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/rwlock.h>
37 #include <sys/sysctl.h>
38 #include <sys/user.h>
39
40 #include <vm/vm.h>
41 #include <vm/vm_param.h>
42 #include <vm/vm_object.h>
43 #include <vm/vm_page.h>
44 #include <vm/vm_pageout.h>
45 #include <vm/vm_pager.h>
46
47 /* list of phys pager objects */
48 static struct pagerlst phys_pager_object_list;
49 /* protect access to phys_pager_object_list */
50 static struct mtx phys_pager_mtx;
51
52 static int default_phys_pager_getpages(vm_object_t object, vm_page_t *m,
53 int count, int *rbehind, int *rahead);
54 static int default_phys_pager_populate(vm_object_t object, vm_pindex_t pidx,
55 int fault_type, vm_prot_t max_prot, vm_pindex_t *first, vm_pindex_t *last);
56 static boolean_t default_phys_pager_haspage(vm_object_t object,
57 vm_pindex_t pindex, int *before, int *after);
58 const struct phys_pager_ops default_phys_pg_ops = {
59 .phys_pg_getpages = default_phys_pager_getpages,
60 .phys_pg_populate = default_phys_pager_populate,
61 .phys_pg_haspage = default_phys_pager_haspage,
62 .phys_pg_ctor = NULL,
63 .phys_pg_dtor = NULL,
64 };
65
66 static void
phys_pager_init(void)67 phys_pager_init(void)
68 {
69
70 TAILQ_INIT(&phys_pager_object_list);
71 mtx_init(&phys_pager_mtx, "phys_pager list", NULL, MTX_DEF);
72 }
73
74 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)75 phys_pager_allocate(void *handle, const struct phys_pager_ops *ops, void *data,
76 vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t foff, struct ucred *cred)
77 {
78 vm_object_t object, object1;
79 vm_pindex_t pindex;
80 bool init;
81
82 /*
83 * Offset should be page aligned.
84 */
85 if (foff & PAGE_MASK)
86 return (NULL);
87
88 pindex = OFF_TO_IDX(foff + PAGE_MASK + size);
89 init = true;
90
91 if (handle != NULL) {
92 mtx_lock(&phys_pager_mtx);
93 /*
94 * Look up pager, creating as necessary.
95 */
96 object1 = NULL;
97 object = vm_pager_object_lookup(&phys_pager_object_list, handle);
98 if (object == NULL) {
99 /*
100 * Allocate object and associate it with the pager.
101 */
102 mtx_unlock(&phys_pager_mtx);
103 object1 = vm_object_allocate(OBJT_PHYS, pindex);
104 mtx_lock(&phys_pager_mtx);
105 object = vm_pager_object_lookup(&phys_pager_object_list,
106 handle);
107 if (object != NULL) {
108 /*
109 * We raced with other thread while
110 * allocating object.
111 */
112 if (pindex > object->size)
113 object->size = pindex;
114 init = false;
115 } else {
116 object = object1;
117 object1 = NULL;
118 object->handle = handle;
119 object->un_pager.phys.ops = ops;
120 object->un_pager.phys.data_ptr = data;
121 if (ops->phys_pg_populate != NULL)
122 vm_object_set_flag(object, OBJ_POPULATE);
123 TAILQ_INSERT_TAIL(&phys_pager_object_list,
124 object, pager_object_list);
125 }
126 } else {
127 if (pindex > object->size)
128 object->size = pindex;
129 }
130 mtx_unlock(&phys_pager_mtx);
131 vm_object_deallocate(object1);
132 } else {
133 object = vm_object_allocate(OBJT_PHYS, pindex);
134 object->un_pager.phys.ops = ops;
135 object->un_pager.phys.data_ptr = data;
136 if (ops->phys_pg_populate != NULL)
137 vm_object_set_flag(object, OBJ_POPULATE);
138 }
139 if (init && ops->phys_pg_ctor != NULL)
140 ops->phys_pg_ctor(object, prot, foff, cred);
141
142 return (object);
143 }
144
145 static vm_object_t
phys_pager_alloc(void * handle,vm_ooffset_t size,vm_prot_t prot,vm_ooffset_t foff,struct ucred * ucred)146 phys_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
147 vm_ooffset_t foff, struct ucred *ucred)
148 {
149 return (phys_pager_allocate(handle, &default_phys_pg_ops, NULL,
150 size, prot, foff, ucred));
151 }
152
153 static void
phys_pager_dealloc(vm_object_t object)154 phys_pager_dealloc(vm_object_t object)
155 {
156
157 if (object->handle != NULL) {
158 VM_OBJECT_WUNLOCK(object);
159 mtx_lock(&phys_pager_mtx);
160 TAILQ_REMOVE(&phys_pager_object_list, object, pager_object_list);
161 mtx_unlock(&phys_pager_mtx);
162 VM_OBJECT_WLOCK(object);
163 }
164 object->type = OBJT_DEAD;
165 if (object->un_pager.phys.ops->phys_pg_dtor != NULL)
166 object->un_pager.phys.ops->phys_pg_dtor(object);
167 object->handle = NULL;
168 }
169
170 /*
171 * Fill as many pages as vm_fault has allocated for us.
