| Message ID | 20220830193701.1702962-1-maskray@google.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | vdso: Improve cmd_vdso_check to check all dynamic relocations | expand |
On 2022-08-30, Fangrui Song wrote: >The actual intention is that no dynamic relocation exists. However, some >GNU ld ports produce unneeded R_*_NONE. (If a port is not care enough to >determine the exact .rel[a].dyn size, the trailing zeros become R_*_NONE >relocations. E.g. powerpc64le ld as of 2.38 has the issue with >defconfig.) 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.) > >While here, replace "egrep" with "grep" as "egrep" is deprecated in GNU >grep 3.7. > >Signed-off-by: Fangrui Song <maskray@google.com> >--- >[...] > Ping.
On Sat, Sep 10, 2022 at 12:53 AM Fangrui Song <maskray@google.com> wrote: > > On 2022-08-30, Fangrui Song wrote: > >The actual intention is that no dynamic relocation exists. However, some > >GNU ld ports produce unneeded R_*_NONE. (If a port is not care enough to > >determine the exact .rel[a].dyn size, the trailing zeros become R_*_NONE > >relocations. E.g. powerpc64le ld as of 2.38 has the issue with > >defconfig.) 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.) > > > >While here, replace "egrep" with "grep" as "egrep" is deprecated in GNU > >grep 3.7. > > > >Signed-off-by: Fangrui Song <maskray@google.com> > >--- > >[...] > > > > Ping. Ping^2 :)
Le 28/09/2022 à 07:25, Fangrui Song a écrit : > On Sat, Sep 10, 2022 at 12:53 AM Fangrui Song <maskray@google.com> wrote: >> >> On 2022-08-30, Fangrui Song wrote: >>> The actual intention is that no dynamic relocation exists. However, some >>> GNU ld ports produce unneeded R_*_NONE. (If a port is not care enough to >>> determine the exact .rel[a].dyn size, the trailing zeros become R_*_NONE >>> relocations. E.g. powerpc64le ld as of 2.38 has the issue with >>> defconfig.) 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.) >>> >>> While here, replace "egrep" with "grep" as "egrep" is deprecated in GNU >>> grep 3.7. >>> >>> Signed-off-by: Fangrui Song <maskray@google.com> >>> --- >>> [...] >>> >> >> Ping. > > Ping^2 :) Can you explain which ARCH_REL_TYPE_ABS can be removed with this change ? How is the verification done if ARCH_REL_TYPE_ABS is removed ?
On 2022-11-14, Christophe Leroy wrote: > > >Le 28/09/2022 à 07:25, Fangrui Song a écrit : >> On Sat, Sep 10, 2022 at 12:53 AM Fangrui Song <maskray@google.com> wrote: >>> >>> On 2022-08-30, Fangrui Song wrote: >>>> The actual intention is that no dynamic relocation exists. However, some >>>> GNU ld ports produce unneeded R_*_NONE. (If a port is not care enough to >>>> determine the exact .rel[a].dyn size, the trailing zeros become R_*_NONE >>>> relocations. E.g. powerpc64le ld as of 2.38 has the issue with >>>> defconfig.) 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.) >>>> >>>> While here, replace "egrep" with "grep" as "egrep" is deprecated in GNU >>>> grep 3.7. >>>> >>>> Signed-off-by: Fangrui Song <maskray@google.com> >>>> --- >>>> [...] >>>> >>> >>> Ping. >> >> Ping^2 :) > >Can you explain which ARCH_REL_TYPE_ABS can be removed with this change ? >How is the verification done if ARCH_REL_TYPE_ABS is removed ? All ARCH_REL_TYPE_ABS relocation types can be removed. As explained, the real intention is to check no dynamic relocation, and this is done by the new cmd_vdso_check = if $(READELF) -rW $@ | grep -v _NONE | grep -q "R_\w*_"; \ in this patch. grep -v _NONE is to work around some GNU ld ports (and likely older releases of some ports even if their latest versions are fixed) which produce unneeded R_*_NONE dynamic relocations.
