arch/x86/include/asm/atomic_32.h - kernel/prism - Git at Google

 #ifndef _ASM_X86_ATOMIC_32_H
 #define _ASM_X86_ATOMIC_32_H

 #include <linux/compiler.h>
 #include <linux/types.h>
 #include <asm/processor.h>
 #include <asm/cmpxchg.h>

 /*
  * Atomic operations that C can't guarantee us.  Useful for
  * resource counting etc..
  */

 #define ATOMIC_INIT(i)	{ (i) }

 /**
  * atomic_read - read atomic variable
  * @v: pointer of type atomic_t
  *
  * Atomically reads the value of @v.
  */
 static inline int atomic_read(const atomic_t *v)
 {
 	return v->counter;
 }

 /**
  * atomic_set - set atomic variable
  * @v: pointer of type atomic_t
  * @i: required value
  *
  * Atomically sets the value of @v to @i.
  */
 static inline void atomic_set(atomic_t *v, int i)
 {
 	v->counter = i;
 }

 /**
  * atomic_add - add integer to atomic variable
  * @i: integer value to add
  * @v: pointer of type atomic_t
  *
  * Atomically adds @i to @v.
  */
 static inline void atomic_add(int i, atomic_t *v)
 {
 	asm volatile(LOCK_PREFIX "addl %1,%0"
 		     : "+m" (v->counter)
 		     : "ir" (i));
 }

 /**
  * atomic_sub - subtract integer from atomic variable
  * @i: integer value to subtract
  * @v: pointer of type atomic_t
  *
  * Atomically subtracts @i from @v.
  */
 static inline void atomic_sub(int i, atomic_t *v)
 {
 	asm volatile(LOCK_PREFIX "subl %1,%0"
 		     : "+m" (v->counter)
 		     : "ir" (i));
 }

 /**
  * atomic_sub_and_test - subtract value from variable and test result
  * @i: integer value to subtract
  * @v: pointer of type atomic_t
  *
  * Atomically subtracts @i from @v and returns
  * true if the result is zero, or false for all
  * other cases.
  */
 static inline int atomic_sub_and_test(int i, atomic_t *v)
 {
 	unsigned char c;

 	asm volatile(LOCK_PREFIX "subl %2,%0; sete %1"
 		     : "+m" (v->counter), "=qm" (c)
 		     : "ir" (i) : "memory");
 	return c;
 }

 /**
  * atomic_inc - increment atomic variable
  * @v: pointer of type atomic_t
  *
  * Atomically increments @v by 1.
  */
 static inline void atomic_inc(atomic_t *v)
 {
 	asm volatile(LOCK_PREFIX "incl %0"
 		     : "+m" (v->counter));
 }

 /**
  * atomic_dec - decrement atomic variable
  * @v: pointer of type atomic_t
  *
  * Atomically decrements @v by 1.
  */
 static inline void atomic_dec(atomic_t *v)
 {
 	asm volatile(LOCK_PREFIX "decl %0"
 		     : "+m" (v->counter));
 }

 /**
  * atomic_dec_and_test - decrement and test
  * @v: pointer of type atomic_t
  *
  * Atomically decrements @v by 1 and
  * returns true if the result is 0, or false for all other
  * cases.
  */
 static inline int atomic_dec_and_test(atomic_t *v)
 {
 	unsigned char c;

 	asm volatile(LOCK_PREFIX "decl %0; sete %1"
 		     : "+m" (v->counter), "=qm" (c)
 		     : : "memory");
 	return c != 0;
 }

 /**
  * atomic_inc_and_test - increment and test
  * @v: pointer of type atomic_t
  *
  * Atomically increments @v by 1
  * and returns true if the result is zero, or false for all
  * other cases.
  */
 static inline int atomic_inc_and_test(atomic_t *v)
 {
 	unsigned char c;

 	asm volatile(LOCK_PREFIX "incl %0; sete %1"
 		     : "+m" (v->counter), "=qm" (c)
 		     : : "memory");
 	return c != 0;
 }

 /**
  * atomic_add_negative - add and test if negative
  * @v: pointer of type atomic_t
  * @i: integer value to add
  *
  * Atomically adds @i to @v and returns true
  * if the result is negative, or false when
  * result is greater than or equal to zero.
  */
 static inline int atomic_add_negative(int i, atomic_t *v)
 {
 	unsigned char c;

 	asm volatile(LOCK_PREFIX "addl %2,%0; sets %1"
 		     : "+m" (v->counter), "=qm" (c)
 		     : "ir" (i) : "memory");
 	return c;
 }

