xref: /freebsd/sys/vm/vm_glue.c (revision adc56f5a383771f594829b7db9c263b6f0dcf1bd) 
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/domainset.h>
72 #include <sys/limits.h>
73 #include <sys/lock.h>
74 #include <sys/malloc.h>
75 #include <sys/mutex.h>
76 #include <sys/proc.h>
77 #include <sys/racct.h>
78 #include <sys/resourcevar.h>
79 #include <sys/rwlock.h>
80 #include <sys/sched.h>
81 #include <sys/sf_buf.h>
82 #include <sys/shm.h>
83 #include <sys/smp.h>
84 #include <sys/vmmeter.h>
85 #include <sys/vmem.h>
86 #include <sys/sx.h>
87 #include <sys/sysctl.h>
88 #include <sys/eventhandler.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
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
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
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
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
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 	VM_OBJECT_WLOCK(object);
226 	(void)vm_page_grab_valid(&m, object, pindex,
227 	    VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED);
228 	VM_OBJECT_WUNLOCK(object);
229 	return (m);
230 }
231 
232 /*
233  * Return a CPU private mapping to the page at the given offset within the
234  * given object.  The page is pinned before it is mapped.
235  */
236 struct sf_buf *
237 vm_imgact_map_page(vm_object_t object, vm_ooffset_t offset)
238 {
239 	vm_page_t m;
240 
241 	m = vm_imgact_hold_page(object, offset);
242 	if (m == NULL)
243 		return (NULL);
244 	sched_pin();
245 	return (sf_buf_alloc(m, SFB_CPUPRIVATE));
246 }
247 
248 /*
249  * Destroy the given CPU private mapping and unpin the page that it mapped.
250  */
251 void
252 vm_imgact_unmap_page(struct sf_buf *sf)
253 {
254 	vm_page_t m;
255 
256 	m = sf_buf_page(sf);
257 	sf_buf_free(sf);
258 	sched_unpin();
259 	vm_page_unwire(m, PQ_ACTIVE);
260 }
261 
262 void
263 vm_sync_icache(vm_map_t map, vm_offset_t va, vm_offset_t sz)
264 {
265 
266 	pmap_sync_icache(map->pmap, va, sz);
267 }
268 
269 static uma_zone_t kstack_cache;
270 static int kstack_cache_size;
271 static int kstack_domain_iter;
272 
273 static int
274 sysctl_kstack_cache_size(SYSCTL_HANDLER_ARGS)
275 {
276 	int error, newsize;
277 
278 	newsize = kstack_cache_size;
279 	error = sysctl_handle_int(oidp, &newsize, 0, req);
280 	if (error == 0 && req->newptr && newsize != kstack_cache_size)
281 		uma_zone_set_maxcache(kstack_cache, newsize);
282 	return (error);
283 }
284 SYSCTL_PROC(_vm, OID_AUTO, kstack_cache_size, CTLTYPE_INT|CTLFLAG_RW,
285 	&kstack_cache_size, 0, sysctl_kstack_cache_size, "IU",
286 	"Maximum number of cached kernel stacks");
287 
288 /*
289  * Create the kernel stack (including pcb for i386) for a new thread.
290  * This routine directly affects the fork perf for a process and
291  * create performance for a thread.
292  */
293 static vm_offset_t
294 vm_thread_stack_create(struct domainset *ds, vm_object_t *ksobjp, int pages)
295 {
296 	vm_page_t ma[KSTACK_MAX_PAGES];
297 	vm_object_t ksobj;
298 	vm_offset_t ks;
299 	int i;
300 
301 	/*
302 	 * Allocate an object for the kstack.
303 	 */
304 	ksobj = vm_object_allocate(OBJT_DEFAULT, pages);
305 
306 	/*
307 	 * Get a kernel virtual address for this thread's kstack.
308 	 */
309 #if defined(__mips__)
310 	/*
311 	 * We need to align the kstack's mapped address to fit within
312 	 * a single TLB entry.
313 	 */
314 	if (vmem_xalloc(kernel_arena, (pages + KSTACK_GUARD_PAGES) * PAGE_SIZE,
315 	    PAGE_SIZE * 2, 0, 0, VMEM_ADDR_MIN, VMEM_ADDR_MAX,
316 	    M_BESTFIT | M_NOWAIT, &ks)) {
317 		ks = 0;
318 	}
319 #else
320 	ks = kva_alloc((pages + KSTACK_GUARD_PAGES) * PAGE_SIZE);
321 #endif
322 	if (ks == 0) {
323 		printf("%s: kstack allocation failed\n", __func__);
324 		vm_object_deallocate(ksobj);
325 		return (0);
326 	}
327 	if (vm_ndomains > 1) {
328 		ksobj->domain.dr_policy = ds;
329 		ksobj->domain.dr_iter =
330 		    atomic_fetchadd_int(&kstack_domain_iter, 1);
331 	}
332 
333 	if (KSTACK_GUARD_PAGES != 0) {
334 		pmap_qremove(ks, KSTACK_GUARD_PAGES);
335 		ks += KSTACK_GUARD_PAGES * PAGE_SIZE;
336 	}
337 
338 	/*
339 	 * For the length of the stack, link in a real page of ram for each
340 	 * page of stack.
