next-20251002: arm64: gcc-8-defconfig: Assembler messages: Error: unknown architectural extension `simd;'

next-20251002: arm64: gcc-8-defconfig: Assembler messages: Error: unknown architectural extension `simd;'

[Naresh Kamboju]

[Resending with typo correction in the subject next tag]

The arm64 defconfig builds failed on the Linux next-20251002 tag build due
to following build warnings / errors with gcc-8 toolchain.

* arm64, build
  - gcc-8-defconfig

First seen on next-20251002
Good: next-20250929
Bad: next-20251002..next-20251003

Regression Analysis:
- New regression? yes
- Reproducibility? yes

Build regression: next-20251002: arm64: gcc-8-defconfig: Assembler
messages: Error: unknown architectural extension `simd;'

Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>

### Build error log
/tmp/cclfMnj9.s: Assembler messages:
/tmp/cclfMnj9.s:656: Error: unknown architectural extension `simd;'
make[8]: *** [scripts/Makefile.build:287:
drivers/net/ethernet/mellanox/mlx5/core/wc.o] Error 1

Suspecting commit,
$ git blame -L 269 drivers/net/ethernet/mellanox/mlx5/core/wc.c
fd8c8216648cd8 (Patrisious Haddad 2025-09-29 00:08:08 +0300 269)
         (".arch_extension simd;\n\t"
fd8c8216648cd net/mlx5: Improve write-combining test reliability for
ARM64 Grace CPUs

## Source
* Kernel version: 6.17.0
* Git tree: https://kernel.googlesource.com/pub/scm/linux/kernel/git/next/linux-next.git
* Git commit: 47a8d4b89844f5974f634b4189a39d5ccbacd81c
* Architectures: arm64
* Toolchains: gcc-8
* Kconfigs: defconfig

## Build
* Build log: https://storage.tuxsuite.com/public/linaro/lkft/builds/33YUHcFKTLSBTOxNIJqF9vJqcxt/build.log
* Build details:
https://regressions.linaro.org/lkft/linux-next-master/next-20251003/build/gcc-8-defconfig/
* Build plan: https://tuxapi.tuxsuite.com/v1/groups/linaro/projects/lkft/builds/33YUHcFKTLSBTOxNIJqF9vJqcxt
* Build link: https://storage.tuxsuite.com/public/linaro/lkft/builds/33YUHcFKTLSBTOxNIJqF9vJqcxt/
* Kernel config:
https://storage.tuxsuite.com/public/linaro/lkft/builds/33YUHcFKTLSBTOxNIJqF9vJqcxt/config

## Steps to reproduce
  - tuxmake --runtime podman --target-arch arm64 --toolchain gcc-8
--kconfig defconfig



--
Linaro LKFT

Re: next-20251002: arm64: gcc-8-defconfig: Assembler messages: Error: unknown architectural extension `simd;'

[Naresh Kamboju]

+ linux-rdma@vger.kernel.org

On Mon, 6 Oct 2025 at 17:00, Naresh Kamboju <naresh.kamboju@linaro.org> wrote:
>
> [Resending with typo correction in the subject next tag]
>
> The arm64 defconfig builds failed on the Linux next-20251002 tag build due
> to following build warnings / errors with gcc-8 toolchain.
>
> * arm64, build
>   - gcc-8-defconfig
>
> First seen on next-20251002
> Good: next-20250929
> Bad: next-20251002..next-20251003
>
> Regression Analysis:
> - New regression? yes
> - Reproducibility? yes
>
> Build regression: next-20251002: arm64: gcc-8-defconfig: Assembler
> messages: Error: unknown architectural extension `simd;'
>
> Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
>
> ### Build error log
> /tmp/cclfMnj9.s: Assembler messages:
> /tmp/cclfMnj9.s:656: Error: unknown architectural extension `simd;'
> make[8]: *** [scripts/Makefile.build:287:
> drivers/net/ethernet/mellanox/mlx5/core/wc.o] Error 1
>
> Suspecting commit,
> $ git blame -L 269 drivers/net/ethernet/mellanox/mlx5/core/wc.c
> fd8c8216648cd8 (Patrisious Haddad 2025-09-29 00:08:08 +0300 269)
>          (".arch_extension simd;\n\t"
> fd8c8216648cd net/mlx5: Improve write-combining test reliability for
> ARM64 Grace CPUs
>
> ## Source
> * Kernel version: 6.17.0
> * Git tree: https://kernel.googlesource.com/pub/scm/linux/kernel/git/next/linux-next.git
> * Git commit: 47a8d4b89844f5974f634b4189a39d5ccbacd81c
> * Architectures: arm64
> * Toolchains: gcc-8
> * Kconfigs: defconfig
>
> ## Build
> * Build log: https://storage.tuxsuite.com/public/linaro/lkft/builds/33YUHcFKTLSBTOxNIJqF9vJqcxt/build.log
> * Build details:
> https://regressions.linaro.org/lkft/linux-next-master/next-20251003/build/gcc-8-defconfig/
> * Build plan: https://tuxapi.tuxsuite.com/v1/groups/linaro/projects/lkft/builds/33YUHcFKTLSBTOxNIJqF9vJqcxt
> * Build link: https://storage.tuxsuite.com/public/linaro/lkft/builds/33YUHcFKTLSBTOxNIJqF9vJqcxt/
> * Kernel config:
> https://storage.tuxsuite.com/public/linaro/lkft/builds/33YUHcFKTLSBTOxNIJqF9vJqcxt/config
>
> ## Steps to reproduce
>   - tuxmake --runtime podman --target-arch arm64 --toolchain gcc-8
> --kconfig defconfig
>
>
>
> --
> Linaro LKFT

Re: next-20251002: arm64: gcc-8-defconfig: Assembler messages: Error: unknown architectural extension `simd;'

[Arnd Bergmann]

On Mon, Oct 6, 2025, at 13:31, Naresh Kamboju wrote:
> + linux-rdma@vger.kernel.org
>
> On Mon, 6 Oct 2025 at 17:00, Naresh Kamboju <naresh.kamboju@linaro.org> wrote:
>> ### Build error log
>> /tmp/cclfMnj9.s: Assembler messages:
>> /tmp/cclfMnj9.s:656: Error: unknown architectural extension `simd;'
>> make[8]: *** [scripts/Makefile.build:287:
>> drivers/net/ethernet/mellanox/mlx5/core/wc.o] Error 1
>>
>> Suspecting commit,
>> $ git blame -L 269 drivers/net/ethernet/mellanox/mlx5/core/wc.c
>> fd8c8216648cd8 (Patrisious Haddad 2025-09-29 00:08:08 +0300 269)
>>          (".arch_extension simd;\n\t"
>> fd8c8216648cd net/mlx5: Improve write-combining test reliability for
>> ARM64 Grace CPUs
>>
>> ## Source
>> * Kernel version: 6.17.0
>> * Git tree: https://kernel.googlesource.com/pub/scm/linux/kernel/git/next/linux-next.git
>> * Git commit: 47a8d4b89844f5974f634b4189a39d5ccbacd81c
>> * Architectures: arm64
>> * Toolchains: gcc-8
>> * Kconfigs: defconfig
>>

Nathan already analyzed the problem and suggested a fix, but I could
not find a patch on the mailing list so far and sent his suggestion
now. Please check

https://lore.kernel.org/all/20251006115640.497169-1-arnd@kernel.org/

    Arnd