 /**
  * atomic_add_return - add integer and return
  * @v: pointer of type atomic_t
  * @i: integer value to add
  *
  * Atomically adds @i to @v and returns @i + @v
  */
 static inline int atomic_add_return(int i, atomic_t *v)
 {
 	int __i;
 #ifdef CONFIG_M386
 	unsigned long flags;
 	if (unlikely(boot_cpu_data.x86 <= 3))
 		goto no_xadd;
 #endif
 	/* Modern 486+ processor */
 	__i = i;
 	asm volatile(LOCK_PREFIX "xaddl %0, %1"
 		     : "+r" (i), "+m" (v->counter)
 		     : : "memory");
 	return i + __i;

 #ifdef CONFIG_M386
 no_xadd: /* Legacy 386 processor */
 	local_irq_save(flags);
 	__i = atomic_read(v);
 	atomic_set(v, i + __i);
 	local_irq_restore(flags);
 	return i + __i;
 #endif
 }

 /**
  * atomic_sub_return - subtract integer and return
  * @v: pointer of type atomic_t
  * @i: integer value to subtract
  *
  * Atomically subtracts @i from @v and returns @v - @i
  */
 static inline int atomic_sub_return(int i, atomic_t *v)
 {
 	return atomic_add_return(-i, v);
 }

 static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
 {
 	return cmpxchg(&v->counter, old, new);
 }

 static inline int atomic_xchg(atomic_t *v, int new)
 {
 	return xchg(&v->counter, new);
 }

 /**
  * atomic_add_unless - add unless the number is already a given value
  * @v: pointer of type atomic_t
  * @a: the amount to add to v...
  * @u: ...unless v is equal to u.
  *
  * Atomically adds @a to @v, so long as @v was not already @u.
  * Returns non-zero if @v was not @u, and zero otherwise.
  */
 static inline int atomic_add_unless(atomic_t *v, int a, int u)
 {
 	int c, old;
 	c = atomic_read(v);
 	for (;;) {
 		if (unlikely(c == (u)))
 			break;
 		old = atomic_cmpxchg((v), c, c + (a));
 		if (likely(old == c))
 			break;
 		c = old;
 	}
 	return c != (u);
 }

 #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)

 #define atomic_inc_return(v)  (atomic_add_return(1, v))
 #define atomic_dec_return(v)  (atomic_sub_return(1, v))

 /* These are x86-specific, used by some header files */
 #define atomic_clear_mask(mask, addr)				\
 	asm volatile(LOCK_PREFIX "andl %0,%1"			\
 		     : : "r" (~(mask)), "m" (*(addr)) : "memory")

 #define atomic_set_mask(mask, addr)				\
 	asm volatile(LOCK_PREFIX "orl %0,%1"				\
 		     : : "r" (mask), "m" (*(addr)) : "memory")

 /* Atomic operations are already serializing on x86 */
 #define smp_mb__before_atomic_dec()	barrier()
 #define smp_mb__after_atomic_dec()	barrier()
 #define smp_mb__before_atomic_inc()	barrier()
 #define smp_mb__after_atomic_inc()	barrier()

 /* An 64bit atomic type */

 typedef struct {
 	u64 __aligned(8) counter;
 } atomic64_t;

 #define ATOMIC64_INIT(val)	{ (val) }

 extern u64 atomic64_cmpxchg(atomic64_t *ptr, u64 old_val, u64 new_val);

 /**
  * atomic64_xchg - xchg atomic64 variable
  * @ptr:      pointer to type atomic64_t
  * @new_val:  value to assign
  *
  * Atomically xchgs the value of @ptr to @new_val and returns
  * the old value.
  */
 extern u64 atomic64_xchg(atomic64_t *ptr, u64 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.
  */
 extern void atomic64_set(atomic64_t *ptr, u64 new_val);

 /**
  * atomic64_read - read atomic64 variable
  * @ptr:      pointer to type atomic64_t
  *
  * Atomically reads the value of @ptr and returns it.
  */
 static inline u64 atomic64_read(atomic64_t *ptr)
 {
 	u64 res;

