---

yaml --- r: 120768 b: refs/heads/master c: cb9e35d h: refs/heads/master v: v3
git-mirror · Nov 8, 2008 · 312d89a · 312d89a
1 parent da16e8c
commit 312d89a
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Showing 3 changed files with 11 additions and 6 deletions.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 895e031707954a9ca26ed4f5f794575313854ed1
+refs/heads/master: cb9e35dce94a1b9c59d46224e8a94377d673e204
diff --git a/trunk/arch/x86/include/asm/tsc.h b/trunk/arch/x86/include/asm/tsc.h
@@ -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);

diff --git a/trunk/arch/x86/kernel/vsyscall_64.c b/trunk/arch/x86/kernel/vsyscall_64.c
@@ -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;