[mirror_ubuntu-artful-kernel.git] / include / asm-generic / futex.h

#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
 * <0 - On error
 */
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
 * <0 - On error
 */
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
Commit	Line	Data
f8aaeace JD	1	#ifndef _ASM_GENERIC_FUTEX_H
	2	#define _ASM_GENERIC_FUTEX_H
	3
f8aaeace	4	#include <linux/futex.h>
730f412c	5	#include <linux/uaccess.h>
f8aaeace	6	#include <asm/errno.h>
f8aaeace	7
00f634bc LFT	8	#ifndef CONFIG_SMP
	9	/*
	10	* The following implementation only for uniprocessor machines.
f3dae07e	11	* It relies on preempt_disable() ensuring mutual exclusion.
00f634bc LFT	12	*
	13	*/
	14
	15	/**
5961958c	16	* arch_futex_atomic_op_inuser() - Atomic arithmetic operation with constant
00f634bc LFT	17	* argument and comparison of the previous
	18	* futex value with another constant.
	19	*
	20	* @encoded_op: encoded operation to execute
	21	* @uaddr: pointer to user space address
	22	*
	23	* Return:
	24	* 0 - On success
	25	* <0 - On error
	26	*/
	27	static inline int
5961958c	28	arch_futex_atomic_op_inuser(int op, u32 oparg, int oval, u32 __user uaddr)
00f634bc	29	{
00f634bc LFT	30	int oldval, ret;
	31	u32 tmp;
	32
f3dae07e	33	preempt_disable();
00f634bc LFT	34	pagefault_disable();
	35
	36	ret = -EFAULT;
	37	if (unlikely(get_user(oldval, uaddr) != 0))
	38	goto out_pagefault_enable;
	39
	40	ret = 0;
	41	tmp = oldval;
	42
	43	switch (op) {
	44	case FUTEX_OP_SET:
	45	tmp = oparg;
	46	break;
	47	case FUTEX_OP_ADD:
	48	tmp += oparg;
	49	break;
	50	case FUTEX_OP_OR:
	51	tmp \|= oparg;
	52	break;
	53	case FUTEX_OP_ANDN:
	54	tmp &= ~oparg;
	55	break;
	56	case FUTEX_OP_XOR:
	57	tmp ^= oparg;
	58	break;
	59	default:
	60	ret = -ENOSYS;
	61	}
	62
	63	if (ret == 0 && unlikely(put_user(tmp, uaddr) != 0))
	64	ret = -EFAULT;
	65
	66	out_pagefault_enable:
	67	pagefault_enable();
f3dae07e	68	preempt_enable();
00f634bc	69
5961958c JS	70	if (ret == 0)
	71	*oval = oldval;
	72
00f634bc LFT	73	return ret;
	74	}
	75
	76	/**
	77	* futex_atomic_cmpxchg_inatomic() - Compare and exchange the content of the
	78	* uaddr with newval if the current value is
	79	* oldval.
	80	* @uval: pointer to store content of @uaddr
	81	* @uaddr: pointer to user space address
	82	* @oldval: old value
	83	* @newval: new value to store to @uaddr
	84	*
	85	* Return:
	86	* 0 - On success
	87	* <0 - On error
	88	*/
	89	static inline int
	90	futex_atomic_cmpxchg_inatomic(u32 uval, u32 __user uaddr,
	91	u32 oldval, u32 newval)
	92	{
	93	u32 val;
	94
d9b9ff8c	95	preempt_disable();
fba7cd68 RP	96	if (unlikely(get_user(val, uaddr) != 0)) {
fba7cd68 RP	97	preempt_enable();
00f634bc	98	return -EFAULT;
fba7cd68	99	}
00f634bc	100
fba7cd68 RP	101	if (val == oldval && unlikely(put_user(newval, uaddr) != 0)) {
fba7cd68 RP	102	preempt_enable();
00f634bc	103	return -EFAULT;
fba7cd68	104	}
00f634bc LFT	105
00f634bc LFT	106	*uval = val;
d9b9ff8c	107	preempt_enable();
00f634bc LFT	108
	109	return 0;
	110	}
	111
	112	#else
f8aaeace	113	static inline int
5961958c	114	arch_futex_atomic_op_inuser(int op, u32 oparg, int oval, u32 __user uaddr)
f8aaeace	115	{
f8aaeace	116	int oldval = 0, ret;
f8aaeace	117
a866374a	118	pagefault_disable();
f8aaeace JD	119
	120	switch (op) {
	121	case FUTEX_OP_SET:
	122	case FUTEX_OP_ADD:
	123	case FUTEX_OP_OR:
	124	case FUTEX_OP_ANDN:
	125	case FUTEX_OP_XOR:
	126	default:
	127	ret = -ENOSYS;
	128	}
	129
a866374a	130	pagefault_enable();
f8aaeace	131
5961958c JS	132	if (!ret)
	133	*oval = oldval;
	134
f8aaeace JD	135	return ret;
	136	}
	137
e9056f13	138	static inline int
8d7718aa ML	139	futex_atomic_cmpxchg_inatomic(u32 uval, u32 __user uaddr,
8d7718aa ML	140	u32 oldval, u32 newval)
e9056f13 IM	141	{
	142	return -ENOSYS;
	143	}
	144
00f634bc	145	#endif /* CONFIG_SMP */
f8aaeace	146	#endif