x86: implement atomic64_t on 32-bit (9b194e83) · Commits · 方亚芬 / linux

arch/x86/include/asm/atomic_32.h

+218 −0

Original line number	Diff line number	Diff line
		@@ -255,5 +255,223 @@ static inline int atomic_add_unless(atomic_t *v, int a, int u)
		#define smp_mb__before_atomic_inc() barrier()
		#define smp_mb__after_atomic_inc() barrier()

		/* An 64bit atomic type */

		typedef struct {
		unsigned long long counter;
		} atomic64_t;

		#define ATOMIC64_INIT(val) { (val) }

		/**
		* atomic64_read - read atomic64 variable
		* @v: pointer of type atomic64_t
		*
		* Atomically reads the value of @v.
		* Doesn't imply a read memory barrier.
		*/
		#define __atomic64_read(ptr) ((ptr)->counter)

		static inline unsigned long long
		cmpxchg8b(unsigned long long *ptr, unsigned long long old, unsigned long long new)
		{
		asm volatile(

		LOCK_PREFIX "cmpxchg8b (%[ptr])\n"

		: "=A" (old)

		: [ptr] "D" (ptr),
		"A" (old),
		"b" (ll_low(new)),
		"c" (ll_high(new))

		: "memory");

		return old;
		}

		static inline unsigned long long
		atomic64_cmpxchg(atomic64_t *ptr, unsigned long long old_val,
		unsigned long long new_val)
		{
		return cmpxchg8b(&ptr->counter, old_val, new_val);
		}

		/**
		* atomic64_set - set atomic64 variable
		* @ptr: pointer to type atomic64_t
		* @new_val: value to assign
		*
		* Atomically sets the value of @ptr to @new_val.
		*/
		static inline void atomic64_set(atomic64_t *ptr, unsigned long long new_val)
		{
		unsigned long long old_val;

		do {
		old_val = atomic_read(ptr);
		} while (atomic64_cmpxchg(ptr, old_val, new_val) != old_val);
		}

		/**
		* atomic64_read - read atomic64 variable
		* @ptr: pointer to type atomic64_t
		*
		* Atomically reads the value of @ptr and returns it.
		*/
		static inline unsigned long long atomic64_read(atomic64_t *ptr)
		{
		unsigned long long curr_val;

		do {
		curr_val = __atomic64_read(ptr);
		} while (atomic64_cmpxchg(ptr, curr_val, curr_val) != curr_val);

		return curr_val;
		}

		/**
		* atomic64_add_return - add and return
		* @delta: integer value to add
		* @ptr: pointer to type atomic64_t
		*
		* Atomically adds @delta to @ptr and returns @delta + *@ptr
		*/
		static inline unsigned long long
		atomic64_add_return(unsigned long long delta, atomic64_t *ptr)
		{
		unsigned long long old_val, new_val;

		do {
		old_val = atomic_read(ptr);
		new_val = old_val + delta;

		} while (atomic64_cmpxchg(ptr, old_val, new_val) != old_val);

		return new_val;
		}

		static inline long atomic64_sub_return(unsigned long long delta, atomic64_t *ptr)
		{
		return atomic64_add_return(-delta, ptr);
		}

		static inline long atomic64_inc_return(atomic64_t *ptr)
		{
		return atomic64_add_return(1, ptr);
		}

		static inline long atomic64_dec_return(atomic64_t *ptr)
		{
		return atomic64_sub_return(1, ptr);
		}

		/**
		* atomic64_add - add integer to atomic64 variable
		* @delta: integer value to add
		* @ptr: pointer to type atomic64_t
		*
		* Atomically adds @delta to @ptr.
		*/
		static inline void atomic64_add(unsigned long long delta, atomic64_t *ptr)
		{
		atomic64_add_return(delta, ptr);
		}

		/**
		* atomic64_sub - subtract the atomic64 variable
		* @delta: integer value to subtract
		* @ptr: pointer to type atomic64_t
		*
		* Atomically subtracts @delta from @ptr.
		*/
		static inline void atomic64_sub(unsigned long long delta, atomic64_t *ptr)
		{
		atomic64_add(-delta, ptr);
		}

		/**
		* atomic64_sub_and_test - subtract value from variable and test result
		* @delta: integer value to subtract
		* @ptr: pointer to type atomic64_t
		*
		* Atomically subtracts @delta from @ptr and returns
		* true if the result is zero, or false for all
		* other cases.
		*/
		static inline int
		atomic64_sub_and_test(unsigned long long delta, atomic64_t *ptr)
		{
		unsigned long long old_val = atomic64_sub_return(delta, ptr);

		return old_val == 0;
		}

		/**
		* atomic64_inc - increment atomic64 variable
		* @ptr: pointer to type atomic64_t
		*
		* Atomically increments @ptr by 1.
		*/
		static inline void atomic64_inc(atomic64_t *ptr)
		{
		atomic64_add(1, ptr);
		}

		/**
		* atomic64_dec - decrement atomic64 variable
		* @ptr: pointer to type atomic64_t
		*
		* Atomically decrements @ptr by 1.
		*/
		static inline void atomic64_dec(atomic64_t *ptr)
		{
		atomic64_sub(1, ptr);
		}

		/**
		* atomic64_dec_and_test - decrement and test
		* @ptr: pointer to type atomic64_t
		*
		* Atomically decrements @ptr by 1 and
		* returns true if the result is 0, or false for all other
		* cases.
		*/
		static inline int atomic64_dec_and_test(atomic64_t *ptr)
		{
		return atomic64_sub_and_test(1, ptr);
		}

		/**
		* atomic64_inc_and_test - increment and test
		* @ptr: pointer to type atomic64_t
		*
		* Atomically increments @ptr by 1
		* and returns true if the result is zero, or false for all
		* other cases.
		*/
		static inline int atomic64_inc_and_test(atomic64_t *ptr)
		{
		return atomic64_sub_and_test(-1, ptr);
		}

		/**
		* atomic64_add_negative - add and test if negative
		* @delta: integer value to add
		* @ptr: pointer to type atomic64_t
		*
		* Atomically adds @delta to @ptr and returns true
		* if the result is negative, or false when
		* result is greater than or equal to zero.
		*/
		static inline int
		atomic64_add_negative(unsigned long long delta, atomic64_t *ptr)
		{
		long long old_val = atomic64_add_return(delta, ptr);

		return old_val < 0;
		}

		#include <asm-generic/atomic.h>
		#endif /* _ASM_X86_ATOMIC_32_H */