1 files changed, 124 insertions, 0 deletions
diff --git a/arch/mips/include/asm/cmpxchg.h b/arch/mips/include/asm/cmpxchg.h
index d8d1c2805ac7..285a41fa0b18 100644
--- a/arch/mips/include/asm/cmpxchg.h
+++ b/arch/mips/include/asm/cmpxchg.h
@@ -9,6 +9,130 @@
 #define __ASM_CMPXCHG_H
 
 #include <linux/irqflags.h>
+#include <asm/war.h>
+
+static inline unsigned long __xchg_u32(volatile int * m, unsigned int val)
+{
+	__u32 retval;
+
+	smp_mb__before_llsc();
+
+	if (kernel_uses_llsc && R10000_LLSC_WAR) {
+		unsigned long dummy;
+
+		__asm__ __volatile__(
+		"	.set	mips3					\n"
+		"1:	ll	%0, %3			# xchg_u32	\n"
+		"	.set	mips0					\n"
+		"	move	%2, %z4					\n"
+		"	.set	mips3					\n"
+		"	sc	%2, %1					\n"
+		"	beqzl	%2, 1b					\n"
+		"	.set	mips0					\n"
+		: "=&r" (retval), "=m" (*m), "=&r" (dummy)
+		: "R" (*m), "Jr" (val)
+		: "memory");
+	} else if (kernel_uses_llsc) {
+		unsigned long dummy;
+
+		do {
+			__asm__ __volatile__(
+			"	.set	mips3				\n"
+			"	ll	%0, %3		# xchg_u32	\n"
+			"	.set	mips0				\n"
+			"	move	%2, %z4				\n"
+			"	.set	mips3				\n"
+			"	sc	%2, %1				\n"
+			"	.set	mips0				\n"
+			: "=&r" (retval), "=m" (*m), "=&r" (dummy)
+			: "R" (*m), "Jr" (val)
+			: "memory");
+		} while (unlikely(!dummy));
+	} else {
+		unsigned long flags;
+
+		raw_local_irq_save(flags);
+		retval = *m;
+		*m = val;
+		raw_local_irq_restore(flags);	/* implies memory barrier  */
+	}
+
+	smp_llsc_mb();
+
+	return retval;
+}
+
+#ifdef CONFIG_64BIT
+static inline __u64 __xchg_u64(volatile __u64 * m, __u64 val)
+{
+	__u64 retval;
+
+	smp_mb__before_llsc();
+
+	if (kernel_uses_llsc && R10000_LLSC_WAR) {
+		unsigned long dummy;
+
+		__asm__ __volatile__(
+		"	.set	mips3					\n"
+		"1:	lld	%0, %3			# xchg_u64	\n"
+		"	move	%2, %z4					\n"
+		"	scd	%2, %1					\n"
+		"	beqzl	%2, 1b					\n"
+		"	.set	mips0					\n"
+		: "=&r" (retval), "=m" (*m), "=&r" (dummy)
+		: "R" (*m), "Jr" (val)
+		: "memory");
+	} else if (kernel_uses_llsc) {
+		unsigned long dummy;
+
+		do {
+			__asm__ __volatile__(
+			"	.set	mips3				\n"
+			"	lld	%0, %3		# xchg_u64	\n"
+			"	move	%2, %z4				\n"
+			"	scd	%2, %1				\n"
+			"	.set	mips0				\n"
+			: "=&r" (retval), "=m" (*m), "=&r" (dummy)
+			: "R" (*m), "Jr" (val)
+			: "memory");
+		} while (unlikely(!dummy));
+	} else {
+		unsigned long flags;
+
+		raw_local_irq_save(flags);
+		retval = *m;
+		*m = val;
+		raw_local_irq_restore(flags);	/* implies memory barrier  */
+	}
+
+	smp_llsc_mb();
+
+	return retval;
+}
+#else
+extern __u64 __xchg_u64_unsupported_on_32bit_kernels(volatile __u64 * m, __u64 val);
+#define __xchg_u64 __xchg_u64_unsupported_on_32bit_kernels
+#endif
+
+static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size)
+{
+	switch (size) {
+	case 4:
+		return __xchg_u32(ptr, x);
+	case 8:
+		return __xchg_u64(ptr, x);
+	}
+
+	return x;
+}
+
+#define xchg(ptr, x)							\
+({									\
+	BUILD_BUG_ON(sizeof(*(ptr)) & ~0xc);				\
+									\
+	((__typeof__(*(ptr)))						\
+		__xchg((unsigned long)(x), (ptr), sizeof(*(ptr))));	\
+})
 
 #define __HAVE_ARCH_CMPXCHG 1