Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
tracing: move tracing declarations from kernel.h to a dedicated header
Tracing is a half of the kernel.h in terms of LOCs, although it's a
self-consistent part. It is intended for quick debugging purposes and
isn't used by the normal tracing utilities.
Move it to a separate header. If someone needs to just throw a
trace_printk() in their driver, they will not have to pull all the heavy
tracing machinery.
This is a pure move.
Link: https://lkml.kernel.org/r/20260116042510.241009-7-ynorov@nvidia.com
Signed-off-by: Yury Norov <ynorov@nvidia.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com>
Cc: Aaron Tomlin <atomlin@atomlin.com>
Cc: Andi Shyti <andi.shyti@linux.intel.com>
Cc: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Petr Pavlu <petr.pavlu@suse.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
authored by
Yury Norov
and committed by
Andrew Morton
bec261fe
86e685ff
+205
-195
+1
-195
include/linux/kernel.h
+1
-195
include/linux/kernel.h
···
31
31
#include <linux/build_bug.h>
32
32
#include <linux/sprintf.h>
33
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#include <linux/static_call_types.h>
34
-
#include <linux/instruction_pointer.h>
34
+
#include <linux/trace_printk.h>
35
35
#include <linux/util_macros.h>
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36
#include <linux/wordpart.h>
37
37
···
188
188
SYSTEM_SUSPEND,
189
189
};
190
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extern enum system_states system_state;
191
-
192
-
/*
193
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* General tracing related utility functions - trace_printk(),
194
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* tracing_on/tracing_off and tracing_start()/tracing_stop
195
-
*
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* Use tracing_on/tracing_off when you want to quickly turn on or off
197
-
* tracing. It simply enables or disables the recording of the trace events.
198
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* This also corresponds to the user space /sys/kernel/tracing/tracing_on
199
-
* file, which gives a means for the kernel and userspace to interact.
200
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* Place a tracing_off() in the kernel where you want tracing to end.
201
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* From user space, examine the trace, and then echo 1 > tracing_on
202
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* to continue tracing.
203
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*
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* tracing_stop/tracing_start has slightly more overhead. It is used
205
-
* by things like suspend to ram where disabling the recording of the
206
-
* trace is not enough, but tracing must actually stop because things
207
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* like calling smp_processor_id() may crash the system.
208
-
*
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* Most likely, you want to use tracing_on/tracing_off.
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-
*/
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-
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enum ftrace_dump_mode {
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DUMP_NONE,
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DUMP_ALL,
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DUMP_ORIG,
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DUMP_PARAM,
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-
};
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-
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-
#ifdef CONFIG_TRACING
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void tracing_on(void);
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void tracing_off(void);
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int tracing_is_on(void);
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-
void tracing_snapshot(void);
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void tracing_snapshot_alloc(void);
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-
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extern void tracing_start(void);
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extern void tracing_stop(void);
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-
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static inline __printf(1, 2)
230
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void ____trace_printk_check_format(const char *fmt, ...)
231
-
{
232
-
}
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#define __trace_printk_check_format(fmt, args...) \
234
-
do { \
235
-
if (0) \
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____trace_printk_check_format(fmt, ##args); \
237
-
} while (0)
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-
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/**
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* trace_printk - printf formatting in the ftrace buffer
241
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* @fmt: the printf format for printing
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*
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* Note: __trace_printk is an internal function for trace_printk() and
244
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* the @ip is passed in via the trace_printk() macro.
245
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*
246
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* This function allows a kernel developer to debug fast path sections
247
-
* that printk is not appropriate for. By scattering in various
248
-
* printk like tracing in the code, a developer can quickly see
249
-
* where problems are occurring.
250
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*
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* This is intended as a debugging tool for the developer only.
252
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* Please refrain from leaving trace_printks scattered around in
253
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* your code. (Extra memory is used for special buffers that are
254
-
* allocated when trace_printk() is used.)
255
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*
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* A little optimization trick is done here. If there's only one
257
-
* argument, there's no need to scan the string for printf formats.
258
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* The trace_puts() will suffice. But how can we take advantage of
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* using trace_puts() when trace_printk() has only one argument?
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* By stringifying the args and checking the size we can tell
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* whether or not there are args. __stringify((__VA_ARGS__)) will
262
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* turn into "()\0" with a size of 3 when there are no args, anything
263
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* else will be bigger. All we need to do is define a string to this,
264
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* and then take its size and compare to 3. If it's bigger, use
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* do_trace_printk() otherwise, optimize it to trace_puts(). Then just
266
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* let gcc optimize the rest.
