1 files changed, 86 insertions, 0 deletions
diff --git a/arch/s390/include/asm/futex.h b/arch/s390/include/asm/futex.h
new file mode 100644
index 000000000..e1d0b2aaa
--- /dev/null
+++ b/arch/s390/include/asm/futex.h
@@ -0,0 +1,86 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_S390_FUTEX_H
+#define _ASM_S390_FUTEX_H
+
+#include <linux/uaccess.h>
+#include <linux/futex.h>
+#include <asm/mmu_context.h>
+#include <asm/errno.h>
+
+#define __futex_atomic_op(insn, ret, oldval, newval, uaddr, oparg)	\
+	asm volatile(							\
+		"   sacf  256\n"					\
+		"0: l     %1,0(%6)\n"					\
+		"1:"insn						\
+		"2: cs    %1,%2,0(%6)\n"				\
+		"3: jl    1b\n"						\
+		"   lhi   %0,0\n"					\
+		"4: sacf  768\n"					\
+		EX_TABLE(0b,4b) EX_TABLE(1b,4b)				\
+		EX_TABLE(2b,4b) EX_TABLE(3b,4b)				\
+		: "=d" (ret), "=&d" (oldval), "=&d" (newval),		\
+		  "=m" (*uaddr)						\
+		: "0" (-EFAULT), "d" (oparg), "a" (uaddr),		\
+		  "m" (*uaddr) : "cc");
+
+static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
+		u32 __user *uaddr)
+{
+	int oldval = 0, newval, ret;
+	mm_segment_t old_fs;
+
+	old_fs = enable_sacf_uaccess();
+	switch (op) {
+	case FUTEX_OP_SET:
+		__futex_atomic_op("lr %2,%5\n",
+				  ret, oldval, newval, uaddr, oparg);
+		break;
+	case FUTEX_OP_ADD:
+		__futex_atomic_op("lr %2,%1\nar %2,%5\n",
+				  ret, oldval, newval, uaddr, oparg);
+		break;
+	case FUTEX_OP_OR:
+		__futex_atomic_op("lr %2,%1\nor %2,%5\n",
+				  ret, oldval, newval, uaddr, oparg);
+		break;
+	case FUTEX_OP_ANDN:
+		__futex_atomic_op("lr %2,%1\nnr %2,%5\n",
+				  ret, oldval, newval, uaddr, oparg);
+		break;
+	case FUTEX_OP_XOR:
+		__futex_atomic_op("lr %2,%1\nxr %2,%5\n",
+				  ret, oldval, newval, uaddr, oparg);
+		break;
+	default:
+		ret = -ENOSYS;
+	}
+	disable_sacf_uaccess(old_fs);
+
+	if (!ret)
+		*oval = oldval;
+
+	return ret;
+}
+
+static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
+						u32 oldval, u32 newval)
+{
+	mm_segment_t old_fs;
+	int ret;
+
+	old_fs = enable_sacf_uaccess();
+	asm volatile(
+		"   sacf 256\n"
+		"0: cs   %1,%4,0(%5)\n"
+		"1: la   %0,0\n"
+		"2: sacf 768\n"
+		EX_TABLE(0b,2b) EX_TABLE(1b,2b)
+		: "=d" (ret), "+d" (oldval), "=m" (*uaddr)
+		: "0" (-EFAULT), "d" (newval), "a" (uaddr), "m" (*uaddr)
+		: "cc", "memory");
+	disable_sacf_uaccess(old_fs);
+	*uval = oldval;
+	return ret;
+}
+
+#endif /* _ASM_S390_FUTEX_H */