1 /* 2 * Copyright 1998 Massachusetts Institute of Technology 3 * 4 * Permission to use, copy, modify, and distribute this software and 5 * its documentation for any purpose and without fee is hereby 6 * granted, provided that both the above copyright notice and this 7 * permission notice appear in all copies, that both the above 8 * copyright notice and this permission notice appear in all 9 * supporting documentation, and that the name of M.I.T. not be used 10 * in advertising or publicity pertaining to distribution of the 11 * software without specific, written prior permission. M.I.T. makes 12 * no representations about the suitability of this software for any 13 * purpose. It is provided "as is" without express or implied 14 * warranty. 15 * 16 * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''. M.I.T. DISCLAIMS 17 * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE, 18 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT 20 * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF 23 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 25 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 26 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * $FreeBSD: src/sys/kern/subr_rman.c,v 1.10.2.1 2001/06/05 08:06:08 imp Exp $ 30 * $DragonFly: src/sys/kern/subr_rman.c,v 1.11 2006/12/23 00:35:04 swildner Exp $ 31 */ 32 33 /* 34 * The kernel resource manager. This code is responsible for keeping track 35 * of hardware resources which are apportioned out to various drivers. 36 * It does not actually assign those resources, and it is not expected 37 * that end-device drivers will call into this code directly. Rather, 38 * the code which implements the buses that those devices are attached to, 39 * and the code which manages CPU resources, will call this code, and the 40 * end-device drivers will make upcalls to that code to actually perform 41 * the allocation. 42 * 43 * There are two sorts of resources managed by this code. The first is 44 * the more familiar array (RMAN_ARRAY) type; resources in this class 45 * consist of a sequence of individually-allocatable objects which have 46 * been numbered in some well-defined order. Most of the resources 47 * are of this type, as it is the most familiar. The second type is 48 * called a gauge (RMAN_GAUGE), and models fungible resources (i.e., 49 * resources in which each instance is indistinguishable from every 50 * other instance). The principal anticipated application of gauges 51 * is in the context of power consumption, where a bus may have a specific 52 * power budget which all attached devices share. RMAN_GAUGE is not 53 * implemented yet. 54 * 55 * For array resources, we make one simplifying assumption: two clients 56 * sharing the same resource must use the same range of indices. That 57 * is to say, sharing of overlapping-but-not-identical regions is not 58 * permitted. 