From patchwork Tue Sep 29 21:46:14 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sami Tolvanen X-Patchwork-Id: 11807139 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6102F618 for ; Tue, 29 Sep 2020 21:48:46 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 6F8A020774 for ; Tue, 29 Sep 2020 21:48:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="eZ/5sVKn" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6F8A020774 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-20042-patchwork-kernel-hardening=patchwork.kernel.org@lists.openwall.com Received: (qmail 30030 invoked by uid 550); 29 Sep 2020 21:47:12 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 29906 invoked from network); 29 Sep 2020 21:47:11 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:to:cc; bh=tVbCdCSbxCxD3KjIFwFCcvevxc6usIE71x0z99le3Xc=; b=eZ/5sVKnBr6ETXLdCzUKVHkXliivlbESd/B9g8CtynbriyH6DBY5y1NzO83VqIy/h9 zdzoSBE8K0Xh2RtwY2s+GlJSREAPnnlAvBttPZFcHJKTEY+pQfm+ztsZFnHbNpzlJ8BL XEzDaaVJtTF8dQUFmwODKgysmdJ8ssOXw44bbqX2MP6dDtzJMAa9dVLrJihF9AqXb18t tbp6uCl4/7+dA3LQr5BvE5stOIcw7t4ZqclUBGYeg6f0GFzBhBSJNrBSHua55Ij65JHZ IC0O1orcqdobvdY/c53mGX0TFLCmnqLQZtWQFtSZnOCIbqQXW8NoOZYZCz8RNjOx5S2c dy+Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=tVbCdCSbxCxD3KjIFwFCcvevxc6usIE71x0z99le3Xc=; b=TzEsW7E2nAFPYM+zJUdyL6ib7oS+WmObaphcmdAtjkhO7SrSBFtDMxPPoKYbUmg040 L/7v0TOISqqEY31/ApFj8jfNul8ZrE72ZCChI7h4FrilCwFJpVjZjuDUzKYGk5wlO25o O80dUkKZi/zc0dQal4bRLSedsIl9UCQfPOd90t7Tdu/Yl+r6pVOeIvWhqOVPMrChZaXE aiFOenC73g9U8/N+jCB2DlRIh1dHJOd4nFouqkP+ku1De0uvkjJ94Ameo23++zo3gh4Y yQynLLi7MZ6zLmx7umuSPRlIIuam1JjvD6UHbE/ORcTzDOoks/QZLYRflfR10/orodhj eOig== X-Gm-Message-State: AOAM533/2xbWMLts5Xg42mhCGEMCS9tBdOCPu3slkdKlq4aHH7jewve7 6smQpiyS2v7zyxBrGZ5Zyyl6P4XNjwLZAyKeYuY= X-Google-Smtp-Source: ABdhPJy8enqFolbXs8qwfYSILQQkb9ujrLEmxZKfggE9XNXDO7JqswMCtpTbc1qAwa0mZOxpoGgL66PRFsY0rIba6wo= Sender: "samitolvanen via sendgmr" X-Received: from samitolvanen1.mtv.corp.google.com ([2620:15c:201:2:f693:9fff:fef4:1b6d]) (user=samitolvanen job=sendgmr) by 2002:a25:ae4e:: with SMTP id g14mr9182749ybe.156.1601416019420; Tue, 29 Sep 2020 14:46:59 -0700 (PDT) Date: Tue, 29 Sep 2020 14:46:14 -0700 In-Reply-To: <20200929214631.3516445-1-samitolvanen@google.com> Message-Id: <20200929214631.3516445-13-samitolvanen@google.com> Mime-Version: 1.0 References: <20200929214631.3516445-1-samitolvanen@google.com> X-Mailer: git-send-email 2.28.0.709.gb0816b6eb0-goog Subject: [PATCH v4 12/29] kbuild: lto: fix module versioning From: Sami Tolvanen To: Masahiro Yamada , Will Deacon , Steven Rostedt Cc: Peter Zijlstra , Greg Kroah-Hartman , "Paul E. McKenney" , Kees Cook , Nick Desaulniers , clang-built-linux@googlegroups.com, kernel-hardening@lists.openwall.com, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, x86@kernel.org, Sami Tolvanen With CONFIG_MODVERSIONS, version information is linked into each compilation unit that exports symbols. With LTO, we cannot use this method as all C code is compiled into LLVM bitcode instead. This change collects symbol versions into .symversions files and merges them in link-vmlinux.sh where they are all linked into vmlinux.o at the same time. Signed-off-by: Sami Tolvanen Reviewed-by: Kees Cook --- .gitignore | 1 + Makefile | 3 ++- arch/Kconfig | 1 - scripts/Makefile.build | 33 +++++++++++++++++++++++++++++++-- scripts/Makefile.modpost | 6 +++++- scripts/link-vmlinux.sh | 25 ++++++++++++++++++++++++- 6 files changed, 63 insertions(+), 6 deletions(-) diff --git a/.gitignore b/.gitignore index 162bd2b67bdf..06e76dc39ffe 100644 --- a/.gitignore +++ b/.gitignore @@ -41,6 +41,7 @@ *.so.dbg *.su *.symtypes +*.symversions *.tab.[ch] *.tar *.xz diff --git a/Makefile b/Makefile index 8e2eaf6452ba..23cdb475c445 100644 --- a/Makefile +++ b/Makefile @@ -1827,7 +1827,8 @@ clean: $(clean-dirs) -o -name '.tmp_*.o.*' \ -o -name '*.c.[012]*.*' \ -o -name '*.ll' \ - -o -name '*.gcno' \) -type f -print | xargs rm -f + -o -name '*.gcno' \ + -o -name '*.