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1/* SPDX-License-Identifier: GPL-2.0-only */
2#ifndef _LINUX_TRACEPOINT_H
3#define _LINUX_TRACEPOINT_H
4
5/*
6 * Kernel Tracepoint API.
7 *
8 * See Documentation/trace/tracepoints.rst.
9 *
10 * Copyright (C) 2008-2014 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
11 *
12 * Heavily inspired from the Linux Kernel Markers.
13 */
14
15#include <linux/smp.h>
16#include <linux/srcu.h>
17#include <linux/errno.h>
18#include <linux/types.h>
19#include <linux/cpumask.h>
20#include <linux/rcupdate.h>
21#include <linux/tracepoint-defs.h>
22
23struct module;
24struct tracepoint;
25struct notifier_block;
26
27struct trace_eval_map {
28 const char *system;
29 const char *eval_string;
30 unsigned long eval_value;
31};
32
33#define TRACEPOINT_DEFAULT_PRIO 10
34
35extern struct srcu_struct tracepoint_srcu;
36
37extern int
38tracepoint_probe_register(struct tracepoint *tp, void *probe, void *data);
39extern int
40tracepoint_probe_register_prio(struct tracepoint *tp, void *probe, void *data,
41 int prio);
42extern int
43tracepoint_probe_unregister(struct tracepoint *tp, void *probe, void *data);
44extern void
45for_each_kernel_tracepoint(void (*fct)(struct tracepoint *tp, void *priv),
46 void *priv);
47
48#ifdef CONFIG_MODULES
49struct tp_module {
50 struct list_head list;
51 struct module *mod;
52};
53
54bool trace_module_has_bad_taint(struct module *mod);
55extern int register_tracepoint_module_notifier(struct notifier_block *nb);
56extern int unregister_tracepoint_module_notifier(struct notifier_block *nb);
57#else
58static inline bool trace_module_has_bad_taint(struct module *mod)
59{
60 return false;
61}
62static inline
63int register_tracepoint_module_notifier(struct notifier_block *nb)
64{
65 return 0;
66}
67static inline
68int unregister_tracepoint_module_notifier(struct notifier_block *nb)
69{
70 return 0;
71}
72#endif /* CONFIG_MODULES */
73
74/*
75 * tracepoint_synchronize_unregister must be called between the last tracepoint
76 * probe unregistration and the end of module exit to make sure there is no
77 * caller executing a probe when it is freed.
78 */
79#ifdef CONFIG_TRACEPOINTS
80static inline void tracepoint_synchronize_unregister(void)
81{
82 synchronize_srcu(&tracepoint_srcu);
83 synchronize_rcu();
84}
85#else
86static inline void tracepoint_synchronize_unregister(void)
87{ }
88#endif
89
90#ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
91extern int syscall_regfunc(void);
92extern void syscall_unregfunc(void);
93#endif /* CONFIG_HAVE_SYSCALL_TRACEPOINTS */
94
95#define PARAMS(args...) args
96
97#define TRACE_DEFINE_ENUM(x)
98#define TRACE_DEFINE_SIZEOF(x)
99
100#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
101static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
102{
103 return offset_to_ptr(p);
104}
105
106#define __TRACEPOINT_ENTRY(name) \
107 asm(" .section \"__tracepoints_ptrs\", \"a\" \n" \
108 " .balign 4 \n" \
109 " .long __tracepoint_" #name " - . \n" \
110 " .previous \n")
111#else
112static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
113{
114 return *p;
115}
116
117#define __TRACEPOINT_ENTRY(name) \
118 static tracepoint_ptr_t __tracepoint_ptr_##name __used \
119 __section(__tracepoints_ptrs) = &__tracepoint_##name
120#endif
121
122#endif /* _LINUX_TRACEPOINT_H */
123
124/*
125 * Note: we keep the TRACE_EVENT and DECLARE_TRACE outside the include
126 * file ifdef protection.
127 * This is due to the way trace events work. If a file includes two
128 * trace event headers under one "CREATE_TRACE_POINTS" the first include
129 * will override the TRACE_EVENT and break the second include.
130 */
131
132#ifndef DECLARE_TRACE
133
134#define TP_PROTO(args...) args
135#define TP_ARGS(args...) args
136#define TP_CONDITION(args...) args
137
138/*
139 * Individual subsystem my have a separate configuration to
140 * enable their tracepoints. By default, this file will create
141 * the tracepoints if CONFIG_TRACEPOINT is defined. If a subsystem
142 * wants to be able to disable its tracepoints from being created
143 * it can define NOTRACE before including the tracepoint headers.
144 */
145#if defined(CONFIG_TRACEPOINTS) && !defined(NOTRACE)
146#define TRACEPOINTS_ENABLED
147#endif
148
149#ifdef TRACEPOINTS_ENABLED
150
151/*
152 * it_func[0] is never NULL because there is at least one element in the array
153 * when the array itself is non NULL.
