Re: [PATCH v5] automation/eclair: update configuration of D4.10

[Nicola Vetrini <nicola.vetrini@bugseng.com>]

On 2025-06-21 04:19, Stefano Stabellini wrote:
> MISRA C Directive 4.10 states that "Precautions shall be taken in order
> to prevent the contents of a header file being included more than
> once".
> 
> Add a SAF tag to the existing comment on top of cpufeatures.h.

You say this, but technically the comment is not a SAF comment, just a 
regular one that is interpreted to tailor the guideline.

> Add a header inclusion guard to compile.h.
> 
> Update ECLAIR configuration to:
> - extend existing deviation to other comments explicitly saying a file
>   is intended for multiple inclusion;
> - extend existing deviation to other autogenerated files;
> - tag the guidelines as clean.
> 
> Update deviations.rst accordingly.
> 
> Signed-off-by: Federico Serafini <federico.serafini@bugseng.com>
> Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com>
> ---
> Changes in v5:
> - add missing spaces in in-code comment
> ---
>  automation/eclair_analysis/ECLAIR/deviations.ecl | 11 +++++++----
>  automation/eclair_analysis/ECLAIR/tagging.ecl    |  1 +
>  docs/misra/deviations.rst                        | 12 ++++++++++++
>  xen/arch/x86/include/asm/cpufeatures.h           |  8 +++++---
>  xen/include/xen/compile.h.in                     |  3 +++
>  xen/tools/process-banner.sed                     |  5 +++++
>  6 files changed, 33 insertions(+), 7 deletions(-)
> 
> diff --git a/automation/eclair_analysis/ECLAIR/deviations.ecl 
> b/automation/eclair_analysis/ECLAIR/deviations.ecl
> index 9c67358d46..3b5bc87e1d 100644
> --- a/automation/eclair_analysis/ECLAIR/deviations.ecl
> +++ b/automation/eclair_analysis/ECLAIR/deviations.ecl
> @@ -72,11 +72,14 @@ they are not instances of commented-out code."
>  -config=MC3A2.D4.3,reports+={deliberate, 
> "any_area(any_loc(file(arm64_bitops))&&context(name(int_clear_mask16)))"}
>  -doc_end
> 
> --doc_begin="Files that are intended to be included more than once do 
> not need to
> -conform to the directive."
> +-doc_begin="Files that are intended to be included more than once (and 
> have
> +a comment that says this explicitly) do not need to conform to the 
> directive."
>  -config=MC3A2.D4.10,reports+={safe, "first_area(text(^/\\* This file 
> is intended to be included multiple times\\. \\*/$, begin-4))"}

