From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Fri, 30 Mar 2007 15:50:56 +0100 (BST) Received: from webmail.ict.ac.cn ([159.226.39.7]:30851 "EHLO ict.ac.cn") by ftp.linux-mips.org with ESMTP id S20021376AbXC3Ouu (ORCPT ); Fri, 30 Mar 2007 15:50:50 +0100 Received: (qmail 18329 invoked by uid 507); 30 Mar 2007 22:50:08 +0800 Received: from unknown (HELO ?192.168.1.3?) (fxzhang@210.77.15.146) by ict.ac.cn with SMTP; 30 Mar 2007 22:50:08 +0800 Message-ID: <460D2602.6060003@ict.ac.cn> Date: Fri, 30 Mar 2007 23:00:18 +0800 From: Fuxin Zhang User-Agent: Icedove 1.5.0.8 (X11/20061116) MIME-Version: 1.0 To: linux-mips@linux-mips.org Subject: kbuild O= support broken? Content-Type: text/plain; charset=GB18030; format=flowed Content-Transfer-Encoding: 7bit Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 14780 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: fxzhang@ict.ac.cn Precedence: bulk X-list: linux-mips Hello, Recently I meet a strange error when building a kernel: if I build the kernel in the source tree, then it will work well; but if I build it with O=../build, then the resulting kernel is unstable. Looking into the problem, I find that these two kernel is quite different, e.g. ls -l */built-in.o in build/ dir: -rw-r--r-- 1 loongson loongson 155239 2007-03-30 10:21 block/built-in.o -rw-r--r-- 1 loongson loongson 18923 2007-03-30 10:20 crypto/built-in.o -rw-r--r-- 1 loongson loongson 1498144 2007-03-30 10:30 drivers/built-in.o -rw-r--r-- 1 loongson loongson 1075678 2007-03-30 10:20 fs/built-in.o -rw-r--r-- 1 loongson loongson 48747 2007-03-30 22:24 init/built-in.o -rw-r--r-- 1 loongson loongson 38110 2007-03-30 10:20 ipc/built-in.o -rw-r--r-- 1 loongson loongson 468469 2007-03-30 10:18 kernel/built-in.o -rw-r--r-- 1 loongson loongson 18898 2007-03-30 10:41 lib/built-in.o -rw-r--r-- 1 loongson loongson 313511 2007-03-30 10:12 mm/built-in.o -rw-r--r-- 1 loongson loongson 974689 2007-03-30 10:40 net/built-in.o -rw-r--r-- 1 loongson loongson 6774 2007-03-30 10:20 security/built-in.o -rw-r--r-- 1 loongson loongson 8 2007-03-30 22:43 sound/built-in.o -rw-r--r-- 1 loongson loongson 913 2007-03-30 10:07 usr/built-in.o ls -l */built-in.o in src tree: -rw-r--r-- 1 loongson loongson 155484 2007-03-29 23:03 block/built-in.o -rw-r--r-- 1 loongson loongson 21702 2007-03-29 23:01 crypto/built-in.o -rw-r--r-- 1 loongson loongson 1771957 2007-03-29 23:26 drivers/built-in.o -rw-r--r-- 1 loongson loongson 1087193 2007-03-29 23:00 fs/built-in.o -rw-r--r-- 1 loongson loongson 48747 2007-03-30 22:21 init/built-in.o -rw-r--r-- 1 loongson loongson 54546 2007-03-29 23:01 ipc/built-in.o -rw-r--r-- 1 loongson loongson 470917 2007-03-30 10:16 kernel/built-in.o -rw-r--r-- 1 loongson loongson 23356 2007-03-29 23:51 lib/built-in.o -rw-r--r-- 1 loongson loongson 314543 2007-03-29 22:30 mm/built-in.o -rw-r--r-- 1 loongson loongson 935894 2007-03-29 23:50 net/built-in.o -rw-r--r-- 1 loongson loongson 6774 2007-03-29 23:01 security/built-in.o -rw-r--r-- 1 loongson loongson 12154 2007-03-30 22:21 sound/built-in.o -rw-r--r-- 1 loongson loongson 894 2007-03-29 22:20 usr/built-in.o loongson@debian:~/old$ ls -l vmlinux ../build-old/vmlinux -rwxr-xr-x 1 loongson loongson 3856719 2007-03-30 22:24 ../build-old/vmlinux -rwxr-xr-x 1 loongson loongson 4079730 2007-03-30 22:21 vmlinux the size different is around 200K! Take the "sound" subdir for example, I use Make V=1 to check the output and find that while in the src tree, obj-y is correctly set to soundcore.o, so built-in.o will be linked using: (CONFIG_SOUND=y) make -f scripts/Makefile.build obj=sound ld -m elf32ltsmip -r -o sound/built-in.o sound/soundcore.o while with O= option: make -f /home/loongson/old/scripts/Makefile.build obj=sound rm -f sound/built-in.o; ar rcs sound/built-in.o check scripts/Makefile.build we can find that it indicates that obj-y is null: around line 260: ifdef builtin-target quiet_cmd_link_o_target = LD $@ # If the list of objects to link is empty, just create an empty built-in.o cmd_link_o_target = $(if $(strip $(obj-y)),\ $(LD) $(ld_flags) -r -o $@ $(filter $(obj-y), $^),\ rm -f $@; $(AR) rcs $@) $(builtin-target): $(obj-y) FORCE $(call if_changed,link_o_target) Anybody can help explain this? Thank you. yours Fuxin Zhang