}
938
939	/**
940	* tracing_start - quick start of the tracer
941	*
942	* If tracing is enabled but was stopped by tracing_stop,
943	* this will start the tracer back up.
944	*/
945	void tracing_start(void)
946	{
947	struct ring_buffer *buffer;
948	unsigned long flags;
949
950	if (tracing_disabled)
951	return;
952
953	spin_lock_irqsave(&tracing_start_lock, flags);
954	if (--trace_stop_count) {
955	if (trace_stop_count < 0) {
956	/* Someone screwed up their debugging */
957	WARN_ON_ONCE(1);
958	trace_stop_count = 0;
959	}
960	goto out;
961	}
962
963	/* Prevent the buffers from switching */
964	arch_spin_lock(&ftrace_max_lock);
965
966	buffer = global_trace.buffer;
967	if (buffer)
968	ring_buffer_record_enable(buffer);
969
970	buffer = max_tr.buffer;
971	if (buffer)
972	ring_buffer_record_enable(buffer);
973
974	arch_spin_unlock(&ftrace_max_lock);
975
976	ftrace_start();
977	out:
978	spin_unlock_irqrestore(&tracing_start_lock, flags);
979	}
980
981	/**
982	* tracing_stop - quick stop of the tracer
983	*
984	* Light weight way to stop tracing. Use in conjunction with
985	* tracing_start.
986	*/
987	void tracing_stop(void)
988	{
989	struct ring_buffer *buffer;
990	unsigned long flags;
991
992	ftrace_stop();
993	spin_lock_irqsave(&tracing_start_lock, flags);
994	if (trace_stop_count++)
995	goto out;
996
997	/* Prevent the buffers from switching */
998	arch_spin_lock(&ftrace_max_lock);
999
1000	buffer = global_trace.buffer;
1001	if (buffer)
1002	ring_buffer_record_disable(buffer);
1003
1004	buffer = max_tr.buffer;
1005	if (buffer)
1006	ring_buffer_record_disable(buffer);
1007
1008	arch_spin_unlock(&ftrace_max_lock);
1009
1010	out:
1011	spin_unlock_irqrestore(&tracing_start_lock, flags);
1012	}
1013
1014	void trace_stop_cmdline_recording(void);
1015
1016	static void trace_save_cmdline(struct task_struct *tsk)
1017	{
1018	unsigned pid, idx;
1019
1020	if (!tsk->pid \|\| unlikely(tsk->pid > PID_MAX_DEFAULT))
1021	return;
1022
1023	/*
1024	* It's not the end of the world if we don't get
1025	* the lock, but we also don't want to spin
1026	* nor do we want to disable interrupts,
1027	* so if we miss here, then better luck next time.
1028	*/
1029	if (!arch_spin_trylock(&trace_cmdline_lock))
1030	return;
1031
1032	idx = map_pid_to_cmdline[tsk->pid];
1033	if (idx == NO_CMDLINE_MAP) {
1034	idx = (cmdline_idx + 1) % SAVED_CMDLINES;
1035
1036	/*
1037	* Check whether the cmdline buffer at idx has a pid
1038	* mapped. We are going to overwrite that entry so we
1039	* need to clear the map_pid_to_cmdline. Otherwise we
1040	* would read the new comm for the old pid.
1041	*/
1042	pid = map_cmdline_to_pid[idx];
1043	if (pid != NO_CMDLINE_MAP)
1044	map_pid_to_cmdline[pid] = NO_CMDLINE_MAP;
1045
1046	map_cmdline_to_pid[idx] = tsk->pid;
1047	map_pid_to_cmdline[tsk->pid] = idx;
1048
1049	cmdline_idx = idx;
1050	}
1051
1052	memcpy(&saved_cmdlines[idx], tsk->comm, TASK_COMM_LEN);
1053
1054	arch_spin_unlock(&trace_cmdline_lock);
1055	}
1056
1057	void trace_find_cmdline(int pid, char comm[])
1058	{
1059	unsigned map;
1060
1061	if (!pid) {
1062	strcpy(comm, "<idle>");
1063	return;
1064	}
1065
1066	if (WARN_ON_ONCE(pid < 0)) {
1067	strcpy(comm, "<XXX>");
1068	return;
1069	}
1070
1071	if (pid > PID_MAX_DEFAULT) {
1072	strcpy(comm, "<...>");
1073	return;
1074	}
1075
1076	preempt_disable();
1077	arch_spin_lock(&trace_cmdline_lock);
1078	map = map_pid_to_cmdline[pid];
1079	if (map != NO_CMDLINE_MAP)
1080	strcpy(comm, saved_cmdlines[map]);
1081	else
1082	strcpy(comm, "<...>");
1083
1084	arch_spin_unlock(&trace_cmdline_lock);
1085	preempt_enable();
1086	}
1087
1088	void tracing_record_cmdline(struct task_struct *tsk)
1089	{
1090	if (atomic_read(&trace_record_cmdline_disabled) \|\| !tracer_enabled \|\|
1091	!tracing_is_on())
1092	return;
1093
1094	trace_save_cmdline(tsk);
1095	}
1096
1097	void
1098	tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
1099	int pc)
1100	{
1101	struct task_struct *tsk = current;
1102
1103	entry->preempt_count = pc & 0xff;
1104	entry->pid = (tsk) ? tsk->pid : 0;
1105	entry->lock_depth = (tsk) ? tsk->lock_depth : 0;
1106	entry->flags =
1107	#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
1108	(irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) \|
1109	#else
1110	TRACE_FLAG_IRQS_NOSUPPORT \|
1111	#endif
1112	((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) \|
1113	((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) \|
1114	(need_resched() ? TRACE_FLAG_NEED_RESCHED : 0);
1115	}
1116	EXPORT_SYMBOL_GPL(tracing_generic_entry_update);
1117
1118	struct ring_buffer_event *
1119	trace_buffer_lock_reserve(struct ring_buffer *buffer,
1120	int type,
1121	unsigned long len,
1122	unsigned long flags, int pc)
1123	{
1124	struct ring_buffer_event *event;
1125
1126	event = ring_buffer_lock_reserve(buffer, len);
1127	if (event != NULL) {
1128	struct trace_entry *ent = ring_buffer_event_data(event);
1129
1130	tracing_generic_entry_update(ent, flags, pc);
1131	ent->type = type;
1132	}
1133
1134	return event;
1135	}
1136
1137	static inline void
1138	__trace_buffer_unlock_commit(struct ring_buffer *buffer,
1139	struct ring_buffer_event *event,
1140	unsigned long flags, int pc,
1141	int wake)
1142	{
1143	ring_buffer_unlock_commit(buffer, event);
1144
1145	ftrace_trace_stack(buffer, flags, 6, pc);
1146	ftrace_trace_userstack(buffer, flags, pc);
1147
1148	if (wake)
1149	trace_wake_up();
1150	}
1151
1152	void trace_buffer_unlock_commit(struct ring_buffer *buffer,
1153	struct ring_buffer_event *event,
1154	unsigned long flags, int pc)
1155	{
1156	__trace_buffer_unlock_commit(buffer, event, flags, pc, 1);
1157	}
1158
1159	struct ring_buffer_event *
1160	trace_current_buffer_lock_reserve(struct ring_buffer **current_rb,
1161	int type, unsigned long len,
1162	unsigned long flags, int pc)
1163	{
1164	*current_rb = global_trace.buffer;
1165	return trace_buffer_lock_reserve(*current_rb,
1166	type, len, flags, pc);
1167	}
1168	EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve);
1169
1170	void trace_current_buffer_unlock_commit(struct ring_buffer *buffer,
1171	struct ring_buffer_event *event,
1172	unsigned long flags, int pc)
1173	{
1174	__trace_buffer_unlock_commit(buffer, event, flags, pc, 1);
1175	}
1176	EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit);
1177
1178	void trace_nowake_buffer_unlock_commit(struct ring_buffer *buffer,
1179	struct ring_buffer_event *event,
1180	unsigned long flags, int pc)
1181	{
1182	__trace_buffer_unlock_commit(buffer, event, flags, pc, 0);
1183	}
1184	EXPORT_SYMBOL_GPL(trace_nowake_buffer_unlock_commit);
1185
1186	void trace_current_buffer_discard_commit(struct ring_buffer *buffer,
1187	struct ring_buffer_event *event)
1188	{
1189	ring_buffer_discard_commit(buffer, event);
1190	}
1191	EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit);
1192
1193	void
1194	trace_function(struct trace_array *tr,
1195	unsigned long ip, unsigned long parent_ip, unsigned long flags,
1196	int pc)
1197	{
1198	struct ftrace_event_call *call = &event_function;
1199	struct ring_buffer *buffer = tr->buffer;
1200	struct ring_buffer_event *event;
1201	struct ftrace_entry *entry;
1202
1203	/* If we are reading the ring buffer, don't trace */
1204	if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))
1205	return;
1206
1207	event = trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
1208	flags, pc);
1209	if (!event)
1210	return;
1211	entry = ring_buffer_event_data(event);
1212	entry->ip = ip;
1213	entry->parent_ip = parent_ip;
1214
1215	if (!filter_check_discard(call, entry, buffer, event))
1216	ring_buffer_unlock_commit(buffer, event);
1217	}
1218
1219	void
1220	ftrace(struct trace_array tr, struct trace_array_cpu data,
1221	unsigned long ip, unsigned long parent_ip, unsigned long flags,
1222	int pc)
1223	{
1224	if (likely(!atomic_read(&data->disabled)))
1225	trace_function(tr, ip, parent_ip, flags, pc);
1226	}
1227
1228	#ifdef CONFIG_STACKTRACE
1229	static void __ftrace_trace_stack(struct ring_buffer *buffer,
1230	unsigned long flags,
1231	int skip, int pc)
1232	{
1233	struct ftrace_event_call *call = &event_kernel_stack;
1234	struct ring_buffer_event *event;
1235	struct stack_entry *entry;
1236	struct stack_trace trace;
1237
1238	event = trace_buffer_lock_reserve(buffer, TRACE_STACK,
1239	sizeof(*entry), flags, pc);
1240	if (!event)
1241	return;
1242	entry = ring_buffer_event_data(event);
1243	memset(&entry->caller, 0, sizeof(entry->caller));
1244
1245	trace.nr_entries = 0;
1246	trace.max_entries = FTRACE_STACK_ENTRIES;
1247	trace.skip = skip;
1248	trace.entries = entry->caller;
1249
1250	save_stack_trace(&trace);
1251	if (!filter_check_discard(call, entry, buffer, event))
1252	ring_buffer_unlock_commit(buffer, event);
1253	}
1254
1255	void ftrace_trace_stack(struct ring_buffer *buffer, unsigned long flags,
1256	int skip, int pc)
1257	{
1258	if (!(trace_flags & TRACE_ITER_STACKTRACE))
1259	return;
1260
1261	__ftrace_trace_stack(buffer, flags, skip, pc);
1262	}
1263
1264	void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
1265	int pc)
1266	{
1267	__ftrace_trace_stack(tr->buffer, flags, skip, pc);
1268	}
1269
1270	/**
1271	* trace_dump_stack - record a stack back trace in the trace buffer
1272	*/
1273	void trace_dump_stack(void)
1274	{
1275	unsigned long flags;
1276
1277	if (tracing_disabled \|\| tracing_selftest_running)
1278	return;
1279
1280	local_save_flags(flags);
1281
1282	/* skipping 3 traces, seems to get us at the caller of this function */
1283	__ftrace_trace_stack(global_trace.buffer, flags, 3, preempt_count());
1284	}
1285
1286	static DEFINE_PER_CPU(int, user_stack_count);
1287
1288	void
1289	ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
1290	{
1291	struct ftrace_event_call *call = &event_user_stack;
1292	struct ring_buffer_event *event;
1293	struct userstack_entry *entry;
1294	struct stack_trace trace;
1295
1296	if (!(trace_flags & TRACE_ITER_USERSTACKTRACE))
1297	return;
1298
1299	/*
1300	* NMIs can not handle page faults, even with fix ups.
1301	* The save user stack can (and often does) fault.
1302	*/
1303	if (unlikely(in_nmi()))
1304	return;
1305
1306	/*
1307	* prevent recursion, since the user stack tracing may
1308	* trigger other kernel events.
1309	*/
1310	preempt_disable();
1311	if (__this_cpu_read(user_stack_count))
1312	goto out;
1313
1314	__this_cpu_inc(user_stack_count);
1315
1316	event = trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
1317	sizeof(*entry), flags, pc);
1318	if (!event)
1319	goto out_drop_count;
1320	entry = ring_buffer_event_data(event);
1321
1322	entry->tgid = current->tgid;
1323	memset(&entry->caller, 0, sizeof(entry->caller));
1324
1325	trace.nr_entries = 0;
1326	trace.max_entries = FTRACE_STACK_ENTRIES;
1327	trace.skip = 0;
1328	trace.entries = entry->caller;
1329
1330	save_stack_trace_user(&trace);
1331	if (!filter_check_discard(call, entry, buffer, event))
1332	ring_buffer_unlock_commit(buffer, event);
1333
1334	out_drop_count:
1335	__this_cpu_dec(user_stack_count);
1336	out:
1337	preempt_enable();
1338	}
1339
1340	#ifdef UNUSED
1341	static void __trace_userstack(struct trace_array *tr, unsigned long flags)
1342	{
1343	ftrace_trace_userstack(tr, flags, preempt_count());
1344	}
1345	#endif /* UNUSED */
1346
1347	#endif /* CONFIG_STACKTRACE */
1348
1349	/**
1350	* trace_vbprintk - write binary msg to tracing buffer
1351	*
1352	*/
1353	int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
1354	{
1355	static arch_spinlock_t trace_buf_lock =
1356	(arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
1357	static u32 trace_buf[TRACE_BUF_SIZE];
1358
1359	struct ftrace_event_call *call = &event_bprint;
1360	struct ring_buffer_event *event;
1361	struct ring_buffer *buffer;
1362	struct trace_array *tr = &global_trace;
1363	struct trace_array_cpu *data;
1364	struct bprint_entry *entry;
1365	unsigned long flags;
1366	int disable;
1367	int cpu, len = 0, size, pc;
1368
1369	if (unlikely(tracing_selftest_running \|\| tracing_disabled))
1370	return 0;
1371
1372	/* Don't pollute graph traces with trace_vprintk internals */
1373	pause_graph_tracing();
1374
1375	pc = preempt_count();
1376	preempt_disable_notrace();
1377	cpu = raw_smp_processor_id();
1378	data = tr->data[cpu];
1379
1380	disable = atomic_inc_return(&data->disabled);
1381	if (unlikely(disable != 1))
1382	goto out;
1383
1384	/* Lockdep uses trace_printk for lock tracing */
1385	local_irq_save(flags);
1386	arch_spin_lock(&trace_buf_lock);
1387	len = vbin_printf(trace_buf, TRACE_BUF_SIZE, fmt, args);
1388
1389	if (len > TRACE_BUF_SIZE \|\| len < 0)
1390	goto out_unlock;
1391
1392	size = sizeof(entry) + sizeof(u32) len;
1393	buffer = tr->buffer;
1394	event = trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
1395	flags, pc);
1396	if (!event)
1397	goto out_unlock;
1398	entry = ring_buffer_event_data(event);
1399	entry->ip = ip;
1400	entry->fmt = fmt;
1401
1402	memcpy(entry->buf, trace_buf, sizeof(u32) * len);
1403	if (!filter_check_discard(call, entry, buffer, event)) {
1404	ring_buffer_unlock_commit(buffer, event);
1405	ftrace_trace_stack(buffer, flags, 6, pc);
1406	}
1407
1408	out_unlock:
1409	arch_spin_unlock(&trace_buf_lock);
1410	local_irq_restore(flags);
1411
1412	out:
1413	atomic_dec_return(&data->disabled);
1414	preempt_enable_notrace();
1415	unpause_graph_tracing();
1416
1417	return len;
1418	}
1419	EXPORT_SYMBOL_GPL(trace_vbprintk);
1420
1421	int trace_array_printk(struct trace_array *tr,
1422	unsigned long ip, const char *fmt, ...)
