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 #include "opt_vm.h"
63 #include "opt_kstack_pages.h"
64 #include "opt_kstack_max_pages.h"
65 #include "opt_kstack_usage_prof.h"
66
67 #include <sys/param.h>
68 #include <sys/systm.h>
69 #include <sys/asan.h>
70 #include <sys/domainset.h>
71 #include <sys/limits.h>
72 #include <sys/lock.h>
73 #include <sys/malloc.h>
74 #include <sys/msan.h>
75 #include <sys/mutex.h>
76 #include <sys/proc.h>
77 #include <sys/racct.h>
78 #include <sys/refcount.h>
79 #include <sys/resourcevar.h>
80 #include <sys/rwlock.h>
81 #include <sys/sched.h>
82 #include <sys/sf_buf.h>
83 #include <sys/shm.h>
84 #include <sys/smp.h>
85 #include <sys/vmmeter.h>
86 #include <sys/vmem.h>
87 #include <sys/sx.h>
88 #include <sys/sysctl.h>
89 #include <sys/kernel.h>
90 #include <sys/ktr.h>
91 #include <sys/unistd.h>
92
93 #include <vm/uma.h>
94 #include <vm/vm.h>
95 #include <vm/vm_param.h>
96 #include <vm/pmap.h>
97 #include <vm/vm_domainset.h>
98 #include <vm/vm_map.h>
99 #include <vm/vm_page.h>
100 #include <vm/vm_pageout.h>
101 #include <vm/vm_object.h>
102 #include <vm/vm_kern.h>
103 #include <vm/vm_extern.h>
104 #include <vm/vm_pager.h>
105 #include <vm/swap_pager.h>
106
107 #include <machine/cpu.h>
108
109 /*
110 * MPSAFE
111 *
112 * WARNING! This code calls vm_map_check_protection() which only checks
113 * the associated vm_map_entry range. It does not determine whether the
114 * contents of the memory is actually readable or writable. In most cases
115 * just checking the vm_map_entry is sufficient within the kernel's address
116 * space.
117 */
118 int
kernacc(void * addr,int len,int rw)119 kernacc(void *addr, int len, int rw)
120 {
121 boolean_t rv;
122 vm_offset_t saddr, eaddr;
123 vm_prot_t prot;
124
125 KASSERT((rw & ~VM_PROT_ALL) == 0,
126 ("illegal ``rw'' argument to kernacc (%x)\n", rw));
127
128 if ((vm_offset_t)addr + len > vm_map_max(kernel_map) ||
129 (vm_offset_t)addr + len < (vm_offset_t)addr)
130 return (FALSE);
131
132 prot = rw;
133 saddr = trunc_page((vm_offset_t)addr);
134 eaddr = round_page((vm_offset_t)addr + len);
135 vm_map_lock_read(kernel_map);
136 rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot);
137 vm_map_unlock_read(kernel_map);
138 return (rv == TRUE);
139 }
140
141 /*
142 * MPSAFE
143 *
144 * WARNING! This code calls vm_map_check_protection() which only checks
145 * the associated vm_map_entry range. It does not determine whether the
146 * contents of the memory is actually readable or writable. vmapbuf(),
147 * vm_fault_quick(), or copyin()/copout()/su*()/fu*() functions should be
148 * used in conjunction with this call.
