xref: /freebsd/sys/vm/vm_glue.c (revision 6be3386466ab79a84b48429ae66244f21526d3df) 
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/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/eventhandler.h>
90 #include <sys/kernel.h>
91 #include <sys/ktr.h>
92 #include <sys/unistd.h>
93 
94 #include <vm/uma.h>
95 #include <vm/vm.h>
96 #include <vm/vm_param.h>
97 #include <vm/pmap.h>
98 #include <vm/vm_domainset.h>
99 #include <vm/vm_map.h>
100 #include <vm/vm_page.h>
101 #include <vm/vm_pageout.h>
102 #include <vm/vm_object.h>
103 #include <vm/vm_kern.h>
104 #include <vm/vm_extern.h>
105 #include <vm/vm_pager.h>
106 #include <vm/swap_pager.h>
107 
108 #include <machine/cpu.h>
109 
110 /*
111  * MPSAFE
112  *
113  * WARNING!  This code calls vm_map_check_protection() which only checks
114  * the associated vm_map_entry range.  It does not determine whether the
115  * contents of the memory is actually readable or writable.  In most cases
116  * just checking the vm_map_entry is sufficient within the kernel's address
117  * space.
118  */
119 int
120 kernacc(void *addr, int len, int rw)
121 {
122 	boolean_t rv;
123 	vm_offset_t saddr, eaddr;
124 	vm_prot_t prot;
125 
126 	KASSERT((rw & ~VM_PROT_ALL) == 0,
127 	    ("illegal ``rw'' argument to kernacc (%x)\n", rw));
128 
129 	if ((vm_offset_t)addr + len > vm_map_max(kernel_map) ||
130 	    (vm_offset_t)addr + len < (vm_offset_t)addr)
131 		return (FALSE);
132 
133 	prot = rw;
134 	saddr = trunc_page((vm_offset_t)addr);
135 	eaddr = round_page((vm_offset_t)addr + len);
136 	vm_map_lock_read(kernel_map);
137 	rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot);
138 	vm_map_unlock_read(kernel_map);
139 	return (rv == TRUE);
140 }
141 
142 /*
143  * MPSAFE
144  *
145  * WARNING!  This code calls vm_map_check_protection() which only checks
146  * the associated vm_map_entry range.  It does not determine whether the
147  * contents of the memory is actually readable or writable.  vmapbuf(),
148  * vm_fault_quick(), or copyin()/copout()/su*()/fu*() functions should be
149  * used in conjunction with this call.
150  */
151 int
152 useracc(void *addr, int len, int 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_user_wired)
187 		return (ENOMEM);
188 	error = vm_map_wire(&curproc->p_vmspace->vm_map, start, end,
189 	    VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES);
190 	if (error == KERN_SUCCESS) {
191 		curthread->td_vslock_sz += len;
192 		return (0);
193 	}
194 
195 	/*
196 	 * Return EFAULT on error to match copy{in,out}() behaviour
197 	 * rather than returning ENOMEM like mlock() would.
198 	 */
199 	return (EFAULT);
200 }
201 
202 void
203 vsunlock(void *addr, size_t len)
204 {
205 
206 	/* Rely on the parameter sanity checks performed by vslock(). */
207 	MPASS(curthread->td_vslock_sz >= len);
208 	curthread->td_vslock_sz -= len;
209 	(void)vm_map_unwire(&curproc->p_vmspace->vm_map,
210 	    trunc_page((vm_offset_t)addr), round_page((vm_offset_t)addr + len),
211 	    VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES);
212 }
213 
214 /*
215  * Pin the page contained within the given object at the given offset.  If the
216  * page is not resident, allocate and load it using the given object's pager.
217  * Return the pinned page if successful; otherwise, return NULL.
218  */
219 static vm_page_t
220 vm_imgact_hold_page(vm_object_t object, vm_ooffset_t offset)
221 {
222 	vm_page_t m;
223 	vm_pindex_t pindex;
224 
225 	pindex = OFF_TO_IDX(offset);
226 	(void)vm_page_grab_valid_unlocked(&m, object, pindex,
227 	    VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED);
228 	return (m);
229 }
230 
231 /*
232  * Return a CPU private mapping to the page at the given offset within the
233  * given object.  The page is pinned before it is mapped.