1423	{
1424	int ret;
1425	va_list ap;
1426
1427	if (!(trace_flags & TRACE_ITER_PRINTK))
1428	return 0;
1429
1430	va_start(ap, fmt);
1431	ret = trace_array_vprintk(tr, ip, fmt, ap);
1432	va_end(ap);
1433	return ret;
1434	}
1435
1436	int trace_array_vprintk(struct trace_array *tr,
1437	unsigned long ip, const char *fmt, va_list args)
1438	{
1439	static arch_spinlock_t trace_buf_lock = __ARCH_SPIN_LOCK_UNLOCKED;
1440	static char trace_buf[TRACE_BUF_SIZE];
1441
1442	struct ftrace_event_call *call = &event_print;
1443	struct ring_buffer_event *event;
1444	struct ring_buffer *buffer;
1445	struct trace_array_cpu *data;
1446	int cpu, len = 0, size, pc;
1447	struct print_entry *entry;
1448	unsigned long irq_flags;
1449	int disable;
1450
1451	if (tracing_disabled \|\| tracing_selftest_running)
1452	return 0;
1453
1454	pc = preempt_count();
1455	preempt_disable_notrace();
1456	cpu = raw_smp_processor_id();
1457	data = tr->data[cpu];
1458
1459	disable = atomic_inc_return(&data->disabled);
1460	if (unlikely(disable != 1))
1461	goto out;
1462
1463	pause_graph_tracing();
1464	raw_local_irq_save(irq_flags);
1465	arch_spin_lock(&trace_buf_lock);
1466	len = vsnprintf(trace_buf, TRACE_BUF_SIZE, fmt, args);
1467
1468	size = sizeof(*entry) + len + 1;
1469	buffer = tr->buffer;
1470	event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
1471	irq_flags, pc);
1472	if (!event)
1473	goto out_unlock;
1474	entry = ring_buffer_event_data(event);
1475	entry->ip = ip;
1476
1477	memcpy(&entry->buf, trace_buf, len);
1478	entry->buf[len] = '\0';
1479	if (!filter_check_discard(call, entry, buffer, event)) {
1480	ring_buffer_unlock_commit(buffer, event);
1481	ftrace_trace_stack(buffer, irq_flags, 6, pc);
1482	}
1483
1484	out_unlock:
1485	arch_spin_unlock(&trace_buf_lock);
1486	raw_local_irq_restore(irq_flags);
1487	unpause_graph_tracing();
1488	out:
1489	atomic_dec_return(&data->disabled);
1490	preempt_enable_notrace();
1491
1492	return len;
1493	}
1494
1495	int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
1496	{
1497	return trace_array_vprintk(&global_trace, ip, fmt, args);
1498	}
1499	EXPORT_SYMBOL_GPL(trace_vprintk);
1500
1501	static void trace_iterator_increment(struct trace_iterator *iter)
1502	{
1503	/* Don't allow ftrace to trace into the ring buffers */
1504	ftrace_disable_cpu();
1505
1506	iter->idx++;
1507	if (iter->buffer_iter[iter->cpu])
1508	ring_buffer_read(iter->buffer_iter[iter->cpu], NULL);
1509
1510	ftrace_enable_cpu();
1511	}
1512
1513	static struct trace_entry *
1514	peek_next_entry(struct trace_iterator iter, int cpu, u64 ts,
1515	unsigned long *lost_events)
1516	{
1517	struct ring_buffer_event *event;
1518	struct ring_buffer_iter *buf_iter = iter->buffer_iter[cpu];
1519
1520	/* Don't allow ftrace to trace into the ring buffers */
1521	ftrace_disable_cpu();
1522
1523	if (buf_iter)
1524	event = ring_buffer_iter_peek(buf_iter, ts);
1525	else
1526	event = ring_buffer_peek(iter->tr->buffer, cpu, ts,
1527	lost_events);
1528
1529	ftrace_enable_cpu();
1530
1531	return event ? ring_buffer_event_data(event) : NULL;
1532	}
1533
1534	static struct trace_entry *
1535	__find_next_entry(struct trace_iterator iter, int ent_cpu,
1536	unsigned long missing_events, u64 ent_ts)
1537	{
1538	struct ring_buffer *buffer = iter->tr->buffer;
1539	struct trace_entry ent, next = NULL;
1540	unsigned long lost_events = 0, next_lost = 0;
1541	int cpu_file = iter->cpu_file;
1542	u64 next_ts = 0, ts;
1543	int next_cpu = -1;
1544	int cpu;
1545
1546	/*
1547	* If we are in a per_cpu trace file, don't bother by iterating over
1548	* all cpu and peek directly.
1549	*/
1550	if (cpu_file > TRACE_PIPE_ALL_CPU) {
1551	if (ring_buffer_empty_cpu(buffer, cpu_file))
1552	return NULL;
1553	ent = peek_next_entry(iter, cpu_file, ent_ts, missing_events);
1554	if (ent_cpu)
1555	*ent_cpu = cpu_file;
1556
1557	return ent;
1558	}
1559
1560	for_each_tracing_cpu(cpu) {
1561
1562	if (ring_buffer_empty_cpu(buffer, cpu))
1563	continue;
1564
1565	ent = peek_next_entry(iter, cpu, &ts, &lost_events);
1566
1567	/*
1568	* Pick the entry with the smallest timestamp:
1569	*/
1570	if (ent && (!next \|\| ts < next_ts)) {
1571	next = ent;
1572	next_cpu = cpu;
1573	next_ts = ts;
1574	next_lost = lost_events;
1575	}
1576	}
1577
1578	if (ent_cpu)
1579	*ent_cpu = next_cpu;
1580
1581	if (ent_ts)
1582	*ent_ts = next_ts;
1583
1584	if (missing_events)
1585	*missing_events = next_lost;
1586
1587	return next;
1588	}
1589
1590	/* Find the next real entry, without updating the iterator itself */
1591	struct trace_entry trace_find_next_entry(struct trace_iterator iter,
1592	int ent_cpu, u64 ent_ts)
1593	{
1594	return __find_next_entry(iter, ent_cpu, NULL, ent_ts);
1595	}
1596
1597	/* Find the next real entry, and increment the iterator to the next entry */
1598	void trace_find_next_entry_inc(struct trace_iterator iter)
1599	{
1600	iter->ent = __find_next_entry(iter, &iter->cpu,
1601	&iter->lost_events, &iter->ts);
1602
1603	if (iter->ent)
1604	trace_iterator_increment(iter);
1605
1606	return iter->ent ? iter : NULL;
1607	}
1608
1609	static void trace_consume(struct trace_iterator *iter)
1610	{
1611	/* Don't allow ftrace to trace into the ring buffers */
1612	ftrace_disable_cpu();
1613	ring_buffer_consume(iter->tr->buffer, iter->cpu, &iter->ts,
1614	&iter->lost_events);
1615	ftrace_enable_cpu();
1616	}
1617
1618	static void s_next(struct seq_file m, void v, loff_t pos)
1619	{
1620	struct trace_iterator *iter = m->private;
1621	int i = (int)*pos;
1622	void *ent;
1623
1624	WARN_ON_ONCE(iter->leftover);
1625
1626	(*pos)++;
1627
1628	/* can't go backwards */
1629	if (iter->idx > i)
1630	return NULL;
1631
1632	if (iter->idx < 0)
1633	ent = trace_find_next_entry_inc(iter);
1634	else
1635	ent = iter;
1636
1637	while (ent && iter->idx < i)
1638	ent = trace_find_next_entry_inc(iter);
1639
1640	iter->pos = *pos;
1641
1642	return ent;
1643	}
1644
1645	void tracing_iter_reset(struct trace_iterator *iter, int cpu)
1646	{
1647	struct trace_array *tr = iter->tr;
1648	struct ring_buffer_event *event;
1649	struct ring_buffer_iter *buf_iter;
1650	unsigned long entries = 0;
1651	u64 ts;
1652
1653	tr->data[cpu]->skipped_entries = 0;
1654
1655	if (!iter->buffer_iter[cpu])
1656	return;
1657
1658	buf_iter = iter->buffer_iter[cpu];
1659	ring_buffer_iter_reset(buf_iter);
1660
1661	/*
1662	* We could have the case with the max latency tracers
1663	* that a reset never took place on a cpu. This is evident
1664	* by the timestamp being before the start of the buffer.
1665	*/
1666	while ((event = ring_buffer_iter_peek(buf_iter, &ts))) {
1667	if (ts >= iter->tr->time_start)
1668	break;
1669	entries++;
1670	ring_buffer_read(buf_iter, NULL);
1671	}
1672
1673	tr->data[cpu]->skipped_entries = entries;
1674	}
1675
1676	/*
1677	* The current tracer is copied to avoid a global locking
1678	* all around.
1679	*/
1680	static void s_start(struct seq_file m, loff_t *pos)
1681	{
1682	struct trace_iterator *iter = m->private;
1683	static struct tracer *old_tracer;
1684	int cpu_file = iter->cpu_file;
1685	void *p = NULL;
1686	loff_t l = 0;
1687	int cpu;
1688
1689	/* copy the tracer to avoid using a global lock all around */
1690	mutex_lock(&trace_types_lock);
1691	if (unlikely(old_tracer != current_trace && current_trace)) {
1692	old_tracer = current_trace;
1693	iter->trace = current_trace;
1694	}
1695	mutex_unlock(&trace_types_lock);
1696
1697	atomic_inc(&trace_record_cmdline_disabled);
1698
1699	if (*pos != iter->pos) {
1700	iter->ent = NULL;
1701	iter->cpu = 0;
1702	iter->idx = -1;
1703
1704	ftrace_disable_cpu();
1705
1706	if (cpu_file == TRACE_PIPE_ALL_CPU) {
1707	for_each_tracing_cpu(cpu)
1708	tracing_iter_reset(iter, cpu);
1709	} else
1710	tracing_iter_reset(iter, cpu_file);
1711
1712	ftrace_enable_cpu();
1713
1714	iter->leftover = 0;
1715	for (p = iter; p && l < *pos; p = s_next(m, p, &l))
1716	;
1717
1718	} else {
1719	/*
1720	* If we overflowed the seq_file before, then we want
1721	* to just reuse the trace_seq buffer again.
1722	*/
1723	if (iter->leftover)
1724	p = iter;
1725	else {
1726	l = *pos - 1;
1727	p = s_next(m, p, &l);
1728	}
1729	}
1730
1731	trace_event_read_lock();
1732	trace_access_lock(cpu_file);
1733	return p;
1734	}
1735
1736	static void s_stop(struct seq_file m, void p)
1737	{
1738	struct trace_iterator *iter = m->private;
1739
1740	atomic_dec(&trace_record_cmdline_disabled);
1741	trace_access_unlock(iter->cpu_file);
1742	trace_event_read_unlock();
1743	}
1744
1745	static void print_lat_help_header(struct seq_file *m)
1746	{
1747	seq_puts(m, "# _------=> CPU# \n");
1748	seq_puts(m, "# / _-----=> irqs-off \n");
1749	seq_puts(m, "# \| / _----=> need-resched \n");
1750	seq_puts(m, "# \|\| / _---=> hardirq/softirq \n");
1751	seq_puts(m, "# \|\|\| / _--=> preempt-depth \n");
1752	seq_puts(m, "# \|\|\|\| /_--=> lock-depth \n");
1753	seq_puts(m, "# \|\|\|\|\|/ delay \n");
1754	seq_puts(m, "# cmd pid \|\|\|\|\|\| time \| caller \n");
1755	seq_puts(m, "# \\ / \|\|\|\|\|\| \\ \| / \n");
1756	}
1757
1758	static void print_func_help_header(struct seq_file *m)
1759	{
1760	seq_puts(m, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
1761	seq_puts(m, "# \| \| \| \| \|\n");
1762	}
1763
1764
1765	void
1766	print_trace_header(struct seq_file m, struct trace_iterator iter)
1767	{
1768	unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1769	struct trace_array *tr = iter->tr;
1770	struct trace_array_cpu *data = tr->data[tr->cpu];
1771	struct tracer *type = current_trace;
1772	unsigned long entries = 0;
1773	unsigned long total = 0;
1774	unsigned long count;
1775	const char *name = "preemption";
1776	int cpu;
1777
1778	if (type)
1779	name = type->name;
1780
1781
1782	for_each_tracing_cpu(cpu) {
1783	count = ring_buffer_entries_cpu(tr->buffer, cpu);
1784	/*
1785	* If this buffer has skipped entries, then we hold all
1786	* entries for the trace and we need to ignore the
1787	* ones before the time stamp.
