1 /* $NetBSD: uvm_km.c,v 1.166 2024/12/07 23:19:07 chs Exp $ */
2
3 /*
4 * Copyright (c) 1997 Charles D. Cranor and Washington University.
5 * Copyright (c) 1991, 1993, The Regents of the University of California.
6 *
7 * All rights reserved.
8 *
9 * This code is derived from software contributed to Berkeley by
10 * The Mach Operating System project at Carnegie-Mellon University.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 * @(#)vm_kern.c 8.3 (Berkeley) 1/12/94
37 * from: Id: uvm_km.c,v 1.1.2.14 1998/02/06 05:19:27 chs Exp
38 *
39 *
40 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
41 * All rights reserved.
42 *
43 * Permission to use, copy, modify and distribute this software and
44 * its documentation is hereby granted, provided that both the copyright
45 * notice and this permission notice appear in all copies of the
46 * software, derivative works or modified versions, and any portions
47 * thereof, and that both notices appear in supporting documentation.
48 *
49 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
50 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
51 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
52 *
53 * Carnegie Mellon requests users of this software to return to
54 *
55 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
56 * School of Computer Science
57 * Carnegie Mellon University
58 * Pittsburgh PA 15213-3890
59 *
60 * any improvements or extensions that they make and grant Carnegie the
61 * rights to redistribute these changes.
62 */
63
64 /*
65 * uvm_km.c: handle kernel memory allocation and management
66 */
67
68 /*
69 * overview of kernel memory management:
70 *
71 * the kernel virtual address space is mapped by "kernel_map." kernel_map
72 * starts at VM_MIN_KERNEL_ADDRESS and goes to VM_MAX_KERNEL_ADDRESS.
73 * note that VM_MIN_KERNEL_ADDRESS is equal to vm_map_min(kernel_map).
74 *
75 * the kernel_map has several "submaps." submaps can only appear in
76 * the kernel_map (user processes can't use them). submaps "take over"
77 * the management of a sub-range of the kernel's address space. submaps
78 * are typically allocated at boot time and are never released. kernel
79 * virtual address space that is mapped by a submap is locked by the
80 * submap's lock -- not the kernel_map's lock.
81 *
82 * thus, the useful feature of submaps is that they allow us to break
83 * up the locking and protection of the kernel address space into smaller
84 * chunks.
85 *
86 * the vm system has several standard kernel submaps/arenas, including:
87 * kmem_arena => used for kmem/pool (memoryallocators(9))
88 * pager_map => used to map "buf" structures into kernel space
89 * exec_map => used during exec to handle exec args
90 * etc...
91 *
92 * The kmem_arena is a "special submap", as it lives in a fixed map entry
93 * within the kernel_map and is controlled by vmem(9).
94 *
95 * the kernel allocates its private memory out of special uvm_objects whose
96 * reference count is set to UVM_OBJ_KERN (thus indicating that the objects
97 * are "special" and never die). all kernel objects should be thought of
98 * as large, fixed-sized, sparsely populated uvm_objects. each kernel
99 * object is equal to the size of kernel virtual address space (i.e. the
100 * value "VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS").
101 *
102 * note that just because a kernel object spans the entire kernel virtual
103 * address space doesn't mean that it has to be mapped into the entire space.
104 * large chunks of a kernel object's space go unused either because
105 * that area of kernel VM is unmapped, or there is some other type of
106 * object mapped into that range (e.g. a vnode). for submap's kernel
107 * objects, the only part of the object that can ever be populated is the
108 * offsets that are managed by the submap.
109 *
110 * note that the "offset" in a kernel object is always the kernel virtual
111 * address minus the VM_MIN_KERNEL_ADDRESS (aka vm_map_min(kernel_map)).
112 * example:
113 * suppose VM_MIN_KERNEL_ADDRESS is 0xf8000000 and the kernel does a
114 * uvm_km_alloc(kernel_map, PAGE_SIZE) [allocate 1 wired down page in the
115 * kernel map]. if uvm_km_alloc returns virtual address 0xf8235000,
116 * then that means that the page at offset 0x235000 in kernel_object is
117 * mapped at 0xf8235000.
118 *
119 * kernel object have one other special property: when the kernel virtual
120 * memory mapping them is unmapped, the backing memory in the object is
121 * freed right away. this is done with the uvm_km_pgremove() function.
122 * this has to be done because there is no backing store for kernel pages
123 * and no need to save them after they are no longer referenced.
124 *
125 * Generic arenas:
126 *
127 * kmem_arena:
128 * Main arena controlling the kernel KVA used by other arenas.
