Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755209Ab0LANYs (ORCPT ); Wed, 1 Dec 2010 08:24:48 -0500 Received: from mail-ey0-f174.google.com ([209.85.215.174]:52443 "EHLO mail-ey0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754182Ab0LANYr convert rfc822-to-8bit (ORCPT ); Wed, 1 Dec 2010 08:24:47 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type:content-transfer-encoding; b=qaBvQNOxuaPELQjIra8jnfBAloXDBlJmfnKADfVAvbV4xDkbiy6iFfRDa+twJdme+6 dW/4fMB28wd/joqp393yVWIDVn5Xh+np8310G9NMwU6Rz601MIXsCDIqrlrtbEzCBF2x QT3Pt8chbM6uXpxGuFhc8txQoWpa/1Wf5XbUA= MIME-Version: 1.0 In-Reply-To: References: <20101129081619.GD5218@cr0.nay.redhat.com> <4CF36741.9000808@loongson.cn> <4CF3762B.9010102@loongson.cn> From: Hui Zhu Date: Wed, 1 Dec 2010 21:24:25 +0800 Message-ID: Subject: Re: [hellogcc] Re: [PATCH] Built kernel without -O2 option To: hellogcc@freelists.org Cc: =?ISO-8859-1?Q?Am=E9rico_Wang?= , linux-kernel@vger.kernel.org, gdb@sourceware.org Content-Type: text/plain; charset=GB2312 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4637 Lines: 161 2.6.35.4 is a little old. What I try is 2.6.37-rc3+ and 2.6.37-rc4+ amd64 and i386. Thanks, Hui 2010/12/1 bekars : > ???????????У?????2.6.35.4?Úº??ϱ??룬???í£º > > ./mm.sh -Wp,-MD,arch/x86/kernel/.entry_32.o.d -nostdinc -isystem > /usr/lib/gcc/i486-linux-gnu/4.3.2/include > -I/home/baiyu/Melon/RSW3/base_system/linux.DEV/LKGDB/arch/x86/include > -Iinclude -include include/generated/autoconf.h -D__KERNEL__ > -D__ASSEMBLY__ -m32 -DCONFIG_AS_CFI=1 -DCONFIG_AS_CFI_SIGNAL_FRAME=1 > -DCONFIG_AS_CFI_SECTIONS=1 -gdwarf-2 -c -o > arch/x86/kernel/entry_32.o arch/x86/kernel/entry_32.S > /home/baiyu/Melon/RSW3/base_system/linux.DEV/LKGDB/arch/x86/include/asm/dwarf2.h: > Assembler messages: > /home/baiyu/Melon/RSW3/base_system/linux.DEV/LKGDB/arch/x86/include/asm/dwarf2.h:46: > Error: unknown pseudo-op: `.cfi_sections' > /home/baiyu/Melon/RSW3/base_system/linux.DEV/LKGDB/arch/x86/include/asm/dwarf2.h: > Assembler messages: > /home/baiyu/Melon/RSW3/base_system/linux.DEV/LKGDB/arch/x86/include/asm/dwarf2.h:46: > Error: unknown pseudo-op: `.cfi_sections' > /home/baiyu/Melon/RSW3/base_system/linux.DEV/LKGDB/arch/x86/include/asm/dwarf2.h: > Assembler messages: > /home/baiyu/Melon/RSW3/base_system/linux.DEV/LKGDB/arch/x86/include/asm/dwarf2.h:46: > Error: unknown pseudo-op: `.cfi_sections' > make[2]: *** [arch/x86/kernel/entry_32.o] Error 1 > make[1]: *** [arch/x86/kernel] Error 2 > make: *** [arch/x86] Error 2 > > > > ?? 2010??11??29?? ????5:45???dz? д???? >> Hui Zhu д??: >>> In this way, you will got a lot of error. >>> >>> Hui >>> >>> On Mon, Nov 29, 2010 at 16:41, ?dz? wrote: >>> >>>> does not need change kernel,just write a shell mycc as bellow: >>>> >>>> #!/bin/sh >>>> gcc "$@" -O0 >>>> >>>> >> change mycc to this will work,:) >> >> #!/bin/sh >> gcc "$@" -O0 || >> gcc "$@" -O1 || >> gcc "$@" >> >> >>>> then >>>> >>>> make CC=./mycc vmlinux >>>> >>>> Hui Zhu said >>>> >>>> On Mon, Nov 29, 2010 at 16:16, Am??rico Wang >>>> wrote: >>>> >>>> >>>> On Mon, Nov 29, 2010 at 11:56:15AM +0800, Hui Zhu wrote: >>>> >>>> >>>> Hi, >>>> >>>> Now, there are a lot of ways to debug the Linux kernel with GDB, like >>>> qemu, kgtp or kgdb and so on. >>>> But the developer more like add a printk. It have a lot of reason, a big one >>>> is: >>>> (gdb) p ret >>>> $3 = >>>> And the code execution order is not right. >>>> >>>> This is becuase the Kernel is bult with gcc -O2. Gcc will not >>>> generate enough debug message with file with -O2. >>>> So GDB cannot work very well with Linux kernel. >>>> >>>> So I make a patch that add a option in "Kernel hacking" called "Close >>>> GCC optimization". It will make kernel be built without -O2. >>>> >>>> I built and use it in i386 and x86_64. I will try to make it OK in other >>>> arch. >>>> >>>> >>>> >>>> The problem is that some functions _have to_ be inlined and gcc without -O2 >>>> doesn't inline them. Have check all the cases? I doubt. >>>> >>>> >>>> If they really need O2, I set them to O2. >>>> Actually, this is the main work, find out the file that need the O2. :) >>>> >>>> For example: >>>> ifdef CONFIG_CC_CLOSE_OPTIMIZATION >>>> CFLAGS_fpu.o += -O2 >>>> CFLAGS_aesni-intel_glue.o += -O2 >>>> CFLAGS_ghash-clmulni-intel_glue.o += -O2 >>>> endif >>>> >>>> And I will try to find more of these type files. >>>> >>>> >>>> >>>> Also, what is size of vmlinux before applying your patch and after that? >>>> Does it increase too much? >>>> >>>> >>>> >>>> Before the patch: >>>> ls -alh vmlinuz-2.6.37-rc3+ >>>> -rw-r--r-- 1 root root 4.1M 2010-11-25 12:02 vmlinuz-2.6.37-rc3+ >>>> ls -alh b26no/vmlinux >>>> -rwxr-xr-x 1 teawater teawater 135M 2010-11-25 13:31 b26no/vmlinux >>>> >>>> After the patch: >>>> ls -alh vmlinuz-2.6.37-rc3debug+ >>>> -rw-r--r-- 1 root root 4.6M 2010-11-25 14:02 vmlinuz-2.6.37-rc3debug+ >>>> ls -alh b26/vmlinux >>>> -rwxr-xr-x 1 teawater teawater 140M 2010-11-25 11:14 b26/vmlinux >>>> >>>> Thanks, >>>> Hui >>>> >>>> >>>> >>>> >>>> -- >>>> >>>> ?dz? qiaochong@loongson.cn >>>> >>>> 2010?? 11?? 29?? ????Ò» 16:35:38 CST >>>> >>> >>> >>> >> >> >> -- >> >> ?dz? qiaochong@loongson.cn >> ??о?пƼ??????????????Þ¹?˾ >> office:010-62600855-615 >> mobile:13521990614 >> >> 2010?? 11?? 29?? ????Ò» 17:38:14 CST >> >> > > -- 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/