Re: [PATCH 4.14 09/69] x86: vdso: Use $LD instead of $CC to link
On Fri, Apr 26, 2019 at 06:34:22AM -0700, Nathan Chancellor wrote:
> On Fri, Apr 26, 2019 at 01:23:17PM +, Rantala, Tommi T. (Nokia -
> FI/Espoo) wrote:
> > On Fri, 2019-04-26 at 05:48 -0700, Nathan Chancellor wrote:
> > > On Fri, Apr 26, 2019 at 11:41:30AM +, Rantala, Tommi T. (Nokia -
> > > FI/Espoo) wrote:
> > > > On Mon, 2019-04-15 at 20:58 +0200, Greg Kroah-Hartman wrote:
> > > > > commit 379d98ddf41344273d9718556f761420f4dc80b3 upstream.
> > > > >
> > > >
> > > > Hi,
> > > >
> > > > With this patch in 4.14.112 build-id is now missing in vdso32.so:
> > > >
> > > > $ file arch/x86/entry/vdso/vdso*so*
> > > > arch/x86/entry/vdso/vdso32.so: ELF 32-bit LSB pie executable,
> > > > Intel
> > > > 80386, version 1 (SYSV), dynamically linked, stripped
> > > > arch/x86/entry/vdso/vdso32.so.dbg: ELF 32-bit LSB pie executable,
> > > > Intel
> > > > 80386, version 1 (SYSV), dynamically linked, with debug_info, not
> > > > stripped
> > > > arch/x86/entry/vdso/vdso64.so: ELF 64-bit LSB pie executable,
> > > > x86-
> > > > 64, version 1 (SYSV), dynamically linked,
> > > > BuildID[sha1]=d80730a5b561a3161e488a369d1c76c250b584b4, stripped
> > > > arch/x86/entry/vdso/vdso64.so.dbg: ELF 64-bit LSB pie executable,
> > > > x86-
> > > > 64, version 1 (SYSV), dynamically linked,
> > > > BuildID[sha1]=d80730a5b561a3161e488a369d1c76c250b584b4, with
> > > > debug_info, not stripped
> > > >
> > > >
> > > > Based on quick check, "$(call ld-option, --build-id)" fails due to
> > > > some
> > > > 32/64 bit mismatch, so the --build-id linker flag is not used when
> > > > linking vdso32.so
> > > >
> > > > Perhaps scripts/Kbuild.include is missing some change in 4.14.y to
> > > > make
> > > > this work properly.
> > > >
> > >
> > > Hi Tommi,
> > >
> > > This appears to be fixed by commit 0294e6f4a000 ("kbuild: simplify
> > > ld-option implementation") upstream. Could you test the attached
> > > backport and make sure everything works on your end? Assuming that it
> > > does, I will test the other stable releases and see if this is needed
> > > and send those backports along.
> >
> > Yes this patch fixes it. Many thanks!
>
> Thanks for verifying!
>
> Greg, attached are backports for that commit for 4.4, 4.9, and 4.14. It
> appeared in 4.16 so it is not needed with a newer version.
Now queued up, thanks!
greg k-h
Re: [PATCH 4.14 09/69] x86: vdso: Use $LD instead of $CC to link
On Fri, Apr 26, 2019 at 01:23:17PM +, Rantala, Tommi T. (Nokia - FI/Espoo)
wrote:
> On Fri, 2019-04-26 at 05:48 -0700, Nathan Chancellor wrote:
> > On Fri, Apr 26, 2019 at 11:41:30AM +, Rantala, Tommi T. (Nokia -
> > FI/Espoo) wrote:
> > > On Mon, 2019-04-15 at 20:58 +0200, Greg Kroah-Hartman wrote:
> > > > commit 379d98ddf41344273d9718556f761420f4dc80b3 upstream.