129 *
130 * kmem_va_arena:
131 * Implements quantum caching in order to speedup allocations and
132 * reduce fragmentation. The pool(9), unless created with a custom
133 * meta-data allocator, and kmem(9) subsystems use this arena.
134 *
135 * Arenas for meta-data allocations are used by vmem(9) and pool(9).
136 * These arenas cannot use quantum cache. However, kmem_va_meta_arena
137 * compensates this by importing larger chunks from kmem_arena.
138 *
139 * kmem_va_meta_arena:
140 * Space for meta-data.
141 *
142 * kmem_meta_arena:
143 * Imports from kmem_va_meta_arena. Allocations from this arena are
144 * backed with the pages.
145 *
146 * Arena stacking:
147 *
148 * kmem_arena
149 * kmem_va_arena
150 * kmem_va_meta_arena
151 * kmem_meta_arena
152 */
153
154 #include <sys/cdefs.h>
155 __KERNEL_RCSID(0, "$NetBSD: uvm_km.c,v 1.166 2024/12/07 23:19:07 chs Exp $");
156
157 #include "opt_uvmhist.h"
158
159 #include "opt_kmempages.h"
160
161 #ifndef NKMEMPAGES
162 #define NKMEMPAGES 0
163 #endif
164
165 /*
166 * Defaults for lower and upper-bounds for the kmem_arena page count.
167 * Can be overridden by kernel config options.
168 */
169 #ifndef NKMEMPAGES_MIN
170 #define NKMEMPAGES_MIN NKMEMPAGES_MIN_DEFAULT
171 #endif
172
173 #ifndef NKMEMPAGES_MAX
174 #define NKMEMPAGES_MAX NKMEMPAGES_MAX_DEFAULT
175 #endif
176
177
178 #include <sys/param.h>
179 #include <sys/systm.h>
180 #include <sys/atomic.h>
181 #include <sys/proc.h>
182 #include <sys/pool.h>
183 #include <sys/vmem.h>
184 #include <sys/vmem_impl.h>
185 #include <sys/kmem.h>
186 #include <sys/msan.h>
187
188 #include <uvm/uvm.h>
189
190 /*
191 * global data structures
192 */
193
194 struct vm_map *kernel_map = NULL;
195
196 /*
197 * local data structures
198 */
199
200 static struct vm_map kernel_map_store;
201 static struct vm_map_entry kernel_image_mapent_store;
202 static struct vm_map_entry kernel_kmem_mapent_store;
203
204 size_t nkmempages = 0;
205 vaddr_t kmembase;
206 vsize_t kmemsize;
207
208 static struct vmem kmem_arena_store;
209 vmem_t *kmem_arena = NULL;
210 static struct vmem kmem_va_arena_store;
211 vmem_t *kmem_va_arena;
212
213 /*
214 * kmeminit_nkmempages: calculate the size of kmem_arena.
215 */
216 void
kmeminit_nkmempages(void)217 kmeminit_nkmempages(void)
218 {
219 size_t npages;
220
221 if (nkmempages != 0) {
222 /*
223 * It's already been set (by us being here before)
224 * bail out now;
225 */
226 return;
227 }
228
229 #if defined(NKMEMPAGES_MAX_UNLIMITED) && !defined(KMSAN)
230 /*
231 * The extra 1/9 here is to account for uvm_km_va_starved_p()
232 * wanting to keep 10% of kmem virtual space free.
233 * The intent is that on "unlimited" platforms we should be able
234 * to allocate all of physical memory as kmem without behaving
235 * as though we running short of kmem virtual space.
236 */
237 npages = (physmem * 10) / 9;
238 #else
239
240 #if defined(KMSAN)
241 npages = (physmem / 4);
242 #elif defined(PMAP_MAP_POOLPAGE)
243 npages = (physmem / 4);
244 #else
245 npages = (physmem / 3) * 2;
246 #endif /* defined(PMAP_MAP_POOLPAGE) */
247
248 #if !defined(NKMEMPAGES_MAX_UNLIMITED)
249 if (npages > NKMEMPAGES_MAX)
250 npages = NKMEMPAGES_MAX;
251 #endif
252
253 #endif
254
255 if (npages < NKMEMPAGES_MIN)
256 npages = NKMEMPAGES_MIN;
257
258 nkmempages = npages;
259 }
260
261 /*
262 * uvm_km_bootstrap: init kernel maps and objects to reflect reality (i.e.
263 * KVM already allocated for text, data, bss, and static data structures).
