1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 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(addr, len, rw) 117 void *addr; 118 int len, rw; 119 { 120 boolean_t rv; 121 vm_offset_t saddr, eaddr; 122 vm_prot_t prot; 123 124 KASSERT((rw & ~VM_PROT_ALL) == 0, 125 ("illegal ``rw'' argument to kernacc (%x)\n", rw)); 126 127 if ((vm_offset_t)addr + len > kernel_map->max_offset || 128 (vm_offset_t)addr + len < (vm_offset_t)addr) 129 return (FALSE); 130 131 prot = rw; 132 saddr = trunc_page((vm_offset_t)addr); 133 eaddr = round_page((vm_offset_t)addr + len); 134 vm_map_lock_read(kernel_map); 135 rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot); 136 vm_map_unlock_read(kernel_map); 137 return (rv == TRUE); 138 } 139 140 /* 141 * MPSAFE 142 * 143 * WARNING! This code calls vm_map_check_protection() which only checks 144 * the associated vm_map_entry range. It does not determine whether the 145 * contents of the memory is actually readable or writable. vmapbuf(), 146 * vm_fault_quick(), or copyin()/copout()/su*()/fu*() functions should be 147 * used in conjunction with this call. 148 */ 149 int 150 useracc(addr, len, rw) 151 void *addr; 152 int len, rw; 153 { 154 boolean_t rv; 155 vm_prot_t prot; 156 vm_map_t map; 157 158 KASSERT((rw & ~VM_PROT_ALL) == 0, 159 ("illegal ``rw'' argument to useracc (%x)\n", rw)); 160 prot = rw; 161 map = &curproc->p_vmspace->vm_map; 162 if ((vm_offset_t)addr + len > vm_map_max(map) || 163 (vm_offset_t)addr + len < (vm_offset_t)addr) { 164 return (FALSE); 165 } 166 vm_map_lock_read(map); 167 rv = vm_map_check_protection(map, trunc_page((vm_offset_t)addr), 168 round_page((vm_offset_t)addr + len), prot); 169 vm_map_unlock_read(map); 170 return (rv == TRUE); 171 } 172 173 int 174 vslock(void *addr, size_t len) 175 { 176 vm_offset_t end, last, start; 177 vm_size_t npages; 178 int error; 179 180 last = (vm_offset_t)addr + len; 181 start = trunc_page((vm_offset_t)addr); 182 end = round_page(last); 183 if (last < (vm_offset_t)addr || end < (vm_offset_t)addr) 184 return (EINVAL); 185 npages = atop(end - start); 186 if (npages > vm_page_max_wired) 187 return (ENOMEM); 188 #if 0 189 /* 190 * XXX - not yet 191 * 192 * The limit for transient usage of wired pages should be 193 * larger than for "permanent" wired pages (mlock()). 194 * 195 * Also, the sysctl code, which is the only present user 196 * of vslock(), does a hard loop on EAGAIN. 197 */ 198 if (npages + vm_cnt.v_wire_count > vm_page_max_wired) 199 return (EAGAIN); 200 #endif 201 error = vm_map_wire(&curproc->p_vmspace->vm_map, start, end, 202 VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES); 203 /* 204 * Return EFAULT on error to match copy{in,out}() behaviour 205 * rather than returning ENOMEM like mlock() would. 206 */ 207 return (error == KERN_SUCCESS ? 0 : EFAULT); 208 } 209 210 void 211 vsunlock(void *addr, size_t len) 212 { 213 214 /* Rely on the parameter sanity checks performed by vslock(). */ 215 (void)vm_map_unwire(&curproc->p_vmspace->vm_map, 216 trunc_page((vm_offset_t)addr), round_page((vm_offset_t)addr + len), 217 VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES); 218 } 219 220 /* 221 * Pin the page contained within the given object at the given offset. If the 222 * page is not resident, allocate and load it using the given object's pager. 