1 /*-
2 * Copyright (c) 2011 The FreeBSD Foundation
3 * Copyright (c) 2014-2020 François Tigeot <ftigeot@wolfpond.org>
4 * All rights reserved.
5 *
6 * Portions of this software were developed by Konstantin Belousov
7 * under sponsorship from the FreeBSD Foundation.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 *
30 */
31
32 #include <vm/vm.h>
33 #include <vm/vm_page.h>
34 #include <vm/vm_page2.h>
35 #include <vm/vm_pager.h>
36 #include <vm/vm_extern.h>
37
38 #include <linux/err.h>
39 #include <linux/shmem_fs.h>
40
41 /*
42 * This code is typically called with a normal VM object to access
43 * data from a userspace shared memory mapping. However, handle the
44 * case where it might be called with OBJT_MGTDEVICE anyway.
45 */
46 struct page *
shmem_read_mapping_page(vm_object_t object,vm_pindex_t pindex)47 shmem_read_mapping_page(vm_object_t object, vm_pindex_t pindex)
48 {
49 vm_page_t m;
50 int rv;
51
52 VM_OBJECT_LOCK(object);
53 if (object->type == OBJT_MGTDEVICE) {
54 m = NULL;
55 rv = vm_pager_get_page(object, pindex, &m, 1);
56 if (m == NULL)
57 return ERR_PTR(-ENOMEM);
58 if (rv != VM_PAGER_OK) {
59 vm_page_free(m);
60 return ERR_PTR(-ENOMEM);
61 }
62 } else {
63 m = vm_page_grab(object, pindex,
64 VM_ALLOC_NORMAL | VM_ALLOC_RETRY);
65 if (m->valid != VM_PAGE_BITS_ALL) {
66 if (vm_pager_has_page(object, pindex)) {
67 rv = vm_pager_get_page(object, pindex, &m, 1);
68 m = vm_page_lookup(object, pindex);
69 if (m == NULL)
70 return ERR_PTR(-ENOMEM);
71 if (rv != VM_PAGER_OK) {
72 vm_page_free(m);
73 return ERR_PTR(-ENOMEM);
74 }
75 } else {
76 pmap_zero_page(VM_PAGE_TO_PHYS(m));
77 m->valid = VM_PAGE_BITS_ALL;
78 m->dirty = 0;
79 }
80 }
81 }
82 vm_page_wire(m); /* put_page() undoes this */
83 vm_page_wakeup(m);
84 VM_OBJECT_UNLOCK(object);
85
86 return (struct page *)m;
87 }
88
89 struct page *
shmem_read_mapping_page_gfp(struct vm_object * mapping,pgoff_t index,gfp_t gfp_mask)90 shmem_read_mapping_page_gfp(struct vm_object *mapping,
91 pgoff_t index, gfp_t gfp_mask)
92 {
93 return shmem_read_mapping_page(mapping, index);
94 }
95
96 #include <linux/fs.h>
97
98 int
pagecache_write_begin(struct vm_object * obj,struct address_space * mapping,loff_t pos,unsigned len,unsigned flags,struct page ** pagep,void ** fsdata)99 pagecache_write_begin(struct vm_object *obj, struct address_space *mapping,
100 loff_t pos, unsigned len, unsigned flags, struct page **pagep, void **fsdata)
101 {
102 *pagep = shmem_read_mapping_page(obj, OFF_TO_IDX(pos));
103
104 return 0;
105 }
106
107 /* This is really shmem_write_end() for the i915 gem code */
108 int
pagecache_write_end(struct vm_object * obj,struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct page * page,void * fsdata)109 pagecache_write_end(struct vm_object *obj, struct address_space *mapping,
110 loff_t pos, unsigned len, unsigned copied, struct page *page, void *fsdata)
111 {
112 set_page_dirty(page);
113 put_page(page);
114
115 return copied;
116 }
117
118 /*
119 * userptr support
120 */
121 long
get_user_pages(unsigned long start,unsigned long nr_pages,unsigned int gup_flags,struct page ** pages,struct vm_area_struct ** vmas)122 get_user_pages(unsigned long start, unsigned long nr_pages,
123 unsigned int gup_flags, struct page **pages,
124 struct vm_area_struct **vmas)
125 {
126 thread_t td;
127 vm_page_t m;
128 vm_map_t map;
129 long i;
130 int error;
131 int busied;
132 int fault_type = VM_PROT_READ;
133
134 /* returning related vmas not yet supported */
135 td = curthread;
136 KKASSERT(vmas == NULL);
137 KKASSERT(td->td_proc == NULL);
138 map = &td->td_proc->p_vmspace->vm_map;
139
140 if (gup_flags)
141 fault_type |= VM_PROT_WRITE;
142
143 error = 0;
144 for (i = 0; i < nr_pages; ++i) {
145 m = vm_fault_page(map, start + i * PAGE_SIZE,
146 fault_type, VM_FAULT_NORMAL,
147 &error, &busied);
148 if (error)
149 break;
150 if (busied) {
151 vm_page_wire(m);
152 } else {
153 vm_page_busy_wait(m, TRUE, "drmgup");
154 vm_page_wire(m);
155 vm_page_unhold(m);
156 }
157 vm_page_wakeup(m);
158 pages[i] = (void *)m;
159 }
160 if (error) {
161 while (--i >= 0) {
162 put_page(pages[i]);
163 pages[i] = NULL;
164 }
165 i = -error;
166 }
167 return i;
168 }
169
170 void
release_pages(struct page ** pages,unsigned long nr_pages)171 release_pages(struct page **pages, unsigned long nr_pages)
172 {
173 while (nr_pages > 0) {
174 --nr_pages;
175 put_page(pages[nr_pages]);
176 pages[nr_pages] = NULL;
177 }
178 }
179