264 *
265 * => KVM is defined by VM_MIN_KERNEL_ADDRESS/VM_MAX_KERNEL_ADDRESS.
266 * we assume that [vmin -> start] has already been allocated and that
267 * "end" is the end.
268 */
269
270 void
uvm_km_bootstrap(vaddr_t start,vaddr_t end)271 uvm_km_bootstrap(vaddr_t start, vaddr_t end)
272 {
273 bool kmem_arena_small;
274 vaddr_t base = VM_MIN_KERNEL_ADDRESS;
275 struct uvm_map_args args;
276 int error;
277
278 UVMHIST_FUNC(__func__);
279 UVMHIST_CALLARGS(maphist, "start=%#jx end=%#jx", start, end, 0,0);
280
281 kmeminit_nkmempages();
282 kmemsize = (vsize_t)nkmempages * PAGE_SIZE;
283 kmem_arena_small = kmemsize < 64 * 1024 * 1024;
284
285 UVMHIST_LOG(maphist, "kmemsize=%#jx", kmemsize, 0,0,0);
286
287 /*
288 * next, init kernel memory objects.
289 */
290
291 /* kernel_object: for pageable anonymous kernel memory */
292 uvm_kernel_object = uao_create(VM_MAX_KERNEL_ADDRESS -
293 VM_MIN_KERNEL_ADDRESS, UAO_FLAG_KERNOBJ);
294
295 /*
296 * init the map and reserve any space that might already
297 * have been allocated kernel space before installing.
298 */
299
300 uvm_map_setup(&kernel_map_store, base, end, VM_MAP_PAGEABLE);
301 kernel_map_store.pmap = pmap_kernel();
302 if (start != base) {
303 error = uvm_map_prepare(&kernel_map_store,
304 base, start - base,
305 NULL, UVM_UNKNOWN_OFFSET, 0,
306 UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_NONE,
307 UVM_ADV_RANDOM, UVM_FLAG_FIXED), &args);
308 if (!error) {
309 kernel_image_mapent_store.flags =
310 UVM_MAP_KERNEL | UVM_MAP_STATIC | UVM_MAP_NOMERGE;
311 error = uvm_map_enter(&kernel_map_store, &args,
312 &kernel_image_mapent_store);
313 }
314
315 if (error)
316 panic(
317 "uvm_km_bootstrap: could not reserve space for kernel");
318
319 kmembase = args.uma_start + args.uma_size;
320 } else {
321 kmembase = base;
322 }
323
324 error = uvm_map_prepare(&kernel_map_store,
325 kmembase, kmemsize,
326 NULL, UVM_UNKNOWN_OFFSET, 0,
327 UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_NONE,
328 UVM_ADV_RANDOM, UVM_FLAG_FIXED), &args);
329 if (!error) {
330 kernel_kmem_mapent_store.flags =
331 UVM_MAP_KERNEL | UVM_MAP_STATIC | UVM_MAP_NOMERGE;
332 error = uvm_map_enter(&kernel_map_store, &args,
333 &kernel_kmem_mapent_store);
334 }
335
336 if (error)
337 panic("uvm_km_bootstrap: could not reserve kernel kmem");
338
339 /*
340 * install!
341 */
342
343 kernel_map = &kernel_map_store;
344
345 pool_subsystem_init();
346
347 kmem_arena = vmem_init(&kmem_arena_store, "kmem",
348 kmembase, kmemsize, PAGE_SIZE, NULL, NULL, NULL,
349 0, VM_NOSLEEP | VM_BOOTSTRAP, IPL_VM);
350 #ifdef PMAP_GROWKERNEL
351 /*
352 * kmem_arena VA allocations happen independently of uvm_map.
353 * grow kernel to accommodate the kmem_arena.
354 */
355 if (uvm_maxkaddr < kmembase + kmemsize) {
356 uvm_maxkaddr = pmap_growkernel(kmembase + kmemsize);
357 KASSERTMSG(uvm_maxkaddr >= kmembase + kmemsize,
358 "%#"PRIxVADDR" %#"PRIxVADDR" %#"PRIxVSIZE,
359 uvm_maxkaddr, kmembase, kmemsize);
360 }
361 #endif
362
363 vmem_subsystem_init(kmem_arena);
364
365 UVMHIST_LOG(maphist, "kmem vmem created (base=%#jx, size=%#jx",
366 kmembase, kmemsize, 0,0);
367
368 kmem_va_arena = vmem_init(&kmem_va_arena_store, "kva",
369 0, 0, PAGE_SIZE, vmem_alloc, vmem_free, kmem_arena,
370 (kmem_arena_small ? 4 : VMEM_QCACHE_IDX_MAX) * PAGE_SIZE,
371 VM_NOSLEEP, IPL_VM);
372
373 UVMHIST_LOG(maphist, "<- done", 0,0,0,0);
374 }
375
376 /*
377 * uvm_km_init: init the kernel maps virtual memory caches
378 * and start the pool/kmem allocator.