223 * Return the pinned page if successful; otherwise, return NULL. 224 */ 225 static vm_page_t 226 vm_imgact_hold_page(vm_object_t object, vm_ooffset_t offset) 227 { 228 vm_page_t m; 229 vm_pindex_t pindex; 230 int rv; 231 232 VM_OBJECT_WLOCK(object); 233 pindex = OFF_TO_IDX(offset); 234 m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY); 235 if (m->valid != VM_PAGE_BITS_ALL) { 236 vm_page_xbusy(m); 237 rv = vm_pager_get_pages(object, &m, 1, NULL, NULL); 238 if (rv != VM_PAGER_OK) { 239 vm_page_lock(m); 240 vm_page_free(m); 241 vm_page_unlock(m); 242 m = NULL; 243 goto out; 244 } 245 vm_page_xunbusy(m); 246 } 247 vm_page_lock(m); 248 vm_page_hold(m); 249 vm_page_activate(m); 250 vm_page_unlock(m); 251 out: 252 VM_OBJECT_WUNLOCK(object); 253 return (m); 254 } 255 256 /* 257 * Return a CPU private mapping to the page at the given offset within the 258 * given object. The page is pinned before it is mapped. 259 */ 260 struct sf_buf * 261 vm_imgact_map_page(vm_object_t object, vm_ooffset_t offset) 262 { 263 vm_page_t m; 264 265 m = vm_imgact_hold_page(object, offset); 266 if (m == NULL) 267 return (NULL); 268 sched_pin(); 269 return (sf_buf_alloc(m, SFB_CPUPRIVATE)); 270 } 271 272 /* 273 * Destroy the given CPU private mapping and unpin the page that it mapped. 274 */ 275 void 276 vm_imgact_unmap_page(struct sf_buf *sf) 277 { 278 vm_page_t m; 279 280 m = sf_buf_page(sf); 281 sf_buf_free(sf); 282 sched_unpin(); 283 vm_page_lock(m); 284 vm_page_unhold(m); 285 vm_page_unlock(m); 286 } 287 288 void 289 vm_sync_icache(vm_map_t map, vm_offset_t va, vm_offset_t sz) 290 { 291 292 pmap_sync_icache(map->pmap, va, sz); 293 } 294 295 struct kstack_cache_entry *kstack_cache; 296 static int kstack_cache_size = 128; 297 static int kstacks; 298 static struct mtx kstack_cache_mtx; 299 MTX_SYSINIT(kstack_cache, &kstack_cache_mtx, "kstkch", MTX_DEF); 300 301 SYSCTL_INT(_vm, OID_AUTO, kstack_cache_size, CTLFLAG_RW, &kstack_cache_size, 0, 302 ""); 303 SYSCTL_INT(_vm, OID_AUTO, kstacks, CTLFLAG_RD, &kstacks, 0, 304 ""); 305 306 /* 307 * Create the kernel stack (including pcb for i386) for a new thread. 308 * This routine directly affects the fork perf for a process and 309 * create performance for a thread. 310 */ 311 int 312 vm_thread_new(struct thread *td, int pages) 313 { 314 vm_object_t ksobj; 315 vm_offset_t ks; 316 vm_page_t ma[KSTACK_MAX_PAGES]; 317 struct kstack_cache_entry *ks_ce; 318 int i; 319 320 /* Bounds check */ 321 if (pages <= 1) 322 pages = kstack_pages; 323 else if (pages > KSTACK_MAX_PAGES) 324 pages = KSTACK_MAX_PAGES; 325 326 if (pages == kstack_pages) { 327 mtx_lock(&kstack_cache_mtx); 328 if (kstack_cache != NULL) { 329 ks_ce = kstack_cache; 330 kstack_cache = ks_ce->next_ks_entry; 331 mtx_unlock(&kstack_cache_mtx); 332 333 td->td_kstack_obj = ks_ce->ksobj; 334 td->td_kstack = (vm_offset_t)ks_ce; 335 td->td_kstack_pages = kstack_pages; 336 return (1); 337 } 338 mtx_unlock(&kstack_cache_mtx); 339 } 340 341 /* 342 * Allocate an object for the kstack. 343 */ 344 ksobj = vm_object_allocate(OBJT_DEFAULT, pages); 345 346 /* 347 * Get a kernel virtual address for this thread's kstack. 