1 /*- 2 * SPDX-License-Identifier: (BSD-3-Clause AND MIT-CMU) 3 * 4 * Copyright (c) 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * The Mach Operating System project at Carnegie-Mellon University. 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 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * 35 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 36 * All rights reserved. 37 * 38 * Permission to use, copy, modify and distribute this software and 39 * its documentation is hereby granted, provided that both the copyright 40 * notice and this permission notice appear in all copies of the 41 * software, derivative works or modified versions, and any portions 42 * thereof, and that both notices appear in supporting documentation. 43 * 44 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 45 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 46 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 47 * 48 * Carnegie Mellon requests users of this software to return to 49 * 50 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 51 * School of Computer Science 52 * Carnegie Mellon University 53 * Pittsburgh PA 15213-3890 54 * 55 * any improvements or extensions that they make and grant Carnegie the 56 * rights to redistribute these changes. 57 */ 58 59 #include <sys/cdefs.h> 60 #include "opt_vm.h" 61 #include "opt_kstack_pages.h" 62 #include "opt_kstack_max_pages.h" 63 #include "opt_kstack_usage_prof.h" 64 65 #include <sys/param.h> 66 #include <sys/systm.h> 67 #include <sys/asan.h> 68 #include <sys/domainset.h> 69 #include <sys/limits.h> 70 #include <sys/lock.h> 71 #include <sys/malloc.h> 72 #include <sys/msan.h> 73 #include <sys/mutex.h> 74 #include <sys/proc.h> 75 #include <sys/racct.h> 76 #include <sys/refcount.h> 77 #include <sys/resourcevar.h> 78 #include <sys/rwlock.h> 79 #include <sys/sched.h> 80 #include <sys/sf_buf.h> 81 #include <sys/shm.h> 82 #include <sys/smp.h> 83 #include <sys/vmmeter.h> 84 #include <sys/vmem.h> 85 #include <sys/sx.h> 86 #include <sys/sysctl.h> 87 #include <sys/kernel.h> 88 #include <sys/ktr.h> 89 #include <sys/unistd.h> 90 91 #include <vm/uma.h> 92 #include <vm/vm.h> 93 #include <vm/vm_param.h> 94 #include <vm/pmap.h> 95 #include <vm/vm_domainset.h> 96 #include <vm/vm_map.h> 97 #include <vm/vm_page.h> 98 #include <vm/vm_pageout.h> 99 #include <vm/vm_pagequeue.h> 100 #include <vm/vm_object.h> 101 #include <vm/vm_kern.h> 102 #include <vm/vm_extern.h> 103 #include <vm/vm_pager.h> 104 #include <vm/swap_pager.h> 105 #include <vm/vm_phys.h> 106 107 #include <machine/cpu.h> 108 109 #if VM_NRESERVLEVEL > 1 110 #define KVA_KSTACK_QUANTUM_SHIFT (VM_LEVEL_1_ORDER + VM_LEVEL_0_ORDER + \ 111 PAGE_SHIFT) 112 #elif VM_NRESERVLEVEL > 0 113 #define KVA_KSTACK_QUANTUM_SHIFT (VM_LEVEL_0_ORDER + PAGE_SHIFT) 114 #else 115 #define KVA_KSTACK_QUANTUM_SHIFT (8 + PAGE_SHIFT) 116 #endif 117 #define KVA_KSTACK_QUANTUM (1ul << KVA_KSTACK_QUANTUM_SHIFT) 118 119 /* 120 * MPSAFE 121 * 122 * WARNING! This code calls vm_map_check_protection() which only checks 123 * the associated vm_map_entry range. It does not determine whether the 124 * contents of the memory is actually readable or writable. In most cases 125 * just checking the vm_map_entry is sufficient within the kernel's address 126 * space. 