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7818c2d37c
freebsd/sys/vm/vm_map.c
Alan Cox 268f19aacc vm: Reduce address space fragmentation 
jemalloc performs two types of virtual memory allocations: (1) large
chunks of virtual memory, where the chunk size is a multiple of a
superpage and explicitly aligned, and (2) small allocations, mostly
128KB, where no alignment is requested.  Typically, it starts with a
small allocation, and over time it makes both types of allocation.

With anon_loc being updated on every allocation, we wind up with a
repeating pattern of a small allocation, a large gap, and a large,
aligned allocation.  (As an aside, we wind up allocating a reservation
for these small allocations, but it will never fill because the next
large, aligned allocation updates anon_loc, leaving a gap that will
never be filled with other small allocations.)

With this change, anon_loc isn't updated on every allocation.  So, the
small allocations will be clustered together, the large allocations will
be clustered together, and there will be fewer gaps between the
anonymous memory allocations.  In addition, I see a small reduction in
reservations allocated (e.g., 1.6% during buildworld), fewer partially
populated reservations, and a small increase in 64KB page promotions on
arm64.

Reviewed by:	kib
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D39845
2024-06-13 15:13:45 -05:00

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/*-
* 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.
*
*
* 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.
*/
/*
* Virtual memory mapping module.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/elf.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/vmmeter.h>
#include <sys/mman.h>
#include <sys/vnode.h>
#include <sys/racct.h>
#include <sys/resourcevar.h>
#include <sys/rwlock.h>
#include <sys/file.h>
#include <sys/sysctl.h>
#include <sys/sysent.h>
#include <sys/shm.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_page.h>
#include <vm/vm_pageout.h>
#include <vm/vm_object.h>
#include <vm/vm_pager.h>
#include <vm/vm_kern.h>
#include <vm/vm_extern.h>
#include <vm/vnode_pager.h>
#include <vm/swap_pager.h>
#include <vm/uma.h>
/*
* Virtual memory maps provide for the mapping, protection,
* and sharing of virtual memory objects. In addition,
* this module provides for an efficient virtual copy of
* memory from one map to another.
*
* Synchronization is required prior to most operations.
*
* Maps consist of an ordered doubly-linked list of simple
* entries; a self-adjusting binary search tree of these
* entries is used to speed up lookups.
*
* Since portions of maps are specified by start/end addresses,
* which may not align with existing map entries, all
* routines merely "clip" entries to these start/end values.
* [That is, an entry is split into two, bordering at a
* start or end value.] Note that these clippings may not
* always be necessary (as the two resulting entries are then
* not changed); however, the clipping is done for convenience.
*
* As mentioned above, virtual copy operations are performed
* by copying VM object references from one map to
* another, and then marking both regions as copy-on-write.
*/
static struct mtx map_sleep_mtx;
static uma_zone_t mapentzone;
static uma_zone_t kmapentzone;
static uma_zone_t vmspace_zone;
static int vmspace_zinit(void *mem, int size, int flags);
static void _vm_map_init(vm_map_t map, pmap_t pmap, vm_offset_t min,
vm_offset_t max);
static void vm_map_entry_deallocate(vm_map_entry_t entry, boolean_t system_map);
static void vm_map_entry_dispose(vm_map_t map, vm_map_entry_t entry);
static void vm_map_entry_unwire(vm_map_t map, vm_map_entry_t entry);
static int vm_map_growstack(vm_map_t map, vm_offset_t addr,
vm_map_entry_t gap_entry);
static void vm_map_pmap_enter(vm_map_t map, vm_offset_t addr, vm_prot_t prot,
vm_object_t object, vm_pindex_t pindex, vm_size_t size, int flags);
#ifdef INVARIANTS
static void vmspace_zdtor(void *mem, int size, void *arg);
#endif
static int vm_map_stack_locked(vm_map_t map, vm_offset_t addrbos,
vm_size_t max_ssize, vm_size_t growsize, vm_prot_t prot, vm_prot_t max,
int cow);
static void vm_map_wire_entry_failure(vm_map_t map, vm_map_entry_t entry,
vm_offset_t failed_addr);
#define CONTAINS_BITS(set, bits) ((~(set) & (bits)) == 0)
#define ENTRY_CHARGED(e) ((e)->cred != NULL || \
((e)->object.vm_object != NULL && (e)->object.vm_object->cred != NULL && \
!((e)->eflags & MAP_ENTRY_NEEDS_COPY)))
/*
* PROC_VMSPACE_{UN,}LOCK() can be a noop as long as vmspaces are type
* stable.
*/
#define PROC_VMSPACE_LOCK(p) do { } while (0)
#define PROC_VMSPACE_UNLOCK(p) do { } while (0)
/*
* VM_MAP_RANGE_CHECK: [ internal use only ]
*
* Asserts that the starting and ending region
* addresses fall within the valid range of the map.
*/
#define VM_MAP_RANGE_CHECK(map, start, end) \
{ \
if (start < vm_map_min(map)) \
start = vm_map_min(map); \
if (end > vm_map_max(map)) \
end = vm_map_max(map); \
if (start > end) \
start = end; \
}
#ifndef UMA_USE_DMAP
/*
* Allocate a new slab for kernel map entries. The kernel map may be locked or
* unlocked, depending on whether the request is coming from the kernel map or a
* submap. This function allocates a virtual address range directly from the
* kernel map instead of the kmem_* layer to avoid recursion on the kernel map
* lock and also to avoid triggering allocator recursion in the vmem boundary
* tag allocator.
*/
static void *
kmapent_alloc(uma_zone_t zone, vm_size_t bytes, int domain, uint8_t *pflag,
int wait)
{
vm_offset_t addr;
int error, locked;
*pflag = UMA_SLAB_PRIV;
if (!(locked = vm_map_locked(kernel_map)))
vm_map_lock(kernel_map);
addr = vm_map_findspace(kernel_map, vm_map_min(kernel_map), bytes);
if (addr + bytes < addr || addr + bytes > vm_map_max(kernel_map))
panic("%s: kernel map is exhausted", __func__);
error = vm_map_insert(kernel_map, NULL, 0, addr, addr + bytes,
VM_PROT_RW, VM_PROT_RW, MAP_NOFAULT);
if (error != KERN_SUCCESS)
panic("%s: vm_map_insert() failed: %d", __func__, error);
if (!locked)
vm_map_unlock(kernel_map);
error = kmem_back_domain(domain, kernel_object, addr, bytes, M_NOWAIT |
M_USE_RESERVE | (wait & M_ZERO));
if (error == KERN_SUCCESS) {
return ((void *)addr);
} else {
if (!locked)
vm_map_lock(kernel_map);
vm_map_delete(kernel_map, addr, bytes);
if (!locked)
vm_map_unlock(kernel_map);
return (NULL);
}
}
static void
kmapent_free(void *item, vm_size_t size, uint8_t pflag)
{
vm_offset_t addr;
int error __diagused;
if ((pflag & UMA_SLAB_PRIV) == 0)
/* XXX leaked */
return;
addr = (vm_offset_t)item;
kmem_unback(kernel_object, addr, size);
error = vm_map_remove(kernel_map, addr, addr + size);
KASSERT(error == KERN_SUCCESS,
("%s: vm_map_remove failed: %d", __func__, error));
}
/*
* The worst-case upper bound on the number of kernel map entries that may be
* created before the zone must be replenished in _vm_map_unlock().
*/
#define KMAPENT_RESERVE 1
#endif /* !UMD_MD_SMALL_ALLOC */
/*
* vm_map_startup:
*
* Initialize the vm_map module. Must be called before any other vm_map
* routines.
*
* User map and entry structures are allocated from the general purpose
* memory pool. Kernel maps are statically defined. Kernel map entries
* require special handling to avoid recursion; see the comments above
* kmapent_alloc() and in vm_map_entry_create().
*/
void
vm_map_startup(void)
{
mtx_init(&map_sleep_mtx, "vm map sleep mutex", NULL, MTX_DEF);
/*
* Disable the use of per-CPU buckets: map entry allocation is
* serialized by the kernel map lock.
*/
kmapentzone = uma_zcreate("KMAP ENTRY", sizeof(struct vm_map_entry),
NULL, NULL, NULL, NULL, UMA_ALIGN_PTR,
UMA_ZONE_VM | UMA_ZONE_NOBUCKET);
#ifndef UMA_USE_DMAP
/* Reserve an extra map entry for use when replenishing the reserve. */
uma_zone_reserve(kmapentzone, KMAPENT_RESERVE + 1);
uma_prealloc(kmapentzone, KMAPENT_RESERVE + 1);
uma_zone_set_allocf(kmapentzone, kmapent_alloc);
uma_zone_set_freef(kmapentzone, kmapent_free);
#endif
mapentzone = uma_zcreate("MAP ENTRY", sizeof(struct vm_map_entry),
NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
vmspace_zone = uma_zcreate("VMSPACE", sizeof(struct vmspace), NULL,
#ifdef INVARIANTS
vmspace_zdtor,
#else
NULL,
#endif
vmspace_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
}
static int
vmspace_zinit(void *mem, int size, int flags)
{
struct vmspace *vm;
vm_map_t map;
vm = (struct vmspace *)mem;
map = &vm->vm_map;
memset(map, 0, sizeof(*map));
mtx_init(&map->system_mtx, "vm map (system)", NULL,
MTX_DEF | MTX_DUPOK);
sx_init(&map->lock, "vm map (user)");
PMAP_LOCK_INIT(vmspace_pmap(vm));
return (0);
}
#ifdef INVARIANTS
static void
vmspace_zdtor(void *mem, int size, void *arg)
{
struct vmspace *vm;
vm = (struct vmspace *)mem;
KASSERT(vm->vm_map.nentries == 0,
("vmspace %p nentries == %d on free", vm, vm->vm_map.nentries));
KASSERT(vm->vm_map.size == 0,
("vmspace %p size == %ju on free", vm, (uintmax_t)vm->vm_map.size));
}
#endif /* INVARIANTS */
/*
* Allocate a vmspace structure, including a vm_map and pmap,
* and initialize those structures. The refcnt is set to 1.
*/
struct vmspace *
vmspace_alloc(vm_offset_t min, vm_offset_t max, pmap_pinit_t pinit)
{
struct vmspace *vm;
vm = uma_zalloc(vmspace_zone, M_WAITOK);
KASSERT(vm->vm_map.pmap == NULL, ("vm_map.pmap must be NULL"));
if (!pinit(vmspace_pmap(vm))) {
uma_zfree(vmspace_zone, vm);
return (NULL);
}
CTR1(KTR_VM, "vmspace_alloc: %p", vm);
_vm_map_init(&vm->vm_map, vmspace_pmap(vm), min, max);
refcount_init(&vm->vm_refcnt, 1);
vm->vm_shm = NULL;
vm->vm_swrss = 0;
vm->vm_tsize = 0;
vm->vm_dsize = 0;
vm->vm_ssize = 0;
vm->vm_taddr = 0;
vm->vm_daddr = 0;
vm->vm_maxsaddr = 0;
return (vm);
}
#ifdef RACCT
static void
vmspace_container_reset(struct proc *p)
{
PROC_LOCK(p);
racct_set(p, RACCT_DATA, 0);
racct_set(p, RACCT_STACK, 0);
racct_set(p, RACCT_RSS, 0);
racct_set(p, RACCT_MEMLOCK, 0);
racct_set(p, RACCT_VMEM, 0);
PROC_UNLOCK(p);
}
#endif
static inline void
vmspace_dofree(struct vmspace *vm)
{
CTR1(KTR_VM, "vmspace_free: %p", vm);
/*
* Make sure any SysV shm is freed, it might not have been in
* exit1().
*/
shmexit(vm);
/*
* Lock the map, to wait out all other references to it.
* Delete all of the mappings and pages they hold, then call
* the pmap module to reclaim anything left.
*/
(void)vm_map_remove(&vm->vm_map, vm_map_min(&vm->vm_map),
vm_map_max(&vm->vm_map));
pmap_release(vmspace_pmap(vm));
vm->vm_map.pmap = NULL;
uma_zfree(vmspace_zone, vm);
}
void
vmspace_free(struct vmspace *vm)
{
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
"vmspace_free() called");
if (refcount_release(&vm->vm_refcnt))
vmspace_dofree(vm);
}
void
vmspace_exitfree(struct proc *p)
{
struct vmspace *vm;
PROC_VMSPACE_LOCK(p);
vm = p->p_vmspace;
p->p_vmspace = NULL;
PROC_VMSPACE_UNLOCK(p);
KASSERT(vm == &vmspace0, ("vmspace_exitfree: wrong vmspace"));
vmspace_free(vm);
}
void
vmspace_exit(struct thread *td)
{
struct vmspace *vm;
struct proc *p;
bool released;
p = td->td_proc;
vm = p->p_vmspace;
/*
* Prepare to release the vmspace reference. The thread that releases
* the last reference is responsible for tearing down the vmspace.
* However, threads not releasing the final reference must switch to the
* kernel's vmspace0 before the decrement so that the subsequent pmap
* deactivation does not modify a freed vmspace.
*/
refcount_acquire(&vmspace0.vm_refcnt);
if (!(released = refcount_release_if_last(&vm->vm_refcnt))) {
if (p->p_vmspace != &vmspace0) {
PROC_VMSPACE_LOCK(p);
p->p_vmspace = &vmspace0;
PROC_VMSPACE_UNLOCK(p);
pmap_activate(td);
}
released = refcount_release(&vm->vm_refcnt);
}
if (released) {
/*
* pmap_remove_pages() expects the pmap to be active, so switch
* back first if necessary.
*/
if (p->p_vmspace != vm) {
PROC_VMSPACE_LOCK(p);
p->p_vmspace = vm;
PROC_VMSPACE_UNLOCK(p);
pmap_activate(td);
}
pmap_remove_pages(vmspace_pmap(vm));
PROC_VMSPACE_LOCK(p);
p->p_vmspace = &vmspace0;
PROC_VMSPACE_UNLOCK(p);
pmap_activate(td);
vmspace_dofree(vm);
}
#ifdef RACCT
if (racct_enable)
vmspace_container_reset(p);
#endif
}
/* Acquire reference to vmspace owned by another process. */
struct vmspace *
vmspace_acquire_ref(struct proc *p)
{
struct vmspace *vm;
PROC_VMSPACE_LOCK(p);
vm = p->p_vmspace;
if (vm == NULL || !refcount_acquire_if_not_zero(&vm->vm_refcnt)) {
PROC_VMSPACE_UNLOCK(p);
return (NULL);
}
if (vm != p->p_vmspace) {
PROC_VMSPACE_UNLOCK(p);
vmspace_free(vm);
return (NULL);
}
PROC_VMSPACE_UNLOCK(p);
return (vm);
}
/*
* Switch between vmspaces in an AIO kernel process.
*
* The new vmspace is either the vmspace of a user process obtained
* from an active AIO request or the initial vmspace of the AIO kernel
* process (when it is idling). Because user processes will block to
* drain any active AIO requests before proceeding in exit() or
* execve(), the reference count for vmspaces from AIO requests can
* never be 0. Similarly, AIO kernel processes hold an extra
* reference on their initial vmspace for the life of the process. As
* a result, the 'newvm' vmspace always has a non-zero reference
* count. This permits an additional reference on 'newvm' to be
* acquired via a simple atomic increment rather than the loop in
* vmspace_acquire_ref() above.
*/
void
vmspace_switch_aio(struct vmspace *newvm)
{
struct vmspace *oldvm;
/* XXX: Need some way to assert that this is an aio daemon. */
KASSERT(refcount_load(&newvm->vm_refcnt) > 0,
("vmspace_switch_aio: newvm unreferenced"));
oldvm = curproc->p_vmspace;
if (oldvm == newvm)
return;
/*
* Point to the new address space and refer to it.
*/
curproc->p_vmspace = newvm;
refcount_acquire(&newvm->vm_refcnt);
/* Activate the new mapping. */
pmap_activate(curthread);
vmspace_free(oldvm);
}
void
_vm_map_lock(vm_map_t map, const char *file, int line)
{
if (map->system_map)
mtx_lock_flags_(&map->system_mtx, 0, file, line);
else
sx_xlock_(&map->lock, file, line);
map->timestamp++;
}
void
vm_map_entry_set_vnode_text(vm_map_entry_t entry, bool add)
{
vm_object_t object;
struct vnode *vp;
bool vp_held;
if ((entry->eflags & MAP_ENTRY_VN_EXEC) == 0)
return;
KASSERT((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0,
("Submap with execs"));
object = entry->object.vm_object;
KASSERT(object != NULL, ("No object for text, entry %p", entry));
if ((object->flags & OBJ_ANON) != 0)
object = object->handle;
else
KASSERT(object->backing_object == NULL,
("non-anon object %p shadows", object));
KASSERT(object != NULL, ("No content object for text, entry %p obj %p",
entry, entry->object.vm_object));
/*
* Mostly, we do not lock the backing object. It is
* referenced by the entry we are processing, so it cannot go
* away.
