/*-
* 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.
* 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.
*
* from: @(#)vm_kern.c 8.3 (Berkeley) 1/12/94
*
*
* 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/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h> /* for ticks and hz */
#include <sys/eventhandler.h>
#include <sys/lock.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/rwlock.h>
#include <sys/sysctl.h>
#include <sys/vmem.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_kern.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pageout.h>
#include <vm/vm_extern.h>
#include <vm/uma.h>
vm_map_t kernel_map;
vm_map_t exec_map;
vm_map_t pipe_map;
const void *zero_region;
CTASSERT((ZERO_REGION_SIZE & PAGE_MASK) == 0);
SYSCTL_ULONG(_vm, OID_AUTO, min_kernel_address, CTLFLAG_RD,
NULL, VM_MIN_KERNEL_ADDRESS, "Min kernel address");
SYSCTL_ULONG(_vm, OID_AUTO, max_kernel_address, CTLFLAG_RD,
#if defined(__arm__) || defined(__sparc64__)
&vm_max_kernel_address, 0,
#else
NULL, VM_MAX_KERNEL_ADDRESS,
#endif
"Max kernel address");
/*
* kva_alloc:
*
* Allocate a virtual address range with no underlying object and
* no initial mapping to physical memory. Any mapping from this
* range to physical memory must be explicitly created prior to
* its use, typically with pmap_qenter(). Any attempt to create
* a mapping on demand through vm_fault() will result in a panic.
*/
vm_offset_t
kva_alloc(size)
vm_size_t size;
{
vm_offset_t addr;
size = round_page(size);
if (vmem_alloc(kernel_arena, size, M_BESTFIT | M_NOWAIT, &addr))
return (0);
return (addr);
}
/*
* kva_free:
*
* Release a region of kernel virtual memory allocated
* with kva_alloc, and return the physical pages
* associated with that region.
*
* This routine may not block on kernel maps.
*/
void
kva_free(addr, size)
vm_offset_t addr;
vm_size_t size;
{
size = round_page(size);
vmem_free(kernel_arena, addr, size);
}
/*
* Allocates a region from the kernel address map and physical pages
* within the specified address range to the kernel object. Creates a
* wired mapping from this region to these pages, and returns the
* region's starting virtual address. The allocated pages are not
* necessarily physically contiguous. If M_ZERO is specified through the
* given flags, then the pages are zeroed before they are mapped.
*/
vm_offset_t
kmem_alloc_attr(vmem_t *vmem, vm_size_t size, int flags, vm_paddr_t low,
vm_paddr_t high, vm_memattr_t memattr)
{
vm_object_t object = vmem == kmem_arena ? kmem_object : kernel_object;
vm_offset_t addr;
vm_ooffset_t offset;
vm_page_t m;
int pflags, tries;
int i;
size = round_page(size);
if (vmem_alloc(vmem, size, M_BESTFIT | flags, &addr))
return (0);
offset = addr - VM_MIN_KERNEL_ADDRESS;
pflags = malloc2vm_flags(flags) | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED;
VM_OBJECT_WLOCK(object);
for (i = 0; i < size; i += PAGE_SIZE) {
tries = 0;
retry:
m = vm_page_alloc_contig(object, OFF_TO_IDX(offset + i),
pflags, 1, low, high, PAGE_SIZE, 0, memattr);
if (m == NULL) {
VM_OBJECT_WUNLOCK(object);
if (tries < ((flags & M_NOWAIT) != 0 ? 1 : 3)) {
vm_pageout_grow_cache(tries, low, high);
VM_OBJECT_WLOCK(object);
tries++;
goto retry;
}
/*
* Unmap and free the pages.
*/
if (i != 0)
pmap_remove(kernel_pmap, addr, addr + i);
while (i != 0) {
i -= PAGE_SIZE;
m = vm_page_lookup(object,
OFF_TO_IDX(offset + i));
vm_page_unwire(m, PQ_INACTIVE);
vm_page_free(m);
}
vmem_free(vmem, addr, size);
return (0);
}
if ((flags & M_ZERO) && (m->flags & PG_ZERO) == 0)
pmap_zero_page(m);
m->valid = VM_PAGE_BITS_ALL;
pmap_enter(kernel_pmap, addr + i, m, VM_PROT_ALL,
VM_PROT_ALL | PMAP_ENTER_WIRED, 0);
}
VM_OBJECT_WUNLOCK(object);
return (addr);
}
/*
* Allocates a region from the kernel address map and physically
* contiguous pages within the specified address range to the kernel
* object. Creates a wired mapping from this region to these pages, and
* returns the region's starting virtual address. If M_ZERO is specified
* through the given flags, then the pages are zeroed before they are
* mapped.
