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 > 0
110 #define KVA_KSTACK_QUANTUM_SHIFT (VM_LEVEL_0_ORDER + PAGE_SHIFT)
111 #else
112 #define KVA_KSTACK_QUANTUM_SHIFT (8 + PAGE_SHIFT)
113 #endif
114 #define KVA_KSTACK_QUANTUM (1ul << KVA_KSTACK_QUANTUM_SHIFT)
115
116 /*
117 * MPSAFE
118 *
119 * WARNING! This code calls vm_map_check_protection() which only checks
120 * the associated vm_map_entry range. It does not determine whether the
121 * contents of the memory is actually readable or writable. In most cases
122 * just checking the vm_map_entry is sufficient within the kernel's address
123 * space.
124 */
125 int
kernacc(void * addr,int len,int rw)126 kernacc(void *addr, int len, int rw)
127 {
128 boolean_t rv;
129 vm_offset_t saddr, eaddr;
130 vm_prot_t prot;
131
132 KASSERT((rw & ~VM_PROT_ALL) == 0,
133 ("illegal ``rw'' argument to kernacc (%x)\n", rw));
134
135 if ((vm_offset_t)addr + len > vm_map_max(kernel_map) ||
136 (vm_offset_t)addr + len < (vm_offset_t)addr)
137 return (FALSE);
138
139 prot = rw;
140 saddr = trunc_page((vm_offset_t)addr);
141 eaddr = round_page((vm_offset_t)addr + len);
142 vm_map_lock_read(kernel_map);
143 rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot);
144 vm_map_unlock_read(kernel_map);
145 return (rv == TRUE);
146 }
147
148 /*
149 * MPSAFE
150 *
151 * WARNING! This code calls vm_map_check_protection() which only checks
152 * the associated vm_map_entry range. It does not determine whether the
153 * contents of the memory is actually readable or writable. vmapbuf(),
154 * vm_fault_quick(), or copyin()/copout()/su*()/fu*() functions should be
155 * used in conjunction with this call.
156 */
157 int
useracc(void * addr,int len,int rw)158 useracc(void *addr, int len, int rw)
159 {
160 boolean_t rv;
161 vm_prot_t prot;
162 vm_map_t map;
163
164 KASSERT((rw & ~VM_PROT_ALL) == 0,
165 ("illegal ``rw'' argument to useracc (%x)\n", rw));
166 prot = rw;
167 map = &curproc->p_vmspace->vm_map;
168 if ((vm_offset_t)addr + len > vm_map_max(map) ||
169 (vm_offset_t)addr + len < (vm_offset_t)addr) {
170 return (FALSE);
171 }
172 vm_map_lock_read(map);
173 rv = vm_map_check_protection(map, trunc_page((vm_offset_t)addr),
174 round_page((vm_offset_t)addr + len), prot);
175 vm_map_unlock_read(map);
176 return (rv == TRUE);
177 }
178
179 int
vslock(void * addr,size_t len)180 vslock(void *addr, size_t len)
181 {
182 vm_offset_t end, last, start;
183 vm_size_t npages;
184 int error;
185
186 last = (vm_offset_t)addr + len;
187 start = trunc_page((vm_offset_t)addr);
188 end = round_page(last);
189 if (last < (vm_offset_t)addr || end < (vm_offset_t)addr)
190 return (EINVAL);
191 npages = atop(end - start);
192 if (npages > vm_page_max_user_wired)
193 return (ENOMEM);
194 error = vm_map_wire(&curproc->p_vmspace->vm_map, start, end,
195 VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES);
196 if (error == KERN_SUCCESS) {
197 curthread->td_vslock_sz += len;
198 return (0);
199 }
200
201 /*
202 * Return EFAULT on error to match copy{in,out}() behaviour
203 * rather than returning ENOMEM like mlock() would.
