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 * from: @(#)vm_glue.c 8.6 (Berkeley) 1/5/94 35 * 36 * 37 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 38 * All rights reserved. 39 * 40 * Permission to use, copy, modify and distribute this software and 41 * its documentation is hereby granted, provided that both the copyright 42 * notice and this permission notice appear in all copies of the 43 * software, derivative works or modified versions, and any portions 44 * thereof, and that both notices appear in supporting documentation. 45 * 46 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 47 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 48 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 49 * 50 * Carnegie Mellon requests users of this software to return to 51 * 52 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 53 * School of Computer Science 54 * Carnegie Mellon University 55 * Pittsburgh PA 15213-3890 56 * 57 * any improvements or extensions that they make and grant Carnegie the 58 * rights to redistribute these changes. 59 */ 60 61 #include <sys/cdefs.h> 62 __FBSDID("$FreeBSD$"); 63 64 #include "opt_vm.h" 65 #include "opt_kstack_pages.h" 66 #include "opt_kstack_max_pages.h" 67 #include "opt_kstack_usage_prof.h" 68 69 #include <sys/param.h> 70 #include <sys/systm.h> 71 #include <sys/limits.h> 72 #include <sys/lock.h> 73 #include <sys/malloc.h> 74 #include <sys/mutex.h> 75 #include <sys/proc.h> 76 #include <sys/racct.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/vmmeter.h> 83 #include <sys/vmem.h> 84 #include <sys/sx.h> 85 #include <sys/sysctl.h> 86 #include <sys/_kstack_cache.h> 87 #include <sys/eventhandler.h> 88 #include <sys/kernel.h> 89 #include <sys/ktr.h> 90 #include <sys/unistd.h> 91 92 #include <vm/vm.h> 93 #include <vm/vm_param.h> 94 #include <vm/pmap.h> 95 #include <vm/vm_map.h> 96 #include <vm/vm_page.h> 97 #include <vm/vm_pageout.h> 98 #include <vm/vm_object.h> 99 #include <vm/vm_kern.h> 100 #include <vm/vm_extern.h> 101 #include <vm/vm_pager.h> 102 #include <vm/swap_pager.h> 103 104 #include <machine/cpu.h> 105 106 /* 107 * MPSAFE 108 * 109 * WARNING! This code calls vm_map_check_protection() which only checks 110 * the associated vm_map_entry range. It does not determine whether the 111 * contents of the memory is actually readable or writable. In most cases 112 * just checking the vm_map_entry is sufficient within the kernel's address 113 * space. 114 */ 115 int 116 kernacc(void *addr, int len, int rw) 117 { 118 boolean_t rv; 119 vm_offset_t saddr, eaddr; 120 vm_prot_t prot; 121 122 KASSERT((rw & ~VM_PROT_ALL) == 0, 123 ("illegal ``rw'' argument to kernacc (%x)\n", rw)); 124 125 if ((vm_offset_t)addr + len > kernel_map->max_offset || 126 (vm_offset_t)addr + len < (vm_offset_t)addr) 127 return (FALSE); 128 129 prot = rw; 130 saddr = trunc_page((vm_offset_t)addr); 131 eaddr = round_page((vm_offset_t)addr + len); 132 vm_map_lock_read(kernel_map); 133 rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot); 134 vm_map_unlock_read(kernel_map); 135 return (rv == TRUE); 136 } 137 138 /* 139 * MPSAFE 140 * 141 * WARNING! This code calls vm_map_check_protection() which only checks 142 * the associated vm_map_entry range. It does not determine whether the 143 * contents of the memory is actually readable or writable. vmapbuf(), 144 * vm_fault_quick(), or copyin()/copout()/su*()/fu*() functions should be 145 * used in conjunction with this call. 146 */ 147 int 148 useracc(void *addr, int len, int rw) 149 { 150 boolean_t rv; 151 vm_prot_t prot; 152 