Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754999Ab0LAN6o (ORCPT ); Wed, 1 Dec 2010 08:58:44 -0500 Received: from mail-qy0-f181.google.com ([209.85.216.181]:43218 "EHLO mail-qy0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754182Ab0LAN6n convert rfc822-to-8bit (ORCPT ); Wed, 1 Dec 2010 08:58:43 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=nhU0VE49/ffmz3K6KuvlhHpofyvHyVZZmAgYkGi7mQfLT9TvdCs+UIc8iSVWKPHbtO 19fboheP7Ve1WTlnSf6g2f2WnCeC8aAwT8K9oEelUh0FkdHrbnB0gKljWZObPFQ/NJNu dpDpKEBPYUbgAVnS77VqzWfKRoB3MduEevdOc= MIME-Version: 1.0 In-Reply-To: References: <20101129081619.GD5218@cr0.nay.redhat.com> <4CF36741.9000808@loongson.cn> <4CF3762B.9010102@loongson.cn> Date: Wed, 1 Dec 2010 21:58:42 +0800 Message-ID: Subject: Re: [hellogcc] Re: [PATCH] Built kernel without -O2 option From: bekars 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: 5282 Lines: 183 ??ʵ?????? >>> #!/bin/sh >>> gcc "$@" -O0 || >>> gcc "$@" -O1 || >>> gcc "$@" >>> >>> >>>>> then >>>>> >>>>> make CC=./mycc vmlinux ???????????о?????Щ?????DZ??ë²»????????patch?????????Ô¡? ??Òª????????ϵͳ???????Þ¸???net/Makefile??????KBUILD_CFLAGS += -O0??????Ö®?????????ںˣ?????Ò»??????ͨ?ž?panic?Ë£??ں˶?????Makefile???õ???-O1?Å»?Ñ¡?? ?????Dz???Ò»??????-O0??Ò»??????-O2??-O1?????????????ں˻᲻?ȶ??? ?? 2010??12??1?? ????9:24??Hui Zhu д???? > 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/