341 	 */
342 	VM_OBJECT_WLOCK(ksobj);
343 	(void)vm_page_grab_pages(ksobj, 0, VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY |
344 	    VM_ALLOC_WIRED, ma, pages);
345 	for (i = 0; i < pages; i++)
346 		ma[i]->valid = VM_PAGE_BITS_ALL;
347 	VM_OBJECT_WUNLOCK(ksobj);
348 	pmap_qenter(ks, ma, pages);
349 	*ksobjp = ksobj;
350 
351 	return (ks);
352 }
353 
354 static void
355 vm_thread_stack_dispose(vm_object_t ksobj, vm_offset_t ks, int pages)
356 {
357 	vm_page_t m;
358 	int i;
359 
360 	pmap_qremove(ks, pages);
361 	VM_OBJECT_WLOCK(ksobj);
362 	for (i = 0; i < pages; i++) {
363 		m = vm_page_lookup(ksobj, i);
364 		if (m == NULL)
365 			panic("%s: kstack already missing?", __func__);
366 		vm_page_unwire_noq(m);
367 		vm_page_free(m);
368 	}
369 	VM_OBJECT_WUNLOCK(ksobj);
370 	vm_object_deallocate(ksobj);
371 	kva_free(ks - (KSTACK_GUARD_PAGES * PAGE_SIZE),
372 	    (pages + KSTACK_GUARD_PAGES) * PAGE_SIZE);
373 }
374 
375 /*
376  * Allocate the kernel stack for a new thread.
377  */
378 int
379 vm_thread_new(struct thread *td, int pages)
380 {
381 	vm_object_t ksobj;
382 	vm_offset_t ks;
383 
384 	/* Bounds check */
385 	if (pages <= 1)
386 		pages = kstack_pages;
387 	else if (pages > KSTACK_MAX_PAGES)
388 		pages = KSTACK_MAX_PAGES;
389 
390 	ks = 0;
391 	ksobj = NULL;
392 	if (pages == kstack_pages && kstack_cache != NULL) {
393 		ks = (vm_offset_t)uma_zalloc(kstack_cache, M_NOWAIT);
394 		if (ks != 0)
395 			ksobj = PHYS_TO_VM_PAGE(pmap_kextract(ks))->object;
396 	}
397 
398 	/*
399 	 * Ensure that kstack objects can draw pages from any memory
400 	 * domain.  Otherwise a local memory shortage can block a process
401 	 * swap-in.
402 	 */
403 	if (ks == 0)
404 		ks = vm_thread_stack_create(DOMAINSET_PREF(PCPU_GET(domain)),
405 		    &ksobj, pages);
406 	if (ks == 0)
407 		return (0);
408 	td->td_kstack_obj = ksobj;
409 	td->td_kstack = ks;
410 	td->td_kstack_pages = pages;
411 	return (1);
412 }
413 
414 /*
415  * Dispose of a thread's kernel stack.
416  */
417 void
418 vm_thread_dispose(struct thread *td)
419 {
420 	vm_object_t ksobj;
421 	vm_offset_t ks;
422 	int pages;
423 
424 	pages = td->td_kstack_pages;
425 	ksobj = td->td_kstack_obj;
426 	ks = td->td_kstack;
427 	td->td_kstack = 0;
428 	td->td_kstack_pages = 0;
429 	if (pages == kstack_pages)
430 		uma_zfree(kstack_cache, (void *)ks);
431 	else
432 		vm_thread_stack_dispose(ksobj, ks, pages);
433 }
434 
435 static int
436 kstack_import(void *arg, void **store, int cnt, int domain, int flags)
437 {
438 	struct domainset *ds;
439 	vm_object_t ksobj;
440 	int i;
441 
442 	if (domain == UMA_ANYDOMAIN)
443 		ds = DOMAINSET_RR();
444 	else
445 		ds = DOMAINSET_PREF(domain);
446 
447 	for (i = 0; i < cnt; i++) {
448 		store[i] = (void *)vm_thread_stack_create(ds, &ksobj,
449 		    kstack_pages);
450 		if (store[i] == NULL)
451 			break;
452 	}
453 	return (i);
454 }
455 
456 static void
457 kstack_release(void *arg, void **store, int cnt)
458 {
459 	vm_offset_t ks;
460 	int i;
461 
462 	for (i = 0; i < cnt; i++) {
463 		ks = (vm_offset_t)store[i];
464 		vm_thread_stack_dispose(
465 		    PHYS_TO_VM_PAGE(pmap_kextract(ks))->object,
466 		    ks, kstack_pages);
467 	}
468 }
469 
470 static void
471 kstack_cache_init(void *null)
472 {
473 	kstack_cache = uma_zcache_create("kstack_cache",
474 	    kstack_pages * PAGE_SIZE, NULL, NULL, NULL, NULL,
475 	    kstack_import, kstack_release, NULL,
476 	    UMA_ZONE_NUMA);
477 	kstack_cache_size = imax(128, mp_ncpus * 4);
478 	uma_zone_set_maxcache(kstack_cache, kstack_cache_size);
479 }
480 
481 SYSINIT(vm_kstacks, SI_SUB_KTHREAD_INIT, SI_ORDER_ANY, kstack_cache_init, NULL);
482 
483 #ifdef KSTACK_USAGE_PROF
484 /*
485  * Track maximum stack used by a thread in kernel.
