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=-7.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 39111C04AAF for ; Tue, 21 May 2019 13:50:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EF20021019 for ; Tue, 21 May 2019 13:50:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nifty.com header.i=@nifty.com header.b="BvauOK+G" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728441AbfEUNuB (ORCPT ); Tue, 21 May 2019 09:50:01 -0400 Received: from conssluserg-02.nifty.com ([210.131.2.81]:58503 "EHLO conssluserg-02.nifty.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728142AbfEUNuA (ORCPT ); Tue, 21 May 2019 09:50:00 -0400 Received: from mail-vs1-f54.google.com (mail-vs1-f54.google.com [209.85.217.54]) (authenticated) by conssluserg-02.nifty.com with ESMTP id x4LDnYw6027273; Tue, 21 May 2019 22:49:35 +0900 DKIM-Filter: OpenDKIM Filter v2.10.3 conssluserg-02.nifty.com x4LDnYw6027273 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com; s=dec2015msa; t=1558446575; bh=wki7JwvrZ9RUz00+Did3BCvqytR4NxGLs+2dqfiy3MM=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=BvauOK+GHa1bl3WAMTDGrf7ni6j8z++/+NkQJOt845euJszQ/Sp+a9udFYjFe7KMM bkrkjmwK99j1jnZuq2JNNyodpy/ts4ayIF9cQo8mnx6gBfzmXONS04r+rSFaHTQZkm tkPn1csNMK5bdlUt7kUl9REGEKhigSKiJeN6wWFWYxV3iIbAD+bS2LcFeMaIRwvw8X 7H4g6lO5nBxNd1fx/O+FPdZTFlHpZgssF598bHBc9LP8HR3kisfeGcktMuTULcPF0B 2vZaaMpeFLANDC2Eh4J6OEy7UZ4SlH+gsCECPDTSkYRGCIWn+9agLNVwKv7uwvBdDN e1RlT3lwtupag== X-Nifty-SrcIP: [209.85.217.54] Received: by mail-vs1-f54.google.com with SMTP id c24so11169656vsp.7; Tue, 21 May 2019 06:49:35 -0700 (PDT) X-Gm-Message-State: APjAAAVDqDGsFTxDXJfmsdYQdmbBJTbsWEI/E49SIDe/Y4ICww8OIdMC Vqfs9z7tFu+TJ0b1+2uOX5yqb6FkHPPwnv1sakc= X-Google-Smtp-Source: APXvYqxcDjZDHiMUpn9cnaLGkfZA35KnjvEwSlFRKKz1fP5fktkPYJE8WDRbS6BEAwZ7dss7nXcKto+7mKSV9eENPpM= X-Received: by 2002:a67:ad0f:: with SMTP id t15mr21995936vsl.179.1558446573967; Tue, 21 May 2019 06:49:33 -0700 (PDT) MIME-Version: 1.0 References: <20190509143859.9050-1-joe.lawrence@redhat.com> <20190509143859.9050-3-joe.lawrence@redhat.com> In-Reply-To: <20190509143859.9050-3-joe.lawrence@redhat.com> From: Masahiro Yamada Date: Tue, 21 May 2019 22:48:57 +0900 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v4 02/10] kbuild: Support for Symbols.list creation To: Joe Lawrence Cc: Linux Kernel Mailing List , live-patching@vger.kernel.org, Linux Kbuild mailing list Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 9, 2019 at 11:40 PM Joe Lawrence wrote: > > From: Joao Moreira > > For automatic resolution of livepatch relocations, a file called > Symbols.list is used. This file maps symbols within every compiled > kernel object allowing the identification of symbols whose name is > unique, thus relocation can be automatically inferred, or providing > information that helps developers when code annotation is required for > solving the matter. > > Add support for creating Symbols.list in the main Makefile. First, > ensure that built-in is compiled when CONFIG_LIVEPATCH is enabled (as > required to achieve a complete Symbols.list file). Define the command to > build Symbols.list (cmd_klp_map) and hook it in the modules rule. > > As it is undesirable to have symbols from livepatch objects inside > Symbols.list, make livepatches discernible by modifying > scripts/Makefile.build to create a .livepatch file for each livepatch > in $(MODVERDIR). This file then used by cmd_klp_map to identify and > bypass livepatches. > > For identifying livepatches during the build process, a flag variable > LIVEPATCH_$(basetarget).o is considered in scripts/Makefile.build. This > way, set this flag for the livepatch sample Makefile in > samples/livepatch/Makefile. > > Finally, Add a clean rule to ensure that Symbols.list is removed during > clean. > > Notes: > > To achieve a correct Symbols.list file, all kernel objects must be > considered, thus, its construction require these objects to be priorly > built. On the other hand, invoking scripts/Makefile.modpost without > having a complete Symbols.list in place would occasionally lead to > in-tree livepatches being post-processed incorrectly. To prevent this > from becoming a circular dependency, the construction of Symbols.list > uses non-post-processed