149 */
150 int
useracc(void * addr,int len,int rw)151 useracc(void *addr, int len, int rw)
152 {
153 boolean_t rv;
154 vm_prot_t prot;
155 vm_map_t map;
156
157 KASSERT((rw & ~VM_PROT_ALL) == 0,
158 ("illegal ``rw'' argument to useracc (%x)\n", rw));
159 prot = rw;
160 map = &curproc->p_vmspace->vm_map;
161 if ((vm_offset_t)addr + len > vm_map_max(map) ||
162 (vm_offset_t)addr + len < (vm_offset_t)addr) {
163 return (FALSE);
164 }
165 vm_map_lock_read(map);
166 rv = vm_map_check_protection(map, trunc_page((vm_offset_t)addr),
167 round_page((vm_offset_t)addr + len), prot);
168 vm_map_unlock_read(map);
169 return (rv == TRUE);
170 }
171
172 int
vslock(void * addr,size_t len)173 vslock(void *addr, size_t len)
174 {
175 vm_offset_t end, last, start;
176 vm_size_t npages;
177 int error;
178
179 last = (vm_offset_t)addr + len;
180 start = trunc_page((vm_offset_t)addr);
181 end = round_page(last);
182 if (last < (vm_offset_t)addr || end < (vm_offset_t)addr)
183 return (EINVAL);
184 npages = atop(end - start);
185 if (npages > vm_page_max_user_wired)
186 return (ENOMEM);
187 error = vm_map_wire(&curproc->p_vmspace->vm_map, start, end,
188 VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES);
189 if (error == KERN_SUCCESS) {
190 curthread->td_vslock_sz += len;
191 return (0);
192 }
193
194 /*
195 * Return EFAULT on error to match copy{in,out}() behaviour
196 * rather than returning ENOMEM like mlock() would.
197 */
198 return (EFAULT);
199 }
200
201 void
vsunlock(void * addr,size_t len)202 vsunlock(void *addr, size_t len)
203 {
204
205 /* Rely on the parameter sanity checks performed by vslock(). */
206 MPASS(curthread->td_vslock_sz >= len);
207 curthread->td_vslock_sz -= len;
208 (void)vm_map_unwire(&curproc->p_vmspace->vm_map,
209 trunc_page((vm_offset_t)addr), round_page((vm_offset_t)addr + len),
210 VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES);
211 }
212
213 /*
214 * Pin the page contained within the given object at the given offset. If the
215 * page is not resident, allocate and load it using the given object's pager.
216 * Return the pinned page if successful; otherwise, return NULL.
217 */
218 static vm_page_t
vm_imgact_hold_page(vm_object_t object,vm_ooffset_t offset)219 vm_imgact_hold_page(vm_object_t object, vm_ooffset_t offset)
220 {
221 vm_page_t m;
222 vm_pindex_t pindex;
223
224 pindex = OFF_TO_IDX(offset);
225 (void)vm_page_grab_valid_unlocked(&m, object, pindex,
226 VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED);
227 return (m);
228 }
229
230 /*
231 * Return a CPU private mapping to the page at the given offset within the
232 * given object. The page is pinned before it is mapped.
233 */
234 struct sf_buf *
vm_imgact_map_page(vm_object_t object,vm_ooffset_t offset)235 vm_imgact_map_page(vm_object_t object, vm_ooffset_t offset)
236 {
237 vm_page_t m;
238
239 m = vm_imgact_hold_page(object, offset);
240 if (m == NULL)
241 return (NULL);
242 sched_pin();
243 return (sf_buf_alloc(m, SFB_CPUPRIVATE));
244 }
245
246 /*
247 * Destroy the given CPU private mapping and unpin the page that it mapped.
248 */
249 void
vm_imgact_unmap_page(struct sf_buf * sf)250 vm_imgact_unmap_page(struct sf_buf *sf)
251 {
252 vm_page_t m;
253
254 m = sf_buf_page(sf);
255 sf_buf_free(sf);
256 sched_unpin();
257 vm_page_unwire(m, PQ_ACTIVE);
258 }
259
260 void
vm_sync_icache(vm_map_t map,vm_offset_t va,vm_offset_t sz)261 vm_sync_icache(vm_map_t map, vm_offset_t va, vm_offset_t sz)
262 {
263
264 pmap_sync_icache(map->pmap, va, sz);
265 }
266
267 vm_object_t kstack_object;
268 static uma_zone_t kstack_cache;
269 static int kstack_cache_size;
270
271 static int
sysctl_kstack_cache_size(SYSCTL_HANDLER_ARGS)272 sysctl_kstack_cache_size(SYSCTL_HANDLER_ARGS)
273 {
274 int error, oldsize;
275
276 oldsize = kstack_cache_size;
277 error = sysctl_handle_int(oidp, arg1, arg2, req);
278 if (error == 0 && req->newptr && oldsize != kstack_cache_size)
279 uma_zone_set_maxcache(kstack_cache, kstack_cache_size);
280 return (error);
281 }
282 SYSCTL_PROC(_vm, OID_AUTO, kstack_cache_size,
283 CTLTYPE_INT|CTLFLAG_MPSAFE|CTLFLAG_RW, &kstack_cache_size, 0,
284 sysctl_kstack_cache_size, "IU", "Maximum number of cached kernel stacks");
285
286 /*
287 * Create the kernel stack (including pcb for i386) for a new thread.
