1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * ring buffer based function tracer
4 *
5 * Copyright (C) 2007-2012 Steven Rostedt <srostedt@redhat.com>
6 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
7 *
8 * Originally taken from the RT patch by:
9 * Arnaldo Carvalho de Melo <acme@redhat.com>
10 *
11 * Based on code from the latency_tracer, that is:
12 * Copyright (C) 2004-2006 Ingo Molnar
13 * Copyright (C) 2004 Nadia Yvette Chambers
14 */
15 #include <linux/ring_buffer.h>
16 #include <linux/utsname.h>
17 #include <linux/stacktrace.h>
18 #include <linux/writeback.h>
19 #include <linux/kallsyms.h>
20 #include <linux/security.h>
21 #include <linux/seq_file.h>
22 #include <linux/irqflags.h>
23 #include <linux/debugfs.h>
24 #include <linux/tracefs.h>
25 #include <linux/pagemap.h>
26 #include <linux/hardirq.h>
27 #include <linux/linkage.h>
28 #include <linux/uaccess.h>
29 #include <linux/cleanup.h>
30 #include <linux/vmalloc.h>
31 #include <linux/ftrace.h>
32 #include <linux/module.h>
33 #include <linux/percpu.h>
34 #include <linux/splice.h>
35 #include <linux/kdebug.h>
36 #include <linux/string.h>
37 #include <linux/mount.h>
38 #include <linux/rwsem.h>
39 #include <linux/slab.h>
40 #include <linux/ctype.h>
41 #include <linux/init.h>
42 #include <linux/panic_notifier.h>
43 #include <linux/poll.h>
44 #include <linux/nmi.h>
45 #include <linux/fs.h>
46 #include <linux/trace.h>
47 #include <linux/sched/clock.h>
48 #include <linux/sched/rt.h>
49 #include <linux/fsnotify.h>
50 #include <linux/irq_work.h>
51 #include <linux/workqueue.h>
52
53 #include <asm/setup.h> /* COMMAND_LINE_SIZE */
54
55 #include "trace.h"
56 #include "trace_output.h"
57
58 #ifdef CONFIG_FTRACE_STARTUP_TEST
59 /*
60 * We need to change this state when a selftest is running.
61 * A selftest will lurk into the ring-buffer to count the
62 * entries inserted during the selftest although some concurrent
63 * insertions into the ring-buffer such as trace_printk could occurred
64 * at the same time, giving false positive or negative results.
65 */
66 static bool __read_mostly tracing_selftest_running;
67
68 /*
69 * If boot-time tracing including tracers/events via kernel cmdline
70 * is running, we do not want to run SELFTEST.
71 */
72 bool __read_mostly tracing_selftest_disabled;
73
disable_tracing_selftest(const char * reason)74 void __init disable_tracing_selftest(const char *reason)
75 {
76 if (!tracing_selftest_disabled) {
77 tracing_selftest_disabled = true;
78 pr_info("Ftrace startup test is disabled due to %s\n", reason);
79 }
80 }
81 #else
82 #define tracing_selftest_running 0
83 #define tracing_selftest_disabled 0
84 #endif
85
86 /* Pipe tracepoints to printk */
87 static struct trace_iterator *tracepoint_print_iter;
88 int tracepoint_printk;
89 static bool tracepoint_printk_stop_on_boot __initdata;
90 static DEFINE_STATIC_KEY_FALSE(tracepoint_printk_key);
91
92 /* For tracers that don't implement custom flags */
93 static struct tracer_opt dummy_tracer_opt[] = {
94 { }
95 };
96
97 static int
dummy_set_flag(struct trace_array * tr,u32 old_flags,u32 bit,int set)98 dummy_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
99 {
100 return 0;
101 }
102
103 /*
104 * To prevent the comm cache from being overwritten when no
105 * tracing is active, only save the comm when a trace event
106 * occurred.
107 */
108 DEFINE_PER_CPU(bool, trace_taskinfo_save);
109
110 /*
111 * Kill all tracing for good (never come back).
112 * It is initialized to 1 but will turn to zero if the initialization
113 * of the tracer is successful. But that is the only place that sets
114 * this back to zero.
115 */
116 static int tracing_disabled = 1;
117
118 cpumask_var_t __read_mostly tracing_buffer_mask;
119
120 /*
121 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
122 *
123 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
124 * is set, then ftrace_dump is called. This will output the contents
125 * of the ftrace buffers to the console. This is very useful for
126 * capturing traces that lead to crashes and outputing it to a
127 * serial console.
128 *
129 * It is default off, but you can enable it with either specifying
130 * "ftrace_dump_on_oops" in the kernel command line, or setting
131 * /proc/sys/kernel/ftrace_dump_on_oops
132 * Set 1 if you want to dump buffers of all CPUs
133 * Set 2 if you want to dump the buffer of the CPU that triggered oops
134 * Set instance name if you want to dump the specific trace instance
135 * Multiple instance dump is also supported, and instances are seperated
136 * by commas.
137 */
138 /* Set to string format zero to disable by default */
139 char ftrace_dump_on_oops[MAX_TRACER_SIZE] = "0";
140
141 /* When set, tracing will stop when a WARN*() is hit */
142 int __disable_trace_on_warning;
143
144 #ifdef CONFIG_TRACE_EVAL_MAP_FILE
145 /* Map of enums to their values, for "eval_map" file */
146 struct trace_eval_map_head {
147 struct module *mod;
148 unsigned long length;
149 };
150
151 union trace_eval_map_item;
152
153 struct trace_eval_map_tail {
154 /*
155 * "end" is first and points to NULL as it must be different
156 * than "mod" or "eval_string"
157 */
158 union trace_eval_map_item *next;
159 const char *end; /* points to NULL */
160 };
161
162 static DEFINE_MUTEX(trace_eval_mutex);
163
164 /*
165 * The trace_eval_maps are saved in an array with two extra elements,
166 * one at the beginning, and one at the end. The beginning item contains
167 * the count of the saved maps (head.length), and the module they
168 * belong to if not built in (head.mod). The ending item contains a
169 * pointer to the next array of saved eval_map items.
170 */
171 union trace_eval_map_item {
172 struct trace_eval_map map;
173 struct trace_eval_map_head head;
174 struct trace_eval_map_tail tail;
175 };
176
177 static union trace_eval_map_item *trace_eval_maps;
178 #endif /* CONFIG_TRACE_EVAL_MAP_FILE */
179
180 int tracing_set_tracer(struct trace_array *tr, const char *buf);
181 static void ftrace_trace_userstack(struct trace_array *tr,
182 struct trace_buffer *buffer,
183 unsigned int trace_ctx);
184
185 static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata;
186 static char *default_bootup_tracer;
187
188 static bool allocate_snapshot;
189 static bool snapshot_at_boot;
190
191 static char boot_instance_info[COMMAND_LINE_SIZE] __initdata;
192 static int boot_instance_index;
193
194 static char boot_snapshot_info[COMMAND_LINE_SIZE] __initdata;
195 static int boot_snapshot_index;
196
set_cmdline_ftrace(char * str)197 static int __init set_cmdline_ftrace(char *str)
198 {
199 strscpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
200 default_bootup_tracer = bootup_tracer_buf;
201 /* We are using ftrace early, expand it */
202 trace_set_ring_buffer_expanded(NULL);
203 return 1;
204 }
205 __setup("ftrace=", set_cmdline_ftrace);
206
ftrace_dump_on_oops_enabled(void)207 int ftrace_dump_on_oops_enabled(void)
208 {
209 if (!strcmp("0", ftrace_dump_on_oops))
210 return 0;
211 else
212 return 1;
213 }
214
set_ftrace_dump_on_oops(char * str)215 static int __init set_ftrace_dump_on_oops(char *str)
216 {
217 if (!*str) {
218 strscpy(ftrace_dump_on_oops, "1", MAX_TRACER_SIZE);
219 return 1;
220 }
221
222 if (*str == ',') {
223 strscpy(ftrace_dump_on_oops, "1", MAX_TRACER_SIZE);
224 strscpy(ftrace_dump_on_oops + 1, str, MAX_TRACER_SIZE - 1);
225 return 1;
226 }
227
228 if (*str++ == '=') {
229 strscpy(ftrace_dump_on_oops, str, MAX_TRACER_SIZE);
230 return 1;
231 }
232
233 return 0;
234 }
235 __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
236
stop_trace_on_warning(char * str)237 static int __init stop_trace_on_warning(char *str)
238 {
239 if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
240 __disable_trace_on_warning = 1;
241 return 1;
242 }
243 __setup("traceoff_on_warning", stop_trace_on_warning);
244
boot_alloc_snapshot(char * str)245 static int __init boot_alloc_snapshot(char *str)
246 {
247 char *slot = boot_snapshot_info + boot_snapshot_index;
248 int left = sizeof(boot_snapshot_info) - boot_snapshot_index;
249 int ret;
250
251 if (str[0] == '=') {
252 str++;
253 if (strlen(str) >= left)
254 return -1;
255
256 ret = snprintf(slot, left, "%s\t", str);
257 boot_snapshot_index += ret;
258 } else {
259 allocate_snapshot = true;
260 /* We also need the main ring buffer expanded */
261 trace_set_ring_buffer_expanded(NULL);
262 }
263 return 1;
264 }
265 __setup("alloc_snapshot", boot_alloc_snapshot);
266
267
boot_snapshot(char * str)268 static int __init boot_snapshot(char *str)
269 {
270 snapshot_at_boot = true;
271 boot_alloc_snapshot(str);
272 return 1;
273 }
274 __setup("ftrace_boot_snapshot", boot_snapshot);
275
276
boot_instance(char * str)277 static int __init boot_instance(char *str)
278 {
279 char *slot = boot_instance_info + boot_instance_index;
280 int left = sizeof(boot_instance_info) - boot_instance_index;
281 int ret;
282
283 if (strlen(str) >= left)
284 return -1;
285
286 ret = snprintf(slot, left, "%s\t", str);
287 boot_instance_index += ret;
288
289 return 1;
290 }
291 __setup("trace_instance=", boot_instance);
292
293
294 static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata;
295
set_trace_boot_options(char * str)296 static int __init set_trace_boot_options(char *str)
297 {
298 strscpy(trace_boot_options_buf, str, MAX_TRACER_SIZE);
299 return 1;
300 }
301 __setup("trace_options=", set_trace_boot_options);
302
303 static char trace_boot_clock_buf[MAX_TRACER_SIZE] __initdata;
304 static char *trace_boot_clock __initdata;
305
set_trace_boot_clock(char * str)306 static int __init set_trace_boot_clock(char *str)
307 {
308 strscpy(trace_boot_clock_buf, str, MAX_TRACER_SIZE);
309 trace_boot_clock = trace_boot_clock_buf;
310 return 1;
311 }
312 __setup("trace_clock=", set_trace_boot_clock);
313
set_tracepoint_printk(char * str)314 static int __init set_tracepoint_printk(char *str)
315 {
316 /* Ignore the "tp_printk_stop_on_boot" param */
317 if (*str == '_')
318 return 0;
319
320 if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
321 tracepoint_printk = 1;
322 return 1;
323 }
324 __setup("tp_printk", set_tracepoint_printk);
325
set_tracepoint_printk_stop(char * str)326 static int __init set_tracepoint_printk_stop(char *str)
327 {
328 tracepoint_printk_stop_on_boot = true;
329 return 1;
330 }
331 __setup("tp_printk_stop_on_boot", set_tracepoint_printk_stop);
332
ns2usecs(u64 nsec)333 unsigned long long ns2usecs(u64 nsec)
334 {
335 nsec += 500;
336 do_div(nsec, 1000);
337 return nsec;
338 }
339
340 static void
trace_process_export(struct trace_export * export,struct ring_buffer_event * event,int flag)341 trace_process_export(struct trace_export *export,
342 struct ring_buffer_event *event, int flag)
343 {
344 struct trace_entry *entry;
345 unsigned int size = 0;
346
347 if (export->flags & flag) {
348 entry = ring_buffer_event_data(event);
349 size = ring_buffer_event_length(event);
350 export->write(export, entry, size);
351 }
352 }
353
354 static DEFINE_MUTEX(ftrace_export_lock);
355
356 static struct trace_export __rcu *ftrace_exports_list __read_mostly;
357
358 static DEFINE_STATIC_KEY_FALSE(trace_function_exports_enabled);
359 static DEFINE_STATIC_KEY_FALSE(trace_event_exports_enabled);
360 static DEFINE_STATIC_KEY_FALSE(trace_marker_exports_enabled);
361
ftrace_exports_enable(struct trace_export * export)362 static inline void ftrace_exports_enable(struct trace_export *export)
363 {
364 if (export->flags & TRACE_EXPORT_FUNCTION)
365 static_branch_inc(&trace_function_exports_enabled);
366
367 if (export->flags & TRACE_EXPORT_EVENT)
368 static_branch_inc(&trace_event_exports_enabled);
369
370 if (export->flags & TRACE_EXPORT_MARKER)
371 static_branch_inc(&trace_marker_exports_enabled);
372 }
373
ftrace_exports_disable(struct trace_export * export)374 static inline void ftrace_exports_disable(struct trace_export *export)
375 {
376 if (export->flags & TRACE_EXPORT_FUNCTION)
377 static_branch_dec(&trace_function_exports_enabled);
378
379 if (export->flags & TRACE_EXPORT_EVENT)
380 static_branch_dec(&trace_event_exports_enabled);
381
382 if (export->flags & TRACE_EXPORT_MARKER)
383 static_branch_dec(&trace_marker_exports_enabled);
384 }
385
ftrace_exports(struct ring_buffer_event * event,int flag)386 static void ftrace_exports(struct ring_buffer_event *event, int flag)
387 {
388 struct trace_export *export;
389
390 preempt_disable_notrace();
391
392 export = rcu_dereference_raw_check(ftrace_exports_list);
393 while (export) {
394 trace_process_export(export, event, flag);
395 export = rcu_dereference_raw_check(export->next);
396 }
397
398 preempt_enable_notrace();
399 }
400
401 static inline void
add_trace_export(struct trace_export ** list,struct trace_export * export)402 add_trace_export(struct trace_export **list, struct trace_export *export)
403 {
404 rcu_assign_pointer(export->next, *list);
405 /*
406 * We are entering export into the list but another
407 * CPU might be walking that list. We need to make sure
408 * the export->next pointer is valid before another CPU sees
409 * the export pointer included into the list.
410 */
411 rcu_assign_pointer(*list, export);
412 }
413
414 static inline int
rm_trace_export(struct trace_export ** list,struct trace_export * export)415 rm_trace_export(struct trace_export **list, struct trace_export *export)
416 {
417 struct trace_export **p;
418
419 for (p = list; *p != NULL; p = &(*p)->next)
420 if (*p == export)
421 break;
422
423 if (*p != export)
424 return -1;
425
426 rcu_assign_pointer(*p, (*p)->next);
427
428 return 0;
429 }
430
431 static inline void
add_ftrace_export(struct trace_export ** list,struct trace_export * export)432 add_ftrace_export(struct trace_export **list, struct trace_export *export)
433 {
434 ftrace_exports_enable(export);
435
436 add_trace_export(list, export);
437 }
438
439 static inline int
rm_ftrace_export(struct trace_export ** list,struct trace_export * export)440 rm_ftrace_export(struct trace_export **list, struct trace_export *export)
441 {
442 int ret;
443
444 ret = rm_trace_export(list, export);
445 ftrace_exports_disable(export);
446
447 return ret;
448 }
449
register_ftrace_export(struct trace_export * export)450 int register_ftrace_export(struct trace_export *export)
451 {
452 if (WARN_ON_ONCE(!export->write))
453 return -1;
454
455 mutex_lock(&ftrace_export_lock);
456
457 add_ftrace_export(&ftrace_exports_list, export);
458
459 mutex_unlock(&ftrace_export_lock);
460
461 return 0;
462 }
463 EXPORT_SYMBOL_GPL(register_ftrace_export);
464
unregister_ftrace_export(struct trace_export * export)465 int unregister_ftrace_export(struct trace_export *export)
466 {
467 int ret;
468
469 mutex_lock(&ftrace_export_lock);
470
471 ret = rm_ftrace_export(&ftrace_exports_list, export);
472
473 mutex_unlock(&ftrace_export_lock);
474
475 return ret;
476 }
477 EXPORT_SYMBOL_GPL(unregister_ftrace_export);
478
479 /* trace_flags holds trace_options default values */
480 #define TRACE_DEFAULT_FLAGS \
481 (FUNCTION_DEFAULT_FLAGS | \
482 TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK | \
483 TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | \
484 TRACE_ITER_RECORD_CMD | TRACE_ITER_OVERWRITE | \
485 TRACE_ITER_IRQ_INFO | TRACE_ITER_MARKERS | \
486 TRACE_ITER_HASH_PTR | TRACE_ITER_TRACE_PRINTK)
487
488 /* trace_options that are only supported by global_trace */
489 #define TOP_LEVEL_TRACE_FLAGS (TRACE_ITER_PRINTK | \
490 TRACE_ITER_PRINTK_MSGONLY | TRACE_ITER_RECORD_CMD)
491
492 /* trace_flags that are default zero for instances */
493 #define ZEROED_TRACE_FLAGS \
494 (TRACE_ITER_EVENT_FORK | TRACE_ITER_FUNC_FORK | TRACE_ITER_TRACE_PRINTK)
495
496 /*
497 * The global_trace is the descriptor that holds the top-level tracing
498 * buffers for the live tracing.
499 */
500 static struct trace_array global_trace = {
501 .trace_flags = TRACE_DEFAULT_FLAGS,
502 };
503
504 static struct trace_array *printk_trace = &global_trace;
505
printk_binsafe(struct trace_array * tr)506 static __always_inline bool printk_binsafe(struct trace_array *tr)
507 {
508 /*
509 * The binary format of traceprintk can cause a crash if used
510 * by a buffer from another boot. Force the use of the
511 * non binary version of trace_printk if the trace_printk
512 * buffer is a boot mapped ring buffer.
513 */
514 return !(tr->flags & TRACE_ARRAY_FL_BOOT);
515 }
516
update_printk_trace(struct trace_array * tr)517 static void update_printk_trace(struct trace_array *tr)
518 {
519 if (printk_trace == tr)
520 return;
521
522 printk_trace->trace_flags &= ~TRACE_ITER_TRACE_PRINTK;
523 printk_trace = tr;
524 tr->trace_flags |= TRACE_ITER_TRACE_PRINTK;
525 }
526
trace_set_ring_buffer_expanded(struct trace_array * tr)527 void trace_set_ring_buffer_expanded(struct trace_array *tr)
528 {
529 if (!tr)
530 tr = &global_trace;
531 tr->ring_buffer_expanded = true;
532 }
533
534 LIST_HEAD(ftrace_trace_arrays);
535
trace_array_get(struct trace_array * this_tr)536 int trace_array_get(struct trace_array *this_tr)
537 {
538 struct trace_array *tr;
539
540 guard(mutex)(&trace_types_lock);
541 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
542 if (tr == this_tr) {
543 tr->ref++;
544 return 0;
545 }
546 }
547
548 return -ENODEV;
549 }
550
__trace_array_put(struct trace_array * this_tr)551 static void __trace_array_put(struct trace_array *this_tr)
552 {
553 WARN_ON(!this_tr->ref);
554 this_tr->ref--;
555 }
556
557 /**
558 * trace_array_put - Decrement the reference counter for this trace array.
559 * @this_tr : pointer to the trace array
560 *
561 * NOTE: Use this when we no longer need the trace array returned by
562 * trace_array_get_by_name(). This ensures the trace array can be later
563 * destroyed.
564 *
565 */
trace_array_put(struct trace_array * this_tr)566 void trace_array_put(struct trace_array *this_tr)
567 {
568 if (!this_tr)
569 return;
570
571 mutex_lock(&trace_types_lock);
572 __trace_array_put(this_tr);
573 mutex_unlock(&trace_types_lock);
574 }
575 EXPORT_SYMBOL_GPL(trace_array_put);
576
tracing_check_open_get_tr(struct trace_array * tr)577 int tracing_check_open_get_tr(struct trace_array *tr)
578 {
579 int ret;
580
581 ret = security_locked_down(LOCKDOWN_TRACEFS);
582 if (ret)
583 return ret;
584
585 if (tracing_disabled)
586 return -ENODEV;
587
588 if (tr && trace_array_get(tr) < 0)
589 return -ENODEV;
590
591 return 0;
592 }
593
594 /**
595 * trace_find_filtered_pid - check if a pid exists in a filtered_pid list
596 * @filtered_pids: The list of pids to check
597 * @search_pid: The PID to find in @filtered_pids
598 *
599 * Returns true if @search_pid is found in @filtered_pids, and false otherwise.
600 */
601 bool
trace_find_filtered_pid(struct trace_pid_list * filtered_pids,pid_t search_pid)602 trace_find_filtered_pid(struct trace_pid_list *filtered_pids, pid_t search_pid)
603 {
604 return trace_pid_list_is_set(filtered_pids, search_pid);
605 }
606
607 /**
608 * trace_ignore_this_task - should a task be ignored for tracing
609 * @filtered_pids: The list of pids to check
610 * @filtered_no_pids: The list of pids not to be traced
611 * @task: The task that should be ignored if not filtered
612 *
613 * Checks if @task should be traced or not from @filtered_pids.
614 * Returns true if @task should *NOT* be traced.
615 * Returns false if @task should be traced.
616 */
617 bool
trace_ignore_this_task(struct trace_pid_list * filtered_pids,struct trace_pid_list * filtered_no_pids,struct task_struct * task)618 trace_ignore_this_task(struct trace_pid_list *filtered_pids,
619 struct trace_pid_list *filtered_no_pids,
620 struct task_struct *task)
621 {
622 /*
623 * If filtered_no_pids is not empty, and the task's pid is listed
624 * in filtered_no_pids, then return true.
625 * Otherwise, if filtered_pids is empty, that means we can
626 * trace all tasks. If it has content, then only trace pids
627 * within filtered_pids.
628 */
629
630 return (filtered_pids &&
631 !trace_find_filtered_pid(filtered_pids, task->pid)) ||
632 (filtered_no_pids &&
633 trace_find_filtered_pid(filtered_no_pids, task->pid));
634 }
635
636 /**
637 * trace_filter_add_remove_task - Add or remove a task from a pid_list
638 * @pid_list: The list to modify
639 * @self: The current task for fork or NULL for exit
640 * @task: The task to add or remove
641 *
642 * If adding a task, if @self is defined, the task is only added if @self
643 * is also included in @pid_list. This happens on fork and tasks should
644 * only be added when the parent is listed. If @self is NULL, then the
645 * @task pid will be removed from the list, which would happen on exit
646 * of a task.
647 */
trace_filter_add_remove_task(struct trace_pid_list * pid_list,struct task_struct * self,struct task_struct * task)648 void trace_filter_add_remove_task(struct trace_pid_list *pid_list,
649 struct task_struct *self,
650 struct task_struct *task)
651 {
652 if (!pid_list)
653 return;
654
655 /* For forks, we only add if the forking task is listed */
656 if (self) {
657 if (!trace_find_filtered_pid(pid_list, self->pid))
658 return;
659 }
660
661 /* "self" is set for forks, and NULL for exits */
662 if (self)
663 trace_pid_list_set(pid_list, task->pid);
664 else
665 trace_pid_list_clear(pid_list, task->pid);
666 }
667
668 /**
669 * trace_pid_next - Used for seq_file to get to the next pid of a pid_list
670 * @pid_list: The pid list to show
671 * @v: The last pid that was shown (+1 the actual pid to let zero be displayed)
672 * @pos: The position of the file
673 *
674 * This is used by the seq_file "next" operation to iterate the pids
675 * listed in a trace_pid_list structure.
676 *
677 * Returns the pid+1 as we want to display pid of zero, but NULL would
678 * stop the iteration.
679 */
trace_pid_next(struct trace_pid_list * pid_list,void * v,loff_t * pos)680 void *trace_pid_next(struct trace_pid_list *pid_list, void *v, loff_t *pos)
681 {
682 long pid = (unsigned long)v;
683 unsigned int next;
684
685 (*pos)++;
686
687 /* pid already is +1 of the actual previous bit */
688 if (trace_pid_list_next(pid_list, pid, &next) < 0)
689 return NULL;
690
691 pid = next;
692
693 /* Return pid + 1 to allow zero to be represented */
694 return (void *)(pid + 1);
695 }
696
697 /**
698 * trace_pid_start - Used for seq_file to start reading pid lists
699 * @pid_list: The pid list to show
700 * @pos: The position of the file
701 *
702 * This is used by seq_file "start" operation to start the iteration
703 * of listing pids.
704 *
705 * Returns the pid+1 as we want to display pid of zero, but NULL would
706 * stop the iteration.
707 */
trace_pid_start(struct trace_pid_list * pid_list,loff_t * pos)708 void *trace_pid_start(struct trace_pid_list *pid_list, loff_t *pos)
709 {
710 unsigned long pid;
711 unsigned int first;
712 loff_t l = 0;
713
714 if (trace_pid_list_first(pid_list, &first) < 0)
715 return NULL;
716
717 pid = first;
718
719 /* Return pid + 1 so that zero can be the exit value */
720 for (pid++; pid && l < *pos;
721 pid = (unsigned long)trace_pid_next(pid_list, (void *)pid, &l))
722 ;
723 return (void *)pid;
724 }
725
726 /**
727 * trace_pid_show - show the current pid in seq_file processing
728 * @m: The seq_file structure to write into
729 * @v: A void pointer of the pid (+1) value to display
730 *
731 * Can be directly used by seq_file operations to display the current
732 * pid value.
733 */
trace_pid_show(struct seq_file * m,void * v)734 int trace_pid_show(struct seq_file *m, void *v)
735 {
736 unsigned long pid = (unsigned long)v - 1;
737
738 seq_printf(m, "%lu\n", pid);
739 return 0;
740 }
741
742 /* 128 should be much more than enough */
743 #define PID_BUF_SIZE 127
744
trace_pid_write(struct trace_pid_list * filtered_pids,struct trace_pid_list ** new_pid_list,const char __user * ubuf,size_t cnt)745 int trace_pid_write(struct trace_pid_list *filtered_pids,
746 struct trace_pid_list **new_pid_list,
747 const char __user *ubuf, size_t cnt)
748 {
749 struct trace_pid_list *pid_list;
750 struct trace_parser parser;
751 unsigned long val;
752 int nr_pids = 0;
753 ssize_t read = 0;
754 ssize_t ret;
755 loff_t pos;
756 pid_t pid;
757
758 if (trace_parser_get_init(&parser, PID_BUF_SIZE + 1))
759 return -ENOMEM;
760
761 /*
762 * Always recreate a new array. The write is an all or nothing
763 * operation. Always create a new array when adding new pids by
764 * the user. If the operation fails, then the current list is
765 * not modified.
766 */
767 pid_list = trace_pid_list_alloc();
768 if (!pid_list) {
769 trace_parser_put(&parser);
770 return -ENOMEM;
771 }
772
773 if (filtered_pids) {
774 /* copy the current bits to the new max */
775 ret = trace_pid_list_first(filtered_pids, &pid);
776 while (!ret) {
777 trace_pid_list_set(pid_list, pid);
778 ret = trace_pid_list_next(filtered_pids, pid + 1, &pid);
779 nr_pids++;
780 }
781 }
782
783 ret = 0;
784 while (cnt > 0) {
785
786 pos = 0;
787
788 ret = trace_get_user(&parser, ubuf, cnt, &pos);
789 if (ret < 0)
790 break;
791
792 read += ret;
793 ubuf += ret;
794 cnt -= ret;
795
796 if (!trace_parser_loaded(&parser))
797 break;
798
799 ret = -EINVAL;
800 if (kstrtoul(parser.buffer, 0, &val))
801 break;
802
803 pid = (pid_t)val;
804
805 if (trace_pid_list_set(pid_list, pid) < 0) {
806 ret = -1;
807 break;
808 }
809 nr_pids++;
810
811 trace_parser_clear(&parser);
812 ret = 0;
813 }
814 trace_parser_put(&parser);
815
816 if (ret < 0) {
817 trace_pid_list_free(pid_list);
818 return ret;
819 }
820
821 if (!nr_pids) {
822 /* Cleared the list of pids */
823 trace_pid_list_free(pid_list);
824 pid_list = NULL;
825 }
826
827 *new_pid_list = pid_list;
828
829 return read;
830 }
831
buffer_ftrace_now(struct array_buffer * buf,int cpu)832 static u64 buffer_ftrace_now(struct array_buffer *buf, int cpu)
833 {
834 u64 ts;
835
836 /* Early boot up does not have a buffer yet */
837 if (!buf->buffer)
838 return trace_clock_local();
839
840 ts = ring_buffer_time_stamp(buf->buffer);
841 ring_buffer_normalize_time_stamp(buf->buffer, cpu, &ts);
842
843 return ts;
844 }
845
ftrace_now(int cpu)846 u64 ftrace_now(int cpu)
847 {
848 return buffer_ftrace_now(&global_trace.array_buffer, cpu);
849 }
850
851 /**
852 * tracing_is_enabled - Show if global_trace has been enabled
853 *
854 * Shows if the global trace has been enabled or not. It uses the
855 * mirror flag "buffer_disabled" to be used in fast paths such as for
856 * the irqsoff tracer. But it may be inaccurate due to races. If you
857 * need to know the accurate state, use tracing_is_on() which is a little
858 * slower, but accurate.
859 */
tracing_is_enabled(void)860 int tracing_is_enabled(void)
861 {
862 /*
863 * For quick access (irqsoff uses this in fast path), just
864 * return the mirror variable of the state of the ring buffer.
865 * It's a little racy, but we don't really care.
866 */
867 smp_rmb();
868 return !global_trace.buffer_disabled;
869 }
870
871 /*
872 * trace_buf_size is the size in bytes that is allocated
873 * for a buffer. Note, the number of bytes is always rounded
874 * to page size.
875 *
876 * This number is purposely set to a low number of 16384.
877 * If the dump on oops happens, it will be much appreciated
878 * to not have to wait for all that output. Anyway this can be
879 * boot time and run time configurable.
880 */
881 #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
882
883 static unsigned long trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
884
885 /* trace_types holds a link list of available tracers. */
886 static struct tracer *trace_types __read_mostly;
887
888 /*
889 * trace_types_lock is used to protect the trace_types list.
890 */
891 DEFINE_MUTEX(trace_types_lock);
892
893 /*
894 * serialize the access of the ring buffer
895 *
896 * ring buffer serializes readers, but it is low level protection.
897 * The validity of the events (which returns by ring_buffer_peek() ..etc)
898 * are not protected by ring buffer.
899 *
900 * The content of events may become garbage if we allow other process consumes
901 * these events concurrently:
902 * A) the page of the consumed events may become a normal page
903 * (not reader page) in ring buffer, and this page will be rewritten
904 * by events producer.
905 * B) The page of the consumed events may become a page for splice_read,
906 * and this page will be returned to system.
907 *
908 * These primitives allow multi process access to different cpu ring buffer
909 * concurrently.
910 *
911 * These primitives don't distinguish read-only and read-consume access.
912 * Multi read-only access are also serialized.
913 */
914
915 #ifdef CONFIG_SMP
916 static DECLARE_RWSEM(all_cpu_access_lock);
917 static DEFINE_PER_CPU(struct mutex, cpu_access_lock);
918
trace_access_lock(int cpu)919 static inline void trace_access_lock(int cpu)
920 {
921 if (cpu == RING_BUFFER_ALL_CPUS) {
922 /* gain it for accessing the whole ring buffer. */
923 down_write(&all_cpu_access_lock);
924 } else {
925 /* gain it for accessing a cpu ring buffer. */
926
927 /* Firstly block other trace_access_lock(RING_BUFFER_ALL_CPUS). */
928 down_read(&all_cpu_access_lock);
929
930 /* Secondly block other access to this @cpu ring buffer. */
931 mutex_lock(&per_cpu(cpu_access_lock, cpu));
932 }
933 }
934
trace_access_unlock(int cpu)935 static inline void trace_access_unlock(int cpu)
936 {
937 if (cpu == RING_BUFFER_ALL_CPUS) {
938 up_write(&all_cpu_access_lock);
939 } else {
940 mutex_unlock(&per_cpu(cpu_access_lock, cpu));
941 up_read(&all_cpu_access_lock);
942 }
943 }
944
trace_access_lock_init(void)945 static inline void trace_access_lock_init(void)
946 {
947 int cpu;
948
949 for_each_possible_cpu(cpu)
950 mutex_init(&per_cpu(cpu_access_lock, cpu));
951 }
952
953 #else
954
955 static DEFINE_MUTEX(access_lock);
956
trace_access_lock(int cpu)957 static inline void trace_access_lock(int cpu)
958 {
959 (void)cpu;
960 mutex_lock(&access_lock);
961 }
962
trace_access_unlock(int cpu)963 static inline void trace_access_unlock(int cpu)
964 {
965 (void)cpu;
966 mutex_unlock(&access_lock);
967 }
968
trace_access_lock_init(void)969 static inline void trace_access_lock_init(void)
970 {
971 }
972
973 #endif
974
975 #ifdef CONFIG_STACKTRACE
976 static void __ftrace_trace_stack(struct trace_array *tr,
977 struct trace_buffer *buffer,
978 unsigned int trace_ctx,
979 int skip, struct pt_regs *regs);
980 static inline void ftrace_trace_stack(struct trace_array *tr,
981 struct trace_buffer *buffer,
982 unsigned int trace_ctx,
983 int skip, struct pt_regs *regs);
984
985 #else
__ftrace_trace_stack(struct trace_array * tr,struct trace_buffer * buffer,unsigned int trace_ctx,int skip,struct pt_regs * regs)986 static inline void __ftrace_trace_stack(struct trace_array *tr,
987 struct trace_buffer *buffer,
988 unsigned int trace_ctx,
989 int skip, struct pt_regs *regs)
990 {
991 }
ftrace_trace_stack(struct trace_array * tr,struct trace_buffer * buffer,unsigned long trace_ctx,int skip,struct pt_regs * regs)992 static inline void ftrace_trace_stack(struct trace_array *tr,
993 struct trace_buffer *buffer,
994 unsigned long trace_ctx,
995 int skip, struct pt_regs *regs)
996 {
997 }
998
999 #endif
1000
1001 static __always_inline void
trace_event_setup(struct ring_buffer_event * event,int type,unsigned int trace_ctx)1002 trace_event_setup(struct ring_buffer_event *event,
1003 int type, unsigned int trace_ctx)
1004 {
1005 struct trace_entry *ent = ring_buffer_event_data(event);
1006
1007 tracing_generic_entry_update(ent, type, trace_ctx);
1008 }
1009
1010 static __always_inline struct ring_buffer_event *
__trace_buffer_lock_reserve(struct trace_buffer * buffer,int type,unsigned long len,unsigned int trace_ctx)1011 __trace_buffer_lock_reserve(struct trace_buffer *buffer,
1012 int type,
1013 unsigned long len,
1014 unsigned int trace_ctx)
1015 {
1016 struct ring_buffer_event *event;
1017
1018 event = ring_buffer_lock_reserve(buffer, len);
1019 if (event != NULL)
1020 trace_event_setup(event, type, trace_ctx);
1021
1022 return event;
1023 }
1024
tracer_tracing_on(struct trace_array * tr)1025 void tracer_tracing_on(struct trace_array *tr)
1026 {
1027 if (tr->array_buffer.buffer)
1028 ring_buffer_record_on(tr->array_buffer.buffer);
1029 /*
1030 * This flag is looked at when buffers haven't been allocated
1031 * yet, or by some tracers (like irqsoff), that just want to
1032 * know if the ring buffer has been disabled, but it can handle
1033 * races of where it gets disabled but we still do a record.
1034 * As the check is in the fast path of the tracers, it is more
1035 * important to be fast than accurate.
1036 */
1037 tr->buffer_disabled = 0;
1038 /* Make the flag seen by readers */
1039 smp_wmb();
1040 }
1041
1042 /**
1043 * tracing_on - enable tracing buffers
1044 *
1045 * This function enables tracing buffers that may have been
1046 * disabled with tracing_off.
1047 */
tracing_on(void)1048 void tracing_on(void)
1049 {
1050 tracer_tracing_on(&global_trace);
1051 }
1052 EXPORT_SYMBOL_GPL(tracing_on);
1053
1054
1055 static __always_inline void
__buffer_unlock_commit(struct trace_buffer * buffer,struct ring_buffer_event * event)1056 __buffer_unlock_commit(struct trace_buffer *buffer, struct ring_buffer_event *event)
1057 {
1058 __this_cpu_write(trace_taskinfo_save, true);
1059
1060 /* If this is the temp buffer, we need to commit fully */
1061 if (this_cpu_read(trace_buffered_event) == event) {
1062 /* Length is in event->array[0] */
1063 ring_buffer_write(buffer, event->array[0], &event->array[1]);
1064 /* Release the temp buffer */
1065 this_cpu_dec(trace_buffered_event_cnt);
1066 /* ring_buffer_unlock_commit() enables preemption */
1067 preempt_enable_notrace();
1068 } else
1069 ring_buffer_unlock_commit(buffer);
1070 }
1071
__trace_array_puts(struct trace_array * tr,unsigned long ip,const char * str,int size)1072 int __trace_array_puts(struct trace_array *tr, unsigned long ip,
1073 const char *str, int size)
1074 {
1075 struct ring_buffer_event *event;
1076 struct trace_buffer *buffer;
1077 struct print_entry *entry;
1078 unsigned int trace_ctx;
1079 int alloc;
1080
1081 if (!(tr->trace_flags & TRACE_ITER_PRINTK))
1082 return 0;
1083
1084 if (unlikely(tracing_selftest_running && tr == &global_trace))
1085 return 0;
1086
1087 if (unlikely(tracing_disabled))
1088 return 0;
1089
1090 alloc = sizeof(*entry) + size + 2; /* possible \n added */
1091
1092 trace_ctx = tracing_gen_ctx();
1093 buffer = tr->array_buffer.buffer;
1094 ring_buffer_nest_start(buffer);
1095 event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc,
1096 trace_ctx);
1097 if (!event) {
1098 size = 0;
1099 goto out;
1100 }
1101
1102 entry = ring_buffer_event_data(event);
1103 entry->ip = ip;
1104
1105 memcpy(&entry->buf, str, size);
1106
1107 /* Add a newline if necessary */
1108 if (entry->buf[size - 1] != '\n') {
1109 entry->buf[size] = '\n';
1110 entry->buf[size + 1] = '\0';
1111 } else
1112 entry->buf[size] = '\0';
1113
1114 __buffer_unlock_commit(buffer, event);
1115 ftrace_trace_stack(tr, buffer, trace_ctx, 4, NULL);
1116 out:
1117 ring_buffer_nest_end(buffer);
1118 return size;
1119 }
1120 EXPORT_SYMBOL_GPL(__trace_array_puts);
1121
1122 /**
1123 * __trace_puts - write a constant string into the trace buffer.
1124 * @ip: The address of the caller
1125 * @str: The constant string to write
1126 * @size: The size of the string.
1127 */
__trace_puts(unsigned long ip,const char * str,int size)1128 int __trace_puts(unsigned long ip, const char *str, int size)
1129 {
1130 return __trace_array_puts(printk_trace, ip, str, size);
1131 }
1132 EXPORT_SYMBOL_GPL(__trace_puts);
1133
1134 /**
1135 * __trace_bputs - write the pointer to a constant string into trace buffer
1136 * @ip: The address of the caller
1137 * @str: The constant string to write to the buffer to
1138 */
__trace_bputs(unsigned long ip,const char * str)1139 int __trace_bputs(unsigned long ip, const char *str)
1140 {
1141 struct trace_array *tr = READ_ONCE(printk_trace);
1142 struct ring_buffer_event *event;
1143 struct trace_buffer *buffer;
1144 struct bputs_entry *entry;
1145 unsigned int trace_ctx;
1146 int size = sizeof(struct bputs_entry);
1147 int ret = 0;
1148
1149 if (!printk_binsafe(tr))
1150 return __trace_puts(ip, str, strlen(str));
1151
1152 if (!(tr->trace_flags & TRACE_ITER_PRINTK))
1153 return 0;
1154
1155 if (unlikely(tracing_selftest_running || tracing_disabled))
1156 return 0;
1157
1158 trace_ctx = tracing_gen_ctx();
1159 buffer = tr->array_buffer.buffer;
1160
1161 ring_buffer_nest_start(buffer);
1162 event = __trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size,
1163 trace_ctx);
1164 if (!event)
1165 goto out;
1166
1167 entry = ring_buffer_event_data(event);
1168 entry->ip = ip;
1169 entry->str = str;
1170
1171 __buffer_unlock_commit(buffer, event);
1172 ftrace_trace_stack(tr, buffer, trace_ctx, 4, NULL);
1173
1174 ret = 1;
1175 out:
1176 ring_buffer_nest_end(buffer);
1177 return ret;
1178 }
1179 EXPORT_SYMBOL_GPL(__trace_bputs);
1180
1181 #ifdef CONFIG_TRACER_SNAPSHOT
tracing_snapshot_instance_cond(struct trace_array * tr,void * cond_data)1182 static void tracing_snapshot_instance_cond(struct trace_array *tr,
1183 void *cond_data)
1184 {
1185 struct tracer *tracer = tr->current_trace;
1186 unsigned long flags;
1187
1188 if (in_nmi()) {
1189 trace_array_puts(tr, "*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n");
1190 trace_array_puts(tr, "*** snapshot is being ignored ***\n");
1191 return;
1192 }
1193
1194 if (!tr->allocated_snapshot) {
1195 trace_array_puts(tr, "*** SNAPSHOT NOT ALLOCATED ***\n");
1196 trace_array_puts(tr, "*** stopping trace here! ***\n");
1197 tracer_tracing_off(tr);
1198 return;
1199 }
1200
1201 /* Note, snapshot can not be used when the tracer uses it */
1202 if (tracer->use_max_tr) {
1203 trace_array_puts(tr, "*** LATENCY TRACER ACTIVE ***\n");
1204 trace_array_puts(tr, "*** Can not use snapshot (sorry) ***\n");
1205 return;
1206 }
1207
1208 if (tr->mapped) {
1209 trace_array_puts(tr, "*** BUFFER MEMORY MAPPED ***\n");
1210 trace_array_puts(tr, "*** Can not use snapshot (sorry) ***\n");
1211 return;
1212 }
1213
1214 local_irq_save(flags);
1215 update_max_tr(tr, current, smp_processor_id(), cond_data);
1216 local_irq_restore(flags);
1217 }
1218
tracing_snapshot_instance(struct trace_array * tr)1219 void tracing_snapshot_instance(struct trace_array *tr)
1220 {
1221 tracing_snapshot_instance_cond(tr, NULL);
1222 }
1223
1224 /**
1225 * tracing_snapshot - take a snapshot of the current buffer.
1226 *
1227 * This causes a swap between the snapshot buffer and the current live
1228 * tracing buffer. You can use this to take snapshots of the live
1229 * trace when some condition is triggered, but continue to trace.
1230 *
1231 * Note, make sure to allocate the snapshot with either
1232 * a tracing_snapshot_alloc(), or by doing it manually
1233 * with: echo 1 > /sys/kernel/tracing/snapshot
1234 *
1235 * If the snapshot buffer is not allocated, it will stop tracing.
1236 * Basically making a permanent snapshot.
1237 */
tracing_snapshot(void)1238 void tracing_snapshot(void)
1239 {
1240 struct trace_array *tr = &global_trace;
1241
1242 tracing_snapshot_instance(tr);
1243 }
1244 EXPORT_SYMBOL_GPL(tracing_snapshot);
1245
1246 /**
1247 * tracing_snapshot_cond - conditionally take a snapshot of the current buffer.
1248 * @tr: The tracing instance to snapshot
1249 * @cond_data: The data to be tested conditionally, and possibly saved
1250 *
1251 * This is the same as tracing_snapshot() except that the snapshot is
1252 * conditional - the snapshot will only happen if the
1253 * cond_snapshot.update() implementation receiving the cond_data
1254 * returns true, which means that the trace array's cond_snapshot
1255 * update() operation used the cond_data to determine whether the
1256 * snapshot should be taken, and if it was, presumably saved it along
1257 * with the snapshot.
1258 */
tracing_snapshot_cond(struct trace_array * tr,void * cond_data)1259 void tracing_snapshot_cond(struct trace_array *tr, void *cond_data)
1260 {
1261 tracing_snapshot_instance_cond(tr, cond_data);
1262 }
1263 EXPORT_SYMBOL_GPL(tracing_snapshot_cond);
1264
1265 /**
1266 * tracing_cond_snapshot_data - get the user data associated with a snapshot
1267 * @tr: The tracing instance
1268 *
1269 * When the user enables a conditional snapshot using
1270 * tracing_snapshot_cond_enable(), the user-defined cond_data is saved
1271 * with the snapshot. This accessor is used to retrieve it.
1272 *
1273 * Should not be called from cond_snapshot.update(), since it takes
1274 * the tr->max_lock lock, which the code calling
1275 * cond_snapshot.update() has already done.
1276 *
1277 * Returns the cond_data associated with the trace array's snapshot.
1278 */
tracing_cond_snapshot_data(struct trace_array * tr)1279 void *tracing_cond_snapshot_data(struct trace_array *tr)
1280 {
1281 void *cond_data = NULL;
1282
1283 local_irq_disable();
1284 arch_spin_lock(&tr->max_lock);
1285
1286 if (tr->cond_snapshot)
1287 cond_data = tr->cond_snapshot->cond_data;
1288
1289 arch_spin_unlock(&tr->max_lock);
1290 local_irq_enable();
1291
1292 return cond_data;
1293 }
1294 EXPORT_SYMBOL_GPL(tracing_cond_snapshot_data);
1295
1296 static int resize_buffer_duplicate_size(struct array_buffer *trace_buf,
1297 struct array_buffer *size_buf, int cpu_id);
1298 static void set_buffer_entries(struct array_buffer *buf, unsigned long val);
1299
tracing_alloc_snapshot_instance(struct trace_array * tr)1300 int tracing_alloc_snapshot_instance(struct trace_array *tr)
1301 {
1302 int order;
1303 int ret;
1304
1305 if (!tr->allocated_snapshot) {
1306
1307 /* Make the snapshot buffer have the same order as main buffer */
1308 order = ring_buffer_subbuf_order_get(tr->array_buffer.buffer);
1309 ret = ring_buffer_subbuf_order_set(tr->max_buffer.buffer, order);
1310 if (ret < 0)
1311 return ret;
1312
1313 /* allocate spare buffer */
1314 ret = resize_buffer_duplicate_size(&tr->max_buffer,
1315 &tr->array_buffer, RING_BUFFER_ALL_CPUS);
1316 if (ret < 0)
1317 return ret;
1318
1319 tr->allocated_snapshot = true;
1320 }
1321
1322 return 0;
1323 }
1324
free_snapshot(struct trace_array * tr)1325 static void free_snapshot(struct trace_array *tr)
1326 {
1327 /*
1328 * We don't free the ring buffer. instead, resize it because
1329 * The max_tr ring buffer has some state (e.g. ring->clock) and
1330 * we want preserve it.
1331 */
1332 ring_buffer_subbuf_order_set(tr->max_buffer.buffer, 0);
1333 ring_buffer_resize(tr->max_buffer.buffer, 1, RING_BUFFER_ALL_CPUS);
1334 set_buffer_entries(&tr->max_buffer, 1);
1335 tracing_reset_online_cpus(&tr->max_buffer);
1336 tr->allocated_snapshot = false;
1337 }
1338
tracing_arm_snapshot_locked(struct trace_array * tr)1339 static int tracing_arm_snapshot_locked(struct trace_array *tr)
1340 {
1341 int ret;
1342
1343 lockdep_assert_held(&trace_types_lock);
1344
1345 spin_lock(&tr->snapshot_trigger_lock);
1346 if (tr->snapshot == UINT_MAX || tr->mapped) {
1347 spin_unlock(&tr->snapshot_trigger_lock);
1348 return -EBUSY;
1349 }
1350
1351 tr->snapshot++;
1352 spin_unlock(&tr->snapshot_trigger_lock);
1353
1354 ret = tracing_alloc_snapshot_instance(tr);
1355 if (ret) {
1356 spin_lock(&tr->snapshot_trigger_lock);
1357 tr->snapshot--;
1358 spin_unlock(&tr->snapshot_trigger_lock);
1359 }
1360
1361 return ret;
1362 }
1363
tracing_arm_snapshot(struct trace_array * tr)1364 int tracing_arm_snapshot(struct trace_array *tr)
1365 {
1366 int ret;
1367
1368 mutex_lock(&trace_types_lock);
1369 ret = tracing_arm_snapshot_locked(tr);
1370 mutex_unlock(&trace_types_lock);
1371
1372 return ret;
1373 }
1374
tracing_disarm_snapshot(struct trace_array * tr)1375 void tracing_disarm_snapshot(struct trace_array *tr)
1376 {
1377 spin_lock(&tr->snapshot_trigger_lock);
1378 if (!WARN_ON(!tr->snapshot))
1379 tr->snapshot--;
1380 spin_unlock(&tr->snapshot_trigger_lock);
1381 }
1382
1383 /**
1384 * tracing_alloc_snapshot - allocate snapshot buffer.