172 */
173 static int
default_phys_pager_getpages(vm_object_t object,vm_page_t * m,int count,int * rbehind,int * rahead)174 default_phys_pager_getpages(vm_object_t object, vm_page_t *m, int count,
175 int *rbehind, int *rahead)
176 {
177 int i;
178
179 for (i = 0; i < count; i++) {
180 if (vm_page_none_valid(m[i])) {
181 if ((m[i]->flags & PG_ZERO) == 0)
182 pmap_zero_page(m[i]);
183 vm_page_valid(m[i]);
184 }
185 KASSERT(vm_page_all_valid(m[i]),
186 ("phys_pager_getpages: partially valid page %p", m[i]));
187 KASSERT(m[i]->dirty == 0,
188 ("phys_pager_getpages: dirty page %p", m[i]));
189 }
190 if (rbehind)
191 *rbehind = 0;
192 if (rahead)
193 *rahead = 0;
194 return (VM_PAGER_OK);
195 }
196
197 static int
phys_pager_getpages(vm_object_t object,vm_page_t * m,int count,int * rbehind,int * rahead)198 phys_pager_getpages(vm_object_t object, vm_page_t *m, int count, int *rbehind,
199 int *rahead)
200 {
201 return (object->un_pager.phys.ops->phys_pg_getpages(object, m,
202 count, rbehind, rahead));
203 }
204
205 /*
206 * Implement a pretty aggressive clustered getpages strategy. Hint that
207 * everything in an entire 4MB window should be prefaulted at once.
208 *
209 * 4MB (1024 slots per page table page) is convenient for x86,
210 * but may not be for other arches.
211 */
212 #ifndef PHYSCLUSTER
213 #define PHYSCLUSTER 1024
214 #endif
215 static int phys_pager_cluster = PHYSCLUSTER;
216 SYSCTL_INT(_vm, OID_AUTO, phys_pager_cluster, CTLFLAG_RWTUN,
217 &phys_pager_cluster, 0,
218 "prefault window size for phys pager");
219
220 /*
221 * Max hint to vm_page_alloc() about the further allocation needs
222 * inside the phys_pager_populate() loop. The number of bits used to
223 * implement VM_ALLOC_COUNT() determines the hard limit on this value.
224 * That limit is currently 65535.
225 */
226 #define PHYSALLOC 16
227
228 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)229 default_phys_pager_populate(vm_object_t object, vm_pindex_t pidx,
230 int fault_type __unused, vm_prot_t max_prot __unused, vm_pindex_t *first,
231 vm_pindex_t *last)
232 {
233 vm_page_t m;
234 vm_pindex_t base, end, i;
235 int ahead;
236
237 base = rounddown(pidx, phys_pager_cluster);
238 end = base + phys_pager_cluster - 1;
239 if (end >= object->size)
240 end = object->size - 1;
241 if (*first > base)
242 base = *first;
243 if (end > *last)
244 end = *last;
245 *first = base;
246 *last = end;
247
248 for (i = base; i <= end; i++) {
249 ahead = MIN(end - i, PHYSALLOC);
250 m = vm_page_grab(object, i,
251 VM_ALLOC_NORMAL | VM_ALLOC_COUNT(ahead));
252 if (!vm_page_all_valid(m))
253 vm_page_zero_invalid(m, TRUE);
254 KASSERT(m->dirty == 0,
255 ("phys_pager_populate: dirty page %p", m));
256 }
257 return (VM_PAGER_OK);
258 }
259
260 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)261 phys_pager_populate(vm_object_t object, vm_pindex_t pidx, int fault_type,
262 vm_prot_t max_prot, vm_pindex_t *first, vm_pindex_t *last)
263 {
264 return (object->un_pager.phys.ops->phys_pg_populate(object, pidx,
265 fault_type, max_prot, first, last));
266 }
267
268 static void
phys_pager_putpages(vm_object_t object,vm_page_t * m,int count,int flags,int * rtvals)269 phys_pager_putpages(vm_object_t object, vm_page_t *m, int count, int flags,
270 int *rtvals)
271 {
272
273 panic("phys_pager_putpage called");
274 }
275
276 static boolean_t
default_phys_pager_haspage(vm_object_t object,vm_pindex_t pindex,int * before,int * after)277 default_phys_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before,
278 int *after)
279 {
280 vm_pindex_t base, end;
281
282 base = rounddown(pindex, phys_pager_cluster);
283 end = base + phys_pager_cluster - 1;
284 if (before != NULL)
285 *before = pindex - base;
286 if (after != NULL)
287 *after = end - pindex;
288 return (TRUE);
289 }
290
291 static boolean_t
phys_pager_haspage(vm_object_t object,vm_pindex_t pindex,int * before,int * after)292 phys_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before,
293 int *after)
294 {
295 return (object->un_pager.phys.ops->phys_pg_haspage(object, pindex,
296 before, after));
297 }
298
299 const struct pagerops physpagerops = {
300 .pgo_kvme_type = KVME_TYPE_PHYS,
301 .pgo_init = phys_pager_init,
302 .pgo_alloc = phys_pager_alloc,
303 .pgo_dealloc = phys_pager_dealloc,
304 .pgo_getpages = phys_pager_getpages,
305 .pgo_putpages = phys_pager_putpages,
306 .pgo_haspage = phys_pager_haspage,
307 .pgo_populate = phys_pager_populate,
308 };
309