From: Nathan Chancellor <nathan@kernel.org>
To: kernel test robot <lkp@intel.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
Albert Ou <aou@eecs.berkeley.edu>,
kbuild-all@lists.01.org, clang-built-linux@googlegroups.com,
linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] riscv: Use $(LD) instead of $(CC) to link vDSO
Date: Fri, 26 Mar 2021 16:58:39 -0700 [thread overview]
Message-ID: <20210326235839.zgfvmtfxrb3hy6i4@archlinux-ax161> (raw)
In-Reply-To: <202103262325.9ejJuOqf-lkp@intel.com>
On Sat, Mar 27, 2021 at 12:05:34AM +0800, kernel test robot wrote:
> Hi Nathan,
>
> I love your patch! Yet something to improve:
>
> [auto build test ERROR on linus/master]
> [also build test ERROR on v5.12-rc4 next-20210326]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch]
>
> url: https://github.com/0day-ci/linux/commits/Nathan-Chancellor/riscv-Use-LD-instead-of-CC-to-link-vDSO/20210326-055421
> base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 002322402dafd846c424ffa9240a937f49b48c42
> config: riscv-randconfig-r032-20210326 (attached as .config)
> compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project f490a5969bd52c8a48586f134ff8f02ccbb295b3)
> reproduce (this is a W=1 build):
> wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> chmod +x ~/bin/make.cross
> # install riscv cross compiling tool for clang build
> # apt-get install binutils-riscv64-linux-gnu
> # https://github.com/0day-ci/linux/commit/dfdcaf93f40f0d15ffc3f25128442c1688e612d6
> git remote add linux-review https://github.com/0day-ci/linux
> git fetch --no-tags linux-review Nathan-Chancellor/riscv-Use-LD-instead-of-CC-to-link-vDSO/20210326-055421
> git checkout dfdcaf93f40f0d15ffc3f25128442c1688e612d6
> # save the attached .config to linux build tree
> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=riscv
For the record, I tried to use this script to reproduce but it has a
couple of bugs:
1. It does not download the right version of clang. This report says
that it is clang-13 but the one that the script downloaded is clang-12.
2. It does not download it to the right location. The script expects
~/0day/clang-latest but it is downloaded to ~/0day/clang it seems. I
symlinked it to get around it.
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
>
> All errors (new ones prefixed by >>):
>
> >> riscv64-linux-gnu-objcopy: 'arch/riscv/kernel/vdso/vdso.so.dbg': No such file
This error only occurs because of errors before it that are not shown
due to a denylist:
ld.lld: error: arch/riscv/kernel/vdso/rt_sigreturn.o:(.text+0x0): relocation R_RISCV_ALIGN requires unimplemented linker relaxation; recompile with -mno-relax
ld.lld: error: arch/riscv/kernel/vdso/getcpu.o:(.text+0x0): relocation R_RISCV_ALIGN requires unimplemented linker relaxation; recompile with -mno-relax
ld.lld: error: arch/riscv/kernel/vdso/flush_icache.o:(.text+0x0): relocation R_RISCV_ALIGN requires unimplemented linker relaxation; recompile with -mno-relax
My patch only adds another occurrence of this error because we move from
$(CC)'s default linker (in clang's case, ld.bfd) to $(LD), which in the
case of 0day appears to be ld.lld. ld.lld should not be used with RISC-V
in its current form due to errors of this nature, which happen without
my patch as well:
https://github.com/ClangBuiltLinux/linux/issues/1020
Linker relaxation in ld.lld for RISC-V is an ongoing debate/process.
Please give RISC-V the current treatment as s390 with ld.lld for the
time being to get meaningful reports. We will reach out once that issue
has been resolved.
TL;DR: Patch exposes existing issue with LD=ld.lld that would have
happened without it in different areas, the report can be ignored.
Cheers!
Nathan
next prev parent reply other threads:[~2021-03-26 23:59 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-25 21:51 [PATCH] riscv: Use $(LD) instead of $(CC) to link vDSO Nathan Chancellor
2021-03-26 16:05 ` kernel test robot
2021-03-26 23:58 ` Nathan Chancellor [this message]
2021-03-27 1:56 ` Fangrui Song
2021-03-29 7:41 ` [kbuild-all] " Rong Chen
2021-03-27 2:02 ` Fangrui Song
2021-04-11 21:20 ` Palmer Dabbelt
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