1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2000,2003 Doug Rabson
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/param.h>
30 #include <sys/kernel.h>
31 #include <sys/kobj.h>
32 #include <sys/lock.h>
33 #include <sys/malloc.h>
34 #include <sys/mutex.h>
35 #include <sys/sysctl.h>
36 #ifndef TEST
37 #include <sys/systm.h>
38 #endif
39
40 #ifdef TEST
41 #include "usertest.h"
42 #endif
43
44 static MALLOC_DEFINE(M_KOBJ, "kobj", "Kernel object structures");
45
46 #ifdef KOBJ_STATS
47
48 u_int kobj_lookup_hits;
49 u_int kobj_lookup_misses;
50
51 SYSCTL_UINT(_kern, OID_AUTO, kobj_hits, CTLFLAG_RD,
52 &kobj_lookup_hits, 0, "");
53 SYSCTL_UINT(_kern, OID_AUTO, kobj_misses, CTLFLAG_RD,
54 &kobj_lookup_misses, 0, "");
55
56 #endif
57
58 static struct mtx kobj_mtx;
59 static int kobj_mutex_inited;
60 static int kobj_next_id = 1;
61
62 #define KOBJ_LOCK() mtx_lock(&kobj_mtx)
63 #define KOBJ_UNLOCK() mtx_unlock(&kobj_mtx)
64 #define KOBJ_ASSERT(what) mtx_assert(&kobj_mtx, what);
65
66 SYSCTL_INT(_kern, OID_AUTO, kobj_methodcount, CTLFLAG_RD,
67 &kobj_next_id, 0,
68 "Number of kernel object methods registered");
69
70 static void
kobj_init_mutex(void * arg)71 kobj_init_mutex(void *arg)
72 {
73 if (!kobj_mutex_inited) {
74 mtx_init(&kobj_mtx, "kobj", NULL, MTX_DEF);
75 kobj_mutex_inited = 1;
76 }
77 }
78
79 SYSINIT(kobj, SI_SUB_LOCK, SI_ORDER_ANY, kobj_init_mutex, NULL);
80
81 /*
82 * This method structure is used to initialise new caches. Since the
83 * desc pointer is NULL, it is guaranteed never to match any read
84 * descriptors.
85 */
86 static const struct kobj_method null_method = {
87 0, 0,
88 };
89
90 int
kobj_error_method(void)91 kobj_error_method(void)
92 {
93
94 return ENXIO;
95 }
96
97 static inline size_t
kobj_data_size_roundup(size_t size)98 kobj_data_size_roundup(size_t size)
99 {
100
101 return (roundup2((size), _Alignof(__max_align_t)));
102 }
103
104 static void
kobj_class_init_total_size(kobj_class_t cls)105 kobj_class_init_total_size(kobj_class_t cls)
106 {
107 kobj_class_t *bases;
108 size_t size;
109 int i;
110
111 MPASS(!cls->total_size_inited);
112 bases = cls->baseclasses;
113
114 size = kobj_data_size_roundup(cls->size);
115 if (bases != NULL) {
116 for (i = 0; bases[i] != NULL; i++) {
117 if (!bases[i]->total_size_inited)
118 kobj_class_init_total_size(bases[i]);
119 size += bases[i]->total_size;
120 }
121 }
122 cls->total_size_inited = true;
123 cls->total_size = size;
124 }
125
126 static void
kobj_class_compile_common(kobj_class_t cls,kobj_ops_t ops)127 kobj_class_compile_common(kobj_class_t cls, kobj_ops_t ops)
128 {
129 kobj_method_t *m;
130 int i;
131
132 /*
133 * Don't do anything if we are already compiled.
134 */
135 if (cls->ops)
136 return;
137
138 /*
139 * First register any methods which need it.
140 */
141 for (m = cls->methods; m->desc; m++) {
142 if (m->desc->id == 0)
143 m->desc->id = kobj_next_id++;
144 }
145
146 /*
147 * Then initialise the ops table.
148 */
149 for (i = 0; i < KOBJ_CACHE_SIZE; i++)
150 ops->cache[i] = &null_method;
151 ops->cls = cls;
152 cls->ops = ops;
153
154 /*
155 * Then compute total object data size.
