Re: [XEN PATCH 3/5] x86: deviate violation of MISRA C Rule 20.12

[Jan Beulich <jbeulich@xxxxxxxx>]

On 01.06.2024 12:16, Nicola Vetrini wrote:
> --- a/xen/arch/x86/include/asm/shared.h
> +++ b/xen/arch/x86/include/asm/shared.h
> @@ -76,6 +76,7 @@ static inline void arch_set_##field(struct vcpu *v,         
> \
>  
>  GET_SET_SHARED(unsigned long, max_pfn)
>  GET_SET_SHARED(xen_pfn_t, pfn_to_mfn_frame_list_list)
> +/* SAF-6-safe Rule 20.12: expansion of macro nmi_reason */
>  GET_SET_SHARED(unsigned long, nmi_reason)

Before we go this route, were alternatives at least considered? Plus
didn't we special-case function-like macros already, when used in
situations where only object-like macros would be expanded anyway?

As to alternatives: nmi_reason() is used in exactly one place.
Dropping the #define and expanding the one use instead would be an
option. I further wonder whether moving the #define-s past the
piece of code you actually modify would also be an option (i.e. the
tool then no longer complaining).

Jan