154 *
155 * Note, the proto and args passed in includes "__data" as the first parameter.
156 * The reason for this is to handle the "void" prototype. If a tracepoint
157 * has a "void" prototype, then it is invalid to declare a function
158 * as "(void *, void)".
159 */
160#define __DO_TRACE(tp, proto, args, cond, rcuidle) \
161 do { \
162 struct tracepoint_func *it_func_ptr; \
163 void *it_func; \
164 void *__data; \
165 int __maybe_unused __idx = 0; \
166 \
167 if (!(cond)) \
168 return; \
169 \
170 /* srcu can't be used from NMI */ \
171 WARN_ON_ONCE(rcuidle && in_nmi()); \
172 \
173 /* keep srcu and sched-rcu usage consistent */ \
174 preempt_disable_notrace(); \
175 \
176 /* \
177 * For rcuidle callers, use srcu since sched-rcu \
178 * doesn't work from the idle path. \
179 */ \
180 if (rcuidle) { \
181 __idx = srcu_read_lock_notrace(&tracepoint_srcu);\
182 rcu_irq_enter_irqson(); \
183 } \
184 \
185 it_func_ptr = rcu_dereference_raw((tp)->funcs); \
186 \
187 if (it_func_ptr) { \
188 do { \
189 it_func = (it_func_ptr)->func; \
190 __data = (it_func_ptr)->data; \
191 ((void(*)(proto))(it_func))(args); \
192 } while ((++it_func_ptr)->func); \
193 } \
194 \
195 if (rcuidle) { \
196 rcu_irq_exit_irqson(); \
197 srcu_read_unlock_notrace(&tracepoint_srcu, __idx);\
198 } \
199 \
200 preempt_enable_notrace(); \
201 } while (0)
202
203#ifndef MODULE
204#define __DECLARE_TRACE_RCU(name, proto, args, cond, data_proto, data_args) \
205 static inline void trace_##name##_rcuidle(proto) \
206 { \
207 if (static_key_false(&__tracepoint_##name.key)) \
208 __DO_TRACE(&__tracepoint_##name, \
209 TP_PROTO(data_proto), \
210 TP_ARGS(data_args), \
211 TP_CONDITION(cond), 1); \
212 }
213#else
214#define __DECLARE_TRACE_RCU(name, proto, args, cond, data_proto, data_args)
215#endif
216
217/*
218 * Make sure the alignment of the structure in the __tracepoints section will
219 * not add unwanted padding between the beginning of the section and the
220 * structure. Force alignment to the same alignment as the section start.
221 *
222 * When lockdep is enabled, we make sure to always do the RCU portions of
223 * the tracepoint code, regardless of whether tracing is on. However,
224 * don't check if the condition is false, due to interaction with idle
225 * instrumentation. This lets us find RCU issues triggered with tracepoints
226 * even when this tracepoint is off. This code has no purpose other than
227 * poking RCU a bit.
228 */
229#define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args) \
230 extern struct tracepoint __tracepoint_##name; \
231 static inline void trace_##name(proto) \
232 { \
233 if (static_key_false(&__tracepoint_##name.key)) \
234 __DO_TRACE(&__tracepoint_##name, \
235 TP_PROTO(data_proto), \
236 TP_ARGS(data_args), \
237 TP_CONDITION(cond), 0); \
238 if (IS_ENABLED(CONFIG_LOCKDEP) && (cond)) { \
239 rcu_read_lock_sched_notrace(); \
240 rcu_dereference_sched(__tracepoint_##name.funcs);\
241 rcu_read_unlock_sched_notrace(); \
242 } \
243 } \
244 __DECLARE_TRACE_RCU(name, PARAMS(proto), PARAMS(args), \
245 PARAMS(cond), PARAMS(data_proto), PARAMS(data_args)) \
246 static inline int \
247 register_trace_##name(void (*probe)(data_proto), void *data) \
248 { \
249 return tracepoint_probe_register(&__tracepoint_##name, \
250 (void *)probe, data); \
251 } \
252 static inline int \
253 register_trace_prio_##name(void (*probe)(data_proto), void *data,\
254 int prio) \
255 { \
256 return tracepoint_probe_register_prio(&__tracepoint_##name, \
257 (void *)probe, data, prio); \
258 } \
259 static inline int \
260 unregister_trace_##name(void (*probe)(data_proto), void *data) \
261 { \
262 return tracepoint_probe_unregister(&__tracepoint_##name,\
263 (void *)probe, data); \
264 } \
265 static inline void \
266 check_trace_callback_type_##name(void (*cb)(data_proto)) \
267 { \
268 } \
269 static inline bool \
270 trace_##name##_enabled(void) \
271 { \
272 return static_key_false(&__tracepoint_##name.key); \
273 }
274
275/*
276 * We have no guarantee that gcc and the linker won't up-align the tracepoint
277 * structures, so we create an array of pointers that will be used for iteration
278 * on the tracepoints.
