Commit fdb46fae authored by Steven Rostedt (VMware)'s avatar Steven Rostedt (VMware)
Browse files

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



7f47d8cc ("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: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent c65fc227

arch/x86/include/asm/msr.h

+9 −11
Original line number Diff line number Diff line
@@ -60,22 +60,20 @@ struct saved_msrs { 
#define EAX_EDX_RET(val, low, high)	"=A" (val)

#endif



#ifdef CONFIG_TRACEPOINTS

/*

 * Be very careful with includes. This header is prone to include loops.

 */

#include <asm/atomic.h>

#include <linux/tracepoint-defs.h>



extern struct tracepoint __tracepoint_read_msr;

extern struct tracepoint __tracepoint_write_msr;

extern struct tracepoint __tracepoint_rdpmc;

#define msr_tracepoint_active(t) static_key_false(&(t).key)

#ifdef CONFIG_TRACEPOINTS

DECLARE_TRACEPOINT(read_msr);

DECLARE_TRACEPOINT(write_msr);

DECLARE_TRACEPOINT(rdpmc);

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_rdpmc(unsigned int msr, u64 val, int failed);

#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_read_msr(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);



	if (msr_tracepoint_active(__tracepoint_read_msr))

	if (tracepoint_enabled(read_msr))

		do_trace_read_msr(msr, val, 0);



	return val;
@@ -150,7 +148,7 @@ static inline unsigned long long native_read_msr_safe(unsigned int msr, 
		     _ASM_EXTABLE(2b, 3b)

		     : [err] "=r" (*err), EAX_EDX_RET(val, low, high)

		     : "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);

	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);



	if (msr_tracepoint_active(__tracepoint_write_msr))

	if (tracepoint_enabled(write_msr))

		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),

		       [fault] "i" (-EIO)

		     : "memory");

	if (msr_tracepoint_active(__tracepoint_write_msr))

	if (tracepoint_enabled(write_msr))

		do_trace_write_msr(msr, ((u64)high << 32 | low), err);

	return err;

}
@@ -248,7 +246,7 @@ static inline unsigned long long native_read_pmc(int counter) 
	DECLARE_ARGS(val, low, high);



	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);

	return EAX_EDX_VAL(val, low, high);

}

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