59 */ 60 61 #include <sys/param.h> 62 #include <sys/systm.h> 63 #include <sys/kernel.h> 64 #include <sys/lock.h> 65 #include <sys/malloc.h> 66 #include <sys/bus.h> /* XXX debugging */ 67 #include <sys/rman.h> 68 69 static MALLOC_DEFINE(M_RMAN, "rman", "Resource manager"); 70 71 struct rman_head rman_head; 72 static struct lwkt_token rman_tok; /* mutex to protect rman_head */ 73 static int int_rman_activate_resource(struct rman *rm, struct resource *r, 74 struct resource **whohas); 75 static int int_rman_deactivate_resource(struct resource *r); 76 static int int_rman_release_resource(struct rman *rm, struct resource *r); 77 78 #define CIRCLEQ_TERMCOND(var, head) (var == (void *)&(head)) 79 80 int 81 rman_init(struct rman *rm) 82 { 83 static int once; 84 lwkt_tokref ilock; 85 86 if (once == 0) { 87 once = 1; 88 TAILQ_INIT(&rman_head); 89 lwkt_token_init(&rman_tok); 90 } 91 92 if (rm->rm_type == RMAN_UNINIT) 93 panic("rman_init"); 94 if (rm->rm_type == RMAN_GAUGE) 95 panic("implement RMAN_GAUGE"); 96 97 CIRCLEQ_INIT(&rm->rm_list); 98 rm->rm_slock = kmalloc(sizeof *rm->rm_slock, M_RMAN, M_NOWAIT); 99 if (rm->rm_slock == NULL) 100 return ENOMEM; 101 lwkt_token_init(rm->rm_slock); 102 103 lwkt_gettoken(&ilock, &rman_tok); 104 TAILQ_INSERT_TAIL(&rman_head, rm, rm_link); 105 lwkt_reltoken(&ilock); 106 return 0; 107 } 108 109 /* 110 * NB: this interface is not robust against programming errors which 111 * add multiple copies of the same region. 112 */ 113 int 114 rman_manage_region(struct rman *rm, u_long start, u_long end) 115 { 116 struct resource *r, *s; 117 lwkt_tokref ilock; 118 119 r = kmalloc(sizeof *r, M_RMAN, M_NOWAIT); 120 if (r == 0) 121 return ENOMEM; 122 bzero(r, sizeof *r); 123 r->r_sharehead = 0; 124 r->r_start = start; 125 r->r_end = end; 126 r->r_flags = 0; 127 r->r_dev = 0; 128 r->r_rm = rm; 129 130 lwkt_gettoken(&ilock, rm->rm_slock); 131 for (s = CIRCLEQ_FIRST(&rm->rm_list); 132 !CIRCLEQ_TERMCOND(s, rm->rm_list) && s->r_end < r->r_start; 133 s = CIRCLEQ_NEXT(s, r_link)) 134 ; 135 136 if (CIRCLEQ_TERMCOND(s, rm->rm_list)) { 137 CIRCLEQ_INSERT_TAIL(&rm->rm_list, r, r_link); 138 } else { 139 CIRCLEQ_INSERT_BEFORE(&rm->rm_list, s, r, r_link); 140 } 141 142 lwkt_reltoken(&ilock); 143 return 0; 144 } 145 146 int 147 rman_fini(struct rman *rm) 148 { 149 struct resource *r; 150 lwkt_tokref ilock; 151 152 lwkt_gettoken(&ilock, rm->rm_slock); 153 CIRCLEQ_FOREACH(r, &rm->rm_list, r_link) { 154 if (r->r_flags & RF_ALLOCATED) { 155 lwkt_reltoken(&ilock); 156 return EBUSY; 157 } 158 } 159 160 /* 161 * There really should only be one of these if we are in this 162 * state and the code is working properly, but it can't hurt. 163 */ 164 while (!CIRCLEQ_EMPTY(&rm->rm_list)) { 165 r = CIRCLEQ_FIRST(&rm->rm_list); 166 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link); 167 kfree(r, M_RMAN); 168 } 169 lwkt_reltoken(&ilock); 170 /* XXX what's the point of this if we are going to free the struct? */ 171 lwkt_gettoken(&ilock, &rman_tok); 172 TAILQ_REMOVE(&rman_head, rm, rm_link); 173 lwkt_reltoken(&ilock); 174 kfree(rm->rm_slock, M_RMAN); 175 176 return 0; 177 } 178 179 struct resource * 180 rman_reserve_resource(struct rman *rm, u_long start, u_long end, u_long count, 181 u_int flags, struct device *dev) 182 { 183 u_int