*/
vm_pager_getvp(object, &vp, &vp_held);
if (vp != NULL) {
if (add) {
VOP_SET_TEXT_CHECKED(vp);
} else {
vn_lock(vp, LK_SHARED | LK_RETRY);
VOP_UNSET_TEXT_CHECKED(vp);
VOP_UNLOCK(vp);
}
if (vp_held)
vdrop(vp);
}
}
/*
* Use a different name for this vm_map_entry field when it's use
* is not consistent with its use as part of an ordered search tree.
*/
#define defer_next right
static void
vm_map_process_deferred(void)
{
struct thread *td;
vm_map_entry_t entry, next;
vm_object_t object;
td = curthread;
entry = td->td_map_def_user;
td->td_map_def_user = NULL;
while (entry != NULL) {
next = entry->defer_next;
MPASS((entry->eflags & (MAP_ENTRY_WRITECNT |
MAP_ENTRY_VN_EXEC)) != (MAP_ENTRY_WRITECNT |
MAP_ENTRY_VN_EXEC));
if ((entry->eflags & MAP_ENTRY_WRITECNT) != 0) {
/*
* Decrement the object's writemappings and
* possibly the vnode's v_writecount.
*/
KASSERT((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0,
("Submap with writecount"));
object = entry->object.vm_object;
KASSERT(object != NULL, ("No object for writecount"));
vm_pager_release_writecount(object, entry->start,
entry->end);
}
vm_map_entry_set_vnode_text(entry, false);
vm_map_entry_deallocate(entry, FALSE);
entry = next;
}
}
#ifdef INVARIANTS
static void
_vm_map_assert_locked(vm_map_t map, const char *file, int line)
{
if (map->system_map)
mtx_assert_(&map->system_mtx, MA_OWNED, file, line);
else
sx_assert_(&map->lock, SA_XLOCKED, file, line);
}
#define VM_MAP_ASSERT_LOCKED(map) \
_vm_map_assert_locked(map, LOCK_FILE, LOCK_LINE)
enum { VMMAP_CHECK_NONE, VMMAP_CHECK_UNLOCK, VMMAP_CHECK_ALL };
#ifdef DIAGNOSTIC
static int enable_vmmap_check = VMMAP_CHECK_UNLOCK;
#else
static int enable_vmmap_check = VMMAP_CHECK_NONE;
#endif
SYSCTL_INT(_debug, OID_AUTO, vmmap_check, CTLFLAG_RWTUN,
&enable_vmmap_check, 0, "Enable vm map consistency checking");
static void _vm_map_assert_consistent(vm_map_t map, int check);
#define VM_MAP_ASSERT_CONSISTENT(map) \
_vm_map_assert_consistent(map, VMMAP_CHECK_ALL)
#ifdef DIAGNOSTIC
#define VM_MAP_UNLOCK_CONSISTENT(map) do { \
if (map->nupdates > map->nentries) { \
_vm_map_assert_consistent(map, VMMAP_CHECK_UNLOCK); \
map->nupdates = 0; \
} \
} while (0)
#else
#define VM_MAP_UNLOCK_CONSISTENT(map)
#endif
#else
#define VM_MAP_ASSERT_LOCKED(map)
#define VM_MAP_ASSERT_CONSISTENT(map)
#define VM_MAP_UNLOCK_CONSISTENT(map)
#endif /* INVARIANTS */
void
_vm_map_unlock(vm_map_t map, const char *file, int line)
{
VM_MAP_UNLOCK_CONSISTENT(map);
if (map->system_map) {
#ifndef UMA_USE_DMAP
if (map == kernel_map && (map->flags & MAP_REPLENISH) != 0) {
uma_prealloc(kmapentzone, 1);
map->flags &= ~MAP_REPLENISH;
}
#endif
mtx_unlock_flags_(&map->system_mtx, 0, file, line);
} else {
sx_xunlock_(&map->lock, file, line);
vm_map_process_deferred();
}
}
void
_vm_map_lock_read(vm_map_t map, const char *file, int line)
{
if (map->system_map)
mtx_lock_flags_(&map->system_mtx, 0, file, line);
else
sx_slock_(&map->lock, file, line);
}
void
_vm_map_unlock_read(vm_map_t map, const char *file, int line)
{
if (map->system_map) {
KASSERT((map->flags & MAP_REPLENISH) == 0,
("%s: MAP_REPLENISH leaked", __func__));
mtx_unlock_flags_(&map->system_mtx, 0, file, line);
} else {
sx_sunlock_(&map->lock, file, line);
vm_map_process_deferred();
}
}
int
_vm_map_trylock(vm_map_t map, const char *file, int line)
{
int error;
error = map->system_map ?
!mtx_trylock_flags_(&map->system_mtx, 0, file, line) :
!sx_try_xlock_(&map->lock, file, line);
if (error == 0)
map->timestamp++;
return (error == 0);
}
int
_vm_map_trylock_read(vm_map_t map, const char *file, int line)
{
int error;
error = map->system_map ?
!mtx_trylock_flags_(&map->system_mtx, 0, file, line) :
!sx_try_slock_(&map->lock, file, line);
return (error == 0);
}
/*
* _vm_map_lock_upgrade: [ internal use only ]
*
* Tries to upgrade a read (shared) lock on the specified map to a write
* (exclusive) lock. Returns the value "0" if the upgrade succeeds and a
* non-zero value if the upgrade fails. If the upgrade fails, the map is
* returned without a read or write lock held.
*
* Requires that the map be read locked.
*/
int
_vm_map_lock_upgrade(vm_map_t map, const char *file, int line)
{
unsigned int last_timestamp;
if (map->system_map) {
mtx_assert_(&map->system_mtx, MA_OWNED, file, line);
} else {
if (!sx_try_upgrade_(&map->lock, file, line)) {
last_timestamp = map->timestamp;
sx_sunlock_(&map->lock, file, line);
vm_map_process_deferred();
/*
* If the map's timestamp does not change while the
* map is unlocked, then the upgrade succeeds.
*/
sx_xlock_(&map->lock, file, line);
if (last_timestamp != map->timestamp) {
sx_xunlock_(&map->lock, file, line);
return (1);
}
}
}
map->timestamp++;
return (0);
}
void
_vm_map_lock_downgrade(vm_map_t map, const char *file, int line)
{
if (map->system_map) {
KASSERT((map->flags & MAP_REPLENISH) == 0,
("%s: MAP_REPLENISH leaked", __func__));
mtx_assert_(&map->system_mtx, MA_OWNED, file, line);
} else {
VM_MAP_UNLOCK_CONSISTENT(map);
sx_downgrade_(&map->lock, file, line);
}
}
/*
* vm_map_locked:
*
* Returns a non-zero value if the caller holds a write (exclusive) lock
* on the specified map and the value "0" otherwise.
*/
int
vm_map_locked(vm_map_t map)
{
if (map->system_map)
return (mtx_owned(&map->system_mtx));
else
return (sx_xlocked(&map->lock));
}
/*
* _vm_map_unlock_and_wait:
*
* Atomically releases the lock on the specified map and puts the calling
* thread to sleep. The calling thread will remain asleep until either
* vm_map_wakeup() is performed on the map or the specified timeout is
* exceeded.
*
* WARNING! This function does not perform deferred deallocations of
* objects and map entries. Therefore, the calling thread is expected to
* reacquire the map lock after reawakening and later perform an ordinary
* unlock operation, such as vm_map_unlock(), before completing its
* operation on the map.
*/
int
_vm_map_unlock_and_wait(vm_map_t map, int timo, const char *file, int line)
{
VM_MAP_UNLOCK_CONSISTENT(map);
mtx_lock(&map_sleep_mtx);
if (map->system_map) {
KASSERT((map->flags & MAP_REPLENISH) == 0,
("%s: MAP_REPLENISH leaked", __func__));
mtx_unlock_flags_(&map->system_mtx, 0, file, line);
} else {
sx_xunlock_(&map->lock, file, line);
}
return (msleep(&map->root, &map_sleep_mtx, PDROP | PVM, "vmmaps",
timo));
}
/*
* vm_map_wakeup:
*
* Awaken any threads that have slept on the map using
* vm_map_unlock_and_wait().
*/
void
vm_map_wakeup(vm_map_t map)
{
/*
* Acquire and release map_sleep_mtx to prevent a wakeup()
* from being performed (and lost) between the map unlock
* and the msleep() in _vm_map_unlock_and_wait().
*/
mtx_lock(&map_sleep_mtx);
mtx_unlock(&map_sleep_mtx);
wakeup(&map->root);
}
void
vm_map_busy(vm_map_t map)
{
VM_MAP_ASSERT_LOCKED(map);
map->busy++;
}
void
vm_map_unbusy(vm_map_t map)
{
VM_MAP_ASSERT_LOCKED(map);
KASSERT(map->busy, ("vm_map_unbusy: not busy"));
if (--map->busy == 0 && (map->flags & MAP_BUSY_WAKEUP)) {
vm_map_modflags(map, 0, MAP_BUSY_WAKEUP);
wakeup(&map->busy);
}
}
void
vm_map_wait_busy(vm_map_t map)
{
VM_MAP_ASSERT_LOCKED(map);
while (map->busy) {
vm_map_modflags(map, MAP_BUSY_WAKEUP, 0);
if (map->system_map)
msleep(&map->busy, &map->system_mtx, 0, "mbusy", 0);
else
sx_sleep(&map->busy, &map->lock, 0, "mbusy", 0);
}
map->timestamp++;
}
long
vmspace_resident_count(struct vmspace *vmspace)
{
return pmap_resident_count(vmspace_pmap(vmspace));
}
/*
* Initialize an existing vm_map structure
* such as that in the vmspace structure.
*/
static void
_vm_map_init(vm_map_t map, pmap_t pmap, vm_offset_t min, vm_offset_t max)
{
map->header.eflags = MAP_ENTRY_HEADER;
map->needs_wakeup = FALSE;
map->system_map = 0;
map->pmap = pmap;
map->header.end = min;
map->header.start = max;
map->flags = 0;
map->header.left = map->header.right = &map->header;
map->root = NULL;
map->timestamp = 0;
map->busy = 0;
map->anon_loc = 0;
#ifdef DIAGNOSTIC
map->nupdates = 0;
#endif
}
void
vm_map_init(vm_map_t map, pmap_t pmap, vm_offset_t min, vm_offset_t max)
{
_vm_map_init(map, pmap, min, max);
mtx_init(&map->system_mtx, "vm map (system)", NULL,
MTX_DEF | MTX_DUPOK);
sx_init(&map->lock, "vm map (user)");
}
/*
* vm_map_entry_dispose: [ internal use only ]
*
* Inverse of vm_map_entry_create.
*/
static void
vm_map_entry_dispose(vm_map_t map, vm_map_entry_t entry)
{
uma_zfree(map->system_map ? kmapentzone : mapentzone, entry);
}
/*
* vm_map_entry_create: [ internal use only ]
*
* Allocates a VM map entry for insertion.
* No entry fields are filled in.
*/
static vm_map_entry_t
vm_map_entry_create(vm_map_t map)
{
vm_map_entry_t new_entry;
#ifndef UMA_USE_DMAP
if (map == kernel_map) {
VM_MAP_ASSERT_LOCKED(map);
/*
* A new slab of kernel map entries cannot be allocated at this
* point because the kernel map has not yet been updated to
* reflect the caller's request. Therefore, we allocate a new
* map entry, dipping into the reserve if necessary, and set a
* flag indicating that the reserve must be replenished before
* the map is unlocked.
*/
new_entry = uma_zalloc(kmapentzone, M_NOWAIT | M_NOVM);
if (new_entry == NULL) {
new_entry = uma_zalloc(kmapentzone,
M_NOWAIT | M_NOVM | M_USE_RESERVE);
kernel_map->flags |= MAP_REPLENISH;
}
} else
#endif
if (map->system_map) {
new_entry = uma_zalloc(kmapentzone, M_NOWAIT);
} else {
new_entry = uma_zalloc(mapentzone, M_WAITOK);
}
KASSERT(new_entry != NULL,
("vm_map_entry_create: kernel resources exhausted"));
return (new_entry);
}
/*
* vm_map_entry_set_behavior:
*
* Set the expected access behavior, either normal, random, or
* sequential.
*/
static inline void
vm_map_entry_set_behavior(vm_map_entry_t entry, u_char behavior)
{
entry->eflags = (entry->eflags & ~MAP_ENTRY_BEHAV_MASK) |
(behavior & MAP_ENTRY_BEHAV_MASK);
}
/*
* vm_map_entry_max_free_{left,right}:
*
* Compute the size of the largest free gap between two entries,
* one the root of a tree and the other the ancestor of that root
* that is the least or greatest ancestor found on the search path.
*/
static inline vm_size_t
vm_map_entry_max_free_left(vm_map_entry_t root, vm_map_entry_t left_ancestor)
{
return (root->left != left_ancestor ?
root->left->max_free : root->start - left_ancestor->end);
}
static inline vm_size_t
vm_map_entry_max_free_right(vm_map_entry_t root, vm_map_entry_t right_ancestor)
{
return (root->right != right_ancestor ?
root->right->max_free : right_ancestor->start - root->end);
}
/*
* vm_map_entry_{pred,succ}:
*
* Find the {predecessor, successor} of the entry by taking one step
* in the appropriate direction and backtracking as much as necessary.
* vm_map_entry_succ is defined in vm_map.h.
*/
static inline vm_map_entry_t
vm_map_entry_pred(vm_map_entry_t entry)
{
vm_map_entry_t prior;
prior = entry->left;
if (prior->right->start < entry->start) {
do
prior = prior->right;
while (prior->right != entry);
}
return (prior);
}
static inline vm_size_t
vm_size_max(vm_size_t a, vm_size_t b)
{
return (a > b ? a : b);
}
#define SPLAY_LEFT_STEP(root, y, llist, rlist, test) do { \
vm_map_entry_t z; \
vm_size_t max_free; \
\
/* \
* Infer root->right->max_free == root->max_free when \
* y->max_free < root->max_free || root->max_free == 0. \
* Otherwise, look right to find it. \
*/ \
y = root->left; \
max_free = root->max_free; \
KASSERT(max_free == vm_size_max( \
vm_map_entry_max_free_left(root, llist), \
vm_map_entry_max_free_right(root, rlist)), \
("%s: max_free invariant fails", __func__)); \
if (max_free - 1 < vm_map_entry_max_free_left(root, llist)) \
max_free = vm_map_entry_max_free_right(root, rlist); \
if (y != llist && (test)) { \
/* Rotate right and make y root. */ \
z = y->right; \
if (z != root) { \
root->left = z; \
y->right = root; \
if (max_free < y->max_free) \
root->max_free = max_free = \
vm_size_max(max_free, z->max_free); \
} else if (max_free < y->max_free) \
root->max_free = max_free = \
vm_size_max(max_free, root->start - y->end);\
root = y; \
y = root->left; \
} \
/* Copy right->max_free. Put root on rlist. */ \
root->max_free = max_free; \
KASSERT(max_free == vm_map_entry_max_free_right(root, rlist), \
("%s: max_free not copied from right", __func__)); \
root->left = rlist; \
rlist = root; \
root = y != llist ? y : NULL; \
} while (0)
#define SPLAY_RIGHT_STEP(root, y, llist, rlist, test) do { \
vm_map_entry_t z; \
vm_size_t max_free; \
\
/* \
* Infer root->left->max_free == root->max_free when \
* y->max_free < root->max_free || root->max_free == 0. \
* Otherwise, look left to find it. \
*/ \
y = root->right; \
max_free = root->max_free; \
KASSERT(max_free == vm_size_max( \
vm_map_entry_max_free_left(root, llist), \
vm_map_entry_max_free_right(root, rlist)), \
("%s: max_free invariant fails", __func__)); \
if (max_free - 1 < vm_map_entry_max_free_right(root, rlist)) \
max_free = vm_map_entry_max_free_left(root, llist); \
if (y != rlist && (test)) { \
/* Rotate left and make y root. */ \
z = y->left; \
if (z != root) { \
root->right = z; \
y->left = root; \
if (max_free < y->max_free) \
root->max_free = max_free = \
vm_size_max(max_free, z->max_free); \
} else if (max_free < y->max_free) \
root->max_free = max_free = \
vm_size_max(max_free, y->start - root->end);\
root = y; \
y = root->right; \
} \
/* Copy left->max_free. Put root on llist. */ \
root->max_free = max_free; \
KASSERT(max_free == vm_map_entry_max_free_left(root, llist), \
("%s: max_free not copied from left", __func__)); \
root->right = llist; \
llist = root; \
root = y != rlist ? y : NULL; \
} while (0)
/*
* Walk down the tree until we find addr or a gap where addr would go, breaking
* off left and right subtrees of nodes less than, or greater than addr. Treat
* subtrees with root->max_free < length as empty trees. llist and rlist are
* the two sides in reverse order (bottom-up), with llist linked by the right
* pointer and rlist linked by the left pointer in the vm_map_entry, and both
* lists terminated by &map->header. This function, and the subsequent call to
* vm_map_splay_merge_{left,right,pred,succ}, rely on the start and end address
* values in &map->header.
