1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2000 Peter Wemm
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28 #include <sys/param.h>
29 #include <sys/systm.h>
30 #include <sys/conf.h>
31 #include <sys/kernel.h>
32 #include <sys/lock.h>
33 #include <sys/proc.h>
34 #include <sys/mutex.h>
35 #include <sys/mman.h>
36 #include <sys/pctrie.h>
37 #include <sys/rwlock.h>
38 #include <sys/sysctl.h>
39 #include <sys/user.h>
40
41 #include <vm/vm.h>
42 #include <vm/vm_param.h>
43 #include <vm/vm_object.h>
44 #include <vm/vm_page.h>
45 #include <vm/vm_pageout.h>
46 #include <vm/vm_pager.h>
47
48 /* list of phys pager objects */
49 static struct pagerlst phys_pager_object_list;
50 /* protect access to phys_pager_object_list */
51 static struct mtx phys_pager_mtx;
52
53 static int default_phys_pager_getpages(vm_object_t object, vm_page_t *m,
54 int count, int *rbehind, int *rahead);
55 static int default_phys_pager_populate(vm_object_t object, vm_pindex_t pidx,
56 int fault_type, vm_prot_t max_prot, vm_pindex_t *first, vm_pindex_t *last);
57 static boolean_t default_phys_pager_haspage(vm_object_t object,
58 vm_pindex_t pindex, int *before, int *after);
59 const struct phys_pager_ops default_phys_pg_ops = {
60 .phys_pg_getpages = default_phys_pager_getpages,
61 .phys_pg_populate = default_phys_pager_populate,
62 .phys_pg_haspage = default_phys_pager_haspage,
63 .phys_pg_ctor = NULL,
64 .phys_pg_dtor = NULL,
65 };
66
67 static void
phys_pager_init(void)68 phys_pager_init(void)
69 {
70
71 TAILQ_INIT(&phys_pager_object_list);
72 mtx_init(&phys_pager_mtx, "phys_pager list", NULL, MTX_DEF);
73 }
74
75 vm_object_t
phys_pager_allocate(void * handle,const struct phys_pager_ops * ops,void * data,vm_ooffset_t size,vm_prot_t prot,vm_ooffset_t foff,struct ucred * cred)76 phys_pager_allocate(void *handle, const struct phys_pager_ops *ops, void *data,
77 vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t foff, struct ucred *cred)
78 {
79 vm_object_t object, object1;
80 vm_pindex_t pindex;
81 bool init;
82
83 /*
84 * Offset should be page aligned.
85 */
86 if (foff & PAGE_MASK)
87 return (NULL);
88
89 pindex = OFF_TO_IDX(foff + PAGE_MASK + size);
90 init = true;
91
92 if (handle != NULL) {
93 mtx_lock(&phys_pager_mtx);
94 /*
95 * Look up pager, creating as necessary.
96 */
97 object1 = NULL;
98 object = vm_pager_object_lookup(&phys_pager_object_list, handle);
99 if (object == NULL) {
100 /*
101 * Allocate object and associate it with the pager.
102 */
103 mtx_unlock(&phys_pager_mtx);
104 object1 = vm_object_allocate(OBJT_PHYS, pindex);
105 mtx_lock(&phys_pager_mtx);
106 object = vm_pager_object_lookup(&phys_pager_object_list,
107 handle);
108 if (object != NULL) {
109 /*
110 * We raced with other thread while
111 * allocating object.
