442 lines
10 KiB
C
442 lines
10 KiB
C
#ifndef _ASM_X86_ATOMIC_32_H
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#define _ASM_X86_ATOMIC_32_H
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#include <linux/compiler.h>
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#include <linux/types.h>
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#include <asm/processor.h>
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#include <asm/cmpxchg.h>
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/*
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* Atomic operations that C can't guarantee us. Useful for
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* resource counting etc..
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*/
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#define ATOMIC_INIT(i) { (i) }
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/**
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* atomic_read - read atomic variable
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* @v: pointer of type atomic_t
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*
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* Atomically reads the value of @v.
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*/
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static inline int atomic_read(const atomic_t *v)
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{
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return v->counter;
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}
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/**
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* atomic_set - set atomic variable
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* @v: pointer of type atomic_t
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* @i: required value
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*
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* Atomically sets the value of @v to @i.
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*/
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static inline void atomic_set(atomic_t *v, int i)
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{
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v->counter = i;
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}
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/**
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* atomic_add - add integer to atomic variable
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* @i: integer value to add
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* @v: pointer of type atomic_t
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*
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* Atomically adds @i to @v.
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*/
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static inline void atomic_add(int i, atomic_t *v)
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{
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asm volatile(LOCK_PREFIX "addl %1,%0"
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: "+m" (v->counter)
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: "ir" (i));
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}
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/**
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* atomic_sub - subtract integer from atomic variable
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* @i: integer value to subtract
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* @v: pointer of type atomic_t
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*
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* Atomically subtracts @i from @v.
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*/
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static inline void atomic_sub(int i, atomic_t *v)
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{
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asm volatile(LOCK_PREFIX "subl %1,%0"
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: "+m" (v->counter)
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: "ir" (i));
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}
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/**
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* atomic_sub_and_test - subtract value from variable and test result
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* @i: integer value to subtract
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* @v: pointer of type atomic_t
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*
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* Atomically subtracts @i from @v and returns
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* true if the result is zero, or false for all
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* other cases.
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*/
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static inline int atomic_sub_and_test(int i, atomic_t *v)
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{
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unsigned char c;
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asm volatile(LOCK_PREFIX "subl %2,%0; sete %1"
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: "+m" (v->counter), "=qm" (c)
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: "ir" (i) : "memory");
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return c;
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}
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/**
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* atomic_inc - increment atomic variable
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* @v: pointer of type atomic_t
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*
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* Atomically increments @v by 1.
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*/
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static inline void atomic_inc(atomic_t *v)
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{
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asm volatile(LOCK_PREFIX "incl %0"
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: "+m" (v->counter));
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}
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/**
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* atomic_dec - decrement atomic variable
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* @v: pointer of type atomic_t
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*
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* Atomically decrements @v by 1.
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*/
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static inline void atomic_dec(atomic_t *v)
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{
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asm volatile(LOCK_PREFIX "decl %0"
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: "+m" (v->counter));
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}
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/**
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* atomic_dec_and_test - decrement and test
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* @v: pointer of type atomic_t
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*
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* Atomically decrements @v by 1 and
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* returns true if the result is 0, or false for all other
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* cases.
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*/
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static inline int atomic_dec_and_test(atomic_t *v)
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{
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unsigned char c;
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asm volatile(LOCK_PREFIX "decl %0; sete %1"
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: "+m" (v->counter), "=qm" (c)
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: : "memory");
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return c != 0;
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}
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/**
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* atomic_inc_and_test - increment and test
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* @v: pointer of type atomic_t
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*
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* Atomically increments @v by 1
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* and returns true if the result is zero, or false for all
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* other cases.
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*/
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static inline int atomic_inc_and_test(atomic_t *v)
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{
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unsigned char c;
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asm volatile(LOCK_PREFIX "incl %0; sete %1"
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: "+m" (v->counter), "=qm" (c)
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: : "memory");
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return c != 0;
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}
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/**
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* atomic_add_negative - add and test if negative
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* @v: pointer of type atomic_t
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* @i: integer value to add
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*
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* Atomically adds @i to @v and returns true
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* if the result is negative, or false when
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* result is greater than or equal to zero.