kernel objects and such does not cause harm as > the symbols normally referenced from within livepatches are visible at > this stage. Also due to these requirements, the spot in-between modules > compilation and the invocation of scripts/Makefile.modpost was picked > for hooking cmd_klp_map. > > The approach based on .livepatch files was proposed as an alternative > to using MODULE_INFO statements. This approach was originally > proposed by Miroslav Benes as a workaround for identifying livepathes > without depending on modinfo during the modpost stage. It was moved to > this patch as the approach also shown to be useful while building > Symbols.list. > > Signed-off-by: Joao Moreira > Signed-off-by: Joe Lawrence > --- > .gitignore | 1 + > Makefile | 30 ++++++++++++++++++++++++++---- > lib/livepatch/Makefile | 5 +++++ > samples/livepatch/Makefile | 4 ++++ > scripts/Makefile.build | 7 +++++++ > 5 files changed, 43 insertions(+), 4 deletions(-) > > diff --git a/.gitignore b/.gitignore > index a20ac26aa2f5..5cd5758f5ffe 100644 > --- a/.gitignore > +++ b/.gitignore > @@ -45,6 +45,7 @@ > *.xz > Module.symvers > modules.builtin > +Symbols.list Symbols.list is created only in the top directory. Please move this to # Top-level generic files section with a leading slash. Also, you need to add it to Documentation/dontdiff > # > # Top-level generic files > diff --git a/Makefile b/Makefile > index abe13538a8c0..98089f9d44fe 100644 > --- a/Makefile > +++ b/Makefile > @@ -574,10 +574,13 @@ KBUILD_BUILTIN := 1 > # If we have only "make modules", don't compile built-in objects. > # When we're building modules with modversions, we need to consider > # the built-in objects during the descend as well, in order to > -# make sure the checksums are up to date before we record them. > +# make sure the checksums are up to date before we record them. The > +# same applies for building livepatches, as built-in objects may hold > +# symbols which are referenced from livepatches and are required by > +# klp-convert post-processing tool for resolving these cases. > > ifeq ($(MAKECMDGOALS),modules) > - KBUILD_BUILTIN := $(if $(CONFIG_MODVERSIONS),1) > + KBUILD_BUILTIN := $(if $(or $(CONFIG_MODVERSIONS), $(CONFIG_LIVEPATCH)),1) > endif > > # If we have "make modules", compile modules > @@ -1261,9 +1264,25 @@ all: modules > # duplicate lines in modules.order files. Those are removed > # using awk while concatenating to the final file. > > +quiet_cmd_klp_map = KLP Symbols.list > +SLIST = $(objtree)/Symbols.list Please do not define SLIST. Use Symbols.list directly. > + > +define cmd_klp_map > + $(shell echo "klp-convert-symbol-data.0.1" > $(SLIST)) \ > + $(shell echo "*vmlinux" >> $(SLIST)) \ > + $(shell nm -f posix $(objtree)/vmlinux | cut -d\ -f1 >> $(SLIST)) \ > + $(foreach m, $(wildcard $(MODVERDIR)/*.mod), \ > + $(eval mod = $(patsubst %.ko,%.o,$(shell head -n1 $(m)))) \ > + $(if $(wildcard $(MODVERDIR)/$(shell basename -s .o $(mod)).livepatch),,\ > + $(eval fmod = $(subst $(quote),_,$(subst -,_,$(mod)))) \ > + $(shell echo "*$(shell basename -s .o $(fmod))" >> $(SLIST)) \ > + $(shell nm -f posix $(mod) | cut -d\ -f1 >> $(SLIST)))) > +endef > + > PHONY += modules > modules: $(vmlinux-dirs) $(if $(KBUILD_BUILTIN),vmlinux) modules.builtin > $(Q)$(AWK) '!x[$$0]++' $(vmlinux-dirs:%=$(objtree)/%/modules.order) > $(objtree)/modules.order > + $(if $(CONFIG_LIVEPATCH), $(call cmd,klp_map)) > @$(kecho) ' Building modules, stage 2.'; > $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost > > @@ -1350,7 +1369,7 @@ clean: rm-dirs := $(CLEAN_DIRS) > clean: rm-files := $(CLEAN_FILES) > clean-dirs := $(addprefix _clean_, . $(vmlinux-alldirs) Documentation samples) > > -PHONY += $(clean-dirs) clean archclean vmlinuxclean > +PHONY += $(clean-dirs) clean archclean vmlinuxclean klpclean > $(clean-dirs): > $(Q)$(MAKE) $(clean)=$(patsubst _clean_%,%,$@) > > @@ -1358,7 +1377,10 @@ vmlinuxclean: > $(Q)$(CONFIG_SHELL) $(srctree)/scripts/link-vmlinux.sh clean > $(Q)$(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) clean) > > -clean: archclean vmlinuxclean > +klpclean: > + $(Q) rm -f $(SLIST) klpclean is unneeded. Add it to CLEAN_FILES CLEAN_FILES += modules.builtin.modinfo Systems.list -- Best Regards Masahiro Yamada