234  */
235 struct sf_buf *
236 vm_imgact_map_page(vm_object_t object, vm_ooffset_t offset)
237 {
238 	vm_page_t m;
239 
240 	m = vm_imgact_hold_page(object, offset);
241 	if (m == NULL)
242 		return (NULL);
243 	sched_pin();
244 	return (sf_buf_alloc(m, SFB_CPUPRIVATE));
245 }
246 
247 /*
248  * Destroy the given CPU private mapping and unpin the page that it mapped.
249  */
250 void
251 vm_imgact_unmap_page(struct sf_buf *sf)
252 {
253 	vm_page_t m;
254 
255 	m = sf_buf_page(sf);
256 	sf_buf_free(sf);
257 	sched_unpin();
258 	vm_page_unwire(m, PQ_ACTIVE);
259 }
260 
261 void
262 vm_sync_icache(vm_map_t map, vm_offset_t va, vm_offset_t sz)
263 {
264 
265 	pmap_sync_icache(map->pmap, va, sz);
266 }
267 
268 vm_object_t kstack_object;
269 static uma_zone_t kstack_cache;
270 static int kstack_cache_size;
271 
272 static int
273 sysctl_kstack_cache_size(SYSCTL_HANDLER_ARGS)
274 {
275 	int error, oldsize;
276 
277 	oldsize = kstack_cache_size;
278 	error = sysctl_handle_int(oidp, arg1, arg2, req);
279 	if (error == 0 && req->newptr && oldsize != kstack_cache_size)
280 		uma_zone_set_maxcache(kstack_cache, kstack_cache_size);
281 	return (error);
282 }
283 SYSCTL_PROC(_vm, OID_AUTO, kstack_cache_size,
284     CTLTYPE_INT|CTLFLAG_MPSAFE|CTLFLAG_RW, &kstack_cache_size, 0,
285     sysctl_kstack_cache_size, "IU", "Maximum number of cached kernel stacks");
286 
287 /*
288  * Create the kernel stack (including pcb for i386) for a new thread.
289  */
290 static vm_offset_t
291 vm_thread_stack_create(struct domainset *ds, int pages)
292 {
293 	vm_page_t ma[KSTACK_MAX_PAGES];
294 	vm_offset_t ks;
295 	int i;
296 
297 	/*
298 	 * Get a kernel virtual address for this thread's kstack.
299 	 */
300 #if defined(__mips__)
301 	/*
302 	 * We need to align the kstack's mapped address to fit within
303 	 * a single TLB entry.
304 	 */
305 	if (vmem_xalloc(kernel_arena, (pages + KSTACK_GUARD_PAGES) * PAGE_SIZE,
306 	    PAGE_SIZE * 2, 0, 0, VMEM_ADDR_MIN, VMEM_ADDR_MAX,
307 	    M_BESTFIT | M_NOWAIT, &ks)) {
308 		ks = 0;
309 	}
310 #else
311 	ks = kva_alloc((pages + KSTACK_GUARD_PAGES) * PAGE_SIZE);
312 #endif
313 	if (ks == 0) {
314 		printf("%s: kstack allocation failed\n", __func__);
315 		return (0);
316 	}
317 
318 	if (KSTACK_GUARD_PAGES != 0) {
319 		pmap_qremove(ks, KSTACK_GUARD_PAGES);
320 		ks += KSTACK_GUARD_PAGES * PAGE_SIZE;
321 	}
322 
323 	/*
324 	 * Allocate physical pages to back the stack.
325 	 */
326 	vm_thread_stack_back(ds, ks, ma, pages, VM_ALLOC_NORMAL);
327 	for (i = 0; i < pages; i++)
328 		vm_page_valid(ma[i]);
329 	pmap_qenter(ks, ma, pages);
330 
331 	return (ks);
332 }
333 
334 static void
335 vm_thread_stack_dispose(vm_offset_t ks, int pages)
336 {
337 	vm_page_t m;
338 	vm_pindex_t pindex;
339 	int i;
340 
341 	pindex = atop(ks - VM_MIN_KERNEL_ADDRESS);
342 
343 	pmap_qremove(ks, pages);
344 	VM_OBJECT_WLOCK(kstack_object);
345 	for (i = 0; i < pages; i++) {
346 		m = vm_page_lookup(kstack_object, pindex + i);
347 		if (m == NULL)
348 			panic("%s: kstack already missing?", __func__);
349 		vm_page_xbusy_claim(m);
350 		vm_page_unwire_noq(m);
351 		vm_page_free(m);
352 	}
353 	VM_OBJECT_WUNLOCK(kstack_object);
354 	kva_free(ks - (KSTACK_GUARD_PAGES * PAGE_SIZE),
355 	    (pages + KSTACK_GUARD_PAGES) * PAGE_SIZE);
356 }
357 
358 /*
359  * Allocate the kernel stack for a new thread.