379 */
380 void
uvm_km_init(void)381 uvm_km_init(void)
382 {
383 kmem_init();
384 }
385
386 /*
387 * uvm_km_suballoc: allocate a submap in the kernel map. once a submap
388 * is allocated all references to that area of VM must go through it. this
389 * allows the locking of VAs in kernel_map to be broken up into regions.
390 *
391 * => if `fixed' is true, *vmin specifies where the region described
392 * pager_map => used to map "buf" structures into kernel space
393 * by the submap must start
394 * => if submap is non NULL we use that as the submap, otherwise we
395 * alloc a new map
396 */
397
398 struct vm_map *
uvm_km_suballoc(struct vm_map * map,vaddr_t * vmin,vaddr_t * vmax,vsize_t size,int flags,bool fixed,struct vm_map * submap)399 uvm_km_suballoc(struct vm_map *map, vaddr_t *vmin /* IN/OUT */,
400 vaddr_t *vmax /* OUT */, vsize_t size, int flags, bool fixed,
401 struct vm_map *submap)
402 {
403 int mapflags = UVM_FLAG_NOMERGE | (fixed ? UVM_FLAG_FIXED : 0);
404 UVMHIST_FUNC(__func__); UVMHIST_CALLED(maphist);
405
406 KASSERT(vm_map_pmap(map) == pmap_kernel());
407
408 size = round_page(size); /* round up to pagesize */
409
410 /*
411 * first allocate a blank spot in the parent map
412 */
413
414 if (uvm_map(map, vmin, size, NULL, UVM_UNKNOWN_OFFSET, 0,
415 UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_NONE,
416 UVM_ADV_RANDOM, mapflags)) != 0) {
417 panic("%s: unable to allocate space in parent map", __func__);
418 }
419
420 /*
421 * set VM bounds (vmin is filled in by uvm_map)
422 */
423
424 *vmax = *vmin + size;
425
426 /*
427 * add references to pmap and create or init the submap
428 */
429
430 pmap_reference(vm_map_pmap(map));
431 if (submap == NULL) {
432 submap = kmem_alloc(sizeof(*submap), KM_SLEEP);
433 }
434 uvm_map_setup(submap, *vmin, *vmax, flags);
435 submap->pmap = vm_map_pmap(map);
436
437 /*
438 * now let uvm_map_submap plug in it...
439 */
440
441 if (uvm_map_submap(map, *vmin, *vmax, submap) != 0)
442 panic("uvm_km_suballoc: submap allocation failed");
443
444 return(submap);
445 }
446
447 /*
448 * uvm_km_pgremove: remove pages from a kernel uvm_object and KVA.
449 */
450
451 void
uvm_km_pgremove(vaddr_t startva,vaddr_t endva)452 uvm_km_pgremove(vaddr_t startva, vaddr_t endva)
453 {
454 struct uvm_object * const uobj = uvm_kernel_object;
455 const voff_t start = startva - vm_map_min(kernel_map);
456 const voff_t end = endva - vm_map_min(kernel_map);
457 struct vm_page *pg;
458 voff_t curoff, nextoff;
459 int swpgonlydelta = 0;
460 UVMHIST_FUNC(__func__); UVMHIST_CALLED(maphist);
461
462 KASSERT(VM_MIN_KERNEL_ADDRESS <= startva);
463 KASSERT(startva < endva);
464 KASSERT(endva <= VM_MAX_KERNEL_ADDRESS);
465
466 rw_enter(uobj->vmobjlock, RW_WRITER);
467 pmap_remove(pmap_kernel(), startva, endva);
468 for (curoff = start; curoff < end; curoff = nextoff) {
469 nextoff = curoff + PAGE_SIZE;
470 pg = uvm_pagelookup(uobj, curoff);
471 if (pg != NULL && pg->flags & PG_BUSY) {
472 uvm_pagewait(pg, uobj->vmobjlock, "km_pgrm");
473 rw_enter(uobj->vmobjlock, RW_WRITER);
474 nextoff = curoff;
475 continue;
476 }
477
478 /*
479 * free the swap slot, then the page.