204 */
205 return (EFAULT);
206 }
207
208 void
vsunlock(void * addr,size_t len)209 vsunlock(void *addr, size_t len)
210 {
211
212 /* Rely on the parameter sanity checks performed by vslock(). */
213 MPASS(curthread->td_vslock_sz >= len);
214 curthread->td_vslock_sz -= len;
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
vm_imgact_hold_page(vm_object_t object,vm_ooffset_t offset)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
231 pindex = OFF_TO_IDX(offset);
232 (void)vm_page_grab_valid_unlocked(&m, object, pindex,
233 VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED);
234 return (m);
235 }
236
237 /*
238 * Return a CPU private mapping to the page at the given offset within the
239 * given object. The page is pinned before it is mapped.
240 */
241 struct sf_buf *
vm_imgact_map_page(vm_object_t object,vm_ooffset_t offset)242 vm_imgact_map_page(vm_object_t object, vm_ooffset_t offset)
243 {
244 vm_page_t m;
245
246 m = vm_imgact_hold_page(object, offset);
247 if (m == NULL)
248 return (NULL);
249 sched_pin();
250 return (sf_buf_alloc(m, SFB_CPUPRIVATE));
251 }
252
253 /*
254 * Destroy the given CPU private mapping and unpin the page that it mapped.
255 */
256 void
vm_imgact_unmap_page(struct sf_buf * sf)257 vm_imgact_unmap_page(struct sf_buf *sf)
258 {
259 vm_page_t m;
260
261 m = sf_buf_page(sf);
262 sf_buf_free(sf);
263 sched_unpin();
264 vm_page_unwire(m, PQ_ACTIVE);
265 }
266
267 void
vm_sync_icache(vm_map_t map,vm_offset_t va,vm_offset_t sz)268 vm_sync_icache(vm_map_t map, vm_offset_t va, vm_offset_t sz)
269 {
270
271 pmap_sync_icache(map->pmap, va, sz);
272 }
273
274 static vm_object_t kstack_object;
275 static vm_object_t kstack_alt_object;
276 static uma_zone_t kstack_cache;
277 static int kstack_cache_size;
278 static vmem_t *vmd_kstack_arena[MAXMEMDOM];
279
280 static int
sysctl_kstack_cache_size(SYSCTL_HANDLER_ARGS)281 sysctl_kstack_cache_size(SYSCTL_HANDLER_ARGS)
282 {
283 int error, oldsize;
284
285 oldsize = kstack_cache_size;
286 error = sysctl_handle_int(oidp, arg1, arg2, req);
287 if (error == 0 && req->newptr && oldsize != kstack_cache_size)
288 uma_zone_set_maxcache(kstack_cache, kstack_cache_size);
289 return (error);
290 }
291 SYSCTL_PROC(_vm, OID_AUTO, kstack_cache_size,
292 CTLTYPE_INT|CTLFLAG_MPSAFE|CTLFLAG_RW, &kstack_cache_size, 0,
293 sysctl_kstack_cache_size, "IU", "Maximum number of cached kernel stacks");
294
295 /*
296 * Allocate a virtual address range from a domain kstack arena, following
297 * the specified NUMA policy.
298 */
299 static vm_offset_t
vm_thread_alloc_kstack_kva(vm_size_t size,int domain)300 vm_thread_alloc_kstack_kva(vm_size_t size, int domain)
301 {
302 #ifndef __ILP32__
303 int rv;
304 vmem_t *arena;
305 vm_offset_t addr = 0;
306
307 size = round_page(size);
308 /* Allocate from the kernel arena for non-standard kstack sizes. */
309 if (size != ptoa(kstack_pages + KSTACK_GUARD_PAGES)) {
310 arena = vm_dom[domain].vmd_kernel_arena;
311 } else {
312 arena = vmd_kstack_arena[domain];
313 }
314 rv = vmem_alloc(arena, size, M_BESTFIT | M_NOWAIT, &addr);
315 if (rv == ENOMEM)
316 return (0);
317 KASSERT(atop(addr - VM_MIN_KERNEL_ADDRESS) %
318 (kstack_pages + KSTACK_GUARD_PAGES) == 0,
319 ("%s: allocated kstack KVA not aligned to multiple of kstack size",
320 __func__));
321
322 return (addr);
323 #else
324 return (kva_alloc(size));
325 #endif
326 }
327
328 /*
329 * Release a region of kernel virtual memory
330 * allocated from the kstack arena.