127 */ 128 bool 129 kernacc(void *addr, int len, int rw) 130 { 131 boolean_t rv; 132 vm_offset_t saddr, eaddr; 133 vm_prot_t prot; 134 135 KASSERT((rw & ~VM_PROT_ALL) == 0, 136 ("illegal ``rw'' argument to kernacc (%x)\n", rw)); 137 138 if ((vm_offset_t)addr + len > vm_map_max(kernel_map) || 139 (vm_offset_t)addr + len < (vm_offset_t)addr) 140 return (false); 141 142 prot = rw; 143 saddr = trunc_page((vm_offset_t)addr); 144 eaddr = round_page((vm_offset_t)addr + len); 145 vm_map_lock_read(kernel_map); 146 rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot); 147 vm_map_unlock_read(kernel_map); 148 return (rv == TRUE); 149 } 150 151 /* 152 * MPSAFE 153 * 154 * WARNING! This code calls vm_map_check_protection() which only checks 155 * the associated vm_map_entry range. It does not determine whether the 156 * contents of the memory is actually readable or writable. vmapbuf(), 157 * vm_fault_quick(), or copyin()/copout()/su*()/fu*() functions should be 158 * used in conjunction with this call. 159 */ 160 bool 161 useracc(void *addr, int len, int rw) 162 { 163 boolean_t rv; 164 vm_prot_t prot; 165 vm_map_t map; 166 167 KASSERT((rw & ~VM_PROT_ALL) == 0, 168 ("illegal ``rw'' argument to useracc (%x)\n", rw)); 169 prot = rw; 170 map = &curproc->p_vmspace->vm_map; 171 if ((vm_offset_t)addr + len > vm_map_max(map) || 172 (vm_offset_t)addr + len < (vm_offset_t)addr) { 173 return (false); 174 } 175 vm_map_lock_read(map); 176 rv = vm_map_check_protection(map, trunc_page((vm_offset_t)addr), 177 round_page((vm_offset_t)addr + len), prot); 178 vm_map_unlock_read(map); 179 return (rv == TRUE); 180 } 181 182 int 183 vslock(void *addr, size_t len) 184 { 185 vm_offset_t end, last, start; 186 vm_size_t npages; 187 int error; 188 189 last = (vm_offset_t)addr + len; 190 start = trunc_page((vm_offset_t)addr); 191 end = round_page(last); 192 if (last < (vm_offset_t)addr || end < (vm_offset_t)addr) 193 return (EINVAL); 194 npages = atop(end - start); 195 if (npages > vm_page_max_user_wired) 196 return (ENOMEM); 197 error = vm_map_wire(&curproc->p_vmspace->vm_map, start, end, 198 VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES); 199 if (error == KERN_SUCCESS) { 200 curthread->td_vslock_sz += len; 201 return (0); 202 } 203 204 /* 205 * Return EFAULT on error to match copy{in,out}() behaviour 206 * rather than returning ENOMEM like mlock() would. 207 */ 208 return (EFAULT); 209 } 210 211 void 212 vsunlock(void *addr, size_t len) 213 { 214 215 /* Rely on the parameter sanity checks performed by vslock(). */ 216 MPASS(curthread->td_vslock_sz >= len); 217 curthread->td_vslock_sz -= len; 218 (void)vm_map_unwire(&curproc->p_vmspace->vm_map, 219 trunc_page((vm_offset_t)addr), round_page((vm_offset_t)addr + len), 220 VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES); 221 } 222 223 /* 224 * Pin the page contained within the given object at the given offset. If the 225 * page is not resident, allocate and load it using the given object's pager. 226 * Return the pinned page if successful; otherwise, return NULL. 227 */ 228 static vm_page_t 229 vm_imgact_hold_page(vm_object_t object, vm_ooffset_t offset) 230 { 231 vm_page_t m; 232 vm_pindex_t pindex; 233 234 pindex = OFF_TO_IDX(offset); 235 (void)vm_page_grab_valid_unlocked(&m, object, pindex, 236 VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED); 237 return (m); 238 } 239 240 /* 241 * Return a CPU private mapping to the page at the given offset within the 242 * given object. The page is pinned before it is mapped. 