1385 *
1386 * This only allocates the snapshot buffer if it isn't already
1387 * allocated - it doesn't also take a snapshot.
1388 *
1389 * This is meant to be used in cases where the snapshot buffer needs
1390 * to be set up for events that can't sleep but need to be able to
1391 * trigger a snapshot.
1392 */
tracing_alloc_snapshot(void)1393 int tracing_alloc_snapshot(void)
1394 {
1395 struct trace_array *tr = &global_trace;
1396 int ret;
1397
1398 ret = tracing_alloc_snapshot_instance(tr);
1399 WARN_ON(ret < 0);
1400
1401 return ret;
1402 }
1403 EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
1404
1405 /**
1406 * tracing_snapshot_alloc - allocate and take a snapshot of the current buffer.
1407 *
1408 * This is similar to tracing_snapshot(), but it will allocate the
1409 * snapshot buffer if it isn't already allocated. Use this only
1410 * where it is safe to sleep, as the allocation may sleep.
1411 *
1412 * This causes a swap between the snapshot buffer and the current live
1413 * tracing buffer. You can use this to take snapshots of the live
1414 * trace when some condition is triggered, but continue to trace.
1415 */
tracing_snapshot_alloc(void)1416 void tracing_snapshot_alloc(void)
1417 {
1418 int ret;
1419
1420 ret = tracing_alloc_snapshot();
1421 if (ret < 0)
1422 return;
1423
1424 tracing_snapshot();
1425 }
1426 EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
1427
1428 /**
1429 * tracing_snapshot_cond_enable - enable conditional snapshot for an instance
1430 * @tr: The tracing instance
1431 * @cond_data: User data to associate with the snapshot
1432 * @update: Implementation of the cond_snapshot update function
1433 *
1434 * Check whether the conditional snapshot for the given instance has
1435 * already been enabled, or if the current tracer is already using a
1436 * snapshot; if so, return -EBUSY, else create a cond_snapshot and
1437 * save the cond_data and update function inside.
1438 *
1439 * Returns 0 if successful, error otherwise.
1440 */
tracing_snapshot_cond_enable(struct trace_array * tr,void * cond_data,cond_update_fn_t update)1441 int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data,
1442 cond_update_fn_t update)
1443 {
1444 struct cond_snapshot *cond_snapshot __free(kfree) =
1445 kzalloc(sizeof(*cond_snapshot), GFP_KERNEL);
1446 int ret;
1447
1448 if (!cond_snapshot)
1449 return -ENOMEM;
1450
1451 cond_snapshot->cond_data = cond_data;
1452 cond_snapshot->update = update;
1453
1454 guard(mutex)(&trace_types_lock);
1455
1456 if (tr->current_trace->use_max_tr)
1457 return -EBUSY;
1458
1459 /*
1460 * The cond_snapshot can only change to NULL without the
1461 * trace_types_lock. We don't care if we race with it going
1462 * to NULL, but we want to make sure that it's not set to
1463 * something other than NULL when we get here, which we can
1464 * do safely with only holding the trace_types_lock and not
1465 * having to take the max_lock.
1466 */
1467 if (tr->cond_snapshot)
1468 return -EBUSY;
1469
1470 ret = tracing_arm_snapshot_locked(tr);
1471 if (ret)
1472 return ret;
1473
1474 local_irq_disable();
1475 arch_spin_lock(&tr->max_lock);
1476 tr->cond_snapshot = no_free_ptr(cond_snapshot);
1477 arch_spin_unlock(&tr->max_lock);
1478 local_irq_enable();
1479
1480 return 0;
1481 }
1482 EXPORT_SYMBOL_GPL(tracing_snapshot_cond_enable);
1483
1484 /**
1485 * tracing_snapshot_cond_disable - disable conditional snapshot for an instance
1486 * @tr: The tracing instance
1487 *
1488 * Check whether the conditional snapshot for the given instance is
1489 * enabled; if so, free the cond_snapshot associated with it,
1490 * otherwise return -EINVAL.
1491 *
1492 * Returns 0 if successful, error otherwise.
1493 */
tracing_snapshot_cond_disable(struct trace_array * tr)1494 int tracing_snapshot_cond_disable(struct trace_array *tr)
1495 {
1496 int ret = 0;
1497
1498 local_irq_disable();
1499 arch_spin_lock(&tr->max_lock);
1500
1501 if (!tr->cond_snapshot)
1502 ret = -EINVAL;
1503 else {
1504 kfree(tr->cond_snapshot);
1505 tr->cond_snapshot = NULL;
1506 }
1507
1508 arch_spin_unlock(&tr->max_lock);
1509 local_irq_enable();
1510
1511 tracing_disarm_snapshot(tr);
1512
1513 return ret;
1514 }
1515 EXPORT_SYMBOL_GPL(tracing_snapshot_cond_disable);
1516 #else
tracing_snapshot(void)1517 void tracing_snapshot(void)
1518 {
1519 WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used");
1520 }
1521 EXPORT_SYMBOL_GPL(tracing_snapshot);
tracing_snapshot_cond(struct trace_array * tr,void * cond_data)1522 void tracing_snapshot_cond(struct trace_array *tr, void *cond_data)
1523 {
1524 WARN_ONCE(1, "Snapshot feature not enabled, but internal conditional snapshot used");
1525 }
1526 EXPORT_SYMBOL_GPL(tracing_snapshot_cond);
tracing_alloc_snapshot(void)1527 int tracing_alloc_snapshot(void)
1528 {
1529 WARN_ONCE(1, "Snapshot feature not enabled, but snapshot allocation used");
1530 return -ENODEV;
1531 }
1532 EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
tracing_snapshot_alloc(void)1533 void tracing_snapshot_alloc(void)
1534 {
1535 /* Give warning */
1536 tracing_snapshot();
1537 }
1538 EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
tracing_cond_snapshot_data(struct trace_array * tr)1539 void *tracing_cond_snapshot_data(struct trace_array *tr)
1540 {
1541 return NULL;
1542 }
1543 EXPORT_SYMBOL_GPL(tracing_cond_snapshot_data);
tracing_snapshot_cond_enable(struct trace_array * tr,void * cond_data,cond_update_fn_t update)1544 int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data, cond_update_fn_t update)
1545 {
1546 return -ENODEV;
1547 }
1548 EXPORT_SYMBOL_GPL(tracing_snapshot_cond_enable);
tracing_snapshot_cond_disable(struct trace_array * tr)1549 int tracing_snapshot_cond_disable(struct trace_array *tr)
1550 {
1551 return false;
1552 }
1553 EXPORT_SYMBOL_GPL(tracing_snapshot_cond_disable);
1554 #define free_snapshot(tr) do { } while (0)
1555 #define tracing_arm_snapshot_locked(tr) ({ -EBUSY; })
1556 #endif /* CONFIG_TRACER_SNAPSHOT */
1557
tracer_tracing_off(struct trace_array * tr)1558 void tracer_tracing_off(struct trace_array *tr)
1559 {
1560 if (tr->array_buffer.buffer)
1561 ring_buffer_record_off(tr->array_buffer.buffer);
1562 /*
1563 * This flag is looked at when buffers haven't been allocated
1564 * yet, or by some tracers (like irqsoff), that just want to
1565 * know if the ring buffer has been disabled, but it can handle
1566 * races of where it gets disabled but we still do a record.
1567 * As the check is in the fast path of the tracers, it is more
1568 * important to be fast than accurate.
1569 */
1570 tr->buffer_disabled = 1;
1571 /* Make the flag seen by readers */
1572 smp_wmb();
1573 }
1574
1575 /**
1576 * tracing_off - turn off tracing buffers
1577 *
1578 * This function stops the tracing buffers from recording data.
1579 * It does not disable any overhead the tracers themselves may
1580 * be causing. This function simply causes all recording to
1581 * the ring buffers to fail.
1582 */
tracing_off(void)1583 void tracing_off(void)
1584 {
1585 tracer_tracing_off(&global_trace);
1586 }
1587 EXPORT_SYMBOL_GPL(tracing_off);
1588
disable_trace_on_warning(void)1589 void disable_trace_on_warning(void)
1590 {
1591 if (__disable_trace_on_warning) {
1592 trace_array_printk_buf(global_trace.array_buffer.buffer, _THIS_IP_,
1593 "Disabling tracing due to warning\n");
1594 tracing_off();
1595 }
1596 }
1597
1598 /**
1599 * tracer_tracing_is_on - show real state of ring buffer enabled
1600 * @tr : the trace array to know if ring buffer is enabled
1601 *
1602 * Shows real state of the ring buffer if it is enabled or not.
1603 */
tracer_tracing_is_on(struct trace_array * tr)1604 bool tracer_tracing_is_on(struct trace_array *tr)
1605 {
1606 if (tr->array_buffer.buffer)
1607 return ring_buffer_record_is_set_on(tr->array_buffer.buffer);
1608 return !tr->buffer_disabled;
1609 }
1610
1611 /**
1612 * tracing_is_on - show state of ring buffers enabled
1613 */
tracing_is_on(void)1614 int tracing_is_on(void)
1615 {
1616 return tracer_tracing_is_on(&global_trace);
1617 }
1618 EXPORT_SYMBOL_GPL(tracing_is_on);
1619
set_buf_size(char * str)1620 static int __init set_buf_size(char *str)
1621 {
1622 unsigned long buf_size;
1623
1624 if (!str)
1625 return 0;
1626 buf_size = memparse(str, &str);
1627 /*
1628 * nr_entries can not be zero and the startup
1629 * tests require some buffer space. Therefore
1630 * ensure we have at least 4096 bytes of buffer.
1631 */
1632 trace_buf_size = max(4096UL, buf_size);
1633 return 1;
1634 }
1635 __setup("trace_buf_size=", set_buf_size);
1636
set_tracing_thresh(char * str)1637 static int __init set_tracing_thresh(char *str)
1638 {
1639 unsigned long threshold;
1640 int ret;
1641
1642 if (!str)
1643 return 0;
1644 ret = kstrtoul(str, 0, &threshold);
1645 if (ret < 0)
1646 return 0;
1647 tracing_thresh = threshold * 1000;
1648 return 1;
1649 }
1650 __setup("tracing_thresh=", set_tracing_thresh);
1651
nsecs_to_usecs(unsigned long nsecs)1652 unsigned long nsecs_to_usecs(unsigned long nsecs)
1653 {
1654 return nsecs / 1000;
1655 }
1656
1657 /*
1658 * TRACE_FLAGS is defined as a tuple matching bit masks with strings.
1659 * It uses C(a, b) where 'a' is the eval (enum) name and 'b' is the string that
1660 * matches it. By defining "C(a, b) b", TRACE_FLAGS becomes a list
1661 * of strings in the order that the evals (enum) were defined.
1662 */
1663 #undef C
1664 #define C(a, b) b
1665
1666 /* These must match the bit positions in trace_iterator_flags */
1667 static const char *trace_options[] = {
1668 TRACE_FLAGS
1669 NULL
1670 };
1671
1672 static struct {
1673 u64 (*func)(void);
1674 const char *name;
1675 int in_ns; /* is this clock in nanoseconds? */
1676 } trace_clocks[] = {
1677 { trace_clock_local, "local", 1 },
1678 { trace_clock_global, "global", 1 },
1679 { trace_clock_counter, "counter", 0 },
1680 { trace_clock_jiffies, "uptime", 0 },
1681 { trace_clock, "perf", 1 },
1682 { ktime_get_mono_fast_ns, "mono", 1 },
1683 { ktime_get_raw_fast_ns, "mono_raw", 1 },
1684 { ktime_get_boot_fast_ns, "boot", 1 },
1685 { ktime_get_tai_fast_ns, "tai", 1 },
1686 ARCH_TRACE_CLOCKS
1687 };
1688
trace_clock_in_ns(struct trace_array * tr)1689 bool trace_clock_in_ns(struct trace_array *tr)
1690 {
1691 if (trace_clocks[tr->clock_id].in_ns)
1692 return true;
1693
1694 return false;
1695 }
1696
1697 /*
1698 * trace_parser_get_init - gets the buffer for trace parser
1699 */
trace_parser_get_init(struct trace_parser * parser,int size)1700 int trace_parser_get_init(struct trace_parser *parser, int size)
1701 {
1702 memset(parser, 0, sizeof(*parser));
1703
1704 parser->buffer = kmalloc(size, GFP_KERNEL);
1705 if (!parser->buffer)
1706 return 1;
1707
1708 parser->size = size;
1709 return 0;
1710 }
1711
1712 /*
1713 * trace_parser_put - frees the buffer for trace parser
1714 */
trace_parser_put(struct trace_parser * parser)1715 void trace_parser_put(struct trace_parser *parser)
1716 {
1717 kfree(parser->buffer);
1718 parser->buffer = NULL;
1719 }
1720
1721 /*
1722 * trace_get_user - reads the user input string separated by space
1723 * (matched by isspace(ch))
1724 *
1725 * For each string found the 'struct trace_parser' is updated,
1726 * and the function returns.
1727 *
1728 * Returns number of bytes read.
1729 *
1730 * See kernel/trace/trace.h for 'struct trace_parser' details.
1731 */
trace_get_user(struct trace_parser * parser,const char __user * ubuf,size_t cnt,loff_t * ppos)1732 int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
1733 size_t cnt, loff_t *ppos)
1734 {
1735 char ch;
1736 size_t read = 0;
1737 ssize_t ret;
1738
1739 if (!*ppos)
1740 trace_parser_clear(parser);
1741
1742 ret = get_user(ch, ubuf++);
1743 if (ret)
1744 goto out;
1745
1746 read++;
1747 cnt--;
1748
1749 /*
1750 * The parser is not finished with the last write,
1751 * continue reading the user input without skipping spaces.
1752 */
1753 if (!parser->cont) {
1754 /* skip white space */
1755 while (cnt && isspace(ch)) {
1756 ret = get_user(ch, ubuf++);
1757 if (ret)
1758 goto out;
1759 read++;
1760 cnt--;
1761 }
1762
1763 parser->idx = 0;
1764
1765 /* only spaces were written */
1766 if (isspace(ch) || !ch) {
1767 *ppos += read;
1768 ret = read;
1769 goto out;
1770 }
1771 }
1772
1773 /* read the non-space input */
1774 while (cnt && !isspace(ch) && ch) {
1775 if (parser->idx < parser->size - 1)
1776 parser->buffer[parser->idx++] = ch;
1777 else {
1778 ret = -EINVAL;
1779 goto out;
1780 }
1781 ret = get_user(ch, ubuf++);
1782 if (ret)
1783 goto out;
1784 read++;
1785 cnt--;
1786 }
1787
1788 /* We either got finished input or we have to wait for another call. */
1789 if (isspace(ch) || !ch) {
1790 parser->buffer[parser->idx] = 0;
1791 parser->cont = false;
1792 } else if (parser->idx < parser->size - 1) {
1793 parser->cont = true;
1794 parser->buffer[parser->idx++] = ch;
1795 /* Make sure the parsed string always terminates with '\0'. */
1796 parser->buffer[parser->idx] = 0;
1797 } else {
1798 ret = -EINVAL;
1799 goto out;
1800 }
1801
1802 *ppos += read;
1803 ret = read;
1804
1805 out:
1806 return ret;
1807 }
1808
1809 /* TODO add a seq_buf_to_buffer() */
trace_seq_to_buffer(struct trace_seq * s,void * buf,size_t cnt)1810 static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
1811 {
1812 int len;
1813
1814 if (trace_seq_used(s) <= s->readpos)
1815 return -EBUSY;
1816
1817 len = trace_seq_used(s) - s->readpos;
1818 if (cnt > len)
1819 cnt = len;
1820 memcpy(buf, s->buffer + s->readpos, cnt);
1821
1822 s->readpos += cnt;
1823 return cnt;
1824 }
1825
1826 unsigned long __read_mostly tracing_thresh;
1827
1828 #ifdef CONFIG_TRACER_MAX_TRACE
1829 static const struct file_operations tracing_max_lat_fops;
1830
1831 #ifdef LATENCY_FS_NOTIFY
1832
1833 static struct workqueue_struct *fsnotify_wq;
1834
latency_fsnotify_workfn(struct work_struct * work)1835 static void latency_fsnotify_workfn(struct work_struct *work)
1836 {
1837 struct trace_array *tr = container_of(work, struct trace_array,
1838 fsnotify_work);
1839 fsnotify_inode(tr->d_max_latency->d_inode, FS_MODIFY);
1840 }
1841
latency_fsnotify_workfn_irq(struct irq_work * iwork)1842 static void latency_fsnotify_workfn_irq(struct irq_work *iwork)
1843 {
1844 struct trace_array *tr = container_of(iwork, struct trace_array,
1845 fsnotify_irqwork);
1846 queue_work(fsnotify_wq, &tr->fsnotify_work);
1847 }
1848
trace_create_maxlat_file(struct trace_array * tr,struct dentry * d_tracer)1849 static void trace_create_maxlat_file(struct trace_array *tr,
1850 struct dentry *d_tracer)
1851 {
1852 INIT_WORK(&tr->fsnotify_work, latency_fsnotify_workfn);
1853 init_irq_work(&tr->fsnotify_irqwork, latency_fsnotify_workfn_irq);
1854 tr->d_max_latency = trace_create_file("tracing_max_latency",
1855 TRACE_MODE_WRITE,
1856 d_tracer, tr,
1857 &tracing_max_lat_fops);
1858 }
1859
latency_fsnotify_init(void)1860 __init static int latency_fsnotify_init(void)
1861 {
1862 fsnotify_wq = alloc_workqueue("tr_max_lat_wq",
1863 WQ_UNBOUND | WQ_HIGHPRI, 0);
1864 if (!fsnotify_wq) {
1865 pr_err("Unable to allocate tr_max_lat_wq\n");
1866 return -ENOMEM;
1867 }
1868 return 0;
1869 }
1870
1871 late_initcall_sync(latency_fsnotify_init);
1872
latency_fsnotify(struct trace_array * tr)1873 void latency_fsnotify(struct trace_array *tr)
1874 {
1875 if (!fsnotify_wq)
1876 return;
1877 /*
1878 * We cannot call queue_work(&tr->fsnotify_work) from here because it's
1879 * possible that we are called from __schedule() or do_idle(), which
1880 * could cause a deadlock.
1881 */
1882 irq_work_queue(&tr->fsnotify_irqwork);
1883 }
1884
1885 #else /* !LATENCY_FS_NOTIFY */
1886
1887 #define trace_create_maxlat_file(tr, d_tracer) \
1888 trace_create_file("tracing_max_latency", TRACE_MODE_WRITE, \
1889 d_tracer, tr, &tracing_max_lat_fops)
1890
1891 #endif
1892
1893 /*
1894 * Copy the new maximum trace into the separate maximum-trace
1895 * structure. (this way the maximum trace is permanently saved,
1896 * for later retrieval via /sys/kernel/tracing/tracing_max_latency)
1897 */
1898 static void
__update_max_tr(struct trace_array * tr,struct task_struct * tsk,int cpu)1899 __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
1900 {
1901 struct array_buffer *trace_buf = &tr->array_buffer;
1902 struct array_buffer *max_buf = &tr->max_buffer;
1903 struct trace_array_cpu *data = per_cpu_ptr(trace_buf->data, cpu);
1904 struct trace_array_cpu *max_data = per_cpu_ptr(max_buf->data, cpu);
1905
1906 max_buf->cpu = cpu;
1907 max_buf->time_start = data->preempt_timestamp;
1908
1909 max_data->saved_latency = tr->max_latency;
1910 max_data->critical_start = data->critical_start;
1911 max_data->critical_end = data->critical_end;
1912
1913 strscpy(max_data->comm, tsk->comm);
1914 max_data->pid = tsk->pid;
1915 /*
1916 * If tsk == current, then use current_uid(), as that does not use
1917 * RCU. The irq tracer can be called out of RCU scope.
1918 */
1919 if (tsk == current)
1920 max_data->uid = current_uid();
1921 else
1922 max_data->uid = task_uid(tsk);
1923
1924 max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
1925 max_data->policy = tsk->policy;
1926 max_data->rt_priority = tsk->rt_priority;
1927
1928 /* record this tasks comm */
1929 tracing_record_cmdline(tsk);
1930 latency_fsnotify(tr);
1931 }
1932
1933 /**
1934 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
1935 * @tr: tracer
1936 * @tsk: the task with the latency
1937 * @cpu: The cpu that initiated the trace.
1938 * @cond_data: User data associated with a conditional snapshot
1939 *
1940 * Flip the buffers between the @tr and the max_tr and record information
1941 * about which task was the cause of this latency.
1942 */
1943 void
update_max_tr(struct trace_array * tr,struct task_struct * tsk,int cpu,void * cond_data)1944 update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu,
1945 void *cond_data)
1946 {
1947 if (tr->stop_count)
1948 return;
1949
1950 WARN_ON_ONCE(!irqs_disabled());
1951
1952 if (!tr->allocated_snapshot) {
1953 /* Only the nop tracer should hit this when disabling */
1954 WARN_ON_ONCE(tr->current_trace != &nop_trace);
1955 return;
1956 }
1957
1958 arch_spin_lock(&tr->max_lock);
1959
1960 /* Inherit the recordable setting from array_buffer */
1961 if (ring_buffer_record_is_set_on(tr->array_buffer.buffer))
1962 ring_buffer_record_on(tr->max_buffer.buffer);
1963 else
1964 ring_buffer_record_off(tr->max_buffer.buffer);
1965
1966 #ifdef CONFIG_TRACER_SNAPSHOT
1967 if (tr->cond_snapshot && !tr->cond_snapshot->update(tr, cond_data)) {
1968 arch_spin_unlock(&tr->max_lock);
1969 return;
1970 }
1971 #endif
1972 swap(tr->array_buffer.buffer, tr->max_buffer.buffer);
1973
1974 __update_max_tr(tr, tsk, cpu);
1975
1976 arch_spin_unlock(&tr->max_lock);
1977
1978 /* Any waiters on the old snapshot buffer need to wake up */
1979 ring_buffer_wake_waiters(tr->array_buffer.buffer, RING_BUFFER_ALL_CPUS);
1980 }
1981
1982 /**
1983 * update_max_tr_single - only copy one trace over, and reset the rest
1984 * @tr: tracer
1985 * @tsk: task with the latency
1986 * @cpu: the cpu of the buffer to copy.
1987 *
1988 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
1989 */
1990 void
update_max_tr_single(struct trace_array * tr,struct task_struct * tsk,int cpu)1991 update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
1992 {
1993 int ret;
1994
1995 if (tr->stop_count)
1996 return;
1997
1998 WARN_ON_ONCE(!irqs_disabled());
1999 if (!tr->allocated_snapshot) {
2000 /* Only the nop tracer should hit this when disabling */
2001 WARN_ON_ONCE(tr->current_trace != &nop_trace);
2002 return;
2003 }
2004
2005 arch_spin_lock(&tr->max_lock);
2006
2007 ret = ring_buffer_swap_cpu(tr->max_buffer.buffer, tr->array_buffer.buffer, cpu);
2008
2009 if (ret == -EBUSY) {
2010 /*
2011 * We failed to swap the buffer due to a commit taking
2012 * place on this CPU. We fail to record, but we reset
2013 * the max trace buffer (no one writes directly to it)
2014 * and flag that it failed.
2015 * Another reason is resize is in progress.
2016 */
2017 trace_array_printk_buf(tr->max_buffer.buffer, _THIS_IP_,
2018 "Failed to swap buffers due to commit or resize in progress\n");
2019 }
2020
2021 WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);
2022
2023 __update_max_tr(tr, tsk, cpu);
2024 arch_spin_unlock(&tr->max_lock);
2025 }
2026
2027 #endif /* CONFIG_TRACER_MAX_TRACE */
2028
2029 struct pipe_wait {
2030 struct trace_iterator *iter;
2031 int wait_index;
2032 };
2033
wait_pipe_cond(void * data)2034 static bool wait_pipe_cond(void *data)
2035 {
2036 struct pipe_wait *pwait = data;
2037 struct trace_iterator *iter = pwait->iter;
2038
2039 if (atomic_read_acquire(&iter->wait_index) != pwait->wait_index)
2040 return true;
2041
2042 return iter->closed;
2043 }
2044
wait_on_pipe(struct trace_iterator * iter,int full)2045 static int wait_on_pipe(struct trace_iterator *iter, int full)
2046 {
2047 struct pipe_wait pwait;
2048 int ret;
2049
2050 /* Iterators are static, they should be filled or empty */
2051 if (trace_buffer_iter(iter, iter->cpu_file))
2052 return 0;
2053
2054 pwait.wait_index = atomic_read_acquire(&iter->wait_index);
2055 pwait.iter = iter;
2056
2057 ret = ring_buffer_wait(iter->array_buffer->buffer, iter->cpu_file, full,
2058 wait_pipe_cond, &pwait);
2059
2060 #ifdef CONFIG_TRACER_MAX_TRACE
2061 /*
2062 * Make sure this is still the snapshot buffer, as if a snapshot were
2063 * to happen, this would now be the main buffer.
2064 */
2065 if (iter->snapshot)
2066 iter->array_buffer = &iter->tr->max_buffer;
2067 #endif
2068 return ret;
2069 }
2070
2071 #ifdef CONFIG_FTRACE_STARTUP_TEST
2072 static bool selftests_can_run;
2073
2074 struct trace_selftests {
2075 struct list_head list;
2076 struct tracer *type;
2077 };
2078
2079 static LIST_HEAD(postponed_selftests);
2080
save_selftest(struct tracer * type)2081 static int save_selftest(struct tracer *type)
2082 {
2083 struct trace_selftests *selftest;
2084
2085 selftest = kmalloc(sizeof(*selftest), GFP_KERNEL);
2086 if (!selftest)
2087 return -ENOMEM;
2088
2089 selftest->type = type;
2090 list_add(&selftest->list, &postponed_selftests);
2091 return 0;
2092 }
2093
run_tracer_selftest(struct tracer * type)2094 static int run_tracer_selftest(struct tracer *type)
2095 {
2096 struct trace_array *tr = &global_trace;
2097 struct tracer *saved_tracer = tr->current_trace;
2098 int ret;
2099
2100 if (!type->selftest || tracing_selftest_disabled)
2101 return 0;
2102
2103 /*
2104 * If a tracer registers early in boot up (before scheduling is
2105 * initialized and such), then do not run its selftests yet.
2106 * Instead, run it a little later in the boot process.
2107 */
2108 if (!selftests_can_run)
2109 return save_selftest(type);
2110
2111 if (!tracing_is_on()) {
2112 pr_warn("Selftest for tracer %s skipped due to tracing disabled\n",
2113 type->name);
2114 return 0;
2115 }
2116
2117 /*
2118 * Run a selftest on this tracer.
2119 * Here we reset the trace buffer, and set the current
2120 * tracer to be this tracer. The tracer can then run some
2121 * internal tracing to verify that everything is in order.
2122 * If we fail, we do not register this tracer.
2123 */
2124 tracing_reset_online_cpus(&tr->array_buffer);
2125
2126 tr->current_trace = type;
2127
2128 #ifdef CONFIG_TRACER_MAX_TRACE
2129 if (type->use_max_tr) {
2130 /* If we expanded the buffers, make sure the max is expanded too */
2131 if (tr->ring_buffer_expanded)
2132 ring_buffer_resize(tr->max_buffer.buffer, trace_buf_size,
2133 RING_BUFFER_ALL_CPUS);
2134 tr->allocated_snapshot = true;
2135 }
2136 #endif
2137
2138 /* the test is responsible for initializing and enabling */
2139 pr_info("Testing tracer %s: ", type->name);
2140 ret = type->selftest(type, tr);
2141 /* the test is responsible for resetting too */
2142 tr->current_trace = saved_tracer;
2143 if (ret) {
2144 printk(KERN_CONT "FAILED!\n");
2145 /* Add the warning after printing 'FAILED' */
2146 WARN_ON(1);
2147 return -1;
2148 }
2149 /* Only reset on passing, to avoid touching corrupted buffers */
2150 tracing_reset_online_cpus(&tr->array_buffer);
2151
2152 #ifdef CONFIG_TRACER_MAX_TRACE
2153 if (type->use_max_tr) {
2154 tr->allocated_snapshot = false;
2155
2156 /* Shrink the max buffer again */
2157 if (tr->ring_buffer_expanded)
2158 ring_buffer_resize(tr->max_buffer.buffer, 1,
2159 RING_BUFFER_ALL_CPUS);
2160 }
2161 #endif
2162
2163 printk(KERN_CONT "PASSED\n");
2164 return 0;
2165 }
2166
do_run_tracer_selftest(struct tracer * type)2167 static int do_run_tracer_selftest(struct tracer *type)
2168 {
2169 int ret;
2170
2171 /*
2172 * Tests can take a long time, especially if they are run one after the
2173 * other, as does happen during bootup when all the tracers are
2174 * registered. This could cause the soft lockup watchdog to trigger.
2175 */
2176 cond_resched();
2177
2178 tracing_selftest_running = true;
2179 ret = run_tracer_selftest(type);
2180 tracing_selftest_running = false;
2181
2182 return ret;
2183 }
2184
init_trace_selftests(void)2185 static __init int init_trace_selftests(void)
2186 {
2187 struct trace_selftests *p, *n;
2188 struct tracer *t, **last;
2189 int ret;
2190
2191 selftests_can_run = true;
2192
2193 guard(mutex)(&trace_types_lock);
2194
2195 if (list_empty(&postponed_selftests))
2196 return 0;
2197
2198 pr_info("Running postponed tracer tests:\n");
2199
2200 tracing_selftest_running = true;
2201 list_for_each_entry_safe(p, n, &postponed_selftests, list) {
2202 /* This loop can take minutes when sanitizers are enabled, so
2203 * lets make sure we allow RCU processing.
2204 */
2205 cond_resched();
2206 ret = run_tracer_selftest(p->type);
2207 /* If the test fails, then warn and remove from available_tracers */
2208 if (ret < 0) {
2209 WARN(1, "tracer: %s failed selftest, disabling\n",
2210 p->type->name);
2211 last = &trace_types;
2212 for (t = trace_types; t; t = t->next) {
2213 if (t == p->type) {
2214 *last = t->next;
2215 break;
2216 }
2217 last = &t->next;
2218 }
2219 }
2220 list_del(&p->list);
2221 kfree(p);
2222 }
2223 tracing_selftest_running = false;
2224
2225 return 0;
2226 }
2227 core_initcall(init_trace_selftests);
2228 #else
do_run_tracer_selftest(struct tracer * type)2229 static inline int do_run_tracer_selftest(struct tracer *type)
2230 {
2231 return 0;
2232 }
2233 #endif /* CONFIG_FTRACE_STARTUP_TEST */
2234
2235 static void add_tracer_options(struct trace_array *tr, struct tracer *t);
2236
2237 static void __init apply_trace_boot_options(void);
2238
2239 /**
2240 * register_tracer - register a tracer with the ftrace system.
2241 * @type: the plugin for the tracer
2242 *
2243 * Register a new plugin tracer.
2244 */
register_tracer(struct tracer * type)2245 int __init register_tracer(struct tracer *type)
2246 {
2247 struct tracer *t;
2248 int ret = 0;
2249
2250 if (!type->name) {
2251 pr_info("Tracer must have a name\n");
2252 return -1;
2253 }
2254
2255 if (strlen(type->name) >= MAX_TRACER_SIZE) {
2256 pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE);
2257 return -1;
2258 }
2259
2260 if (security_locked_down(LOCKDOWN_TRACEFS)) {
2261 pr_warn("Can not register tracer %s due to lockdown\n",
2262 type->name);
2263 return -EPERM;
2264 }
2265
2266 mutex_lock(&trace_types_lock);
2267
2268 for (t = trace_types; t; t = t->next) {
2269 if (strcmp(type->name, t->name) == 0) {
2270 /* already found */
2271 pr_info("Tracer %s already registered\n",
2272 type->name);
2273 ret = -1;
2274 goto out;
2275 }
2276 }
2277
2278 if (!type->set_flag)
2279 type->set_flag = &dummy_set_flag;
2280 if (!type->flags) {
2281 /*allocate a dummy tracer_flags*/
2282 type->flags = kmalloc(sizeof(*type->flags), GFP_KERNEL);
2283 if (!type->flags) {
2284 ret = -ENOMEM;
2285 goto out;
2286 }
2287 type->flags->val = 0;
2288 type->flags->opts = dummy_tracer_opt;
2289 } else
2290 if (!type->flags->opts)
2291 type->flags->opts = dummy_tracer_opt;
2292
2293 /* store the tracer for __set_tracer_option */
2294 type->flags->trace = type;
2295
2296 ret = do_run_tracer_selftest(type);
2297 if (ret < 0)
2298 goto out;
2299
2300 type->next = trace_types;
2301 trace_types = type;
2302 add_tracer_options(&global_trace, type);
2303
2304 out:
2305 mutex_unlock(&trace_types_lock);
2306
2307 if (ret || !default_bootup_tracer)
2308 goto out_unlock;
2309
2310 if (strncmp(default_bootup_tracer, type->name, MAX_TRACER_SIZE))
2311 goto out_unlock;
2312
2313 printk(KERN_INFO "Starting tracer '%s'\n", type->name);
2314 /* Do we want this tracer to start on bootup? */
2315 tracing_set_tracer(&global_trace, type->name);
2316 default_bootup_tracer = NULL;
2317
2318 apply_trace_boot_options();
2319
2320 /* disable other selftests, since this will break it. */
2321 disable_tracing_selftest("running a tracer");
2322
2323 out_unlock:
2324 return ret;
2325 }
2326
tracing_reset_cpu(struct array_buffer * buf,int cpu)2327 static void tracing_reset_cpu(struct array_buffer *buf, int cpu)
2328 {
2329 struct trace_buffer *buffer = buf->buffer;
2330
2331 if (!buffer)
2332 return;
2333
2334 ring_buffer_record_disable(buffer);
2335
2336 /* Make sure all commits have finished */
2337 synchronize_rcu();
2338 ring_buffer_reset_cpu(buffer, cpu);
2339
2340 ring_buffer_record_enable(buffer);
2341 }
2342
tracing_reset_online_cpus(struct array_buffer * buf)2343 void tracing_reset_online_cpus(struct array_buffer *buf)
2344 {
2345 struct trace_buffer *buffer = buf->buffer;
2346
2347 if (!buffer)
2348 return;
2349
2350 ring_buffer_record_disable(buffer);
2351
2352 /* Make sure all commits have finished */
2353 synchronize_rcu();
2354
2355 buf->time_start = buffer_ftrace_now(buf, buf->cpu);
2356
2357 ring_buffer_reset_online_cpus(buffer);
2358
2359 ring_buffer_record_enable(buffer);
2360 }
2361
tracing_reset_all_cpus(struct array_buffer * buf)2362 static void tracing_reset_all_cpus(struct array_buffer *buf)
2363 {
2364 struct trace_buffer *buffer = buf->buffer;
2365
2366 if (!buffer)
2367 return;
2368
2369 ring_buffer_record_disable(buffer);
2370
2371 /* Make sure all commits have finished */
2372 synchronize_rcu();
2373
2374 buf->time_start = buffer_ftrace_now(buf, buf->cpu);
2375
2376 ring_buffer_reset(buffer);
2377
2378 ring_buffer_record_enable(buffer);
2379 }
2380
2381 /* Must have trace_types_lock held */
tracing_reset_all_online_cpus_unlocked(void)2382 void tracing_reset_all_online_cpus_unlocked(void)
2383 {
2384 struct trace_array *tr;
2385
2386 lockdep_assert_held(&trace_types_lock);
2387
2388 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
2389 if (!tr->clear_trace)
2390 continue;
2391 tr->clear_trace = false;
2392 tracing_reset_online_cpus(&tr->array_buffer);
2393 #ifdef CONFIG_TRACER_MAX_TRACE
2394 tracing_reset_online_cpus(&tr->max_buffer);
2395 #endif
2396 }
2397 }
2398
tracing_reset_all_online_cpus(void)2399 void tracing_reset_all_online_cpus(void)
2400 {
2401 mutex_lock(&trace_types_lock);
2402 tracing_reset_all_online_cpus_unlocked();
2403 mutex_unlock(&trace_types_lock);
2404 }
2405
is_tracing_stopped(void)2406 int is_tracing_stopped(void)
2407 {
2408 return global_trace.stop_count;
2409 }
2410
tracing_start_tr(struct trace_array * tr)2411 static void tracing_start_tr(struct trace_array *tr)
2412 {
2413 struct trace_buffer *buffer;
2414 unsigned long flags;
2415
2416 if (tracing_disabled)
2417 return;
2418
2419 raw_spin_lock_irqsave(&tr->start_lock, flags);
2420 if (--tr->stop_count) {
2421 if (WARN_ON_ONCE(tr->stop_count < 0)) {
2422 /* Someone screwed up their debugging */
2423 tr->stop_count = 0;
2424 }
2425 goto out;
2426 }
2427
2428 /* Prevent the buffers from switching */
2429 arch_spin_lock(&tr->max_lock);
2430
2431 buffer = tr->array_buffer.buffer;
2432 if (buffer)
2433 ring_buffer_record_enable(buffer);
2434
2435 #ifdef CONFIG_TRACER_MAX_TRACE
2436 buffer = tr->max_buffer.buffer;
2437 if (buffer)
2438 ring_buffer_record_enable(buffer);
2439 #endif
2440
2441 arch_spin_unlock(&tr->max_lock);
2442
2443 out:
2444 raw_spin_unlock_irqrestore(&tr->start_lock, flags);
2445 }
2446
2447 /**
2448 * tracing_start - quick start of the tracer
2449 *
2450 * If tracing is enabled but was stopped by tracing_stop,
2451 * this will start the tracer back up.
2452 */
tracing_start(void)2453 void tracing_start(void)
2454
2455 {
2456 return tracing_start_tr(&global_trace);
2457 }
2458
tracing_stop_tr(struct trace_array * tr)2459 static void tracing_stop_tr(struct trace_array *tr)
2460 {
2461 struct trace_buffer *buffer;
2462 unsigned long flags;
2463
2464 raw_spin_lock_irqsave(&tr->start_lock, flags);
2465 if (tr->stop_count++)
2466 goto out;
2467
2468 /* Prevent the buffers from switching */
2469 arch_spin_lock(&tr->max_lock);
2470
2471 buffer = tr->array_buffer.buffer;
2472 if (buffer)
2473 ring_buffer_record_disable(buffer);
2474
2475 #ifdef CONFIG_TRACER_MAX_TRACE
2476 buffer = tr->max_buffer.buffer;
2477 if (buffer)
2478 ring_buffer_record_disable(buffer);
2479 #endif
2480
2481 arch_spin_unlock(&tr->max_lock);
2482
2483 out:
2484 raw_spin_unlock_irqrestore(&tr->start_lock, flags);
2485 }
2486
2487 /**
2488 * tracing_stop - quick stop of the tracer
2489 *
2490 * Light weight way to stop tracing. Use in conjunction with
2491 * tracing_start.
2492 */
tracing_stop(void)2493 void tracing_stop(void)
2494 {
2495 return tracing_stop_tr(&global_trace);
2496 }
2497
2498 /*
2499 * Several functions return TRACE_TYPE_PARTIAL_LINE if the trace_seq
2500 * overflowed, and TRACE_TYPE_HANDLED otherwise. This helper function
2501 * simplifies those functions and keeps them in sync.
2502 */
trace_handle_return(struct trace_seq * s)2503 enum print_line_t trace_handle_return(struct trace_seq *s)
2504 {
2505 return trace_seq_has_overflowed(s) ?
2506 TRACE_TYPE_PARTIAL_LINE : TRACE_TYPE_HANDLED;
2507 }
2508 EXPORT_SYMBOL_GPL(trace_handle_return);
2509
migration_disable_value(void)2510 static unsigned short migration_disable_value(void)
2511 {
2512 #if defined(CONFIG_SMP)
2513 return current->migration_disabled;
2514 #else
2515 return 0;
2516 #endif
2517 }
2518
tracing_gen_ctx_irq_test(unsigned int irqs_status)2519 unsigned int tracing_gen_ctx_irq_test(unsigned int irqs_status)
2520 {
2521 unsigned int trace_flags = irqs_status;
2522 unsigned int pc;
2523
2524 pc = preempt_count();
2525
2526 if (pc & NMI_MASK)
2527 trace_flags |= TRACE_FLAG_NMI;
2528 if (pc & HARDIRQ_MASK)
2529 trace_flags |= TRACE_FLAG_HARDIRQ;
2530 if (in_serving_softirq())
2531 trace_flags |= TRACE_FLAG_SOFTIRQ;
2532 if (softirq_count() >> (SOFTIRQ_SHIFT + 1))
2533 trace_flags |= TRACE_FLAG_BH_OFF;
2534
2535 if (tif_need_resched())
2536 trace_flags |= TRACE_FLAG_NEED_RESCHED;
2537 if (test_preempt_need_resched())
2538 trace_flags |= TRACE_FLAG_PREEMPT_RESCHED;
2539 if (IS_ENABLED(CONFIG_ARCH_HAS_PREEMPT_LAZY) && tif_test_bit(TIF_NEED_RESCHED_LAZY))
2540 trace_flags |= TRACE_FLAG_NEED_RESCHED_LAZY;
2541 return (trace_flags << 16) | (min_t(unsigned int, pc & 0xff, 0xf)) |
2542 (min_t(unsigned int, migration_disable_value(), 0xf)) << 4;
2543 }
2544
2545 struct ring_buffer_event *
trace_buffer_lock_reserve(struct trace_buffer * buffer,int type,unsigned long len,unsigned int trace_ctx)2546 trace_buffer_lock_reserve(struct trace_buffer *buffer,
2547 int type,
2548 unsigned long len,
2549 unsigned int trace_ctx)
2550 {
2551 return __trace_buffer_lock_reserve(buffer, type, len, trace_ctx);
2552 }
2553
2554 DEFINE_PER_CPU(struct ring_buffer_event *, trace_buffered_event);
2555 DEFINE_PER_CPU(int, trace_buffered_event_cnt);
2556 static int trace_buffered_event_ref;
2557
2558 /**
2559 * trace_buffered_event_enable - enable buffering events
2560 *
2561 * When events are being filtered, it is quicker to use a temporary
2562 * buffer to write the event data into if there's a likely chance
2563 * that it will not be committed. The discard of the ring buffer
2564 * is not as fast as committing, and is much slower than copying
2565 * a commit.
2566 *
2567 * When an event is to be filtered, allocate per cpu buffers to
2568 * write the event data into, and if the event is filtered and discarded
2569 * it is simply dropped, otherwise, the entire data is to be committed
2570 * in one shot.
2571 */
trace_buffered_event_enable(void)2572 void trace_buffered_event_enable(void)
2573 {
2574 struct ring_buffer_event *event;
2575 struct page *page;
2576 int cpu;
2577
2578 WARN_ON_ONCE(!mutex_is_locked(&event_mutex));
2579
2580 if (trace_buffered_event_ref++)
2581 return;
2582
2583 for_each_tracing_cpu(cpu) {
2584 page = alloc_pages_node(cpu_to_node(cpu),
2585 GFP_KERNEL | __GFP_NORETRY, 0);
2586 /* This is just an optimization and can handle failures */
2587 if (!page) {
2588 pr_err("Failed to allocate event buffer\n");
2589 break;
2590 }
2591
2592 event = page_address(page);
2593 memset(event, 0, sizeof(*event));
2594
2595 per_cpu(trace_buffered_event, cpu) = event;
2596
2597 preempt_disable();
2598 if (cpu == smp_processor_id() &&
2599 __this_cpu_read(trace_buffered_event) !=
2600 per_cpu(trace_buffered_event, cpu))
2601 WARN_ON_ONCE(1);
2602 preempt_enable();
2603 }
2604 }
2605
enable_trace_buffered_event(void * data)2606 static void enable_trace_buffered_event(void *data)
2607 {
2608 /* Probably not needed, but do it anyway */
2609 smp_rmb();
2610 this_cpu_dec(trace_buffered_event_cnt);
2611 }
2612
disable_trace_buffered_event(void * data)2613 static void disable_trace_buffered_event(void *data)
2614 {
2615 this_cpu_inc(trace_buffered_event_cnt);
2616 }
2617
2618 /**
2619 * trace_buffered_event_disable - disable buffering events
2620 *
2621 * When a filter is removed, it is faster to not use the buffered
2622 * events, and to commit directly into the ring buffer. Free up
2623 * the temp buffers when there are no more users. This requires
2624 * special synchronization with current events.
2625 */
trace_buffered_event_disable(void)2626 void trace_buffered_event_disable(void)
2627 {
2628 int cpu;
2629
2630 WARN_ON_ONCE(!mutex_is_locked(&event_mutex));
2631
2632 if (WARN_ON_ONCE(!trace_buffered_event_ref))
2633 return;
2634
2635 if (--trace_buffered_event_ref)
2636 return;
2637
2638 /* For each CPU, set the buffer as used. */
2639 on_each_cpu_mask(tracing_buffer_mask, disable_trace_buffered_event,
2640 NULL, true);
2641
2642 /* Wait for all current users to finish */
2643 synchronize_rcu();
2644
2645 for_each_tracing_cpu(cpu) {
2646 free_page((unsigned long)per_cpu(trace_buffered_event, cpu));
2647 per_cpu(trace_buffered_event, cpu) = NULL;
2648 }
2649
2650 /*
2651 * Wait for all CPUs that potentially started checking if they can use
2652 * their event buffer only after the previous synchronize_rcu() call and
2653 * they still read a valid pointer from trace_buffered_event. It must be
2654 * ensured they don't see cleared trace_buffered_event_cnt else they
2655 * could wrongly decide to use the pointed-to buffer which is now freed.
2656 */
2657 synchronize_rcu();
2658
2659 /* For each CPU, relinquish the buffer */
2660 on_each_cpu_mask(tracing_buffer_mask, enable_trace_buffered_event, NULL,
2661 true);
2662 }
2663
2664 static struct trace_buffer *temp_buffer;
2665
2666 struct ring_buffer_event *
trace_event_buffer_lock_reserve(struct trace_buffer ** current_rb,struct trace_event_file * trace_file,int type,unsigned long len,unsigned int trace_ctx)2667 trace_event_buffer_lock_reserve(struct trace_buffer **current_rb,
2668 struct trace_event_file *trace_file,
2669 int type, unsigned long len,
2670 unsigned int trace_ctx)
2671 {
2672 struct ring_buffer_event *entry;
2673 struct trace_array *tr = trace_file->tr;
2674 int val;
2675
2676 *current_rb = tr->array_buffer.buffer;
2677
2678 if (!tr->no_filter_buffering_ref &&
2679 (trace_file->flags & (EVENT_FILE_FL_SOFT_DISABLED | EVENT_FILE_FL_FILTERED))) {
2680 preempt_disable_notrace();
2681 /*
2682 * Filtering is on, so try to use the per cpu buffer first.
2683 * This buffer will simulate a ring_buffer_event,
2684 * where the type_len is zero and the array[0] will
2685 * hold the full length.
2686 * (see include/linux/ring-buffer.h for details on
2687 * how the ring_buffer_event is structured).
2688 *
2689 * Using a temp buffer during filtering and copying it
2690 * on a matched filter is quicker than writing directly
2691 * into the ring buffer and then discarding it when
2692 * it doesn't match. That is because the discard
2693 * requires several atomic operations to get right.
2694 * Copying on match and doing nothing on a failed match
2695 * is still quicker than no copy on match, but having
2696 * to discard out of the ring buffer on a failed match.
2697 */
2698 if ((entry = __this_cpu_read(trace_buffered_event))) {
2699 int max_len = PAGE_SIZE - struct_size(entry, array, 1);
2700
2701 val = this_cpu_inc_return(trace_buffered_event_cnt);
2702
2703 /*
2704 * Preemption is disabled, but interrupts and NMIs
2705 * can still come in now. If that happens after
2706 * the above increment, then it will have to go
2707 * back to the old method of allocating the event
2708 * on the ring buffer, and if the filter fails, it
2709 * will have to call ring_buffer_discard_commit()
2710 * to remove it.
2711 *
2712 * Need to also check the unlikely case that the
2713 * length is bigger than the temp buffer size.
2714 * If that happens, then the reserve is pretty much
2715 * guaranteed to fail, as the ring buffer currently
2716 * only allows events less than a page. But that may
2717 * change in the future, so let the ring buffer reserve
2718 * handle the failure in that case.
