Re: [XEN PATCH v2 02/10] misra: modify deviations for empty and generated headers

[Jan Beulich <jbeulich@xxxxxxxx>]

On 12.09.2023 11:36, Simone Ballarin wrote:
> This patch modifies deviations for Directive 4.10:
> "Precautions shall be taken in order to prevent the contents of
> a header file being included more than once"
> 
> This patch avoids the file-based deviation for empty headers, and
> replaces it with a comment-based one using the format specified in
> docs/misra/safe.json.
> 
> Generated headers are not generally safe against multi-inclusions,
> whether a header is safe depends on the nature of the generated code
> in the header. For that reason, this patch drops the deviation for
> generated headers.
> 
> Signed-off-by: Simone Ballarin <simone.ballarin@xxxxxxxxxxx>
> 
> ---
> Changes in v2:
> - use the format introduced with doc/misra/safe.json instead of
>   a file-based deviation for empty headers
> - remove deviation for generated headers
> ---
>  automation/eclair_analysis/ECLAIR/deviations.ecl | 7 -------
>  docs/misra/safe.json                             | 8 ++++++++
>  xen/arch/arm/efi/runtime.h                       | 1 +
>  xen/include/Makefile                             | 2 +-
>  4 files changed, 10 insertions(+), 8 deletions(-)
> 
> diff --git a/automation/eclair_analysis/ECLAIR/deviations.ecl 
> b/automation/eclair_analysis/ECLAIR/deviations.ecl
> index d8170106b4..9313027af1 100644
> --- a/automation/eclair_analysis/ECLAIR/deviations.ecl
> +++ b/automation/eclair_analysis/ECLAIR/deviations.ecl
> @@ -78,13 +78,6 @@ inline functions."
>  -config=MC3R1.D4.9,macros+={deliberate, "loc(file(api:public))"}
>  -doc_end
>  
> --doc_begin="This header file is autogenerated or empty, therefore it poses no
> -risk if included more than once."
> --file_tag+={empty_header, "^xen/arch/arm/efi/runtime\\.h$"}
> --file_tag+={autogen_headers, 
> "^xen/include/xen/compile\\.h$||^xen/include/generated/autoconf.h$||^xen/include/xen/hypercall-defs.h$"}
> --config=MC3R1.D4.10,reports+={safe, 
> "all_area(all_loc(file(empty_header||autogen_headers)))"}
> --doc_end
> -
>  -doc_begin="Files that are intended to be included more than once do not 
> need to
>  conform to the directive."
>  -config=MC3R1.D4.10,reports+={safe, "first_area(text(^/\\* This file is 
> legitimately included multiple times\\. \\*/$, begin-4))"}
> diff --git a/docs/misra/safe.json b/docs/misra/safe.json
> index db438c9770..e8e200cb0a 100644
> --- a/docs/misra/safe.json
> +++ b/docs/misra/safe.json
> @@ -28,6 +28,14 @@
>          },
>          {
>              "id": "SAF-3-safe",

Noting this, ...

> +            "analyser": {
> +                "eclair": "MC3R1.D4.10"
> +            },
> +            "name": "Dir 4.10: empty headers",
> +            "text": "Empty headers pose no risk if included more than once."
> +        },
> +        {
> +            "id": "SAF-4-safe",
>              "analyser": {},
>              "name": "Sentinel",
>              "text": "Next ID to be used"
> --- a/xen/arch/arm/efi/runtime.h
> +++ b/xen/arch/arm/efi/runtime.h
> @@ -1 +1,2 @@
> +/* SAF-2-safe empty header */
>  /* Placeholder for ARM-specific runtime include/declarations */
> --- a/xen/include/Makefile
> +++ b/xen/include/Makefile
> @@ -53,7 +53,7 @@ cmd_compat_h = \
>      mv -f $@.new $@
>  
>  quiet_cmd_stub_h = GEN     $@
> -cmd_stub_h = echo '/* empty */' >$@
> +cmd_stub_h = echo '/* SAF-2-safe empty header */' >$@

... there's the same off-by-1 here as there was in patch 1.

Jan