#ifndef _ASM_X86_ATOMIC_32_H #define _ASM_X86_ATOMIC_32_H #include <linux/compiler.h> #include <linux/types.h> #include <asm/processor.h> #include <asm/cmpxchg.h> /* * Atomic operations that C can't guarantee us. Useful for * resource counting etc.. */ #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 */