From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756510Ab1JMSVx (ORCPT ); Thu, 13 Oct 2011 14:21:53 -0400 Received: from claw.goop.org ([74.207.240.146]:49954 "EHLO claw.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753553Ab1JMSVv (ORCPT ); Thu, 13 Oct 2011 14:21:51 -0400 Message-ID: <4E97188A.6040400@goop.org> Date: Thu, 13 Oct 2011 09:57:46 -0700 From: Jeremy Fitzhardinge User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:7.0.1) Gecko/20110930 Thunderbird/7.0.1 MIME-Version: 1.0 To: "H. Peter Anvin" CC: Steven Rostedt , "David S. Miller" , David Daney , Michael Ellerman , Jan Glauber , Jason Baron , the arch/x86 maintainers , Xen Devel , Linux Kernel Mailing List , Ingo Molnar , Peter Zijlstra , Jeremy Fitzhardinge Subject: Re: [PATCH RFC V4 09/10] x86/jump_label: use GENERIC_NOP5_ATOMIC instead of jmp5 +0 References: <34ede5db1571d541a5c3fc49923bb353a37dd431.1318464413.git.jeremy.fitzhardinge@citrix.com> <4E97067A.2070305@zytor.com> In-Reply-To: <4E97067A.2070305@zytor.com> X-Enigmail-Version: 1.3.2 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/13/2011 08:40 AM, H. Peter Anvin wrote: > On 10/12/2011 05:08 PM, Jeremy Fitzhardinge wrote: >> From: Jeremy Fitzhardinge >> >> GENERIC_NOP5_ATOMIC should make a better nop. >> > On 32 bits, yes. On 64 bits you should use P6_NOP5_ATOMIC. Something like this? From: Jeremy Fitzhardinge Date: Thu, 13 Oct 2011 09:55:25 -0700 Subject: [PATCH] x86/nop: we can use P6 as generic NOP on 64-bit Signed-off-by: Jeremy Fitzhardinge diff --git a/arch/x86/include/asm/nops.h b/arch/x86/include/asm/nops.h index 405b403..f9fead9 100644 --- a/arch/x86/include/asm/nops.h +++ b/arch/x86/include/asm/nops.h @@ -19,15 +19,15 @@ 6: leal 0x00000000(%esi),%esi 7: leal 0x00000000(,%esi,1),%esi */ -#define GENERIC_NOP1 0x90 -#define GENERIC_NOP2 0x89,0xf6 -#define GENERIC_NOP3 0x8d,0x76,0x00 -#define GENERIC_NOP4 0x8d,0x74,0x26,0x00 -#define GENERIC_NOP5 GENERIC_NOP1,GENERIC_NOP4 -#define GENERIC_NOP6 0x8d,0xb6,0x00,0x00,0x00,0x00 -#define GENERIC_NOP7 0x8d,0xb4,0x26,0x00,0x00,0x00,0x00 -#define GENERIC_NOP8 GENERIC_NOP1,GENERIC_NOP7 -#define GENERIC_NOP5_ATOMIC NOP_DS_PREFIX,GENERIC_NOP4 +#define GAS_NOP1 0x90 +#define GAS_NOP2 0x89,0xf6 +#define GAS_NOP3 0x8d,0x76,0x00 +#define GAS_NOP4 0x8d,0x74,0x26,0x00 +#define GAS_NOP5 GENERIC_NOP1,GENERIC_NOP4 +#define GAS_NOP6 0x8d,0xb6,0x00,0x00,0x00,0x00 +#define GAS_NOP7 0x8d,0xb4,0x26,0x00,0x00,0x00,0x00 +#define GAS_NOP8 GENERIC_NOP1,GENERIC_NOP7 +#define GAS_NOP5_ATOMIC NOP_DS_PREFIX,GENERIC_NOP4 /* Opteron 64bit nops 1: nop @@ -87,6 +87,28 @@ #define P6_NOP8 0x0f,0x1f,0x84,0x00,0,0,0,0 #define P6_NOP5_ATOMIC P6_NOP5 +#ifdef CONFIG_X86_32 +#define GENERIC_NOP1 GAS_NOP1 +#define GENERIC_NOP2 GAS_NOP2 +#define GENERIC_NOP3 GAS_NOP3 +#define GENERIC_NOP4 GAS_NOP4 +#define GENERIC_NOP5 GAS_NOP5 +#define GENERIC_NOP6 GAS_NOP6 +#define GENERIC_NOP7 GAS_NOP7 +#define GENERIC_NOP8 GAS_NOP8 +#define GENERIC_NOP5_ATOMIC GAS_NOP5_ATOMIC +#else +#define GENERIC_NOP1 P6_NOP1 +#define GENERIC_NOP2 P6_NOP2 +#define GENERIC_NOP3 P6_NOP3 +#define GENERIC_NOP4 P6_NOP4 +#define GENERIC_NOP5 P6_NOP5 +#define GENERIC_NOP6 P6_NOP6 +#define GENERIC_NOP7 P6_NOP7 +#define GENERIC_NOP8 P6_NOP8 +#define GENERIC_NOP5_ATOMIC P6_NOP5_ATOMIC +#endif + #define _ASM_MK_NOP(x) ".byte " __stringify(x) "\n" #if defined(CONFIG_MK7)