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/*
* Copyright (c) 2016, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <asm_macros.S>
.globl spin_lock
.globl spin_unlock
#if ARM_ARCH_AT_LEAST(8, 0)
/*
* According to the ARMv8-A Architecture Reference Manual, "when the global
* monitor for a PE changes from Exclusive Access state to Open Access state,
* an event is generated.". This applies to both AArch32 and AArch64 modes of
* ARMv8-A. As a result, no explicit SEV with unlock is required.
*/
#define COND_SEV()
#else
#define COND_SEV() sev
#endif
func spin_lock
mov r2, #1
1:
ldrex r1, [r0]
cmp r1, #0
wfene
strexeq r1, r2, [r0]
cmpeq r1, #0
bne 1b
dmb
bx lr
endfunc spin_lock
func spin_unlock
mov r1, #0
stl r1, [r0]
COND_SEV()
bx lr
endfunc spin_unlock
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