subr_kmem.c revision 1.55
1 /* $NetBSD: subr_kmem.c,v 1.55 2014/06/25 16:05:22 maxv Exp $ */ 2 3 /*- 4 * Copyright (c) 2009 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Andrew Doran. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /*- 33 * Copyright (c)2006 YAMAMOTO Takashi, 34 * All rights reserved. 35 * 36 * Redistribution and use in source and binary forms, with or without 37 * modification, are permitted provided that the following conditions 38 * are met: 39 * 1. Redistributions of source code must retain the above copyright 40 * notice, this list of conditions and the following disclaimer. 41 * 2. Redistributions in binary form must reproduce the above copyright 42 * notice, this list of conditions and the following disclaimer in the 43 * documentation and/or other materials provided with the distribution. 44 * 45 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 46 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 47 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 48 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 49 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 50 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 51 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 52 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 53 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 54 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 55 * SUCH DAMAGE. 56 */ 57 58 /* 59 * Allocator of kernel wired memory. This allocator has some debug features 60 * enabled with "option DIAGNOSTIC" and "option DEBUG". 61 */ 62 63 /* 64 * KMEM_SIZE: detect alloc/free size mismatch bugs. 65 * Prefix each allocations with a fixed-sized header and record the exact 66 * user-requested allocation size in it. When freeing, compare it with 67 * kmem_free's "size" argument. 68 */ 69 70 /* 71 * KMEM_REDZONE: detect overrun bugs. 72 * Add a 2-byte pattern (allocate some more bytes if needed) at the end 73 * of each allocated buffer. Check this pattern on kmem_free. 74 * 75 * KMEM_POISON: detect modify-after-free bugs. 76 * Fill freed (in the sense of kmem_free) memory with a garbage pattern. 77 * Check the pattern on allocation. 78 * 79 * KMEM_GUARD 80 * A kernel with "option DEBUG" has "kmguard" debugging feature compiled 81 * in. See the comment in uvm/uvm_kmguard.c for what kind of bugs it tries 82 * to detect. Even if compiled in, it's disabled by default because it's 83 * very expensive. You can enable it on boot by: 84 * boot -d 85 * db> w kmem_guard_depth 0t30000 86 * db> c 87 * 88 * The default value of kmem_guard_depth is 0, which means disabled. 89 * It can be changed by KMEM_GUARD_DEPTH kernel config option. 90 */ 91 92 #include <sys/cdefs.h> 93 __KERNEL_RCSID(0, "$NetBSD: subr_kmem.c,v 1.55 2014/06/25 16:05:22 maxv Exp $"); 94 95 #include <sys/param.h> 96 #include <sys/callback.h> 97 #include <sys/kmem.h> 98 #include <sys/pool.h> 99 #include <sys/debug.h> 100 #include <sys/lockdebug.h> 101 #include <sys/cpu.h> 102 103 #include <uvm/uvm_extern.h> 104 #include <uvm/uvm_map.h> 105 #include <uvm/uvm_kmguard.h> 106 107 #include <lib/libkern/libkern.h> 108 109 struct kmem_cache_info { 110 size_t