1788	*/
1789	if (tr->data[cpu]->skipped_entries) {
1790	count -= tr->data[cpu]->skipped_entries;
1791	/* total is the same as the entries */
1792	total += count;
1793	} else
1794	total += count +
1795	ring_buffer_overrun_cpu(tr->buffer, cpu);
1796	entries += count;
1797	}
1798
1799	seq_printf(m, "# %s latency trace v1.1.5 on %s\n",
1800	name, UTS_RELEASE);
1801	seq_puts(m, "# -----------------------------------"
1802	"---------------------------------\n");
1803	seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d \|"
1804	" (M:%s VP:%d, KP:%d, SP:%d HP:%d",
1805	nsecs_to_usecs(data->saved_latency),
1806	entries,
1807	total,
1808	tr->cpu,
1809	#if defined(CONFIG_PREEMPT_NONE)
1810	"server",
1811	#elif defined(CONFIG_PREEMPT_VOLUNTARY)
1812	"desktop",
1813	#elif defined(CONFIG_PREEMPT)
1814	"preempt",
1815	#else
1816	"unknown",
1817	#endif
1818	/* These are reserved for later use */
1819	0, 0, 0, 0);
1820	#ifdef CONFIG_SMP
1821	seq_printf(m, " #P:%d)\n", num_online_cpus());
1822	#else
1823	seq_puts(m, ")\n");
1824	#endif
1825	seq_puts(m, "# -----------------\n");
1826	seq_printf(m, "# \| task: %.16s-%d "
1827	"(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
1828	data->comm, data->pid, data->uid, data->nice,
1829	data->policy, data->rt_priority);
1830	seq_puts(m, "# -----------------\n");
1831
1832	if (data->critical_start) {
1833	seq_puts(m, "# => started at: ");
1834	seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
1835	trace_print_seq(m, &iter->seq);
1836	seq_puts(m, "\n# => ended at: ");
1837	seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
1838	trace_print_seq(m, &iter->seq);
1839	seq_puts(m, "\n#\n");
1840	}
1841
1842	seq_puts(m, "#\n");
1843	}
1844
1845	static void test_cpu_buff_start(struct trace_iterator *iter)
1846	{
1847	struct trace_seq *s = &iter->seq;
1848
1849	if (!(trace_flags & TRACE_ITER_ANNOTATE))
1850	return;
1851
1852	if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
1853	return;
1854
1855	if (cpumask_test_cpu(iter->cpu, iter->started))
1856	return;
1857
1858	if (iter->tr->data[iter->cpu]->skipped_entries)
1859	return;
1860
1861	cpumask_set_cpu(iter->cpu, iter->started);
1862
1863	/* Don't print started cpu buffer for the first entry of the trace */
1864	if (iter->idx > 1)
1865	trace_seq_printf(s, "##### CPU %u buffer started ####\n",
1866	iter->cpu);
1867	}
1868
1869	static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
1870	{
1871	struct trace_seq *s = &iter->seq;
1872	unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
1873	struct trace_entry *entry;
1874	struct trace_event *event;
1875
1876	entry = iter->ent;
1877
1878	test_cpu_buff_start(iter);
1879
1880	event = ftrace_find_event(entry->type);
1881
1882	if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1883	if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
1884	if (!trace_print_lat_context(iter))
1885	goto partial;
1886	} else {
1887	if (!trace_print_context(iter))
1888	goto partial;
1889	}
1890	}
1891
1892	if (event)
1893	return event->funcs->trace(iter, sym_flags, event);
1894
1895	if (!trace_seq_printf(s, "Unknown type %d\n", entry->type))
1896	goto partial;
1897
1898	return TRACE_TYPE_HANDLED;
1899	partial:
1900	return TRACE_TYPE_PARTIAL_LINE;
1901	}
1902
1903	static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
1904	{
1905	struct trace_seq *s = &iter->seq;
1906	struct trace_entry *entry;
1907	struct trace_event *event;
1908
1909	entry = iter->ent;
1910
1911	if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1912	if (!trace_seq_printf(s, "%d %d %llu ",
1913	entry->pid, iter->cpu, iter->ts))
1914	goto partial;
1915	}
1916
1917	event = ftrace_find_event(entry->type);
1918	if (event)
1919	return event->funcs->raw(iter, 0, event);
1920
1921	if (!trace_seq_printf(s, "%d ?\n", entry->type))
1922	goto partial;
1923
1924	return TRACE_TYPE_HANDLED;
1925	partial:
1926	return TRACE_TYPE_PARTIAL_LINE;
1927	}
1928
1929	static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
1930	{
1931	struct trace_seq *s = &iter->seq;
1932	unsigned char newline = '\n';
1933	struct trace_entry *entry;
1934	struct trace_event *event;
1935
1936	entry = iter->ent;
1937
1938	if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1939	SEQ_PUT_HEX_FIELD_RET(s, entry->pid);
1940	SEQ_PUT_HEX_FIELD_RET(s, iter->cpu);
1941	SEQ_PUT_HEX_FIELD_RET(s, iter->ts);
1942	}
1943
1944	event = ftrace_find_event(entry->type);
1945	if (event) {
1946	enum print_line_t ret = event->funcs->hex(iter, 0, event);
1947	if (ret != TRACE_TYPE_HANDLED)
1948	return ret;
1949	}
1950
1951	SEQ_PUT_FIELD_RET(s, newline);
1952
1953	return TRACE_TYPE_HANDLED;
1954	}
1955
1956	static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
1957	{
1958	struct trace_seq *s = &iter->seq;
1959	struct trace_entry *entry;
1960	struct trace_event *event;
1961
1962	entry = iter->ent;
1963
1964	if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
1965	SEQ_PUT_FIELD_RET(s, entry->pid);
1966	SEQ_PUT_FIELD_RET(s, iter->cpu);
1967	SEQ_PUT_FIELD_RET(s, iter->ts);
1968	}
1969
1970	event = ftrace_find_event(entry->type);
1971	return event ? event->funcs->binary(iter, 0, event) :
1972	TRACE_TYPE_HANDLED;
1973	}
1974
1975	int trace_empty(struct trace_iterator *iter)
1976	{
1977	int cpu;
1978
1979	/* If we are looking at one CPU buffer, only check that one */
1980	if (iter->cpu_file != TRACE_PIPE_ALL_CPU) {
1981	cpu = iter->cpu_file;
1982	if (iter->buffer_iter[cpu]) {
1983	if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
1984	return 0;
1985	} else {
1986	if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu))
1987	return 0;
1988	}
1989	return 1;
1990	}
1991
1992	for_each_tracing_cpu(cpu) {
1993	if (iter->buffer_iter[cpu]) {
1994	if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
1995	return 0;
1996	} else {
1997	if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu))
1998	return 0;
1999	}
2000	}
2001
2002	return 1;
2003	}
2004
2005	/* Called with trace_event_read_lock() held. */
2006	enum print_line_t print_trace_line(struct trace_iterator *iter)
2007	{
2008	enum print_line_t ret;
2009
2010	if (iter->lost_events)
2011	trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
2012	iter->cpu, iter->lost_events);
2013
2014	if (iter->trace && iter->trace->print_line) {
2015	ret = iter->trace->print_line(iter);
2016	if (ret != TRACE_TYPE_UNHANDLED)
2017	return ret;
2018	}
2019
2020	if (iter->ent->type == TRACE_BPRINT &&
2021	trace_flags & TRACE_ITER_PRINTK &&
2022	trace_flags & TRACE_ITER_PRINTK_MSGONLY)
2023	return trace_print_bprintk_msg_only(iter);
2024
2025	if (iter->ent->type == TRACE_PRINT &&
2026	trace_flags & TRACE_ITER_PRINTK &&
2027	trace_flags & TRACE_ITER_PRINTK_MSGONLY)
2028	return trace_print_printk_msg_only(iter);
2029
2030	if (trace_flags & TRACE_ITER_BIN)
2031	return print_bin_fmt(iter);
2032
2033	if (trace_flags & TRACE_ITER_HEX)
2034	return print_hex_fmt(iter);
2035
2036	if (trace_flags & TRACE_ITER_RAW)
2037	return print_raw_fmt(iter);
2038
2039	return print_trace_fmt(iter);
2040	}
2041
2042	void trace_default_header(struct seq_file *m)
2043	{
2044	struct trace_iterator *iter = m->private;
2045
2046	if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
2047	/* print nothing if the buffers are empty */
2048	if (trace_empty(iter))
2049	return;
2050	print_trace_header(m, iter);
2051	if (!(trace_flags & TRACE_ITER_VERBOSE))
2052	print_lat_help_header(m);
2053	} else {
2054	if (!(trace_flags & TRACE_ITER_VERBOSE))
2055	print_func_help_header(m);
2056	}
2057	}
2058
2059	static int s_show(struct seq_file m, void v)
2060	{
2061	struct trace_iterator *iter = v;
2062	int ret;
2063
2064	if (iter->ent == NULL) {
2065	if (iter->tr) {
2066	seq_printf(m, "# tracer: %s\n", iter->trace->name);
2067	seq_puts(m, "#\n");
2068	}
2069	if (iter->trace && iter->trace->print_header)
2070	iter->trace->print_header(m);
2071	else
2072	trace_default_header(m);
2073
2074	} else if (iter->leftover) {
2075	/*
2076	* If we filled the seq_file buffer earlier, we
2077	* want to just show it now.
2078	*/
2079	ret = trace_print_seq(m, &iter->seq);
2080
2081	/* ret should this time be zero, but you never know */
2082	iter->leftover = ret;
2083
2084	} else {
2085	print_trace_line(iter);
2086	ret = trace_print_seq(m, &iter->seq);
2087	/*
2088	* If we overflow the seq_file buffer, then it will
2089	* ask us for this data again at start up.
2090	* Use that instead.
2091	* ret is 0 if seq_file write succeeded.
2092	* -1 otherwise.
2093	*/
2094	iter->leftover = ret;
2095	}
2096
2097	return 0;
2098	}
2099
2100	static const struct seq_operations tracer_seq_ops = {
2101	.start = s_start,
2102	.next = s_next,
2103	.stop = s_stop,
2104	.show = s_show,
2105	};
2106
2107	static struct trace_iterator *
2108	__tracing_open(struct inode inode, struct file file)
2109	{
2110	long cpu_file = (long) inode->i_private;
2111	void *fail_ret = ERR_PTR(-ENOMEM);
2112	struct trace_iterator *iter;
2113	struct seq_file *m;
2114	int cpu, ret;
2115
2116	if (tracing_disabled)
2117	return ERR_PTR(-ENODEV);
2118
2119	iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2120	if (!iter)
2121	return ERR_PTR(-ENOMEM);
2122
2123	/*
2124	* We make a copy of the current tracer to avoid concurrent
2125	* changes on it while we are reading.
2126	*/
2127	mutex_lock(&trace_types_lock);
2128	iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL);
2129	if (!iter->trace)
2130	goto fail;
2131
2132	if (current_trace)
2133	iter->trace = current_trace;
2134
2135	if (!zalloc_cpumask_var(&iter->started, GFP_KERNEL))
2136	goto fail;
2137
2138	if (current_trace && current_trace->print_max)
2139	iter->tr = &max_tr;
2140	else
2141	iter->tr = &global_trace;
2142	iter->pos = -1;
2143	mutex_init(&iter->mutex);
2144	iter->cpu_file = cpu_file;
2145
2146	/* Notify the tracer early; before we stop tracing. */
2147	if (iter->trace && iter->trace->open)
2148	iter->trace->open(iter);
2149
2150	/* Annotate start of buffers if we had overruns */
2151	if (ring_buffer_overruns(iter->tr->buffer))
2152	iter->iter_flags \|= TRACE_FILE_ANNOTATE;
2153
2154	/* stop the trace while dumping */
2155	tracing_stop();
2156
2157	if (iter->cpu_file == TRACE_PIPE_ALL_CPU) {
2158	for_each_tracing_cpu(cpu) {
2159	iter->buffer_iter[cpu] =
2160	ring_buffer_read_prepare(iter->tr->buffer, cpu);
2161	}
2162	ring_buffer_read_prepare_sync();
2163	for_each_tracing_cpu(cpu) {
2164	ring_buffer_read_start(iter->buffer_iter[cpu]);
2165	tracing_iter_reset(iter, cpu);
2166	}
2167	} else {
2168	cpu = iter->cpu_file;
2169	iter->buffer_iter[cpu] =
2170	ring_buffer_read_prepare(iter->tr->buffer, cpu);
2171	ring_buffer_read_prepare_sync();
2172	ring_buffer_read_start(iter->buffer_iter[cpu]);
2173	tracing_iter_reset(iter, cpu);
2174	}
2175
2176	ret = seq_open(file, &tracer_seq_ops);
2177	if (ret < 0) {
2178	fail_ret = ERR_PTR(ret);
2179	goto fail_buffer;
2180	}
2181
2182	m = file->private_data;
2183	m->private = iter;
2184
2185	mutex_unlock(&trace_types_lock);
2186
2187	return iter;
2188
2189	fail_buffer:
2190	for_each_tracing_cpu(cpu) {
2191	if (iter->buffer_iter[cpu])
2192	ring_buffer_read_finish(iter->buffer_iter[cpu]);
2193	}
2194	free_cpumask_var(iter->started);
2195	tracing_start();
2196	fail:
2197	mutex_unlock(&trace_types_lock);
2198	kfree(iter->trace);
2199	kfree(iter);
2200
2201	return fail_ret;
2202	}
2203
2204	int tracing_open_generic(struct inode inode, struct file filp)
2205	{
2206	if (tracing_disabled)
2207	return -ENODEV;
2208
2209	filp->private_data = inode->i_private;
2210	return 0;
2211	}
2212
2213	static int tracing_release(struct inode inode, struct file file)
2214	{
2215	struct seq_file *m = file->private_data;
2216	struct trace_iterator *iter;
2217	int cpu;
2218
2219	if (!(file->f_mode & FMODE_READ))
2220	return 0;
2221
2222	iter = m->private;
2223
2224	mutex_lock(&trace_types_lock);
2225	for_each_tracing_cpu(cpu) {
2226	if (iter->buffer_iter[cpu])
2227	ring_buffer_read_finish(iter->buffer_iter[cpu]);
2228	}
2229
2230	if (iter->trace && iter->trace->close)
2231	iter->trace->close(iter);
2232
2233	/* reenable tracing if it was previously enabled */
2234	tracing_start();
2235	mutex_unlock(&trace_types_lock);
2236
2237	seq_release(inode, file);
2238	mutex_destroy(&iter->mutex);
2239	free_cpumask_var(iter->started);
2240	kfree(iter->trace);
2241	kfree(iter);
2242	return 0;
2243	}
2244
2245	static int tracing_open(struct inode inode, struct file file)
2246	{
2247	struct trace_iterator *iter;
2248	int ret = 0;
2249
2250	/* If this file was open for write, then erase contents */
2251	if ((file->f_mode & FMODE_WRITE) &&
2252	(file->f_flags & O_TRUNC)) {
2253	long cpu = (long) inode->i_private;
2254
2255	if (cpu == TRACE_PIPE_ALL_CPU)
2256	tracing_reset_online_cpus(&global_trace);