 	/*
 	 * Note, we inline this atomic64_t primitive because
 	 * it only clobbers EAX/EDX and leaves the others
 	 * untouched. We also (somewhat subtly) rely on the
 	 * fact that cmpxchg8b returns the current 64-bit value
 	 * of the memory location we are touching:
 	 */
 	asm volatile(
 		"mov %%ebx, %%eax\n\t"
 		"mov %%ecx, %%edx\n\t"
 		LOCK_PREFIX "cmpxchg8b %1\n"
 			: "=&A" (res)
 			: "m" (*ptr)
 		);

 	return res;
 }

 extern u64 atomic64_read(atomic64_t *ptr);

 /**
  * 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
  */
 extern u64 atomic64_add_return(u64 delta, atomic64_t *ptr);

 /*
  * Other variants with different arithmetic operators:
  */
 extern u64 atomic64_sub_return(u64 delta, atomic64_t *ptr);
 extern u64 atomic64_inc_return(atomic64_t *ptr);
 extern u64 atomic64_dec_return(atomic64_t *ptr);

 /**
  * atomic64_add - add integer to atomic64 variable
  * @delta: integer value to add
  * @ptr:   pointer to type atomic64_t
  *
  * Atomically adds @delta to @ptr.
  */
 extern void atomic64_add(u64 delta, atomic64_t *ptr);

 /**
  * atomic64_sub - subtract the atomic64 variable
  * @delta: integer value to subtract
  * @ptr:   pointer to type atomic64_t
  *
  * Atomically subtracts @delta from @ptr.
  */
 extern void atomic64_sub(u64 delta, atomic64_t *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.
  */
 extern int atomic64_sub_and_test(u64 delta, atomic64_t *ptr);

 /**
  * atomic64_inc - increment atomic64 variable
  * @ptr: pointer to type atomic64_t
  *
  * Atomically increments @ptr by 1.
  */
 extern void atomic64_inc(atomic64_t *ptr);

 /**
  * atomic64_dec - decrement atomic64 variable
  * @ptr: pointer to type atomic64_t
  *
  * Atomically decrements @ptr by 1.
  */
 extern void atomic64_dec(atomic64_t *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.
  */
 extern int atomic64_dec_and_test(atomic64_t *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.
  */
 extern int atomic64_inc_and_test(atomic64_t *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.
  */
 extern int atomic64_add_negative(u64 delta, atomic64_t *ptr);

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

	#include <linux/compiler.h>
	#include <linux/types.h>
	#include <asm/processor.h>
	#include <asm/cmpxchg.h>

	/*
	* Atomic operations that C can't guarantee us. Useful for
	* resource counting etc..
	*/

	#define ATOMIC_INIT(i) { (i) }

	/**
	* atomic_read - read atomic variable
	* @v: pointer of type atomic_t
	*
	* Atomically reads the value of @v.
	*/
	static inline int atomic_read(const atomic_t *v)
	{
	return v->counter;
	}

	/**
	* atomic_set - set atomic variable
	* @v: pointer of type atomic_t
	* @i: required value
	*
	* Atomically sets the value of @v to @i.
	*/
	static inline void atomic_set(atomic_t *v, int i)
	{
	v->counter = i;
	}

	/**
	* atomic_add - add integer to atomic variable
	* @i: integer value to add
	* @v: pointer of type atomic_t
	*
	* Atomically adds @i to @v.
	*/
	static inline void atomic_add(int i, atomic_t *v)
	{
	asm volatile(LOCK_PREFIX "addl %1,%0"
	: "+m" (v->counter)
	: "ir" (i));
	}

	/**
	* atomic_sub - subtract integer from atomic variable
	* @i: integer value to subtract
	* @v: pointer of type atomic_t
	*
	* Atomically subtracts @i from @v.
	*/
	static inline void atomic_sub(int i, atomic_t *v)
	{
	asm volatile(LOCK_PREFIX "subl %1,%0"
	: "+m" (v->counter)
	: "ir" (i));
	}

	/**
	* atomic_sub_and_test - subtract value from variable and test result
	* @i: integer value to subtract
	* @v: pointer of type atomic_t
	*
	* Atomically subtracts @i from @v and returns
	* true if the result is zero, or false for all
	* other cases.
	*/
	static inline int atomic_sub_and_test(int i, atomic_t *v)
	{
	unsigned char c;

	asm volatile(LOCK_PREFIX "subl %2,%0; sete %1"
	: "+m" (v->counter), "=qm" (c)
	: "ir" (i) : "memory");
	return c;
	}

