1 /* $OpenBSD: kern_malloc.c,v 1.6 1996/06/20 10:53:06 deraadt Exp $ */ 2 /* $NetBSD: kern_malloc.c,v 1.15.4.2 1996/06/13 17:10:56 cgd Exp $ */ 3 4 /* 5 * Copyright (c) 1987, 1991, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)kern_malloc.c 8.3 (Berkeley) 1/4/94 37 */ 38 39 #include <sys/param.h> 40 #include <sys/proc.h> 41 #include <sys/map.h> 42 #include <sys/kernel.h> 43 #include <sys/malloc.h> 44 #include <sys/systm.h> 45 46 #include <vm/vm.h> 47 #include <vm/vm_kern.h> 48 49 struct kmembuckets bucket[MINBUCKET + 16]; 50 struct kmemstats kmemstats[M_LAST]; 51 struct kmemusage *kmemusage; 52 char *kmembase, *kmemlimit; 53 char *memname[] = INITKMEMNAMES; 54 55 #ifdef DIAGNOSTIC 56 /* 57 * This structure provides a set of masks to catch unaligned frees. 58 */ 59 long addrmask[] = { 0, 60 0x00000001, 0x00000003, 0x00000007, 0x0000000f, 61 0x0000001f, 0x0000003f, 0x0000007f, 0x000000ff, 62 0x000001ff, 0x000003ff, 0x000007ff, 0x00000fff, 63 0x00001fff, 0x00003fff, 0x00007fff, 0x0000ffff, 64 }; 65 66 /* 67 * The WEIRD_ADDR is used as known text to copy into free objects so 68 * that modifications after frees can be detected. 69 */ 70 #define WEIRD_ADDR ((unsigned) 0xdeadbeef) 71 #define MAX_COPY 32 72 73 /* 74 * Normally the freelist structure is used only to hold the list pointer 75 * for free objects. However, when running with diagnostics, the first 76 * 8 bytes of the structure is unused except for diagnostic information, 77 * and the free list pointer is at offst 8 in the structure. Since the 78 * first 8 bytes is the portion of the structure most often modified, this 79 * helps to detect memory reuse problems and avoid free list corruption. 80 */ 81 struct freelist { 82 int32_t spare0; 83 int16_t type; 84 int16_t spare1; 85 caddr_t next; 86 }; 87 #else /* !DIAGNOSTIC */ 88 struct freelist { 89 caddr_t next; 90 }; 91 #endif /* DIAGNOSTIC */ 92 93 /* 94 * Allocate a block of memory 95 */ 96 void * 97 malloc(size, type, flags) 98 unsigned long size; 99 int type, flags; 100 { 101 register struct kmembuckets *kbp; 102 register struct kmemusage *kup; 103 register struct freelist *freep; 104 long indx, npg, allocsize; 105 int s; 106 caddr_t va, cp, savedlist; 107 #ifdef DIAGNOSTIC 108 int32_t *end, *lp; 109 int copysize; 110 char *savedtype; 111 #endif 112 #ifdef KMEMSTATS 113 register struct kmemstats *ksp = &kmemstats[type]; 114 115 if (((unsigned long)type) > M_LAST) 116 panic("malloc - bogus type"); 117 #endif 118 indx = BUCKETINDX(size); 119 kbp = &bucket[indx]; 120 s = splimp(); 121 #ifdef KMEMSTATS 122 while (ksp->ks_memuse >= ksp->ks_limit) { 123 if (flags & M_NOWAIT) { 124 splx(s); 125 return ((void *) NULL); 126 } 127 if (ksp->ks_limblocks < 65535) 128 ksp->ks_limblocks++; 129 tsleep((caddr_t)ksp, PSWP+2, memname[type], 0); 130 } 131 ksp->ks_size |= 1 << indx; 132 #endif 133 #ifdef DIAGNOSTIC 134 copysize = 1 << indx < MAX_COPY ? 1 << indx : MAX_COPY; 135 #endif 136 if (kbp->kb_next == NULL) { 137 kbp->kb_last = NULL; 138 if (size > MAXALLOCSAVE) 139 allocsize = roundup(size, CLBYTES); 140 else 141 allocsize = 1 << indx; 142 npg = clrnd(btoc(allocsize)); 143 va = (caddr_t) kmem_malloc(kmem_map, (vm_size_t)ctob(npg), 144 !(flags & M_NOWAIT)); 145 if (va == NULL) { 146 /* 147 * Kmem_malloc() can return NULL, even if it can 148 * wait, if there is no map space avaiable, because 149 * it can't fix that problem. Neither can we, 150 * right now. (We should release pages which 151 * are completely free and which are in buckets 152 * with too many free elements.) 