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Re: [PATCH 1/4] x86/domain: address Misra rule 11.1 violation in reset_stack_and_call_ind()
- To: Jan Beulich <jbeulich@xxxxxxxx>
- From: Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>
- Date: Sat, 12 Sep 2026 17:09:04 +0200
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- Delivery-date: Sat, 12 Sep 2026 15:09:28 +0000
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On 2026-09-03 13:43, Jan Beulich wrote:
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@xxxxxxxx>
Reviewed-by: Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>
---
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.
The point here is that the types are not identical, if you consider
noreturn as part of the function type (as clang does) or not (as GCC
does). This is the reason why we err on the side of caution and diagnose
this, and it's not likely to change in the near future. Perhaps we could
make the violation message more explicit about the motivation of the
mismatch.
--- 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");
\
})
--
Nicola Vetrini, B.Sc.
Software Engineer
BUGSENG (https://bugseng.com)
LinkedIn: https://www.linkedin.com/in/nicola-vetrini-a42471253
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