360  */
361 int
362 vm_thread_new(struct thread *td, int pages)
363 {
364 	vm_offset_t ks;
365 
366 	/* Bounds check */
367 	if (pages <= 1)
368 		pages = kstack_pages;
369 	else if (pages > KSTACK_MAX_PAGES)
370 		pages = KSTACK_MAX_PAGES;
371 
372 	ks = 0;
373 	if (pages == kstack_pages && kstack_cache != NULL)
374 		ks = (vm_offset_t)uma_zalloc(kstack_cache, M_NOWAIT);
375 
376 	/*
377 	 * Ensure that kstack objects can draw pages from any memory
378 	 * domain.  Otherwise a local memory shortage can block a process
379 	 * swap-in.
380 	 */
381 	if (ks == 0)
382 		ks = vm_thread_stack_create(DOMAINSET_PREF(PCPU_GET(domain)),
383 		    pages);
384 	if (ks == 0)
385 		return (0);
386 	td->td_kstack = ks;
387 	td->td_kstack_pages = pages;
388 	return (1);
389 }
390 
391 /*
392  * Dispose of a thread's kernel stack.
393  */
394 void
395 vm_thread_dispose(struct thread *td)
396 {
397 	vm_offset_t ks;
398 	int pages;
399 
400 	pages = td->td_kstack_pages;
401 	ks = td->td_kstack;
402 	td->td_kstack = 0;
403 	td->td_kstack_pages = 0;
404 	if (pages == kstack_pages)
405 		uma_zfree(kstack_cache, (void *)ks);
406 	else
407 		vm_thread_stack_dispose(ks, pages);
408 }
409 
410 /*
411  * Allocate physical pages, following the specified NUMA policy, to back a
412  * kernel stack.
413  */
414 void
415 vm_thread_stack_back(struct domainset *ds, vm_offset_t ks, vm_page_t ma[],
416     int npages, int req_class)
417 {
418 	vm_pindex_t pindex;
419 	int n;
420 
421 	pindex = atop(ks - VM_MIN_KERNEL_ADDRESS);
422 
423 	VM_OBJECT_WLOCK(kstack_object);
424 	for (n = 0; n < npages;) {
425 		if (vm_ndomains > 1)
426 			kstack_object->domain.dr_policy = ds;
427 
428 		/*
429 		 * Use WAITFAIL to force a reset of the domain selection policy
430 		 * if we had to sleep for pages.
431 		 */
432 		n += vm_page_grab_pages(kstack_object, pindex + n,
433 		    req_class | VM_ALLOC_WIRED | VM_ALLOC_WAITFAIL,
434 		    &ma[n], npages - n);
435 	}
436 	VM_OBJECT_WUNLOCK(kstack_object);
437 }
438 
439 static int
440 kstack_import(void *arg, void **store, int cnt, int domain, int flags)
441 {
442 	struct domainset *ds;
443 	int i;
444 
445 	if (domain == UMA_ANYDOMAIN)
446 		ds = DOMAINSET_RR();
447 	else
448 		ds = DOMAINSET_PREF(domain);
449 
450 	for (i = 0; i < cnt; i++) {
451 		store[i] = (void *)vm_thread_stack_create(ds, kstack_pages);
452 		if (store[i] == NULL)
453 			break;
454 	}
455 	return (i);
456 }
457 
458 static void
459 kstack_release(void *arg, void **store, int cnt)
460 {
461 	vm_offset_t ks;
462 	int i;
463 
464 	for (i = 0; i < cnt; i++) {
465 		ks = (vm_offset_t)store[i];
466 		vm_thread_stack_dispose(ks, kstack_pages);
467 	}
468 }
469 
470 static void
471 kstack_cache_init(void *null)
472 {
473 	kstack_object = vm_object_allocate(OBJT_SWAP,
474 	    atop(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS));
475 	kstack_cache = uma_zcache_create("kstack_cache",
476 	    kstack_pages * PAGE_SIZE, NULL, NULL, NULL, NULL,
477 	    kstack_import, kstack_release, NULL,
478 	    UMA_ZONE_FIRSTTOUCH);
479 	kstack_cache_size = imax(128, mp_ncpus * 4);
480 	uma_zone_set_maxcache(kstack_cache, kstack_cache_size);
481 }
482 SYSINIT(vm_kstacks, SI_SUB_KMEM, SI_ORDER_ANY, kstack_cache_init, NULL);
483 
484 #ifdef KSTACK_USAGE_PROF
485 /*
486  * Track maximum stack used by a thread in kernel.