want_activate; 184 struct resource *r, *s, *rv; 185 u_long rstart, rend; 186 lwkt_tokref ilock; 187 188 rv = 0; 189 190 #ifdef RMAN_DEBUG 191 kprintf("rman_reserve_resource: <%s> request: [%#lx, %#lx], length " 192 "%#lx, flags %u, device %s%d\n", rm->rm_descr, start, end, 193 count, flags, device_get_name(dev), device_get_unit(dev)); 194 #endif /* RMAN_DEBUG */ 195 want_activate = (flags & RF_ACTIVE); 196 flags &= ~RF_ACTIVE; 197 198 lwkt_gettoken(&ilock, rm->rm_slock); 199 200 for (r = CIRCLEQ_FIRST(&rm->rm_list); 201 !CIRCLEQ_TERMCOND(r, rm->rm_list) && r->r_end < start; 202 r = CIRCLEQ_NEXT(r, r_link)) 203 ; 204 205 if (CIRCLEQ_TERMCOND(r, rm->rm_list)) { 206 #ifdef RMAN_DEBUG 207 kprintf("could not find a region\n"); 208 #endif 209 goto out; 210 } 211 212 /* 213 * First try to find an acceptable totally-unshared region. 214 */ 215 for (s = r; !CIRCLEQ_TERMCOND(s, rm->rm_list); 216 s = CIRCLEQ_NEXT(s, r_link)) { 217 #ifdef RMAN_DEBUG 218 kprintf("considering [%#lx, %#lx]\n", s->r_start, s->r_end); 219 #endif /* RMAN_DEBUG */ 220 if (s->r_start > end) { 221 #ifdef RMAN_DEBUG 222 kprintf("s->r_start (%#lx) > end (%#lx)\n", s->r_start, end); 223 #endif /* RMAN_DEBUG */ 224 break; 225 } 226 if (s->r_flags & RF_ALLOCATED) { 227 #ifdef RMAN_DEBUG 228 kprintf("region is allocated\n"); 229 #endif /* RMAN_DEBUG */ 230 continue; 231 } 232 rstart = max(s->r_start, start); 233 rstart = (rstart + ((1ul << RF_ALIGNMENT(flags))) - 1) & 234 ~((1ul << RF_ALIGNMENT(flags)) - 1); 235 rend = min(s->r_end, max(start + count, end)); 236 #ifdef RMAN_DEBUG 237 kprintf("truncated region: [%#lx, %#lx]; size %#lx (requested %#lx)\n", 238 rstart, rend, (rend - rstart + 1), count); 239 #endif /* RMAN_DEBUG */ 240 241 if ((rend - rstart + 1) >= count) { 242 #ifdef RMAN_DEBUG 243 kprintf("candidate region: [%#lx, %#lx], size %#lx\n", 244 rend, rstart, (rend - rstart + 1)); 245 #endif /* RMAN_DEBUG */ 246 if ((s->r_end - s->r_start + 1) == count) { 247 #ifdef RMAN_DEBUG 248 kprintf("candidate region is entire chunk\n"); 249 #endif /* RMAN_DEBUG */ 250 rv = s; 251 rv->r_flags |= RF_ALLOCATED | flags; 252 rv->r_dev = dev; 253 goto out; 254 } 255 256 /* 257 * If s->r_start < rstart and 258 * s->r_end > rstart + count - 1, then 259 * we need to split the region into three pieces 260 * (the middle one will get returned to the user). 261 * Otherwise, we are allocating at either the 262 * beginning or the end of s, so we only need to 263 * split it in two. The first case requires 264 * two new allocations; the second requires but one. 265 */ 266 rv = kmalloc(sizeof *rv, M_RMAN, M_NOWAIT); 267 if (rv == 0) 268 goto out; 269 bzero(rv, sizeof *rv); 270 rv->r_start = rstart; 271 rv->r_end = rstart + count - 1; 272 rv->r_flags = flags | RF_ALLOCATED; 273 rv->r_dev = dev; 274 rv->r_sharehead = 0; 275 rv->r_rm = rm; 276 277 if (s->r_start < rv->r_start && s->r_end > rv->r_end) { 278 #ifdef RMAN_DEBUG 279 kprintf("splitting region in three parts: " 280 "[%#lx, %#lx]; [%#lx, %#lx]; [%#lx, %#lx]\n", 281 s->r_start, rv->r_start - 1, 282 rv->r_start, rv->r_end, 283 rv->r_end + 1, s->r_end); 284 #endif /* RMAN_DEBUG */ 285 /* 286 * We are allocating in the middle. 