480 */
481
482 if (pg == NULL &&
483 uao_find_swslot(uobj, curoff >> PAGE_SHIFT) > 0) {
484 swpgonlydelta++;
485 }
486 uao_dropswap(uobj, curoff >> PAGE_SHIFT);
487 if (pg != NULL) {
488 uvm_pagefree(pg);
489 }
490 }
491 rw_exit(uobj->vmobjlock);
492
493 if (swpgonlydelta > 0) {
494 KASSERT(uvmexp.swpgonly >= swpgonlydelta);
495 atomic_add_int(&uvmexp.swpgonly, -swpgonlydelta);
496 }
497 }
498
499
500 /*
501 * uvm_km_pgremove_intrsafe: like uvm_km_pgremove(), but for non object backed
502 * regions.
503 *
504 * => when you unmap a part of anonymous kernel memory you want to toss
505 * the pages right away. (this is called from uvm_unmap_...).
506 * => none of the pages will ever be busy, and none of them will ever
507 * be on the active or inactive queues (because they have no object).
508 */
509
510 void
uvm_km_pgremove_intrsafe(struct vm_map * map,vaddr_t start,vaddr_t end)511 uvm_km_pgremove_intrsafe(struct vm_map *map, vaddr_t start, vaddr_t end)
512 {
513 #define __PGRM_BATCH 16
514 struct vm_page *pg;
515 paddr_t pa[__PGRM_BATCH];
516 int npgrm, i;
517 vaddr_t va, batch_vastart;
518
519 UVMHIST_FUNC(__func__); UVMHIST_CALLED(maphist);
520
521 KASSERT(VM_MAP_IS_KERNEL(map));
522 KASSERTMSG(vm_map_min(map) <= start,
523 "vm_map_min(map) [%#"PRIxVADDR"] <= start [%#"PRIxVADDR"]"
524 " (size=%#"PRIxVSIZE")",
525 vm_map_min(map), start, end - start);
526 KASSERT(start < end);
527 KASSERT(end <= vm_map_max(map));
528
529 for (va = start; va < end;) {
530 batch_vastart = va;
531 /* create a batch of at most __PGRM_BATCH pages to free */
532 for (i = 0;
533 i < __PGRM_BATCH && va < end;
534 va += PAGE_SIZE) {
535 if (!pmap_extract(pmap_kernel(), va, &pa[i])) {
536 continue;
537 }
538 i++;
539 }
540 npgrm = i;
541 /* now remove the mappings */
542 pmap_kremove(batch_vastart, va - batch_vastart);
543 /* and free the pages */
544 for (i = 0; i < npgrm; i++) {
545 pg = PHYS_TO_VM_PAGE(pa[i]);
546 KASSERT(pg);
547 KASSERT(pg->uobject == NULL);
548 KASSERT(pg->uanon == NULL);
549 KASSERT((pg->flags & PG_BUSY) == 0);
550 uvm_pagefree(pg);
551 }
552 }
553 #undef __PGRM_BATCH
554 }
555
556 #if defined(DEBUG)
557 void
uvm_km_check_empty(struct vm_map * map,vaddr_t start,vaddr_t end)558 uvm_km_check_empty(struct vm_map *map, vaddr_t start, vaddr_t end)
559 {
560 vaddr_t va;
561 UVMHIST_FUNC(__func__); UVMHIST_CALLED(maphist);
562
563 KDASSERT(VM_MAP_IS_KERNEL(map));
564 KDASSERT(vm_map_min(map) <= start);
565 KDASSERT(start < end);
566 KDASSERT(end <= vm_map_max(map));
567
568 for (va = start; va < end; va += PAGE_SIZE) {
569 paddr_t pa;
570
571 if (pmap_extract(pmap_kernel(), va, &pa)) {
572 panic("uvm_km_check_empty: va %p has pa %#llx",
573 (void *)va, (long long)pa);
574 }
575 /*
576 * kernel_object should not have pages for the corresponding
577 * region. check it.
578 *
579 * why trylock? because:
580 * - caller might not want to block.
581 * - we can recurse when allocating radix_node for
582 * kernel_object.
583 */
584 if (rw_tryenter(uvm_kernel_object->vmobjlock, RW_READER)) {
585 struct vm_page *pg;
586
587 pg = uvm_pagelookup(uvm_kernel_object,
588 va - vm_map_min(kernel_map));
589 rw_exit(uvm_kernel_object->vmobjlock);
590 if (pg) {
591 panic("uvm_km_check_empty: "
592 "has page hashed at %p",
593 (const void *)va);
594 }
595 }
596 }
597 }
598 #endif /* defined(DEBUG) */
599
600 /*
601 * uvm_km_alloc: allocate an area of kernel memory.
