Re: [PATCH 1/6] x86/PV: adjust APPEND_CALL() to comply to Misra rule 18.2

[Dmytro Prokopchuk1 <dmytro_prokopchuk1@xxxxxxxx>]

On 9/9/26 15:59, Jan Beulich wrote:
> While casting to pointer types may be more natural there, the subtraction
> then ends up violating "Subtraction between pointers shall only be applied
> to pointers that address elements of the same array". Use long arithmetic
> instead.
> 
> No functional change intended.
> 
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
> ---
> Depends on "Eclair: relax long <-> function-pointer conversion deviation"
> to not introduce other violations in turn.
> 
> --- a/xen/arch/x86/pv/emul-priv-op.c
> +++ b/xen/arch/x86/pv/emul-priv-op.c
> @@ -92,7 +92,8 @@ static io_emul_stub_t *io_emul_stub_setu
>   #define APPEND_BUFF(b) ({ memcpy(p, b, sizeof(b)); p += sizeof(b); })
>   #define APPEND_CALL(f)                                                  \
>       ({                                                                  \
> -        long disp = (void *)(f) - (stub_va + (p - ctxt->io_emul_stub) + 5); \
> +        long disp = (long)(f) -                                         \
> +                    ((long)stub_va + (p - ctxt->io_emul_stub) + 5);     \
>           BUG_ON((int32_t)disp != disp);                                  \
>           *p++ = 0xe8;                                                    \
>           *(int32_t *)p = disp; p += 4;                                   \

LGTM.

Reviewed-by: Dmytro Prokopchuk <dmytro_prokopchuk1@xxxxxxxx>