331 */
332 static __noinline void
vm_thread_free_kstack_kva(vm_offset_t addr,vm_size_t size,int domain)333 vm_thread_free_kstack_kva(vm_offset_t addr, vm_size_t size, int domain)
334 {
335 vmem_t *arena;
336
337 size = round_page(size);
338 #ifdef __ILP32__
339 arena = kernel_arena;
340 #else
341 arena = vmd_kstack_arena[domain];
342 if (size != ptoa(kstack_pages + KSTACK_GUARD_PAGES)) {
343 arena = vm_dom[domain].vmd_kernel_arena;
344 }
345 #endif
346 vmem_free(arena, addr, size);
347 }
348
349 static vmem_size_t
vm_thread_kstack_import_quantum(void)350 vm_thread_kstack_import_quantum(void)
351 {
352 #ifndef __ILP32__
353 /*
354 * The kstack_quantum is larger than KVA_QUANTUM to account
355 * for holes induced by guard pages.
356 */
357 return (KVA_KSTACK_QUANTUM * (kstack_pages + KSTACK_GUARD_PAGES));
358 #else
359 return (KVA_KSTACK_QUANTUM);
360 #endif
361 }
362
363 /*
364 * Import KVA from a parent arena into the kstack arena. Imports must be
365 * a multiple of kernel stack pages + guard pages in size.
366 *
367 * Kstack VA allocations need to be aligned so that the linear KVA pindex
368 * is divisible by the total number of kstack VA pages. This is necessary to
369 * make vm_kstack_pindex work properly.
370 *
371 * We import a multiple of KVA_KSTACK_QUANTUM-sized region from the parent
372 * arena. The actual size used by the kstack arena is one kstack smaller to
373 * allow for the necessary alignment adjustments to be made.
374 */
375 static int
vm_thread_kstack_arena_import(void * arena,vmem_size_t size,int flags,vmem_addr_t * addrp)376 vm_thread_kstack_arena_import(void *arena, vmem_size_t size, int flags,
377 vmem_addr_t *addrp)
378 {
379 int error, rem;
380 size_t kpages = kstack_pages + KSTACK_GUARD_PAGES;
381
382 KASSERT(atop(size) % kpages == 0,
383 ("%s: Size %jd is not a multiple of kstack pages (%d)", __func__,
384 (intmax_t)size, (int)kpages));
385
386 error = vmem_xalloc(arena, vm_thread_kstack_import_quantum(),
387 KVA_KSTACK_QUANTUM, 0, 0, VMEM_ADDR_MIN, VMEM_ADDR_MAX, flags,
388 addrp);
389 if (error) {
390 return (error);
391 }
392
393 rem = atop(*addrp - VM_MIN_KERNEL_ADDRESS) % kpages;
394 if (rem != 0) {
395 /* Bump addr to next aligned address */
396 *addrp = *addrp + (kpages - rem) * PAGE_SIZE;
397 }
398
399 return (0);
400 }
401
402 /*
403 * Release KVA from a parent arena into the kstack arena. Released imports must
404 * be a multiple of kernel stack pages + guard pages in size.
405 */
406 static void
vm_thread_kstack_arena_release(void * arena,vmem_addr_t addr,vmem_size_t size)407 vm_thread_kstack_arena_release(void *arena, vmem_addr_t addr, vmem_size_t size)
408 {
409 int rem;
410 size_t kpages __diagused = kstack_pages + KSTACK_GUARD_PAGES;
411
412 KASSERT(size % kpages == 0,
413 ("%s: Size %jd is not a multiple of kstack pages (%d)", __func__,
414 (intmax_t)size, (int)kpages));
415
416 KASSERT((addr - VM_MIN_KERNEL_ADDRESS) % kpages == 0,
417 ("%s: Address %p is not properly aligned (%p)", __func__,
418 (void *)addr, (void *)VM_MIN_KERNEL_ADDRESS));
419 /*
420 * If the address is not KVA_KSTACK_QUANTUM-aligned we have to decrement
421 * it to account for the shift in kva_import_kstack.