243 */ 244 struct sf_buf * 245 vm_imgact_map_page(vm_object_t object, vm_ooffset_t offset) 246 { 247 vm_page_t m; 248 249 m = vm_imgact_hold_page(object, offset); 250 if (m == NULL) 251 return (NULL); 252 sched_pin(); 253 return (sf_buf_alloc(m, SFB_CPUPRIVATE)); 254 } 255 256 /* 257 * Destroy the given CPU private mapping and unpin the page that it mapped. 258 */ 259 void 260 vm_imgact_unmap_page(struct sf_buf *sf) 261 { 262 vm_page_t m; 263 264 m = sf_buf_page(sf); 265 sf_buf_free(sf); 266 sched_unpin(); 267 vm_page_unwire(m, PQ_ACTIVE); 268 } 269 270 void 271 vm_sync_icache(vm_map_t map, vm_offset_t va, vm_offset_t sz) 272 { 273 274 pmap_sync_icache(map->pmap, va, sz); 275 } 276 277 static vm_object_t kstack_object; 278 static vm_object_t kstack_alt_object; 279 static uma_zone_t kstack_cache; 280 static int kstack_cache_size; 281 static vmem_t *vmd_kstack_arena[MAXMEMDOM]; 282 283 static int 284 sysctl_kstack_cache_size(SYSCTL_HANDLER_ARGS) 285 { 286 int error, oldsize; 287 288 oldsize = kstack_cache_size; 289 error = sysctl_handle_int(oidp, arg1, arg2, req); 290 if (error == 0 && req->newptr && oldsize != kstack_cache_size) 291 uma_zone_set_maxcache(kstack_cache, kstack_cache_size); 292 return (error); 293 } 294 SYSCTL_PROC(_vm, OID_AUTO, kstack_cache_size, 295 CTLTYPE_INT|CTLFLAG_MPSAFE|CTLFLAG_RW, &kstack_cache_size, 0, 296 sysctl_kstack_cache_size, "IU", "Maximum number of cached kernel stacks"); 297 298 /* 299 * Allocate a virtual address range from a domain kstack arena, following 300 * the specified NUMA policy. 301 */ 302 static vm_offset_t 303 vm_thread_alloc_kstack_kva(vm_size_t size, int domain) 304 { 305 #ifndef __ILP32__ 306 int rv; 307 vmem_t *arena; 308 vm_offset_t addr = 0; 309 310 size = round_page(size); 311 /* Allocate from the kernel arena for non-standard kstack sizes. */ 312 if (size != ptoa(kstack_pages + KSTACK_GUARD_PAGES)) { 313 arena = vm_dom[domain].vmd_kernel_arena; 314 } else { 315 arena = vmd_kstack_arena[domain]; 316 } 317 rv = vmem_alloc(arena, size, M_BESTFIT | M_NOWAIT, &addr); 318 if (rv == ENOMEM) 319 return (0); 320 KASSERT(atop(addr - VM_MIN_KERNEL_ADDRESS) % 321 (kstack_pages + KSTACK_GUARD_PAGES) == 0, 322 ("%s: allocated kstack KVA not aligned to multiple of kstack size", 323 __func__)); 324 325 return (addr); 326 #else 327 return (kva_alloc(size)); 328 #endif 329 } 330 331 /* 332 * Release a region of kernel virtual memory 333 * allocated from the kstack arena. 334 */ 335 static __noinline void 336 vm_thread_free_kstack_kva(vm_offset_t addr, vm_size_t size, int domain) 337 { 338 vmem_t *arena; 339 340 size = round_page(size); 341 #ifdef __ILP32__ 342 arena = kernel_arena; 343 #else 344 arena = vmd_kstack_arena[domain]; 345 if (size != ptoa(kstack_pages + KSTACK_GUARD_PAGES)) { 346 arena = vm_dom[domain].vmd_kernel_arena; 347 } 348 #endif 349 vmem_free(arena, addr, size); 350 } 351 352 static vmem_size_t 353 vm_thread_kstack_import_quantum(void) 354 { 355 #ifndef __ILP32__ 356 /* 357 * The kstack_quantum is larger than KVA_QUANTUM to account 358 * for holes induced by guard pages. 