203 lines
5.3 KiB
C
203 lines
5.3 KiB
C
#ifndef __PRIVATE_ASM_I386_ATOMIC__
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#define __PRIVATE_ASM_I386_ATOMIC__
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/* Optimization barrier */
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/* The "volatile" is due to gcc bugs */
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#define barrier() __asm__ __volatile__("": : :"memory")
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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 LOCK "lock ; "
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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; } ncpt_atomic_t;
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#define NCPT_ATOMIC_INIT(i) { (i) }
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/**
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* ncpt_atomic_read - read atomic variable
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* @v: pointer of type ncpt_atomic_t
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*
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* Atomically reads the value of @v. Note that the guaranteed
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* useful range of an ncpt_atomic_t is only 24 bits.
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*/
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#define ncpt_atomic_read(v) ((v)->counter)
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/**
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* ncpt_atomic_set - set atomic variable
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* @v: pointer of type ncpt_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. Note that the guaranteed
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* useful range of an ncpt_atomic_t is only 24 bits.
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*/
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#define ncpt_atomic_set(v,i) (((v)->counter) = (i))
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/**
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* ncpt_atomic_add - add integer to atomic variable
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* @i: integer value to add
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* @v: pointer of type ncpt_atomic_t
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*
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* Atomically adds @i to @v. Note that the guaranteed useful range
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* of an ncpt_atomic_t is only 24 bits.
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*/
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static __inline__ void ncpt_atomic_add(int i, ncpt_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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* ncpt_atomic_sub - subtract the atomic variable
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* @i: integer value to subtract
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* @v: pointer of type ncpt_atomic_t
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*
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* Atomically subtracts @i from @v. Note that the guaranteed
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* useful range of an ncpt_atomic_t is only 24 bits.
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*/
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static __inline__ void ncpt_atomic_sub(int i, ncpt_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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* ncpt_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 ncpt_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. Note that the guaranteed
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* useful range of an ncpt_atomic_t is only 24 bits.
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*/
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static __inline__ int ncpt_atomic_sub_and_test(int i, ncpt_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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* ncpt_atomic_inc - increment atomic variable
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* @v: pointer of type ncpt_atomic_t
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*
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* Atomically increments @v by 1. Note that the guaranteed
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* useful range of an ncpt_atomic_t is only 24 bits.
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*/
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static __inline__ void ncpt_atomic_inc(ncpt_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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* ncpt_atomic_dec - decrement atomic variable
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* @v: pointer of type ncpt_atomic_t
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*
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* Atomically decrements @v by 1. Note that the guaranteed
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* useful range of an ncpt_atomic_t is only 24 bits.
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*/
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static __inline__ void ncpt_atomic_dec(ncpt_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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* ncpt_atomic_dec_and_test - decrement and test
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* @v: pointer of type ncpt_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. Note that the guaranteed
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* useful range of an ncpt_atomic_t is only 24 bits.
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*/
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static __inline__ int ncpt_atomic_dec_and_test(ncpt_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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* ncpt_atomic_inc_and_test - increment and test
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* @v: pointer of type ncpt_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. Note that the guaranteed
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* useful range of an ncpt_atomic_t is only 24 bits.
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*/
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static __inline__ int ncpt_atomic_inc_and_test(ncpt_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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* ncpt_atomic_add_negative - add and test if negative
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* @v: pointer of type ncpt_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. Note that the guaranteed
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* useful range of an ncpt_atomic_t is only 24 bits.
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*/
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static __inline__ int ncpt_atomic_add_negative(int i, ncpt_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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/* These are x86-specific, used by some header files */
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#define ncpt_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 ncpt_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_ncpt_atomic_dec() barrier()
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#define smp_mb__after_ncpt_atomic_dec() barrier()
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#define smp_mb__before_ncpt_atomic_inc() barrier()
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#define smp_mb__after_ncpt_atomic_inc() barrier()
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#endif
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