1 /*
2  * Copyright (c) 2006, 2007, 2008, 2009 QLogic Corporation. All rights reserved.
3  * Copyright (c) 2003, 2004, 2005, 2006 PathScale, Inc. All rights reserved.
4  *
5  * This software is available to you under a choice of one of two
6  * licenses.  You may choose to be licensed under the terms of the GNU
7  * General Public License (GPL) Version 2, available from the file
8  * COPYING in the main directory of this source tree, or the
9  * OpenIB.org BSD license below:
10  *
11  *     Redistribution and use in source and binary forms, with or
12  *     without modification, are permitted provided that the following
13  *     conditions are met:
14  *
15  *      - Redistributions of source code must retain the above
16  *        copyright notice, this list of conditions and the following
17  *        disclaimer.
18  *
19  *      - Redistributions in binary form must reproduce the above
20  *        copyright notice, this list of conditions and the following
21  *        disclaimer in the documentation and/or other materials
22  *        provided with the distribution.
23  *
24  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
25  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
26  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
27  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
28  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
29  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
30  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
31  * SOFTWARE.
32  */
33 
34 #include <linux/mm.h>
35 #include <linux/sched/signal.h>
36 #include <linux/device.h>
37 
38 #include "qib.h"
39 
40 static void __qib_release_user_pages(struct page **p, size_t num_pages,
41 				     int dirty)
42 {
43 	size_t i;
44 
45 	for (i = 0; i < num_pages; i++) {
46 		if (dirty)
47 			set_page_dirty_lock(p[i]);
48 		put_page(p[i]);
49 	}
50 }
51 
52 /*
53  * Call with current->mm->mmap_sem held.
54  */
55 static int __qib_get_user_pages(unsigned long start_page, size_t num_pages,
56 				struct page **p)
57 {
58 	unsigned long lock_limit;
59 	size_t got;
60 	int ret;
61 
62 	lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
63 
64 	if (num_pages > lock_limit && !capable(CAP_IPC_LOCK)) {
65 		ret = -ENOMEM;
66 		goto bail;
67 	}
68 
69 	for (got = 0; got < num_pages; got += ret) {
70 		ret = get_user_pages(start_page + got * PAGE_SIZE,
71 				     num_pages - got,
72 				     FOLL_WRITE | FOLL_FORCE,
73 				     p + got, NULL);
74 		if (ret < 0)
75 			goto bail_release;
76 	}
77 
78 	current->mm->pinned_vm += num_pages;
79 
80 	ret = 0;
81 	goto bail;
82 
83 bail_release:
84 	__qib_release_user_pages(p, got, 0);
85 bail:
86 	return ret;
87 }
88 
89 /**
90  * qib_map_page - a safety wrapper around pci_map_page()
91  *
92  * A dma_addr of all 0's is interpreted by the chip as "disabled".
93  * Unfortunately, it can also be a valid dma_addr returned on some
94  * architectures.
95  *
96  * The powerpc iommu assigns dma_addrs in ascending order, so we don't
97  * have to bother with retries or mapping a dummy page to insure we
98  * don't just get the same mapping again.
99  *
100  * I'm sure we won't be so lucky with other iommu's, so FIXME.
101  */
102 dma_addr_t qib_map_page(struct pci_dev *hwdev, struct page *page,
103 			unsigned long offset, size_t size, int direction)
104 {
105 	dma_addr_t phys;
106 
107 	phys = pci_map_page(hwdev, page, offset, size, direction);
108 
109 	if (phys == 0) {
110 		pci_unmap_page(hwdev, phys, size, direction);
111 		phys = pci_map_page(hwdev, page, offset, size, direction);
112 		/*
113 		 * FIXME: If we get 0 again, we should keep this page,
114 		 * map another, then free the 0 page.
115 		 */
116 	}
117 
118 	return phys;
119 }
120 
121 /**
122  * qib_get_user_pages - lock user pages into memory
123  * @start_page: the start page
124  * @num_pages: the number of pages
125  * @p: the output page structures
126  *
127  * This function takes a given start page (page aligned user virtual
128  * address) and pins it and the following specified number of pages.  For
129  * now, num_pages is always 1, but that will probably change at some point
130  * (because caller is doing expected sends on a single virtually contiguous
131  * buffer, so we can do all pages at once).
132  */
133 int qib_get_user_pages(unsigned long start_page, size_t num_pages,
134 		       struct page **p)
135 {
136 	int ret;
137 
138 	down_write(&current->mm->mmap_sem);
139 
140 	ret = __qib_get_user_pages(start_page, num_pages, p);
141 
142 	up_write(&current->mm->mmap_sem);
143 
144 	return ret;
145 }
146 
147 void qib_release_user_pages(struct page **p, size_t num_pages)
148 {
149 	if (current->mm) /* during close after signal, mm can be NULL */
150 		down_write(&current->mm->mmap_sem);
151 
152 	__qib_release_user_pages(p, num_pages, 1);
153 
154 	if (current->mm) {
155 		current->mm->pinned_vm -= num_pages;
156 		up_write(&current->mm->mmap_sem);
157 	}
158 }
159