[mirror_ubuntu-zesty-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.
 *
 */

/**
 * 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
futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr)
{
	int op = (encoded_op >> 28) & 7;
	int cmp = (encoded_op >> 24) & 15;
	int oparg = (encoded_op << 8) >> 20;
	int cmparg = (encoded_op << 20) >> 20;
	int oldval, ret;
	u32 tmp;

	if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
		oparg = 1 << oparg;

	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) {
		switch (cmp) {
		case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
		case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
		case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
		case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
		case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
		case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
		default: ret = -ENOSYS;
		}
	}
	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;

	if (unlikely(get_user(val, uaddr) != 0))
		return -EFAULT;

	if (val == oldval && unlikely(put_user(newval, uaddr) != 0))
		return -EFAULT;

	*uval = val;

	return 0;
}

#else
static inline int
futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr)
{
	int op = (encoded_op >> 28) & 7;
	int cmp = (encoded_op >> 24) & 15;
	int oparg = (encoded_op << 8) >> 20;
	int cmparg = (encoded_op << 20) >> 20;
	int oldval = 0, ret;
	if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
		oparg = 1 << oparg;

	if (! access_ok (VERIFY_WRITE, uaddr, sizeof(u32)))
		return -EFAULT;

	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) {
		switch (cmp) {
		case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
		case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
		case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
		case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
		case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
		case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
		default: ret = -ENOSYS;
		}
	}
	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	/**
	16	* futex_atomic_op_inuser() - Atomic arithmetic operation with constant
	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
	28	futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr)
	29	{
	30	int op = (encoded_op >> 28) & 7;
	31	int cmp = (encoded_op >> 24) & 15;
	32	int oparg = (encoded_op << 8) >> 20;
	33	int cmparg = (encoded_op << 20) >> 20;
	34	int oldval, ret;
	35	u32 tmp;
	36
	37	if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
	38	oparg = 1 << oparg;
	39
f3dae07e	40	preempt_disable();
00f634bc LFT	41	pagefault_disable();
	42
	43	ret = -EFAULT;
	44	if (unlikely(get_user(oldval, uaddr) != 0))
	45	goto out_pagefault_enable;
	46
	47	ret = 0;
	48	tmp = oldval;
	49
	50	switch (op) {
	51	case FUTEX_OP_SET:
	52	tmp = oparg;
	53	break;
	54	case FUTEX_OP_ADD:
	55	tmp += oparg;
	56	break;
	57	case FUTEX_OP_OR:
	58	tmp \|= oparg;
	59	break;
	60	case FUTEX_OP_ANDN:
	61	tmp &= ~oparg;
	62	break;
	63	case FUTEX_OP_XOR:
	64	tmp ^= oparg;
	65	break;
	66	default:
	67	ret = -ENOSYS;
	68	}
	69
	70	if (ret == 0 && unlikely(put_user(tmp, uaddr) != 0))
	71	ret = -EFAULT;
	72
	73	out_pagefault_enable:
	74	pagefault_enable();
f3dae07e	75	preempt_enable();
00f634bc LFT	76
	77	if (ret == 0) {
	78	switch (cmp) {
	79	case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
	80	case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
	81	case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
	82	case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
	83	case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
	84	case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
	85	default: ret = -ENOSYS;
	86	}
	87	}
	88	return ret;
	89	}
	90
	91	/**
	92	* futex_atomic_cmpxchg_inatomic() - Compare and exchange the content of the
	93	* uaddr with newval if the current value is
	94	* oldval.
	95	* @uval: pointer to store content of @uaddr
	96	* @uaddr: pointer to user space address
	97	* @oldval: old value
	98	* @newval: new value to store to @uaddr
	99	*
	100	* Return:
	101	* 0 - On success
	102	* <0 - On error
	103	*/
	104	static inline int
	105	futex_atomic_cmpxchg_inatomic(u32 uval, u32 __user uaddr,
	106	u32 oldval, u32 newval)
	107	{
	108	u32 val;
	109
	110	if (unlikely(get_user(val, uaddr) != 0))
	111	return -EFAULT;
	112
	113	if (val == oldval && unlikely(put_user(newval, uaddr) != 0))
	114	return -EFAULT;
	115
	116	*uval = val;
	117
	118	return 0;
	119	}
	120
	121	#else
f8aaeace	122	static inline int
8d7718aa	123	futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr)
f8aaeace JD	124	{
	125	int op = (encoded_op >> 28) & 7;
	126	int cmp = (encoded_op >> 24) & 15;
	127	int oparg = (encoded_op << 8) >> 20;
	128	int cmparg = (encoded_op << 20) >> 20;
	129	int oldval = 0, ret;
	130	if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
	131	oparg = 1 << oparg;
	132
8d7718aa	133	if (! access_ok (VERIFY_WRITE, uaddr, sizeof(u32)))
f8aaeace JD	134	return -EFAULT;
f8aaeace JD	135
a866374a	136	pagefault_disable();
f8aaeace JD	137
	138	switch (op) {
	139	case FUTEX_OP_SET:
	140	case FUTEX_OP_ADD:
	141	case FUTEX_OP_OR:
	142	case FUTEX_OP_ANDN:
	143	case FUTEX_OP_XOR:
	144	default:
	145	ret = -ENOSYS;
	146	}
	147
a866374a	148	pagefault_enable();
f8aaeace JD	149
	150	if (!ret) {
	151	switch (cmp) {
	152	case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
	153	case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
	154	case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
	155	case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
	156	case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
	157	case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
	158	default: ret = -ENOSYS;
	159	}
	160	}
	161	return ret;
	162	}
	163
e9056f13	164	static inline int
8d7718aa ML	165	futex_atomic_cmpxchg_inatomic(u32 uval, u32 __user uaddr,
8d7718aa ML	166	u32 oldval, u32 newval)
e9056f13 IM	167	{
	168	return -ENOSYS;
	169	}
	170
00f634bc	171	#endif /* CONFIG_SMP */
f8aaeace	172	#endif