359 */ 360 return (KVA_KSTACK_QUANTUM * (kstack_pages + KSTACK_GUARD_PAGES)); 361 #else 362 return (KVA_KSTACK_QUANTUM); 363 #endif 364 } 365 366 /* 367 * Import KVA from a parent arena into the kstack arena. Imports must be 368 * a multiple of kernel stack pages + guard pages in size. 369 * 370 * Kstack VA allocations need to be aligned so that the linear KVA pindex 371 * is divisible by the total number of kstack VA pages. This is necessary to 372 * make vm_kstack_pindex work properly. 373 * 374 * We import a multiple of KVA_KSTACK_QUANTUM-sized region from the parent 375 * arena. The actual size used by the kstack arena is one kstack smaller to 376 * allow for the necessary alignment adjustments to be made. 377 */ 378 static int 379 vm_thread_kstack_arena_import(void *arena, vmem_size_t size, int flags, 380 vmem_addr_t *addrp) 381 { 382 int error, rem; 383 size_t kpages = kstack_pages + KSTACK_GUARD_PAGES; 384 385 KASSERT(atop(size) % kpages == 0, 386 ("%s: Size %jd is not a multiple of kstack pages (%d)", __func__, 387 (intmax_t)size, (int)kpages)); 388 389 error = vmem_xalloc(arena, vm_thread_kstack_import_quantum(), 390 KVA_KSTACK_QUANTUM, 0, 0, VMEM_ADDR_MIN, VMEM_ADDR_MAX, flags, 391 addrp); 392 if (error) { 393 return (error); 394 } 395 396 rem = atop(*addrp - VM_MIN_KERNEL_ADDRESS) % kpages; 397 if (rem != 0) { 398 /* Bump addr to next aligned address */ 399 *addrp = *addrp + (kpages - rem) * PAGE_SIZE; 400 } 401 402 return (0); 403 } 404 405 /* 406 * Release KVA from a parent arena into the kstack arena. Released imports must 407 * be a multiple of kernel stack pages + guard pages in size. 408 */ 409 static void 410 vm_thread_kstack_arena_release(void *arena, vmem_addr_t addr, vmem_size_t size) 411 { 412 int rem; 413 size_t kpages __diagused = kstack_pages + KSTACK_GUARD_PAGES; 414 415 KASSERT(size % kpages == 0, 416 ("%s: Size %jd is not a multiple of kstack pages (%d)", __func__, 417 (intmax_t)size, (int)kpages)); 418 419 KASSERT((addr - VM_MIN_KERNEL_ADDRESS) % kpages == 0, 420 ("%s: Address %p is not properly aligned (%p)", __func__, 421 (void *)addr, (void *)VM_MIN_KERNEL_ADDRESS)); 422 /* 423 * If the address is not KVA_KSTACK_QUANTUM-aligned we have to decrement 424 * it to account for the shift in kva_import_kstack. 425 */ 426 rem = addr % KVA_KSTACK_QUANTUM; 427 if (rem) { 428 KASSERT(rem <= ptoa(kpages), 429 ("%s: rem > kpages (%d), (%d)", __func__, rem, 430 (int)kpages)); 431 addr -= rem; 432 } 433 vmem_xfree(arena, addr, vm_thread_kstack_import_quantum()); 434 } 435 436 /* 437 * Create the kernel stack for a new thread. 438 */ 439 static vm_offset_t 440 vm_thread_stack_create(struct domainset *ds, int pages) 441 { 442 vm_page_t ma[KSTACK_MAX_PAGES]; 443 struct vm_domainset_iter di; 444 int req = VM_ALLOC_NORMAL; 445 vm_object_t obj; 446 vm_offset_t ks; 447 int domain, i; 448 449 obj = vm_thread_kstack_size_to_obj(pages); 450 if (vm_ndomains > 1) 451 obj->domain.dr_policy = ds; 452 vm_domainset_iter_page_init(&di, obj, 0, &domain, &req); 453 do { 454 /* 455 * Get a kernel virtual address for this thread's kstack. 456 */ 457 ks = vm_thread_alloc_kstack_kva(ptoa(pages + KSTACK_GUARD_PAGES), 458 domain); 459 if (ks == 0) 460 continue; 461 ks += ptoa(KSTACK_GUARD_PAGES); 462 463 /* 464 * Allocate physical pages to back the stack. 