2257	else
2258	tracing_reset(&global_trace, cpu);
2259	}
2260
2261	if (file->f_mode & FMODE_READ) {
2262	iter = __tracing_open(inode, file);
2263	if (IS_ERR(iter))
2264	ret = PTR_ERR(iter);
2265	else if (trace_flags & TRACE_ITER_LATENCY_FMT)
2266	iter->iter_flags \|= TRACE_FILE_LAT_FMT;
2267	}
2268	return ret;
2269	}
2270
2271	static void *
2272	t_next(struct seq_file m, void v, loff_t *pos)
2273	{
2274	struct tracer *t = v;
2275
2276	(*pos)++;
2277
2278	if (t)
2279	t = t->next;
2280
2281	return t;
2282	}
2283
2284	static void t_start(struct seq_file m, loff_t *pos)
2285	{
2286	struct tracer *t;
2287	loff_t l = 0;
2288
2289	mutex_lock(&trace_types_lock);
2290	for (t = trace_types; t && l < *pos; t = t_next(m, t, &l))
2291	;
2292
2293	return t;
2294	}
2295
2296	static void t_stop(struct seq_file m, void p)
2297	{
2298	mutex_unlock(&trace_types_lock);
2299	}
2300
2301	static int t_show(struct seq_file m, void v)
2302	{
2303	struct tracer *t = v;
2304
2305	if (!t)
2306	return 0;
2307
2308	seq_printf(m, "%s", t->name);
2309	if (t->next)
2310	seq_putc(m, ' ');
2311	else
2312	seq_putc(m, '\n');
2313
2314	return 0;
2315	}
2316
2317	static const struct seq_operations show_traces_seq_ops = {
2318	.start = t_start,
2319	.next = t_next,
2320	.stop = t_stop,
2321	.show = t_show,
2322	};
2323
2324	static int show_traces_open(struct inode inode, struct file file)
2325	{
2326	if (tracing_disabled)
2327	return -ENODEV;
2328
2329	return seq_open(file, &show_traces_seq_ops);
2330	}
2331
2332	static ssize_t
2333	tracing_write_stub(struct file filp, const char __user ubuf,
2334	size_t count, loff_t *ppos)
2335	{
2336	return count;
2337	}
2338
2339	static loff_t tracing_seek(struct file *file, loff_t offset, int origin)
2340	{
2341	if (file->f_mode & FMODE_READ)
2342	return seq_lseek(file, offset, origin);
2343	else
2344	return 0;
2345	}
2346
2347	static const struct file_operations tracing_fops = {
2348	.open = tracing_open,
2349	.read = seq_read,
2350	.write = tracing_write_stub,
2351	.llseek = tracing_seek,
2352	.release = tracing_release,
2353	};
2354
2355	static const struct file_operations show_traces_fops = {
2356	.open = show_traces_open,
2357	.read = seq_read,
2358	.release = seq_release,
2359	.llseek = seq_lseek,
2360	};
2361
2362	/*
2363	* Only trace on a CPU if the bitmask is set:
2364	*/
2365	static cpumask_var_t tracing_cpumask;
2366
2367	/*
2368	* The tracer itself will not take this lock, but still we want
2369	* to provide a consistent cpumask to user-space:
2370	*/
2371	static DEFINE_MUTEX(tracing_cpumask_update_lock);
2372
2373	/*
2374	* Temporary storage for the character representation of the
2375	* CPU bitmask (and one more byte for the newline):
2376	*/
2377	static char mask_str[NR_CPUS + 1];
2378
2379	static ssize_t
2380	tracing_cpumask_read(struct file filp, char __user ubuf,
2381	size_t count, loff_t *ppos)
2382	{
2383	int len;
2384
2385	mutex_lock(&tracing_cpumask_update_lock);
2386
2387	len = cpumask_scnprintf(mask_str, count, tracing_cpumask);
2388	if (count - len < 2) {
2389	count = -EINVAL;
2390	goto out_err;
2391	}
2392	len += sprintf(mask_str + len, "\n");
2393	count = simple_read_from_buffer(ubuf, count, ppos, mask_str, NR_CPUS+1);
2394
2395	out_err:
2396	mutex_unlock(&tracing_cpumask_update_lock);
2397
2398	return count;
2399	}
2400
2401	static ssize_t
2402	tracing_cpumask_write(struct file filp, const char __user ubuf,
2403	size_t count, loff_t *ppos)
2404	{
2405	int err, cpu;
2406	cpumask_var_t tracing_cpumask_new;
2407
2408	if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
2409	return -ENOMEM;
2410
2411	err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
2412	if (err)
2413	goto err_unlock;
2414
2415	mutex_lock(&tracing_cpumask_update_lock);
2416
2417	local_irq_disable();
2418	arch_spin_lock(&ftrace_max_lock);
2419	for_each_tracing_cpu(cpu) {
2420	/*
2421	* Increase/decrease the disabled counter if we are
2422	* about to flip a bit in the cpumask:
2423	*/
2424	if (cpumask_test_cpu(cpu, tracing_cpumask) &&
2425	!cpumask_test_cpu(cpu, tracing_cpumask_new)) {
2426	atomic_inc(&global_trace.data[cpu]->disabled);
2427	}
2428	if (!cpumask_test_cpu(cpu, tracing_cpumask) &&
2429	cpumask_test_cpu(cpu, tracing_cpumask_new)) {
2430	atomic_dec(&global_trace.data[cpu]->disabled);
2431	}
2432	}
2433	arch_spin_unlock(&ftrace_max_lock);
2434	local_irq_enable();
2435
2436	cpumask_copy(tracing_cpumask, tracing_cpumask_new);
2437
2438	mutex_unlock(&tracing_cpumask_update_lock);
2439	free_cpumask_var(tracing_cpumask_new);
2440
2441	return count;
2442
2443	err_unlock:
2444	free_cpumask_var(tracing_cpumask_new);
2445
2446	return err;
2447	}
2448
2449	static const struct file_operations tracing_cpumask_fops = {
2450	.open = tracing_open_generic,
2451	.read = tracing_cpumask_read,
2452	.write = tracing_cpumask_write,
2453	.llseek = generic_file_llseek,
2454	};
2455
2456	static int tracing_trace_options_show(struct seq_file m, void v)
2457	{
2458	struct tracer_opt *trace_opts;
2459	u32 tracer_flags;
2460	int i;
2461
2462	mutex_lock(&trace_types_lock);
2463	tracer_flags = current_trace->flags->val;
2464	trace_opts = current_trace->flags->opts;
2465
2466	for (i = 0; trace_options[i]; i++) {
2467	if (trace_flags & (1 << i))
2468	seq_printf(m, "%s\n", trace_options[i]);
2469	else
2470	seq_printf(m, "no%s\n", trace_options[i]);
2471	}
2472
2473	for (i = 0; trace_opts[i].name; i++) {
2474	if (tracer_flags & trace_opts[i].bit)
2475	seq_printf(m, "%s\n", trace_opts[i].name);
2476	else
2477	seq_printf(m, "no%s\n", trace_opts[i].name);
2478	}
2479	mutex_unlock(&trace_types_lock);
2480
2481	return 0;
2482	}
2483
2484	static int __set_tracer_option(struct tracer *trace,
2485	struct tracer_flags *tracer_flags,
2486	struct tracer_opt *opts, int neg)
2487	{
2488	int ret;
2489
2490	ret = trace->set_flag(tracer_flags->val, opts->bit, !neg);
2491	if (ret)
2492	return ret;
2493
2494	if (neg)
2495	tracer_flags->val &= ~opts->bit;
2496	else
2497	tracer_flags->val \|= opts->bit;
2498	return 0;
2499	}
2500
2501	/* Try to assign a tracer specific option */
2502	static int set_tracer_option(struct tracer trace, char cmp, int neg)
2503	{
2504	struct tracer_flags *tracer_flags = trace->flags;
2505	struct tracer_opt *opts = NULL;
2506	int i;
2507
2508	for (i = 0; tracer_flags->opts[i].name; i++) {
2509	opts = &tracer_flags->opts[i];
2510
2511	if (strcmp(cmp, opts->name) == 0)
2512	return __set_tracer_option(trace, trace->flags,
2513	opts, neg);
2514	}
2515
2516	return -EINVAL;
2517	}
2518
2519	static void set_tracer_flags(unsigned int mask, int enabled)
2520	{
2521	/* do nothing if flag is already set */
2522	if (!!(trace_flags & mask) == !!enabled)
2523	return;
2524
2525	if (enabled)
2526	trace_flags \|= mask;
2527	else
2528	trace_flags &= ~mask;
2529
2530	if (mask == TRACE_ITER_RECORD_CMD)
2531	trace_event_enable_cmd_record(enabled);
2532	}
2533
2534	static ssize_t
2535	tracing_trace_options_write(struct file filp, const char __user ubuf,
2536	size_t cnt, loff_t *ppos)
2537	{
2538	char buf[64];
2539	char *cmp;
2540	int neg = 0;
2541	int ret;
2542	int i;
2543
2544	if (cnt >= sizeof(buf))
2545	return -EINVAL;
2546
2547	if (copy_from_user(&buf, ubuf, cnt))
2548	return -EFAULT;
2549
2550	buf[cnt] = 0;
2551	cmp = strstrip(buf);
2552
2553	if (strncmp(cmp, "no", 2) == 0) {
2554	neg = 1;
2555	cmp += 2;
2556	}
2557
2558	for (i = 0; trace_options[i]; i++) {
2559	if (strcmp(cmp, trace_options[i]) == 0) {
2560	set_tracer_flags(1 << i, !neg);
2561	break;
2562	}
2563	}
2564
2565	/* If no option could be set, test the specific tracer options */
2566	if (!trace_options[i]) {
2567	mutex_lock(&trace_types_lock);
2568	ret = set_tracer_option(current_trace, cmp, neg);
2569	mutex_unlock(&trace_types_lock);
2570	if (ret)
2571	return ret;
2572	}
2573
2574	*ppos += cnt;
2575
2576	return cnt;
2577	}
2578
2579	static int tracing_trace_options_open(struct inode inode, struct file file)
2580	{
2581	if (tracing_disabled)
2582	return -ENODEV;
2583	return single_open(file, tracing_trace_options_show, NULL);
2584	}
2585
2586	static const struct file_operations tracing_iter_fops = {
2587	.open = tracing_trace_options_open,
2588	.read = seq_read,
2589	.llseek = seq_lseek,
2590	.release = single_release,
2591	.write = tracing_trace_options_write,
2592	};
2593
2594	static const char readme_msg[] =
2595	"tracing mini-HOWTO:\n\n"
2596	"# mount -t debugfs nodev /sys/kernel/debug\n\n"
2597	"# cat /sys/kernel/debug/tracing/available_tracers\n"
2598	"wakeup preemptirqsoff preemptoff irqsoff function sched_switch nop\n\n"
2599	"# cat /sys/kernel/debug/tracing/current_tracer\n"
2600	"nop\n"
2601	"# echo sched_switch > /sys/kernel/debug/tracing/current_tracer\n"
2602	"# cat /sys/kernel/debug/tracing/current_tracer\n"
2603	"sched_switch\n"
2604	"# cat /sys/kernel/debug/tracing/trace_options\n"
2605	"noprint-parent nosym-offset nosym-addr noverbose\n"
2606	"# echo print-parent > /sys/kernel/debug/tracing/trace_options\n"
2607	"# echo 1 > /sys/kernel/debug/tracing/tracing_enabled\n"
2608	"# cat /sys/kernel/debug/tracing/trace > /tmp/trace.txt\n"
2609	"# echo 0 > /sys/kernel/debug/tracing/tracing_enabled\n"
2610	;
2611
2612	static ssize_t
2613	tracing_readme_read(struct file filp, char __user ubuf,
2614	size_t cnt, loff_t *ppos)
2615	{
2616	return simple_read_from_buffer(ubuf, cnt, ppos,
2617	readme_msg, strlen(readme_msg));
2618	}
2619
2620	static const struct file_operations tracing_readme_fops = {
2621	.open = tracing_open_generic,
2622	.read = tracing_readme_read,
2623	.llseek = generic_file_llseek,
2624	};
2625
2626	static ssize_t
2627	tracing_saved_cmdlines_read(struct file file, char __user ubuf,
2628	size_t cnt, loff_t *ppos)
2629	{
2630	char *buf_comm;
2631	char *file_buf;
2632	char *buf;
2633	int len = 0;
2634	int pid;
2635	int i;
2636
2637	file_buf = kmalloc(SAVED_CMDLINES*(16+TASK_COMM_LEN), GFP_KERNEL);
2638	if (!file_buf)
2639	return -ENOMEM;
2640
2641	buf_comm = kmalloc(TASK_COMM_LEN, GFP_KERNEL);
2642	if (!buf_comm) {
2643	kfree(file_buf);
2644	return -ENOMEM;
2645	}
2646
2647	buf = file_buf;
2648
2649	for (i = 0; i < SAVED_CMDLINES; i++) {
2650	int r;
2651
2652	pid = map_cmdline_to_pid[i];
2653	if (pid == -1 \|\| pid == NO_CMDLINE_MAP)
2654	continue;
2655
2656	trace_find_cmdline(pid, buf_comm);
2657	r = sprintf(buf, "%d %s\n", pid, buf_comm);
2658	buf += r;
2659	len += r;
2660	}
2661
2662	len = simple_read_from_buffer(ubuf, cnt, ppos,
2663	file_buf, len);
2664
2665	kfree(file_buf);
2666	kfree(buf_comm);
2667
2668	return len;
2669	}
2670
2671	static const struct file_operations tracing_saved_cmdlines_fops = {
2672	.open = tracing_open_generic,
2673	.read = tracing_saved_cmdlines_read,
2674	.llseek = generic_file_llseek,
2675	};
2676
2677	static ssize_t
2678	tracing_ctrl_read(struct file filp, char __user ubuf,
2679	size_t cnt, loff_t *ppos)
2680	{
2681	char buf[64];
2682	int r;
2683
2684	r = sprintf(buf, "%u\n", tracer_enabled);
2685	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2686	}
2687
2688	static ssize_t
2689	tracing_ctrl_write(struct file filp, const char __user ubuf,
2690	size_t cnt, loff_t *ppos)
2691	{
2692	struct trace_array *tr = filp->private_data;
2693	char buf[64];
2694	unsigned long val;
2695	int ret;
2696
2697	if (cnt >= sizeof(buf))
2698	return -EINVAL;
2699
2700	if (copy_from_user(&buf, ubuf, cnt))
2701	return -EFAULT;
2702
2703	buf[cnt] = 0;
2704
2705	ret = strict_strtoul(buf, 10, &val);
2706	if (ret < 0)
2707	return ret;
2708
2709	val = !!val;
2710
2711	mutex_lock(&trace_types_lock);
2712	if (tracer_enabled ^ val) {
2713	if (val) {
2714	tracer_enabled = 1;
2715	if (current_trace->start)
2716	current_trace->start(tr);
2717	tracing_start();
2718	} else {
2719	tracer_enabled = 0;
2720	tracing_stop();
2721	if (current_trace->stop)
2722	current_trace->stop(tr);
2723	}
2724	}
2725	mutex_unlock(&trace_types_lock);
2726
2727	*ppos += cnt;
2728
2729	return cnt;
2730	}
2731
2732	static ssize_t
2733	tracing_set_trace_read(struct file filp, char __user ubuf,
2734	size_t cnt, loff_t *ppos)
2735	{
2736	char buf[MAX_TRACER_SIZE+2];
2737	int r;
2738
2739	mutex_lock(&trace_types_lock);
2740	if (current_trace)
2741	r = sprintf(buf, "%s\n", current_trace->name);
2742	else
2743	r = sprintf(buf, "\n");
2744	mutex_unlock(&trace_types_lock);
2745
2746	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2747	}
2748
2749	int tracer_init(struct tracer t, struct trace_array tr)
2750	{
2751	tracing_reset_online_cpus(tr);
2752	return t->init(tr);
2753	}
2754
2755	static int tracing_resize_ring_buffer(unsigned long size)
2756	{
2757	int ret;
2758
2759	/*
2760	* If kernel or user changes the size of the ring buffer
2761	* we use the size that was given, and we can forget about
2762	* expanding it later.