	/**
	* atomic_inc - increment atomic variable
	* @v: pointer of type atomic_t
	*
	* Atomically increments @v by 1.
	*/
	static inline void atomic_inc(atomic_t *v)
	{
	asm volatile(LOCK_PREFIX "incl %0"
	: "+m" (v->counter));
	}

	/**
	* atomic_dec - decrement atomic variable
	* @v: pointer of type atomic_t
	*
	* Atomically decrements @v by 1.
	*/
	static inline void atomic_dec(atomic_t *v)
	{
	asm volatile(LOCK_PREFIX "decl %0"
	: "+m" (v->counter));
	}

	/**
	* atomic_dec_and_test - decrement and test
	* @v: pointer of type atomic_t
	*
	* Atomically decrements @v by 1 and
	* returns true if the result is 0, or false for all other
	* cases.
	*/
	static inline int atomic_dec_and_test(atomic_t *v)
	{
	unsigned char c;

	asm volatile(LOCK_PREFIX "decl %0; sete %1"
	: "+m" (v->counter), "=qm" (c)
	: : "memory");
	return c != 0;
	}

	/**
	* atomic_inc_and_test - increment and test
	* @v: pointer of type atomic_t
	*
	* Atomically increments @v by 1
	* and returns true if the result is zero, or false for all
	* other cases.
	*/
	static inline int atomic_inc_and_test(atomic_t *v)
	{
	unsigned char c;

	asm volatile(LOCK_PREFIX "incl %0; sete %1"
	: "+m" (v->counter), "=qm" (c)
	: : "memory");
	return c != 0;
	}

	/**
	* atomic_add_negative - add and test if negative
	* @v: pointer of type atomic_t
	* @i: integer value to add
	*
	* Atomically adds @i to @v and returns true
	* if the result is negative, or false when
	* result is greater than or equal to zero.
	*/
	static inline int atomic_add_negative(int i, atomic_t *v)
	{
	unsigned char c;

	asm volatile(LOCK_PREFIX "addl %2,%0; sets %1"
	: "+m" (v->counter), "=qm" (c)
	: "ir" (i) : "memory");
	return c;
	}

	/**
	* atomic_add_return - add integer and return
	* @v: pointer of type atomic_t
	* @i: integer value to add
	*
	* Atomically adds @i to @v and returns @i + @v
	*/
	static inline int atomic_add_return(int i, atomic_t *v)
	{
	int __i;
	#ifdef CONFIG_M386
	unsigned long flags;
	if (unlikely(boot_cpu_data.x86 <= 3))
	goto no_xadd;
	#endif
	/* Modern 486+ processor */
	__i = i;
	asm volatile(LOCK_PREFIX "xaddl %0, %1"
	: "+r" (i), "+m" (v->counter)
	: : "memory");
	return i + __i;

	#ifdef CONFIG_M386
	no_xadd: /* Legacy 386 processor */
	local_irq_save(flags);
	__i = atomic_read(v);
	atomic_set(v, i + __i);
	local_irq_restore(flags);
	return i + __i;
	#endif
	}

	/**
	* atomic_sub_return - subtract integer and return
	* @v: pointer of type atomic_t
	* @i: integer value to subtract
	*
	* Atomically subtracts @i from @v and returns @v - @i
	*/
	static inline int atomic_sub_return(int i, atomic_t *v)
	{
	return atomic_add_return(-i, v);
	}

	static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
	{
	return cmpxchg(&v->counter, old, new);
	}

	static inline int atomic_xchg(atomic_t *v, int new)
	{
	return xchg(&v->counter, new);
	}

	/**
	* atomic_add_unless - add unless the number is already a given value
	* @v: pointer of type atomic_t
	* @a: the amount to add to v...
	* @u: ...unless v is equal to u.
	*
	* Atomically adds @a to @v, so long as @v was not already @u.
	* Returns non-zero if @v was not @u, and zero otherwise.
	*/
	static inline int atomic_add_unless(atomic_t *v, int a, int u)
	{
	int c, old;
	c = atomic_read(v);
	for (;;) {
	if (unlikely(c == (u)))
	break;
	old = atomic_cmpxchg((v), c, c + (a));
	if (likely(old == c))
	break;
	c = old;
	}
	return c != (u);
	}