287 */ 288 r = kmalloc(sizeof *r, M_RMAN, M_NOWAIT); 289 if (r == 0) { 290 kfree(rv, M_RMAN); 291 rv = 0; 292 goto out; 293 } 294 bzero(r, sizeof *r); 295 r->r_start = rv->r_end + 1; 296 r->r_end = s->r_end; 297 r->r_flags = s->r_flags; 298 r->r_dev = 0; 299 r->r_sharehead = 0; 300 r->r_rm = rm; 301 s->r_end = rv->r_start - 1; 302 CIRCLEQ_INSERT_AFTER(&rm->rm_list, s, rv, 303 r_link); 304 CIRCLEQ_INSERT_AFTER(&rm->rm_list, rv, r, 305 r_link); 306 } else if (s->r_start == rv->r_start) { 307 #ifdef RMAN_DEBUG 308 kprintf("allocating from the beginning\n"); 309 #endif /* RMAN_DEBUG */ 310 /* 311 * We are allocating at the beginning. 312 */ 313 s->r_start = rv->r_end + 1; 314 CIRCLEQ_INSERT_BEFORE(&rm->rm_list, s, rv, 315 r_link); 316 } else { 317 #ifdef RMAN_DEBUG 318 kprintf("allocating at the end\n"); 319 #endif /* RMAN_DEBUG */ 320 /* 321 * We are allocating at the end. 322 */ 323 s->r_end = rv->r_start - 1; 324 CIRCLEQ_INSERT_AFTER(&rm->rm_list, s, rv, 325 r_link); 326 } 327 goto out; 328 } 329 } 330 331 /* 332 * Now find an acceptable shared region, if the client's requirements 333 * allow sharing. By our implementation restriction, a candidate 334 * region must match exactly by both size and sharing type in order 335 * to be considered compatible with the client's request. (The 336 * former restriction could probably be lifted without too much 337 * additional work, but this does not seem warranted.) 338 */ 339 #ifdef RMAN_DEBUG 340 kprintf("no unshared regions found\n"); 341 #endif /* RMAN_DEBUG */ 342 if ((flags & (RF_SHAREABLE | RF_TIMESHARE)) == 0) 343 goto out; 344 345 for (s = r; !CIRCLEQ_TERMCOND(s, rm->rm_list); 346 s = CIRCLEQ_NEXT(s, r_link)) { 347 if (s->r_start > end) 348 break; 349 if ((s->r_flags & flags) != flags) 350 continue; 351 rstart = max(s->r_start, start); 352 rend = min(s->r_end, max(start + count, end)); 353 if (s->r_start >= start && s->r_end <= end 354 && (s->r_end - s->r_start + 1) == count) { 355 rv = kmalloc(sizeof *rv, M_RMAN, M_NOWAIT); 356 if (rv == 0) 357 goto out; 358 bzero(rv, sizeof *rv); 359 rv->r_start = s->r_start; 360 rv->r_end = s->r_end; 361 rv->r_flags = s->r_flags & 362 (RF_ALLOCATED | RF_SHAREABLE | RF_TIMESHARE); 363 rv->r_dev = dev; 364 rv->r_rm = rm; 365 if (s->r_sharehead == 0) { 366 s->r_sharehead = kmalloc(sizeof *s->r_sharehead, 367 M_RMAN, M_NOWAIT); 368 if (s->r_sharehead == 0) { 369 kfree(rv, M_RMAN); 370 rv = 0; 371 goto out; 372 } 373 bzero(s->r_sharehead, sizeof *s->r_sharehead); 374 LIST_INIT(s->r_sharehead); 375 LIST_INSERT_HEAD(s->r_sharehead, s, 376 r_sharelink); 377 s->r_flags |= RF_FIRSTSHARE; 378 } 379 rv->r_sharehead = s->r_sharehead; 380 LIST_INSERT_HEAD(s->r_sharehead, rv, r_sharelink); 381 goto out; 382 } 383 } 384 385 /* 386 * We couldn't find anything. 387 */ 388 out: 389 /* 390 * If the user specified RF_ACTIVE in the initial flags, 391 * which is reflected in `want_activate', we attempt to atomically 392 * activate the resource. If this fails, we release the resource 393 * and indicate overall failure. (This behavior probably doesn't 394 * make sense for RF_TIMESHARE-type resources.) 