*/
vm_offset_t
kmem_alloc_contig(struct vmem *vmem, vm_size_t size, int flags, vm_paddr_t low,
vm_paddr_t high, u_long alignment, vm_paddr_t boundary,
vm_memattr_t memattr)
{
vm_object_t object = vmem == kmem_arena ? kmem_object : kernel_object;
vm_offset_t addr, tmp;
vm_ooffset_t offset;
vm_page_t end_m, m;
int pflags, tries;
size = round_page(size);
if (vmem_alloc(vmem, size, flags | M_BESTFIT, &addr))
return (0);
offset = addr - VM_MIN_KERNEL_ADDRESS;
pflags = malloc2vm_flags(flags) | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED;
VM_OBJECT_WLOCK(object);
tries = 0;
retry:
m = vm_page_alloc_contig(object, OFF_TO_IDX(offset), pflags,
atop(size), low, high, alignment, boundary, memattr);
if (m == NULL) {
VM_OBJECT_WUNLOCK(object);
if (tries < ((flags & M_NOWAIT) != 0 ? 1 : 3)) {
vm_pageout_grow_cache(tries, low, high);
VM_OBJECT_WLOCK(object);
tries++;
goto retry;
}
vmem_free(vmem, addr, size);
return (0);
}
end_m = m + atop(size);
tmp = addr;
for (; m < end_m; m++) {
if ((flags & M_ZERO) && (m->flags & PG_ZERO) == 0)
pmap_zero_page(m);
m->valid = VM_PAGE_BITS_ALL;
pmap_enter(kernel_pmap, tmp, m, VM_PROT_ALL,
VM_PROT_ALL | PMAP_ENTER_WIRED, 0);
tmp += PAGE_SIZE;
}
VM_OBJECT_WUNLOCK(object);
return (addr);
}
/*
* 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
* min, max Returned endpoints of map
* size Size of range to find
* superpage_align Request that min is superpage aligned
*/
vm_map_t
kmem_suballoc(vm_map_t parent, vm_offset_t *min, vm_offset_t *max,
vm_size_t size, boolean_t superpage_align)
{
int ret;
vm_map_t result;
size = round_page(size);
*min = vm_map_min(parent);
ret = vm_map_find(parent, NULL, 0, min, size, 0, superpage_align ?
VMFS_SUPER_SPACE : VMFS_ANY_SPACE, VM_PROT_ALL, VM_PROT_ALL,
MAP_ACC_NO_CHARGE);
if (ret != KERN_SUCCESS)
panic("kmem_suballoc: bad status return of %d", ret);
*max = *min + size;
result = vm_map_create(vm_map_pmap(parent), *min, *max);
if (result == NULL)
panic("kmem_suballoc: cannot create submap");
if (vm_map_submap(parent, *min, *max, result) != KERN_SUCCESS)
panic("kmem_suballoc: unable to change range to submap");
return (result);
}
/*
* kmem_malloc:
*
* Allocate wired-down pages in the kernel's address space.
*/
vm_offset_t
kmem_malloc(struct vmem *vmem, vm_size_t size, int flags)
{
vm_offset_t addr;
int rv;
size = round_page(size);
if (vmem_alloc(vmem, size, flags | M_BESTFIT, &addr))
return (0);
rv = kmem_back((vmem == kmem_arena) ? kmem_object : kernel_object,
addr, size, flags);
if (rv != KERN_SUCCESS) {
vmem_free(vmem, addr, size);
return (0);
}
return (addr);
}
/*
* kmem_back:
*
* Allocate physical pages for the specified virtual address range.
*/
int
kmem_back(vm_object_t object, vm_offset_t addr, vm_size_t size, int flags)
{
vm_offset_t offset, i;
vm_page_t m;
int pflags;
KASSERT(object == kmem_object || object == kernel_object,
("kmem_back: only supports kernel objects."));
offset = addr - VM_MIN_KERNEL_ADDRESS;
pflags = malloc2vm_flags(flags) | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED;
VM_OBJECT_WLOCK(object);
for (i = 0; i < size; i += PAGE_SIZE) {
retry:
m = vm_page_alloc(object, OFF_TO_IDX(offset + i), pflags);
/*
* 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) {
if ((flags & M_NOWAIT) == 0) {
VM_OBJECT_WUNLOCK(object);
VM_WAIT;
VM_OBJECT_WLOCK(object);
goto retry;
}
/*
* Unmap and free the pages.
