1/*-
2 * SPDX-License-Identifier: BSD-2-Clause OR GPL-2.0
3 *
4 * Copyright (c) 2014 Mellanox Technologies. All rights reserved.
5 *
6 * This software is available to you under a choice of one of two
7 * licenses.  You may choose to be licensed under the terms of the GNU
8 * General Public License (GPL) Version 2, available from the file
9 * COPYING in the main directory of this source tree, or the
10 * OpenIB.org BSD license below:
11 *
12 *     Redistribution and use in source and binary forms, with or
13 *     without modification, are permitted provided that the following
14 *     conditions are met:
15 *
16 *      - Redistributions of source code must retain the above
17 *        copyright notice, this list of conditions and the following
18 *        disclaimer.
19 *
20 *      - Redistributions in binary form must reproduce the above
21 *        copyright notice, this list of conditions and the following
22 *        disclaimer in the documentation and/or other materials
23 *        provided with the distribution.
24 *
25 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
26 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
27 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
28 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
29 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
30 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
31 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
32 * SOFTWARE.
33 *
34 * $FreeBSD: stable/11/sys/ofed/include/rdma/ib_umem_odp.h 331772 2018-03-30 18:17:33Z hselasky $
35 */
36
37#ifndef IB_UMEM_ODP_H
38#define IB_UMEM_ODP_H
39
40#include <linux/rbtree.h>
41
42#include <rdma/ib_umem.h>
43#include <rdma/ib_verbs.h>
44
45struct umem_odp_node {
46	u64 __subtree_last;
47	struct rb_node rb;
48};
49
50struct ib_umem_odp {
51	/*
52	 * An array of the pages included in the on-demand paging umem.
53	 * Indices of pages that are currently not mapped into the device will
54	 * contain NULL.
55	 */
56	struct page		**page_list;
57	/*
58	 * An array of the same size as page_list, with DMA addresses mapped
59	 * for pages the pages in page_list. The lower two bits designate
60	 * access permissions. See ODP_READ_ALLOWED_BIT and
61	 * ODP_WRITE_ALLOWED_BIT.
62	 */
63	dma_addr_t		*dma_list;
64	/*
65	 * The umem_mutex protects the page_list and dma_list fields of an ODP
66	 * umem, allowing only a single thread to map/unmap pages. The mutex
67	 * also protects access to the mmu notifier counters.
68	 */
69	struct mutex		umem_mutex;
70	void			*private; /* for the HW driver to use. */
71
72	/* When false, use the notifier counter in the ucontext struct. */
73	bool mn_counters_active;
74	int notifiers_seq;
75	int notifiers_count;
76
77	/* A linked list of umems that don't have private mmu notifier
78	 * counters yet. */
79	struct list_head no_private_counters;
80	struct ib_umem		*umem;
81
82	/* Tree tracking */
83	struct umem_odp_node	interval_tree;
84
85	struct completion	notifier_completion;
86	int			dying;
87};
88
89#ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING
90
91int ib_umem_odp_get(struct ib_ucontext *context, struct ib_umem *umem);
92
93void ib_umem_odp_release(struct ib_umem *umem);
94
95/*
96 * The lower 2 bits of the DMA address signal the R/W permissions for
97 * the entry. To upgrade the permissions, provide the appropriate
98 * bitmask to the map_dma_pages function.
99 *
100 * Be aware that upgrading a mapped address might result in change of
101 * the DMA address for the page.
102 */
103#define ODP_READ_ALLOWED_BIT  (1<<0ULL)
104#define ODP_WRITE_ALLOWED_BIT (1<<1ULL)
105
106#define ODP_DMA_ADDR_MASK (~(ODP_READ_ALLOWED_BIT | ODP_WRITE_ALLOWED_BIT))
107
108int ib_umem_odp_map_dma_pages(struct ib_umem *umem, u64 start_offset, u64 bcnt,
109			      u64 access_mask, unsigned long current_seq);
110
111void ib_umem_odp_unmap_dma_pages(struct ib_umem *umem, u64 start_offset,
112				 u64 bound);
113
114void rbt_ib_umem_insert(struct umem_odp_node *node, struct rb_root *root);
115void rbt_ib_umem_remove(struct umem_odp_node *node, struct rb_root *root);
116typedef int (*umem_call_back)(struct ib_umem *item, u64 start, u64 end,
117			      void *cookie);
118/*
119 * Call the callback on each ib_umem in the range. Returns the logical or of
120 * the return values of the functions called.
121 */
122int rbt_ib_umem_for_each_in_range(struct rb_root *root, u64 start, u64 end,
123				  umem_call_back cb, void *cookie);
124
125struct umem_odp_node *rbt_ib_umem_iter_first(struct rb_root *root,
126					     u64 start, u64 last);
127struct umem_odp_node *rbt_ib_umem_iter_next(struct umem_odp_node *node,
128					    u64 start, u64 last);
129
130static inline int ib_umem_mmu_notifier_retry(struct ib_umem *item,
131					     unsigned long mmu_seq)
132{
133	/*
134	 * This code is strongly based on the KVM code from
135	 * mmu_notifier_retry. Should be called with
136	 * the relevant locks taken (item->odp_data->umem_mutex
137	 * and the ucontext umem_mutex semaphore locked for read).
138	 */
139
140	/* Do not allow page faults while the new ib_umem hasn't seen a state
141	 * with zero notifiers yet, and doesn't have its own valid set of
142	 * private counters. */
143	if (!item->odp_data->mn_counters_active)
144		return 1;
145
146	if (unlikely(item->odp_data->notifiers_count))
147		return 1;
148	if (item->odp_data->notifiers_seq != mmu_seq)
149		return 1;
150	return 0;
151}
152
153#else /* CONFIG_INFINIBAND_ON_DEMAND_PAGING */
154
155static inline int ib_umem_odp_get(struct ib_ucontext *context,
156				  struct ib_umem *umem)
157{
158	return -EINVAL;
159}
160
161static inline void ib_umem_odp_release(struct ib_umem *umem) {}
162
163#endif /* CONFIG_INFINIBAND_ON_DEMAND_PAGING */
164
165#endif /* IB_UMEM_ODP_H */
166