kc_size; 111 const char * kc_name; 112 }; 113 114 static const struct kmem_cache_info kmem_cache_sizes[] = { 115 { 8, "kmem-8" }, 116 { 16, "kmem-16" }, 117 { 24, "kmem-24" }, 118 { 32, "kmem-32" }, 119 { 40, "kmem-40" }, 120 { 48, "kmem-48" }, 121 { 56, "kmem-56" }, 122 { 64, "kmem-64" }, 123 { 80, "kmem-80" }, 124 { 96, "kmem-96" }, 125 { 112, "kmem-112" }, 126 { 128, "kmem-128" }, 127 { 160, "kmem-160" }, 128 { 192, "kmem-192" }, 129 { 224, "kmem-224" }, 130 { 256, "kmem-256" }, 131 { 320, "kmem-320" }, 132 { 384, "kmem-384" }, 133 { 448, "kmem-448" }, 134 { 512, "kmem-512" }, 135 { 768, "kmem-768" }, 136 { 1024, "kmem-1024" }, 137 { 0, NULL } 138 }; 139 140 static const struct kmem_cache_info kmem_cache_big_sizes[] = { 141 { 2048, "kmem-2048" }, 142 { 4096, "kmem-4096" }, 143 { 8192, "kmem-8192" }, 144 { 16384, "kmem-16384" }, 145 { 0, NULL } 146 }; 147 148 /* 149 * KMEM_ALIGN is the smallest guaranteed alignment and also the 150 * smallest allocateable quantum. 151 * Every cache size >= CACHE_LINE_SIZE gets CACHE_LINE_SIZE alignment. 152 */ 153 #define KMEM_ALIGN 8 154 #define KMEM_SHIFT 3 155 #define KMEM_MAXSIZE 1024 156 #define KMEM_CACHE_COUNT (KMEM_MAXSIZE >> KMEM_SHIFT) 157 158 static pool_cache_t kmem_cache[KMEM_CACHE_COUNT] __cacheline_aligned; 159 static size_t kmem_cache_maxidx __read_mostly; 160 161 #define KMEM_BIG_ALIGN 2048 162 #define KMEM_BIG_SHIFT 11 163 #define KMEM_BIG_MAXSIZE 16384 164 #define KMEM_CACHE_BIG_COUNT (KMEM_BIG_MAXSIZE >> KMEM_BIG_SHIFT) 165 166 static pool_cache_t kmem_cache_big[KMEM_CACHE_BIG_COUNT] __cacheline_aligned; 167 static size_t kmem_cache_big_maxidx __read_mostly; 168 169 #if defined(DIAGNOSTIC) && defined(_HARDKERNEL) 170 #define KMEM_SIZE 171 #endif /* defined(DIAGNOSTIC) */ 172 173 #if defined(DEBUG) && defined(_HARDKERNEL) 174 #define KMEM_POISON 175 #define KMEM_REDZONE 176 #define KMEM_GUARD 177 #endif /* defined(DEBUG) */ 178 179 #if defined(KMEM_POISON) 180 static int kmem_poison_ctor(void *, void *, int); 181 static void kmem_poison_fill(void *, size_t); 182 static void kmem_poison_check(void *, size_t); 183 #else /* defined(KMEM_POISON) */ 184 #define kmem_poison_fill(p, sz) /* nothing */ 185 #define kmem_poison_check(p, sz) /* nothing */ 186 #endif /* defined(KMEM_POISON) */ 187 188 #if defined(KMEM_REDZONE) 189 #define REDZONE_SIZE 2 190 static void kmem_redzone_fill(void *p, size_t sz); 191 static void kmem_redzone_check(void *p, size_t sz); 192 #else /* defined(KMEM_REDZONE) */ 193 #define REDZONE_SIZE 0 194 #define kmem_redzone_fill(p, sz) /* nothing */ 195 #define kmem_redzone_check(p, sz) /* nothing */ 196 #endif /* defined(KMEM_REDZONE) */ 197 198 #if defined(KMEM_SIZE) 199 #define SIZE_SIZE (MAX(KMEM_ALIGN, sizeof(size_t))) 200 static void kmem_size_set(void *, size_t); 201 static void kmem_size_check(void *, size_t); 202 #else 203 #define SIZE_SIZE 0 204 #define kmem_size_set(p, sz) /* nothing */ 205 #define kmem_size_check(p, sz) /* nothing */ 206 #endif 207 208 #if defined(KMEM_GUARD) 209 #ifndef KMEM_GUARD_DEPTH 210 #define KMEM_GUARD_DEPTH 0 211 #endif 212 int kmem_guard_depth = KMEM_GUARD_DEPTH; 213 size_t kmem_guard_size; 214 static struct uvm_kmguard kmem_guard; 215 static void *kmem_freecheck; 216 #endif /* defined(KMEM_GUARD) */ 217 218 CTASSERT(KM_SLEEP == PR_WAITOK); 219 CTASSERT(KM_NOSLEEP == PR_NOWAIT); 220 221 /* 222 * kmem_intr_alloc: allocate wired memory. 