vm_map_t map; 153 154 KASSERT((rw & ~VM_PROT_ALL) == 0, 155 ("illegal ``rw'' argument to useracc (%x)\n", rw)); 156 prot = rw; 157 map = &curproc->p_vmspace->vm_map; 158 if ((vm_offset_t)addr + len > vm_map_max(map) || 159 (vm_offset_t)addr + len < (vm_offset_t)addr) { 160 return (FALSE); 161 } 162 vm_map_lock_read(map); 163 rv = vm_map_check_protection(map, trunc_page((vm_offset_t)addr), 164 round_page((vm_offset_t)addr + len), prot); 165 vm_map_unlock_read(map); 166 return (rv == TRUE); 167 } 168 169 int 170 vslock(void *addr, size_t len) 171 { 172 vm_offset_t end, last, start; 173 vm_size_t npages; 174 int error; 175 176 last = (vm_offset_t)addr + len; 177 start = trunc_page((vm_offset_t)addr); 178 end = round_page(last); 179 if (last < (vm_offset_t)addr || end < (vm_offset_t)addr) 180 return (EINVAL); 181 npages = atop(end - start); 182 if (npages > vm_page_max_wired) 183 return (ENOMEM); 184 #if 0 185 /* 186 * XXX - not yet 187 * 188 * The limit for transient usage of wired pages should be 189 * larger than for "permanent" wired pages (mlock()). 190 * 191 * Also, the sysctl code, which is the only present user 192 * of vslock(), does a hard loop on EAGAIN. 193 */ 194 if (npages + vm_wire_count() > vm_page_max_wired) 195 return (EAGAIN); 196 #endif 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 int rv; 234 235 VM_OBJECT_WLOCK(object); 236 pindex = OFF_TO_IDX(offset); 237 m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY); 238 if (m->valid != VM_PAGE_BITS_ALL) { 239 vm_page_xbusy(m); 240 rv = vm_pager_get_pages(object, &m, 1, NULL, NULL); 241 if (rv != VM_PAGER_OK) { 242 vm_page_lock(m); 243 vm_page_free(m); 244 vm_page_unlock(m); 245 m = NULL; 246 goto out; 247 } 248 vm_page_xunbusy(m); 249 } 250 vm_page_lock(m); 251 vm_page_hold(m); 252 vm_page_activate(m); 253 vm_page_unlock(m); 254 out: 255 VM_OBJECT_WUNLOCK(object); 256 return (m); 257 } 258 259 /* 260 * Return a CPU private mapping to the page at the given offset within the 261 * given object. The page is pinned before it is mapped. 262 */ 263 struct sf_buf * 264 vm_imgact_map_page(vm_object_t object, vm_ooffset_t offset) 265 { 266 vm_page_t m; 267 268 m = vm_imgact_hold_page(object, offset); 269 if (m == NULL) 270 return (NULL); 271 sched_pin(); 272 return (sf_buf_alloc(m, SFB_CPUPRIVATE)); 273 } 274 275 /* 276 * Destroy the given CPU private mapping and unpin the page that it mapped. 277 */ 278 void 279 vm_imgact_unmap_page(struct sf_buf *sf) 280 { 281 vm_page_t m; 282 283 m = sf_buf_page(sf); 284 sf_buf_free(sf); 285 sched_unpin(); 286 vm_page_lock(m); 287 vm_page_unhold(m); 288 vm_page_unlock(m); 289 } 290 291 void 292 vm_sync_icache(vm_map_t map, vm_offset_t va, vm_offset_t sz) 293 { 294 295 pmap_sync_icache(map->pmap, va, sz); 296 } 297 298 struct kstack_cache_entry *kstack_cache; 299 static int kstack_cache_size = 128; 300 static int kstacks; 301 static struct mtx kstack_cache_mtx; 302 MTX_SYSINIT(kstack_cache, &kstack_cache_mtx, "kstkch", MTX_DEF); 303 304 SYSCTL_INT(_vm, OID_AUTO, kstack_cache_size, CTLFLAG_RW, &kstack_cache_size, 0, 305 ""); 306 SYSCTL_INT(_vm, OID_AUTO, kstacks, CTLFLAG_RD, &kstacks, 0, 307 ""); 308 309 /* 310 * Create the kernel stack (including pcb for i386) for a new thread. 311 * This routine directly affects the fork perf for a process and 312 * create performance for a thread. 