1 files changed, 123 insertions, 0 deletions
diff --git a/arch/loongarch/include/asm/cmpxchg.h b/arch/loongarch/include/asm/cmpxchg.h
new file mode 100644
index 000000000000..75b3a4478652
--- /dev/null
+++ b/arch/loongarch/include/asm/cmpxchg.h
@@ -0,0 +1,123 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#ifndef __ASM_CMPXCHG_H
+#define __ASM_CMPXCHG_H
+
+#include <asm/barrier.h>
+#include <linux/build_bug.h>
+
+#define __xchg_asm(amswap_db, m, val)		\
+({						\
+		__typeof(val) __ret;		\
+						\
+		__asm__ __volatile__ (		\
+		" "amswap_db" %1, %z2, %0 \n"	\
+		: "+ZB" (*m), "=&r" (__ret)	\
+		: "Jr" (val)			\
+		: "memory");			\
+						\
+		__ret;				\
+})
+
+static inline unsigned long __xchg(volatile void *ptr, unsigned long x,
+				   int size)
+{
+	switch (size) {
+	case 4:
+		return __xchg_asm("amswap_db.w", (volatile u32 *)ptr, (u32)x);
+
+	case 8:
+		return __xchg_asm("amswap_db.d", (volatile u64 *)ptr, (u64)x);
+
+	default:
+		BUILD_BUG();
+	}
+
+	return 0;
+}
+
+#define arch_xchg(ptr, x)						\
+({									\
+	__typeof__(*(ptr)) __res;					\
+									\
+	__res = (__typeof__(*(ptr)))					\
+		__xchg((ptr), (unsigned long)(x), sizeof(*(ptr)));	\
+									\
+	__res;								\
+})
+
+#define __cmpxchg_asm(ld, st, m, old, new)				\
+({									\
+	__typeof(old) __ret;						\
+									\
+	__asm__ __volatile__(						\
+	"1:	" ld "	%0, %2		# __cmpxchg_asm \n"		\
+	"	bne	%0, %z3, 2f			\n"		\
+	"	or	$t0, %z4, $zero			\n"		\
+	"	" st "	$t0, %1				\n"		\
+	"	beq	$zero, $t0, 1b			\n"		\
+	"2:						\n"		\
+	__WEAK_LLSC_MB							\
+	: "=&r" (__ret), "=ZB"(*m)					\
+	: "ZB"(*m), "Jr" (old), "Jr" (new)				\
+	: "t0", "memory");						\
+									\
+	__ret;								\
+})
+
+static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
+				      unsigned long new, unsigned int size)
+{
+	switch (size) {
+	case 4:
+		return __cmpxchg_asm("ll.w", "sc.w", (volatile u32 *)ptr,
+				     (u32)old, new);
+
+	case 8:
+		return __cmpxchg_asm("ll.d", "sc.d", (volatile u64 *)ptr,
+				     (u64)old, new);
+
+	default:
+		BUILD_BUG();
+	}
+
+	return 0;
+}
+
+#define arch_cmpxchg_local(ptr, old, new)				\
+	((__typeof__(*(ptr)))						\
+		__cmpxchg((ptr),					\
+			  (unsigned long)(__typeof__(*(ptr)))(old),	\
+			  (unsigned long)(__typeof__(*(ptr)))(new),	\
+			  sizeof(*(ptr))))
+
+#define arch_cmpxchg(ptr, old, new)					\
+({									\
+	__typeof__(*(ptr)) __res;					\
+									\
+	__res = arch_cmpxchg_local((ptr), (old), (new));		\
+									\
+	__res;								\
+})
+
+#ifdef CONFIG_64BIT
+#define arch_cmpxchg64_local(ptr, o, n)					\
+  ({									\
+	BUILD_BUG_ON(sizeof(*(ptr)) != 8);				\
+	arch_cmpxchg_local((ptr), (o), (n));				\
+  })
+
+#define arch_cmpxchg64(ptr, o, n)					\
+  ({									\
+	BUILD_BUG_ON(sizeof(*(ptr)) != 8);				\
+	arch_cmpxchg((ptr), (o), (n));					\
+  })
+#else
+#include <asm-generic/cmpxchg-local.h>
+#define arch_cmpxchg64_local(ptr, o, n) __generic_cmpxchg64_local((ptr), (o), (n))
+#define arch_cmpxchg64(ptr, o, n) arch_cmpxchg64_local((ptr), (o), (n))
+#endif
+
+#endif /* __ASM_CMPXCHG_H */