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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_eval_map {
29 const char *system;
30 const char *eval_string;
31 unsigned long eval_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#define TRACE_DEFINE_SIZEOF(x)
92
93#endif /* _LINUX_TRACEPOINT_H */
94
95/*
96 * Note: we keep the TRACE_EVENT and DECLARE_TRACE outside the include
97 * file ifdef protection.
98 * This is due to the way trace events work. If a file includes two
99 * trace event headers under one "CREATE_TRACE_POINTS" the first include
100 * will override the TRACE_EVENT and break the second include.
101 */
102
103#ifndef DECLARE_TRACE
104
105#define TP_PROTO(args...) args
106#define TP_ARGS(args...) args
107#define TP_CONDITION(args...) args
108
109/*
110 * Individual subsystem my have a separate configuration to
111 * enable their tracepoints. By default, this file will create
112 * the tracepoints if CONFIG_TRACEPOINT is defined. If a subsystem
113 * wants to be able to disable its tracepoints from being created
114 * it can define NOTRACE before including the tracepoint headers.
115 */
116#if defined(CONFIG_TRACEPOINTS) && !defined(NOTRACE)
117#define TRACEPOINTS_ENABLED
118#endif
119
120#ifdef TRACEPOINTS_ENABLED
121
122/*
123 * it_func[0] is never NULL because there is at least one element in the array
124 * when the array itself is non NULL.
125 *
126 * Note, the proto and args passed in includes "__data" as the first parameter.
127 * The reason for this is to handle the "void" prototype. If a tracepoint
128 * has a "void" prototype, then it is invalid to declare a function
129 * as "(void *, void)". The DECLARE_TRACE_NOARGS() will pass in just
130 * "void *data", where as the DECLARE_TRACE() will pass in "void *data, proto".
131 */
132#define __DO_TRACE(tp, proto, args, cond, rcucheck) \
133 do { \
134 struct tracepoint_func *it_func_ptr; \
135 void *it_func; \
136 void *__data; \
137 \
138 if (!(cond)) \
139 return; \
140 if (rcucheck) \
141 rcu_irq_enter_irqson(); \
142 rcu_read_lock_sched_notrace(); \
143 it_func_ptr = rcu_dereference_sched((tp)->funcs); \
144 if (it_func_ptr) { \
145 do { \
146 it_func = (it_func_ptr)->func; \
147 __data = (it_func_ptr)->data; \
148 ((void(*)(proto))(it_func))(args); \
149 } while ((++it_func_ptr)->func); \
150 } \
151 rcu_read_unlock_sched_notrace(); \
152 if (rcucheck) \
153 rcu_irq_exit_irqson(); \
154 } while (0)
155
156#ifndef MODULE
157#define __DECLARE_TRACE_RCU(name, proto, args, cond, data_proto, data_args) \
158 static inline void trace_##name##_rcuidle(proto) \
159 { \
160 if (static_key_false(&__tracepoint_##name.key)) \
161 __DO_TRACE(&__tracepoint_##name, \
162 TP_PROTO(data_proto), \
163 TP_ARGS(data_args), \
164 TP_CONDITION(cond), 1); \
165 }
166#else
167#define __DECLARE_TRACE_RCU(name, proto, args, cond, data_proto, data_args)
168#endif
169
170/*
171 * Make sure the alignment of the structure in the __tracepoints section will
172 * not add unwanted padding between the beginning of the section and the
173 * structure. Force alignment to the same alignment as the section start.
174 *
175 * When lockdep is enabled, we make sure to always do the RCU portions of
176 * the tracepoint code, regardless of whether tracing is on. However,
177 * don't check if the condition is false, due to interaction with idle
178 * instrumentation. This lets us find RCU issues triggered with tracepoints
179 * even when this tracepoint is off. This code has no purpose other than
180 * poking RCU a bit.
