Re: [linux-next:master 3665/11714] {standard input}:2644: Error: pcrel offset for branch to .LS0015 too far (0x3e)

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On Wed, Jun 23, 2021 at 4:59 PM Feng Tang <feng.tang@xxxxxxxxx> wrote:
>
> Add linux-csky list and originally cced people and replace the linux-mm
> with linux-kbuild list, which match the discussion better and avoid
> email noise for mm people.
>
> On Tue, Jun 22, 2021 at 05:48:18PM +0800, Tang, Feng wrote:
> > On Tue, Jun 22, 2021 at 09:49:05AM +0800, kernel test robot wrote:
> > > tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> > > head:   889bab4c367a0ef58208fd80fafa74bb6e2dca26
> > > commit: cf536e185869d4815d506e777bcca6edd9966a6e [3665/11714] Makefile: extend 32B aligned debug option to 64B aligned
> > > config: csky-randconfig-c024-20210622 (attached as .config)
> > > compiler: csky-linux-gcc (GCC) 9.3.0
> > > 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
> > >         # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=cf536e185869d4815d506e777bcca6edd9966a6e
> > >         git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
> > >         git fetch --no-tags linux-next master
> > >         git checkout cf536e185869d4815d506e777bcca6edd9966a6e
> > >         # save the attached .config to linux build tree
> > >         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=csky
>
> > Thanks for the report.
> >
> > I just reproduced the issue locally, with similar log:
> >
> >   CC      drivers/target/target_core_sbc.o
> > {standard input}: Assembler messages:
> > {standard input}:2644: Error: pcrel offset for branch to .LS0015 too far (0x3e)
> > {standard input}:2653: Error: pcrel offset for branch to .LS0015 too far (0x34)
> > {standard input}:2659: Error: pcrel offset for branch to .LS0015 too far (0x2c)
> > make[2]: *** [scripts/Makefile.build:272: drivers/target/target_core_sbc.o] Error 1
> > m
> >
> > And when I changed the function align option from 64 to 32, the
> > compilation did pass, so this looks to be related with the alignment
> > option.
> >
> > I'm not very familiar with compiler, and will try to check more.
>
> I did some check and found the error info comes from the assembler
> for 'csky' in binutils' gas/config/tc-csky.c, and I could hardly
> dive deeper into the code as limited by my knowledge.
>
>
> > I know it works on x86_64, but don't know how about other
> > architectures, and if 'csky' is the only not working one, one
> > workaround I can think of is to add kconfig dependency for !csky
>
> I reused the 0day's reproduce process, and tried on arm64, powerpc64,
> and arc, the kernel compilation all succeeded. So maybe we can
> add some dependency for this debug option like:
>
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index 3cf48998a374..eb035b31657f 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -415,7 +415,8 @@ config SECTION_MISMATCH_WARN_ONLY
>           If unsure, say Y.
>
>  config DEBUG_FORCE_FUNCTION_ALIGN_64B
> -       bool "Force all function address 64B aligned" if EXPERT
> +       bool "Force all function address 64B aligned"
> +       depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC)
>         help
>           There are cases that a commit from one domain changes the function
>           address alignment of other domains, and cause magic performance
>
> Any comments? thanks!
Have tried riscv32? I don't think csky is the only problem.

Assembler just follows gcc backend result and also depends on ISA
design. Our condition branch seems not far enough.

Cc: xianmiao_qu@xxxxxxxxx

>
> - Feng
>
> > Thanks,
> > Feng
> >
> >



-- 
Best Regards
 Guo Ren

ML: https://lore.kernel.org/linux-csky/



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