395 */ 396 if (rv && want_activate) { 397 struct resource *whohas; 398 if (int_rman_activate_resource(rm, rv, &whohas)) { 399 int_rman_release_resource(rm, rv); 400 rv = 0; 401 } 402 } 403 lwkt_reltoken(&ilock); 404 return (rv); 405 } 406 407 static int 408 int_rman_activate_resource(struct rman *rm, struct resource *r, 409 struct resource **whohas) 410 { 411 struct resource *s; 412 int ok; 413 414 /* 415 * If we are not timesharing, then there is nothing much to do. 416 * If we already have the resource, then there is nothing at all to do. 417 * If we are not on a sharing list with anybody else, then there is 418 * little to do. 419 */ 420 if ((r->r_flags & RF_TIMESHARE) == 0 421 || (r->r_flags & RF_ACTIVE) != 0 422 || r->r_sharehead == 0) { 423 r->r_flags |= RF_ACTIVE; 424 return 0; 425 } 426 427 ok = 1; 428 for (s = LIST_FIRST(r->r_sharehead); s && ok; 429 s = LIST_NEXT(s, r_sharelink)) { 430 if ((s->r_flags & RF_ACTIVE) != 0) { 431 ok = 0; 432 *whohas = s; 433 } 434 } 435 if (ok) { 436 r->r_flags |= RF_ACTIVE; 437 return 0; 438 } 439 return EBUSY; 440 } 441 442 int 443 rman_activate_resource(struct resource *r) 444 { 445 int rv; 446 struct resource *whohas; 447 lwkt_tokref ilock; 448 struct rman *rm; 449 450 rm = r->r_rm; 451 lwkt_gettoken(&ilock, rm->rm_slock); 452 rv = int_rman_activate_resource(rm, r, &whohas); 453 lwkt_reltoken(&ilock); 454 return rv; 455 } 456 457 #if 0 458 459 /* XXX */ 460 int 461 rman_await_resource(struct resource *r, lwkt_tokref_t ilock, int slpflags, int timo) 462 { 463 int rv; 464 struct resource *whohas; 465 struct rman *rm; 466 467 rm = r->r_rm; 468 for (;;) { 469 lwkt_gettoken(ilock, rm->rm_slock); 470 rv = int_rman_activate_resource(rm, r, &whohas); 471 if (rv != EBUSY) 472 return (rv); /* returns with ilock held */ 473 474 if (r->r_sharehead == 0) 475 panic("rman_await_resource"); 476 /* 477 * A critical section will hopefully will prevent a race 478 * between lwkt_reltoken and tsleep where a process 479 * could conceivably get in and release the resource 480 * before we have a chance to sleep on it. YYY 481 */ 482 crit_enter(); 483 whohas->r_flags |= RF_WANTED; 484 rv = tsleep(r->r_sharehead, slpflags, "rmwait", timo); 485 if (rv) { 486 lwkt_reltoken(ilock); 487 crit_exit(); 488 return rv; 489 } 490 crit_exit(); 491 } 492 } 493 494 #endif 495 496 static int 497 int_rman_deactivate_resource(struct resource *r) 498 { 499 struct rman *rm; 500 501 rm = r->r_rm; 502 r->r_flags &= ~RF_ACTIVE; 503 if (r->r_flags & RF_WANTED) { 504 r->r_flags &= ~RF_WANTED; 505 wakeup(r->r_sharehead); 506 } 507 return 0; 508 } 509 510 int 511 rman_deactivate_resource(struct resource *r) 512 { 513 lwkt_tokref ilock; 514 struct rman *rm; 515 516 rm = r->r_rm; 517 lwkt_gettoken(&ilock, rm->rm_slock); 518 int_rman_deactivate_resource(r); 519 lwkt_reltoken(&ilock); 520 return 0; 521 } 522 523 static int 524 int_rman_release_resource(struct rman *rm, struct resource *r) 525 { 526 struct resource *s, *t; 527 528 if (r->r_flags & RF_ACTIVE) 529 int_rman_deactivate_resource(r); 530 531 /* 532 * Check for a sharing list first. If there is one, then we don't 533 * have to think as hard. 534 */ 535 if (r->r_sharehead) { 536 /* 537 * If a sharing list exists, then we know there are at 538 * least two sharers. 