subr_kmem.c revision 1.86
1 /* $NetBSD: subr_kmem.c,v 1.86 2022/05/30 21:42:02 mrg Exp $ */ 2 3 /* 4 * Copyright (c) 2009-2020 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 and Maxime Villard. 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 * Append to each allocation a fixed-sized footer and record the exact 66 * user-requested allocation size in it. When freeing, compare it with 67 * kmem_free's "size" argument. 68 * 69 * This option is enabled on DIAGNOSTIC. 70 * 71 * |CHUNK|CHUNK|CHUNK|CHUNK|CHUNK|CHUNK|CHUNK|CHUNK|CHUNK| | 72 * +-----+-----+-----+-----+-----+-----+-----+-----+-----+-+ 73 * | | | | | | | | |/////|U| 74 * | | | | | | | | |/HSZ/|U| 75 * | | | | | | | | |/////|U| 76 * +-----+-----+-----+-----+-----+-----+-----+-----+-----+-+ 77 * | Buffer usable by the caller (requested size) |Size |Unused 78 */ 79 80 #include <sys/cdefs.h> 81 __KERNEL_RCSID(0, "$NetBSD: subr_kmem.c,v 1.86 2022/05/30 21:42:02 mrg Exp $"); 82 83 #ifdef _KERNEL_OPT 84 #include "opt_kmem.h" 85 #endif 86 87 #include <sys/param.h> 88 #include <sys/callback.h> 89 #include <sys/kmem.h> 90 #include <sys/pool.h> 91 #include <sys/debug.h> 92 #include <sys/lockdebug.h> 93 #include <sys/cpu.h> 94 #include <sys/asan.h> 95 #include <sys/msan.h> 96 #include <sys/sdt.h> 97 98 #include <uvm/uvm_extern.h> 99 #include <uvm/uvm_map.h> 100 101 #include <lib/libkern/libkern.h> 102 103 struct kmem_cache_info { 104 size_t kc_size; 105 const char * kc_name; 106 #ifdef KDTRACE_HOOKS 107 const id_t *kc_alloc_probe_id; 108 const id_t *kc_free_probe_id; 109 #endif 110 }; 111 112 #define KMEM_CACHE_SIZES(F) \ 113 F(8, kmem-00008, kmem__00008) \ 114 F(16, kmem-00016, kmem__00016) \ 115 F(24, kmem-00024, kmem__00024) \ 116 F(32, kmem-00032, kmem__00032) \ 117 F(40, kmem-00040, kmem__00040) \ 118 F(48, kmem-00048, kmem__00048) \ 119 F(56, kmem-00056, kmem__00056) \ 120 F(64, kmem-00064, kmem__00064) \ 121 F(80, kmem-00080, kmem__00080) \ 122 F(96, kmem-00096, kmem__00096) \ 123 F(112, kmem-00112, kmem__00112) \ 124 F(128, kmem-00128, kmem__00128) \ 125 F(160, kmem-00160, kmem__00160) \ 126 F(192, kmem-00192, kmem__00192) \ 127 F(224, kmem-00224, kmem__00224) \ 128 F(256, kmem-00256, kmem__00256) \ 129 F(320, kmem-00320, kmem__00320) \ 130 F(384, kmem-00384, kmem__00384) \ 131 F(448, kmem-00448, kmem__00448) \ 132 F(512, kmem-00512, kmem__00512) \ 133 F(768, kmem-00768, kmem__00768) \ 134 F(1024, kmem-01024, kmem__01024) \ 135 /* end of KMEM_CACHE_SIZES */ 136 137 #define KMEM_CACHE_BIG_SIZES(F) \ 138 F(2048, kmem-02048, kmem__02048) \ 139 F(4096, kmem-04096, kmem__04096) \ 140 F(8192, kmem-08192, kmem__08192) \ 141 F(16384, kmem-16384, kmem__16384) \ 142 /* end of KMEM_CACHE_BIG_SIZES */ 143 144 /* sdt:kmem:alloc:kmem-* probes */ 145 #define F(SZ, NAME, PROBENAME) \ 146 SDT_PROBE_DEFINE4(sdt, kmem, alloc, PROBENAME, \ 147 "void *"/*ptr*/, \ 148 "size_t"/*requested_size*/, \ 149 "size_t"/*allocated_size*/, \ 150 "km_flag_t"/*kmflags*/); 151 KMEM_CACHE_SIZES(F); 152 KMEM_CACHE_BIG_SIZES(F); 153 #undef F 154 155 /* sdt:kmem:free:kmem-* probes */ 156 #define F(SZ, NAME, PROBENAME) \ 157 SDT_PROBE_DEFINE3(sdt, kmem, free, PROBENAME, \ 158 "void *"/*ptr*/, \ 159 "size_t"/*requested_size*/, \ 160 "size_t"/*allocated_size*/); 161 KMEM_CACHE_SIZES(F); 162 KMEM_CACHE_BIG_SIZES(F); 163 #undef F 164 165 /* sdt:kmem:alloc:large, sdt:kmem:free:large probes */ 166 SDT_PROBE_DEFINE4(sdt, kmem, alloc, large, 167 "void *"/*ptr*/, 168 "size_t"/*requested_size*/, 169 "size_t"/*allocated_size*/, 170 "km_flag_t"/*kmflags*/); 171 SDT_PROBE_DEFINE3(sdt, kmem, free, large, 172 "void *"/*ptr*/, 173 "size_t"/*requested_size*/, 174 "size_t"/*allocated_size*/); 175 176 #ifdef KDTRACE_HOOKS 177 #define F(SZ, NAME, PROBENAME) \ 178 { SZ, #NAME, \ 179 &sdt_sdt_kmem_alloc_##PROBENAME->id, \ 180 &sdt_sdt_kmem_free_##PROBENAME->id }, 181 #else 182 #define F(SZ, NAME, PROBENAME) { SZ, #NAME }, 183 #endif 184 185 static const struct kmem_cache_info kmem_cache_sizes[] = { 186 KMEM_CACHE_SIZES(F) 187 #ifndef KDTRACE_HOOKS 188 { 0, NULL } 189 #endif 190 }; 191 192 static const struct kmem_cache_info kmem_cache_big_sizes[] = { 193 KMEM_CACHE_BIG_SIZES(F) 194 #ifndef KDTRACE_HOOKS 195 { 0, NULL } 196 #endif 197 }; 198 199 #undef F 200 201 /* 202 * KMEM_ALIGN is the smallest guaranteed alignment and also the 203 * smallest allocateable quantum. 204 * Every cache size >= CACHE_LINE_SIZE gets CACHE_LINE_SIZE alignment. 205 */ 206 #define KMEM_ALIGN 8 207 #define KMEM_SHIFT 3 208 #define KMEM_MAXSIZE 1024 209 #define KMEM_CACHE_COUNT (KMEM_MAXSIZE >> KMEM_SHIFT) 210 211 static pool_cache_t kmem_cache[KMEM_CACHE_COUNT] __cacheline_aligned; 212 static size_t kmem_cache_maxidx __read_mostly; 213 214 #define KMEM_BIG_ALIGN 2048 215 #define KMEM_BIG_SHIFT 11 216 #define KMEM_BIG_MAXSIZE 16384 217 #define KMEM_CACHE_BIG_COUNT (KMEM_BIG_MAXSIZE >> KMEM_BIG_SHIFT) 218 219 static pool_cache_t kmem_cache_big[KMEM_CACHE_BIG_COUNT] __cacheline_aligned; 220 static size_t kmem_cache_big_maxidx __read_mostly; 221 222 #if defined(DIAGNOSTIC) && defined(_HARDKERNEL) 223 #define KMEM_SIZE 224 #endif 225 226 #if defined(DEBUG) && defined(_HARDKERNEL) 227 static void *kmem_freecheck; 228 #endif 229 230 #if defined(KMEM_SIZE) 231 #define SIZE_SIZE sizeof(size_t) 232 static void kmem_size_set(void *, size_t); 233 static void kmem_size_check(void *, size_t); 234 #else 235 #define SIZE_SIZE 0 236 #define kmem_size_set(p, sz) /* nothing */ 237 #define kmem_size_check(p, sz) /* nothing */ 238 #endif 239 240 #ifndef KDTRACE_HOOKS 241 242 static const id_t **const kmem_cache_alloc_probe_id = NULL; 243 static const id_t **const kmem_cache_big_alloc_probe_id = NULL; 244 static const id_t **const kmem_cache_free_probe_id = NULL; 245 static const id_t **const kmem_cache_big_free_probe_id = NULL; 246 247 #define KMEM_CACHE_PROBE(ARRAY, INDEX, PTR, REQSIZE, ALLOCSIZE, FLAGS) \ 248 __nothing 249 250 #else 251 252 static const id_t *kmem_cache_alloc_probe_id[KMEM_CACHE_COUNT]; 253 static const id_t *kmem_cache_big_alloc_probe_id[KMEM_CACHE_COUNT]; 254 static const id_t *kmem_cache_free_probe_id[KMEM_CACHE_COUNT]; 255 static const id_t *kmem_cache_big_free_probe_id[KMEM_CACHE_COUNT]; 256 257 #define KMEM_CACHE_PROBE(ARRAY, INDEX, PTR, REQSIZE, ALLOCSIZE, FLAGS) do \ 258 { \ 259 id_t id; \ 260 \ 261 KDASSERT((INDEX) < __arraycount(ARRAY)); \ 262 if (__predict_false((id = *(ARRAY)[INDEX]) != 0)) { \ 263 (*sdt_probe_func)(id, \ 264 (uintptr_t)(PTR), \ 265 (uintptr_t)(REQSIZE), \ 266 (uintptr_t)(ALLOCSIZE), \ 267 (uintptr_t)(FLAGS), \ 268 (uintptr_t)0); \ 269 } \ 270 } while (0) 271 272 #endif /* KDTRACE_HOOKS */ 273 274 #define KMEM_CACHE_ALLOC_PROBE(I, P, RS, AS, F) \ 275 KMEM_CACHE_PROBE(kmem_cache_alloc_probe_id, I, P, RS, AS, F) 276 #define KMEM_CACHE_BIG_ALLOC_PROBE(I, P, RS, AS, F) \ 277 KMEM_CACHE_PROBE(kmem_cache_big_alloc_probe_id, I, P, RS, AS, F) 278 #define KMEM_CACHE_FREE_PROBE(I, P, RS, AS) \ 279 KMEM_CACHE_PROBE(kmem_cache_free_probe_id, I, P, RS, AS, 0) 280 #define KMEM_CACHE_BIG_FREE_PROBE(I, P, RS, AS) \ 281 KMEM_CACHE_PROBE(kmem_cache_big_free_probe_id, I, P, RS, AS, 0) 282 283 CTASSERT(KM_SLEEP == PR_WAITOK); 284 CTASSERT(KM_NOSLEEP == PR_NOWAIT); 285 286 /* 287 * kmem_intr_alloc: allocate wired memory. 288 */ 289 void * 290 kmem_intr_alloc(size_t requested_size, km_flag_t kmflags) 291 { 292 #ifdef KASAN 293 const size_t origsize = requested_size; 294 #endif 295 size_t allocsz, index; 296 size_t size; 297 pool_cache_t pc; 298 uint8_t *p; 299 300 KASSERT(requested_size > 0); 301 302 KASSERT((kmflags & KM_SLEEP) || (kmflags & KM_NOSLEEP)); 303 KASSERT(!(kmflags & KM_SLEEP) || !(kmflags & KM_NOSLEEP)); 304 305 kasan_add_redzone(&requested_size); 306 size = kmem_roundup_size(requested_size); 307 allocsz = size + SIZE_SIZE; 308 309 if ((index = ((allocsz - 1) >> KMEM_SHIFT)) 310 < kmem_cache_maxidx) { 311 pc = kmem_cache[index]; 312 p = pool_cache_get(pc, kmflags); 313 KMEM_CACHE_ALLOC_PROBE(index, 314 p, requested_size, allocsz, kmflags); 315 } else if ((index = ((allocsz - 1) >> KMEM_BIG_SHIFT)) 316 < kmem_cache_big_maxidx) { 317 pc = kmem_cache_big[index]; 318 p = pool_cache_get(pc, kmflags); 319 