Commit 212dd847 authored Feb 27, 2026 by Catalin Marinas Committed by Will Deacon Mar 04, 2026

arm64: Silence sparse warnings caused by the type casting in (cmp)xchg



The arm64 xchg/cmpxchg() wrappers cast the arguments to (unsigned long)
prior to invoking the static inline functions implementing the
operation. Some restrictive type annotations (e.g. __bitwise) lead to
sparse warnings like below:

sparse warnings: (new ones prefixed by >>)
   fs/crypto/bio.c:67:17: sparse: sparse: cast from restricted blk_status_t
>> fs/crypto/bio.c:67:17: sparse: sparse: cast to restricted blk_status_t

Force the casting in the arm64 xchg/cmpxchg() wrappers to silence
sparse.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202602230947.uNRsPyBn-lkp@intel.com/
Link: https://lore.kernel.org/r/202602230947.uNRsPyBn-lkp@intel.com/


Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Will Deacon <will@kernel.org>

parent df6e4ab6

arch/arm64/include/asm/cmpxchg.h

+7 −5

Original line number	Diff line number	Diff line
		@@ -91,8 +91,9 @@ __XCHG_GEN(_mb)
		#define __xchg_wrapper(sfx, ptr, x) \
		({ \
		__typeof__(*(ptr)) __ret; \
		__ret = (__typeof__(*(ptr))) \
		__arch_xchg##sfx((unsigned long)(x), (ptr), sizeof(*(ptr))); \
		__ret = (__force __typeof__(*(ptr))) \
		__arch_xchg##sfx((__force unsigned long)(x), (ptr), \
		sizeof(*(ptr))); \
		__ret; \
		})

		@@ -175,9 +176,10 @@ __CMPXCHG_GEN(_mb)
		#define __cmpxchg_wrapper(sfx, ptr, o, n) \
		({ \
		__typeof__(*(ptr)) __ret; \
		__ret = (__typeof__(*(ptr))) \
		__cmpxchg##sfx((ptr), (unsigned long)(o), \
		(unsigned long)(n), sizeof(*(ptr))); \
		__ret = (__force __typeof__(*(ptr))) \
		__cmpxchg##sfx((ptr), (__force unsigned long)(o), \
		(__force unsigned long)(n), \
		sizeof(*(ptr))); \
		__ret; \
		})