Re: [PATCH] riscv: Handle zicsr/zifencei issue between gcc and binutils

[Mingzheng Xing]

On 7/31/23 23:24, Conor Dooley wrote:
> On Mon, Jul 31, 2023 at 11:05:11PM +0800, Mingzheng Xing wrote:
> > Binutils-2.38 and GCC-12.1.0 bumped[0][1] the default ISA spec to the newer
> > 20191213 version which moves some instructions from the I extension to the
> > Zicsr and Zifencei extensions. So if one of the binutils and GCC exceeds
> > that version, we should explicitly specifying Zicsr and Zifencei via -march
> > to cope with the new changes. but this only occurs when binutils >= 2.36
> > and GCC >= 11.1.0. It's a different story when binutils < 2.36.
> >
> > binutils-2.36 supports the Zifencei extension[2] and splits Zifencei and
> > Zicsr from I[3]. GCC-11.1.0 is particular[4] because it add support Zicsr
> > and Zifencei extension for -march. binutils-2.35 does not support the
> > Zifencei extension, and does not need to specify Zicsr and Zifencei when
> > working with GCC >= 12.1.0.
> >
> > To make our lives easier, let's relax the check to binutils >= 2.36 in
> > CONFIG_TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI. For the other two cases,
> > where clang < 17 or GCC < 11.1.0, we will deal with them in
> > CONFIG_TOOLCHAIN_NEEDS_OLD_ISA_SPEC.
> >
> > For more information, please refer to:
> > commit 6df2a016c0c8 ("riscv: fix build with binutils 2.38")
> > commit e89c2e815e76 ("riscv: Handle zicsr/zifencei issues between clang and binutils")
> > Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=aed44286efa8ae8717a77d94b51ac3614e2ca6dc [0]
> > Link: https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=98416dbb0a62579d4a7a4a76bab51b5b52fec2cd [1]
> > Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=5a1b31e1e1cee6e9f1c92abff59cdcfff0dddf30 [2]
> > Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=729a53530e86972d1143553a415db34e6e01d5d2 [3]
> > Link: https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=b03be74bad08c382da47e048007a78fa3fb4ef49 [4]
> > Link: https://lore.kernel.org/all/20230308220842.1231003-1-conor@xxxxxxxxxx
> > Link: https://lore.kernel.org/all/20230223220546.52879-1-conor@xxxxxxxxxx
> > Cc: <stable@xxxxxxxxxxxxxxx>
> > Signed-off-by: Mingzheng Xing <xingmingzheng@xxxxxxxxxxx>
> This looks good to me now, thanks! Hopefully the next time we look at
> this code is removing support for binutils 2.35 :)

Thank you for the quick reply.
Hopefully no more "with weeping and gnashing of teeth". ;

> Reviewed-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
>
> Cheers,
> Conor.