[xen master] docs/misra: add rule 2.1 exceptions

[patchbot@xxxxxxx]

commit 5bdfcf7fe89759321335159c8304833dc32a25cd
Author:     Stefano Stabellini <stefano.stabellini@xxxxxxx>
AuthorDate: Wed Aug 23 15:39:42 2023 -0700
Commit:     Stefano Stabellini <stefano.stabellini@xxxxxxx>
CommitDate: Fri Sep 29 11:00:47 2023 -0700

    docs/misra: add rule 2.1 exceptions
    
    During the discussions that led to the acceptance of Rule 2.1, we
    decided on a few exceptions that were not properly recorded in
    rules.rst. Add them now.
    
    Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxx>
    Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by: Bertrand Marquis <bertrand.marquis@xxxxxxx>
    Release-acked-by: Henry Wang <Henry.Wang@xxxxxxx>
---
 docs/misra/rules.rst | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/docs/misra/rules.rst b/docs/misra/rules.rst
index 661aa95e23..a2fe01464e 100644
--- a/docs/misra/rules.rst
+++ b/docs/misra/rules.rst
@@ -107,7 +107,16 @@ maintainers if you want to suggest a change.
    * - `Rule 2.1 
<https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_02_01_1.c>`_
      - Required
      - A project shall not contain unreachable code
-     -
+     - The following are allowed:
+         - Invariantly constant conditions, e.g. if(IS_ENABLED(CONFIG_HVM)) { 
S; }
+         - Switch with a controlling value statically determined not to
+           match one or more case statements
+         - Functions that are intended to be referenced only from
+           assembly code (e.g. 'do_trap_fiq')
+         - asm-offsets.c, as they are not linked deliberately, because
+           they are used to generate definitions for asm modules
+         - Declarations without initializer are safe, as they are not
+           executed
 
    * - `Rule 2.6 
<https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_02_06.c>`_
      - Advisory
--
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