602 *
603 * => NOTE: we can return 0 even if we can wait if there is not enough
604 * free VM space in the map... caller should be prepared to handle
605 * this case.
606 * => we return KVA of memory allocated
607 */
608
609 vaddr_t
uvm_km_alloc(struct vm_map * map,vsize_t size,vsize_t align,uvm_flag_t flags)610 uvm_km_alloc(struct vm_map *map, vsize_t size, vsize_t align, uvm_flag_t flags)
611 {
612 vaddr_t kva, loopva;
613 vaddr_t offset;
614 vsize_t loopsize;
615 struct vm_page *pg;
616 struct uvm_object *obj;
617 int pgaflags;
618 vm_prot_t prot, vaprot;
619 UVMHIST_FUNC(__func__); UVMHIST_CALLED(maphist);
620
621 KASSERT(vm_map_pmap(map) == pmap_kernel());
622 KASSERT((flags & UVM_KMF_TYPEMASK) == UVM_KMF_WIRED ||
623 (flags & UVM_KMF_TYPEMASK) == UVM_KMF_PAGEABLE ||
624 (flags & UVM_KMF_TYPEMASK) == UVM_KMF_VAONLY);
625 KASSERT((flags & UVM_KMF_VAONLY) != 0 || (flags & UVM_KMF_COLORMATCH) == 0);
626 KASSERT((flags & UVM_KMF_COLORMATCH) == 0 || (flags & UVM_KMF_VAONLY) != 0);
627
628 /*
629 * setup for call
630 */
631
632 kva = vm_map_min(map); /* hint */
633 size = round_page(size);
634 obj = (flags & UVM_KMF_PAGEABLE) ? uvm_kernel_object : NULL;
635 UVMHIST_LOG(maphist," (map=%#jx, obj=%#jx, size=%#jx, flags=%#jx)",
636 (uintptr_t)map, (uintptr_t)obj, size, flags);
637
638 /*
639 * allocate some virtual space
640 */
641
642 vaprot = (flags & UVM_KMF_EXEC) ? UVM_PROT_ALL : UVM_PROT_RW;
643 if (__predict_false(uvm_map(map, &kva, size, obj, UVM_UNKNOWN_OFFSET,
644 align, UVM_MAPFLAG(vaprot, UVM_PROT_ALL, UVM_INH_NONE,
645 UVM_ADV_RANDOM,
646 (flags & (UVM_KMF_TRYLOCK | UVM_KMF_NOWAIT | UVM_KMF_WAITVA
647 | UVM_KMF_COLORMATCH)))) != 0)) {
648 UVMHIST_LOG(maphist, "<- done (no VM)",0,0,0,0);
649 return(0);
650 }
651
652 /*
653 * if all we wanted was VA, return now
654 */
655
656 if (flags & (UVM_KMF_VAONLY | UVM_KMF_PAGEABLE)) {
657 UVMHIST_LOG(maphist,"<- done valloc (kva=%#jx)", kva,0,0,0);
658 return(kva);
659 }
660
661 /*
662 * recover object offset from virtual address
663 */
664
665 offset = kva - vm_map_min(kernel_map);
666 UVMHIST_LOG(maphist, " kva=%#jx, offset=%#jx", kva, offset,0,0);
667
668 /*
669 * now allocate and map in the memory... note that we are the only ones
670 * whom should ever get a handle on this area of VM.
671 */
672
673 loopva = kva;
674 loopsize = size;
675
676 pgaflags = UVM_FLAG_COLORMATCH;
677 if (flags & UVM_KMF_NOWAIT)
678 pgaflags |= UVM_PGA_USERESERVE;
679 if (flags & UVM_KMF_ZERO)
680 pgaflags |= UVM_PGA_ZERO;
681 prot = VM_PROT_READ | VM_PROT_WRITE;
682 if (flags & UVM_KMF_EXEC)
683 prot |= VM_PROT_EXECUTE;
684 while (loopsize) {
685 KASSERTMSG(!pmap_extract(pmap_kernel(), loopva, NULL),
686 "loopva=%#"PRIxVADDR, loopva);
687
688 pg = uvm_pagealloc_strat(NULL, offset, NULL, pgaflags,
689 #ifdef UVM_KM_VMFREELIST
690 UVM_PGA_STRAT_ONLY, UVM_KM_VMFREELIST
691 #else
692 UVM_PGA_STRAT_NORMAL, 0
693 #endif
694 );
695
696 /*
697 * out of memory?
