1 /* $NetBSD: subr_kmem.c,v 1.89 2023/09/10 14:29:13 ad Exp $ */ 2 3 /* 4 * Copyright (c) 2009-2023 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 1.89 2023/09/10 14:29:13 ad 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 { 0 } 188 }; 189 190 static const struct kmem_cache_info kmem_cache_big_sizes[] = { 191 KMEM_CACHE_BIG_SIZES(F) 192 { 0 } 193 }; 194 195 #undef F 196 197 /* 198 * KMEM_ALIGN is the smallest guaranteed alignment and also the 199 * smallest allocateable quantum. 200 * Every cache size >= CACHE_LINE_SIZE gets CACHE_LINE_SIZE alignment. 201 */ 202 #define KMEM_ALIGN 8 203 #define KMEM_SHIFT 3 204 #define KMEM_MAXSIZE 1024 205 #define KMEM_CACHE_COUNT (KMEM_MAXSIZE >> KMEM_SHIFT) 206 207 static pool_cache_t kmem_cache[KMEM_CACHE_COUNT] __cacheline_aligned; 208 static size_t kmem_cache_maxidx __read_mostly; 209 210 #define KMEM_BIG_ALIGN 2048 211 #define KMEM_BIG_SHIFT 11 212 #define KMEM_BIG_MAXSIZE 16384 213 #define KMEM_CACHE_BIG_COUNT (KMEM_BIG_MAXSIZE >> KMEM_BIG_SHIFT) 214 215 static pool_cache_t kmem_cache_big[KMEM_CACHE_BIG_COUNT] __cacheline_aligned; 216 static size_t kmem_cache_big_maxidx __read_mostly; 217 218 #if defined(DIAGNOSTIC) && defined(_HARDKERNEL) 219 #define KMEM_SIZE 220 #endif 221 222 #if defined(DEBUG) && defined(_HARDKERNEL) 223 static void *kmem_freecheck; 224 #endif 225 226 #if defined(KMEM_SIZE) 227 #define SIZE_SIZE sizeof(size_t) 228 static void kmem_size_set(void *, size_t); 229 static void kmem_size_check(void *, size_t); 230 #else 231 #define SIZE_SIZE 0 232 #define kmem_size_set(p, sz) /* nothing */ 233 #define kmem_size_check(p, sz) /* nothing */ 234 #endif 235 236 #ifndef KDTRACE_HOOKS 237 238 static const id_t **const kmem_cache_alloc_probe_id = NULL; 239 static const id_t **const kmem_cache_big_alloc_probe_id = NULL; 240 static const id_t **const kmem_cache_free_probe_id = NULL; 241 static const id_t **const kmem_cache_big_free_probe_id = NULL; 242 243 #define KMEM_CACHE_PROBE(ARRAY, INDEX, PTR, REQSIZE, ALLOCSIZE, FLAGS) \ 244 __nothing 245 246 #else 247 248 static const id_t *kmem_cache_alloc_probe_id[KMEM_CACHE_COUNT]; 249 static const id_t *kmem_cache_big_alloc_probe_id[KMEM_CACHE_COUNT]; 250 static const id_t *kmem_cache_free_probe_id[KMEM_CACHE_COUNT]; 251 static const id_t *kmem_cache_big_free_probe_id[KMEM_CACHE_COUNT]; 252 253 #define KMEM_CACHE_PROBE(ARRAY, INDEX, PTR, REQSIZE, ALLOCSIZE, FLAGS) do \ 254 { \ 255 id_t id; \ 256 \ 257 KDASSERT((INDEX) < __arraycount(ARRAY)); \ 258 if (__predict_false((id = *(ARRAY)[INDEX]) != 0)) { \ 259 (*sdt_probe_func)(id, \ 260 (uintptr_t)(PTR), \ 261 (uintptr_t)(REQSIZE), \ 262 (uintptr_t)(ALLOCSIZE), \ 263 (uintptr_t)(FLAGS), \ 264 (uintptr_t)0); \ 265 } \ 