313 */ 314 int 315 vm_thread_new(struct thread *td, int pages) 316 { 317 vm_object_t ksobj; 318 vm_offset_t ks; 319 vm_page_t ma[KSTACK_MAX_PAGES]; 320 struct kstack_cache_entry *ks_ce; 321 int i; 322 323 /* Bounds check */ 324 if (pages <= 1) 325 pages = kstack_pages; 326 else if (pages > KSTACK_MAX_PAGES) 327 pages = KSTACK_MAX_PAGES; 328 329 if (pages == kstack_pages) { 330 mtx_lock(&kstack_cache_mtx); 331 if (kstack_cache != NULL) { 332 ks_ce = kstack_cache; 333 kstack_cache = ks_ce->next_ks_entry; 334 mtx_unlock(&kstack_cache_mtx); 335 336 td->td_kstack_obj = ks_ce->ksobj; 337 td->td_kstack = (vm_offset_t)ks_ce; 338 td->td_kstack_pages = kstack_pages; 339 return (1); 340 } 341 mtx_unlock(&kstack_cache_mtx); 342 } 343 344 /* 345 * Allocate an object for the kstack. 346 */ 347 ksobj = vm_object_allocate(OBJT_DEFAULT, pages); 348 349 /* 350 * Get a kernel virtual address for this thread's kstack. 351 */ 352 #if defined(__mips__) 353 /* 354 * We need to align the kstack's mapped address to fit within 355 * a single TLB entry. 356 */ 357 if (vmem_xalloc(kernel_arena, (pages + KSTACK_GUARD_PAGES) * PAGE_SIZE, 358 PAGE_SIZE * 2, 0, 0, VMEM_ADDR_MIN, VMEM_ADDR_MAX, 359 M_BESTFIT | M_NOWAIT, &ks)) { 360 ks = 0; 361 } 362 #else 363 ks = kva_alloc((pages + KSTACK_GUARD_PAGES) * PAGE_SIZE); 364 #endif 365 if (ks == 0) { 366 printf("vm_thread_new: kstack allocation failed\n"); 367 vm_object_deallocate(ksobj); 368 return (0); 369 } 370 371 atomic_add_int(&kstacks, 1); 372 if (KSTACK_GUARD_PAGES != 0) { 373 pmap_qremove(ks, KSTACK_GUARD_PAGES); 374 ks += KSTACK_GUARD_PAGES * PAGE_SIZE; 375 } 376 td->td_kstack_obj = ksobj; 377 td->td_kstack = ks; 378 /* 379 * Knowing the number of pages allocated is useful when you 380 * want to deallocate them. 381 */ 382 td->td_kstack_pages = pages; 383 /* 384 * For the length of the stack, link in a real page of ram for each 385 * page of stack. 386 */ 387 VM_OBJECT_WLOCK(ksobj); 388 (void)vm_page_grab_pages(ksobj, 0, VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY | 389 VM_ALLOC_WIRED, ma, pages); 390 for (i = 0; i < pages; i++) 391 ma[i]->valid = VM_PAGE_BITS_ALL; 392 VM_OBJECT_WUNLOCK(ksobj); 393 pmap_qenter(ks, ma, pages); 394 return (1); 395 } 396 397 static void 398 vm_thread_stack_dispose(vm_object_t ksobj, vm_offset_t ks, int pages) 399 { 400 vm_page_t m; 401 int i; 402 403 atomic_add_int(&kstacks, -1); 404 pmap_qremove(ks, pages); 405 VM_OBJECT_WLOCK(ksobj); 406 for (i = 0; i < pages; i++) { 407 m = vm_page_lookup(ksobj, i); 408 if (m == NULL) 409 panic("vm_thread_dispose: kstack already missing?"); 410 vm_page_lock(m); 411 vm_page_unwire(m, PQ_NONE); 412 vm_page_free(m); 413 vm_page_unlock(m); 414 } 415 VM_OBJECT_WUNLOCK(ksobj); 416 vm_object_deallocate(ksobj); 417 kva_free(ks - (KSTACK_GUARD_PAGES * PAGE_SIZE), 418 (pages + KSTACK_GUARD_PAGES) * PAGE_SIZE); 419 } 420 421 /* 422 * Dispose of a thread's kernel stack. 423 */ 424 void 425 vm_thread_dispose(struct thread *td) 426 { 427 vm_object_t ksobj; 428 vm_offset_t ks; 429 struct kstack_cache_entry *ks_ce; 430 int pages; 431 432 pages = td->td_kstack_pages; 433 ksobj = td->td_kstack_obj; 434 ks = td->td_kstack; 435 td->td_kstack = 0; 436 td->td_kstack_pages = 0; 437 if (pages == kstack_pages && kstacks <= kstack_cache_size) { 438 ks_ce = (struct kstack_cache_entry *)ks; 439 ks_ce->ksobj = ksobj; 440 mtx_lock(&kstack_cache_mtx); 441 ks_ce->next_ks_entry = kstack_cache; 442 kstack_cache = ks_ce; 443 mtx_unlock(&kstack_cache_mtx); 444 return; 445 } 446 vm_thread_stack_dispose(ksobj, ks, pages); 447 } 448 449 static void 450 vm_thread_stack_lowmem(void *nulll) 451 { 452 struct kstack_cache_entry *ks_ce, *ks_ce1; 453 454 mtx_lock(&kstack_cache_mtx); 455 ks_ce = kstack_cache; 456 kstack_cache = NULL; 457 mtx_unlock(&kstack_cache_mtx); 458 459 while (ks_ce != NULL) { 460 ks_ce1 = ks_ce; 461 ks_ce = ks_ce->next_ks_entry; 462 463 vm_thread_stack_dispose(ks_ce1->ksobj, (vm_offset_t)ks_ce1, 464 kstack_pages); 465 } 466 } 467 468 static void 469 kstack_cache_init(void *nulll) 470 { 471 472 EVENTHANDLER_REGISTER(vm_lowmem, vm_thread_stack_lowmem, NULL, 473 EVENTHANDLER_PRI_ANY); 474 } 475 476 SYSINIT(vm_kstacks, SI_SUB_KTHREAD_INIT, SI_ORDER_ANY, kstack_cache_init, NULL); 477 478 #ifdef KSTACK_USAGE_PROF 479 /* 480 * Track maximum stack used by a thread in kernel. 