Re: next-20250403: x86_64 mwait.h:30:15: error: invalid operand for instruction

[Naresh Kamboju]

+ Uros Bizjak <ubizjak@xxxxxxxxx>

On Thu, 3 Apr 2025 at 15:50, Naresh Kamboju <naresh.kamboju@xxxxxxxxxx> wrote:
>
> Regressions on x86_64 builds tinyconfig, allnoconfig failed with toolchains
> clang-20 and gcc-13 on the Linux next starting from next-20250403.
>
> First seen on the next-20250403
>  Good: next-20250402
>  Bad:  next-20250403
>
> Regressions found on x86_64:
>   - build/gcc-13-tinyconfig
>   - build/gcc-13-allnoconfig
>   - build/clang-20-tinyconfig
>   - build/clang-20-allnoconfig
>
> Regression Analysis:
>  - New regression? Yes
>  - Reproducibility? Yes
>
> Boot regression: x86_64 mwait.h:30:15: error: invalid operand for instruction
>
> Reported-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx>
>
> ## Build log
> In file included from arch/x86/kernel/process.c:36:
> arch/x86/include/asm/mwait.h:30:15: error: invalid operand for instruction
>    30 |         asm volatile("monitor %0, %1, %2" :: "a" (eax), "c"
> (ecx), "d" (edx));
>       |                      ^
> <inline asm>:1:16: note: instantiated into assembly here
>     1 |         monitor %rax, %ecx, %edx
>       |                       ^~~~~
> In file included from arch/x86/kernel/process.c:36:
> arch/x86/include/asm/mwait.h:95:15: error: instruction requires: Not 64-bit mode
>    95 |         asm volatile("sti; mwait %0, %1" :: "a" (eax), "c" (ecx));
>       |                      ^
> <inline asm>:1:7: note: instantiated into assembly here
>     1 |         sti; mwait %eax, %ecx
>       |              ^
> 2 errors generated.

Anders bisected this to,

# first bad commit:
   [cd3b85b27542968198e3d588a2bc0591930ee2ee]
   x86/idle: Use MONITOR and MWAIT mnemonics in <asm/mwait.h>


>
> ## Source
> * Kernel version: 6.14.0
> * Git tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
> * Git sha: f0a16f5363325cc8d9382471cdc7b654c53254c9
> * Git describe: next-20250403
> * Project details:
> https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20250403/
> * Architectures: x86_64
> * Toolchains: clang-20, gcc-13
> * Kconfigs: tinyconfig, allnoconfig, lkftconfig
>
> ## Build
> * Build log: https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20250403/testrun/27871165/suite/build/test/clang-20-allnoconfig/log
> * Build history:
> https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20250403/testrun/27871165/suite/build/test/clang-20-allnoconfig/history/
> * Build details:
> https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20250403/testrun/27871165/suite/build/test/clang-20-allnoconfig/
> * Build link: https://storage.tuxsuite.com/public/linaro/lkft/builds/2vCvvmy6fhzm3aMcptKXHvRi4Bp/
> * Kernel config:
> https://storage.tuxsuite.com/public/linaro/lkft/builds/2vCvvmy6fhzm3aMcptKXHvRi4Bp/config
>
> --
> Linaro LKFT
> https://lkft.linaro.org

Links,
 - https://lore.kernel.org/all/CA+G9fYtzOxx1YWz2X4UYqvxB2vg7ptz6axmz-5HFLD9ieSjURw@xxxxxxxxxxxxxx/

- Naresh