698 */
699
700 if (__predict_false(pg == NULL)) {
701 if ((flags & UVM_KMF_NOWAIT) ||
702 ((flags & UVM_KMF_CANFAIL) && !uvm_reclaimable())) {
703 /* free everything! */
704 uvm_km_free(map, kva, size,
705 flags & UVM_KMF_TYPEMASK);
706 return (0);
707 } else {
708 uvm_wait("km_getwait2"); /* sleep here */
709 continue;
710 }
711 }
712
713 pg->flags &= ~PG_BUSY; /* new page */
714 UVM_PAGE_OWN(pg, NULL);
715
716 /*
717 * map it in
718 */
719
720 pmap_kenter_pa(loopva, VM_PAGE_TO_PHYS(pg),
721 prot, PMAP_KMPAGE);
722 loopva += PAGE_SIZE;
723 offset += PAGE_SIZE;
724 loopsize -= PAGE_SIZE;
725 }
726
727 pmap_update(pmap_kernel());
728
729 if ((flags & UVM_KMF_ZERO) == 0) {
730 kmsan_orig((void *)kva, size, KMSAN_TYPE_UVM, __RET_ADDR);
731 kmsan_mark((void *)kva, size, KMSAN_STATE_UNINIT);
732 }
733
734 UVMHIST_LOG(maphist,"<- done (kva=%#jx)", kva,0,0,0);
735 return(kva);
736 }
737
738 /*
739 * uvm_km_protect: change the protection of an allocated area
740 */
741
742 int
uvm_km_protect(struct vm_map * map,vaddr_t addr,vsize_t size,vm_prot_t prot)743 uvm_km_protect(struct vm_map *map, vaddr_t addr, vsize_t size, vm_prot_t prot)
744 {
745 return uvm_map_protect(map, addr, addr + round_page(size), prot, false);
746 }
747
748 /*
749 * uvm_km_free: free an area of kernel memory
750 */
751
752 void
uvm_km_free(struct vm_map * map,vaddr_t addr,vsize_t size,uvm_flag_t flags)753 uvm_km_free(struct vm_map *map, vaddr_t addr, vsize_t size, uvm_flag_t flags)
754 {
755 UVMHIST_FUNC(__func__); UVMHIST_CALLED(maphist);
756
757 KASSERT((flags & UVM_KMF_TYPEMASK) == UVM_KMF_WIRED ||
758 (flags & UVM_KMF_TYPEMASK) == UVM_KMF_PAGEABLE ||
759 (flags & UVM_KMF_TYPEMASK) == UVM_KMF_VAONLY);
760 KASSERT((addr & PAGE_MASK) == 0);
761 KASSERT(vm_map_pmap(map) == pmap_kernel());
762
763 size = round_page(size);
764
765 if (flags & UVM_KMF_PAGEABLE) {
766 uvm_km_pgremove(addr, addr + size);
767 } else if (flags & UVM_KMF_WIRED) {
768 /*
769 * Note: uvm_km_pgremove_intrsafe() extracts mapping, thus
770 * remove it after. See comment below about KVA visibility.
771 */
772 uvm_km_pgremove_intrsafe(map, addr, addr + size);
773 }
774
775 /*
776 * Note: uvm_unmap_remove() calls pmap_update() for us, before
777 * KVA becomes globally available.
778 */
779
780 uvm_unmap1(map, addr, addr + size, UVM_FLAG_VAONLY);
781 }
782
783 /* Sanity; must specify both or none. */
784 #if (defined(PMAP_MAP_POOLPAGE) || defined(PMAP_UNMAP_POOLPAGE)) && \
785 (!defined(PMAP_MAP_POOLPAGE) || !defined(PMAP_UNMAP_POOLPAGE))
786 #error Must specify MAP and UNMAP together.
787 #endif
788
789 #if defined(PMAP_ALLOC_POOLPAGE) && \
790 !defined(PMAP_MAP_POOLPAGE) && !defined(PMAP_UNMAP_POOLPAGE)
791 #error Must specify ALLOC with MAP and UNMAP
792 #endif
793
794 int
uvm_km_kmem_alloc(vmem_t * vm,vmem_size_t size,vm_flag_t flags,vmem_addr_t * addr)795 uvm_km_kmem_alloc(vmem_t *vm, vmem_size_t size, vm_flag_t flags,
796 vmem_addr_t *addr)
797 {
798 struct vm_page *pg;
799 vmem_addr_t va;
800 int rc;
801 vaddr_t loopva;
802 vsize_t loopsize;
803
804 size = round_page(size);
805
806 #if defined(PMAP_MAP_POOLPAGE)
807 if (size == PAGE_SIZE) {
808 again:
809 #ifdef PMAP_ALLOC_POOLPAGE
810 pg = PMAP_ALLOC_POOLPAGE((flags & VM_SLEEP) ?
