Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756262Ab0A2J1W (ORCPT ); Fri, 29 Jan 2010 04:27:22 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754929Ab0A2J1K (ORCPT ); Fri, 29 Jan 2010 04:27:10 -0500 Received: from hera.kernel.org ([140.211.167.34]:57346 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754675Ab0A2J1I (ORCPT ); Fri, 29 Jan 2010 04:27:08 -0500 Date: Fri, 29 Jan 2010 09:25:59 GMT From: "tip-bot for K.Prasad" Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, stern@rowland.harvard.edu, jan.kiszka@siemens.com, fweisbec@gmail.com, roland@redhat.com, tglx@linutronix.de, prasad@linux.vnet.ibm.com, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, stern@rowland.harvard.edu, jan.kiszka@siemens.com, fweisbec@gmail.com, roland@redhat.com, tglx@linutronix.de, mingo@elte.hu, prasad@linux.vnet.ibm.com In-Reply-To: <20100128111401.GB13935@in.ibm.com> References: <20100128111401.GB13935@in.ibm.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] x86/debug: Clear reserved bits of DR6 in do_debug() Message-ID: Git-Commit-ID: 40f9249a73f6c251adea492b1c3d19d39e2a9bda X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.3 (hera.kernel.org [127.0.0.1]); Fri, 29 Jan 2010 09:26:00 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2252 Lines: 59 Commit-ID: 40f9249a73f6c251adea492b1c3d19d39e2a9bda Gitweb: http://git.kernel.org/tip/40f9249a73f6c251adea492b1c3d19d39e2a9bda Author: K.Prasad AuthorDate: Thu, 28 Jan 2010 16:44:01 +0530 Committer: Frederic Weisbecker CommitDate: Fri, 29 Jan 2010 02:26:10 +0100 x86/debug: Clear reserved bits of DR6 in do_debug() Clear the reserved bits from the stored copy of debug status register (DR6). This will help easy bitwise operations such as quick testing of a debug event origin. Signed-off-by: K.Prasad Cc: Roland McGrath Cc: Jan Kiszka Cc: Alan Stern Cc: Ingo Molnar LKML-Reference: <20100128111401.GB13935@in.ibm.com> Signed-off-by: Frederic Weisbecker --- arch/x86/include/asm/debugreg.h | 3 +++ arch/x86/kernel/traps.c | 3 +++ 2 files changed, 6 insertions(+), 0 deletions(-) diff --git a/arch/x86/include/asm/debugreg.h b/arch/x86/include/asm/debugreg.h index 8240f76..b81002f 100644 --- a/arch/x86/include/asm/debugreg.h +++ b/arch/x86/include/asm/debugreg.h @@ -14,6 +14,9 @@ which debugging register was responsible for the trap. The other bits are either reserved or not of interest to us. */ +/* Define reserved bits in DR6 which are always set to 1 */ +#define DR6_RESERVED (0xFFFF0FF0) + #define DR_TRAP0 (0x1) /* db0 */ #define DR_TRAP1 (0x2) /* db1 */ #define DR_TRAP2 (0x4) /* db2 */ diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 3339917..1168e44 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -534,6 +534,9 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code) get_debugreg(dr6, 6); + /* Filter out all the reserved bits which are preset to 1 */ + dr6 &= ~DR6_RESERVED; + /* Catch kmemcheck conditions first of all! */ if ((dr6 & DR_STEP) && kmemcheck_trap(regs)) return; -- 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/