279 */
280#define DEFINE_TRACE_FN(name, reg, unreg) \
281 static const char __tpstrtab_##name[] \
282 __section(__tracepoints_strings) = #name; \
283 struct tracepoint __tracepoint_##name __used \
284 __section(__tracepoints) = \
285 { __tpstrtab_##name, STATIC_KEY_INIT_FALSE, reg, unreg, NULL };\
286 __TRACEPOINT_ENTRY(name);
287
288#define DEFINE_TRACE(name) \
289 DEFINE_TRACE_FN(name, NULL, NULL);
290
291#define EXPORT_TRACEPOINT_SYMBOL_GPL(name) \
292 EXPORT_SYMBOL_GPL(__tracepoint_##name)
293#define EXPORT_TRACEPOINT_SYMBOL(name) \
294 EXPORT_SYMBOL(__tracepoint_##name)
295
296#else /* !TRACEPOINTS_ENABLED */
297#define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args) \
298 static inline void trace_##name(proto) \
299 { } \
300 static inline void trace_##name##_rcuidle(proto) \
301 { } \
302 static inline int \
303 register_trace_##name(void (*probe)(data_proto), \
304 void *data) \
305 { \
306 return -ENOSYS; \
307 } \
308 static inline int \
309 unregister_trace_##name(void (*probe)(data_proto), \
310 void *data) \
311 { \
312 return -ENOSYS; \
313 } \
314 static inline void check_trace_callback_type_##name(void (*cb)(data_proto)) \
315 { \
316 } \
317 static inline bool \
318 trace_##name##_enabled(void) \
319 { \
320 return false; \
321 }
322
323#define DEFINE_TRACE_FN(name, reg, unreg)
324#define DEFINE_TRACE(name)
325#define EXPORT_TRACEPOINT_SYMBOL_GPL(name)
326#define EXPORT_TRACEPOINT_SYMBOL(name)
327
328#endif /* TRACEPOINTS_ENABLED */
329
330#ifdef CONFIG_TRACING
331/**
332 * tracepoint_string - register constant persistent string to trace system
333 * @str - a constant persistent string that will be referenced in tracepoints
334 *
335 * If constant strings are being used in tracepoints, it is faster and
336 * more efficient to just save the pointer to the string and reference
337 * that with a printf "%s" instead of saving the string in the ring buffer
338 * and wasting space and time.
339 *
340 * The problem with the above approach is that userspace tools that read
341 * the binary output of the trace buffers do not have access to the string.
342 * Instead they just show the address of the string which is not very
343 * useful to users.
344 *
345 * With tracepoint_string(), the string will be registered to the tracing
346 * system and exported to userspace via the debugfs/tracing/printk_formats
347 * file that maps the string address to the string text. This way userspace
348 * tools that read the binary buffers have a way to map the pointers to
349 * the ASCII strings they represent.
350 *
351 * The @str used must be a constant string and persistent as it would not
352 * make sense to show a string that no longer exists. But it is still fine
353 * to be used with modules, because when modules are unloaded, if they
354 * had tracepoints, the ring buffers are cleared too. As long as the string
355 * does not change during the life of the module, it is fine to use
356 * tracepoint_string() within a module.
357 */
358#define tracepoint_string(str) \
359 ({ \
360 static const char *___tp_str __tracepoint_string = str; \
361 ___tp_str; \
362 })
363#define __tracepoint_string __used __section(__tracepoint_str)
364#else
365/*
366 * tracepoint_string() is used to save the string address for userspace
367 * tracing tools. When tracing isn't configured, there's no need to save
368 * anything.
369 */
370# define tracepoint_string(str) str
371# define __tracepoint_string
372#endif
373
374#define DECLARE_TRACE(name, proto, args) \
375 __DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), \
376 cpu_online(raw_smp_processor_id()), \
377 PARAMS(void *__data, proto), \
378 PARAMS(__data, args))
379
380#define DECLARE_TRACE_CONDITION(name, proto, args, cond) \
381 __DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), \
382 cpu_online(raw_smp_processor_id()) && (PARAMS(cond)), \
383 PARAMS(void *__data, proto), \
384 PARAMS(__data, args))
385
386#define TRACE_EVENT_FLAGS(event, flag)
387
388#define TRACE_EVENT_PERF_PERM(event, expr...)
389
390#endif /* DECLARE_TRACE */
391
392#ifndef TRACE_EVENT
393/*
394 * For use with the TRACE_EVENT macro:
395 *
396 * We define a tracepoint, its arguments, its printk format
397 * and its 'fast binary record' layout.
398 *
399 * Firstly, name your tracepoint via TRACE_EVENT(name : the
400 * 'subsystem_event' notation is fine.
401 *
402 * Think about this whole construct as the
403 * 'trace_sched_switch() function' from now on.