811 0 : UVM_PGA_USERESERVE);
812 #else
813 pg = uvm_pagealloc(NULL, 0, NULL,
814 (flags & VM_SLEEP) ? 0 : UVM_PGA_USERESERVE);
815 #endif /* PMAP_ALLOC_POOLPAGE */
816 if (__predict_false(pg == NULL)) {
817 if (flags & VM_SLEEP) {
818 uvm_wait("plpg");
819 goto again;
820 }
821 return ENOMEM;
822 }
823 va = PMAP_MAP_POOLPAGE(VM_PAGE_TO_PHYS(pg));
824 KASSERT(va != 0);
825 *addr = va;
826 return 0;
827 }
828 #endif /* PMAP_MAP_POOLPAGE */
829
830 rc = vmem_alloc(vm, size, flags, &va);
831 if (rc != 0)
832 return rc;
833
834 #ifdef PMAP_GROWKERNEL
835 /*
836 * These VA allocations happen independently of uvm_map
837 * so this allocation must not extend beyond the current limit.
838 */
839 KASSERTMSG(uvm_maxkaddr >= va + size,
840 "%#"PRIxVADDR" %#"PRIxPTR" %#zx",
841 uvm_maxkaddr, va, size);
842 #endif
843
844 loopva = va;
845 loopsize = size;
846
847 while (loopsize) {
848 paddr_t pa __diagused;
849 KASSERTMSG(!pmap_extract(pmap_kernel(), loopva, &pa),
850 "loopva=%#"PRIxVADDR" loopsize=%#"PRIxVSIZE
851 " pa=%#"PRIxPADDR" vmem=%p",
852 loopva, loopsize, pa, vm);
853
854 pg = uvm_pagealloc(NULL, loopva, NULL,
855 UVM_FLAG_COLORMATCH
856 | ((flags & VM_SLEEP) ? 0 : UVM_PGA_USERESERVE));
857 if (__predict_false(pg == NULL)) {
858 if (flags & VM_SLEEP) {
859 uvm_wait("plpg");
860 continue;
861 } else {
862 uvm_km_pgremove_intrsafe(kernel_map, va,
863 va + size);
864 vmem_free(vm, va, size);
865 return ENOMEM;
866 }
867 }
868
869 pg->flags &= ~PG_BUSY; /* new page */
870 UVM_PAGE_OWN(pg, NULL);
871 pmap_kenter_pa(loopva, VM_PAGE_TO_PHYS(pg),
872 VM_PROT_READ|VM_PROT_WRITE, PMAP_KMPAGE);
873
874 loopva += PAGE_SIZE;
875 loopsize -= PAGE_SIZE;
876 }
877 pmap_update(pmap_kernel());
878
879 *addr = va;
880
881 return 0;
882 }
883
884 void
uvm_km_kmem_free(vmem_t * vm,vmem_addr_t addr,size_t size)885 uvm_km_kmem_free(vmem_t *vm, vmem_addr_t addr, size_t size)
886 {
887
888 size = round_page(size);
889 #if defined(PMAP_UNMAP_POOLPAGE)
890 if (size == PAGE_SIZE) {
891 paddr_t pa;
892
893 pa = PMAP_UNMAP_POOLPAGE(addr);
894 uvm_pagefree(PHYS_TO_VM_PAGE(pa));
895 return;
896 }
897 #endif /* PMAP_UNMAP_POOLPAGE */
898 uvm_km_pgremove_intrsafe(kernel_map, addr, addr + size);
899 pmap_update(pmap_kernel());
900
901 vmem_free(vm, addr, size);
902 }
903
904 bool
uvm_km_va_starved_p(void)905 uvm_km_va_starved_p(void)
906 {
907 vmem_size_t total;
908 vmem_size_t free;
909
910 if (kmem_arena == NULL)
911 return false;
912
913 total = vmem_size(kmem_arena, VMEM_ALLOC|VMEM_FREE);
914 free = vmem_size(kmem_arena, VMEM_FREE);
915
916 return (free < (total / 10));
917 }
918