KMEM_CACHE_BIG_ALLOC_PROBE(index, 320 p, requested_size, allocsz, kmflags); 321 } else { 322 int ret = uvm_km_kmem_alloc(kmem_va_arena, 323 (vsize_t)round_page(size), 324 ((kmflags & KM_SLEEP) ? VM_SLEEP : VM_NOSLEEP) 325 | VM_INSTANTFIT, (vmem_addr_t *)&p); 326 SDT_PROBE4(sdt, kmem, alloc, large, 327 ret ? NULL : p, requested_size, round_page(size), kmflags); 328 if (ret) { 329 return NULL; 330 } 331 FREECHECK_OUT(&kmem_freecheck, p); 332 return p; 333 } 334 335 if (__predict_true(p != NULL)) { 336 FREECHECK_OUT(&kmem_freecheck, p); 337 kmem_size_set(p, requested_size); 338 kasan_mark(p, origsize, size, KASAN_KMEM_REDZONE); 339 return p; 340 } 341 return p; 342 } 343 344 /* 345 * kmem_intr_zalloc: allocate zeroed wired memory. 346 */ 347 void * 348 kmem_intr_zalloc(size_t size, km_flag_t kmflags) 349 { 350 void *p; 351 352 p = kmem_intr_alloc(size, kmflags); 353 if (p != NULL) { 354 memset(p, 0, size); 355 } 356 return p; 357 } 358 359 /* 360 * kmem_intr_free: free wired memory allocated by kmem_alloc. 361 */ 362 void 363 kmem_intr_free(void *p, size_t requested_size) 364 { 365 size_t allocsz, index; 366 size_t size; 367 pool_cache_t pc; 368 369 KASSERT(p != NULL); 370 KASSERTMSG(requested_size > 0, "kmem_intr_free(%p, 0)", p); 371 372 kasan_add_redzone(&requested_size); 373 size = kmem_roundup_size(requested_size); 374 allocsz = size + SIZE_SIZE; 375 376 if ((index = ((allocsz - 1) >> KMEM_SHIFT)) 377 < kmem_cache_maxidx) { 378 KMEM_CACHE_FREE_PROBE(index, p, requested_size, allocsz); 379 pc = kmem_cache[index]; 380 } else if ((index = ((allocsz - 1) >> KMEM_BIG_SHIFT)) 381 < kmem_cache_big_maxidx) { 382 KMEM_CACHE_BIG_FREE_PROBE(index, p, requested_size, allocsz); 383 pc = kmem_cache_big[index]; 384 } else { 385 FREECHECK_IN(&kmem_freecheck, p); 386 SDT_PROBE3(sdt, kmem, free, large, 387 p, requested_size, round_page(size)); 388 uvm_km_kmem_free(kmem_va_arena, (vaddr_t)p, 389 round_page(size)); 390 return; 391 } 392 393 kasan_mark(p, size, size, 0); 394 395 kmem_size_check(p, requested_size); 396 FREECHECK_IN(&kmem_freecheck, p); 397 LOCKDEBUG_MEM_CHECK(p, size); 398 399 pool_cache_put(pc, p); 400 } 401 402 /* -------------------------------- Kmem API -------------------------------- */ 403 404 /* 405 * kmem_alloc: allocate wired memory. 406 * => must not be called from interrupt context. 407 */ 408 void * 409 kmem_alloc(size_t size, km_flag_t kmflags) 410 { 411 void *v; 412 413 KASSERTMSG((!cpu_intr_p() && !cpu_softintr_p()), 414 "kmem(9) should not be used from the interrupt context"); 415 v = kmem_intr_alloc(size, kmflags); 416 if (__predict_true(v != NULL)) { 417 kmsan_mark(v, size, KMSAN_STATE_UNINIT); 418 kmsan_orig(v, size, KMSAN_TYPE_KMEM, __RET_ADDR); 419 } 420 KASSERT(v || (kmflags & KM_NOSLEEP) != 0); 421 return v; 422 } 423 424 /* 425 * kmem_zalloc: allocate zeroed wired memory. 