Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 34D75C6FD1F for ; Fri, 10 Mar 2023 14:35:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232585AbjCJOfk (ORCPT ); Fri, 10 Mar 2023 09:35:40 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44360 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232565AbjCJOfa (ORCPT ); Fri, 10 Mar 2023 09:35:30 -0500 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 2AADCEDB59; Fri, 10 Mar 2023 06:35:23 -0800 (PST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 1F6E1C14; Fri, 10 Mar 2023 06:36:06 -0800 (PST) Received: from [192.168.4.21] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id F143F3F71A; Fri, 10 Mar 2023 06:35:20 -0800 (PST) Message-ID: Date: Fri, 10 Mar 2023 14:35:09 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.7.1 Subject: Re: [PATCH v2] vdso: Improve cmd_vdso_check to check all dynamic relocations Content-Language: en-US To: Fangrui Song , Christophe Leroy , Andy Lutomirski , Thomas Gleixner , Arnd Bergmann Cc: "linux-s390@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-csky@vger.kernel.org" , "linux-mips@vger.kernel.org" , "loongarch@lists.linux.dev" , "linux-riscv@lists.infradead.org" , "linuxppc-dev@lists.ozlabs.org" , "linux-arm-kernel@lists.infradead.org" References: <20220830193701.1702962-1-maskray@google.com> <20220910075316.no72fdyqjvunomwm@google.com> <9ce45cd2-dcd8-11f8-e496-7efe3649e241@csgroup.eu> <20221115004625.x4wl6zbg4iiuxl5t@google.com> <3ec9737e-3d1a-c014-b91a-0e2d406a3b3d@csgroup.eu> <20221221235147.45lkqmosndritfpe@google.com> From: Vincenzo Frascino In-Reply-To: <20221221235147.45lkqmosndritfpe@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Fangrui, Apologize for the delay, I totally missed that you had a new version of your patch since it was threaded with the old one. On 12/21/22 23:51, Fangrui Song wrote: > The actual intention is that no dynamic relocation exists. However, some > GNU ld ports produce unneeded R_*_NONE. (If a port fails to determine > the exact .rel[a].dyn size, the trailing zeros become R_*_NONE > relocations. E.g. ld's powerpc port recently fixed > https://sourceware.org/bugzilla/show_bug.cgi?id=29540) R_*_NONE are > generally no-op in the dynamic loaders. So just ignore them. > > With the change, we can remove ARCH_REL_TYPE_ABS. ARCH_REL_TYPE_ABS is a > bit misnomer as ports may check RELAVETIVE/GLOB_DAT/JUMP_SLOT which are > not called "absolute relocations". (The patch is motivated by the arm64 > port missing R_AARCH64_RELATIVE.) It makes sense to update the name, it started as "absolute relocations" but then it evolved into something else. A part that, did you perform any testing with the generated vDSO libraries? > > Signed-off-by: Fangrui Song > Reviewed-by: Christophe Leroy > --- > Change from v1: > * rebase after 8ac3b5cd3e0521d92f9755e90d140382fc292510 (lib/vdso: use "grep -E" > instead of "egrep") > * change the commit message to mention an example GNU ld bug; no longer say the > patch fixes a deprecated egrep use > --- >  arch/arm/vdso/Makefile            |  3 --- >  arch/arm64/kernel/vdso/Makefile   |  3 --- >  arch/arm64/kernel/vdso32/Makefile |  3 --- >  arch/csky/kernel/vdso/Makefile    |  3 --- >  arch/loongarch/vdso/Makefile      |  3 --- >  arch/mips/vdso/Makefile           |  3 --- >  arch/powerpc/kernel/vdso/Makefile |  1 - >  arch/riscv/kernel/vdso/Makefile   |  3 --- >  arch/s390/kernel/vdso32/Makefile  |  2 -- >  arch/s390/kernel/vdso64/Makefile  |  2 -- >  arch/x86/entry/vdso/Makefile      |  4 ---- >  lib/vdso/Makefile                 | 13 ++++--------- >  12 files changed, 4 insertions(+), 39 deletions(-) > > diff --git a/arch/arm/vdso/Makefile b/arch/arm/vdso/Makefile > index a7ec06ce3785..e58197bba776 100644 > --- a/arch/arm/vdso/Makefile > +++ b/arch/arm/vdso/Makefile > @@ -1,8 +1,5 @@ >  # SPDX-License-Identifier: GPL-2.0 >   > -# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before > -# the inclusion of generic Makefile. > -ARCH_REL_TYPE_ABS := R_ARM_JUMP_SLOT|R_ARM_GLOB_DAT|R_ARM_ABS32 I would still add a comment here to say why we are including the generic Makefile to prevent that it gets accidentally removed (similar thing for every architecture touched by this patch). With that: Reviewed-by: Vincenzo Frascino # for vDSO, aarch64 Tested-by: Vincenzo Frascino # for aarch64 >  include $(srctree)/lib/vdso/Makefile >   >  hostprogs := vdsomunge > diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile > index beaf9586338f..1f2427b13410 100644 > --- a/arch/arm64/kernel/vdso/Makefile > +++ b/arch/arm64/kernel/vdso/Makefile > @@ -6,9 +6,6 @@ >  # Heavily based on the vDSO Makefiles for other archs. >  # >   > -# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before > -# the inclusion of generic Makefile. > -ARCH_REL_TYPE_ABS := R_AARCH64_JUMP_SLOT|R_AARCH64_GLOB_DAT|R_AARCH64_ABS64 >  include $(srctree)/lib/vdso/Makefile >   >  obj-vdso := vgettimeofday.o note.o sigreturn.o > diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile > index f59bd1a4ead6..d014162c5c71 100644 > --- a/arch/arm64/kernel/vdso32/Makefile > +++ b/arch/arm64/kernel/vdso32/Makefile > @@ -3,9 +3,6 @@ >  # Makefile for vdso32 >  # >   > -# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before > -# the inclusion of generic Makefile. > -ARCH_REL_TYPE_ABS := R_ARM_JUMP_SLOT|R_ARM_GLOB_DAT|R_ARM_ABS32 >  include $(srctree)/lib/vdso/Makefile >   >  # Same as cc-*option, but using CC_COMPAT instead of CC > diff --git a/arch/csky/kernel/vdso/Makefile b/arch/csky/kernel/vdso/Makefile > index 0b6909f10667..86c8c4de1b0f 100644 > --- a/arch/csky/kernel/vdso/Makefile > +++ b/arch/csky/kernel/vdso/Makefile > @@ -1,8 +1,5 @@ >  # SPDX-License-Identifier: GPL-2.0-only >   > -# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before > -# the inclusion of generic Makefile. > -ARCH_REL_TYPE_ABS := R_CKCORE_ADDR32|R_CKCORE_JUMP_SLOT >  include $(srctree)/lib/vdso/Makefile >   >  # Symbols present in the vdso > diff --git a/arch/loongarch/vdso/Makefile b/arch/loongarch/vdso/Makefile > index d89e2ac75f7b..1b2e0f149f55 100644 > --- a/arch/loongarch/vdso/Makefile > +++ b/arch/loongarch/vdso/Makefile > @@ -1,9 +1,6 @@ >  # SPDX-License-Identifier: GPL-2.0 >  # Objects to go into the VDSO. >   > -# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before > -# the inclusion of generic Makefile. > -ARCH_REL_TYPE_ABS := R_LARCH_32|R_LARCH_64|R_LARCH_MARK_LA|R_LARCH_JUMP_SLOT >  include $(srctree)/lib/vdso/Makefile >   >  obj-vdso-y := elf.o vgetcpu.o vgettimeofday.o sigreturn.o > diff --git a/arch/mips/vdso/Makefile b/arch/mips/vdso/Makefile > index 1f7d5c6c10b0..c060f3596304 100644 > --- a/arch/mips/vdso/Makefile > +++ b/arch/mips/vdso/Makefile > @@ -4,9 +4,6 @@ >  # Sanitizer runtimes are unavailable and cannot be linked here. >   KCSAN_SANITIZE            := n >   > -# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before > -# the inclusion of generic Makefile. > -ARCH_REL_TYPE_ABS := R_MIPS_JUMP_SLOT|R_MIPS_GLOB_DAT >  include $(srctree)/lib/vdso/Makefile >   >  obj-vdso-y := elf.o vgettimeofday.o sigreturn.o > diff --git a/arch/powerpc/kernel/vdso/Makefile b/arch/powerpc/kernel/vdso/Makefile > index 6a977b0d8ffc..83c347e9136f 100644 > --- a/arch/powerpc/kernel/vdso/Makefile > +++ b/arch/powerpc/kernel/vdso/Makefile > @@ -2,7 +2,6 @@ >   >  # List of files in the vdso, has to be asm only for now >   > -ARCH_REL_TYPE_ABS := > R_PPC_JUMP_SLOT|R_PPC_GLOB_DAT|R_PPC_ADDR32|R_PPC_ADDR24|R_PPC_ADDR16|R_PPC_ADDR16_LO|R_PPC_ADDR16_HI|R_PPC_ADDR16_HA|R_PPC_ADDR14|R_PPC_ADDR14_BRTAKEN|R_PPC_ADDR14_BRNTAKEN|R_PPC_REL24 >  include $(srctree)/lib/vdso/Makefile >   >  obj-vdso32 = sigtramp32-32.o gettimeofday-32.o datapage-32.o cacheflush-32.o > note-32.o getcpu-32.o > diff --git a/arch/riscv/kernel/vdso/Makefile b/arch/riscv/kernel/vdso/Makefile > index 06e6b27f3bcc..d85c37e11b21 100644 > --- a/arch/riscv/kernel/vdso/Makefile > +++ b/arch/riscv/kernel/vdso/Makefile > @@ -1,9 +1,6 @@ >  # SPDX-License-Identifier: GPL-2.0-only >  # Copied from arch/tile/kernel/vdso/Makefile >   > -# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before > -# the inclusion of generic Makefile. > -ARCH_REL_TYPE_ABS := R_RISCV_32|R_RISCV_64|R_RISCV_JUMP_SLOT >  include $(srctree)/lib/vdso/Makefile >  # Symbols present in the vdso >  vdso-syms  = rt_sigreturn > diff --git a/arch/s390/kernel/vdso32/Makefile b/arch/s390/kernel/vdso32/Makefile > index 245bddfe9bc0..e795fdbbf484 100644 > --- a/arch/s390/kernel/vdso32/Makefile > +++ b/arch/s390/kernel/vdso32/Makefile > @@ -2,8 +2,6 @@ >  # List of files in the vdso >   >  KCOV_INSTRUMENT := n > -ARCH_REL_TYPE_ABS := R_390_COPY|R_390_GLOB_DAT|R_390_JMP_SLOT|R_390_RELATIVE > -ARCH_REL_TYPE_ABS += R_390_GOT|R_390_PLT >   >  include $(srctree)/lib/vdso/Makefile >  obj-vdso32 = vdso_user_wrapper-32.o note-32.o > diff --git a/arch/s390/kernel/vdso64/Makefile b/arch/s390/kernel/vdso64/Makefile > index 9e2b95a222a9..47dbbfdfad68 100644 > --- a/arch/s390/kernel/vdso64/Makefile > +++ b/arch/s390/kernel/vdso64/Makefile > @@ -2,8 +2,6 @@ >  # List of files in the vdso >   >  KCOV_INSTRUMENT := n > -ARCH_REL_TYPE_ABS := R_390_COPY|R_390_GLOB_DAT|R_390_JMP_SLOT|R_390_RELATIVE > -ARCH_REL_TYPE_ABS += R_390_GOT|R_390_PLT >   >  include $(srctree)/lib/vdso/Makefile >  obj-vdso64 = vdso_user_wrapper.o note.o > diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile > index 838613ac15b8..b292c24acb8e 100644 > --- a/arch/x86/entry/vdso/Makefile > +++ b/arch/x86/entry/vdso/Makefile > @@ -3,10 +3,6 @@ >  # Building vDSO images for x86. >  # >   > -# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before > -# the inclusion of generic Makefile. > -ARCH_REL_TYPE_ABS := R_X86_64_JUMP_SLOT|R_X86_64_GLOB_DAT|R_X86_64_RELATIVE| > -ARCH_REL_TYPE_ABS += R_386_GLOB_DAT|R_386_JMP_SLOT|R_386_RELATIVE >  include $(srctree)/lib/vdso/Makefile >   >  # Sanitizer runtimes are unavailable and cannot be linked here. > diff --git a/lib/vdso/Makefile b/lib/vdso/Makefile > index e814061d6aa0..9f031eafc465 100644 > --- a/lib/vdso/Makefile > +++ b/lib/vdso/Makefile > @@ -5,18 +5,13 @@ GENERIC_VDSO_DIR := $(dir $(GENERIC_VDSO_MK_PATH)) >   >  c-gettimeofday-$(CONFIG_GENERIC_GETTIMEOFDAY) := $(addprefix > $(GENERIC_VDSO_DIR), gettimeofday.c) >   > -# This cmd checks that the vdso library does not contain absolute relocation > +# This cmd checks that the vdso library does not contain dynamic relocations. >  # It has to be called after the linking of the vdso library and requires it >  # as a parameter. >  # > -# $(ARCH_REL_TYPE_ABS) is defined in the arch specific makefile and corresponds > -# to the absolute relocation types printed by "objdump -R" and accepted by the > -# dynamic linker. > -ifndef ARCH_REL_TYPE_ABS > -$(error ARCH_REL_TYPE_ABS is not set) > -endif > - > +# As a workaround for some GNU ld ports which produce unneeded R_*_NONE > +# dynamic relocations, ignore R_*_NONE. >  quiet_cmd_vdso_check = VDSOCHK $@ > -      cmd_vdso_check = if $(OBJDUMP) -R $@ | grep -E -h "$(ARCH_REL_TYPE_ABS)"; \ > +      cmd_vdso_check = if $(READELF) -rW $@ | grep -v _NONE | grep -q " R_\w*_"; \ >                 then (echo >&2 "$@: dynamic relocations are not supported"; \ >                   rm -f $@; /bin/false); fi -- Regards, Vincenzo