The following commit has been merged into the locking/core branch of tip: Commit-ID: 82b993e8249ae3cb29c1b6eb8f6548f5748508b7 Gitweb: https://git.kernel.org/tip/82b993e8249ae3cb29c1b6eb8f6548f5748508b7 Author: Mark Rutland <mark.rutland@xxxxxxx> AuthorDate: Tue, 25 May 2021 15:02:11 +01:00 Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx> CommitterDate: Wed, 26 May 2021 13:20:50 +02:00 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@xxxxxxx> Cc: Arnd Bergmann <arnd@xxxxxxxx> Cc: Boqun Feng <boqun.feng@xxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Will Deacon <will@xxxxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20210525140232.53872-13-mark.rutland@xxxxxxx --- include/asm-generic/cmpxchg.h | 61 ++++++++++++++++++++++++---------- 1 file changed, 44 insertions(+), 17 deletions(-) diff --git a/include/asm-generic/cmpxchg.h b/include/asm-generic/cmpxchg.h index b9d54c7..98c9311 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 */
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