> > > >
> > >
> > > Hi,
> > >
> > > With this patch in 4.14.112 build-id is now missing in vdso32.so:
> > >
> > > $ file arch/x86/entry/vdso/vdso*so*
> > > arch/x86/entry/vdso/vdso32.so: ELF 32-bit LSB pie executable,
> > > Intel
> > > 80386, version 1 (SYSV), dynamically linked, stripped
> > > arch/x86/entry/vdso/vdso32.so.dbg: ELF 32-bit LSB pie executable,
> > > Intel
> > > 80386, version 1 (SYSV), dynamically linked, with debug_info, not
> > > stripped
> > > arch/x86/entry/vdso/vdso64.so: ELF 64-bit LSB pie executable,
> > > x86-
> > > 64, version 1 (SYSV), dynamically linked,
> > > BuildID[sha1]=d80730a5b561a3161e488a369d1c76c250b584b4, stripped
> > > arch/x86/entry/vdso/vdso64.so.dbg: ELF 64-bit LSB pie executable,
> > > x86-
> > > 64, version 1 (SYSV), dynamically linked,
> > > BuildID[sha1]=d80730a5b561a3161e488a369d1c76c250b584b4, with
> > > debug_info, not stripped
> > >
> > >
> > > Based on quick check, "$(call ld-option, --build-id)" fails due to
> > > some
> > > 32/64 bit mismatch, so the --build-id linker flag is not used when
> > > linking vdso32.so
> > >
> > > Perhaps scripts/Kbuild.include is missing some change in 4.14.y to
> > > make
> > > this work properly.
> > >
> >
> > Hi Tommi,
> >
> > This appears to be fixed by commit 0294e6f4a000 ("kbuild: simplify
> > ld-option implementation") upstream. Could you test the attached
> > backport and make sure everything works on your end? Assuming that it
> > does, I will test the other stable releases and see if this is needed
> > and send those backports along.
>
> Yes this patch fixes it. Many thanks!
Thanks for verifying!
Greg, attached are backports for that commit for 4.4, 4.9, and 4.14. It
appeared in 4.16 so it is not needed with a newer version.
Thanks,
Nathan
>
> -Tommi
>
> > Thanks and sorry for the trouble!
> > Nathan
> >
> > > -Tommi
> > >
> > > > The vdso{32,64}.so can fail to link with CC=clang when clang
> > > > tries to
> > > > find
> > > > a suitable GCC toolchain to link these libraries with.
> > > >
> > > > /usr/bin/ld: arch/x86/entry/vdso/vclock_gettime.o:
> > > > access beyond end of merged section (782)
> > > >
> > > > This happens because the host environment leaked into the cross
> > > > compiler
> > > > environment due to the way clang searches for suitable GCC
> > > > toolchains.
> > > >
> > > > Clang is a retargetable compiler, and each invocation of it must
> > > > provide
> > > > --target= --gcc-toolchain= to allow it to
> > > > find
> > > > the
> > > > correct binutils for cross compilation. These flags had been
> > > > added to
> > > > KBUILD_CFLAGS, but the vdso code uses CC and not KBUILD_CFLAGS
> > > > (for
> > > > various
> > > > reasons) which breaks clang's ability to find the correct linker
> > > > when
> > > > cross
> > > > compiling.
> > > >
> > > > Most of the time this goes unnoticed because the host linker is
> > > > new
> > > > enough
> > > > to work anyway, or is incompatible and skipped, but this cannot
> > > > be
> > > > reliably
> > > > assumed.
> > > >
> > > > This change alters the vdso makefile to just use LD directly,
> > > > which
> > > > bypasses clang and thus the searching problem. The makefile will
> > > > just
> > > > use
> > > > ${CROSS_COMPILE}ld instead, which is always what we want. This
> > > > matches the
> > > > method used to link vmlinux.
> > > >
> > > > This drops references to DISABLE_LTO; this option doesn't seem to
> > > > be
> > > > set
> > > > anywhere, and not knowing what its possible values are, it's not
> > > > clear how
> > > > to convert it from CC to LD flag.