153 */ 154 if ((flags & M_NOWAIT) == 0) 155 panic("malloc: out of space in kmem_map"); 156 splx(s); 157 return ((void *) NULL); 158 } 159 #ifdef KMEMSTATS 160 kbp->kb_total += kbp->kb_elmpercl; 161 #endif 162 kup = btokup(va); 163 kup->ku_indx = indx; 164 if (allocsize > MAXALLOCSAVE) { 165 if (npg > 65535) 166 panic("malloc: allocation too large"); 167 kup->ku_pagecnt = npg; 168 #ifdef KMEMSTATS 169 ksp->ks_memuse += allocsize; 170 #endif 171 goto out; 172 } 173 #ifdef KMEMSTATS 174 kup->ku_freecnt = kbp->kb_elmpercl; 175 kbp->kb_totalfree += kbp->kb_elmpercl; 176 #endif 177 /* 178 * Just in case we blocked while allocating memory, 179 * and someone else also allocated memory for this 180 * bucket, don't assume the list is still empty. 181 */ 182 savedlist = kbp->kb_next; 183 kbp->kb_next = cp = va + (npg * NBPG) - allocsize; 184 for (;;) { 185 freep = (struct freelist *)cp; 186 #ifdef DIAGNOSTIC 187 /* 188 * Copy in known text to detect modification 189 * after freeing. 190 */ 191 end = (int32_t *)&cp[copysize]; 192 for (lp = (int32_t *)cp; lp < end; lp++) 193 *lp = WEIRD_ADDR; 194 freep->type = M_FREE; 195 #endif /* DIAGNOSTIC */ 196 if (cp <= va) 197 break; 198 cp -= allocsize; 199 freep->next = cp; 200 } 201 freep->next = savedlist; 202 if (kbp->kb_last == NULL) 203 kbp->kb_last = (caddr_t)freep; 204 } 205 va = kbp->kb_next; 206 kbp->kb_next = ((struct freelist *)va)->next; 207 #ifdef DIAGNOSTIC 208 freep = (struct freelist *)va; 209 savedtype = (unsigned)freep->type < M_LAST ? 210 memname[freep->type] : "???"; 211 if (kbp->kb_next && 212 !kernacc(kbp->kb_next, sizeof(struct freelist), 0)) { 213 printf("%s %d of object %p size %ld %s %s (invalid addr %p)\n", 214 "Data modified on freelist: word", 215 (int32_t *)&kbp->kb_next - (int32_t *)kbp, va, size, 216 "previous type", savedtype, kbp->kb_next); 217 kbp->kb_next = NULL; 218 } 219 220 /* Fill the fields that we've used with WEIRD_ADDR */ 221 #if BYTE_ORDER == BIG_ENDIAN 222 freep->type = WEIRD_ADDR >> 16; 223 #endif 224 #if BYTE_ORDER == LITTLE_ENDIAN 225 freep->type = (short)WEIRD_ADDR; 226 #endif 227 end = (int32_t *)&freep->next + 228 (sizeof(freep->next) / sizeof(int32_t)); 229 for (lp = (int32_t *)&freep->next; lp < end; lp++) 230 *lp = WEIRD_ADDR; 231 232 /* and check that the data hasn't been modified. */ 233 end = (int32_t *)&va[copysize]; 234 for (lp = (int32_t *)va; lp < end; lp++) { 235 if (*lp == WEIRD_ADDR) 236 continue; 237 printf("%s %d of object %p size %ld %s %s (0x%x != 0x%x)\n", 238 "Data modified on freelist: word", lp - (int32_t *)va, 239 va, size, "previous type", savedtype, *lp, WEIRD_ADDR); 240 break; 241 } 242 243 freep->spare0 = 0; 244 #endif /* DIAGNOSTIC */ 245 #ifdef KMEMSTATS 246 kup = btokup(va); 247 if (kup->ku_indx != indx) 248 panic("malloc: wrong bucket"); 249 if (kup->ku_freecnt == 0) 250 panic("malloc: lost data"); 251 kup->ku_freecnt--; 252 kbp->kb_totalfree--; 253 ksp->ks_memuse += 1 << indx; 254 out: 255 kbp->kb_calls++; 256 ksp->ks_inuse++; 257 ksp->ks_calls++; 258 if (ksp->ks_memuse > ksp->ks_maxused) 259 ksp->ks_maxused = ksp->ks_memuse; 260 #else 261 out: 262 #endif 263 splx(s); 264 return ((void *) va); 265 } 266 267 /* 268 * Free a block of memory allocated by malloc. 269 */ 270 void 271 free(addr, type) 272 void *addr; 273 int type; 274 { 275 register struct kmembuckets *kbp; 276 register struct kmemusage *kup; 277 register struct freelist *freep; 278 long size; 279 int s; 280 #ifdef DIAGNOSTIC 281 caddr_t cp; 282 int32_t *end, *lp; 283 long alloc, copysize; 284 #endif 285 #ifdef KMEMSTATS 286 register struct kmemstats *ksp = &kmemstats[type]; 287 #endif 288 289 kup = btokup(addr); 290 size = 1 << kup->ku_indx; 291 kbp = &bucket[kup->ku_indx]; 292 s = splimp(); 293 #ifdef DIAGNOSTIC 294 /* 295 * Check for returns of data that do not point to the 296 * beginning of the allocation. 