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author | Al Viro <viro@zeniv.linux.org.uk> | 2008-08-17 21:05:42 -0400 |
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committer | H. Peter Anvin <hpa@zytor.com> | 2008-10-22 22:55:20 -0700 |
commit | bb8985586b7a906e116db835c64773b7a7d51663 (patch) | |
tree | de93ae58e88cc563d95cc124a73f3930594c6100 /arch/x86/include/asm/atomic_32.h | |
parent | 8ede0bdb63305d3353efd97e9af6210afb05734e (diff) | |
download | blackbird-op-linux-bb8985586b7a906e116db835c64773b7a7d51663.tar.gz blackbird-op-linux-bb8985586b7a906e116db835c64773b7a7d51663.zip |
x86, um: ... and asm-x86 move
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch/x86/include/asm/atomic_32.h')
-rw-r--r-- | arch/x86/include/asm/atomic_32.h | 259 |
1 files changed, 259 insertions, 0 deletions
diff --git a/arch/x86/include/asm/atomic_32.h b/arch/x86/include/asm/atomic_32.h new file mode 100644 index 000000000000..14d3f0beb889 --- /dev/null +++ b/arch/x86/include/asm/atomic_32.h @@ -0,0 +1,259 @@ +#ifndef ASM_X86__ATOMIC_32_H +#define ASM_X86__ATOMIC_32_H + +#include <linux/compiler.h> +#include <asm/processor.h> +#include <asm/cmpxchg.h> + +/* + * Atomic operations that C can't guarantee us. Useful for + * resource counting etc.. + */ + +/* + * Make sure gcc doesn't try to be clever and move things around + * on us. We need to use _exactly_ the address the user gave us, + * not some alias that contains the same information. + */ +typedef struct { + int counter; +} atomic_t; + +#define ATOMIC_INIT(i) { (i) } + +/** + * atomic_read - read atomic variable + * @v: pointer of type atomic_t + * + * Atomically reads the value of @v. + */ +#define atomic_read(v) ((v)->counter) + +/** + * atomic_set - set atomic variable + * @v: pointer of type atomic_t + * @i: required value + * + * Atomically sets the value of @v to @i. + */ +#define atomic_set(v, i) (((v)->counter) = (i)) + +/** + * atomic_add - add integer to atomic variable + * @i: integer value to add + * @v: pointer of type atomic_t + * + * Atomically adds @i to @v. + */ +static inline void atomic_add(int i, atomic_t *v) +{ + asm volatile(LOCK_PREFIX "addl %1,%0" + : "+m" (v->counter) + : "ir" (i)); +} + +/** + * atomic_sub - subtract integer from atomic variable + * @i: integer value to subtract + * @v: pointer of type atomic_t + * + * Atomically subtracts @i from @v. + */ +static inline void atomic_sub(int i, atomic_t *v) +{ + asm volatile(LOCK_PREFIX "subl %1,%0" + : "+m" (v->counter) + : "ir" (i)); +} + +/** + * atomic_sub_and_test - subtract value from variable and test result + * @i: integer value to subtract + * @v: pointer of type atomic_t + * + * Atomically subtracts @i from @v and returns + * true if the result is zero, or false for all + * other cases. + */ +static inline int atomic_sub_and_test(int i, atomic_t *v) +{ + unsigned char c; + + asm volatile(LOCK_PREFIX "subl %2,%0; sete %1" + : "+m" (v->counter), "=qm" (c) + : "ir" (i) : "memory"); + return c; +} + +/** + * atomic_inc - increment atomic variable + * @v: pointer of type atomic_t + * + * Atomically increments @v by 1. + */ +static inline void atomic_inc(atomic_t *v) +{ + asm volatile(LOCK_PREFIX "incl %0" + : "+m" (v->counter)); +} + +/** + * atomic_dec - decrement atomic variable + * @v: pointer of type atomic_t + * + * Atomically decrements @v by 1. + */ +static inline void atomic_dec(atomic_t *v) +{ + asm volatile(LOCK_PREFIX "decl %0" + : "+m" (v->counter)); +} + +/** + * atomic_dec_and_test - decrement and test + * @v: pointer of type atomic_t + * + * Atomically decrements @v by 1 and + * returns true