181 */
182#define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args) \
183 extern struct tracepoint __tracepoint_##name; \
184 static inline void trace_##name(proto) \
185 { \
186 if (static_key_false(&__tracepoint_##name.key)) \
187 __DO_TRACE(&__tracepoint_##name, \
188 TP_PROTO(data_proto), \
189 TP_ARGS(data_args), \
190 TP_CONDITION(cond), 0); \
191 if (IS_ENABLED(CONFIG_LOCKDEP) && (cond)) { \
192 rcu_read_lock_sched_notrace(); \
193 rcu_dereference_sched(__tracepoint_##name.funcs);\
194 rcu_read_unlock_sched_notrace(); \
195 } \
196 } \
197 __DECLARE_TRACE_RCU(name, PARAMS(proto), PARAMS(args), \
198 PARAMS(cond), PARAMS(data_proto), PARAMS(data_args)) \
199 static inline int \
200 register_trace_##name(void (*probe)(data_proto), void *data) \
201 { \
202 return tracepoint_probe_register(&__tracepoint_##name, \
203 (void *)probe, data); \
204 } \
205 static inline int \
206 register_trace_prio_##name(void (*probe)(data_proto), void *data,\
207 int prio) \
208 { \
209 return tracepoint_probe_register_prio(&__tracepoint_##name, \
210 (void *)probe, data, prio); \
211 } \
212 static inline int \
213 unregister_trace_##name(void (*probe)(data_proto), void *data) \
214 { \
215 return tracepoint_probe_unregister(&__tracepoint_##name,\
216 (void *)probe, data); \
217 } \
218 static inline void \
219 check_trace_callback_type_##name(void (*cb)(data_proto)) \
220 { \
221 } \
222 static inline bool \
223 trace_##name##_enabled(void) \
224 { \
225 return static_key_false(&__tracepoint_##name.key); \
226 }
227
228/*
229 * We have no guarantee that gcc and the linker won't up-align the tracepoint
230 * structures, so we create an array of pointers that will be used for iteration
231 * on the tracepoints.
232 */
233#define DEFINE_TRACE_FN(name, reg, unreg) \
234 static const char __tpstrtab_##name[] \
235 __attribute__((section("__tracepoints_strings"))) = #name; \
236 struct tracepoint __tracepoint_##name \
237 __attribute__((section("__tracepoints"))) = \
238 { __tpstrtab_##name, STATIC_KEY_INIT_FALSE, reg, unreg, NULL };\
239 static struct tracepoint * const __tracepoint_ptr_##name __used \
240 __attribute__((section("__tracepoints_ptrs"))) = \
241 &__tracepoint_##name;
242
243#define DEFINE_TRACE(name) \
244 DEFINE_TRACE_FN(name, NULL, NULL);
245
246#define EXPORT_TRACEPOINT_SYMBOL_GPL(name) \
247 EXPORT_SYMBOL_GPL(__tracepoint_##name)
248#define EXPORT_TRACEPOINT_SYMBOL(name) \
249 EXPORT_SYMBOL(__tracepoint_##name)
250
251#else /* !TRACEPOINTS_ENABLED */
252#define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args) \
253 static inline void trace_##name(proto) \
254 { } \
255 static inline void trace_##name##_rcuidle(proto) \
256 { } \
257 static inline int \
258 register_trace_##name(void (*probe)(data_proto), \
259 void *data) \
260 { \
261 return -ENOSYS; \
262 } \
263 static inline int \
264 unregister_trace_##name(void (*probe)(data_proto), \
265 void *data) \
266 { \
267 return -ENOSYS; \
268 } \
269 static inline void check_trace_callback_type_##name(void (*cb)(data_proto)) \
270 { \
271 } \
272 static inline bool \
273 trace_##name##_enabled(void) \
274 { \
275 return false; \
276 }
277
278#define DEFINE_TRACE_FN(name, reg, unreg)
279#define DEFINE_TRACE(name)
280#define EXPORT_TRACEPOINT_SYMBOL_GPL(name)
281#define EXPORT_TRACEPOINT_SYMBOL(name)
282
283#endif /* TRACEPOINTS_ENABLED */
284
285#ifdef CONFIG_TRACING
286/**
287 * tracepoint_string - register constant persistent string to trace system
288 * @str - a constant persistent string that will be referenced in tracepoints
289 *
290 * If constant strings are being used in tracepoints, it is faster and
291 * more efficient to just save the pointer to the string and reference
292 * that with a printf "%s" instead of saving the string in the ring buffer
293 * and wasting space and time.
