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

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
 */
#ifndef _ARCH_LOONGARCH_LOCAL_H
#define _ARCH_LOONGARCH_LOCAL_H

#include <linux/percpu.h>
#include <linux/bitops.h>
#include <linux/atomic.h>
#include <asm/asm.h>
#include <asm/cmpxchg.h>

typedef struct {
	atomic_long_t a;
} local_t;

#define LOCAL_INIT(i)	{ ATOMIC_LONG_INIT(i) }

#define local_read(l)	atomic_long_read(&(l)->a)
#define local_set(l, i) atomic_long_set(&(l)->a, (i))

#define local_add(i, l) atomic_long_add((i), (&(l)->a))
#define local_sub(i, l) atomic_long_sub((i), (&(l)->a))
#define local_inc(l)	atomic_long_inc(&(l)->a)
#define local_dec(l)	atomic_long_dec(&(l)->a)

/*
 * Same as above, but return the result value
 */
#ifdef CONFIG_CPU_HAS_AMO
static inline long local_add_return(long i, local_t *l)
{
	unsigned long result;

	__asm__ __volatile__(
	"   " __AMADD " %1, %2, %0      \n"
	: "+ZB" (l->a.counter), "=&r" (result)
	: "r" (i)
	: "memory");
	result = result + i;

	return result;
}

static inline long local_sub_return(long i, local_t *l)
{
	unsigned long result;

	__asm__ __volatile__(
	"   " __AMADD "%1, %2, %0       \n"
	: "+ZB" (l->a.counter), "=&r" (result)
	: "r" (-i)
	: "memory");

	result = result - i;

	return result;
}
#else
static inline long local_add_return(long i, local_t *l)
{
        unsigned long result, temp;

        __asm__ __volatile__(
        "1:"    __LL    "%1, %2         # local_add_return      \n"
        __stringify(LONG_ADD) "   %0, %1, %3                    \n"
                __SC    "%0, %2                                 \n"
        "       beq     %0, $r0, 1b                             \n"
        __stringify(LONG_ADD) "   %0, %1, %3                    \n"
        : "=&r" (result), "=&r" (temp), "=ZC" (l->a.counter)
        : "r" (i), "ZC" (l->a.counter)
        : "memory");

        return result;
}

static inline long local_sub_return(long i, local_t *l)
{
        unsigned long result, temp;

        __asm__ __volatile__(
        "1:"    __LL    "%1, %2         # local_sub_return      \n"
        __stringify(LONG_SUB) "   %0, %1, %3                    \n"
                __SC    "%0, %2                                 \n"
        "       beq     %0, $r0, 1b                             \n"
	__stringify(LONG_SUB) "   %0, %1, %3                    \n"
        : "=&r" (result), "=&r" (temp), "=ZC" (l->a.counter)
        : "r" (i), "ZC" (l->a.counter)
        : "memory");

        return result;
}
#endif

static inline long local_cmpxchg(local_t *l, long old, long new)
{
	return cmpxchg_local(&l->a.counter, old, new);
}

static inline bool local_try_cmpxchg(local_t *l, long *old, long new)
{
	return try_cmpxchg_local(&l->a.counter,
				 (typeof(l->a.counter) *) old, new);
}

#define local_xchg(l, n) (atomic_long_xchg((&(l)->a), (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 inline bool
local_add_unless(local_t *l, long a, long u)
{
	long c = local_read(l);

	do {
		if (unlikely(c == u))
			return false;
	} while (!local_try_cmpxchg(l, &c, c + a));

	return true;
}

#define local_inc_not_zero(l) local_add_unless((l), 1, 0)

#define local_dec_return(l) local_sub_return(1, (l))
#define local_inc_return(l) local_add_return(1, (l))

/*
 * local_sub_and_test - subtract value from variable and test result
 * @i: integer value to subtract
 * @l: pointer of type local_t
 *
 * Atomically subtracts @i from @l and returns
 * true if the result is zero, or false for all
 * other cases.
 */
#define local_sub_and_test(i, l) (local_sub_return((i), (l)) == 0)

/*
 * local_inc_and_test - increment and test
 * @l: pointer of type local_t
 *
 * Atomically increments @l by 1
 * and returns true if the result is zero, or false for all
 * other cases.
 */
#define local_inc_and_test(l) (local_inc_return(l) == 0)

/*
 * local_dec_and_test - decrement by 1 and test
 * @l: pointer of type local_t
 *
 * Atomically decrements @l by 1 and
 * returns true if the result is 0, or false for all other
 * cases.
 */
#define local_dec_and_test(l) (local_sub_return(1, (l)) == 0)

/*
 * local_add_negative - add and test if negative
 * @l: pointer of type local_t
 * @i: integer value to add
 *
 * Atomically adds @i to @l and returns true
 * if the result is negative, or false when
 * result is greater than or equal to zero.
 */
#define local_add_negative(i, l) (local_add_return(i, (l)) < 0)

/* Use these for per-cpu local_t variables: on some archs they are
 * much more efficient than these naive implementations.  Note they take
 * a variable, not an address.
 */

#define __local_inc(l)		((l)->a.counter++)
#define __local_dec(l)		((l)->a.counter++)
#define __local_add(i, l)	((l)->a.counter += (i))
#define __local_sub(i, l)	((l)->a.counter -= (i))

#endif /* _ARCH_LOONGARCH_LOCAL_H */