288 */
289 static vm_offset_t
vm_thread_stack_create(struct domainset * ds,int pages)290 vm_thread_stack_create(struct domainset *ds, int pages)
291 {
292 vm_page_t ma[KSTACK_MAX_PAGES];
293 vm_offset_t ks;
294 int i;
295
296 /*
297 * Get a kernel virtual address for this thread's kstack.
298 */
299 ks = kva_alloc((pages + KSTACK_GUARD_PAGES) * PAGE_SIZE);
300 if (ks == 0) {
301 printf("%s: kstack allocation failed\n", __func__);
302 return (0);
303 }
304
305 if (KSTACK_GUARD_PAGES != 0) {
306 pmap_qremove(ks, KSTACK_GUARD_PAGES);
307 ks += KSTACK_GUARD_PAGES * PAGE_SIZE;
308 }
309
310 /*
311 * Allocate physical pages to back the stack.
312 */
313 vm_thread_stack_back(ds, ks, ma, pages, VM_ALLOC_NORMAL);
314 for (i = 0; i < pages; i++)
315 vm_page_valid(ma[i]);
316 pmap_qenter(ks, ma, pages);
317
318 return (ks);
319 }
320
321 static void
vm_thread_stack_dispose(vm_offset_t ks,int pages)322 vm_thread_stack_dispose(vm_offset_t ks, int pages)
323 {
324 vm_page_t m;
325 vm_pindex_t pindex;
326 int i;
327
328 pindex = atop(ks - VM_MIN_KERNEL_ADDRESS);
329
330 pmap_qremove(ks, pages);
331 VM_OBJECT_WLOCK(kstack_object);
332 for (i = 0; i < pages; i++) {
333 m = vm_page_lookup(kstack_object, pindex + i);
334 if (m == NULL)
335 panic("%s: kstack already missing?", __func__);
336 vm_page_xbusy_claim(m);
337 vm_page_unwire_noq(m);
338 vm_page_free(m);
339 }
340 VM_OBJECT_WUNLOCK(kstack_object);
341 kasan_mark((void *)ks, ptoa(pages), ptoa(pages), 0);
342 kva_free(ks - (KSTACK_GUARD_PAGES * PAGE_SIZE),
343 (pages + KSTACK_GUARD_PAGES) * PAGE_SIZE);
344 }
345
346 /*
347 * Allocate the kernel stack for a new thread.
348 */
349 int
vm_thread_new(struct thread * td,int pages)350 vm_thread_new(struct thread *td, int pages)
351 {
352 vm_offset_t ks;
353
354 /* Bounds check */
355 if (pages <= 1)
356 pages = kstack_pages;
357 else if (pages > KSTACK_MAX_PAGES)
358 pages = KSTACK_MAX_PAGES;
359
360 ks = 0;
361 if (pages == kstack_pages && kstack_cache != NULL)
362 ks = (vm_offset_t)uma_zalloc(kstack_cache, M_NOWAIT);
363
364 /*
365 * Ensure that kstack objects can draw pages from any memory
366 * domain. Otherwise a local memory shortage can block a process
367 * swap-in.