112 */
113 if (pindex > object->size)
114 object->size = pindex;
115 init = false;
116 } else {
117 object = object1;
118 object1 = NULL;
119 object->handle = handle;
120 object->un_pager.phys.ops = ops;
121 object->un_pager.phys.data_ptr = data;
122 if (ops->phys_pg_populate != NULL)
123 vm_object_set_flag(object, OBJ_POPULATE);
124 TAILQ_INSERT_TAIL(&phys_pager_object_list,
125 object, pager_object_list);
126 }
127 } else {
128 if (pindex > object->size)
129 object->size = pindex;
130 }
131 mtx_unlock(&phys_pager_mtx);
132 vm_object_deallocate(object1);
133 } else {
134 object = vm_object_allocate(OBJT_PHYS, pindex);
135 object->un_pager.phys.ops = ops;
136 object->un_pager.phys.data_ptr = data;
137 if (ops->phys_pg_populate != NULL)
138 vm_object_set_flag(object, OBJ_POPULATE);
139 }
140 if (init && ops->phys_pg_ctor != NULL)
141 ops->phys_pg_ctor(object, prot, foff, cred);
142
143 return (object);
144 }
145
146 static vm_object_t
phys_pager_alloc(void * handle,vm_ooffset_t size,vm_prot_t prot,vm_ooffset_t foff,struct ucred * ucred)147 phys_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
148 vm_ooffset_t foff, struct ucred *ucred)
149 {
150 return (phys_pager_allocate(handle, &default_phys_pg_ops, NULL,
151 size, prot, foff, ucred));
152 }
153
154 static void
phys_pager_dealloc(vm_object_t object)155 phys_pager_dealloc(vm_object_t object)
156 {
157
158 if (object->handle != NULL) {
159 VM_OBJECT_WUNLOCK(object);
160 mtx_lock(&phys_pager_mtx);
161 TAILQ_REMOVE(&phys_pager_object_list, object, pager_object_list);
162 mtx_unlock(&phys_pager_mtx);
163 VM_OBJECT_WLOCK(object);
164 }
165 object->type = OBJT_DEAD;
166 if (object->un_pager.phys.ops->phys_pg_dtor != NULL)
167 object->un_pager.phys.ops->phys_pg_dtor(object);
168 object->handle = NULL;
169 }
170
171 /*
172 * Fill as many pages as vm_fault has allocated for us.
173 */
174 static int
default_phys_pager_getpages(vm_object_t object,vm_page_t * m,int count,int * rbehind,int * rahead)175 default_phys_pager_getpages(vm_object_t object, vm_page_t *m, int count,
176 int *rbehind, int *rahead)
177 {
178 int i;
179
180 for (i = 0; i < count; i++) {
181 if (vm_page_none_valid(m[i])) {
182 if ((m[i]->flags & PG_ZERO) == 0)
183 pmap_zero_page(m[i]);
184 vm_page_valid(m[i]);
185 }
186 KASSERT(vm_page_all_valid(m[i]),
187 ("phys_pager_getpages: partially valid page %p", m[i]));
188 KASSERT(m[i]->dirty == 0,
189 ("phys_pager_getpages: dirty page %p", m[i]));
190 }
191 if (rbehind)
192 *rbehind = 0;
193 if (rahead)
194 *rahead = 0;
195 return (VM_PAGER_OK);
196 }
197
198 static int
phys_pager_getpages(vm_object_t object,vm_page_t * m,int count,int * rbehind,int * rahead)199 phys_pager_getpages(vm_object_t object, vm_page_t *m, int count, int *rbehind,
200 int *rahead)
201 {
202 return (object->un_pager.phys.ops->phys_pg_getpages(object, m,
203 count, rbehind, rahead));
204 }
205
206 /*
207 * Implement a pretty aggressive clustered getpages strategy. Hint that
208 * everything in an entire 4MB window should be prefaulted at once.
209 *
210 * 4MB (1024 slots per page table page) is convenient for x86,
211 * but may not be for other arches.
212 */
213 #ifndef PHYSCLUSTER
214 #define PHYSCLUSTER 1024
215 #endif
216 static int phys_pager_cluster = PHYSCLUSTER;
217 SYSCTL_INT(_vm, OID_AUTO, phys_pager_cluster, CTLFLAG_RWTUN,
218 &phys_pager_cluster, 0,
219 "prefault window size for phys pager");
220
221 /*
222 * Max hint to vm_page_alloc() about the further allocation needs
223 * inside the phys_pager_populate() loop. The number of bits used to
224 * implement VM_ALLOC_COUNT() determines the hard limit on this value.