2719 */
2720 if (val == 1 && likely(len <= max_len)) {
2721 trace_event_setup(entry, type, trace_ctx);
2722 entry->array[0] = len;
2723 /* Return with preemption disabled */
2724 return entry;
2725 }
2726 this_cpu_dec(trace_buffered_event_cnt);
2727 }
2728 /* __trace_buffer_lock_reserve() disables preemption */
2729 preempt_enable_notrace();
2730 }
2731
2732 entry = __trace_buffer_lock_reserve(*current_rb, type, len,
2733 trace_ctx);
2734 /*
2735 * If tracing is off, but we have triggers enabled
2736 * we still need to look at the event data. Use the temp_buffer
2737 * to store the trace event for the trigger to use. It's recursive
2738 * safe and will not be recorded anywhere.
2739 */
2740 if (!entry && trace_file->flags & EVENT_FILE_FL_TRIGGER_COND) {
2741 *current_rb = temp_buffer;
2742 entry = __trace_buffer_lock_reserve(*current_rb, type, len,
2743 trace_ctx);
2744 }
2745 return entry;
2746 }
2747 EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve);
2748
2749 static DEFINE_RAW_SPINLOCK(tracepoint_iter_lock);
2750 static DEFINE_MUTEX(tracepoint_printk_mutex);
2751
output_printk(struct trace_event_buffer * fbuffer)2752 static void output_printk(struct trace_event_buffer *fbuffer)
2753 {
2754 struct trace_event_call *event_call;
2755 struct trace_event_file *file;
2756 struct trace_event *event;
2757 unsigned long flags;
2758 struct trace_iterator *iter = tracepoint_print_iter;
2759
2760 /* We should never get here if iter is NULL */
2761 if (WARN_ON_ONCE(!iter))
2762 return;
2763
2764 event_call = fbuffer->trace_file->event_call;
2765 if (!event_call || !event_call->event.funcs ||
2766 !event_call->event.funcs->trace)
2767 return;
2768
2769 file = fbuffer->trace_file;
2770 if (test_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags) ||
2771 (unlikely(file->flags & EVENT_FILE_FL_FILTERED) &&
2772 !filter_match_preds(file->filter, fbuffer->entry)))
2773 return;
2774
2775 event = &fbuffer->trace_file->event_call->event;
2776
2777 raw_spin_lock_irqsave(&tracepoint_iter_lock, flags);
2778 trace_seq_init(&iter->seq);
2779 iter->ent = fbuffer->entry;
2780 event_call->event.funcs->trace(iter, 0, event);
2781 trace_seq_putc(&iter->seq, 0);
2782 printk("%s", iter->seq.buffer);
2783
2784 raw_spin_unlock_irqrestore(&tracepoint_iter_lock, flags);
2785 }
2786
tracepoint_printk_sysctl(const struct ctl_table * table,int write,void * buffer,size_t * lenp,loff_t * ppos)2787 int tracepoint_printk_sysctl(const struct ctl_table *table, int write,
2788 void *buffer, size_t *lenp,
2789 loff_t *ppos)
2790 {
2791 int save_tracepoint_printk;
2792 int ret;
2793
2794 guard(mutex)(&tracepoint_printk_mutex);
2795 save_tracepoint_printk = tracepoint_printk;
2796
2797 ret = proc_dointvec(table, write, buffer, lenp, ppos);
2798
2799 /*
2800 * This will force exiting early, as tracepoint_printk
2801 * is always zero when tracepoint_printk_iter is not allocated
2802 */
2803 if (!tracepoint_print_iter)
2804 tracepoint_printk = 0;
2805
2806 if (save_tracepoint_printk == tracepoint_printk)
2807 return ret;
2808
2809 if (tracepoint_printk)
2810 static_key_enable(&tracepoint_printk_key.key);
2811 else
2812 static_key_disable(&tracepoint_printk_key.key);
2813
2814 return ret;
2815 }
2816
trace_event_buffer_commit(struct trace_event_buffer * fbuffer)2817 void trace_event_buffer_commit(struct trace_event_buffer *fbuffer)
2818 {
2819 enum event_trigger_type tt = ETT_NONE;
2820 struct trace_event_file *file = fbuffer->trace_file;
2821
2822 if (__event_trigger_test_discard(file, fbuffer->buffer, fbuffer->event,
2823 fbuffer->entry, &tt))
2824 goto discard;
2825
2826 if (static_key_false(&tracepoint_printk_key.key))
2827 output_printk(fbuffer);
2828
2829 if (static_branch_unlikely(&trace_event_exports_enabled))
2830 ftrace_exports(fbuffer->event, TRACE_EXPORT_EVENT);
2831
2832 trace_buffer_unlock_commit_regs(file->tr, fbuffer->buffer,
2833 fbuffer->event, fbuffer->trace_ctx, fbuffer->regs);
2834
2835 discard:
2836 if (tt)
2837 event_triggers_post_call(file, tt);
2838
2839 }
2840 EXPORT_SYMBOL_GPL(trace_event_buffer_commit);
2841
2842 /*
2843 * Skip 3:
2844 *
2845 * trace_buffer_unlock_commit_regs()
2846 * trace_event_buffer_commit()
2847 * trace_event_raw_event_xxx()
2848 */
2849 # define STACK_SKIP 3
2850
trace_buffer_unlock_commit_regs(struct trace_array * tr,struct trace_buffer * buffer,struct ring_buffer_event * event,unsigned int trace_ctx,struct pt_regs * regs)2851 void trace_buffer_unlock_commit_regs(struct trace_array *tr,
2852 struct trace_buffer *buffer,
2853 struct ring_buffer_event *event,
2854 unsigned int trace_ctx,
2855 struct pt_regs *regs)
2856 {
2857 __buffer_unlock_commit(buffer, event);
2858
2859 /*
2860 * If regs is not set, then skip the necessary functions.
2861 * Note, we can still get here via blktrace, wakeup tracer
2862 * and mmiotrace, but that's ok if they lose a function or
2863 * two. They are not that meaningful.
2864 */
2865 ftrace_trace_stack(tr, buffer, trace_ctx, regs ? 0 : STACK_SKIP, regs);
2866 ftrace_trace_userstack(tr, buffer, trace_ctx);
2867 }
2868
2869 /*
2870 * Similar to trace_buffer_unlock_commit_regs() but do not dump stack.
2871 */
2872 void
trace_buffer_unlock_commit_nostack(struct trace_buffer * buffer,struct ring_buffer_event * event)2873 trace_buffer_unlock_commit_nostack(struct trace_buffer *buffer,
2874 struct ring_buffer_event *event)
2875 {
2876 __buffer_unlock_commit(buffer, event);
2877 }
2878
2879 void
trace_function(struct trace_array * tr,unsigned long ip,unsigned long parent_ip,unsigned int trace_ctx)2880 trace_function(struct trace_array *tr, unsigned long ip, unsigned long
2881 parent_ip, unsigned int trace_ctx)
2882 {
2883 struct trace_buffer *buffer = tr->array_buffer.buffer;
2884 struct ring_buffer_event *event;
2885 struct ftrace_entry *entry;
2886
2887 event = __trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
2888 trace_ctx);
2889 if (!event)
2890 return;
2891 entry = ring_buffer_event_data(event);
2892 entry->ip = ip;
2893 entry->parent_ip = parent_ip;
2894
2895 if (static_branch_unlikely(&trace_function_exports_enabled))
2896 ftrace_exports(event, TRACE_EXPORT_FUNCTION);
2897 __buffer_unlock_commit(buffer, event);
2898 }
2899
2900 #ifdef CONFIG_STACKTRACE
2901
2902 /* Allow 4 levels of nesting: normal, softirq, irq, NMI */
2903 #define FTRACE_KSTACK_NESTING 4
2904
2905 #define FTRACE_KSTACK_ENTRIES (SZ_4K / FTRACE_KSTACK_NESTING)
2906
2907 struct ftrace_stack {
2908 unsigned long calls[FTRACE_KSTACK_ENTRIES];
2909 };
2910
2911
2912 struct ftrace_stacks {
2913 struct ftrace_stack stacks[FTRACE_KSTACK_NESTING];
2914 };
2915
2916 static DEFINE_PER_CPU(struct ftrace_stacks, ftrace_stacks);
2917 static DEFINE_PER_CPU(int, ftrace_stack_reserve);
2918
__ftrace_trace_stack(struct trace_array * tr,struct trace_buffer * buffer,unsigned int trace_ctx,int skip,struct pt_regs * regs)2919 static void __ftrace_trace_stack(struct trace_array *tr,
2920 struct trace_buffer *buffer,
2921 unsigned int trace_ctx,
2922 int skip, struct pt_regs *regs)
2923 {
2924 struct ring_buffer_event *event;
2925 unsigned int size, nr_entries;
2926 struct ftrace_stack *fstack;
2927 struct stack_entry *entry;
2928 int stackidx;
2929
2930 /*
2931 * Add one, for this function and the call to save_stack_trace()
2932 * If regs is set, then these functions will not be in the way.
2933 */
2934 #ifndef CONFIG_UNWINDER_ORC
2935 if (!regs)
2936 skip++;
2937 #endif
2938
2939 preempt_disable_notrace();
2940
2941 stackidx = __this_cpu_inc_return(ftrace_stack_reserve) - 1;
2942
2943 /* This should never happen. If it does, yell once and skip */
2944 if (WARN_ON_ONCE(stackidx >= FTRACE_KSTACK_NESTING))
2945 goto out;
2946
2947 /*
2948 * The above __this_cpu_inc_return() is 'atomic' cpu local. An
2949 * interrupt will either see the value pre increment or post
2950 * increment. If the interrupt happens pre increment it will have
2951 * restored the counter when it returns. We just need a barrier to
2952 * keep gcc from moving things around.
2953 */
2954 barrier();
2955
2956 fstack = this_cpu_ptr(ftrace_stacks.stacks) + stackidx;
2957 size = ARRAY_SIZE(fstack->calls);
2958
2959 if (regs) {
2960 nr_entries = stack_trace_save_regs(regs, fstack->calls,
2961 size, skip);
2962 } else {
2963 nr_entries = stack_trace_save(fstack->calls, size, skip);
2964 }
2965
2966 #ifdef CONFIG_DYNAMIC_FTRACE
2967 /* Mark entry of stack trace as trampoline code */
2968 if (tr->ops && tr->ops->trampoline) {
2969 unsigned long tramp_start = tr->ops->trampoline;
2970 unsigned long tramp_end = tramp_start + tr->ops->trampoline_size;
2971 unsigned long *calls = fstack->calls;
2972
2973 for (int i = 0; i < nr_entries; i++) {
2974 if (calls[i] >= tramp_start && calls[i] < tramp_end)
2975 calls[i] = FTRACE_TRAMPOLINE_MARKER;
2976 }
2977 }
2978 #endif
2979
2980 event = __trace_buffer_lock_reserve(buffer, TRACE_STACK,
2981 struct_size(entry, caller, nr_entries),
2982 trace_ctx);
2983 if (!event)
2984 goto out;
2985 entry = ring_buffer_event_data(event);
2986
2987 entry->size = nr_entries;
2988 memcpy(&entry->caller, fstack->calls,
2989 flex_array_size(entry, caller, nr_entries));
2990
2991 __buffer_unlock_commit(buffer, event);
2992
2993 out:
2994 /* Again, don't let gcc optimize things here */
2995 barrier();
2996 __this_cpu_dec(ftrace_stack_reserve);
2997 preempt_enable_notrace();
2998
2999 }
3000
ftrace_trace_stack(struct trace_array * tr,struct trace_buffer * buffer,unsigned int trace_ctx,int skip,struct pt_regs * regs)3001 static inline void ftrace_trace_stack(struct trace_array *tr,
3002 struct trace_buffer *buffer,
3003 unsigned int trace_ctx,
3004 int skip, struct pt_regs *regs)
3005 {
3006 if (!(tr->trace_flags & TRACE_ITER_STACKTRACE))
3007 return;
3008
3009 __ftrace_trace_stack(tr, buffer, trace_ctx, skip, regs);
3010 }
3011
__trace_stack(struct trace_array * tr,unsigned int trace_ctx,int skip)3012 void __trace_stack(struct trace_array *tr, unsigned int trace_ctx,
3013 int skip)
3014 {
3015 struct trace_buffer *buffer = tr->array_buffer.buffer;
3016
3017 if (rcu_is_watching()) {
3018 __ftrace_trace_stack(tr, buffer, trace_ctx, skip, NULL);
3019 return;
3020 }
3021
3022 if (WARN_ON_ONCE(IS_ENABLED(CONFIG_GENERIC_ENTRY)))
3023 return;
3024
3025 /*
3026 * When an NMI triggers, RCU is enabled via ct_nmi_enter(),
3027 * but if the above rcu_is_watching() failed, then the NMI
3028 * triggered someplace critical, and ct_irq_enter() should
3029 * not be called from NMI.
3030 */
3031 if (unlikely(in_nmi()))
3032 return;
3033
3034 ct_irq_enter_irqson();
3035 __ftrace_trace_stack(tr, buffer, trace_ctx, skip, NULL);
3036 ct_irq_exit_irqson();
3037 }
3038
3039 /**
3040 * trace_dump_stack - record a stack back trace in the trace buffer
3041 * @skip: Number of functions to skip (helper handlers)
3042 */
trace_dump_stack(int skip)3043 void trace_dump_stack(int skip)
3044 {
3045 if (tracing_disabled || tracing_selftest_running)
3046 return;
3047
3048 #ifndef CONFIG_UNWINDER_ORC
3049 /* Skip 1 to skip this function. */
3050 skip++;
3051 #endif
3052 __ftrace_trace_stack(printk_trace, printk_trace->array_buffer.buffer,
3053 tracing_gen_ctx(), skip, NULL);
3054 }
3055 EXPORT_SYMBOL_GPL(trace_dump_stack);
3056
3057 #ifdef CONFIG_USER_STACKTRACE_SUPPORT
3058 static DEFINE_PER_CPU(int, user_stack_count);
3059
3060 static void
ftrace_trace_userstack(struct trace_array * tr,struct trace_buffer * buffer,unsigned int trace_ctx)3061 ftrace_trace_userstack(struct trace_array *tr,
3062 struct trace_buffer *buffer, unsigned int trace_ctx)
3063 {
3064 struct ring_buffer_event *event;
3065 struct userstack_entry *entry;
3066
3067 if (!(tr->trace_flags & TRACE_ITER_USERSTACKTRACE))
3068 return;
3069
3070 /*
3071 * NMIs can not handle page faults, even with fix ups.
3072 * The save user stack can (and often does) fault.
3073 */
3074 if (unlikely(in_nmi()))
3075 return;
3076
3077 /*
3078 * prevent recursion, since the user stack tracing may
3079 * trigger other kernel events.
3080 */
3081 preempt_disable();
3082 if (__this_cpu_read(user_stack_count))
3083 goto out;
3084
3085 __this_cpu_inc(user_stack_count);
3086
3087 event = __trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
3088 sizeof(*entry), trace_ctx);
3089 if (!event)
3090 goto out_drop_count;
3091 entry = ring_buffer_event_data(event);
3092
3093 entry->tgid = current->tgid;
3094 memset(&entry->caller, 0, sizeof(entry->caller));
3095
3096 stack_trace_save_user(entry->caller, FTRACE_STACK_ENTRIES);
3097 __buffer_unlock_commit(buffer, event);
3098
3099 out_drop_count:
3100 __this_cpu_dec(user_stack_count);
3101 out:
3102 preempt_enable();
3103 }
3104 #else /* CONFIG_USER_STACKTRACE_SUPPORT */
ftrace_trace_userstack(struct trace_array * tr,struct trace_buffer * buffer,unsigned int trace_ctx)3105 static void ftrace_trace_userstack(struct trace_array *tr,
3106 struct trace_buffer *buffer,
3107 unsigned int trace_ctx)
3108 {
3109 }
3110 #endif /* !CONFIG_USER_STACKTRACE_SUPPORT */
3111
3112 #endif /* CONFIG_STACKTRACE */
3113
3114 static inline void
func_repeats_set_delta_ts(struct func_repeats_entry * entry,unsigned long long delta)3115 func_repeats_set_delta_ts(struct func_repeats_entry *entry,
3116 unsigned long long delta)
3117 {
3118 entry->bottom_delta_ts = delta & U32_MAX;
3119 entry->top_delta_ts = (delta >> 32);
3120 }
3121
trace_last_func_repeats(struct trace_array * tr,struct trace_func_repeats * last_info,unsigned int trace_ctx)3122 void trace_last_func_repeats(struct trace_array *tr,
3123 struct trace_func_repeats *last_info,
3124 unsigned int trace_ctx)
3125 {
3126 struct trace_buffer *buffer = tr->array_buffer.buffer;
3127 struct func_repeats_entry *entry;
3128 struct ring_buffer_event *event;
3129 u64 delta;
3130
3131 event = __trace_buffer_lock_reserve(buffer, TRACE_FUNC_REPEATS,
3132 sizeof(*entry), trace_ctx);
3133 if (!event)
3134 return;
3135
3136 delta = ring_buffer_event_time_stamp(buffer, event) -
3137 last_info->ts_last_call;
3138
3139 entry = ring_buffer_event_data(event);
3140 entry->ip = last_info->ip;
3141 entry->parent_ip = last_info->parent_ip;
3142 entry->count = last_info->count;
3143 func_repeats_set_delta_ts(entry, delta);
3144
3145 __buffer_unlock_commit(buffer, event);
3146 }
3147
3148 /* created for use with alloc_percpu */
3149 struct trace_buffer_struct {
3150 int nesting;
3151 char buffer[4][TRACE_BUF_SIZE];
3152 };
3153
3154 static struct trace_buffer_struct __percpu *trace_percpu_buffer;
3155
3156 /*
3157 * This allows for lockless recording. If we're nested too deeply, then
3158 * this returns NULL.
3159 */
get_trace_buf(void)3160 static char *get_trace_buf(void)
3161 {
3162 struct trace_buffer_struct *buffer = this_cpu_ptr(trace_percpu_buffer);
3163
3164 if (!trace_percpu_buffer || buffer->nesting >= 4)
3165 return NULL;
3166
3167 buffer->nesting++;
3168
3169 /* Interrupts must see nesting incremented before we use the buffer */
3170 barrier();
3171 return &buffer->buffer[buffer->nesting - 1][0];
3172 }
3173
put_trace_buf(void)3174 static void put_trace_buf(void)
3175 {
3176 /* Don't let the decrement of nesting leak before this */
3177 barrier();
3178 this_cpu_dec(trace_percpu_buffer->nesting);
3179 }
3180
alloc_percpu_trace_buffer(void)3181 static int alloc_percpu_trace_buffer(void)
3182 {
3183 struct trace_buffer_struct __percpu *buffers;
3184
3185 if (trace_percpu_buffer)
3186 return 0;
3187
3188 buffers = alloc_percpu(struct trace_buffer_struct);
3189 if (MEM_FAIL(!buffers, "Could not allocate percpu trace_printk buffer"))
3190 return -ENOMEM;
3191
3192 trace_percpu_buffer = buffers;
3193 return 0;
3194 }
3195
3196 static int buffers_allocated;
3197
trace_printk_init_buffers(void)3198 void trace_printk_init_buffers(void)
3199 {
3200 if (buffers_allocated)
3201 return;
3202
3203 if (alloc_percpu_trace_buffer())
3204 return;
3205
3206 /* trace_printk() is for debug use only. Don't use it in production. */
3207
3208 pr_warn("\n");
3209 pr_warn("**********************************************************\n");
3210 pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
3211 pr_warn("** **\n");
3212 pr_warn("** trace_printk() being used. Allocating extra memory. **\n");
3213 pr_warn("** **\n");
3214 pr_warn("** This means that this is a DEBUG kernel and it is **\n");
3215 pr_warn("** unsafe for production use. **\n");
3216 pr_warn("** **\n");
3217 pr_warn("** If you see this message and you are not debugging **\n");
3218 pr_warn("** the kernel, report this immediately to your vendor! **\n");
3219 pr_warn("** **\n");
3220 pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
3221 pr_warn("**********************************************************\n");
3222
3223 /* Expand the buffers to set size */
3224 tracing_update_buffers(&global_trace);
3225
3226 buffers_allocated = 1;
3227
3228 /*
3229 * trace_printk_init_buffers() can be called by modules.
3230 * If that happens, then we need to start cmdline recording
3231 * directly here. If the global_trace.buffer is already
3232 * allocated here, then this was called by module code.
3233 */
3234 if (global_trace.array_buffer.buffer)
3235 tracing_start_cmdline_record();
3236 }
3237 EXPORT_SYMBOL_GPL(trace_printk_init_buffers);
3238
trace_printk_start_comm(void)3239 void trace_printk_start_comm(void)
3240 {
3241 /* Start tracing comms if trace printk is set */
3242 if (!buffers_allocated)
3243 return;
3244 tracing_start_cmdline_record();
3245 }
3246
trace_printk_start_stop_comm(int enabled)3247 static void trace_printk_start_stop_comm(int enabled)
3248 {
3249 if (!buffers_allocated)
3250 return;
3251
3252 if (enabled)
3253 tracing_start_cmdline_record();
3254 else
3255 tracing_stop_cmdline_record();
3256 }
3257
3258 /**
3259 * trace_vbprintk - write binary msg to tracing buffer
3260 * @ip: The address of the caller
3261 * @fmt: The string format to write to the buffer
3262 * @args: Arguments for @fmt
3263 */
trace_vbprintk(unsigned long ip,const char * fmt,va_list args)3264 int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
3265 {
3266 struct ring_buffer_event *event;
3267 struct trace_buffer *buffer;
3268 struct trace_array *tr = READ_ONCE(printk_trace);
3269 struct bprint_entry *entry;
3270 unsigned int trace_ctx;
3271 char *tbuffer;
3272 int len = 0, size;
3273
3274 if (!printk_binsafe(tr))
3275 return trace_vprintk(ip, fmt, args);
3276
3277 if (unlikely(tracing_selftest_running || tracing_disabled))
3278 return 0;
3279
3280 /* Don't pollute graph traces with trace_vprintk internals */
3281 pause_graph_tracing();
3282
3283 trace_ctx = tracing_gen_ctx();
3284 preempt_disable_notrace();
3285
3286 tbuffer = get_trace_buf();
3287 if (!tbuffer) {
3288 len = 0;
3289 goto out_nobuffer;
3290 }
3291
3292 len = vbin_printf((u32 *)tbuffer, TRACE_BUF_SIZE/sizeof(int), fmt, args);
3293
3294 if (len > TRACE_BUF_SIZE/sizeof(int) || len < 0)
3295 goto out_put;
3296
3297 size = sizeof(*entry) + sizeof(u32) * len;
3298 buffer = tr->array_buffer.buffer;
3299 ring_buffer_nest_start(buffer);
3300 event = __trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
3301 trace_ctx);
3302 if (!event)
3303 goto out;
3304 entry = ring_buffer_event_data(event);
3305 entry->ip = ip;
3306 entry->fmt = fmt;
3307
3308 memcpy(entry->buf, tbuffer, sizeof(u32) * len);
3309 __buffer_unlock_commit(buffer, event);
3310 ftrace_trace_stack(tr, buffer, trace_ctx, 6, NULL);
3311
3312 out:
3313 ring_buffer_nest_end(buffer);
3314 out_put:
3315 put_trace_buf();
3316
3317 out_nobuffer:
3318 preempt_enable_notrace();
3319 unpause_graph_tracing();
3320
3321 return len;
3322 }
3323 EXPORT_SYMBOL_GPL(trace_vbprintk);
3324
3325 __printf(3, 0)
3326 static int
__trace_array_vprintk(struct trace_buffer * buffer,unsigned long ip,const char * fmt,va_list args)3327 __trace_array_vprintk(struct trace_buffer *buffer,
3328 unsigned long ip, const char *fmt, va_list args)
3329 {
3330 struct ring_buffer_event *event;
3331 int len = 0, size;
3332 struct print_entry *entry;
3333 unsigned int trace_ctx;
3334 char *tbuffer;
3335
3336 if (tracing_disabled)
3337 return 0;
3338
3339 /* Don't pollute graph traces with trace_vprintk internals */
3340 pause_graph_tracing();
3341
3342 trace_ctx = tracing_gen_ctx();
3343 preempt_disable_notrace();
3344
3345
3346 tbuffer = get_trace_buf();
3347 if (!tbuffer) {
3348 len = 0;
3349 goto out_nobuffer;
3350 }
3351
3352 len = vscnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args);
3353
3354 size = sizeof(*entry) + len + 1;
3355 ring_buffer_nest_start(buffer);
3356 event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
3357 trace_ctx);
3358 if (!event)
3359 goto out;
3360 entry = ring_buffer_event_data(event);
3361 entry->ip = ip;
3362
3363 memcpy(&entry->buf, tbuffer, len + 1);
3364 __buffer_unlock_commit(buffer, event);
3365 ftrace_trace_stack(printk_trace, buffer, trace_ctx, 6, NULL);
3366
3367 out:
3368 ring_buffer_nest_end(buffer);
3369 put_trace_buf();
3370
3371 out_nobuffer:
3372 preempt_enable_notrace();
3373 unpause_graph_tracing();
3374
3375 return len;
3376 }
3377
3378 __printf(3, 0)
trace_array_vprintk(struct trace_array * tr,unsigned long ip,const char * fmt,va_list args)3379 int trace_array_vprintk(struct trace_array *tr,
3380 unsigned long ip, const char *fmt, va_list args)
3381 {
3382 if (tracing_selftest_running && tr == &global_trace)
3383 return 0;
3384
3385 return __trace_array_vprintk(tr->array_buffer.buffer, ip, fmt, args);
3386 }
3387
3388 /**
3389 * trace_array_printk - Print a message to a specific instance
3390 * @tr: The instance trace_array descriptor
3391 * @ip: The instruction pointer that this is called from.
3392 * @fmt: The format to print (printf format)
3393 *
3394 * If a subsystem sets up its own instance, they have the right to
3395 * printk strings into their tracing instance buffer using this
3396 * function. Note, this function will not write into the top level
3397 * buffer (use trace_printk() for that), as writing into the top level
3398 * buffer should only have events that can be individually disabled.
3399 * trace_printk() is only used for debugging a kernel, and should not
3400 * be ever incorporated in normal use.
3401 *
3402 * trace_array_printk() can be used, as it will not add noise to the
3403 * top level tracing buffer.
3404 *
3405 * Note, trace_array_init_printk() must be called on @tr before this
3406 * can be used.
3407 */
3408 __printf(3, 0)
trace_array_printk(struct trace_array * tr,unsigned long ip,const char * fmt,...)3409 int trace_array_printk(struct trace_array *tr,
3410 unsigned long ip, const char *fmt, ...)
3411 {
3412 int ret;
3413 va_list ap;
3414
3415 if (!tr)
3416 return -ENOENT;
3417
3418 /* This is only allowed for created instances */
3419 if (tr == &global_trace)
3420 return 0;
3421
3422 if (!(tr->trace_flags & TRACE_ITER_PRINTK))
3423 return 0;
3424
3425 va_start(ap, fmt);
3426 ret = trace_array_vprintk(tr, ip, fmt, ap);
3427 va_end(ap);
3428 return ret;
3429 }
3430 EXPORT_SYMBOL_GPL(trace_array_printk);
3431
3432 /**
3433 * trace_array_init_printk - Initialize buffers for trace_array_printk()
3434 * @tr: The trace array to initialize the buffers for
3435 *
3436 * As trace_array_printk() only writes into instances, they are OK to
3437 * have in the kernel (unlike trace_printk()). This needs to be called
3438 * before trace_array_printk() can be used on a trace_array.
3439 */
trace_array_init_printk(struct trace_array * tr)3440 int trace_array_init_printk(struct trace_array *tr)
3441 {
3442 if (!tr)
3443 return -ENOENT;
3444
3445 /* This is only allowed for created instances */
3446 if (tr == &global_trace)
3447 return -EINVAL;
3448
3449 return alloc_percpu_trace_buffer();
3450 }
3451 EXPORT_SYMBOL_GPL(trace_array_init_printk);
3452
3453 __printf(3, 4)
trace_array_printk_buf(struct trace_buffer * buffer,unsigned long ip,const char * fmt,...)3454 int trace_array_printk_buf(struct trace_buffer *buffer,
3455 unsigned long ip, const char *fmt, ...)
3456 {
3457 int ret;
3458 va_list ap;
3459
3460 if (!(printk_trace->trace_flags & TRACE_ITER_PRINTK))
3461 return 0;
3462
3463 va_start(ap, fmt);
3464 ret = __trace_array_vprintk(buffer, ip, fmt, ap);
3465 va_end(ap);
3466 return ret;
3467 }
3468
3469 __printf(2, 0)
trace_vprintk(unsigned long ip,const char * fmt,va_list args)3470 int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
3471 {
3472 return trace_array_vprintk(printk_trace, ip, fmt, args);
3473 }
3474 EXPORT_SYMBOL_GPL(trace_vprintk);
3475
trace_iterator_increment(struct trace_iterator * iter)3476 static void trace_iterator_increment(struct trace_iterator *iter)
3477 {
3478 struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, iter->cpu);
3479
3480 iter->idx++;
3481 if (buf_iter)
3482 ring_buffer_iter_advance(buf_iter);
3483 }
3484
3485 static struct trace_entry *
peek_next_entry(struct trace_iterator * iter,int cpu,u64 * ts,unsigned long * lost_events)3486 peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts,
3487 unsigned long *lost_events)
3488 {
3489 struct ring_buffer_event *event;
3490 struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, cpu);
3491
3492 if (buf_iter) {
3493 event = ring_buffer_iter_peek(buf_iter, ts);
3494 if (lost_events)
3495 *lost_events = ring_buffer_iter_dropped(buf_iter) ?
3496 (unsigned long)-1 : 0;
3497 } else {
3498 event = ring_buffer_peek(iter->array_buffer->buffer, cpu, ts,
3499 lost_events);
3500 }
3501
3502 if (event) {
3503 iter->ent_size = ring_buffer_event_length(event);
3504 return ring_buffer_event_data(event);
3505 }
3506 iter->ent_size = 0;
3507 return NULL;
3508 }
3509
3510 static struct trace_entry *
__find_next_entry(struct trace_iterator * iter,int * ent_cpu,unsigned long * missing_events,u64 * ent_ts)3511 __find_next_entry(struct trace_iterator *iter, int *ent_cpu,
3512 unsigned long *missing_events, u64 *ent_ts)
3513 {
3514 struct trace_buffer *buffer = iter->array_buffer->buffer;
3515 struct trace_entry *ent, *next = NULL;
3516 unsigned long lost_events = 0, next_lost = 0;
3517 int cpu_file = iter->cpu_file;
3518 u64 next_ts = 0, ts;
3519 int next_cpu = -1;
3520 int next_size = 0;
3521 int cpu;
3522
3523 /*
3524 * If we are in a per_cpu trace file, don't bother by iterating over
3525 * all cpu and peek directly.
3526 */
3527 if (cpu_file > RING_BUFFER_ALL_CPUS) {
3528 if (ring_buffer_empty_cpu(buffer, cpu_file))
3529 return NULL;
3530 ent = peek_next_entry(iter, cpu_file, ent_ts, missing_events);
3531 if (ent_cpu)
3532 *ent_cpu = cpu_file;
3533
3534 return ent;
3535 }
3536
3537 for_each_tracing_cpu(cpu) {
3538
3539 if (ring_buffer_empty_cpu(buffer, cpu))
3540 continue;
3541
3542 ent = peek_next_entry(iter, cpu, &ts, &lost_events);
3543
3544 /*
3545 * Pick the entry with the smallest timestamp:
3546 */
3547 if (ent && (!next || ts < next_ts)) {
3548 next = ent;
3549 next_cpu = cpu;
3550 next_ts = ts;
3551 next_lost = lost_events;
3552 next_size = iter->ent_size;
3553 }
3554 }
3555
3556 iter->ent_size = next_size;
3557
3558 if (ent_cpu)
3559 *ent_cpu = next_cpu;
3560
3561 if (ent_ts)
3562 *ent_ts = next_ts;
3563
3564 if (missing_events)
3565 *missing_events = next_lost;
3566
3567 return next;
3568 }
3569
3570 #define STATIC_FMT_BUF_SIZE 128
3571 static char static_fmt_buf[STATIC_FMT_BUF_SIZE];
3572
trace_iter_expand_format(struct trace_iterator * iter)3573 char *trace_iter_expand_format(struct trace_iterator *iter)
3574 {
3575 char *tmp;
3576
3577 /*
3578 * iter->tr is NULL when used with tp_printk, which makes
3579 * this get called where it is not safe to call krealloc().
3580 */
3581 if (!iter->tr || iter->fmt == static_fmt_buf)
3582 return NULL;
3583
3584 tmp = krealloc(iter->fmt, iter->fmt_size + STATIC_FMT_BUF_SIZE,
3585 GFP_KERNEL);
3586 if (tmp) {
3587 iter->fmt_size += STATIC_FMT_BUF_SIZE;
3588 iter->fmt = tmp;
3589 }
3590
3591 return tmp;
3592 }
3593
3594 /* Returns true if the string is safe to dereference from an event */
trace_safe_str(struct trace_iterator * iter,const char * str)3595 static bool trace_safe_str(struct trace_iterator *iter, const char *str)
3596 {
3597 unsigned long addr = (unsigned long)str;
3598 struct trace_event *trace_event;
3599 struct trace_event_call *event;
3600
3601 /* OK if part of the event data */
3602 if ((addr >= (unsigned long)iter->ent) &&
3603 (addr < (unsigned long)iter->ent + iter->ent_size))
3604 return true;
3605
3606 /* OK if part of the temp seq buffer */
3607 if ((addr >= (unsigned long)iter->tmp_seq.buffer) &&
3608 (addr < (unsigned long)iter->tmp_seq.buffer + TRACE_SEQ_BUFFER_SIZE))
3609 return true;
3610
3611 /* Core rodata can not be freed */
3612 if (is_kernel_rodata(addr))
3613 return true;
3614
3615 if (trace_is_tracepoint_string(str))
3616 return true;
3617
3618 /*
3619 * Now this could be a module event, referencing core module
3620 * data, which is OK.
3621 */
3622 if (!iter->ent)
3623 return false;
3624
3625 trace_event = ftrace_find_event(iter->ent->type);
3626 if (!trace_event)
3627 return false;
3628
3629 event = container_of(trace_event, struct trace_event_call, event);
3630 if ((event->flags & TRACE_EVENT_FL_DYNAMIC) || !event->module)
3631 return false;
3632
3633 /* Would rather have rodata, but this will suffice */
3634 if (within_module_core(addr, event->module))
3635 return true;
3636
3637 return false;
3638 }
3639
3640 /**
3641 * ignore_event - Check dereferenced fields while writing to the seq buffer
3642 * @iter: The iterator that holds the seq buffer and the event being printed
3643 *
3644 * At boot up, test_event_printk() will flag any event that dereferences
3645 * a string with "%s" that does exist in the ring buffer. It may still
3646 * be valid, as the string may point to a static string in the kernel
3647 * rodata that never gets freed. But if the string pointer is pointing
3648 * to something that was allocated, there's a chance that it can be freed
3649 * by the time the user reads the trace. This would cause a bad memory
3650 * access by the kernel and possibly crash the system.
3651 *
3652 * This function will check if the event has any fields flagged as needing
3653 * to be checked at runtime and perform those checks.
3654 *
3655 * If it is found that a field is unsafe, it will write into the @iter->seq
3656 * a message stating what was found to be unsafe.
3657 *
3658 * @return: true if the event is unsafe and should be ignored,
3659 * false otherwise.
3660 */
ignore_event(struct trace_iterator * iter)3661 bool ignore_event(struct trace_iterator *iter)
3662 {
3663 struct ftrace_event_field *field;
3664 struct trace_event *trace_event;
3665 struct trace_event_call *event;
3666 struct list_head *head;
3667 struct trace_seq *seq;
3668 const void *ptr;
3669
3670 trace_event = ftrace_find_event(iter->ent->type);
3671
3672 seq = &iter->seq;
3673
3674 if (!trace_event) {
3675 trace_seq_printf(seq, "EVENT ID %d NOT FOUND?\n", iter->ent->type);
3676 return true;
3677 }
3678
3679 event = container_of(trace_event, struct trace_event_call, event);
3680 if (!(event->flags & TRACE_EVENT_FL_TEST_STR))
3681 return false;
3682
3683 head = trace_get_fields(event);
3684 if (!head) {
3685 trace_seq_printf(seq, "FIELDS FOR EVENT '%s' NOT FOUND?\n",
3686 trace_event_name(event));
3687 return true;
3688 }
3689
3690 /* Offsets are from the iter->ent that points to the raw event */
3691 ptr = iter->ent;
3692
3693 list_for_each_entry(field, head, link) {
3694 const char *str;
3695 bool good;
3696
3697 if (!field->needs_test)
3698 continue;
3699
3700 str = *(const char **)(ptr + field->offset);
3701
3702 good = trace_safe_str(iter, str);
3703
3704 /*
3705 * If you hit this warning, it is likely that the
3706 * trace event in question used %s on a string that
3707 * was saved at the time of the event, but may not be
3708 * around when the trace is read. Use __string(),
3709 * __assign_str() and __get_str() helpers in the TRACE_EVENT()
3710 * instead. See samples/trace_events/trace-events-sample.h
3711 * for reference.
3712 */
3713 if (WARN_ONCE(!good, "event '%s' has unsafe pointer field '%s'",
3714 trace_event_name(event), field->name)) {
3715 trace_seq_printf(seq, "EVENT %s: HAS UNSAFE POINTER FIELD '%s'\n",
3716 trace_event_name(event), field->name);
3717 return true;
3718 }
3719 }
3720 return false;
3721 }
3722
trace_event_format(struct trace_iterator * iter,const char * fmt)3723 const char *trace_event_format(struct trace_iterator *iter, const char *fmt)
3724 {
3725 const char *p, *new_fmt;
3726 char *q;
3727
3728 if (WARN_ON_ONCE(!fmt))
3729 return fmt;
3730
3731 if (!iter->tr || iter->tr->trace_flags & TRACE_ITER_HASH_PTR)
3732 return fmt;
3733
3734 p = fmt;
3735 new_fmt = q = iter->fmt;
3736 while (*p) {
3737 if (unlikely(q - new_fmt + 3 > iter->fmt_size)) {
3738 if (!trace_iter_expand_format(iter))
3739 return fmt;
3740
3741 q += iter->fmt - new_fmt;
3742 new_fmt = iter->fmt;
3743 }
3744
3745 *q++ = *p++;
3746
3747 /* Replace %p with %px */
3748 if (p[-1] == '%') {
3749 if (p[0] == '%') {
3750 *q++ = *p++;
3751 } else if (p[0] == 'p' && !isalnum(p[1])) {
3752 *q++ = *p++;
3753 *q++ = 'x';
3754 }
3755 }
3756 }
3757 *q = '\0';
3758
3759 return new_fmt;
3760 }
3761
3762 #define STATIC_TEMP_BUF_SIZE 128
3763 static char static_temp_buf[STATIC_TEMP_BUF_SIZE] __aligned(4);
3764
3765 /* Find the next real entry, without updating the iterator itself */
trace_find_next_entry(struct trace_iterator * iter,int * ent_cpu,u64 * ent_ts)3766 struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
3767 int *ent_cpu, u64 *ent_ts)
3768 {
3769 /* __find_next_entry will reset ent_size */
3770 int ent_size = iter->ent_size;
3771 struct trace_entry *entry;
3772
3773 /*
3774 * If called from ftrace_dump(), then the iter->temp buffer
3775 * will be the static_temp_buf and not created from kmalloc.
3776 * If the entry size is greater than the buffer, we can
3777 * not save it. Just return NULL in that case. This is only
3778 * used to add markers when two consecutive events' time
3779 * stamps have a large delta. See trace_print_lat_context()
3780 */
3781 if (iter->temp == static_temp_buf &&
3782 STATIC_TEMP_BUF_SIZE < ent_size)
3783 return NULL;
3784
3785 /*
3786 * The __find_next_entry() may call peek_next_entry(), which may
3787 * call ring_buffer_peek() that may make the contents of iter->ent
3788 * undefined. Need to copy iter->ent now.
3789 */
3790 if (iter->ent && iter->ent != iter->temp) {
3791 if ((!iter->temp || iter->temp_size < iter->ent_size) &&
3792 !WARN_ON_ONCE(iter->temp == static_temp_buf)) {
3793 void *temp;
3794 temp = kmalloc(iter->ent_size, GFP_KERNEL);
3795 if (!temp)
3796 return NULL;
3797 kfree(iter->temp);
3798 iter->temp = temp;
3799 iter->temp_size = iter->ent_size;
3800 }
3801 memcpy(iter->temp, iter->ent, iter->ent_size);
3802 iter->ent = iter->temp;
3803 }
3804 entry = __find_next_entry(iter, ent_cpu, NULL, ent_ts);
3805 /* Put back the original ent_size */
3806 iter->ent_size = ent_size;
3807
3808 return entry;
3809 }
3810
3811 /* Find the next real entry, and increment the iterator to the next entry */
trace_find_next_entry_inc(struct trace_iterator * iter)3812 void *trace_find_next_entry_inc(struct trace_iterator *iter)
3813 {
3814 iter->ent = __find_next_entry(iter, &iter->cpu,
3815 &iter->lost_events, &iter->ts);
3816
3817 if (iter->ent)
3818 trace_iterator_increment(iter);
3819
3820 return iter->ent ? iter : NULL;
3821 }
3822
trace_consume(struct trace_iterator * iter)3823 static void trace_consume(struct trace_iterator *iter)
3824 {
3825 ring_buffer_consume(iter->array_buffer->buffer, iter->cpu, &iter->ts,
3826 &iter->lost_events);
3827 }
3828
s_next(struct seq_file * m,void * v,loff_t * pos)3829 static void *s_next(struct seq_file *m, void *v, loff_t *pos)
3830 {
3831 struct trace_iterator *iter = m->private;
3832 int i = (int)*pos;
3833 void *ent;
3834
3835 WARN_ON_ONCE(iter->leftover);
3836
3837 (*pos)++;
3838
3839 /* can't go backwards */
3840 if (iter->idx > i)
3841 return NULL;
3842
3843 if (iter->idx < 0)
3844 ent = trace_find_next_entry_inc(iter);
3845 else
3846 ent = iter;
3847
3848 while (ent && iter->idx < i)
3849 ent = trace_find_next_entry_inc(iter);
3850
3851 iter->pos = *pos;
3852
3853 return ent;
3854 }
3855
tracing_iter_reset(struct trace_iterator * iter,int cpu)3856 void tracing_iter_reset(struct trace_iterator *iter, int cpu)
3857 {
3858 struct ring_buffer_iter *buf_iter;
3859 unsigned long entries = 0;
3860 u64 ts;
3861
3862 per_cpu_ptr(iter->array_buffer->data, cpu)->skipped_entries = 0;
3863
3864 buf_iter = trace_buffer_iter(iter, cpu);
3865 if (!buf_iter)
3866 return;
3867
3868 ring_buffer_iter_reset(buf_iter);
3869
3870 /*
3871 * We could have the case with the max latency tracers
3872 * that a reset never took place on a cpu. This is evident
3873 * by the timestamp being before the start of the buffer.
3874 */
3875 while (ring_buffer_iter_peek(buf_iter, &ts)) {
3876 if (ts >= iter->array_buffer->time_start)
3877 break;
3878 entries++;
3879 ring_buffer_iter_advance(buf_iter);
3880 /* This could be a big loop */
3881 cond_resched();
3882 }
3883
3884 per_cpu_ptr(iter->array_buffer->data, cpu)->skipped_entries = entries;
3885 }
3886
3887 /*
3888 * The current tracer is copied to avoid a global locking
3889 * all around.
3890 */
s_start(struct seq_file * m,loff_t * pos)3891 static void *s_start(struct seq_file *m, loff_t *pos)
3892 {
3893 struct trace_iterator *iter = m->private;
3894 struct trace_array *tr = iter->tr;
3895 int cpu_file = iter->cpu_file;
3896 void *p = NULL;
3897 loff_t l = 0;
3898 int cpu;
3899
3900 mutex_lock(&trace_types_lock);
3901 if (unlikely(tr->current_trace != iter->trace)) {
3902 /* Close iter->trace before switching to the new current tracer */
3903 if (iter->trace->close)
3904 iter->trace->close(iter);
3905 iter->trace = tr->current_trace;
3906 /* Reopen the new current tracer */
3907 if (iter->trace->open)
3908 iter->trace->open(iter);
3909 }
3910 mutex_unlock(&trace_types_lock);
3911
3912 #ifdef CONFIG_TRACER_MAX_TRACE
3913 if (iter->snapshot && iter->trace->use_max_tr)
3914 return ERR_PTR(-EBUSY);
3915 #endif
3916
3917 if (*pos != iter->pos) {
3918 iter->ent = NULL;
3919 iter->cpu = 0;
3920 iter->idx = -1;
3921
3922 if (cpu_file == RING_BUFFER_ALL_CPUS) {
3923 for_each_tracing_cpu(cpu)
3924 tracing_iter_reset(iter, cpu);
3925 } else
3926 tracing_iter_reset(iter, cpu_file);
3927
3928 iter->leftover = 0;
3929 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
3930 ;
3931
3932 } else {
3933 /*
3934 * If we overflowed the seq_file before, then we want
3935 * to just reuse the trace_seq buffer again.
3936 */
3937 if (iter->leftover)
3938 p = iter;
3939 else {
3940 l = *pos - 1;
3941 p = s_next(m, p, &l);
3942 }
3943 }
3944
3945 trace_event_read_lock();
3946 trace_access_lock(cpu_file);
3947 return p;
3948 }
3949
s_stop(struct seq_file * m,void * p)3950 static void s_stop(struct seq_file *m, void *p)
3951 {
3952 struct trace_iterator *iter = m->private;
3953
3954 #ifdef CONFIG_TRACER_MAX_TRACE
3955 if (iter->snapshot && iter->trace->use_max_tr)
3956 return;
3957 #endif
3958
3959 trace_access_unlock(iter->cpu_file);
3960 trace_event_read_unlock();
3961 }
3962
3963 static void
get_total_entries_cpu(struct array_buffer * buf,unsigned long * total,unsigned long * entries,int cpu)3964 get_total_entries_cpu(struct array_buffer *buf, unsigned long *total,
3965 unsigned long *entries, int cpu)
3966 {
3967 unsigned long count;
3968
3969 count = ring_buffer_entries_cpu(buf->buffer, cpu);
3970 /*
3971 * If this buffer has skipped entries, then we hold all
3972 * entries for the trace and we need to ignore the
3973 * ones before the time stamp.
