Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit d9ba5fe7 authored by Carlos O'Donell's avatar Carlos O'Donell Committed by James Bottomley
Browse files

[PARISC] Fix futex support 



Implements futex op support and makes futex cmpxchg atomic.
Tested on 64-bit SMP kernel running on 2 x PA8700s.

[jejb: checkpatch fixes]
Signed-off-by: default avatarCarlos O'Donell <carlos@systemhalted.org>
Tested-by: default avatarJohn David Anglin <dave.anglin@bell.net>
Cc: stable@kernel.org
Signed-off-by: default avatarJames Bottomley <JBottomley@Parallels.com>
parent 1765a367

arch/parisc/include/asm/futex.h

+60 −6
Original line number Diff line number Diff line
@@ -5,11 +5,14 @@ 


#include <linux/futex.h>

#include <linux/uaccess.h>

#include <asm/atomic.h>

#include <asm/errno.h>



static inline int

futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr)

{

	unsigned long int flags;

	u32 val;

	int op = (encoded_op >> 28) & 7;

	int cmp = (encoded_op >> 24) & 15;

	int oparg = (encoded_op << 8) >> 20;
@@ -18,21 +21,58 @@ futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr) 
	if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))

		oparg = 1 << oparg;



	if (! access_ok (VERIFY_WRITE, uaddr, sizeof(u32)))

	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(*uaddr)))

		return -EFAULT;



	pagefault_disable();



	_atomic_spin_lock_irqsave(uaddr, flags);



	switch (op) {

	case FUTEX_OP_SET:

		/* *(int *)UADDR2 = OPARG; */

		ret = get_user(oldval, uaddr);

		if (!ret)

			ret = put_user(oparg, uaddr);

		break;

	case FUTEX_OP_ADD:

		/* *(int *)UADDR2 += OPARG; */

		ret = get_user(oldval, uaddr);

		if (!ret) {

			val = oldval + oparg;

			ret = put_user(val, uaddr);

		}

		break;

	case FUTEX_OP_OR:

		/* *(int *)UADDR2 |= OPARG; */

		ret = get_user(oldval, uaddr);

		if (!ret) {

			val = oldval | oparg;

			ret = put_user(val, uaddr);

		}

		break;

	case FUTEX_OP_ANDN:

		/* *(int *)UADDR2 &= ~OPARG; */

		ret = get_user(oldval, uaddr);

		if (!ret) {

			val = oldval & ~oparg;

			ret = put_user(val, uaddr);

		}

		break;

	case FUTEX_OP_XOR:

		/* *(int *)UADDR2 ^= OPARG; */

		ret = get_user(oldval, uaddr);

		if (!ret) {

			val = oldval ^ oparg;

			ret = put_user(val, uaddr);

		}

		break;

	default:

		ret = -ENOSYS;

	}



	_atomic_spin_unlock_irqrestore(uaddr, flags);



	pagefault_enable();



	if (!ret) {
@@ -54,7 +94,9 @@ static inline int 
futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,

			      u32 oldval, u32 newval)

{

	int ret;

	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...
@@ -65,12 +107,24 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, 
	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))

		return -EFAULT;



	if (get_user(val, uaddr))

		return -EFAULT;

	if (val == oldval && put_user(newval, uaddr))

		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.

	 */



	_atomic_spin_lock_irqsave(uaddr, flags);



	ret = get_user(val, uaddr);



	if (!ret && val == oldval)

		ret = put_user(newval, uaddr);



	*uval = val;

	return 0;



	_atomic_spin_unlock_irqrestore(uaddr, flags);



	return ret;

}



#endif /*__KERNEL__*/