266 } while (0) 267 268 #endif /* KDTRACE_HOOKS */ 269 270 #define KMEM_CACHE_ALLOC_PROBE(I, P, RS, AS, F) \ 271 KMEM_CACHE_PROBE(kmem_cache_alloc_probe_id, I, P, RS, AS, F) 272 #define KMEM_CACHE_BIG_ALLOC_PROBE(I, P, RS, AS, F) \ 273 KMEM_CACHE_PROBE(kmem_cache_big_alloc_probe_id, I, P, RS, AS, F) 274 #define KMEM_CACHE_FREE_PROBE(I, P, RS, AS) \ 275 KMEM_CACHE_PROBE(kmem_cache_free_probe_id, I, P, RS, AS, 0) 276 #define KMEM_CACHE_BIG_FREE_PROBE(I, P, RS, AS) \ 277 KMEM_CACHE_PROBE(kmem_cache_big_free_probe_id, I, P, RS, AS, 0) 278 279 CTASSERT(KM_SLEEP == PR_WAITOK); 280 CTASSERT(KM_NOSLEEP == PR_NOWAIT); 281 282 /* 283 * kmem_intr_alloc: allocate wired memory. 284 */ 285 void * 286 kmem_intr_alloc(size_t requested_size, km_flag_t kmflags) 287 { 288 #ifdef KASAN 289 const size_t origsize = requested_size; 290 #endif 291 size_t allocsz, index; 292 size_t size; 293 pool_cache_t pc; 294 uint8_t *p; 295 296 KASSERT(requested_size > 0); 297 298 KASSERT((kmflags & KM_SLEEP) || (kmflags & KM_NOSLEEP)); 299 KASSERT(!(kmflags & KM_SLEEP) || !(kmflags & KM_NOSLEEP)); 300 301 kasan_add_redzone(&requested_size); 302 size = kmem_roundup_size(requested_size); 303 allocsz = size + SIZE_SIZE; 304 305 if ((index = ((allocsz - 1) >> KMEM_SHIFT)) 306 < kmem_cache_maxidx) { 307 pc = kmem_cache[index]; 308 p = pool_cache_get(pc, kmflags); 309 KMEM_CACHE_ALLOC_PROBE(index, 310 p, requested_size, allocsz, kmflags); 311 } else if ((index = ((allocsz - 1) >> KMEM_BIG_SHIFT)) 312 < kmem_cache_big_maxidx) { 313 pc = kmem_cache_big[index]; 314 p = pool_cache_get(pc, kmflags); 315 KMEM_CACHE_BIG_ALLOC_PROBE(index, 316 p, requested_size, allocsz, kmflags); 317 } else { 318 int ret = uvm_km_kmem_alloc(kmem_va_arena, 319 (vsize_t)round_page(size), 320 ((kmflags & KM_SLEEP) ? VM_SLEEP : VM_NOSLEEP) 321 | VM_INSTANTFIT, (vmem_addr_t *)&p); 322 SDT_PROBE4(sdt, kmem, alloc, large, 323 ret ? NULL : p, requested_size, round_page(size), kmflags); 324 if (ret) { 325 return NULL; 326 } 327 FREECHECK_OUT(&kmem_freecheck, p); 328 KASSERT(size < coherency_unit || 329 ALIGNED_POINTER(p, coherency_unit)); 330 return p; 331 } 332 333 if (__predict_true(p != NULL)) { 334 FREECHECK_OUT(&kmem_freecheck, p); 335 kmem_size_set(p, requested_size); 336 kasan_mark(p, origsize, size, KASAN_KMEM_REDZONE); 337 return p; 338 } 339 340 KASSERT(size < coherency_unit || ALIGNED_POINTER(p, coherency_unit)); 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 (__predict_true(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 KASSERT(!cpu_intr_p()); 414 KASSERT(!cpu_softintr_p()); 415 416 v = kmem_intr_alloc(size, kmflags); 417 if (__predict_true(v != NULL)) { 418 kmsan_mark(v, size, KMSAN_STATE_UNINIT); 419 kmsan_orig(v, size, KMSAN_TYPE_KMEM, __RET_ADDR); 420 } 421 KASSERT(v || (kmflags & KM_NOSLEEP) != 0); 422 return v; 423 } 424 425 /* 426 * kmem_zalloc: allocate zeroed wired memory. 