3974 */
3975 if (per_cpu_ptr(buf->data, cpu)->skipped_entries) {
3976 count -= per_cpu_ptr(buf->data, cpu)->skipped_entries;
3977 /* total is the same as the entries */
3978 *total = count;
3979 } else
3980 *total = count +
3981 ring_buffer_overrun_cpu(buf->buffer, cpu);
3982 *entries = count;
3983 }
3984
3985 static void
get_total_entries(struct array_buffer * buf,unsigned long * total,unsigned long * entries)3986 get_total_entries(struct array_buffer *buf,
3987 unsigned long *total, unsigned long *entries)
3988 {
3989 unsigned long t, e;
3990 int cpu;
3991
3992 *total = 0;
3993 *entries = 0;
3994
3995 for_each_tracing_cpu(cpu) {
3996 get_total_entries_cpu(buf, &t, &e, cpu);
3997 *total += t;
3998 *entries += e;
3999 }
4000 }
4001
trace_total_entries_cpu(struct trace_array * tr,int cpu)4002 unsigned long trace_total_entries_cpu(struct trace_array *tr, int cpu)
4003 {
4004 unsigned long total, entries;
4005
4006 if (!tr)
4007 tr = &global_trace;
4008
4009 get_total_entries_cpu(&tr->array_buffer, &total, &entries, cpu);
4010
4011 return entries;
4012 }
4013
trace_total_entries(struct trace_array * tr)4014 unsigned long trace_total_entries(struct trace_array *tr)
4015 {
4016 unsigned long total, entries;
4017
4018 if (!tr)
4019 tr = &global_trace;
4020
4021 get_total_entries(&tr->array_buffer, &total, &entries);
4022
4023 return entries;
4024 }
4025
print_lat_help_header(struct seq_file * m)4026 static void print_lat_help_header(struct seq_file *m)
4027 {
4028 seq_puts(m, "# _------=> CPU# \n"
4029 "# / _-----=> irqs-off/BH-disabled\n"
4030 "# | / _----=> need-resched \n"
4031 "# || / _---=> hardirq/softirq \n"
4032 "# ||| / _--=> preempt-depth \n"
4033 "# |||| / _-=> migrate-disable \n"
4034 "# ||||| / delay \n"
4035 "# cmd pid |||||| time | caller \n"
4036 "# \\ / |||||| \\ | / \n");
4037 }
4038
print_event_info(struct array_buffer * buf,struct seq_file * m)4039 static void print_event_info(struct array_buffer *buf, struct seq_file *m)
4040 {
4041 unsigned long total;
4042 unsigned long entries;
4043
4044 get_total_entries(buf, &total, &entries);
4045 seq_printf(m, "# entries-in-buffer/entries-written: %lu/%lu #P:%d\n",
4046 entries, total, num_online_cpus());
4047 seq_puts(m, "#\n");
4048 }
4049
print_func_help_header(struct array_buffer * buf,struct seq_file * m,unsigned int flags)4050 static void print_func_help_header(struct array_buffer *buf, struct seq_file *m,
4051 unsigned int flags)
4052 {
4053 bool tgid = flags & TRACE_ITER_RECORD_TGID;
4054
4055 print_event_info(buf, m);
4056
4057 seq_printf(m, "# TASK-PID %s CPU# TIMESTAMP FUNCTION\n", tgid ? " TGID " : "");
4058 seq_printf(m, "# | | %s | | |\n", tgid ? " | " : "");
4059 }
4060
print_func_help_header_irq(struct array_buffer * buf,struct seq_file * m,unsigned int flags)4061 static void print_func_help_header_irq(struct array_buffer *buf, struct seq_file *m,
4062 unsigned int flags)
4063 {
4064 bool tgid = flags & TRACE_ITER_RECORD_TGID;
4065 static const char space[] = " ";
4066 int prec = tgid ? 12 : 2;
4067
4068 print_event_info(buf, m);
4069
4070 seq_printf(m, "# %.*s _-----=> irqs-off/BH-disabled\n", prec, space);
4071 seq_printf(m, "# %.*s / _----=> need-resched\n", prec, space);
4072 seq_printf(m, "# %.*s| / _---=> hardirq/softirq\n", prec, space);
4073 seq_printf(m, "# %.*s|| / _--=> preempt-depth\n", prec, space);
4074 seq_printf(m, "# %.*s||| / _-=> migrate-disable\n", prec, space);
4075 seq_printf(m, "# %.*s|||| / delay\n", prec, space);
4076 seq_printf(m, "# TASK-PID %.*s CPU# ||||| TIMESTAMP FUNCTION\n", prec, " TGID ");
4077 seq_printf(m, "# | | %.*s | ||||| | |\n", prec, " | ");
4078 }
4079
4080 void
print_trace_header(struct seq_file * m,struct trace_iterator * iter)4081 print_trace_header(struct seq_file *m, struct trace_iterator *iter)
4082 {
4083 unsigned long sym_flags = (global_trace.trace_flags & TRACE_ITER_SYM_MASK);
4084 struct array_buffer *buf = iter->array_buffer;
4085 struct trace_array_cpu *data = per_cpu_ptr(buf->data, buf->cpu);
4086 struct tracer *type = iter->trace;
4087 unsigned long entries;
4088 unsigned long total;
4089 const char *name = type->name;
4090
4091 get_total_entries(buf, &total, &entries);
4092
4093 seq_printf(m, "# %s latency trace v1.1.5 on %s\n",
4094 name, init_utsname()->release);
4095 seq_puts(m, "# -----------------------------------"
4096 "---------------------------------\n");
4097 seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d |"
4098 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
4099 nsecs_to_usecs(data->saved_latency),
4100 entries,
4101 total,
4102 buf->cpu,
4103 preempt_model_none() ? "server" :
4104 preempt_model_voluntary() ? "desktop" :
4105 preempt_model_full() ? "preempt" :
4106 preempt_model_lazy() ? "lazy" :
4107 preempt_model_rt() ? "preempt_rt" :
4108 "unknown",
4109 /* These are reserved for later use */
4110 0, 0, 0, 0);
4111 #ifdef CONFIG_SMP
4112 seq_printf(m, " #P:%d)\n", num_online_cpus());
4113 #else
4114 seq_puts(m, ")\n");
4115 #endif
4116 seq_puts(m, "# -----------------\n");
4117 seq_printf(m, "# | task: %.16s-%d "
4118 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
4119 data->comm, data->pid,
4120 from_kuid_munged(seq_user_ns(m), data->uid), data->nice,
4121 data->policy, data->rt_priority);
4122 seq_puts(m, "# -----------------\n");
4123
4124 if (data->critical_start) {
4125 seq_puts(m, "# => started at: ");
4126 seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
4127 trace_print_seq(m, &iter->seq);
4128 seq_puts(m, "\n# => ended at: ");
4129 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
4130 trace_print_seq(m, &iter->seq);
4131 seq_puts(m, "\n#\n");
4132 }
4133
4134 seq_puts(m, "#\n");
4135 }
4136
test_cpu_buff_start(struct trace_iterator * iter)4137 static void test_cpu_buff_start(struct trace_iterator *iter)
4138 {
4139 struct trace_seq *s = &iter->seq;
4140 struct trace_array *tr = iter->tr;
4141
4142 if (!(tr->trace_flags & TRACE_ITER_ANNOTATE))
4143 return;
4144
4145 if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
4146 return;
4147
4148 if (cpumask_available(iter->started) &&
4149 cpumask_test_cpu(iter->cpu, iter->started))
4150 return;
4151
4152 if (per_cpu_ptr(iter->array_buffer->data, iter->cpu)->skipped_entries)
4153 return;
4154
4155 if (cpumask_available(iter->started))
4156 cpumask_set_cpu(iter->cpu, iter->started);
4157
4158 /* Don't print started cpu buffer for the first entry of the trace */
4159 if (iter->idx > 1)
4160 trace_seq_printf(s, "##### CPU %u buffer started ####\n",
4161 iter->cpu);
4162 }
4163
print_trace_fmt(struct trace_iterator * iter)4164 static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
4165 {
4166 struct trace_array *tr = iter->tr;
4167 struct trace_seq *s = &iter->seq;
4168 unsigned long sym_flags = (tr->trace_flags & TRACE_ITER_SYM_MASK);
4169 struct trace_entry *entry;
4170 struct trace_event *event;
4171
4172 entry = iter->ent;
4173
4174 test_cpu_buff_start(iter);
4175
4176 event = ftrace_find_event(entry->type);
4177
4178 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
4179 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
4180 trace_print_lat_context(iter);
4181 else
4182 trace_print_context(iter);
4183 }
4184
4185 if (trace_seq_has_overflowed(s))
4186 return TRACE_TYPE_PARTIAL_LINE;
4187
4188 if (event) {
4189 if (tr->trace_flags & TRACE_ITER_FIELDS)
4190 return print_event_fields(iter, event);
4191 /*
4192 * For TRACE_EVENT() events, the print_fmt is not
4193 * safe to use if the array has delta offsets
4194 * Force printing via the fields.
4195 */
4196 if ((tr->text_delta || tr->data_delta) &&
4197 event->type > __TRACE_LAST_TYPE)
4198 return print_event_fields(iter, event);
4199
4200 return event->funcs->trace(iter, sym_flags, event);
4201 }
4202
4203 trace_seq_printf(s, "Unknown type %d\n", entry->type);
4204
4205 return trace_handle_return(s);
4206 }
4207
print_raw_fmt(struct trace_iterator * iter)4208 static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
4209 {
4210 struct trace_array *tr = iter->tr;
4211 struct trace_seq *s = &iter->seq;
4212 struct trace_entry *entry;
4213 struct trace_event *event;
4214
4215 entry = iter->ent;
4216
4217 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO)
4218 trace_seq_printf(s, "%d %d %llu ",
4219 entry->pid, iter->cpu, iter->ts);
4220
4221 if (trace_seq_has_overflowed(s))
4222 return TRACE_TYPE_PARTIAL_LINE;
4223
4224 event = ftrace_find_event(entry->type);
4225 if (event)
4226 return event->funcs->raw(iter, 0, event);
4227
4228 trace_seq_printf(s, "%d ?\n", entry->type);
4229
4230 return trace_handle_return(s);
4231 }
4232
print_hex_fmt(struct trace_iterator * iter)4233 static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
4234 {
4235 struct trace_array *tr = iter->tr;
4236 struct trace_seq *s = &iter->seq;
4237 unsigned char newline = '\n';
4238 struct trace_entry *entry;
4239 struct trace_event *event;
4240
4241 entry = iter->ent;
4242
4243 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
4244 SEQ_PUT_HEX_FIELD(s, entry->pid);
4245 SEQ_PUT_HEX_FIELD(s, iter->cpu);
4246 SEQ_PUT_HEX_FIELD(s, iter->ts);
4247 if (trace_seq_has_overflowed(s))
4248 return TRACE_TYPE_PARTIAL_LINE;
4249 }
4250
4251 event = ftrace_find_event(entry->type);
4252 if (event) {
4253 enum print_line_t ret = event->funcs->hex(iter, 0, event);
4254 if (ret != TRACE_TYPE_HANDLED)
4255 return ret;
4256 }
4257
4258 SEQ_PUT_FIELD(s, newline);
4259
4260 return trace_handle_return(s);
4261 }
4262
print_bin_fmt(struct trace_iterator * iter)4263 static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
4264 {
4265 struct trace_array *tr = iter->tr;
4266 struct trace_seq *s = &iter->seq;
4267 struct trace_entry *entry;
4268 struct trace_event *event;
4269
4270 entry = iter->ent;
4271
4272 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
4273 SEQ_PUT_FIELD(s, entry->pid);
4274 SEQ_PUT_FIELD(s, iter->cpu);
4275 SEQ_PUT_FIELD(s, iter->ts);
4276 if (trace_seq_has_overflowed(s))
4277 return TRACE_TYPE_PARTIAL_LINE;
4278 }
4279
4280 event = ftrace_find_event(entry->type);
4281 return event ? event->funcs->binary(iter, 0, event) :
4282 TRACE_TYPE_HANDLED;
4283 }
4284
trace_empty(struct trace_iterator * iter)4285 int trace_empty(struct trace_iterator *iter)
4286 {
4287 struct ring_buffer_iter *buf_iter;
4288 int cpu;
4289
4290 /* If we are looking at one CPU buffer, only check that one */
4291 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
4292 cpu = iter->cpu_file;
4293 buf_iter = trace_buffer_iter(iter, cpu);
4294 if (buf_iter) {
4295 if (!ring_buffer_iter_empty(buf_iter))
4296 return 0;
4297 } else {
4298 if (!ring_buffer_empty_cpu(iter->array_buffer->buffer, cpu))
4299 return 0;
4300 }
4301 return 1;
4302 }
4303
4304 for_each_tracing_cpu(cpu) {
4305 buf_iter = trace_buffer_iter(iter, cpu);
4306 if (buf_iter) {
4307 if (!ring_buffer_iter_empty(buf_iter))
4308 return 0;
4309 } else {
4310 if (!ring_buffer_empty_cpu(iter->array_buffer->buffer, cpu))
4311 return 0;
4312 }
4313 }
4314
4315 return 1;
4316 }
4317
4318 /* Called with trace_event_read_lock() held. */
print_trace_line(struct trace_iterator * iter)4319 enum print_line_t print_trace_line(struct trace_iterator *iter)
4320 {
4321 struct trace_array *tr = iter->tr;
4322 unsigned long trace_flags = tr->trace_flags;
4323 enum print_line_t ret;
4324
4325 if (iter->lost_events) {
4326 if (iter->lost_events == (unsigned long)-1)
4327 trace_seq_printf(&iter->seq, "CPU:%d [LOST EVENTS]\n",
4328 iter->cpu);
4329 else
4330 trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
4331 iter->cpu, iter->lost_events);
4332 if (trace_seq_has_overflowed(&iter->seq))
4333 return TRACE_TYPE_PARTIAL_LINE;
4334 }
4335
4336 if (iter->trace && iter->trace->print_line) {
4337 ret = iter->trace->print_line(iter);
4338 if (ret != TRACE_TYPE_UNHANDLED)
4339 return ret;
4340 }
4341
4342 if (iter->ent->type == TRACE_BPUTS &&
4343 trace_flags & TRACE_ITER_PRINTK &&
4344 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
4345 return trace_print_bputs_msg_only(iter);
4346
4347 if (iter->ent->type == TRACE_BPRINT &&
4348 trace_flags & TRACE_ITER_PRINTK &&
4349 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
4350 return trace_print_bprintk_msg_only(iter);
4351
4352 if (iter->ent->type == TRACE_PRINT &&
4353 trace_flags & TRACE_ITER_PRINTK &&
4354 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
4355 return trace_print_printk_msg_only(iter);
4356
4357 if (trace_flags & TRACE_ITER_BIN)
4358 return print_bin_fmt(iter);
4359
4360 if (trace_flags & TRACE_ITER_HEX)
4361 return print_hex_fmt(iter);
4362
4363 if (trace_flags & TRACE_ITER_RAW)
4364 return print_raw_fmt(iter);
4365
4366 return print_trace_fmt(iter);
4367 }
4368
trace_latency_header(struct seq_file * m)4369 void trace_latency_header(struct seq_file *m)
4370 {
4371 struct trace_iterator *iter = m->private;
4372 struct trace_array *tr = iter->tr;
4373
4374 /* print nothing if the buffers are empty */
4375 if (trace_empty(iter))
4376 return;
4377
4378 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
4379 print_trace_header(m, iter);
4380
4381 if (!(tr->trace_flags & TRACE_ITER_VERBOSE))
4382 print_lat_help_header(m);
4383 }
4384
trace_default_header(struct seq_file * m)4385 void trace_default_header(struct seq_file *m)
4386 {
4387 struct trace_iterator *iter = m->private;
4388 struct trace_array *tr = iter->tr;
4389 unsigned long trace_flags = tr->trace_flags;
4390
4391 if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
4392 return;
4393
4394 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
4395 /* print nothing if the buffers are empty */
4396 if (trace_empty(iter))
4397 return;
4398 print_trace_header(m, iter);
4399 if (!(trace_flags & TRACE_ITER_VERBOSE))
4400 print_lat_help_header(m);
4401 } else {
4402 if (!(trace_flags & TRACE_ITER_VERBOSE)) {
4403 if (trace_flags & TRACE_ITER_IRQ_INFO)
4404 print_func_help_header_irq(iter->array_buffer,
4405 m, trace_flags);
4406 else
4407 print_func_help_header(iter->array_buffer, m,
4408 trace_flags);
4409 }
4410 }
4411 }
4412
test_ftrace_alive(struct seq_file * m)4413 static void test_ftrace_alive(struct seq_file *m)
4414 {
4415 if (!ftrace_is_dead())
4416 return;
4417 seq_puts(m, "# WARNING: FUNCTION TRACING IS CORRUPTED\n"
4418 "# MAY BE MISSING FUNCTION EVENTS\n");
4419 }
4420
4421 #ifdef CONFIG_TRACER_MAX_TRACE
show_snapshot_main_help(struct seq_file * m)4422 static void show_snapshot_main_help(struct seq_file *m)
4423 {
4424 seq_puts(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n"
4425 "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
4426 "# Takes a snapshot of the main buffer.\n"
4427 "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate or free)\n"
4428 "# (Doesn't have to be '2' works with any number that\n"
4429 "# is not a '0' or '1')\n");
4430 }
4431
show_snapshot_percpu_help(struct seq_file * m)4432 static void show_snapshot_percpu_help(struct seq_file *m)
4433 {
4434 seq_puts(m, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n");
4435 #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
4436 seq_puts(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
4437 "# Takes a snapshot of the main buffer for this cpu.\n");
4438 #else
4439 seq_puts(m, "# echo 1 > snapshot : Not supported with this kernel.\n"
4440 "# Must use main snapshot file to allocate.\n");
4441 #endif
4442 seq_puts(m, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n"
4443 "# (Doesn't have to be '2' works with any number that\n"
4444 "# is not a '0' or '1')\n");
4445 }
4446
print_snapshot_help(struct seq_file * m,struct trace_iterator * iter)4447 static void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter)
4448 {
4449 if (iter->tr->allocated_snapshot)
4450 seq_puts(m, "#\n# * Snapshot is allocated *\n#\n");
4451 else
4452 seq_puts(m, "#\n# * Snapshot is freed *\n#\n");
4453
4454 seq_puts(m, "# Snapshot commands:\n");
4455 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
4456 show_snapshot_main_help(m);
4457 else
4458 show_snapshot_percpu_help(m);
4459 }
4460 #else
4461 /* Should never be called */
print_snapshot_help(struct seq_file * m,struct trace_iterator * iter)4462 static inline void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter) { }
4463 #endif
4464
s_show(struct seq_file * m,void * v)4465 static int s_show(struct seq_file *m, void *v)
4466 {
4467 struct trace_iterator *iter = v;
4468 int ret;
4469
4470 if (iter->ent == NULL) {
4471 if (iter->tr) {
4472 seq_printf(m, "# tracer: %s\n", iter->trace->name);
4473 seq_puts(m, "#\n");
4474 test_ftrace_alive(m);
4475 }
4476 if (iter->snapshot && trace_empty(iter))
4477 print_snapshot_help(m, iter);
4478 else if (iter->trace && iter->trace->print_header)
4479 iter->trace->print_header(m);
4480 else
4481 trace_default_header(m);
4482
4483 } else if (iter->leftover) {
4484 /*
4485 * If we filled the seq_file buffer earlier, we
4486 * want to just show it now.
4487 */
4488 ret = trace_print_seq(m, &iter->seq);
4489
4490 /* ret should this time be zero, but you never know */
4491 iter->leftover = ret;
4492
4493 } else {
4494 ret = print_trace_line(iter);
4495 if (ret == TRACE_TYPE_PARTIAL_LINE) {
4496 iter->seq.full = 0;
4497 trace_seq_puts(&iter->seq, "[LINE TOO BIG]\n");
4498 }
4499 ret = trace_print_seq(m, &iter->seq);
4500 /*
4501 * If we overflow the seq_file buffer, then it will
4502 * ask us for this data again at start up.
4503 * Use that instead.
4504 * ret is 0 if seq_file write succeeded.
4505 * -1 otherwise.
4506 */
4507 iter->leftover = ret;
4508 }
4509
4510 return 0;
4511 }
4512
4513 /*
4514 * Should be used after trace_array_get(), trace_types_lock
4515 * ensures that i_cdev was already initialized.
4516 */
tracing_get_cpu(struct inode * inode)4517 static inline int tracing_get_cpu(struct inode *inode)
4518 {
4519 if (inode->i_cdev) /* See trace_create_cpu_file() */
4520 return (long)inode->i_cdev - 1;
4521 return RING_BUFFER_ALL_CPUS;
4522 }
4523
4524 static const struct seq_operations tracer_seq_ops = {
4525 .start = s_start,
4526 .next = s_next,
4527 .stop = s_stop,
4528 .show = s_show,
4529 };
4530
4531 /*
4532 * Note, as iter itself can be allocated and freed in different
4533 * ways, this function is only used to free its content, and not
4534 * the iterator itself. The only requirement to all the allocations
4535 * is that it must zero all fields (kzalloc), as freeing works with
4536 * ethier allocated content or NULL.
4537 */
free_trace_iter_content(struct trace_iterator * iter)4538 static void free_trace_iter_content(struct trace_iterator *iter)
4539 {
4540 /* The fmt is either NULL, allocated or points to static_fmt_buf */
4541 if (iter->fmt != static_fmt_buf)
4542 kfree(iter->fmt);
4543
4544 kfree(iter->temp);
4545 kfree(iter->buffer_iter);
4546 mutex_destroy(&iter->mutex);
4547 free_cpumask_var(iter->started);
4548 }
4549
4550 static struct trace_iterator *
__tracing_open(struct inode * inode,struct file * file,bool snapshot)4551 __tracing_open(struct inode *inode, struct file *file, bool snapshot)
4552 {
4553 struct trace_array *tr = inode->i_private;
4554 struct trace_iterator *iter;
4555 int cpu;
4556
4557 if (tracing_disabled)
4558 return ERR_PTR(-ENODEV);
4559
4560 iter = __seq_open_private(file, &tracer_seq_ops, sizeof(*iter));
4561 if (!iter)
4562 return ERR_PTR(-ENOMEM);
4563
4564 iter->buffer_iter = kcalloc(nr_cpu_ids, sizeof(*iter->buffer_iter),
4565 GFP_KERNEL);
4566 if (!iter->buffer_iter)
4567 goto release;
4568
4569 /*
4570 * trace_find_next_entry() may need to save off iter->ent.
4571 * It will place it into the iter->temp buffer. As most
4572 * events are less than 128, allocate a buffer of that size.
4573 * If one is greater, then trace_find_next_entry() will
4574 * allocate a new buffer to adjust for the bigger iter->ent.
4575 * It's not critical if it fails to get allocated here.
4576 */
4577 iter->temp = kmalloc(128, GFP_KERNEL);
4578 if (iter->temp)
4579 iter->temp_size = 128;
4580
4581 /*
4582 * trace_event_printf() may need to modify given format
4583 * string to replace %p with %px so that it shows real address
4584 * instead of hash value. However, that is only for the event
4585 * tracing, other tracer may not need. Defer the allocation
4586 * until it is needed.
4587 */
4588 iter->fmt = NULL;
4589 iter->fmt_size = 0;
4590
4591 mutex_lock(&trace_types_lock);
4592 iter->trace = tr->current_trace;
4593
4594 if (!zalloc_cpumask_var(&iter->started, GFP_KERNEL))
4595 goto fail;
4596
4597 iter->tr = tr;
4598
4599 #ifdef CONFIG_TRACER_MAX_TRACE
4600 /* Currently only the top directory has a snapshot */
4601 if (tr->current_trace->print_max || snapshot)
4602 iter->array_buffer = &tr->max_buffer;
4603 else
4604 #endif
4605 iter->array_buffer = &tr->array_buffer;
4606 iter->snapshot = snapshot;
4607 iter->pos = -1;
4608 iter->cpu_file = tracing_get_cpu(inode);
4609 mutex_init(&iter->mutex);
4610
4611 /* Notify the tracer early; before we stop tracing. */
4612 if (iter->trace->open)
4613 iter->trace->open(iter);
4614
4615 /* Annotate start of buffers if we had overruns */
4616 if (ring_buffer_overruns(iter->array_buffer->buffer))
4617 iter->iter_flags |= TRACE_FILE_ANNOTATE;
4618
4619 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
4620 if (trace_clocks[tr->clock_id].in_ns)
4621 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
4622
4623 /*
4624 * If pause-on-trace is enabled, then stop the trace while
4625 * dumping, unless this is the "snapshot" file
4626 */
4627 if (!iter->snapshot && (tr->trace_flags & TRACE_ITER_PAUSE_ON_TRACE))
4628 tracing_stop_tr(tr);
4629
4630 if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
4631 for_each_tracing_cpu(cpu) {
4632 iter->buffer_iter[cpu] =
4633 ring_buffer_read_prepare(iter->array_buffer->buffer,
4634 cpu, GFP_KERNEL);
4635 }
4636 ring_buffer_read_prepare_sync();
4637 for_each_tracing_cpu(cpu) {
4638 ring_buffer_read_start(iter->buffer_iter[cpu]);
4639 tracing_iter_reset(iter, cpu);
4640 }
4641 } else {
4642 cpu = iter->cpu_file;
4643 iter->buffer_iter[cpu] =
4644 ring_buffer_read_prepare(iter->array_buffer->buffer,
4645 cpu, GFP_KERNEL);
4646 ring_buffer_read_prepare_sync();
4647 ring_buffer_read_start(iter->buffer_iter[cpu]);
4648 tracing_iter_reset(iter, cpu);
4649 }
4650
4651 mutex_unlock(&trace_types_lock);
4652
4653 return iter;
4654
4655 fail:
4656 mutex_unlock(&trace_types_lock);
4657 free_trace_iter_content(iter);
4658 release:
4659 seq_release_private(inode, file);
4660 return ERR_PTR(-ENOMEM);
4661 }
4662
tracing_open_generic(struct inode * inode,struct file * filp)4663 int tracing_open_generic(struct inode *inode, struct file *filp)
4664 {
4665 int ret;
4666
4667 ret = tracing_check_open_get_tr(NULL);
4668 if (ret)
4669 return ret;
4670
4671 filp->private_data = inode->i_private;
4672 return 0;
4673 }
4674
tracing_is_disabled(void)4675 bool tracing_is_disabled(void)
4676 {
4677 return (tracing_disabled) ? true: false;
4678 }
4679
4680 /*
4681 * Open and update trace_array ref count.
4682 * Must have the current trace_array passed to it.
4683 */
tracing_open_generic_tr(struct inode * inode,struct file * filp)4684 int tracing_open_generic_tr(struct inode *inode, struct file *filp)
4685 {
4686 struct trace_array *tr = inode->i_private;
4687 int ret;
4688
4689 ret = tracing_check_open_get_tr(tr);
4690 if (ret)
4691 return ret;
4692
4693 filp->private_data = inode->i_private;
4694
4695 return 0;
4696 }
4697
4698 /*
4699 * The private pointer of the inode is the trace_event_file.
4700 * Update the tr ref count associated to it.
4701 */
tracing_open_file_tr(struct inode * inode,struct file * filp)4702 int tracing_open_file_tr(struct inode *inode, struct file *filp)
4703 {
4704 struct trace_event_file *file = inode->i_private;
4705 int ret;
4706
4707 ret = tracing_check_open_get_tr(file->tr);
4708 if (ret)
4709 return ret;
4710
4711 mutex_lock(&event_mutex);
4712
4713 /* Fail if the file is marked for removal */
4714 if (file->flags & EVENT_FILE_FL_FREED) {
4715 trace_array_put(file->tr);
4716 ret = -ENODEV;
4717 } else {
4718 event_file_get(file);
4719 }
4720
4721 mutex_unlock(&event_mutex);
4722 if (ret)
4723 return ret;
4724
4725 filp->private_data = inode->i_private;
4726
4727 return 0;
4728 }
4729
tracing_release_file_tr(struct inode * inode,struct file * filp)4730 int tracing_release_file_tr(struct inode *inode, struct file *filp)
4731 {
4732 struct trace_event_file *file = inode->i_private;
4733
4734 trace_array_put(file->tr);
4735 event_file_put(file);
4736
4737 return 0;
4738 }
4739
tracing_single_release_file_tr(struct inode * inode,struct file * filp)4740 int tracing_single_release_file_tr(struct inode *inode, struct file *filp)
4741 {
4742 tracing_release_file_tr(inode, filp);
4743 return single_release(inode, filp);
4744 }
4745
tracing_mark_open(struct inode * inode,struct file * filp)4746 static int tracing_mark_open(struct inode *inode, struct file *filp)
4747 {
4748 stream_open(inode, filp);
4749 return tracing_open_generic_tr(inode, filp);
4750 }
4751
tracing_release(struct inode * inode,struct file * file)4752 static int tracing_release(struct inode *inode, struct file *file)
4753 {
4754 struct trace_array *tr = inode->i_private;
4755 struct seq_file *m = file->private_data;
4756 struct trace_iterator *iter;
4757 int cpu;
4758
4759 if (!(file->f_mode & FMODE_READ)) {
4760 trace_array_put(tr);
4761 return 0;
4762 }
4763
4764 /* Writes do not use seq_file */
4765 iter = m->private;
4766 mutex_lock(&trace_types_lock);
4767
4768 for_each_tracing_cpu(cpu) {
4769 if (iter->buffer_iter[cpu])
4770 ring_buffer_read_finish(iter->buffer_iter[cpu]);
4771 }
4772
4773 if (iter->trace && iter->trace->close)
4774 iter->trace->close(iter);
4775
4776 if (!iter->snapshot && tr->stop_count)
4777 /* reenable tracing if it was previously enabled */
4778 tracing_start_tr(tr);
4779
4780 __trace_array_put(tr);
4781
4782 mutex_unlock(&trace_types_lock);
4783
4784 free_trace_iter_content(iter);
4785 seq_release_private(inode, file);
4786
4787 return 0;
4788 }
4789
tracing_release_generic_tr(struct inode * inode,struct file * file)4790 int tracing_release_generic_tr(struct inode *inode, struct file *file)
4791 {
4792 struct trace_array *tr = inode->i_private;
4793
4794 trace_array_put(tr);
4795 return 0;
4796 }
4797
tracing_single_release_tr(struct inode * inode,struct file * file)4798 static int tracing_single_release_tr(struct inode *inode, struct file *file)
4799 {
4800 struct trace_array *tr = inode->i_private;
4801
4802 trace_array_put(tr);
4803
4804 return single_release(inode, file);
4805 }
4806
tracing_open(struct inode * inode,struct file * file)4807 static int tracing_open(struct inode *inode, struct file *file)
4808 {
4809 struct trace_array *tr = inode->i_private;
4810 struct trace_iterator *iter;
4811 int ret;
4812
4813 ret = tracing_check_open_get_tr(tr);
4814 if (ret)
4815 return ret;
4816
4817 /* If this file was open for write, then erase contents */
4818 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
4819 int cpu = tracing_get_cpu(inode);
4820 struct array_buffer *trace_buf = &tr->array_buffer;
4821
4822 #ifdef CONFIG_TRACER_MAX_TRACE
4823 if (tr->current_trace->print_max)
4824 trace_buf = &tr->max_buffer;
4825 #endif
4826
4827 if (cpu == RING_BUFFER_ALL_CPUS)
4828 tracing_reset_online_cpus(trace_buf);
4829 else
4830 tracing_reset_cpu(trace_buf, cpu);
4831 }
4832
4833 if (file->f_mode & FMODE_READ) {
4834 iter = __tracing_open(inode, file, false);
4835 if (IS_ERR(iter))
4836 ret = PTR_ERR(iter);
4837 else if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
4838 iter->iter_flags |= TRACE_FILE_LAT_FMT;
4839 }
4840
4841 if (ret < 0)
4842 trace_array_put(tr);
4843
4844 return ret;
4845 }
4846
4847 /*
4848 * Some tracers are not suitable for instance buffers.
4849 * A tracer is always available for the global array (toplevel)
4850 * or if it explicitly states that it is.
4851 */
4852 static bool
trace_ok_for_array(struct tracer * t,struct trace_array * tr)4853 trace_ok_for_array(struct tracer *t, struct trace_array *tr)
4854 {
4855 #ifdef CONFIG_TRACER_SNAPSHOT
4856 /* arrays with mapped buffer range do not have snapshots */
4857 if (tr->range_addr_start && t->use_max_tr)
4858 return false;
4859 #endif
4860 return (tr->flags & TRACE_ARRAY_FL_GLOBAL) || t->allow_instances;
4861 }
4862
4863 /* Find the next tracer that this trace array may use */
4864 static struct tracer *
get_tracer_for_array(struct trace_array * tr,struct tracer * t)4865 get_tracer_for_array(struct trace_array *tr, struct tracer *t)
4866 {
4867 while (t && !trace_ok_for_array(t, tr))
4868 t = t->next;
4869
4870 return t;
4871 }
4872
4873 static void *
t_next(struct seq_file * m,void * v,loff_t * pos)4874 t_next(struct seq_file *m, void *v, loff_t *pos)
4875 {
4876 struct trace_array *tr = m->private;
4877 struct tracer *t = v;
4878
4879 (*pos)++;
4880
4881 if (t)
4882 t = get_tracer_for_array(tr, t->next);
4883
4884 return t;
4885 }
4886
t_start(struct seq_file * m,loff_t * pos)4887 static void *t_start(struct seq_file *m, loff_t *pos)
4888 {
4889 struct trace_array *tr = m->private;
4890 struct tracer *t;
4891 loff_t l = 0;
4892
4893 mutex_lock(&trace_types_lock);
4894
4895 t = get_tracer_for_array(tr, trace_types);
4896 for (; t && l < *pos; t = t_next(m, t, &l))
4897 ;
4898
4899 return t;
4900 }
4901
t_stop(struct seq_file * m,void * p)4902 static void t_stop(struct seq_file *m, void *p)
4903 {
4904 mutex_unlock(&trace_types_lock);
4905 }
4906
t_show(struct seq_file * m,void * v)4907 static int t_show(struct seq_file *m, void *v)
4908 {
4909 struct tracer *t = v;
4910
4911 if (!t)
4912 return 0;
4913
4914 seq_puts(m, t->name);
4915 if (t->next)
4916 seq_putc(m, ' ');
4917 else
4918 seq_putc(m, '\n');
4919
4920 return 0;
4921 }
4922
4923 static const struct seq_operations show_traces_seq_ops = {
4924 .start = t_start,
4925 .next = t_next,
4926 .stop = t_stop,
4927 .show = t_show,
4928 };
4929
show_traces_open(struct inode * inode,struct file * file)4930 static int show_traces_open(struct inode *inode, struct file *file)
4931 {
4932 struct trace_array *tr = inode->i_private;
4933 struct seq_file *m;
4934 int ret;
4935
4936 ret = tracing_check_open_get_tr(tr);
4937 if (ret)
4938 return ret;
4939
4940 ret = seq_open(file, &show_traces_seq_ops);
4941 if (ret) {
4942 trace_array_put(tr);
4943 return ret;
4944 }
4945
4946 m = file->private_data;
4947 m->private = tr;
4948
4949 return 0;
4950 }
4951
tracing_seq_release(struct inode * inode,struct file * file)4952 static int tracing_seq_release(struct inode *inode, struct file *file)
4953 {
4954 struct trace_array *tr = inode->i_private;
4955
4956 trace_array_put(tr);
4957 return seq_release(inode, file);
4958 }
4959
4960 static ssize_t
tracing_write_stub(struct file * filp,const char __user * ubuf,size_t count,loff_t * ppos)4961 tracing_write_stub(struct file *filp, const char __user *ubuf,
4962 size_t count, loff_t *ppos)
4963 {
4964 return count;
4965 }
4966
tracing_lseek(struct file * file,loff_t offset,int whence)4967 loff_t tracing_lseek(struct file *file, loff_t offset, int whence)
4968 {
4969 int ret;
4970
4971 if (file->f_mode & FMODE_READ)
4972 ret = seq_lseek(file, offset, whence);
4973 else
4974 file->f_pos = ret = 0;
4975
4976 return ret;
4977 }
4978
4979 static const struct file_operations tracing_fops = {
4980 .open = tracing_open,
4981 .read = seq_read,
4982 .read_iter = seq_read_iter,
4983 .splice_read = copy_splice_read,
4984 .write = tracing_write_stub,
4985 .llseek = tracing_lseek,
4986 .release = tracing_release,
4987 };
4988
4989 static const struct file_operations show_traces_fops = {
4990 .open = show_traces_open,
4991 .read = seq_read,
4992 .llseek = seq_lseek,
4993 .release = tracing_seq_release,
4994 };
4995
4996 static ssize_t
tracing_cpumask_read(struct file * filp,char __user * ubuf,size_t count,loff_t * ppos)4997 tracing_cpumask_read(struct file *filp, char __user *ubuf,
4998 size_t count, loff_t *ppos)
4999 {
5000 struct trace_array *tr = file_inode(filp)->i_private;
5001 char *mask_str;
5002 int len;
5003
5004 len = snprintf(NULL, 0, "%*pb\n",
5005 cpumask_pr_args(tr->tracing_cpumask)) + 1;
5006 mask_str = kmalloc(len, GFP_KERNEL);
5007 if (!mask_str)
5008 return -ENOMEM;
5009
5010 len = snprintf(mask_str, len, "%*pb\n",
5011 cpumask_pr_args(tr->tracing_cpumask));
5012 if (len >= count) {
5013 count = -EINVAL;
5014 goto out_err;
5015 }
5016 count = simple_read_from_buffer(ubuf, count, ppos, mask_str, len);
5017
5018 out_err:
5019 kfree(mask_str);
5020
5021 return count;
5022 }
5023
tracing_set_cpumask(struct trace_array * tr,cpumask_var_t tracing_cpumask_new)5024 int tracing_set_cpumask(struct trace_array *tr,
5025 cpumask_var_t tracing_cpumask_new)
5026 {
5027 int cpu;
5028
5029 if (!tr)
5030 return -EINVAL;
5031
5032 local_irq_disable();
5033 arch_spin_lock(&tr->max_lock);
5034 for_each_tracing_cpu(cpu) {
5035 /*
5036 * Increase/decrease the disabled counter if we are
5037 * about to flip a bit in the cpumask:
5038 */
5039 if (cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
5040 !cpumask_test_cpu(cpu, tracing_cpumask_new)) {
5041 atomic_inc(&per_cpu_ptr(tr->array_buffer.data, cpu)->disabled);
5042 ring_buffer_record_disable_cpu(tr->array_buffer.buffer, cpu);
5043 #ifdef CONFIG_TRACER_MAX_TRACE
5044 ring_buffer_record_disable_cpu(tr->max_buffer.buffer, cpu);
5045 #endif
5046 }
5047 if (!cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
5048 cpumask_test_cpu(cpu, tracing_cpumask_new)) {
5049 atomic_dec(&per_cpu_ptr(tr->array_buffer.data, cpu)->disabled);
5050 ring_buffer_record_enable_cpu(tr->array_buffer.buffer, cpu);
5051 #ifdef CONFIG_TRACER_MAX_TRACE
5052 ring_buffer_record_enable_cpu(tr->max_buffer.buffer, cpu);
5053 #endif
5054 }
5055 }
5056 arch_spin_unlock(&tr->max_lock);
5057 local_irq_enable();
5058
5059 cpumask_copy(tr->tracing_cpumask, tracing_cpumask_new);
5060
5061 return 0;
5062 }
5063
5064 static ssize_t
tracing_cpumask_write(struct file * filp,const char __user * ubuf,size_t count,loff_t * ppos)5065 tracing_cpumask_write(struct file *filp, const char __user *ubuf,
5066 size_t count, loff_t *ppos)
5067 {
5068 struct trace_array *tr = file_inode(filp)->i_private;
5069 cpumask_var_t tracing_cpumask_new;
5070 int err;
5071
5072 if (count == 0 || count > KMALLOC_MAX_SIZE)
5073 return -EINVAL;
5074
5075 if (!zalloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
5076 return -ENOMEM;
5077
5078 err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
5079 if (err)
5080 goto err_free;
5081
5082 err = tracing_set_cpumask(tr, tracing_cpumask_new);
5083 if (err)
5084 goto err_free;
5085
5086 free_cpumask_var(tracing_cpumask_new);
5087
5088 return count;
5089
5090 err_free:
5091 free_cpumask_var(tracing_cpumask_new);
5092
5093 return err;
5094 }
5095
5096 static const struct file_operations tracing_cpumask_fops = {
5097 .open = tracing_open_generic_tr,
5098 .read = tracing_cpumask_read,
5099 .write = tracing_cpumask_write,
5100 .release = tracing_release_generic_tr,
5101 .llseek = generic_file_llseek,
5102 };
5103
tracing_trace_options_show(struct seq_file * m,void * v)5104 static int tracing_trace_options_show(struct seq_file *m, void *v)
5105 {
5106 struct tracer_opt *trace_opts;
5107 struct trace_array *tr = m->private;
5108 u32 tracer_flags;
5109 int i;
5110
5111 guard(mutex)(&trace_types_lock);
5112
5113 tracer_flags = tr->current_trace->flags->val;
5114 trace_opts = tr->current_trace->flags->opts;
5115
5116 for (i = 0; trace_options[i]; i++) {
5117 if (tr->trace_flags & (1 << i))
5118 seq_printf(m, "%s\n", trace_options[i]);
5119 else
5120 seq_printf(m, "no%s\n", trace_options[i]);
5121 }
5122
5123 for (i = 0; trace_opts[i].name; i++) {
5124 if (tracer_flags & trace_opts[i].bit)
5125 seq_printf(m, "%s\n", trace_opts[i].name);
5126 else
5127 seq_printf(m, "no%s\n", trace_opts[i].name);
5128 }
5129
5130 return 0;
5131 }
5132
__set_tracer_option(struct trace_array * tr,struct tracer_flags * tracer_flags,struct tracer_opt * opts,int neg)5133 static int __set_tracer_option(struct trace_array *tr,
5134 struct tracer_flags *tracer_flags,
5135 struct tracer_opt *opts, int neg)
5136 {
5137 struct tracer *trace = tracer_flags->trace;
5138 int ret;
5139
5140 ret = trace->set_flag(tr, tracer_flags->val, opts->bit, !neg);
5141 if (ret)
5142 return ret;
5143
5144 if (neg)
5145 tracer_flags->val &= ~opts->bit;
5146 else
5147 tracer_flags->val |= opts->bit;
5148 return 0;
5149 }
5150
5151 /* Try to assign a tracer specific option */
set_tracer_option(struct trace_array * tr,char * cmp,int neg)5152 static int set_tracer_option(struct trace_array *tr, char *cmp, int neg)
5153 {
5154 struct tracer *trace = tr->current_trace;
5155 struct tracer_flags *tracer_flags = trace->flags;
5156 struct tracer_opt *opts = NULL;
5157 int i;
5158
5159 for (i = 0; tracer_flags->opts[i].name; i++) {
5160 opts = &tracer_flags->opts[i];
5161
5162 if (strcmp(cmp, opts->name) == 0)
5163 return __set_tracer_option(tr, trace->flags, opts, neg);
5164 }
5165
5166 return -EINVAL;
5167 }
5168
5169 /* Some tracers require overwrite to stay enabled */
trace_keep_overwrite(struct tracer * tracer,u32 mask,int set)5170 int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set)
5171 {
5172 if (tracer->enabled && (mask & TRACE_ITER_OVERWRITE) && !set)
5173 return -1;
5174
5175 return 0;
5176 }
5177
set_tracer_flag(struct trace_array * tr,unsigned int mask,int enabled)5178 int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled)
5179 {
5180 if ((mask == TRACE_ITER_RECORD_TGID) ||
5181 (mask == TRACE_ITER_RECORD_CMD) ||
5182 (mask == TRACE_ITER_TRACE_PRINTK))
5183 lockdep_assert_held(&event_mutex);
5184
5185 /* do nothing if flag is already set */
5186 if (!!(tr->trace_flags & mask) == !!enabled)
5187 return 0;
5188
5189 /* Give the tracer a chance to approve the change */
5190 if (tr->current_trace->flag_changed)
5191 if (tr->current_trace->flag_changed(tr, mask, !!enabled))
5192 return -EINVAL;
5193
5194 if (mask == TRACE_ITER_TRACE_PRINTK) {
5195 if (enabled) {
5196 update_printk_trace(tr);
5197 } else {
5198 /*
5199 * The global_trace cannot clear this.
5200 * It's flag only gets cleared if another instance sets it.
5201 */
5202 if (printk_trace == &global_trace)
5203 return -EINVAL;
5204 /*
5205 * An instance must always have it set.
5206 * by default, that's the global_trace instane.
5207 */
5208 if (printk_trace == tr)
5209 update_printk_trace(&global_trace);
5210 }
5211 }
5212
5213 if (enabled)
5214 tr->trace_flags |= mask;
5215 else
5216 tr->trace_flags &= ~mask;
5217
5218 if (mask == TRACE_ITER_RECORD_CMD)
5219 trace_event_enable_cmd_record(enabled);
5220
5221 if (mask == TRACE_ITER_RECORD_TGID) {
5222
5223 if (trace_alloc_tgid_map() < 0) {
5224 tr->trace_flags &= ~TRACE_ITER_RECORD_TGID;
5225 return -ENOMEM;
5226 }
5227
5228 trace_event_enable_tgid_record(enabled);
5229 }
5230
5231 if (mask == TRACE_ITER_EVENT_FORK)
5232 trace_event_follow_fork(tr, enabled);
5233
5234 if (mask == TRACE_ITER_FUNC_FORK)
5235 ftrace_pid_follow_fork(tr, enabled);
5236
5237 if (mask == TRACE_ITER_OVERWRITE) {
5238 ring_buffer_change_overwrite(tr->array_buffer.buffer, enabled);
5239 #ifdef CONFIG_TRACER_MAX_TRACE
5240 ring_buffer_change_overwrite(tr->max_buffer.buffer, enabled);
5241 #endif
5242 }
5243
5244 if (mask == TRACE_ITER_PRINTK) {
5245 trace_printk_start_stop_comm(enabled);
5246 trace_printk_control(enabled);
5247 }
5248
5249 return 0;
5250 }
5251
trace_set_options(struct trace_array * tr,char * option)5252 int trace_set_options(struct trace_array *tr, char *option)
5253 {
5254 char *cmp;
5255 int neg = 0;
5256 int ret;
5257 size_t orig_len = strlen(option);
5258 int len;
5259
5260 cmp = strstrip(option);
5261
5262 len = str_has_prefix(cmp, "no");
5263 if (len)
5264 neg = 1;
5265
5266 cmp += len;
5267
5268 mutex_lock(&event_mutex);
5269 mutex_lock(&trace_types_lock);
5270
5271 ret = match_string(trace_options, -1, cmp);
5272 /* If no option could be set, test the specific tracer options */
5273 if (ret < 0)
5274 ret = set_tracer_option(tr, cmp, neg);
5275 else
5276 ret = set_tracer_flag(tr, 1 << ret, !neg);
5277
5278 mutex_unlock(&trace_types_lock);
5279 mutex_unlock(&event_mutex);
5280
5281 /*
5282 * If the first trailing whitespace is replaced with '\0' by strstrip,
5283 * turn it back into a space.