422 */
423 rem = addr % KVA_KSTACK_QUANTUM;
424 if (rem) {
425 KASSERT(rem <= ptoa(kpages),
426 ("%s: rem > kpages (%d), (%d)", __func__, rem,
427 (int)kpages));
428 addr -= rem;
429 }
430 vmem_xfree(arena, addr, vm_thread_kstack_import_quantum());
431 }
432
433 /*
434 * Create the kernel stack for a new thread.
435 */
436 static vm_offset_t
vm_thread_stack_create(struct domainset * ds,int pages)437 vm_thread_stack_create(struct domainset *ds, int pages)
438 {
439 vm_page_t ma[KSTACK_MAX_PAGES];
440 struct vm_domainset_iter di;
441 int req = VM_ALLOC_NORMAL;
442 vm_object_t obj;
443 vm_offset_t ks;
444 int domain, i;
445
446 obj = vm_thread_kstack_size_to_obj(pages);
447 if (vm_ndomains > 1)
448 obj->domain.dr_policy = ds;
449 vm_domainset_iter_page_init(&di, obj, 0, &domain, &req);
450 do {
451 /*
452 * Get a kernel virtual address for this thread's kstack.
453 */
454 ks = vm_thread_alloc_kstack_kva(ptoa(pages + KSTACK_GUARD_PAGES),
455 domain);
456 if (ks == 0)
457 continue;
458 ks += ptoa(KSTACK_GUARD_PAGES);
459
460 /*
461 * Allocate physical pages to back the stack.
462 */
463 if (vm_thread_stack_back(ks, ma, pages, req, domain) != 0) {
464 vm_thread_free_kstack_kva(ks - ptoa(KSTACK_GUARD_PAGES),
465 ptoa(pages + KSTACK_GUARD_PAGES), domain);
466 continue;
467 }
468 if (KSTACK_GUARD_PAGES != 0) {
469 pmap_qremove(ks - ptoa(KSTACK_GUARD_PAGES),
470 KSTACK_GUARD_PAGES);
471 }
472 for (i = 0; i < pages; i++)
473 vm_page_valid(ma[i]);
474 pmap_qenter(ks, ma, pages);
475 return (ks);
476 } while (vm_domainset_iter_page(&di, obj, &domain) == 0);
477
478 return (0);
479 }
480
481 static __noinline void
vm_thread_stack_dispose(vm_offset_t ks,int pages)482 vm_thread_stack_dispose(vm_offset_t ks, int pages)
483 {
484 vm_page_t m;
485 vm_pindex_t pindex;
486 int i, domain;
487 vm_object_t obj = vm_thread_kstack_size_to_obj(pages);
488
489 pindex = vm_kstack_pindex(ks, pages);
490 domain = vm_phys_domain(vtophys(ks));
491 pmap_qremove(ks, pages);
492 VM_OBJECT_WLOCK(obj);
493 for (i = 0; i < pages; i++) {
494 m = vm_page_lookup(obj, pindex + i);
495 if (m == NULL)
496 panic("%s: kstack already missing?", __func__);
497 KASSERT(vm_page_domain(m) == domain,
498 ("%s: page %p domain mismatch, expected %d got %d",
499 __func__, m, domain, vm_page_domain(m)));
500 vm_page_xbusy_claim(m);
501 vm_page_unwire_noq(m);
502 vm_page_free(m);
503 }
504 VM_OBJECT_WUNLOCK(obj);
505 kasan_mark((void *)ks, ptoa(pages), ptoa(pages), 0);
506 vm_thread_free_kstack_kva(ks - (KSTACK_GUARD_PAGES * PAGE_SIZE),
507 ptoa(pages + KSTACK_GUARD_PAGES), domain);
508 }
509
510 /*
511 * Allocate the kernel stack for a new thread.
