Re: [PATCH v1] riscv: Using TOOLCHAIN_HAS_ZIHINTPAUSE marco replace zihintpause

Minda Chen
2023-08-02T08:18:46Z

On 2023/8/2 15:48, Conor Dooley wrote:
> On Wed, Aug 02, 2023 at 03:32:15PM +0800, Minda Chen wrote:
>>
>>
>> On 2023/8/2 14:54, Conor Dooley wrote:
>> > Hey Minda,
>> >
>> > On Wed, Aug 02, 2023 at 02:42:15PM +0800, Minda Chen wrote:
>> >> Actually it is a part of Conor's
>> >> commit aae538cd03bc ("riscv: fix detection of toolchain
>> >> Zihintpause support").
>> >> It is looks like a merge issue.
>> >
>> > Yup, spot on.
>> >
>> >> Samuel's
>> >> commit 0b1d60d6dd9e ("riscv: Fix build with
>> >> CONFIG_CC_OPTIMIZE_FOR_SIZE=y") do not base on Conor's commit and
>> >> revert to __riscv_zihintpause. So this patch can fix it.
>> >>
>> >> Signed-off-by: Minda Chen <minda.chen@starfivetech.com>
>> >
>> > Did you actually manage to trigger this, or was this by inspection?
>> > clang-15 + binutils 2.35 was, IIRC, how we spotted this because that's
>> > what the clang-built-linux CI uses to test the LTS kernels from before
>> > LLVM's IAS was supported for RISC-V. Seemingly all that needs to be
>> > satisfied there is that zihintpause doesn't appear in -march so this has
>> > gone unnoticed.
>> >
>> > Fixes: 3c349eacc559 ("Merge patch "riscv: Fix build with CONFIG_CC_OPTIMIZE_FOR_SIZE=y"")
>> > Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
>> >
>> > Thanks,
>> > Conor.
>> >
>> Thanks, Conor. I found this just by inspection. I found a issue that vdso.so call cpu_relax
>> cause application core dump in kernel 6.1.31. I need Samuel'patch to fix this. And I search the log
>> of processor.h found this issue.
>
> That doesn't look like it is fixed in later stable kernels (we are at
> 6.1.42-rcN right now I think). It sounds we should ask Greg to backport
> 0b1d60d6dd9e ("riscv: Fix build with CONFIG_CC_OPTIMIZE_FOR_SIZE=y")
> to 6.1. Does that make sense to you?
Yes. 6.1 is lts kernel. Starfive will use this kernel for a long time. Thanks.