automation/eclair: address violations of MISRA C Rule 20.7

MISRA C Rule 20.7 states: "Expressions resulting from the expansion
of macro parameters shall be enclosed in parentheses".

The helper macro bitmap_switch has parameters that cannot be parenthesized
in order to comply with the rule, as that would break its functionality.
Moreover, the risk of misuse due developer confusion is deemed not
substantial enough to warrant a more involved refactor, thus the macro
is deviated for this rule.

No functional change.

Signed-off-by: Nicola Vetrini <nicola.vetrini@bugseng.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Release-Acked-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>

docs/misra/safe.json

@@ -60,6 +60,14 @@
         },
         {
             "id": "SAF-7-safe",
+            "analyser": {
+                "eclair": "MC3R1.R20.7"
+            },
+            "name": "MC3R1.R20.7: deliberately non-parenthesized macro argument",
+            "text": "A macro parameter expands to an expression that is non-parenthesized, as doing so would break the functionality."
+        },
+        {
+            "id": "SAF-8-safe",
             "analyser": {},
             "name": "Sentinel",
             "text": "Next ID to be used"

xen/include/xen/bitmap.h

@@ -103,10 +103,13 @@ extern int bitmap_allocate_region(unsigned long *bitmap, int pos, int order);
 #define bitmap_switch(nbits, zero, small, large)			  \
 	unsigned int n__ = (nbits);					  \
 	if (__builtin_constant_p(nbits) && !n__) {			  \
+		/* SAF-7-safe Rule 20.7 non-parenthesized macro argument */ \
 		zero;							  \
 	} else if (__builtin_constant_p(nbits) && n__ <= BITS_PER_LONG) { \
+		/* SAF-7-safe Rule 20.7 non-parenthesized macro argument */ \
 		small;							  \
 	} else {							  \
+		/* SAF-7-safe Rule 20.7 non-parenthesized macro argument */ \
 		large;							  \
 	}