1 files changed, 37 insertions, 22 deletions

diff --git a/arch/parisc/include/asm/futex.h b/arch/parisc/include/asm/futex.h
index 9cd4dd6e63ad..b5835325d44b 100644
--- a/arch/parisc/include/asm/futex.h
+++ b/arch/parisc/include/asm/futex.h
@@ -8,39 +8,47 @@
 #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(u32 __user *uaddr)
+_futex_spin_lock_irqsave(arch_spinlock_t *s, unsigned long *flags)
 {
-	extern u32 lws_lock_start[];
-	long index = ((long)uaddr & 0x7f8) >> 1;
-	arch_spinlock_t *s = (arch_spinlock_t *)&lws_lock_start[index];
-	preempt_disable();
+	local_irq_save(*flags);
 	arch_spin_lock(s);
 }
 
 static inline void
-_futex_spin_unlock(u32 __user *uaddr)
+_futex_spin_unlock_irqrestore(arch_spinlock_t *s, unsigned long *flags)
 {
-	extern u32 lws_lock_start[];
-	long index = ((long)uaddr & 0x7f8) >> 1;
-	arch_spinlock_t *s = (arch_spinlock_t *)&lws_lock_start[index];
 	arch_spin_unlock(s);
-	preempt_enable();
+	local_irq_restore(*flags);
 }
 
 static inline int
 arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
 {
+	extern u32 lws_lock_start[];
+	unsigned long ua = (unsigned long)uaddr;
+	arch_spinlock_t *s;
+	unsigned long flags;
 	int oldval, ret;
 	u32 tmp;
 
-	ret = -EFAULT;
+	s = (arch_spinlock_t *)&lws_lock_start[_futex_hash_index(ua)];
+	_futex_spin_lock_irqsave(s, &flags);
 
-	_futex_spin_lock(uaddr);
-	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;
@@ -63,13 +71,14 @@ arch_futex_atomic_op_inuser(int op, int oparg, int *oval, 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:
-	_futex_spin_unlock(uaddr);
+	_futex_spin_unlock_irqrestore(s, &flags);
 
 	if (!ret)
 		*oval = oldval;
@@ -81,7 +90,11 @@ 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...
@@ -94,23 +107,25 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
 
 	/* 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(uaddr);
+	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(uaddr);
+		_futex_spin_unlock_irqrestore(s, &flags);
 		return -EFAULT;
 	}
 
 	if (val == oldval && unlikely(put_user(newval, uaddr) != 0)) {
-		_futex_spin_unlock(uaddr);
+		_futex_spin_unlock_irqrestore(s, &flags);
 		return -EFAULT;
 	}
 
 	*uval = val;
-	_futex_spin_unlock(uaddr);
+	_futex_spin_unlock_irqrestore(s, &flags);
 
 	return 0;
 }