From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 14510 invoked by alias); 1 Dec 2010 15:02:28 -0000 Received: (qmail 14497 invoked by uid 22791); 1 Dec 2010 15:02:25 -0000 X-SWARE-Spam-Status: No, hits=0.7 required=5.0 tests=AWL,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-ey0-f169.google.com (HELO mail-ey0-f169.google.com) (209.85.215.169) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Wed, 01 Dec 2010 15:02:20 +0000 Received: by eydd26 with SMTP id d26so17182425eyd.0 for ; Wed, 01 Dec 2010 07:02:17 -0800 (PST) Received: by 10.216.18.71 with SMTP id k49mr7684580wek.67.1291215736961; Wed, 01 Dec 2010 07:02:16 -0800 (PST) MIME-Version: 1.0 Received: by 10.216.186.148 with HTTP; Wed, 1 Dec 2010 07:01:56 -0800 (PST) In-Reply-To: References: <20101129081619.GD5218@cr0.nay.redhat.com> <4CF36741.9000808@loongson.cn> <4CF3762B.9010102@loongson.cn> From: Hui Zhu Date: Wed, 01 Dec 2010 15:02:00 -0000 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: quoted-printable X-IsSubscribed: yes 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/msg00011.txt.bz2 2010/12/1 bekars : > =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 > > I think is because some function without -O2 will need a lot of stack (I got some warning about it when I built). Call this function will make kernel stack overflow. So I add some function to -O2 and increase the stack size of amd64. +#ifdef CONFIG_CC_CLOSE_OPTIMIZATION +#define THREAD_ORDER 2 +#else #define THREAD_ORDER 1 +#endif #define THREAD_SIZE (PAGE_SIZE << THREAD_ORDER) #define CURRENT_MASK (~(THREAD_SIZE - 1)) Thanks, Hui > =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 w= rote: >>>>> >>>>>> 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 = other >>>>>> arch. >>>>>> >>>>>> >>>>>> >>>>>> The problem is that some functions _have to_ be inlined and gcc with= out -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 t= hat? >>>>>> 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 >>>> >>>> >>> >>> >> >> > >