*/
static __always_inline vm_map_entry_t
vm_map_splay_split(vm_map_t map, vm_offset_t addr, vm_size_t length,
vm_map_entry_t *llist, vm_map_entry_t *rlist)
{
vm_map_entry_t left, right, root, y;
left = right = &map->header;
root = map->root;
while (root != NULL && root->max_free >= length) {
KASSERT(left->end <= root->start &&
root->end <= right->start,
("%s: root not within tree bounds", __func__));
if (addr < root->start) {
SPLAY_LEFT_STEP(root, y, left, right,
y->max_free >= length && addr < y->start);
} else if (addr >= root->end) {
SPLAY_RIGHT_STEP(root, y, left, right,
y->max_free >= length && addr >= y->end);
} else
break;
}
*llist = left;
*rlist = right;
return (root);
}
static __always_inline void
vm_map_splay_findnext(vm_map_entry_t root, vm_map_entry_t *rlist)
{
vm_map_entry_t hi, right, y;
right = *rlist;
hi = root->right == right ? NULL : root->right;
if (hi == NULL)
return;
do
SPLAY_LEFT_STEP(hi, y, root, right, true);
while (hi != NULL);
*rlist = right;
}
static __always_inline void
vm_map_splay_findprev(vm_map_entry_t root, vm_map_entry_t *llist)
{
vm_map_entry_t left, lo, y;
left = *llist;
lo = root->left == left ? NULL : root->left;
if (lo == NULL)
return;
do
SPLAY_RIGHT_STEP(lo, y, left, root, true);
while (lo != NULL);
*llist = left;
}
static inline void
vm_map_entry_swap(vm_map_entry_t *a, vm_map_entry_t *b)
{
vm_map_entry_t tmp;
tmp = *b;
*b = *a;
*a = tmp;
}
/*
* Walk back up the two spines, flip the pointers and set max_free. The
* subtrees of the root go at the bottom of llist and rlist.
*/
static vm_size_t
vm_map_splay_merge_left_walk(vm_map_entry_t header, vm_map_entry_t root,
vm_map_entry_t tail, vm_size_t max_free, vm_map_entry_t llist)
{
do {
/*
* The max_free values of the children of llist are in
* llist->max_free and max_free. Update with the
* max value.
*/
llist->max_free = max_free =
vm_size_max(llist->max_free, max_free);
vm_map_entry_swap(&llist->right, &tail);
vm_map_entry_swap(&tail, &llist);
} while (llist != header);
root->left = tail;
return (max_free);
}
/*
* When llist is known to be the predecessor of root.
*/
static inline vm_size_t
vm_map_splay_merge_pred(vm_map_entry_t header, vm_map_entry_t root,
vm_map_entry_t llist)
{
vm_size_t max_free;
max_free = root->start - llist->end;
if (llist != header) {
max_free = vm_map_splay_merge_left_walk(header, root,
root, max_free, llist);
} else {
root->left = header;
header->right = root;
}
return (max_free);
}
/*
* When llist may or may not be the predecessor of root.
*/
static inline vm_size_t
vm_map_splay_merge_left(vm_map_entry_t header, vm_map_entry_t root,
vm_map_entry_t llist)
{
vm_size_t max_free;
max_free = vm_map_entry_max_free_left(root, llist);
if (llist != header) {
max_free = vm_map_splay_merge_left_walk(header, root,
root->left == llist ? root : root->left,
max_free, llist);
}
return (max_free);
}
static vm_size_t
vm_map_splay_merge_right_walk(vm_map_entry_t header, vm_map_entry_t root,
vm_map_entry_t tail, vm_size_t max_free, vm_map_entry_t rlist)
{
do {
/*
* The max_free values of the children of rlist are in
* rlist->max_free and max_free. Update with the
* max value.
*/
rlist->max_free = max_free =
vm_size_max(rlist->max_free, max_free);
vm_map_entry_swap(&rlist->left, &tail);
vm_map_entry_swap(&tail, &rlist);
} while (rlist != header);
root->right = tail;
return (max_free);
}
/*
* When rlist is known to be the succecessor of root.
*/
static inline vm_size_t
vm_map_splay_merge_succ(vm_map_entry_t header, vm_map_entry_t root,
vm_map_entry_t rlist)
{
vm_size_t max_free;
max_free = rlist->start - root->end;
if (rlist != header) {
max_free = vm_map_splay_merge_right_walk(header, root,
root, max_free, rlist);
} else {
root->right = header;
header->left = root;
}
return (max_free);
}
/*
* When rlist may or may not be the succecessor of root.
*/
static inline vm_size_t
vm_map_splay_merge_right(vm_map_entry_t header, vm_map_entry_t root,
vm_map_entry_t rlist)
{
vm_size_t max_free;
max_free = vm_map_entry_max_free_right(root, rlist);
if (rlist != header) {
max_free = vm_map_splay_merge_right_walk(header, root,
root->right == rlist ? root : root->right,
max_free, rlist);
}
return (max_free);
}
/*
* vm_map_splay:
*
* The Sleator and Tarjan top-down splay algorithm with the
* following variation. Max_free must be computed bottom-up, so
* on the downward pass, maintain the left and right spines in
* reverse order. Then, make a second pass up each side to fix
* the pointers and compute max_free. The time bound is O(log n)
* amortized.
*
* The tree is threaded, which means that there are no null pointers.
* When a node has no left child, its left pointer points to its
* predecessor, which the last ancestor on the search path from the root
* where the search branched right. Likewise, when a node has no right
* child, its right pointer points to its successor. The map header node
* is the predecessor of the first map entry, and the successor of the
* last.
*
* The new root is the vm_map_entry containing "addr", or else an
* adjacent entry (lower if possible) if addr is not in the tree.
*
* The map must be locked, and leaves it so.
*
* Returns: the new root.
*/
static vm_map_entry_t
vm_map_splay(vm_map_t map, vm_offset_t addr)
{
vm_map_entry_t header, llist, rlist, root;
vm_size_t max_free_left, max_free_right;
header = &map->header;
root = vm_map_splay_split(map, addr, 0, &llist, &rlist);
if (root != NULL) {
max_free_left = vm_map_splay_merge_left(header, root, llist);
max_free_right = vm_map_splay_merge_right(header, root, rlist);
} else if (llist != header) {
/*
* Recover the greatest node in the left
* subtree and make it the root.
*/
root = llist;
llist = root->right;
max_free_left = vm_map_splay_merge_left(header, root, llist);
max_free_right = vm_map_splay_merge_succ(header, root, rlist);
} else if (rlist != header) {
/*
* Recover the least node in the right
* subtree and make it the root.
*/
root = rlist;
rlist = root->left;
max_free_left = vm_map_splay_merge_pred(header, root, llist);
max_free_right = vm_map_splay_merge_right(header, root, rlist);
} else {
/* There is no root. */
return (NULL);
}
root->max_free = vm_size_max(max_free_left, max_free_right);
map->root = root;
VM_MAP_ASSERT_CONSISTENT(map);
return (root);
}
/*
* vm_map_entry_{un,}link:
*
* Insert/remove entries from maps. On linking, if new entry clips
* existing entry, trim existing entry to avoid overlap, and manage
* offsets. On unlinking, merge disappearing entry with neighbor, if
* called for, and manage offsets. Callers should not modify fields in
* entries already mapped.
*/
static void
vm_map_entry_link(vm_map_t map, vm_map_entry_t entry)
{
vm_map_entry_t header, llist, rlist, root;
vm_size_t max_free_left, max_free_right;
CTR3(KTR_VM,
"vm_map_entry_link: map %p, nentries %d, entry %p", map,
map->nentries, entry);
VM_MAP_ASSERT_LOCKED(map);
map->nentries++;
header = &map->header;
root = vm_map_splay_split(map, entry->start, 0, &llist, &rlist);
if (root == NULL) {
/*
* The new entry does not overlap any existing entry in the
* map, so it becomes the new root of the map tree.
*/
max_free_left = vm_map_splay_merge_pred(header, entry, llist);
max_free_right = vm_map_splay_merge_succ(header, entry, rlist);
} else if (entry->start == root->start) {
/*
* The new entry is a clone of root, with only the end field
* changed. The root entry will be shrunk to abut the new
* entry, and will be the right child of the new root entry in
* the modified map.
*/
KASSERT(entry->end < root->end,
("%s: clip_start not within entry", __func__));
vm_map_splay_findprev(root, &llist);
if ((root->eflags & (MAP_ENTRY_STACK_GAP_DN |
MAP_ENTRY_STACK_GAP_UP)) == 0)
root->offset += entry->end - root->start;
root->start = entry->end;
max_free_left = vm_map_splay_merge_pred(header, entry, llist);
max_free_right = root->max_free = vm_size_max(
vm_map_splay_merge_pred(entry, root, entry),
vm_map_splay_merge_right(header, root, rlist));
} else {
/*
* The new entry is a clone of root, with only the start field
* changed. The root entry will be shrunk to abut the new
* entry, and will be the left child of the new root entry in
* the modified map.
*/
KASSERT(entry->end == root->end,
("%s: clip_start not within entry", __func__));
vm_map_splay_findnext(root, &rlist);
if ((entry->eflags & (MAP_ENTRY_STACK_GAP_DN |
MAP_ENTRY_STACK_GAP_UP)) == 0)
entry->offset += entry->start - root->start;
root->end = entry->start;
max_free_left = root->max_free = vm_size_max(
vm_map_splay_merge_left(header, root, llist),
vm_map_splay_merge_succ(entry, root, entry));
max_free_right = vm_map_splay_merge_succ(header, entry, rlist);
}
entry->max_free = vm_size_max(max_free_left, max_free_right);
map->root = entry;
VM_MAP_ASSERT_CONSISTENT(map);
}
enum unlink_merge_type {
UNLINK_MERGE_NONE,
UNLINK_MERGE_NEXT
};
static void
vm_map_entry_unlink(vm_map_t map, vm_map_entry_t entry,
enum unlink_merge_type op)
{
vm_map_entry_t header, llist, rlist, root;
vm_size_t max_free_left, max_free_right;
VM_MAP_ASSERT_LOCKED(map);
header = &map->header;
root = vm_map_splay_split(map, entry->start, 0, &llist, &rlist);
KASSERT(root != NULL,
("vm_map_entry_unlink: unlink object not mapped"));
vm_map_splay_findprev(root, &llist);
vm_map_splay_findnext(root, &rlist);
if (op == UNLINK_MERGE_NEXT) {
rlist->start = root->start;
MPASS((rlist->eflags & (MAP_ENTRY_STACK_GAP_DN |
MAP_ENTRY_STACK_GAP_UP)) == 0);
rlist->offset = root->offset;
}
if (llist != header) {
root = llist;
llist = root->right;
max_free_left = vm_map_splay_merge_left(header, root, llist);
max_free_right = vm_map_splay_merge_succ(header, root, rlist);
} else if (rlist != header) {
root = rlist;
rlist = root->left;
max_free_left = vm_map_splay_merge_pred(header, root, llist);
max_free_right = vm_map_splay_merge_right(header, root, rlist);
} else {
header->left = header->right = header;
root = NULL;
}
if (root != NULL)
root->max_free = vm_size_max(max_free_left, max_free_right);
map->root = root;
VM_MAP_ASSERT_CONSISTENT(map);
map->nentries--;
CTR3(KTR_VM, "vm_map_entry_unlink: map %p, nentries %d, entry %p", map,
map->nentries, entry);
}
/*
* vm_map_entry_resize:
*
* Resize a vm_map_entry, recompute the amount of free space that
* follows it and propagate that value up the tree.
*
* The map must be locked, and leaves it so.
*/
static void
vm_map_entry_resize(vm_map_t map, vm_map_entry_t entry, vm_size_t grow_amount)
{
vm_map_entry_t header, llist, rlist, root;
VM_MAP_ASSERT_LOCKED(map);
header = &map->header;
root = vm_map_splay_split(map, entry->start, 0, &llist, &rlist);
KASSERT(root != NULL, ("%s: resize object not mapped", __func__));
vm_map_splay_findnext(root, &rlist);
entry->end += grow_amount;
root->max_free = vm_size_max(
vm_map_splay_merge_left(header, root, llist),
vm_map_splay_merge_succ(header, root, rlist));
map->root = root;
VM_MAP_ASSERT_CONSISTENT(map);
CTR4(KTR_VM, "%s: map %p, nentries %d, entry %p",
__func__, map, map->nentries, entry);
}
/*
* vm_map_lookup_entry: [ internal use only ]
*
* Finds the map entry containing (or
* immediately preceding) the specified address
* in the given map; the entry is returned
* in the "entry" parameter. The boolean
* result indicates whether the address is
* actually contained in the map.
*/
boolean_t
vm_map_lookup_entry(
vm_map_t map,
vm_offset_t address,
vm_map_entry_t *entry) /* OUT */
{
vm_map_entry_t cur, header, lbound, ubound;
boolean_t locked;
/*
* If the map is empty, then the map entry immediately preceding
* "address" is the map's header.
*/
header = &map->header;
cur = map->root;
if (cur == NULL) {
*entry = header;
return (FALSE);
}
if (address >= cur->start && cur->end > address) {
*entry = cur;
return (TRUE);
}
if ((locked = vm_map_locked(map)) ||
sx_try_upgrade(&map->lock)) {
/*
* Splay requires a write lock on the map. However, it only
* restructures the binary search tree; it does not otherwise
* change the map. Thus, the map's timestamp need not change
* on a temporary upgrade.
*/
cur = vm_map_splay(map, address);
if (!locked) {
VM_MAP_UNLOCK_CONSISTENT(map);
sx_downgrade(&map->lock);
}
/*
* If "address" is contained within a map entry, the new root
* is that map entry. Otherwise, the new root is a map entry
* immediately before or after "address".
*/
if (address < cur->start) {
*entry = header;
return (FALSE);
}
*entry = cur;
return (address < cur->end);
}
/*
* Since the map is only locked for read access, perform a
* standard binary search tree lookup for "address".
*/
lbound = ubound = header;
for (;;) {
if (address < cur->start) {
ubound = cur;
cur = cur->left;
if (cur == lbound)
break;
} else if (cur->end <= address) {
lbound = cur;
cur = cur->right;
if (cur == ubound)
break;
} else {
*entry = cur;
return (TRUE);
}
}
*entry = lbound;
return (FALSE);
}
/*
* vm_map_insert1() is identical to vm_map_insert() except that it
* returns the newly inserted map entry in '*res'. In case the new
* entry is coalesced with a neighbor or an existing entry was
* resized, that entry is returned. In any case, the returned entry
* covers the specified address range.
*/
static int
vm_map_insert1(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
vm_offset_t start, vm_offset_t end, vm_prot_t prot, vm_prot_t max, int cow,
vm_map_entry_t *res)
{
vm_map_entry_t new_entry, next_entry, prev_entry;
struct ucred *cred;
vm_eflags_t protoeflags;
vm_inherit_t inheritance;
u_long bdry;
u_int bidx;
VM_MAP_ASSERT_LOCKED(map);
KASSERT(object != kernel_object ||
(cow & MAP_COPY_ON_WRITE) == 0,
("vm_map_insert: kernel object and COW"));
KASSERT(object == NULL || (cow & MAP_NOFAULT) == 0 ||
(cow & MAP_SPLIT_BOUNDARY_MASK) != 0,
("vm_map_insert: paradoxical MAP_NOFAULT request, obj %p cow %#x",
object, cow));
KASSERT((prot & ~max) == 0,
("prot %#x is not subset of max_prot %#x", prot, max));
/*
* Check that the start and end points are not bogus.
*/
if (start == end || !vm_map_range_valid(map, start, end))
return (KERN_INVALID_ADDRESS);
if ((map->flags & MAP_WXORX) != 0 && (prot & (VM_PROT_WRITE |
VM_PROT_EXECUTE)) == (VM_PROT_WRITE | VM_PROT_EXECUTE))
return (KERN_PROTECTION_FAILURE);
/*
* Find the entry prior to the proposed starting address; if it's part
* of an existing entry, this range is bogus.
*/
if (vm_map_lookup_entry(map, start, &prev_entry))
return (KERN_NO_SPACE);
/*
* Assert that the next entry doesn't overlap the end point.