427 * => must not be called from interrupt context. 428 */ 429 void * 430 kmem_zalloc(size_t size, km_flag_t kmflags) 431 { 432 void *v; 433 434 KASSERT(!cpu_intr_p()); 435 KASSERT(!cpu_softintr_p()); 436 437 v = kmem_intr_zalloc(size, kmflags); 438 KASSERT(v || (kmflags & KM_NOSLEEP) != 0); 439 return v; 440 } 441 442 /* 443 * kmem_free: free wired memory allocated by kmem_alloc. 444 * => must not be called from interrupt context. 445 */ 446 void 447 kmem_free(void *p, size_t size) 448 { 449 450 KASSERT(!cpu_intr_p()); 451 KASSERT(!cpu_softintr_p()); 452 453 kmem_intr_free(p, size); 454 kmsan_mark(p, size, KMSAN_STATE_INITED); 455 } 456 457 static size_t 458 kmem_create_caches(const struct kmem_cache_info *array, 459 const id_t *alloc_probe_table[], const id_t *free_probe_table[], 460 pool_cache_t alloc_table[], size_t maxsize, int shift, int ipl) 461 { 462 size_t maxidx = 0; 463 size_t table_unit = (1 << shift); 464 size_t size = table_unit; 465 int i; 466 467 for (i = 0; array[i].kc_size != 0 ; i++) { 468 const char *name = array[i].kc_name; 469 size_t cache_size = array[i].kc_size; 470 struct pool_allocator *pa; 471 int flags = 0; 472 pool_cache_t pc; 473 size_t align; 474 475 /* check if we reached the requested size */ 476 if (cache_size > maxsize || cache_size > PAGE_SIZE) { 477 break; 478 } 479 480 /* 481 * Exclude caches with size not a factor or multiple of the 482 * coherency unit. 483 */ 484 if (cache_size < COHERENCY_UNIT) { 485 if (COHERENCY_UNIT % cache_size > 0) { 486 continue; 487 } 488 flags |= PR_NOTOUCH; 489 align = KMEM_ALIGN; 490 } else if ((cache_size & (PAGE_SIZE - 1)) == 0) { 491 align = PAGE_SIZE; 492 } else { 493 if ((cache_size % COHERENCY_UNIT) > 0) { 494 continue; 495 } 496 align = COHERENCY_UNIT; 497 } 498 499 if ((cache_size >> shift) > maxidx) { 500 maxidx = cache_size >> shift; 501 } 502 503 pa = &pool_allocator_kmem; 504 pc = pool_cache_init(cache_size, align, 0, flags, 505 name, pa, ipl, NULL, NULL, NULL); 506 507 while (size <= cache_size) { 508 alloc_table[(size - 1) >> shift] = pc; 509 #ifdef KDTRACE_HOOKS 510 if (alloc_probe_table) { 511 alloc_probe_table[(size - 1) >> shift] = 512 array[i].kc_alloc_probe_id; 513 } 514 if (free_probe_table) { 515 free_probe_table[(size - 1) >> shift] = 516 array[i].kc_free_probe_id; 517 } 518 #endif 519 size += table_unit; 520 } 521 } 522 return maxidx; 523 } 524 525 void 526 kmem_init(void) 527 { 528 kmem_cache_maxidx = kmem_create_caches(kmem_cache_sizes, 529 kmem_cache_alloc_probe_id, kmem_cache_free_probe_id, 530 