4.4BSD/usr/src/sys/vm/vm_kern.c
/*
* Copyright (c) 1991, 1993
* The 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 8.1 (Berkeley) 6/11/93
*
*
* 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 <sys/param.h>
#include <sys/systm.h>
#include <vm/vm.h>
#include <vm/vm_page.h>
#include <vm/vm_pageout.h>
#include <vm/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
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.
*/
/*
* Locate sufficient space in the map. This will give us the
* final virtual address for the new memory, and thus will tell
* us the offset within the kernel map.
*/
vm_map_lock(map);
if (vm_map_findspace(map, 0, size, &addr)) {
vm_map_unlock(map);
return (0);
}
offset = addr - VM_MIN_KERNEL_ADDRESS;
vm_object_reference(kernel_object);
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->flags &= ~PG_BUSY;
}
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)
panic("kern_malloc_alloc: map != {kmem,mb}_map");
size = round_page(size);
addr = vm_map_min(map);
/*
* Locate sufficient space in the map. This will give us the
* final virtual address for the new memory, and thus will tell
* us the offset within the kernel map.
*/
vm_map_lock(map);
if (vm_map_findspace(map, 0, size, &addr)) {
vm_map_unlock(map);
if (canwait) /* XXX should wait */
panic("kmem_malloc: %s too small",
map == kmem_map ? "kmem_map" : "mb_map");
return (0);
}
offset = addr - vm_map_min(kmem_map);
vm_object_reference(kmem_object);
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->flags &= ~PG_BUSY;
}
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);
for (;;) {
/*
* To make this work for more than one map,
* use the map's lock to lock out sleepers/wakers.
*/
vm_map_lock(map);
if (vm_map_findspace(map, 0, size, &addr) == 0)
break;
/* no space now; see if we can ever get space */
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_block();
}
vm_map_insert(map, NULL, (vm_offset_t)0, addr, addr + size);
vm_map_unlock(map);
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);
}
/*
* Create the kernel map; insert a mapping covering kernel text, data, bss,
* and all space allocated thus far (`boostrap' data). The new map will thus
* map the range between VM_MIN_KERNEL_ADDRESS and `start' as allocated, and
* the range between `start' and `end' as free.
*/
void kmem_init(start, end)
vm_offset_t start, end;
{
register vm_map_t m;
m = vm_map_create(kernel_pmap, VM_MIN_KERNEL_ADDRESS, end, FALSE);
vm_map_lock(m);
/* N.B.: cannot use kgdb to debug, starting with this assignment ... */
kernel_map = m;
(void) vm_map_insert(m, NULL, (vm_offset_t)0,
VM_MIN_KERNEL_ADDRESS, start);
/* ... and ending with the completion of the above `insert' */
vm_map_unlock(m);
}