	#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)

	#define atomic_inc_return(v) (atomic_add_return(1, v))
	#define atomic_dec_return(v) (atomic_sub_return(1, v))

	/* These are x86-specific, used by some header files */
	#define atomic_clear_mask(mask, addr) \
	asm volatile(LOCK_PREFIX "andl %0,%1" \
	: : "r" (~(mask)), "m" (*(addr)) : "memory")

	#define atomic_set_mask(mask, addr) \
	asm volatile(LOCK_PREFIX "orl %0,%1" \
	: : "r" (mask), "m" (*(addr)) : "memory")

	/* Atomic operations are already serializing on x86 */
	#define smp_mb__before_atomic_dec() barrier()
	#define smp_mb__after_atomic_dec() barrier()
	#define smp_mb__before_atomic_inc() barrier()
	#define smp_mb__after_atomic_inc() barrier()

	/* An 64bit atomic type */

	typedef struct {
	u64 __aligned(8) counter;
	} atomic64_t;

	#define ATOMIC64_INIT(val) { (val) }

	extern u64 atomic64_cmpxchg(atomic64_t *ptr, u64 old_val, u64 new_val);

	/**
	* atomic64_xchg - xchg atomic64 variable
	* @ptr: pointer to type atomic64_t
	* @new_val: value to assign
	*
	* Atomically xchgs the value of @ptr to @new_val and returns
	* the old value.
	*/
	extern u64 atomic64_xchg(atomic64_t *ptr, u64 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.
	*/
	extern void atomic64_set(atomic64_t *ptr, u64 new_val);

	/**
	* atomic64_read - read atomic64 variable
	* @ptr: pointer to type atomic64_t
	*
	* Atomically reads the value of @ptr and returns it.
	*/
	static inline u64 atomic64_read(atomic64_t *ptr)
	{
	u64 res;

	/*
	* Note, we inline this atomic64_t primitive because
	* it only clobbers EAX/EDX and leaves the others
	* untouched. We also (somewhat subtly) rely on the
	* fact that cmpxchg8b returns the current 64-bit value
	* of the memory location we are touching:
	*/
	asm volatile(
	"mov %%ebx, %%eax\n\t"
	"mov %%ecx, %%edx\n\t"
	LOCK_PREFIX "cmpxchg8b %1\n"
	: "=&A" (res)
	: "m" (*ptr)
	);

	return res;
	}

	extern u64 atomic64_read(atomic64_t *ptr);

	/**
	* 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
	*/
	extern u64 atomic64_add_return(u64 delta, atomic64_t *ptr);

	/*
	* Other variants with different arithmetic operators:
	*/
	extern u64 atomic64_sub_return(u64 delta, atomic64_t *ptr);
	extern u64 atomic64_inc_return(atomic64_t *ptr);
	extern u64 atomic64_dec_return(atomic64_t *ptr);

	/**
	* atomic64_add - add integer to atomic64 variable
	* @delta: integer value to add
	* @ptr: pointer to type atomic64_t
	*
	* Atomically adds @delta to @ptr.
	*/
	extern void atomic64_add(u64 delta, atomic64_t *ptr);

	/**
	* atomic64_sub - subtract the atomic64 variable
	* @delta: integer value to subtract
	* @ptr: pointer to type atomic64_t
	*
	* Atomically subtracts @delta from @ptr.
	*/
	extern void atomic64_sub(u64 delta, atomic64_t *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.
	*/
	extern int atomic64_sub_and_test(u64 delta, atomic64_t *ptr);

	/**
	* atomic64_inc - increment atomic64 variable
	* @ptr: pointer to type atomic64_t
	*
	* Atomically increments @ptr by 1.
	*/
	extern void atomic64_inc(atomic64_t *ptr);

	/**
	* atomic64_dec - decrement atomic64 variable
	* @ptr: pointer to type atomic64_t
	*
	* Atomically decrements @ptr by 1.
	*/
	extern void atomic64_dec(atomic64_t *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.
	*/
	extern int atomic64_dec_and_test(atomic64_t *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.
	*/
	extern int atomic64_inc_and_test(atomic64_t *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.
	*/
	extern int atomic64_add_negative(u64 delta, atomic64_t *ptr);

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