404 *
405 *
406 * TRACE_EVENT(sched_switch,
407 *
408 * *
409 * * A function has a regular function arguments
410 * * prototype, declare it via TP_PROTO():
411 * *
412 *
413 * TP_PROTO(struct rq *rq, struct task_struct *prev,
414 * struct task_struct *next),
415 *
416 * *
417 * * Define the call signature of the 'function'.
418 * * (Design sidenote: we use this instead of a
419 * * TP_PROTO1/TP_PROTO2/TP_PROTO3 ugliness.)
420 * *
421 *
422 * TP_ARGS(rq, prev, next),
423 *
424 * *
425 * * Fast binary tracing: define the trace record via
426 * * TP_STRUCT__entry(). You can think about it like a
427 * * regular C structure local variable definition.
428 * *
429 * * This is how the trace record is structured and will
430 * * be saved into the ring buffer. These are the fields
431 * * that will be exposed to user-space in
432 * * /sys/kernel/debug/tracing/events/<*>/format.
433 * *
434 * * The declared 'local variable' is called '__entry'
435 * *
436 * * __field(pid_t, prev_prid) is equivalent to a standard declariton:
437 * *
438 * * pid_t prev_pid;
439 * *
440 * * __array(char, prev_comm, TASK_COMM_LEN) is equivalent to:
441 * *
442 * * char prev_comm[TASK_COMM_LEN];
443 * *
444 *
445 * TP_STRUCT__entry(
446 * __array( char, prev_comm, TASK_COMM_LEN )
447 * __field( pid_t, prev_pid )
448 * __field( int, prev_prio )
449 * __array( char, next_comm, TASK_COMM_LEN )
450 * __field( pid_t, next_pid )
451 * __field( int, next_prio )
452 * ),
453 *
454 * *
455 * * Assign the entry into the trace record, by embedding
456 * * a full C statement block into TP_fast_assign(). You
457 * * can refer to the trace record as '__entry' -
458 * * otherwise you can put arbitrary C code in here.
459 * *
460 * * Note: this C code will execute every time a trace event
461 * * happens, on an active tracepoint.
462 * *
463 *
464 * TP_fast_assign(
465 * memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN);
466 * __entry->prev_pid = prev->pid;
467 * __entry->prev_prio = prev->prio;
468 * memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN);
469 * __entry->next_pid = next->pid;
470 * __entry->next_prio = next->prio;
471 * ),
472 *
473 * *
474 * * Formatted output of a trace record via TP_printk().
475 * * This is how the tracepoint will appear under ftrace
476 * * plugins that make use of this tracepoint.
477 * *
478 * * (raw-binary tracing wont actually perform this step.)
479 * *
480 *
481 * TP_printk("task %s:%d [%d] ==> %s:%d [%d]",
482 * __entry->prev_comm, __entry->prev_pid, __entry->prev_prio,
483 * __entry->next_comm, __entry->next_pid, __entry->next_prio),
484 *
485 * );
486 *
487 * This macro construct is thus used for the regular printk format
488 * tracing setup, it is used to construct a function pointer based
489 * tracepoint callback (this is used by programmatic plugins and
490 * can also by used by generic instrumentation like SystemTap), and
491 * it is also used to expose a structured trace record in
492 * /sys/kernel/debug/tracing/events/.
493 *
494 * A set of (un)registration functions can be passed to the variant
495 * TRACE_EVENT_FN to perform any (un)registration work.
496 */
497
498#define DECLARE_EVENT_CLASS(name, proto, args, tstruct, assign, print)
499#define DEFINE_EVENT(template, name, proto, args) \
500 DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
501#define DEFINE_EVENT_FN(template, name, proto, args, reg, unreg)\
502 DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
503#define DEFINE_EVENT_PRINT(template, name, proto, args, print) \
504 DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
505#define DEFINE_EVENT_CONDITION(template, name, proto, \
506 args, cond) \
507 DECLARE_TRACE_CONDITION(name, PARAMS(proto), \
508 PARAMS(args), PARAMS(cond))
509
510#define TRACE_EVENT(name, proto, args, struct, assign, print) \
511 DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
512#define TRACE_EVENT_FN(name, proto, args, struct, \
513 assign, print, reg, unreg) \
514 DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
515#define TRACE_EVENT_FN_COND(name, proto, args, cond, struct, \
516 assign, print, reg, unreg) \
517 DECLARE_TRACE_CONDITION(name, PARAMS(proto), \
518 PARAMS(args), PARAMS(cond))
519#define TRACE_EVENT_CONDITION(name, proto, args, cond, \
520 struct, assign, print) \
521 DECLARE_TRACE_CONDITION(name, PARAMS(proto), \
522 PARAMS(args), PARAMS(cond))
523
524#define TRACE_EVENT_FLAGS(event, flag)
525
526#define TRACE_EVENT_PERF_PERM(event, expr...)
