+/*
+ * Copyright (c) 1991 Regents of the University of California.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * The Mach Operating System project at Carnegie-Mellon University.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * This product includes software developed by the University of
+ * California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * @(#)vm_kern.c 7.4 (Berkeley) 5/7/91
+ *
+ *
+ * Copyright (c) 1987, 1990 Carnegie-Mellon University.
+ * All rights reserved.
+ *
+ * Authors: Avadis Tevanian, Jr., Michael Wayne Young
+ *
+ * Permission to use, copy, modify and distribute this software and
+ * its documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ *
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
+ * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
+ * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * Carnegie Mellon requests users of this software to return to
+ *
+ * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
+ * School of Computer Science
+ * Carnegie Mellon University
+ * Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie the
+ * rights to redistribute these changes.
+ */
+
+/*
+ * Kernel memory management.
+ */
+
+#include "param.h"
+
+#include "vm.h"
+#include "vm_page.h"
+#include "vm_pageout.h"
+#include "vm_kern.h"
+
+/*
+ * kmem_alloc_pageable:
+ *
+ * Allocate pageable memory to the kernel's address map.
+ * map must be "kernel_map" below.
+ */
+
+vm_offset_t kmem_alloc_pageable(map, size)
+ vm_map_t map;
+ register vm_size_t size;
+{
+ vm_offset_t addr;
+ register int result;
+
+#if 0
+ if (map != kernel_map)
+ panic("kmem_alloc_pageable: not called with kernel_map");
+#endif 0
+
+ size = round_page(size);
+
+ addr = vm_map_min(map);
+ result = vm_map_find(map, NULL, (vm_offset_t) 0,
+ &addr, size, TRUE);
+ if (result != KERN_SUCCESS) {
+ return(0);
+ }
+
+ return(addr);
+}
+
+/*
+ * Allocate wired-down memory in the kernel's address map
+ * or a submap.
+ */
+vm_offset_t kmem_alloc(map, size)
+ register vm_map_t map;
+ register vm_size_t size;
+{
+ vm_offset_t addr;
+ register int result;
+ register vm_offset_t offset;
+ extern vm_object_t kernel_object;
+ vm_offset_t i;
+
+ size = round_page(size);
+
+ /*
+ * Use the kernel object for wired-down kernel pages.
+ * Assume that no region of the kernel object is
+ * referenced more than once.
+ */
+
+ addr = vm_map_min(map);
+ result = vm_map_find(map, NULL, (vm_offset_t) 0,
+ &addr, size, TRUE);
+ if (result != KERN_SUCCESS) {
+ return(0);
+ }
+
+ /*
+ * Since we didn't know where the new region would
+ * start, we couldn't supply the correct offset into
+ * the kernel object. Re-allocate that address
+ * region with the correct offset.
+ */
+
+ offset = addr - VM_MIN_KERNEL_ADDRESS;
+ vm_object_reference(kernel_object);
+
+ vm_map_lock(map);
+ vm_map_delete(map, addr, addr + size);
+ vm_map_insert(map, kernel_object, offset, addr, addr + size);
+ vm_map_unlock(map);
+
+ /*
+ * Guarantee that there are pages already in this object
+ * before calling vm_map_pageable. This is to prevent the
+ * following scenario:
+ *
+ * 1) Threads have swapped out, so that there is a
+ * pager for the kernel_object.
+ * 2) The kmsg zone is empty, and so we are kmem_allocing
+ * a new page for it.
+ * 3) vm_map_pageable calls vm_fault; there is no page,
+ * but there is a pager, so we call
+ * pager_data_request. But the kmsg zone is empty,
+ * so we must kmem_alloc.
+ * 4) goto 1
+ * 5) Even if the kmsg zone is not empty: when we get
+ * the data back from the pager, it will be (very
+ * stale) non-zero data. kmem_alloc is defined to
+ * return zero-filled memory.
+ *
+ * We're intentionally not activating the pages we allocate
+ * to prevent a race with page-out. vm_map_pageable will wire
+ * the pages.
+ */
+
+ vm_object_lock(kernel_object);
+ for (i = 0 ; i < size; i+= PAGE_SIZE) {
+ vm_page_t mem;
+
+ while ((mem = vm_page_alloc(kernel_object, offset+i)) == NULL) {
+ vm_object_unlock(kernel_object);
+ VM_WAIT;
+ vm_object_lock(kernel_object);
+ }
+ vm_page_zero_fill(mem);
+ mem->busy = FALSE;
+ }
+ vm_object_unlock(kernel_object);
+
+ /*
+ * And finally, mark the data as non-pageable.
