linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Nathan Chancellor <natechancellor@gmail.com>
To: Nick Desaulniers <ndesaulniers@google.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>,
	Nicholas Piggin <npiggin@gmail.com>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Joe Lawrence <joe.lawrence@redhat.com>,
	Christophe Leroy <christophe.leroy@c-s.fr>,
	linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
	clang-built-linux@googlegroups.com,
	Kees Cook <keescook@chromium.org>,
	Fangrui Song <maskray@google.com>
Subject: Re: [PATCH 0/2] link vdso with linker
Date: Tue, 1 Sep 2020 22:21:23 -0700	[thread overview]
Message-ID: <20200902052123.GA2687902@ubuntu-n2-xlarge-x86> (raw)
In-Reply-To: <20200901222523.1941988-1-ndesaulniers@google.com>

On Tue, Sep 01, 2020 at 03:25:21PM -0700, Nick Desaulniers wrote:
> Kees Cook is working on series that adds --orphan-section=warn to arm,
> arm64, and x86.  I noticed that ppc vdso were still using cc-ldoption
> for these which I removed.  It seems this results in that flag being
> silently dropped.
> 
> I'm very confident with the first patch, but the second needs closer
> review around the error mentioned below the fold related to the .got
> section.
> 
> Nick Desaulniers (2):
>   powerpc/vdso64: link vdso64 with linker
>   powerpc/vdso32: link vdso64 with linker
> 
>  arch/powerpc/include/asm/vdso.h         | 17 ++---------------
>  arch/powerpc/kernel/vdso32/Makefile     |  7 +++++--
>  arch/powerpc/kernel/vdso32/vdso32.lds.S |  3 ++-
>  arch/powerpc/kernel/vdso64/Makefile     |  8 ++++++--
>  arch/powerpc/kernel/vdso64/vdso64.lds.S |  1 -
>  5 files changed, 15 insertions(+), 21 deletions(-)
> 
> -- 
> 2.28.0.402.g5ffc5be6b7-goog
> 

ppc44x_defconfig and powernv_defconfig start failing with this series
when LD=ld.lld is used.


$ make -skj"$(nproc)" ARCH=powerpc CROSS_COMPILE=powerpc-linux-gnu- LLVM=1 O=out/ppc32 distclean ppc44x_defconfig uImage
ld.lld: error: relocation R_PPC_REL16_LO cannot be used against symbol __kernel_datapage_offset; recompile with -fPIC
>>> defined in arch/powerpc/kernel/vdso32/datapage.o
>>> referenced by arch/powerpc/kernel/vdso32/gettimeofday.o:(__kernel_gettimeofday)

ld.lld: error: relocation R_PPC_REL16_LO cannot be used against symbol __kernel_datapage_offset; recompile with -fPIC
>>> defined in arch/powerpc/kernel/vdso32/datapage.o
>>> referenced by arch/powerpc/kernel/vdso32/gettimeofday.o:(__kernel_clock_gettime)

ld.lld: error: relocation R_PPC_REL16_LO cannot be used against symbol __kernel_datapage_offset; recompile with -fPIC
>>> defined in arch/powerpc/kernel/vdso32/datapage.o
>>> referenced by arch/powerpc/kernel/vdso32/gettimeofday.o:(__kernel_clock_getres)

ld.lld: error: relocation R_PPC_REL16_LO cannot be used against symbol __kernel_datapage_offset; recompile with -fPIC
>>> defined in arch/powerpc/kernel/vdso32/datapage.o
>>> referenced by arch/powerpc/kernel/vdso32/gettimeofday.o:(__kernel_time)
...


$ make -skj"$(nproc)" ARCH=powerpc CROSS_COMPILE=powerpc64le-linux-gnu- LLVM=1 O=out/ppc64le distclean powernv_defconfig zImage.epapr
ld.lld: error: relocation R_PPC64_REL16_LO cannot be used against symbol __kernel_datapage_offset; recompile with -fPIC
>>> defined in arch/powerpc/kernel/vdso64/datapage.o
>>> referenced by arch/powerpc/kernel/vdso64/gettimeofday.o:(__kernel_gettimeofday)

ld.lld: error: relocation R_PPC64_REL16_LO cannot be used against symbol __kernel_datapage_offset; recompile with -fPIC
>>> defined in arch/powerpc/kernel/vdso64/datapage.o
>>> referenced by arch/powerpc/kernel/vdso64/gettimeofday.o:(__kernel_clock_gettime)

ld.lld: error: relocation R_PPC64_REL16_LO cannot be used against symbol __kernel_datapage_offset; recompile with -fPIC
>>> defined in arch/powerpc/kernel/vdso64/datapage.o
>>> referenced by arch/powerpc/kernel/vdso64/gettimeofday.o:(__kernel_clock_getres)

ld.lld: error: relocation R_PPC64_REL16_LO cannot be used against symbol __kernel_datapage_offset; recompile with -fPIC
>>> defined in arch/powerpc/kernel/vdso64/datapage.o
>>> referenced by arch/powerpc/kernel/vdso64/gettimeofday.o:(__kernel_time)

ld.lld: error: relocation R_PPC64_REL16_LO cannot be used against symbol __kernel_datapage_offset; recompile with -fPIC
>>> defined in arch/powerpc/kernel/vdso64/datapage.o
>>> referenced by arch/powerpc/kernel/vdso64/cacheflush.o:(__kernel_sync_dicache)
...


We need Fangrui's patch to fix ppc44x_defconfig:

https://lore.kernel.org/lkml/20200205005054.k72fuikf6rwrgfe4@google.com/

That exact same fix is needed in arch/powerpc/kernel/vdso64/datapage.S
to fix powernv_defconfig.

Cheers,
Nathan

      parent reply	other threads:[~2020-09-02  5:21 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-01 22:25 [PATCH 0/2] link vdso with linker Nick Desaulniers
2020-09-01 22:25 ` [PATCH 1/2] powerpc/vdso64: link vdso64 " Nick Desaulniers
2020-09-02 12:14   ` Michael Ellerman
2020-09-02 17:41     ` Nick Desaulniers
2020-09-02 18:02       ` Christophe Leroy
2021-04-22 22:44         ` Nick Desaulniers
2021-04-23  7:40           ` Christophe Leroy
2021-04-23 17:18           ` Christophe Leroy
2022-03-02 16:48   ` Christophe Leroy
2020-09-01 22:25 ` [PATCH 2/2] powerpc/vdso32: " Nick Desaulniers
2020-09-02  2:58   ` Kees Cook
2020-09-02  6:46   ` Christophe Leroy
2020-09-02 14:14     ` Segher Boessenkool
2020-09-02 15:43       ` Christophe Leroy
2020-09-02 16:57         ` Segher Boessenkool
2020-09-02  7:56   ` Christophe Leroy
2020-09-02 10:16   ` Christophe Leroy
2020-09-02  5:21 ` Nathan Chancellor [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200902052123.GA2687902@ubuntu-n2-xlarge-x86 \
    --to=natechancellor@gmail.com \
    --cc=benh@kernel.crashing.org \
    --cc=christophe.leroy@c-s.fr \
    --cc=clang-built-linux@googlegroups.com \
    --cc=joe.lawrence@redhat.com \
    --cc=keescook@chromium.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linuxppc-dev@lists.ozlabs.org \
    --cc=maskray@google.com \
    --cc=mpe@ellerman.id.au \
    --cc=ndesaulniers@google.com \
    --cc=npiggin@gmail.com \
    --cc=paulus@samba.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).