527
528#define DECLARE_EVENT_NOP(name, proto, args) \
529 static inline void trace_##name(proto) \
530 { } \
531 static inline bool trace_##name##_enabled(void) \
532 { \
533 return false; \
534 }
535
536#define TRACE_EVENT_NOP(name, proto, args, struct, assign, print) \
537 DECLARE_EVENT_NOP(name, PARAMS(proto), PARAMS(args))
538
539#define DECLARE_EVENT_CLASS_NOP(name, proto, args, tstruct, assign, print)
540#define DEFINE_EVENT_NOP(template, name, proto, args) \
541 DECLARE_EVENT_NOP(name, PARAMS(proto), PARAMS(args))
542
543#endif /* ifdef TRACE_EVENT (see note above) */
1#ifndef _LINUX_TRACEPOINT_H
2#define _LINUX_TRACEPOINT_H
3
4/*
5 * Kernel Tracepoint API.
6 *
7 * See Documentation/trace/tracepoints.txt.
8 *
9 * Copyright (C) 2008-2014 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
10 *
11 * Heavily inspired from the Linux Kernel Markers.
12 *
13 * This file is released under the GPLv2.
14 * See the file COPYING for more details.
15 */
16
17#include <linux/smp.h>
18#include <linux/errno.h>
19#include <linux/types.h>
20#include <linux/cpumask.h>
21#include <linux/rcupdate.h>
22#include <linux/tracepoint-defs.h>
23
24struct module;
25struct tracepoint;
26struct notifier_block;
27
28struct trace_enum_map {
29 const char *system;
30 const char *enum_string;
31 unsigned long enum_value;
32};
33
34#define TRACEPOINT_DEFAULT_PRIO 10
35
36extern int
37tracepoint_probe_register(struct tracepoint *tp, void *probe, void *data);
38extern int
39tracepoint_probe_register_prio(struct tracepoint *tp, void *probe, void *data,
40 int prio);
41extern int
42tracepoint_probe_unregister(struct tracepoint *tp, void *probe, void *data);
43extern void
44for_each_kernel_tracepoint(void (*fct)(struct tracepoint *tp, void *priv),
45 void *priv);
46
47#ifdef CONFIG_MODULES
48struct tp_module {
49 struct list_head list;
50 struct module *mod;
51};
52
53bool trace_module_has_bad_taint(struct module *mod);
54extern int register_tracepoint_module_notifier(struct notifier_block *nb);
55extern int unregister_tracepoint_module_notifier(struct notifier_block *nb);
56#else
57static inline bool trace_module_has_bad_taint(struct module *mod)
58{
59 return false;
60}
61static inline
62int register_tracepoint_module_notifier(struct notifier_block *nb)
63{
64 return 0;
65}
66static inline
67int unregister_tracepoint_module_notifier(struct notifier_block *nb)
68{
69 return 0;
70}
71#endif /* CONFIG_MODULES */
72
73/*
74 * tracepoint_synchronize_unregister must be called between the last tracepoint
75 * probe unregistration and the end of module exit to make sure there is no
76 * caller executing a probe when it is freed.
77 */
78static inline void tracepoint_synchronize_unregister(void)
79{
80 synchronize_sched();
81}
82
83#ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
84extern int syscall_regfunc(void);
85extern void syscall_unregfunc(void);
86#endif /* CONFIG_HAVE_SYSCALL_TRACEPOINTS */
87
88#define PARAMS(args...) args
89
90#define TRACE_DEFINE_ENUM(x)
91
92#endif /* _LINUX_TRACEPOINT_H */
93
94/*
95 * Note: we keep the TRACE_EVENT and DECLARE_TRACE outside the include
96 * file ifdef protection.
97 * This is due to the way trace events work. If a file includes two
98 * trace event headers under one "CREATE_TRACE_POINTS" the first include
99 * will override the TRACE_EVENT and break the second include.
100 */
101
102#ifndef DECLARE_TRACE
103
104#define TP_PROTO(args...) args
105#define TP_ARGS(args...) args
106#define TP_CONDITION(args...) args
107
108/*
109 * Individual subsystem my have a separate configuration to
110 * enable their tracepoints. By default, this file will create
111 * the tracepoints if CONFIG_TRACEPOINT is defined. If a subsystem
112 * wants to be able to disable its tracepoints from being created
113 * it can define NOTRACE before including the tracepoint headers.
114 */
115#if defined(CONFIG_TRACEPOINTS) && !defined(NOTRACE)
116#define TRACEPOINTS_ENABLED
117#endif
118
119#ifdef TRACEPOINTS_ENABLED
120
121/*
122 * it_func[0] is never NULL because there is at least one element in the array
123 * when the array itself is non NULL.
124 *
125 * Note, the proto and args passed in includes "__data" as the first parameter.
126 * The reason for this is to handle the "void" prototype. If a tracepoint
127 * has a "void" prototype, then it is invalid to declare a function
128 * as "(void *, void)". The DECLARE_TRACE_NOARGS() will pass in just
129 * "void *data", where as the DECLARE_TRACE() will pass in "void *data, proto".
