1 files changed, 95 insertions, 0 deletions
diff --git a/arch/alpha/include/asm/futex.h b/arch/alpha/include/asm/futex.h
new file mode 100644
index 000000000..da67afd57
--- /dev/null
+++ b/arch/alpha/include/asm/futex.h
@@ -0,0 +1,95 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_ALPHA_FUTEX_H
+#define _ASM_ALPHA_FUTEX_H
+
+#ifdef __KERNEL__
+
+#include <linux/futex.h>
+#include <linux/uaccess.h>
+#include <asm/errno.h>
+#include <asm/barrier.h>
+
+#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)	\
+	__asm__ __volatile__(					\
+		__ASM_SMP_MB					\
+	"1:	ldl_l	%0,0(%2)\n"				\
+		insn						\
+	"2:	stl_c	%1,0(%2)\n"				\
+	"	beq	%1,4f\n"				\
+	"	mov	$31,%1\n"				\
+	"3:	.subsection 2\n"				\
+	"4:	br	1b\n"					\
+	"	.previous\n"					\
+	EXC(1b,3b,$31,%1)					\
+	EXC(2b,3b,$31,%1)					\
+	:	"=&r" (oldval), "=&r"(ret)			\
+	:	"r" (uaddr), "r"(oparg)				\
+	:	"memory")
+
+static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
+		u32 __user *uaddr)
+{
+	int oldval = 0, ret;
+
+	if (!access_ok(uaddr, sizeof(u32)))
+		return -EFAULT;
+
+	switch (op) {
+	case FUTEX_OP_SET:
+		__futex_atomic_op("mov %3,%1\n", ret, oldval, uaddr, oparg);
+		break;
+	case FUTEX_OP_ADD:
+		__futex_atomic_op("addl %0,%3,%1\n", ret, oldval, uaddr, oparg);
+		break;
+	case FUTEX_OP_OR:
+		__futex_atomic_op("or %0,%3,%1\n", ret, oldval, uaddr, oparg);
+		break;
+	case FUTEX_OP_ANDN:
+		__futex_atomic_op("andnot %0,%3,%1\n", ret, oldval, uaddr, oparg);
+		break;
+	case FUTEX_OP_XOR:
+		__futex_atomic_op("xor %0,%3,%1\n", ret, oldval, uaddr, oparg);
+		break;
+	default:
+		ret = -ENOSYS;
+	}
+
+	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, cmp;
+	u32 prev;
+
+	if (!access_ok(uaddr, sizeof(u32)))
+		return -EFAULT;
+
+	__asm__ __volatile__ (
+		__ASM_SMP_MB
+	"1:	ldl_l	%1,0(%3)\n"
+	"	cmpeq	%1,%4,%2\n"
+	"	beq	%2,3f\n"
+	"	mov	%5,%2\n"
+	"2:	stl_c	%2,0(%3)\n"
+	"	beq	%2,4f\n"
+	"3:	.subsection 2\n"
+	"4:	br	1b\n"
+	"	.previous\n"
+	EXC(1b,3b,$31,%0)
+	EXC(2b,3b,$31,%0)
+	:	"+r"(ret), "=&r"(prev), "=&r"(cmp)
+	:	"r"(uaddr), "r"((long)(int)oldval), "r"(newval)
+	:	"memory");
+
+	*uval = prev;
+	return ret;
+}
+
+#endif /* __KERNEL__ */
+#endif /* _ASM_ALPHA_FUTEX_H */