465 */ 466 if (vm_thread_stack_back(ks, ma, pages, req, domain) != 0) { 467 vm_thread_free_kstack_kva(ks - ptoa(KSTACK_GUARD_PAGES), 468 ptoa(pages + KSTACK_GUARD_PAGES), domain); 469 continue; 470 } 471 if (KSTACK_GUARD_PAGES != 0) { 472 pmap_qremove(ks - ptoa(KSTACK_GUARD_PAGES), 473 KSTACK_GUARD_PAGES); 474 } 475 for (i = 0; i < pages; i++) 476 vm_page_valid(ma[i]); 477 pmap_qenter(ks, ma, pages); 478 return (ks); 479 } while (vm_domainset_iter_page(&di, obj, &domain) == 0); 480 481 return (0); 482 } 483 484 static __noinline void 485 vm_thread_stack_dispose(vm_offset_t ks, int pages) 486 { 487 vm_page_t m; 488 vm_pindex_t pindex; 489 int i, domain; 490 vm_object_t obj = vm_thread_kstack_size_to_obj(pages); 491 492 pindex = vm_kstack_pindex(ks, pages); 493 domain = vm_phys_domain(vtophys(ks)); 494 pmap_qremove(ks, pages); 495 VM_OBJECT_WLOCK(obj); 496 for (i = 0; i < pages; i++) { 497 m = vm_page_lookup(obj, pindex + i); 498 if (m == NULL) 499 panic("%s: kstack already missing?", __func__); 500 KASSERT(vm_page_domain(m) == domain, 501 ("%s: page %p domain mismatch, expected %d got %d", 502 __func__, m, domain, vm_page_domain(m))); 503 vm_page_xbusy_claim(m); 504 vm_page_unwire_noq(m); 505 vm_page_free(m); 506 } 507 VM_OBJECT_WUNLOCK(obj); 508 kasan_mark((void *)ks, ptoa(pages), ptoa(pages), 0); 509 vm_thread_free_kstack_kva(ks - (KSTACK_GUARD_PAGES * PAGE_SIZE), 510 ptoa(pages + KSTACK_GUARD_PAGES), domain); 511 } 512 513 /* 514 * Allocate the kernel stack for a new thread. 515 */ 516 int 517 vm_thread_new(struct thread *td, int pages) 518 { 519 vm_offset_t ks; 520 u_short ks_domain; 521 522 /* Bounds check */ 523 if (pages <= 1) 524 pages = kstack_pages; 525 else if (pages > KSTACK_MAX_PAGES) 526 pages = KSTACK_MAX_PAGES; 527 528 ks = 0; 529 if (pages == kstack_pages && kstack_cache != NULL) 530 ks = (vm_offset_t)uma_zalloc(kstack_cache, M_NOWAIT); 531 532 /* 533 * Ensure that kstack objects can draw pages from any memory 534 * domain. Otherwise a local memory shortage can block a process 535 * swap-in. 536 */ 537 if (ks == 0) 538 ks = vm_thread_stack_create(DOMAINSET_PREF(PCPU_GET(domain)), 539 pages); 540 if (ks == 0) 541 return (0); 542 543 ks_domain = vm_phys_domain(vtophys(ks)); 544 KASSERT(ks_domain >= 0 && ks_domain < vm_ndomains, 545 ("%s: invalid domain for kstack %p", __func__, (void *)ks)); 546 td->td_kstack = ks; 547 td->td_kstack_pages = pages; 548 td->td_kstack_domain = ks_domain; 549 return (1); 550 } 551 552 /* 553 * Dispose of a thread's kernel stack. 554 */ 555 void 556 vm_thread_dispose(struct thread *td) 557 { 558 vm_offset_t ks; 559 int pages; 560 561 pages = td->td_kstack_pages; 562 ks = td->td_kstack; 563 td->td_kstack = 0; 564 td->td_kstack_pages = 0; 565 td->td_kstack_domain = MAXMEMDOM; 566 if (pages == kstack_pages) { 567 kasan_mark((void *)ks, 0, ptoa(pages), KASAN_KSTACK_FREED); 568 uma_zfree(kstack_cache, (void *)ks); 569 } else { 570 vm_thread_stack_dispose(ks, pages); 571 } 572 } 573 574 /* 575 * Calculate kstack pindex. 576 * 577 * Uses a non-identity mapping if guard pages are 578 * active to avoid pindex holes in the kstack object. 579 */ 580 vm_pindex_t 581 vm_kstack_pindex(vm_offset_t ks, int kpages) 582 { 583 vm_pindex_t pindex = atop(ks - VM_MIN_KERNEL_ADDRESS); 584 585 #ifdef __ILP32__ 586 return (pindex); 587 #else 588 /* 589 * Return the linear pindex if guard pages aren't active or if we are 590 * allocating a non-standard kstack size. 591 */ 592 if (KSTACK_GUARD_PAGES == 0 || kpages != kstack_pages) { 593 return (pindex); 594 } 595 KASSERT(pindex % (kpages + KSTACK_GUARD_PAGES) >= KSTACK_GUARD_PAGES, 596 ("%s: Attempting to calculate kstack guard page pindex", __func__)); 597 598 return (pindex - 599 (pindex / (kpages + KSTACK_GUARD_PAGES) + 1) * KSTACK_GUARD_PAGES); 600 #endif 601 } 602 603 /* 604 * Allocate physical pages, following the specified NUMA policy, to back a 605 * kernel stack. 