130 */
131#define __DO_TRACE(tp, proto, args, cond, prercu, postrcu) \
132 do { \
133 struct tracepoint_func *it_func_ptr; \
134 void *it_func; \
135 void *__data; \
136 \
137 if (!(cond)) \
138 return; \
139 prercu; \
140 rcu_read_lock_sched_notrace(); \
141 it_func_ptr = rcu_dereference_sched((tp)->funcs); \
142 if (it_func_ptr) { \
143 do { \
144 it_func = (it_func_ptr)->func; \
145 __data = (it_func_ptr)->data; \
146 ((void(*)(proto))(it_func))(args); \
147 } while ((++it_func_ptr)->func); \
148 } \
149 rcu_read_unlock_sched_notrace(); \
150 postrcu; \
151 } while (0)
152
153#ifndef MODULE
154#define __DECLARE_TRACE_RCU(name, proto, args, cond, data_proto, data_args) \
155 static inline void trace_##name##_rcuidle(proto) \
156 { \
157 if (static_key_false(&__tracepoint_##name.key)) \
158 __DO_TRACE(&__tracepoint_##name, \
159 TP_PROTO(data_proto), \
160 TP_ARGS(data_args), \
161 TP_CONDITION(cond), \
162 rcu_irq_enter_irqson(), \
163 rcu_irq_exit_irqson()); \
164 }
165#else
166#define __DECLARE_TRACE_RCU(name, proto, args, cond, data_proto, data_args)
167#endif
168
169/*
170 * Make sure the alignment of the structure in the __tracepoints section will
171 * not add unwanted padding between the beginning of the section and the
172 * structure. Force alignment to the same alignment as the section start.
173 *
174 * When lockdep is enabled, we make sure to always do the RCU portions of
175 * the tracepoint code, regardless of whether tracing is on. However,
176 * don't check if the condition is false, due to interaction with idle
177 * instrumentation. This lets us find RCU issues triggered with tracepoints
178 * even when this tracepoint is off. This code has no purpose other than
179 * poking RCU a bit.
180 */
181#define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args) \
182 extern struct tracepoint __tracepoint_##name; \
183 static inline void trace_##name(proto) \
184 { \
185 if (static_key_false(&__tracepoint_##name.key)) \
186 __DO_TRACE(&__tracepoint_##name, \
187 TP_PROTO(data_proto), \
188 TP_ARGS(data_args), \
189 TP_CONDITION(cond),,); \
190 if (IS_ENABLED(CONFIG_LOCKDEP) && (cond)) { \
191 rcu_read_lock_sched_notrace(); \
192 rcu_dereference_sched(__tracepoint_##name.funcs);\
193 rcu_read_unlock_sched_notrace(); \
194 } \
195 } \
196 __DECLARE_TRACE_RCU(name, PARAMS(proto), PARAMS(args), \
197 PARAMS(cond), PARAMS(data_proto), PARAMS(data_args)) \
198 static inline int \
199 register_trace_##name(void (*probe)(data_proto), void *data) \
200 { \
201 return tracepoint_probe_register(&__tracepoint_##name, \
202 (void *)probe, data); \
203 } \
204 static inline int \
205 register_trace_prio_##name(void (*probe)(data_proto), void *data,\
206 int prio) \
207 { \
208 return tracepoint_probe_register_prio(&__tracepoint_##name, \
209 (void *)probe, data, prio); \
210 } \
211 static inline int \
212 unregister_trace_##name(void (*probe)(data_proto), void *data) \
213 { \
214 return tracepoint_probe_unregister(&__tracepoint_##name,\
215 (void *)probe, data); \
216 } \
217 static inline void \
218 check_trace_callback_type_##name(void (*cb)(data_proto)) \
219 { \
220 } \
221 static inline bool \
222 trace_##name##_enabled(void) \
223 { \
224 return static_key_false(&__tracepoint_##name.key); \
225 }
226
227/*
228 * We have no guarantee that gcc and the linker won't up-align the tracepoint
229 * structures, so we create an array of pointers that will be used for iteration
230 * on the tracepoints.
