xen: add deviations for Rule 11.8

The xen sources contain violations of MISRA C:2012 Rule 11.8 whose
headline states:
"A conversion shall not remove any const, volatile or _Atomic qualification
from the type pointed to by a pointer".

The macro 'container_of' violates the Rule because it casts away any
qualifier to do pointer arithmetic, but making the macro definition compliant
would add additional complexity, therefore a deviation is introduced.

Signed-off-by: Maria Celeste Cesario  <maria.celeste.cesario@bugseng.com>
Signed-off-by: Simone Ballarin  <simone.ballarin@bugseng.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

diff --git a/automation/eclair_analysis/ECLAIR/deviations.ecl b/automation/eclair_analysis/ECLAIR/deviations.ecl
index 6806f0eea019cc9109243a1a651c7e5fa7742f2f..4b5140fe3fe4f528490e320575647dfe321a6c7f 100644 (file)
--- a/automation/eclair_analysis/ECLAIR/deviations.ecl
+++ b/automation/eclair_analysis/ECLAIR/deviations.ecl
@@ -303,6 +303,13 @@ constant expressions are required.\""
 # Series 11
 #
 
+-doc_begin="Violations caused by container_of are due to pointer arithmetic operations
+with the provided offset. The resulting pointer is then immediately cast back to its
+original type, which preserves the qualifier. This use is deemed safe.
+Fixing this violation would require to increase code complexity and lower readability."
+-config=MC3R1.R11.8,reports+={safe,"any_area(any_loc(any_exp(macro(^container_of$))))"}
+-doc_end
+
 -doc_begin="This construct is used to check if the type is scalar, and for this purpose the use of 0 as a null pointer constant is deliberate."
 -config=MC3R1.R11.9,reports+={deliberate, "any_area(any_loc(any_exp(macro(^__ACCESS_ONCE$))))"
 }

diff --git a/docs/misra/deviations.rst b/docs/misra/deviations.rst
index 4bd56eb9cc223bd2b8a2eb497f307eb616aa69f8..123c78e20a01ea1a57f0598988a712261e355799 100644 (file)
--- a/docs/misra/deviations.rst
+++ b/docs/misra/deviations.rst
@@ -255,6 +255,13 @@ Deviations related to MISRA C:2012 Rules:
        If no bits are set, 0 is returned.
      - Tagged as `safe` for ECLAIR.
 
+   * - R11.8
+     - Violations caused by container_of are due to pointer arithmetic operations
+       with the provided offset. The resulting pointer is then immediately cast back to its
+       original type, which preserves the qualifier. This use is deemed safe.
+       Fixing this violation would require to increase code complexity and lower readability.
+     - Tagged as `safe` for ECLAIR.
+
    * - R11.9
      - __ACCESS_ONCE uses an integer, which happens to be zero, as a
        compile time check. The typecheck uses a cast. The usage of zero or other