*/
next_entry = vm_map_entry_succ(prev_entry);
if (next_entry->start < end)
return (KERN_NO_SPACE);
if ((cow & MAP_CREATE_GUARD) != 0 && (object != NULL ||
max != VM_PROT_NONE))
return (KERN_INVALID_ARGUMENT);
protoeflags = 0;
if (cow & MAP_COPY_ON_WRITE)
protoeflags |= MAP_ENTRY_COW | MAP_ENTRY_NEEDS_COPY;
if (cow & MAP_NOFAULT)
protoeflags |= MAP_ENTRY_NOFAULT;
if (cow & MAP_DISABLE_SYNCER)
protoeflags |= MAP_ENTRY_NOSYNC;
if (cow & MAP_DISABLE_COREDUMP)
protoeflags |= MAP_ENTRY_NOCOREDUMP;
if (cow & MAP_STACK_GROWS_DOWN)
protoeflags |= MAP_ENTRY_GROWS_DOWN;
if (cow & MAP_STACK_GROWS_UP)
protoeflags |= MAP_ENTRY_GROWS_UP;
if (cow & MAP_WRITECOUNT)
protoeflags |= MAP_ENTRY_WRITECNT;
if (cow & MAP_VN_EXEC)
protoeflags |= MAP_ENTRY_VN_EXEC;
if ((cow & MAP_CREATE_GUARD) != 0)
protoeflags |= MAP_ENTRY_GUARD;
if ((cow & MAP_CREATE_STACK_GAP_DN) != 0)
protoeflags |= MAP_ENTRY_STACK_GAP_DN;
if ((cow & MAP_CREATE_STACK_GAP_UP) != 0)
protoeflags |= MAP_ENTRY_STACK_GAP_UP;
if (cow & MAP_INHERIT_SHARE)
inheritance = VM_INHERIT_SHARE;
else
inheritance = VM_INHERIT_DEFAULT;
if ((cow & MAP_SPLIT_BOUNDARY_MASK) != 0) {
/* This magically ignores index 0, for usual page size. */
bidx = (cow & MAP_SPLIT_BOUNDARY_MASK) >>
MAP_SPLIT_BOUNDARY_SHIFT;
if (bidx >= MAXPAGESIZES)
return (KERN_INVALID_ARGUMENT);
bdry = pagesizes[bidx] - 1;
if ((start & bdry) != 0 || (end & bdry) != 0)
return (KERN_INVALID_ARGUMENT);
protoeflags |= bidx << MAP_ENTRY_SPLIT_BOUNDARY_SHIFT;
}
cred = NULL;
if ((cow & (MAP_ACC_NO_CHARGE | MAP_NOFAULT | MAP_CREATE_GUARD)) != 0)
goto charged;
if ((cow & MAP_ACC_CHARGED) || ((prot & VM_PROT_WRITE) &&
((protoeflags & MAP_ENTRY_NEEDS_COPY) || object == NULL))) {
if (!(cow & MAP_ACC_CHARGED) && !swap_reserve(end - start))
return (KERN_RESOURCE_SHORTAGE);
KASSERT(object == NULL ||
(protoeflags & MAP_ENTRY_NEEDS_COPY) != 0 ||
object->cred == NULL,
("overcommit: vm_map_insert o %p", object));
cred = curthread->td_ucred;
}
charged:
/* Expand the kernel pmap, if necessary. */
if (map == kernel_map && end > kernel_vm_end)
pmap_growkernel(end);
if (object != NULL) {
/*
* OBJ_ONEMAPPING must be cleared unless this mapping
* is trivially proven to be the only mapping for any
* of the object's pages. (Object granularity
* reference counting is insufficient to recognize
* aliases with precision.)
*/
if ((object->flags & OBJ_ANON) != 0) {
VM_OBJECT_WLOCK(object);
if (object->ref_count > 1 || object->shadow_count != 0)
vm_object_clear_flag(object, OBJ_ONEMAPPING);
VM_OBJECT_WUNLOCK(object);
}
} else if ((prev_entry->eflags & ~MAP_ENTRY_USER_WIRED) ==
protoeflags &&
(cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP |
MAP_VN_EXEC)) == 0 &&
prev_entry->end == start && (prev_entry->cred == cred ||
(prev_entry->object.vm_object != NULL &&
prev_entry->object.vm_object->cred == cred)) &&
vm_object_coalesce(prev_entry->object.vm_object,
prev_entry->offset,
(vm_size_t)(prev_entry->end - prev_entry->start),
(vm_size_t)(end - prev_entry->end), cred != NULL &&
(protoeflags & MAP_ENTRY_NEEDS_COPY) == 0)) {
/*
* We were able to extend the object. Determine if we
* can extend the previous map entry to include the
* new range as well.
*/
if (prev_entry->inheritance == inheritance &&
prev_entry->protection == prot &&
prev_entry->max_protection == max &&
prev_entry->wired_count == 0) {
KASSERT((prev_entry->eflags & MAP_ENTRY_USER_WIRED) ==
0, ("prev_entry %p has incoherent wiring",
prev_entry));
if ((prev_entry->eflags & MAP_ENTRY_GUARD) == 0)
map->size += end - prev_entry->end;
vm_map_entry_resize(map, prev_entry,
end - prev_entry->end);
*res = vm_map_try_merge_entries(map, prev_entry,
next_entry);
return (KERN_SUCCESS);
}
/*
* If we can extend the object but cannot extend the
* map entry, we have to create a new map entry. We
* must bump the ref count on the extended object to
* account for it. object may be NULL.
*/
object = prev_entry->object.vm_object;
offset = prev_entry->offset +
(prev_entry->end - prev_entry->start);
vm_object_reference(object);
if (cred != NULL && object != NULL && object->cred != NULL &&
!(prev_entry->eflags & MAP_ENTRY_NEEDS_COPY)) {
/* Object already accounts for this uid. */
cred = NULL;
}
}
if (cred != NULL)
crhold(cred);
/*
* Create a new entry
*/
new_entry = vm_map_entry_create(map);
new_entry->start = start;
new_entry->end = end;
new_entry->cred = NULL;
new_entry->eflags = protoeflags;
new_entry->object.vm_object = object;
new_entry->offset = offset;
new_entry->inheritance = inheritance;
new_entry->protection = prot;
new_entry->max_protection = max;
new_entry->wired_count = 0;
new_entry->wiring_thread = NULL;
new_entry->read_ahead = VM_FAULT_READ_AHEAD_INIT;
new_entry->next_read = start;
KASSERT(cred == NULL || !ENTRY_CHARGED(new_entry),
("overcommit: vm_map_insert leaks vm_map %p", new_entry));
new_entry->cred = cred;
/*
* Insert the new entry into the list
*/
vm_map_entry_link(map, new_entry);
if ((new_entry->eflags & MAP_ENTRY_GUARD) == 0)
map->size += new_entry->end - new_entry->start;
/*
* Try to coalesce the new entry with both the previous and next
* entries in the list. Previously, we only attempted to coalesce
* with the previous entry when object is NULL. Here, we handle the
* other cases, which are less common.
*/
vm_map_try_merge_entries(map, prev_entry, new_entry);
*res = vm_map_try_merge_entries(map, new_entry, next_entry);
if ((cow & (MAP_PREFAULT | MAP_PREFAULT_PARTIAL)) != 0) {
vm_map_pmap_enter(map, start, prot, object, OFF_TO_IDX(offset),
end - start, cow & MAP_PREFAULT_PARTIAL);
}
return (KERN_SUCCESS);
}
/*
* vm_map_insert:
*
* Inserts the given VM object into the target map at the
* specified address range.
*
* Requires that the map be locked, and leaves it so.
*
* If object is non-NULL, ref count must be bumped by caller
* prior to making call to account for the new entry.
*/
int
vm_map_insert(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
vm_offset_t start, vm_offset_t end, vm_prot_t prot, vm_prot_t max, int cow)
{
vm_map_entry_t res;
return (vm_map_insert1(map, object, offset, start, end, prot, max,
cow, &res));
}
/*
* vm_map_findspace:
*
* Find the first fit (lowest VM address) for "length" free bytes
* beginning at address >= start in the given map.
*
* In a vm_map_entry, "max_free" is the maximum amount of
* contiguous free space between an entry in its subtree and a
* neighbor of that entry. This allows finding a free region in
* one path down the tree, so O(log n) amortized with splay
* trees.
*
* The map must be locked, and leaves it so.
*
* Returns: starting address if sufficient space,
* vm_map_max(map)-length+1 if insufficient space.
*/
vm_offset_t
vm_map_findspace(vm_map_t map, vm_offset_t start, vm_size_t length)
{
vm_map_entry_t header, llist, rlist, root, y;
vm_size_t left_length, max_free_left, max_free_right;
vm_offset_t gap_end;
VM_MAP_ASSERT_LOCKED(map);
/*
* Request must fit within min/max VM address and must avoid
* address wrap.
*/
start = MAX(start, vm_map_min(map));
if (start >= vm_map_max(map) || length > vm_map_max(map) - start)
return (vm_map_max(map) - length + 1);
/* Empty tree means wide open address space. */
if (map->root == NULL)
return (start);
/*
* After splay_split, if start is within an entry, push it to the start
* of the following gap. If rlist is at the end of the gap containing
* start, save the end of that gap in gap_end to see if the gap is big
* enough; otherwise set gap_end to start skip gap-checking and move
* directly to a search of the right subtree.
*/
header = &map->header;
root = vm_map_splay_split(map, start, length, &llist, &rlist);
gap_end = rlist->start;
if (root != NULL) {
start = root->end;
if (root->right != rlist)
gap_end = start;
max_free_left = vm_map_splay_merge_left(header, root, llist);
max_free_right = vm_map_splay_merge_right(header, root, rlist);
} else if (rlist != header) {
root = rlist;
rlist = root->left;
max_free_left = vm_map_splay_merge_pred(header, root, llist);
max_free_right = vm_map_splay_merge_right(header, root, rlist);
} else {
root = llist;
llist = root->right;
max_free_left = vm_map_splay_merge_left(header, root, llist);
max_free_right = vm_map_splay_merge_succ(header, root, rlist);
}
root->max_free = vm_size_max(max_free_left, max_free_right);
map->root = root;
VM_MAP_ASSERT_CONSISTENT(map);
if (length <= gap_end - start)
return (start);
/* With max_free, can immediately tell if no solution. */
if (root->right == header || length > root->right->max_free)
return (vm_map_max(map) - length + 1);
/*
* Splay for the least large-enough gap in the right subtree.
*/
llist = rlist = header;
for (left_length = 0;;
left_length = vm_map_entry_max_free_left(root, llist)) {
if (length <= left_length)
SPLAY_LEFT_STEP(root, y, llist, rlist,
length <= vm_map_entry_max_free_left(y, llist));
else
SPLAY_RIGHT_STEP(root, y, llist, rlist,
length > vm_map_entry_max_free_left(y, root));
if (root == NULL)
break;
}
root = llist;
llist = root->right;
max_free_left = vm_map_splay_merge_left(header, root, llist);
if (rlist == header) {
root->max_free = vm_size_max(max_free_left,
vm_map_splay_merge_succ(header, root, rlist));
} else {
y = rlist;
rlist = y->left;
y->max_free = vm_size_max(
vm_map_splay_merge_pred(root, y, root),
vm_map_splay_merge_right(header, y, rlist));
root->max_free = vm_size_max(max_free_left, y->max_free);
}
map->root = root;
VM_MAP_ASSERT_CONSISTENT(map);
return (root->end);
}
int
vm_map_fixed(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
vm_offset_t start, vm_size_t length, vm_prot_t prot,
vm_prot_t max, int cow)
{
vm_offset_t end;
int result;
end = start + length;
KASSERT((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) == 0 ||
object == NULL,
("vm_map_fixed: non-NULL backing object for stack"));
vm_map_lock(map);
VM_MAP_RANGE_CHECK(map, start, end);
if ((cow & MAP_CHECK_EXCL) == 0) {
result = vm_map_delete(map, start, end);
if (result != KERN_SUCCESS)
goto out;
}
if ((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) != 0) {
result = vm_map_stack_locked(map, start, length, sgrowsiz,
prot, max, cow);
} else {
result = vm_map_insert(map, object, offset, start, end,
prot, max, cow);
}
out:
vm_map_unlock(map);
return (result);
}
static const int aslr_pages_rnd_64[2] = {0x1000, 0x10};
static const int aslr_pages_rnd_32[2] = {0x100, 0x4};
static int cluster_anon = 1;
SYSCTL_INT(_vm, OID_AUTO, cluster_anon, CTLFLAG_RW,
&cluster_anon, 0,
"Cluster anonymous mappings: 0 = no, 1 = yes if no hint, 2 = always");
static bool
clustering_anon_allowed(vm_offset_t addr, int cow)
{
switch (cluster_anon) {
case 0:
return (false);
case 1:
return (addr == 0 || (cow & MAP_NO_HINT) != 0);
case 2:
default:
return (true);
}
}
static long aslr_restarts;
SYSCTL_LONG(_vm, OID_AUTO, aslr_restarts, CTLFLAG_RD,
&aslr_restarts, 0,
"Number of aslr failures");
/*
* Searches for the specified amount of free space in the given map with the
* specified alignment. Performs an address-ordered, first-fit search from
* the given address "*addr", with an optional upper bound "max_addr". If the
* parameter "alignment" is zero, then the alignment is computed from the
* given (object, offset) pair so as to enable the greatest possible use of
* superpage mappings. Returns KERN_SUCCESS and the address of the free space
* in "*addr" if successful. Otherwise, returns KERN_NO_SPACE.
*
* The map must be locked. Initially, there must be at least "length" bytes
* of free space at the given address.
*/
static int
vm_map_alignspace(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
vm_offset_t *addr, vm_size_t length, vm_offset_t max_addr,
vm_offset_t alignment)
{
vm_offset_t aligned_addr, free_addr;
VM_MAP_ASSERT_LOCKED(map);
free_addr = *addr;
KASSERT(free_addr == vm_map_findspace(map, free_addr, length),
("caller failed to provide space %#jx at address %p",
(uintmax_t)length, (void *)free_addr));
for (;;) {
/*
* At the start of every iteration, the free space at address
* "*addr" is at least "length" bytes.
*/
if (alignment == 0)
pmap_align_superpage(object, offset, addr, length);
else
*addr = roundup2(*addr, alignment);
aligned_addr = *addr;
if (aligned_addr == free_addr) {
/*
* Alignment did not change "*addr", so "*addr" must
* still provide sufficient free space.
*/
return (KERN_SUCCESS);
}
/*
* Test for address wrap on "*addr". A wrapped "*addr" could
* be a valid address, in which case vm_map_findspace() cannot
* be relied upon to fail.
*/
if (aligned_addr < free_addr)
return (KERN_NO_SPACE);
*addr = vm_map_findspace(map, aligned_addr, length);
if (*addr + length > vm_map_max(map) ||
(max_addr != 0 && *addr + length > max_addr))
return (KERN_NO_SPACE);
free_addr = *addr;
if (free_addr == aligned_addr) {
/*
* If a successful call to vm_map_findspace() did not
* change "*addr", then "*addr" must still be aligned
* and provide sufficient free space.
*/
return (KERN_SUCCESS);
}
}
}
int
vm_map_find_aligned(vm_map_t map, vm_offset_t *addr, vm_size_t length,
vm_offset_t max_addr, vm_offset_t alignment)
{
/* XXXKIB ASLR eh ? */
*addr = vm_map_findspace(map, *addr, length);
if (*addr + length > vm_map_max(map) ||
(max_addr != 0 && *addr + length > max_addr))
return (KERN_NO_SPACE);
return (vm_map_alignspace(map, NULL, 0, addr, length, max_addr,
alignment));
}
/*
* vm_map_find finds an unallocated region in the target address
* map with the given length. The search is defined to be
* first-fit from the specified address; the region found is
* returned in the same parameter.
*
* If object is non-NULL, ref count must be bumped by caller
* prior to making call to account for the new entry.
*/
int
vm_map_find(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
vm_offset_t *addr, /* IN/OUT */
vm_size_t length, vm_offset_t max_addr, int find_space,
vm_prot_t prot, vm_prot_t max, int cow)
{
vm_offset_t alignment, curr_min_addr, min_addr;
int gap, pidx, rv, try;
bool cluster, en_aslr, update_anon;
KASSERT((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) == 0 ||
object == NULL,
("vm_map_find: non-NULL backing object for stack"));
MPASS((cow & MAP_REMAP) == 0 || (find_space == VMFS_NO_SPACE &&
(cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) == 0));
if (find_space == VMFS_OPTIMAL_SPACE && (object == NULL ||
(object->flags & OBJ_COLORED) == 0))
find_space = VMFS_ANY_SPACE;
if (find_space >> 8 != 0) {
KASSERT((find_space & 0xff) == 0, ("bad VMFS flags"));
alignment = (vm_offset_t)1 << (find_space >> 8);
} else
alignment = 0;
en_aslr = (map->flags & MAP_ASLR) != 0;
update_anon = cluster = clustering_anon_allowed(*addr, cow) &&
(map->flags & MAP_IS_SUB_MAP) == 0 && max_addr == 0 &&
find_space != VMFS_NO_SPACE && object == NULL &&
(cow & (MAP_INHERIT_SHARE | MAP_STACK_GROWS_UP |
MAP_STACK_GROWS_DOWN)) == 0 && prot != PROT_NONE;
curr_min_addr = min_addr = *addr;
if (en_aslr && min_addr == 0 && !cluster &&
find_space != VMFS_NO_SPACE &&
(map->flags & MAP_ASLR_IGNSTART) != 0)
curr_min_addr = min_addr = vm_map_min(map);
try = 0;
vm_map_lock(map);
if (cluster) {
curr_min_addr = map->anon_loc;
if (curr_min_addr == 0)
cluster = false;
}
if (find_space != VMFS_NO_SPACE) {
KASSERT(find_space == VMFS_ANY_SPACE ||
find_space == VMFS_OPTIMAL_SPACE ||
find_space == VMFS_SUPER_SPACE ||
alignment != 0, ("unexpected VMFS flag"));
again:
/*
* When creating an anonymous mapping, try clustering
* with an existing anonymous mapping first.