+ */
+
+ (void) vm_map_pageable(map, (vm_offset_t) addr, addr + size, FALSE);
+
+ /*
+ * Try to coalesce the map
+ */
+
+ vm_map_simplify(map, addr);
+
+ return(addr);
+}
+
+/*
+ * kmem_free:
+ *
+ * Release a region of kernel virtual memory allocated
+ * with kmem_alloc, and return the physical pages
+ * associated with that region.
+ */
+void kmem_free(map, addr, size)
+ vm_map_t map;
+ register vm_offset_t addr;
+ vm_size_t size;
+{
+ (void) vm_map_remove(map, trunc_page(addr), round_page(addr + size));
+}
+
+/*
+ * kmem_suballoc:
+ *
+ * Allocates a map to manage a subrange
+ * of the kernel virtual address space.
+ *
+ * Arguments are as follows:
+ *
+ * parent Map to take range from
+ * size Size of range to find
+ * min, max Returned endpoints of map
+ * pageable Can the region be paged
+ */
+vm_map_t kmem_suballoc(parent, min, max, size, pageable)
+ register vm_map_t parent;
+ vm_offset_t *min, *max;
+ register vm_size_t size;
+ boolean_t pageable;
+{
+ register int ret;
+ vm_map_t result;
+
+ size = round_page(size);
+
+ *min = (vm_offset_t) vm_map_min(parent);
+ ret = vm_map_find(parent, NULL, (vm_offset_t) 0,
+ min, size, TRUE);
+ if (ret != KERN_SUCCESS) {
+ printf("kmem_suballoc: bad status return of %d.\n", ret);
+ panic("kmem_suballoc");
+ }
+ *max = *min + size;
+ pmap_reference(vm_map_pmap(parent));
+ result = vm_map_create(vm_map_pmap(parent), *min, *max, pageable);
+ if (result == NULL)
+ panic("kmem_suballoc: cannot create submap");
+ if ((ret = vm_map_submap(parent, *min, *max, result)) != KERN_SUCCESS)
+ panic("kmem_suballoc: unable to change range to submap");
+ return(result);
+}
+
+/*
+ * vm_move:
+ *
+ * Move memory from source to destination map, possibly deallocating
+ * the source map reference to the memory.
+ *
+ * Parameters are as follows:
+ *
+ * src_map Source address map
+ * src_addr Address within source map
+ * dst_map Destination address map
+ * num_bytes Amount of data (in bytes) to copy/move
+ * src_dealloc Should source be removed after copy?
+ *
+ * Assumes the src and dst maps are not already locked.
+ *
+ * Returns new destination address or 0 (if a failure occurs).
+ */
+vm_offset_t vm_move(src_map,src_addr,dst_map,num_bytes,src_dealloc)
+ vm_map_t src_map;
+ register vm_offset_t src_addr;
+ register vm_map_t dst_map;
+ vm_offset_t num_bytes;
+ boolean_t src_dealloc;
+{
+ register vm_offset_t src_start; /* Beginning of region */
+ register vm_size_t src_size; /* Size of rounded region */
+ vm_offset_t dst_start; /* destination address */
+ register int result;
+
+ /*
+ * Page-align the source region
+ */
+
+ src_start = trunc_page(src_addr);
+ src_size = round_page(src_addr + num_bytes) - src_start;
+
+ /*
+ * If there's no destination, we can be at most deallocating
+ * the source range.
+ */
+ if (dst_map == NULL) {
+ if (src_dealloc)
+ if (vm_deallocate(src_map, src_start, src_size)
+ != KERN_SUCCESS) {
+ printf("vm_move: deallocate of source");
+ printf(" failed, dealloc_only clause\n");
+ }
+ return(0);
+ }
+
+ /*
+ * Allocate a place to put the copy
+ */
+
+ dst_start = (vm_offset_t) 0;
+ if ((result = vm_allocate(dst_map, &dst_start, src_size, TRUE))
+ == KERN_SUCCESS) {
+ /*
+ * Perform the copy, asking for deallocation if desired
+ */
+ result = vm_map_copy(dst_map, src_map, dst_start, src_size,
+ src_start, FALSE, src_dealloc);
+ }
+
+ /*
+ * Return the destination address corresponding to
+ * the source address given (rather than the front
+ * of the newly-allocated page).