> > > >
> > > > Signed-off-by: Alistair Strachan
> > > > Signed-off-by: Thomas Gleixner
> > > > Acked-by: Andy Lutomirski
> > > > Cc: "H. Peter Anvin"
> > > > Cc: Greg Kroah-Hartman
> > > > Cc: kernel-t...@android.com
> > > > Cc: j...@joelfernandes.org
> > > > Cc: Andi Kleen
> > > > Link:
> > > > https://lkml.kernel.org/r/20180803173931.117515-1-astrac...@google.com
> > > > Signed-off-by: Nathan Chancellor
> > > > Signed-off-by: Sasha Levin
> > > > ---
> > > > arch/x86/entry/vdso/Makefile | 22 +-
> > > > 1 file changed, 9 insertions(+), 13 deletions(-)
> > > >
> > > > diff --git a/arch/x86/entry/vdso/Makefile
> > > > b/arch/x86/entry/vdso/Makefile
> > > > index 0a550dc5c525..0defcc939ab4 100644
> > > > --- a/arch/x86/entry/vdso/Makefile
> > > > +++ b/arch/x86/entry/vdso/Makefile
> > > > @@ -48,10 +48,8 @@ targets += $(vdso_img_sodbg)
> > > >
> > > > export CPPFLAGS_vdso.lds += -P -C
> > > >
> > > > -VDSO_LDFLAGS_vdso.lds = -m64 -Wl,-soname=linux-vdso.so.1 \
> > > > -
Re: [PATCH 4.14 09/69] x86: vdso: Use $LD instead of $CC to link
On Fri, 2019-04-26 at 05:48 -0700, Nathan Chancellor wrote:
> On Fri, Apr 26, 2019 at 11:41:30AM +, Rantala, Tommi T. (Nokia -
> FI/Espoo) wrote:
> > On Mon, 2019-04-15 at 20:58 +0200, Greg Kroah-Hartman wrote:
> > > commit 379d98ddf41344273d9718556f761420f4dc80b3 upstream.
> > >
> >
> > Hi,
> >
> > With this patch in 4.14.112 build-id is now missing in vdso32.so:
> >
> > $ file arch/x86/entry/vdso/vdso*so*
> > arch/x86/entry/vdso/vdso32.so: ELF 32-bit LSB pie executable,
> > Intel
> > 80386, version 1 (SYSV), dynamically linked, stripped
> > arch/x86/entry/vdso/vdso32.so.dbg: ELF 32-bit LSB pie executable,
> > Intel
> > 80386, version 1 (SYSV), dynamically linked, with debug_info, not
> > stripped
> > arch/x86/entry/vdso/vdso64.so: ELF 64-bit LSB pie executable,
> > x86-
> > 64, version 1 (SYSV), dynamically linked,
> > BuildID[sha1]=d80730a5b561a3161e488a369d1c76c250b584b4, stripped
> > arch/x86/entry/vdso/vdso64.so.dbg: ELF 64-bit LSB pie executable,
> > x86-
> > 64, version 1 (SYSV), dynamically linked,
> > BuildID[sha1]=d80730a5b561a3161e488a369d1c76c250b584b4, with
> > debug_info, not stripped
> >
> >
> > Based on quick check, "$(call ld-option, --build-id)" fails due to
> > some
> > 32/64 bit mismatch, so the --build-id linker flag is not used when
> > linking vdso32.so
> >
> > Perhaps scripts/Kbuild.include is missing some change in 4.14.y to
> > make
> > this work properly.
> >
>
> Hi Tommi,
>
> This appears to be fixed by commit 0294e6f4a000 ("kbuild: simplify
> ld-option implementation") upstream. Could you test the attached
> backport and make sure everything works on your end? Assuming that it
> does, I will test the other stable releases and see if this is needed
> and send those backports along.
Yes this patch fixes it. Many thanks!
-Tommi
> Thanks and sorry for the trouble!
> Nathan
>
> > -Tommi
> >
> > > The vdso{32,64}.so can fail to link with CC=clang when clang
> > > tries to
> > > find
> > > a suitable GCC toolchain to link these libraries with.
> > >
> > > /usr/bin/ld: arch/x86/entry/vdso/vclock_gettime.o:
> > > access beyond end of merged section (782)
> > >
> > > This happens because the host environment leaked into the cross
> > > compiler
> > > environment due to the way clang searches for suitable GCC
> > > toolchains.
> > >
> > > Clang is a retargetable compiler, and each invocation of it must
> > > provide
> > > --target= --gcc-toolchain= to allow it to
> > > find
> > > the
> > > correct binutils for cross compilation. These flags had been
> > > added to
> > > KBUILD_CFLAGS, but the vdso code uses CC and not KBUILD_CFLAGS
> > > (for
> > > various
> > > reasons) which breaks clang's ability to find the correct linker
> > > when
> > > cross
> > > compiling.