297 */ 298 if (size > NBPG * CLSIZE) 299 alloc = addrmask[BUCKETINDX(NBPG * CLSIZE)]; 300 else 301 alloc = addrmask[kup->ku_indx]; 302 if (((u_long)addr & alloc) != 0) 303 panic("free: unaligned addr %p, size %ld, type %s, mask %ld\n", 304 addr, size, memname[type], alloc); 305 #endif /* DIAGNOSTIC */ 306 if (size > MAXALLOCSAVE) { 307 kmem_free(kmem_map, (vm_offset_t)addr, ctob(kup->ku_pagecnt)); 308 #ifdef KMEMSTATS 309 size = kup->ku_pagecnt << PGSHIFT; 310 ksp->ks_memuse -= size; 311 kup->ku_indx = 0; 312 kup->ku_pagecnt = 0; 313 if (ksp->ks_memuse + size >= ksp->ks_limit && 314 ksp->ks_memuse < ksp->ks_limit) 315 wakeup((caddr_t)ksp); 316 ksp->ks_inuse--; 317 kbp->kb_total -= 1; 318 #endif 319 splx(s); 320 return; 321 } 322 freep = (struct freelist *)addr; 323 #ifdef DIAGNOSTIC 324 /* 325 * Check for multiple frees. Use a quick check to see if 326 * it looks free before laboriously searching the freelist. 327 */ 328 if (freep->spare0 == WEIRD_ADDR) { 329 for (cp = kbp->kb_next; cp; 330 cp = ((struct freelist *)cp)->next) { 331 if (addr != cp) 332 continue; 333 printf("multiply freed item %p\n", addr); 334 panic("free: duplicated free"); 335 } 336 } 337 /* 338 * Copy in known text to detect modification after freeing 339 * and to make it look free. Also, save the type being freed 340 * so we can list likely culprit if modification is detected 341 * when the object is reallocated. 342 */ 343 copysize = size < MAX_COPY ? size : MAX_COPY; 344 end = (int32_t *)&((caddr_t)addr)[copysize]; 345 for (lp = (int32_t *)addr; lp < end; lp++) 346 *lp = WEIRD_ADDR; 347 freep->type = type; 348 #endif /* DIAGNOSTIC */ 349 #ifdef KMEMSTATS 350 kup->ku_freecnt++; 351 if (kup->ku_freecnt >= kbp->kb_elmpercl) 352 if (kup->ku_freecnt > kbp->kb_elmpercl) 353 panic("free: multiple frees"); 354 else if (kbp->kb_totalfree > kbp->kb_highwat) 355 kbp->kb_couldfree++; 356 kbp->kb_totalfree++; 357 ksp->ks_memuse -= size; 358 if (ksp->ks_memuse + size >= ksp->ks_limit && 359 ksp->ks_memuse < ksp->ks_limit) 360 wakeup((caddr_t)ksp); 361 ksp->ks_inuse--; 362 #endif 363 if (kbp->kb_next == NULL) 364 kbp->kb_next = addr; 365 else 366 ((struct freelist *)kbp->kb_last)->next = addr; 367 freep->next = NULL; 368 kbp->kb_last = addr; 369 splx(s); 370 } 371 372 /* 373 * Initialize the kernel memory allocator 374 */ 375 void 376 kmeminit() 377 { 378 register long indx; 379 int npg; 380 381 #if ((MAXALLOCSAVE & (MAXALLOCSAVE - 1)) != 0) 382 ERROR!_kmeminit:_MAXALLOCSAVE_not_power_of_2 383 #endif 384 #if (MAXALLOCSAVE > MINALLOCSIZE * 32768) 385 ERROR!_kmeminit:_MAXALLOCSAVE_too_big 386 #endif 387 #if (MAXALLOCSAVE < CLBYTES) 388 ERROR!_kmeminit:_MAXALLOCSAVE_too_small 389 #endif 390 391 if (sizeof(struct freelist) > (1 << MINBUCKET)) 392 panic("minbucket too small/struct freelist too big"); 393 394 npg = VM_KMEM_SIZE/ NBPG; 395 kmemusage = (struct kmemusage *) kmem_alloc(kernel_map, 396 (vm_size_t)(npg * sizeof(struct kmemusage))); 397 kmem_map = kmem_suballoc(kernel_map, (vm_offset_t *)&kmembase, 398 (vm_offset_t *)&kmemlimit, (vm_size_t)(npg * NBPG), FALSE); 399 #ifdef KMEMSTATS 400 for (indx = 0; indx < MINBUCKET + 16; indx++) { 401 if (1 << indx >= CLBYTES) 402 bucket[indx].kb_elmpercl = 1; 403 else 404 bucket[indx].kb_elmpercl = CLBYTES / (1 << indx); 405 bucket[indx].kb_highwat = 5 * bucket[indx].kb_elmpercl; 406 } 407 for (indx = 0; indx < M_LAST; indx++) 408 kmemstats[indx].ks_limit = npg * NBPG * 6 / 10; 409 #endif 410 } 411