1/*
2 * Copyright (c) 1991, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * The Mach Operating System project at Carnegie-Mellon University.
7 *
8 * Redistribution and use in source and binary forms, with or without

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56 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
57 * School of Computer Science
58 * Carnegie Mellon University
59 * Pittsburgh PA 15213-3890
60 *
61 * any improvements or extensions that they make and grant Carnegie the
62 * rights to redistribute these changes.
63 *
64 * $Id: vm_kern.c,v 1.49 1998/08/24 08:39:37 dfr Exp $
65 */
66
67/*
68 * Kernel memory management.
69 */
70
71#include <sys/param.h>
72#include <sys/systm.h>

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176
177 for (i = 0; i < size; i += PAGE_SIZE) {
178 vm_page_t mem;
179
180 mem = vm_page_grab(kernel_object, OFF_TO_IDX(offset + i),
181 VM_ALLOC_ZERO | VM_ALLOC_RETRY);
182 if ((mem->flags & PG_ZERO) == 0)
183 vm_page_zero_fill(mem);
184 vm_page_flag_clear(mem, (PG_BUSY | PG_ZERO));
185 mem->valid = VM_PAGE_BITS_ALL;
186 }
187
188 /*
189 * And finally, mark the data as non-pageable.
190 */
191
192 (void) vm_map_pageable(map, (vm_offset_t) addr, addr + size, FALSE);
193
194 return (addr);
195}
196
197/*
198 * kmem_free:
199 *
200 * Release a region of kernel virtual memory allocated
201 * with kmem_alloc, and return the physical pages
202 * associated with that region.
203 */
204void
205kmem_free(map, addr, size)
206 vm_map_t map;
207 register vm_offset_t addr;
208 vm_size_t size;
209{
210 (void) vm_map_remove(map, trunc_page(addr), round_page(addr + size));

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247 if (result == NULL)
248 panic("kmem_suballoc: cannot create submap");
249 if ((ret = vm_map_submap(parent, *min, *max, result)) != KERN_SUCCESS)
250 panic("kmem_suballoc: unable to change range to submap");
251 return (result);
252}
253
254/*
255 * Allocate wired-down memory in the kernel's address map for the higher
256 * level kernel memory allocator (kern/kern_malloc.c). We cannot use
257 * kmem_alloc() because we may need to allocate memory at interrupt
258 * level where we cannot block (canwait == FALSE).
259 *
260 * This routine has its own private kernel submap (kmem_map) and object
261 * (kmem_object). This, combined with the fact that only malloc uses
262 * this routine, ensures that we will never block in map or object waits.
263 *
264 * Note that this still only works in a uni-processor environment and
265 * when called at splhigh().
266 *
267 * We don't worry about expanding the map (adding entries) since entries
268 * for wired maps are statically allocated.
269 */
270vm_offset_t
271kmem_malloc(map, size, waitflag)
272 register vm_map_t map;
273 register vm_size_t size;
274 boolean_t waitflag;
275{
276 register vm_offset_t offset, i;
277 vm_map_entry_t entry;
278 vm_offset_t addr;
279 vm_page_t m;
280
281 if (map != kmem_map && map != mb_map)
282 panic("kmem_malloc: map != {kmem,mb}_map");