487  */
488 static int max_kstack_used;
489 
490 SYSCTL_INT(_debug, OID_AUTO, max_kstack_used, CTLFLAG_RD,
491     &max_kstack_used, 0,
492     "Maxiumum stack depth used by a thread in kernel");
493 
494 void
495 intr_prof_stack_use(struct thread *td, struct trapframe *frame)
496 {
497 	vm_offset_t stack_top;
498 	vm_offset_t current;
499 	int used, prev_used;
500 
501 	/*
502 	 * Testing for interrupted kernel mode isn't strictly
503 	 * needed. It optimizes the execution, since interrupts from
504 	 * usermode will have only the trap frame on the stack.
505 	 */
506 	if (TRAPF_USERMODE(frame))
507 		return;
508 
509 	stack_top = td->td_kstack + td->td_kstack_pages * PAGE_SIZE;
510 	current = (vm_offset_t)(uintptr_t)&stack_top;
511 
512 	/*
513 	 * Try to detect if interrupt is using kernel thread stack.
514 	 * Hardware could use a dedicated stack for interrupt handling.
515 	 */
516 	if (stack_top <= current || current < td->td_kstack)
517 		return;
518 
519 	used = stack_top - current;
520 	for (;;) {
521 		prev_used = max_kstack_used;
522 		if (prev_used >= used)
523 			break;
524 		if (atomic_cmpset_int(&max_kstack_used, prev_used, used))
525 			break;
526 	}
527 }
528 #endif /* KSTACK_USAGE_PROF */
529 
530 /*
531  * Implement fork's actions on an address space.
532  * Here we arrange for the address space to be copied or referenced,
533  * allocate a user struct (pcb and kernel stack), then call the
534  * machine-dependent layer to fill those in and make the new process
535  * ready to run.  The new process is set up so that it returns directly
536  * to user mode to avoid stack copying and relocation problems.
537  */
538 int
539 vm_forkproc(struct thread *td, struct proc *p2, struct thread *td2,
540     struct vmspace *vm2, int flags)
541 {
542 	struct proc *p1 = td->td_proc;
543 	struct domainset *dset;
544 	int error;
545 
546 	if ((flags & RFPROC) == 0) {
547 		/*
548 		 * Divorce the memory, if it is shared, essentially
549 		 * this changes shared memory amongst threads, into
550 		 * COW locally.
551 		 */
552 		if ((flags & RFMEM) == 0) {
553 			if (refcount_load(&p1->p_vmspace->vm_refcnt) > 1) {
554 				error = vmspace_unshare(p1);
555 				if (error)
556 					return (error);
557 			}
558 		}
559 		cpu_fork(td, p2, td2, flags);
560 		return (0);
561 	}
562 
563 	if (flags & RFMEM) {
564 		p2->p_vmspace = p1->p_vmspace;
565 		refcount_acquire(&p1->p_vmspace->vm_refcnt);
566 	}
567 	dset = td2->td_domain.dr_policy;
568 	while (vm_page_count_severe_set(&dset->ds_mask)) {
569 		vm_wait_doms(&dset->ds_mask, 0);
570 	}
571 
572 	if ((flags & RFMEM) == 0) {
573 		p2->p_vmspace = vm2;
574 		if (p1->p_vmspace->vm_shm)
575 			shmfork(p1, p2);
576 	}
577 
578 	/*
579 	 * cpu_fork will copy and update the pcb, set up the kernel stack,
580 	 * and make the child ready to run.
581 	 */
582 	cpu_fork(td, p2, td2, flags);
583 	return (0);
584 }
585 
586 /*
587  * Called after process has been wait(2)'ed upon and is being reaped.
588  * The idea is to reclaim resources that we could not reclaim while
589  * the process was still executing.
590  */
591 void
592 vm_waitproc(p)
593 	struct proc *p;
594 {
595 
596 	vmspace_exitfree(p);		/* and clean-out the vmspace */
597 }
598 
599 void
600 kick_proc0(void)
601 {
602 
603 	wakeup(&proc0);
604 }
605