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=-17.0 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 CA737C432BE for ; Thu, 19 Aug 2021 00:59:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B2E1E608FE for ; Thu, 19 Aug 2021 00:59:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235428AbhHSBAH (ORCPT ); Wed, 18 Aug 2021 21:00:07 -0400 Received: from conuserg-10.nifty.com ([210.131.2.77]:60782 "EHLO conuserg-10.nifty.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235481AbhHSA7a (ORCPT ); Wed, 18 Aug 2021 20:59:30 -0400 Received: from localhost.localdomain (133-32-232-101.west.xps.vectant.ne.jp [133.32.232.101]) (authenticated) by conuserg-10.nifty.com with ESMTP id 17J0vl4t017219; Thu, 19 Aug 2021 09:57:53 +0900 DKIM-Filter: OpenDKIM Filter v2.10.3 conuserg-10.nifty.com 17J0vl4t017219 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com; s=dec2015msa; t=1629334674; bh=HwNkxravsiti3cPH3/pynEvNeo61f93j4rWZZTlauzs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RGZjPaYIKwKIyLm6dCKZjGG2fGlheiZ51fRWPfHlR0Kc2jtVXVlebgOm17a9ZEiBc kjcYbXl3lAOOH0IDTG08kyxISsgouZuE60grXZgwIaNGanArt6EFakiQaLAHpiwwe2 dZk3wOrNH9kZX4nDyCDs4dXodN7zA7iCUtmd9uxoID8B6MnLFq1TjtaL08n11lmh9d v9sZBmz4Vot3JSzz+6aSShvNyM+41LNQDt7JGl/KpJKEfqfWtQBSrm9Fcy8aDChWtH HCNwf9Tr/OSbKsTFzlNpUBgmNnzXDY+GloS4FT5t8DLa/hV3HQY+T7bQr/oBBerN5w 5dw83MvIzHt/A== X-Nifty-SrcIP: [133.32.232.101] From: Masahiro Yamada To: linux-kbuild@vger.kernel.org Cc: Sami Tolvanen , linux-kernel@vger.kernel.org, Masahiro Yamada , Michal Marek , Nathan Chancellor , Nick Desaulniers , clang-built-linux@googlegroups.com Subject: [PATCH 10/13] kbuild: build modules in the same way with/without Clang LTO Date: Thu, 19 Aug 2021 09:57:41 +0900 Message-Id: <20210819005744.644908-11-masahiroy@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210819005744.644908-1-masahiroy@kernel.org> References: <20210819005744.644908-1-masahiroy@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When Clang LTO is enabled, additional intermediate files *.lto.o are created because LLVM bitcode must be converted to ELF before modpost. For non-LTO builds: $(LD) $(LD) objects ---> .o -----> .ko | .mod.o ---/ For Clang LTO builds: $(AR) $(LD) $(LD) objects ---> .o ---> .lto.o -----> .ko | .mod.o --/ Since the Clang LTO introduction, ugly CONFIG_LTO_CLANG conditionals are sprinkled everywhere in the kbuild code. Another confusion for Clang LTO builds is, .o is an archive that contains LLVM bitcode files. The suffix should have been .a instead of .o To clean up the code, unify the build process of modules, as follows: $(AR) $(LD) $(LD) objects ---> .a ---> .prelink.o -----> .ko | .mod.o ------/ Here, 'objects' are either ELF or LLVM bitcode. .a is an archive, .prelink.o is ELF. Signed-off-by: Masahiro Yamada --- scripts/Makefile.build | 103 ++++++++++++++++++-------------------- scripts/Makefile.lib | 11 ++-- scripts/Makefile.modfinal | 4 +- scripts/Makefile.modpost | 7 +-- scripts/mod/modpost.c | 6 +-- scripts/mod/sumversion.c | 6 +-- 6 files changed, 61 insertions(+), 76 deletions(-) diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 37d6f6da34d6..957addea830b 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -88,9 +88,7 @@ endif targets-for-modules := $(patsubst %.o, %.mod, $(filter %.o, $(obj-m))) -ifdef CONFIG_LTO_CLANG -targets-for-modules += $(patsubst %.o, %.lto.o, $(filter %.o, $(obj-m))) -endif +targets-for-modules += $(patsubst %.o, %.prelink.o, $(filter %.o, $(obj-m))) ifdef need-modorder targets-for-modules += $(obj)/modules.order @@ -282,33 +280,12 @@ $(obj)/%.o: $(src)/%.c $(recordmcount_source) $(objtool_dep) FORCE $(call if_changed_rule,cc_o_c) $(call cmd,force_checksrc) -ifdef CONFIG_LTO_CLANG -# Module .o files may contain LLVM bitcode, compile them into native code -# before ELF processing -quiet_cmd_cc_lto_link_modules = LTO [M] $@ -cmd_cc_lto_link_modules = \ - $(LD) $(ld_flags) -r -o $@ \ - $(shell [ -s $(@:.lto.o=.o.symversions) ] && \ - echo -T $(@:.lto.o=.o.symversions)) \ - --whole-archive $(filter-out FORCE,$^) - -ifdef CONFIG_STACK_VALIDATION -# objtool was skipped for LLVM bitcode, run it now that we have compiled -# modules into native code -cmd_cc_lto_link_modules += ; \ - $(objtree)/tools/objtool/objtool $(objtool_args) --module $@ -endif - -$(obj)/%.lto.o: $(obj)/%.o FORCE - $(call if_changed,cc_lto_link_modules) -endif - cmd_mod = { \ echo $(if $($*-objs)$($*-y)$($*-m), $(addprefix $(obj)/, $($*-objs) $($*-y) $($*-m)), $(@:.mod=.o)); \ $(undefined_syms) echo; \ } > $@ -$(obj)/%.mod: $(obj)/%$(mod-prelink-ext).o FORCE +$(obj)/%.mod: $(obj)/%.prelink.o FORCE $(call if_changed,mod) quiet_cmd_cc_lst_c = MKLST $@ @@ -412,17 +389,6 @@ $(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler $(subdir-builtin): $(obj)/%/built-in.a: $(obj)/% ; $(subdir-modorder): $(obj)/%/modules.order: $(obj)/% ; -# combine symversions for later processing -ifeq ($(CONFIG_LTO_CLANG) $(CONFIG_MODVERSIONS),y y) - cmd_update_lto_symversions = \ - rm -f $@.symversions \ - $(foreach n, $(filter-out FORCE,$^), \ - $(if $(shell test -s $(n).symversions && echo y), \ - ; cat $(n).symversions >> $@.symversions)) -else - cmd_update_lto_symversions = echo >/dev/null -endif - # # Rule to compile a set of .o files into one .a file (without symbol table) # @@ -442,10 +408,10 @@ $(obj)/built-in.a: $(real-obj-y) FORCE # modules.order unless contained modules are updated. cmd_modules_order = { $(foreach m, $(real-prereqs), \ - $(if $(filter %/modules.order, $m), cat $m, echo $(patsubst %.o,%.ko,$m));) :; } \ + $(if $(filter %/modules.order, $m), cat $m, echo $(patsubst %.a,%.ko,$m));) :; } \ | $(AWK) '!x[$$0]++' - > $@ -$(obj)/modules.order: $(obj-m) FORCE +$(obj)/modules.order: $(modules) FORCE $(call if_changed,modules_order) # @@ -454,26 +420,55 @@ $(obj)/modules.order: $(obj-m) FORCE $(obj)/lib.a: $(lib-y) FORCE $(call if_changed,ar) -# NOTE: -# Do not replace $(filter %.o,^) with $(real-prereqs). When a single object -# module is turned into a multi object module, $^ will contain header file -# dependencies recorded in the .*.cmd file. +# +# Rule to prelink modules +# + +ifeq ($(CONFIG_LTO_CLANG) $(CONFIG_MODVERSIONS),y y) + +cmd_merge_symver = \ + rm -f $@; \ + touch $@; \ + for o in $$($(AR) t $<); do \ + if [ -s $${o}.symversions ]; then \ + cat $${o}.symversions >> $@; \ + fi; \ + done + +$(obj)/%.prelink.symversions: $(obj)/%.a FORCE + $(call if_changed,merge_symver) + +$(obj)/%.prelink.o: ld_flags += --script=$(filter %.symversions,$^) +module-symver = $(obj)/%.prelink.symversions + +endif + +quiet_cmd_ld_o_a = LD [M] $@ + cmd_ld_o_a = $(LD) $(ld_flags) -r -o $@ --whole-archive $< + +$(obj)/%.prelink.o: $(obj)/%.a $(module-symver) FORCE + $(call if_changed,ld_o_a) + ifdef CONFIG_LTO_CLANG -quiet_cmd_link_multi-m = AR [M] $@ -cmd_link_multi-m = \ - $(cmd_update_lto_symversions); \ - rm -f $@; \ - $(AR) cDPrsT $@ $(filter %.o,$^) -else -quiet_cmd_link_multi-m = LD [M] $@ - cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^) +ifdef CONFIG_STACK_VALIDATION +# objtool was skipped for LLVM bitcode, run it now that we have compiled +# modules into native code +cmd_ld_o_a += ; $(objtool) $(objtool_args) --module $@ endif +endif + +quiet_cmd_ar_module = AR [M] $@ + cmd_ar_module = rm -f $@; $(AR) cDPrST $@ $(real-prereqs) + +$(modules-single): %.a: %.o FORCE + $(call if_changed,ar_module) + +$(modules-multi): FORCE + $(call if_changed,ar_module) +$(call multi_depend, $(modules-multi), .a, -objs -y -m) -$(multi-obj-m): FORCE - $(call if_changed,link_multi-m) -$(call multi_depend, $(multi-obj-m), .o, -objs -y -m) +targets += $(modules-single) $(modules-multi) -targets += $(multi-obj-m) targets := $(filter-out $(PHONY), $(targets)) # Add intermediate targets: diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index 34c4c11c4bc1..f604d2d01cad 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -106,6 +106,10 @@ multi-dtb-y := $(addprefix $(obj)/, $(multi-dtb-y)) real-dtb-y := $(addprefix $(obj)/, $(real-dtb-y)) subdir-ym := $(addprefix $(obj)/,$(subdir-ym)) +modules := $(patsubst %.o, %.a, $(obj-m)) +modules-multi := $(patsubst %.o, %.a, $(multi-obj-m)) +modules-single := $(filter-out $(modules-multi), $(filter %.a, $(modules))) + # Finds the multi-part object the current object will be linked into. # If the object belongs to two or more multi-part objects, list them all. modname-multi = $(sort $(foreach m,$(multi-obj-ym),\ @@ -225,13 +229,6 @@ dtc_cpp_flags = -Wp,-MMD,$(depfile).pre.tmp -nostdinc \ $(addprefix -I,$(DTC_INCLUDE)) \ -undef -D__DTS__ -ifeq ($(CONFIG_LTO_CLANG),y) -# With CONFIG_LTO_CLANG, .o files in modules might be LLVM bitcode, so we -# need to run LTO to compile them into native code (.lto.o) before further -# processing. -mod-prelink-ext := .lto -endif - # Useful for describing the dependency of composite objects # Usage: # $(call multi_depend, multi_used_targets, suffix_to_remove, suffix_to_add) diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal index ff805777431c..1b6401f53662 100644 --- a/scripts/Makefile.modfinal +++ b/scripts/Makefile.modfinal @@ -9,7 +9,7 @@ __modfinal: include include/config/auto.conf include $(srctree)/scripts/Kbuild.include -# for c_flags and mod-prelink-ext +# for c_flags include $(srctree)/scripts/Makefile.lib # find all modules listed in modules.order @@ -55,7 +55,7 @@ if_changed_except = $(if $(call newer_prereqs_except,$(2))$(cmd-check), \ # Re-generate module BTFs if either module's .ko or vmlinux changed -$(modules): %.ko: %$(mod-prelink-ext).o %.mod.o scripts/module.lds $(if $(KBUILD_BUILTIN),vmlinux) FORCE +$(modules): %.ko: %.prelink.o %.mod.o scripts/module.lds $(if $(KBUILD_BUILTIN),vmlinux) FORCE +$(call if_changed_except,ld_ko_o,vmlinux) ifdef CONFIG_DEBUG_INFO_BTF_MODULES +$(if $(newer-prereqs),$(call cmd,btf_ko)) diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost index eef56d629799..11883b31c615 100644 --- a/scripts/Makefile.modpost +++ b/scripts/Makefile.modpost @@ -41,9 +41,6 @@ __modpost: include include/config/auto.conf include $(srctree)/scripts/Kbuild.include -# for mod-prelink-ext -include $(srctree)/scripts/Makefile.lib - MODPOST = scripts/mod/modpost \ $(if $(CONFIG_MODVERSIONS),-m) \ $(if $(CONFIG_MODULE_SRCVERSION_ALL),-a) \ @@ -128,9 +125,9 @@ endif # Read out modules.order to pass in modpost. # Otherwise, allmodconfig would fail with "Argument list too long". quiet_cmd_modpost = MODPOST $@ - cmd_modpost = sed 's/\.ko$$/$(mod-prelink-ext)\.o/' $< | $(MODPOST) -T - + cmd_modpost = sed 's/ko$$/prelink.o/' $< | $(MODPOST) -T - -$(output-symdump): $(MODORDER) $(input-symdump) $(modules:.ko=$(mod-prelink-ext).o) FORCE +$(output-symdump): $(MODORDER) $(input-symdump) $(modules:ko=prelink.o) FORCE $(call if_changed,modpost) targets += $(output-symdump) diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 270a7df898e2..8c63c52af88d 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1991,9 +1991,9 @@ static void read_symbols(const char *modname) /* strip trailing .o */ tmp = NOFAIL(strdup(modname)); tmp[strlen(tmp) - 2] = '\0'; - /* strip trailing .lto */ - if (strends(tmp, ".lto")) - tmp[strlen(tmp) - 4] = '\0'; + /* strip trailing .prelink */ + if (strends(tmp, ".prelink")) + tmp[strlen(tmp) - 8] = '\0'; mod = new_module(tmp); free(tmp); } diff --git a/scripts/mod/sumversion.c b/scripts/mod/sumversion.c index 760e6baa7eda..8ea0f7b23c63 100644 --- a/scripts/mod/sumversion.c +++ b/scripts/mod/sumversion.c @@ -391,14 +391,10 @@ void get_src_version(const char *modname, char sum[], unsigned sumlen) struct md4_ctx md; char *fname; char filelist[PATH_MAX + 1]; - int postfix_len = 1; - - if (strends(modname, ".lto.o")) - postfix_len = 5; /* objects for a module are listed in the first line of *.mod file. */ snprintf(filelist, sizeof(filelist), "%.*smod", - (int)strlen(modname) - postfix_len, modname); + (int)(strlen(modname) - strlen("prelink.o")), modname); buf = read_text_file(filelist); -- 2.30.2