From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 11451 invoked by alias); 29 Nov 2010 08:18:38 -0000 Received: (qmail 11441 invoked by uid 22791); 29 Nov 2010 08:18:37 -0000 X-SWARE-Spam-Status: No, hits=-0.8 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,FREEMAIL_FROM,MISSING_HEADERS,RCVD_IN_DNSWL_NONE,TW_KG,T_TO_NO_BRKTS_FREEMAIL X-Spam-Check-By: sourceware.org Received: from mail-qw0-f41.google.com (HELO mail-qw0-f41.google.com) (209.85.216.41) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Mon, 29 Nov 2010 08:18:32 +0000 Received: by qwi2 with SMTP id 2so1278263qwi.0 for ; Mon, 29 Nov 2010 00:18:30 -0800 (PST) Received: by 10.224.2.71 with SMTP id 7mt6606572qai.4.1291018709504; Mon, 29 Nov 2010 00:18:29 -0800 (PST) MIME-Version: 1.0 Received: by 10.220.122.37 with HTTP; Mon, 29 Nov 2010 00:18:09 -0800 (PST) In-Reply-To: <20101129081619.GD5218@cr0.nay.redhat.com> References: <20101129081619.GD5218@cr0.nay.redhat.com> From: microcai Date: Mon, 29 Nov 2010 08:18:00 -0000 Message-ID: Subject: Re: [PATCH] Built kernel without -O2 option Cc: Hui Zhu , linux-kernel@vger.kernel.org, gdb@sourceware.org, hellogcc@freelists.org Content-Type: text/plain; charset=UTF-8 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: 2010-11/txt/msg00106.txt.bz2 2010/11/29 Am=C3=A9rico Wang : > 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. =C2=A0Gcc 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". =C2=A0It will make kernel be built without -O2. >> >>I built and use it in i386 and x86_64. =C2=A0I 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. > > Also, what is size of vmlinux before applying your patch and after that? > Does it increase too much? > -- > 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 =C2=A0http://vger.kernel.org/majordomo-info.html > Please read the FAQ at =C2=A0http://www.tux.org/lkml/ >