539 * 540 * If we are in the main circleq, appoint someone else. 541 */ 542 LIST_REMOVE(r, r_sharelink); 543 s = LIST_FIRST(r->r_sharehead); 544 if (r->r_flags & RF_FIRSTSHARE) { 545 s->r_flags |= RF_FIRSTSHARE; 546 CIRCLEQ_INSERT_BEFORE(&rm->rm_list, r, s, r_link); 547 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link); 548 } 549 550 /* 551 * Make sure that the sharing list goes away completely 552 * if the resource is no longer being shared at all. 553 */ 554 if (LIST_NEXT(s, r_sharelink) == 0) { 555 kfree(s->r_sharehead, M_RMAN); 556 s->r_sharehead = 0; 557 s->r_flags &= ~RF_FIRSTSHARE; 558 } 559 goto out; 560 } 561 562 /* 563 * Look at the adjacent resources in the list and see if our 564 * segment can be merged with any of them. 565 */ 566 s = CIRCLEQ_PREV(r, r_link); 567 t = CIRCLEQ_NEXT(r, r_link); 568 569 if (s != (void *)&rm->rm_list && (s->r_flags & RF_ALLOCATED) == 0 570 && t != (void *)&rm->rm_list && (t->r_flags & RF_ALLOCATED) == 0) { 571 /* 572 * Merge all three segments. 573 */ 574 s->r_end = t->r_end; 575 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link); 576 CIRCLEQ_REMOVE(&rm->rm_list, t, r_link); 577 kfree(t, M_RMAN); 578 } else if (s != (void *)&rm->rm_list 579 && (s->r_flags & RF_ALLOCATED) == 0) { 580 /* 581 * Merge previous segment with ours. 582 */ 583 s->r_end = r->r_end; 584 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link); 585 } else if (t != (void *)&rm->rm_list 586 && (t->r_flags & RF_ALLOCATED) == 0) { 587 /* 588 * Merge next segment with ours. 589 */ 590 t->r_start = r->r_start; 591 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link); 592 } else { 593 /* 594 * At this point, we know there is nothing we 595 * can potentially merge with, because on each 596 * side, there is either nothing there or what is 597 * there is still allocated. In that case, we don't 598 * want to remove r from the list; we simply want to 599 * change it to an unallocated region and return 600 * without freeing anything. 601 */ 602 r->r_flags &= ~RF_ALLOCATED; 603 return 0; 604 } 605 606 out: 607 kfree(r, M_RMAN); 608 return 0; 609 } 610 611 int 612 rman_release_resource(struct resource *r) 613 { 614 struct rman *rm = r->r_rm; 615 lwkt_tokref ilock; 616 int rv; 617 618 lwkt_gettoken(&ilock, rm->rm_slock); 619 rv = int_rman_release_resource(rm, r); 620 lwkt_reltoken(&ilock); 621 return (rv); 622 } 623 624 uint32_t 625 rman_make_alignment_flags(uint32_t size) 626 { 627 int i; 628 629 /* 630 * Find the hightest bit set, and add one if more than one bit 631 * set. We're effectively computing the ceil(log2(size)) here. 632 */ 633 for (i = 32; i > 0; i--) 634 if ((1 << i) & size) 635 break; 636 if (~(1 << i) & size) 637 i++; 638 639 return(RF_ALIGNMENT_LOG2(i)); 640 } 641