From: Ingo Molnar <mingo@elte.hu>
Date: Wed, 30 Jan 2008 12:32:39 +0000 (+0100)
Subject: x86: read_tsc sync
X-Git-Tag: v2.6.25-rc1~1143^2~420
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=f06e4ec1c15691b0cfd2397ae32214fa36c90d71;p=linux.git

x86: read_tsc sync

make native_read_tsc() always non-speculative.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---

diff --git a/arch/x86/kernel/rtc.c b/arch/x86/kernel/rtc.c
index c42cf1263882..276cb7073ab1 100644
--- a/arch/x86/kernel/rtc.c
+++ b/arch/x86/kernel/rtc.c
@@ -200,7 +200,10 @@ unsigned long long __vsyscall_fn native_read_tsc(void)
 {
 	DECLARE_ARGS(val, low, high);
 
+	rdtsc_barrier();
 	asm volatile("rdtsc" : EAX_EDX_RET(val, low, high));
+	rdtsc_barrier();
+
 	return EAX_EDX_VAL(val, low, high);
 }
 EXPORT_SYMBOL_GPL(native_read_tsc);