1 files changed, 100 insertions, 0 deletions
diff --git a/arch/loongarch/include/asm/atomic-llsc.h b/arch/loongarch/include/asm/atomic-llsc.h
new file mode 100644
index 000000000000..3ce500c88272
--- /dev/null
+++ b/arch/loongarch/include/asm/atomic-llsc.h
@@ -0,0 +1,100 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Atomic operations (LLSC).
+ *
+ * Copyright (C) 2024-2025 Loongson Technology Corporation Limited
+ */
+
+#ifndef _ASM_ATOMIC_LLSC_H
+#define _ASM_ATOMIC_LLSC_H
+
+#include <linux/types.h>
+#include <asm/barrier.h>
+#include <asm/cmpxchg.h>
+
+#define ATOMIC_OP(op, I, asm_op)					\
+static inline void arch_atomic_##op(int i, atomic_t *v)			\
+{									\
+	int temp;							\
+									\
+	__asm__ __volatile__(						\
+	"1:	ll.w		%0, %1      #atomic_" #op "	\n"	\
+	"       " #asm_op "	%0, %0, %2			\n"	\
+	"	sc.w		%0, %1				\n"	\
+	"       beq		%0, $r0, 1b			\n"	\
+	:"=&r" (temp) , "+ZC"(v->counter)				\
+	:"r" (I)							\
+	);								\
+}
+
+#define ATOMIC_OP_RETURN(op, I, asm_op)					\
+static inline int arch_atomic_##op##_return_relaxed(int i, atomic_t *v)	\
+{									\
+	int result, temp;						\
+									\
+	__asm__ __volatile__(						\
+	"1:     ll.w		%1, %2      # atomic_" #op "_return \n"	\
+	"       " #asm_op "	%0, %1, %3                          \n"	\
+	"       sc.w		%0, %2                              \n"	\
+	"       beq		%0, $r0 ,1b                         \n"	\
+	"       " #asm_op "	%0, %1, %3                          \n"	\
+	: "=&r" (result), "=&r" (temp),	"+ZC"(v->counter)		\
+	: "r" (I));							\
+									\
+	return result;							\
+}
+
+#define ATOMIC_FETCH_OP(op, I, asm_op)					\
+static inline int arch_atomic_fetch_##op##_relaxed(int i, atomic_t *v)	\
+{									\
+	int result, temp;						\
+									\
+	__asm__ __volatile__(						\
+	"1:     ll.w		%1, %2      # atomic_fetch_" #op "  \n"	\
+	"       " #asm_op "	%0, %1, %3                          \n" \
+	"       sc.w		%0, %2                              \n"	\
+	"       beq		%0, $r0 ,1b                         \n"	\
+	"       add.w		%0, %1  ,$r0                        \n"	\
+	: "=&r" (result), "=&r" (temp), "+ZC" (v->counter)		\
+	: "r" (I));							\
+									\
+	return result;							\
+}
+
+#define ATOMIC_OPS(op,I ,asm_op, c_op)					\
+	ATOMIC_OP(op, I, asm_op)					\
+	ATOMIC_OP_RETURN(op, I , asm_op)				\
+	ATOMIC_FETCH_OP(op, I, asm_op)
+
+ATOMIC_OPS(add, i , add.w ,+=)
+ATOMIC_OPS(sub, -i , add.w ,+=)
+
+#define arch_atomic_add_return_relaxed	arch_atomic_add_return_relaxed
+#define arch_atomic_sub_return_relaxed	arch_atomic_sub_return_relaxed
+#define arch_atomic_fetch_add_relaxed	arch_atomic_fetch_add_relaxed
+#define arch_atomic_fetch_sub_relaxed	arch_atomic_fetch_sub_relaxed
+
+#undef ATOMIC_OPS
+
+#define ATOMIC_OPS(op, I, asm_op)					\
+	ATOMIC_OP(op, I, asm_op)					\
+	ATOMIC_FETCH_OP(op, I, asm_op)
+
+ATOMIC_OPS(and, i, and)
+ATOMIC_OPS(or, i, or)
+ATOMIC_OPS(xor, i, xor)
+
+#define arch_atomic_fetch_and_relaxed	arch_atomic_fetch_and_relaxed
+#define arch_atomic_fetch_or_relaxed	arch_atomic_fetch_or_relaxed
+#define arch_atomic_fetch_xor_relaxed	arch_atomic_fetch_xor_relaxed
+
+#undef ATOMIC_OPS
+#undef ATOMIC_FETCH_OP
+#undef ATOMIC_OP_RETURN
+#undef ATOMIC_OP
+
+#ifdef CONFIG_64BIT
+#error "64-bit LLSC atomic operations are not supported"
+#endif
+
+#endif /* _ASM_ATOMIC_LLSC_H */