512 */
513 int
vm_thread_new(struct thread * td,int pages)514 vm_thread_new(struct thread *td, int pages)
515 {
516 vm_offset_t ks;
517 u_short ks_domain;
518
519 /* Bounds check */
520 if (pages <= 1)
521 pages = kstack_pages;
522 else if (pages > KSTACK_MAX_PAGES)
523 pages = KSTACK_MAX_PAGES;
524
525 ks = 0;
526 if (pages == kstack_pages && kstack_cache != NULL)
527 ks = (vm_offset_t)uma_zalloc(kstack_cache, M_NOWAIT);
528
529 /*
530 * Ensure that kstack objects can draw pages from any memory
531 * domain. Otherwise a local memory shortage can block a process
532 * swap-in.
533 */
534 if (ks == 0)
535 ks = vm_thread_stack_create(DOMAINSET_PREF(PCPU_GET(domain)),
536 pages);
537 if (ks == 0)
538 return (0);
539
540 ks_domain = vm_phys_domain(vtophys(ks));
541 KASSERT(ks_domain >= 0 && ks_domain < vm_ndomains,
542 ("%s: invalid domain for kstack %p", __func__, (void *)ks));
543 td->td_kstack = ks;
544 td->td_kstack_pages = pages;
545 td->td_kstack_domain = ks_domain;
546 return (1);
547 }
548
549 /*
550 * Dispose of a thread's kernel stack.
551 */
552 void
vm_thread_dispose(struct thread * td)553 vm_thread_dispose(struct thread *td)
554 {
555 vm_offset_t ks;
556 int pages;
557
558 pages = td->td_kstack_pages;
559 ks = td->td_kstack;
560 td->td_kstack = 0;
561 td->td_kstack_pages = 0;
562 td->td_kstack_domain = MAXMEMDOM;
563 if (pages == kstack_pages) {
564 kasan_mark((void *)ks, 0, ptoa(pages), KASAN_KSTACK_FREED);
565 uma_zfree(kstack_cache, (void *)ks);
566 } else {
567 vm_thread_stack_dispose(ks, pages);
568 }
569 }
570
571 /*
572 * Calculate kstack pindex.
573 *
574 * Uses a non-identity mapping if guard pages are
575 * active to avoid pindex holes in the kstack object.
576 */
577 vm_pindex_t
vm_kstack_pindex(vm_offset_t ks,int kpages)578 vm_kstack_pindex(vm_offset_t ks, int kpages)
579 {
580 vm_pindex_t pindex = atop(ks - VM_MIN_KERNEL_ADDRESS);
581
582 #ifdef __ILP32__
583 return (pindex);
584 #else
585 /*
586 * Return the linear pindex if guard pages aren't active or if we are
587 * allocating a non-standard kstack size.
588 */
589 if (KSTACK_GUARD_PAGES == 0 || kpages != kstack_pages) {
590 return (pindex);
591 }
592 KASSERT(pindex % (kpages + KSTACK_GUARD_PAGES) >= KSTACK_GUARD_PAGES,
593 ("%s: Attempting to calculate kstack guard page pindex", __func__));
594
595 return (pindex -
596 (pindex / (kpages + KSTACK_GUARD_PAGES) + 1) * KSTACK_GUARD_PAGES);
597 #endif
598 }
599
600 /*
601 * Allocate physical pages, following the specified NUMA policy, to back a
602 * kernel stack.
