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From:   Nick Desaulniers <ndesaulniers@google.com>
Date:   Wed, 14 Jun 2023 12:40:28 -0400
Message-ID: <CAKwvOd=yg5GE8eF5bFY4t2S-0Od3smH9iRB+2Ctkg=+WXM97ig@mail.gmail.com>
Subject: Re: ld.lld: error: relocation R_RISCV_HI20 cannot be used against
 symbol 'misaligned_access_speed'; recompile with -fPIC
To:     Alexandre Ghiti <alexghiti@rivosinc.com>
Cc:     kernel test robot <lkp@intel.com>, llvm@lists.linux.dev,
        oe-kbuild-all@lists.linux.dev, linux-kernel@vger.kernel.org,
        Palmer Dabbelt <palmer@rivosinc.com>
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On Tue, Jun 13, 2023 at 4:17=E2=80=AFAM Alexandre Ghiti <alexghiti@rivosinc=
.com> wrote:
>
> On Sun, Jun 11, 2023 at 2:11=E2=80=AFAM kernel test robot <lkp@intel.com>=
 wrote:
> >
> > tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.=
git master
> > head:   022ce8862dff83c859089cd14bc4dca0733e2f90
> > commit: 8dc2a7e8027fbeca0c7df81d4c82e735a59b5741 riscv: Fix relocatable=
 kernels with early alternatives using -fno-pie
> > date:   10 days ago
> > config: riscv-randconfig-r022-20230611 (https://download.01.org/0day-ci=
/archive/20230611/202306110855.7TlBCIzI-lkp@intel.com/config)
> > compiler: clang version 16.0.4 (https://github.com/llvm/llvm-project.gi=
t ae42196bc493ffe877a7e3dff8be32035dea4d07)
> > reproduce (this is a W=3D1 build):
> >         mkdir -p ~/bin
> >         wget https://raw.githubusercontent.com/intel/lkp-tests/master/s=
bin/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://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linu=
x.git/commit/?id=3D8dc2a7e8027fbeca0c7df81d4c82e735a59b5741
> >         git remote add linus https://git.kernel.org/pub/scm/linux/kerne=
l/git/torvalds/linux.git
> >         git fetch --no-tags linus master
> >         git checkout 8dc2a7e8027fbeca0c7df81d4c82e735a59b5741
> >         # save the config file
> >         mkdir build_dir && cp config build_dir/.config
> >         COMPILER_INSTALL_PATH=3D$HOME/0day COMPILER=3Dclang ~/bin/make.=
cross W=3D1 O=3Dbuild_dir ARCH=3Driscv olddefconfig
> >         COMPILER_INSTALL_PATH=3D$HOME/0day COMPILER=3Dclang ~/bin/make.=
cross W=3D1 O=3Dbuild_dir ARCH=3Driscv SHELL=3D/bin/bash
> >
> > If you fix the issue in a separate patch/commit (i.e. not just a new ve=
rsion of
> > the same patch/commit), kindly add following tags
> > | Reported-by: kernel test robot <lkp@intel.com>
> > | Closes: https://lore.kernel.org/oe-kbuild-all/202306110855.7TlBCIzI-l=
kp@intel.com/
> >
> > All errors (new ones prefixed by >>):
> >
> > >> ld.lld: error: relocation R_RISCV_HI20 cannot be used against symbol=
 'misaligned_access_speed'; recompile with -fPIC
> >    >>> defined in vmlinux.a(arch/riscv/kernel/cpufeature.o)
> >    >>> referenced by errata.c:42 (arch/riscv/errata/thead/errata.c:42)
> >    >>>               arch/riscv/errata/thead/errata.o:(thead_feature_pr=
obe_func) in archive vmlinux.a
> > --
> > >> ld.lld: error: relocation R_RISCV_LO12_I cannot be used against symb=
ol 'misaligned_access_speed'; recompile with -fPIC
> >    >>> defined in vmlinux.a(arch/riscv/kernel/cpufeature.o)
> >    >>> referenced by errata.c:42 (arch/riscv/errata/thead/errata.c:42)
> >    >>>               arch/riscv/errata/thead/errata.o:(thead_feature_pr=
obe_func) in archive vmlinux.a
> > --
> > >> ld.lld: error: relocation R_RISCV_HI20 cannot be used against symbol=
 'riscv_cbom_block_size'; recompile with -fPIC
> >    >>> defined in vmlinux.a(arch/riscv/mm/cacheflush.o)
> >    >>> referenced by errata.c:42 (arch/riscv/errata/thead/errata.c:42)
> >    >>>               arch/riscv/errata/thead/errata.o:(thead_errata_pat=
ch_func) in archive vmlinux.a
> > --
> > >> ld.lld: error: relocation R_RISCV_LO12_S cannot be used against symb=
ol 'riscv_cbom_block_size'; recompile with -fPIC
> >    >>> defined in vmlinux.a(arch/riscv/mm/cacheflush.o)
> >    >>> referenced by errata.c:42 (arch/riscv/errata/thead/errata.c:42)
> >    >>>               arch/riscv/errata/thead/errata.o:(thead_errata_pat=
ch_func) in archive vmlinux.a
> > --
> > >> ld.lld: error: relocation R_RISCV_HI20 cannot be used against symbol=
 '__per_cpu_offset'; recompile with -fPIC
> >    >>> defined in vmlinux.a(mm/percpu.o)
> >    >>> referenced by errata.c:42 (arch/riscv/errata/thead/errata.c:42)
> >    >>>               arch/riscv/errata/thead/errata.o:(thead_feature_pr=
obe_func) in archive vmlinux.a
> > --
> > >> ld.lld: error: relocation R_RISCV_LO12_I cannot be used against symb=
ol '__per_cpu_offset'; recompile with -fPIC
> >    >>> defined in vmlinux.a(mm/percpu.o)
> >    >>> referenced by errata.c:42 (arch/riscv/errata/thead/errata.c:42)
> >    >>>               arch/riscv/errata/thead/errata.o:(thead_feature_pr=
obe_func) in archive vmlinux.a
> >
>
> So I looked into those errors, the config is basically =3D RELOCATABLE +
> MEDLOW - EARLY_ALTERNATIVES. Then errata/thead is not compiled as

Thanks for taking a look.  Shouldn't CONFIG_RELOCATABLE be setting
-fPIC? If so, why is LLD complaining about -fPIC not being used?

arch/riscv/Makefile sets -fPIE if CONFIG_RELOCATABLE =3D=3D y.

Is it possible that -fpie was dropped for these object files, or
-fno-pic or -fno-pie was added to the cflags for these object files
somehow?

I've filed
https://github.com/ClangBuiltLinux/linux/issues/1872
to track this.

> medany, which makes sense since we only need this code to be medany
> when EARLY_ALTERNATIVES is enabled (because the code would be executed
> with mmu off, which is not the case here).
>
> I can fix those errors by adding the medany flag, but I'm not sure
> actually we want to do that since we do not need it and gcc does not
> complain: any idea?
>
> Alex
>
>
>
> > --
> > 0-DAY CI Kernel Test Service
> > https://github.com/intel/lkp-tests/wiki
>


--=20
Thanks,
~Nick Desaulniers