*
* We make up to two attempts to find address space
* for a given find_space value. The first attempt may
* apply randomization or may cluster with an existing
* anonymous mapping. If this first attempt fails,
* perform a first-fit search of the available address
* space.
*
* If all tries failed, and find_space is
* VMFS_OPTIMAL_SPACE, fallback to VMFS_ANY_SPACE.
* Again enable clustering and randomization.
*/
try++;
MPASS(try <= 2);
if (try == 2) {
/*
* Second try: we failed either to find a
* suitable region for randomizing the
* allocation, or to cluster with an existing
* mapping. Retry with free run.
*/
curr_min_addr = (map->flags & MAP_ASLR_IGNSTART) != 0 ?
vm_map_min(map) : min_addr;
atomic_add_long(&aslr_restarts, 1);
}
if (try == 1 && en_aslr && !cluster) {
/*
* Find space for allocation, including
* gap needed for later randomization.
*/
pidx = MAXPAGESIZES > 1 && pagesizes[1] != 0 &&
(find_space == VMFS_SUPER_SPACE || find_space ==
VMFS_OPTIMAL_SPACE) ? 1 : 0;
gap = vm_map_max(map) > MAP_32BIT_MAX_ADDR &&
(max_addr == 0 || max_addr > MAP_32BIT_MAX_ADDR) ?
aslr_pages_rnd_64[pidx] : aslr_pages_rnd_32[pidx];
*addr = vm_map_findspace(map, curr_min_addr,
length + gap * pagesizes[pidx]);
if (*addr + length + gap * pagesizes[pidx] >
vm_map_max(map))
goto again;
/* And randomize the start address. */
*addr += (arc4random() % gap) * pagesizes[pidx];
if (max_addr != 0 && *addr + length > max_addr)
goto again;
} else {
*addr = vm_map_findspace(map, curr_min_addr, length);
if (*addr + length > vm_map_max(map) ||
(max_addr != 0 && *addr + length > max_addr)) {
if (cluster) {
cluster = false;
MPASS(try == 1);
goto again;
}
rv = KERN_NO_SPACE;
goto done;
}
}
if (find_space != VMFS_ANY_SPACE &&
(rv = vm_map_alignspace(map, object, offset, addr, length,
max_addr, alignment)) != KERN_SUCCESS) {
if (find_space == VMFS_OPTIMAL_SPACE) {
find_space = VMFS_ANY_SPACE;
curr_min_addr = min_addr;
cluster = update_anon;
try = 0;
goto again;
}
goto done;
}
} else if ((cow & MAP_REMAP) != 0) {
if (!vm_map_range_valid(map, *addr, *addr + length)) {
rv = KERN_INVALID_ADDRESS;
goto done;
}
rv = vm_map_delete(map, *addr, *addr + length);
if (rv != KERN_SUCCESS)
goto done;
}
if ((cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP)) != 0) {
rv = vm_map_stack_locked(map, *addr, length, sgrowsiz, prot,
max, cow);
} else {
rv = vm_map_insert(map, object, offset, *addr, *addr + length,
prot, max, cow);
}
/*
* Update the starting address for clustered anonymous memory mappings
* if a starting address was not previously defined or an ASLR restart
* placed an anonymous memory mapping at a lower address.
*/
if (update_anon && rv == KERN_SUCCESS && (map->anon_loc == 0 ||
*addr < map->anon_loc))
map->anon_loc = *addr;
done:
vm_map_unlock(map);
return (rv);
}
/*
* vm_map_find_min() is a variant of vm_map_find() that takes an
* additional parameter ("default_addr") and treats the given address
* ("*addr") differently. Specifically, it treats "*addr" as a hint
* and not as the minimum address where the mapping is created.
*
* This function works in two phases. First, it tries to
* allocate above the hint. If that fails and the hint is
* greater than "default_addr", it performs a second pass, replacing
* the hint with "default_addr" as the minimum address for the
* allocation.
*/
int
vm_map_find_min(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
vm_offset_t *addr, vm_size_t length, vm_offset_t default_addr,
vm_offset_t max_addr, int find_space, vm_prot_t prot, vm_prot_t max,
int cow)
{
vm_offset_t hint;
int rv;
hint = *addr;
if (hint == 0) {
cow |= MAP_NO_HINT;
*addr = hint = default_addr;
}
for (;;) {
rv = vm_map_find(map, object, offset, addr, length, max_addr,
find_space, prot, max, cow);
if (rv == KERN_SUCCESS || default_addr >= hint)
return (rv);
*addr = hint = default_addr;
}
}
/*
* A map entry with any of the following flags set must not be merged with
* another entry.
*/
#define MAP_ENTRY_NOMERGE_MASK (MAP_ENTRY_GROWS_DOWN | MAP_ENTRY_GROWS_UP | \
MAP_ENTRY_IN_TRANSITION | MAP_ENTRY_IS_SUB_MAP | MAP_ENTRY_VN_EXEC | \
MAP_ENTRY_STACK_GAP_UP | MAP_ENTRY_STACK_GAP_DN)
static bool
vm_map_mergeable_neighbors(vm_map_entry_t prev, vm_map_entry_t entry)
{
KASSERT((prev->eflags & MAP_ENTRY_NOMERGE_MASK) == 0 ||
(entry->eflags & MAP_ENTRY_NOMERGE_MASK) == 0,
("vm_map_mergeable_neighbors: neither %p nor %p are mergeable",
prev, entry));
return (prev->end == entry->start &&
prev->object.vm_object == entry->object.vm_object &&
(prev->object.vm_object == NULL ||
prev->offset + (prev->end - prev->start) == entry->offset) &&
prev->eflags == entry->eflags &&
prev->protection == entry->protection &&
prev->max_protection == entry->max_protection &&
prev->inheritance == entry->inheritance &&
prev->wired_count == entry->wired_count &&
prev->cred == entry->cred);
}
static void
vm_map_merged_neighbor_dispose(vm_map_t map, vm_map_entry_t entry)
{
/*
* If the backing object is a vnode object, vm_object_deallocate()
* calls vrele(). However, vrele() does not lock the vnode because
* the vnode has additional references. Thus, the map lock can be
* kept without causing a lock-order reversal with the vnode lock.
*
* Since we count the number of virtual page mappings in
* object->un_pager.vnp.writemappings, the writemappings value
* should not be adjusted when the entry is disposed of.
*/
if (entry->object.vm_object != NULL)
vm_object_deallocate(entry->object.vm_object);
if (entry->cred != NULL)
crfree(entry->cred);
vm_map_entry_dispose(map, entry);
}
/*
* vm_map_try_merge_entries:
*
* Compare two map entries that represent consecutive ranges. If
* the entries can be merged, expand the range of the second to
* cover the range of the first and delete the first. Then return
* the map entry that includes the first range.
*
* The map must be locked.
*/
vm_map_entry_t
vm_map_try_merge_entries(vm_map_t map, vm_map_entry_t prev_entry,
vm_map_entry_t entry)
{
VM_MAP_ASSERT_LOCKED(map);
if ((entry->eflags & MAP_ENTRY_NOMERGE_MASK) == 0 &&
vm_map_mergeable_neighbors(prev_entry, entry)) {
vm_map_entry_unlink(map, prev_entry, UNLINK_MERGE_NEXT);
vm_map_merged_neighbor_dispose(map, prev_entry);
return (entry);
}
return (prev_entry);
}
/*
* vm_map_entry_back:
*
* Allocate an object to back a map entry.
*/
static inline void
vm_map_entry_back(vm_map_entry_t entry)
{
vm_object_t object;
KASSERT(entry->object.vm_object == NULL,
("map entry %p has backing object", entry));
KASSERT((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0,
("map entry %p is a submap", entry));
object = vm_object_allocate_anon(atop(entry->end - entry->start), NULL,
entry->cred, entry->end - entry->start);
entry->object.vm_object = object;
entry->offset = 0;
entry->cred = NULL;
}
/*
* vm_map_entry_charge_object
*
* If there is no object backing this entry, create one. Otherwise, if
* the entry has cred, give it to the backing object.
*/
static inline void
vm_map_entry_charge_object(vm_map_t map, vm_map_entry_t entry)
{
VM_MAP_ASSERT_LOCKED(map);
KASSERT((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0,
("map entry %p is a submap", entry));
if (entry->object.vm_object == NULL && !map->system_map &&
(entry->eflags & MAP_ENTRY_GUARD) == 0)
vm_map_entry_back(entry);
else if (entry->object.vm_object != NULL &&
((entry->eflags & MAP_ENTRY_NEEDS_COPY) == 0) &&
entry->cred != NULL) {
VM_OBJECT_WLOCK(entry->object.vm_object);
KASSERT(entry->object.vm_object->cred == NULL,
("OVERCOMMIT: %s: both cred e %p", __func__, entry));
entry->object.vm_object->cred = entry->cred;
entry->object.vm_object->charge = entry->end - entry->start;
VM_OBJECT_WUNLOCK(entry->object.vm_object);
entry->cred = NULL;
}
}
/*
* vm_map_entry_clone
*
* Create a duplicate map entry for clipping.
*/
static vm_map_entry_t
vm_map_entry_clone(vm_map_t map, vm_map_entry_t entry)
{
vm_map_entry_t new_entry;
VM_MAP_ASSERT_LOCKED(map);
/*
* Create a backing object now, if none exists, so that more individual
* objects won't be created after the map entry is split.
*/
vm_map_entry_charge_object(map, entry);
/* Clone the entry. */
new_entry = vm_map_entry_create(map);
*new_entry = *entry;
if (new_entry->cred != NULL)
crhold(entry->cred);
if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) {
vm_object_reference(new_entry->object.vm_object);
vm_map_entry_set_vnode_text(new_entry, true);
/*
* The object->un_pager.vnp.writemappings for the object of
* MAP_ENTRY_WRITECNT type entry shall be kept as is here. The
* virtual pages are re-distributed among the clipped entries,
* so the sum is left the same.
*/
}
return (new_entry);
}
/*
* vm_map_clip_start: [ internal use only ]
*
* Asserts that the given entry begins at or after
* the specified address; if necessary,
* it splits the entry into two.
*/
static int
vm_map_clip_start(vm_map_t map, vm_map_entry_t entry, vm_offset_t startaddr)
{
vm_map_entry_t new_entry;
int bdry_idx;
if (!map->system_map)
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
"%s: map %p entry %p start 0x%jx", __func__, map, entry,
(uintmax_t)startaddr);
if (startaddr <= entry->start)
return (KERN_SUCCESS);
VM_MAP_ASSERT_LOCKED(map);
KASSERT(entry->end > startaddr && entry->start < startaddr,
("%s: invalid clip of entry %p", __func__, entry));
bdry_idx = MAP_ENTRY_SPLIT_BOUNDARY_INDEX(entry);
if (bdry_idx != 0) {
if ((startaddr & (pagesizes[bdry_idx] - 1)) != 0)
return (KERN_INVALID_ARGUMENT);
}
new_entry = vm_map_entry_clone(map, entry);
/*
* Split off the front portion. Insert the new entry BEFORE this one,
* so that this entry has the specified starting address.
*/
new_entry->end = startaddr;
vm_map_entry_link(map, new_entry);
return (KERN_SUCCESS);
}
/*
* vm_map_lookup_clip_start:
*
* Find the entry at or just after 'start', and clip it if 'start' is in
* the interior of the entry. Return entry after 'start', and in
* prev_entry set the entry before 'start'.
*/
static int
vm_map_lookup_clip_start(vm_map_t map, vm_offset_t start,
vm_map_entry_t *res_entry, vm_map_entry_t *prev_entry)
{
vm_map_entry_t entry;
int rv;
if (!map->system_map)
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
"%s: map %p start 0x%jx prev %p", __func__, map,
(uintmax_t)start, prev_entry);
if (vm_map_lookup_entry(map, start, prev_entry)) {
entry = *prev_entry;
rv = vm_map_clip_start(map, entry, start);
if (rv != KERN_SUCCESS)
return (rv);
*prev_entry = vm_map_entry_pred(entry);
} else
entry = vm_map_entry_succ(*prev_entry);
*res_entry = entry;
return (KERN_SUCCESS);
}
/*
* vm_map_clip_end: [ internal use only ]
*
* Asserts that the given entry ends at or before
* the specified address; if necessary,
* it splits the entry into two.
*/
static int
vm_map_clip_end(vm_map_t map, vm_map_entry_t entry, vm_offset_t endaddr)
{
vm_map_entry_t new_entry;
int bdry_idx;
if (!map->system_map)
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
"%s: map %p entry %p end 0x%jx", __func__, map, entry,
(uintmax_t)endaddr);
if (endaddr >= entry->end)
return (KERN_SUCCESS);
VM_MAP_ASSERT_LOCKED(map);
KASSERT(entry->start < endaddr && entry->end > endaddr,
("%s: invalid clip of entry %p", __func__, entry));
bdry_idx = MAP_ENTRY_SPLIT_BOUNDARY_INDEX(entry);
if (bdry_idx != 0) {
if ((endaddr & (pagesizes[bdry_idx] - 1)) != 0)
return (KERN_INVALID_ARGUMENT);
}
new_entry = vm_map_entry_clone(map, entry);
/*
* Split off the back portion. Insert the new entry AFTER this one,
* so that this entry has the specified ending address.
*/
new_entry->start = endaddr;
vm_map_entry_link(map, new_entry);
return (KERN_SUCCESS);
}
/*
* vm_map_submap: [ kernel use only ]
*
* Mark the given range as handled by a subordinate map.
*
* This range must have been created with vm_map_find,
* and no other operations may have been performed on this
* range prior to calling vm_map_submap.
*
* Only a limited number of operations can be performed
* within this rage after calling vm_map_submap:
* vm_fault
* [Don't try vm_map_copy!]
*
* To remove a submapping, one must first remove the
* range from the superior map, and then destroy the
* submap (if desired). [Better yet, don't try it.]
*/
int
vm_map_submap(
vm_map_t map,
vm_offset_t start,
vm_offset_t end,
vm_map_t submap)
{
vm_map_entry_t entry;
int result;
result = KERN_INVALID_ARGUMENT;
vm_map_lock(submap);
submap->flags |= MAP_IS_SUB_MAP;
vm_map_unlock(submap);
vm_map_lock(map);
VM_MAP_RANGE_CHECK(map, start, end);
if (vm_map_lookup_entry(map, start, &entry) && entry->end >= end &&
(entry->eflags & MAP_ENTRY_COW) == 0 &&
entry->object.vm_object == NULL) {
result = vm_map_clip_start(map, entry, start);
if (result != KERN_SUCCESS)
goto unlock;
result = vm_map_clip_end(map, entry, end);
if (result != KERN_SUCCESS)
goto unlock;
entry->object.sub_map = submap;
entry->eflags |= MAP_ENTRY_IS_SUB_MAP;
result = KERN_SUCCESS;
}
unlock:
vm_map_unlock(map);
if (result != KERN_SUCCESS) {
vm_map_lock(submap);
submap->flags &= ~MAP_IS_SUB_MAP;
vm_map_unlock(submap);
}
return (result);
}
/*
* The maximum number of pages to map if MAP_PREFAULT_PARTIAL is specified
*/
#define MAX_INIT_PT 96
/*
* vm_map_pmap_enter:
*
* Preload the specified map's pmap with mappings to the specified
* object's memory-resident pages. No further physical pages are
* allocated, and no further virtual pages are retrieved from secondary
* storage. If the specified flags include MAP_PREFAULT_PARTIAL, then a
* limited number of page mappings are created at the low-end of the
* specified address range. (For this purpose, a superpage mapping
* counts as one page mapping.) Otherwise, all resident pages within
* the specified address range are mapped.
*/
static void
vm_map_pmap_enter(vm_map_t map, vm_offset_t addr, vm_prot_t prot,
vm_object_t object, vm_pindex_t pindex, vm_size_t size, int flags)
{
vm_offset_t start;
vm_page_t p, p_start;
vm_pindex_t mask, psize, threshold, tmpidx;
if ((prot & (VM_PROT_READ | VM_PROT_EXECUTE)) == 0 || object == NULL)
return;
if (object->type == OBJT_DEVICE || object->type == OBJT_SG) {
VM_OBJECT_WLOCK(object);
if (object->type == OBJT_DEVICE || object->type == OBJT_SG) {
pmap_object_init_pt(map->pmap, addr, object, pindex,
size);
VM_OBJECT_WUNLOCK(object);
return;
}
VM_OBJECT_LOCK_DOWNGRADE(object);
} else
VM_OBJECT_RLOCK(object);
psize = atop(size);
if (psize + pindex > object->size) {
if (pindex >= object->size) {
VM_OBJECT_RUNLOCK(object);
return;
}
psize = object->size - pindex;
}
start = 0;
p_start = NULL;
threshold = MAX_INIT_PT;
p = vm_page_find_least(object, pindex);
/*
* Assert: the variable p is either (1) the page with the
* least pindex greater than or equal to the parameter pindex
* or (2) NULL.
