[PATCH 1/4] x86/domain: address Misra rule 11.1 violation in reset_stack_and_call_ind()

[Jan Beulich <jbeulich@suse.com>]

Eclair dislikes both sides of the comparison to differ in noreturn
attributes, thus deeming this a violation of "Conversions shall not be
performed between a pointer to a function and any other type". Since gcc
doesn't permit use of "noreturn" types used in a typecast, resort to
typeof().

No functional change intended.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
---
Really Eclair's diagnosis is misleading here, and not only because of the
missing "noreturn" there, making both sides be identical: There are no
implicit conversions performed on this kind of pointer operands of an
equality expression. A diagnosis of "comparison of pointers to different
types", along the lines of what compilers use, would be more to the point.

--- a/xen/arch/x86/include/asm/current.h
+++ b/xen/arch/x86/include/asm/current.h
@@ -208,7 +208,7 @@ unsigned long get_stack_dump_bottom (uns
 /* The constraint may only specify non-call-clobbered registers. */
 #define reset_stack_and_call_ind(fn)                                    \
     ({                                                                  \
-        (void)((fn) == (void (*)(void))NULL);                           \
+        (void)((fn) == (typeof(dom_xen->arch.ctxt_switch->tail))NULL);  \
         switch_stack_and_jump(fn, "INDIRECT_CALL %", "b");              \
     })