linux/arch/x86/include/asm/local.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_LOCAL_H
#define _ASM_X86_LOCAL_H

#include <linux/percpu.h>

#include <linux/atomic.h>
#include <asm/asm.h>

local_t;

#define LOCAL_INIT(i) …

#define local_read(l) …
#define local_set(l, i) …

static inline void local_inc(local_t *l)
{ … }

static inline void local_dec(local_t *l)
{ … }

static inline void local_add(long i, local_t *l)
{ … }

static inline void local_sub(long i, local_t *l)
{ … }

/**
 * local_sub_and_test - subtract value from variable and test result
 * @i: integer value to subtract
 * @l: pointer to type local_t
 *
 * Atomically subtracts @i from @l and returns
 * true if the result is zero, or false for all
 * other cases.
 */
static inline bool local_sub_and_test(long i, local_t *l)
{ … }

/**
 * local_dec_and_test - decrement and test
 * @l: pointer to type local_t
 *
 * Atomically decrements @l by 1 and
 * returns true if the result is 0, or false for all other
 * cases.
 */
static inline bool local_dec_and_test(local_t *l)
{ … }

/**
 * local_inc_and_test - increment and test
 * @l: pointer to type local_t
 *
 * Atomically increments @l by 1
 * and returns true if the result is zero, or false for all
 * other cases.
 */
static inline bool local_inc_and_test(local_t *l)
{ … }

/**
 * local_add_negative - add and test if negative
 * @i: integer value to add
 * @l: pointer to type local_t
 *
 * Atomically adds @i to @l and returns true
 * if the result is negative, or false when
 * result is greater than or equal to zero.
 */
static inline bool local_add_negative(long i, local_t *l)
{ … }

/**
 * local_add_return - add and return
 * @i: integer value to add
 * @l: pointer to type local_t
 *
 * Atomically adds @i to @l and returns @i + @l
 */
static inline long local_add_return(long i, local_t *l)
{ … }

static inline long local_sub_return(long i, local_t *l)
{ … }

#define local_inc_return(l) …
#define local_dec_return(l) …

static inline long local_cmpxchg(local_t *l, long old, long new)
{ … }

static inline bool local_try_cmpxchg(local_t *l, long *old, long new)
{ … }

/*
 * Implement local_xchg using CMPXCHG instruction without the LOCK prefix.
 * XCHG is expensive due to the implied LOCK prefix.  The processor
 * cannot prefetch cachelines if XCHG is used.
 */
static __always_inline long
local_xchg(local_t *l, long n)
{ … }

/**
 * local_add_unless - add unless the number is already a given value
 * @l: pointer of type local_t
 * @a: the amount to add to l...
 * @u: ...unless l is equal to u.
 *
 * Atomically adds @a to @l, if @v was not already @u.
 * Returns true if the addition was done.
 */
static __always_inline bool
local_add_unless(local_t *l, long a, long u)
{ … }

#define local_inc_not_zero(l) …

/* On x86_32, these are no better than the atomic variants.
 * On x86-64 these are better than the atomic variants on SMP kernels
 * because they dont use a lock prefix.
 */
#define __local_inc(l) …
#define __local_dec(l) …
#define __local_add(i, l) …
#define __local_sub(i, l) …

#endif /* _ASM_X86_LOCAL_H */