2763	*/
2764	ring_buffer_expanded = 1;
2765
2766	ret = ring_buffer_resize(global_trace.buffer, size);
2767	if (ret < 0)
2768	return ret;
2769
2770	if (!current_trace->use_max_tr)
2771	goto out;
2772
2773	ret = ring_buffer_resize(max_tr.buffer, size);
2774	if (ret < 0) {
2775	int r;
2776
2777	r = ring_buffer_resize(global_trace.buffer,
2778	global_trace.entries);
2779	if (r < 0) {
2780	/*
2781	* AARGH! We are left with different
2782	* size max buffer!!!!
2783	* The max buffer is our "snapshot" buffer.
2784	* When a tracer needs a snapshot (one of the
2785	* latency tracers), it swaps the max buffer
2786	* with the saved snap shot. We succeeded to
2787	* update the size of the main buffer, but failed to
2788	* update the size of the max buffer. But when we tried
2789	* to reset the main buffer to the original size, we
2790	* failed there too. This is very unlikely to
2791	* happen, but if it does, warn and kill all
2792	* tracing.
2793	*/
2794	WARN_ON(1);
2795	tracing_disabled = 1;
2796	}
2797	return ret;
2798	}
2799
2800	max_tr.entries = size;
2801	out:
2802	global_trace.entries = size;
2803
2804	return ret;
2805	}
2806
2807
2808	/**
2809	* tracing_update_buffers - used by tracing facility to expand ring buffers
2810	*
2811	* To save on memory when the tracing is never used on a system with it
2812	* configured in. The ring buffers are set to a minimum size. But once
2813	* a user starts to use the tracing facility, then they need to grow
2814	* to their default size.
2815	*
2816	* This function is to be called when a tracer is about to be used.
2817	*/
2818	int tracing_update_buffers(void)
2819	{
2820	int ret = 0;
2821
2822	mutex_lock(&trace_types_lock);
2823	if (!ring_buffer_expanded)
2824	ret = tracing_resize_ring_buffer(trace_buf_size);
2825	mutex_unlock(&trace_types_lock);
2826
2827	return ret;
2828	}
2829
2830	struct trace_option_dentry;
2831
2832	static struct trace_option_dentry *
2833	create_trace_option_files(struct tracer *tracer);
2834
2835	static void
2836	destroy_trace_option_files(struct trace_option_dentry *topts);
2837
2838	static int tracing_set_tracer(const char *buf)
2839	{
2840	static struct trace_option_dentry *topts;
2841	struct trace_array *tr = &global_trace;
2842	struct tracer *t;
2843	int ret = 0;
2844
2845	mutex_lock(&trace_types_lock);
2846
2847	if (!ring_buffer_expanded) {
2848	ret = tracing_resize_ring_buffer(trace_buf_size);
2849	if (ret < 0)
2850	goto out;
2851	ret = 0;
2852	}
2853
2854	for (t = trace_types; t; t = t->next) {
2855	if (strcmp(t->name, buf) == 0)
2856	break;
2857	}
2858	if (!t) {
2859	ret = -EINVAL;
2860	goto out;
2861	}
2862	if (t == current_trace)
2863	goto out;
2864
2865	trace_branch_disable();
2866	if (current_trace && current_trace->reset)
2867	current_trace->reset(tr);
2868	if (current_trace && current_trace->use_max_tr) {
2869	/*
2870	* We don't free the ring buffer. instead, resize it because
2871	* The max_tr ring buffer has some state (e.g. ring->clock) and
2872	* we want preserve it.
2873	*/
2874	ring_buffer_resize(max_tr.buffer, 1);
2875	max_tr.entries = 1;
2876	}
2877	destroy_trace_option_files(topts);
2878
2879	current_trace = t;
2880
2881	topts = create_trace_option_files(current_trace);
2882	if (current_trace->use_max_tr) {
2883	ret = ring_buffer_resize(max_tr.buffer, global_trace.entries);
2884	if (ret < 0)
2885	goto out;
2886	max_tr.entries = global_trace.entries;
2887	}
2888
2889	if (t->init) {
2890	ret = tracer_init(t, tr);
2891	if (ret)
2892	goto out;
2893	}
2894
2895	trace_branch_enable(tr);
2896	out:
2897	mutex_unlock(&trace_types_lock);
2898
2899	return ret;
2900	}
2901
2902	static ssize_t
2903	tracing_set_trace_write(struct file filp, const char __user ubuf,
2904	size_t cnt, loff_t *ppos)
2905	{
2906	char buf[MAX_TRACER_SIZE+1];
2907	int i;
2908	size_t ret;
2909	int err;
2910
2911	ret = cnt;
2912
2913	if (cnt > MAX_TRACER_SIZE)
2914	cnt = MAX_TRACER_SIZE;
2915
2916	if (copy_from_user(&buf, ubuf, cnt))
2917	return -EFAULT;
2918
2919	buf[cnt] = 0;
2920
2921	/* strip ending whitespace. */
2922	for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
2923	buf[i] = 0;
2924
2925	err = tracing_set_tracer(buf);
2926	if (err)
2927	return err;
2928
2929	*ppos += ret;
2930
2931	return ret;
2932	}
2933
2934	static ssize_t
2935	tracing_max_lat_read(struct file filp, char __user ubuf,
2936	size_t cnt, loff_t *ppos)
2937	{
2938	unsigned long *ptr = filp->private_data;
2939	char buf[64];
2940	int r;
2941
2942	r = snprintf(buf, sizeof(buf), "%ld\n",
2943	ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(ptr));
2944	if (r > sizeof(buf))
2945	r = sizeof(buf);
2946	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2947	}
2948
2949	static ssize_t
2950	tracing_max_lat_write(struct file filp, const char __user ubuf,
2951	size_t cnt, loff_t *ppos)
2952	{
2953	unsigned long *ptr = filp->private_data;
2954	char buf[64];
2955	unsigned long val;
2956	int ret;
2957
2958	if (cnt >= sizeof(buf))
2959	return -EINVAL;
2960
2961	if (copy_from_user(&buf, ubuf, cnt))
2962	return -EFAULT;
2963
2964	buf[cnt] = 0;
2965
2966	ret = strict_strtoul(buf, 10, &val);
2967	if (ret < 0)
2968	return ret;
2969
2970	ptr = val 1000;
2971
2972	return cnt;
2973	}
2974
2975	static int tracing_open_pipe(struct inode inode, struct file filp)
2976	{
2977	long cpu_file = (long) inode->i_private;
2978	struct trace_iterator *iter;
2979	int ret = 0;
2980
2981	if (tracing_disabled)
2982	return -ENODEV;
2983
2984	mutex_lock(&trace_types_lock);
2985
2986	/* create a buffer to store the information to pass to userspace */
2987	iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2988	if (!iter) {
2989	ret = -ENOMEM;
2990	goto out;
2991	}
2992
2993	/*
2994	* We make a copy of the current tracer to avoid concurrent
2995	* changes on it while we are reading.
2996	*/
2997	iter->trace = kmalloc(sizeof(*iter->trace), GFP_KERNEL);
2998	if (!iter->trace) {
2999	ret = -ENOMEM;
3000	goto fail;
3001	}
3002	if (current_trace)
3003	iter->trace = current_trace;
3004
3005	if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
3006	ret = -ENOMEM;
3007	goto fail;
3008	}
3009
3010	/* trace pipe does not show start of buffer */
3011	cpumask_setall(iter->started);
3012
3013	if (trace_flags & TRACE_ITER_LATENCY_FMT)
3014	iter->iter_flags \|= TRACE_FILE_LAT_FMT;
3015
3016	iter->cpu_file = cpu_file;
3017	iter->tr = &global_trace;
3018	mutex_init(&iter->mutex);
3019	filp->private_data = iter;
3020
3021	if (iter->trace->pipe_open)
3022	iter->trace->pipe_open(iter);
3023
3024	nonseekable_open(inode, filp);
3025	out:
3026	mutex_unlock(&trace_types_lock);
3027	return ret;
3028
3029	fail:
3030	kfree(iter->trace);
3031	kfree(iter);
3032	mutex_unlock(&trace_types_lock);
3033	return ret;
3034	}
3035
3036	static int tracing_release_pipe(struct inode inode, struct file file)
3037	{
3038	struct trace_iterator *iter = file->private_data;
3039
3040	mutex_lock(&trace_types_lock);
3041
3042	if (iter->trace->pipe_close)
3043	iter->trace->pipe_close(iter);
3044
3045	mutex_unlock(&trace_types_lock);
3046
3047	free_cpumask_var(iter->started);
3048	mutex_destroy(&iter->mutex);
3049	kfree(iter->trace);
3050	kfree(iter);
3051
3052	return 0;
3053	}
3054
3055	static unsigned int
3056	tracing_poll_pipe(struct file filp, poll_table poll_table)
3057	{
3058	struct trace_iterator *iter = filp->private_data;
3059
3060	if (trace_flags & TRACE_ITER_BLOCK) {
3061	/*
3062	* Always select as readable when in blocking mode
3063	*/
3064	return POLLIN \| POLLRDNORM;
3065	} else {
3066	if (!trace_empty(iter))
3067	return POLLIN \| POLLRDNORM;
3068	poll_wait(filp, &trace_wait, poll_table);
3069	if (!trace_empty(iter))
3070	return POLLIN \| POLLRDNORM;
3071
3072	return 0;
3073	}
3074	}
3075
3076
3077	void default_wait_pipe(struct trace_iterator *iter)
3078	{
3079	DEFINE_WAIT(wait);
3080
3081	prepare_to_wait(&trace_wait, &wait, TASK_INTERRUPTIBLE);
3082
3083	if (trace_empty(iter))
3084	schedule();
3085
3086	finish_wait(&trace_wait, &wait);
3087	}
3088
3089	/*
3090	* This is a make-shift waitqueue.
3091	* A tracer might use this callback on some rare cases:
3092	*
3093	* 1) the current tracer might hold the runqueue lock when it wakes up
3094	* a reader, hence a deadlock (sched, function, and function graph tracers)
3095	* 2) the function tracers, trace all functions, we don't want
3096	* the overhead of calling wake_up and friends
3097	* (and tracing them too)
3098	*
3099	* Anyway, this is really very primitive wakeup.
3100	*/
3101	void poll_wait_pipe(struct trace_iterator *iter)
3102	{
3103	set_current_state(TASK_INTERRUPTIBLE);
3104	/* sleep for 100 msecs, and try again. */
3105	schedule_timeout(HZ / 10);
3106	}
3107
3108	/* Must be called with trace_types_lock mutex held. */
3109	static int tracing_wait_pipe(struct file *filp)
3110	{
3111	struct trace_iterator *iter = filp->private_data;
3112
3113	while (trace_empty(iter)) {
3114
3115	if ((filp->f_flags & O_NONBLOCK)) {
3116	return -EAGAIN;
3117	}
3118
3119	mutex_unlock(&iter->mutex);
3120
3121	iter->trace->wait_pipe(iter);
3122
3123	mutex_lock(&iter->mutex);
3124
3125	if (signal_pending(current))
3126	return -EINTR;
3127
3128	/*
3129	* We block until we read something and tracing is disabled.
3130	* We still block if tracing is disabled, but we have never
3131	* read anything. This allows a user to cat this file, and
3132	* then enable tracing. But after we have read something,
3133	* we give an EOF when tracing is again disabled.
3134	*
3135	* iter->pos will be 0 if we haven't read anything.
3136	*/
3137	if (!tracer_enabled && iter->pos)
3138	break;
3139	}
3140
3141	return 1;
3142	}
3143
3144	/*
3145	* Consumer reader.
3146	*/
3147	static ssize_t
3148	tracing_read_pipe(struct file filp, char __user ubuf,
3149	size_t cnt, loff_t *ppos)
3150	{
3151	struct trace_iterator *iter = filp->private_data;
3152	static struct tracer *old_tracer;
3153	ssize_t sret;
3154
3155	/* return any leftover data */
3156	sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
3157	if (sret != -EBUSY)
3158	return sret;
3159
3160	trace_seq_init(&iter->seq);
3161
3162	/* copy the tracer to avoid using a global lock all around */
3163	mutex_lock(&trace_types_lock);
3164	if (unlikely(old_tracer != current_trace && current_trace)) {
3165	old_tracer = current_trace;
3166	iter->trace = current_trace;
3167	}
3168	mutex_unlock(&trace_types_lock);
3169
3170	/*
3171	* Avoid more than one consumer on a single file descriptor
3172	* This is just a matter of traces coherency, the ring buffer itself
3173	* is protected.
3174	*/
3175	mutex_lock(&iter->mutex);
3176	if (iter->trace->read) {
3177	sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
3178	if (sret)
3179	goto out;
3180	}
3181
3182	waitagain:
3183	sret = tracing_wait_pipe(filp);
3184	if (sret <= 0)
3185	goto out;
3186
3187	/* stop when tracing is finished */
3188	if (trace_empty(iter)) {
3189	sret = 0;
3190	goto out;
3191	}
3192
3193	if (cnt >= PAGE_SIZE)
3194	cnt = PAGE_SIZE - 1;
3195
3196	/* reset all but tr, trace, and overruns */
3197	memset(&iter->seq, 0,
3198	sizeof(struct trace_iterator) -
3199	offsetof(struct trace_iterator, seq));
3200	iter->pos = -1;
3201
3202	trace_event_read_lock();
3203	trace_access_lock(iter->cpu_file);
3204	while (trace_find_next_entry_inc(iter) != NULL) {
3205	enum print_line_t ret;
3206	int len = iter->seq.len;
3207
3208	ret = print_trace_line(iter);
3209	if (ret == TRACE_TYPE_PARTIAL_LINE) {
3210	/* don't print partial lines */
3211	iter->seq.len = len;
3212	break;
3213	}
3214	if (ret != TRACE_TYPE_NO_CONSUME)
3215	trace_consume(iter);
3216
3217	if (iter->seq.len >= cnt)
3218	break;
3219	}
3220	trace_access_unlock(iter->cpu_file);
3221	trace_event_read_unlock();
3222
3223	/* Now copy what we have to the user */
3224	sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
3225	if (iter->seq.readpos >= iter->seq.len)
3226	trace_seq_init(&iter->seq);
3227
3228	/*
3229	* If there was nothing to send to user, inspite of consuming trace
3230	* entries, go back to wait for more entries.
