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