267
-
*/
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-
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#define trace_printk(fmt, ...) \
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do { \
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char _______STR[] = __stringify((__VA_ARGS__)); \
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-
if (sizeof(_______STR) > 3) \
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do_trace_printk(fmt, ##__VA_ARGS__); \
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-
else \
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trace_puts(fmt); \
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} while (0)
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-
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#define do_trace_printk(fmt, args...) \
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do { \
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static const char *trace_printk_fmt __used \
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__section("__trace_printk_fmt") = \
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__builtin_constant_p(fmt) ? fmt : NULL; \
283
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\
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__trace_printk_check_format(fmt, ##args); \
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\
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if (__builtin_constant_p(fmt)) \
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__trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args); \
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else \
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__trace_printk(_THIS_IP_, fmt, ##args); \
290
-
} while (0)
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-
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extern __printf(2, 3)
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int __trace_bprintk(unsigned long ip, const char *fmt, ...);
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-
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extern __printf(2, 3)
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int __trace_printk(unsigned long ip, const char *fmt, ...);
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-
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/**
299
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* trace_puts - write a string into the ftrace buffer
300
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* @str: the string to record
301
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*
302
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* Note: __trace_bputs is an internal function for trace_puts and
303
-
* the @ip is passed in via the trace_puts macro.
304
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*
305
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* This is similar to trace_printk() but is made for those really fast
306
-
* paths that a developer wants the least amount of "Heisenbug" effects,
307
-
* where the processing of the print format is still too much.
308
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*
309
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* This function allows a kernel developer to debug fast path sections
310
-
* that printk is not appropriate for. By scattering in various
311
-
* printk like tracing in the code, a developer can quickly see
312
-
* where problems are occurring.
313
-
*
314
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* This is intended as a debugging tool for the developer only.
315
-
* Please refrain from leaving trace_puts scattered around in
316
-
* your code. (Extra memory is used for special buffers that are
317
-
* allocated when trace_puts() is used.)
318
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*
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* Returns: 0 if nothing was written, positive # if string was.
320
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* (1 when __trace_bputs is used, strlen(str) when __trace_puts is used)
321
-
*/
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-
323
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#define trace_puts(str) ({ \
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static const char *trace_printk_fmt __used \
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__section("__trace_printk_fmt") = \
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__builtin_constant_p(str) ? str : NULL; \
327
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\
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if (__builtin_constant_p(str)) \
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__trace_bputs(_THIS_IP_, trace_printk_fmt); \
330
-
else \
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__trace_puts(_THIS_IP_, str); \
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-
})
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extern int __trace_bputs(unsigned long ip, const char *str);
334
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extern int __trace_puts(unsigned long ip, const char *str);
335
-
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extern void trace_dump_stack(int skip);
337
-
338
-
/*
339
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* The double __builtin_constant_p is because gcc will give us an error
340
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* if we try to allocate the static variable to fmt if it is not a
341
-
* constant. Even with the outer if statement.
342
-
*/
343
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#define ftrace_vprintk(fmt, vargs) \
344
-
do { \
345
-
if (__builtin_constant_p(fmt)) { \
346
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static const char *trace_printk_fmt __used \
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__section("__trace_printk_fmt") = \
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__builtin_constant_p(fmt) ? fmt : NULL; \
349
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\
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__ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs); \
351
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} else \
352
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__ftrace_vprintk(_THIS_IP_, fmt, vargs); \
353
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} while (0)
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-
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extern __printf(2, 0) int
356
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__ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
357
-
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extern __printf(2, 0) int
359
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__ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
360
-
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extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
362
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#else
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static inline void tracing_start(void) { }
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static inline void tracing_stop(void) { }
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static inline void trace_dump_stack(int skip) { }
366
-
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static inline void tracing_on(void) { }
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static inline void tracing_off(void) { }
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static inline int tracing_is_on(void) { return 0; }
370
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static inline void tracing_snapshot(void) { }
371
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static inline void tracing_snapshot_alloc(void) { }
372
-
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static inline __printf(1, 2)
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int trace_printk(const char *fmt, ...)
