tracing: define TRACE_DEFINE_SIZEOF() macro to map sizeof's to their values

Perf has a problem that if sizeof() macros are used within TRACE_EVENT()
macro's they end up in userspace as "sizeof(kernel structure)" which
cannot properly be parsed. Add a macro which can forward this data
through the eval_map for userspace utilization.

Link: http://lkml.kernel.org/r/20170531215653.3240-10-jeremy.linton@arm.com

Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Jeremy Linton 2017-05-31 16:56:50 -05:00 committed by Steven Rostedt (VMware)
parent 67ec0d8595
commit 4f0dfd76e9
2 changed files with 17 additions and 0 deletions

View File

@ -88,6 +88,7 @@ extern void syscall_unregfunc(void);
#define PARAMS(args...) args
#define TRACE_DEFINE_ENUM(x)
#define TRACE_DEFINE_SIZEOF(x)
#endif /* _LINUX_TRACEPOINT_H */

View File

@ -46,6 +46,19 @@ TRACE_MAKE_SYSTEM_STR();
__attribute__((section("_ftrace_eval_map"))) \
*TRACE_SYSTEM##_##a = &__##TRACE_SYSTEM##_##a
#undef TRACE_DEFINE_SIZEOF
#define TRACE_DEFINE_SIZEOF(a) \
static struct trace_eval_map __used __initdata \
__##TRACE_SYSTEM##_##a = \
{ \
.system = TRACE_SYSTEM_STRING, \
.eval_string = "sizeof(" #a ")", \
.eval_value = sizeof(a) \
}; \
static struct trace_eval_map __used \
__attribute__((section("_ftrace_eval_map"))) \
*TRACE_SYSTEM##_##a = &__##TRACE_SYSTEM##_##a
/*
* DECLARE_EVENT_CLASS can be used to add a generic function
* handlers for events. That is, if all events have the same
@ -158,6 +171,9 @@ TRACE_MAKE_SYSTEM_STR();
#undef TRACE_DEFINE_ENUM
#define TRACE_DEFINE_ENUM(a)
#undef TRACE_DEFINE_SIZEOF
#define TRACE_DEFINE_SIZEOF(a)
#undef __field
#define __field(type, item)