294 *
295 * The problem with the above approach is that userspace tools that read
296 * the binary output of the trace buffers do not have access to the string.
297 * Instead they just show the address of the string which is not very
298 * useful to users.
299 *
300 * With tracepoint_string(), the string will be registered to the tracing
301 * system and exported to userspace via the debugfs/tracing/printk_formats
302 * file that maps the string address to the string text. This way userspace
303 * tools that read the binary buffers have a way to map the pointers to
304 * the ASCII strings they represent.
305 *
306 * The @str used must be a constant string and persistent as it would not
307 * make sense to show a string that no longer exists. But it is still fine
308 * to be used with modules, because when modules are unloaded, if they
309 * had tracepoints, the ring buffers are cleared too. As long as the string
310 * does not change during the life of the module, it is fine to use
311 * tracepoint_string() within a module.
312 */
313#define tracepoint_string(str) \
314 ({ \
315 static const char *___tp_str __tracepoint_string = str; \
316 ___tp_str; \
317 })
318#define __tracepoint_string __attribute__((section("__tracepoint_str")))
319#else
320/*
321 * tracepoint_string() is used to save the string address for userspace
322 * tracing tools. When tracing isn't configured, there's no need to save
323 * anything.
324 */
325# define tracepoint_string(str) str
326# define __tracepoint_string
327#endif
328
329/*
330 * The need for the DECLARE_TRACE_NOARGS() is to handle the prototype
331 * (void). "void" is a special value in a function prototype and can
332 * not be combined with other arguments. Since the DECLARE_TRACE()
333 * macro adds a data element at the beginning of the prototype,
334 * we need a way to differentiate "(void *data, proto)" from
335 * "(void *data, void)". The second prototype is invalid.
336 *
337 * DECLARE_TRACE_NOARGS() passes "void" as the tracepoint prototype
338 * and "void *__data" as the callback prototype.
339 *
340 * DECLARE_TRACE() passes "proto" as the tracepoint protoype and
341 * "void *__data, proto" as the callback prototype.
342 */
343#define DECLARE_TRACE_NOARGS(name) \
344 __DECLARE_TRACE(name, void, , \
345 cpu_online(raw_smp_processor_id()), \
346 void *__data, __data)
347
348#define DECLARE_TRACE(name, proto, args) \
349 __DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), \
350 cpu_online(raw_smp_processor_id()), \
351 PARAMS(void *__data, proto), \
352 PARAMS(__data, args))
353
354#define DECLARE_TRACE_CONDITION(name, proto, args, cond) \
355 __DECLARE_TRACE(name, PARAMS(proto), PARAMS(args), \
356 cpu_online(raw_smp_processor_id()) && (PARAMS(cond)), \
357 PARAMS(void *__data, proto), \
358 PARAMS(__data, args))
359
360#define TRACE_EVENT_FLAGS(event, flag)
361
362#define TRACE_EVENT_PERF_PERM(event, expr...)
363
364#endif /* DECLARE_TRACE */
365
366#ifndef TRACE_EVENT
367/*
368 * For use with the TRACE_EVENT macro:
369 *
370 * We define a tracepoint, its arguments, its printk format
371 * and its 'fast binary record' layout.
372 *
373 * Firstly, name your tracepoint via TRACE_EVENT(name : the
374 * 'subsystem_event' notation is fine.
375 *
376 * Think about this whole construct as the
377 * 'trace_sched_switch() function' from now on.
378 *
379 *
380 * TRACE_EVENT(sched_switch,
381 *
382 * *
383 * * A function has a regular function arguments
384 * * prototype, declare it via TP_PROTO():
385 * *
386 *
387 * TP_PROTO(struct rq *rq, struct task_struct *prev,
388 * struct task_struct *next),
389 *
390 * *
391 * * Define the call signature of the 'function'.
392 * * (Design sidenote: we use this instead of a
393 * * TP_PROTO1/TP_PROTO2/TP_PROTO3 ugliness.)
394 * *
395 *
396 * TP_ARGS(rq, prev, next),
397 *
398 * *
399 * * Fast binary tracing: define the trace record via
400 * * TP_STRUCT__entry(). You can think about it like a
401 * * regular C structure local variable definition.