375
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{
376
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return 0;
377
-
}
378
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static __printf(1, 0) inline int
379
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ftrace_vprintk(const char *fmt, va_list ap)
380
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{
381
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return 0;
382
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}
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static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
384
-
#endif /* CONFIG_TRACING */
385
191
386
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/* Rebuild everything on CONFIG_DYNAMIC_FTRACE */
387
193
#ifdef CONFIG_DYNAMIC_FTRACE
+204
include/linux/trace_printk.h
+204
include/linux/trace_printk.h
···
1
+
/* SPDX-License-Identifier: GPL-2.0 */
2
+
#ifndef _LINUX_TRACE_PRINTK_H
3
+
#define _LINUX_TRACE_PRINTK_H
4
+
5
+
#include <linux/compiler_attributes.h>
6
+
#include <linux/instruction_pointer.h>
7
+
#include <linux/stddef.h>
8
+
#include <linux/stringify.h>
9
+
10
+
/*
11
+
* General tracing related utility functions - trace_printk(),
12
+
* tracing_on/tracing_off and tracing_start()/tracing_stop
13
+
*
14
+
* Use tracing_on/tracing_off when you want to quickly turn on or off
15
+
* tracing. It simply enables or disables the recording of the trace events.
16
+
* This also corresponds to the user space /sys/kernel/tracing/tracing_on
17
+
* file, which gives a means for the kernel and userspace to interact.
18
+
* Place a tracing_off() in the kernel where you want tracing to end.
19
+
* From user space, examine the trace, and then echo 1 > tracing_on
20
+
* to continue tracing.
21
+
*
22
+
* tracing_stop/tracing_start has slightly more overhead. It is used
23
+
* by things like suspend to ram where disabling the recording of the
24
+
* trace is not enough, but tracing must actually stop because things
25
+
* like calling smp_processor_id() may crash the system.
26
+
*
27
+
* Most likely, you want to use tracing_on/tracing_off.
28
+
*/
29
+
30
+
enum ftrace_dump_mode {
31
+
DUMP_NONE,
32
+
DUMP_ALL,
33
+
DUMP_ORIG,
34
+
DUMP_PARAM,
35
+
};
36
+
37
+
#ifdef CONFIG_TRACING
38
+
void tracing_on(void);
39
+
void tracing_off(void);
40
+
int tracing_is_on(void);
41
+
void tracing_snapshot(void);
42
+
void tracing_snapshot_alloc(void);
43
+
44
+
extern void tracing_start(void);
45
+
extern void tracing_stop(void);
46
+
47
+
static inline __printf(1, 2)
48
+
void ____trace_printk_check_format(const char *fmt, ...)
49
+
{
50
+
}
51
+
#define __trace_printk_check_format(fmt, args...) \
52
+
do { \
53
+
if (0) \
54
+
____trace_printk_check_format(fmt, ##args); \
55
+
} while (0)
56
+
57
+
/**
58
+
* trace_printk - printf formatting in the ftrace buffer
59
+
* @fmt: the printf format for printing
60
+
*
61
+
* Note: __trace_printk is an internal function for trace_printk() and
62
+
* the @ip is passed in via the trace_printk() macro.
63
+
*
64
+
* This function allows a kernel developer to debug fast path sections
65
+
* that printk is not appropriate for. By scattering in various
66
+
* printk like tracing in the code, a developer can quickly see
67
+
* where problems are occurring.
68
+
*
69
+
* This is intended as a debugging tool for the developer only.
70
+
* Please refrain from leaving trace_printks scattered around in
71
+
* your code. (Extra memory is used for special buffers that are
72
+
* allocated when trace_printk() is used.)
73
+
*
74
+
* A little optimization trick is done here. If there's only one
75
+
* argument, there's no need to scan the string for printf formats.
76
+
* The trace_puts() will suffice. But how can we take advantage of
77
+
* using trace_puts() when trace_printk() has only one argument?
78
+
* By stringifying the args and checking the size we can tell
79
+
* whether or not there are args. __stringify((__VA_ARGS__)) will
80
+
* turn into "()\0" with a size of 3 when there are no args, anything
81
+
* else will be bigger. All we need to do is define a string to this,
82
+
* and then take its size and compare to 3. If it's bigger, use
83
+
* do_trace_printk() otherwise, optimize it to trace_puts(). Then just
84
+
* let gcc optimize the rest.