426 * => must not be called from interrupt context. 427 */ 428 void * 429 kmem_zalloc(size_t size, km_flag_t kmflags) 430 { 431 void *v; 432 433 KASSERTMSG((!cpu_intr_p() && !cpu_softintr_p()), 434 "kmem(9) should not be used from the interrupt context"); 435 v = kmem_intr_zalloc(size, kmflags); 436 KASSERT(v || (kmflags & KM_NOSLEEP) != 0); 437 return v; 438 } 439 440 /* 441 * kmem_free: free wired memory allocated by kmem_alloc. 442 * => must not be called from interrupt context. 443 */ 444 void 445 kmem_free(void *p, size_t size) 446 { 447 KASSERT(!cpu_intr_p()); 448 KASSERT(!cpu_softintr_p()); 449 kmem_intr_free(p, size); 450 kmsan_mark(p, size, KMSAN_STATE_INITED); 451 } 452 453 static size_t 454 kmem_create_caches(const struct kmem_cache_info *array, 455 const id_t *alloc_probe_table[], const id_t *free_probe_table[], 456 pool_cache_t alloc_table[], size_t maxsize, int shift, int ipl) 457 { 458 size_t maxidx = 0; 459 size_t table_unit = (1 << shift); 460 size_t size = table_unit; 461 int i; 462 463 for (i = 0; array[i].kc_size != 0 ; i++) { 464 const char *name = array[i].kc_name; 465 size_t cache_size = array[i].kc_size; 466 struct pool_allocator *pa; 467 int flags = 0; 468 pool_cache_t pc; 469 size_t align; 470 471 /* check if we reached the requested size */ 472 if (cache_size > maxsize || cache_size > PAGE_SIZE) { 473 break; 474 } 475 476 /* 477 * Exclude caches with size not a factor or multiple of the 478 * coherency unit. 479 */ 480 if (cache_size < COHERENCY_UNIT) { 481 if (COHERENCY_UNIT % cache_size > 0) { 482 continue; 483 } 484 flags |= PR_NOTOUCH; 485 align = KMEM_ALIGN; 486 } else if ((cache_size & (PAGE_SIZE - 1)) == 0) { 487 align = PAGE_SIZE; 488 } else { 489 if ((cache_size % COHERENCY_UNIT) > 0) { 490 continue; 491 } 492 align = COHERENCY_UNIT; 493 } 494 495 if ((cache_size >> shift) > maxidx) { 496 maxidx = cache_size >> shift; 497 } 498 499 pa = &pool_allocator_kmem; 500 pc = pool_cache_init(cache_size, align, 0, flags, 501 name, pa, ipl, NULL, NULL, NULL); 502 503 while (size <= cache_size) { 504 alloc_table[(size - 1) >> shift] = pc; 505 #ifdef KDTRACE_HOOKS 506 if (alloc_probe_table) { 507 alloc_probe_table[(size - 1) >> shift] = 508 array[i].kc_alloc_probe_id; 509 } 510 if (free_probe_table) { 511 free_probe_table[(size - 1) >> shift] = 512 array[i].kc_free_probe_id; 513 } 514 #endif 515 size += table_unit; 516 } 517 } 518 return maxidx; 519 } 520 521 void 522 kmem_init(void) 523 { 524 kmem_cache_maxidx = kmem_create_caches(kmem_cache_sizes, 525 kmem_cache_alloc_probe_id, kmem_cache_free_probe_id, 526 