Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752779Ab3FRELo (ORCPT ); Tue, 18 Jun 2013 00:11:44 -0400 Received: from mx1.redhat.com ([209.132.183.28]:13705 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750855Ab3FRELn (ORCPT ); Tue, 18 Jun 2013 00:11:43 -0400 Date: Tue, 18 Jun 2013 00:11:32 -0400 From: Dave Jones To: Linux Kernel Cc: x86@kernel.org Subject: [x86] only print out DR registers if they are not power-on defaults. Message-ID: <20130618041132.GA23492@redhat.com> Mail-Followup-To: Dave Jones , Linux Kernel , x86@kernel.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2357 Lines: 60 The DR registers are rarely useful when decoding oopses. With screen real estate during oopses at a premium, we can save two lines by only printing out these registers when they are set to something other than they power-on state. Signed-off-by: Dave Jones diff -durpN '--exclude-from=/home/davej/.exclude' /home/davej/src/kernel/git-trees/linux/arch/x86/kernel/process_64.c linux-dj/arch/x86/kernel/process_64.c --- /home/davej/src/kernel/git-trees/linux/arch/x86/kernel/process_64.c 2013-05-01 10:02:52.064151923 -0400 +++ linux-dj/arch/x86/kernel/process_64.c 2013-05-06 20:35:09.219868881 -0400 @@ -105,11 +105,18 @@ void __show_regs(struct pt_regs *regs, i get_debugreg(d0, 0); get_debugreg(d1, 1); get_debugreg(d2, 2); - printk(KERN_DEFAULT "DR0: %016lx DR1: %016lx DR2: %016lx\n", d0, d1, d2); get_debugreg(d3, 3); get_debugreg(d6, 6); get_debugreg(d7, 7); + + /* Only print out debug registers if they are in their non-default state. */ + if ((d0 == 0) && (d1 == 0) && (d2 == 0) && (d3 == 0) && + (d6 & ~DR6_RESERVED) && (d7 == 0x400)) + return; + + printk(KERN_DEFAULT "DR0: %016lx DR1: %016lx DR2: %016lx\n", d0, d1, d2); printk(KERN_DEFAULT "DR3: %016lx DR6: %016lx DR7: %016lx\n", d3, d6, d7); + } void release_thread(struct task_struct *dead_task) diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index 7305f7d..5905dc5 100644 --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -110,11 +110,16 @@ void __show_regs(struct pt_regs *regs, int all) get_debugreg(d1, 1); get_debugreg(d2, 2); get_debugreg(d3, 3); - printk(KERN_DEFAULT "DR0: %08lx DR1: %08lx DR2: %08lx DR3: %08lx\n", - d0, d1, d2, d3); - get_debugreg(d6, 6); get_debugreg(d7, 7); + + /* Only print out debug registers if they are in their non-default state. */ + if ((d0 == 0) && (d1 == 0) && (d2 == 0) && (d3 == 0) && + (d6 & ~DR6_RESERVED) && (d7 == 0x400)) + return; + + printk(KERN_DEFAULT "DR0: %08lx DR1: %08lx DR2: %08lx DR3: %08lx\n", + d0, d1, d2, d3); printk(KERN_DEFAULT "DR6: %08lx DR7: %08lx\n", d6, d7); } -- 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/