5284 */
5285 if (orig_len > strlen(option))
5286 option[strlen(option)] = ' ';
5287
5288 return ret;
5289 }
5290
apply_trace_boot_options(void)5291 static void __init apply_trace_boot_options(void)
5292 {
5293 char *buf = trace_boot_options_buf;
5294 char *option;
5295
5296 while (true) {
5297 option = strsep(&buf, ",");
5298
5299 if (!option)
5300 break;
5301
5302 if (*option)
5303 trace_set_options(&global_trace, option);
5304
5305 /* Put back the comma to allow this to be called again */
5306 if (buf)
5307 *(buf - 1) = ',';
5308 }
5309 }
5310
5311 static ssize_t
tracing_trace_options_write(struct file * filp,const char __user * ubuf,size_t cnt,loff_t * ppos)5312 tracing_trace_options_write(struct file *filp, const char __user *ubuf,
5313 size_t cnt, loff_t *ppos)
5314 {
5315 struct seq_file *m = filp->private_data;
5316 struct trace_array *tr = m->private;
5317 char buf[64];
5318 int ret;
5319
5320 if (cnt >= sizeof(buf))
5321 return -EINVAL;
5322
5323 if (copy_from_user(buf, ubuf, cnt))
5324 return -EFAULT;
5325
5326 buf[cnt] = 0;
5327
5328 ret = trace_set_options(tr, buf);
5329 if (ret < 0)
5330 return ret;
5331
5332 *ppos += cnt;
5333
5334 return cnt;
5335 }
5336
tracing_trace_options_open(struct inode * inode,struct file * file)5337 static int tracing_trace_options_open(struct inode *inode, struct file *file)
5338 {
5339 struct trace_array *tr = inode->i_private;
5340 int ret;
5341
5342 ret = tracing_check_open_get_tr(tr);
5343 if (ret)
5344 return ret;
5345
5346 ret = single_open(file, tracing_trace_options_show, inode->i_private);
5347 if (ret < 0)
5348 trace_array_put(tr);
5349
5350 return ret;
5351 }
5352
5353 static const struct file_operations tracing_iter_fops = {
5354 .open = tracing_trace_options_open,
5355 .read = seq_read,
5356 .llseek = seq_lseek,
5357 .release = tracing_single_release_tr,
5358 .write = tracing_trace_options_write,
5359 };
5360
5361 static const char readme_msg[] =
5362 "tracing mini-HOWTO:\n\n"
5363 "By default tracefs removes all OTH file permission bits.\n"
5364 "When mounting tracefs an optional group id can be specified\n"
5365 "which adds the group to every directory and file in tracefs:\n\n"
5366 "\t e.g. mount -t tracefs [-o [gid=<gid>]] nodev /sys/kernel/tracing\n\n"
5367 "# echo 0 > tracing_on : quick way to disable tracing\n"
5368 "# echo 1 > tracing_on : quick way to re-enable tracing\n\n"
5369 " Important files:\n"
5370 " trace\t\t\t- The static contents of the buffer\n"
5371 "\t\t\t To clear the buffer write into this file: echo > trace\n"
5372 " trace_pipe\t\t- A consuming read to see the contents of the buffer\n"
5373 " current_tracer\t- function and latency tracers\n"
5374 " available_tracers\t- list of configured tracers for current_tracer\n"
5375 " error_log\t- error log for failed commands (that support it)\n"
5376 " buffer_size_kb\t- view and modify size of per cpu buffer\n"
5377 " buffer_total_size_kb - view total size of all cpu buffers\n\n"
5378 " trace_clock\t\t- change the clock used to order events\n"
5379 " local: Per cpu clock but may not be synced across CPUs\n"
5380 " global: Synced across CPUs but slows tracing down.\n"
5381 " counter: Not a clock, but just an increment\n"
5382 " uptime: Jiffy counter from time of boot\n"
5383 " perf: Same clock that perf events use\n"
5384 #ifdef CONFIG_X86_64
5385 " x86-tsc: TSC cycle counter\n"
5386 #endif
5387 "\n timestamp_mode\t- view the mode used to timestamp events\n"
5388 " delta: Delta difference against a buffer-wide timestamp\n"
5389 " absolute: Absolute (standalone) timestamp\n"
5390 "\n trace_marker\t\t- Writes into this file writes into the kernel buffer\n"
5391 "\n trace_marker_raw\t\t- Writes into this file writes binary data into the kernel buffer\n"
5392 " tracing_cpumask\t- Limit which CPUs to trace\n"
5393 " instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
5394 "\t\t\t Remove sub-buffer with rmdir\n"
5395 " trace_options\t\t- Set format or modify how tracing happens\n"
5396 "\t\t\t Disable an option by prefixing 'no' to the\n"
5397 "\t\t\t option name\n"
5398 " saved_cmdlines_size\t- echo command number in here to store comm-pid list\n"
5399 #ifdef CONFIG_DYNAMIC_FTRACE
5400 "\n available_filter_functions - list of functions that can be filtered on\n"
5401 " set_ftrace_filter\t- echo function name in here to only trace these\n"
5402 "\t\t\t functions\n"
5403 "\t accepts: func_full_name or glob-matching-pattern\n"
5404 "\t modules: Can select a group via module\n"
5405 "\t Format: :mod:<module-name>\n"
5406 "\t example: echo :mod:ext3 > set_ftrace_filter\n"
5407 "\t triggers: a command to perform when function is hit\n"
5408 "\t Format: <function>:<trigger>[:count]\n"
5409 "\t trigger: traceon, traceoff\n"
5410 "\t\t enable_event:<system>:<event>\n"
5411 "\t\t disable_event:<system>:<event>\n"
5412 #ifdef CONFIG_STACKTRACE
5413 "\t\t stacktrace\n"
5414 #endif
5415 #ifdef CONFIG_TRACER_SNAPSHOT
5416 "\t\t snapshot\n"
5417 #endif
5418 "\t\t dump\n"
5419 "\t\t cpudump\n"
5420 "\t example: echo do_fault:traceoff > set_ftrace_filter\n"
5421 "\t echo do_trap:traceoff:3 > set_ftrace_filter\n"
5422 "\t The first one will disable tracing every time do_fault is hit\n"
5423 "\t The second will disable tracing at most 3 times when do_trap is hit\n"
5424 "\t The first time do trap is hit and it disables tracing, the\n"
5425 "\t counter will decrement to 2. If tracing is already disabled,\n"
5426 "\t the counter will not decrement. It only decrements when the\n"
5427 "\t trigger did work\n"
5428 "\t To remove trigger without count:\n"
5429 "\t echo '!<function>:<trigger> > set_ftrace_filter\n"
5430 "\t To remove trigger with a count:\n"
5431 "\t echo '!<function>:<trigger>:0 > set_ftrace_filter\n"
5432 " set_ftrace_notrace\t- echo function name in here to never trace.\n"
5433 "\t accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
5434 "\t modules: Can select a group via module command :mod:\n"
5435 "\t Does not accept triggers\n"
5436 #endif /* CONFIG_DYNAMIC_FTRACE */
5437 #ifdef CONFIG_FUNCTION_TRACER
5438 " set_ftrace_pid\t- Write pid(s) to only function trace those pids\n"
5439 "\t\t (function)\n"
5440 " set_ftrace_notrace_pid\t- Write pid(s) to not function trace those pids\n"
5441 "\t\t (function)\n"
5442 #endif
5443 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
5444 " set_graph_function\t- Trace the nested calls of a function (function_graph)\n"
5445 " set_graph_notrace\t- Do not trace the nested calls of a function (function_graph)\n"
5446 " max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n"
5447 #endif
5448 #ifdef CONFIG_TRACER_SNAPSHOT
5449 "\n snapshot\t\t- Like 'trace' but shows the content of the static\n"
5450 "\t\t\t snapshot buffer. Read the contents for more\n"
5451 "\t\t\t information\n"
5452 #endif
5453 #ifdef CONFIG_STACK_TRACER
5454 " stack_trace\t\t- Shows the max stack trace when active\n"
5455 " stack_max_size\t- Shows current max stack size that was traced\n"
5456 "\t\t\t Write into this file to reset the max size (trigger a\n"
5457 "\t\t\t new trace)\n"
5458 #ifdef CONFIG_DYNAMIC_FTRACE
5459 " stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace\n"
5460 "\t\t\t traces\n"
5461 #endif
5462 #endif /* CONFIG_STACK_TRACER */
5463 #ifdef CONFIG_DYNAMIC_EVENTS
5464 " dynamic_events\t\t- Create/append/remove/show the generic dynamic events\n"
5465 "\t\t\t Write into this file to define/undefine new trace events.\n"
5466 #endif
5467 #ifdef CONFIG_KPROBE_EVENTS
5468 " kprobe_events\t\t- Create/append/remove/show the kernel dynamic events\n"
5469 "\t\t\t Write into this file to define/undefine new trace events.\n"
5470 #endif
5471 #ifdef CONFIG_UPROBE_EVENTS
5472 " uprobe_events\t\t- Create/append/remove/show the userspace dynamic events\n"
5473 "\t\t\t Write into this file to define/undefine new trace events.\n"
5474 #endif
5475 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS) || \
5476 defined(CONFIG_FPROBE_EVENTS)
5477 "\t accepts: event-definitions (one definition per line)\n"
5478 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
5479 "\t Format: p[:[<group>/][<event>]] <place> [<args>]\n"
5480 "\t r[maxactive][:[<group>/][<event>]] <place> [<args>]\n"
5481 #endif
5482 #ifdef CONFIG_FPROBE_EVENTS
5483 "\t f[:[<group>/][<event>]] <func-name>[%return] [<args>]\n"
5484 "\t t[:[<group>/][<event>]] <tracepoint> [<args>]\n"
5485 #endif
5486 #ifdef CONFIG_HIST_TRIGGERS
5487 "\t s:[synthetic/]<event> <field> [<field>]\n"
5488 #endif
5489 "\t e[:[<group>/][<event>]] <attached-group>.<attached-event> [<args>] [if <filter>]\n"
5490 "\t -:[<group>/][<event>]\n"
5491 #ifdef CONFIG_KPROBE_EVENTS
5492 "\t place: [<module>:]<symbol>[+<offset>]|<memaddr>\n"
5493 "place (kretprobe): [<module>:]<symbol>[+<offset>]%return|<memaddr>\n"
5494 #endif
5495 #ifdef CONFIG_UPROBE_EVENTS
5496 " place (uprobe): <path>:<offset>[%return][(ref_ctr_offset)]\n"
5497 #endif
5498 "\t args: <name>=fetcharg[:type]\n"
5499 "\t fetcharg: (%<register>|$<efield>), @<address>, @<symbol>[+|-<offset>],\n"
5500 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
5501 "\t $stack<index>, $stack, $retval, $comm, $arg<N>,\n"
5502 #ifdef CONFIG_PROBE_EVENTS_BTF_ARGS
5503 "\t <argname>[->field[->field|.field...]],\n"
5504 #endif
5505 #else
5506 "\t $stack<index>, $stack, $retval, $comm,\n"
5507 #endif
5508 "\t +|-[u]<offset>(<fetcharg>), \\imm-value, \\\"imm-string\"\n"
5509 "\t kernel return probes support: $retval, $arg<N>, $comm\n"
5510 "\t type: s8/16/32/64, u8/16/32/64, x8/16/32/64, char, string, symbol,\n"
5511 "\t b<bit-width>@<bit-offset>/<container-size>, ustring,\n"
5512 "\t symstr, %pd/%pD, <type>\\[<array-size>\\]\n"
5513 #ifdef CONFIG_HIST_TRIGGERS
5514 "\t field: <stype> <name>;\n"
5515 "\t stype: u8/u16/u32/u64, s8/s16/s32/s64, pid_t,\n"
5516 "\t [unsigned] char/int/long\n"
5517 #endif
5518 "\t efield: For event probes ('e' types), the field is on of the fields\n"
5519 "\t of the <attached-group>/<attached-event>.\n"
5520 #endif
5521 " set_event\t\t- Enables events by name written into it\n"
5522 "\t\t\t Can enable module events via: :mod:<module>\n"
5523 " events/\t\t- Directory containing all trace event subsystems:\n"
5524 " enable\t\t- Write 0/1 to enable/disable tracing of all events\n"
5525 " events/<system>/\t- Directory containing all trace events for <system>:\n"
5526 " enable\t\t- Write 0/1 to enable/disable tracing of all <system>\n"
5527 "\t\t\t events\n"
5528 " filter\t\t- If set, only events passing filter are traced\n"
5529 " events/<system>/<event>/\t- Directory containing control files for\n"
5530 "\t\t\t <event>:\n"
5531 " enable\t\t- Write 0/1 to enable/disable tracing of <event>\n"
5532 " filter\t\t- If set, only events passing filter are traced\n"
5533 " trigger\t\t- If set, a command to perform when event is hit\n"
5534 "\t Format: <trigger>[:count][if <filter>]\n"
5535 "\t trigger: traceon, traceoff\n"
5536 "\t enable_event:<system>:<event>\n"
5537 "\t disable_event:<system>:<event>\n"
5538 #ifdef CONFIG_HIST_TRIGGERS
5539 "\t enable_hist:<system>:<event>\n"
5540 "\t disable_hist:<system>:<event>\n"
5541 #endif
5542 #ifdef CONFIG_STACKTRACE
5543 "\t\t stacktrace\n"
5544 #endif
5545 #ifdef CONFIG_TRACER_SNAPSHOT
5546 "\t\t snapshot\n"
5547 #endif
5548 #ifdef CONFIG_HIST_TRIGGERS
5549 "\t\t hist (see below)\n"
5550 #endif
5551 "\t example: echo traceoff > events/block/block_unplug/trigger\n"
5552 "\t echo traceoff:3 > events/block/block_unplug/trigger\n"
5553 "\t echo 'enable_event:kmem:kmalloc:3 if nr_rq > 1' > \\\n"
5554 "\t events/block/block_unplug/trigger\n"
5555 "\t The first disables tracing every time block_unplug is hit.\n"
5556 "\t The second disables tracing the first 3 times block_unplug is hit.\n"
5557 "\t The third enables the kmalloc event the first 3 times block_unplug\n"
5558 "\t is hit and has value of greater than 1 for the 'nr_rq' event field.\n"
5559 "\t Like function triggers, the counter is only decremented if it\n"
5560 "\t enabled or disabled tracing.\n"
5561 "\t To remove a trigger without a count:\n"
5562 "\t echo '!<trigger> > <system>/<event>/trigger\n"
5563 "\t To remove a trigger with a count:\n"
5564 "\t echo '!<trigger>:0 > <system>/<event>/trigger\n"
5565 "\t Filters can be ignored when removing a trigger.\n"
5566 #ifdef CONFIG_HIST_TRIGGERS
5567 " hist trigger\t- If set, event hits are aggregated into a hash table\n"
5568 "\t Format: hist:keys=<field1[,field2,...]>\n"
5569 "\t [:<var1>=<field|var_ref|numeric_literal>[,<var2>=...]]\n"
5570 "\t [:values=<field1[,field2,...]>]\n"
5571 "\t [:sort=<field1[,field2,...]>]\n"
5572 "\t [:size=#entries]\n"
5573 "\t [:pause][:continue][:clear]\n"
5574 "\t [:name=histname1]\n"
5575 "\t [:nohitcount]\n"
5576 "\t [:<handler>.<action>]\n"
5577 "\t [if <filter>]\n\n"
5578 "\t Note, special fields can be used as well:\n"
5579 "\t common_timestamp - to record current timestamp\n"
5580 "\t common_cpu - to record the CPU the event happened on\n"
5581 "\n"
5582 "\t A hist trigger variable can be:\n"
5583 "\t - a reference to a field e.g. x=current_timestamp,\n"
5584 "\t - a reference to another variable e.g. y=$x,\n"
5585 "\t - a numeric literal: e.g. ms_per_sec=1000,\n"
5586 "\t - an arithmetic expression: e.g. time_secs=current_timestamp/1000\n"
5587 "\n"
5588 "\t hist trigger arithmetic expressions support addition(+), subtraction(-),\n"
5589 "\t multiplication(*) and division(/) operators. An operand can be either a\n"
5590 "\t variable reference, field or numeric literal.\n"
5591 "\n"
5592 "\t When a matching event is hit, an entry is added to a hash\n"
5593 "\t table using the key(s) and value(s) named, and the value of a\n"
5594 "\t sum called 'hitcount' is incremented. Keys and values\n"
5595 "\t correspond to fields in the event's format description. Keys\n"
5596 "\t can be any field, or the special string 'common_stacktrace'.\n"
5597 "\t Compound keys consisting of up to two fields can be specified\n"
5598 "\t by the 'keys' keyword. Values must correspond to numeric\n"
5599 "\t fields. Sort keys consisting of up to two fields can be\n"
5600 "\t specified using the 'sort' keyword. The sort direction can\n"
5601 "\t be modified by appending '.descending' or '.ascending' to a\n"
5602 "\t sort field. The 'size' parameter can be used to specify more\n"
5603 "\t or fewer than the default 2048 entries for the hashtable size.\n"
5604 "\t If a hist trigger is given a name using the 'name' parameter,\n"
5605 "\t its histogram data will be shared with other triggers of the\n"
5606 "\t same name, and trigger hits will update this common data.\n\n"
5607 "\t Reading the 'hist' file for the event will dump the hash\n"
5608 "\t table in its entirety to stdout. If there are multiple hist\n"
5609 "\t triggers attached to an event, there will be a table for each\n"
5610 "\t trigger in the output. The table displayed for a named\n"
5611 "\t trigger will be the same as any other instance having the\n"
5612 "\t same name. The default format used to display a given field\n"
5613 "\t can be modified by appending any of the following modifiers\n"
5614 "\t to the field name, as applicable:\n\n"
5615 "\t .hex display a number as a hex value\n"
5616 "\t .sym display an address as a symbol\n"
5617 "\t .sym-offset display an address as a symbol and offset\n"
5618 "\t .execname display a common_pid as a program name\n"
5619 "\t .syscall display a syscall id as a syscall name\n"
5620 "\t .log2 display log2 value rather than raw number\n"
5621 "\t .buckets=size display values in groups of size rather than raw number\n"
5622 "\t .usecs display a common_timestamp in microseconds\n"
5623 "\t .percent display a number of percentage value\n"
5624 "\t .graph display a bar-graph of a value\n\n"
5625 "\t The 'pause' parameter can be used to pause an existing hist\n"
5626 "\t trigger or to start a hist trigger but not log any events\n"
5627 "\t until told to do so. 'continue' can be used to start or\n"
5628 "\t restart a paused hist trigger.\n\n"
5629 "\t The 'clear' parameter will clear the contents of a running\n"
5630 "\t hist trigger and leave its current paused/active state\n"
5631 "\t unchanged.\n\n"
5632 "\t The 'nohitcount' (or NOHC) parameter will suppress display of\n"
5633 "\t raw hitcount in the histogram.\n\n"
5634 "\t The enable_hist and disable_hist triggers can be used to\n"
5635 "\t have one event conditionally start and stop another event's\n"
5636 "\t already-attached hist trigger. The syntax is analogous to\n"
5637 "\t the enable_event and disable_event triggers.\n\n"
5638 "\t Hist trigger handlers and actions are executed whenever a\n"
5639 "\t a histogram entry is added or updated. They take the form:\n\n"
5640 "\t <handler>.<action>\n\n"
5641 "\t The available handlers are:\n\n"
5642 "\t onmatch(matching.event) - invoke on addition or update\n"
5643 "\t onmax(var) - invoke if var exceeds current max\n"
5644 "\t onchange(var) - invoke action if var changes\n\n"
5645 "\t The available actions are:\n\n"
5646 "\t trace(<synthetic_event>,param list) - generate synthetic event\n"
5647 "\t save(field,...) - save current event fields\n"
5648 #ifdef CONFIG_TRACER_SNAPSHOT
5649 "\t snapshot() - snapshot the trace buffer\n\n"
5650 #endif
5651 #ifdef CONFIG_SYNTH_EVENTS
5652 " events/synthetic_events\t- Create/append/remove/show synthetic events\n"
5653 "\t Write into this file to define/undefine new synthetic events.\n"
5654 "\t example: echo 'myevent u64 lat; char name[]; long[] stack' >> synthetic_events\n"
5655 #endif
5656 #endif
5657 ;
5658
5659 static ssize_t
tracing_readme_read(struct file * filp,char __user * ubuf,size_t cnt,loff_t * ppos)5660 tracing_readme_read(struct file *filp, char __user *ubuf,
5661 size_t cnt, loff_t *ppos)
5662 {
5663 return simple_read_from_buffer(ubuf, cnt, ppos,
5664 readme_msg, strlen(readme_msg));
5665 }
5666
5667 static const struct file_operations tracing_readme_fops = {
5668 .open = tracing_open_generic,
5669 .read = tracing_readme_read,
5670 .llseek = generic_file_llseek,
5671 };
5672
5673 #ifdef CONFIG_TRACE_EVAL_MAP_FILE
5674 static union trace_eval_map_item *
update_eval_map(union trace_eval_map_item * ptr)5675 update_eval_map(union trace_eval_map_item *ptr)
5676 {
5677 if (!ptr->map.eval_string) {
5678 if (ptr->tail.next) {
5679 ptr = ptr->tail.next;
5680 /* Set ptr to the next real item (skip head) */
5681 ptr++;
5682 } else
5683 return NULL;
5684 }
5685 return ptr;
5686 }
5687
eval_map_next(struct seq_file * m,void * v,loff_t * pos)5688 static void *eval_map_next(struct seq_file *m, void *v, loff_t *pos)
5689 {
5690 union trace_eval_map_item *ptr = v;
5691
5692 /*
5693 * Paranoid! If ptr points to end, we don't want to increment past it.
5694 * This really should never happen.
5695 */
5696 (*pos)++;
5697 ptr = update_eval_map(ptr);
5698 if (WARN_ON_ONCE(!ptr))
5699 return NULL;
5700
5701 ptr++;
5702 ptr = update_eval_map(ptr);
5703
5704 return ptr;
5705 }
5706
eval_map_start(struct seq_file * m,loff_t * pos)5707 static void *eval_map_start(struct seq_file *m, loff_t *pos)
5708 {
5709 union trace_eval_map_item *v;
5710 loff_t l = 0;
5711
5712 mutex_lock(&trace_eval_mutex);
5713
5714 v = trace_eval_maps;
5715 if (v)
5716 v++;
5717
5718 while (v && l < *pos) {
5719 v = eval_map_next(m, v, &l);
5720 }
5721
5722 return v;
5723 }
5724
eval_map_stop(struct seq_file * m,void * v)5725 static void eval_map_stop(struct seq_file *m, void *v)
5726 {
5727 mutex_unlock(&trace_eval_mutex);
5728 }
5729
eval_map_show(struct seq_file * m,void * v)5730 static int eval_map_show(struct seq_file *m, void *v)
5731 {
5732 union trace_eval_map_item *ptr = v;
5733
5734 seq_printf(m, "%s %ld (%s)\n",
5735 ptr->map.eval_string, ptr->map.eval_value,
5736 ptr->map.system);
5737
5738 return 0;
5739 }
5740
5741 static const struct seq_operations tracing_eval_map_seq_ops = {
5742 .start = eval_map_start,
5743 .next = eval_map_next,
5744 .stop = eval_map_stop,
5745 .show = eval_map_show,
5746 };
5747
tracing_eval_map_open(struct inode * inode,struct file * filp)5748 static int tracing_eval_map_open(struct inode *inode, struct file *filp)
5749 {
5750 int ret;
5751
5752 ret = tracing_check_open_get_tr(NULL);
5753 if (ret)
5754 return ret;
5755
5756 return seq_open(filp, &tracing_eval_map_seq_ops);
5757 }
5758
5759 static const struct file_operations tracing_eval_map_fops = {
5760 .open = tracing_eval_map_open,
5761 .read = seq_read,
5762 .llseek = seq_lseek,
5763 .release = seq_release,
5764 };
5765
5766 static inline union trace_eval_map_item *
trace_eval_jmp_to_tail(union trace_eval_map_item * ptr)5767 trace_eval_jmp_to_tail(union trace_eval_map_item *ptr)
5768 {
5769 /* Return tail of array given the head */
5770 return ptr + ptr->head.length + 1;
5771 }
5772
5773 static void
trace_insert_eval_map_file(struct module * mod,struct trace_eval_map ** start,int len)5774 trace_insert_eval_map_file(struct module *mod, struct trace_eval_map **start,
5775 int len)
5776 {
5777 struct trace_eval_map **stop;
5778 struct trace_eval_map **map;
5779 union trace_eval_map_item *map_array;
5780 union trace_eval_map_item *ptr;
5781
5782 stop = start + len;
5783
5784 /*
5785 * The trace_eval_maps contains the map plus a head and tail item,
5786 * where the head holds the module and length of array, and the
5787 * tail holds a pointer to the next list.
5788 */
5789 map_array = kmalloc_array(len + 2, sizeof(*map_array), GFP_KERNEL);
5790 if (!map_array) {
5791 pr_warn("Unable to allocate trace eval mapping\n");
5792 return;
5793 }
5794
5795 guard(mutex)(&trace_eval_mutex);
5796
5797 if (!trace_eval_maps)
5798 trace_eval_maps = map_array;
5799 else {
5800 ptr = trace_eval_maps;
5801 for (;;) {
5802 ptr = trace_eval_jmp_to_tail(ptr);
5803 if (!ptr->tail.next)
5804 break;
5805 ptr = ptr->tail.next;
5806
5807 }
5808 ptr->tail.next = map_array;
5809 }
5810 map_array->head.mod = mod;
5811 map_array->head.length = len;
5812 map_array++;
5813
5814 for (map = start; (unsigned long)map < (unsigned long)stop; map++) {
5815 map_array->map = **map;
5816 map_array++;
5817 }
5818 memset(map_array, 0, sizeof(*map_array));
5819 }
5820
trace_create_eval_file(struct dentry * d_tracer)5821 static void trace_create_eval_file(struct dentry *d_tracer)
5822 {
5823 trace_create_file("eval_map", TRACE_MODE_READ, d_tracer,
5824 NULL, &tracing_eval_map_fops);
5825 }
5826
5827 #else /* CONFIG_TRACE_EVAL_MAP_FILE */
trace_create_eval_file(struct dentry * d_tracer)5828 static inline void trace_create_eval_file(struct dentry *d_tracer) { }
trace_insert_eval_map_file(struct module * mod,struct trace_eval_map ** start,int len)5829 static inline void trace_insert_eval_map_file(struct module *mod,
5830 struct trace_eval_map **start, int len) { }
5831 #endif /* !CONFIG_TRACE_EVAL_MAP_FILE */
5832
trace_insert_eval_map(struct module * mod,struct trace_eval_map ** start,int len)5833 static void trace_insert_eval_map(struct module *mod,
5834 struct trace_eval_map **start, int len)
5835 {
5836 struct trace_eval_map **map;
5837
5838 if (len <= 0)
5839 return;
5840
5841 map = start;
5842
5843 trace_event_eval_update(map, len);
5844
5845 trace_insert_eval_map_file(mod, start, len);
5846 }
5847
5848 static ssize_t
tracing_set_trace_read(struct file * filp,char __user * ubuf,size_t cnt,loff_t * ppos)5849 tracing_set_trace_read(struct file *filp, char __user *ubuf,
5850 size_t cnt, loff_t *ppos)
5851 {
5852 struct trace_array *tr = filp->private_data;
5853 char buf[MAX_TRACER_SIZE+2];
5854 int r;
5855
5856 mutex_lock(&trace_types_lock);
5857 r = sprintf(buf, "%s\n", tr->current_trace->name);
5858 mutex_unlock(&trace_types_lock);
5859
5860 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
5861 }
5862
tracer_init(struct tracer * t,struct trace_array * tr)5863 int tracer_init(struct tracer *t, struct trace_array *tr)
5864 {
5865 tracing_reset_online_cpus(&tr->array_buffer);
5866 return t->init(tr);
5867 }
5868
set_buffer_entries(struct array_buffer * buf,unsigned long val)5869 static void set_buffer_entries(struct array_buffer *buf, unsigned long val)
5870 {
5871 int cpu;
5872
5873 for_each_tracing_cpu(cpu)
5874 per_cpu_ptr(buf->data, cpu)->entries = val;
5875 }
5876
update_buffer_entries(struct array_buffer * buf,int cpu)5877 static void update_buffer_entries(struct array_buffer *buf, int cpu)
5878 {
5879 if (cpu == RING_BUFFER_ALL_CPUS) {
5880 set_buffer_entries(buf, ring_buffer_size(buf->buffer, 0));
5881 } else {
5882 per_cpu_ptr(buf->data, cpu)->entries = ring_buffer_size(buf->buffer, cpu);
5883 }
5884 }
5885
5886 #ifdef CONFIG_TRACER_MAX_TRACE
5887 /* resize @tr's buffer to the size of @size_tr's entries */
resize_buffer_duplicate_size(struct array_buffer * trace_buf,struct array_buffer * size_buf,int cpu_id)5888 static int resize_buffer_duplicate_size(struct array_buffer *trace_buf,
5889 struct array_buffer *size_buf, int cpu_id)
5890 {
5891 int cpu, ret = 0;
5892
5893 if (cpu_id == RING_BUFFER_ALL_CPUS) {
5894 for_each_tracing_cpu(cpu) {
5895 ret = ring_buffer_resize(trace_buf->buffer,
5896 per_cpu_ptr(size_buf->data, cpu)->entries, cpu);
5897 if (ret < 0)
5898 break;
5899 per_cpu_ptr(trace_buf->data, cpu)->entries =
5900 per_cpu_ptr(size_buf->data, cpu)->entries;
5901 }
5902 } else {
5903 ret = ring_buffer_resize(trace_buf->buffer,
5904 per_cpu_ptr(size_buf->data, cpu_id)->entries, cpu_id);
5905 if (ret == 0)
5906 per_cpu_ptr(trace_buf->data, cpu_id)->entries =
5907 per_cpu_ptr(size_buf->data, cpu_id)->entries;
5908 }
5909
5910 return ret;
5911 }
5912 #endif /* CONFIG_TRACER_MAX_TRACE */
5913
__tracing_resize_ring_buffer(struct trace_array * tr,unsigned long size,int cpu)5914 static int __tracing_resize_ring_buffer(struct trace_array *tr,
5915 unsigned long size, int cpu)
5916 {
5917 int ret;
5918
5919 /*
5920 * If kernel or user changes the size of the ring buffer
5921 * we use the size that was given, and we can forget about
5922 * expanding it later.
5923 */
5924 trace_set_ring_buffer_expanded(tr);
5925
5926 /* May be called before buffers are initialized */
5927 if (!tr->array_buffer.buffer)
5928 return 0;
5929
5930 /* Do not allow tracing while resizing ring buffer */
5931 tracing_stop_tr(tr);
5932
5933 ret = ring_buffer_resize(tr->array_buffer.buffer, size, cpu);
5934 if (ret < 0)
5935 goto out_start;
5936
5937 #ifdef CONFIG_TRACER_MAX_TRACE
5938 if (!tr->allocated_snapshot)
5939 goto out;
5940
5941 ret = ring_buffer_resize(tr->max_buffer.buffer, size, cpu);
5942 if (ret < 0) {
5943 int r = resize_buffer_duplicate_size(&tr->array_buffer,
5944 &tr->array_buffer, cpu);
5945 if (r < 0) {
5946 /*
5947 * AARGH! We are left with different
5948 * size max buffer!!!!
5949 * The max buffer is our "snapshot" buffer.
5950 * When a tracer needs a snapshot (one of the
5951 * latency tracers), it swaps the max buffer
5952 * with the saved snap shot. We succeeded to
5953 * update the size of the main buffer, but failed to
5954 * update the size of the max buffer. But when we tried
5955 * to reset the main buffer to the original size, we
5956 * failed there too. This is very unlikely to
5957 * happen, but if it does, warn and kill all
5958 * tracing.
5959 */
5960 WARN_ON(1);
5961 tracing_disabled = 1;
5962 }
5963 goto out_start;
5964 }
5965
5966 update_buffer_entries(&tr->max_buffer, cpu);
5967
5968 out:
5969 #endif /* CONFIG_TRACER_MAX_TRACE */
5970
5971 update_buffer_entries(&tr->array_buffer, cpu);
5972 out_start:
5973 tracing_start_tr(tr);
5974 return ret;
5975 }
5976
tracing_resize_ring_buffer(struct trace_array * tr,unsigned long size,int cpu_id)5977 ssize_t tracing_resize_ring_buffer(struct trace_array *tr,
5978 unsigned long size, int cpu_id)
5979 {
5980 guard(mutex)(&trace_types_lock);
5981
5982 if (cpu_id != RING_BUFFER_ALL_CPUS) {
5983 /* make sure, this cpu is enabled in the mask */
5984 if (!cpumask_test_cpu(cpu_id, tracing_buffer_mask))
5985 return -EINVAL;
5986 }
5987
5988 return __tracing_resize_ring_buffer(tr, size, cpu_id);
5989 }
5990
update_last_data(struct trace_array * tr)5991 static void update_last_data(struct trace_array *tr)
5992 {
5993 if (!tr->text_delta && !tr->data_delta)
5994 return;
5995
5996 /*
5997 * Need to clear all CPU buffers as there cannot be events
5998 * from the previous boot mixed with events with this boot
5999 * as that will cause a confusing trace. Need to clear all
6000 * CPU buffers, even for those that may currently be offline.
6001 */
6002 tracing_reset_all_cpus(&tr->array_buffer);
6003
6004 /* Using current data now */
6005 tr->text_delta = 0;
6006 tr->data_delta = 0;
6007 }
6008
6009 /**
6010 * tracing_update_buffers - used by tracing facility to expand ring buffers
6011 * @tr: The tracing instance
6012 *
6013 * To save on memory when the tracing is never used on a system with it
6014 * configured in. The ring buffers are set to a minimum size. But once
6015 * a user starts to use the tracing facility, then they need to grow
6016 * to their default size.
6017 *
6018 * This function is to be called when a tracer is about to be used.
6019 */
tracing_update_buffers(struct trace_array * tr)6020 int tracing_update_buffers(struct trace_array *tr)
6021 {
6022 int ret = 0;
6023
6024 mutex_lock(&trace_types_lock);
6025
6026 update_last_data(tr);
6027
6028 if (!tr->ring_buffer_expanded)
6029 ret = __tracing_resize_ring_buffer(tr, trace_buf_size,
6030 RING_BUFFER_ALL_CPUS);
6031 mutex_unlock(&trace_types_lock);
6032
6033 return ret;
6034 }
6035
6036 struct trace_option_dentry;
6037
6038 static void
6039 create_trace_option_files(struct trace_array *tr, struct tracer *tracer);
6040
6041 /*
6042 * Used to clear out the tracer before deletion of an instance.
6043 * Must have trace_types_lock held.
6044 */
tracing_set_nop(struct trace_array * tr)6045 static void tracing_set_nop(struct trace_array *tr)
6046 {
6047 if (tr->current_trace == &nop_trace)
6048 return;
6049
6050 tr->current_trace->enabled--;
6051
6052 if (tr->current_trace->reset)
6053 tr->current_trace->reset(tr);
6054
6055 tr->current_trace = &nop_trace;
6056 }
6057
6058 static bool tracer_options_updated;
6059
add_tracer_options(struct trace_array * tr,struct tracer * t)6060 static void add_tracer_options(struct trace_array *tr, struct tracer *t)
6061 {
6062 /* Only enable if the directory has been created already. */
6063 if (!tr->dir)
6064 return;
6065
6066 /* Only create trace option files after update_tracer_options finish */
6067 if (!tracer_options_updated)
6068 return;
6069
6070 create_trace_option_files(tr, t);
6071 }
6072
tracing_set_tracer(struct trace_array * tr,const char * buf)6073 int tracing_set_tracer(struct trace_array *tr, const char *buf)
6074 {
6075 struct tracer *t;
6076 #ifdef CONFIG_TRACER_MAX_TRACE
6077 bool had_max_tr;
6078 #endif
6079 int ret;
6080
6081 guard(mutex)(&trace_types_lock);
6082
6083 update_last_data(tr);
6084
6085 if (!tr->ring_buffer_expanded) {
6086 ret = __tracing_resize_ring_buffer(tr, trace_buf_size,
6087 RING_BUFFER_ALL_CPUS);
6088 if (ret < 0)
6089 return ret;
6090 ret = 0;
6091 }
6092
6093 for (t = trace_types; t; t = t->next) {
6094 if (strcmp(t->name, buf) == 0)
6095 break;
6096 }
6097 if (!t)
6098 return -EINVAL;
6099
6100 if (t == tr->current_trace)
6101 return 0;
6102
6103 #ifdef CONFIG_TRACER_SNAPSHOT
6104 if (t->use_max_tr) {
6105 local_irq_disable();
6106 arch_spin_lock(&tr->max_lock);
6107 ret = tr->cond_snapshot ? -EBUSY : 0;
6108 arch_spin_unlock(&tr->max_lock);
6109 local_irq_enable();
6110 if (ret)
6111 return ret;
6112 }
6113 #endif
6114 /* Some tracers won't work on kernel command line */
6115 if (system_state < SYSTEM_RUNNING && t->noboot) {
6116 pr_warn("Tracer '%s' is not allowed on command line, ignored\n",
6117 t->name);
6118 return -EINVAL;
6119 }
6120
6121 /* Some tracers are only allowed for the top level buffer */
6122 if (!trace_ok_for_array(t, tr))
6123 return -EINVAL;
6124
6125 /* If trace pipe files are being read, we can't change the tracer */
6126 if (tr->trace_ref)
6127 return -EBUSY;
6128
6129 trace_branch_disable();
6130
6131 tr->current_trace->enabled--;
6132
6133 if (tr->current_trace->reset)
6134 tr->current_trace->reset(tr);
6135
6136 #ifdef CONFIG_TRACER_MAX_TRACE
6137 had_max_tr = tr->current_trace->use_max_tr;
6138
6139 /* Current trace needs to be nop_trace before synchronize_rcu */
6140 tr->current_trace = &nop_trace;
6141
6142 if (had_max_tr && !t->use_max_tr) {
6143 /*
6144 * We need to make sure that the update_max_tr sees that
6145 * current_trace changed to nop_trace to keep it from
6146 * swapping the buffers after we resize it.
6147 * The update_max_tr is called from interrupts disabled
6148 * so a synchronized_sched() is sufficient.
6149 */
6150 synchronize_rcu();
6151 free_snapshot(tr);
6152 tracing_disarm_snapshot(tr);
6153 }
6154
6155 if (!had_max_tr && t->use_max_tr) {
6156 ret = tracing_arm_snapshot_locked(tr);
6157 if (ret)
6158 return ret;
6159 }
6160 #else
6161 tr->current_trace = &nop_trace;
6162 #endif
6163
6164 if (t->init) {
6165 ret = tracer_init(t, tr);
6166 if (ret) {
6167 #ifdef CONFIG_TRACER_MAX_TRACE
6168 if (t->use_max_tr)
6169 tracing_disarm_snapshot(tr);
6170 #endif
6171 return ret;
6172 }
6173 }
6174
6175 tr->current_trace = t;
6176 tr->current_trace->enabled++;
6177 trace_branch_enable(tr);
6178
6179 return 0;
6180 }
6181
6182 static ssize_t
tracing_set_trace_write(struct file * filp,const char __user * ubuf,size_t cnt,loff_t * ppos)6183 tracing_set_trace_write(struct file *filp, const char __user *ubuf,
6184 size_t cnt, loff_t *ppos)
6185 {
6186 struct trace_array *tr = filp->private_data;
6187 char buf[MAX_TRACER_SIZE+1];
6188 char *name;
6189 size_t ret;
6190 int err;
6191
6192 ret = cnt;
6193
6194 if (cnt > MAX_TRACER_SIZE)
6195 cnt = MAX_TRACER_SIZE;
6196
6197 if (copy_from_user(buf, ubuf, cnt))
6198 return -EFAULT;
6199
6200 buf[cnt] = 0;
6201
6202 name = strim(buf);
6203
6204 err = tracing_set_tracer(tr, name);
6205 if (err)
6206 return err;
6207
6208 *ppos += ret;
6209
6210 return ret;
6211 }
6212
6213 static ssize_t
tracing_nsecs_read(unsigned long * ptr,char __user * ubuf,size_t cnt,loff_t * ppos)6214 tracing_nsecs_read(unsigned long *ptr, char __user *ubuf,
6215 size_t cnt, loff_t *ppos)
6216 {
6217 char buf[64];
6218 int r;
6219
6220 r = snprintf(buf, sizeof(buf), "%ld\n",
6221 *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
6222 if (r > sizeof(buf))
6223 r = sizeof(buf);
6224 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6225 }
6226
6227 static ssize_t
tracing_nsecs_write(unsigned long * ptr,const char __user * ubuf,size_t cnt,loff_t * ppos)6228 tracing_nsecs_write(unsigned long *ptr, const char __user *ubuf,
6229 size_t cnt, loff_t *ppos)
6230 {
6231 unsigned long val;
6232 int ret;
6233
6234 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6235 if (ret)
6236 return ret;
6237
6238 *ptr = val * 1000;
6239
6240 return cnt;
6241 }
6242
6243 static ssize_t
tracing_thresh_read(struct file * filp,char __user * ubuf,size_t cnt,loff_t * ppos)6244 tracing_thresh_read(struct file *filp, char __user *ubuf,
6245 size_t cnt, loff_t *ppos)
6246 {
6247 return tracing_nsecs_read(&tracing_thresh, ubuf, cnt, ppos);
6248 }
6249
6250 static ssize_t
tracing_thresh_write(struct file * filp,const char __user * ubuf,size_t cnt,loff_t * ppos)6251 tracing_thresh_write(struct file *filp, const char __user *ubuf,
6252 size_t cnt, loff_t *ppos)
6253 {
6254 struct trace_array *tr = filp->private_data;
6255 int ret;
6256
6257 guard(mutex)(&trace_types_lock);
6258 ret = tracing_nsecs_write(&tracing_thresh, ubuf, cnt, ppos);
6259 if (ret < 0)
6260 return ret;
6261
6262 if (tr->current_trace->update_thresh) {
6263 ret = tr->current_trace->update_thresh(tr);
6264 if (ret < 0)
6265 return ret;
6266 }
6267
6268 return cnt;
6269 }
6270
6271 #ifdef CONFIG_TRACER_MAX_TRACE
6272
6273 static ssize_t
tracing_max_lat_read(struct file * filp,char __user * ubuf,size_t cnt,loff_t * ppos)6274 tracing_max_lat_read(struct file *filp, char __user *ubuf,
6275 size_t cnt, loff_t *ppos)
6276 {
6277 struct trace_array *tr = filp->private_data;
6278
6279 return tracing_nsecs_read(&tr->max_latency, ubuf, cnt, ppos);
6280 }
6281
6282 static ssize_t
tracing_max_lat_write(struct file * filp,const char __user * ubuf,size_t cnt,loff_t * ppos)6283 tracing_max_lat_write(struct file *filp, const char __user *ubuf,
6284 size_t cnt, loff_t *ppos)
6285 {
6286 struct trace_array *tr = filp->private_data;
6287
6288 return tracing_nsecs_write(&tr->max_latency, ubuf, cnt, ppos);
6289 }
6290
6291 #endif
6292
open_pipe_on_cpu(struct trace_array * tr,int cpu)6293 static int open_pipe_on_cpu(struct trace_array *tr, int cpu)
6294 {
6295 if (cpu == RING_BUFFER_ALL_CPUS) {
6296 if (cpumask_empty(tr->pipe_cpumask)) {
6297 cpumask_setall(tr->pipe_cpumask);
6298 return 0;
6299 }
6300 } else if (!cpumask_test_cpu(cpu, tr->pipe_cpumask)) {
6301 cpumask_set_cpu(cpu, tr->pipe_cpumask);
6302 return 0;
6303 }
6304 return -EBUSY;
6305 }
6306
close_pipe_on_cpu(struct trace_array * tr,int cpu)6307 static void close_pipe_on_cpu(struct trace_array *tr, int cpu)
6308 {
6309 if (cpu == RING_BUFFER_ALL_CPUS) {
6310 WARN_ON(!cpumask_full(tr->pipe_cpumask));
6311 cpumask_clear(tr->pipe_cpumask);
6312 } else {
6313 WARN_ON(!cpumask_test_cpu(cpu, tr->pipe_cpumask));
6314 cpumask_clear_cpu(cpu, tr->pipe_cpumask);
6315 }
6316 }
6317
tracing_open_pipe(struct inode * inode,struct file * filp)6318 static int tracing_open_pipe(struct inode *inode, struct file *filp)
6319 {
6320 struct trace_array *tr = inode->i_private;
6321 struct trace_iterator *iter;
6322 int cpu;
6323 int ret;
6324
6325 ret = tracing_check_open_get_tr(tr);
6326 if (ret)
6327 return ret;
6328
6329 mutex_lock(&trace_types_lock);
6330 cpu = tracing_get_cpu(inode);
6331 ret = open_pipe_on_cpu(tr, cpu);
6332 if (ret)
6333 goto fail_pipe_on_cpu;
6334
6335 /* create a buffer to store the information to pass to userspace */
6336 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
6337 if (!iter) {
6338 ret = -ENOMEM;
6339 goto fail_alloc_iter;
6340 }
6341
6342 trace_seq_init(&iter->seq);
6343 iter->trace = tr->current_trace;
6344
6345 if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
6346 ret = -ENOMEM;
6347 goto fail;
6348 }
6349
6350 /* trace pipe does not show start of buffer */
6351 cpumask_setall(iter->started);
6352
6353 if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
6354 iter->iter_flags |= TRACE_FILE_LAT_FMT;
6355
6356 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
6357 if (trace_clocks[tr->clock_id].in_ns)
6358 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
6359
6360 iter->tr = tr;
6361 iter->array_buffer = &tr->array_buffer;
6362 iter->cpu_file = cpu;
6363 mutex_init(&iter->mutex);
6364 filp->private_data = iter;
6365
6366 if (iter->trace->pipe_open)
6367 iter->trace->pipe_open(iter);
6368
6369 nonseekable_open(inode, filp);
6370
6371 tr->trace_ref++;
6372
6373 mutex_unlock(&trace_types_lock);
6374 return ret;
6375
6376 fail:
6377 kfree(iter);
6378 fail_alloc_iter:
6379 close_pipe_on_cpu(tr, cpu);
6380 fail_pipe_on_cpu:
6381 __trace_array_put(tr);
6382 mutex_unlock(&trace_types_lock);
6383 return ret;
6384 }
6385
tracing_release_pipe(struct inode * inode,struct file * file)6386 static int tracing_release_pipe(struct inode *inode, struct file *file)
6387 {
6388 struct trace_iterator *iter = file->private_data;
6389 struct trace_array *tr = inode->i_private;
6390
6391 mutex_lock(&trace_types_lock);
6392
6393 tr->trace_ref--;
6394
6395 if (iter->trace->pipe_close)
6396 iter->trace->pipe_close(iter);
6397 close_pipe_on_cpu(tr, iter->cpu_file);
6398 mutex_unlock(&trace_types_lock);
6399
6400 free_trace_iter_content(iter);
6401 kfree(iter);
6402
6403 trace_array_put(tr);
6404
6405 return 0;
6406 }
6407
6408 static __poll_t
trace_poll(struct trace_iterator * iter,struct file * filp,poll_table * poll_table)6409 trace_poll(struct trace_iterator *iter, struct file *filp, poll_table *poll_table)
6410 {
6411 struct trace_array *tr = iter->tr;
6412
6413 /* Iterators are static, they should be filled or empty */
6414 if (trace_buffer_iter(iter, iter->cpu_file))
6415 return EPOLLIN | EPOLLRDNORM;
6416
6417 if (tr->trace_flags & TRACE_ITER_BLOCK)
6418 /*
6419 * Always select as readable when in blocking mode
6420 */
6421 return EPOLLIN | EPOLLRDNORM;
6422 else
6423 return ring_buffer_poll_wait(iter->array_buffer->buffer, iter->cpu_file,
6424 filp, poll_table, iter->tr->buffer_percent);
6425 }
6426
6427 static __poll_t
tracing_poll_pipe(struct file * filp,poll_table * poll_table)6428 tracing_poll_pipe(struct file *filp, poll_table *poll_table)
6429 {
6430 struct trace_iterator *iter = filp->private_data;
6431
6432 return trace_poll(iter, filp, poll_table);
6433 }
6434
6435 /* Must be called with iter->mutex held. */
tracing_wait_pipe(struct file * filp)6436 static int tracing_wait_pipe(struct file *filp)
6437 {
6438 struct trace_iterator *iter = filp->private_data;
6439 int ret;
6440
6441 while (trace_empty(iter)) {
6442
6443 if ((filp->f_flags & O_NONBLOCK)) {
6444 return -EAGAIN;
6445 }
6446
6447 /*
6448 * We block until we read something and tracing is disabled.
6449 * We still block if tracing is disabled, but we have never
6450 * read anything. This allows a user to cat this file, and
6451 * then enable tracing. But after we have read something,
6452 * we give an EOF when tracing is again disabled.
6453 *
6454 * iter->pos will be 0 if we haven't read anything.
6455 */
6456 if (!tracer_tracing_is_on(iter->tr) && iter->pos)
6457 break;
6458
6459 mutex_unlock(&iter->mutex);
6460
6461 ret = wait_on_pipe(iter, 0);
6462
6463 mutex_lock(&iter->mutex);
6464
6465 if (ret)
6466 return ret;
6467 }
6468
6469 return 1;
6470 }
6471
6472 /*
6473 * Consumer reader.
6474 */
6475 static ssize_t
tracing_read_pipe(struct file * filp,char __user * ubuf,size_t cnt,loff_t * ppos)6476 tracing_read_pipe(struct file *filp, char __user *ubuf,
6477 size_t cnt, loff_t *ppos)
6478 {
6479 struct trace_iterator *iter = filp->private_data;
6480 ssize_t sret;
6481
6482 /*
6483 * Avoid more than one consumer on a single file descriptor
6484 * This is just a matter of traces coherency, the ring buffer itself
6485 * is protected.
6486 */
6487 guard(mutex)(&iter->mutex);
6488
6489 /* return any leftover data */
6490 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
6491 if (sret != -EBUSY)
6492 return sret;
6493
6494 trace_seq_init(&iter->seq);
6495
6496 if (iter->trace->read) {
6497 sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
6498 if (sret)
6499 return sret;
6500 }
6501
6502 waitagain:
6503 sret = tracing_wait_pipe(filp);
6504 if (sret <= 0)
6505 return sret;
6506
6507 /* stop when tracing is finished */
6508 if (trace_empty(iter))
6509 return 0;
6510
6511 if (cnt >= TRACE_SEQ_BUFFER_SIZE)
6512 cnt = TRACE_SEQ_BUFFER_SIZE - 1;
6513
6514 /* reset all but tr, trace, and overruns */
6515 trace_iterator_reset(iter);
6516 cpumask_clear(iter->started);
6517 trace_seq_init(&iter->seq);
6518
6519 trace_event_read_lock();
6520 trace_access_lock(iter->cpu_file);
6521 while (trace_find_next_entry_inc(iter) != NULL) {
6522 enum print_line_t ret;
6523 int save_len = iter->seq.seq.len;
6524
6525 ret = print_trace_line(iter);
6526 if (ret == TRACE_TYPE_PARTIAL_LINE) {
6527 /*
6528 * If one print_trace_line() fills entire trace_seq in one shot,
6529 * trace_seq_to_user() will returns -EBUSY because save_len == 0,
6530 * In this case, we need to consume it, otherwise, loop will peek
6531 * this event next time, resulting in an infinite loop.
6532 */
6533 if (save_len == 0) {
6534 iter->seq.full = 0;
6535 trace_seq_puts(&iter->seq, "[LINE TOO BIG]\n");
6536 trace_consume(iter);
6537 break;
6538 }
6539
6540 /* In other cases, don't print partial lines */
6541 iter->seq.seq.len = save_len;
6542 break;
6543 }
6544 if (ret != TRACE_TYPE_NO_CONSUME)
6545 trace_consume(iter);
6546
6547 if (trace_seq_used(&iter->seq) >= cnt)
6548 break;
6549
6550 /*
6551 * Setting the full flag means we reached the trace_seq buffer
6552 * size and we should leave by partial output condition above.
