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