223 */ 224 225 void * 226 kmem_intr_alloc(size_t requested_size, km_flag_t kmflags) 227 { 228 size_t allocsz, index; 229 size_t size; 230 pool_cache_t pc; 231 uint8_t *p; 232 233 KASSERT(requested_size > 0); 234 235 #ifdef KMEM_GUARD 236 if (requested_size <= kmem_guard_size) { 237 return uvm_kmguard_alloc(&kmem_guard, requested_size, 238 (kmflags & KM_SLEEP) != 0); 239 } 240 #endif 241 size = kmem_roundup_size(requested_size); 242 allocsz = size + SIZE_SIZE; 243 244 #ifdef KMEM_REDZONE 245 if (size - requested_size < REDZONE_SIZE) { 246 /* If there isn't enough space in the page padding, 247 * allocate two more bytes for the red zone. */ 248 allocsz += REDZONE_SIZE; 249 } 250 #endif 251 252 if ((index = ((allocsz -1) >> KMEM_SHIFT)) 253 < kmem_cache_maxidx) { 254 pc = kmem_cache[index]; 255 } else if ((index = ((allocsz - 1) >> KMEM_BIG_SHIFT)) 256 < kmem_cache_big_maxidx) { 257 pc = kmem_cache_big[index]; 258 } else { 259 int ret = uvm_km_kmem_alloc(kmem_va_arena, 260 (vsize_t)round_page(size), 261 ((kmflags & KM_SLEEP) ? VM_SLEEP : VM_NOSLEEP) 262 | VM_INSTANTFIT, (vmem_addr_t *)&p); 263 if (ret) { 264 return NULL; 265 } 266 FREECHECK_OUT(&kmem_freecheck, p); 267 return p; 268 } 269 270 p = pool_cache_get(pc, kmflags); 271 272 if (__predict_true(p != NULL)) { 273 kmem_poison_check(p, size); 274 FREECHECK_OUT(&kmem_freecheck, p); 275 kmem_size_set(p, requested_size); 276 kmem_redzone_fill(p, requested_size + SIZE_SIZE); 277 278 return p + SIZE_SIZE; 279 } 280 return p; 281 } 282 283 /* 284 * kmem_intr_zalloc: allocate zeroed wired memory. 285 */ 286 287 void * 288 kmem_intr_zalloc(size_t size, km_flag_t kmflags) 289 { 290 void *p; 291 292 p = kmem_intr_alloc(size, kmflags); 293 if (p != NULL) { 294 memset(p, 0, size); 295 } 296 return p; 297 } 298 299 /* 300 * kmem_intr_free: free wired memory allocated by kmem_alloc. 301 */ 302 303 void 304 kmem_intr_free(void *p, size_t requested_size) 305 { 306 size_t allocsz, index; 307 size_t size; 308 pool_cache_t pc; 309 310 KASSERT(p != NULL); 311 KASSERT(requested_size > 0); 312 313 #ifdef KMEM_GUARD 314 if (requested_size <= kmem_guard_size) { 315 uvm_kmguard_free(&kmem_guard, requested_size, p); 316 return; 317 } 318 #endif 319 320 size = kmem_roundup_size(requested_size); 321 allocsz = size + SIZE_SIZE; 322 323 #ifdef KMEM_REDZONE 324 if (size - requested_size < REDZONE_SIZE) { 325 allocsz += REDZONE_SIZE; 326 } 327 #endif 328 329 if ((index = ((allocsz -1) >> KMEM_SHIFT)) 330 < kmem_cache_maxidx) { 331 pc = kmem_cache[index]; 332 } else if ((index = ((allocsz - 1) >> KMEM_BIG_SHIFT)) 333 < kmem_cache_big_maxidx) { 334 pc = kmem_cache_big[index]; 335 } else { 336 FREECHECK_IN(&kmem_freecheck, p); 337 uvm_km_kmem_free(kmem_va_arena, (vaddr_t)p, 338 round_page(size)); 339 return; 340 } 341 342 p = (uint8_t *)p - SIZE_SIZE; 343 kmem_size_check(p, requested_size); 344 kmem_redzone_check(p, requested_size + SIZE_SIZE); 345 FREECHECK_IN(&kmem_freecheck, p); 346 LOCKDEBUG_MEM_CHECK(p, size); 347 kmem_poison_fill(p, allocsz); 348 349 pool_cache_put(pc, p); 350 } 351 352 /* ---- kmem API */ 353 354 /* 355 * kmem_alloc: allocate wired memory. 