diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/asm-generic/barrier.h | 55 | ||||
| -rw-r--r-- | include/linux/compiler.h | 9 | ||||
| -rw-r--r-- | include/linux/spinlock.h | 10 |
3 files changed, 62 insertions, 12 deletions
diff --git a/include/asm-generic/barrier.h b/include/asm-generic/barrier.h index 639d7a4d033b..6f692f8ac664 100644 --- a/include/asm-generic/barrier.h +++ b/include/asm-generic/barrier.h @@ -1,4 +1,5 @@ -/* Generic barrier definitions, based on MN10300 definitions. +/* + * Generic barrier definitions, originally based on MN10300 definitions. * * It should be possible to use these on really simple architectures, * but it serves more as a starting point for new ports. @@ -16,35 +17,65 @@ #ifndef __ASSEMBLY__ -#define nop() asm volatile ("nop") +#include <linux/compiler.h> + +#ifndef nop +#define nop() asm volatile ("nop") +#endif /* - * Force strict CPU ordering. - * And yes, this is required on UP too when we're talking - * to devices. + * Force strict CPU ordering. And yes, this is required on UP too when we're + * talking to devices. * - * This implementation only contains a compiler barrier. + * Fall back to compiler barriers if nothing better is provided. */ -#define mb() asm volatile ("": : :"memory") +#ifndef mb +#define mb() barrier() +#endif + +#ifndef rmb #define rmb() mb() -#define wmb() asm volatile ("": : :"memory") +#endif + +#ifndef wmb +#define wmb() mb() +#endif + +#ifndef read_barrier_depends +#define read_barrier_depends() do { } while (0) +#endif #ifdef CONFIG_SMP #define smp_mb() mb() #define smp_rmb() rmb() #define smp_wmb() wmb() +#define smp_read_barrier_depends() read_barrier_depends() #else #define smp_mb() barrier() #define smp_rmb() barrier() #define smp_wmb() barrier() +#define smp_read_barrier_depends() do { } while (0) +#endif + +#ifndef set_mb +#define set_mb(var, value) do { (var) = (value); mb(); } while (0) #endif -#define set_mb(var, value) do { var = value; mb(); } while (0) -#define set_wmb(var, value) do { var = value; wmb(); } while (0) +#define smp_store_release(p, v) \ +do { \ + compiletime_assert_atomic_type(*p); \ + smp_mb(); \ + ACCESS_ONCE(*p) = (v); \ +} while (0) -#define read_barrier_depends() do {} while (0) -#define smp_read_barrier_depends() do {} while (0) +#define smp_load_acquire(p) \ +({ \ + typeof(*p) ___p1 = ACCESS_ONCE(*p); \ + compiletime_assert_atomic_type(*p); \ + smp_mb(); \ + ___p1; \ +}) #endif /* !__ASSEMBLY__ */ #endif /* __ASM_GENERIC_BARRIER_H */ diff --git a/include/linux/compiler.h b/include/linux/compiler.h index 92669cd182a6..fe7a686dfd8d 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -298,6 +298,11 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect); # define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b)) #endif +/* Is this type a native word size -- useful for atomic operations */ +#ifndef __native_word +# define __native_word(t) (sizeof(t) == sizeof(int) || sizeof(t) == sizeof(long)) +#endif + /* Compile time object size, -1 for unknown */ #ifndef __compiletime_object_size # define __compiletime_object_size(obj) -1 @@ -337,6 +342,10 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect); #define compiletime_assert(condition, msg) \ _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__) +#define compiletime_assert_atomic_type(t) \ + compiletime_assert(__native_word(t), \ + "Need native word sized stores/loads for atomicity.") + /* * Prevent the compiler from merging or refetching accesses. The compiler * is also forbidden from reordering successive instances of ACCESS_ONCE(), diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h index 75f34949d9ab..3f2867ff0ced 100644 --- a/include/linux/spinlock.h +++ b/include/linux/spinlock.h @@ -130,6 +130,16 @@ do { \ #define smp_mb__before_spinlock() smp_wmb() #endif +/* + * Place this after a lock-acquisition primitive to guarantee that + * an UNLOCK+LOCK pair act as a full barrier. This guarantee applies + * if the UNLOCK and LOCK are executed by the same CPU or if the + * UNLOCK and LOCK operate on the same lock variable. + */ +#ifndef smp_mb__after_unlock_lock +#define smp_mb__after_unlock_lock() do { } while (0) +#endif + /** * raw_spin_unlock_wait - wait until the spinlock gets unlocked * @lock: the spinlock in question. |