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[30/74] x86, lto: Fix AMD K6 indirect call check

Message ID 1345345030-22211-31-git-send-email-andi@firstfloor.org (mailing list archive)
State New, archived
Headers show

Commit Message

Andi Kleen Aug. 19, 2012, 2:56 a.m. UTC 
From: Andi Kleen <ak@linux.intel.com>

The AMD K6 errata check relies on timing a indirect call.
But the way it was written it could be optimized to a direct call.
Force gcc to actually do a indirect call and not just
constant resolve the target address.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
---
 arch/x86/kernel/cpu/amd.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
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Patch

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 2c02d92..cb72014 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -116,7 +116,7 @@  static void __cpuinit init_amd_k6(struct cpuinfo_x86 *c)
 		 */
 
 		n = K6_BUG_LOOP;
-		f_vide = vide;
+		asm("" : "=r" (f_vide) : "0" (vide));
 		rdtscl(d);
 		while (n--)
 			f_vide();