348 */ 349 #if defined(__mips__) 350 /* 351 * We need to align the kstack's mapped address to fit within 352 * a single TLB entry. 353 */ 354 if (vmem_xalloc(kernel_arena, (pages + KSTACK_GUARD_PAGES) * PAGE_SIZE, 355 PAGE_SIZE * 2, 0, 0, VMEM_ADDR_MIN, VMEM_ADDR_MAX, 356 M_BESTFIT | M_NOWAIT, &ks)) { 357 ks = 0; 358 } 359 #else 360 ks = kva_alloc((pages + KSTACK_GUARD_PAGES) * PAGE_SIZE); 361 #endif 362 if (ks == 0) { 363 printf("vm_thread_new: kstack allocation failed\n"); 364 vm_object_deallocate(ksobj); 365 return (0); 366 } 367 368 atomic_add_int(&kstacks, 1); 369 if (KSTACK_GUARD_PAGES != 0) { 370 pmap_qremove(ks, KSTACK_GUARD_PAGES); 371 ks += KSTACK_GUARD_PAGES * PAGE_SIZE; 372 } 373 td->td_kstack_obj = ksobj; 374 td->td_kstack = ks; 375 /* 376 * Knowing the number of pages allocated is useful when you 377 * want to deallocate them. 378 */ 379 td->td_kstack_pages = pages; 380 /* 381 * For the length of the stack, link in a real page of ram for each 382 * page of stack. 383 */ 384 VM_OBJECT_WLOCK(ksobj); 385 (void)vm_page_grab_pages(ksobj, 0, VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY | 386 VM_ALLOC_WIRED, ma, pages); 387 for (i = 0; i < pages; i++) 388 ma[i]->valid = VM_PAGE_BITS_ALL; 389 VM_OBJECT_WUNLOCK(ksobj); 390 pmap_qenter(ks, ma, pages); 391 return (1); 392 } 393 394 static void 395 vm_thread_stack_dispose(vm_object_t ksobj, vm_offset_t ks, int pages) 396 { 397 vm_page_t m; 398 int i; 399 400 atomic_add_int(&kstacks, -1); 401 pmap_qremove(ks, pages); 402 VM_OBJECT_WLOCK(ksobj); 403 for (i = 0; i < pages; i++) { 404 m = vm_page_lookup(ksobj, i); 405 if (m == NULL) 406 panic("vm_thread_dispose: kstack already missing?"); 407 vm_page_lock(m); 408 vm_page_unwire(m, PQ_NONE); 409 vm_page_free(m); 410 vm_page_unlock(m); 411 } 412 VM_OBJECT_WUNLOCK(ksobj); 413 vm_object_deallocate(ksobj); 414 kva_free(ks - (KSTACK_GUARD_PAGES * PAGE_SIZE), 415 (pages + KSTACK_GUARD_PAGES) * PAGE_SIZE); 416 } 417 418 /* 419 * Dispose of a thread's kernel stack. 420 */ 421 void 422 vm_thread_dispose(struct thread *td) 423 { 424 vm_object_t ksobj; 425 vm_offset_t ks; 426 struct kstack_cache_entry *ks_ce; 427 int pages; 428 429 pages = td->td_kstack_pages; 430 ksobj = td->td_kstack_obj; 431 ks = td->td_kstack; 432 td->td_kstack = 0; 433 td->td_kstack_pages = 0; 434 if (pages == kstack_pages && kstacks <= kstack_cache_size) { 435 ks_ce = (struct kstack_cache_entry *)ks; 436 ks_ce->ksobj = ksobj; 437 mtx_lock(&kstack_cache_mtx); 438 ks_ce->next_ks_entry = kstack_cache; 439 kstack_cache = ks_ce; 440 mtx_unlock(&kstack_cache_mtx); 441 return; 442 } 443 vm_thread_stack_dispose(ksobj, ks, pages); 444 } 445 446 static void 447 vm_thread_stack_lowmem(void *nulll) 448 { 449 struct kstack_cache_entry *ks_ce, *ks_ce1; 450 451 mtx_lock(&kstack_cache_mtx); 452 ks_ce = kstack_cache; 453 kstack_cache = NULL; 454 mtx_unlock(&kstack_cache_mtx); 455 456 while (ks_ce != NULL) { 457 ks_ce1 = ks_ce; 458 ks_ce = ks_ce->next_ks_entry; 459 460 vm_thread_stack_dispose(ks_ce1->ksobj, (vm_offset_t)ks_ce1, 461 kstack_pages); 462 } 463 } 464 465 static void 466 kstack_cache_init(void *nulll) 467 { 468 469 EVENTHANDLER_REGISTER(vm_lowmem, vm_thread_stack_lowmem, NULL, 470 EVENTHANDLER_PRI_ANY); 471 } 472 473 SYSINIT(vm_kstacks, SI_SUB_KTHREAD_INIT, SI_ORDER_ANY, kstack_cache_init, NULL); 474 475 #ifdef KSTACK_USAGE_PROF 476 /* 477 * Track maximum stack used by a thread in kernel. 