[1] Here

> --config=MC3A2.D4.10,reports+={safe, "first_area(text(^/\\* Generated 
> file, do not edit! \\*/$, begin-3))"}
> --config=MC3A2.D4.10,reports+={safe, 
> "all_area(all_loc(file(^xen/include/generated/autoconf.h$)))"}
> +-config=MC3A2.D4.10,reports+={safe, "first_area(text(^/\\* Generated 
> file, do not edit! \\*/$, begin-3...begin-2))"}
> +-doc_end
> +
> +-doc_begin="Autogenerated files that do not need to conform to the 
> directive."
> +-config=MC3A2.D4.10,reports+={safe, 
> "all_area(all_loc(file(^xen/include/generated/autoconf\\.h$)))"}
>  -doc_end
> 
>  -doc_begin="Including multiple times a .c file is safe because every 
> function or data item
> diff --git a/automation/eclair_analysis/ECLAIR/tagging.ecl 
> b/automation/eclair_analysis/ECLAIR/tagging.ecl
> index f9da5d5f4d..b95f07feb0 100644
> --- a/automation/eclair_analysis/ECLAIR/tagging.ecl
> +++ b/automation/eclair_analysis/ECLAIR/tagging.ecl
> @@ -23,6 +23,7 @@
>  "MC3A2.D1.1||
>  MC3A2.D2.1||
>  MC3A2.D4.1||
> +MC3A2.D4.10||
>  MC3A2.D4.11||
>  MC3A2.D4.14||
>  MC3A2.R1.1||
> diff --git a/docs/misra/deviations.rst b/docs/misra/deviations.rst
> index fe0b1e10a2..63caa8f4a2 100644
> --- a/docs/misra/deviations.rst
> +++ b/docs/misra/deviations.rst
> @@ -30,6 +30,18 @@ Deviations related to MISRA C:2012 Directives:
>         not to add an additional encapsulation layer.
>       - Tagged as `deliberate` for ECLAIR.
> 
> +   * - D4.10
> +     - Files that are intended to be included more than once (and have
> +       a comment that says this explicitly) do not need to conform to 
> the
> +       directive.
> +     - Tagged as `safe` for ECLAIR.
> +
> +   * - D4.10
> +     - There are autogenerated files that do not need to comply to the
> +       directive.
> +     - Tagged as `safe` for ECLAIR. Such files are:
> +        - xen/include/generated/autoconf.h
> +
>     * - D4.10
>       - Including multiple times a .c file is safe because every 
> function or data item
>         it defines would in (the common case) be already defined.
> diff --git a/xen/arch/x86/include/asm/cpufeatures.h 
> b/xen/arch/x86/include/asm/cpufeatures.h
> index 9e3ed21c02..69041219cb 100644
> --- a/xen/arch/x86/include/asm/cpufeatures.h
> +++ b/xen/arch/x86/include/asm/cpufeatures.h
> @@ -1,6 +1,6 @@
> -/*
> - * Explicitly intended for multiple inclusion.
> - */
> +/* This file is intended to be included multiple times. */
> +/* #ifndef X86_CPUFEATURES_H */
> +/* #define X86_CPUFEATURES_H */
> 

Are these two lines really needed? I may be mistaken, but I think the 
violation's first location would be the #include below with a comment a 
couple of lines above captured by the config at the top [1]. @Federico 
thoughts?

>  #include <xen/lib/x86/cpuid-autogen.h>
> 
> @@ -63,3 +63,5 @@ XEN_CPUFEATURE(USE_VMCALL,        X86_SYNTH(30)) /* 
> Use VMCALL instead of VMMCAL
> 
>  /* Total number of capability words, inc synth and bug words. */
>  #define NCAPINTS (FSCAPINTS + X86_NR_SYNTH + X86_NR_BUG) /* N 32-bit 
> words worth of info */
> +
> +/* #endif X86_CPUFEATURES_H */
> diff --git a/xen/include/xen/compile.h.in 
> b/xen/include/xen/compile.h.in
> index 3151d1e7d1..9206341ba6 100644
> --- a/xen/include/xen/compile.h.in
> +++ b/xen/include/xen/compile.h.in
> @@ -1,3 +1,6 @@
> +#ifndef XEN_COMPILE_H
> +#define XEN_COMPILE_H
> +
>  #define XEN_COMPILE_DATE	"@@date@@"
>  #define XEN_COMPILE_TIME	"@@time@@"
>  #define XEN_COMPILE_BY		"@@whoami@@"
> diff --git a/xen/tools/process-banner.sed 
> b/xen/tools/process-banner.sed
> index 56c76558bc..4cf3f9a116 100755
> --- a/xen/tools/process-banner.sed
> +++ b/xen/tools/process-banner.sed
> @@ -12,3 +12,8 @@ s_(.*)_"\1\\n"_
> 
>  # Trailing \ on all but the final line.
>  $!s_$_ \\_
> +
> +# Append closing header guard
> +$a\
> +\
> +#endif /* XEN_COMPILE_H */

-- 
Nicola Vetrini, B.Sc.
Software Engineer
BUGSENG (https://bugseng.com)
LinkedIn: https://www.linkedin.com/in/nicola-vetrini-a42471253