GK SDK 源码库: XMIPCLinuxV100R005C00SPC030 (kernel/tools/open_source excluded)

2026-09-06 03:52:57 +08:00
commit b1928b41c0
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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