225 * That limit is currently 65535.
226 */
227 #define PHYSALLOC 16
228
229 static int
default_phys_pager_populate(vm_object_t object,vm_pindex_t pidx,int fault_type __unused,vm_prot_t max_prot __unused,vm_pindex_t * first,vm_pindex_t * last)230 default_phys_pager_populate(vm_object_t object, vm_pindex_t pidx,
231 int fault_type __unused, vm_prot_t max_prot __unused, vm_pindex_t *first,
232 vm_pindex_t *last)
233 {
234 struct pctrie_iter pages;
235 vm_page_t m;
236 vm_pindex_t base, end, i;
237 int ahead;
238
239 VM_OBJECT_ASSERT_WLOCKED(object);
240 base = rounddown(pidx, phys_pager_cluster);
241 end = base + phys_pager_cluster - 1;
242 if (end >= object->size)
243 end = object->size - 1;
244 if (*first > base)
245 base = *first;
246 if (end > *last)
247 end = *last;
248 *first = base;
249 *last = end;
250 vm_page_iter_init(&pages, object);
251
252 for (i = base; i <= end; i++) {
253 ahead = MIN(end - i, PHYSALLOC);
254 m = vm_page_grab_iter(object, &pages, i,
255 VM_ALLOC_NORMAL | VM_ALLOC_COUNT(ahead));
256 if (!vm_page_all_valid(m))
257 vm_page_zero_invalid(m, TRUE);
258 KASSERT(m->dirty == 0,
259 ("phys_pager_populate: dirty page %p", m));
260 }
261 return (VM_PAGER_OK);
262 }
263
264 static int
phys_pager_populate(vm_object_t object,vm_pindex_t pidx,int fault_type,vm_prot_t max_prot,vm_pindex_t * first,vm_pindex_t * last)265 phys_pager_populate(vm_object_t object, vm_pindex_t pidx, int fault_type,
266 vm_prot_t max_prot, vm_pindex_t *first, vm_pindex_t *last)
267 {
268 return (object->un_pager.phys.ops->phys_pg_populate(object, pidx,
269 fault_type, max_prot, first, last));
270 }
271
272 static void
phys_pager_putpages(vm_object_t object,vm_page_t * m,int count,int flags,int * rtvals)273 phys_pager_putpages(vm_object_t object, vm_page_t *m, int count, int flags,
274 int *rtvals)
275 {
276
277 panic("phys_pager_putpage called");
278 }
279
280 static boolean_t
default_phys_pager_haspage(vm_object_t object,vm_pindex_t pindex,int * before,int * after)281 default_phys_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before,
282 int *after)
283 {
284 vm_pindex_t base, end;
285
286 base = rounddown(pindex, phys_pager_cluster);
287 end = base + phys_pager_cluster - 1;
288 if (before != NULL)
289 *before = pindex - base;
290 if (after != NULL)
291 *after = end - pindex;
292 return (TRUE);
293 }
294
295 static boolean_t
phys_pager_haspage(vm_object_t object,vm_pindex_t pindex,int * before,int * after)296 phys_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before,
297 int *after)
298 {
299 return (object->un_pager.phys.ops->phys_pg_haspage(object, pindex,
300 before, after));
301 }
302
303 const struct pagerops physpagerops = {
304 .pgo_kvme_type = KVME_TYPE_PHYS,
305 .pgo_init = phys_pager_init,
306 .pgo_alloc = phys_pager_alloc,
307 .pgo_dealloc = phys_pager_dealloc,
308 .pgo_getpages = phys_pager_getpages,
309 .pgo_putpages = phys_pager_putpages,
310 .pgo_haspage = phys_pager_haspage,
311 .pgo_populate = phys_pager_populate,
312 };
313