> > >
> > > Most of the time this goes unnoticed because the host linker is
> > > new
> > > enough
> > > to work anyway, or is incompatible and skipped, but this cannot
> > > be
> > > reliably
> > > assumed.
> > >
> > > This change alters the vdso makefile to just use LD directly,
> > > which
> > > bypasses clang and thus the searching problem. The makefile will
> > > just
> > > use
> > > ${CROSS_COMPILE}ld instead, which is always what we want. This
> > > matches the
> > > method used to link vmlinux.
> > >
> > > This drops references to DISABLE_LTO; this option doesn't seem to
> > > be
> > > set
> > > anywhere, and not knowing what its possible values are, it's not
> > > clear how
> > > to convert it from CC to LD flag.
> > >
> > > Signed-off-by: Alistair Strachan
> > > Signed-off-by: Thomas Gleixner
> > > Acked-by: Andy Lutomirski
> > > Cc: "H. Peter Anvin"
> > > Cc: Greg Kroah-Hartman
> > > Cc: kernel-t...@android.com
> > > Cc: j...@joelfernandes.org
> > > Cc: Andi Kleen
> > > Link:
> > > https://lkml.kernel.org/r/20180803173931.117515-1-astrac...@google.com
> > > Signed-off-by: Nathan Chancellor
> > > Signed-off-by: Sasha Levin
> > > ---
> > > arch/x86/entry/vdso/Makefile | 22 +-
> > > 1 file changed, 9 insertions(+), 13 deletions(-)
> > >
> > > diff --git a/arch/x86/entry/vdso/Makefile
> > > b/arch/x86/entry/vdso/Makefile
> > > index 0a550dc5c525..0defcc939ab4 100644
> > > --- a/arch/x86/entry/vdso/Makefile
> > > +++ b/arch/x86/entry/vdso/Makefile
> > > @@ -48,10 +48,8 @@ targets += $(vdso_img_sodbg)
> > >
> > > export CPPFLAGS_vdso.lds += -P -C
> > >
> > > -VDSO_LDFLAGS_vdso.lds = -m64 -Wl,-soname=linux-vdso.so.1 \
> > > - -Wl,--no-undefined \
> > > - -Wl,-z,max-page-size=4096 -Wl,-z,common-page-
> > > size=4096 \
> > > - $(DISABLE_LTO)
> > > +VDSO_LDFLAGS_vdso.lds = -m elf_x86_64 -soname linux-vdso.so.1 --
> > > no-
> > > undefined \
> > > + -z max-page-size=4096 -z common-page-size=4096
> > >
> > > $(obj)/vdso64.so.dbg: $(src)/vdso.lds $(vobjs) FORCE
> > > $(call if_changed,vdso)
> > > @@ -103,10 +101,8 @@ CFLAGS_REMOVE_vvar.o = -pg
> > > #
> > >
> > > CPPFLAGS_vdsox32.lds
Re: [PATCH 4.14 09/69] x86: vdso: Use $LD instead of $CC to link
On Fri, Apr 26, 2019 at 11:41:30AM +, Rantala, Tommi T. (Nokia - FI/Espoo)
wrote:
> On Mon, 2019-04-15 at 20:58 +0200, Greg Kroah-Hartman wrote:
> > commit 379d98ddf41344273d9718556f761420f4dc80b3 upstream.
> >
>
> Hi,
>
> With this patch in 4.14.112 build-id is now missing in vdso32.so:
>
> $ file arch/x86/entry/vdso/vdso*so*
> arch/x86/entry/vdso/vdso32.so: ELF 32-bit LSB pie executable, Intel
> 80386, version 1 (SYSV), dynamically linked, stripped
> arch/x86/entry/vdso/vdso32.so.dbg: ELF 32-bit LSB pie executable, Intel
> 80386, version 1 (SYSV), dynamically linked, with debug_info, not
> stripped
> arch/x86/entry/vdso/vdso64.so: ELF 64-bit LSB pie executable, x86-
> 64, version 1 (SYSV), dynamically linked,
> BuildID[sha1]=d80730a5b561a3161e488a369d1c76c250b584b4, stripped
> arch/x86/entry/vdso/vdso64.so.dbg: ELF 64-bit LSB pie executable, x86-
> 64, version 1 (SYSV), dynamically linked,
> BuildID[sha1]=d80730a5b561a3161e488a369d1c76c250b584b4, with
> debug_info, not stripped
>
>
> Based on quick check, "$(call ld-option, --build-id)" fails due to some
> 32/64 bit mismatch, so the --build-id linker flag is not used when
> linking vdso32.so
>
> Perhaps scripts/Kbuild.include is missing some change in 4.14.y to make
> this work properly.
