Re: [PATCH 01/17] misra: add deviation for headers that explicitly avoid guards

[Jan Beulich <jbeulich@xxxxxxxx>]

On 01.07.2024 13:10, Alessandro Zucchelli wrote:
> --- a/docs/misra/safe.json
> +++ b/docs/misra/safe.json
> @@ -68,6 +68,14 @@
>          },
>          {
>              "id": "SAF-8-safe",
> +            "analyser": {
> +                "eclair": "MC3R1.D4.10"
> +            },
> +            "name": "Dir 4.10: headers that leave it up to the caller to 
> include them correctly",
> +            "text": "Headers that deliberatively avoid inclusion guards 
> explicitly leaving responsibility to the caller are allowed."
> +        },
> +        {
> +            "id": "SAF-9-safe",
>              "analyser": {},
>              "name": "Sentinel",
>              "text": "Next ID to be used"

Patch 10 adds another entry here, targeted at headers which are intended to be
possible to include more than once. Both headers here also fit that criteria,
even if right now they aren't used that way (iirc). Do we really need two
SAF-* markers for effectively all the same kind of headers?

> --- a/xen/include/public/arch-x86/cpufeatureset.h
> +++ b/xen/include/public/arch-x86/cpufeatureset.h
> @@ -23,6 +23,7 @@
>   * their XEN_CPUFEATURE() being appropriate in the included context.
>   */
>  
> +/* SAF-8-safe omitted inclusion guard */
>  #ifndef XEN_CPUFEATURE
>  
>  /*
> diff --git a/xen/include/public/errno.h b/xen/include/public/errno.h
> index 5a78a7607c..ccd5023c3a 100644
> --- a/xen/include/public/errno.h
> +++ b/xen/include/public/errno.h
> @@ -17,6 +17,7 @@
>   * will unilaterally #undef XEN_ERRNO().
>   */
>  
> +/* SAF-8-safe omitted inclusion guard */
>  #ifndef XEN_ERRNO
>  
>  /*

Further both of these headers have guards (to cover the default case), so
"omitted" certainly isn't correct. Much like the "name" line in the SAF
entry also isn't quite correct, as in the common case it's not left to
the use sites.

Jan