156 */
157 if (!cls->total_size_inited)
158 kobj_class_init_total_size(cls);
159 }
160
161 static int
kobj_class_compile1(kobj_class_t cls,int mflags)162 kobj_class_compile1(kobj_class_t cls, int mflags)
163 {
164 kobj_ops_t ops;
165
166 KOBJ_ASSERT(MA_NOTOWNED);
167
168 ops = malloc(sizeof(struct kobj_ops), M_KOBJ, mflags);
169 if (ops == NULL)
170 return (ENOMEM);
171
172 /*
173 * We may have lost a race for kobj_class_compile here - check
174 * to make sure someone else hasn't already compiled this
175 * class.
176 */
177 KOBJ_LOCK();
178 if (cls->ops) {
179 KOBJ_UNLOCK();
180 free(ops, M_KOBJ);
181 return (0);
182 }
183 kobj_class_compile_common(cls, ops);
184 KOBJ_UNLOCK();
185 return (0);
186 }
187
188 void
kobj_class_compile(kobj_class_t cls)189 kobj_class_compile(kobj_class_t cls)
190 {
191 int error __diagused;
192
193 error = kobj_class_compile1(cls, M_WAITOK);
194 KASSERT(error == 0, ("kobj_class_compile1 returned %d", error));
195 }
196
197 void
kobj_class_compile_static(kobj_class_t cls,kobj_ops_t ops)198 kobj_class_compile_static(kobj_class_t cls, kobj_ops_t ops)
199 {
200
201 KASSERT(kobj_mutex_inited == 0,
202 ("%s: only supported during early cycles", __func__));
203
204 /*
205 * Increment refs to make sure that the ops table is not freed.
206 */
207 cls->refs++;
208 kobj_class_compile_common(cls, ops);
209 }
210
211 static kobj_method_t*
kobj_lookup_method_class(kobj_class_t cls,kobjop_desc_t desc)212 kobj_lookup_method_class(kobj_class_t cls, kobjop_desc_t desc)
213 {
214 kobj_method_t *methods = cls->methods;
215 kobj_method_t *ce;
216
217 for (ce = methods; ce && ce->desc; ce++) {
218 if (ce->desc == desc) {
219 return ce;
220 }
221 }
222
223 return NULL;
224 }
225
226 static kobj_method_t*
kobj_lookup_method_mi(kobj_class_t cls,kobjop_desc_t desc)227 kobj_lookup_method_mi(kobj_class_t cls,
228 kobjop_desc_t desc)
229 {
230 kobj_method_t *ce;
231 kobj_class_t *basep;
232
233 ce = kobj_lookup_method_class(cls, desc);
234 if (ce)
235 return ce;
236
237 basep = cls->baseclasses;
238 if (basep) {
239 for (; *basep; basep++) {
240 ce = kobj_lookup_method_mi(*basep, desc);
241 if (ce)
242 return ce;
243 }
244 }
245
246 return NULL;
247 }
248
249 kobj_method_t*
kobj_lookup_method(kobj_class_t cls,kobj_method_t ** cep,kobjop_desc_t desc)250 kobj_lookup_method(kobj_class_t cls,
251 kobj_method_t **cep,
252 kobjop_desc_t desc)
253 {
254 kobj_method_t *ce;
255
256 ce = kobj_lookup_method_mi(cls, desc);
257 if (!ce)
258 ce = &desc->deflt;
259 if (cep)
260 *cep = ce;
261 return ce;
262 }
263
264 void
kobj_class_free(kobj_class_t cls)265 kobj_class_free(kobj_class_t cls)
266 {
267 void* ops = NULL;
268
269 KOBJ_ASSERT(MA_NOTOWNED);
270 KOBJ_LOCK();
271
272 /*
273 * Protect against a race between kobj_create and
274 * kobj_delete.
275 */
276 if (cls->refs == 0) {
277 /*
278 * For now we don't do anything to unregister any methods
279 * which are no longer used.
280 */
281
282 /*
283 * Free memory and clean up.
284 */
285 ops = cls->ops;
286 cls->ops = NULL;
287 }
288
289 KOBJ_UNLOCK();
290
291 if (ops)
292 free(ops, M_KOBJ);
293 }
294
295 static void
kobj_init_common(kobj_t obj,kobj_class_t cls)296 kobj_init_common(kobj_t obj, kobj_class_t cls)
297 {
298
299 obj->ops = cls->ops;
300 cls->refs++;
301 }
302
303 static int
kobj_init1(kobj_t obj,kobj_class_t cls,int mflags)304 kobj_init1(kobj_t obj, kobj_class_t cls, int mflags)
305 {
306 int error;
307
308 KOBJ_LOCK();
309 while (cls->ops == NULL) {
310 /*
311 * kobj_class_compile doesn't want the lock held
312 * because of the call to malloc - we drop the lock
313 * and re-try.
