blob: c9ce489d3904a2ca0babbff6a0b880aadb58fe09 [file] [log] [blame]
#ifndef __ATOMIC_H
#define __ATOMIC_H
#include "asm-generic/atomic.h"
typedef struct {
volatile int counter;
} atomic_t;
#ifdef __i386__
/**
* 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_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 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 decl %0"
: "+m" (v->counter));
}
typedef struct {
u64 __attribute__((aligned(8))) counter;
} atomic64_t;
#define ATOMIC64_INIT(val) { (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 cmpxchg8b %1\n"
: "=&A" (res)
: "m" (*ptr)
);
return res;
}
u64 atomic64_cmpxchg(atomic64_t *v, u64 old, u64 new);
#elif defined(__x86_64__)
/**
* 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_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 incl %0"
: "=m" (v->counter)
: "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 decl %0"
: "=m" (v->counter)
: "m" (v->counter));
}
typedef struct {
long long counter;
} atomic64_t;
#define ATOMIC64_INIT(i) { (i) }
/**
* atomic64_read - read atomic64 variable
* @v: pointer of type atomic64_t
*
* Atomically reads the value of @v.
* Doesn't imply a read memory barrier.
*/
static inline long atomic64_read(const atomic64_t *v)
{
return v->counter;
}
u64 atomic64_cmpxchg(atomic64_t *v, u64 old, u64 new);
#endif
#endif