>
Hi Tommi,
This appears to be fixed by commit 0294e6f4a000 ("kbuild: simplify
ld-option implementation") upstream. Could you test the attached
backport and make sure everything works on your end? Assuming that it
does, I will test the other stable releases and see if this is needed
and send those backports along.
Thanks and sorry for the trouble!
Nathan
> -Tommi
>
> > The vdso{32,64}.so can fail to link with CC=clang when clang tries to
> > find
> > a suitable GCC toolchain to link these libraries with.
> >
> > /usr/bin/ld: arch/x86/entry/vdso/vclock_gettime.o:
> > access beyond end of merged section (782)
> >
> > This happens because the host environment leaked into the cross
> > compiler
> > environment due to the way clang searches for suitable GCC
> > toolchains.
> >
> > Clang is a retargetable compiler, and each invocation of it must
> > provide
> > --target= --gcc-toolchain= to allow it to find
> > the
> > correct binutils for cross compilation. These flags had been added to
> > KBUILD_CFLAGS, but the vdso code uses CC and not KBUILD_CFLAGS (for
> > various
> > reasons) which breaks clang's ability to find the correct linker when
> > cross
> > compiling.
> >
> > Most of the time this goes unnoticed because the host linker is new
> > enough
> > to work anyway, or is incompatible and skipped, but this cannot be
> > reliably
> > assumed.
> >
> > This change alters the vdso makefile to just use LD directly, which
> > bypasses clang and thus the searching problem. The makefile will just
> > use
> > ${CROSS_COMPILE}ld instead, which is always what we want. This
> > matches the
> > method used to link vmlinux.
> >
> > This drops references to DISABLE_LTO; this option doesn't seem to be
> > set
> > anywhere, and not knowing what its possible values are, it's not
> > clear how
> > to convert it from CC to LD flag.
> >
> > Signed-off-by: Alistair Strachan
> > Signed-off-by: Thomas Gleixner
> > Acked-by: Andy Lutomirski
> > Cc: "H. Peter Anvin"
> > Cc: Greg Kroah-Hartman
> > Cc: kernel-t...@android.com
> > Cc: j...@joelfernandes.org
> > Cc: Andi Kleen
> > Link:
> > https://lkml.kernel.org/r/20180803173931.117515-1-astrac...@google.com
> > Signed-off-by: Nathan Chancellor
> > Signed-off-by: Sasha Levin
> > ---
> > arch/x86/entry/vdso/Makefile | 22 +-
> > 1 file changed, 9 insertions(+), 13 deletions(-)
> >
> > diff --git a/arch/x86/entry/vdso/Makefile
> > b/arch/x86/entry/vdso/Makefile
> > index 0a550dc5c525..0defcc939ab4 100644
> > --- a/arch/x86/entry/vdso/Makefile
> > +++ b/arch/x86/entry/vdso/Makefile
> > @@ -48,10 +48,8 @@ targets += $(vdso_img_sodbg)
> >
> > export CPPFLAGS_vdso.lds += -P -C
> >
> > -VDSO_LDFLAGS_vdso.lds = -m64 -Wl,-soname=linux-vdso.so.1 \
> > - -Wl,--no-undefined \
> > - -Wl,-z,max-page-size=4096 -Wl,-z,common-page-
> > size=4096 \
> > - $(DISABLE_LTO)
> > +VDSO_LDFLAGS_vdso.lds = -m elf_x86_64 -soname linux-vdso.so.1 --no-
> > undefined \
> > + -z max-page-size=4096 -z common-page-size=4096
> >
> > $(obj)/vdso64.so.dbg: $(src)/vdso.lds $(vobjs) FORCE
> > $(call if_changed,vdso)
> > @@ -103,10 +101,8 @@ CFLAGS_REMOVE_vvar.o = -pg
> > #
> >
> > CPPFLAGS_vdsox32.lds = $(CPPFLAGS_vdso.lds)
> > -VDSO_LDFLAGS_vdsox32.lds = -Wl,-m,elf32_x86_64 \
> > - -Wl,-soname=linux-vdso.so.1 \
> > - -Wl,-z,max-page-size=4096 \
> > - -Wl,-z,common-page-size=4096
> > +VDSO_LDFLAGS_vdsox32.lds = -m elf32_x86_64 -soname linux-vdso.so.1 \
> > + -z max-page-size=4096 -z common-page-
> > size=4096
> >
> > # 64-bit objects to re-brand as
Re: [PATCH 4.14 09/69] x86: vdso: Use $LD instead of $CC to link
On Mon, 2019-04-15 at 20:58 +0200, Greg Kroah-Hartman wrote:
> commit 379d98ddf41344273d9718556f761420f4dc80b3 upstream.
