Re: [PATCH] x86/extable: include asm/processor.h for cpu_relax()

[Dmytro Maluka]

On Fri, Apr 18, 2025 at 02:12:03PM +0200, Borislav Petkov wrote:
> On Fri, Apr 18, 2025 at 11:57:00AM +0000, Dmytro Maluka wrote:
> > Include asm/processor.h to prevents compilation failures due to implicit
> > declaration of cpu_relax() in ex_handler_msr_mce() when compiling with
> > CONFIG_X86_MCE disabled.
> 
> Builds fine here:
> 
> $ grep X86_MCE .config
> # CONFIG_X86_MCE is not set
> 
> $ make -j...
> ...
> 
>   OBJCOPY arch/x86/boot/setup.bin
>   BUILD   arch/x86/boot/bzImage
> Kernel: arch/x86/boot/bzImage is ready  (#1)
> $

Yeah, I meant precisely: when compiling with CONFIG_X86_MCE disabled and
some code enabled that includes asm/extable.h without prior including
asm/processor.h.

I encountered that with the out-of-tree-yet code [1] (which is a part of
a prototype implementation of pKVM on x86) which includes asm/sections.h
which includes asm/extable.h.

[1] https://github.com/intel-staging/pKVM-IA/blob/pvVMCS-POC-v6.12/arch/x86/kvm/pkvm/smp.c