1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
237 lines
5.1 KiB
C
237 lines
5.1 KiB
C
#ifndef __ARCH_I386_ATOMIC__
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#define __ARCH_I386_ATOMIC__
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#include <linux/config.h>
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#include <linux/compiler.h>
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#include <asm/processor.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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#ifdef CONFIG_SMP
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#define LOCK "lock ; "
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#else
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#define LOCK ""
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#endif
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/*
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* Make sure gcc doesn't try to be clever and move things around
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* on us. We need to use _exactly_ the address the user gave us,
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* not some alias that contains the same information.
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*/
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typedef struct { volatile int counter; } atomic_t;
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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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#define atomic_read(v) ((v)->counter)
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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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#define atomic_set(v,i) (((v)->counter) = (i))
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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__(
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LOCK "addl %1,%0"
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:"=m" (v->counter)
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:"ir" (i), "m" (v->counter));
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}
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/**
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* atomic_sub - subtract the 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__(
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LOCK "subl %1,%0"
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:"=m" (v->counter)
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:"ir" (i), "m" (v->counter));
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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__(
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LOCK "subl %2,%0; sete %1"
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:"=m" (v->counter), "=qm" (c)
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:"ir" (i), "m" (v->counter) : "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__(
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LOCK "incl %0"
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:"=m" (v->counter)
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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__(
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LOCK "decl %0"
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:"=m" (v->counter)
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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__(
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LOCK "decl %0; sete %1"
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:"=m" (v->counter), "=qm" (c)
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:"m" (v->counter) : "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__(
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LOCK "incl %0; sete %1"
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:"=m" (v->counter), "=qm" (c)
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:"m" (v->counter) : "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__(
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LOCK "addl %2,%0; sets %1"
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:"=m" (v->counter), "=qm" (c)
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:"ir" (i), "m" (v->counter) : "memory");
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return c;
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}
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/**
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* atomic_add_return - add 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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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__(
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LOCK "xaddl %0, %1;"
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:"=r"(i)
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:"m"(v->counter), "0"(i));
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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_disable();
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__i = atomic_read(v);
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atomic_set(v, i + __i);
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local_irq_enable();
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return i + __i;
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#endif
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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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#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 "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 "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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#endif
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