368 */
369 if (ks == 0)
370 ks = vm_thread_stack_create(DOMAINSET_PREF(PCPU_GET(domain)),
371 pages);
372 if (ks == 0)
373 return (0);
374 td->td_kstack = ks;
375 td->td_kstack_pages = pages;
376 kasan_mark((void *)ks, ptoa(pages), ptoa(pages), 0);
377 kmsan_mark((void *)ks, ptoa(pages), KMSAN_STATE_UNINIT);
378 return (1);
379 }
380
381 /*
382 * Dispose of a thread's kernel stack.
383 */
384 void
vm_thread_dispose(struct thread * td)385 vm_thread_dispose(struct thread *td)
386 {
387 vm_offset_t ks;
388 int pages;
389
390 pages = td->td_kstack_pages;
391 ks = td->td_kstack;
392 td->td_kstack = 0;
393 td->td_kstack_pages = 0;
394 if (pages == kstack_pages) {
395 kasan_mark((void *)ks, 0, ptoa(pages), KASAN_KSTACK_FREED);
396 uma_zfree(kstack_cache, (void *)ks);
397 } else {
398 vm_thread_stack_dispose(ks, pages);
399 }
400 }
401
402 /*
403 * Allocate physical pages, following the specified NUMA policy, to back a
404 * kernel stack.
405 */
406 void
vm_thread_stack_back(struct domainset * ds,vm_offset_t ks,vm_page_t ma[],int npages,int req_class)407 vm_thread_stack_back(struct domainset *ds, vm_offset_t ks, vm_page_t ma[],
408 int npages, int req_class)
409 {
410 vm_pindex_t pindex;
411 int n;
412
413 pindex = atop(ks - VM_MIN_KERNEL_ADDRESS);
414
415 VM_OBJECT_WLOCK(kstack_object);
416 for (n = 0; n < npages;) {
417 if (vm_ndomains > 1)
418 kstack_object->domain.dr_policy = ds;
419
420 /*
421 * Use WAITFAIL to force a reset of the domain selection policy
422 * if we had to sleep for pages.
423 */
424 n += vm_page_grab_pages(kstack_object, pindex + n,
425 req_class | VM_ALLOC_WIRED | VM_ALLOC_WAITFAIL,
426 &ma[n], npages - n);
427 }
428 VM_OBJECT_WUNLOCK(kstack_object);
429 }
430
431 static int
kstack_import(void * arg,void ** store,int cnt,int domain,int flags)432 kstack_import(void *arg, void **store, int cnt, int domain, int flags)
433 {
434 struct domainset *ds;
435 int i;
436
437 if (domain == UMA_ANYDOMAIN)
438 ds = DOMAINSET_RR();
439 else
440 ds = DOMAINSET_PREF(domain);
441
442 for (i = 0; i < cnt; i++) {
443 store[i] = (void *)vm_thread_stack_create(ds, kstack_pages);
444 if (store[i] == NULL)
445 break;
446 }
447 return (i);
448 }
449
450 static void
kstack_release(void * arg,void ** store,int cnt)451 kstack_release(void *arg, void **store, int cnt)
452 {
453 vm_offset_t ks;
454 int i;
455
456 for (i = 0; i < cnt; i++) {
457 ks = (vm_offset_t)store[i];
458 vm_thread_stack_dispose(ks, kstack_pages);
459 }
460 }
461
462 static void
kstack_cache_init(void * null)463 kstack_cache_init(void *null)
464 {
465 kstack_object = vm_object_allocate(OBJT_SWAP,
466 atop(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS));
467 kstack_cache = uma_zcache_create("kstack_cache",
468 kstack_pages * PAGE_SIZE, NULL, NULL, NULL, NULL,
469 kstack_import, kstack_release, NULL,
470 UMA_ZONE_FIRSTTOUCH);
471 kstack_cache_size = imax(128, mp_ncpus * 4);
472 uma_zone_set_maxcache(kstack_cache, kstack_cache_size);
473 }
474 SYSINIT(vm_kstacks, SI_SUB_KMEM, SI_ORDER_ANY, kstack_cache_init, NULL);
475
476 #ifdef KSTACK_USAGE_PROF
477 /*
478 * Track maximum stack used by a thread in kernel.
