Re: [PATCH 2/6] x86/alternatives: adjust _apply_alternatives() to comply to Misra rule 18.2

[Dmytro Prokopchuk1 <dmytro_prokopchuk1@epam.com>]

On 9/9/26 15:59, Jan Beulich wrote:
> While avoiding casts would be preferable here, the subtraction 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@suse.com>
> 
> --- a/xen/arch/x86/alternative.c
> +++ b/xen/arch/x86/alternative.c
> @@ -342,13 +342,13 @@ static int init_or_livepatch _apply_alte
>   
>           /* 0xe8/0xe9 are relative branches; fix the offset. */
>           if ( a->repl_len >= 5 && (*buf & 0xfe) == 0xe8 )
> -            *(int32_t *)(buf + 1) += repl - orig;
> +            *(int32_t *)(buf + 1) += (long)repl - (long)orig;
>           else if ( IS_ENABLED(CONFIG_RETURN_THUNK) &&
>                     a->repl_len > 5 && buf[a->repl_len - 5] == 0xe9 &&
>                     ((long)repl + a->repl_len +
>                      *(int32_t *)(buf + a->repl_len - 4) ==
>                      (long)__x86_return_thunk) )
> -            *(int32_t *)(buf + a->repl_len - 4) += repl - orig;
> +            *(int32_t *)(buf + a->repl_len - 4) += (long)repl - (long)orig;
>   
>           a->priv = 1;
>   

Reviewed-by: Dmytro Prokopchuk <dmytro_prokopchuk1@epam.com>

BR, Dmytro.