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Commit cb9e35dc authored by Ingo Molnar's avatar Ingo Molnar
Browse files

x86: clean up rdtsc_barrier() use 



Impact: cleanup

Move rdtsc_barrier() use to vsyscall_64.c where it's relied on,
and point out its role in the context of its use.

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 895e0317

arch/x86/include/asm/tsc.h

+1 −5
Original line number Diff line number Diff line
@@ -44,11 +44,7 @@ static __always_inline cycles_t vget_cycles(void) 
	if (!cpu_has_tsc)

		return 0;

#endif

	rdtsc_barrier();

	cycles = (cycles_t)__native_read_tsc();

	rdtsc_barrier();



	return cycles;

	return (cycles_t)__native_read_tsc();

}



extern void tsc_init(void);

arch/x86/kernel/vsyscall_64.c

+9 −0
Original line number Diff line number Diff line
@@ -128,7 +128,16 @@ static __always_inline void do_vgettimeofday(struct timeval * tv) 
			gettimeofday(tv,NULL);

			return;

		}



		/*

		 * Surround the RDTSC by barriers, to make sure it's not

		 * speculated to outside the seqlock critical section and

		 * does not cause time warps:

		 */

		rdtsc_barrier();

		now = vread();

		rdtsc_barrier();



		base = __vsyscall_gtod_data.clock.cycle_last;

		mask = __vsyscall_gtod_data.clock.mask;

		mult = __vsyscall_gtod_data.clock.mult;