v4.19.13 snapshot.
diff --git a/arch/s390/include/asm/futex.h b/arch/s390/include/asm/futex.h
new file mode 100644
index 0000000..5e97a43
--- /dev/null
+++ b/arch/s390/include/asm/futex.h
@@ -0,0 +1,87 @@
+/* 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(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();
+ pagefault_disable();
+ 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;
+ }
+ pagefault_enable();
+ 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 */