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x86: Use tracepoint_enabled() for msr tracepoints instead of open coding it 

7f47d8cc03 ("x86, tracing, perf: Add trace point for MSR accesses") added
tracing of msr read and write, but because of complexity in having
tracepoints in headers, and even more so for a core header like msr.h, not
to mention the bloat a tracepoint adds to inline functions, a helper
function is needed to be called from the header.

Use the new tracepoint_enabled() macro in tracepoint-defs.h to test if the
tracepoint is active before calling the helper function, instead of open
coding the same logic, which requires knowing the internals of a tracepoint.

Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt (VMware) 2020-09-25 15:31:44 -04:00
parent c65fc2276f
commit fdb46faeab
1 changed files with 9 additions and 11 deletions
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20
arch/x86/include/asm/msr.h
View File

@ -60,22 +60,20 @@ struct saved_msrs {
#define EAX_EDX_RET(val, low, high) "=A" (val) #define EAX_EDX_RET(val, low, high) "=A" (val)
#endif #endif
#ifdef CONFIG_TRACEPOINTS
/* /*
* Be very careful with includes. This header is prone to include loops. * Be very careful with includes. This header is prone to include loops.
*/ */
#include <asm/atomic.h> #include <asm/atomic.h>
#include <linux/tracepoint-defs.h> #include <linux/tracepoint-defs.h>
extern struct tracepoint __tracepoint_read_msr; #ifdef CONFIG_TRACEPOINTS
extern struct tracepoint __tracepoint_write_msr; DECLARE_TRACEPOINT(read_msr);
extern struct tracepoint __tracepoint_rdpmc; DECLARE_TRACEPOINT(write_msr);
#define msr_tracepoint_active(t) static_key_false(&(t).key) DECLARE_TRACEPOINT(rdpmc);
extern void do_trace_write_msr(unsigned int msr, u64 val, int failed); extern void do_trace_write_msr(unsigned int msr, u64 val, int failed);
extern void do_trace_read_msr(unsigned int msr, u64 val, int failed); extern void do_trace_read_msr(unsigned int msr, u64 val, int failed);
extern void do_trace_rdpmc(unsigned int msr, u64 val, int failed); extern void do_trace_rdpmc(unsigned int msr, u64 val, int failed);
#else #else
#define msr_tracepoint_active(t) false
static inline void do_trace_write_msr(unsigned int msr, u64 val, int failed) {} static inline void do_trace_write_msr(unsigned int msr, u64 val, int failed) {}
static inline void do_trace_read_msr(unsigned int msr, u64 val, int failed) {} static inline void do_trace_read_msr(unsigned int msr, u64 val, int failed) {}
static inline void do_trace_rdpmc(unsigned int msr, u64 val, int failed) {} static inline void do_trace_rdpmc(unsigned int msr, u64 val, int failed) {}
@ -128,7 +126,7 @@ static inline unsigned long long native_read_msr(unsigned int msr)
val = __rdmsr(msr); val = __rdmsr(msr);
if (msr_tracepoint_active(__tracepoint_read_msr)) if (tracepoint_enabled(read_msr))
do_trace_read_msr(msr, val, 0); do_trace_read_msr(msr, val, 0);
return val; return val;
@ -150,7 +148,7 @@ static inline unsigned long long native_read_msr_safe(unsigned int msr,
_ASM_EXTABLE(2b, 3b) _ASM_EXTABLE(2b, 3b)
: [err] "=r" (*err), EAX_EDX_RET(val, low, high) : [err] "=r" (*err), EAX_EDX_RET(val, low, high)
: "c" (msr), [fault] "i" (-EIO)); : "c" (msr), [fault] "i" (-EIO));
if (msr_tracepoint_active(__tracepoint_read_msr)) if (tracepoint_enabled(read_msr))
do_trace_read_msr(msr, EAX_EDX_VAL(val, low, high), *err); do_trace_read_msr(msr, EAX_EDX_VAL(val, low, high), *err);
return EAX_EDX_VAL(val, low, high); return EAX_EDX_VAL(val, low, high);
} }
@ -161,7 +159,7 @@ native_write_msr(unsigned int msr, u32 low, u32 high)
{ {
__wrmsr(msr, low, high); __wrmsr(msr, low, high);
if (msr_tracepoint_active(__tracepoint_write_msr)) if (tracepoint_enabled(write_msr))
do_trace_write_msr(msr, ((u64)high << 32 | low), 0); do_trace_write_msr(msr, ((u64)high << 32 | low), 0);
} }
@ -181,7 +179,7 @@ native_write_msr_safe(unsigned int msr, u32 low, u32 high)
: "c" (msr), "0" (low), "d" (high), : "c" (msr), "0" (low), "d" (high),
[fault] "i" (-EIO) [fault] "i" (-EIO)
: "memory"); : "memory");
if (msr_tracepoint_active(__tracepoint_write_msr)) if (tracepoint_enabled(write_msr))
do_trace_write_msr(msr, ((u64)high << 32 | low), err); do_trace_write_msr(msr, ((u64)high << 32 | low), err);
return err; return err;
} }
@ -248,7 +246,7 @@ static inline unsigned long long native_read_pmc(int counter)
DECLARE_ARGS(val, low, high); DECLARE_ARGS(val, low, high);
asm volatile("rdpmc" : EAX_EDX_RET(val, low, high) : "c" (counter)); asm volatile("rdpmc" : EAX_EDX_RET(val, low, high) : "c" (counter));
if (msr_tracepoint_active(__tracepoint_rdpmc)) if (tracepoint_enabled(rdpmc))
do_trace_rdpmc(counter, EAX_EDX_VAL(val, low, high), 0); do_trace_rdpmc(counter, EAX_EDX_VAL(val, low, high), 0);
return EAX_EDX_VAL(val, low, high); return EAX_EDX_VAL(val, low, high);
} }