1 files changed, 41 insertions, 56 deletions

diff --git a/arch/parisc/include/asm/futex.h b/arch/parisc/include/asm/futex.h
index 0ba14300cd8e..3222206cb3ea 100644
--- a/arch/parisc/include/asm/futex.h
+++ b/arch/parisc/include/asm/futex.h
@@ -1,59 +1,54 @@
+/* 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. */
+ * 256 four-word locks. We use bits 20-27 of the futex virtual
+ * address for the hash index.
+ */
+
+static inline unsigned long _futex_hash_index(unsigned long ua)
+{
+	return (ua >> 2) & 0x3fc;
+}
 
 static inline void
-_futex_spin_lock_irqsave(u32 __user *uaddr, unsigned long int *flags)
+_futex_spin_lock_irqsave(arch_spinlock_t *s, unsigned long *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)
+_futex_spin_unlock_irqrestore(arch_spinlock_t *s, unsigned long *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
-futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr)
+arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
 {
-	unsigned long int flags;
-	int op = (encoded_op >> 28) & 7;
-	int cmp = (encoded_op >> 24) & 15;
-	int oparg = (encoded_op << 8) >> 20;
-	int cmparg = (encoded_op << 20) >> 20;
+	extern u32 lws_lock_start[];
+	unsigned long ua = (unsigned long)uaddr;
+	arch_spinlock_t *s;
+	unsigned long flags;
 	int oldval, ret;
 	u32 tmp;
 
-	if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
-		oparg = 1 << oparg;
-
-	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(*uaddr)))
-		return -EFAULT;
-
-	_futex_spin_lock_irqsave(uaddr, &flags);
-	pagefault_disable();
+	s = (arch_spinlock_t *)&lws_lock_start[_futex_hash_index(ua)];
+	_futex_spin_lock_irqsave(s, &flags);
 
-	ret = -EFAULT;
-	if (unlikely(get_user(oldval, uaddr) != 0))
+	/* Return -EFAULT if we encounter a page fault or COW break */
+	if (unlikely(get_user(oldval, uaddr) != 0)) {
+		ret = -EFAULT;
 		goto out_pagefault_enable;
+	}
 
 	ret = 0;
 	tmp = oldval;
@@ -76,26 +71,18 @@ futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr)
 		break;
 	default:
 		ret = -ENOSYS;
+		goto out_pagefault_enable;
 	}
 
-	if (ret == 0 && unlikely(put_user(tmp, uaddr) != 0))
+	if (unlikely(put_user(tmp, uaddr) != 0))
 		ret = -EFAULT;
 
 out_pagefault_enable:
-	pagefault_enable();
-	_futex_spin_unlock_irqrestore(uaddr, &flags);
-
-	if (ret == 0) {
-		switch (cmp) {
-		case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
-		case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
-		case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
-		case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
-		case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
-		case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
-		default: ret = -ENOSYS;
-		}
-	}
+	_futex_spin_unlock_irqrestore(s, &flags);
+
+	if (!ret)
+		*oval = oldval;
+
 	return ret;
 }
 
@@ -103,40 +90,38 @@ static inline int
 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
 			      u32 oldval, u32 newval)
 {
+	extern u32 lws_lock_start[];
+	unsigned long ua = (unsigned long)uaddr;
+	arch_spinlock_t *s;
 	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)))
+	if (!access_ok(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.
+	 * lock selected is based on a hash of the virtual
+	 * address of the futex. This should scale to a couple
+	 * of CPUs.
 	 */
 
-	_futex_spin_lock_irqsave(uaddr, &flags);
+	s = (arch_spinlock_t *)&lws_lock_start[_futex_hash_index(ua)];
+	_futex_spin_lock_irqsave(s, &flags);
 	if (unlikely(get_user(val, uaddr) != 0)) {
-		_futex_spin_unlock_irqrestore(uaddr, &flags);
+		_futex_spin_unlock_irqrestore(s, &flags);
 		return -EFAULT;
 	}
 
 	if (val == oldval && unlikely(put_user(newval, uaddr) != 0)) {
-		_futex_spin_unlock_irqrestore(uaddr, &flags);
+		_futex_spin_unlock_irqrestore(s, &flags);
 		return -EFAULT;
 	}
 
 	*uval = val;
-	_futex_spin_unlock_irqrestore(uaddr, &flags);
+	_futex_spin_unlock_irqrestore(s, &flags);
 
 	return 0;
 }
 
-#endif /*__KERNEL__*/
 #endif /*_ASM_PARISC_FUTEX_H*/