[PATCH 7/9] arm64: Add atomic macros to assembler.h
From: geoff@infradead.org (Geoff Levand)
Date: 2014-08-22 19:49:16
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
Add an assembler macro definition 'atomic' for performing generic atomic operations. Also add macro definitions for atomic_add, atomic_sub, atomic_inc, and atomic_dec. Signed-off-by: Geoff Levand <geoff@infradead.org> --- arch/arm64/include/asm/assembler.h | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+)
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index 5901480..dad3118 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h@@ -23,6 +23,39 @@ #include <asm/ptrace.h> #include <asm/thread_info.h> +/** + * macro atomic - Macros for simple atomic operations. + * + * @op: The operation to perform. + * @reg: A 32 or 64 bit register to operate on. + * @value: The value for the operation. + * @tmp1: A scratch register the same size as @reg. Defaluts to x20. + * @tmp2: A 32 bit scratch register. Defaluts to w21. + **/ + + .macro atomic op:req, reg:req, value:req, tmp1=x20, tmp2=w21 +.Latomic\@: ldxr \tmp1, [\reg] + \op \tmp1, \tmp1, \value + stxr \tmp2, \tmp1, [\reg] + cbnz \tmp2, .Latomic\@ + .endm + + .macro atomic_add reg:req, value:req, tmp1=x20, tmp2=w21 + atomic add, \reg, \value, \tmp1, \tmp2 + .endm + + .macro atomic_sub reg:req, value:req, tmp1, tmp2 + atomic sub, \reg, \value, \tmp1, \tmp2 + .endm + + .macro atomic_inc reg:req, tmp1, tmp2 + atomic add, \reg, 1, \tmp1, \tmp2 + .endm + + .macro atomic_dec reg:req, tmp1, tmp2 + atomic sub, \reg, 1, \tmp1, \tmp2 + .endm + /* * Stack pushing/popping (register pairs only). Equivalent to store decrement * before, load increment after.
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1.9.1