*.symversions' \) -type f -print | xargs rm -f # Generate tags for editors # --------------------------------------------------------------------------- diff --git a/arch/Kconfig b/arch/Kconfig index 0742ec643d79..520e900efc75 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -603,7 +603,6 @@ config LTO_CLANG depends on !FTRACE_MCOUNT_RECORD depends on !KASAN depends on !GCOV_KERNEL - depends on !MODVERSIONS select LTO help This option enables Clang's Link Time Optimization (LTO), which diff --git a/scripts/Makefile.build b/scripts/Makefile.build index ed74b2f986f7..eae2f5386a03 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -166,6 +166,15 @@ ifdef CONFIG_MODVERSIONS # the actual value of the checksum generated by genksyms # o remove .tmp_.o to .o +ifdef CONFIG_LTO_CLANG +# Generate .o.symversions files for each .o with exported symbols, and link these +# to the kernel and/or modules at the end. +cmd_modversions_c = \ + if $(NM) $@ 2>/dev/null | grep -q __ksymtab; then \ + $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ + > $@.symversions; \ + fi; +else cmd_modversions_c = \ if $(OBJDUMP) -h $@ | grep -q __ksymtab; then \ $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ @@ -177,6 +186,7 @@ cmd_modversions_c = \ rm -f $(@D)/.tmp_$(@F:.o=.ver); \ fi endif +endif ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT # compiler will not generate __mcount_loc use recordmcount or recordmcount.pl @@ -390,6 +400,18 @@ $(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 +quiet_cmd_update_lto_symversions = SYMVER $@ +ifeq ($(CONFIG_LTO_CLANG) $(CONFIG_MODVERSIONS),y y) + cmd_update_lto_symversions = \ + rm -f $@.symversions \ + $(foreach n, $(filter-out FORCE,$^), \ + $(if $(wildcard $(n).symversions), \ + ; 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) # @@ -397,8 +419,11 @@ $(subdir-modorder): $(obj)/%/modules.order: $(obj)/% ; quiet_cmd_ar_builtin = AR $@ cmd_ar_builtin = rm -f $@; $(AR) cDPrST $@ $(real-prereqs) +quiet_cmd_ar_and_symver = AR $@ + cmd_ar_and_symver = $(cmd_update_lto_symversions); $(cmd_ar_builtin) + $(obj)/built-in.a: $(real-obj-y) FORCE - $(call if_changed,ar_builtin) + $(call if_changed,ar_and_symver) # # Rule to create modules.order file @@ -418,8 +443,11 @@ $(obj)/modules.order: $(obj-m) FORCE # # Rule to compile a set of .o files into one .a file (with symbol table) # +quiet_cmd_ar_lib = AR $@ + cmd_ar_lib = $(cmd_update_lto_symversions); $(cmd_ar) + $(obj)/lib.a: $(lib-y) FORCE - $(call if_changed,ar) + $(call if_changed,ar_lib) # NOTE: # Do not replace $(filter %.o,^) with $(real-prereqs). When a single object @@ -428,6 +456,7 @@ $(obj)/lib.a: $(lib-y) FORCE 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 diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost index 66e0c256403c..753725b88683 100644 --- a/scripts/Makefile.modpost +++ b/scripts/Makefile.modpost @@ -108,7 +108,11 @@ ifdef CONFIG_LTO_CLANG prelink-ext = .lto quiet_cmd_cc_lto_link_modules = LTO [M] $@ -cmd_cc_lto_link_modules = $(LD) $(ld_flags) -r -o $@ --whole-archive $^ +cmd_cc_lto_link_modules = \ + $(LD) $(ld_flags) -r -o $@ \ + $(shell [ -s $(@:.lto.o=.o.symversions) ] && \ + echo -T $(@:.lto.o=.o.symversions)) \ + --whole-archive $^ %.lto.o: %.o $(call if_changed,cc_lto_link_modules) diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index ebb9f912aab6..3e99a19b9195 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -43,11 +43,28 @@ info() fi } +# If CONFIG_LTO_CLANG is selected, collect generated symbol versions into +# .tmp_symversions.lds +gen_symversions() +{ + info GEN .tmp_symversions.lds + rm -f .tmp_symversions.lds + + for a in ${KBUILD_VMLINUX_OBJS} ${KBUILD_VMLINUX_LIBS}; do + for o in $(${AR} t $a 2>/dev/null); do + if [ -f ${o}.symversions ]; then + cat ${o}.symversions >> .tmp_symversions.lds + fi + done + done +} + # Link of vmlinux.o used for section mismatch analysis # ${1} output file modpost_link() { local objects + local lds="" objects="--whole-archive \ ${KBUILD_VMLINUX_OBJS} \ @@ -57,6 +74,11 @@ modpost_link() --end-group" if [ -n "${CONFIG_LTO_CLANG}" ]; then + if [ -n "${CONFIG_MODVERSIONS}" ]; then + gen_symversions + lds="${lds} -T .tmp_symversions.lds" + fi + # This might take a while, so indicate that we're doing # an LTO link info LTO ${1} @@ -64,7 +86,7 @@ modpost_link() info LD ${1} fi - ${LD} ${KBUILD_LDFLAGS} -r -o ${1} ${objects} + ${LD} ${KBUILD_LDFLAGS} -r -o ${1} ${lds} ${objects} } objtool_link() @@ -242,6 +264,7 @@ cleanup() { rm -f .btf.* rm -f .tmp_System.map + rm -f .tmp_symversions.lds rm -f .tmp_vmlinux* rm -f System.map rm -f vmlinux