Re: Address MISRA C:2012 Rule 8.4

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

I think that's OK for me. My only concern is that we should track the
project-wide deviations properly somewhere besides the ECLAIR
configuration under xen.git which is ECLAIR specific. So far we used the
notes in docs/misra/rules.rst. I don't know if that sufficient, but we
could add a note for 8.4:

diff --git a/docs/misra/rules.rst b/docs/misra/rules.rst
index 8f0e4d3f25..5977bc9d5e 100644
--- a/docs/misra/rules.rst
+++ b/docs/misra/rules.rst
@@ -245,7 +245,8 @@ maintainers if you want to suggest a change.
      - Required
      - A compatible declaration shall be visible when an object or
        function with external linkage is defined
-     -
+     - No need for declarations when functions are only called from
+       assembly
 
    * - `Rule 8.5 
<https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_08_05_2.c>`_
      - Required


On Thu, 3 Aug 2023, Nicola Vetrini wrote:
> The headline of Rule 8.4 is as follows:
> "A compatible declaration shall be visible when an object or
> function with external linkage is defined".
> 
> Some functions reported in [1][2] are lacking a declaration in the respective
> header files;
> as remarked on xen-devel's IRC channel, this is ok since they are only called
> from asm code (e.g., start_xen). A similar discussion
> had taken place in the past (see [3]) and the general consensus was to deviate
> these cases.
> If that is still the case, a suitable project-wide deviation can be added to
> address these violations.
> 
> [1]
> https://saas.eclairit.com:3787/fs/var/local/eclair/XEN.ecdf/ECLAIR_normal/origin/staging/ARM64-Set1/210/PROJECT.ecd;/by_service/MC3R1.R8.4.html
> [2]
> https://saas.eclairit.com:3787/fs/var/local/eclair/XEN.ecdf/ECLAIR_normal/origin/staging/X86_64-Set1/210/PROJECT.ecd;/by_service/MC3R1.R8.4.html
> [3] https://lore.kernel.org/all/20220705210218.483854-2-burzalodowa@xxxxxxxxx/
> 
> Regards,
> 
> -- 
> Nicola Vetrini, BSc
> Software Engineer, BUGSENG srl (https://bugseng.com)
>