*/
for (;
p != NULL && (tmpidx = p->pindex - pindex) < psize;
p = TAILQ_NEXT(p, listq)) {
/*
* don't allow an madvise to blow away our really
* free pages allocating pv entries.
*/
if (((flags & MAP_PREFAULT_MADVISE) != 0 &&
vm_page_count_severe()) ||
((flags & MAP_PREFAULT_PARTIAL) != 0 &&
tmpidx >= threshold)) {
psize = tmpidx;
break;
}
if (vm_page_all_valid(p)) {
if (p_start == NULL) {
start = addr + ptoa(tmpidx);
p_start = p;
}
/* Jump ahead if a superpage mapping is possible. */
if (p->psind > 0 && ((addr + ptoa(tmpidx)) &
(pagesizes[p->psind] - 1)) == 0) {
mask = atop(pagesizes[p->psind]) - 1;
if (tmpidx + mask < psize &&
vm_page_ps_test(p, PS_ALL_VALID, NULL)) {
p += mask;
threshold += mask;
}
}
} else if (p_start != NULL) {
pmap_enter_object(map->pmap, start, addr +
ptoa(tmpidx), p_start, prot);
p_start = NULL;
}
}
if (p_start != NULL)
pmap_enter_object(map->pmap, start, addr + ptoa(psize),
p_start, prot);
VM_OBJECT_RUNLOCK(object);
}
static void
vm_map_protect_guard(vm_map_entry_t entry, vm_prot_t new_prot,
vm_prot_t new_maxprot, int flags)
{
vm_prot_t old_prot;
MPASS((entry->eflags & MAP_ENTRY_GUARD) != 0);
if ((entry->eflags & (MAP_ENTRY_STACK_GAP_UP |
MAP_ENTRY_STACK_GAP_DN)) == 0)
return;
old_prot = PROT_EXTRACT(entry->offset);
if ((flags & VM_MAP_PROTECT_SET_MAXPROT) != 0) {
entry->offset = PROT_MAX(new_maxprot) |
(new_maxprot & old_prot);
}
if ((flags & VM_MAP_PROTECT_SET_PROT) != 0) {
entry->offset = new_prot | PROT_MAX(
PROT_MAX_EXTRACT(entry->offset));
}
}
/*
* vm_map_protect:
*
* Sets the protection and/or the maximum protection of the
* specified address region in the target map.
*/
int
vm_map_protect(vm_map_t map, vm_offset_t start, vm_offset_t end,
vm_prot_t new_prot, vm_prot_t new_maxprot, int flags)
{
vm_map_entry_t entry, first_entry, in_tran, prev_entry;
vm_object_t obj;
struct ucred *cred;
vm_offset_t orig_start;
vm_prot_t check_prot, max_prot, old_prot;
int rv;
if (start == end)
return (KERN_SUCCESS);
if (CONTAINS_BITS(flags, VM_MAP_PROTECT_SET_PROT |
VM_MAP_PROTECT_SET_MAXPROT) &&
!CONTAINS_BITS(new_maxprot, new_prot))
return (KERN_OUT_OF_BOUNDS);
orig_start = start;
again:
in_tran = NULL;
start = orig_start;
vm_map_lock(map);
if ((map->flags & MAP_WXORX) != 0 &&
(flags & VM_MAP_PROTECT_SET_PROT) != 0 &&
CONTAINS_BITS(new_prot, VM_PROT_WRITE | VM_PROT_EXECUTE)) {
vm_map_unlock(map);
return (KERN_PROTECTION_FAILURE);
}
/*
* Ensure that we are not concurrently wiring pages. vm_map_wire() may
* need to fault pages into the map and will drop the map lock while
* doing so, and the VM object may end up in an inconsistent state if we
* update the protection on the map entry in between faults.
*/
vm_map_wait_busy(map);
VM_MAP_RANGE_CHECK(map, start, end);
if (!vm_map_lookup_entry(map, start, &first_entry))
first_entry = vm_map_entry_succ(first_entry);
if ((flags & VM_MAP_PROTECT_GROWSDOWN) != 0 &&
(first_entry->eflags & MAP_ENTRY_GROWS_DOWN) != 0) {
/*
* Handle Linux's PROT_GROWSDOWN flag.
* It means that protection is applied down to the
* whole stack, including the specified range of the
* mapped region, and the grow down region (AKA
* guard).
*/
while (!CONTAINS_BITS(first_entry->eflags,
MAP_ENTRY_GUARD | MAP_ENTRY_STACK_GAP_DN) &&
first_entry != vm_map_entry_first(map))
first_entry = vm_map_entry_pred(first_entry);
start = first_entry->start;
}
/*
* Make a first pass to check for protection violations.
*/
check_prot = 0;
if ((flags & VM_MAP_PROTECT_SET_PROT) != 0)
check_prot |= new_prot;
if ((flags & VM_MAP_PROTECT_SET_MAXPROT) != 0)
check_prot |= new_maxprot;
for (entry = first_entry; entry->start < end;
entry = vm_map_entry_succ(entry)) {
if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0) {
vm_map_unlock(map);
return (KERN_INVALID_ARGUMENT);
}
if ((entry->eflags & (MAP_ENTRY_GUARD |
MAP_ENTRY_STACK_GAP_DN | MAP_ENTRY_STACK_GAP_UP)) ==
MAP_ENTRY_GUARD)
continue;
max_prot = (entry->eflags & (MAP_ENTRY_STACK_GAP_DN |
MAP_ENTRY_STACK_GAP_UP)) != 0 ?
PROT_MAX_EXTRACT(entry->offset) : entry->max_protection;
if (!CONTAINS_BITS(max_prot, check_prot)) {
vm_map_unlock(map);
return (KERN_PROTECTION_FAILURE);
}
if ((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0)
in_tran = entry;
}
/*
* Postpone the operation until all in-transition map entries have
* stabilized. An in-transition entry might already have its pages
* wired and wired_count incremented, but not yet have its
* MAP_ENTRY_USER_WIRED flag set. In which case, we would fail to call
* vm_fault_copy_entry() in the final loop below.
*/
if (in_tran != NULL) {
in_tran->eflags |= MAP_ENTRY_NEEDS_WAKEUP;
vm_map_unlock_and_wait(map, 0);
goto again;
}
/*
* Before changing the protections, try to reserve swap space for any
* private (i.e., copy-on-write) mappings that are transitioning from
* read-only to read/write access. If a reservation fails, break out
* of this loop early and let the next loop simplify the entries, since
* some may now be mergeable.
*/
rv = vm_map_clip_start(map, first_entry, start);
if (rv != KERN_SUCCESS) {
vm_map_unlock(map);
return (rv);
}
for (entry = first_entry; entry->start < end;
entry = vm_map_entry_succ(entry)) {
rv = vm_map_clip_end(map, entry, end);
if (rv != KERN_SUCCESS) {
vm_map_unlock(map);
return (rv);
}
if ((flags & VM_MAP_PROTECT_SET_PROT) == 0 ||
((new_prot & ~entry->protection) & VM_PROT_WRITE) == 0 ||
ENTRY_CHARGED(entry) ||
(entry->eflags & MAP_ENTRY_GUARD) != 0)
continue;
cred = curthread->td_ucred;
obj = entry->object.vm_object;
if (obj == NULL ||
(entry->eflags & MAP_ENTRY_NEEDS_COPY) != 0) {
if (!swap_reserve(entry->end - entry->start)) {
rv = KERN_RESOURCE_SHORTAGE;
end = entry->end;
break;
}
crhold(cred);
entry->cred = cred;
continue;
}
VM_OBJECT_WLOCK(obj);
if ((obj->flags & OBJ_SWAP) == 0) {
VM_OBJECT_WUNLOCK(obj);
continue;
}
/*
* Charge for the whole object allocation now, since
* we cannot distinguish between non-charged and
* charged clipped mapping of the same object later.
*/
KASSERT(obj->charge == 0,
("vm_map_protect: object %p overcharged (entry %p)",
obj, entry));
if (!swap_reserve(ptoa(obj->size))) {
VM_OBJECT_WUNLOCK(obj);
rv = KERN_RESOURCE_SHORTAGE;
end = entry->end;
break;
}
crhold(cred);
obj->cred = cred;
obj->charge = ptoa(obj->size);
VM_OBJECT_WUNLOCK(obj);
}
/*
* If enough swap space was available, go back and fix up protections.
* Otherwise, just simplify entries, since some may have been modified.
* [Note that clipping is not necessary the second time.]
*/
for (prev_entry = vm_map_entry_pred(first_entry), entry = first_entry;
entry->start < end;
vm_map_try_merge_entries(map, prev_entry, entry),
prev_entry = entry, entry = vm_map_entry_succ(entry)) {
if (rv != KERN_SUCCESS)
continue;
if ((entry->eflags & MAP_ENTRY_GUARD) != 0) {
vm_map_protect_guard(entry, new_prot, new_maxprot,
flags);
continue;
}
old_prot = entry->protection;
if ((flags & VM_MAP_PROTECT_SET_MAXPROT) != 0) {
entry->max_protection = new_maxprot;
entry->protection = new_maxprot & old_prot;
}
if ((flags & VM_MAP_PROTECT_SET_PROT) != 0)
entry->protection = new_prot;
/*
* For user wired map entries, the normal lazy evaluation of
* write access upgrades through soft page faults is
* undesirable. Instead, immediately copy any pages that are
* copy-on-write and enable write access in the physical map.
*/
if ((entry->eflags & MAP_ENTRY_USER_WIRED) != 0 &&
(entry->protection & VM_PROT_WRITE) != 0 &&
(old_prot & VM_PROT_WRITE) == 0)
vm_fault_copy_entry(map, map, entry, entry, NULL);
/*
* When restricting access, update the physical map. Worry
* about copy-on-write here.
*/
if ((old_prot & ~entry->protection) != 0) {
#define MASK(entry) (((entry)->eflags & MAP_ENTRY_COW) ? ~VM_PROT_WRITE : \
VM_PROT_ALL)
pmap_protect(map->pmap, entry->start,
entry->end,
entry->protection & MASK(entry));
#undef MASK
}
}
vm_map_try_merge_entries(map, prev_entry, entry);
vm_map_unlock(map);
return (rv);
}
/*
* vm_map_madvise:
*
* This routine traverses a processes map handling the madvise
* system call. Advisories are classified as either those effecting
* the vm_map_entry structure, or those effecting the underlying
* objects.
*/
int
vm_map_madvise(
vm_map_t map,
vm_offset_t start,
vm_offset_t end,
int behav)
{
vm_map_entry_t entry, prev_entry;
int rv;
bool modify_map;
/*
* Some madvise calls directly modify the vm_map_entry, in which case
* we need to use an exclusive lock on the map and we need to perform
* various clipping operations. Otherwise we only need a read-lock
* on the map.
*/
switch(behav) {
case MADV_NORMAL:
case MADV_SEQUENTIAL:
case MADV_RANDOM:
case MADV_NOSYNC:
case MADV_AUTOSYNC:
case MADV_NOCORE:
case MADV_CORE:
if (start == end)
return (0);
modify_map = true;
vm_map_lock(map);
break;
case MADV_WILLNEED:
case MADV_DONTNEED:
case MADV_FREE:
if (start == end)
return (0);
modify_map = false;
vm_map_lock_read(map);
break;
default:
return (EINVAL);
}
/*
* Locate starting entry and clip if necessary.
*/
VM_MAP_RANGE_CHECK(map, start, end);
if (modify_map) {
/*
* madvise behaviors that are implemented in the vm_map_entry.
*
* We clip the vm_map_entry so that behavioral changes are
* limited to the specified address range.
*/
rv = vm_map_lookup_clip_start(map, start, &entry, &prev_entry);
if (rv != KERN_SUCCESS) {
vm_map_unlock(map);
return (vm_mmap_to_errno(rv));
}
for (; entry->start < end; prev_entry = entry,
entry = vm_map_entry_succ(entry)) {
if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0)
continue;
rv = vm_map_clip_end(map, entry, end);
if (rv != KERN_SUCCESS) {
vm_map_unlock(map);
return (vm_mmap_to_errno(rv));
}
switch (behav) {
case MADV_NORMAL:
vm_map_entry_set_behavior(entry,
MAP_ENTRY_BEHAV_NORMAL);
break;
case MADV_SEQUENTIAL:
vm_map_entry_set_behavior(entry,
MAP_ENTRY_BEHAV_SEQUENTIAL);
break;
case MADV_RANDOM:
vm_map_entry_set_behavior(entry,
MAP_ENTRY_BEHAV_RANDOM);
break;
case MADV_NOSYNC:
entry->eflags |= MAP_ENTRY_NOSYNC;
break;
case MADV_AUTOSYNC:
entry->eflags &= ~MAP_ENTRY_NOSYNC;
break;
case MADV_NOCORE:
entry->eflags |= MAP_ENTRY_NOCOREDUMP;
break;
case MADV_CORE:
entry->eflags &= ~MAP_ENTRY_NOCOREDUMP;
break;
default:
break;
}
vm_map_try_merge_entries(map, prev_entry, entry);
}
vm_map_try_merge_entries(map, prev_entry, entry);
vm_map_unlock(map);
} else {
vm_pindex_t pstart, pend;
/*
* madvise behaviors that are implemented in the underlying
* vm_object.
*
* Since we don't clip the vm_map_entry, we have to clip
* the vm_object pindex and count.
*/
if (!vm_map_lookup_entry(map, start, &entry))
entry = vm_map_entry_succ(entry);
for (; entry->start < end;
entry = vm_map_entry_succ(entry)) {
vm_offset_t useEnd, useStart;
if ((entry->eflags & (MAP_ENTRY_IS_SUB_MAP |
MAP_ENTRY_GUARD)) != 0)
continue;
/*
* MADV_FREE would otherwise rewind time to
* the creation of the shadow object. Because
* we hold the VM map read-locked, neither the
* entry's object nor the presence of a
* backing object can change.
*/
if (behav == MADV_FREE &&
entry->object.vm_object != NULL &&
entry->object.vm_object->backing_object != NULL)
continue;
pstart = OFF_TO_IDX(entry->offset);
pend = pstart + atop(entry->end - entry->start);
useStart = entry->start;
useEnd = entry->end;
if (entry->start < start) {
pstart += atop(start - entry->start);
useStart = start;
}
if (entry->end > end) {
pend -= atop(entry->end - end);
useEnd = end;
}
if (pstart >= pend)
continue;
/*
* Perform the pmap_advise() before clearing
* PGA_REFERENCED in vm_page_advise(). Otherwise, a
* concurrent pmap operation, such as pmap_remove(),
* could clear a reference in the pmap and set
* PGA_REFERENCED on the page before the pmap_advise()
* had completed. Consequently, the page would appear
* referenced based upon an old reference that
* occurred before this pmap_advise() ran.
*/
if (behav == MADV_DONTNEED || behav == MADV_FREE)
pmap_advise(map->pmap, useStart, useEnd,
behav);
vm_object_madvise(entry->object.vm_object, pstart,
pend, behav);
/*
* Pre-populate paging structures in the
* WILLNEED case. For wired entries, the
* paging structures are already populated.
*/
if (behav == MADV_WILLNEED &&
entry->wired_count == 0) {
vm_map_pmap_enter(map,
useStart,
entry->protection,
entry->object.vm_object,
pstart,
ptoa(pend - pstart),
MAP_PREFAULT_MADVISE
);
}
}
vm_map_unlock_read(map);
}
return (0);
}
/*
* vm_map_inherit:
*
* Sets the inheritance of the specified address
* range in the target map. Inheritance
* affects how the map will be shared with
* child maps at the time of vmspace_fork.
