1 /*- 2 * Copyright (c) 2000,2003 Doug Rabson 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 #include <sys/param.h> 31 #include <sys/kernel.h> 32 #include <sys/kobj.h> 33 #include <sys/lock.h> 34 #include <sys/malloc.h> 35 #include <sys/mutex.h> 36 #include <sys/sysctl.h> 37 #ifndef TEST 38 #include <sys/systm.h> 39 #endif 40 41 #ifdef TEST 42 #include "usertest.h" 43 #endif 44 45 static MALLOC_DEFINE(M_KOBJ, "kobj", "Kernel object structures"); 46 47 #ifdef KOBJ_STATS 48 49 u_int kobj_lookup_hits; 50 u_int kobj_lookup_misses; 51 52 SYSCTL_UINT(_kern, OID_AUTO, kobj_hits, CTLFLAG_RD, 53 &kobj_lookup_hits, 0, ""); 54 SYSCTL_UINT(_kern, OID_AUTO, kobj_misses, CTLFLAG_RD, 55 &kobj_lookup_misses, 0, ""); 56 57 #endif 58 59 static struct mtx kobj_mtx; 60 static int kobj_mutex_inited; 61 static int kobj_next_id = 1; 62 63 /* 64 * In the event that kobj_mtx has not been initialized yet, 65 * we will ignore it, and run without locks in order to support 66 * use of KOBJ before mutexes are available. This early in the boot 67 * process, everything is single threaded and so races should not 68 * happen. This is used to provide the PMAP layer on PowerPC, as well 69 * as board support. 70 */ 71 72 #define KOBJ_LOCK() if (kobj_mutex_inited) mtx_lock(&kobj_mtx); 73 #define KOBJ_UNLOCK() if (kobj_mutex_inited) mtx_unlock(&kobj_mtx); 74 #define KOBJ_ASSERT(what) if (kobj_mutex_inited) mtx_assert(&kobj_mtx,what); 75 76 SYSCTL_INT(_kern, OID_AUTO, kobj_methodcount, CTLFLAG_RD, 77 &kobj_next_id, 0, ""); 78 79 static void 80 kobj_init_mutex(void *arg) 81 { 82 if (!kobj_mutex_inited) { 83 mtx_init(&kobj_mtx, "kobj", NULL, MTX_DEF); 84 kobj_mutex_inited = 1; 85 } 86 } 87 88 SYSINIT(kobj, SI_SUB_LOCK, SI_ORDER_ANY, kobj_init_mutex, NULL); 89 90 /* 91 * This method structure is used to initialise new caches. Since the 92 * desc pointer is NULL, it is guaranteed never to match any read 93 * descriptors. 94 */ 95 static struct kobj_method null_method = { 96 0, 0, 97 }; 98 99 int 100 kobj_error_method(void) 101 { 102 103 return ENXIO; 104 } 105 106 static void 107 kobj_register_method(struct kobjop_desc *desc) 108 { 109 KOBJ_ASSERT(MA_OWNED); 110 111 if (desc->id == 0) { 112 desc->id = kobj_next_id++; 113 } 114 } 115 116 static void 117 kobj_unregister_method(struct kobjop_desc *desc) 118 { 119 } 120 121 static void 122 kobj_class_compile_common(kobj_class_t cls, kobj_ops_t ops) 123 { 124 kobj_method_t *m; 125 int i; 126 127 KOBJ_ASSERT(MA_OWNED); 128 129 /* 130 * Don't do anything if we are already compiled. 131 */ 132 if (cls->ops) 133 return; 134 135 /* 136 * First register any methods which need it. 137 */ 138 for (i = 0, m = cls->methods; m->desc; i++, m++) 139 kobj_register_method(m->desc); 140 141 /* 142 * Then initialise the ops table. 143 */ 144 for (i = 0; i < KOBJ_CACHE_SIZE; i++) 145 ops->cache[i] = &null_method; 146 ops->cls = cls; 147 cls->ops = ops; 148 } 149 150 void 151 kobj_class_compile(kobj_class_t cls) 152 { 153 kobj_ops_t ops; 154 155 KOBJ_ASSERT(MA_NOTOWNED); 156 157 /* 158 * Allocate space for the compiled ops table. 159 */ 160 ops = malloc(sizeof(struct kobj_ops), M_KOBJ, M_NOWAIT); 161 if (!ops) 162 panic("kobj_compile_methods: out of memory"); 163 164 KOBJ_LOCK(); 165 166 /* 167 * We may have lost a race for kobj_class_compile here - check 168 * to make sure someone else hasn't already compiled this 169 * class. 