356 * => must not be called from interrupt context. 357 */ 358 359 void * 360 kmem_alloc(size_t size, km_flag_t kmflags) 361 { 362 363 KASSERTMSG((!cpu_intr_p() && !cpu_softintr_p()), 364 "kmem(9) should not be used from the interrupt context"); 365 return kmem_intr_alloc(size, kmflags); 366 } 367 368 /* 369 * kmem_zalloc: allocate zeroed wired memory. 370 * => must not be called from interrupt context. 371 */ 372 373 void * 374 kmem_zalloc(size_t size, km_flag_t kmflags) 375 { 376 377 KASSERTMSG((!cpu_intr_p() && !cpu_softintr_p()), 378 "kmem(9) should not be used from the interrupt context"); 379 return kmem_intr_zalloc(size, kmflags); 380 } 381 382 /* 383 * kmem_free: free wired memory allocated by kmem_alloc. 384 * => must not be called from interrupt context. 385 */ 386 387 void 388 kmem_free(void *p, size_t size) 389 { 390 391 KASSERT(!cpu_intr_p()); 392 KASSERT(!cpu_softintr_p()); 393 kmem_intr_free(p, size); 394 } 395 396 static size_t 397 kmem_create_caches(const struct kmem_cache_info *array, 398 pool_cache_t alloc_table[], size_t maxsize, int shift, int ipl) 399 { 400 size_t maxidx = 0; 401 size_t table_unit = (1 << shift); 402 size_t size = table_unit; 403 int i; 404 405 for (i = 0; array[i].kc_size != 0 ; i++) { 406 const char *name = array[i].kc_name; 407 size_t cache_size = array[i].kc_size; 408 struct pool_allocator *pa; 409 int flags = PR_NOALIGN; 410 pool_cache_t pc; 411 size_t align; 412 413 if ((cache_size & (CACHE_LINE_SIZE - 1)) == 0) 414 align = CACHE_LINE_SIZE; 415 else if ((cache_size & (PAGE_SIZE - 1)) == 0) 416 align = PAGE_SIZE; 417 else 418 align = KMEM_ALIGN; 419 420 if (cache_size < CACHE_LINE_SIZE) 421 flags |= PR_NOTOUCH; 422 423 /* check if we reached the requested size */ 424 if (cache_size > maxsize || cache_size > PAGE_SIZE) { 425 break; 426 } 427 if ((cache_size >> shift) > maxidx) { 428 maxidx = cache_size >> shift; 429 } 430 431 if ((cache_size >> shift) > maxidx) { 432 maxidx = cache_size >> shift; 433 } 434 435 pa = &pool_allocator_kmem; 436 #if defined(KMEM_POISON) 437 pc = pool_cache_init(cache_size, align, 0, flags, 438 name, pa, ipl, kmem_poison_ctor, 439 NULL, (void *)cache_size); 440 #else /* defined(KMEM_POISON) */ 441 pc = pool_cache_init(cache_size, align, 0, flags, 442 name, pa, ipl, NULL, NULL, NULL); 443 #endif /* defined(KMEM_POISON) */ 444 445 while (size <= cache_size) { 446 alloc_table[(size - 1) >> shift] = pc; 447 size += table_unit; 448 } 449 } 450 return maxidx; 451 } 452 453 void 454 kmem_init(void) 455 { 456 457 #ifdef KMEM_GUARD 458 uvm_kmguard_init(&kmem_guard, &kmem_guard_depth, &kmem_guard_size, 459 kmem_va_arena); 460 #endif 461 kmem_cache_maxidx = kmem_create_caches(kmem_cache_sizes, 462 kmem_cache, KMEM_MAXSIZE, KMEM_SHIFT, IPL_VM); 463 kmem_cache_big_maxidx = kmem_create_caches(kmem_cache_big_sizes, 464 kmem_cache_big, PAGE_SIZE, KMEM_BIG_SHIFT, IPL_VM); 465 } 466 467 size_t 468 kmem_roundup_size(size_t size) 469 { 470 471 return (size + (KMEM_ALIGN - 1)) & ~(KMEM_ALIGN - 1); 472 } 