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authorMark Rutland <mark.rutland@arm.com>2021-05-25 15:02:11 +0100
committerPeter Zijlstra <peterz@infradead.org>2021-05-26 13:20:50 +0200
commit82b993e8249ae3cb29c1b6eb8f6548f5748508b7 (patch)
tree796e34d53dabf31ea804b748466cf81a7edd1e9f /include/asm-generic
parent6988631bdfddcedc1d27f83723ea36a442f00ea1 (diff)
locking/atomic: cmpxchg: support ARCH_ATOMIC
We'd like all architectures to convert to ARCH_ATOMIC, as this will enable functionality, and once all architectures are converted it will be possible to make significant cleanups to the atomic headers. A number of architectures use asm-generic/cmpxchg.h or asm-generic/cmpxhg-local.h, and it's impractical to convert the headers and all these architectures in one go. To make it possible to convert them one-by-one, let's make the asm-generic implementation function as either cmpxchg*() or arch_cmpxchg*() depending on whether ARCH_ATOMIC is selected. To do this, the generic implementations are prefixed as generic_cmpxchg_*(), and preprocessor definitions map cmpxchg_*()/arch_cmpxchg_*() onto these as appropriate. Once all users are moved over to ARCH_ATOMIC the ifdeffery in the header can be simplified and/or removed entirely. For existing users (none of which select ARCH_ATOMIC), there should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20210525140232.53872-13-mark.rutland@arm.com
Diffstat (limited to 'include/asm-generic')
-rw-r--r--include/asm-generic/cmpxchg.h61
1 files changed, 44 insertions, 17 deletions
diff --git a/include/asm-generic/cmpxchg.h b/include/asm-generic/cmpxchg.h
index b9d54c7afc52..98c931199089 100644
--- a/include/asm-generic/cmpxchg.h
+++ b/include/asm-generic/cmpxchg.h
@@ -14,16 +14,14 @@
#include <linux/types.h>
#include <linux/irqflags.h>
-#ifndef xchg
-
/*
* This function doesn't exist, so you'll get a linker error if
* something tries to do an invalidly-sized xchg().
*/
-extern void __xchg_called_with_bad_pointer(void);
+extern void __generic_xchg_called_with_bad_pointer(void);
static inline
-unsigned long __xchg(unsigned long x, volatile void *ptr, int size)
+unsigned long __generic_xchg(unsigned long x, volatile void *ptr, int size)
{
unsigned long ret, flags;
@@ -75,35 +73,64 @@ unsigned long __xchg(unsigned long x, volatile void *ptr, int size)
#endif /* CONFIG_64BIT */
default:
- __xchg_called_with_bad_pointer();
+ __generic_xchg_called_with_bad_pointer();
return x;
}
}
-#define xchg(ptr, x) ({ \
- ((__typeof__(*(ptr))) \
- __xchg((unsigned long)(x), (ptr), sizeof(*(ptr)))); \
+#define generic_xchg(ptr, x) ({ \
+ ((__typeof__(*(ptr))) \
+ __generic_xchg((unsigned long)(x), (ptr), sizeof(*(ptr)))); \
})
-#endif /* xchg */
-
/*
* Atomic compare and exchange.
*/
#include <asm-generic/cmpxchg-local.h>
-#ifndef cmpxchg_local
-#define cmpxchg_local(ptr, o, n) ({ \
- ((__typeof__(*(ptr)))__generic_cmpxchg_local((ptr), (unsigned long)(o),\
- (unsigned long)(n), sizeof(*(ptr)))); \
+#define generic_cmpxchg_local(ptr, o, n) ({ \
+ ((__typeof__(*(ptr)))__generic_cmpxchg_local((ptr), (unsigned long)(o), \
+ (unsigned long)(n), sizeof(*(ptr)))); \
})
+
+#define generic_cmpxchg64_local(ptr, o, n) \
+ __generic_cmpxchg64_local((ptr), (o), (n))
+
+
+#ifdef CONFIG_ARCH_ATOMIC
+
+#ifndef arch_xchg
+#define arch_xchg generic_xchg
+#endif
+
+#ifndef arch_cmpxchg_local
+#define arch_cmpxchg_local generic_cmpxchg_local
+#endif
+
+#ifndef arch_cmpxchg64_local
+#define arch_cmpxchg64_local generic_cmpxchg64_local
+#endif
+
+#define arch_cmpxchg arch_cmpxchg_local
+#define arch_cmpxchg64 arch_cmpxchg64_local
+
+#else /* CONFIG_ARCH_ATOMIC */
+
+#ifndef xchg
+#define xchg generic_xchg
+#endif
+
+#ifndef cmpxchg_local
+#define cmpxchg_local generic_cmpxchg_local
#endif
#ifndef cmpxchg64_local
-#define cmpxchg64_local(ptr, o, n) __generic_cmpxchg64_local((ptr), (o), (n))
+#define cmpxchg64_local generic_cmpxchg64_local
#endif
-#define cmpxchg(ptr, o, n) cmpxchg_local((ptr), (o), (n))
-#define cmpxchg64(ptr, o, n) cmpxchg64_local((ptr), (o), (n))
+#define cmpxchg cmpxchg_local
+#define cmpxchg64 cmpxchg64_local
+
+#endif /* CONFIG_ARCH_ATOMIC */
#endif /* __ASM_GENERIC_CMPXCHG_H */