1/*
  2 * Copyright 2010 Tilera Corporation. All Rights Reserved.
  3 *
  4 *   This program is free software; you can redistribute it and/or
  5 *   modify it under the terms of the GNU General Public License
  6 *   as published by the Free Software Foundation, version 2.
  7 *
  8 *   This program is distributed in the hope that it will be useful, but
  9 *   WITHOUT ANY WARRANTY; without even the implied warranty of
 10 *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 11 *   NON INFRINGEMENT.  See the GNU General Public License for
 12 *   more details.
 13 *
 14 * These routines make two important assumptions:
 15 *
 16 * 1. atomic_t is really an int and can be freely cast back and forth
 17 *    (validated in __init_atomic_per_cpu).
 18 *
 19 * 2. userspace uses sys_cmpxchg() for all atomic operations, thus using
 20 *    the same locking convention that all the kernel atomic routines use.
 21 */
 22
 23#ifndef _ASM_TILE_FUTEX_H
 24#define _ASM_TILE_FUTEX_H
 25
 26#ifndef __ASSEMBLY__
 27
 28#include <linux/futex.h>
 29#include <linux/uaccess.h>
 30#include <linux/errno.h>
 31
 32extern struct __get_user futex_set(u32 __user *v, int i);
 33extern struct __get_user futex_add(u32 __user *v, int n);
 34extern struct __get_user futex_or(u32 __user *v, int n);
 35extern struct __get_user futex_andn(u32 __user *v, int n);
 36extern struct __get_user futex_cmpxchg(u32 __user *v, int o, int n);
 37
 38#ifndef __tilegx__
 39extern struct __get_user futex_xor(u32 __user *v, int n);
 40#else
 41static inline struct __get_user futex_xor(u32 __user *uaddr, int n)
 42{
 43	struct __get_user asm_ret = __get_user_4(uaddr);
 44	if (!asm_ret.err) {
 45		int oldval, newval;
 46		do {
 47			oldval = asm_ret.val;
 48			newval = oldval ^ n;
 49			asm_ret = futex_cmpxchg(uaddr, oldval, newval);
 50		} while (asm_ret.err == 0 && oldval != asm_ret.val);
 51	}
 52	return asm_ret;
 53}
 54#endif
 55
 56static inline int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr)
 57{
 58	int op = (encoded_op >> 28) & 7;
 59	int cmp = (encoded_op >> 24) & 15;
 60	int oparg = (encoded_op << 8) >> 20;
 61	int cmparg = (encoded_op << 20) >> 20;
 62	int ret;
 63	struct __get_user asm_ret;
 64
 65	if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
 66		oparg = 1 << oparg;
 67
 68	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
 69		return -EFAULT;
 70
 71	pagefault_disable();
 72	switch (op) {
 73	case FUTEX_OP_SET:
 74		asm_ret = futex_set(uaddr, oparg);
 75		break;
 76	case FUTEX_OP_ADD:
 77		asm_ret = futex_add(uaddr, oparg);
 78		break;
 79	case FUTEX_OP_OR:
 80		asm_ret = futex_or(uaddr, oparg);
 81		break;
 82	case FUTEX_OP_ANDN:
 83		asm_ret = futex_andn(uaddr, oparg);
 84		break;
 85	case FUTEX_OP_XOR:
 86		asm_ret = futex_xor(uaddr, oparg);
 87		break;
 88	default:
 89		asm_ret.err = -ENOSYS;
 90	}
 91	pagefault_enable();
 92
 93	ret = asm_ret.err;
 94
 95	if (!ret) {
 96		switch (cmp) {
 97		case FUTEX_OP_CMP_EQ:
 98			ret = (asm_ret.val == cmparg);
 99			break;
100		case FUTEX_OP_CMP_NE:
101			ret = (asm_ret.val != cmparg);
102			break;
103		case FUTEX_OP_CMP_LT:
104			ret = (asm_ret.val < cmparg);
105			break;
106		case FUTEX_OP_CMP_GE:
107			ret = (asm_ret.val >= cmparg);
108			break;
109		case FUTEX_OP_CMP_LE:
110			ret = (asm_ret.val <= cmparg);
111			break;
112		case FUTEX_OP_CMP_GT:
113			ret = (asm_ret.val > cmparg);
114			break;
115		default:
116			ret = -ENOSYS;
117		}
118	}
119	return ret;
120}
121
122static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
123						u32 oldval, u32 newval)
124{
125	struct __get_user asm_ret;
126
127	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
128		return -EFAULT;
129
130	asm_ret = futex_cmpxchg(uaddr, oldval, newval);
131	*uval = asm_ret.val;
132	return asm_ret.err;
133}
134
135#ifndef __tilegx__
136/* Return failure from the atomic wrappers. */
137struct __get_user __atomic_bad_address(int __user *addr);
138#endif
139
140#endif /* !__ASSEMBLY__ */
141
142#endif /* _ASM_TILE_FUTEX_H */