From f8b6455a9d381fc513efbec0be0c312b96e6eb6b Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Tue, 25 May 2021 15:02:08 +0100 Subject: [PATCH] locking/atomic: atomic: 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/atomic.h, and it's impractical to convert the header 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 atomic_*() or arch_atomic_*() depending on whether ARCH_ATOMIC is selected. To do this, the C implementations are prefixed as generic_atomic_*(), and preprocessor definitions map atomic_*()/arch_atomic_*() 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 Cc: Arnd Bergmann Cc: Boqun Feng Cc: Peter Zijlstra Cc: Will Deacon Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20210525140232.53872-10-mark.rutland@arm.com --- include/asm-generic/atomic.h | 71 +++++++++++++++++++++++++++++++----- 1 file changed, 62 insertions(+), 9 deletions(-) diff --git a/include/asm-generic/atomic.h b/include/asm-generic/atomic.h index 316c82a27b0a..649060fa0fe8 100644 --- a/include/asm-generic/atomic.h +++ b/include/asm-generic/atomic.h @@ -12,39 +12,47 @@ #include #include +#ifdef CONFIG_ARCH_ATOMIC +#define __ga_cmpxchg arch_cmpxchg +#define __ga_xchg arch_xchg +#else +#define __ga_cmpxchg cmpxchg +#define __ga_xchg xchg +#endif + #ifdef CONFIG_SMP /* we can build all atomic primitives from cmpxchg */ #define ATOMIC_OP(op, c_op) \ -static inline void atomic_##op(int i, atomic_t *v) \ +static inline void generic_atomic_##op(int i, atomic_t *v) \ { \ int c, old; \ \ c = v->counter; \ - while ((old = cmpxchg(&v->counter, c, c c_op i)) != c) \ + while ((old = __ga_cmpxchg(&v->counter, c, c c_op i)) != c) \ c = old; \ } #define ATOMIC_OP_RETURN(op, c_op) \ -static inline int atomic_##op##_return(int i, atomic_t *v) \ +static inline int generic_atomic_##op##_return(int i, atomic_t *v) \ { \ int c, old; \ \ c = v->counter; \ - while ((old = cmpxchg(&v->counter, c, c c_op i)) != c) \ + while ((old = __ga_cmpxchg(&v->counter, c, c c_op i)) != c) \ c = old; \ \ return c c_op i; \ } #define ATOMIC_FETCH_OP(op, c_op) \ -static inline int atomic_fetch_##op(int i, atomic_t *v) \ +static inline int generic_atomic_fetch_##op(int i, atomic_t *v) \ { \ int c, old; \ \ c = v->counter; \ - while ((old = cmpxchg(&v->counter, c, c c_op i)) != c) \ + while ((old = __ga_cmpxchg(&v->counter, c, c c_op i)) != c) \ c = old; \ \ return c; \ @@ -55,7 +63,7 @@ static inline int atomic_fetch_##op(int i, atomic_t *v) \ #include #define ATOMIC_OP(op, c_op) \ -static inline void atomic_##op(int i, atomic_t *v) \ +static inline void generic_atomic_##op(int i, atomic_t *v) \ { \ unsigned long flags; \ \ @@ -65,7 +73,7 @@ static inline void atomic_##op(int i, atomic_t *v) \ } #define ATOMIC_OP_RETURN(op, c_op) \ -static inline int atomic_##op##_return(int i, atomic_t *v) \ +static inline int generic_atomic_##op##_return(int i, atomic_t *v) \ { \ unsigned long flags; \ int ret; \ @@ -78,7 +86,7 @@ static inline int atomic_##op##_return(int i, atomic_t *v) \ } #define ATOMIC_FETCH_OP(op, c_op) \ -static inline int atomic_fetch_##op(int i, atomic_t *v) \ +static inline int generic_atomic_fetch_##op(int i, atomic_t *v) \ { \ unsigned long flags; \ int ret; \ @@ -112,10 +120,55 @@ ATOMIC_OP(xor, ^) #undef ATOMIC_OP_RETURN #undef ATOMIC_OP +#undef __ga_cmpxchg +#undef __ga_xchg + +#ifdef CONFIG_ARCH_ATOMIC + +#define arch_atomic_add_return generic_atomic_add_return +#define arch_atomic_sub_return generic_atomic_sub_return + +#define arch_atomic_fetch_add generic_atomic_fetch_add +#define arch_atomic_fetch_sub generic_atomic_fetch_sub +#define arch_atomic_fetch_and generic_atomic_fetch_and +#define arch_atomic_fetch_or generic_atomic_fetch_or +#define arch_atomic_fetch_xor generic_atomic_fetch_xor + +#define arch_atomic_add generic_atomic_add +#define arch_atomic_sub generic_atomic_sub +#define arch_atomic_and generic_atomic_and +#define arch_atomic_or generic_atomic_or +#define arch_atomic_xor generic_atomic_xor + +#define arch_atomic_read(v) READ_ONCE((v)->counter) +#define arch_atomic_set(v, i) WRITE_ONCE(((v)->counter), (i)) + +#define arch_atomic_xchg(ptr, v) (arch_xchg(&(ptr)->counter, (v))) +#define arch_atomic_cmpxchg(v, old, new) (arch_cmpxchg(&((v)->counter), (old), (new))) + +#else /* CONFIG_ARCH_ATOMIC */ + +#define atomic_add_return generic_atomic_add_return +#define atomic_sub_return generic_atomic_sub_return + +#define atomic_fetch_add generic_atomic_fetch_add +#define atomic_fetch_sub generic_atomic_fetch_sub +#define atomic_fetch_and generic_atomic_fetch_and +#define atomic_fetch_or generic_atomic_fetch_or +#define atomic_fetch_xor generic_atomic_fetch_xor + +#define atomic_add generic_atomic_add +#define atomic_sub generic_atomic_sub +#define atomic_and generic_atomic_and +#define atomic_or generic_atomic_or +#define atomic_xor generic_atomic_xor + #define atomic_read(v) READ_ONCE((v)->counter) #define atomic_set(v, i) WRITE_ONCE(((v)->counter), (i)) #define atomic_xchg(ptr, v) (xchg(&(ptr)->counter, (v))) #define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new))) +#endif /* CONFIG_ARCH_ATOMIC */ + #endif /* __ASM_GENERIC_ATOMIC_H */