231 */
232#define DEFINE_TRACE_FN(name, reg, unreg) \
233 static const char __tpstrtab_##name[] \
234 __attribute__((section("__tracepoints_strings"))) = #name; \
235 struct tracepoint __tracepoint_##name \
236 __attribute__((section("__tracepoints"))) = \
237 { __tpstrtab_##name, STATIC_KEY_INIT_FALSE, reg, unreg, NULL };\
238 static struct tracepoint * const __tracepoint_ptr_##name __used \
239 __attribute__((section("__tracepoints_ptrs"))) = \
240 &__tracepoint_##name;
241
242#define DEFINE_TRACE(name) \
243 DEFINE_TRACE_FN(name, NULL, NULL);
244
245#define EXPORT_TRACEPOINT_SYMBOL_GPL(name) \
246 EXPORT_SYMBOL_GPL(__tracepoint_##name)
247#define EXPORT_TRACEPOINT_SYMBOL(name) \
248 EXPORT_SYMBOL(__tracepoint_##name)
249
250#else /* !TRACEPOINTS_ENABLED */
251#define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args) \
252 static inline void trace_##name(proto) \
253 { } \
254 static inline void trace_##name##_rcuidle(proto) \
255 { } \
256 static inline int \
257 register_trace_##name(void (*probe)(data_proto), \
258 void *data) \
259 { \
260 return -ENOSYS; \
261 } \
262 static inline int \
263 unregister_trace_##name(void (*probe)(data_proto), \
264 void *data) \
265 { \
266 return -ENOSYS; \
267 } \
268 static inline void check_trace_callback_type_##name(void (*cb)(data_proto)) \
269 { \
270 } \
271 static inline bool \
272 trace_##name##_enabled(void) \
273 { \
274 return false; \
275 }
276
277#define DEFINE_TRACE_FN(name, reg, unreg)
278#define DEFINE_TRACE(name)
279#define EXPORT_TRACEPOINT_SYMBOL_GPL(name)
280#define EXPORT_TRACEPOINT_SYMBOL(name)
281
282#endif /* TRACEPOINTS_ENABLED */
283
284#ifdef CONFIG_TRACING
285/**
286 * tracepoint_string - register constant persistent string to trace system
287 * @str - a constant persistent string that will be referenced in tracepoints
288 *
289 * If constant strings are being used in tracepoints, it is faster and
290 * more efficient to just save the pointer to the string and reference
291 * that with a printf "%s" instead of saving the string in the ring buffer
292 * and wasting space and time.
293 *
294 * The problem with the above approach is that userspace tools that read
295 * the binary output of the trace buffers do not have access to the string.
296 * Instead they just show the address of the string which is not very
297 * useful to users.
298 *
299 * With tracepoint_string(), the string will be registered to the tracing
300 * system and exported to userspace via the debugfs/tracing/printk_formats
301 * file that maps the string address to the string text. This way userspace
302 * tools that read the binary buffers have a way to map the pointers to
303 * the ASCII strings they represent.
304 *
305 * The @str used must be a constant string and persistent as it would not
306 * make sense to show a string that no longer exists. But it is still fine
307 * to be used with modules, because when modules are unloaded, if they
308 * had tracepoints, the ring buffers are cleared too. As long as the string
309 * does not change during the life of the module, it is fine to use
310 * tracepoint_string() within a module.
311 */
312#define tracepoint_string(str) \
313 ({ \
314 static const char *___tp_str __tracepoint_string = str; \
315 ___tp_str; \
316 })
317#define __tracepoint_string __attribute__((section("__tracepoint_str")))
318#else
319/*
320 * tracepoint_string() is used to save the string address for userspace
321 * tracing tools. When tracing isn't configured, there's no need to save
322 * anything.
323 */
324# define tracepoint_string(str) str
325# define __tracepoint_string
326#endif
327
328/*
329 * The need for the DECLARE_TRACE_NOARGS() is to handle the prototype
330 * (void). "void" is a special value in a function prototype and can
331 * not be combined with other arguments. Since the DECLARE_TRACE()
332 * macro adds a data element at the beginning of the prototype,
333 * we need a way to differentiate "(void *data, proto)" from
334 * "(void *data, void)". The second prototype is invalid.
335 *
336 * DECLARE_TRACE_NOARGS() passes "void" as the tracepoint prototype
337 * and "void *__data" as the callback prototype.
338 *
339 * DECLARE_TRACE() passes "proto" as the tracepoint protoype and
340 * "void *__data, proto" as the callback prototype.
341 */
342#define DECLARE_TRACE_NOARGS(name) \
343 __DECLARE_TRACE(name, void, , \
344 cpu_online(raw_smp_processor_id()), \
345 void *__data, __data)
346
347#define DECLARE_TRACE(name, proto, args) \
348 __DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), \
349 cpu_online(raw_smp_processor_id()), \
350 PARAMS(void *__data, proto), \
351 PARAMS(__data, args))
352
353#define DECLARE_TRACE_CONDITION(name, proto, args, cond) \
354 __DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), \
355 cpu_online(raw_smp_processor_id()) && (PARAMS(cond)), \
356 PARAMS(void *__data, proto), \
357 PARAMS(__data, args))
358
359#define TRACE_EVENT_FLAGS(event, flag)
360
361#define TRACE_EVENT_PERF_PERM(event, expr...)
362
363#endif /* DECLARE_TRACE */
364
365#ifndef TRACE_EVENT
366/*
367 * For use with the TRACE_EVENT macro:
368 *
369 * We define a tracepoint, its arguments, its printk format
370 * and its 'fast binary record' layout.
371 *
372 * Firstly, name your tracepoint via TRACE_EVENT(name : the
373 * 'subsystem_event' notation is fine.
374 *
375 * Think about this whole construct as the
376 * 'trace_sched_switch() function' from now on.