>
Hi,
With this patch in 4.14.112 build-id is now missing in vdso32.so:
$ file arch/x86/entry/vdso/vdso*so*
arch/x86/entry/vdso/vdso32.so: ELF 32-bit LSB pie executable, Intel
80386, version 1 (SYSV), dynamically linked, stripped
arch/x86/entry/vdso/vdso32.so.dbg: ELF 32-bit LSB pie executable, Intel
80386, version 1 (SYSV), dynamically linked, with debug_info, not
stripped
arch/x86/entry/vdso/vdso64.so: ELF 64-bit LSB pie executable, x86-
64, version 1 (SYSV), dynamically linked,
BuildID[sha1]=d80730a5b561a3161e488a369d1c76c250b584b4, stripped
arch/x86/entry/vdso/vdso64.so.dbg: ELF 64-bit LSB pie executable, x86-
64, version 1 (SYSV), dynamically linked,
BuildID[sha1]=d80730a5b561a3161e488a369d1c76c250b584b4, with
debug_info, not stripped
Based on quick check, "$(call ld-option, --build-id)" fails due to some
32/64 bit mismatch, so the --build-id linker flag is not used when
linking vdso32.so
Perhaps scripts/Kbuild.include is missing some change in 4.14.y to make
this work properly.
-Tommi
> The vdso{32,64}.so can fail to link with CC=clang when clang tries to
> find
> a suitable GCC toolchain to link these libraries with.
>
> /usr/bin/ld: arch/x86/entry/vdso/vclock_gettime.o:
> access beyond end of merged section (782)
>
> This happens because the host environment leaked into the cross
> compiler
> environment due to the way clang searches for suitable GCC
> toolchains.
>
> Clang is a retargetable compiler, and each invocation of it must
> provide
> --target= --gcc-toolchain= to allow it to find
> the
> correct binutils for cross compilation. These flags had been added to
> KBUILD_CFLAGS, but the vdso code uses CC and not KBUILD_CFLAGS (for
> various
> reasons) which breaks clang's ability to find the correct linker when
> cross
> compiling.
>
> Most of the time this goes unnoticed because the host linker is new
> enough
> to work anyway, or is incompatible and skipped, but this cannot be
> reliably
> assumed.
>
> This change alters the vdso makefile to just use LD directly, which
> bypasses clang and thus the searching problem. The makefile will just
> use
> ${CROSS_COMPILE}ld instead, which is always what we want. This
> matches the
> method used to link vmlinux.
>
> This drops references to DISABLE_LTO; this option doesn't seem to be
> set
> anywhere, and not knowing what its possible values are, it's not
> clear how
> to convert it from CC to LD flag.
