linux-kernel - Re: [PATCH v5] riscv: Handle zicsr/zifencei issue between gcc and binutils

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Message-ID: <3ba51c81-7eca-b1b5-c89d-47b292b65641@iscas.ac.cn>
Date:   Fri, 25 Aug 2023 01:46:59 +0800
From:   Mingzheng Xing <xingmingzheng@...as.ac.cn>
To:     Conor Dooley <conor@...nel.org>
Cc:     Conor Dooley <conor.dooley@...rochip.com>,
        patchwork-bot+linux-riscv@...nel.org,
        linux-riscv@...ts.infradead.org, paul.walmsley@...ive.com,
        palmer@...belt.com, aou@...s.berkeley.edu, nathan@...nel.org,
        ndesaulniers@...gle.com, trix@...hat.com, bmeng@...ylab.org,
        guoren@...nel.org, linux-kernel@...r.kernel.org,
        llvm@...ts.linux.dev, stable@...r.kernel.org
Subject: Re: [PATCH v5] riscv: Handle zicsr/zifencei issue between gcc and
 binutils

On 8/25/23 01:33, Conor Dooley wrote:
> On Fri, Aug 25, 2023 at 01:30:36AM +0800, Mingzheng Xing wrote:
>> On 8/24/23 19:32, Mingzheng Xing wrote:
>>> On 8/23/23 21:31, Conor Dooley wrote:
>>>> On Wed, Aug 23, 2023 at 12:51:13PM +0100, Conor Dooley wrote:
>>>>> On Thu, Aug 17, 2023 at 03:20:24PM +0000,
>>>>> patchwork-bot+linux-riscv@...nel.org wrote:
>>>>>> Hello:
>>>>>>
>>>>>> This patch was applied to riscv/linux.git (fixes)
>>>>>> by Palmer Dabbelt <palmer@...osinc.com>:
>>>>>>
>>>>>> On Thu, 10 Aug 2023 00:56:48 +0800 you 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.
>>>>>>>
>>>>>>> [...]
>>>>>> Here is the summary with links:
>>>>>>     - [v5] riscv: Handle zicsr/zifencei issue between gcc and binutils
>>>>>>       https://git.kernel.org/riscv/c/ca09f772ccca
>>>>> *sigh* so this breaks the build for gcc-11 & binutils 2.37 w/
>>>>>      Assembler messages:
>>>>>      Error: cannot find default versions of the ISA extension `zicsr'
>>>>>      Error: cannot find default versions of the ISA extension `zifencei'
>>>>>
>>>>> I'll have a poke later.
>>>> So uh, are we sure that this should not be:
>>>> -       depends on (CC_IS_CLANG && CLANG_VERSION < 170000) ||
>>>> (CC_IS_GCC && GCC_VERSION < 110100)
>>>> +       depends on (CC_IS_CLANG && CLANG_VERSION < 170000) ||
>>>> (CC_IS_GCC && GCC_VERSION <= 110100)
>>>>
>>>> My gcc-11.1 + binutils 2.37 toolchain built from riscv-gnu-toolchain
>>>> doesn't have the default versions & the above diff fixes the build.
>>> I reproduced the error, the combination of gcc-11.1 and
>>> binutils 2.37 does cause errors. What a surprise, since binutils
>>> 2.36 and 2.38 are fine.
>>>
>>> I used git bisect to locate this commit[1] for binutils.
>>> I'll test this diff in more detail later. Thanks!
>>>
>>> [1] https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=f0bae2552db1dd4f1995608fbf6648fcee4e9e0c
>>>
>> Hi, Conor.
>> The above error does originate from link[1] mentioned above, which was
>> resolved in gcc-12.1.0[2], and gcc-11.3.0 made the backport[3].
>> So gcc-11.2.0 combined with binutils 2.37 produces the same error.
>> I think we should do the following diff to fix it:
>> -       depends on (CC_IS_CLANG && CLANG_VERSION < 170000) || (CC_IS_GCC &&
>> GCC_VERSION < 110100)
>> +       depends on (CC_IS_CLANG && CLANG_VERSION < 170000) || (CC_IS_GCC &&
>> GCC_VERSION < 110300)
> That sounds good to me. Can you make that a real patch please?

Okey.
Just a question, I see that the previous patch has been merged
into 6.5-rc7, and now a new fix patch should be sent out based
on that, right?


Best Regards,
Mingzheng.

>
> Thanks for working on it :)