478 */ 479 static int max_kstack_used; 480 481 SYSCTL_INT(_debug, OID_AUTO, max_kstack_used, CTLFLAG_RD, 482 &max_kstack_used, 0, 483 "Maxiumum stack depth used by a thread in kernel"); 484 485 void 486 intr_prof_stack_use(struct thread *td, struct trapframe *frame) 487 { 488 vm_offset_t stack_top; 489 vm_offset_t current; 490 int used, prev_used; 491 492 /* 493 * Testing for interrupted kernel mode isn't strictly 494 * needed. It optimizes the execution, since interrupts from 495 * usermode will have only the trap frame on the stack. 496 */ 497 if (TRAPF_USERMODE(frame)) 498 return; 499 500 stack_top = td->td_kstack + td->td_kstack_pages * PAGE_SIZE; 501 current = (vm_offset_t)(uintptr_t)&stack_top; 502 503 /* 504 * Try to detect if interrupt is using kernel thread stack. 505 * Hardware could use a dedicated stack for interrupt handling. 506 */ 507 if (stack_top <= current || current < td->td_kstack) 508 return; 509 510 used = stack_top - current; 511 for (;;) { 512 prev_used = max_kstack_used; 513 if (prev_used >= used) 514 break; 515 if (atomic_cmpset_int(&max_kstack_used, prev_used, used)) 516 break; 517 } 518 } 519 #endif /* KSTACK_USAGE_PROF */ 520 521 /* 522 * Implement fork's actions on an address space. 523 * Here we arrange for the address space to be copied or referenced, 524 * allocate a user struct (pcb and kernel stack), then call the 525 * machine-dependent layer to fill those in and make the new process 526 * ready to run. The new process is set up so that it returns directly 527 * to user mode to avoid stack copying and relocation problems. 528 */ 529 int 530 vm_forkproc(td, p2, td2, vm2, flags) 531 struct thread *td; 532 struct proc *p2; 533 struct thread *td2; 534 struct vmspace *vm2; 535 int flags; 536 { 537 struct proc *p1 = td->td_proc; 538 int error; 539 540 if ((flags & RFPROC) == 0) { 541 /* 542 * Divorce the memory, if it is shared, essentially 543 * this changes shared memory amongst threads, into 544 * COW locally. 545 */ 546 if ((flags & RFMEM) == 0) { 547 if (p1->p_vmspace->vm_refcnt > 1) { 548 error = vmspace_unshare(p1); 549 if (error) 550 return (error); 551 } 552 } 553 cpu_fork(td, p2, td2, flags); 554 return (0); 555 } 556 557 if (flags & RFMEM) { 558 p2->p_vmspace = p1->p_vmspace; 559 atomic_add_int(&p1->p_vmspace->vm_refcnt, 1); 560 } 561 562 while (vm_page_count_severe()) { 563 VM_WAIT; 564 } 565 566 if ((flags & RFMEM) == 0) { 567 p2->p_vmspace = vm2; 568 if (p1->p_vmspace->vm_shm) 569 shmfork(p1, p2); 570 } 571 572 /* 573 * cpu_fork will copy and update the pcb, set up the kernel stack, 574 * and make the child ready to run. 575 */ 576 cpu_fork(td, p2, td2, flags); 577 return (0); 578 } 579 580 /* 581 * Called after process has been wait(2)'ed upon and is being reaped. 582 * The idea is to reclaim resources that we could not reclaim while 583 * the process was still executing. 584 */ 585 void 586 vm_waitproc(p) 587 struct proc *p; 588 { 589 590 vmspace_exitfree(p); /* and clean-out the vmspace */ 591 } 592 593 void 594 kick_proc0(void) 595 { 596 597 wakeup(&proc0); 598 } 599