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*/
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static inline int atomic_add_negative(int i, atomic_t *v)
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{
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unsigned char c;
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asm volatile(LOCK_PREFIX "addl %2,%0; sets %1"
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: "+m" (v->counter), "=qm" (c)
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: "ir" (i) : "memory");
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return c;
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}
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/**
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* atomic_add_return - add integer and return
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* @v: pointer of type atomic_t
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* @i: integer value to add
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*
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* Atomically adds @i to @v and returns @i + @v
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*/
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static inline int atomic_add_return(int i, atomic_t *v)
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{
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int __i;
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#ifdef CONFIG_M386
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unsigned long flags;
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if (unlikely(boot_cpu_data.x86 <= 3))
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goto no_xadd;
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#endif
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/* Modern 486+ processor */
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__i = i;
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asm volatile(LOCK_PREFIX "xaddl %0, %1"
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: "+r" (i), "+m" (v->counter)
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: : "memory");
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return i + __i;
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#ifdef CONFIG_M386
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no_xadd: /* Legacy 386 processor */
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local_irq_save(flags);
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__i = atomic_read(v);
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atomic_set(v, i + __i);
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local_irq_restore(flags);
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return i + __i;
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#endif
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}
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/**
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* atomic_sub_return - subtract integer and return
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* @v: pointer of type atomic_t
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* @i: integer value to subtract
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*
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* Atomically subtracts @i from @v and returns @v - @i
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*/
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static inline int atomic_sub_return(int i, atomic_t *v)
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{
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return atomic_add_return(-i, v);
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}
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static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
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{
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return cmpxchg(&v->counter, old, new);
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}
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static inline int atomic_xchg(atomic_t *v, int new)
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{
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return xchg(&v->counter, new);
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}
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/**
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* atomic_add_unless - add unless the number is already a given value
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* @v: pointer of type atomic_t
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* @a: the amount to add to v...
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* @u: ...unless v is equal to u.
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*
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* Atomically adds @a to @v, so long as @v was not already @u.
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* Returns non-zero if @v was not @u, and zero otherwise.
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*/
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static inline int atomic_add_unless(atomic_t *v, int a, int u)
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{
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int c, old;
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c = atomic_read(v);
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for (;;) {
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if (unlikely(c == (u)))
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break;
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old = atomic_cmpxchg((v), c, c + (a));
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if (likely(old == c))
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break;
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c = old;
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}
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return c != (u);
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}
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#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
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#define atomic_inc_return(v) (atomic_add_return(1, v))
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#define atomic_dec_return(v) (atomic_sub_return(1, v))
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/* These are x86-specific, used by some header files */
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#define atomic_clear_mask(mask, addr) \
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asm volatile(LOCK_PREFIX "andl %0,%1" \
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: : "r" (~(mask)), "m" (*(addr)) : "memory")
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#define atomic_set_mask(mask, addr) \
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asm volatile(LOCK_PREFIX "orl %0,%1" \
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: : "r" (mask), "m" (*(addr)) : "memory")
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/* Atomic operations are already serializing on x86 */
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#define smp_mb__before_atomic_dec() barrier()
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#define smp_mb__after_atomic_dec() barrier()
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#define smp_mb__before_atomic_inc() barrier()
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#define smp_mb__after_atomic_inc() barrier()
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/* An 64bit atomic type */
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typedef struct {
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u64 __aligned(8) counter;
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} atomic64_t;
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extern u64 atomic64_cmpxchg(atomic64_t *ptr, u64 old_val, u64 new_val);
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/**
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* atomic64_xchg - xchg atomic64 variable
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* @ptr: pointer to type atomic64_t
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* @new_val: value to assign
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*
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* Atomically xchgs the value of @ptr to @new_val and returns
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* the old value.
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*/
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static inline long long atomic64_xchg(atomic64_t *v, long long n)
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{
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long long o;
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unsigned high = (unsigned)(n >> 32);
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unsigned low = (unsigned)n;
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asm volatile(
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"1: \n\t"
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"cmpxchg8b (%%esi) \n\t"
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"jnz 1b \n\t"
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:"=&A" (o)
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:"S" (v), "b" (low), "c" (high)
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: "memory", "cc");
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return o;
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}
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/**
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* atomic64_set - set atomic64 variable
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* @ptr: pointer to type atomic64_t
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* @new_val: value to assign
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*
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* Atomically sets the value of @ptr to @new_val.