*/
int
vm_map_inherit(vm_map_t map, vm_offset_t start, vm_offset_t end,
vm_inherit_t new_inheritance)
{
vm_map_entry_t entry, lentry, prev_entry, start_entry;
int rv;
switch (new_inheritance) {
case VM_INHERIT_NONE:
case VM_INHERIT_COPY:
case VM_INHERIT_SHARE:
case VM_INHERIT_ZERO:
break;
default:
return (KERN_INVALID_ARGUMENT);
}
if (start == end)
return (KERN_SUCCESS);
vm_map_lock(map);
VM_MAP_RANGE_CHECK(map, start, end);
rv = vm_map_lookup_clip_start(map, start, &start_entry, &prev_entry);
if (rv != KERN_SUCCESS)
goto unlock;
if (vm_map_lookup_entry(map, end - 1, &lentry)) {
rv = vm_map_clip_end(map, lentry, end);
if (rv != KERN_SUCCESS)
goto unlock;
}
if (new_inheritance == VM_INHERIT_COPY) {
for (entry = start_entry; entry->start < end;
prev_entry = entry, entry = vm_map_entry_succ(entry)) {
if ((entry->eflags & MAP_ENTRY_SPLIT_BOUNDARY_MASK)
!= 0) {
rv = KERN_INVALID_ARGUMENT;
goto unlock;
}
}
}
for (entry = start_entry; entry->start < end; prev_entry = entry,
entry = vm_map_entry_succ(entry)) {
KASSERT(entry->end <= end, ("non-clipped entry %p end %jx %jx",
entry, (uintmax_t)entry->end, (uintmax_t)end));
if ((entry->eflags & MAP_ENTRY_GUARD) == 0 ||
new_inheritance != VM_INHERIT_ZERO)
entry->inheritance = new_inheritance;
vm_map_try_merge_entries(map, prev_entry, entry);
}
vm_map_try_merge_entries(map, prev_entry, entry);
unlock:
vm_map_unlock(map);
return (rv);
}
/*
* vm_map_entry_in_transition:
*
* Release the map lock, and sleep until the entry is no longer in
* transition. Awake and acquire the map lock. If the map changed while
* another held the lock, lookup a possibly-changed entry at or after the
* 'start' position of the old entry.
*/
static vm_map_entry_t
vm_map_entry_in_transition(vm_map_t map, vm_offset_t in_start,
vm_offset_t *io_end, bool holes_ok, vm_map_entry_t in_entry)
{
vm_map_entry_t entry;
vm_offset_t start;
u_int last_timestamp;
VM_MAP_ASSERT_LOCKED(map);
KASSERT((in_entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0,
("not in-tranition map entry %p", in_entry));
/*
* We have not yet clipped the entry.
*/
start = MAX(in_start, in_entry->start);
in_entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP;
last_timestamp = map->timestamp;
if (vm_map_unlock_and_wait(map, 0)) {
/*
* Allow interruption of user wiring/unwiring?
*/
}
vm_map_lock(map);
if (last_timestamp + 1 == map->timestamp)
return (in_entry);
/*
* Look again for the entry because the map was modified while it was
* unlocked. Specifically, the entry may have been clipped, merged, or
* deleted.
*/
if (!vm_map_lookup_entry(map, start, &entry)) {
if (!holes_ok) {
*io_end = start;
return (NULL);
}
entry = vm_map_entry_succ(entry);
}
return (entry);
}
/*
* vm_map_unwire:
*
* Implements both kernel and user unwiring.
*/
int
vm_map_unwire(vm_map_t map, vm_offset_t start, vm_offset_t end,
int flags)
{
vm_map_entry_t entry, first_entry, next_entry, prev_entry;
int rv;
bool holes_ok, need_wakeup, user_unwire;
if (start == end)
return (KERN_SUCCESS);
holes_ok = (flags & VM_MAP_WIRE_HOLESOK) != 0;
user_unwire = (flags & VM_MAP_WIRE_USER) != 0;
vm_map_lock(map);
VM_MAP_RANGE_CHECK(map, start, end);
if (!vm_map_lookup_entry(map, start, &first_entry)) {
if (holes_ok)
first_entry = vm_map_entry_succ(first_entry);
else {
vm_map_unlock(map);
return (KERN_INVALID_ADDRESS);
}
}
rv = KERN_SUCCESS;
for (entry = first_entry; entry->start < end; entry = next_entry) {
if (entry->eflags & MAP_ENTRY_IN_TRANSITION) {
/*
* We have not yet clipped the entry.
*/
next_entry = vm_map_entry_in_transition(map, start,
&end, holes_ok, entry);
if (next_entry == NULL) {
if (entry == first_entry) {
vm_map_unlock(map);
return (KERN_INVALID_ADDRESS);
}
rv = KERN_INVALID_ADDRESS;
break;
}
first_entry = (entry == first_entry) ?
next_entry : NULL;
continue;
}
rv = vm_map_clip_start(map, entry, start);
if (rv != KERN_SUCCESS)
break;
rv = vm_map_clip_end(map, entry, end);
if (rv != KERN_SUCCESS)
break;
/*
* Mark the entry in case the map lock is released. (See
* above.)
*/
KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) == 0 &&
entry->wiring_thread == NULL,
("owned map entry %p", entry));
entry->eflags |= MAP_ENTRY_IN_TRANSITION;
entry->wiring_thread = curthread;
next_entry = vm_map_entry_succ(entry);
/*
* Check the map for holes in the specified region.
* If holes_ok, skip this check.
*/
if (!holes_ok &&
entry->end < end && next_entry->start > entry->end) {
end = entry->end;
rv = KERN_INVALID_ADDRESS;
break;
}
/*
* If system unwiring, require that the entry is system wired.
*/
if (!user_unwire &&
vm_map_entry_system_wired_count(entry) == 0) {
end = entry->end;
rv = KERN_INVALID_ARGUMENT;
break;
}
}
need_wakeup = false;
if (first_entry == NULL &&
!vm_map_lookup_entry(map, start, &first_entry)) {
KASSERT(holes_ok, ("vm_map_unwire: lookup failed"));
prev_entry = first_entry;
entry = vm_map_entry_succ(first_entry);
} else {
prev_entry = vm_map_entry_pred(first_entry);
entry = first_entry;
}
for (; entry->start < end;
prev_entry = entry, entry = vm_map_entry_succ(entry)) {
/*
* If holes_ok was specified, an empty
* space in the unwired region could have been mapped
* while the map lock was dropped for draining
* MAP_ENTRY_IN_TRANSITION. Moreover, another thread
* could be simultaneously wiring this new mapping
* entry. Detect these cases and skip any entries
* marked as in transition by us.
*/
if ((entry->eflags & MAP_ENTRY_IN_TRANSITION) == 0 ||
entry->wiring_thread != curthread) {
KASSERT(holes_ok,
("vm_map_unwire: !HOLESOK and new/changed entry"));
continue;
}
if (rv == KERN_SUCCESS && (!user_unwire ||
(entry->eflags & MAP_ENTRY_USER_WIRED))) {
if (entry->wired_count == 1)
vm_map_entry_unwire(map, entry);
else
entry->wired_count--;
if (user_unwire)
entry->eflags &= ~MAP_ENTRY_USER_WIRED;
}
KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0,
("vm_map_unwire: in-transition flag missing %p", entry));
KASSERT(entry->wiring_thread == curthread,
("vm_map_unwire: alien wire %p", entry));
entry->eflags &= ~MAP_ENTRY_IN_TRANSITION;
entry->wiring_thread = NULL;
if (entry->eflags & MAP_ENTRY_NEEDS_WAKEUP) {
entry->eflags &= ~MAP_ENTRY_NEEDS_WAKEUP;
need_wakeup = true;
}
vm_map_try_merge_entries(map, prev_entry, entry);
}
vm_map_try_merge_entries(map, prev_entry, entry);
vm_map_unlock(map);
if (need_wakeup)
vm_map_wakeup(map);
return (rv);
}
static void
vm_map_wire_user_count_sub(u_long npages)
{
atomic_subtract_long(&vm_user_wire_count, npages);
}
static bool
vm_map_wire_user_count_add(u_long npages)
{
u_long wired;
wired = vm_user_wire_count;
do {
if (npages + wired > vm_page_max_user_wired)
return (false);
} while (!atomic_fcmpset_long(&vm_user_wire_count, &wired,
npages + wired));
return (true);
}
/*
* vm_map_wire_entry_failure:
*
* Handle a wiring failure on the given entry.
*
* The map should be locked.
*/
static void
vm_map_wire_entry_failure(vm_map_t map, vm_map_entry_t entry,
vm_offset_t failed_addr)
{
VM_MAP_ASSERT_LOCKED(map);
KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0 &&
entry->wired_count == 1,
("vm_map_wire_entry_failure: entry %p isn't being wired", entry));
KASSERT(failed_addr < entry->end,
("vm_map_wire_entry_failure: entry %p was fully wired", entry));
/*
* If any pages at the start of this entry were successfully wired,
* then unwire them.
*/
if (failed_addr > entry->start) {
pmap_unwire(map->pmap, entry->start, failed_addr);
vm_object_unwire(entry->object.vm_object, entry->offset,
failed_addr - entry->start, PQ_ACTIVE);
}
/*
* Assign an out-of-range value to represent the failure to wire this
* entry.
*/
entry->wired_count = -1;
}
int
vm_map_wire(vm_map_t map, vm_offset_t start, vm_offset_t end, int flags)
{
int rv;
vm_map_lock(map);
rv = vm_map_wire_locked(map, start, end, flags);
vm_map_unlock(map);
return (rv);
}
/*
* vm_map_wire_locked:
*
* Implements both kernel and user wiring. Returns with the map locked,
* the map lock may be dropped.
*/
int
vm_map_wire_locked(vm_map_t map, vm_offset_t start, vm_offset_t end, int flags)
{
vm_map_entry_t entry, first_entry, next_entry, prev_entry;
vm_offset_t faddr, saved_end, saved_start;
u_long incr, npages;
u_int bidx, last_timestamp;
int rv;
bool holes_ok, need_wakeup, user_wire;
vm_prot_t prot;
VM_MAP_ASSERT_LOCKED(map);
if (start == end)
return (KERN_SUCCESS);
prot = 0;
if (flags & VM_MAP_WIRE_WRITE)
prot |= VM_PROT_WRITE;
holes_ok = (flags & VM_MAP_WIRE_HOLESOK) != 0;
user_wire = (flags & VM_MAP_WIRE_USER) != 0;
VM_MAP_RANGE_CHECK(map, start, end);
if (!vm_map_lookup_entry(map, start, &first_entry)) {
if (holes_ok)
first_entry = vm_map_entry_succ(first_entry);
else
return (KERN_INVALID_ADDRESS);
}
for (entry = first_entry; entry->start < end; entry = next_entry) {
if (entry->eflags & MAP_ENTRY_IN_TRANSITION) {
/*
* We have not yet clipped the entry.
*/
next_entry = vm_map_entry_in_transition(map, start,
&end, holes_ok, entry);
if (next_entry == NULL) {
if (entry == first_entry)
return (KERN_INVALID_ADDRESS);
rv = KERN_INVALID_ADDRESS;
goto done;
}
first_entry = (entry == first_entry) ?
next_entry : NULL;
continue;
}
rv = vm_map_clip_start(map, entry, start);
if (rv != KERN_SUCCESS)
goto done;
rv = vm_map_clip_end(map, entry, end);
if (rv != KERN_SUCCESS)
goto done;
/*
* Mark the entry in case the map lock is released. (See
* above.)
*/
KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) == 0 &&
entry->wiring_thread == NULL,
("owned map entry %p", entry));
entry->eflags |= MAP_ENTRY_IN_TRANSITION;
entry->wiring_thread = curthread;
if ((entry->protection & (VM_PROT_READ | VM_PROT_EXECUTE)) == 0
|| (entry->protection & prot) != prot) {
entry->eflags |= MAP_ENTRY_WIRE_SKIPPED;
if (!holes_ok) {
end = entry->end;
rv = KERN_INVALID_ADDRESS;
goto done;
}
} else if (entry->wired_count == 0) {
entry->wired_count++;
npages = atop(entry->end - entry->start);
if (user_wire && !vm_map_wire_user_count_add(npages)) {
vm_map_wire_entry_failure(map, entry,
entry->start);
end = entry->end;
rv = KERN_RESOURCE_SHORTAGE;
goto done;
}
/*
* Release the map lock, relying on the in-transition
* mark. Mark the map busy for fork.
*/
saved_start = entry->start;
saved_end = entry->end;
last_timestamp = map->timestamp;
bidx = MAP_ENTRY_SPLIT_BOUNDARY_INDEX(entry);
incr = pagesizes[bidx];
vm_map_busy(map);
vm_map_unlock(map);
for (faddr = saved_start; faddr < saved_end;
faddr += incr) {
/*
* Simulate a fault to get the page and enter
* it into the physical map.
*/
rv = vm_fault(map, faddr, VM_PROT_NONE,
VM_FAULT_WIRE, NULL);
if (rv != KERN_SUCCESS)
break;
}
vm_map_lock(map);
vm_map_unbusy(map);
if (last_timestamp + 1 != map->timestamp) {
/*
* Look again for the entry because the map was
* modified while it was unlocked. The entry
* may have been clipped, but NOT merged or
* deleted.
*/
if (!vm_map_lookup_entry(map, saved_start,
&next_entry))
KASSERT(false,
("vm_map_wire: lookup failed"));
first_entry = (entry == first_entry) ?
next_entry : NULL;
for (entry = next_entry; entry->end < saved_end;
entry = vm_map_entry_succ(entry)) {
/*
* In case of failure, handle entries
* that were not fully wired here;
* fully wired entries are handled
* later.
*/
if (rv != KERN_SUCCESS &&
faddr < entry->end)
vm_map_wire_entry_failure(map,
entry, faddr);
}
}
if (rv != KERN_SUCCESS) {
vm_map_wire_entry_failure(map, entry, faddr);
if (user_wire)
vm_map_wire_user_count_sub(npages);
end = entry->end;
goto done;
}
} else if (!user_wire ||
(entry->eflags & MAP_ENTRY_USER_WIRED) == 0) {
entry->wired_count++;
}
/*
* Check the map for holes in the specified region.
* If holes_ok was specified, skip this check.
*/
next_entry = vm_map_entry_succ(entry);
if (!holes_ok &&
entry->end < end && next_entry->start > entry->end) {
end = entry->end;
rv = KERN_INVALID_ADDRESS;
goto done;
}
}
rv = KERN_SUCCESS;
done:
need_wakeup = false;
if (first_entry == NULL &&
!vm_map_lookup_entry(map, start, &first_entry)) {
KASSERT(holes_ok, ("vm_map_wire: lookup failed"));
prev_entry = first_entry;
entry = vm_map_entry_succ(first_entry);
} else {
prev_entry = vm_map_entry_pred(first_entry);
entry = first_entry;
}
for (; entry->start < end;
prev_entry = entry, entry = vm_map_entry_succ(entry)) {
/*
* If holes_ok was specified, an empty
* space in the unwired region could have been mapped
* while the map lock was dropped for faulting in the
* pages or draining MAP_ENTRY_IN_TRANSITION.
* Moreover, another thread could be simultaneously
* wiring this new mapping entry. Detect these cases
* and skip any entries marked as in transition not by us.
*
* Another way to get an entry not marked with
* MAP_ENTRY_IN_TRANSITION is after failed clipping,
* which set rv to KERN_INVALID_ARGUMENT.
*/
if ((entry->eflags & MAP_ENTRY_IN_TRANSITION) == 0 ||
entry->wiring_thread != curthread) {
KASSERT(holes_ok || rv == KERN_INVALID_ARGUMENT,
("vm_map_wire: !HOLESOK and new/changed entry"));
continue;
}
if ((entry->eflags & MAP_ENTRY_WIRE_SKIPPED) != 0) {
/* do nothing */
} else if (rv == KERN_SUCCESS) {
if (user_wire)
entry->eflags |= MAP_ENTRY_USER_WIRED;
} else if (entry->wired_count == -1) {
/*
* Wiring failed on this entry. Thus, unwiring is
* unnecessary.
*/
entry->wired_count = 0;
} else if (!user_wire ||
(entry->eflags & MAP_ENTRY_USER_WIRED) == 0) {
/*
* Undo the wiring. Wiring succeeded on this entry
* but failed on a later entry.
*/
if (entry->wired_count == 1) {
vm_map_entry_unwire(map, entry);
if (user_wire)
vm_map_wire_user_count_sub(
atop(entry->end - entry->start));
} else
entry->wired_count--;
}
KASSERT((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0,
("vm_map_wire: in-transition flag missing %p", entry));
KASSERT(entry->wiring_thread == curthread,
("vm_map_wire: alien wire %p", entry));
entry->eflags &= ~(MAP_ENTRY_IN_TRANSITION |
MAP_ENTRY_WIRE_SKIPPED);
entry->wiring_thread = NULL;
if (entry->eflags & MAP_ENTRY_NEEDS_WAKEUP) {
entry->eflags &= ~MAP_ENTRY_NEEDS_WAKEUP;
need_wakeup = true;
}
vm_map_try_merge_entries(map, prev_entry, entry);
}
vm_map_try_merge_entries(map, prev_entry, entry);
if (need_wakeup)
vm_map_wakeup(map);
return (rv);
}
/*
* vm_map_sync
*
* Push any dirty cached pages in the address range to their pager.
* If syncio is TRUE, dirty pages are written synchronously.
* If invalidate is TRUE, any cached pages are freed as well.
*
* If the size of the region from start to end is zero, we are
* supposed to flush all modified pages within the region containing
* start. Unfortunately, a region can be split or coalesced with
* neighboring regions, making it difficult to determine what the
* original region was. Therefore, we approximate this requirement by
* flushing the current region containing start.
*
* Returns an error if any part of the specified range is not mapped.