85
+
*/
86
+
87
+
#define trace_printk(fmt, ...) \
88
+
do { \
89
+
char _______STR[] = __stringify((__VA_ARGS__)); \
90
+
if (sizeof(_______STR) > 3) \
91
+
do_trace_printk(fmt, ##__VA_ARGS__); \
92
+
else \
93
+
trace_puts(fmt); \
94
+
} while (0)
95
+
96
+
#define do_trace_printk(fmt, args...) \
97
+
do { \
98
+
static const char *trace_printk_fmt __used \
99
+
__section("__trace_printk_fmt") = \
100
+
__builtin_constant_p(fmt) ? fmt : NULL; \
101
+
\
102
+
__trace_printk_check_format(fmt, ##args); \
103
+
\
104
+
if (__builtin_constant_p(fmt)) \
105
+
__trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args); \
106
+
else \
107
+
__trace_printk(_THIS_IP_, fmt, ##args); \
108
+
} while (0)
109
+
110
+
extern __printf(2, 3)
111
+
int __trace_bprintk(unsigned long ip, const char *fmt, ...);
112
+
113
+
extern __printf(2, 3)
114
+
int __trace_printk(unsigned long ip, const char *fmt, ...);
115
+
116
+
/**
117
+
* trace_puts - write a string into the ftrace buffer
118
+
* @str: the string to record
119
+
*
120
+
* Note: __trace_bputs is an internal function for trace_puts and
121
+
* the @ip is passed in via the trace_puts macro.
122
+
*
123
+
* This is similar to trace_printk() but is made for those really fast
124
+
* paths that a developer wants the least amount of "Heisenbug" effects,
125
+
* where the processing of the print format is still too much.
126
+
*
127
+
* This function allows a kernel developer to debug fast path sections
128
+
* that printk is not appropriate for. By scattering in various
129
+
* printk like tracing in the code, a developer can quickly see
130
+
* where problems are occurring.
131
+
*
132
+
* This is intended as a debugging tool for the developer only.
133
+
* Please refrain from leaving trace_puts scattered around in
134
+
* your code. (Extra memory is used for special buffers that are
135
+
* allocated when trace_puts() is used.)
136
+
*
137
+
* Returns: 0 if nothing was written, positive # if string was.
138
+
* (1 when __trace_bputs is used, strlen(str) when __trace_puts is used)
139
+
*/
140
+
141
+
#define trace_puts(str) ({ \
142
+
static const char *trace_printk_fmt __used \
143
+
__section("__trace_printk_fmt") = \
144
+
__builtin_constant_p(str) ? str : NULL; \
145
+
\
146
+
if (__builtin_constant_p(str)) \
147
+
__trace_bputs(_THIS_IP_, trace_printk_fmt); \
148
+
else \
149
+
__trace_puts(_THIS_IP_, str); \
150
+
})
151
+
extern int __trace_bputs(unsigned long ip, const char *str);
152
+
extern int __trace_puts(unsigned long ip, const char *str);
153
+
154
+
extern void trace_dump_stack(int skip);
155
+
156
+
/*
157
+
* The double __builtin_constant_p is because gcc will give us an error
158
+
* if we try to allocate the static variable to fmt if it is not a
159
+
* constant. Even with the outer if statement.
160
+
*/
161
+
#define ftrace_vprintk(fmt, vargs) \
162
+
do { \
163
+
if (__builtin_constant_p(fmt)) { \
164
+
static const char *trace_printk_fmt __used \
165
+
__section("__trace_printk_fmt") = \
166
+
__builtin_constant_p(fmt) ? fmt : NULL; \
167
+
\
168
+
__ftrace_vbprintk(_THIS_IP_, trace_printk_fmt, vargs); \
169
+
} else \
170
+
__ftrace_vprintk(_THIS_IP_, fmt, vargs); \
171
+
} while (0)
172
+
173
+
extern __printf(2, 0) int
174
+
__ftrace_vbprintk(unsigned long ip, const char *fmt, va_list ap);
175
+
176
+
extern __printf(2, 0) int
177
+
__ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
178
+
179
+
extern void ftrace_dump(enum ftrace_dump_mode oops_dump_mode);
180
+
#else
181
+
static inline void tracing_start(void) { }
182
+
static inline void tracing_stop(void) { }
183
+
static inline void trace_dump_stack(int skip) { }
184
+
185
+
static inline void tracing_on(void) { }
186
+
static inline void tracing_off(void) { }
187
+
static inline int tracing_is_on(void) { return 0; }
188
+
static inline void tracing_snapshot(void) { }
189
+
static inline void tracing_snapshot_alloc(void) { }
190
+
191
+
static inline __printf(1, 2)
192
+
int trace_printk(const char *fmt, ...)
193
+
{
194
+
return 0;
195
+
}
196
+
static __printf(1, 0) inline int
197
+
ftrace_vprintk(const char *fmt, va_list ap)
198
+
{
199
+
return 0;
200
+
}
201
+
static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { }
202
+
#endif /* CONFIG_TRACING */
203
+
204
+
#endif