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authorVincenzo Frascino <vincenzo.frascino@arm.com>2020-03-20 14:53:44 +0000
committerThomas Gleixner <tglx@linutronix.de>2020-03-21 15:24:01 +0100
commitf511e079177a9b97175a9a3b0ee2374d55682403 (patch)
tree37036a0586949ed054d03cbd462177eb2928e248 /arch/arm64/include/asm/vdso
parent94d0f5be885ce1e6ca2886af1543165c16745d13 (diff)
arm64: Introduce asm/vdso/processor.h
The vDSO library should only include the necessary headers required for a userspace library (UAPI and a minimal set of kernel headers). To make this possible it is necessary to isolate from the kernel headers the common parts that are strictly necessary to build the library. Introduce asm/vdso/processor.h to contain all the arm64 specific functions that are suitable for vDSO inclusion. Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Link: https://lkml.kernel.org/r/20200320145351.32292-20-vincenzo.frascino@arm.com
Diffstat (limited to 'arch/arm64/include/asm/vdso')
-rw-r--r--arch/arm64/include/asm/vdso/processor.h17
1 files changed, 17 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/vdso/processor.h b/arch/arm64/include/asm/vdso/processor.h
new file mode 100644
index 000000000000..ff830b766ad2
--- /dev/null
+++ b/arch/arm64/include/asm/vdso/processor.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2020 ARM Ltd.
+ */
+#ifndef __ASM_VDSO_PROCESSOR_H
+#define __ASM_VDSO_PROCESSOR_H
+
+#ifndef __ASSEMBLY__
+
+static inline void cpu_relax(void)
+{
+ asm volatile("yield" ::: "memory");
+}
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* __ASM_VDSO_PROCESSOR_H */