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-rw-r--r--arch/arm/atomic.h21
1 files changed, 21 insertions, 0 deletions
diff --git a/arch/arm/atomic.h b/arch/arm/atomic.h
index 734d2871..fe88225b 100644
--- a/arch/arm/atomic.h
+++ b/arch/arm/atomic.h
@@ -22,7 +22,28 @@ static inline int a_ctz_64(uint64_t x)
return a_ctz_l(y);
}
+#if __ARM_ARCH_6__ || __ARM_ARCH_6K__ || __ARM_ARCH_6ZK__ \
+ || __ARM_ARCH_7A__ || __ARM_ARCH_7R__ \
+ || __ARM_ARCH >= 7
+static inline int __k_cas(int t, int s, volatile int *p)
+{
+ int ret;
+ __asm__(
+ " mcr p15,0,r0,c7,c10,5\n"
+ "1: ldrex %0,%3\n"
+ " subs %0,%0,%1\n"
+ " strexeq %0,%2,%3\n"
+ " teqeq %0,#1\n"
+ " beq 1b\n"
+ " mcr p15,0,r0,c7,c10,5\n"
+ : "=&r"(ret)
+ : "r"(t), "r"(s), "m"(*p)
+ : "memory", "cc" );
+ return ret;
+}
+#else
#define __k_cas ((int (*)(int, int, volatile int *))0xffff0fc0)
+#endif
static inline int a_cas(volatile int *p, int t, int s)
{