44 lines
802 B
ArmAsm
44 lines
802 B
ArmAsm
/*
|
|
* 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
|