314 */
315 KOBJ_UNLOCK();
316 error = kobj_class_compile1(cls, mflags);
317 if (error != 0)
318 return (error);
319 KOBJ_LOCK();
320 }
321 kobj_init_common(obj, cls);
322 KOBJ_UNLOCK();
323 return (0);
324 }
325
326 kobj_t
kobj_create(kobj_class_t cls,struct malloc_type * mtype,int mflags)327 kobj_create(kobj_class_t cls, struct malloc_type *mtype, int mflags)
328 {
329 kobj_t obj;
330
331 obj = malloc(cls->size, mtype, mflags | M_ZERO);
332 if (obj == NULL)
333 return (NULL);
334 if (kobj_init1(obj, cls, mflags) != 0) {
335 free(obj, mtype);
336 return (NULL);
337 }
338 return (obj);
339 }
340
341 void
kobj_init(kobj_t obj,kobj_class_t cls)342 kobj_init(kobj_t obj, kobj_class_t cls)
343 {
344 int error;
345
346 error = kobj_init1(obj, cls, M_WAITOK);
347 if (error != 0)
348 panic("kobj_init1 failed: error %d", error);
349 }
350
351 void
kobj_init_static(kobj_t obj,kobj_class_t cls)352 kobj_init_static(kobj_t obj, kobj_class_t cls)
353 {
354
355 KASSERT(cls->ops != NULL,
356 ("%s: class %p is not compiled", __func__, cls));
357 KASSERT(kobj_mutex_inited == 0,
358 ("%s: only supported during early cycles", __func__));
359
360 kobj_init_common(obj, cls);
361 }
362
363 void
kobj_delete(kobj_t obj,struct malloc_type * mtype)364 kobj_delete(kobj_t obj, struct malloc_type *mtype)
365 {
366 kobj_class_t cls = obj->ops->cls;
367 int refs;
368
369 /*
370 * Consider freeing the compiled method table for the class
371 * after its last instance is deleted. As an optimisation, we
372 * should defer this for a short while to avoid thrashing.
373 */
374 KOBJ_ASSERT(MA_NOTOWNED);
375 KOBJ_LOCK();
376 cls->refs--;
377 refs = cls->refs;
378 KOBJ_UNLOCK();
379
380 if (!refs)
381 kobj_class_free(cls);
382
383 obj->ops = NULL;
384 if (mtype)
385 free(obj, mtype);
386 }
387
388 static inline bool
kobj_get_instance_offset(kobj_class_t cls,kobj_class_t subclass,size_t * offs)389 kobj_get_instance_offset(kobj_class_t cls, kobj_class_t subclass, size_t *offs)
390 {
391 kobj_class_t *bases;
392 size_t tmp;
393 int i;
394
395 if (cls == subclass)
396 return (true);
397
398 bases = cls->baseclasses;
399 *offs += kobj_data_size_roundup(cls->size);
400
401 if (bases == NULL || bases[0] == NULL)
402 return (false);
403
404 /* Try most common cases (offset of direct subclass) first. */
405 tmp = *offs;
406 for (i = 0; bases[i] != NULL; i++) {
407 if (bases[i] == subclass) {
408 *offs = tmp;
409 return (true);
410 }
411 tmp += bases[i]->total_size;
412 }
413
414 /* Then do recursion for nested classes. */
415 for (i = 0; bases[i] != NULL; i++) {
416 if (kobj_get_instance_offset(bases[i], subclass, offs))
417 return (true);
418 }
419 return (false);
420 }
421
422 /*
423 * Get the data offset for the given class.
424 * layout is: [main | base0 | base1 | ... ]
425 */
426 size_t
kobj_instance_offset(kobj_class_t cls,kobj_class_t subclass)427 kobj_instance_offset(kobj_class_t cls, kobj_class_t subclass)
428 {
429 size_t offs;
430
431 if (cls == subclass)
432 return (0);
433
434 offs = 0;
435 if (!kobj_get_instance_offset(cls, subclass, &offs))
436 panic("%s: class %s not found in hierarchy of %s", __func__,
437 subclass->name, cls->name);
438 return (offs);
439 }
440
441 /*
442 * Get the total data size of this class and all its subclasses.
443 */
444 size_t
kobj_total_data_size(kobj_class_t cls)445 kobj_total_data_size(kobj_class_t cls)
446 {
447
448 MPASS(cls->total_size_inited);
449
450 return (cls->total_size);
451 }
452