From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 48F63C4167B for ; Tue, 8 Dec 2020 09:22:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 09DF623A81 for ; Tue, 8 Dec 2020 09:22:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728738AbgLHJVv (ORCPT ); Tue, 8 Dec 2020 04:21:51 -0500 Received: from m9785.mail.qiye.163.com ([220.181.97.85]:8979 "EHLO m9785.mail.qiye.163.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726114AbgLHJVu (ORCPT ); Tue, 8 Dec 2020 04:21:50 -0500 Received: from localhost (unknown [117.48.120.186]) by m9785.mail.qiye.163.com (Hmail) with ESMTPA id 779595C1D0C; Tue, 8 Dec 2020 17:20:38 +0800 (CST) Date: Tue, 8 Dec 2020 17:20:35 +0800 From: WANG Chao To: Masahiro Yamada Cc: Linux Kernel Mailing List , Linux Kbuild mailing list , artem.savkov@gmail.com, joe.lawrence@redhat.com Subject: Re: [PATCH] kbuild: add extra-y to targets-for-modules Message-ID: <20201208092035.GA96434@MacBook-Pro-2.local> References: <20201103054425.59251-1-chao.wang@ucloud.cn> <20201123150452.GA68187@MacBook-Pro-2> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-HM-Spam-Status: e1kfGhgUHx5ZQUtXWQgYFAkeWUFZS1VLWVdZKFlBSUI3V1ktWUFJV1kPCR oVCBIfWUFZSEgdHk8aTEMYH0lPVkpNS0xPSkJJSENNTk9VGRETFhoSFyQUDg9ZV1kWGg8SFR0UWU FZT0tIVUpKS09ISVVLWQY+ X-HM-Sender-Digest: e1kMHhlZQR0aFwgeV1kSHx4VD1lBWUc6PSo6Tjo5Cj04Nio3C1YqGi0W NzkKChxVSlVKTUtMT0pCSUhDQ0hMVTMWGhIXVRgTGhRVDBoVHDsOGBcUDh9VGBVFWVdZEgtZQVlK SkxVT0NVSklLVUpDTVlXWQgBWUFPQkJDNwY+ X-HM-Tid: 0a7641a7188e2087kuqy779595c1d0c Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Sorry for the late reply. On 11/25/20 at 10:42P, Masahiro Yamada wrote: > On Tue, Nov 24, 2020 at 12:05 AM WANG Chao wrote: > > > > On 11/23/20 at 02:23P, Masahiro Yamada wrote: > > > On Tue, Nov 3, 2020 at 3:23 PM WANG Chao wrote: > > > > > > > > extra-y target doesn't build for 'make M=...' since commit 6212804f2d78 > > > > ("kbuild: do not create built-in objects for external module builds"). > > > > > > > > This especially breaks kpatch, which is using 'extra-y := kpatch.lds' > > > > and 'make M=...' to build livepatch patch module. > > > > > > > > Add extra-y to targets-for-modules so that such kind of build works > > > > properly. > > > > > > > > Signed-off-by: WANG Chao > > > > --- > > > > scripts/Makefile.build | 2 +- > > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > > > diff --git a/scripts/Makefile.build b/scripts/Makefile.build > > > > index ae647379b579..0113a042d643 100644 > > > > --- a/scripts/Makefile.build > > > > +++ b/scripts/Makefile.build > > > > @@ -86,7 +86,7 @@ ifdef need-builtin > > > > targets-for-builtin += $(obj)/built-in.a > > > > endif > > > > > > > > -targets-for-modules := $(patsubst %.o, %.mod, $(filter %.o, $(obj-m))) > > > > +targets-for-modules := $(extra-y) $(patsubst %.o, %.mod, $(filter %.o, $(obj-m))) > > > > > > > > ifdef need-modorder > > > > targets-for-modules += $(obj)/modules.order > > > > -- > > > > 2.29.1 > > > > > > > > > > NACK. > > > > > > Please fix your Makefile. > > > > > > Hint: > > > https://patchwork.kernel.org/project/linux-kbuild/patch/20201123045403.63402-6-masahiroy@kernel.org/ > > > > > > > > > Probably what you should use is 'targets'. > > > > I tried with 'targets' and 'always-y'. Both doesn't work for me. > > > > I narraw it down to the following example: > > > > cat > Makefile << _EOF_ > > obj-m += foo.o > > > > ldflags-y += -T $(src)/kpatch.lds > > always-y += kpatch.lds > > > > foo-objs += bar.o > > > > all: > > make -C /lib/modules/$(shell uname -r)/build M=$(PWD) > > clean: > > make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean > > _EOF_ > > > > Take a look into scripts/Makefile.build:488: > > > > __build: $(if $(KBUILD_BUILTIN), $(targets-for-builtin)) \ > > $(if $(KBUILD_MODULES), $(targets-for-modules)) \ > > $(subdir-ym) $(always-y) > > @: > > > > 'always-y' is built after 'targets-for-modules'. This makes > > 'targets-for-modules' fails because kpatch.lds isn't there. > > > Heh, you rely on the targets built from left to right, > and you have never thought Make supports the parallel option -j. You're right. I missed that. > > > You need to specify the dependency if you expect objects > are built in the particular order. > > However, in this case, using ldflags-y looks wrong > in the first place. > > The linker script is used when combining the object > as well as the final link of *.ko I don't have a clean fix to kpatch right now. I'm looping kpatch forks in. They're also looking at this right now: https://github.com/dynup/kpatch/pull/1149 Thanks WANG Chao > > > > For 'targets', in case of OOT, does not seem to be useful. > > > > What change do you suggest to make to fix this kind of Makefile? > > > > Thanks, > > WANG Chao > > > > -- > Best Regards > Masahiro Yamada >