6553 * One of the trace_seq_* functions is not used properly.
6554 */
6555 WARN_ONCE(iter->seq.full, "full flag set for trace type %d",
6556 iter->ent->type);
6557 }
6558 trace_access_unlock(iter->cpu_file);
6559 trace_event_read_unlock();
6560
6561 /* Now copy what we have to the user */
6562 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
6563 if (iter->seq.readpos >= trace_seq_used(&iter->seq))
6564 trace_seq_init(&iter->seq);
6565
6566 /*
6567 * If there was nothing to send to user, in spite of consuming trace
6568 * entries, go back to wait for more entries.
6569 */
6570 if (sret == -EBUSY)
6571 goto waitagain;
6572
6573 return sret;
6574 }
6575
tracing_spd_release_pipe(struct splice_pipe_desc * spd,unsigned int idx)6576 static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
6577 unsigned int idx)
6578 {
6579 __free_page(spd->pages[idx]);
6580 }
6581
6582 static size_t
tracing_fill_pipe_page(size_t rem,struct trace_iterator * iter)6583 tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
6584 {
6585 size_t count;
6586 int save_len;
6587 int ret;
6588
6589 /* Seq buffer is page-sized, exactly what we need. */
6590 for (;;) {
6591 save_len = iter->seq.seq.len;
6592 ret = print_trace_line(iter);
6593
6594 if (trace_seq_has_overflowed(&iter->seq)) {
6595 iter->seq.seq.len = save_len;
6596 break;
6597 }
6598
6599 /*
6600 * This should not be hit, because it should only
6601 * be set if the iter->seq overflowed. But check it
6602 * anyway to be safe.
6603 */
6604 if (ret == TRACE_TYPE_PARTIAL_LINE) {
6605 iter->seq.seq.len = save_len;
6606 break;
6607 }
6608
6609 count = trace_seq_used(&iter->seq) - save_len;
6610 if (rem < count) {
6611 rem = 0;
6612 iter->seq.seq.len = save_len;
6613 break;
6614 }
6615
6616 if (ret != TRACE_TYPE_NO_CONSUME)
6617 trace_consume(iter);
6618 rem -= count;
6619 if (!trace_find_next_entry_inc(iter)) {
6620 rem = 0;
6621 iter->ent = NULL;
6622 break;
6623 }
6624 }
6625
6626 return rem;
6627 }
6628
tracing_splice_read_pipe(struct file * filp,loff_t * ppos,struct pipe_inode_info * pipe,size_t len,unsigned int flags)6629 static ssize_t tracing_splice_read_pipe(struct file *filp,
6630 loff_t *ppos,
6631 struct pipe_inode_info *pipe,
6632 size_t len,
6633 unsigned int flags)
6634 {
6635 struct page *pages_def[PIPE_DEF_BUFFERS];
6636 struct partial_page partial_def[PIPE_DEF_BUFFERS];
6637 struct trace_iterator *iter = filp->private_data;
6638 struct splice_pipe_desc spd = {
6639 .pages = pages_def,
6640 .partial = partial_def,
6641 .nr_pages = 0, /* This gets updated below. */
6642 .nr_pages_max = PIPE_DEF_BUFFERS,
6643 .ops = &default_pipe_buf_ops,
6644 .spd_release = tracing_spd_release_pipe,
6645 };
6646 ssize_t ret;
6647 size_t rem;
6648 unsigned int i;
6649
6650 if (splice_grow_spd(pipe, &spd))
6651 return -ENOMEM;
6652
6653 mutex_lock(&iter->mutex);
6654
6655 if (iter->trace->splice_read) {
6656 ret = iter->trace->splice_read(iter, filp,
6657 ppos, pipe, len, flags);
6658 if (ret)
6659 goto out_err;
6660 }
6661
6662 ret = tracing_wait_pipe(filp);
6663 if (ret <= 0)
6664 goto out_err;
6665
6666 if (!iter->ent && !trace_find_next_entry_inc(iter)) {
6667 ret = -EFAULT;
6668 goto out_err;
6669 }
6670
6671 trace_event_read_lock();
6672 trace_access_lock(iter->cpu_file);
6673
6674 /* Fill as many pages as possible. */
6675 for (i = 0, rem = len; i < spd.nr_pages_max && rem; i++) {
6676 spd.pages[i] = alloc_page(GFP_KERNEL);
6677 if (!spd.pages[i])
6678 break;
6679
6680 rem = tracing_fill_pipe_page(rem, iter);
6681
6682 /* Copy the data into the page, so we can start over. */
6683 ret = trace_seq_to_buffer(&iter->seq,
6684 page_address(spd.pages[i]),
6685 trace_seq_used(&iter->seq));
6686 if (ret < 0) {
6687 __free_page(spd.pages[i]);
6688 break;
6689 }
6690 spd.partial[i].offset = 0;
6691 spd.partial[i].len = trace_seq_used(&iter->seq);
6692
6693 trace_seq_init(&iter->seq);
6694 }
6695
6696 trace_access_unlock(iter->cpu_file);
6697 trace_event_read_unlock();
6698 mutex_unlock(&iter->mutex);
6699
6700 spd.nr_pages = i;
6701
6702 if (i)
6703 ret = splice_to_pipe(pipe, &spd);
6704 else
6705 ret = 0;
6706 out:
6707 splice_shrink_spd(&spd);
6708 return ret;
6709
6710 out_err:
6711 mutex_unlock(&iter->mutex);
6712 goto out;
6713 }
6714
6715 static ssize_t
tracing_entries_read(struct file * filp,char __user * ubuf,size_t cnt,loff_t * ppos)6716 tracing_entries_read(struct file *filp, char __user *ubuf,
6717 size_t cnt, loff_t *ppos)
6718 {
6719 struct inode *inode = file_inode(filp);
6720 struct trace_array *tr = inode->i_private;
6721 int cpu = tracing_get_cpu(inode);
6722 char buf[64];
6723 int r = 0;
6724 ssize_t ret;
6725
6726 mutex_lock(&trace_types_lock);
6727
6728 if (cpu == RING_BUFFER_ALL_CPUS) {
6729 int cpu, buf_size_same;
6730 unsigned long size;
6731
6732 size = 0;
6733 buf_size_same = 1;
6734 /* check if all cpu sizes are same */
6735 for_each_tracing_cpu(cpu) {
6736 /* fill in the size from first enabled cpu */
6737 if (size == 0)
6738 size = per_cpu_ptr(tr->array_buffer.data, cpu)->entries;
6739 if (size != per_cpu_ptr(tr->array_buffer.data, cpu)->entries) {
6740 buf_size_same = 0;
6741 break;
6742 }
6743 }
6744
6745 if (buf_size_same) {
6746 if (!tr->ring_buffer_expanded)
6747 r = sprintf(buf, "%lu (expanded: %lu)\n",
6748 size >> 10,
6749 trace_buf_size >> 10);
6750 else
6751 r = sprintf(buf, "%lu\n", size >> 10);
6752 } else
6753 r = sprintf(buf, "X\n");
6754 } else
6755 r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->array_buffer.data, cpu)->entries >> 10);
6756
6757 mutex_unlock(&trace_types_lock);
6758
6759 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6760 return ret;
6761 }
6762
6763 static ssize_t
tracing_entries_write(struct file * filp,const char __user * ubuf,size_t cnt,loff_t * ppos)6764 tracing_entries_write(struct file *filp, const char __user *ubuf,
6765 size_t cnt, loff_t *ppos)
6766 {
6767 struct inode *inode = file_inode(filp);
6768 struct trace_array *tr = inode->i_private;
6769 unsigned long val;
6770 int ret;
6771
6772 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6773 if (ret)
6774 return ret;
6775
6776 /* must have at least 1 entry */
6777 if (!val)
6778 return -EINVAL;
6779
6780 /* value is in KB */
6781 val <<= 10;
6782 ret = tracing_resize_ring_buffer(tr, val, tracing_get_cpu(inode));
6783 if (ret < 0)
6784 return ret;
6785
6786 *ppos += cnt;
6787
6788 return cnt;
6789 }
6790
6791 static ssize_t
tracing_total_entries_read(struct file * filp,char __user * ubuf,size_t cnt,loff_t * ppos)6792 tracing_total_entries_read(struct file *filp, char __user *ubuf,
6793 size_t cnt, loff_t *ppos)
6794 {
6795 struct trace_array *tr = filp->private_data;
6796 char buf[64];
6797 int r, cpu;
6798 unsigned long size = 0, expanded_size = 0;
6799
6800 mutex_lock(&trace_types_lock);
6801 for_each_tracing_cpu(cpu) {
6802 size += per_cpu_ptr(tr->array_buffer.data, cpu)->entries >> 10;
6803 if (!tr->ring_buffer_expanded)
6804 expanded_size += trace_buf_size >> 10;
6805 }
6806 if (tr->ring_buffer_expanded)
6807 r = sprintf(buf, "%lu\n", size);
6808 else
6809 r = sprintf(buf, "%lu (expanded: %lu)\n", size, expanded_size);
6810 mutex_unlock(&trace_types_lock);
6811
6812 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6813 }
6814
6815 static ssize_t
tracing_last_boot_read(struct file * filp,char __user * ubuf,size_t cnt,loff_t * ppos)6816 tracing_last_boot_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
6817 {
6818 struct trace_array *tr = filp->private_data;
6819 struct seq_buf seq;
6820 char buf[64];
6821
6822 seq_buf_init(&seq, buf, 64);
6823
6824 seq_buf_printf(&seq, "text delta:\t%ld\n", tr->text_delta);
6825 seq_buf_printf(&seq, "data delta:\t%ld\n", tr->data_delta);
6826
6827 return simple_read_from_buffer(ubuf, cnt, ppos, buf, seq_buf_used(&seq));
6828 }
6829
tracing_buffer_meta_open(struct inode * inode,struct file * filp)6830 static int tracing_buffer_meta_open(struct inode *inode, struct file *filp)
6831 {
6832 struct trace_array *tr = inode->i_private;
6833 int cpu = tracing_get_cpu(inode);
6834 int ret;
6835
6836 ret = tracing_check_open_get_tr(tr);
6837 if (ret)
6838 return ret;
6839
6840 ret = ring_buffer_meta_seq_init(filp, tr->array_buffer.buffer, cpu);
6841 if (ret < 0)
6842 __trace_array_put(tr);
6843 return ret;
6844 }
6845
6846 static ssize_t
tracing_free_buffer_write(struct file * filp,const char __user * ubuf,size_t cnt,loff_t * ppos)6847 tracing_free_buffer_write(struct file *filp, const char __user *ubuf,
6848 size_t cnt, loff_t *ppos)
6849 {
6850 /*
6851 * There is no need to read what the user has written, this function
6852 * is just to make sure that there is no error when "echo" is used
6853 */
6854
6855 *ppos += cnt;
6856
6857 return cnt;
6858 }
6859
6860 static int
tracing_free_buffer_release(struct inode * inode,struct file * filp)6861 tracing_free_buffer_release(struct inode *inode, struct file *filp)
6862 {
6863 struct trace_array *tr = inode->i_private;
6864
6865 /* disable tracing ? */
6866 if (tr->trace_flags & TRACE_ITER_STOP_ON_FREE)
6867 tracer_tracing_off(tr);
6868 /* resize the ring buffer to 0 */
6869 tracing_resize_ring_buffer(tr, 0, RING_BUFFER_ALL_CPUS);
6870
6871 trace_array_put(tr);
6872
6873 return 0;
6874 }
6875
6876 #define TRACE_MARKER_MAX_SIZE 4096
6877
6878 static ssize_t
tracing_mark_write(struct file * filp,const char __user * ubuf,size_t cnt,loff_t * fpos)6879 tracing_mark_write(struct file *filp, const char __user *ubuf,
6880 size_t cnt, loff_t *fpos)
6881 {
6882 struct trace_array *tr = filp->private_data;
6883 struct ring_buffer_event *event;
6884 enum event_trigger_type tt = ETT_NONE;
6885 struct trace_buffer *buffer;
6886 struct print_entry *entry;
6887 int meta_size;
6888 ssize_t written;
6889 size_t size;
6890 int len;
6891
6892 /* Used in tracing_mark_raw_write() as well */
6893 #define FAULTED_STR "<faulted>"
6894 #define FAULTED_SIZE (sizeof(FAULTED_STR) - 1) /* '\0' is already accounted for */
6895
6896 if (tracing_disabled)
6897 return -EINVAL;
6898
6899 if (!(tr->trace_flags & TRACE_ITER_MARKERS))
6900 return -EINVAL;
6901
6902 if ((ssize_t)cnt < 0)
6903 return -EINVAL;
6904
6905 if (cnt > TRACE_MARKER_MAX_SIZE)
6906 cnt = TRACE_MARKER_MAX_SIZE;
6907
6908 meta_size = sizeof(*entry) + 2; /* add '\0' and possible '\n' */
6909 again:
6910 size = cnt + meta_size;
6911
6912 /* If less than "<faulted>", then make sure we can still add that */
6913 if (cnt < FAULTED_SIZE)
6914 size += FAULTED_SIZE - cnt;
6915
6916 buffer = tr->array_buffer.buffer;
6917 event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
6918 tracing_gen_ctx());
6919 if (unlikely(!event)) {
6920 /*
6921 * If the size was greater than what was allowed, then
6922 * make it smaller and try again.
6923 */
6924 if (size > ring_buffer_max_event_size(buffer)) {
6925 /* cnt < FAULTED size should never be bigger than max */
6926 if (WARN_ON_ONCE(cnt < FAULTED_SIZE))
6927 return -EBADF;
6928 cnt = ring_buffer_max_event_size(buffer) - meta_size;
6929 /* The above should only happen once */
6930 if (WARN_ON_ONCE(cnt + meta_size == size))
6931 return -EBADF;
6932 goto again;
6933 }
6934
6935 /* Ring buffer disabled, return as if not open for write */
6936 return -EBADF;
6937 }
6938
6939 entry = ring_buffer_event_data(event);
6940 entry->ip = _THIS_IP_;
6941
6942 len = __copy_from_user_inatomic(&entry->buf, ubuf, cnt);
6943 if (len) {
6944 memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE);
6945 cnt = FAULTED_SIZE;
6946 written = -EFAULT;
6947 } else
6948 written = cnt;
6949
6950 if (tr->trace_marker_file && !list_empty(&tr->trace_marker_file->triggers)) {
6951 /* do not add \n before testing triggers, but add \0 */
6952 entry->buf[cnt] = '\0';
6953 tt = event_triggers_call(tr->trace_marker_file, buffer, entry, event);
6954 }
6955
6956 if (entry->buf[cnt - 1] != '\n') {
6957 entry->buf[cnt] = '\n';
6958 entry->buf[cnt + 1] = '\0';
6959 } else
6960 entry->buf[cnt] = '\0';
6961
6962 if (static_branch_unlikely(&trace_marker_exports_enabled))
6963 ftrace_exports(event, TRACE_EXPORT_MARKER);
6964 __buffer_unlock_commit(buffer, event);
6965
6966 if (tt)
6967 event_triggers_post_call(tr->trace_marker_file, tt);
6968
6969 return written;
6970 }
6971
6972 static ssize_t
tracing_mark_raw_write(struct file * filp,const char __user * ubuf,size_t cnt,loff_t * fpos)6973 tracing_mark_raw_write(struct file *filp, const char __user *ubuf,
6974 size_t cnt, loff_t *fpos)
6975 {
6976 struct trace_array *tr = filp->private_data;
6977 struct ring_buffer_event *event;
6978 struct trace_buffer *buffer;
6979 struct raw_data_entry *entry;
6980 ssize_t written;
6981 int size;
6982 int len;
6983
6984 #define FAULT_SIZE_ID (FAULTED_SIZE + sizeof(int))
6985
6986 if (tracing_disabled)
6987 return -EINVAL;
6988
6989 if (!(tr->trace_flags & TRACE_ITER_MARKERS))
6990 return -EINVAL;
6991
6992 /* The marker must at least have a tag id */
6993 if (cnt < sizeof(unsigned int))
6994 return -EINVAL;
6995
6996 size = sizeof(*entry) + cnt;
6997 if (cnt < FAULT_SIZE_ID)
6998 size += FAULT_SIZE_ID - cnt;
6999
7000 buffer = tr->array_buffer.buffer;
7001
7002 if (size > ring_buffer_max_event_size(buffer))
7003 return -EINVAL;
7004
7005 event = __trace_buffer_lock_reserve(buffer, TRACE_RAW_DATA, size,
7006 tracing_gen_ctx());
7007 if (!event)
7008 /* Ring buffer disabled, return as if not open for write */
7009 return -EBADF;
7010
7011 entry = ring_buffer_event_data(event);
7012
7013 len = __copy_from_user_inatomic(&entry->id, ubuf, cnt);
7014 if (len) {
7015 entry->id = -1;
7016 memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE);
7017 written = -EFAULT;
7018 } else
7019 written = cnt;
7020
7021 __buffer_unlock_commit(buffer, event);
7022
7023 return written;
7024 }
7025
tracing_clock_show(struct seq_file * m,void * v)7026 static int tracing_clock_show(struct seq_file *m, void *v)
7027 {
7028 struct trace_array *tr = m->private;
7029 int i;
7030
7031 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++)
7032 seq_printf(m,
7033 "%s%s%s%s", i ? " " : "",
7034 i == tr->clock_id ? "[" : "", trace_clocks[i].name,
7035 i == tr->clock_id ? "]" : "");
7036 seq_putc(m, '\n');
7037
7038 return 0;
7039 }
7040
tracing_set_clock(struct trace_array * tr,const char * clockstr)7041 int tracing_set_clock(struct trace_array *tr, const char *clockstr)
7042 {
7043 int i;
7044
7045 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) {
7046 if (strcmp(trace_clocks[i].name, clockstr) == 0)
7047 break;
7048 }
7049 if (i == ARRAY_SIZE(trace_clocks))
7050 return -EINVAL;
7051
7052 mutex_lock(&trace_types_lock);
7053
7054 tr->clock_id = i;
7055
7056 ring_buffer_set_clock(tr->array_buffer.buffer, trace_clocks[i].func);
7057
7058 /*
7059 * New clock may not be consistent with the previous clock.
7060 * Reset the buffer so that it doesn't have incomparable timestamps.
7061 */
7062 tracing_reset_online_cpus(&tr->array_buffer);
7063
7064 #ifdef CONFIG_TRACER_MAX_TRACE
7065 if (tr->max_buffer.buffer)
7066 ring_buffer_set_clock(tr->max_buffer.buffer, trace_clocks[i].func);
7067 tracing_reset_online_cpus(&tr->max_buffer);
7068 #endif
7069
7070 mutex_unlock(&trace_types_lock);
7071
7072 return 0;
7073 }
7074
tracing_clock_write(struct file * filp,const char __user * ubuf,size_t cnt,loff_t * fpos)7075 static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf,
7076 size_t cnt, loff_t *fpos)
7077 {
7078 struct seq_file *m = filp->private_data;
7079 struct trace_array *tr = m->private;
7080 char buf[64];
7081 const char *clockstr;
7082 int ret;
7083
7084 if (cnt >= sizeof(buf))
7085 return -EINVAL;
7086
7087 if (copy_from_user(buf, ubuf, cnt))
7088 return -EFAULT;
7089
7090 buf[cnt] = 0;
7091
7092 clockstr = strstrip(buf);
7093
7094 ret = tracing_set_clock(tr, clockstr);
7095 if (ret)
7096 return ret;
7097
7098 *fpos += cnt;
7099
7100 return cnt;
7101 }
7102
tracing_clock_open(struct inode * inode,struct file * file)7103 static int tracing_clock_open(struct inode *inode, struct file *file)
7104 {
7105 struct trace_array *tr = inode->i_private;
7106 int ret;
7107
7108 ret = tracing_check_open_get_tr(tr);
7109 if (ret)
7110 return ret;
7111
7112 ret = single_open(file, tracing_clock_show, inode->i_private);
7113 if (ret < 0)
7114 trace_array_put(tr);
7115
7116 return ret;
7117 }
7118
tracing_time_stamp_mode_show(struct seq_file * m,void * v)7119 static int tracing_time_stamp_mode_show(struct seq_file *m, void *v)
7120 {
7121 struct trace_array *tr = m->private;
7122
7123 mutex_lock(&trace_types_lock);
7124
7125 if (ring_buffer_time_stamp_abs(tr->array_buffer.buffer))
7126 seq_puts(m, "delta [absolute]\n");
7127 else
7128 seq_puts(m, "[delta] absolute\n");
7129
7130 mutex_unlock(&trace_types_lock);
7131
7132 return 0;
7133 }
7134
tracing_time_stamp_mode_open(struct inode * inode,struct file * file)7135 static int tracing_time_stamp_mode_open(struct inode *inode, struct file *file)
7136 {
7137 struct trace_array *tr = inode->i_private;
7138 int ret;
7139
7140 ret = tracing_check_open_get_tr(tr);
7141 if (ret)
7142 return ret;
7143
7144 ret = single_open(file, tracing_time_stamp_mode_show, inode->i_private);
7145 if (ret < 0)
7146 trace_array_put(tr);
7147
7148 return ret;
7149 }
7150
tracing_event_time_stamp(struct trace_buffer * buffer,struct ring_buffer_event * rbe)7151 u64 tracing_event_time_stamp(struct trace_buffer *buffer, struct ring_buffer_event *rbe)
7152 {
7153 if (rbe == this_cpu_read(trace_buffered_event))
7154 return ring_buffer_time_stamp(buffer);
7155
7156 return ring_buffer_event_time_stamp(buffer, rbe);
7157 }
7158
7159 /*
7160 * Set or disable using the per CPU trace_buffer_event when possible.
7161 */
tracing_set_filter_buffering(struct trace_array * tr,bool set)7162 int tracing_set_filter_buffering(struct trace_array *tr, bool set)
7163 {
7164 guard(mutex)(&trace_types_lock);
7165
7166 if (set && tr->no_filter_buffering_ref++)
7167 return 0;
7168
7169 if (!set) {
7170 if (WARN_ON_ONCE(!tr->no_filter_buffering_ref))
7171 return -EINVAL;
7172
7173 --tr->no_filter_buffering_ref;
7174 }
7175
7176 return 0;
7177 }
7178
7179 struct ftrace_buffer_info {
7180 struct trace_iterator iter;
7181 void *spare;
7182 unsigned int spare_cpu;
7183 unsigned int spare_size;
7184 unsigned int read;
7185 };
7186
7187 #ifdef CONFIG_TRACER_SNAPSHOT
tracing_snapshot_open(struct inode * inode,struct file * file)7188 static int tracing_snapshot_open(struct inode *inode, struct file *file)
7189 {
7190 struct trace_array *tr = inode->i_private;
7191 struct trace_iterator *iter;
7192 struct seq_file *m;
7193 int ret;
7194
7195 ret = tracing_check_open_get_tr(tr);
7196 if (ret)
7197 return ret;
7198
7199 if (file->f_mode & FMODE_READ) {
7200 iter = __tracing_open(inode, file, true);
7201 if (IS_ERR(iter))
7202 ret = PTR_ERR(iter);
7203 } else {
7204 /* Writes still need the seq_file to hold the private data */
7205 ret = -ENOMEM;
7206 m = kzalloc(sizeof(*m), GFP_KERNEL);
7207 if (!m)
7208 goto out;
7209 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
7210 if (!iter) {
7211 kfree(m);
7212 goto out;
7213 }
7214 ret = 0;
7215
7216 iter->tr = tr;
7217 iter->array_buffer = &tr->max_buffer;
7218 iter->cpu_file = tracing_get_cpu(inode);
7219 m->private = iter;
7220 file->private_data = m;
7221 }
7222 out:
7223 if (ret < 0)
7224 trace_array_put(tr);
7225
7226 return ret;
7227 }
7228
tracing_swap_cpu_buffer(void * tr)7229 static void tracing_swap_cpu_buffer(void *tr)
7230 {
7231 update_max_tr_single((struct trace_array *)tr, current, smp_processor_id());
7232 }
7233
7234 static ssize_t
tracing_snapshot_write(struct file * filp,const char __user * ubuf,size_t cnt,loff_t * ppos)7235 tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
7236 loff_t *ppos)
7237 {
7238 struct seq_file *m = filp->private_data;
7239 struct trace_iterator *iter = m->private;
7240 struct trace_array *tr = iter->tr;
7241 unsigned long val;
7242 int ret;
7243
7244 ret = tracing_update_buffers(tr);
7245 if (ret < 0)
7246 return ret;
7247
7248 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
7249 if (ret)
7250 return ret;
7251
7252 guard(mutex)(&trace_types_lock);
7253
7254 if (tr->current_trace->use_max_tr)
7255 return -EBUSY;
7256
7257 local_irq_disable();
7258 arch_spin_lock(&tr->max_lock);
7259 if (tr->cond_snapshot)
7260 ret = -EBUSY;
7261 arch_spin_unlock(&tr->max_lock);
7262 local_irq_enable();
7263 if (ret)
7264 return ret;
7265
7266 switch (val) {
7267 case 0:
7268 if (iter->cpu_file != RING_BUFFER_ALL_CPUS)
7269 return -EINVAL;
7270 if (tr->allocated_snapshot)
7271 free_snapshot(tr);
7272 break;
7273 case 1:
7274 /* Only allow per-cpu swap if the ring buffer supports it */
7275 #ifndef CONFIG_RING_BUFFER_ALLOW_SWAP
7276 if (iter->cpu_file != RING_BUFFER_ALL_CPUS)
7277 return -EINVAL;
7278 #endif
7279 if (tr->allocated_snapshot)
7280 ret = resize_buffer_duplicate_size(&tr->max_buffer,
7281 &tr->array_buffer, iter->cpu_file);
7282
7283 ret = tracing_arm_snapshot_locked(tr);
7284 if (ret)
7285 return ret;
7286
7287 /* Now, we're going to swap */
7288 if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
7289 local_irq_disable();
7290 update_max_tr(tr, current, smp_processor_id(), NULL);
7291 local_irq_enable();
7292 } else {
7293 smp_call_function_single(iter->cpu_file, tracing_swap_cpu_buffer,
7294 (void *)tr, 1);
7295 }
7296 tracing_disarm_snapshot(tr);
7297 break;
7298 default:
7299 if (tr->allocated_snapshot) {
7300 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
7301 tracing_reset_online_cpus(&tr->max_buffer);
7302 else
7303 tracing_reset_cpu(&tr->max_buffer, iter->cpu_file);
7304 }
7305 break;
7306 }
7307
7308 if (ret >= 0) {
7309 *ppos += cnt;
7310 ret = cnt;
7311 }
7312
7313 return ret;
7314 }
7315
tracing_snapshot_release(struct inode * inode,struct file * file)7316 static int tracing_snapshot_release(struct inode *inode, struct file *file)
7317 {
7318 struct seq_file *m = file->private_data;
7319 int ret;
7320
7321 ret = tracing_release(inode, file);
7322
7323 if (file->f_mode & FMODE_READ)
7324 return ret;
7325
7326 /* If write only, the seq_file is just a stub */
7327 if (m)
7328 kfree(m->private);
7329 kfree(m);
7330
7331 return 0;
7332 }
7333
7334 static int tracing_buffers_open(struct inode *inode, struct file *filp);
7335 static ssize_t tracing_buffers_read(struct file *filp, char __user *ubuf,
7336 size_t count, loff_t *ppos);
7337 static int tracing_buffers_release(struct inode *inode, struct file *file);
7338 static ssize_t tracing_buffers_splice_read(struct file *file, loff_t *ppos,
7339 struct pipe_inode_info *pipe, size_t len, unsigned int flags);
7340
snapshot_raw_open(struct inode * inode,struct file * filp)7341 static int snapshot_raw_open(struct inode *inode, struct file *filp)
7342 {
7343 struct ftrace_buffer_info *info;
7344 int ret;
7345
7346 /* The following checks for tracefs lockdown */
7347 ret = tracing_buffers_open(inode, filp);
7348 if (ret < 0)
7349 return ret;
7350
7351 info = filp->private_data;
7352
7353 if (info->iter.trace->use_max_tr) {
7354 tracing_buffers_release(inode, filp);
7355 return -EBUSY;
7356 }
7357
7358 info->iter.snapshot = true;
7359 info->iter.array_buffer = &info->iter.tr->max_buffer;
7360
7361 return ret;
7362 }
7363
7364 #endif /* CONFIG_TRACER_SNAPSHOT */
7365
7366
7367 static const struct file_operations tracing_thresh_fops = {
7368 .open = tracing_open_generic,
7369 .read = tracing_thresh_read,
7370 .write = tracing_thresh_write,
7371 .llseek = generic_file_llseek,
7372 };
7373
7374 #ifdef CONFIG_TRACER_MAX_TRACE
7375 static const struct file_operations tracing_max_lat_fops = {
7376 .open = tracing_open_generic_tr,
7377 .read = tracing_max_lat_read,
7378 .write = tracing_max_lat_write,
7379 .llseek = generic_file_llseek,
7380 .release = tracing_release_generic_tr,
7381 };
7382 #endif
7383
7384 static const struct file_operations set_tracer_fops = {
7385 .open = tracing_open_generic_tr,
7386 .read = tracing_set_trace_read,
7387 .write = tracing_set_trace_write,
7388 .llseek = generic_file_llseek,
7389 .release = tracing_release_generic_tr,
7390 };
7391
7392 static const struct file_operations tracing_pipe_fops = {
7393 .open = tracing_open_pipe,
7394 .poll = tracing_poll_pipe,
7395 .read = tracing_read_pipe,
7396 .splice_read = tracing_splice_read_pipe,
7397 .release = tracing_release_pipe,
7398 };
7399
7400 static const struct file_operations tracing_entries_fops = {
7401 .open = tracing_open_generic_tr,
7402 .read = tracing_entries_read,
7403 .write = tracing_entries_write,
7404 .llseek = generic_file_llseek,
7405 .release = tracing_release_generic_tr,
7406 };
7407
7408 static const struct file_operations tracing_buffer_meta_fops = {
7409 .open = tracing_buffer_meta_open,
7410 .read = seq_read,
7411 .llseek = seq_lseek,
7412 .release = tracing_seq_release,
7413 };
7414
7415 static const struct file_operations tracing_total_entries_fops = {
7416 .open = tracing_open_generic_tr,
7417 .read = tracing_total_entries_read,
7418 .llseek = generic_file_llseek,
7419 .release = tracing_release_generic_tr,
7420 };
7421
7422 static const struct file_operations tracing_free_buffer_fops = {
7423 .open = tracing_open_generic_tr,
7424 .write = tracing_free_buffer_write,
7425 .release = tracing_free_buffer_release,
7426 };
7427
7428 static const struct file_operations tracing_mark_fops = {
7429 .open = tracing_mark_open,
7430 .write = tracing_mark_write,
7431 .release = tracing_release_generic_tr,
7432 };
7433
7434 static const struct file_operations tracing_mark_raw_fops = {
7435 .open = tracing_mark_open,
7436 .write = tracing_mark_raw_write,
7437 .release = tracing_release_generic_tr,
7438 };
7439
7440 static const struct file_operations trace_clock_fops = {
7441 .open = tracing_clock_open,
7442 .read = seq_read,
7443 .llseek = seq_lseek,
7444 .release = tracing_single_release_tr,
7445 .write = tracing_clock_write,
7446 };
7447
7448 static const struct file_operations trace_time_stamp_mode_fops = {
7449 .open = tracing_time_stamp_mode_open,
7450 .read = seq_read,
7451 .llseek = seq_lseek,
7452 .release = tracing_single_release_tr,
7453 };
7454
7455 static const struct file_operations last_boot_fops = {
7456 .open = tracing_open_generic_tr,
7457 .read = tracing_last_boot_read,
7458 .llseek = generic_file_llseek,
7459 .release = tracing_release_generic_tr,
7460 };
7461
7462 #ifdef CONFIG_TRACER_SNAPSHOT
7463 static const struct file_operations snapshot_fops = {
7464 .open = tracing_snapshot_open,
7465 .read = seq_read,
7466 .write = tracing_snapshot_write,
7467 .llseek = tracing_lseek,
7468 .release = tracing_snapshot_release,
7469 };
7470
7471 static const struct file_operations snapshot_raw_fops = {
7472 .open = snapshot_raw_open,
7473 .read = tracing_buffers_read,
7474 .release = tracing_buffers_release,
7475 .splice_read = tracing_buffers_splice_read,
7476 };
7477
7478 #endif /* CONFIG_TRACER_SNAPSHOT */
7479
7480 /*
7481 * trace_min_max_write - Write a u64 value to a trace_min_max_param struct
7482 * @filp: The active open file structure
7483 * @ubuf: The userspace provided buffer to read value into
7484 * @cnt: The maximum number of bytes to read
7485 * @ppos: The current "file" position
7486 *
7487 * This function implements the write interface for a struct trace_min_max_param.
7488 * The filp->private_data must point to a trace_min_max_param structure that
7489 * defines where to write the value, the min and the max acceptable values,
7490 * and a lock to protect the write.
7491 */
7492 static ssize_t
trace_min_max_write(struct file * filp,const char __user * ubuf,size_t cnt,loff_t * ppos)7493 trace_min_max_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos)
7494 {
7495 struct trace_min_max_param *param = filp->private_data;
7496 u64 val;
7497 int err;
7498
7499 if (!param)
7500 return -EFAULT;
7501
7502 err = kstrtoull_from_user(ubuf, cnt, 10, &val);
7503 if (err)
7504 return err;
7505
7506 if (param->lock)
7507 mutex_lock(param->lock);
7508
7509 if (param->min && val < *param->min)
7510 err = -EINVAL;
7511
7512 if (param->max && val > *param->max)
7513 err = -EINVAL;
7514
7515 if (!err)
7516 *param->val = val;
7517
7518 if (param->lock)
7519 mutex_unlock(param->lock);
7520
7521 if (err)
7522 return err;
7523
7524 return cnt;
7525 }
7526
7527 /*
7528 * trace_min_max_read - Read a u64 value from a trace_min_max_param struct
7529 * @filp: The active open file structure
7530 * @ubuf: The userspace provided buffer to read value into
7531 * @cnt: The maximum number of bytes to read
7532 * @ppos: The current "file" position
7533 *
7534 * This function implements the read interface for a struct trace_min_max_param.
7535 * The filp->private_data must point to a trace_min_max_param struct with valid
7536 * data.
7537 */
7538 static ssize_t
trace_min_max_read(struct file * filp,char __user * ubuf,size_t cnt,loff_t * ppos)7539 trace_min_max_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
7540 {
7541 struct trace_min_max_param *param = filp->private_data;
7542 char buf[U64_STR_SIZE];
7543 int len;
7544 u64 val;
7545
7546 if (!param)
7547 return -EFAULT;
7548
7549 val = *param->val;
7550
7551 if (cnt > sizeof(buf))
7552 cnt = sizeof(buf);
7553
7554 len = snprintf(buf, sizeof(buf), "%llu\n", val);
7555
7556 return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
7557 }
7558
7559 const struct file_operations trace_min_max_fops = {
7560 .open = tracing_open_generic,
7561 .read = trace_min_max_read,
7562 .write = trace_min_max_write,
7563 };
7564
7565 #define TRACING_LOG_ERRS_MAX 8
7566 #define TRACING_LOG_LOC_MAX 128
7567
7568 #define CMD_PREFIX " Command: "
7569
7570 struct err_info {
7571 const char **errs; /* ptr to loc-specific array of err strings */
7572 u8 type; /* index into errs -> specific err string */
7573 u16 pos; /* caret position */
7574 u64 ts;
7575 };
7576
7577 struct tracing_log_err {
7578 struct list_head list;
7579 struct err_info info;
7580 char loc[TRACING_LOG_LOC_MAX]; /* err location */
7581 char *cmd; /* what caused err */
7582 };
7583
7584 static DEFINE_MUTEX(tracing_err_log_lock);
7585
alloc_tracing_log_err(int len)7586 static struct tracing_log_err *alloc_tracing_log_err(int len)
7587 {
7588 struct tracing_log_err *err;
7589
7590 err = kzalloc(sizeof(*err), GFP_KERNEL);
7591 if (!err)
7592 return ERR_PTR(-ENOMEM);
7593
7594 err->cmd = kzalloc(len, GFP_KERNEL);
7595 if (!err->cmd) {
7596 kfree(err);
7597 return ERR_PTR(-ENOMEM);
7598 }
7599
7600 return err;
7601 }
7602
free_tracing_log_err(struct tracing_log_err * err)7603 static void free_tracing_log_err(struct tracing_log_err *err)
7604 {
7605 kfree(err->cmd);
7606 kfree(err);
7607 }
7608
get_tracing_log_err(struct trace_array * tr,int len)7609 static struct tracing_log_err *get_tracing_log_err(struct trace_array *tr,
7610 int len)
7611 {
7612 struct tracing_log_err *err;
7613 char *cmd;
7614
7615 if (tr->n_err_log_entries < TRACING_LOG_ERRS_MAX) {
7616 err = alloc_tracing_log_err(len);
7617 if (PTR_ERR(err) != -ENOMEM)
7618 tr->n_err_log_entries++;
7619
7620 return err;
7621 }
7622 cmd = kzalloc(len, GFP_KERNEL);
7623 if (!cmd)
7624 return ERR_PTR(-ENOMEM);
7625 err = list_first_entry(&tr->err_log, struct tracing_log_err, list);
7626 kfree(err->cmd);
7627 err->cmd = cmd;
7628 list_del(&err->list);
7629
7630 return err;
7631 }
7632
7633 /**
7634 * err_pos - find the position of a string within a command for error careting
7635 * @cmd: The tracing command that caused the error
7636 * @str: The string to position the caret at within @cmd
7637 *
7638 * Finds the position of the first occurrence of @str within @cmd. The
7639 * return value can be passed to tracing_log_err() for caret placement
7640 * within @cmd.
7641 *
7642 * Returns the index within @cmd of the first occurrence of @str or 0
7643 * if @str was not found.
7644 */
err_pos(char * cmd,const char * str)7645 unsigned int err_pos(char *cmd, const char *str)
7646 {
7647 char *found;
7648
7649 if (WARN_ON(!strlen(cmd)))
7650 return 0;
7651
7652 found = strstr(cmd, str);
7653 if (found)
7654 return found - cmd;
7655
7656 return 0;
7657 }
7658
7659 /**
7660 * tracing_log_err - write an error to the tracing error log
7661 * @tr: The associated trace array for the error (NULL for top level array)
7662 * @loc: A string describing where the error occurred
7663 * @cmd: The tracing command that caused the error
7664 * @errs: The array of loc-specific static error strings
7665 * @type: The index into errs[], which produces the specific static err string
7666 * @pos: The position the caret should be placed in the cmd
7667 *
7668 * Writes an error into tracing/error_log of the form:
7669 *
7670 * <loc>: error: <text>
7671 * Command: <cmd>
7672 * ^
7673 *
7674 * tracing/error_log is a small log file containing the last
7675 * TRACING_LOG_ERRS_MAX errors (8). Memory for errors isn't allocated
7676 * unless there has been a tracing error, and the error log can be
7677 * cleared and have its memory freed by writing the empty string in
7678 * truncation mode to it i.e. echo > tracing/error_log.
7679 *
7680 * NOTE: the @errs array along with the @type param are used to
7681 * produce a static error string - this string is not copied and saved
7682 * when the error is logged - only a pointer to it is saved. See
7683 * existing callers for examples of how static strings are typically
7684 * defined for use with tracing_log_err().
7685 */
tracing_log_err(struct trace_array * tr,const char * loc,const char * cmd,const char ** errs,u8 type,u16 pos)7686 void tracing_log_err(struct trace_array *tr,
7687 const char *loc, const char *cmd,
7688 const char **errs, u8 type, u16 pos)
7689 {
7690 struct tracing_log_err *err;
7691 int len = 0;
7692
7693 if (!tr)
7694 tr = &global_trace;
7695
7696 len += sizeof(CMD_PREFIX) + 2 * sizeof("\n") + strlen(cmd) + 1;
7697
7698 guard(mutex)(&tracing_err_log_lock);
7699
7700 err = get_tracing_log_err(tr, len);
7701 if (PTR_ERR(err) == -ENOMEM)
7702 return;
7703
7704 snprintf(err->loc, TRACING_LOG_LOC_MAX, "%s: error: ", loc);
7705 snprintf(err->cmd, len, "\n" CMD_PREFIX "%s\n", cmd);
7706
7707 err->info.errs = errs;
7708 err->info.type = type;
7709 err->info.pos = pos;
7710 err->info.ts = local_clock();
7711
7712 list_add_tail(&err->list, &tr->err_log);
7713 }
7714
clear_tracing_err_log(struct trace_array * tr)7715 static void clear_tracing_err_log(struct trace_array *tr)
7716 {
7717 struct tracing_log_err *err, *next;
7718
7719 mutex_lock(&tracing_err_log_lock);
7720 list_for_each_entry_safe(err, next, &tr->err_log, list) {
7721 list_del(&err->list);
7722 free_tracing_log_err(err);
7723 }
7724
7725 tr->n_err_log_entries = 0;
7726 mutex_unlock(&tracing_err_log_lock);
7727 }
7728
tracing_err_log_seq_start(struct seq_file * m,loff_t * pos)7729 static void *tracing_err_log_seq_start(struct seq_file *m, loff_t *pos)
7730 {
7731 struct trace_array *tr = m->private;
7732
7733 mutex_lock(&tracing_err_log_lock);
7734
7735 return seq_list_start(&tr->err_log, *pos);
7736 }
7737
tracing_err_log_seq_next(struct seq_file * m,void * v,loff_t * pos)7738 static void *tracing_err_log_seq_next(struct seq_file *m, void *v, loff_t *pos)
7739 {
7740 struct trace_array *tr = m->private;
7741
7742 return seq_list_next(v, &tr->err_log, pos);
7743 }
7744
tracing_err_log_seq_stop(struct seq_file * m,void * v)7745 static void tracing_err_log_seq_stop(struct seq_file *m, void *v)
7746 {
7747 mutex_unlock(&tracing_err_log_lock);
7748 }
7749
tracing_err_log_show_pos(struct seq_file * m,u16 pos)7750 static void tracing_err_log_show_pos(struct seq_file *m, u16 pos)
7751 {
7752 u16 i;
7753
7754 for (i = 0; i < sizeof(CMD_PREFIX) - 1; i++)
7755 seq_putc(m, ' ');
7756 for (i = 0; i < pos; i++)
7757 seq_putc(m, ' ');
7758 seq_puts(m, "^\n");
7759 }
7760
tracing_err_log_seq_show(struct seq_file * m,void * v)7761 static int tracing_err_log_seq_show(struct seq_file *m, void *v)
7762 {
7763 struct tracing_log_err *err = v;
7764
7765 if (err) {
7766 const char *err_text = err->info.errs[err->info.type];
7767 u64 sec = err->info.ts;
7768 u32 nsec;
7769
7770 nsec = do_div(sec, NSEC_PER_SEC);
7771 seq_printf(m, "[%5llu.%06u] %s%s", sec, nsec / 1000,
7772 err->loc, err_text);
7773 seq_printf(m, "%s", err->cmd);
7774 tracing_err_log_show_pos(m, err->info.pos);
7775 }
7776
7777 return 0;
7778 }
7779
7780 static const struct seq_operations tracing_err_log_seq_ops = {
7781 .start = tracing_err_log_seq_start,
7782 .next = tracing_err_log_seq_next,
7783 .stop = tracing_err_log_seq_stop,
7784 .show = tracing_err_log_seq_show
7785 };
7786
tracing_err_log_open(struct inode * inode,struct file * file)7787 static int tracing_err_log_open(struct inode *inode, struct file *file)
7788 {
7789 struct trace_array *tr = inode->i_private;
7790 int ret = 0;
7791
7792 ret = tracing_check_open_get_tr(tr);
7793 if (ret)
7794 return ret;
7795
7796 /* If this file was opened for write, then erase contents */
7797 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC))
7798 clear_tracing_err_log(tr);
7799
7800 if (file->f_mode & FMODE_READ) {
7801 ret = seq_open(file, &tracing_err_log_seq_ops);
7802 if (!ret) {
7803 struct seq_file *m = file->private_data;
7804 m->private = tr;
7805 } else {
7806 trace_array_put(tr);
7807 }
7808 }
7809 return ret;
7810 }
7811
tracing_err_log_write(struct file * file,const char __user * buffer,size_t count,loff_t * ppos)7812 static ssize_t tracing_err_log_write(struct file *file,
7813 const char __user *buffer,
7814 size_t count, loff_t *ppos)
7815 {
7816 return count;
7817 }
7818
tracing_err_log_release(struct inode * inode,struct file * file)7819 static int tracing_err_log_release(struct inode *inode, struct file *file)
7820 {
7821 struct trace_array *tr = inode->i_private;
7822
7823 trace_array_put(tr);
7824
7825 if (file->f_mode & FMODE_READ)
7826 seq_release(inode, file);
7827
7828 return 0;
7829 }
7830
7831 static const struct file_operations tracing_err_log_fops = {
7832 .open = tracing_err_log_open,
7833 .write = tracing_err_log_write,
7834 .read = seq_read,
7835 .llseek = tracing_lseek,
7836 .release = tracing_err_log_release,
7837 };
7838
tracing_buffers_open(struct inode * inode,struct file * filp)7839 static int tracing_buffers_open(struct inode *inode, struct file *filp)
7840 {
7841 struct trace_array *tr = inode->i_private;
7842 struct ftrace_buffer_info *info;
7843 int ret;
7844
7845 ret = tracing_check_open_get_tr(tr);
7846 if (ret)
7847 return ret;
7848
7849 info = kvzalloc(sizeof(*info), GFP_KERNEL);
7850 if (!info) {
7851 trace_array_put(tr);
7852 return -ENOMEM;
7853 }
7854
7855 mutex_lock(&trace_types_lock);
7856
7857 info->iter.tr = tr;
7858 info->iter.cpu_file = tracing_get_cpu(inode);
7859 info->iter.trace = tr->current_trace;
7860 info->iter.array_buffer = &tr->array_buffer;
7861 info->spare = NULL;
7862 /* Force reading ring buffer for first read */
7863 info->read = (unsigned int)-1;
7864
7865 filp->private_data = info;
7866
7867 tr->trace_ref++;
7868
7869 mutex_unlock(&trace_types_lock);
7870
7871 ret = nonseekable_open(inode, filp);
7872 if (ret < 0)
7873 trace_array_put(tr);
7874
7875 return ret;
7876 }
7877
7878 static __poll_t
tracing_buffers_poll(struct file * filp,poll_table * poll_table)7879 tracing_buffers_poll(struct file *filp, poll_table *poll_table)
7880 {
7881 struct ftrace_buffer_info *info = filp->private_data;
7882 struct trace_iterator *iter = &info->iter;
7883
7884 return trace_poll(iter, filp, poll_table);
7885 }
7886
7887 static ssize_t
tracing_buffers_read(struct file * filp,char __user * ubuf,size_t count,loff_t * ppos)7888 tracing_buffers_read(struct file *filp, char __user *ubuf,
7889 size_t count, loff_t *ppos)
7890 {
7891 struct ftrace_buffer_info *info = filp->private_data;
7892 struct trace_iterator *iter = &info->iter;
7893 void *trace_data;
7894 int page_size;
7895 ssize_t ret = 0;
7896 ssize_t size;
7897
7898 if (!count)
7899 return 0;
7900
7901 #ifdef CONFIG_TRACER_MAX_TRACE
7902 if (iter->snapshot && iter->tr->current_trace->use_max_tr)
7903 return -EBUSY;
7904 #endif
7905
7906 page_size = ring_buffer_subbuf_size_get(iter->array_buffer->buffer);
7907
7908 /* Make sure the spare matches the current sub buffer size */
7909 if (info->spare) {
7910 if (page_size != info->spare_size) {
7911 ring_buffer_free_read_page(iter->array_buffer->buffer,
7912 info->spare_cpu, info->spare);
7913 info->spare = NULL;
7914 }
7915 }
7916
7917 if (!info->spare) {
7918 info->spare = ring_buffer_alloc_read_page(iter->array_buffer->buffer,
7919 iter->cpu_file);
7920 if (IS_ERR(info->spare)) {
7921 ret = PTR_ERR(info->spare);
7922 info->spare = NULL;
7923 } else {
7924 info->spare_cpu = iter->cpu_file;
7925 info->spare_size = page_size;
7926 }
7927 }
7928 if (!info->spare)
7929 return ret;
7930
7931 /* Do we have previous read data to read? */
7932 if (info->read < page_size)
7933 goto read;
7934
7935 again:
7936 trace_access_lock(iter->cpu_file);
7937 ret = ring_buffer_read_page(iter->array_buffer->buffer,
7938 info->spare,
7939 count,
7940 iter->cpu_file, 0);
7941 trace_access_unlock(iter->cpu_file);
7942
7943 if (ret < 0) {
7944 if (trace_empty(iter) && !iter->closed) {
7945 if ((filp->f_flags & O_NONBLOCK))
7946 return -EAGAIN;
7947
7948 ret = wait_on_pipe(iter, 0);
7949 if (ret)
7950 return ret;
7951
7952 goto again;
7953 }
7954 return 0;
7955 }
7956
7957 info->read = 0;
7958 read:
7959 size = page_size - info->read;
7960 if (size > count)
7961 size = count;
7962 trace_data = ring_buffer_read_page_data(info->spare);
7963 ret = copy_to_user(ubuf, trace_data + info->read, size);
7964 if (ret == size)
7965 return -EFAULT;
7966
7967 size -= ret;
7968
7969 *ppos += size;
7970 info->read += size;
7971
7972 return size;
7973 }
7974
tracing_buffers_flush(struct file * file,fl_owner_t id)7975 static int tracing_buffers_flush(struct file *file, fl_owner_t id)
7976 {
7977 struct ftrace_buffer_info *info = file->private_data;
7978 struct trace_iterator *iter = &info->iter;
7979
7980 iter->closed = true;
7981 /* Make sure the waiters see the new wait_index */
7982 (void)atomic_fetch_inc_release(&iter->wait_index);
7983
7984 ring_buffer_wake_waiters(iter->array_buffer->buffer, iter->cpu_file);
7985
7986 return 0;
7987 }
7988
tracing_buffers_release(struct inode * inode,struct file * file)7989 static int tracing_buffers_release(struct inode *inode, struct file *file)
7990 {
7991 struct ftrace_buffer_info *info = file->private_data;
7992 struct trace_iterator *iter = &info->iter;
7993
7994 mutex_lock(&trace_types_lock);
7995
7996 iter->tr->trace_ref--;
7997
7998 __trace_array_put(iter->tr);
7999
8000 if (info->spare)
8001 ring_buffer_free_read_page(iter->array_buffer->buffer,
8002 info->spare_cpu, info->spare);
8003 kvfree(info);
8004
8005 mutex_unlock(&trace_types_lock);
8006
8007 return 0;
8008 }
8009
8010 struct buffer_ref {
8011 struct trace_buffer *buffer;
8012 void *page;
8013 int cpu;
8014 refcount_t refcount;
8015 };
8016
buffer_ref_release(struct buffer_ref * ref)8017 static void buffer_ref_release(struct buffer_ref *ref)
8018 {
8019 if (!refcount_dec_and_test(&ref->refcount))
8020 return;
8021 ring_buffer_free_read_page(ref->buffer, ref->cpu, ref->page);
8022 kfree(ref);
8023 }
8024
buffer_pipe_buf_release(struct pipe_inode_info * pipe,struct pipe_buffer * buf)8025 static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
8026 struct pipe_buffer *buf)
8027 {
8028 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
8029
8030 buffer_ref_release(ref);
8031 buf->private = 0;
8032 }
8033
buffer_pipe_buf_get(struct pipe_inode_info * pipe,struct pipe_buffer * buf)8034 static bool buffer_pipe_buf_get(struct pipe_inode_info *pipe,
8035 struct pipe_buffer *buf)
8036 {
8037 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
8038
8039 if (refcount_read(&ref->refcount) > INT_MAX/2)
8040 return false;
8041
8042 refcount_inc(&ref->refcount);
8043 return true;
8044 }
8045
8046 /* Pipe buffer operations for a buffer. */
8047 static const struct pipe_buf_operations buffer_pipe_buf_ops = {
8048 .release = buffer_pipe_buf_release,
8049 .get = buffer_pipe_buf_get,
8050 };
8051
8052 /*
8053 * Callback from splice_to_pipe(), if we need to release some pages
8054 * at the end of the spd in case we error'ed out in filling the pipe.