>
> Signed-off-by: Alistair Strachan
> Signed-off-by: Thomas Gleixner
> Acked-by: Andy Lutomirski
> Cc: "H. Peter Anvin"
> Cc: Greg Kroah-Hartman
> Cc: kernel-t...@android.com
> Cc: j...@joelfernandes.org
> Cc: Andi Kleen
> Link:
> https://lkml.kernel.org/r/20180803173931.117515-1-astrac...@google.com
> Signed-off-by: Nathan Chancellor
> Signed-off-by: Sasha Levin
> ---
> arch/x86/entry/vdso/Makefile | 22 +-
> 1 file changed, 9 insertions(+), 13 deletions(-)
>
> diff --git a/arch/x86/entry/vdso/Makefile
> b/arch/x86/entry/vdso/Makefile
> index 0a550dc5c525..0defcc939ab4 100644
> --- a/arch/x86/entry/vdso/Makefile
> +++ b/arch/x86/entry/vdso/Makefile
> @@ -48,10 +48,8 @@ targets += $(vdso_img_sodbg)
>
> export CPPFLAGS_vdso.lds += -P -C
>
> -VDSO_LDFLAGS_vdso.lds = -m64 -Wl,-soname=linux-vdso.so.1 \
> - -Wl,--no-undefined \
> - -Wl,-z,max-page-size=4096 -Wl,-z,common-page-
> size=4096 \
> - $(DISABLE_LTO)
> +VDSO_LDFLAGS_vdso.lds = -m elf_x86_64 -soname linux-vdso.so.1 --no-
> undefined \
> + -z max-page-size=4096 -z common-page-size=4096
>
> $(obj)/vdso64.so.dbg: $(src)/vdso.lds $(vobjs) FORCE
> $(call if_changed,vdso)
> @@ -103,10 +101,8 @@ CFLAGS_REMOVE_vvar.o = -pg
> #
>
> CPPFLAGS_vdsox32.lds = $(CPPFLAGS_vdso.lds)
> -VDSO_LDFLAGS_vdsox32.lds = -Wl,-m,elf32_x86_64 \
> --Wl,-soname=linux-vdso.so.1 \
> --Wl,-z,max-page-size=4096 \
> --Wl,-z,common-page-size=4096
> +VDSO_LDFLAGS_vdsox32.lds = -m elf32_x86_64 -soname linux-vdso.so.1 \
> +-z max-page-size=4096 -z common-page-
> size=4096
>
> # 64-bit objects to re-brand as x32
> vobjs64-for-x32 := $(filter-out $(vobjs-nox32),$(vobjs-y))
> @@ -134,7 +130,7 @@ $(obj)/vdsox32.so.dbg: $(src)/vdsox32.lds
> $(vobjx32s) FORCE
> $(call if_changed,vdso)
>
> CPPFLAGS_vdso32.lds = $(CPPFLAGS_vdso.lds)
> -VDSO_LDFLAGS_vdso32.lds = -m32 -Wl,-m,elf_i386 -Wl,-soname=linux-
> gate.so.1
> +VDSO_LDFLAGS_vdso32.lds = -m elf_i386 -soname linux-gate.so.1
>
> # This makes sure the $(obj) subdirectory exists even though vdso32/
> # is not a kbuild sub-make subdirectory.
> @@ -180,13 +176,13 @@ $(obj)/vdso32.so.dbg: FORCE \
> # The DSO images are built using a special linker script.
> #
> quiet_cmd_vdso = VDSO$@
> - cmd_vdso = $(CC)
[PATCH 4.14 09/69] x86: vdso: Use $LD instead of $CC to link
commit 379d98ddf41344273d9718556f761420f4dc80b3 upstream.
The vdso{32,64}.so can fail to link with CC=clang when clang tries to find
a suitable GCC toolchain to link these libraries with.
/usr/bin/ld: arch/x86/entry/vdso/vclock_gettime.o:
access beyond end of merged section (782)
This happens because the host environment leaked into the cross compiler
environment due to the way clang searches for suitable GCC toolchains.
Clang is a retargetable compiler, and each invocation of it must provide
--target= --gcc-toolchain= to allow it to find the
correct binutils for cross compilation. These flags had been added to
KBUILD_CFLAGS, but the vdso code uses CC and not KBUILD_CFLAGS (for various
reasons) which breaks clang's ability to find the correct linker when cross
compiling.
Most of the time this goes unnoticed because the host linker is new enough
to work anyway, or is incompatible and skipped, but this cannot be reliably
assumed.
This change alters the vdso makefile to just use LD directly, which
bypasses clang and thus the searching problem. The makefile will just use
${CROSS_COMPILE}ld instead, which is always what we want. This matches the
method used to link vmlinux.
This drops references to DISABLE_LTO; this option doesn't seem to be set
anywhere, and not knowing what its possible values are, it's not clear how
to convert it from CC to LD flag.