377 *
378 *
379 * TRACE_EVENT(sched_switch,
380 *
381 * *
382 * * A function has a regular function arguments
383 * * prototype, declare it via TP_PROTO():
384 * *
385 *
386 * TP_PROTO(struct rq *rq, struct task_struct *prev,
387 * struct task_struct *next),
388 *
389 * *
390 * * Define the call signature of the 'function'.
391 * * (Design sidenote: we use this instead of a
392 * * TP_PROTO1/TP_PROTO2/TP_PROTO3 ugliness.)
393 * *
394 *
395 * TP_ARGS(rq, prev, next),
396 *
397 * *
398 * * Fast binary tracing: define the trace record via
399 * * TP_STRUCT__entry(). You can think about it like a
400 * * regular C structure local variable definition.
401 * *
402 * * This is how the trace record is structured and will
403 * * be saved into the ring buffer. These are the fields
404 * * that will be exposed to user-space in
405 * * /sys/kernel/debug/tracing/events/<*>/format.
406 * *
407 * * The declared 'local variable' is called '__entry'
408 * *
409 * * __field(pid_t, prev_prid) is equivalent to a standard declariton:
410 * *
411 * * pid_t prev_pid;
412 * *
413 * * __array(char, prev_comm, TASK_COMM_LEN) is equivalent to:
414 * *
415 * * char prev_comm[TASK_COMM_LEN];
416 * *
417 *
418 * TP_STRUCT__entry(
419 * __array( char, prev_comm, TASK_COMM_LEN )
420 * __field( pid_t, prev_pid )
421 * __field( int, prev_prio )
422 * __array( char, next_comm, TASK_COMM_LEN )
423 * __field( pid_t, next_pid )
424 * __field( int, next_prio )
425 * ),
426 *
427 * *
428 * * Assign the entry into the trace record, by embedding
429 * * a full C statement block into TP_fast_assign(). You
430 * * can refer to the trace record as '__entry' -
431 * * otherwise you can put arbitrary C code in here.
432 * *
433 * * Note: this C code will execute every time a trace event
434 * * happens, on an active tracepoint.
435 * *
436 *
437 * TP_fast_assign(
438 * memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN);
439 * __entry->prev_pid = prev->pid;
440 * __entry->prev_prio = prev->prio;
441 * memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN);
442 * __entry->next_pid = next->pid;
443 * __entry->next_prio = next->prio;
444 * ),
445 *
446 * *
447 * * Formatted output of a trace record via TP_printk().
448 * * This is how the tracepoint will appear under ftrace
449 * * plugins that make use of this tracepoint.
450 * *
451 * * (raw-binary tracing wont actually perform this step.)
452 * *
453 *
454 * TP_printk("task %s:%d [%d] ==> %s:%d [%d]",
455 * __entry->prev_comm, __entry->prev_pid, __entry->prev_prio,
456 * __entry->next_comm, __entry->next_pid, __entry->next_prio),
457 *
458 * );
459 *
460 * This macro construct is thus used for the regular printk format
461 * tracing setup, it is used to construct a function pointer based
462 * tracepoint callback (this is used by programmatic plugins and
463 * can also by used by generic instrumentation like SystemTap), and
464 * it is also used to expose a structured trace record in
465 * /sys/kernel/debug/tracing/events/.
466 *
467 * A set of (un)registration functions can be passed to the variant
468 * TRACE_EVENT_FN to perform any (un)registration work.
469 */
470
471#define DECLARE_EVENT_CLASS(name, proto, args, tstruct, assign, print)
472#define DEFINE_EVENT(template, name, proto, args) \
473 DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
474#define DEFINE_EVENT_FN(template, name, proto, args, reg, unreg)\
475 DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
476#define DEFINE_EVENT_PRINT(template, name, proto, args, print) \
477 DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
478#define DEFINE_EVENT_CONDITION(template, name, proto, \
479 args, cond) \
480 DECLARE_TRACE_CONDITION(name, PARAMS(proto), \
481 PARAMS(args), PARAMS(cond))
482
483#define TRACE_EVENT(name, proto, args, struct, assign, print) \
484 DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
485#define TRACE_EVENT_FN(name, proto, args, struct, \
486 assign, print, reg, unreg) \
487 DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
488#define TRACE_EVENT_FN_COND(name, proto, args, cond, struct, \
489 assign, print, reg, unreg) \
490 DECLARE_TRACE_CONDITION(name, PARAMS(proto), \
491 PARAMS(args), PARAMS(cond))
492#define TRACE_EVENT_CONDITION(name, proto, args, cond, \
493 struct, assign, print) \
494 DECLARE_TRACE_CONDITION(name, PARAMS(proto), \
495 PARAMS(args), PARAMS(cond))
496
497#define TRACE_EVENT_FLAGS(event, flag)
498
499#define TRACE_EVENT_PERF_PERM(event, expr...)
500
501#endif /* ifdef TRACE_EVENT (see note above) */