Viewing file:  futex.h (2.9 KB) -rw-r--r--
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#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;
u32 val;
int oldval = 0, ret;
pagefault_disable();
_futex_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;
}
_futex_spin_unlock_irqrestore(uaddr, &flags);
pagefault_enable();
if (!ret)
*oval = oldval;
return ret;
}
/* Non-atomic version */
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...
*/
if (segment_eq(KERNEL_DS, get_fs()) && !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);
ret = get_user(val, uaddr);
if (!ret && val == oldval)
ret = put_user(newval, uaddr);
*uval = val;
_futex_spin_unlock_irqrestore(uaddr, &flags);
return ret;
}
#endif /*__KERNEL__*/
#endif /*_ASM_PARISC_FUTEX_H*/
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