Re: [PATCH v5 05/12] x86/mm: add INVLPGB support code

[Rik van Riel]

On Fri, 2025-01-17 at 11:37 +0800, kernel test robot wrote:
> 
> compiler: clang version 19.1.3
> (https://github.com/llvm/llvm-project ab51eccf88f5321e7c60591c5546b25
> 4b6afab99)
> reproduce (this is a W=1 build):
> (https://download.01.org/0day-ci/archive/20250117/202501171121.nQcwVI
> 41-lkp@xxxxxxxxx/reproduce)
> 

> > > arch/x86/include/asm/invlpgb.h:26:49: error: invalid input size
> > > for constraint 'a'
>       26 |         asm volatile(".byte 0x0f, 0x01, 0xfe" : : "a"
> (rax), "c" (ecx), "d" (edx));
>          |                                                        ^
> 

What do I do about this?

It didn't used to complain when we had a named
assembler operator there:

    asm volatile("invlpgb" : : "a" (rax), "c" (ecx), "d" (edx));

However, now that we're using .byte for compatibility
with older binutils, things break with newer llvm?

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