Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753557Ab3DUQuA (ORCPT ); Sun, 21 Apr 2013 12:50:00 -0400 Received: from mga02.intel.com ([134.134.136.20]:31124 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753437Ab3DUQt7 (ORCPT ); Sun, 21 Apr 2013 12:49:59 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.87,520,1363158000"; d="scan'208";a="298519245" From: Andi Kleen To: x86@kernel.org Cc: linux-kernel@vger.kernel.org, Andi Kleen Subject: [PATCH] x86: Fix AMD K6 indirect call check v2 Date: Sun, 21 Apr 2013 09:49:55 -0700 Message-Id: <1366562995-20530-1-git-send-email-andi@firstfloor.org> X-Mailer: git-send-email 1.7.7.6 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1010 Lines: 31 From: Andi Kleen 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. Found during code review, no runtime testing due to lack of hardware. v2: More description Signed-off-by: Andi Kleen diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index 4a549db..11ea6f6 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -115,7 +115,7 @@ static void __cpuinit init_amd_k6(struct cpuinfo_x86 *c) */ n = K6_BUG_LOOP; - f_vide = vide; + asm("" : "=g" (f_vide) : "0" (vide)); rdtscl(d); while (n--) f_vide(); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/