+ */
+
+ if (result == KERN_SUCCESS)
+ return(dst_start + (src_addr - src_start));
+ return(0);
+}
+
+/*
+ * Allocate wired-down memory in the kernel's address map for the higher
+ * level kernel memory allocator (kern/kern_malloc.c). We cannot use
+ * kmem_alloc() because we may need to allocate memory at interrupt
+ * level where we cannot block (canwait == FALSE).
+ *
+ * This routine has its own private kernel submap (kmem_map) and object
+ * (kmem_object). This, combined with the fact that only malloc uses
+ * this routine, ensures that we will never block in map or object waits.
+ *
+ * Note that this still only works in a uni-processor environment and
+ * when called at splhigh().
+ *
+ * We don't worry about expanding the map (adding entries) since entries
+ * for wired maps are statically allocated.
+ */
+vm_offset_t
+kmem_malloc(map, size, canwait)
+ register vm_map_t map;
+ register vm_size_t size;
+ boolean_t canwait;
+{
+ register vm_offset_t offset, i;
+ vm_map_entry_t entry;
+ vm_offset_t addr;
+ vm_page_t m;
+ extern vm_object_t kmem_object;
+
+ if (map != kmem_map && map != mb_map && map != buffer_map)
+ panic("kern_malloc_alloc: map != {kmem,mb,buffer}_map");
+
+ size = round_page(size);
+ addr = vm_map_min(map);
+
+ if (vm_map_find(map, NULL, (vm_offset_t)0,
+ &addr, size, TRUE) != KERN_SUCCESS) {
+ if (canwait)
+ panic("kmem_malloc: kmem_map too small");
+ return(0);
+ }
+
+ /*
+ * Since we didn't know where the new region would start,
+ * we couldn't supply the correct offset into the kmem object.
+ * Re-allocate that address region with the correct offset.
+ */
+ offset = addr - vm_map_min(kmem_map);
+ vm_object_reference(kmem_object);
+
+ vm_map_lock(map);
+ vm_map_delete(map, addr, addr + size);
+ vm_map_insert(map, kmem_object, offset, addr, addr + size);
+
+ /*
+ * If we can wait, just mark the range as wired
+ * (will fault pages as necessary).
+ */
+ if (canwait) {
+ vm_map_unlock(map);
+ (void) vm_map_pageable(map, (vm_offset_t) addr, addr + size,
+ FALSE);
+ vm_map_simplify(map, addr);
+ return(addr);
+ }
+
+ /*
+ * If we cannot wait then we must allocate all memory up front,
+ * pulling it off the active queue to prevent pageout.
+ */
+ vm_object_lock(kmem_object);
+ for (i = 0; i < size; i += PAGE_SIZE) {
+ m = vm_page_alloc(kmem_object, offset + i);
+
+ /*
+ * Ran out of space, free everything up and return.
+ * Don't need to lock page queues here as we know
+ * that the pages we got aren't on any queues.
+ */
+ if (m == NULL) {
+ while (i != 0) {
+ i -= PAGE_SIZE;
+ m = vm_page_lookup(kmem_object, offset + i);
+ vm_page_free(m);
+ }
+ vm_object_unlock(kmem_object);
+ vm_map_delete(map, addr, addr + size);
+ vm_map_unlock(map);
+ return(0);
+ }
+#if 0
+ vm_page_zero_fill(m);
+#endif
+ m->busy = FALSE;
+ }
+ vm_object_unlock(kmem_object);
+
+ /*
+ * Mark map entry as non-pageable.
+ * Assert: vm_map_insert() will never be able to extend the previous
+ * entry so there will be a new entry exactly corresponding to this
+ * address range and it will have wired_count == 0.
+ */
+ if (!vm_map_lookup_entry(map, addr, &entry) ||
+ entry->start != addr || entry->end != addr + size ||
+ entry->wired_count)
+ panic("kmem_malloc: entry not found or misaligned");
+ entry->wired_count++;
+
+ /*
+ * Loop thru pages, entering them in the pmap.
+ * (We cannot add them to the wired count without
+ * wrapping the vm_page_queue_lock in splimp...)
