locking/atomic: arm: move to ARCH_ATOMIC

We'd like all architectures to convert to ARCH_ATOMIC, as once all
architectures are converted it will be possible to make significant
cleanups to the atomics headers, and this will make it much easier to
generically enable atomic functionality (e.g. debug logic in the
instrumented wrappers).

As a step towards that, this patch migrates alpha to ARCH_ATOMIC. The
arch code provides arch_{atomic,atomic64,xchg,cmpxchg}*(), and common
code wraps these with optional instrumentation to provide the regular
functions.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210525140232.53872-16-mark.rutland@arm.com

arch/arm/Kconfig

@@ -3,6 +3,7 @@ config ARM
 	bool
 	default y
 	select ARCH_32BIT_OFF_T
+	select ARCH_ATOMIC
 	select ARCH_HAS_BINFMT_FLAT
 	select ARCH_HAS_DEBUG_VIRTUAL if MMU
 	select ARCH_HAS_DMA_WRITE_COMBINE if !ARM_DMA_MEM_BUFFERABLE

arch/arm/include/asm/cmpxchg.h

@@ -114,7 +114,7 @@ static inline unsigned long __xchg(unsigned long x, volatile void *ptr, int size
 	return ret;
 }
 
-#define xchg_relaxed(ptr, x) ({						\
+#define arch_xchg_relaxed(ptr, x) ({					\
 	(__typeof__(*(ptr)))__xchg((unsigned long)(x), (ptr),		\
 				   sizeof(*(ptr)));			\
 })
@@ -128,20 +128,20 @@ static inline unsigned long __xchg(unsigned long x, volatile void *ptr, int size
 #error "SMP is not supported on this platform"
 #endif
 
-#define xchg xchg_relaxed
+#define arch_xchg arch_xchg_relaxed
 
 /*
  * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
  * them available.
  */
-#define cmpxchg_local(ptr, o, n) ({					\
+#define arch_cmpxchg_local(ptr, o, n) ({				\
 	(__typeof(*ptr))__generic_cmpxchg_local((ptr),			\
 					        (unsigned long)(o),	\
 					        (unsigned long)(n),	\
 					        sizeof(*(ptr)));	\
 })
 
-#define cmpxchg64_local(ptr, o, n) __generic_cmpxchg64_local((ptr), (o), (n))
+#define arch_cmpxchg64_local(ptr, o, n) __generic_cmpxchg64_local((ptr), (o), (n))
 
 #include <asm-generic/cmpxchg.h>
 
@@ -207,7 +207,7 @@ static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
 	return oldval;
 }
 
-#define cmpxchg_relaxed(ptr,o,n) ({					\
+#define arch_cmpxchg_relaxed(ptr,o,n) ({				\
 	(__typeof__(*(ptr)))__cmpxchg((ptr),				\
 				      (unsigned long)(o),		\
 				      (unsigned long)(n),		\
@@ -234,7 +234,7 @@ static inline unsigned long __cmpxchg_local(volatile void *ptr,
 	return ret;
 }
 
-#define cmpxchg_local(ptr, o, n) ({					\
+#define arch_cmpxchg_local(ptr, o, n) ({				\
 	(__typeof(*ptr))__cmpxchg_local((ptr),				\
 				        (unsigned long)(o),		\
 				        (unsigned long)(n),		\
@@ -266,13 +266,13 @@ static inline unsigned long long __cmpxchg64(unsigned long long *ptr,
 	return oldval;
 }
 
-#define cmpxchg64_relaxed(ptr, o, n) ({					\
+#define arch_cmpxchg64_relaxed(ptr, o, n) ({				\
 	(__typeof__(*(ptr)))__cmpxchg64((ptr),				\
 					(unsigned long long)(o),	\
 					(unsigned long long)(n));	\
 })
 
-#define cmpxchg64_local(ptr, o, n) cmpxchg64_relaxed((ptr), (o), (n))
+#define arch_cmpxchg64_local(ptr, o, n) arch_cmpxchg64_relaxed((ptr), (o), (n))
 
 #endif	/* __LINUX_ARM_ARCH__ >= 6 */
 

arch/arm/include/asm/sync_bitops.h

@@ -21,7 +21,7 @@
 #define sync_test_and_clear_bit(nr, p)	_test_and_clear_bit(nr, p)
 #define sync_test_and_change_bit(nr, p)	_test_and_change_bit(nr, p)
 #define sync_test_bit(nr, addr)		test_bit(nr, addr)
-#define sync_cmpxchg			cmpxchg
+#define arch_sync_cmpxchg		arch_cmpxchg
 
 
 #endif