misra: add deviations of MISRA C Rule 5.5

MISRA C Rule 5.5 states: "Identifiers shall be distinct from macro names".

Update ECLAIR configuration to deviate clashes: specify the macros that
should be ignored. Update deviations.rst and rules.rst accordingly.

Signed-off-by: Dmytro Prokopchuk <dmytro_prokopchuk1@epam.com>
Reviewed-by: Nicola Vetrini <nicola.vetrini@bugseng.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>

automation/eclair_analysis/ECLAIR/deviations.ecl

@@ -122,6 +122,16 @@ it defines would (in the common case) be already defined. Peer reviewed by the c
 -config=MC3A2.R5.5,reports+={deliberate, "any_area(decl(kind(function))||any_loc(macro(name(memcpy||memset||memmove))))&&any_area(any_loc(file(^xen/common/libelf/libelf-private\\.h$)))"}
 -doc_end
 
+-doc_begin="Clashes between bitops functions and macro names are deliberate.
+These macros are needed for input validation and error handling."
+-config=MC3A2.R5.5,ignored_macros+="^(__)?(test|set|clear|change|test_and_(set|clear|change))_bit$"
+-doc_end
+
+-doc_begin="Clashes between grant table functions and macro names in 'xen/common/grant_table.c' are deliberate.
+These macros address differences in argument count during compile-time, effectively discarding unused parameters to avoid warnings or errors related to them."
+-config=MC3A2.R5.5,ignored_macros+="name(update_gnttab_par||parse_gnttab_limit)&&loc(file(^xen/common/grant_table\\.c$))"
+-doc_end
+
 -doc_begin="The type \"ret_t\" is deliberately defined multiple times,
 depending on the guest."
 -config=MC3A2.R5.6,reports+={deliberate,"any_area(any_loc(text(^.*ret_t.*$)))"}

docs/misra/deviations.rst

@@ -153,6 +153,28 @@ Deviations related to MISRA C:2012 Rules:
        memmove.
      - Tagged as `deliberate` for ECLAIR.
 
+   * - R5.5
+     - Clashes between bitops ('__test_and_set_bit', '__test_and_clear_bit',
+       '__test_and_change_bit', 'test_bit', 'set_bit', 'clear_bit', 'change_bit',
+       'test_and_set_bit', 'test_and_clear_bit', 'test_and_change_bit')
+       functions and macro names are intentional. These are necessary for error
+       handling and input validation to ensure that the size of the object being
+       referenced by the memory address (passed as an argument to the macro)
+       meets the minimum requirements for the bit operation. This prevents unsafe
+       operations on improperly sized data types that could lead to undefined
+       behavior or memory corruption. The macros encapsulate this conditional
+       logic into a single, reusable form, simplifying the code and avoiding
+       function call overhead. Also this bit operations API was inherited from
+       Linux and should be kept for familiarity.
+     - ECLAIR has been configured to ignore these macros.
+
+   * - R5.5
+     - Clashes between grant table ('update_gnttab_par', 'parse_gnttab_limit')
+       functions and macro names are intentional. These macros address
+       differences in argument count during compile-time, effectively discarding
+       unused 2nd and 3rd parameters to avoid warnings or errors related to them.
+     - ECLAIR has been configured to ignore these macros.
+
    * - R5.6
      - The type ret_t is deliberately defined multiple times depending on the
        type of guest to service.

docs/misra/rules.rst

@@ -205,6 +205,23 @@ maintainers if you want to suggest a change.
            #define f(x, y) f(x, y)
            void f(int x, int y);
 
+       Clashes between bitops functions and macro names are allowed
+       because they are used for input validation and error handling.
+       Example::
+
+           static inline void set_bit(int nr, volatile void *addr)
+           {
+               asm volatile ( "lock btsl %1,%0"
+                              : "+m" (ADDR) : "Ir" (nr) : "memory");
+           }
+           #define set_bit(nr, addr) ({                            \
+               if ( bitop_bad_size(addr) ) __bitop_bad_size();     \
+               set_bit(nr, addr);                                  \
+           })
+
+       Clashes between grant table functions and macro names are allowed
+       because they are used for discarding unused parameters.
+
    * - `Rule 5.6 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_05_06.c>`_
      - Required
      - A typedef name shall be a unique identifier