+ */
+ for (i = 0; i < size; i += PAGE_SIZE) {
+ vm_object_lock(kmem_object);
+ m = vm_page_lookup(kmem_object, offset + i);
+ vm_object_unlock(kmem_object);
+ pmap_enter(map->pmap, addr + i, VM_PAGE_TO_PHYS(m),
+ VM_PROT_DEFAULT, TRUE);
+ }
+ vm_map_unlock(map);
+
+ vm_map_simplify(map, addr);
+ return(addr);
+}
+
+/*
+ * kmem_alloc_wait
+ *
+ * Allocates pageable memory from a sub-map of the kernel. If the submap
+ * has no room, the caller sleeps waiting for more memory in the submap.
+ *
+ */
+vm_offset_t kmem_alloc_wait(map, size)
+ vm_map_t map;
+ vm_size_t size;
+{
+ vm_offset_t addr;
+ int result;
+
+ size = round_page(size);
+
+ do {
+ /*
+ * To make this work for more than one map,
+ * use the map's lock to lock out sleepers/wakers.
+ * Unfortunately, vm_map_find also grabs the map lock.
+ */
+ vm_map_lock(map);
+ lock_set_recursive(&map->lock);
+
+ addr = vm_map_min(map);
+ result = vm_map_find(map, NULL, (vm_offset_t) 0,
+ &addr, size, TRUE);
+
+ lock_clear_recursive(&map->lock);
+ if (result != KERN_SUCCESS) {
+
+ if ( (vm_map_max(map) - vm_map_min(map)) < size ) {
+ vm_map_unlock(map);
+ return(0);
+ }
+
+ assert_wait((int)map, TRUE);
+ vm_map_unlock(map);
+thread_wakeup(&vm_pages_needed); /* XXX */
+ thread_block();
+ }
+ else {
+ vm_map_unlock(map);
+ }
+
+ } while (result != KERN_SUCCESS);
+
+ return(addr);
+}
+
+/*
+ * kmem_alloc_wired_wait
+ *
+ * Allocates nonpageable memory from a sub-map of the kernel. If the submap
+ * has no room, the caller sleeps waiting for more memory in the submap.
+ *
+ */
+vm_offset_t kmem_alloc_wired_wait(map, size)
+ vm_map_t map;
+ vm_size_t size;
+{
+ vm_offset_t addr;
+ int result;
+
+ size = round_page(size);
+
+ do {
+ /*
+ * To make this work for more than one map,
+ * use the map's lock to lock out sleepers/wakers.
+ * Unfortunately, vm_map_find also grabs the map lock.
+ */
+ vm_map_lock(map);
+ lock_set_recursive(&map->lock);
+
+ addr = vm_map_min(map);
+ result = vm_map_find(map, NULL, (vm_offset_t) 0,
+ &addr, size, FALSE);
+
+ lock_clear_recursive(&map->lock);
+ if (result != KERN_SUCCESS) {
+
+ if ( (vm_map_max(map) - vm_map_min(map)) < size ) {
+ vm_map_unlock(map);
+ return(0);
+ }
+
+ assert_wait((int)map, TRUE);
+ vm_map_unlock(map);
+thread_wakeup(&vm_pages_needed); /* XXX */
+ thread_block();
+ }
+ else {
+ vm_map_unlock(map);
+ }
+
+ } while (result != KERN_SUCCESS);
+
+ return(addr);
+}
+
+/*
+ * kmem_free_wakeup
+ *
+ * Returns memory to a submap of the kernel, and wakes up any threads
+ * waiting for memory in that map.
+ */
+void kmem_free_wakeup(map, addr, size)
+ vm_map_t map;
+ vm_offset_t addr;
+ vm_size_t size;
+{
+ vm_map_lock(map);
+ (void) vm_map_delete(map, trunc_page(addr), round_page(addr + size));
+ thread_wakeup((int)map);
+ vm_map_unlock(map);
+}
+
+/*
+ * kmem_init:
+ *
+ * Initialize the kernel's virtual memory map, taking
+ * into account all memory allocated up to this time.
+ */
+void kmem_init(start, end)
+ vm_offset_t start;
+ vm_offset_t end;
+{
+ vm_offset_t addr;
+ extern vm_map_t kernel_map;
+
+ addr = VM_MIN_KERNEL_ADDRESS;
+ kernel_map = vm_map_create(pmap_kernel(), addr, end, FALSE);
+ (void) vm_map_find(kernel_map, NULL, (vm_offset_t) 0,
+ &addr, (start - VM_MIN_KERNEL_ADDRESS),
+ FALSE);
+}
projects / unix-history / commitdiff