1 files changed, 107 insertions, 0 deletions
diff --git a/arch/loongarch/include/asm/futex.h b/arch/loongarch/include/asm/futex.h
new file mode 100644
index 000000000000..feb6658c84ff
--- /dev/null
+++ b/arch/loongarch/include/asm/futex.h
@@ -0,0 +1,107 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#ifndef _ASM_FUTEX_H
+#define _ASM_FUTEX_H
+
+#include <linux/futex.h>
+#include <linux/uaccess.h>
+#include <asm/barrier.h>
+#include <asm/errno.h>
+
+#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)		\
+{									\
+	__asm__ __volatile__(						\
+	"1:	ll.w	%1, %4 # __futex_atomic_op\n"		\
+	"	" insn	"				\n"	\
+	"2:	sc.w	$t0, %2				\n"	\
+	"	beqz	$t0, 1b				\n"	\
+	"3:						\n"	\
+	"	.section .fixup,\"ax\"			\n"	\
+	"4:	li.w	%0, %6				\n"	\
+	"	b	3b				\n"	\
+	"	.previous				\n"	\
+	"	.section __ex_table,\"a\"		\n"	\
+	"	"__UA_ADDR "\t1b, 4b			\n"	\
+	"	"__UA_ADDR "\t2b, 4b			\n"	\
+	"	.previous				\n"	\
+	: "=r" (ret), "=&r" (oldval),				\
+	  "=ZC" (*uaddr)					\
+	: "0" (0), "ZC" (*uaddr), "Jr" (oparg),			\
+	  "i" (-EFAULT)						\
+	: "memory", "t0");					\
+}
+
+static inline int
+arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
+{
+	int oldval = 0, ret = 0;
+
+	pagefault_disable();
+
+	switch (op) {
+	case FUTEX_OP_SET:
+		__futex_atomic_op("move $t0, %z5", ret, oldval, uaddr, oparg);
+		break;
+	case FUTEX_OP_ADD:
+		__futex_atomic_op("add.w $t0, %1, %z5", ret, oldval, uaddr, oparg);
+		break;
+	case FUTEX_OP_OR:
+		__futex_atomic_op("or	$t0, %1, %z5", ret, oldval, uaddr, oparg);
+		break;
+	case FUTEX_OP_ANDN:
+		__futex_atomic_op("and	$t0, %1, %z5", ret, oldval, uaddr, ~oparg);
+		break;
+	case FUTEX_OP_XOR:
+		__futex_atomic_op("xor	$t0, %1, %z5", ret, oldval, uaddr, oparg);
+		break;
+	default:
+		ret = -ENOSYS;
+	}
+
+	pagefault_enable();
+
+	if (!ret)
+		*oval = oldval;
+
+	return ret;
+}
+
+static inline int
+futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval, u32 newval)
+{
+	int ret = 0;
+	u32 val = 0;
+
+	if (!access_ok(uaddr, sizeof(u32)))
+		return -EFAULT;
+
+	__asm__ __volatile__(
+	"# futex_atomic_cmpxchg_inatomic			\n"
+	"1:	ll.w	%1, %3					\n"
+	"	bne	%1, %z4, 3f				\n"
+	"	move	$t0, %z5				\n"
+	"2:	sc.w	$t0, %2					\n"
+	"	beqz	$t0, 1b					\n"
+	"3:							\n"
+	__WEAK_LLSC_MB
+	"	.section .fixup,\"ax\"				\n"
+	"4:	li.d	%0, %6					\n"
+	"	b	3b					\n"
+	"	.previous					\n"
+	"	.section __ex_table,\"a\"			\n"
+	"	"__UA_ADDR "\t1b, 4b				\n"
+	"	"__UA_ADDR "\t2b, 4b				\n"
+	"	.previous					\n"
+	: "+r" (ret), "=&r" (val), "=ZC" (*uaddr)
+	: "ZC" (*uaddr), "Jr" (oldval), "Jr" (newval),
+	  "i" (-EFAULT)
+	: "memory", "t0");
+
+	*uval = val;
+
+	return ret;
+}
+
+#endif /* _ASM_FUTEX_H */