kmem_cache, KMEM_MAXSIZE, KMEM_SHIFT, IPL_VM); 527 kmem_cache_big_maxidx = kmem_create_caches(kmem_cache_big_sizes, 528 kmem_cache_big_alloc_probe_id, kmem_cache_big_free_probe_id, 529 kmem_cache_big, PAGE_SIZE, KMEM_BIG_SHIFT, IPL_VM); 530 } 531 532 size_t 533 kmem_roundup_size(size_t size) 534 { 535 return (size + (KMEM_ALIGN - 1)) & ~(KMEM_ALIGN - 1); 536 } 537 538 /* 539 * Used to dynamically allocate string with kmem accordingly to format. 540 */ 541 char * 542 kmem_asprintf(const char *fmt, ...) 543 { 544 int size __diagused, len; 545 va_list va; 546 char *str; 547 548 va_start(va, fmt); 549 len = vsnprintf(NULL, 0, fmt, va); 550 va_end(va); 551 552 str = kmem_alloc(len + 1, KM_SLEEP); 553 554 va_start(va, fmt); 555 size = vsnprintf(str, len + 1, fmt, va); 556 va_end(va); 557 558 KASSERT(size == len); 559 560 return str; 561 } 562 563 char * 564 kmem_strdupsize(const char *str, size_t *lenp, km_flag_t flags) 565 { 566 size_t len = strlen(str) + 1; 567 char *ptr = kmem_alloc(len, flags); 568 if (ptr == NULL) 569 return NULL; 570 571 if (lenp) 572 *lenp = len; 573 memcpy(ptr, str, len); 574 return ptr; 575 } 576 577 char * 578 kmem_strndup(const char *str, size_t maxlen, km_flag_t flags) 579 { 580 KASSERT(str != NULL); 581 KASSERT(maxlen != 0); 582 583 size_t len = strnlen(str, maxlen); 584 char *ptr = kmem_alloc(len + 1, flags); 585 if (ptr == NULL) 586 return NULL; 587 588 memcpy(ptr, str, len); 589 ptr[len] = '\0'; 590 591 return ptr; 592 } 593 594 void 595 kmem_strfree(char *str) 596 { 597 if (str == NULL) 598 return; 599 600 kmem_free(str, strlen(str) + 1); 601 } 602 603 /* 604 * Utility routine to maybe-allocate a temporary buffer if the size 605 * is larger than we're willing to put on the stack. 606 */ 607 void * 608 kmem_tmpbuf_alloc(size_t size, void *stackbuf, size_t stackbufsize, 609 km_flag_t flags) 610 { 611 if (size <= stackbufsize) { 612 return stackbuf; 613 } 614 615 return kmem_alloc(size, flags); 616 } 617 618 void 619 kmem_tmpbuf_free(void *buf, size_t size, void *stackbuf) 620 { 621 if (buf != stackbuf) { 622 kmem_free(buf, size); 623 } 624 } 625 626 /* --------------------------- DEBUG / DIAGNOSTIC --------------------------- */ 627 628 #if defined(KMEM_SIZE) 629 static void 630 kmem_size_set(void *p, size_t sz) 631 { 632 memcpy((char *)p + sz, &sz, sizeof(size_t)); 633 } 634 635 static void 636 kmem_size_check(void *p, size_t sz) 637 { 638 size_t hsz; 639 640 memcpy(&hsz, (char *)p + sz, sizeof(size_t)); 641 642 if (hsz != sz) { 643 panic("kmem_free(%p, %zu) != allocated size %zu; overwrote?", 644 p, sz, hsz); 645 } 646 647 memset((char *)p + sz, 0xff, sizeof(size_t)); 648 } 649 #endif /* defined(KMEM_SIZE) */ 650
Indexes created Mon Sep 22 10:09:38 GMT 2025