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*/
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static inline void atomic64_set(atomic64_t *v, long long i)
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{
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unsigned high = (unsigned)(i >> 32);
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unsigned low = (unsigned)i;
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asm volatile (
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"1: \n\t"
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"cmpxchg8b (%%esi) \n\t"
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"jnz 1b \n\t"
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:
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:"S" (v), "b" (low), "c" (high)
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: "eax", "edx", "memory", "cc");
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}
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/**
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* atomic64_read - read atomic64 variable
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* @ptr: pointer to type atomic64_t
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*
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* Atomically reads the value of @ptr and returns it.
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*/
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static inline u64 atomic64_read(atomic64_t *ptr)
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{
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u64 res;
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/*
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* Note, we inline this atomic64_t primitive because
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* it only clobbers EAX/EDX and leaves the others
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* untouched. We also (somewhat subtly) rely on the
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* fact that cmpxchg8b returns the current 64-bit value
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* of the memory location we are touching:
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*/
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asm volatile(
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"mov %%ebx, %%eax\n\t"
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"mov %%ecx, %%edx\n\t"
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LOCK_PREFIX "cmpxchg8b %1\n"
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: "=&A" (res)
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: "m" (*ptr)
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);
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return res;
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}
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/**
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* atomic64_add_return - add and return
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* @delta: integer value to add
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* @ptr: pointer to type atomic64_t
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*
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* Atomically adds @delta to @ptr and returns @delta + *@ptr
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*/
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extern u64 atomic64_add_return(u64 delta, atomic64_t *ptr);
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/*
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* Other variants with different arithmetic operators:
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*/
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extern u64 atomic64_sub_return(u64 delta, atomic64_t *ptr);
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extern u64 atomic64_inc_return(atomic64_t *ptr);
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extern u64 atomic64_dec_return(atomic64_t *ptr);
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/**
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* atomic64_add - add integer to atomic64 variable
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* @delta: integer value to add
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* @ptr: pointer to type atomic64_t
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*
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* Atomically adds @delta to @ptr.
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*/
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extern void atomic64_add(u64 delta, atomic64_t *ptr);
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/**
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* atomic64_sub - subtract the atomic64 variable
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* @delta: integer value to subtract
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* @ptr: pointer to type atomic64_t
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*
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* Atomically subtracts @delta from @ptr.
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*/
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extern void atomic64_sub(u64 delta, atomic64_t *ptr);
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/**
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* atomic64_sub_and_test - subtract value from variable and test result
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* @delta: integer value to subtract
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* @ptr: pointer to type atomic64_t
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*
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* Atomically subtracts @delta from @ptr and returns
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* true if the result is zero, or false for all
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* other cases.
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*/
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extern int atomic64_sub_and_test(u64 delta, atomic64_t *ptr);
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/**
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* atomic64_inc - increment atomic64 variable
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* @ptr: pointer to type atomic64_t
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*
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* Atomically increments @ptr by 1.
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*/
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extern void atomic64_inc(atomic64_t *ptr);
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/**
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* atomic64_dec - decrement atomic64 variable
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* @ptr: pointer to type atomic64_t
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*
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* Atomically decrements @ptr by 1.
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*/
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extern void atomic64_dec(atomic64_t *ptr);
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/**
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* atomic64_dec_and_test - decrement and test
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* @ptr: pointer to type atomic64_t
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*
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* Atomically decrements @ptr by 1 and
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* returns true if the result is 0, or false for all other
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* cases.
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*/
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extern int atomic64_dec_and_test(atomic64_t *ptr);
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/**
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* atomic64_inc_and_test - increment and test
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* @ptr: pointer to type atomic64_t
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*
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* Atomically increments @ptr by 1
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* and returns true if the result is zero, or false for all
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* other cases.
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*/
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extern int atomic64_inc_and_test(atomic64_t *ptr);
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/**
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* atomic64_add_negative - add and test if negative
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* @delta: integer value to add
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* @ptr: pointer to type atomic64_t
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*
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* Atomically adds @delta to @ptr and returns true
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* if the result is negative, or false when
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* result is greater than or equal to zero.
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*/
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extern int atomic64_add_negative(u64 delta, atomic64_t *ptr);
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#include <asm-generic/atomic-long.h>
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#endif /* _ASM_X86_ATOMIC_32_H */
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