v4.19.13 snapshot.
diff --git a/arch/parisc/include/asm/futex.h b/arch/parisc/include/asm/futex.h
new file mode 100644
index 0000000..cf7ba05
--- /dev/null
+++ b/arch/parisc/include/asm/futex.h
@@ -0,0 +1,125 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_PARISC_FUTEX_H
+#define _ASM_PARISC_FUTEX_H
+
+#ifdef __KERNEL__
+
+#include <linux/futex.h>
+#include <linux/uaccess.h>
+#include <asm/atomic.h>
+#include <asm/errno.h>
+
+/* The following has to match the LWS code in syscall.S. We have
+ sixteen four-word locks. */
+
+static inline void
+_futex_spin_lock_irqsave(u32 __user *uaddr, unsigned long int *flags)
+{
+ extern u32 lws_lock_start[];
+ long index = ((long)uaddr & 0xf0) >> 2;
+ arch_spinlock_t *s = (arch_spinlock_t *)&lws_lock_start[index];
+ local_irq_save(*flags);
+ arch_spin_lock(s);
+}
+
+static inline void
+_futex_spin_unlock_irqrestore(u32 __user *uaddr, unsigned long int *flags)
+{
+ extern u32 lws_lock_start[];
+ long index = ((long)uaddr & 0xf0) >> 2;
+ arch_spinlock_t *s = (arch_spinlock_t *)&lws_lock_start[index];
+ arch_spin_unlock(s);
+ local_irq_restore(*flags);
+}
+
+static inline int
+arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
+{
+ unsigned long int flags;
+ int oldval, ret;
+ u32 tmp;
+
+ _futex_spin_lock_irqsave(uaddr, &flags);
+ pagefault_disable();
+
+ ret = -EFAULT;
+ if (unlikely(get_user(oldval, uaddr) != 0))
+ goto out_pagefault_enable;
+
+ ret = 0;
+ tmp = oldval;
+
+ switch (op) {
+ case FUTEX_OP_SET:
+ tmp = oparg;
+ break;
+ case FUTEX_OP_ADD:
+ tmp += oparg;
+ break;
+ case FUTEX_OP_OR:
+ tmp |= oparg;
+ break;
+ case FUTEX_OP_ANDN:
+ tmp &= ~oparg;
+ break;
+ case FUTEX_OP_XOR:
+ tmp ^= oparg;
+ break;
+ default:
+ ret = -ENOSYS;
+ }
+
+ if (ret == 0 && unlikely(put_user(tmp, uaddr) != 0))
+ ret = -EFAULT;
+
+out_pagefault_enable:
+ pagefault_enable();
+ _futex_spin_unlock_irqrestore(uaddr, &flags);
+
+ if (!ret)
+ *oval = oldval;
+
+ return ret;
+}
+
+static inline int
+futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
+ u32 oldval, u32 newval)
+{
+ u32 val;
+ unsigned long flags;
+
+ /* futex.c wants to do a cmpxchg_inatomic on kernel NULL, which is
+ * our gateway page, and causes no end of trouble...
+ */
+ if (uaccess_kernel() && !uaddr)
+ return -EFAULT;
+
+ if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
+ return -EFAULT;
+
+ /* HPPA has no cmpxchg in hardware and therefore the
+ * best we can do here is use an array of locks. The
+ * lock selected is based on a hash of the userspace
+ * address. This should scale to a couple of CPUs.
+ */
+
+ _futex_spin_lock_irqsave(uaddr, &flags);
+ if (unlikely(get_user(val, uaddr) != 0)) {
+ _futex_spin_unlock_irqrestore(uaddr, &flags);
+ return -EFAULT;
+ }
+
+ if (val == oldval && unlikely(put_user(newval, uaddr) != 0)) {
+ _futex_spin_unlock_irqrestore(uaddr, &flags);
+ return -EFAULT;
+ }
+
+ *uval = val;
+ _futex_spin_unlock_irqrestore(uaddr, &flags);
+
+ return 0;
+}
+
+#endif /*__KERNEL__*/
+#endif /*_ASM_PARISC_FUTEX_H*/