*/
if (i != 0)
pmap_remove(kernel_pmap, addr, addr + i);
while (i != 0) {
i -= PAGE_SIZE;
m = vm_page_lookup(object,
OFF_TO_IDX(offset + i));
vm_page_unwire(m, PQ_INACTIVE);
vm_page_free(m);
}
VM_OBJECT_WUNLOCK(object);
return (KERN_NO_SPACE);
}
if (flags & M_ZERO && (m->flags & PG_ZERO) == 0)
pmap_zero_page(m);
KASSERT((m->oflags & VPO_UNMANAGED) != 0,
("kmem_malloc: page %p is managed", m));
m->valid = VM_PAGE_BITS_ALL;
pmap_enter(kernel_pmap, addr + i, m, VM_PROT_ALL,
VM_PROT_ALL | PMAP_ENTER_WIRED, 0);
}
VM_OBJECT_WUNLOCK(object);
return (KERN_SUCCESS);
}
void
kmem_unback(vm_object_t object, vm_offset_t addr, vm_size_t size)
{
vm_page_t m;
vm_offset_t offset;
int i;
KASSERT(object == kmem_object || object == kernel_object,
("kmem_unback: only supports kernel objects."));
pmap_remove(kernel_pmap, addr, addr + size);
offset = addr - VM_MIN_KERNEL_ADDRESS;
VM_OBJECT_WLOCK(object);
for (i = 0; i < size; i += PAGE_SIZE) {
m = vm_page_lookup(object, OFF_TO_IDX(offset + i));
vm_page_unwire(m, PQ_INACTIVE);
vm_page_free(m);
}
VM_OBJECT_WUNLOCK(object);
}
/*
* kmem_free:
*
* Free memory allocated with kmem_malloc. The size must match the
* original allocation.
*/
void
kmem_free(struct vmem *vmem, vm_offset_t addr, vm_size_t size)
{
size = round_page(size);
kmem_unback((vmem == kmem_arena) ? kmem_object : kernel_object,
addr, size);
vmem_free(vmem, addr, size);
}
/*
* kmap_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.
*
* This routine may block.
*/
vm_offset_t
kmap_alloc_wait(map, size)
vm_map_t map;
vm_size_t size;
{
vm_offset_t addr;
size = round_page(size);
if (!swap_reserve(size))
return (0);
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, vm_map_min(map), 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);
swap_release(size);
return (0);
}
map->needs_wakeup = TRUE;
vm_map_unlock_and_wait(map, 0);
}
vm_map_insert(map, NULL, 0, addr, addr + size, VM_PROT_ALL,
VM_PROT_ALL, MAP_ACC_CHARGED);
vm_map_unlock(map);
return (addr);
}
/*
* kmap_free_wakeup:
*
* Returns memory to a submap of the kernel, and wakes up any processes
* waiting for memory in that map.
*/
void
kmap_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));
if (map->needs_wakeup) {
map->needs_wakeup = FALSE;
vm_map_wakeup(map);
}
vm_map_unlock(map);
}
void
kmem_init_zero_region(void)
{
vm_offset_t addr, i;
vm_page_t m;
/*
* Map a single physical page of zeros to a larger virtual range.
* This requires less looping in places that want large amounts of
* zeros, while not using much more physical resources.
*/
addr = kva_alloc(ZERO_REGION_SIZE);
m = vm_page_alloc(NULL, 0, VM_ALLOC_NORMAL |
VM_ALLOC_NOOBJ | VM_ALLOC_WIRED | VM_ALLOC_ZERO);
if ((m->flags & PG_ZERO) == 0)
pmap_zero_page(m);
for (i = 0; i < ZERO_REGION_SIZE; i += PAGE_SIZE)
pmap_qenter(addr + i, &m, 1);
pmap_protect(kernel_pmap, addr, addr + ZERO_REGION_SIZE, VM_PROT_READ);
zero_region = (const void *)addr;
}
/*
* kmem_init:
*
* 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;
{
vm_map_t m;
m = vm_map_create(kernel_pmap, VM_MIN_KERNEL_ADDRESS, end);
m->system_map = 1;
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_ooffset_t) 0,
#ifdef __amd64__
KERNBASE,
#else
VM_MIN_KERNEL_ADDRESS,
#endif
start, VM_PROT_ALL, VM_PROT_ALL, MAP_NOFAULT);
/* ... and ending with the completion of the above `insert' */
vm_map_unlock(m);
}
#ifdef DIAGNOSTIC
/*
* Allow userspace to directly trigger the VM drain routine for testing
* purposes.
*/
static int
debug_vm_lowmem(SYSCTL_HANDLER_ARGS)
{
int error, i;
i = 0;
error = sysctl_handle_int(oidp, &i, 0, req);
if (error)
return (error);
if (i)
EVENTHANDLER_INVOKE(vm_lowmem, 0);
return (0);
}
SYSCTL_PROC(_debug, OID_AUTO, vm_lowmem, CTLTYPE_INT | CTLFLAG_RW, 0, 0,
debug_vm_lowmem, "I", "set to trigger vm_lowmem event");
#endif
