You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
151 lines
2.9 KiB
151 lines
2.9 KiB
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef _ASM_GENERIC_FUTEX_H
|
|
#define _ASM_GENERIC_FUTEX_H
|
|
|
|
#include <linux/futex.h>
|
|
#include <linux/uaccess.h>
|
|
#include <asm/errno.h>
|
|
|
|
#ifndef CONFIG_SMP
|
|
/*
|
|
* The following implementation only for uniprocessor machines.
|
|
* It relies on preempt_disable() ensuring mutual exclusion.
|
|
*
|
|
*/
|
|
|
|
/**
|
|
* arch_futex_atomic_op_inuser() - Atomic arithmetic operation with constant
|
|
* argument and comparison of the previous
|
|
* futex value with another constant.
|
|
*
|
|
* @encoded_op: encoded operation to execute
|
|
* @uaddr: pointer to user space address
|
|
*
|
|
* Return:
|
|
* 0 - On success
|
|
* -EFAULT - User access resulted in a page fault
|
|
* -EAGAIN - Atomic operation was unable to complete due to contention
|
|
* -ENOSYS - Operation not supported
|
|
*/
|
|
static inline int
|
|
arch_futex_atomic_op_inuser(int op, u32 oparg, int *oval, u32 __user *uaddr)
|
|
{
|
|
int oldval, ret;
|
|
u32 tmp;
|
|
|
|
preempt_disable();
|
|
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();
|
|
preempt_enable();
|
|
|
|
if (ret == 0)
|
|
*oval = oldval;
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* futex_atomic_cmpxchg_inatomic() - Compare and exchange the content of the
|
|
* uaddr with newval if the current value is
|
|
* oldval.
|
|
* @uval: pointer to store content of @uaddr
|
|
* @uaddr: pointer to user space address
|
|
* @oldval: old value
|
|
* @newval: new value to store to @uaddr
|
|
*
|
|
* Return:
|
|
* 0 - On success
|
|
* -EFAULT - User access resulted in a page fault
|
|
* -EAGAIN - Atomic operation was unable to complete due to contention
|
|
* -ENOSYS - Function not implemented (only if !HAVE_FUTEX_CMPXCHG)
|
|
*/
|
|
static inline int
|
|
futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
|
|
u32 oldval, u32 newval)
|
|
{
|
|
u32 val;
|
|
|
|
preempt_disable();
|
|
if (unlikely(get_user(val, uaddr) != 0)) {
|
|
preempt_enable();
|
|
return -EFAULT;
|
|
}
|
|
|
|
if (val == oldval && unlikely(put_user(newval, uaddr) != 0)) {
|
|
preempt_enable();
|
|
return -EFAULT;
|
|
}
|
|
|
|
*uval = val;
|
|
preempt_enable();
|
|
|
|
return 0;
|
|
}
|
|
|
|
#else
|
|
static inline int
|
|
arch_futex_atomic_op_inuser(int op, u32 oparg, int *oval, u32 __user *uaddr)
|
|
{
|
|
int oldval = 0, ret;
|
|
|
|
pagefault_disable();
|
|
|
|
switch (op) {
|
|
case FUTEX_OP_SET:
|
|
case FUTEX_OP_ADD:
|
|
case FUTEX_OP_OR:
|
|
case FUTEX_OP_ANDN:
|
|
case FUTEX_OP_XOR:
|
|
default:
|
|
ret = -ENOSYS;
|
|
}
|
|
|
|
pagefault_enable();
|
|
|
|
if (!ret)
|
|
*oval = oldval;
|
|
|
|
return ret;
|
|
}
|
|
|
|
static inline int
|
|
futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
|
|
u32 oldval, u32 newval)
|
|
{
|
|
return -ENOSYS;
|
|
}
|
|
|
|
#endif /* CONFIG_SMP */
|
|
#endif
|
|
|