8055 */
buffer_spd_release(struct splice_pipe_desc * spd,unsigned int i)8056 static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
8057 {
8058 struct buffer_ref *ref =
8059 (struct buffer_ref *)spd->partial[i].private;
8060
8061 buffer_ref_release(ref);
8062 spd->partial[i].private = 0;
8063 }
8064
8065 static ssize_t
tracing_buffers_splice_read(struct file * file,loff_t * ppos,struct pipe_inode_info * pipe,size_t len,unsigned int flags)8066 tracing_buffers_splice_read(struct file *file, loff_t *ppos,
8067 struct pipe_inode_info *pipe, size_t len,
8068 unsigned int flags)
8069 {
8070 struct ftrace_buffer_info *info = file->private_data;
8071 struct trace_iterator *iter = &info->iter;
8072 struct partial_page partial_def[PIPE_DEF_BUFFERS];
8073 struct page *pages_def[PIPE_DEF_BUFFERS];
8074 struct splice_pipe_desc spd = {
8075 .pages = pages_def,
8076 .partial = partial_def,
8077 .nr_pages_max = PIPE_DEF_BUFFERS,
8078 .ops = &buffer_pipe_buf_ops,
8079 .spd_release = buffer_spd_release,
8080 };
8081 struct buffer_ref *ref;
8082 bool woken = false;
8083 int page_size;
8084 int entries, i;
8085 ssize_t ret = 0;
8086
8087 #ifdef CONFIG_TRACER_MAX_TRACE
8088 if (iter->snapshot && iter->tr->current_trace->use_max_tr)
8089 return -EBUSY;
8090 #endif
8091
8092 page_size = ring_buffer_subbuf_size_get(iter->array_buffer->buffer);
8093 if (*ppos & (page_size - 1))
8094 return -EINVAL;
8095
8096 if (len & (page_size - 1)) {
8097 if (len < page_size)
8098 return -EINVAL;
8099 len &= (~(page_size - 1));
8100 }
8101
8102 if (splice_grow_spd(pipe, &spd))
8103 return -ENOMEM;
8104
8105 again:
8106 trace_access_lock(iter->cpu_file);
8107 entries = ring_buffer_entries_cpu(iter->array_buffer->buffer, iter->cpu_file);
8108
8109 for (i = 0; i < spd.nr_pages_max && len && entries; i++, len -= page_size) {
8110 struct page *page;
8111 int r;
8112
8113 ref = kzalloc(sizeof(*ref), GFP_KERNEL);
8114 if (!ref) {
8115 ret = -ENOMEM;
8116 break;
8117 }
8118
8119 refcount_set(&ref->refcount, 1);
8120 ref->buffer = iter->array_buffer->buffer;
8121 ref->page = ring_buffer_alloc_read_page(ref->buffer, iter->cpu_file);
8122 if (IS_ERR(ref->page)) {
8123 ret = PTR_ERR(ref->page);
8124 ref->page = NULL;
8125 kfree(ref);
8126 break;
8127 }
8128 ref->cpu = iter->cpu_file;
8129
8130 r = ring_buffer_read_page(ref->buffer, ref->page,
8131 len, iter->cpu_file, 1);
8132 if (r < 0) {
8133 ring_buffer_free_read_page(ref->buffer, ref->cpu,
8134 ref->page);
8135 kfree(ref);
8136 break;
8137 }
8138
8139 page = virt_to_page(ring_buffer_read_page_data(ref->page));
8140
8141 spd.pages[i] = page;
8142 spd.partial[i].len = page_size;
8143 spd.partial[i].offset = 0;
8144 spd.partial[i].private = (unsigned long)ref;
8145 spd.nr_pages++;
8146 *ppos += page_size;
8147
8148 entries = ring_buffer_entries_cpu(iter->array_buffer->buffer, iter->cpu_file);
8149 }
8150
8151 trace_access_unlock(iter->cpu_file);
8152 spd.nr_pages = i;
8153
8154 /* did we read anything? */
8155 if (!spd.nr_pages) {
8156
8157 if (ret)
8158 goto out;
8159
8160 if (woken)
8161 goto out;
8162
8163 ret = -EAGAIN;
8164 if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK))
8165 goto out;
8166
8167 ret = wait_on_pipe(iter, iter->snapshot ? 0 : iter->tr->buffer_percent);
8168 if (ret)
8169 goto out;
8170
8171 /* No need to wait after waking up when tracing is off */
8172 if (!tracer_tracing_is_on(iter->tr))
8173 goto out;
8174
8175 /* Iterate one more time to collect any new data then exit */
8176 woken = true;
8177
8178 goto again;
8179 }
8180
8181 ret = splice_to_pipe(pipe, &spd);
8182 out:
8183 splice_shrink_spd(&spd);
8184
8185 return ret;
8186 }
8187
tracing_buffers_ioctl(struct file * file,unsigned int cmd,unsigned long arg)8188 static long tracing_buffers_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
8189 {
8190 struct ftrace_buffer_info *info = file->private_data;
8191 struct trace_iterator *iter = &info->iter;
8192 int err;
8193
8194 if (cmd == TRACE_MMAP_IOCTL_GET_READER) {
8195 if (!(file->f_flags & O_NONBLOCK)) {
8196 err = ring_buffer_wait(iter->array_buffer->buffer,
8197 iter->cpu_file,
8198 iter->tr->buffer_percent,
8199 NULL, NULL);
8200 if (err)
8201 return err;
8202 }
8203
8204 return ring_buffer_map_get_reader(iter->array_buffer->buffer,
8205 iter->cpu_file);
8206 } else if (cmd) {
8207 return -ENOTTY;
8208 }
8209
8210 /*
8211 * An ioctl call with cmd 0 to the ring buffer file will wake up all
8212 * waiters
8213 */
8214 mutex_lock(&trace_types_lock);
8215
8216 /* Make sure the waiters see the new wait_index */
8217 (void)atomic_fetch_inc_release(&iter->wait_index);
8218
8219 ring_buffer_wake_waiters(iter->array_buffer->buffer, iter->cpu_file);
8220
8221 mutex_unlock(&trace_types_lock);
8222 return 0;
8223 }
8224
8225 #ifdef CONFIG_TRACER_MAX_TRACE
get_snapshot_map(struct trace_array * tr)8226 static int get_snapshot_map(struct trace_array *tr)
8227 {
8228 int err = 0;
8229
8230 /*
8231 * Called with mmap_lock held. lockdep would be unhappy if we would now
8232 * take trace_types_lock. Instead use the specific
8233 * snapshot_trigger_lock.
8234 */
8235 spin_lock(&tr->snapshot_trigger_lock);
8236
8237 if (tr->snapshot || tr->mapped == UINT_MAX)
8238 err = -EBUSY;
8239 else
8240 tr->mapped++;
8241
8242 spin_unlock(&tr->snapshot_trigger_lock);
8243
8244 /* Wait for update_max_tr() to observe iter->tr->mapped */
8245 if (tr->mapped == 1)
8246 synchronize_rcu();
8247
8248 return err;
8249
8250 }
put_snapshot_map(struct trace_array * tr)8251 static void put_snapshot_map(struct trace_array *tr)
8252 {
8253 spin_lock(&tr->snapshot_trigger_lock);
8254 if (!WARN_ON(!tr->mapped))
8255 tr->mapped--;
8256 spin_unlock(&tr->snapshot_trigger_lock);
8257 }
8258 #else
get_snapshot_map(struct trace_array * tr)8259 static inline int get_snapshot_map(struct trace_array *tr) { return 0; }
put_snapshot_map(struct trace_array * tr)8260 static inline void put_snapshot_map(struct trace_array *tr) { }
8261 #endif
8262
tracing_buffers_mmap_close(struct vm_area_struct * vma)8263 static void tracing_buffers_mmap_close(struct vm_area_struct *vma)
8264 {
8265 struct ftrace_buffer_info *info = vma->vm_file->private_data;
8266 struct trace_iterator *iter = &info->iter;
8267
8268 WARN_ON(ring_buffer_unmap(iter->array_buffer->buffer, iter->cpu_file));
8269 put_snapshot_map(iter->tr);
8270 }
8271
8272 static const struct vm_operations_struct tracing_buffers_vmops = {
8273 .close = tracing_buffers_mmap_close,
8274 };
8275
tracing_buffers_mmap(struct file * filp,struct vm_area_struct * vma)8276 static int tracing_buffers_mmap(struct file *filp, struct vm_area_struct *vma)
8277 {
8278 struct ftrace_buffer_info *info = filp->private_data;
8279 struct trace_iterator *iter = &info->iter;
8280 int ret = 0;
8281
8282 /* Currently the boot mapped buffer is not supported for mmap */
8283 if (iter->tr->flags & TRACE_ARRAY_FL_BOOT)
8284 return -ENODEV;
8285
8286 ret = get_snapshot_map(iter->tr);
8287 if (ret)
8288 return ret;
8289
8290 ret = ring_buffer_map(iter->array_buffer->buffer, iter->cpu_file, vma);
8291 if (ret)
8292 put_snapshot_map(iter->tr);
8293
8294 vma->vm_ops = &tracing_buffers_vmops;
8295
8296 return ret;
8297 }
8298
8299 static const struct file_operations tracing_buffers_fops = {
8300 .open = tracing_buffers_open,
8301 .read = tracing_buffers_read,
8302 .poll = tracing_buffers_poll,
8303 .release = tracing_buffers_release,
8304 .flush = tracing_buffers_flush,
8305 .splice_read = tracing_buffers_splice_read,
8306 .unlocked_ioctl = tracing_buffers_ioctl,
8307 .mmap = tracing_buffers_mmap,
8308 };
8309
8310 static ssize_t
tracing_stats_read(struct file * filp,char __user * ubuf,size_t count,loff_t * ppos)8311 tracing_stats_read(struct file *filp, char __user *ubuf,
8312 size_t count, loff_t *ppos)
8313 {
8314 struct inode *inode = file_inode(filp);
8315 struct trace_array *tr = inode->i_private;
8316 struct array_buffer *trace_buf = &tr->array_buffer;
8317 int cpu = tracing_get_cpu(inode);
8318 struct trace_seq *s;
8319 unsigned long cnt;
8320 unsigned long long t;
8321 unsigned long usec_rem;
8322
8323 s = kmalloc(sizeof(*s), GFP_KERNEL);
8324 if (!s)
8325 return -ENOMEM;
8326
8327 trace_seq_init(s);
8328
8329 cnt = ring_buffer_entries_cpu(trace_buf->buffer, cpu);
8330 trace_seq_printf(s, "entries: %ld\n", cnt);
8331
8332 cnt = ring_buffer_overrun_cpu(trace_buf->buffer, cpu);
8333 trace_seq_printf(s, "overrun: %ld\n", cnt);
8334
8335 cnt = ring_buffer_commit_overrun_cpu(trace_buf->buffer, cpu);
8336 trace_seq_printf(s, "commit overrun: %ld\n", cnt);
8337
8338 cnt = ring_buffer_bytes_cpu(trace_buf->buffer, cpu);
8339 trace_seq_printf(s, "bytes: %ld\n", cnt);
8340
8341 if (trace_clocks[tr->clock_id].in_ns) {
8342 /* local or global for trace_clock */
8343 t = ns2usecs(ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
8344 usec_rem = do_div(t, USEC_PER_SEC);
8345 trace_seq_printf(s, "oldest event ts: %5llu.%06lu\n",
8346 t, usec_rem);
8347
8348 t = ns2usecs(ring_buffer_time_stamp(trace_buf->buffer));
8349 usec_rem = do_div(t, USEC_PER_SEC);
8350 trace_seq_printf(s, "now ts: %5llu.%06lu\n", t, usec_rem);
8351 } else {
8352 /* counter or tsc mode for trace_clock */
8353 trace_seq_printf(s, "oldest event ts: %llu\n",
8354 ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
8355
8356 trace_seq_printf(s, "now ts: %llu\n",
8357 ring_buffer_time_stamp(trace_buf->buffer));
8358 }
8359
8360 cnt = ring_buffer_dropped_events_cpu(trace_buf->buffer, cpu);
8361 trace_seq_printf(s, "dropped events: %ld\n", cnt);
8362
8363 cnt = ring_buffer_read_events_cpu(trace_buf->buffer, cpu);
8364 trace_seq_printf(s, "read events: %ld\n", cnt);
8365
8366 count = simple_read_from_buffer(ubuf, count, ppos,
8367 s->buffer, trace_seq_used(s));
8368
8369 kfree(s);
8370
8371 return count;
8372 }
8373
8374 static const struct file_operations tracing_stats_fops = {
8375 .open = tracing_open_generic_tr,
8376 .read = tracing_stats_read,
8377 .llseek = generic_file_llseek,
8378 .release = tracing_release_generic_tr,
8379 };
8380
8381 #ifdef CONFIG_DYNAMIC_FTRACE
8382
8383 static ssize_t
tracing_read_dyn_info(struct file * filp,char __user * ubuf,size_t cnt,loff_t * ppos)8384 tracing_read_dyn_info(struct file *filp, char __user *ubuf,
8385 size_t cnt, loff_t *ppos)
8386 {
8387 ssize_t ret;
8388 char *buf;
8389 int r;
8390
8391 /* 512 should be plenty to hold the amount needed */
8392 #define DYN_INFO_BUF_SIZE 512
8393
8394 buf = kmalloc(DYN_INFO_BUF_SIZE, GFP_KERNEL);
8395 if (!buf)
8396 return -ENOMEM;
8397
8398 r = scnprintf(buf, DYN_INFO_BUF_SIZE,
8399 "%ld pages:%ld groups: %ld\n"
8400 "ftrace boot update time = %llu (ns)\n"
8401 "ftrace module total update time = %llu (ns)\n",
8402 ftrace_update_tot_cnt,
8403 ftrace_number_of_pages,
8404 ftrace_number_of_groups,
8405 ftrace_update_time,
8406 ftrace_total_mod_time);
8407
8408 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
8409 kfree(buf);
8410 return ret;
8411 }
8412
8413 static const struct file_operations tracing_dyn_info_fops = {
8414 .open = tracing_open_generic,
8415 .read = tracing_read_dyn_info,
8416 .llseek = generic_file_llseek,
8417 };
8418 #endif /* CONFIG_DYNAMIC_FTRACE */
8419
8420 #if defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE)
8421 static void
ftrace_snapshot(unsigned long ip,unsigned long parent_ip,struct trace_array * tr,struct ftrace_probe_ops * ops,void * data)8422 ftrace_snapshot(unsigned long ip, unsigned long parent_ip,
8423 struct trace_array *tr, struct ftrace_probe_ops *ops,
8424 void *data)
8425 {
8426 tracing_snapshot_instance(tr);
8427 }
8428
8429 static void
ftrace_count_snapshot(unsigned long ip,unsigned long parent_ip,struct trace_array * tr,struct ftrace_probe_ops * ops,void * data)8430 ftrace_count_snapshot(unsigned long ip, unsigned long parent_ip,
8431 struct trace_array *tr, struct ftrace_probe_ops *ops,
8432 void *data)
8433 {
8434 struct ftrace_func_mapper *mapper = data;
8435 long *count = NULL;
8436
8437 if (mapper)
8438 count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
8439
8440 if (count) {
8441
8442 if (*count <= 0)
8443 return;
8444
8445 (*count)--;
8446 }
8447
8448 tracing_snapshot_instance(tr);
8449 }
8450
8451 static int
ftrace_snapshot_print(struct seq_file * m,unsigned long ip,struct ftrace_probe_ops * ops,void * data)8452 ftrace_snapshot_print(struct seq_file *m, unsigned long ip,
8453 struct ftrace_probe_ops *ops, void *data)
8454 {
8455 struct ftrace_func_mapper *mapper = data;
8456 long *count = NULL;
8457
8458 seq_printf(m, "%ps:", (void *)ip);
8459
8460 seq_puts(m, "snapshot");
8461
8462 if (mapper)
8463 count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
8464
8465 if (count)
8466 seq_printf(m, ":count=%ld\n", *count);
8467 else
8468 seq_puts(m, ":unlimited\n");
8469
8470 return 0;
8471 }
8472
8473 static int
ftrace_snapshot_init(struct ftrace_probe_ops * ops,struct trace_array * tr,unsigned long ip,void * init_data,void ** data)8474 ftrace_snapshot_init(struct ftrace_probe_ops *ops, struct trace_array *tr,
8475 unsigned long ip, void *init_data, void **data)
8476 {
8477 struct ftrace_func_mapper *mapper = *data;
8478
8479 if (!mapper) {
8480 mapper = allocate_ftrace_func_mapper();
8481 if (!mapper)
8482 return -ENOMEM;
8483 *data = mapper;
8484 }
8485
8486 return ftrace_func_mapper_add_ip(mapper, ip, init_data);
8487 }
8488
8489 static void
ftrace_snapshot_free(struct ftrace_probe_ops * ops,struct trace_array * tr,unsigned long ip,void * data)8490 ftrace_snapshot_free(struct ftrace_probe_ops *ops, struct trace_array *tr,
8491 unsigned long ip, void *data)
8492 {
8493 struct ftrace_func_mapper *mapper = data;
8494
8495 if (!ip) {
8496 if (!mapper)
8497 return;
8498 free_ftrace_func_mapper(mapper, NULL);
8499 return;
8500 }
8501
8502 ftrace_func_mapper_remove_ip(mapper, ip);
8503 }
8504
8505 static struct ftrace_probe_ops snapshot_probe_ops = {
8506 .func = ftrace_snapshot,
8507 .print = ftrace_snapshot_print,
8508 };
8509
8510 static struct ftrace_probe_ops snapshot_count_probe_ops = {
8511 .func = ftrace_count_snapshot,
8512 .print = ftrace_snapshot_print,
8513 .init = ftrace_snapshot_init,
8514 .free = ftrace_snapshot_free,
8515 };
8516
8517 static int
ftrace_trace_snapshot_callback(struct trace_array * tr,struct ftrace_hash * hash,char * glob,char * cmd,char * param,int enable)8518 ftrace_trace_snapshot_callback(struct trace_array *tr, struct ftrace_hash *hash,
8519 char *glob, char *cmd, char *param, int enable)
8520 {
8521 struct ftrace_probe_ops *ops;
8522 void *count = (void *)-1;
8523 char *number;
8524 int ret;
8525
8526 if (!tr)
8527 return -ENODEV;
8528
8529 /* hash funcs only work with set_ftrace_filter */
8530 if (!enable)
8531 return -EINVAL;
8532
8533 ops = param ? &snapshot_count_probe_ops : &snapshot_probe_ops;
8534
8535 if (glob[0] == '!') {
8536 ret = unregister_ftrace_function_probe_func(glob+1, tr, ops);
8537 if (!ret)
8538 tracing_disarm_snapshot(tr);
8539
8540 return ret;
8541 }
8542
8543 if (!param)
8544 goto out_reg;
8545
8546 number = strsep(¶m, ":");
8547
8548 if (!strlen(number))
8549 goto out_reg;
8550
8551 /*
8552 * We use the callback data field (which is a pointer)
8553 * as our counter.
8554 */
8555 ret = kstrtoul(number, 0, (unsigned long *)&count);
8556 if (ret)
8557 return ret;
8558
8559 out_reg:
8560 ret = tracing_arm_snapshot(tr);
8561 if (ret < 0)
8562 goto out;
8563
8564 ret = register_ftrace_function_probe(glob, tr, ops, count);
8565 if (ret < 0)
8566 tracing_disarm_snapshot(tr);
8567 out:
8568 return ret < 0 ? ret : 0;
8569 }
8570
8571 static struct ftrace_func_command ftrace_snapshot_cmd = {
8572 .name = "snapshot",
8573 .func = ftrace_trace_snapshot_callback,
8574 };
8575
register_snapshot_cmd(void)8576 static __init int register_snapshot_cmd(void)
8577 {
8578 return register_ftrace_command(&ftrace_snapshot_cmd);
8579 }
8580 #else
register_snapshot_cmd(void)8581 static inline __init int register_snapshot_cmd(void) { return 0; }
8582 #endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
8583
tracing_get_dentry(struct trace_array * tr)8584 static struct dentry *tracing_get_dentry(struct trace_array *tr)
8585 {
8586 if (WARN_ON(!tr->dir))
8587 return ERR_PTR(-ENODEV);
8588
8589 /* Top directory uses NULL as the parent */
8590 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
8591 return NULL;
8592
8593 /* All sub buffers have a descriptor */
8594 return tr->dir;
8595 }
8596
tracing_dentry_percpu(struct trace_array * tr,int cpu)8597 static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu)
8598 {
8599 struct dentry *d_tracer;
8600
8601 if (tr->percpu_dir)
8602 return tr->percpu_dir;
8603
8604 d_tracer = tracing_get_dentry(tr);
8605 if (IS_ERR(d_tracer))
8606 return NULL;
8607
8608 tr->percpu_dir = tracefs_create_dir("per_cpu", d_tracer);
8609
8610 MEM_FAIL(!tr->percpu_dir,
8611 "Could not create tracefs directory 'per_cpu/%d'\n", cpu);
8612
8613 return tr->percpu_dir;
8614 }
8615
8616 static struct dentry *
trace_create_cpu_file(const char * name,umode_t mode,struct dentry * parent,void * data,long cpu,const struct file_operations * fops)8617 trace_create_cpu_file(const char *name, umode_t mode, struct dentry *parent,
8618 void *data, long cpu, const struct file_operations *fops)
8619 {
8620 struct dentry *ret = trace_create_file(name, mode, parent, data, fops);
8621
8622 if (ret) /* See tracing_get_cpu() */
8623 d_inode(ret)->i_cdev = (void *)(cpu + 1);
8624 return ret;
8625 }
8626
8627 static void
tracing_init_tracefs_percpu(struct trace_array * tr,long cpu)8628 tracing_init_tracefs_percpu(struct trace_array *tr, long cpu)
8629 {
8630 struct dentry *d_percpu = tracing_dentry_percpu(tr, cpu);
8631 struct dentry *d_cpu;
8632 char cpu_dir[30]; /* 30 characters should be more than enough */
8633
8634 if (!d_percpu)
8635 return;
8636
8637 snprintf(cpu_dir, 30, "cpu%ld", cpu);
8638 d_cpu = tracefs_create_dir(cpu_dir, d_percpu);
8639 if (!d_cpu) {
8640 pr_warn("Could not create tracefs '%s' entry\n", cpu_dir);
8641 return;
8642 }
8643
8644 /* per cpu trace_pipe */
8645 trace_create_cpu_file("trace_pipe", TRACE_MODE_READ, d_cpu,
8646 tr, cpu, &tracing_pipe_fops);
8647
8648 /* per cpu trace */
8649 trace_create_cpu_file("trace", TRACE_MODE_WRITE, d_cpu,
8650 tr, cpu, &tracing_fops);
8651
8652 trace_create_cpu_file("trace_pipe_raw", TRACE_MODE_READ, d_cpu,
8653 tr, cpu, &tracing_buffers_fops);
8654
8655 trace_create_cpu_file("stats", TRACE_MODE_READ, d_cpu,
8656 tr, cpu, &tracing_stats_fops);
8657
8658 trace_create_cpu_file("buffer_size_kb", TRACE_MODE_READ, d_cpu,
8659 tr, cpu, &tracing_entries_fops);
8660
8661 if (tr->range_addr_start)
8662 trace_create_cpu_file("buffer_meta", TRACE_MODE_READ, d_cpu,
8663 tr, cpu, &tracing_buffer_meta_fops);
8664 #ifdef CONFIG_TRACER_SNAPSHOT
8665 if (!tr->range_addr_start) {
8666 trace_create_cpu_file("snapshot", TRACE_MODE_WRITE, d_cpu,
8667 tr, cpu, &snapshot_fops);
8668
8669 trace_create_cpu_file("snapshot_raw", TRACE_MODE_READ, d_cpu,
8670 tr, cpu, &snapshot_raw_fops);
8671 }
8672 #endif
8673 }
8674
8675 #ifdef CONFIG_FTRACE_SELFTEST
8676 /* Let selftest have access to static functions in this file */
8677 #include "trace_selftest.c"
8678 #endif
8679
8680 static ssize_t
trace_options_read(struct file * filp,char __user * ubuf,size_t cnt,loff_t * ppos)8681 trace_options_read(struct file *filp, char __user *ubuf, size_t cnt,
8682 loff_t *ppos)
8683 {
8684 struct trace_option_dentry *topt = filp->private_data;
8685 char *buf;
8686
8687 if (topt->flags->val & topt->opt->bit)
8688 buf = "1\n";
8689 else
8690 buf = "0\n";
8691
8692 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
8693 }
8694
8695 static ssize_t
trace_options_write(struct file * filp,const char __user * ubuf,size_t cnt,loff_t * ppos)8696 trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt,
8697 loff_t *ppos)
8698 {
8699 struct trace_option_dentry *topt = filp->private_data;
8700 unsigned long val;
8701 int ret;
8702
8703 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
8704 if (ret)
8705 return ret;
8706
8707 if (val != 0 && val != 1)
8708 return -EINVAL;
8709
8710 if (!!(topt->flags->val & topt->opt->bit) != val) {
8711 mutex_lock(&trace_types_lock);
8712 ret = __set_tracer_option(topt->tr, topt->flags,
8713 topt->opt, !val);
8714 mutex_unlock(&trace_types_lock);
8715 if (ret)
8716 return ret;
8717 }
8718
8719 *ppos += cnt;
8720
8721 return cnt;
8722 }
8723
tracing_open_options(struct inode * inode,struct file * filp)8724 static int tracing_open_options(struct inode *inode, struct file *filp)
8725 {
8726 struct trace_option_dentry *topt = inode->i_private;
8727 int ret;
8728
8729 ret = tracing_check_open_get_tr(topt->tr);
8730 if (ret)
8731 return ret;
8732
8733 filp->private_data = inode->i_private;
8734 return 0;
8735 }
8736
tracing_release_options(struct inode * inode,struct file * file)8737 static int tracing_release_options(struct inode *inode, struct file *file)
8738 {
8739 struct trace_option_dentry *topt = file->private_data;
8740
8741 trace_array_put(topt->tr);
8742 return 0;
8743 }
8744
8745 static const struct file_operations trace_options_fops = {
8746 .open = tracing_open_options,
8747 .read = trace_options_read,
8748 .write = trace_options_write,
8749 .llseek = generic_file_llseek,
8750 .release = tracing_release_options,
8751 };
8752
8753 /*
8754 * In order to pass in both the trace_array descriptor as well as the index
8755 * to the flag that the trace option file represents, the trace_array
8756 * has a character array of trace_flags_index[], which holds the index
8757 * of the bit for the flag it represents. index[0] == 0, index[1] == 1, etc.
8758 * The address of this character array is passed to the flag option file
8759 * read/write callbacks.
8760 *
8761 * In order to extract both the index and the trace_array descriptor,
8762 * get_tr_index() uses the following algorithm.
8763 *
8764 * idx = *ptr;
8765 *
8766 * As the pointer itself contains the address of the index (remember
8767 * index[1] == 1).
8768 *
8769 * Then to get the trace_array descriptor, by subtracting that index
8770 * from the ptr, we get to the start of the index itself.
8771 *
8772 * ptr - idx == &index[0]
8773 *
8774 * Then a simple container_of() from that pointer gets us to the
8775 * trace_array descriptor.
8776 */
get_tr_index(void * data,struct trace_array ** ptr,unsigned int * pindex)8777 static void get_tr_index(void *data, struct trace_array **ptr,
8778 unsigned int *pindex)
8779 {
8780 *pindex = *(unsigned char *)data;
8781
8782 *ptr = container_of(data - *pindex, struct trace_array,
8783 trace_flags_index);
8784 }
8785
8786 static ssize_t
trace_options_core_read(struct file * filp,char __user * ubuf,size_t cnt,loff_t * ppos)8787 trace_options_core_read(struct file *filp, char __user *ubuf, size_t cnt,
8788 loff_t *ppos)
8789 {
8790 void *tr_index = filp->private_data;
8791 struct trace_array *tr;
8792 unsigned int index;
8793 char *buf;
8794
8795 get_tr_index(tr_index, &tr, &index);
8796
8797 if (tr->trace_flags & (1 << index))
8798 buf = "1\n";
8799 else
8800 buf = "0\n";
8801
8802 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
8803 }
8804
8805 static ssize_t
trace_options_core_write(struct file * filp,const char __user * ubuf,size_t cnt,loff_t * ppos)8806 trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
8807 loff_t *ppos)
8808 {
8809 void *tr_index = filp->private_data;
8810 struct trace_array *tr;
8811 unsigned int index;
8812 unsigned long val;
8813 int ret;
8814
8815 get_tr_index(tr_index, &tr, &index);
8816
8817 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
8818 if (ret)
8819 return ret;
8820
8821 if (val != 0 && val != 1)
8822 return -EINVAL;
8823
8824 mutex_lock(&event_mutex);
8825 mutex_lock(&trace_types_lock);
8826 ret = set_tracer_flag(tr, 1 << index, val);
8827 mutex_unlock(&trace_types_lock);
8828 mutex_unlock(&event_mutex);
8829
8830 if (ret < 0)
8831 return ret;
8832
8833 *ppos += cnt;
8834
8835 return cnt;
8836 }
8837
8838 static const struct file_operations trace_options_core_fops = {
8839 .open = tracing_open_generic,
8840 .read = trace_options_core_read,
8841 .write = trace_options_core_write,
8842 .llseek = generic_file_llseek,
8843 };
8844
trace_create_file(const char * name,umode_t mode,struct dentry * parent,void * data,const struct file_operations * fops)8845 struct dentry *trace_create_file(const char *name,
8846 umode_t mode,
8847 struct dentry *parent,
8848 void *data,
8849 const struct file_operations *fops)
8850 {
8851 struct dentry *ret;
8852
8853 ret = tracefs_create_file(name, mode, parent, data, fops);
8854 if (!ret)
8855 pr_warn("Could not create tracefs '%s' entry\n", name);
8856
8857 return ret;
8858 }
8859
8860
trace_options_init_dentry(struct trace_array * tr)8861 static struct dentry *trace_options_init_dentry(struct trace_array *tr)
8862 {
8863 struct dentry *d_tracer;
8864
8865 if (tr->options)
8866 return tr->options;
8867
8868 d_tracer = tracing_get_dentry(tr);
8869 if (IS_ERR(d_tracer))
8870 return NULL;
8871
8872 tr->options = tracefs_create_dir("options", d_tracer);
8873 if (!tr->options) {
8874 pr_warn("Could not create tracefs directory 'options'\n");
8875 return NULL;
8876 }
8877
8878 return tr->options;
8879 }
8880
8881 static void
create_trace_option_file(struct trace_array * tr,struct trace_option_dentry * topt,struct tracer_flags * flags,struct tracer_opt * opt)8882 create_trace_option_file(struct trace_array *tr,
8883 struct trace_option_dentry *topt,
8884 struct tracer_flags *flags,
8885 struct tracer_opt *opt)
8886 {
8887 struct dentry *t_options;
8888
8889 t_options = trace_options_init_dentry(tr);
8890 if (!t_options)
8891 return;
8892
8893 topt->flags = flags;
8894 topt->opt = opt;
8895 topt->tr = tr;
8896
8897 topt->entry = trace_create_file(opt->name, TRACE_MODE_WRITE,
8898 t_options, topt, &trace_options_fops);
8899
8900 }
8901
8902 static void
create_trace_option_files(struct trace_array * tr,struct tracer * tracer)8903 create_trace_option_files(struct trace_array *tr, struct tracer *tracer)
8904 {
8905 struct trace_option_dentry *topts;
8906 struct trace_options *tr_topts;
8907 struct tracer_flags *flags;
8908 struct tracer_opt *opts;
8909 int cnt;
8910 int i;
8911
8912 if (!tracer)
8913 return;
8914
8915 flags = tracer->flags;
8916
8917 if (!flags || !flags->opts)
8918 return;
8919
8920 /*
8921 * If this is an instance, only create flags for tracers
8922 * the instance may have.
8923 */
8924 if (!trace_ok_for_array(tracer, tr))
8925 return;
8926
8927 for (i = 0; i < tr->nr_topts; i++) {
8928 /* Make sure there's no duplicate flags. */
8929 if (WARN_ON_ONCE(tr->topts[i].tracer->flags == tracer->flags))
8930 return;
8931 }
8932
8933 opts = flags->opts;
8934
8935 for (cnt = 0; opts[cnt].name; cnt++)
8936 ;
8937
8938 topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL);
8939 if (!topts)
8940 return;
8941
8942 tr_topts = krealloc(tr->topts, sizeof(*tr->topts) * (tr->nr_topts + 1),
8943 GFP_KERNEL);
8944 if (!tr_topts) {
8945 kfree(topts);
8946 return;
8947 }
8948
8949 tr->topts = tr_topts;
8950 tr->topts[tr->nr_topts].tracer = tracer;
8951 tr->topts[tr->nr_topts].topts = topts;
8952 tr->nr_topts++;
8953
8954 for (cnt = 0; opts[cnt].name; cnt++) {
8955 create_trace_option_file(tr, &topts[cnt], flags,
8956 &opts[cnt]);
8957 MEM_FAIL(topts[cnt].entry == NULL,
8958 "Failed to create trace option: %s",
8959 opts[cnt].name);
8960 }
8961 }
8962
8963 static struct dentry *
create_trace_option_core_file(struct trace_array * tr,const char * option,long index)8964 create_trace_option_core_file(struct trace_array *tr,
8965 const char *option, long index)
8966 {
8967 struct dentry *t_options;
8968
8969 t_options = trace_options_init_dentry(tr);
8970 if (!t_options)
8971 return NULL;
8972
8973 return trace_create_file(option, TRACE_MODE_WRITE, t_options,
8974 (void *)&tr->trace_flags_index[index],
8975 &trace_options_core_fops);
8976 }
8977
create_trace_options_dir(struct trace_array * tr)8978 static void create_trace_options_dir(struct trace_array *tr)
8979 {
8980 struct dentry *t_options;
8981 bool top_level = tr == &global_trace;
8982 int i;
8983
8984 t_options = trace_options_init_dentry(tr);
8985 if (!t_options)
8986 return;
8987
8988 for (i = 0; trace_options[i]; i++) {
8989 if (top_level ||
8990 !((1 << i) & TOP_LEVEL_TRACE_FLAGS))
8991 create_trace_option_core_file(tr, trace_options[i], i);
8992 }
8993 }
8994
8995 static ssize_t
rb_simple_read(struct file * filp,char __user * ubuf,size_t cnt,loff_t * ppos)8996 rb_simple_read(struct file *filp, char __user *ubuf,
8997 size_t cnt, loff_t *ppos)
8998 {
8999 struct trace_array *tr = filp->private_data;
9000 char buf[64];
9001 int r;
9002
9003 r = tracer_tracing_is_on(tr);
9004 r = sprintf(buf, "%d\n", r);
9005
9006 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
9007 }
9008
9009 static ssize_t
rb_simple_write(struct file * filp,const char __user * ubuf,size_t cnt,loff_t * ppos)9010 rb_simple_write(struct file *filp, const char __user *ubuf,
9011 size_t cnt, loff_t *ppos)
9012 {
9013 struct trace_array *tr = filp->private_data;
9014 struct trace_buffer *buffer = tr->array_buffer.buffer;
9015 unsigned long val;
9016 int ret;
9017
9018 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
9019 if (ret)
9020 return ret;
9021
9022 if (buffer) {
9023 mutex_lock(&trace_types_lock);
9024 if (!!val == tracer_tracing_is_on(tr)) {
9025 val = 0; /* do nothing */
9026 } else if (val) {
9027 tracer_tracing_on(tr);
9028 if (tr->current_trace->start)
9029 tr->current_trace->start(tr);
9030 } else {
9031 tracer_tracing_off(tr);
9032 if (tr->current_trace->stop)
9033 tr->current_trace->stop(tr);
9034 /* Wake up any waiters */
9035 ring_buffer_wake_waiters(buffer, RING_BUFFER_ALL_CPUS);
9036 }
9037 mutex_unlock(&trace_types_lock);
9038 }
9039
9040 (*ppos)++;
9041
9042 return cnt;
9043 }
9044
9045 static const struct file_operations rb_simple_fops = {
9046 .open = tracing_open_generic_tr,
9047 .read = rb_simple_read,
9048 .write = rb_simple_write,
9049 .release = tracing_release_generic_tr,
9050 .llseek = default_llseek,
9051 };
9052
9053 static ssize_t
buffer_percent_read(struct file * filp,char __user * ubuf,size_t cnt,loff_t * ppos)9054 buffer_percent_read(struct file *filp, char __user *ubuf,
9055 size_t cnt, loff_t *ppos)
9056 {
9057 struct trace_array *tr = filp->private_data;
9058 char buf[64];
9059 int r;
9060
9061 r = tr->buffer_percent;
9062 r = sprintf(buf, "%d\n", r);
9063
9064 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
9065 }
9066
9067 static ssize_t
buffer_percent_write(struct file * filp,const char __user * ubuf,size_t cnt,loff_t * ppos)9068 buffer_percent_write(struct file *filp, const char __user *ubuf,
9069 size_t cnt, loff_t *ppos)
9070 {
9071 struct trace_array *tr = filp->private_data;
9072 unsigned long val;
9073 int ret;
9074
9075 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
9076 if (ret)
9077 return ret;
9078
9079 if (val > 100)
9080 return -EINVAL;
9081
9082 tr->buffer_percent = val;
9083
9084 (*ppos)++;
9085
9086 return cnt;
9087 }
9088
9089 static const struct file_operations buffer_percent_fops = {
9090 .open = tracing_open_generic_tr,
9091 .read = buffer_percent_read,
9092 .write = buffer_percent_write,
9093 .release = tracing_release_generic_tr,
9094 .llseek = default_llseek,
9095 };
9096
9097 static ssize_t
buffer_subbuf_size_read(struct file * filp,char __user * ubuf,size_t cnt,loff_t * ppos)9098 buffer_subbuf_size_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
9099 {
9100 struct trace_array *tr = filp->private_data;
9101 size_t size;
9102 char buf[64];
9103 int order;
9104 int r;
9105
9106 order = ring_buffer_subbuf_order_get(tr->array_buffer.buffer);
9107 size = (PAGE_SIZE << order) / 1024;
9108
9109 r = sprintf(buf, "%zd\n", size);
9110
9111 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
9112 }
9113
9114 static ssize_t
buffer_subbuf_size_write(struct file * filp,const char __user * ubuf,size_t cnt,loff_t * ppos)9115 buffer_subbuf_size_write(struct file *filp, const char __user *ubuf,
9116 size_t cnt, loff_t *ppos)
9117 {
9118 struct trace_array *tr = filp->private_data;
9119 unsigned long val;
9120 int old_order;
9121 int order;
9122 int pages;
9123 int ret;
9124
9125 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
9126 if (ret)
9127 return ret;
9128
9129 val *= 1024; /* value passed in is in KB */
9130
9131 pages = DIV_ROUND_UP(val, PAGE_SIZE);
9132 order = fls(pages - 1);
9133
9134 /* limit between 1 and 128 system pages */
9135 if (order < 0 || order > 7)
9136 return -EINVAL;
9137
9138 /* Do not allow tracing while changing the order of the ring buffer */
9139 tracing_stop_tr(tr);
9140
9141 old_order = ring_buffer_subbuf_order_get(tr->array_buffer.buffer);
9142 if (old_order == order)
9143 goto out;
9144
9145 ret = ring_buffer_subbuf_order_set(tr->array_buffer.buffer, order);
9146 if (ret)
9147 goto out;
9148
9149 #ifdef CONFIG_TRACER_MAX_TRACE
9150
9151 if (!tr->allocated_snapshot)
9152 goto out_max;
9153
9154 ret = ring_buffer_subbuf_order_set(tr->max_buffer.buffer, order);
9155 if (ret) {
9156 /* Put back the old order */
9157 cnt = ring_buffer_subbuf_order_set(tr->array_buffer.buffer, old_order);
9158 if (WARN_ON_ONCE(cnt)) {
9159 /*
9160 * AARGH! We are left with different orders!
9161 * The max buffer is our "snapshot" buffer.
9162 * When a tracer needs a snapshot (one of the
9163 * latency tracers), it swaps the max buffer
9164 * with the saved snap shot. We succeeded to
9165 * update the order of the main buffer, but failed to
9166 * update the order of the max buffer. But when we tried
9167 * to reset the main buffer to the original size, we
9168 * failed there too. This is very unlikely to
9169 * happen, but if it does, warn and kill all
9170 * tracing.
9171 */
9172 tracing_disabled = 1;
9173 }
9174 goto out;
9175 }
9176 out_max:
9177 #endif
9178 (*ppos)++;
9179 out:
9180 if (ret)
9181 cnt = ret;
9182 tracing_start_tr(tr);
9183 return cnt;
9184 }
9185
9186 static const struct file_operations buffer_subbuf_size_fops = {
9187 .open = tracing_open_generic_tr,
9188 .read = buffer_subbuf_size_read,
9189 .write = buffer_subbuf_size_write,
9190 .release = tracing_release_generic_tr,
9191 .llseek = default_llseek,
9192 };
9193
9194 static struct dentry *trace_instance_dir;
9195
9196 static void
9197 init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer);
9198
9199 static int
allocate_trace_buffer(struct trace_array * tr,struct array_buffer * buf,int size)9200 allocate_trace_buffer(struct trace_array *tr, struct array_buffer *buf, int size)
9201 {
9202 enum ring_buffer_flags rb_flags;
9203
9204 rb_flags = tr->trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0;
9205
9206 buf->tr = tr;
9207
9208 if (tr->range_addr_start && tr->range_addr_size) {
9209 buf->buffer = ring_buffer_alloc_range(size, rb_flags, 0,
9210 tr->range_addr_start,
9211 tr->range_addr_size);
9212
9213 ring_buffer_last_boot_delta(buf->buffer,
9214 &tr->text_delta, &tr->data_delta);
9215 /*
9216 * This is basically the same as a mapped buffer,
9217 * with the same restrictions.
