From f9cc3cd9b4de58cf032c8624406384c172937e57 Mon Sep 17 00:00:00 2001 From: David Vrabel Date: Fri, 8 May 2015 10:59:44 +0200 Subject: [PATCH] arm: provide arch_fetch_and_add() arch_fetch_and_add() atomically adds a value and returns the previous value. This generic arm implementation uses the GCC __sync_fetch_and_add() builtin. This builtin resulted in suitable inlined asm for GCC 4.8.3 (arm64) and GCC 4.6.3 (arm32). This is needed to implement ticket locks. Signed-off-by: David Vrabel Acked-by: Ian Campbell --- xen/include/asm-arm/system.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/xen/include/asm-arm/system.h b/xen/include/asm-arm/system.h index ce3d38ac0c..2eb96e8769 100644 --- a/xen/include/asm-arm/system.h +++ b/xen/include/asm-arm/system.h @@ -51,6 +51,8 @@ # error "unknown ARM variant" #endif +#define arch_fetch_and_add(x, v) __sync_fetch_and_add(x, v) + extern struct vcpu *__context_switch(struct vcpu *prev, struct vcpu *next); #endif -- 2.30.2