*/
int
vm_map_sync(
vm_map_t map,
vm_offset_t start,
vm_offset_t end,
boolean_t syncio,
boolean_t invalidate)
{
vm_map_entry_t entry, first_entry, next_entry;
vm_size_t size;
vm_object_t object;
vm_ooffset_t offset;
unsigned int last_timestamp;
int bdry_idx;
boolean_t failed;
vm_map_lock_read(map);
VM_MAP_RANGE_CHECK(map, start, end);
if (!vm_map_lookup_entry(map, start, &first_entry)) {
vm_map_unlock_read(map);
return (KERN_INVALID_ADDRESS);
} else if (start == end) {
start = first_entry->start;
end = first_entry->end;
}
/*
* Make a first pass to check for user-wired memory, holes,
* and partial invalidation of largepage mappings.
*/
for (entry = first_entry; entry->start < end; entry = next_entry) {
if (invalidate) {
if ((entry->eflags & MAP_ENTRY_USER_WIRED) != 0) {
vm_map_unlock_read(map);
return (KERN_INVALID_ARGUMENT);
}
bdry_idx = MAP_ENTRY_SPLIT_BOUNDARY_INDEX(entry);
if (bdry_idx != 0 &&
((start & (pagesizes[bdry_idx] - 1)) != 0 ||
(end & (pagesizes[bdry_idx] - 1)) != 0)) {
vm_map_unlock_read(map);
return (KERN_INVALID_ARGUMENT);
}
}
next_entry = vm_map_entry_succ(entry);
if (end > entry->end &&
entry->end != next_entry->start) {
vm_map_unlock_read(map);
return (KERN_INVALID_ADDRESS);
}
}
if (invalidate)
pmap_remove(map->pmap, start, end);
failed = FALSE;
/*
* Make a second pass, cleaning/uncaching pages from the indicated
* objects as we go.
*/
for (entry = first_entry; entry->start < end;) {
offset = entry->offset + (start - entry->start);
size = (end <= entry->end ? end : entry->end) - start;
if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0) {
vm_map_t smap;
vm_map_entry_t tentry;
vm_size_t tsize;
smap = entry->object.sub_map;
vm_map_lock_read(smap);
(void) vm_map_lookup_entry(smap, offset, &tentry);
tsize = tentry->end - offset;
if (tsize < size)
size = tsize;
object = tentry->object.vm_object;
offset = tentry->offset + (offset - tentry->start);
vm_map_unlock_read(smap);
} else {
object = entry->object.vm_object;
}
vm_object_reference(object);
last_timestamp = map->timestamp;
vm_map_unlock_read(map);
if (!vm_object_sync(object, offset, size, syncio, invalidate))
failed = TRUE;
start += size;
vm_object_deallocate(object);
vm_map_lock_read(map);
if (last_timestamp == map->timestamp ||
!vm_map_lookup_entry(map, start, &entry))
entry = vm_map_entry_succ(entry);
}
vm_map_unlock_read(map);
return (failed ? KERN_FAILURE : KERN_SUCCESS);
}
/*
* vm_map_entry_unwire: [ internal use only ]
*
* Make the region specified by this entry pageable.
*
* The map in question should be locked.
* [This is the reason for this routine's existence.]
*/
static void
vm_map_entry_unwire(vm_map_t map, vm_map_entry_t entry)
{
vm_size_t size;
VM_MAP_ASSERT_LOCKED(map);
KASSERT(entry->wired_count > 0,
("vm_map_entry_unwire: entry %p isn't wired", entry));
size = entry->end - entry->start;
if ((entry->eflags & MAP_ENTRY_USER_WIRED) != 0)
vm_map_wire_user_count_sub(atop(size));
pmap_unwire(map->pmap, entry->start, entry->end);
vm_object_unwire(entry->object.vm_object, entry->offset, size,
PQ_ACTIVE);
entry->wired_count = 0;
}
static void
vm_map_entry_deallocate(vm_map_entry_t entry, boolean_t system_map)
{
if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0)
vm_object_deallocate(entry->object.vm_object);
uma_zfree(system_map ? kmapentzone : mapentzone, entry);
}
/*
* vm_map_entry_delete: [ internal use only ]
*
* Deallocate the given entry from the target map.
*/
static void
vm_map_entry_delete(vm_map_t map, vm_map_entry_t entry)
{
vm_object_t object;
vm_pindex_t offidxstart, offidxend, size1;
vm_size_t size;
vm_map_entry_unlink(map, entry, UNLINK_MERGE_NONE);
object = entry->object.vm_object;
if ((entry->eflags & MAP_ENTRY_GUARD) != 0) {
MPASS(entry->cred == NULL);
MPASS((entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0);
MPASS(object == NULL);
vm_map_entry_deallocate(entry, map->system_map);
return;
}
size = entry->end - entry->start;
map->size -= size;
if (entry->cred != NULL) {
swap_release_by_cred(size, entry->cred);
crfree(entry->cred);
}
if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0 || object == NULL) {
entry->object.vm_object = NULL;
} else if ((object->flags & OBJ_ANON) != 0 ||
object == kernel_object) {
KASSERT(entry->cred == NULL || object->cred == NULL ||
(entry->eflags & MAP_ENTRY_NEEDS_COPY),
("OVERCOMMIT vm_map_entry_delete: both cred %p", entry));
offidxstart = OFF_TO_IDX(entry->offset);
offidxend = offidxstart + atop(size);
VM_OBJECT_WLOCK(object);
if (object->ref_count != 1 &&
((object->flags & OBJ_ONEMAPPING) != 0 ||
object == kernel_object)) {
vm_object_collapse(object);
/*
* The option OBJPR_NOTMAPPED can be passed here
* because vm_map_delete() already performed
* pmap_remove() on the only mapping to this range
* of pages.
*/
vm_object_page_remove(object, offidxstart, offidxend,
OBJPR_NOTMAPPED);
if (offidxend >= object->size &&
offidxstart < object->size) {
size1 = object->size;
object->size = offidxstart;
if (object->cred != NULL) {
size1 -= object->size;
KASSERT(object->charge >= ptoa(size1),
("object %p charge < 0", object));
swap_release_by_cred(ptoa(size1),
object->cred);
object->charge -= ptoa(size1);
}
}
}
VM_OBJECT_WUNLOCK(object);
}
if (map->system_map)
vm_map_entry_deallocate(entry, TRUE);
else {
entry->defer_next = curthread->td_map_def_user;
curthread->td_map_def_user = entry;
}
}
/*
* vm_map_delete: [ internal use only ]
*
* Deallocates the given address range from the target
* map.
*/
int
vm_map_delete(vm_map_t map, vm_offset_t start, vm_offset_t end)
{
vm_map_entry_t entry, next_entry, scratch_entry;
int rv;
VM_MAP_ASSERT_LOCKED(map);
if (start == end)
return (KERN_SUCCESS);
/*
* Find the start of the region, and clip it.
* Step through all entries in this region.
*/
rv = vm_map_lookup_clip_start(map, start, &entry, &scratch_entry);
if (rv != KERN_SUCCESS)
return (rv);
for (; entry->start < end; entry = next_entry) {
/*
* Wait for wiring or unwiring of an entry to complete.
* Also wait for any system wirings to disappear on
* user maps.
*/
if ((entry->eflags & MAP_ENTRY_IN_TRANSITION) != 0 ||
(vm_map_pmap(map) != kernel_pmap &&
vm_map_entry_system_wired_count(entry) != 0)) {
unsigned int last_timestamp;
vm_offset_t saved_start;
saved_start = entry->start;
entry->eflags |= MAP_ENTRY_NEEDS_WAKEUP;
last_timestamp = map->timestamp;
(void) vm_map_unlock_and_wait(map, 0);
vm_map_lock(map);
if (last_timestamp + 1 != map->timestamp) {
/*
* Look again for the entry because the map was
* modified while it was unlocked.
* Specifically, the entry may have been
* clipped, merged, or deleted.
*/
rv = vm_map_lookup_clip_start(map, saved_start,
&next_entry, &scratch_entry);
if (rv != KERN_SUCCESS)
break;
} else
next_entry = entry;
continue;
}
/* XXXKIB or delete to the upper superpage boundary ? */
rv = vm_map_clip_end(map, entry, end);
if (rv != KERN_SUCCESS)
break;
next_entry = vm_map_entry_succ(entry);
/*
* Unwire before removing addresses from the pmap; otherwise,
* unwiring will put the entries back in the pmap.
*/
if (entry->wired_count != 0)
vm_map_entry_unwire(map, entry);
/*
* Remove mappings for the pages, but only if the
* mappings could exist. For instance, it does not
* make sense to call pmap_remove() for guard entries.
*/
if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0 ||
entry->object.vm_object != NULL)
pmap_map_delete(map->pmap, entry->start, entry->end);
/*
* Delete the entry only after removing all pmap
* entries pointing to its pages. (Otherwise, its
* page frames may be reallocated, and any modify bits
* will be set in the wrong object!)
*/
vm_map_entry_delete(map, entry);
}
return (rv);
}
/*
* vm_map_remove:
*
* Remove the given address range from the target map.
* This is the exported form of vm_map_delete.
*/
int
vm_map_remove(vm_map_t map, vm_offset_t start, vm_offset_t end)
{
int result;
vm_map_lock(map);
VM_MAP_RANGE_CHECK(map, start, end);
result = vm_map_delete(map, start, end);
vm_map_unlock(map);
return (result);
}
/*
* vm_map_check_protection:
*
* Assert that the target map allows the specified privilege on the
* entire address region given. The entire region must be allocated.
*
* WARNING! This code does not and should not check whether the
* contents of the region is accessible. For example a smaller file
* might be mapped into a larger address space.
*
* NOTE! This code is also called by munmap().
*
* The map must be locked. A read lock is sufficient.
*/
boolean_t
vm_map_check_protection(vm_map_t map, vm_offset_t start, vm_offset_t end,
vm_prot_t protection)
{
vm_map_entry_t entry;
vm_map_entry_t tmp_entry;
if (!vm_map_lookup_entry(map, start, &tmp_entry))
return (FALSE);
entry = tmp_entry;
while (start < end) {
/*
* No holes allowed!
*/
if (start < entry->start)
return (FALSE);
/*
* Check protection associated with entry.
*/
if ((entry->protection & protection) != protection)
return (FALSE);
/* go to next entry */
start = entry->end;
entry = vm_map_entry_succ(entry);
}
return (TRUE);
}
/*
*
* vm_map_copy_swap_object:
*
* Copies a swap-backed object from an existing map entry to a
* new one. Carries forward the swap charge. May change the
* src object on return.
*/
static void
vm_map_copy_swap_object(vm_map_entry_t src_entry, vm_map_entry_t dst_entry,
vm_offset_t size, vm_ooffset_t *fork_charge)
{
vm_object_t src_object;
struct ucred *cred;
int charged;
src_object = src_entry->object.vm_object;
charged = ENTRY_CHARGED(src_entry);
if ((src_object->flags & OBJ_ANON) != 0) {
VM_OBJECT_WLOCK(src_object);
vm_object_collapse(src_object);
if ((src_object->flags & OBJ_ONEMAPPING) != 0) {
vm_object_split(src_entry);
src_object = src_entry->object.vm_object;
}
vm_object_reference_locked(src_object);
vm_object_clear_flag(src_object, OBJ_ONEMAPPING);
VM_OBJECT_WUNLOCK(src_object);
} else
vm_object_reference(src_object);
if (src_entry->cred != NULL &&
!(src_entry->eflags & MAP_ENTRY_NEEDS_COPY)) {
KASSERT(src_object->cred == NULL,
("OVERCOMMIT: vm_map_copy_anon_entry: cred %p",
src_object));
src_object->cred = src_entry->cred;
src_object->charge = size;
}
dst_entry->object.vm_object = src_object;
if (charged) {
cred = curthread->td_ucred;
crhold(cred);
dst_entry->cred = cred;
*fork_charge += size;
if (!(src_entry->eflags & MAP_ENTRY_NEEDS_COPY)) {
crhold(cred);
src_entry->cred = cred;
*fork_charge += size;
}
}
}
/*
* vm_map_copy_entry:
*
* Copies the contents of the source entry to the destination
* entry. The entries *must* be aligned properly.
*/
static void
vm_map_copy_entry(
vm_map_t src_map,
vm_map_t dst_map,
vm_map_entry_t src_entry,
vm_map_entry_t dst_entry,
vm_ooffset_t *fork_charge)
{
vm_object_t src_object;
vm_map_entry_t fake_entry;
vm_offset_t size;
VM_MAP_ASSERT_LOCKED(dst_map);
if ((dst_entry->eflags|src_entry->eflags) & MAP_ENTRY_IS_SUB_MAP)
return;
if (src_entry->wired_count == 0 ||
(src_entry->protection & VM_PROT_WRITE) == 0) {
/*
* If the source entry is marked needs_copy, it is already
* write-protected.
*/
if ((src_entry->eflags & MAP_ENTRY_NEEDS_COPY) == 0 &&
(src_entry->protection & VM_PROT_WRITE) != 0) {
pmap_protect(src_map->pmap,
src_entry->start,
src_entry->end,
src_entry->protection & ~VM_PROT_WRITE);
}
/*
* Make a copy of the object.
*/
size = src_entry->end - src_entry->start;
if ((src_object = src_entry->object.vm_object) != NULL) {
if ((src_object->flags & OBJ_SWAP) != 0) {
vm_map_copy_swap_object(src_entry, dst_entry,
size, fork_charge);
/* May have split/collapsed, reload obj. */
src_object = src_entry->object.vm_object;
} else {
vm_object_reference(src_object);
dst_entry->object.vm_object = src_object;
}
src_entry->eflags |= MAP_ENTRY_COW |
MAP_ENTRY_NEEDS_COPY;
dst_entry->eflags |= MAP_ENTRY_COW |
MAP_ENTRY_NEEDS_COPY;
dst_entry->offset = src_entry->offset;
if (src_entry->eflags & MAP_ENTRY_WRITECNT) {
/*
* MAP_ENTRY_WRITECNT cannot
* indicate write reference from
* src_entry, since the entry is
* marked as needs copy. Allocate a
* fake entry that is used to
* decrement object->un_pager writecount
* at the appropriate time. Attach
* fake_entry to the deferred list.
*/
fake_entry = vm_map_entry_create(dst_map);
fake_entry->eflags = MAP_ENTRY_WRITECNT;
src_entry->eflags &= ~MAP_ENTRY_WRITECNT;
vm_object_reference(src_object);
fake_entry->object.vm_object = src_object;
fake_entry->start = src_entry->start;
fake_entry->end = src_entry->end;
fake_entry->defer_next =
curthread->td_map_def_user;
curthread->td_map_def_user = fake_entry;
}
pmap_copy(dst_map->pmap, src_map->pmap,
dst_entry->start, dst_entry->end - dst_entry->start,
src_entry->start);
} else {
dst_entry->object.vm_object = NULL;
if ((dst_entry->eflags & MAP_ENTRY_GUARD) == 0)
dst_entry->offset = 0;
if (src_entry->cred != NULL) {
dst_entry->cred = curthread->td_ucred;
crhold(dst_entry->cred);
*fork_charge += size;
}
}
} else {
/*
* We don't want to make writeable wired pages copy-on-write.
* Immediately copy these pages into the new map by simulating
* page faults. The new pages are pageable.
*/
vm_fault_copy_entry(dst_map, src_map, dst_entry, src_entry,
fork_charge);
}
}
/*
* vmspace_map_entry_forked:
* Update the newly-forked vmspace each time a map entry is inherited
* or copied. The values for vm_dsize and vm_tsize are approximate
* (and mostly-obsolete ideas in the face of mmap(2) et al.)
*/
static void
vmspace_map_entry_forked(const struct vmspace *vm1, struct vmspace *vm2,
vm_map_entry_t entry)
{
vm_size_t entrysize;
vm_offset_t newend;
if ((entry->eflags & MAP_ENTRY_GUARD) != 0)
return;
entrysize = entry->end - entry->start;
vm2->vm_map.size += entrysize;
if (entry->eflags & (MAP_ENTRY_GROWS_DOWN | MAP_ENTRY_GROWS_UP)) {
vm2->vm_ssize += btoc(entrysize);
} else if (entry->start >= (vm_offset_t)vm1->vm_daddr &&
entry->start < (vm_offset_t)vm1->vm_daddr + ctob(vm1->vm_dsize)) {
newend = MIN(entry->end,
(vm_offset_t)vm1->vm_daddr + ctob(vm1->vm_dsize));
vm2->vm_dsize += btoc(newend - entry->start);
} else if (entry->start >= (vm_offset_t)vm1->vm_taddr &&
entry->start < (vm_offset_t)vm1->vm_taddr + ctob(vm1->vm_tsize)) {
newend = MIN(entry->end,
(vm_offset_t)vm1->vm_taddr + ctob(vm1->vm_tsize));
vm2->vm_tsize += btoc(newend - entry->start);
}
}
/*
* vmspace_fork:
* