freebsd-dev/sys/vm/vm_kern.c
Mark Johnston f822c9e287 Apply mapping protections to preloaded kernel modules on amd64.
With an upcoming change the amd64 kernel will map preloaded files RW
instead of RWX, so the kernel linker must adjust protections
appropriately using pmap_change_prot().

Reviewed by:	kib
MFC after:	1 month
Sponsored by:	Netflix
Differential Revision:	https://reviews.freebsd.org/D21860
2019-10-18 13:56:45 +00:00

884 lines
24 KiB
C

/*-
* SPDX-License-Identifier: (BSD-3-Clause AND MIT-CMU)
*
* 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. 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 "opt_vm.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h> /* for ticks and hz */
#include <sys/domainset.h>
#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 <sys/vmmeter.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_domainset.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_phys.h>
#include <vm/vm_pagequeue.h>
#include <vm/vm_radix.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);
/* NB: Used by kernel debuggers. */
const u_long vm_maxuser_address = VM_MAXUSER_ADDRESS;
u_int exec_map_entry_size;
u_int exec_map_entries;
SYSCTL_ULONG(_vm, OID_AUTO, min_kernel_address, CTLFLAG_RD,
SYSCTL_NULL_ULONG_PTR, 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
SYSCTL_NULL_ULONG_PTR, VM_MAX_KERNEL_ADDRESS,
#endif
"Max kernel address");
#if VM_NRESERVLEVEL > 0
#define KVA_QUANTUM_SHIFT (VM_LEVEL_0_ORDER + PAGE_SHIFT)
#else
/* On non-superpage architectures we want large import sizes. */
#define KVA_QUANTUM_SHIFT (8 + PAGE_SHIFT)
#endif
#define KVA_QUANTUM (1 << KVA_QUANTUM_SHIFT)
/*
* 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(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(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.
*/
static vm_offset_t
kmem_alloc_attr_domain(int domain, vm_size_t size, int flags, vm_paddr_t low,
vm_paddr_t high, vm_memattr_t memattr)
{
vmem_t *vmem;
vm_object_t object = kernel_object;
vm_offset_t addr, i, offset;
vm_page_t m;
int pflags, tries;
vm_prot_t prot;
size = round_page(size);
vmem = vm_dom[domain].vmd_kernel_arena;
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;
pflags &= ~(VM_ALLOC_NOWAIT | VM_ALLOC_WAITOK | VM_ALLOC_WAITFAIL);
pflags |= VM_ALLOC_NOWAIT;
prot = (flags & M_EXEC) != 0 ? VM_PROT_ALL : VM_PROT_RW;
VM_OBJECT_WLOCK(object);
for (i = 0; i < size; i += PAGE_SIZE) {
tries = 0;
retry:
m = vm_page_alloc_contig_domain(object, atop(offset + i),
domain, pflags, 1, low, high, PAGE_SIZE, 0, memattr);
if (m == NULL) {
VM_OBJECT_WUNLOCK(object);
if (tries < ((flags & M_NOWAIT) != 0 ? 1 : 3)) {
if (!vm_page_reclaim_contig_domain(domain,
pflags, 1, low, high, PAGE_SIZE, 0) &&
(flags & M_WAITOK) != 0)
vm_wait_domain(domain);
VM_OBJECT_WLOCK(object);
tries++;
goto retry;
}
kmem_unback(object, addr, i);
vmem_free(vmem, addr, size);
return (0);
}
KASSERT(vm_phys_domain(m) == domain,
("kmem_alloc_attr_domain: Domain mismatch %d != %d",
vm_phys_domain(m), domain));
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, prot,
prot | PMAP_ENTER_WIRED, 0);
}
VM_OBJECT_WUNLOCK(object);
return (addr);
}
vm_offset_t
kmem_alloc_attr(vm_size_t size, int flags, vm_paddr_t low, vm_paddr_t high,
vm_memattr_t memattr)
{
return (kmem_alloc_attr_domainset(DOMAINSET_RR(), size, flags, low,
high, memattr));
}
vm_offset_t
kmem_alloc_attr_domainset(struct domainset *ds, vm_size_t size, int flags,
vm_paddr_t low, vm_paddr_t high, vm_memattr_t memattr)
{
struct vm_domainset_iter di;
vm_offset_t addr;
int domain;
vm_domainset_iter_policy_init(&di, ds, &domain, &flags);
do {
addr = kmem_alloc_attr_domain(domain, size, flags, low, high,
memattr);
if (addr != 0)
break;
} while (vm_domainset_iter_policy(&di, &domain) == 0);
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.
*/
static vm_offset_t
kmem_alloc_contig_domain(int domain, 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)
{
vmem_t *vmem;
vm_object_t object = kernel_object;
vm_offset_t addr, offset, tmp;
vm_page_t end_m, m;
u_long npages;
int pflags, tries;
size = round_page(size);
vmem = vm_dom[domain].vmd_kernel_arena;
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;
pflags &= ~(VM_ALLOC_NOWAIT | VM_ALLOC_WAITOK | VM_ALLOC_WAITFAIL);
pflags |= VM_ALLOC_NOWAIT;
npages = atop(size);
VM_OBJECT_WLOCK(object);
tries = 0;
retry:
m = vm_page_alloc_contig_domain(object, atop(offset), domain, pflags,
npages, low, high, alignment, boundary, memattr);
if (m == NULL) {
VM_OBJECT_WUNLOCK(object);
if (tries < ((flags & M_NOWAIT) != 0 ? 1 : 3)) {
if (!vm_page_reclaim_contig_domain(domain, pflags,
npages, low, high, alignment, boundary) &&
(flags & M_WAITOK) != 0)
vm_wait_domain(domain);
VM_OBJECT_WLOCK(object);
tries++;
goto retry;
}
vmem_free(vmem, addr, size);
return (0);
}
KASSERT(vm_phys_domain(m) == domain,
("kmem_alloc_contig_domain: Domain mismatch %d != %d",
vm_phys_domain(m), domain));
end_m = m + npages;
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_RW,
VM_PROT_RW | PMAP_ENTER_WIRED, 0);
tmp += PAGE_SIZE;
}
VM_OBJECT_WUNLOCK(object);
return (addr);
}
vm_offset_t
kmem_alloc_contig(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)
{
return (kmem_alloc_contig_domainset(DOMAINSET_RR(), size, flags, low,
high, alignment, boundary, memattr));
}
vm_offset_t
kmem_alloc_contig_domainset(struct domainset *ds, 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)
{
struct vm_domainset_iter di;
vm_offset_t addr;
int domain;
vm_domainset_iter_policy_init(&di, ds, &domain, &flags);
do {
addr = kmem_alloc_contig_domain(domain, size, flags, low, high,
alignment, boundary, memattr);
if (addr != 0)
break;
} while (vm_domainset_iter_policy(&di, &domain) == 0);
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_domain:
*
* Allocate wired-down pages in the kernel's address space.
*/
static vm_offset_t
kmem_malloc_domain(int domain, vm_size_t size, int flags)
{
vmem_t *arena;
vm_offset_t addr;
int rv;
#if VM_NRESERVLEVEL > 0
if (__predict_true((flags & M_EXEC) == 0))
arena = vm_dom[domain].vmd_kernel_arena;
else
arena = vm_dom[domain].vmd_kernel_rwx_arena;
#else
arena = vm_dom[domain].vmd_kernel_arena;
#endif
size = round_page(size);
if (vmem_alloc(arena, size, flags | M_BESTFIT, &addr))
return (0);
rv = kmem_back_domain(domain, kernel_object, addr, size, flags);
if (rv != KERN_SUCCESS) {
vmem_free(arena, addr, size);
return (0);
}
return (addr);
}
vm_offset_t
kmem_malloc(vm_size_t size, int flags)
{
return (kmem_malloc_domainset(DOMAINSET_RR(), size, flags));
}
vm_offset_t
kmem_malloc_domainset(struct domainset *ds, vm_size_t size, int flags)
{
struct vm_domainset_iter di;
vm_offset_t addr;
int domain;
vm_domainset_iter_policy_init(&di, ds, &domain, &flags);
do {
addr = kmem_malloc_domain(domain, size, flags);
if (addr != 0)
break;
} while (vm_domainset_iter_policy(&di, &domain) == 0);
return (addr);
}
/*
* kmem_back_domain:
*
* Allocate physical pages from the specified domain for the specified
* virtual address range.
*/
int
kmem_back_domain(int domain, vm_object_t object, vm_offset_t addr,
vm_size_t size, int flags)
{
vm_offset_t offset, i;
vm_page_t m, mpred;
vm_prot_t prot;
int pflags;
KASSERT(object == kernel_object,
("kmem_back_domain: only supports kernel object."));
offset = addr - VM_MIN_KERNEL_ADDRESS;
pflags = malloc2vm_flags(flags) | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED;
pflags &= ~(VM_ALLOC_NOWAIT | VM_ALLOC_WAITOK | VM_ALLOC_WAITFAIL);
if (flags & M_WAITOK)
pflags |= VM_ALLOC_WAITFAIL;
prot = (flags & M_EXEC) != 0 ? VM_PROT_ALL : VM_PROT_RW;
i = 0;
VM_OBJECT_WLOCK(object);
retry:
mpred = vm_radix_lookup_le(&object->rtree, atop(offset + i));
for (; i < size; i += PAGE_SIZE, mpred = m) {
m = vm_page_alloc_domain_after(object, atop(offset + i),
domain, pflags, mpred);
/*
* 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)
goto retry;
VM_OBJECT_WUNLOCK(object);
kmem_unback(object, addr, i);
return (KERN_NO_SPACE);
}
KASSERT(vm_phys_domain(m) == domain,
("kmem_back_domain: Domain mismatch %d != %d",
vm_phys_domain(m), domain));
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, prot,
prot | PMAP_ENTER_WIRED, 0);
#if VM_NRESERVLEVEL > 0
if (__predict_false((prot & VM_PROT_EXECUTE) != 0))
m->oflags |= VPO_KMEM_EXEC;
#endif
}
VM_OBJECT_WUNLOCK(object);
return (KERN_SUCCESS);
}
/*
* 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 end, next, start;
int domain, rv;
KASSERT(object == kernel_object,
("kmem_back: only supports kernel object."));
for (start = addr, end = addr + size; addr < end; addr = next) {
/*
* We must ensure that pages backing a given large virtual page
* all come from the same physical domain.
*/
if (vm_ndomains > 1) {
domain = (addr >> KVA_QUANTUM_SHIFT) % vm_ndomains;
while (VM_DOMAIN_EMPTY(domain))
domain++;
next = roundup2(addr + 1, KVA_QUANTUM);
if (next > end || next < start)
next = end;
} else {
domain = 0;
next = end;
}
rv = kmem_back_domain(domain, object, addr, next - addr, flags);
if (rv != KERN_SUCCESS) {
kmem_unback(object, start, addr - start);
break;
}
}
return (rv);
}
/*
* kmem_unback:
*
* Unmap and free the physical pages underlying the specified virtual
* address range.
*
* A physical page must exist within the specified object at each index
* that is being unmapped.
*/
static struct vmem *
_kmem_unback(vm_object_t object, vm_offset_t addr, vm_size_t size)
{
struct vmem *arena;
vm_page_t m, next;
vm_offset_t end, offset;
int domain;
KASSERT(object == kernel_object,
("kmem_unback: only supports kernel object."));
if (size == 0)
return (NULL);
pmap_remove(kernel_pmap, addr, addr + size);
offset = addr - VM_MIN_KERNEL_ADDRESS;
end = offset + size;
VM_OBJECT_WLOCK(object);
m = vm_page_lookup(object, atop(offset));
domain = vm_phys_domain(m);
#if VM_NRESERVLEVEL > 0
if (__predict_true((m->oflags & VPO_KMEM_EXEC) == 0))
arena = vm_dom[domain].vmd_kernel_arena;
else
arena = vm_dom[domain].vmd_kernel_rwx_arena;
#else
arena = vm_dom[domain].vmd_kernel_arena;
#endif
for (; offset < end; offset += PAGE_SIZE, m = next) {
next = vm_page_next(m);
vm_page_unwire_noq(m);
vm_page_free(m);
}
VM_OBJECT_WUNLOCK(object);
return (arena);
}
void
kmem_unback(vm_object_t object, vm_offset_t addr, vm_size_t size)
{
(void)_kmem_unback(object, addr, size);
}
/*
* kmem_free:
*
* Free memory allocated with kmem_malloc. The size must match the
* original allocation.
*/
void
kmem_free(vm_offset_t addr, vm_size_t size)
{
struct vmem *arena;
size = round_page(size);
arena = _kmem_unback(kernel_object, addr, size);
if (arena != NULL)
vmem_free(arena, 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(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);
addr = vm_map_findspace(map, vm_map_min(map), size);
if (addr + size <= vm_map_max(map))
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_RW, VM_PROT_RW,
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(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;
}
/*
* Import KVA from the kernel map into the kernel arena.
*/
static int
kva_import(void *unused, vmem_size_t size, int flags, vmem_addr_t *addrp)
{
vm_offset_t addr;
int result;
KASSERT((size % KVA_QUANTUM) == 0,
("kva_import: Size %jd is not a multiple of %d",
(intmax_t)size, (int)KVA_QUANTUM));
addr = vm_map_min(kernel_map);
result = vm_map_find(kernel_map, NULL, 0, &addr, size, 0,
VMFS_SUPER_SPACE, VM_PROT_ALL, VM_PROT_ALL, MAP_NOFAULT);
if (result != KERN_SUCCESS)
return (ENOMEM);
*addrp = addr;
return (0);
}
/*
* Import KVA from a parent arena into a per-domain arena. Imports must be
* KVA_QUANTUM-aligned and a multiple of KVA_QUANTUM in size.
*/
static int
kva_import_domain(void *arena, vmem_size_t size, int flags, vmem_addr_t *addrp)
{
KASSERT((size % KVA_QUANTUM) == 0,
("kva_import_domain: Size %jd is not a multiple of %d",
(intmax_t)size, (int)KVA_QUANTUM));
return (vmem_xalloc(arena, size, KVA_QUANTUM, 0, 0, VMEM_ADDR_MIN,
VMEM_ADDR_MAX, flags, addrp));
}
/*
* 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.
* Create the kernel vmem arena and its per-domain children.
*/
void
kmem_init(vm_offset_t start, vm_offset_t end)
{
vm_map_t m;
int domain;
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, 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' */
#ifdef __amd64__
/*
* Mark KVA used for the page array as allocated. Other platforms
* that handle vm_page_array allocation can simply adjust virtual_avail
* instead.
*/
(void)vm_map_insert(m, NULL, 0, (vm_offset_t)vm_page_array,
(vm_offset_t)vm_page_array + round_2mpage(vm_page_array_size *
sizeof(struct vm_page)),
VM_PROT_RW, VM_PROT_RW, MAP_NOFAULT);
#endif
vm_map_unlock(m);
/*
* Initialize the kernel_arena. This can grow on demand.
*/
vmem_init(kernel_arena, "kernel arena", 0, 0, PAGE_SIZE, 0, 0);
vmem_set_import(kernel_arena, kva_import, NULL, NULL, KVA_QUANTUM);
for (domain = 0; domain < vm_ndomains; domain++) {
/*
* Initialize the per-domain arenas. These are used to color
* the KVA space in a way that ensures that virtual large pages
* are backed by memory from the same physical domain,
* maximizing the potential for superpage promotion.
*/
vm_dom[domain].vmd_kernel_arena = vmem_create(
"kernel arena domain", 0, 0, PAGE_SIZE, 0, M_WAITOK);
vmem_set_import(vm_dom[domain].vmd_kernel_arena,
kva_import_domain, NULL, kernel_arena, KVA_QUANTUM);
/*
* In architectures with superpages, maintain separate arenas
* for allocations with permissions that differ from the
* "standard" read/write permissions used for kernel memory,
* so as not to inhibit superpage promotion.
*/
#if VM_NRESERVLEVEL > 0
vm_dom[domain].vmd_kernel_rwx_arena = vmem_create(
"kernel rwx arena domain", 0, 0, PAGE_SIZE, 0, M_WAITOK);
vmem_set_import(vm_dom[domain].vmd_kernel_rwx_arena,
kva_import_domain, (vmem_release_t *)vmem_xfree,
kernel_arena, KVA_QUANTUM);
#endif
}
}
/*
* kmem_bootstrap_free:
*
* Free pages backing preloaded data (e.g., kernel modules) to the
* system. Currently only supported on platforms that create a
* vm_phys segment for preloaded data.
*/
void
kmem_bootstrap_free(vm_offset_t start, vm_size_t size)
{
#if defined(__i386__) || defined(__amd64__)
struct vm_domain *vmd;
vm_offset_t end, va;
vm_paddr_t pa;
vm_page_t m;
end = trunc_page(start + size);
start = round_page(start);
#ifdef __amd64__
/*
* Preloaded files do not have execute permissions by default on amd64.
* Restore the default permissions to ensure that the direct map alias
* is updated.
*/
pmap_change_prot(start, end - start, VM_PROT_RW);
#endif
for (va = start; va < end; va += PAGE_SIZE) {
pa = pmap_kextract(va);
m = PHYS_TO_VM_PAGE(pa);
vmd = vm_pagequeue_domain(m);
vm_domain_free_lock(vmd);
vm_phys_free_pages(m, 0);
vm_domain_free_unlock(vmd);
vm_domain_freecnt_inc(vmd, 1);
vm_cnt.v_page_count++;
}
pmap_remove(kernel_pmap, start, end);
(void)vmem_add(kernel_arena, start, end - start, M_WAITOK);
#endif
}
/*
* 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 & ~(VM_LOW_KMEM | VM_LOW_PAGES)) != 0)
return (EINVAL);
if (i != 0)
EVENTHANDLER_INVOKE(vm_lowmem, i);
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 with given flags");