606 */ 607 int 608 vm_thread_stack_back(vm_offset_t ks, vm_page_t ma[], int npages, int req_class, 609 int domain) 610 { 611 vm_object_t obj = vm_thread_kstack_size_to_obj(npages); 612 vm_pindex_t pindex; 613 vm_page_t m; 614 int n; 615 616 pindex = vm_kstack_pindex(ks, npages); 617 618 VM_OBJECT_WLOCK(obj); 619 for (n = 0; n < npages;) { 620 m = vm_page_grab(obj, pindex + n, 621 VM_ALLOC_NOCREAT | VM_ALLOC_WIRED); 622 if (m == NULL) { 623 m = vm_page_alloc_domain(obj, pindex + n, domain, 624 req_class | VM_ALLOC_WIRED); 625 } 626 if (m == NULL) 627 break; 628 ma[n++] = m; 629 } 630 if (n < npages) 631 goto cleanup; 632 VM_OBJECT_WUNLOCK(obj); 633 634 return (0); 635 cleanup: 636 for (int i = 0; i < n; i++) { 637 m = ma[i]; 638 (void)vm_page_unwire_noq(m); 639 vm_page_free(m); 640 } 641 VM_OBJECT_WUNLOCK(obj); 642 643 return (ENOMEM); 644 } 645 646 vm_object_t 647 vm_thread_kstack_size_to_obj(int npages) 648 { 649 return (npages == kstack_pages ? kstack_object : kstack_alt_object); 650 } 651 652 static int 653 kstack_import(void *arg, void **store, int cnt, int domain, int flags) 654 { 655 struct domainset *ds; 656 int i; 657 658 if (domain == UMA_ANYDOMAIN) 659 ds = DOMAINSET_RR(); 660 else 661 ds = DOMAINSET_PREF(domain); 662 663 for (i = 0; i < cnt; i++) { 664 store[i] = (void *)vm_thread_stack_create(ds, kstack_pages); 665 if (store[i] == NULL) 666 break; 667 } 668 return (i); 669 } 670 671 static void 672 kstack_release(void *arg, void **store, int cnt) 673 { 674 vm_offset_t ks; 675 int i; 676 677 for (i = 0; i < cnt; i++) { 678 ks = (vm_offset_t)store[i]; 679 vm_thread_stack_dispose(ks, kstack_pages); 680 } 681 } 682 683 static void 684 kstack_cache_init(void *null) 685 { 686 vm_size_t kstack_quantum; 687 int domain; 688 689 kstack_object = vm_object_allocate(OBJT_SWAP, 690 atop(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS)); 691 kstack_cache = uma_zcache_create("kstack_cache", 692 kstack_pages * PAGE_SIZE, NULL, NULL, NULL, NULL, 693 kstack_import, kstack_release, NULL, 694 UMA_ZONE_FIRSTTOUCH); 695 kstack_cache_size = imax(128, mp_ncpus * 4); 696 uma_zone_set_maxcache(kstack_cache, kstack_cache_size); 697 698 kstack_alt_object = vm_object_allocate(OBJT_SWAP, 699 atop(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS)); 700 701 kstack_quantum = vm_thread_kstack_import_quantum(); 702 /* 703 * Reduce size used by the kstack arena to allow for 704 * alignment adjustments in vm_thread_kstack_arena_import. 705 */ 706 kstack_quantum -= (kstack_pages + KSTACK_GUARD_PAGES) * PAGE_SIZE; 707 /* 708 * Create the kstack_arena for each domain and set kernel_arena as 709 * parent. 710 */ 711 for (domain = 0; domain < vm_ndomains; domain++) { 712 vmd_kstack_arena[domain] = vmem_create("kstack arena", 0, 0, 713 PAGE_SIZE, 0, M_WAITOK); 714 KASSERT(vmd_kstack_arena[domain] != NULL, 715 ("%s: failed to create domain %d kstack_arena", __func__, 716 domain)); 717 vmem_set_import(vmd_kstack_arena[domain], 718 vm_thread_kstack_arena_import, 719 vm_thread_kstack_arena_release, 720 vm_dom[domain].vmd_kernel_arena, kstack_quantum); 721 } 722 } 723 SYSINIT(vm_kstacks, SI_SUB_KMEM, SI_ORDER_ANY, kstack_cache_init, NULL); 724 725 #ifdef KSTACK_USAGE_PROF 726 /* 727 * Track maximum stack used by a thread in kernel. 