src/bsp/lk/arch/arm64/spinlock.S

/*
 * Copyright (c) 2014 Google Inc. All rights reserved
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files
 * (the "Software"), to deal in the Software without restriction,
 * including without limitation the rights to use, copy, modify, merge,
 * publish, distribute, sublicense, and/or sell copies of the Software,
 * and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
#include <asm.h>

.text

FUNCTION(arch_spin_trylock)
	mov	x2, x0
	mov	x1, #1
	ldaxr	x0, [x2]
	cbnz	x0, 1f
	stxr	w0, x1, [x2]
1:
	ret

FUNCTION(arch_spin_lock)
	mov	x1, #1
	sevl
1:
	wfe
	ldaxr	x2, [x0]
	cbnz	x2, 1b
	stxr	w2, x1, [x0]
	cbnz	w2, 1b
	ret

FUNCTION(arch_spin_unlock)
	stlr	xzr, [x0]
	ret