Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759481AbZKZJ4o (ORCPT ); Thu, 26 Nov 2009 04:56:44 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752304AbZKZJ4m (ORCPT ); Thu, 26 Nov 2009 04:56:42 -0500 Received: from hera.kernel.org ([140.211.167.34]:41429 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759370AbZKZJ4k (ORCPT ); Thu, 26 Nov 2009 04:56:40 -0500 Date: Thu, 26 Nov 2009 09:55:56 GMT From: tip-bot for Brian Gerst Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, brgerst@gmail.com, tglx@linutronix.de, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, brgerst@gmail.com, tglx@linutronix.de, mingo@elte.hu In-Reply-To: <1259176706-5908-1-git-send-email-brgerst@gmail.com> References: <1259176706-5908-1-git-send-email-brgerst@gmail.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/asm] x86: Optimize loadsegment() Message-ID: Git-Commit-ID: 79b0379cee09b00ef309384aff652e328e438c79 X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1836 Lines: 55 Commit-ID: 79b0379cee09b00ef309384aff652e328e438c79 Gitweb: http://git.kernel.org/tip/79b0379cee09b00ef309384aff652e328e438c79 Author: Brian Gerst AuthorDate: Wed, 25 Nov 2009 14:18:26 -0500 Committer: Ingo Molnar CommitDate: Thu, 26 Nov 2009 10:33:58 +0100 x86: Optimize loadsegment() Zero the input register in the exception handler instead of using an extra register to pass in a zero value. Signed-off-by: Brian Gerst LKML-Reference: <1259176706-5908-1-git-send-email-brgerst@gmail.com> Signed-off-by: Ingo Molnar --- arch/x86/include/asm/system.h | 15 ++++++++------- 1 files changed, 8 insertions(+), 7 deletions(-) diff --git a/arch/x86/include/asm/system.h b/arch/x86/include/asm/system.h index 1a953e2..537395a 100644 --- a/arch/x86/include/asm/system.h +++ b/arch/x86/include/asm/system.h @@ -156,18 +156,19 @@ extern void native_load_gs_index(unsigned); * segment if something goes wrong.. */ #define loadsegment(seg, value) \ +do { \ + unsigned short __val = value; \ asm volatile("\n" \ "1:\t" \ "movl %k0,%%" #seg "\n" \ - "2:\n" \ ".section .fixup,\"ax\"\n" \ - "3:\t" \ - "movl %k1, %%" #seg "\n\t" \ - "jmp 2b\n" \ + "2:\t" \ + "xorl %k0,%k0\n\t" \ + "jmp 1b\n" \ ".previous\n" \ - _ASM_EXTABLE(1b,3b) \ - : :"r" (value), "r" (0) : "memory") - + _ASM_EXTABLE(1b, 2b) \ + : "+r" (__val) : : "memory"); \ +} while (0) /* * Save a segment register away -- 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/