728 */ 729 static int max_kstack_used; 730 731 SYSCTL_INT(_debug, OID_AUTO, max_kstack_used, CTLFLAG_RD, 732 &max_kstack_used, 0, 733 "Maximum stack depth used by a thread in kernel"); 734 735 void 736 intr_prof_stack_use(struct thread *td, struct trapframe *frame) 737 { 738 vm_offset_t stack_top; 739 vm_offset_t current; 740 int used, prev_used; 741 742 /* 743 * Testing for interrupted kernel mode isn't strictly 744 * needed. It optimizes the execution, since interrupts from 745 * usermode will have only the trap frame on the stack. 746 */ 747 if (TRAPF_USERMODE(frame)) 748 return; 749 750 stack_top = td->td_kstack + td->td_kstack_pages * PAGE_SIZE; 751 current = (vm_offset_t)(uintptr_t)&stack_top; 752 753 /* 754 * Try to detect if interrupt is using kernel thread stack. 755 * Hardware could use a dedicated stack for interrupt handling. 756 */ 757 if (stack_top <= current || current < td->td_kstack) 758 return; 759 760 used = stack_top - current; 761 for (;;) { 762 prev_used = max_kstack_used; 763 if (prev_used >= used) 764 break; 765 if (atomic_cmpset_int(&max_kstack_used, prev_used, used)) 766 break; 767 } 768 } 769 #endif /* KSTACK_USAGE_PROF */ 770 771 /* 772 * Implement fork's actions on an address space. 773 * Here we arrange for the address space to be copied or referenced, 774 * allocate a user struct (pcb and kernel stack), then call the 775 * machine-dependent layer to fill those in and make the new process 776 * ready to run. The new process is set up so that it returns directly 777 * to user mode to avoid stack copying and relocation problems. 778 */ 779 int 780 vm_forkproc(struct thread *td, struct proc *p2, struct thread *td2, 781 struct vmspace *vm2, int flags) 782 { 783 struct proc *p1 = td->td_proc; 784 struct domainset *dset; 785 int error; 786 787 if ((flags & RFPROC) == 0) { 788 /* 789 * Divorce the memory, if it is shared, essentially 790 * this changes shared memory amongst threads, into 791 * COW locally. 792 */ 793 if ((flags & RFMEM) == 0) { 794 error = vmspace_unshare(p1); 795 if (error) 796 return (error); 797 } 798 cpu_fork(td, p2, td2, flags); 799 return (0); 800 } 801 802 if (flags & RFMEM) { 803 p2->p_vmspace = p1->p_vmspace; 804 refcount_acquire(&p1->p_vmspace->vm_refcnt); 805 } 806 dset = td2->td_domain.dr_policy; 807 while (vm_page_count_severe_set(&dset->ds_mask)) { 808 vm_wait_doms(&dset->ds_mask, 0); 809 } 810 811 if ((flags & RFMEM) == 0) { 812 p2->p_vmspace = vm2; 813 if (p1->p_vmspace->vm_shm) 814 shmfork(p1, p2); 815 } 816 817 /* 818 * cpu_fork will copy and update the pcb, set up the kernel stack, 819 * and make the child ready to run. 820 */ 821 cpu_fork(td, p2, td2, flags); 822 return (0); 823 } 824 825 /* 826 * Called after process has been wait(2)'ed upon and is being reaped. 827 * The idea is to reclaim resources that we could not reclaim while 828 * the process was still executing. 829 */ 830 void 831 vm_waitproc(struct proc *p) 832 { 833 834 vmspace_exitfree(p); /* and clean-out the vmspace */ 835 } 836 837 void 838 kick_proc0(void) 839 { 840 841 wakeup(&proc0); 842 } 843