402 * *
403 * * This is how the trace record is structured and will
404 * * be saved into the ring buffer. These are the fields
405 * * that will be exposed to user-space in
406 * * /sys/kernel/debug/tracing/events/<*>/format.
407 * *
408 * * The declared 'local variable' is called '__entry'
409 * *
410 * * __field(pid_t, prev_prid) is equivalent to a standard declariton:
411 * *
412 * * pid_t prev_pid;
413 * *
414 * * __array(char, prev_comm, TASK_COMM_LEN) is equivalent to:
415 * *
416 * * char prev_comm[TASK_COMM_LEN];
417 * *
418 *
419 * TP_STRUCT__entry(
420 * __array( char, prev_comm, TASK_COMM_LEN )
421 * __field( pid_t, prev_pid )
422 * __field( int, prev_prio )
423 * __array( char, next_comm, TASK_COMM_LEN )
424 * __field( pid_t, next_pid )
425 * __field( int, next_prio )
426 * ),
427 *
428 * *
429 * * Assign the entry into the trace record, by embedding
430 * * a full C statement block into TP_fast_assign(). You
431 * * can refer to the trace record as '__entry' -
432 * * otherwise you can put arbitrary C code in here.
433 * *
434 * * Note: this C code will execute every time a trace event
435 * * happens, on an active tracepoint.
436 * *
437 *
438 * TP_fast_assign(
439 * memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN);
440 * __entry->prev_pid = prev->pid;
441 * __entry->prev_prio = prev->prio;
442 * memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN);
443 * __entry->next_pid = next->pid;
444 * __entry->next_prio = next->prio;
445 * ),
446 *
447 * *
448 * * Formatted output of a trace record via TP_printk().
449 * * This is how the tracepoint will appear under ftrace
450 * * plugins that make use of this tracepoint.
451 * *
452 * * (raw-binary tracing wont actually perform this step.)
453 * *
454 *
455 * TP_printk("task %s:%d [%d] ==> %s:%d [%d]",
456 * __entry->prev_comm, __entry->prev_pid, __entry->prev_prio,
457 * __entry->next_comm, __entry->next_pid, __entry->next_prio),
458 *
459 * );
460 *
461 * This macro construct is thus used for the regular printk format
462 * tracing setup, it is used to construct a function pointer based
463 * tracepoint callback (this is used by programmatic plugins and
464 * can also by used by generic instrumentation like SystemTap), and
465 * it is also used to expose a structured trace record in
466 * /sys/kernel/debug/tracing/events/.
467 *
468 * A set of (un)registration functions can be passed to the variant
469 * TRACE_EVENT_FN to perform any (un)registration work.
470 */
471
472#define DECLARE_EVENT_CLASS(name, proto, args, tstruct, assign, print)
473#define DEFINE_EVENT(template, name, proto, args) \
474 DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
475#define DEFINE_EVENT_FN(template, name, proto, args, reg, unreg)\
476 DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
477#define DEFINE_EVENT_PRINT(template, name, proto, args, print) \
478 DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
479#define DEFINE_EVENT_CONDITION(template, name, proto, \
480 args, cond) \
481 DECLARE_TRACE_CONDITION(name, PARAMS(proto), \
482 PARAMS(args), PARAMS(cond))
483
484#define TRACE_EVENT(name, proto, args, struct, assign, print) \
485 DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
486#define TRACE_EVENT_FN(name, proto, args, struct, \
487 assign, print, reg, unreg) \
488 DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
489#define TRACE_EVENT_FN_COND(name, proto, args, cond, struct, \
490 assign, print, reg, unreg) \
491 DECLARE_TRACE_CONDITION(name, PARAMS(proto), \
492 PARAMS(args), PARAMS(cond))
493#define TRACE_EVENT_CONDITION(name, proto, args, cond, \
494 struct, assign, print) \
495 DECLARE_TRACE_CONDITION(name, PARAMS(proto), \
496 PARAMS(args), PARAMS(cond))
497
498#define TRACE_EVENT_FLAGS(event, flag)
499
500#define TRACE_EVENT_PERF_PERM(event, expr...)
501
502#endif /* ifdef TRACE_EVENT (see note above) */