479 */
480 static int max_kstack_used;
481
482 SYSCTL_INT(_debug, OID_AUTO, max_kstack_used, CTLFLAG_RD,
483 &max_kstack_used, 0,
484 "Maximum stack depth used by a thread in kernel");
485
486 void
intr_prof_stack_use(struct thread * td,struct trapframe * frame)487 intr_prof_stack_use(struct thread *td, struct trapframe *frame)
488 {
489 vm_offset_t stack_top;
490 vm_offset_t current;
491 int used, prev_used;
492
493 /*
494 * Testing for interrupted kernel mode isn't strictly
495 * needed. It optimizes the execution, since interrupts from
496 * usermode will have only the trap frame on the stack.
497 */
498 if (TRAPF_USERMODE(frame))
499 return;
500
501 stack_top = td->td_kstack + td->td_kstack_pages * PAGE_SIZE;
502 current = (vm_offset_t)(uintptr_t)&stack_top;
503
504 /*
505 * Try to detect if interrupt is using kernel thread stack.
506 * Hardware could use a dedicated stack for interrupt handling.
507 */
508 if (stack_top <= current || current < td->td_kstack)
509 return;
510
511 used = stack_top - current;
512 for (;;) {
513 prev_used = max_kstack_used;
514 if (prev_used >= used)
515 break;
516 if (atomic_cmpset_int(&max_kstack_used, prev_used, used))
517 break;
518 }
519 }
520 #endif /* KSTACK_USAGE_PROF */
521
522 /*
523 * Implement fork's actions on an address space.
524 * Here we arrange for the address space to be copied or referenced,
525 * allocate a user struct (pcb and kernel stack), then call the
526 * machine-dependent layer to fill those in and make the new process
527 * ready to run. The new process is set up so that it returns directly
528 * to user mode to avoid stack copying and relocation problems.
529 */
530 int
vm_forkproc(struct thread * td,struct proc * p2,struct thread * td2,struct vmspace * vm2,int flags)531 vm_forkproc(struct thread *td, struct proc *p2, struct thread *td2,
532 struct vmspace *vm2, int flags)
533 {
534 struct proc *p1 = td->td_proc;
535 struct domainset *dset;
536 int error;
537
538 if ((flags & RFPROC) == 0) {
539 /*
540 * Divorce the memory, if it is shared, essentially
541 * this changes shared memory amongst threads, into
542 * COW locally.
543 */
544 if ((flags & RFMEM) == 0) {
545 error = vmspace_unshare(p1);
546 if (error)
547 return (error);
548 }
549 cpu_fork(td, p2, td2, flags);
550 return (0);
551 }
552
553 if (flags & RFMEM) {
554 p2->p_vmspace = p1->p_vmspace;
555 refcount_acquire(&p1->p_vmspace->vm_refcnt);
556 }
557 dset = td2->td_domain.dr_policy;
558 while (vm_page_count_severe_set(&dset->ds_mask)) {
559 vm_wait_doms(&dset->ds_mask, 0);
560 }
561
562 if ((flags & RFMEM) == 0) {
563 p2->p_vmspace = vm2;
564 if (p1->p_vmspace->vm_shm)
565 shmfork(p1, p2);
566 }
567
568 /*
569 * cpu_fork will copy and update the pcb, set up the kernel stack,
570 * and make the child ready to run.
571 */
572 cpu_fork(td, p2, td2, flags);
573 return (0);
574 }
575
576 /*
577 * Called after process has been wait(2)'ed upon and is being reaped.
578 * The idea is to reclaim resources that we could not reclaim while
579 * the process was still executing.
580 */
581 void
vm_waitproc(struct proc * p)582 vm_waitproc(struct proc *p)
583 {
584
585 vmspace_exitfree(p); /* and clean-out the vmspace */
586 }
587
588 void
kick_proc0(void)589 kick_proc0(void)
590 {
591
592 wakeup(&proc0);
593 }
594