473 474 /* ------------------ DEBUG / DIAGNOSTIC ------------------ */ 475 476 #if defined(KMEM_POISON) || defined(KMEM_REDZONE) 477 #if defined(_LP64) 478 #define PRIME 0x9e37fffffffc0000UL 479 #else /* defined(_LP64) */ 480 #define PRIME 0x9e3779b1 481 #endif /* defined(_LP64) */ 482 #endif /* defined(KMEM_POISON) || defined(KMEM_REDZONE) */ 483 484 #if defined(KMEM_POISON) 485 static inline uint8_t 486 kmem_poison_pattern(const void *p) 487 { 488 return (uint8_t)(((uintptr_t)p) * PRIME 489 >> ((sizeof(uintptr_t) - sizeof(uint8_t))) * CHAR_BIT); 490 } 491 492 static int 493 kmem_poison_ctor(void *arg, void *obj, int flag) 494 { 495 size_t sz = (size_t)arg; 496 497 kmem_poison_fill(obj, sz); 498 499 return 0; 500 } 501 502 static void 503 kmem_poison_fill(void *p, size_t sz) 504 { 505 uint8_t *cp; 506 const uint8_t *ep; 507 508 cp = p; 509 ep = cp + sz; 510 while (cp < ep) { 511 *cp = kmem_poison_pattern(cp); 512 cp++; 513 } 514 } 515 516 static void 517 kmem_poison_check(void *p, size_t sz) 518 { 519 uint8_t *cp; 520 const uint8_t *ep; 521 522 cp = p; 523 ep = cp + sz; 524 while (cp < ep) { 525 const uint8_t expected = kmem_poison_pattern(cp); 526 527 if (*cp != expected) { 528 panic("%s: %p: 0x%02x != 0x%02x\n", 529 __func__, cp, *cp, expected); 530 } 531 cp++; 532 } 533 } 534 #endif /* defined(KMEM_POISON) */ 535 536 #if defined(KMEM_SIZE) 537 static void 538 kmem_size_set(void *p, size_t sz) 539 { 540 memcpy(p, &sz, sizeof(sz)); 541 } 542 543 static void 544 kmem_size_check(void *p, size_t sz) 545 { 546 size_t psz; 547 548 memcpy(&psz, p, sizeof(psz)); 549 if (psz != sz) { 550 panic("kmem_free(%p, %zu) != allocated size %zu", 551 (const uint8_t *)p + SIZE_SIZE, sz, psz); 552 } 553 } 554 #endif /* defined(KMEM_SIZE) */ 555 556 #if defined(KMEM_REDZONE) 557 static inline uint8_t 558 kmem_redzone_pattern(const void *p) 559 { 560 return (uint8_t)(((uintptr_t)p) * PRIME 561 >> ((sizeof(uintptr_t) - sizeof(uint8_t))) * CHAR_BIT); 562 } 563 564 static void 565 kmem_redzone_fill(void *p, size_t sz) 566 { 567 uint8_t *cp; 568 const uint8_t *ep; 569 570 cp = (uint8_t *)p + sz; 571 ep = cp + REDZONE_SIZE; 572 while (cp < ep) { 573 *cp = kmem_redzone_pattern(cp); 574 cp++; 575 } 576 } 577 578 static void 579 kmem_redzone_check(void *p, size_t sz) 580 { 581 uint8_t *cp; 582 const uint8_t *ep; 583 584 cp = (uint8_t *)p + sz; 585 ep = (uint8_t *)p + sz + REDZONE_SIZE; 586 while (cp < ep) { 587 const uint8_t expected = kmem_redzone_pattern(cp); 588 589 if (*cp != expected) { 590 panic("%s: %p: 0x%02x != 0x%02x\n", 591 __func__, cp, *cp, expected); 592 } 593 cp++; 594 } 595 } 596 #endif /* defined(KMEM_REDZONE) */ 597 598 599 /* 600 * Used to dynamically allocate string with kmem accordingly to format. 601 */ 602 char * 603 kmem_asprintf(const char *fmt, ...) 604 { 605 int size __diagused, len; 606 va_list va; 607 char *str; 608 609 va_start(va, fmt); 610 len = vsnprintf(NULL, 0, fmt, va); 611 va_end(va); 612 613 str = kmem_alloc(len + 1, KM_SLEEP); 614 615 va_start(va, fmt); 616 size = vsnprintf(str, len + 1, fmt, va); 617 va_end(va); 618 619 KASSERT(size == len); 620 621 return str; 622 } 623
Indexes created Mon Sep 22 13:09:51 GMT 2025