if the result is 0, or false for all other + * cases. + */ +static inline int atomic_dec_and_test(atomic_t *v) +{ + unsigned char c; + + asm volatile(LOCK_PREFIX "decl %0; sete %1" + : "+m" (v->counter), "=qm" (c) + : : "memory"); + return c != 0; +} + +/** + * atomic_inc_and_test - increment and test + * @v: pointer of type atomic_t + * + * Atomically increments @v by 1 + * and returns true if the result is zero, or false for all + * other cases. + */ +static inline int atomic_inc_and_test(atomic_t *v) +{ + unsigned char c; + + asm volatile(LOCK_PREFIX "incl %0; sete %1" + : "+m" (v->counter), "=qm" (c) + : : "memory"); + return c != 0; +} + +/** + * atomic_add_negative - add and test if negative + * @v: pointer of type atomic_t + * @i: integer value to add + * + * Atomically adds @i to @v and returns true + * if the result is negative, or false when + * result is greater than or equal to zero. + */ +static inline int atomic_add_negative(int i, atomic_t *v) +{ + unsigned char c; + + asm volatile(LOCK_PREFIX "addl %2,%0; sets %1" + : "+m" (v->counter), "=qm" (c) + : "ir" (i) : "memory"); + return c; +} + +/** + * atomic_add_return - add integer and return + * @v: pointer of type atomic_t + * @i: integer value to add + * + * Atomically adds @i to @v and returns @i + @v + */ +static inline int atomic_add_return(int i, atomic_t *v) +{ + int __i; +#ifdef CONFIG_M386 + unsigned long flags; + if (unlikely(boot_cpu_data.x86 <= 3)) + goto no_xadd; +#endif + /* Modern 486+ processor */ + __i = i; + asm volatile(LOCK_PREFIX "xaddl %0, %1" + : "+r" (i), "+m" (v->counter) + : : "memory"); + return i + __i; + +#ifdef CONFIG_M386 +no_xadd: /* Legacy 386 processor */ + local_irq_save(flags); + __i = atomic_read(v); + atomic_set(v, i + __i); + local_irq_restore(flags); + return i + __i; +#endif +} + +/** + * atomic_sub_return - subtract integer and return + * @v: pointer of type atomic_t + * @i: integer value to subtract + * + * Atomically subtracts @i from @v and returns @v - @i + */ +static inline int atomic_sub_return(int i, atomic_t *v) +{ + return atomic_add_return(-i, v); +} + +#define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new))) +#define atomic_xchg(v, new) (xchg(&((v)->counter), (new))) + +/** + * atomic_add_unless - add unless the number is already a given value + * @v: pointer of type atomic_t + * @a: the amount to add to v... + * @u: ...unless v is equal to u. + * + * Atomically adds @a to @v, so long as @v was not already @u. + * Returns non-zero if @v was not @u, and zero otherwise. + */ +static inline int atomic_add_unless(atomic_t *v, int a, int u) +{ + int c, old; + c = atomic_read(v); + for (;;) { + if (unlikely(c == (u))) + break; + old = atomic_cmpxchg((v), c, c + (a)); + if (likely(old == c)) + break; + c = old; + } + return c != (u); +} + +#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0) + +#define atomic_inc_return(v) (atomic_add_return(1, v)) +#define atomic_dec_return(v) (atomic_sub_return(1, v)) + +/* These are x86-specific, used by some header files */ +#define atomic_clear_mask(mask, addr) \ + asm volatile(LOCK_PREFIX "andl %0,%1" \ + : : "r" (~(mask)), "m" (*(addr)) : "memory") + +#define atomic_set_mask(mask, addr) \ + asm volatile(LOCK_PREFIX "orl %0,%1" \ + : : "r" (mask), "m" (*(addr)) : "memory") + +/* Atomic operations are already serializing on x86 */ +#define smp_mb__before_atomic_dec() barrier() +#define smp_mb__after_atomic_dec() barrier() +#define smp_mb__before_atomic_inc() barrier() +#define smp_mb__after_atomic_inc() barrier() + +#include <asm-generic/atomic.h> +#endif /* ASM_X86__ATOMIC_32_H */ |