Signed-off-by: Alistair Strachan
Signed-off-by: Thomas Gleixner
Acked-by: Andy Lutomirski
Cc: "H. Peter Anvin"
Cc: Greg Kroah-Hartman
Cc: kernel-t...@android.com
Cc: j...@joelfernandes.org
Cc: Andi Kleen
Link: https://lkml.kernel.org/r/20180803173931.117515-1-astrac...@google.com
Signed-off-by: Nathan Chancellor
Signed-off-by: Sasha Levin
---
arch/x86/entry/vdso/Makefile | 22 +-
1 file changed, 9 insertions(+), 13 deletions(-)
diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile
index 0a550dc5c525..0defcc939ab4 100644
--- a/arch/x86/entry/vdso/Makefile
+++ b/arch/x86/entry/vdso/Makefile
@@ -48,10 +48,8 @@ targets += $(vdso_img_sodbg)
export CPPFLAGS_vdso.lds += -P -C
-VDSO_LDFLAGS_vdso.lds = -m64 -Wl,-soname=linux-vdso.so.1 \
- -Wl,--no-undefined \
- -Wl,-z,max-page-size=4096 -Wl,-z,common-page-size=4096 \
- $(DISABLE_LTO)
+VDSO_LDFLAGS_vdso.lds = -m elf_x86_64 -soname linux-vdso.so.1 --no-undefined \
+ -z max-page-size=4096 -z common-page-size=4096
$(obj)/vdso64.so.dbg: $(src)/vdso.lds $(vobjs) FORCE
$(call if_changed,vdso)
@@ -103,10 +101,8 @@ CFLAGS_REMOVE_vvar.o = -pg
#
CPPFLAGS_vdsox32.lds = $(CPPFLAGS_vdso.lds)
-VDSO_LDFLAGS_vdsox32.lds = -Wl,-m,elf32_x86_64 \
- -Wl,-soname=linux-vdso.so.1 \
- -Wl,-z,max-page-size=4096 \
- -Wl,-z,common-page-size=4096
+VDSO_LDFLAGS_vdsox32.lds = -m elf32_x86_64 -soname linux-vdso.so.1 \
+ -z max-page-size=4096 -z common-page-size=4096
# 64-bit objects to re-brand as x32
vobjs64-for-x32 := $(filter-out $(vobjs-nox32),$(vobjs-y))
@@ -134,7 +130,7 @@ $(obj)/vdsox32.so.dbg: $(src)/vdsox32.lds $(vobjx32s) FORCE
$(call if_changed,vdso)
CPPFLAGS_vdso32.lds = $(CPPFLAGS_vdso.lds)
-VDSO_LDFLAGS_vdso32.lds = -m32 -Wl,-m,elf_i386 -Wl,-soname=linux-gate.so.1
+VDSO_LDFLAGS_vdso32.lds = -m elf_i386 -soname linux-gate.so.1
# This makes sure the $(obj) subdirectory exists even though vdso32/
# is not a kbuild sub-make subdirectory.
@@ -180,13 +176,13 @@ $(obj)/vdso32.so.dbg: FORCE \
# The DSO images are built using a special linker script.
#
quiet_cmd_vdso = VDSO$@
- cmd_vdso = $(CC) -nostdlib -o $@ \
+ cmd_vdso = $(LD) -nostdlib -o $@ \
$(VDSO_LDFLAGS) $(VDSO_LDFLAGS_$(filter %.lds,$(^F))) \
- -Wl,-T,$(filter %.lds,$^) $(filter %.o,$^) && \
+ -T $(filter %.lds,$^) $(filter %.o,$^) && \
sh $(srctree)/$(src)/checkundef.sh '$(NM)' '$@'
-VDSO_LDFLAGS = -fPIC -shared $(call cc-ldoption, -Wl$(comma)--hash-style=both)
\
- $(call cc-ldoption, -Wl$(comma)--build-id) -Wl,-Bsymbolic $(LTO_CFLAGS)
+VDSO_LDFLAGS = -shared $(call ld-option, --hash-style=both) \
+ $(call ld-option, --build-id) -Bsymbolic
GCOV_PROFILE := n
#
--
2.19.1
