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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 01:02:30 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 01:02:30 +0000
commit76cb841cb886eef6b3bee341a2266c76578724ad (patch)
treef5892e5ba6cc11949952a6ce4ecbe6d516d6ce58 /arch/arm/include/asm/mcs_spinlock.h
parentInitial commit. (diff)
downloadlinux-76cb841cb886eef6b3bee341a2266c76578724ad.tar.xz
linux-76cb841cb886eef6b3bee341a2266c76578724ad.zip
Adding upstream version 4.19.249.upstream/4.19.249
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/arm/include/asm/mcs_spinlock.h')
-rw-r--r--arch/arm/include/asm/mcs_spinlock.h24
1 files changed, 24 insertions, 0 deletions
diff --git a/arch/arm/include/asm/mcs_spinlock.h b/arch/arm/include/asm/mcs_spinlock.h
new file mode 100644
index 000000000..529d2cf4d
--- /dev/null
+++ b/arch/arm/include/asm/mcs_spinlock.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ASM_MCS_LOCK_H
+#define __ASM_MCS_LOCK_H
+
+#ifdef CONFIG_SMP
+#include <asm/spinlock.h>
+
+/* MCS spin-locking. */
+#define arch_mcs_spin_lock_contended(lock) \
+do { \
+ /* Ensure prior stores are observed before we enter wfe. */ \
+ smp_mb(); \
+ while (!(smp_load_acquire(lock))) \
+ wfe(); \
+} while (0) \
+
+#define arch_mcs_spin_unlock_contended(lock) \
+do { \
+ smp_store_release(lock, 1); \
+ dsb_sev(); \
+} while (0)
+
+#endif /* CONFIG_SMP */
+#endif /* __ASM_MCS_LOCK_H */