486  */
487 static int max_kstack_used;
488 
489 SYSCTL_INT(_debug, OID_AUTO, max_kstack_used, CTLFLAG_RD,
490     &max_kstack_used, 0,
491     "Maxiumum stack depth used by a thread in kernel");
492 
493 void
494 intr_prof_stack_use(struct thread *td, struct trapframe *frame)
495 {
496 	vm_offset_t stack_top;
497 	vm_offset_t current;
498 	int used, prev_used;
499 
500 	/*
501 	 * Testing for interrupted kernel mode isn't strictly
502 	 * needed. It optimizes the execution, since interrupts from
503 	 * usermode will have only the trap frame on the stack.
504 	 */
505 	if (TRAPF_USERMODE(frame))
506 		return;
507 
508 	stack_top = td->td_kstack + td->td_kstack_pages * PAGE_SIZE;
509 	current = (vm_offset_t)(uintptr_t)&stack_top;
510 
511 	/*
512 	 * Try to detect if interrupt is using kernel thread stack.
513 	 * Hardware could use a dedicated stack for interrupt handling.
514 	 */
515 	if (stack_top <= current || current < td->td_kstack)
516 		return;
517 
518 	used = stack_top - current;
519 	for (;;) {
520 		prev_used = max_kstack_used;
521 		if (prev_used >= used)
522 			break;
523 		if (atomic_cmpset_int(&max_kstack_used, prev_used, used))
524 			break;
525 	}
526 }
527 #endif /* KSTACK_USAGE_PROF */
528 
529 /*
530  * Implement fork's actions on an address space.
531  * Here we arrange for the address space to be copied or referenced,
532  * allocate a user struct (pcb and kernel stack), then call the
533  * machine-dependent layer to fill those in and make the new process
534  * ready to run.  The new process is set up so that it returns directly
535  * to user mode to avoid stack copying and relocation problems.
536  */
537 int
538 vm_forkproc(struct thread *td, struct proc *p2, struct thread *td2,
539     struct vmspace *vm2, int flags)
540 {
541 	struct proc *p1 = td->td_proc;
542 	struct domainset *dset;
543 	int error;
544 
545 	if ((flags & RFPROC) == 0) {
546 		/*
547 		 * Divorce the memory, if it is shared, essentially
548 		 * this changes shared memory amongst threads, into
549 		 * COW locally.
550 		 */
551 		if ((flags & RFMEM) == 0) {
552 			if (p1->p_vmspace->vm_refcnt > 1) {
553 				error = vmspace_unshare(p1);
554 				if (error)
555 					return (error);
556 			}
557 		}
558 		cpu_fork(td, p2, td2, flags);
559 		return (0);
560 	}
561 
562 	if (flags & RFMEM) {
563 		p2->p_vmspace = p1->p_vmspace;
564 		atomic_add_int(&p1->p_vmspace->vm_refcnt, 1);
565 	}
566 	dset = td2->td_domain.dr_policy;
567 	while (vm_page_count_severe_set(&dset->ds_mask)) {
568 		vm_wait_doms(&dset->ds_mask);
569 	}
570 
571 	if ((flags & RFMEM) == 0) {
572 		p2->p_vmspace = vm2;
573 		if (p1->p_vmspace->vm_shm)
574 			shmfork(p1, p2);
575 	}
576 
577 	/*
578 	 * cpu_fork will copy and update the pcb, set up the kernel stack,
579 	 * and make the child ready to run.
580 	 */
581 	cpu_fork(td, p2, td2, flags);
582 	return (0);
583 }
584 
585 /*
586  * Called after process has been wait(2)'ed upon and is being reaped.
587  * The idea is to reclaim resources that we could not reclaim while
588  * the process was still executing.
589  */
590 void
591 vm_waitproc(p)
592 	struct proc *p;
593 {
594 
595 	vmspace_exitfree(p);		/* and clean-out the vmspace */
596 }
597 
598 void
599 kick_proc0(void)
600 {
601 
602 	wakeup(&proc0);
603 }
604