#ifndef _ASM_X86_ATOMIC_H #define _ASM_X86_ATOMIC_H #include #include #include #include #include /* * 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. */ static inline int atomic_read(const atomic_t *v) { return (*(volatile const int *)&(v)->counter); } /** * atomic_read_unchecked - read atomic variable * @v: pointer of type atomic_unchecked_t * * Atomically reads the value of @v. */ static inline int __intentional_overflow(-1) atomic_read_unchecked(const atomic_unchecked_t *v) { return (*(volatile const int *)&(v)->counter); } /** * atomic_set - set atomic variable * @v: pointer of type atomic_t * @i: required value * * Atomically sets the value of @v to @i. */ static inline void atomic_set(atomic_t *v, int i) { v->counter = i; } /** * atomic_set_unchecked - set atomic variable * @v: pointer of type atomic_unchecked_t * @i: required value * * Atomically sets the value of @v to @i. */ static inline void atomic_set_unchecked(atomic_unchecked_t *v, int 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\n" #ifdef CONFIG_PAX_REFCOUNT "jno 0f\n" LOCK_PREFIX "subl %1,%0\n" "int $4\n0:\n" _ASM_EXTABLE(0b, 0b) #endif : "+m" (v->counter) : "ir" (i)); } /** * atomic_add_unchecked - add integer to atomic variable * @i: integer value to add * @v: pointer of type atomic_unchecked_t * * Atomically adds @i to @v. */ static inline void atomic_add_unchecked(int i, atomic_unchecked_t *v) { asm volatile(LOCK_PREFIX "addl %1,%0\n" : "+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\n" #ifdef CONFIG_PAX_REFCOUNT "jno 0f\n" LOCK_PREFIX "addl %1,%0\n" "int $4\n0:\n" _ASM_EXTABLE(0b, 0b) #endif : "+m" (v->counter) : "ir" (i)); } /** * atomic_sub_unchecked - subtract integer from atomic variable * @i: integer value to subtract * @v: pointer of type atomic_unchecked_t * * Atomically subtracts @i from @v. */ static inline void atomic_sub_unchecked(int i, atomic_unchecked_t *v) { asm volatile(LOCK_PREFIX "subl %1,%0\n" : "+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\n" #ifdef CONFIG_PAX_REFCOUNT "jno 0f\n" LOCK_PREFIX "addl %2,%0\n" "int $4\n0:\n" _ASM_EXTABLE(0b, 0b) #endif "sete %1\n" : "+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\n" #ifdef CONFIG_PAX_REFCOUNT "jno 0f\n" LOCK_PREFIX "decl %0\n" "int $4\n0:\n" _ASM_EXTABLE(0b, 0b) #endif : "+m" (v->counter)); } /** * atomic_inc_unchecked - increment atomic variable * @v: pointer of type atomic_unchecked_t * * Atomically increments @v by 1. */ static inline void atomic_inc_unchecked(atomic_unchecked_t *v) { asm volatile(LOCK_PREFIX "incl %0\n" : "+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\n" #ifdef CONFIG_PAX_REFCOUNT "jno 0f\n" LOCK_PREFIX "incl %0\n" "int $4\n0:\n" _ASM_EXTABLE(0b, 0b) #endif : "+m" (v->counter)); } /** * atomic_dec_unchecked - decrement atomic variable * @v: pointer of type atomic_unchecked_t * * Atomically decrements @v by 1. */ static inline void atomic_dec_unchecked(atomic_unchecked_t *v) { asm volatile(LOCK_PREFIX "decl %0\n" : "+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\n" #ifdef CONFIG_PAX_REFCOUNT "jno 0f\n" LOCK_PREFIX "incl %0\n" "int $4\n0:\n" _ASM_EXTABLE(0b, 0b) #endif "sete %1\n" : "+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\n" #ifdef CONFIG_PAX_REFCOUNT "jno 0f\n" LOCK_PREFIX "decl %0\n" "int $4\n0:\n" _ASM_EXTABLE(0b, 0b) #endif "sete %1\n" : "+m" (v->counter), "=qm" (c) : : "memory"); return c != 0; } /** * atomic_inc_and_test_unchecked - increment and test * @v: pointer of type atomic_unchecked_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_unchecked(atomic_unchecked_t *v) { unsigned char c; asm volatile(LOCK_PREFIX "incl %0\n" "sete %1\n" : "+m" (v->counter), "=qm" (c) : : "memory"); return c != 0; } /** * atomic_add_negative - add and test if negative * @i: integer value to add * @v: pointer of type atomic_t * * 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\n" #ifdef CONFIG_PAX_REFCOUNT "jno 0f\n" LOCK_PREFIX "subl %2,%0\n" "int $4\n0:\n" _ASM_EXTABLE(0b, 0b) #endif "sets %1\n" : "+m" (v->counter), "=qm" (c) : "ir" (i) : "memory"); return c; } /** * atomic_add_return - add integer and return * @i: integer value to add * @v: pointer of type atomic_t * * Atomically adds @i to @v and returns @i + @v */ static inline int atomic_add_return(int i, atomic_t *v) { #ifdef CONFIG_M386 int __i; unsigned long flags; if (unlikely(boot_cpu_data.x86 <= 3)) goto no_xadd; #endif /* Modern 486+ processor */ return i + xadd_check_overflow(&v->counter, i); #ifdef CONFIG_M386 no_xadd: /* Legacy 386 processor */ raw_local_irq_save(flags); __i = atomic_read(v); atomic_set(v, i + __i); raw_local_irq_restore(flags); return i + __i; #endif } /** * atomic_add_return_unchecked - add integer and return * @i: integer value to add * @v: pointer of type atomic_unchecked_t * * Atomically adds @i to @v and returns @i + @v */ static inline int atomic_add_return_unchecked(int i, atomic_unchecked_t *v) { #ifdef CONFIG_M386 int __i; unsigned long flags; if (unlikely(boot_cpu_data.x86 <= 3)) goto no_xadd; #endif /* Modern 486+ processor */ return i + xadd(&v->counter, i); #ifdef CONFIG_M386 no_xadd: /* Legacy 386 processor */ raw_local_irq_save(flags); __i = atomic_read_unchecked(v); atomic_set_unchecked(v, i + __i); raw_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_inc_return(v) (atomic_add_return(1, v)) static inline int atomic_inc_return_unchecked(atomic_unchecked_t *v) { return atomic_add_return_unchecked(1, v); } #define atomic_dec_return(v) (atomic_sub_return(1, v)) static inline int __intentional_overflow(-1) atomic_cmpxchg(atomic_t *v, int old, int new) { return cmpxchg(&v->counter, old, new); } static inline int atomic_cmpxchg_unchecked(atomic_unchecked_t *v, int old, int new) { return cmpxchg(&v->counter, old, new); } static inline int atomic_xchg(atomic_t *v, int new) { return xchg(&v->counter, new); } static inline int atomic_xchg_unchecked(atomic_unchecked_t *v, int new) { return 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 the old value of @v. */ static inline int __atomic_add_unless(atomic_t *v, int a, int u) { int c, old, new; c = atomic_read(v); for (;;) { if (unlikely(c == u)) break; asm volatile("addl %2,%0\n" #ifdef CONFIG_PAX_REFCOUNT "jno 0f\n" "subl %2,%0\n" "int $4\n0:\n" _ASM_EXTABLE(0b, 0b) #endif : "=r" (new) : "0" (c), "ir" (a)); old = atomic_cmpxchg(v, c, new); if (likely(old == c)) break; c = old; } return c; } /** * atomic_inc_not_zero_hint - increment if not null * @v: pointer of type atomic_t * @hint: probable value of the atomic before the increment * * This version of atomic_inc_not_zero() gives a hint of probable * value of the atomic. This helps processor to not read the memory * before doing the atomic read/modify/write cycle, lowering * number of bus transactions on some arches. * * Returns: 0 if increment was not done, 1 otherwise. */ #define atomic_inc_not_zero_hint atomic_inc_not_zero_hint static inline int atomic_inc_not_zero_hint(atomic_t *v, int hint) { int val, c = hint, new; /* sanity test, should be removed by compiler if hint is a constant */ if (!hint) return __atomic_add_unless(v, 1, 0); do { asm volatile("incl %0\n" #ifdef CONFIG_PAX_REFCOUNT "jno 0f\n" "decl %0\n" "int $4\n0:\n" _ASM_EXTABLE(0b, 0b) #endif : "=r" (new) : "0" (c)); val = atomic_cmpxchg(v, c, new); if (val == c) return 1; c = val; } while (c); return 0; } /* * atomic_dec_if_positive - decrement by 1 if old value positive * @v: pointer of type atomic_t * * The function returns the old value of *v minus 1, even if * the atomic variable, v, was not decremented. */ static inline int atomic_dec_if_positive(atomic_t *v) { int c, old, dec; c = atomic_read(v); for (;;) { dec = c - 1; if (unlikely(dec < 0)) break; old = atomic_cmpxchg((v), c, dec); if (likely(old == c)) break; c = old; } return dec; } /** * atomic_inc_short - increment of a short integer * @v: pointer to type int * * Atomically adds 1 to @v * Returns the new value of @u */ static inline short int atomic_inc_short(short int *v) { asm(LOCK_PREFIX "addw $1, %0" : "+m" (*v)); return *v; } #ifdef CONFIG_X86_64 /** * atomic_or_long - OR of two long integers * @v1: pointer to type unsigned long * @v2: pointer to type unsigned long * * Atomically ORs @v1 and @v2 * Returns the result of the OR */ static inline void atomic_or_long(unsigned long *v1, unsigned long v2) { asm(LOCK_PREFIX "orq %1, %0" : "+m" (*v1) : "r" (v2)); } #endif /* These are x86-specific, used by some header files */ static inline void atomic_clear_mask(unsigned int mask, atomic_t *v) { asm volatile(LOCK_PREFIX "andl %1,%0" : "+m" (v->counter) : "r" (~(mask)) : "memory"); } static inline void atomic_clear_mask_unchecked(unsigned int mask, atomic_unchecked_t *v) { asm volatile(LOCK_PREFIX "andl %1,%0" : "+m" (v->counter) : "r" (~(mask)) : "memory"); } static inline void atomic_set_mask(unsigned int mask, atomic_t *v) { asm volatile(LOCK_PREFIX "orl %1,%0" : "+m" (v->counter) : "r" (mask) : "memory"); } static inline void atomic_set_mask_unchecked(unsigned int mask, atomic_unchecked_t *v) { asm volatile(LOCK_PREFIX "orl %1,%0" : "+m" (v->counter) : "r" (mask) : "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() #ifdef CONFIG_X86_32 # include "atomic64_32.h" #else # include "atomic64_64.h" #endif #endif /* _ASM_X86_ATOMIC_H */