kmem_cache, KMEM_MAXSIZE, KMEM_SHIFT, IPL_VM); 531 kmem_cache_big_maxidx = kmem_create_caches(kmem_cache_big_sizes, 532 kmem_cache_big_alloc_probe_id, kmem_cache_big_free_probe_id, 533 kmem_cache_big, PAGE_SIZE, KMEM_BIG_SHIFT, IPL_VM); 534 } 535 536 size_t 537 kmem_roundup_size(size_t size) 538 { 539 return (size + (KMEM_ALIGN - 1)) & ~(KMEM_ALIGN - 1); 540 } 541 542 /* 543 * Used to dynamically allocate string with kmem accordingly to format. 544 */ 545 char * 546 kmem_asprintf(const char *fmt, ...) 547 { 548 int size __diagused, len; 549 va_list va; 550 char *str; 551 552 va_start(va, fmt); 553 len = vsnprintf(NULL, 0, fmt, va); 554 va_end(va); 555 556 str = kmem_alloc(len + 1, KM_SLEEP); 557 558 va_start(va, fmt); 559 size = vsnprintf(str, len + 1, fmt, va); 560 va_end(va); 561 562 KASSERT(size == len); 563 564 return str; 565 } 566 567 char * 568 kmem_strdupsize(const char *str, size_t *lenp, km_flag_t flags) 569 { 570 size_t len = strlen(str) + 1; 571 char *ptr = kmem_alloc(len, flags); 572 if (ptr == NULL) 573 return NULL; 574 575 if (lenp) 576 *lenp = len; 577 memcpy(ptr, str, len); 578 return ptr; 579 } 580 581 char * 582 kmem_strndup(const char *str, size_t maxlen, km_flag_t flags) 583 { 584 KASSERT(str != NULL); 585 KASSERT(maxlen != 0); 586 587 size_t len = strnlen(str, maxlen); 588 char *ptr = kmem_alloc(len + 1, flags); 589 if (ptr == NULL) 590 return NULL; 591 592 memcpy(ptr, str, len); 593 ptr[len] = '\0'; 594 595 return ptr; 596 } 597 598 void 599 kmem_strfree(char *str) 600 { 601 if (str == NULL) 602 return; 603 604 kmem_free(str, strlen(str) + 1); 605 } 606 607 /* 608 * Utility routine to maybe-allocate a temporary buffer if the size 609 * is larger than we're willing to put on the stack. 610 */ 611 void * 612 kmem_tmpbuf_alloc(size_t size, void *stackbuf, size_t stackbufsize, 613 km_flag_t flags) 614 { 615 if (size <= stackbufsize) { 616 return stackbuf; 617 } 618 619 return kmem_alloc(size, flags); 620 } 621 622 void 623 kmem_tmpbuf_free(void *buf, size_t size, void *stackbuf) 624 { 625 if (buf != stackbuf) { 626 kmem_free(buf, size); 627 } 628 } 629 630 /* --------------------------- DEBUG / DIAGNOSTIC --------------------------- */ 631 632 #if defined(KMEM_SIZE) 633 static void 634 kmem_size_set(void *p, size_t sz) 635 { 636 memcpy((char *)p + sz, &sz, sizeof(size_t)); 637 } 638 639 static void 640 kmem_size_check(void *p, size_t sz) 641 { 642 size_t hsz; 643 644 memcpy(&hsz, (char *)p + sz, sizeof(size_t)); 645 646 if (hsz != sz) { 647 panic("kmem_free(%p, %zu) != allocated size %zu; overwrote?", 648 p, sz, hsz); 649 } 650 651 memset((char *)p + sz, 0xff, sizeof(size_t)); 652 } 653 #endif /* defined(KMEM_SIZE) */ 654
Indexes created Sat Sep 20 22:09:52 GMT 2025