3231	*/
3232	if (sret == -EBUSY)
3233	goto waitagain;
3234
3235	out:
3236	mutex_unlock(&iter->mutex);
3237
3238	return sret;
3239	}
3240
3241	static void tracing_pipe_buf_release(struct pipe_inode_info *pipe,
3242	struct pipe_buffer *buf)
3243	{
3244	__free_page(buf->page);
3245	}
3246
3247	static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
3248	unsigned int idx)
3249	{
3250	__free_page(spd->pages[idx]);
3251	}
3252
3253	static const struct pipe_buf_operations tracing_pipe_buf_ops = {
3254	.can_merge = 0,
3255	.map = generic_pipe_buf_map,
3256	.unmap = generic_pipe_buf_unmap,
3257	.confirm = generic_pipe_buf_confirm,
3258	.release = tracing_pipe_buf_release,
3259	.steal = generic_pipe_buf_steal,
3260	.get = generic_pipe_buf_get,
3261	};
3262
3263	static size_t
3264	tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
3265	{
3266	size_t count;
3267	int ret;
3268
3269	/* Seq buffer is page-sized, exactly what we need. */
3270	for (;;) {
3271	count = iter->seq.len;
3272	ret = print_trace_line(iter);
3273	count = iter->seq.len - count;
3274	if (rem < count) {
3275	rem = 0;
3276	iter->seq.len -= count;
3277	break;
3278	}
3279	if (ret == TRACE_TYPE_PARTIAL_LINE) {
3280	iter->seq.len -= count;
3281	break;
3282	}
3283
3284	if (ret != TRACE_TYPE_NO_CONSUME)
3285	trace_consume(iter);
3286	rem -= count;
3287	if (!trace_find_next_entry_inc(iter)) {
3288	rem = 0;
3289	iter->ent = NULL;
3290	break;
3291	}
3292	}
3293
3294	return rem;
3295	}
3296
3297	static ssize_t tracing_splice_read_pipe(struct file *filp,
3298	loff_t *ppos,
3299	struct pipe_inode_info *pipe,
3300	size_t len,
3301	unsigned int flags)
3302	{
3303	struct page *pages_def[PIPE_DEF_BUFFERS];
3304	struct partial_page partial_def[PIPE_DEF_BUFFERS];
3305	struct trace_iterator *iter = filp->private_data;
3306	struct splice_pipe_desc spd = {
3307	.pages = pages_def,
3308	.partial = partial_def,
3309	.nr_pages = 0, /* This gets updated below. */
3310	.flags = flags,
3311	.ops = &tracing_pipe_buf_ops,
3312	.spd_release = tracing_spd_release_pipe,
3313	};
3314	static struct tracer *old_tracer;
3315	ssize_t ret;
3316	size_t rem;
3317	unsigned int i;
3318
3319	if (splice_grow_spd(pipe, &spd))
3320	return -ENOMEM;
3321
3322	/* copy the tracer to avoid using a global lock all around */
3323	mutex_lock(&trace_types_lock);
3324	if (unlikely(old_tracer != current_trace && current_trace)) {
3325	old_tracer = current_trace;
3326	iter->trace = current_trace;
3327	}
3328	mutex_unlock(&trace_types_lock);
3329
3330	mutex_lock(&iter->mutex);
3331
3332	if (iter->trace->splice_read) {
3333	ret = iter->trace->splice_read(iter, filp,
3334	ppos, pipe, len, flags);
3335	if (ret)
3336	goto out_err;
3337	}
3338
3339	ret = tracing_wait_pipe(filp);
3340	if (ret <= 0)
3341	goto out_err;
3342
3343	if (!iter->ent && !trace_find_next_entry_inc(iter)) {
3344	ret = -EFAULT;
3345	goto out_err;
3346	}
3347
3348	trace_event_read_lock();
3349	trace_access_lock(iter->cpu_file);
3350
3351	/* Fill as many pages as possible. */
3352	for (i = 0, rem = len; i < pipe->buffers && rem; i++) {
3353	spd.pages[i] = alloc_page(GFP_KERNEL);
3354	if (!spd.pages[i])
3355	break;
3356
3357	rem = tracing_fill_pipe_page(rem, iter);
3358
3359	/* Copy the data into the page, so we can start over. */
3360	ret = trace_seq_to_buffer(&iter->seq,
3361	page_address(spd.pages[i]),
3362	iter->seq.len);
3363	if (ret < 0) {
3364	__free_page(spd.pages[i]);
3365	break;
3366	}
3367	spd.partial[i].offset = 0;
3368	spd.partial[i].len = iter->seq.len;
3369
3370	trace_seq_init(&iter->seq);
3371	}
3372
3373	trace_access_unlock(iter->cpu_file);
3374	trace_event_read_unlock();
3375	mutex_unlock(&iter->mutex);
3376
3377	spd.nr_pages = i;
3378
3379	ret = splice_to_pipe(pipe, &spd);
3380	out:
3381	splice_shrink_spd(pipe, &spd);
3382	return ret;
3383
3384	out_err:
3385	mutex_unlock(&iter->mutex);
3386	goto out;
3387	}
3388
3389	static ssize_t
3390	tracing_entries_read(struct file filp, char __user ubuf,
3391	size_t cnt, loff_t *ppos)
3392	{
3393	struct trace_array *tr = filp->private_data;
3394	char buf[96];
3395	int r;
3396
3397	mutex_lock(&trace_types_lock);
3398	if (!ring_buffer_expanded)
3399	r = sprintf(buf, "%lu (expanded: %lu)\n",
3400	tr->entries >> 10,
3401	trace_buf_size >> 10);
3402	else
3403	r = sprintf(buf, "%lu\n", tr->entries >> 10);
3404	mutex_unlock(&trace_types_lock);
3405
3406	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
3407	}
3408
3409	static ssize_t
3410	tracing_entries_write(struct file filp, const char __user ubuf,
3411	size_t cnt, loff_t *ppos)
3412	{
3413	unsigned long val;
3414	char buf[64];
3415	int ret, cpu;
3416
3417	if (cnt >= sizeof(buf))
3418	return -EINVAL;
3419
3420	if (copy_from_user(&buf, ubuf, cnt))
3421	return -EFAULT;
3422
3423	buf[cnt] = 0;
3424
3425	ret = strict_strtoul(buf, 10, &val);
3426	if (ret < 0)
3427	return ret;
3428
3429	/* must have at least 1 entry */
3430	if (!val)
3431	return -EINVAL;
3432
3433	mutex_lock(&trace_types_lock);
3434
3435	tracing_stop();
3436
3437	/* disable all cpu buffers */
3438	for_each_tracing_cpu(cpu) {
3439	if (global_trace.data[cpu])
3440	atomic_inc(&global_trace.data[cpu]->disabled);
3441	if (max_tr.data[cpu])
3442	atomic_inc(&max_tr.data[cpu]->disabled);
3443	}
3444
3445	/* value is in KB */
3446	val <<= 10;
3447
3448	if (val != global_trace.entries) {
3449	ret = tracing_resize_ring_buffer(val);
3450	if (ret < 0) {
3451	cnt = ret;
3452	goto out;
3453	}
3454	}
3455
3456	*ppos += cnt;
3457
3458	/* If check pages failed, return ENOMEM */
3459	if (tracing_disabled)
3460	cnt = -ENOMEM;
3461	out:
3462	for_each_tracing_cpu(cpu) {
3463	if (global_trace.data[cpu])
3464	atomic_dec(&global_trace.data[cpu]->disabled);
3465	if (max_tr.data[cpu])
3466	atomic_dec(&max_tr.data[cpu]->disabled);
3467	}
3468
3469	tracing_start();
3470	mutex_unlock(&trace_types_lock);
3471
3472	return cnt;
3473	}
3474
3475	static int mark_printk(const char *fmt, ...)
3476	{
3477	int ret;
3478	va_list args;
3479	va_start(args, fmt);
3480	ret = trace_vprintk(0, fmt, args);
3481	va_end(args);
3482	return ret;
3483	}
3484
3485	static ssize_t
3486	tracing_mark_write(struct file filp, const char __user ubuf,
3487	size_t cnt, loff_t *fpos)
3488	{
3489	char *buf;
3490	size_t written;
3491
3492	if (tracing_disabled)
3493	return -EINVAL;
3494
3495	if (cnt > TRACE_BUF_SIZE)
3496	cnt = TRACE_BUF_SIZE;
3497
3498	buf = kmalloc(cnt + 2, GFP_KERNEL);
3499	if (buf == NULL)
3500	return -ENOMEM;
3501
3502	if (copy_from_user(buf, ubuf, cnt)) {
3503	kfree(buf);
3504	return -EFAULT;
3505	}
3506	if (buf[cnt-1] != '\n') {
3507	buf[cnt] = '\n';
3508	buf[cnt+1] = '\0';
3509	} else
3510	buf[cnt] = '\0';
3511
3512	written = mark_printk("%s", buf);
3513	kfree(buf);
3514	*fpos += written;
3515
3516	/* don't tell userspace we wrote more - it might confuse them */
3517	if (written > cnt)
3518	written = cnt;
3519
3520	return written;
3521	}
3522
3523	static int tracing_clock_show(struct seq_file m, void v)
3524	{
3525	int i;
3526
3527	for (i = 0; i < ARRAY_SIZE(trace_clocks); i++)
3528	seq_printf(m,
3529	"%s%s%s%s", i ? " " : "",
3530	i == trace_clock_id ? "[" : "", trace_clocks[i].name,
3531	i == trace_clock_id ? "]" : "");
3532	seq_putc(m, '\n');
3533
3534	return 0;
3535	}
3536
3537	static ssize_t tracing_clock_write(struct file filp, const char __user ubuf,
3538	size_t cnt, loff_t *fpos)
3539	{
3540	char buf[64];
3541	const char *clockstr;
3542	int i;
3543
3544	if (cnt >= sizeof(buf))
3545	return -EINVAL;
3546
3547	if (copy_from_user(&buf, ubuf, cnt))
3548	return -EFAULT;
3549
3550	buf[cnt] = 0;
3551
3552	clockstr = strstrip(buf);
3553
3554	for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) {
3555	if (strcmp(trace_clocks[i].name, clockstr) == 0)
3556	break;
3557	}
3558	if (i == ARRAY_SIZE(trace_clocks))
3559	return -EINVAL;
3560
3561	trace_clock_id = i;
3562
3563	mutex_lock(&trace_types_lock);
3564
3565	ring_buffer_set_clock(global_trace.buffer, trace_clocks[i].func);
3566	if (max_tr.buffer)
3567	ring_buffer_set_clock(max_tr.buffer, trace_clocks[i].func);
3568
3569	mutex_unlock(&trace_types_lock);
3570
3571	*fpos += cnt;
3572
3573	return cnt;
3574	}
3575
3576	static int tracing_clock_open(struct inode inode, struct file file)
3577	{
3578	if (tracing_disabled)
3579	return -ENODEV;
3580	return single_open(file, tracing_clock_show, NULL);
3581	}
3582
3583	static const struct file_operations tracing_max_lat_fops = {
3584	.open = tracing_open_generic,
3585	.read = tracing_max_lat_read,
3586	.write = tracing_max_lat_write,
3587	.llseek = generic_file_llseek,
3588	};
3589
3590	static const struct file_operations tracing_ctrl_fops = {
3591	.open = tracing_open_generic,
3592	.read = tracing_ctrl_read,
3593	.write = tracing_ctrl_write,
3594	.llseek = generic_file_llseek,
3595	};
3596
3597	static const struct file_operations set_tracer_fops = {
3598	.open = tracing_open_generic,
3599	.read = tracing_set_trace_read,
3600	.write = tracing_set_trace_write,
3601	.llseek = generic_file_llseek,
3602	};
3603
3604	static const struct file_operations tracing_pipe_fops = {
3605	.open = tracing_open_pipe,
3606	.poll = tracing_poll_pipe,
3607	.read = tracing_read_pipe,
3608	.splice_read = tracing_splice_read_pipe,
3609	.release = tracing_release_pipe,
3610	.llseek = no_llseek,
3611	};
3612
3613	static const struct file_operations tracing_entries_fops = {
3614	.open = tracing_open_generic,
3615	.read = tracing_entries_read,
3616	.write = tracing_entries_write,
3617	.llseek = generic_file_llseek,
3618	};
3619
3620	static const struct file_operations tracing_mark_fops = {
3621	.open = tracing_open_generic,
3622	.write = tracing_mark_write,
3623	.llseek = generic_file_llseek,
3624	};
3625
3626	static const struct file_operations trace_clock_fops = {
3627	.open = tracing_clock_open,
3628	.read = seq_read,
3629	.llseek = seq_lseek,
3630	.release = single_release,
3631	.write = tracing_clock_write,
3632	};
3633
3634	struct ftrace_buffer_info {
3635	struct trace_array *tr;
3636	void *spare;
3637	int cpu;
3638	unsigned int read;
3639	};
3640
3641	static int tracing_buffers_open(struct inode inode, struct file filp)
3642	{
3643	int cpu = (int)(long)inode->i_private;
3644	struct ftrace_buffer_info *info;
3645
3646	if (tracing_disabled)
3647	return -ENODEV;
3648
3649	info = kzalloc(sizeof(*info), GFP_KERNEL);
3650	if (!info)
3651	return -ENOMEM;
3652
3653	info->tr = &global_trace;
3654	info->cpu = cpu;
3655	info->spare = NULL;
3656	/* Force reading ring buffer for first read */
3657	info->read = (unsigned int)-1;
3658
3659	filp->private_data = info;
3660
3661	return nonseekable_open(inode, filp);
3662	}
3663
3664	static ssize_t
3665	tracing_buffers_read(struct file filp, char __user ubuf,
3666	size_t count, loff_t *ppos)
3667	{
3668	struct ftrace_buffer_info *info = filp->private_data;
3669	ssize_t ret;
3670	size_t size;
3671
3672	if (!count)
3673	return 0;
3674
3675	if (!info->spare)
3676	info->spare = ring_buffer_alloc_read_page(info->tr->buffer);
3677	if (!info->spare)
3678	return -ENOMEM;
3679
3680	/* Do we have previous read data to read? */
3681	if (info->read < PAGE_SIZE)
3682	goto read;
3683
3684	info->read = 0;
3685
3686	trace_access_lock(info->cpu);
3687	ret = ring_buffer_read_page(info->tr->buffer,
3688	&info->spare,
3689	count,
3690	info->cpu, 0);
3691	trace_access_unlock(info->cpu);
3692	if (ret < 0)
3693	return 0;
3694
3695	read:
3696	size = PAGE_SIZE - info->read;
3697	if (size > count)
3698	size = count;
3699
3700	ret = copy_to_user(ubuf, info->spare + info->read, size);
3701	if (ret == size)
3702	return -EFAULT;
3703	size -= ret;
3704
3705	*ppos += size;
3706	info->read += size;
3707
3708	return size;
3709	}
3710
3711	static int tracing_buffers_release(struct inode inode, struct file file)
3712	{
3713	struct ftrace_buffer_info *info = file->private_data;
3714
3715	if (info->spare)
3716	ring_buffer_free_read_page(info->tr->buffer, info->spare);
3717	kfree(info);
3718
3719	return 0;
3720	}
3721
3722	struct buffer_ref {
3723	struct ring_buffer *buffer;
3724	void *page;
3725	int ref;
3726	};
3727
3728	static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
3729	struct pipe_buffer *buf)
3730	{
3731	struct buffer_ref ref = (struct buffer_ref )buf->private;
3732
3733	if (--ref->ref)
3734	return;
3735
3736	ring_buffer_free_read_page(ref->buffer, ref->page);
3737	kfree(ref);
3738	buf->private = 0;
3739	}
3740
3741	static int buffer_pipe_buf_steal(struct pipe_inode_info *pipe,
3742	struct pipe_buffer *buf)
3743	{
3744	return 1;
3745	}
3746
3747	static void buffer_pipe_buf_get(struct pipe_inode_info *pipe,
3748	struct pipe_buffer *buf)
3749	{
3750	struct buffer_ref ref = (struct buffer_ref )buf->private;
3751
3752	ref->ref++;
3753	}
3754
3755	/* Pipe buffer operations for a buffer. */
3756	static const struct pipe_buf_operations buffer_pipe_buf_ops = {
3757	.can_merge = 0,
3758	.map = generic_pipe_buf_map,
3759	.unmap = generic_pipe_buf_unmap,
3760	.confirm = generic_pipe_buf_confirm,
3761	.release = buffer_pipe_buf_release,
3762	.steal = buffer_pipe_buf_steal,
3763	.get = buffer_pipe_buf_get,
3764	};
3765
3766	/*
3767	* Callback from splice_to_pipe(), if we need to release some pages
3768	* at the end of the spd in case we error'ed out in filling the pipe.