481 */ 482 static int max_kstack_used; 483 484 SYSCTL_INT(_debug, OID_AUTO, max_kstack_used, CTLFLAG_RD, 485 &max_kstack_used, 0, 486 "Maxiumum stack depth used by a thread in kernel"); 487 488 void 489 intr_prof_stack_use(struct thread *td, struct trapframe *frame) 490 { 491 vm_offset_t stack_top; 492 vm_offset_t current; 493 int used, prev_used; 494 495 /* 496 * Testing for interrupted kernel mode isn't strictly 497 * needed. It optimizes the execution, since interrupts from 498 * usermode will have only the trap frame on the stack. 499 */ 500 if (TRAPF_USERMODE(frame)) 501 return; 502 503 stack_top = td->td_kstack + td->td_kstack_pages * PAGE_SIZE; 504 current = (vm_offset_t)(uintptr_t)&stack_top; 505 506 /* 507 * Try to detect if interrupt is using kernel thread stack. 508 * Hardware could use a dedicated stack for interrupt handling. 509 */ 510 if (stack_top <= current || current < td->td_kstack) 511 return; 512 513 used = stack_top - current; 514 for (;;) { 515 prev_used = max_kstack_used; 516 if (prev_used >= used) 517 break; 518 if (atomic_cmpset_int(&max_kstack_used, prev_used, used)) 519 break; 520 } 521 } 522 #endif /* KSTACK_USAGE_PROF */ 523 524 /* 525 * Implement fork's actions on an address space. 526 * Here we arrange for the address space to be copied or referenced, 527 * allocate a user struct (pcb and kernel stack), then call the 528 * machine-dependent layer to fill those in and make the new process 529 * ready to run. The new process is set up so that it returns directly 530 * to user mode to avoid stack copying and relocation problems. 531 */ 532 int 533 vm_forkproc(struct thread *td, struct proc *p2, struct thread *td2, 534 struct vmspace *vm2, int flags) 535 { 536 struct proc *p1 = td->td_proc; 537 int error; 538 539 if ((flags & RFPROC) == 0) { 540 /* 541 * Divorce the memory, if it is shared, essentially 542 * this changes shared memory amongst threads, into 543 * COW locally. 544 */ 545 if ((flags & RFMEM) == 0) { 546 if (p1->p_vmspace->vm_refcnt > 1) { 547 error = vmspace_unshare(p1); 548 if (error) 549 return (error); 550 } 551 } 552 cpu_fork(td, p2, td2, flags); 553 return (0); 554 } 555 556 if (flags & RFMEM) { 557 p2->p_vmspace = p1->p_vmspace; 558 atomic_add_int(&p1->p_vmspace->vm_refcnt, 1); 559 } 560 561 while (vm_page_count_severe()) { 562 vm_wait_severe(); 563 } 564 565 if ((flags & RFMEM) == 0) { 566 p2->p_vmspace = vm2; 567 if (p1->p_vmspace->vm_shm) 568 shmfork(p1, p2); 569 } 570 571 /* 572 * cpu_fork will copy and update the pcb, set up the kernel stack, 573 * and make the child ready to run. 574 */ 575 cpu_fork(td, p2, td2, flags); 576 return (0); 577 } 578 579 /* 580 * Called after process has been wait(2)'ed upon and is being reaped. 581 * The idea is to reclaim resources that we could not reclaim while 582 * the process was still executing. 583 */ 584 void 585 vm_waitproc(p) 586 struct proc *p; 587 { 588 589 vmspace_exitfree(p); /* and clean-out the vmspace */ 590 } 591 592 void 593 kick_proc0(void) 594 { 595 596 wakeup(&proc0); 597 } 598