603 */
604 int
vm_thread_stack_back(vm_offset_t ks,vm_page_t ma[],int npages,int req_class,int domain)605 vm_thread_stack_back(vm_offset_t ks, vm_page_t ma[], int npages, int req_class,
606 int domain)
607 {
608 vm_object_t obj = vm_thread_kstack_size_to_obj(npages);
609 vm_pindex_t pindex;
610 vm_page_t m;
611 int n;
612
613 pindex = vm_kstack_pindex(ks, npages);
614
615 VM_OBJECT_WLOCK(obj);
616 for (n = 0; n < npages;) {
617 m = vm_page_grab(obj, pindex + n,
618 VM_ALLOC_NOCREAT | VM_ALLOC_WIRED);
619 if (m == NULL) {
620 m = vm_page_alloc_domain(obj, pindex + n, domain,
621 req_class | VM_ALLOC_WIRED);
622 }
623 if (m == NULL)
624 break;
625 ma[n++] = m;
626 }
627 if (n < npages)
628 goto cleanup;
629 VM_OBJECT_WUNLOCK(obj);
630
631 return (0);
632 cleanup:
633 for (int i = 0; i < n; i++) {
634 m = ma[i];
635 (void)vm_page_unwire_noq(m);
636 vm_page_free(m);
637 }
638 VM_OBJECT_WUNLOCK(obj);
639
640 return (ENOMEM);
641 }
642
643 vm_object_t
vm_thread_kstack_size_to_obj(int npages)644 vm_thread_kstack_size_to_obj(int npages)
645 {
646 return (npages == kstack_pages ? kstack_object : kstack_alt_object);
647 }
648
649 static int
kstack_import(void * arg,void ** store,int cnt,int domain,int flags)650 kstack_import(void *arg, void **store, int cnt, int domain, int flags)
651 {
652 struct domainset *ds;
653 int i;
654
655 if (domain == UMA_ANYDOMAIN)
656 ds = DOMAINSET_RR();
657 else
658 ds = DOMAINSET_PREF(domain);
659
660 for (i = 0; i < cnt; i++) {
661 store[i] = (void *)vm_thread_stack_create(ds, kstack_pages);
662 if (store[i] == NULL)
663 break;
664 }
665 return (i);
666 }
667
668 static void
kstack_release(void * arg,void ** store,int cnt)669 kstack_release(void *arg, void **store, int cnt)
670 {
671 vm_offset_t ks;
672 int i;
673
674 for (i = 0; i < cnt; i++) {
675 ks = (vm_offset_t)store[i];
676 vm_thread_stack_dispose(ks, kstack_pages);
677 }
678 }
679
680 static void
kstack_cache_init(void * null)681 kstack_cache_init(void *null)
682 {
683 vm_size_t kstack_quantum;
684 int domain;
685
686 kstack_object = vm_object_allocate(OBJT_SWAP,
687 atop(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS));
688 kstack_cache = uma_zcache_create("kstack_cache",
689 kstack_pages * PAGE_SIZE, NULL, NULL, NULL, NULL,
690 kstack_import, kstack_release, NULL,
691 UMA_ZONE_FIRSTTOUCH);
692 kstack_cache_size = imax(128, mp_ncpus * 4);
693 uma_zone_set_maxcache(kstack_cache, kstack_cache_size);
694
695 kstack_alt_object = vm_object_allocate(OBJT_SWAP,
696 atop(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS));
697
698 kstack_quantum = vm_thread_kstack_import_quantum();
699 /*
700 * Reduce size used by the kstack arena to allow for
701 * alignment adjustments in vm_thread_kstack_arena_import.
702 */
703 kstack_quantum -= (kstack_pages + KSTACK_GUARD_PAGES) * PAGE_SIZE;
704 /*
705 * Create the kstack_arena for each domain and set kernel_arena as
706 * parent.
707 */
708 for (domain = 0; domain < vm_ndomains; domain++) {
709 vmd_kstack_arena[domain] = vmem_create("kstack arena", 0, 0,
710 PAGE_SIZE, 0, M_WAITOK);
711 KASSERT(vmd_kstack_arena[domain] != NULL,
712 ("%s: failed to create domain %d kstack_arena", __func__,
713 domain));
714 vmem_set_import(vmd_kstack_arena[domain],
715 vm_thread_kstack_arena_import,
716 vm_thread_kstack_arena_release,
717 vm_dom[domain].vmd_kernel_arena, kstack_quantum);
718 }
719 }
720 SYSINIT(vm_kstacks, SI_SUB_KMEM, SI_ORDER_ANY, kstack_cache_init, NULL);
721
722 #ifdef KSTACK_USAGE_PROF
723 /*
724 * Track maximum stack used by a thread in kernel.