On Mon, Nov 14, 2022 at 4:46 PM Fangrui Song <maskray@google.com> wrote: > > On 2022-11-14, Christophe Leroy wrote: > > > > > >Le 28/09/2022 à 07:25, Fangrui Song a écrit : > >> On Sat, Sep 10, 2022 at 12:53 AM Fangrui Song <maskray@google.com> wrote: > >>> > >>> On 2022-08-30, Fangrui Song wrote: > >>>> The actual intention is that no dynamic relocation exists. However, some > >>>> GNU ld ports produce unneeded R_*_NONE. (If a port is not care enough to > >>>> determine the exact .rel[a].dyn size, the trailing zeros become R_*_NONE > >>>> relocations. E.g. powerpc64le ld as of 2.38 has the issue with > >>>> defconfig.) 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.) > >>>> > >>>> While here, replace "egrep" with "grep" as "egrep" is deprecated in GNU > >>>> grep 3.7. > >>>> > >>>> Signed-off-by: Fangrui Song <maskray@google.com> > >>>> --- > >>>> [...] > >>>> > >>> > >>> Ping. > >> > >> Ping^2 :) > > > >Can you explain which ARCH_REL_TYPE_ABS can be removed with this change ? > >How is the verification done if ARCH_REL_TYPE_ABS is removed ? > > All ARCH_REL_TYPE_ABS relocation types can be removed. As explained, the > real intention is to check no dynamic relocation, and this is done by > the new > > cmd_vdso_check = if $(READELF) -rW $@ | grep -v _NONE | grep -q "R_\w*_"; \ > > in this patch. > > grep -v _NONE is to work around some GNU ld ports (and likely older releases > of some ports even if their latest versions are fixed) which produce > unneeded R_*_NONE dynamic relocations. Ping :)
Le 04/12/2022 à 05:50, Fangrui Song a écrit : > On Mon, Nov 14, 2022 at 4:46 PM Fangrui Song <maskray@google.com> wrote: >> >> On 2022-11-14, Christophe Leroy wrote: >>> >>> >>> Le 28/09/2022 à 07:25, Fangrui Song a écrit : >>>> On Sat, Sep 10, 2022 at 12:53 AM Fangrui Song <maskray@google.com> wrote: >>>>> >>>>> On 2022-08-30, Fangrui Song wrote: >>>>>> The actual intention is that no dynamic relocation exists. However, some >>>>>> GNU ld ports produce unneeded R_*_NONE. (If a port is not care enough to >>>>>> determine the exact .rel[a].dyn size, the trailing zeros become R_*_NONE >>>>>> relocations. E.g. powerpc64le ld as of 2.38 has the issue with >>>>>> defconfig.) 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.) >>>>>> >>>>>> While here, replace "egrep" with "grep" as "egrep" is deprecated in GNU >>>>>> grep 3.7. >>>>>> >>>>>> Signed-off-by: Fangrui Song <maskray@google.com> >>>>>> --- >>>>>> [...] >>>>>> >>>>> >>>>> Ping. >>>> >>>> Ping^2 :) >>> >>> Can you explain which ARCH_REL_TYPE_ABS can be removed with this change ? >>> How is the verification done if ARCH_REL_TYPE_ABS is removed ? >> >> All ARCH_REL_TYPE_ABS relocation types can be removed. As explained, the >> real intention is to check no dynamic relocation, and this is done by >> the new Well, there was a typo in my question, I wanted to ask 'why', not 'which'. >> >> cmd_vdso_check = if $(READELF) -rW $@ | grep -v _NONE | grep -q "R_\w*_"; \ >> >> in this patch. >> >> grep -v _NONE is to work around some GNU ld ports (and likely older releases >> of some ports even if their latest versions are fixed) which produce >> unneeded R_*_NONE dynamic relocations. > > Ping :) Ok, that seems to work on powerpc. Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
On Sun, Dec 4, 2022 at 8:58 AM Christophe Leroy <christophe.leroy@csgroup.eu> wrote: > > > > Le 04/12/2022 à 05:50, Fangrui Song a écrit : > > On Mon, Nov 14, 2022 at 4:46 PM Fangrui Song <maskray@google.com> wrote: > >> > >> On 2022-11-14, Christophe Leroy wrote: > >>> > >>> > >>> Le 28/09/2022 à 07:25, Fangrui Song a écrit : > >>>> On Sat, Sep 10, 2022 at 12:53 AM Fangrui Song <maskray@google.com> wrote: > >>>>> > >>>>> On 2022-08-30, Fangrui Song wrote: > >>>>>> The actual intention is that no dynamic relocation exists. However, some > >>>>>> GNU ld ports produce unneeded R_*_NONE. (If a port is not care enough to > >>>>>> determine the exact .rel[a].dyn size, the trailing zeros become R_*_NONE > >>>>>> relocations. E.g. powerpc64le ld as of 2.38 has the issue with > >>>>>> defconfig.) 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.) > >>>>>> > >>>>>> While here, replace "egrep" with "grep" as "egrep" is deprecated in GNU > >>>>>> grep 3.7. > >>>>>> > >>>>>> Signed-off-by: Fangrui Song <maskray@google.com> > >>>>>> --- > >>>>>> [...] > >>>>>> > >>>>> > >>>>> Ping. > >>>> > >>>> Ping^2 :) > >>> > >>> Can you explain which ARCH_REL_TYPE_ABS can be removed with this change ? > >>> How is the verification done if ARCH_REL_TYPE_ABS is removed ? > >> > >> All ARCH_REL_TYPE_ABS relocation types can be removed. As explained, the > >> real intention is to check no dynamic relocation, and this is done by > >> the new > > Well, there was a typo in my question, I wanted to ask 'why', not 'which'. > > >> > >> cmd_vdso_check = if $(READELF) -rW $@ | grep -v _NONE | grep -q "R_\w*_"; \ > >> > >> in this patch. > >> > >> grep -v _NONE is to work around some GNU ld ports (and likely older releases > >> of some ports even if their latest versions are fixed) which produce > >> unneeded R_*_NONE dynamic relocations. > > > > Ping :) > > Ok, that seems to work on powerpc. > > Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu> Thanks. Can a maintainer pick up this commit?
diff --git a/arch/arm/vdso/Makefile b/arch/arm/vdso/Makefile index 8ca1c9f262a2..5ebd2e6f7d46 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 include $(srctree)/lib/vdso/Makefile hostprogs := vdsomunge diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile index bafbf78fab77..66dc4f338a86 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 36c8f66cad25..48d713d59ef2 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 f72658b3a53f..cea97abffc03 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 096b0bf1335f..d3c5be32034d 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 f2e065671e4d..77d6bed3a700 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 12f6c4d714cd..a97f3630ca20 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 c415a685d61b..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 $@ | egrep -h "$(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
The actual intention is that no dynamic relocation exists. However, some GNU ld ports produce unneeded R_*_NONE. (If a port is not care enough to determine the exact .rel[a].dyn size, the trailing zeros become R_*_NONE relocations. E.g. powerpc64le ld as of 2.38 has the issue with defconfig.) 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.) While here, replace "egrep" with "grep" as "egrep" is deprecated in GNU grep 3.7. Signed-off-by: Fangrui Song <maskray@google.com> --- 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(-)