x86: implement atomic64_t on 32-bit
Impact: new API Implement the atomic64_t APIs on 32-bit as well. Will be used by the performance counters code. Signed-off-by: Ingo Molnar <mingo@elte.hu>
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@ -255,5 +255,223 @@ static inline int atomic_add_unless(atomic_t *v, int a, int u)
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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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unsigned long long counter;
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} atomic64_t;
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#define ATOMIC64_INIT(val) { (val) }
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/**
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* atomic64_read - read atomic64 variable
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* @v: pointer of type atomic64_t
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*
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* Atomically reads the value of @v.
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* Doesn't imply a read memory barrier.
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*/
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#define __atomic64_read(ptr) ((ptr)->counter)
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static inline unsigned long long
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cmpxchg8b(unsigned long long *ptr, unsigned long long old, unsigned long long new)
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{
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asm volatile(
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LOCK_PREFIX "cmpxchg8b (%[ptr])\n"
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: "=A" (old)
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: [ptr] "D" (ptr),
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"A" (old),
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"b" (ll_low(new)),
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"c" (ll_high(new))
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: "memory");
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return old;
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}
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static inline unsigned long long
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atomic64_cmpxchg(atomic64_t *ptr, unsigned long long old_val,
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unsigned long long new_val)
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{
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return cmpxchg8b(&ptr->counter, old_val, new_val);
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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 *ptr, unsigned long long new_val)
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{
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unsigned long long old_val;
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do {
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old_val = atomic_read(ptr);
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} while (atomic64_cmpxchg(ptr, old_val, new_val) != old_val);
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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 unsigned long long atomic64_read(atomic64_t *ptr)
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{
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unsigned long long curr_val;
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do {
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curr_val = __atomic64_read(ptr);
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} while (atomic64_cmpxchg(ptr, curr_val, curr_val) != curr_val);
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return curr_val;
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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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static inline unsigned long long
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atomic64_add_return(unsigned long long delta, atomic64_t *ptr)
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{
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unsigned long long old_val, new_val;
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do {
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old_val = atomic_read(ptr);
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new_val = old_val + delta;
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} while (atomic64_cmpxchg(ptr, old_val, new_val) != old_val);
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return new_val;
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}
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static inline long atomic64_sub_return(unsigned long long delta, atomic64_t *ptr)
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{
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return atomic64_add_return(-delta, ptr);
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}
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static inline long atomic64_inc_return(atomic64_t *ptr)
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{
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return atomic64_add_return(1, ptr);
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}
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static inline long atomic64_dec_return(atomic64_t *ptr)
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{
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return atomic64_sub_return(1, ptr);
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}
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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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static inline void atomic64_add(unsigned long long delta, atomic64_t *ptr)
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{
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atomic64_add_return(delta, ptr);
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}
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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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static inline void atomic64_sub(unsigned long long delta, atomic64_t *ptr)
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{
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atomic64_add(-delta, ptr);
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}
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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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static inline int
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atomic64_sub_and_test(unsigned long long delta, atomic64_t *ptr)
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{
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unsigned long long old_val = atomic64_sub_return(delta, ptr);
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return old_val == 0;
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}
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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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static inline void atomic64_inc(atomic64_t *ptr)
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{
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atomic64_add(1, ptr);
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}
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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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static inline void atomic64_dec(atomic64_t *ptr)
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{
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atomic64_sub(1, ptr);
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}
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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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static inline int atomic64_dec_and_test(atomic64_t *ptr)
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{
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return atomic64_sub_and_test(1, ptr);
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}
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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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static inline int atomic64_inc_and_test(atomic64_t *ptr)
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{
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return atomic64_sub_and_test(-1, ptr);
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}
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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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static inline int
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atomic64_add_negative(unsigned long long delta, atomic64_t *ptr)
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{
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long long old_val = atomic64_add_return(delta, ptr);
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return old_val < 0;
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}
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#include <asm-generic/atomic.h>
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#endif /* _ASM_X86_ATOMIC_32_H */
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