725 */
726 static int max_kstack_used;
727
728 SYSCTL_INT(_debug, OID_AUTO, max_kstack_used, CTLFLAG_RD,
729 &max_kstack_used, 0,
730 "Maximum stack depth used by a thread in kernel");
731
732 void
intr_prof_stack_use(struct thread * td,struct trapframe * frame)733 intr_prof_stack_use(struct thread *td, struct trapframe *frame)
734 {
735 vm_offset_t stack_top;
736 vm_offset_t current;
737 int used, prev_used;
738
739 /*
740 * Testing for interrupted kernel mode isn't strictly
741 * needed. It optimizes the execution, since interrupts from
742 * usermode will have only the trap frame on the stack.
743 */
744 if (TRAPF_USERMODE(frame))
745 return;
746
747 stack_top = td->td_kstack + td->td_kstack_pages * PAGE_SIZE;
748 current = (vm_offset_t)(uintptr_t)&stack_top;
749
750 /*
751 * Try to detect if interrupt is using kernel thread stack.
752 * Hardware could use a dedicated stack for interrupt handling.
753 */
754 if (stack_top <= current || current < td->td_kstack)
755 return;
756
757 used = stack_top - current;
758 for (;;) {
759 prev_used = max_kstack_used;
760 if (prev_used >= used)
761 break;
762 if (atomic_cmpset_int(&max_kstack_used, prev_used, used))
763 break;
764 }
765 }
766 #endif /* KSTACK_USAGE_PROF */
767
768 /*
769 * Implement fork's actions on an address space.
770 * Here we arrange for the address space to be copied or referenced,
771 * allocate a user struct (pcb and kernel stack), then call the
772 * machine-dependent layer to fill those in and make the new process
773 * ready to run. The new process is set up so that it returns directly
774 * to user mode to avoid stack copying and relocation problems.
775 */
776 int
vm_forkproc(struct thread * td,struct proc * p2,struct thread * td2,struct vmspace * vm2,int flags)777 vm_forkproc(struct thread *td, struct proc *p2, struct thread *td2,
778 struct vmspace *vm2, int flags)
779 {
780 struct proc *p1 = td->td_proc;
781 struct domainset *dset;
782 int error;
783
784 if ((flags & RFPROC) == 0) {
785 /*
786 * Divorce the memory, if it is shared, essentially
787 * this changes shared memory amongst threads, into
788 * COW locally.
789 */
790 if ((flags & RFMEM) == 0) {
791 error = vmspace_unshare(p1);
792 if (error)
793 return (error);
794 }
795 cpu_fork(td, p2, td2, flags);
796 return (0);
797 }
798
799 if (flags & RFMEM) {
800 p2->p_vmspace = p1->p_vmspace;
801 refcount_acquire(&p1->p_vmspace->vm_refcnt);
802 }
803 dset = td2->td_domain.dr_policy;
804 while (vm_page_count_severe_set(&dset->ds_mask)) {
805 vm_wait_doms(&dset->ds_mask, 0);
806 }
807
808 if ((flags & RFMEM) == 0) {
809 p2->p_vmspace = vm2;
810 if (p1->p_vmspace->vm_shm)
811 shmfork(p1, p2);
812 }
813
814 /*
815 * cpu_fork will copy and update the pcb, set up the kernel stack,
816 * and make the child ready to run.
817 */
818 cpu_fork(td, p2, td2, flags);
819 return (0);
820 }
821
822 /*
823 * Called after process has been wait(2)'ed upon and is being reaped.
824 * The idea is to reclaim resources that we could not reclaim while
825 * the process was still executing.
826 */
827 void
vm_waitproc(struct proc * p)828 vm_waitproc(struct proc *p)
829 {
830
831 vmspace_exitfree(p); /* and clean-out the vmspace */
832 }
833
834 void
kick_proc0(void)835 kick_proc0(void)
836 {
837
838 wakeup(&proc0);
839 }
840