From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 15620 invoked by alias); 1 Dec 2010 13:58:53 -0000 Received: (qmail 15592 invoked by uid 22791); 1 Dec 2010 13:58:50 -0000 X-SWARE-Spam-Status: No, hits=2.9 required=5.0 tests=BAYES_50,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,MIME_CHARSET_FARAWAY,RCVD_IN_DNSWL_LOW,TW_CL,TW_GD,TW_KG,TW_RW,TW_WX,T_FRT_BELOW2,T_TO_NO_BRKTS_FREEMAIL X-Spam-Check-By: sourceware.org Received: from mail-qy0-f169.google.com (HELO mail-qy0-f169.google.com) (209.85.216.169) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Wed, 01 Dec 2010 13:58:44 +0000 Received: by qyk7 with SMTP id 7so2543626qyk.0 for ; Wed, 01 Dec 2010 05:58:42 -0800 (PST) MIME-Version: 1.0 Received: by 10.224.181.140 with SMTP id by12mr5954775qab.39.1291211922728; Wed, 01 Dec 2010 05:58:42 -0800 (PST) Received: by 10.220.60.10 with HTTP; Wed, 1 Dec 2010 05:58:42 -0800 (PST) In-Reply-To: References: <20101129081619.GD5218@cr0.nay.redhat.com> <4CF36741.9000808@loongson.cn> <4CF3762B.9010102@loongson.cn> Date: Wed, 01 Dec 2010 13:58:00 -0000 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: quoted-printable Mailing-List: contact gdb-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-owner@sourceware.org X-SW-Source: 2010-12/txt/msg00010.txt.bz2 =CE=D2=CA=B5=D1=E9=B5=C4=CA=C7 >>> #!/bin/sh >>> gcc "$@" -O0 || >>> gcc "$@" -O1 || >>> gcc "$@" >>> >>> >>>>> then >>>>> >>>>> make CC=3D./mycc vmlinux =D5=E2=B8=F6=B7=BD=B7=A8=A3=AC=B8=D0=BE=F5=BC=F2=B5=A5=D0=A9=A3=AC=B5=AB=CA= =C7=B1=E0=D2=EB=B2=BB=B9=FD=A3=AC=C4=E3=B5=C4patch=CE=D2=C3=F7=CC=EC=CA=D4= =CA=D4=A1=A3 =CE=D2=D2=AA=B5=F7=CA=D4=CD=F8=C2=E7=CF=B5=CD=B3=A3=AC=D3=DA=CA=C7=D0=DE=B8= =C4=C1=CBnet/Makefile=A3=AC=BC=D3=C9=CFKBUILD_CFLAGS +=3D -O0=A3=AC=B1=E0=D2=EB=D6=AE=BA=F3=C4=DC=C6=F4=B6=AF=C4=DA=BA=CB=A3=AC=B5=AB= =CA=C7=D2=BB=D3=D0=CD=F8=C2=E7=CD=A8=D0=C5=BE=CDpanic=C1=CB=A3=AC=C4=DA=BA= =CB=B6=A5=B2=E3=B5=C4Makefile=CE=D2=D3=C3=B5=C4=CA=C7-O1=D3=C5=BB=AF=D1=A1= =CF=EE =C7=EB=CE=CA=CA=C7=B2=BB=CA=C7=D2=BB=B2=BF=B7=D6=D3=C3-O0=A3=AC=D2=BB=B2=BF= =B7=D6=D3=C3-O2=BB=F2-O1=A3=AC=B1=E0=D2=EB=B3=F6=C0=B4=B5=C4=C4=DA=BA=CB=BB= =E1=B2=BB=CE=C8=B6=A8=A3=BF =D4=DA 2010=C4=EA12=D4=C21=C8=D5 =CF=C2=CE=E79:24=A3=ACHui Zhu =D0=B4=B5=C0=A3=BA > 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 : >> =D5=E2=B8=F6=BA=C3=CF=F1=B2=BB=D0=D0=A3=AC=CE=D2=D4=DA2.6.35.4=C4=DA=BA= =CB=C9=CF=B1=E0=D2=EB=A3=AC=B1=A8=B4=ED=A3=BA >> >> ./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=3D1 -DCONFIG_AS_CFI_SIGNAL_FRAME=3D1 >> -DCONFIG_AS_CFI_SECTIONS=3D1 -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 >> >> >> >> =D4=DA 2010=C4=EA11=D4=C229=C8=D5 =CF=C2=CE=E75:45=A3=AC=C7=C7=B3=E7 =D0=B4=B5=C0=A3=BA >>> Hui Zhu =D0=B4=B5=C0: >>>> In this way, you will got a lot of error. >>>> >>>> Hui >>>> >>>> On Mon, Nov 29, 2010 at 16:41, =C7=C7=B3=E7 wr= ote: >>>> >>>>> 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=3D./mycc vmlinux >>>>> >>>>> Hui Zhu said >>>>> >>>>> On Mon, Nov 29, 2010 at 16:16, Am=A8=A6rico 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 =3D >>>>> 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 o= ther >>>>> arch. >>>>> >>>>> >>>>> >>>>> The problem is that some functions _have to_ be inlined and gcc witho= ut -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 +=3D -O2 >>>>> CFLAGS_aesni-intel_glue.o +=3D -O2 >>>>> CFLAGS_ghash-clmulni-intel_glue.o +=3D -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 th= at? >>>>> 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 >>>>> >>>>> >>>>> >>>>> >>>>> -- >>>>> >>>>> =C7=C7=B3=E7 qiaochong@loongson.cn >>>>> >>>>> 2010=C4=EA 11=D4=C2 29=C8=D5 =D0=C7=C6=DA=D2=BB 16:35:38 CST >>>>> >>>> >>>> >>>> >>> >>> >>> -- >>> >>> =C7=C7=B3=E7 qiaochong@loongson.cn >>> =C1=FA=D0=BE=D6=D0=BF=C6=BC=BC=CA=F5=B7=FE=CE=F1=D6=D0=D0=C4=D3=D0=CF= =DE=B9=AB=CB=BE >>> office:010-62600855-615 >>> mobile:13521990614 >>> >>> 2010=C4=EA 11=D4=C2 29=C8=D5 =D0=C7=C6=DA=D2=BB 17:38:14 CST >>> >>> >> >> > >