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

[Naresh Kamboju]

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.


## 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