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292 vm_map_lock(map);
293 if (vm_map_findspace(map, vm_map_min(map), size, &addr)) {
294 vm_map_unlock(map);
295 if (map == mb_map) {
296 mb_map_full = TRUE;
297 printf("Out of mbuf clusters - adjust NMBCLUSTERS or increase maxusers!\n");
298 return (0);
299 }
300 if (waitflag == M_WAITOK)
301 panic("kmem_malloc(%d): kmem_map too small: %d total allocated",
302 size, map->size);
303 return (0);
304 }
305 offset = addr - VM_MIN_KERNEL_ADDRESS;
306 vm_object_reference(kmem_object);
307 vm_map_insert(map, kmem_object, offset, addr, addr + size,
308 VM_PROT_ALL, VM_PROT_ALL, 0);
309
310 for (i = 0; i < size; i += PAGE_SIZE) {
311retry:
312 m = vm_page_alloc(kmem_object, OFF_TO_IDX(offset + i),
313 (waitflag == M_NOWAIT) ? VM_ALLOC_INTERRUPT : VM_ALLOC_SYSTEM);
314
315 /*
316 * Ran out of space, free everything up and return. Don't need
317 * to lock page queues here as we know that the pages we got
318 * aren't on any queues.
319 */
320 if (m == NULL) {
321 if (waitflag == M_WAITOK) {
322 VM_WAIT;
323 goto retry;
324 }
325 while (i != 0) {
326 i -= PAGE_SIZE;
327 m = vm_page_lookup(kmem_object,
328 OFF_TO_IDX(offset + i));
329 vm_page_free(m);
330 }
331 vm_map_delete(map, addr, addr + size);
332 vm_map_unlock(map);
333 return (0);
334 }
335 vm_page_flag_clear(m, PG_ZERO);
336 m->valid = VM_PAGE_BITS_ALL;
337 }
338
339 /*
340 * Mark map entry as non-pageable. Assert: vm_map_insert() will never

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354 * Loop thru pages, entering them in the pmap. (We cannot add them to
355 * the wired count without wrapping the vm_page_queue_lock in
356 * splimp...)
357 */
358 for (i = 0; i < size; i += PAGE_SIZE) {
359 m = vm_page_lookup(kmem_object, OFF_TO_IDX(offset + i));
360 vm_page_wire(m);
361 vm_page_wakeup(m);
362 pmap_enter(kernel_pmap, addr + i, VM_PAGE_TO_PHYS(m),
363 VM_PROT_ALL, 1);
364 vm_page_flag_set(m, PG_MAPPED | PG_WRITEABLE | PG_REFERENCED);
365 }
366 vm_map_unlock(map);
367
368 return (addr);
369}
370
371/*
372 * kmem_alloc_wait
373 *
374 * Allocates pageable memory from a sub-map of the kernel. If the submap
375 * has no room, the caller sleeps waiting for more memory in the submap.
376 *
377 */
378vm_offset_t
379kmem_alloc_wait(map, size)
380 vm_map_t map;
381 vm_size_t size;
382{
383 vm_offset_t addr;
384
385 size = round_page(size);

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401 tsleep(map, PVM, "kmaw", 0);
402 }
403 vm_map_insert(map, NULL, (vm_offset_t) 0, addr, addr + size, VM_PROT_ALL, VM_PROT_ALL, 0);
404 vm_map_unlock(map);
405 return (addr);
406}
407
408/*
409 * kmem_free_wakeup
410 *
411 * Returns memory to a submap of the kernel, and wakes up any processes
412 * waiting for memory in that map.
413 */
414void
415kmem_free_wakeup(map, addr, size)
416 vm_map_t map;
417 vm_offset_t addr;
418 vm_size_t size;
419{
420 vm_map_lock(map);
421 (void) vm_map_delete(map, trunc_page(addr), round_page(addr + size));
422 wakeup(map);
423 vm_map_unlock(map);
424}
425
426/*
427 * Create the kernel map; insert a mapping covering kernel text, data, bss,
428 * and all space allocated thus far (`boostrap' data). The new map will thus
429 * map the range between VM_MIN_KERNEL_ADDRESS and `start' as allocated, and
430 * the range between `start' and `end' as free.
431 */
432void
433kmem_init(start, end)
434 vm_offset_t start, end;
435{
436 register vm_map_t m;
437
438 m = vm_map_create(kernel_pmap, VM_MIN_KERNEL_ADDRESS, end);
439 vm_map_lock(m);
440 /* N.B.: cannot use kgdb to debug, starting with this assignment ... */
441 kernel_map = m;
442 kernel_map->system_map = 1;
443 (void) vm_map_insert(m, NULL, (vm_offset_t) 0,
444 VM_MIN_KERNEL_ADDRESS, start, VM_PROT_ALL, VM_PROT_ALL, 0);
445 /* ... and ending with the completion of the above `insert' */
446 vm_map_unlock(m);
447}