3769	*/
3770	static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
3771	{
3772	struct buffer_ref *ref =
3773	(struct buffer_ref *)spd->partial[i].private;
3774
3775	if (--ref->ref)
3776	return;
3777
3778	ring_buffer_free_read_page(ref->buffer, ref->page);
3779	kfree(ref);
3780	spd->partial[i].private = 0;
3781	}
3782
3783	static ssize_t
3784	tracing_buffers_splice_read(struct file file, loff_t ppos,
3785	struct pipe_inode_info *pipe, size_t len,
3786	unsigned int flags)
3787	{
3788	struct ftrace_buffer_info *info = file->private_data;
3789	struct partial_page partial_def[PIPE_DEF_BUFFERS];
3790	struct page *pages_def[PIPE_DEF_BUFFERS];
3791	struct splice_pipe_desc spd = {
3792	.pages = pages_def,
3793	.partial = partial_def,
3794	.flags = flags,
3795	.ops = &buffer_pipe_buf_ops,
3796	.spd_release = buffer_spd_release,
3797	};
3798	struct buffer_ref *ref;
3799	int entries, size, i;
3800	size_t ret;
3801
3802	if (splice_grow_spd(pipe, &spd))
3803	return -ENOMEM;
3804
3805	if (*ppos & (PAGE_SIZE - 1)) {
3806	WARN_ONCE(1, "Ftrace: previous read must page-align\n");
3807	ret = -EINVAL;
3808	goto out;
3809	}
3810
3811	if (len & (PAGE_SIZE - 1)) {
3812	WARN_ONCE(1, "Ftrace: splice_read should page-align\n");
3813	if (len < PAGE_SIZE) {
3814	ret = -EINVAL;
3815	goto out;
3816	}
3817	len &= PAGE_MASK;
3818	}
3819
3820	trace_access_lock(info->cpu);
3821	entries = ring_buffer_entries_cpu(info->tr->buffer, info->cpu);
3822
3823	for (i = 0; i < pipe->buffers && len && entries; i++, len -= PAGE_SIZE) {
3824	struct page *page;
3825	int r;
3826
3827	ref = kzalloc(sizeof(*ref), GFP_KERNEL);
3828	if (!ref)
3829	break;
3830
3831	ref->ref = 1;
3832	ref->buffer = info->tr->buffer;
3833	ref->page = ring_buffer_alloc_read_page(ref->buffer);
3834	if (!ref->page) {
3835	kfree(ref);
3836	break;
3837	}
3838
3839	r = ring_buffer_read_page(ref->buffer, &ref->page,
3840	len, info->cpu, 1);
3841	if (r < 0) {
3842	ring_buffer_free_read_page(ref->buffer,
3843	ref->page);
3844	kfree(ref);
3845	break;
3846	}
3847
3848	/*
3849	* zero out any left over data, this is going to
3850	* user land.
3851	*/
3852	size = ring_buffer_page_len(ref->page);
3853	if (size < PAGE_SIZE)
3854	memset(ref->page + size, 0, PAGE_SIZE - size);
3855
3856	page = virt_to_page(ref->page);
3857
3858	spd.pages[i] = page;
3859	spd.partial[i].len = PAGE_SIZE;
3860	spd.partial[i].offset = 0;
3861	spd.partial[i].private = (unsigned long)ref;
3862	spd.nr_pages++;
3863	*ppos += PAGE_SIZE;
3864
3865	entries = ring_buffer_entries_cpu(info->tr->buffer, info->cpu);
3866	}
3867
3868	trace_access_unlock(info->cpu);
3869	spd.nr_pages = i;
3870
3871	/* did we read anything? */
3872	if (!spd.nr_pages) {
3873	if (flags & SPLICE_F_NONBLOCK)
3874	ret = -EAGAIN;
3875	else
3876	ret = 0;
3877	/* TODO: block */
3878	goto out;
3879	}
3880
3881	ret = splice_to_pipe(pipe, &spd);
3882	splice_shrink_spd(pipe, &spd);
3883	out:
3884	return ret;
3885	}
3886
3887	static const struct file_operations tracing_buffers_fops = {
3888	.open = tracing_buffers_open,
3889	.read = tracing_buffers_read,
3890	.release = tracing_buffers_release,
3891	.splice_read = tracing_buffers_splice_read,
3892	.llseek = no_llseek,
3893	};
3894
3895	static ssize_t
3896	tracing_stats_read(struct file filp, char __user ubuf,
3897	size_t count, loff_t *ppos)
3898	{
3899	unsigned long cpu = (unsigned long)filp->private_data;
3900	struct trace_array *tr = &global_trace;
3901	struct trace_seq *s;
3902	unsigned long cnt;
3903
3904	s = kmalloc(sizeof(*s), GFP_KERNEL);
3905	if (!s)
3906	return -ENOMEM;
3907
3908	trace_seq_init(s);
3909
3910	cnt = ring_buffer_entries_cpu(tr->buffer, cpu);
3911	trace_seq_printf(s, "entries: %ld\n", cnt);
3912
3913	cnt = ring_buffer_overrun_cpu(tr->buffer, cpu);
3914	trace_seq_printf(s, "overrun: %ld\n", cnt);
3915
3916	cnt = ring_buffer_commit_overrun_cpu(tr->buffer, cpu);
3917	trace_seq_printf(s, "commit overrun: %ld\n", cnt);
3918
3919	count = simple_read_from_buffer(ubuf, count, ppos, s->buffer, s->len);
3920
3921	kfree(s);
3922
3923	return count;
3924	}
3925
3926	static const struct file_operations tracing_stats_fops = {
3927	.open = tracing_open_generic,
3928	.read = tracing_stats_read,
3929	.llseek = generic_file_llseek,
3930	};
3931
3932	#ifdef CONFIG_DYNAMIC_FTRACE
3933
3934	int __weak ftrace_arch_read_dyn_info(char *buf, int size)
3935	{
3936	return 0;
3937	}
3938
3939	static ssize_t
3940	tracing_read_dyn_info(struct file filp, char __user ubuf,
3941	size_t cnt, loff_t *ppos)
3942	{
3943	static char ftrace_dyn_info_buffer[1024];
3944	static DEFINE_MUTEX(dyn_info_mutex);
3945	unsigned long *p = filp->private_data;
3946	char *buf = ftrace_dyn_info_buffer;
3947	int size = ARRAY_SIZE(ftrace_dyn_info_buffer);
3948	int r;
3949
3950	mutex_lock(&dyn_info_mutex);
3951	r = sprintf(buf, "%ld ", *p);
3952
3953	r += ftrace_arch_read_dyn_info(buf+r, (size-1)-r);
3954	buf[r++] = '\n';
3955
3956	r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
3957
3958	mutex_unlock(&dyn_info_mutex);
3959
3960	return r;
3961	}
3962
3963	static const struct file_operations tracing_dyn_info_fops = {
3964	.open = tracing_open_generic,
3965	.read = tracing_read_dyn_info,
3966	.llseek = generic_file_llseek,
3967	};
3968	#endif
3969
3970	static struct dentry *d_tracer;
3971
3972	struct dentry *tracing_init_dentry(void)
3973	{
3974	static int once;
3975
3976	if (d_tracer)
3977	return d_tracer;
3978
3979	if (!debugfs_initialized())
3980	return NULL;
3981
3982	d_tracer = debugfs_create_dir("tracing", NULL);
3983
3984	if (!d_tracer && !once) {
3985	once = 1;
3986	pr_warning("Could not create debugfs directory 'tracing'\n");
3987	return NULL;
3988	}
3989
3990	return d_tracer;
3991	}
3992
3993	static struct dentry *d_percpu;
3994
3995	struct dentry *tracing_dentry_percpu(void)
3996	{
3997	static int once;
3998	struct dentry *d_tracer;
3999
4000	if (d_percpu)
4001	return d_percpu;
4002
4003	d_tracer = tracing_init_dentry();
4004
4005	if (!d_tracer)
4006	return NULL;
4007
4008	d_percpu = debugfs_create_dir("per_cpu", d_tracer);
4009
4010	if (!d_percpu && !once) {
4011	once = 1;
4012	pr_warning("Could not create debugfs directory 'per_cpu'\n");
4013	return NULL;
4014	}
4015
4016	return d_percpu;
4017	}
4018
4019	static void tracing_init_debugfs_percpu(long cpu)
4020	{
4021	struct dentry *d_percpu = tracing_dentry_percpu();
4022	struct dentry *d_cpu;
4023	char cpu_dir[30]; /* 30 characters should be more than enough */
4024
4025	snprintf(cpu_dir, 30, "cpu%ld", cpu);
4026	d_cpu = debugfs_create_dir(cpu_dir, d_percpu);
4027	if (!d_cpu) {
4028	pr_warning("Could not create debugfs '%s' entry\n", cpu_dir);
4029	return;
4030	}
4031
4032	/* per cpu trace_pipe */
4033	trace_create_file("trace_pipe", 0444, d_cpu,
4034	(void *) cpu, &tracing_pipe_fops);
4035
4036	/* per cpu trace */
4037	trace_create_file("trace", 0644, d_cpu,
4038	(void *) cpu, &tracing_fops);
4039
4040	trace_create_file("trace_pipe_raw", 0444, d_cpu,
4041	(void *) cpu, &tracing_buffers_fops);
4042
4043	trace_create_file("stats", 0444, d_cpu,
4044	(void *) cpu, &tracing_stats_fops);
4045	}
4046
4047	#ifdef CONFIG_FTRACE_SELFTEST
4048	/* Let selftest have access to static functions in this file */
4049	#include "trace_selftest.c"
4050	#endif
4051
4052	struct trace_option_dentry {
4053	struct tracer_opt *opt;
4054	struct tracer_flags *flags;
4055	struct dentry *entry;
4056	};
4057
4058	static ssize_t
4059	trace_options_read(struct file filp, char __user ubuf, size_t cnt,
4060	loff_t *ppos)
4061	{
4062	struct trace_option_dentry *topt = filp->private_data;
4063	char *buf;
4064
4065	if (topt->flags->val & topt->opt->bit)
4066	buf = "1\n";
4067	else
4068	buf = "0\n";
4069
4070	return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
4071	}
4072
4073	static ssize_t
4074	trace_options_write(struct file filp, const char __user ubuf, size_t cnt,
4075	loff_t *ppos)
4076	{
4077	struct trace_option_dentry *topt = filp->private_data;
4078	unsigned long val;
4079	char buf[64];
4080	int ret;
4081
4082	if (cnt >= sizeof(buf))
4083	return -EINVAL;
4084
4085	if (copy_from_user(&buf, ubuf, cnt))
4086	return -EFAULT;
4087
4088	buf[cnt] = 0;
4089
4090	ret = strict_strtoul(buf, 10, &val);
4091	if (ret < 0)
4092	return ret;
4093
4094	if (val != 0 && val != 1)
4095	return -EINVAL;
4096
4097	if (!!(topt->flags->val & topt->opt->bit) != val) {
4098	mutex_lock(&trace_types_lock);
4099	ret = __set_tracer_option(current_trace, topt->flags,
4100	topt->opt, !val);
4101	mutex_unlock(&trace_types_lock);
4102	if (ret)
4103	return ret;
4104	}
4105
4106	*ppos += cnt;
4107
4108	return cnt;
4109	}
4110
4111
4112	static const struct file_operations trace_options_fops = {
4113	.open = tracing_open_generic,
4114	.read = trace_options_read,
4115	.write = trace_options_write,
4116	.llseek = generic_file_llseek,
4117	};
4118
4119	static ssize_t
4120	trace_options_core_read(struct file filp, char __user ubuf, size_t cnt,
4121	loff_t *ppos)
4122	{
4123	long index = (long)filp->private_data;
4124	char *buf;
4125
4126	if (trace_flags & (1 << index))
4127	buf = "1\n";
4128	else
4129	buf = "0\n";
4130
4131	return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
4132	}
4133
4134	static ssize_t
4135	trace_options_core_write(struct file filp, const char __user ubuf, size_t cnt,
4136	loff_t *ppos)
4137	{
4138	long index = (long)filp->private_data;
4139	char buf[64];
4140	unsigned long val;
4141	int ret;
4142
4143	if (cnt >= sizeof(buf))
4144	return -EINVAL;
4145
4146	if (copy_from_user(&buf, ubuf, cnt))
4147	return -EFAULT;
4148
4149	buf[cnt] = 0;
4150
4151	ret = strict_strtoul(buf, 10, &val);
4152	if (ret < 0)
4153	return ret;
4154
4155	if (val != 0 && val != 1)
4156	return -EINVAL;
4157	set_tracer_flags(1 << index, val);
4158
4159	*ppos += cnt;
4160
4161	return cnt;
4162	}
4163
4164	static const struct file_operations trace_options_core_fops = {
4165	.open = tracing_open_generic,
4166	.read = trace_options_core_read,
4167	.write = trace_options_core_write,
4168	.llseek = generic_file_llseek,
4169	};
4170
4171	struct dentry trace_create_file(const char name,
4172	mode_t mode,
4173	struct dentry *parent,
4174	void *data,
4175	const struct file_operations *fops)
4176	{
4177	struct dentry *ret;
4178
4179	ret = debugfs_create_file(name, mode, parent, data, fops);
4180	if (!ret)
4181	pr_warning("Could not create debugfs '%s' entry\n", name);
4182
4183	return ret;
4184	}
4185
4186
4187	static struct dentry *trace_options_init_dentry(void)
4188	{
4189	struct dentry *d_tracer;
4190	static struct dentry *t_options;
4191
4192	if (t_options)
4193	return t_options;
4194
4195	d_tracer = tracing_init_dentry();
4196	if (!d_tracer)
4197	return NULL;
4198
4199	t_options = debugfs_create_dir("options", d_tracer);
4200	if (!t_options) {
4201	pr_warning("Could not create debugfs directory 'options'\n");
4202	return NULL;
4203	}
4204
4205	return t_options;
4206	}
4207
4208	static void
4209	create_trace_option_file(struct trace_option_dentry *topt,
4210	struct tracer_flags *flags,
4211	struct tracer_opt *opt)
4212	{
4213	struct dentry *t_options;
4214
4215	t_options = trace_options_init_dentry();
4216	if (!t_options)
4217	return;
4218
4219	topt->flags = flags;
4220	topt->opt = opt;