170 */ 171 if (cls->ops) { 172 KOBJ_UNLOCK(); 173 free(ops, M_KOBJ); 174 return; 175 } 176 177 kobj_class_compile_common(cls, ops); 178 KOBJ_UNLOCK(); 179 } 180 181 void 182 kobj_class_compile_static(kobj_class_t cls, kobj_ops_t ops) 183 { 184 185 KOBJ_ASSERT(MA_NOTOWNED); 186 187 /* 188 * Increment refs to make sure that the ops table is not freed. 189 */ 190 KOBJ_LOCK(); 191 192 cls->refs++; 193 kobj_class_compile_common(cls, ops); 194 195 KOBJ_UNLOCK(); 196 } 197 198 static kobj_method_t* 199 kobj_lookup_method_class(kobj_class_t cls, kobjop_desc_t desc) 200 { 201 kobj_method_t *methods = cls->methods; 202 kobj_method_t *ce; 203 204 for (ce = methods; ce && ce->desc; ce++) { 205 if (ce->desc == desc) { 206 return ce; 207 } 208 } 209 210 return NULL; 211 } 212 213 static kobj_method_t* 214 kobj_lookup_method_mi(kobj_class_t cls, 215 kobjop_desc_t desc) 216 { 217 kobj_method_t *ce; 218 kobj_class_t *basep; 219 220 ce = kobj_lookup_method_class(cls, desc); 221 if (ce) 222 return ce; 223 224 basep = cls->baseclasses; 225 if (basep) { 226 for (; *basep; basep++) { 227 ce = kobj_lookup_method_mi(*basep, desc); 228 if (ce) 229 return ce; 230 } 231 } 232 233 return NULL; 234 } 235 236 kobj_method_t* 237 kobj_lookup_method(kobj_class_t cls, 238 kobj_method_t **cep, 239 kobjop_desc_t desc) 240 { 241 kobj_method_t *ce; 242 243 #ifdef KOBJ_STATS 244 /* 245 * Correct for the 'hit' assumption in KOBJOPLOOKUP and record 246 * a 'miss'. 247 */ 248 kobj_lookup_hits--; 249 kobj_lookup_misses++; 250 #endif 251 252 ce = kobj_lookup_method_mi(cls, desc); 253 if (!ce) 254 ce = desc->deflt; 255 *cep = ce; 256 return ce; 257 } 258 259 void 260 kobj_class_free(kobj_class_t cls) 261 { 262 int i; 263 kobj_method_t *m; 264 void* ops = NULL; 265 266 KOBJ_ASSERT(MA_NOTOWNED); 267 KOBJ_LOCK(); 268 269 /* 270 * Protect against a race between kobj_create and 271 * kobj_delete. 272 */ 273 if (cls->refs == 0) { 274 /* 275 * Unregister any methods which are no longer used. 276 */ 277 for (i = 0, m = cls->methods; m->desc; i++, m++) 278 kobj_unregister_method(m->desc); 279 280 /* 281 * Free memory and clean up. 282 */ 283 ops = cls->ops; 284 cls->ops = NULL; 285 } 286 287 KOBJ_UNLOCK(); 288 289 if (ops) 290 free(ops, M_KOBJ); 291 } 292 293 kobj_t 294 kobj_create(kobj_class_t cls, 295 struct malloc_type *mtype, 296 int mflags) 297 { 298 kobj_t obj; 299 300 /* 301 * Allocate and initialise the new object. 302 */ 303 obj = malloc(cls->size, mtype, mflags | M_ZERO); 304 if (!obj) 305 return NULL; 306 kobj_init(obj, cls); 307 308 return obj; 309 } 310 311 void 312 kobj_init(kobj_t obj, kobj_class_t cls) 313 { 314 KOBJ_ASSERT(MA_NOTOWNED); 315 retry: 316 KOBJ_LOCK(); 317 318 /* 319 * Consider compiling the class' method table. 320 */ 321 if (!cls->ops) { 322 /* 323 * kobj_class_compile doesn't want the lock held 324 * because of the call to malloc - we drop the lock 325 * and re-try. 326 */ 327 KOBJ_UNLOCK(); 328 kobj_class_compile(cls); 329 goto retry; 330 } 331 332 obj->ops = cls->ops; 333 cls->refs++; 334 335 KOBJ_UNLOCK(); 336 } 337 338 void 339 kobj_delete(kobj_t obj, struct malloc_type *mtype) 340 { 341 kobj_class_t cls = obj->ops->cls; 342 int refs; 343 344 /* 345 * Consider freeing the compiled method table for the class 346 * after its last instance is deleted. As an optimisation, we 347 * should defer this for a short while to avoid thrashing. 348 */ 349 KOBJ_ASSERT(MA_NOTOWNED); 350 KOBJ_LOCK(); 351 cls->refs--; 352 refs = cls->refs; 353 KOBJ_UNLOCK(); 354 355 if (!refs) 356 kobj_class_free(cls); 357 358 obj->ops = NULL; 359 if (mtype) 360 free(obj, mtype); 361 } 362