9218 */
9219 tr->mapped++;
9220 } else {
9221 buf->buffer = ring_buffer_alloc(size, rb_flags);
9222 }
9223 if (!buf->buffer)
9224 return -ENOMEM;
9225
9226 buf->data = alloc_percpu(struct trace_array_cpu);
9227 if (!buf->data) {
9228 ring_buffer_free(buf->buffer);
9229 buf->buffer = NULL;
9230 return -ENOMEM;
9231 }
9232
9233 /* Allocate the first page for all buffers */
9234 set_buffer_entries(&tr->array_buffer,
9235 ring_buffer_size(tr->array_buffer.buffer, 0));
9236
9237 return 0;
9238 }
9239
free_trace_buffer(struct array_buffer * buf)9240 static void free_trace_buffer(struct array_buffer *buf)
9241 {
9242 if (buf->buffer) {
9243 ring_buffer_free(buf->buffer);
9244 buf->buffer = NULL;
9245 free_percpu(buf->data);
9246 buf->data = NULL;
9247 }
9248 }
9249
allocate_trace_buffers(struct trace_array * tr,int size)9250 static int allocate_trace_buffers(struct trace_array *tr, int size)
9251 {
9252 int ret;
9253
9254 ret = allocate_trace_buffer(tr, &tr->array_buffer, size);
9255 if (ret)
9256 return ret;
9257
9258 #ifdef CONFIG_TRACER_MAX_TRACE
9259 /* Fix mapped buffer trace arrays do not have snapshot buffers */
9260 if (tr->range_addr_start)
9261 return 0;
9262
9263 ret = allocate_trace_buffer(tr, &tr->max_buffer,
9264 allocate_snapshot ? size : 1);
9265 if (MEM_FAIL(ret, "Failed to allocate trace buffer\n")) {
9266 free_trace_buffer(&tr->array_buffer);
9267 return -ENOMEM;
9268 }
9269 tr->allocated_snapshot = allocate_snapshot;
9270
9271 allocate_snapshot = false;
9272 #endif
9273
9274 return 0;
9275 }
9276
free_trace_buffers(struct trace_array * tr)9277 static void free_trace_buffers(struct trace_array *tr)
9278 {
9279 if (!tr)
9280 return;
9281
9282 free_trace_buffer(&tr->array_buffer);
9283
9284 #ifdef CONFIG_TRACER_MAX_TRACE
9285 free_trace_buffer(&tr->max_buffer);
9286 #endif
9287 }
9288
init_trace_flags_index(struct trace_array * tr)9289 static void init_trace_flags_index(struct trace_array *tr)
9290 {
9291 int i;
9292
9293 /* Used by the trace options files */
9294 for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++)
9295 tr->trace_flags_index[i] = i;
9296 }
9297
__update_tracer_options(struct trace_array * tr)9298 static void __update_tracer_options(struct trace_array *tr)
9299 {
9300 struct tracer *t;
9301
9302 for (t = trace_types; t; t = t->next)
9303 add_tracer_options(tr, t);
9304 }
9305
update_tracer_options(struct trace_array * tr)9306 static void update_tracer_options(struct trace_array *tr)
9307 {
9308 mutex_lock(&trace_types_lock);
9309 tracer_options_updated = true;
9310 __update_tracer_options(tr);
9311 mutex_unlock(&trace_types_lock);
9312 }
9313
9314 /* Must have trace_types_lock held */
trace_array_find(const char * instance)9315 struct trace_array *trace_array_find(const char *instance)
9316 {
9317 struct trace_array *tr, *found = NULL;
9318
9319 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9320 if (tr->name && strcmp(tr->name, instance) == 0) {
9321 found = tr;
9322 break;
9323 }
9324 }
9325
9326 return found;
9327 }
9328
trace_array_find_get(const char * instance)9329 struct trace_array *trace_array_find_get(const char *instance)
9330 {
9331 struct trace_array *tr;
9332
9333 mutex_lock(&trace_types_lock);
9334 tr = trace_array_find(instance);
9335 if (tr)
9336 tr->ref++;
9337 mutex_unlock(&trace_types_lock);
9338
9339 return tr;
9340 }
9341
trace_array_create_dir(struct trace_array * tr)9342 static int trace_array_create_dir(struct trace_array *tr)
9343 {
9344 int ret;
9345
9346 tr->dir = tracefs_create_dir(tr->name, trace_instance_dir);
9347 if (!tr->dir)
9348 return -EINVAL;
9349
9350 ret = event_trace_add_tracer(tr->dir, tr);
9351 if (ret) {
9352 tracefs_remove(tr->dir);
9353 return ret;
9354 }
9355
9356 init_tracer_tracefs(tr, tr->dir);
9357 __update_tracer_options(tr);
9358
9359 return ret;
9360 }
9361
9362 static struct trace_array *
trace_array_create_systems(const char * name,const char * systems,unsigned long range_addr_start,unsigned long range_addr_size)9363 trace_array_create_systems(const char *name, const char *systems,
9364 unsigned long range_addr_start,
9365 unsigned long range_addr_size)
9366 {
9367 struct trace_array *tr;
9368 int ret;
9369
9370 ret = -ENOMEM;
9371 tr = kzalloc(sizeof(*tr), GFP_KERNEL);
9372 if (!tr)
9373 return ERR_PTR(ret);
9374
9375 tr->name = kstrdup(name, GFP_KERNEL);
9376 if (!tr->name)
9377 goto out_free_tr;
9378
9379 if (!alloc_cpumask_var(&tr->tracing_cpumask, GFP_KERNEL))
9380 goto out_free_tr;
9381
9382 if (!zalloc_cpumask_var(&tr->pipe_cpumask, GFP_KERNEL))
9383 goto out_free_tr;
9384
9385 if (systems) {
9386 tr->system_names = kstrdup_const(systems, GFP_KERNEL);
9387 if (!tr->system_names)
9388 goto out_free_tr;
9389 }
9390
9391 /* Only for boot up memory mapped ring buffers */
9392 tr->range_addr_start = range_addr_start;
9393 tr->range_addr_size = range_addr_size;
9394
9395 tr->trace_flags = global_trace.trace_flags & ~ZEROED_TRACE_FLAGS;
9396
9397 cpumask_copy(tr->tracing_cpumask, cpu_all_mask);
9398
9399 raw_spin_lock_init(&tr->start_lock);
9400
9401 tr->max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
9402 #ifdef CONFIG_TRACER_MAX_TRACE
9403 spin_lock_init(&tr->snapshot_trigger_lock);
9404 #endif
9405 tr->current_trace = &nop_trace;
9406
9407 INIT_LIST_HEAD(&tr->systems);
9408 INIT_LIST_HEAD(&tr->events);
9409 INIT_LIST_HEAD(&tr->hist_vars);
9410 INIT_LIST_HEAD(&tr->err_log);
9411
9412 #ifdef CONFIG_MODULES
9413 INIT_LIST_HEAD(&tr->mod_events);
9414 #endif
9415
9416 if (allocate_trace_buffers(tr, trace_buf_size) < 0)
9417 goto out_free_tr;
9418
9419 /* The ring buffer is defaultly expanded */
9420 trace_set_ring_buffer_expanded(tr);
9421
9422 if (ftrace_allocate_ftrace_ops(tr) < 0)
9423 goto out_free_tr;
9424
9425 ftrace_init_trace_array(tr);
9426
9427 init_trace_flags_index(tr);
9428
9429 if (trace_instance_dir) {
9430 ret = trace_array_create_dir(tr);
9431 if (ret)
9432 goto out_free_tr;
9433 } else
9434 __trace_early_add_events(tr);
9435
9436 list_add(&tr->list, &ftrace_trace_arrays);
9437
9438 tr->ref++;
9439
9440 return tr;
9441
9442 out_free_tr:
9443 ftrace_free_ftrace_ops(tr);
9444 free_trace_buffers(tr);
9445 free_cpumask_var(tr->pipe_cpumask);
9446 free_cpumask_var(tr->tracing_cpumask);
9447 kfree_const(tr->system_names);
9448 kfree(tr->name);
9449 kfree(tr);
9450
9451 return ERR_PTR(ret);
9452 }
9453
trace_array_create(const char * name)9454 static struct trace_array *trace_array_create(const char *name)
9455 {
9456 return trace_array_create_systems(name, NULL, 0, 0);
9457 }
9458
instance_mkdir(const char * name)9459 static int instance_mkdir(const char *name)
9460 {
9461 struct trace_array *tr;
9462 int ret;
9463
9464 guard(mutex)(&event_mutex);
9465 guard(mutex)(&trace_types_lock);
9466
9467 ret = -EEXIST;
9468 if (trace_array_find(name))
9469 return -EEXIST;
9470
9471 tr = trace_array_create(name);
9472
9473 ret = PTR_ERR_OR_ZERO(tr);
9474
9475 return ret;
9476 }
9477
map_pages(u64 start,u64 size)9478 static u64 map_pages(u64 start, u64 size)
9479 {
9480 struct page **pages;
9481 phys_addr_t page_start;
9482 unsigned int page_count;
9483 unsigned int i;
9484 void *vaddr;
9485
9486 page_count = DIV_ROUND_UP(size, PAGE_SIZE);
9487
9488 page_start = start;
9489 pages = kmalloc_array(page_count, sizeof(struct page *), GFP_KERNEL);
9490 if (!pages)
9491 return 0;
9492
9493 for (i = 0; i < page_count; i++) {
9494 phys_addr_t addr = page_start + i * PAGE_SIZE;
9495 pages[i] = pfn_to_page(addr >> PAGE_SHIFT);
9496 }
9497 vaddr = vmap(pages, page_count, VM_MAP, PAGE_KERNEL);
9498 kfree(pages);
9499
9500 return (u64)(unsigned long)vaddr;
9501 }
9502
9503 /**
9504 * trace_array_get_by_name - Create/Lookup a trace array, given its name.
9505 * @name: The name of the trace array to be looked up/created.
9506 * @systems: A list of systems to create event directories for (NULL for all)
9507 *
9508 * Returns pointer to trace array with given name.
9509 * NULL, if it cannot be created.
9510 *
9511 * NOTE: This function increments the reference counter associated with the
9512 * trace array returned. This makes sure it cannot be freed while in use.
9513 * Use trace_array_put() once the trace array is no longer needed.
9514 * If the trace_array is to be freed, trace_array_destroy() needs to
9515 * be called after the trace_array_put(), or simply let user space delete
9516 * it from the tracefs instances directory. But until the
9517 * trace_array_put() is called, user space can not delete it.
9518 *
9519 */
trace_array_get_by_name(const char * name,const char * systems)9520 struct trace_array *trace_array_get_by_name(const char *name, const char *systems)
9521 {
9522 struct trace_array *tr;
9523
9524 guard(mutex)(&event_mutex);
9525 guard(mutex)(&trace_types_lock);
9526
9527 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9528 if (tr->name && strcmp(tr->name, name) == 0) {
9529 tr->ref++;
9530 return tr;
9531 }
9532 }
9533
9534 tr = trace_array_create_systems(name, systems, 0, 0);
9535
9536 if (IS_ERR(tr))
9537 tr = NULL;
9538 else
9539 tr->ref++;
9540
9541 return tr;
9542 }
9543 EXPORT_SYMBOL_GPL(trace_array_get_by_name);
9544
__remove_instance(struct trace_array * tr)9545 static int __remove_instance(struct trace_array *tr)
9546 {
9547 int i;
9548
9549 /* Reference counter for a newly created trace array = 1. */
9550 if (tr->ref > 1 || (tr->current_trace && tr->trace_ref))
9551 return -EBUSY;
9552
9553 list_del(&tr->list);
9554
9555 /* Disable all the flags that were enabled coming in */
9556 for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++) {
9557 if ((1 << i) & ZEROED_TRACE_FLAGS)
9558 set_tracer_flag(tr, 1 << i, 0);
9559 }
9560
9561 if (printk_trace == tr)
9562 update_printk_trace(&global_trace);
9563
9564 tracing_set_nop(tr);
9565 clear_ftrace_function_probes(tr);
9566 event_trace_del_tracer(tr);
9567 ftrace_clear_pids(tr);
9568 ftrace_destroy_function_files(tr);
9569 tracefs_remove(tr->dir);
9570 free_percpu(tr->last_func_repeats);
9571 free_trace_buffers(tr);
9572 clear_tracing_err_log(tr);
9573
9574 for (i = 0; i < tr->nr_topts; i++) {
9575 kfree(tr->topts[i].topts);
9576 }
9577 kfree(tr->topts);
9578
9579 free_cpumask_var(tr->pipe_cpumask);
9580 free_cpumask_var(tr->tracing_cpumask);
9581 kfree_const(tr->system_names);
9582 kfree(tr->name);
9583 kfree(tr);
9584
9585 return 0;
9586 }
9587
trace_array_destroy(struct trace_array * this_tr)9588 int trace_array_destroy(struct trace_array *this_tr)
9589 {
9590 struct trace_array *tr;
9591
9592 if (!this_tr)
9593 return -EINVAL;
9594
9595 guard(mutex)(&event_mutex);
9596 guard(mutex)(&trace_types_lock);
9597
9598
9599 /* Making sure trace array exists before destroying it. */
9600 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9601 if (tr == this_tr)
9602 return __remove_instance(tr);
9603 }
9604
9605 return -ENODEV;
9606 }
9607 EXPORT_SYMBOL_GPL(trace_array_destroy);
9608
instance_rmdir(const char * name)9609 static int instance_rmdir(const char *name)
9610 {
9611 struct trace_array *tr;
9612
9613 guard(mutex)(&event_mutex);
9614 guard(mutex)(&trace_types_lock);
9615
9616 tr = trace_array_find(name);
9617 if (!tr)
9618 return -ENODEV;
9619
9620 return __remove_instance(tr);
9621 }
9622
create_trace_instances(struct dentry * d_tracer)9623 static __init void create_trace_instances(struct dentry *d_tracer)
9624 {
9625 struct trace_array *tr;
9626
9627 trace_instance_dir = tracefs_create_instance_dir("instances", d_tracer,
9628 instance_mkdir,
9629 instance_rmdir);
9630 if (MEM_FAIL(!trace_instance_dir, "Failed to create instances directory\n"))
9631 return;
9632
9633 guard(mutex)(&event_mutex);
9634 guard(mutex)(&trace_types_lock);
9635
9636 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9637 if (!tr->name)
9638 continue;
9639 if (MEM_FAIL(trace_array_create_dir(tr) < 0,
9640 "Failed to create instance directory\n"))
9641 return;
9642 }
9643 }
9644
9645 static void
init_tracer_tracefs(struct trace_array * tr,struct dentry * d_tracer)9646 init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
9647 {
9648 int cpu;
9649
9650 trace_create_file("available_tracers", TRACE_MODE_READ, d_tracer,
9651 tr, &show_traces_fops);
9652
9653 trace_create_file("current_tracer", TRACE_MODE_WRITE, d_tracer,
9654 tr, &set_tracer_fops);
9655
9656 trace_create_file("tracing_cpumask", TRACE_MODE_WRITE, d_tracer,
9657 tr, &tracing_cpumask_fops);
9658
9659 trace_create_file("trace_options", TRACE_MODE_WRITE, d_tracer,
9660 tr, &tracing_iter_fops);
9661
9662 trace_create_file("trace", TRACE_MODE_WRITE, d_tracer,
9663 tr, &tracing_fops);
9664
9665 trace_create_file("trace_pipe", TRACE_MODE_READ, d_tracer,
9666 tr, &tracing_pipe_fops);
9667
9668 trace_create_file("buffer_size_kb", TRACE_MODE_WRITE, d_tracer,
9669 tr, &tracing_entries_fops);
9670
9671 trace_create_file("buffer_total_size_kb", TRACE_MODE_READ, d_tracer,
9672 tr, &tracing_total_entries_fops);
9673
9674 trace_create_file("free_buffer", 0200, d_tracer,
9675 tr, &tracing_free_buffer_fops);
9676
9677 trace_create_file("trace_marker", 0220, d_tracer,
9678 tr, &tracing_mark_fops);
9679
9680 tr->trace_marker_file = __find_event_file(tr, "ftrace", "print");
9681
9682 trace_create_file("trace_marker_raw", 0220, d_tracer,
9683 tr, &tracing_mark_raw_fops);
9684
9685 trace_create_file("trace_clock", TRACE_MODE_WRITE, d_tracer, tr,
9686 &trace_clock_fops);
9687
9688 trace_create_file("tracing_on", TRACE_MODE_WRITE, d_tracer,
9689 tr, &rb_simple_fops);
9690
9691 trace_create_file("timestamp_mode", TRACE_MODE_READ, d_tracer, tr,
9692 &trace_time_stamp_mode_fops);
9693
9694 tr->buffer_percent = 50;
9695
9696 trace_create_file("buffer_percent", TRACE_MODE_WRITE, d_tracer,
9697 tr, &buffer_percent_fops);
9698
9699 trace_create_file("buffer_subbuf_size_kb", TRACE_MODE_WRITE, d_tracer,
9700 tr, &buffer_subbuf_size_fops);
9701
9702 create_trace_options_dir(tr);
9703
9704 #ifdef CONFIG_TRACER_MAX_TRACE
9705 trace_create_maxlat_file(tr, d_tracer);
9706 #endif
9707
9708 if (ftrace_create_function_files(tr, d_tracer))
9709 MEM_FAIL(1, "Could not allocate function filter files");
9710
9711 if (tr->range_addr_start) {
9712 trace_create_file("last_boot_info", TRACE_MODE_READ, d_tracer,
9713 tr, &last_boot_fops);
9714 #ifdef CONFIG_TRACER_SNAPSHOT
9715 } else {
9716 trace_create_file("snapshot", TRACE_MODE_WRITE, d_tracer,
9717 tr, &snapshot_fops);
9718 #endif
9719 }
9720
9721 trace_create_file("error_log", TRACE_MODE_WRITE, d_tracer,
9722 tr, &tracing_err_log_fops);
9723
9724 for_each_tracing_cpu(cpu)
9725 tracing_init_tracefs_percpu(tr, cpu);
9726
9727 ftrace_init_tracefs(tr, d_tracer);
9728 }
9729
trace_automount(struct dentry * mntpt,void * ingore)9730 static struct vfsmount *trace_automount(struct dentry *mntpt, void *ingore)
9731 {
9732 struct vfsmount *mnt;
9733 struct file_system_type *type;
9734
9735 /*
9736 * To maintain backward compatibility for tools that mount
9737 * debugfs to get to the tracing facility, tracefs is automatically
9738 * mounted to the debugfs/tracing directory.
9739 */
9740 type = get_fs_type("tracefs");
9741 if (!type)
9742 return NULL;
9743 mnt = vfs_submount(mntpt, type, "tracefs", NULL);
9744 put_filesystem(type);
9745 if (IS_ERR(mnt))
9746 return NULL;
9747 mntget(mnt);
9748
9749 return mnt;
9750 }
9751
9752 /**
9753 * tracing_init_dentry - initialize top level trace array
9754 *
9755 * This is called when creating files or directories in the tracing
9756 * directory. It is called via fs_initcall() by any of the boot up code
9757 * and expects to return the dentry of the top level tracing directory.
9758 */
tracing_init_dentry(void)9759 int tracing_init_dentry(void)
9760 {
9761 struct trace_array *tr = &global_trace;
9762
9763 if (security_locked_down(LOCKDOWN_TRACEFS)) {
9764 pr_warn("Tracing disabled due to lockdown\n");
9765 return -EPERM;
9766 }
9767
9768 /* The top level trace array uses NULL as parent */
9769 if (tr->dir)
9770 return 0;
9771
9772 if (WARN_ON(!tracefs_initialized()))
9773 return -ENODEV;
9774
9775 /*
9776 * As there may still be users that expect the tracing
9777 * files to exist in debugfs/tracing, we must automount
9778 * the tracefs file system there, so older tools still
9779 * work with the newer kernel.
9780 */
9781 tr->dir = debugfs_create_automount("tracing", NULL,
9782 trace_automount, NULL);
9783
9784 return 0;
9785 }
9786
9787 extern struct trace_eval_map *__start_ftrace_eval_maps[];
9788 extern struct trace_eval_map *__stop_ftrace_eval_maps[];
9789
9790 static struct workqueue_struct *eval_map_wq __initdata;
9791 static struct work_struct eval_map_work __initdata;
9792 static struct work_struct tracerfs_init_work __initdata;
9793
eval_map_work_func(struct work_struct * work)9794 static void __init eval_map_work_func(struct work_struct *work)
9795 {
9796 int len;
9797
9798 len = __stop_ftrace_eval_maps - __start_ftrace_eval_maps;
9799 trace_insert_eval_map(NULL, __start_ftrace_eval_maps, len);
9800 }
9801
trace_eval_init(void)9802 static int __init trace_eval_init(void)
9803 {
9804 INIT_WORK(&eval_map_work, eval_map_work_func);
9805
9806 eval_map_wq = alloc_workqueue("eval_map_wq", WQ_UNBOUND, 0);
9807 if (!eval_map_wq) {
9808 pr_err("Unable to allocate eval_map_wq\n");
9809 /* Do work here */
9810 eval_map_work_func(&eval_map_work);
9811 return -ENOMEM;
9812 }
9813
9814 queue_work(eval_map_wq, &eval_map_work);
9815 return 0;
9816 }
9817
9818 subsys_initcall(trace_eval_init);
9819
trace_eval_sync(void)9820 static int __init trace_eval_sync(void)
9821 {
9822 /* Make sure the eval map updates are finished */
9823 if (eval_map_wq)
9824 destroy_workqueue(eval_map_wq);
9825 return 0;
9826 }
9827
9828 late_initcall_sync(trace_eval_sync);
9829
9830
9831 #ifdef CONFIG_MODULES
9832
module_exists(const char * module)9833 bool module_exists(const char *module)
9834 {
9835 /* All modules have the symbol __this_module */
9836 static const char this_mod[] = "__this_module";
9837 char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
9838 unsigned long val;
9839 int n;
9840
9841 n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
9842
9843 if (n > sizeof(modname) - 1)
9844 return false;
9845
9846 val = module_kallsyms_lookup_name(modname);
9847 return val != 0;
9848 }
9849
trace_module_add_evals(struct module * mod)9850 static void trace_module_add_evals(struct module *mod)
9851 {
9852 if (!mod->num_trace_evals)
9853 return;
9854
9855 /*
9856 * Modules with bad taint do not have events created, do
9857 * not bother with enums either.
9858 */
9859 if (trace_module_has_bad_taint(mod))
9860 return;
9861
9862 trace_insert_eval_map(mod, mod->trace_evals, mod->num_trace_evals);
9863 }
9864
9865 #ifdef CONFIG_TRACE_EVAL_MAP_FILE
trace_module_remove_evals(struct module * mod)9866 static void trace_module_remove_evals(struct module *mod)
9867 {
9868 union trace_eval_map_item *map;
9869 union trace_eval_map_item **last = &trace_eval_maps;
9870
9871 if (!mod->num_trace_evals)
9872 return;
9873
9874 guard(mutex)(&trace_eval_mutex);
9875
9876 map = trace_eval_maps;
9877
9878 while (map) {
9879 if (map->head.mod == mod)
9880 break;
9881 map = trace_eval_jmp_to_tail(map);
9882 last = &map->tail.next;
9883 map = map->tail.next;
9884 }
9885 if (!map)
9886 return;
9887
9888 *last = trace_eval_jmp_to_tail(map)->tail.next;
9889 kfree(map);
9890 }
9891 #else
trace_module_remove_evals(struct module * mod)9892 static inline void trace_module_remove_evals(struct module *mod) { }
9893 #endif /* CONFIG_TRACE_EVAL_MAP_FILE */
9894
trace_module_notify(struct notifier_block * self,unsigned long val,void * data)9895 static int trace_module_notify(struct notifier_block *self,
9896 unsigned long val, void *data)
9897 {
9898 struct module *mod = data;
9899
9900 switch (val) {
9901 case MODULE_STATE_COMING:
9902 trace_module_add_evals(mod);
9903 break;
9904 case MODULE_STATE_GOING:
9905 trace_module_remove_evals(mod);
9906 break;
9907 }
9908
9909 return NOTIFY_OK;
9910 }
9911
9912 static struct notifier_block trace_module_nb = {
9913 .notifier_call = trace_module_notify,
9914 .priority = 0,
9915 };
9916 #endif /* CONFIG_MODULES */
9917
tracer_init_tracefs_work_func(struct work_struct * work)9918 static __init void tracer_init_tracefs_work_func(struct work_struct *work)
9919 {
9920
9921 event_trace_init();
9922
9923 init_tracer_tracefs(&global_trace, NULL);
9924 ftrace_init_tracefs_toplevel(&global_trace, NULL);
9925
9926 trace_create_file("tracing_thresh", TRACE_MODE_WRITE, NULL,
9927 &global_trace, &tracing_thresh_fops);
9928
9929 trace_create_file("README", TRACE_MODE_READ, NULL,
9930 NULL, &tracing_readme_fops);
9931
9932 trace_create_file("saved_cmdlines", TRACE_MODE_READ, NULL,
9933 NULL, &tracing_saved_cmdlines_fops);
9934
9935 trace_create_file("saved_cmdlines_size", TRACE_MODE_WRITE, NULL,
9936 NULL, &tracing_saved_cmdlines_size_fops);
9937
9938 trace_create_file("saved_tgids", TRACE_MODE_READ, NULL,
9939 NULL, &tracing_saved_tgids_fops);
9940
9941 trace_create_eval_file(NULL);
9942
9943 #ifdef CONFIG_MODULES
9944 register_module_notifier(&trace_module_nb);
9945 #endif
9946
9947 #ifdef CONFIG_DYNAMIC_FTRACE
9948 trace_create_file("dyn_ftrace_total_info", TRACE_MODE_READ, NULL,
9949 NULL, &tracing_dyn_info_fops);
9950 #endif
9951
9952 create_trace_instances(NULL);
9953
9954 update_tracer_options(&global_trace);
9955 }
9956
tracer_init_tracefs(void)9957 static __init int tracer_init_tracefs(void)
9958 {
9959 int ret;
9960
9961 trace_access_lock_init();
9962
9963 ret = tracing_init_dentry();
9964 if (ret)
9965 return 0;
9966
9967 if (eval_map_wq) {
9968 INIT_WORK(&tracerfs_init_work, tracer_init_tracefs_work_func);
9969 queue_work(eval_map_wq, &tracerfs_init_work);
9970 } else {
9971 tracer_init_tracefs_work_func(NULL);
9972 }
9973
9974 rv_init_interface();
9975
9976 return 0;
9977 }
9978
9979 fs_initcall(tracer_init_tracefs);
9980
9981 static int trace_die_panic_handler(struct notifier_block *self,
9982 unsigned long ev, void *unused);
9983
9984 static struct notifier_block trace_panic_notifier = {
9985 .notifier_call = trace_die_panic_handler,
9986 .priority = INT_MAX - 1,
9987 };
9988
9989 static struct notifier_block trace_die_notifier = {
9990 .notifier_call = trace_die_panic_handler,
9991 .priority = INT_MAX - 1,
9992 };
9993
9994 /*
9995 * The idea is to execute the following die/panic callback early, in order
9996 * to avoid showing irrelevant information in the trace (like other panic
9997 * notifier functions); we are the 2nd to run, after hung_task/rcu_stall
9998 * warnings get disabled (to prevent potential log flooding).
9999 */
trace_die_panic_handler(struct notifier_block * self,unsigned long ev,void * unused)10000 static int trace_die_panic_handler(struct notifier_block *self,
10001 unsigned long ev, void *unused)
10002 {
10003 if (!ftrace_dump_on_oops_enabled())
10004 return NOTIFY_DONE;
10005
10006 /* The die notifier requires DIE_OOPS to trigger */
10007 if (self == &trace_die_notifier && ev != DIE_OOPS)
10008 return NOTIFY_DONE;
10009
10010 ftrace_dump(DUMP_PARAM);
10011
10012 return NOTIFY_DONE;
10013 }
10014
10015 /*
10016 * printk is set to max of 1024, we really don't need it that big.
10017 * Nothing should be printing 1000 characters anyway.
10018 */
10019 #define TRACE_MAX_PRINT 1000
10020
10021 /*
10022 * Define here KERN_TRACE so that we have one place to modify
10023 * it if we decide to change what log level the ftrace dump
10024 * should be at.
10025 */
10026 #define KERN_TRACE KERN_EMERG
10027
10028 void
trace_printk_seq(struct trace_seq * s)10029 trace_printk_seq(struct trace_seq *s)
10030 {
10031 /* Probably should print a warning here. */
10032 if (s->seq.len >= TRACE_MAX_PRINT)
10033 s->seq.len = TRACE_MAX_PRINT;
10034
10035 /*
10036 * More paranoid code. Although the buffer size is set to
10037 * PAGE_SIZE, and TRACE_MAX_PRINT is 1000, this is just
10038 * an extra layer of protection.
10039 */
10040 if (WARN_ON_ONCE(s->seq.len >= s->seq.size))
10041 s->seq.len = s->seq.size - 1;
10042
10043 /* should be zero ended, but we are paranoid. */
10044 s->buffer[s->seq.len] = 0;
10045
10046 printk(KERN_TRACE "%s", s->buffer);
10047
10048 trace_seq_init(s);
10049 }
10050
trace_init_iter(struct trace_iterator * iter,struct trace_array * tr)10051 static void trace_init_iter(struct trace_iterator *iter, struct trace_array *tr)
10052 {
10053 iter->tr = tr;
10054 iter->trace = iter->tr->current_trace;
10055 iter->cpu_file = RING_BUFFER_ALL_CPUS;
10056 iter->array_buffer = &tr->array_buffer;
10057
10058 if (iter->trace && iter->trace->open)
10059 iter->trace->open(iter);
10060
10061 /* Annotate start of buffers if we had overruns */
10062 if (ring_buffer_overruns(iter->array_buffer->buffer))
10063 iter->iter_flags |= TRACE_FILE_ANNOTATE;
10064
10065 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
10066 if (trace_clocks[iter->tr->clock_id].in_ns)
10067 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
10068
10069 /* Can not use kmalloc for iter.temp and iter.fmt */
10070 iter->temp = static_temp_buf;
10071 iter->temp_size = STATIC_TEMP_BUF_SIZE;
10072 iter->fmt = static_fmt_buf;
10073 iter->fmt_size = STATIC_FMT_BUF_SIZE;
10074 }
10075
trace_init_global_iter(struct trace_iterator * iter)10076 void trace_init_global_iter(struct trace_iterator *iter)
10077 {
10078 trace_init_iter(iter, &global_trace);
10079 }
10080
ftrace_dump_one(struct trace_array * tr,enum ftrace_dump_mode dump_mode)10081 static void ftrace_dump_one(struct trace_array *tr, enum ftrace_dump_mode dump_mode)
10082 {
10083 /* use static because iter can be a bit big for the stack */
10084 static struct trace_iterator iter;
10085 unsigned int old_userobj;
10086 unsigned long flags;
10087 int cnt = 0, cpu;
10088
10089 /*
10090 * Always turn off tracing when we dump.
10091 * We don't need to show trace output of what happens
10092 * between multiple crashes.
10093 *
10094 * If the user does a sysrq-z, then they can re-enable
10095 * tracing with echo 1 > tracing_on.
10096 */
10097 tracer_tracing_off(tr);
10098
10099 local_irq_save(flags);
10100
10101 /* Simulate the iterator */
10102 trace_init_iter(&iter, tr);
10103
10104 for_each_tracing_cpu(cpu) {
10105 atomic_inc(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
10106 }
10107
10108 old_userobj = tr->trace_flags & TRACE_ITER_SYM_USEROBJ;
10109
10110 /* don't look at user memory in panic mode */
10111 tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
10112
10113 if (dump_mode == DUMP_ORIG)
10114 iter.cpu_file = raw_smp_processor_id();
10115 else
10116 iter.cpu_file = RING_BUFFER_ALL_CPUS;
10117
10118 if (tr == &global_trace)
10119 printk(KERN_TRACE "Dumping ftrace buffer:\n");
10120 else
10121 printk(KERN_TRACE "Dumping ftrace instance %s buffer:\n", tr->name);
10122
10123 /* Did function tracer already get disabled? */
10124 if (ftrace_is_dead()) {
10125 printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
10126 printk("# MAY BE MISSING FUNCTION EVENTS\n");
10127 }
10128
10129 /*
10130 * We need to stop all tracing on all CPUS to read
10131 * the next buffer. This is a bit expensive, but is
10132 * not done often. We fill all what we can read,
10133 * and then release the locks again.
10134 */
10135
10136 while (!trace_empty(&iter)) {
10137
10138 if (!cnt)
10139 printk(KERN_TRACE "---------------------------------\n");
10140
10141 cnt++;
10142
10143 trace_iterator_reset(&iter);
10144 iter.iter_flags |= TRACE_FILE_LAT_FMT;
10145
10146 if (trace_find_next_entry_inc(&iter) != NULL) {
10147 int ret;
10148
10149 ret = print_trace_line(&iter);
10150 if (ret != TRACE_TYPE_NO_CONSUME)
10151 trace_consume(&iter);
10152 }
10153 touch_nmi_watchdog();
10154
10155 trace_printk_seq(&iter.seq);
10156 }
10157
10158 if (!cnt)
10159 printk(KERN_TRACE " (ftrace buffer empty)\n");
10160 else
10161 printk(KERN_TRACE "---------------------------------\n");
10162
10163 tr->trace_flags |= old_userobj;
10164
10165 for_each_tracing_cpu(cpu) {
10166 atomic_dec(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
10167 }
10168 local_irq_restore(flags);
10169 }
10170
ftrace_dump_by_param(void)10171 static void ftrace_dump_by_param(void)
10172 {
10173 bool first_param = true;
10174 char dump_param[MAX_TRACER_SIZE];
10175 char *buf, *token, *inst_name;
10176 struct trace_array *tr;
10177
10178 strscpy(dump_param, ftrace_dump_on_oops, MAX_TRACER_SIZE);
10179 buf = dump_param;
10180
10181 while ((token = strsep(&buf, ",")) != NULL) {
10182 if (first_param) {
10183 first_param = false;
10184 if (!strcmp("0", token))
10185 continue;
10186 else if (!strcmp("1", token)) {
10187 ftrace_dump_one(&global_trace, DUMP_ALL);
10188 continue;
10189 }
10190 else if (!strcmp("2", token) ||
10191 !strcmp("orig_cpu", token)) {
10192 ftrace_dump_one(&global_trace, DUMP_ORIG);
10193 continue;
10194 }
10195 }
10196
10197 inst_name = strsep(&token, "=");
10198 tr = trace_array_find(inst_name);
10199 if (!tr) {
10200 printk(KERN_TRACE "Instance %s not found\n", inst_name);
10201 continue;
10202 }
10203
10204 if (token && (!strcmp("2", token) ||
10205 !strcmp("orig_cpu", token)))
10206 ftrace_dump_one(tr, DUMP_ORIG);
10207 else
10208 ftrace_dump_one(tr, DUMP_ALL);
10209 }
10210 }
10211
ftrace_dump(enum ftrace_dump_mode oops_dump_mode)10212 void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
10213 {
10214 static atomic_t dump_running;
10215
10216 /* Only allow one dump user at a time. */
10217 if (atomic_inc_return(&dump_running) != 1) {
10218 atomic_dec(&dump_running);
10219 return;
10220 }
10221
10222 switch (oops_dump_mode) {
10223 case DUMP_ALL:
10224 ftrace_dump_one(&global_trace, DUMP_ALL);
10225 break;
10226 case DUMP_ORIG:
10227 ftrace_dump_one(&global_trace, DUMP_ORIG);
10228 break;
10229 case DUMP_PARAM:
10230 ftrace_dump_by_param();
10231 break;
10232 case DUMP_NONE:
10233 break;
10234 default:
10235 printk(KERN_TRACE "Bad dumping mode, switching to all CPUs dump\n");
10236 ftrace_dump_one(&global_trace, DUMP_ALL);
10237 }
10238
10239 atomic_dec(&dump_running);
10240 }
10241 EXPORT_SYMBOL_GPL(ftrace_dump);
10242
10243 #define WRITE_BUFSIZE 4096
10244
trace_parse_run_command(struct file * file,const char __user * buffer,size_t count,loff_t * ppos,int (* createfn)(const char *))10245 ssize_t trace_parse_run_command(struct file *file, const char __user *buffer,
10246 size_t count, loff_t *ppos,
10247 int (*createfn)(const char *))
10248 {
10249 char *kbuf, *buf, *tmp;
10250 int ret = 0;
10251 size_t done = 0;
10252 size_t size;
10253
10254 kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
10255 if (!kbuf)
10256 return -ENOMEM;
10257
10258 while (done < count) {
10259 size = count - done;
10260
10261 if (size >= WRITE_BUFSIZE)
10262 size = WRITE_BUFSIZE - 1;
10263
10264 if (copy_from_user(kbuf, buffer + done, size)) {
10265 ret = -EFAULT;
10266 goto out;
10267 }
10268 kbuf[size] = '\0';
10269 buf = kbuf;
10270 do {
10271 tmp = strchr(buf, '\n');
10272 if (tmp) {
10273 *tmp = '\0';
10274 size = tmp - buf + 1;
10275 } else {
10276 size = strlen(buf);
10277 if (done + size < count) {
10278 if (buf != kbuf)
10279 break;
10280 /* This can accept WRITE_BUFSIZE - 2 ('\n' + '\0') */
10281 pr_warn("Line length is too long: Should be less than %d\n",
10282 WRITE_BUFSIZE - 2);
10283 ret = -EINVAL;
10284 goto out;
10285 }
10286 }
10287 done += size;
10288
10289 /* Remove comments */
10290 tmp = strchr(buf, '#');
10291
10292 if (tmp)
10293 *tmp = '\0';
10294
10295 ret = createfn(buf);
10296 if (ret)
10297 goto out;
10298 buf += size;
10299
10300 } while (done < count);
10301 }
10302 ret = done;
10303
10304 out:
10305 kfree(kbuf);
10306
10307 return ret;
10308 }
10309
10310 #ifdef CONFIG_TRACER_MAX_TRACE
tr_needs_alloc_snapshot(const char * name)10311 __init static bool tr_needs_alloc_snapshot(const char *name)
10312 {
10313 char *test;
10314 int len = strlen(name);
10315 bool ret;
10316
10317 if (!boot_snapshot_index)
10318 return false;
10319
10320 if (strncmp(name, boot_snapshot_info, len) == 0 &&
10321 boot_snapshot_info[len] == '\t')
10322 return true;
10323
10324 test = kmalloc(strlen(name) + 3, GFP_KERNEL);
10325 if (!test)
10326 return false;
10327
10328 sprintf(test, "\t%s\t", name);
10329 ret = strstr(boot_snapshot_info, test) == NULL;
10330 kfree(test);
10331 return ret;
10332 }
10333
do_allocate_snapshot(const char * name)10334 __init static void do_allocate_snapshot(const char *name)
10335 {
10336 if (!tr_needs_alloc_snapshot(name))
10337 return;
10338
10339 /*
10340 * When allocate_snapshot is set, the next call to
10341 * allocate_trace_buffers() (called by trace_array_get_by_name())
10342 * will allocate the snapshot buffer. That will alse clear
10343 * this flag.
10344 */
10345 allocate_snapshot = true;
10346 }
10347 #else
do_allocate_snapshot(const char * name)10348 static inline void do_allocate_snapshot(const char *name) { }
10349 #endif
10350
enable_instances(void)10351 __init static void enable_instances(void)
10352 {
10353 struct trace_array *tr;
10354 char *curr_str;
10355 char *name;
10356 char *str;
10357 char *tok;
10358
10359 /* A tab is always appended */
10360 boot_instance_info[boot_instance_index - 1] = '\0';
10361 str = boot_instance_info;
10362
10363 while ((curr_str = strsep(&str, "\t"))) {
10364 phys_addr_t start = 0;
10365 phys_addr_t size = 0;
10366 unsigned long addr = 0;
10367 bool traceprintk = false;
10368 bool traceoff = false;
10369 char *flag_delim;
10370 char *addr_delim;
10371
10372 tok = strsep(&curr_str, ",");
10373
10374 flag_delim = strchr(tok, '^');
10375 addr_delim = strchr(tok, '@');
10376
10377 if (addr_delim)
10378 *addr_delim++ = '\0';
10379
10380 if (flag_delim)
10381 *flag_delim++ = '\0';
10382
10383 name = tok;
10384
10385 if (flag_delim) {
10386 char *flag;
10387
10388 while ((flag = strsep(&flag_delim, "^"))) {
10389 if (strcmp(flag, "traceoff") == 0) {
10390 traceoff = true;
10391 } else if ((strcmp(flag, "printk") == 0) ||
10392 (strcmp(flag, "traceprintk") == 0) ||
10393 (strcmp(flag, "trace_printk") == 0)) {
10394 traceprintk = true;
10395 } else {
10396 pr_info("Tracing: Invalid instance flag '%s' for %s\n",
10397 flag, name);
10398 }
10399 }
10400 }
10401
10402 tok = addr_delim;
10403 if (tok && isdigit(*tok)) {
10404 start = memparse(tok, &tok);
10405 if (!start) {
10406 pr_warn("Tracing: Invalid boot instance address for %s\n",
10407 name);
10408 continue;
10409 }
10410 if (*tok != ':') {
10411 pr_warn("Tracing: No size specified for instance %s\n", name);
10412 continue;
10413 }
10414 tok++;
10415 size = memparse(tok, &tok);
10416 if (!size) {
10417 pr_warn("Tracing: Invalid boot instance size for %s\n",
10418 name);
10419 continue;
10420 }
10421 } else if (tok) {
10422 if (!reserve_mem_find_by_name(tok, &start, &size)) {
10423 start = 0;
10424 pr_warn("Failed to map boot instance %s to %s\n", name, tok);
10425 continue;
10426 }
10427 }
10428
10429 if (start) {
10430 addr = map_pages(start, size);
10431 if (addr) {
10432 pr_info("Tracing: mapped boot instance %s at physical memory %pa of size 0x%lx\n",
10433 name, &start, (unsigned long)size);
10434 } else {
10435 pr_warn("Tracing: Failed to map boot instance %s\n", name);
10436 continue;
10437 }
10438 } else {
10439 /* Only non mapped buffers have snapshot buffers */
10440 if (IS_ENABLED(CONFIG_TRACER_MAX_TRACE))
10441 do_allocate_snapshot(name);
10442 }
10443
10444 tr = trace_array_create_systems(name, NULL, addr, size);
10445 if (IS_ERR(tr)) {
10446 pr_warn("Tracing: Failed to create instance buffer %s\n", curr_str);
10447 continue;
10448 }
10449
10450 if (traceoff)
10451 tracer_tracing_off(tr);
10452
10453 if (traceprintk)
10454 update_printk_trace(tr);
10455
10456 /*
10457 * If start is set, then this is a mapped buffer, and
10458 * cannot be deleted by user space, so keep the reference
10459 * to it.
10460 */
10461 if (start) {
10462 tr->flags |= TRACE_ARRAY_FL_BOOT;
10463 tr->ref++;
10464 }
10465
10466 while ((tok = strsep(&curr_str, ","))) {
10467 early_enable_events(tr, tok, true);
10468 }
10469 }
10470 }
10471
tracer_alloc_buffers(void)10472 __init static int tracer_alloc_buffers(void)
10473 {
10474 int ring_buf_size;
10475 int ret = -ENOMEM;
10476
10477
10478 if (security_locked_down(LOCKDOWN_TRACEFS)) {
10479 pr_warn("Tracing disabled due to lockdown\n");
10480 return -EPERM;
10481 }
10482
10483 /*
10484 * Make sure we don't accidentally add more trace options
10485 * than we have bits for.
10486 */
10487 BUILD_BUG_ON(TRACE_ITER_LAST_BIT > TRACE_FLAGS_MAX_SIZE);
10488
10489 if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
10490 goto out;
10491
10492 if (!alloc_cpumask_var(&global_trace.tracing_cpumask, GFP_KERNEL))
10493 goto out_free_buffer_mask;
10494
10495 /* Only allocate trace_printk buffers if a trace_printk exists */
10496 if (&__stop___trace_bprintk_fmt != &__start___trace_bprintk_fmt)
10497 /* Must be called before global_trace.buffer is allocated */
10498 trace_printk_init_buffers();
10499
10500 /* To save memory, keep the ring buffer size to its minimum */
10501 if (global_trace.ring_buffer_expanded)
10502 ring_buf_size = trace_buf_size;
10503 else
10504 ring_buf_size = 1;
10505
10506 cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
10507 cpumask_copy(global_trace.tracing_cpumask, cpu_all_mask);
10508
10509 raw_spin_lock_init(&global_trace.start_lock);
10510
10511 /*
10512 * The prepare callbacks allocates some memory for the ring buffer. We
10513 * don't free the buffer if the CPU goes down. If we were to free
10514 * the buffer, then the user would lose any trace that was in the
10515 * buffer. The memory will be removed once the "instance" is removed.
10516 */
10517 ret = cpuhp_setup_state_multi(CPUHP_TRACE_RB_PREPARE,
10518 "trace/RB:prepare", trace_rb_cpu_prepare,
10519 NULL);
10520 if (ret < 0)
10521 goto out_free_cpumask;
10522 /* Used for event triggers */
10523 ret = -ENOMEM;
10524 temp_buffer = ring_buffer_alloc(PAGE_SIZE, RB_FL_OVERWRITE);
10525 if (!temp_buffer)
10526 goto out_rm_hp_state;
10527
10528 if (trace_create_savedcmd() < 0)
10529 goto out_free_temp_buffer;
10530
10531 if (!zalloc_cpumask_var(&global_trace.pipe_cpumask, GFP_KERNEL))
10532 goto out_free_savedcmd;
10533
10534 /* TODO: make the number of buffers hot pluggable with CPUS */
10535 if (allocate_trace_buffers(&global_trace, ring_buf_size) < 0) {
10536 MEM_FAIL(1, "tracer: failed to allocate ring buffer!\n");
10537 goto out_free_pipe_cpumask;
10538 }
10539 if (global_trace.buffer_disabled)
10540 tracing_off();
10541
10542 if (trace_boot_clock) {
10543 ret = tracing_set_clock(&global_trace, trace_boot_clock);
10544 if (ret < 0)
10545 pr_warn("Trace clock %s not defined, going back to default\n",
10546 trace_boot_clock);
10547 }
10548
10549 /*
10550 * register_tracer() might reference current_trace, so it
10551 * needs to be set before we register anything. This is
10552 * just a bootstrap of current_trace anyway.
10553 */
10554 global_trace.current_trace = &nop_trace;
10555
10556 global_trace.max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
10557 #ifdef CONFIG_TRACER_MAX_TRACE
10558 spin_lock_init(&global_trace.snapshot_trigger_lock);
10559 #endif
10560 ftrace_init_global_array_ops(&global_trace);
10561
10562 #ifdef CONFIG_MODULES
10563 INIT_LIST_HEAD(&global_trace.mod_events);
10564 #endif
10565
10566 init_trace_flags_index(&global_trace);
10567
10568 register_tracer(&nop_trace);
10569
10570 /* Function tracing may start here (via kernel command line) */
10571 init_function_trace();
10572
10573 /* All seems OK, enable tracing */
10574 tracing_disabled = 0;
10575
10576 atomic_notifier_chain_register(&panic_notifier_list,
10577 &trace_panic_notifier);
10578
10579 register_die_notifier(&trace_die_notifier);
10580
10581 global_trace.flags = TRACE_ARRAY_FL_GLOBAL;
10582
10583 INIT_LIST_HEAD(&global_trace.systems);
10584 INIT_LIST_HEAD(&global_trace.events);
10585 INIT_LIST_HEAD(&global_trace.hist_vars);
10586 INIT_LIST_HEAD(&global_trace.err_log);
10587 list_add(&global_trace.list, &ftrace_trace_arrays);
10588
10589 apply_trace_boot_options();
10590
10591 register_snapshot_cmd();
10592
10593 return 0;
10594
10595 out_free_pipe_cpumask:
10596 free_cpumask_var(global_trace.pipe_cpumask);
10597 out_free_savedcmd:
10598 trace_free_saved_cmdlines_buffer();
10599 out_free_temp_buffer:
10600 ring_buffer_free(temp_buffer);
10601 out_rm_hp_state:
10602 cpuhp_remove_multi_state(CPUHP_TRACE_RB_PREPARE);
10603 out_free_cpumask:
10604 free_cpumask_var(global_trace.tracing_cpumask);
10605 out_free_buffer_mask:
10606 free_cpumask_var(tracing_buffer_mask);
10607 out:
10608 return ret;
10609 }
10610
10611 #ifdef CONFIG_FUNCTION_TRACER
10612 /* Used to set module cached ftrace filtering at boot up */
trace_get_global_array(void)10613 __init struct trace_array *trace_get_global_array(void)
10614 {
10615 return &global_trace;
10616 }
10617 #endif
10618
ftrace_boot_snapshot(void)10619 void __init ftrace_boot_snapshot(void)
10620 {
10621 #ifdef CONFIG_TRACER_MAX_TRACE
10622 struct trace_array *tr;
10623
10624 if (!snapshot_at_boot)
10625 return;
10626
10627 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
10628 if (!tr->allocated_snapshot)
10629 continue;
10630
10631 tracing_snapshot_instance(tr);
10632 trace_array_puts(tr, "** Boot snapshot taken **\n");
10633 }
10634 #endif
10635 }
10636
early_trace_init(void)10637 void __init early_trace_init(void)
10638 {
10639 if (tracepoint_printk) {
10640 tracepoint_print_iter =
10641 kzalloc(sizeof(*tracepoint_print_iter), GFP_KERNEL);
10642 if (MEM_FAIL(!tracepoint_print_iter,
10643 "Failed to allocate trace iterator\n"))
10644 tracepoint_printk = 0;
10645 else
10646 static_key_enable(&tracepoint_printk_key.key);
10647 }
10648 tracer_alloc_buffers();
10649
10650 init_events();
10651 }
10652
trace_init(void)10653 void __init trace_init(void)
10654 {
10655 trace_event_init();
10656
10657 if (boot_instance_index)
10658 enable_instances();
10659 }
10660
clear_boot_tracer(void)10661 __init static void clear_boot_tracer(void)
10662 {
10663 /*
10664 * The default tracer at boot buffer is an init section.
10665 * This function is called in lateinit. If we did not
10666 * find the boot tracer, then clear it out, to prevent
10667 * later registration from accessing the buffer that is
10668 * about to be freed.
10669 */
10670 if (!default_bootup_tracer)
10671 return;
10672
10673 printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n",
10674 default_bootup_tracer);
10675 default_bootup_tracer = NULL;
10676 }
10677
10678 #ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
tracing_set_default_clock(void)10679 __init static void tracing_set_default_clock(void)
10680 {
10681 /* sched_clock_stable() is determined in late_initcall */
10682 if (!trace_boot_clock && !sched_clock_stable()) {
10683 if (security_locked_down(LOCKDOWN_TRACEFS)) {
10684 pr_warn("Can not set tracing clock due to lockdown\n");
10685 return;
10686 }
10687
10688 printk(KERN_WARNING
10689 "Unstable clock detected, switching default tracing clock to \"global\"\n"
10690 "If you want to keep using the local clock, then add:\n"
10691 " \"trace_clock=local\"\n"
10692 "on the kernel command line\n");
10693 tracing_set_clock(&global_trace, "global");
10694 }
10695 }
10696 #else
tracing_set_default_clock(void)10697 static inline void tracing_set_default_clock(void) { }
10698 #endif
10699
late_trace_init(void)10700 __init static int late_trace_init(void)
10701 {
10702 if (tracepoint_printk && tracepoint_printk_stop_on_boot) {
10703 static_key_disable(&tracepoint_printk_key.key);
10704 tracepoint_printk = 0;
10705 }
10706
10707 tracing_set_default_clock();
10708 clear_boot_tracer();
10709 return 0;
10710 }
10711
10712 late_initcall_sync(late_trace_init);
10713