4221
4222	topt->entry = trace_create_file(opt->name, 0644, t_options, topt,
4223	&trace_options_fops);
4224
4225	}
4226
4227	static struct trace_option_dentry *
4228	create_trace_option_files(struct tracer *tracer)
4229	{
4230	struct trace_option_dentry *topts;
4231	struct tracer_flags *flags;
4232	struct tracer_opt *opts;
4233	int cnt;
4234
4235	if (!tracer)
4236	return NULL;
4237
4238	flags = tracer->flags;
4239
4240	if (!flags \|\| !flags->opts)
4241	return NULL;
4242
4243	opts = flags->opts;
4244
4245	for (cnt = 0; opts[cnt].name; cnt++)
4246	;
4247
4248	topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL);
4249	if (!topts)
4250	return NULL;
4251
4252	for (cnt = 0; opts[cnt].name; cnt++)
4253	create_trace_option_file(&topts[cnt], flags,
4254	&opts[cnt]);
4255
4256	return topts;
4257	}
4258
4259	static void
4260	destroy_trace_option_files(struct trace_option_dentry *topts)
4261	{
4262	int cnt;
4263
4264	if (!topts)
4265	return;
4266
4267	for (cnt = 0; topts[cnt].opt; cnt++) {
4268	if (topts[cnt].entry)
4269	debugfs_remove(topts[cnt].entry);
4270	}
4271
4272	kfree(topts);
4273	}
4274
4275	static struct dentry *
4276	create_trace_option_core_file(const char *option, long index)
4277	{
4278	struct dentry *t_options;
4279
4280	t_options = trace_options_init_dentry();
4281	if (!t_options)
4282	return NULL;
4283
4284	return trace_create_file(option, 0644, t_options, (void *)index,
4285	&trace_options_core_fops);
4286	}
4287
4288	static __init void create_trace_options_dir(void)
4289	{
4290	struct dentry *t_options;
4291	int i;
4292
4293	t_options = trace_options_init_dentry();
4294	if (!t_options)
4295	return;
4296
4297	for (i = 0; trace_options[i]; i++)
4298	create_trace_option_core_file(trace_options[i], i);
4299	}
4300
4301	static __init int tracer_init_debugfs(void)
4302	{
4303	struct dentry *d_tracer;
4304	int cpu;
4305
4306	trace_access_lock_init();
4307
4308	d_tracer = tracing_init_dentry();
4309
4310	trace_create_file("tracing_enabled", 0644, d_tracer,
4311	&global_trace, &tracing_ctrl_fops);
4312
4313	trace_create_file("trace_options", 0644, d_tracer,
4314	NULL, &tracing_iter_fops);
4315
4316	trace_create_file("tracing_cpumask", 0644, d_tracer,
4317	NULL, &tracing_cpumask_fops);
4318
4319	trace_create_file("trace", 0644, d_tracer,
4320	(void *) TRACE_PIPE_ALL_CPU, &tracing_fops);
4321
4322	trace_create_file("available_tracers", 0444, d_tracer,
4323	&global_trace, &show_traces_fops);
4324
4325	trace_create_file("current_tracer", 0644, d_tracer,
4326	&global_trace, &set_tracer_fops);
4327
4328	#ifdef CONFIG_TRACER_MAX_TRACE
4329	trace_create_file("tracing_max_latency", 0644, d_tracer,
4330	&tracing_max_latency, &tracing_max_lat_fops);
4331	#endif
4332
4333	trace_create_file("tracing_thresh", 0644, d_tracer,
4334	&tracing_thresh, &tracing_max_lat_fops);
4335
4336	trace_create_file("README", 0444, d_tracer,
4337	NULL, &tracing_readme_fops);
4338
4339	trace_create_file("trace_pipe", 0444, d_tracer,
4340	(void *) TRACE_PIPE_ALL_CPU, &tracing_pipe_fops);
4341
4342	trace_create_file("buffer_size_kb", 0644, d_tracer,
4343	&global_trace, &tracing_entries_fops);
4344
4345	trace_create_file("trace_marker", 0220, d_tracer,
4346	NULL, &tracing_mark_fops);
4347
4348	trace_create_file("saved_cmdlines", 0444, d_tracer,
4349	NULL, &tracing_saved_cmdlines_fops);
4350
4351	trace_create_file("trace_clock", 0644, d_tracer, NULL,
4352	&trace_clock_fops);
4353
4354	#ifdef CONFIG_DYNAMIC_FTRACE
4355	trace_create_file("dyn_ftrace_total_info", 0444, d_tracer,
4356	&ftrace_update_tot_cnt, &tracing_dyn_info_fops);
4357	#endif
4358
4359	create_trace_options_dir();
4360
4361	for_each_tracing_cpu(cpu)
4362	tracing_init_debugfs_percpu(cpu);
4363
4364	return 0;
4365	}
4366
4367	static int trace_panic_handler(struct notifier_block *this,
4368	unsigned long event, void *unused)
4369	{
4370	if (ftrace_dump_on_oops)
4371	ftrace_dump(ftrace_dump_on_oops);
4372	return NOTIFY_OK;
4373	}
4374
4375	static struct notifier_block trace_panic_notifier = {
4376	.notifier_call = trace_panic_handler,
4377	.next = NULL,
4378	.priority = 150 /* priority: INT_MAX >= x >= 0 */
4379	};
4380
4381	static int trace_die_handler(struct notifier_block *self,
4382	unsigned long val,
4383	void *data)
4384	{
4385	switch (val) {
4386	case DIE_OOPS:
4387	if (ftrace_dump_on_oops)
4388	ftrace_dump(ftrace_dump_on_oops);
4389	break;
4390	default:
4391	break;
4392	}
4393	return NOTIFY_OK;
4394	}
4395
4396	static struct notifier_block trace_die_notifier = {
4397	.notifier_call = trace_die_handler,
4398	.priority = 200
4399	};
4400
4401	/*
4402	* printk is set to max of 1024, we really don't need it that big.
4403	* Nothing should be printing 1000 characters anyway.
4404	*/
4405	#define TRACE_MAX_PRINT 1000
4406
4407	/*
4408	* Define here KERN_TRACE so that we have one place to modify
4409	* it if we decide to change what log level the ftrace dump
4410	* should be at.
4411	*/
4412	#define KERN_TRACE KERN_EMERG
4413
4414	void
4415	trace_printk_seq(struct trace_seq *s)
4416	{
4417	/* Probably should print a warning here. */
4418	if (s->len >= 1000)
4419	s->len = 1000;
4420
4421	/* should be zero ended, but we are paranoid. */
4422	s->buffer[s->len] = 0;
4423
4424	printk(KERN_TRACE "%s", s->buffer);
4425
4426	trace_seq_init(s);
4427	}
4428
4429	void trace_init_global_iter(struct trace_iterator *iter)
4430	{
4431	iter->tr = &global_trace;
4432	iter->trace = current_trace;
4433	iter->cpu_file = TRACE_PIPE_ALL_CPU;
4434	}
4435
4436	static void
4437	__ftrace_dump(bool disable_tracing, enum ftrace_dump_mode oops_dump_mode)
4438	{
4439	static arch_spinlock_t ftrace_dump_lock =
4440	(arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
4441	/* use static because iter can be a bit big for the stack */
4442	static struct trace_iterator iter;
4443	unsigned int old_userobj;
4444	static int dump_ran;
4445	unsigned long flags;
4446	int cnt = 0, cpu;
4447
4448	/* only one dump */
4449	local_irq_save(flags);
4450	arch_spin_lock(&ftrace_dump_lock);
4451	if (dump_ran)
4452	goto out;
4453
4454	dump_ran = 1;
4455
4456	tracing_off();
4457
4458	if (disable_tracing)
4459	ftrace_kill();
4460
4461	trace_init_global_iter(&iter);
4462
4463	for_each_tracing_cpu(cpu) {
4464	atomic_inc(&iter.tr->data[cpu]->disabled);
4465	}
4466
4467	old_userobj = trace_flags & TRACE_ITER_SYM_USEROBJ;
4468
4469	/* don't look at user memory in panic mode */
4470	trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
4471
4472	/* Simulate the iterator */
4473	iter.tr = &global_trace;
4474	iter.trace = current_trace;
4475
4476	switch (oops_dump_mode) {
4477	case DUMP_ALL:
4478	iter.cpu_file = TRACE_PIPE_ALL_CPU;
4479	break;
4480	case DUMP_ORIG:
4481	iter.cpu_file = raw_smp_processor_id();
4482	break;
4483	case DUMP_NONE:
4484	goto out_enable;
4485	default:
4486	printk(KERN_TRACE "Bad dumping mode, switching to all CPUs dump\n");
4487	iter.cpu_file = TRACE_PIPE_ALL_CPU;
4488	}
4489
4490	printk(KERN_TRACE "Dumping ftrace buffer:\n");
4491
4492	/*
4493	* We need to stop all tracing on all CPUS to read the
4494	* the next buffer. This is a bit expensive, but is
4495	* not done often. We fill all what we can read,
4496	* and then release the locks again.
4497	*/
4498
4499	while (!trace_empty(&iter)) {
4500
4501	if (!cnt)
4502	printk(KERN_TRACE "---------------------------------\n");
4503
4504	cnt++;
4505
4506	/* reset all but tr, trace, and overruns */
4507	memset(&iter.seq, 0,
4508	sizeof(struct trace_iterator) -
4509	offsetof(struct trace_iterator, seq));
4510	iter.iter_flags \|= TRACE_FILE_LAT_FMT;
4511	iter.pos = -1;
4512
4513	if (trace_find_next_entry_inc(&iter) != NULL) {
4514	int ret;
4515
4516	ret = print_trace_line(&iter);
4517	if (ret != TRACE_TYPE_NO_CONSUME)
4518	trace_consume(&iter);
4519	}
4520
4521	trace_printk_seq(&iter.seq);
4522	}
4523
4524	if (!cnt)
4525	printk(KERN_TRACE " (ftrace buffer empty)\n");
4526	else
4527	printk(KERN_TRACE "---------------------------------\n");
4528
4529	out_enable:
4530	/* Re-enable tracing if requested */
4531	if (!disable_tracing) {
4532	trace_flags \|= old_userobj;
4533
4534	for_each_tracing_cpu(cpu) {
4535	atomic_dec(&iter.tr->data[cpu]->disabled);
4536	}
4537	tracing_on();
4538	}
4539
4540	out:
4541	arch_spin_unlock(&ftrace_dump_lock);
4542	local_irq_restore(flags);
4543	}
4544
4545	/* By default: disable tracing after the dump */
4546	void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
4547	{
4548	__ftrace_dump(true, oops_dump_mode);
4549	}
4550
4551	__init static int tracer_alloc_buffers(void)
4552	{
4553	int ring_buf_size;
4554	int i;
4555	int ret = -ENOMEM;
4556
4557	if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
4558	goto out;
4559
4560	if (!alloc_cpumask_var(&tracing_cpumask, GFP_KERNEL))
4561	goto out_free_buffer_mask;
4562
4563	/* To save memory, keep the ring buffer size to its minimum */
4564	if (ring_buffer_expanded)
4565	ring_buf_size = trace_buf_size;
4566	else
4567	ring_buf_size = 1;
4568
4569	cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
4570	cpumask_copy(tracing_cpumask, cpu_all_mask);
4571
4572	/* TODO: make the number of buffers hot pluggable with CPUS */
4573	global_trace.buffer = ring_buffer_alloc(ring_buf_size,
4574	TRACE_BUFFER_FLAGS);
4575	if (!global_trace.buffer) {
4576	printk(KERN_ERR "tracer: failed to allocate ring buffer!\n");
4577	WARN_ON(1);
4578	goto out_free_cpumask;
4579	}
4580	global_trace.entries = ring_buffer_size(global_trace.buffer);
4581
4582
4583	#ifdef CONFIG_TRACER_MAX_TRACE
4584	max_tr.buffer = ring_buffer_alloc(1, TRACE_BUFFER_FLAGS);
4585	if (!max_tr.buffer) {
4586	printk(KERN_ERR "tracer: failed to allocate max ring buffer!\n");
4587	WARN_ON(1);
4588	ring_buffer_free(global_trace.buffer);
4589	goto out_free_cpumask;
4590	}
4591	max_tr.entries = 1;
4592	#endif
4593
4594	/* Allocate the first page for all buffers */
4595	for_each_tracing_cpu(i) {
4596	global_trace.data[i] = &per_cpu(global_trace_cpu, i);
4597	max_tr.data[i] = &per_cpu(max_tr_data, i);
4598	}
4599
4600	trace_init_cmdlines();
4601
4602	register_tracer(&nop_trace);
4603	current_trace = &nop_trace;
4604	/* All seems OK, enable tracing */
4605	tracing_disabled = 0;
4606
4607	atomic_notifier_chain_register(&panic_notifier_list,
4608	&trace_panic_notifier);
4609
4610	register_die_notifier(&trace_die_notifier);
4611
4612	return 0;
4613
4614	out_free_cpumask:
4615	free_cpumask_var(tracing_cpumask);
4616	out_free_buffer_mask:
4617	free_cpumask_var(tracing_buffer_mask);
4618	out:
4619	return ret;
4620	}
4621
4622	__init static int clear_boot_tracer(void)
4623	{
4624	/*
4625	* The default tracer at boot buffer is an init section.
4626	* This function is called in lateinit. If we did not
4627	* find the boot tracer, then clear it out, to prevent
4628	* later registration from accessing the buffer that is
4629	* about to be freed.
4630	*/
4631	if (!default_bootup_tracer)
4632	return 0;
4633
4634	printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n",
4635	default_bootup_tracer);
4636	default_bootup_tracer = NULL;
4637
4638	return 0;
4639	}
4640
4641	early_initcall(tracer_alloc_buffers);
4642	fs_initcall(tracer_init_debugfs);
4643	late_initcall(clear_boot_tracer);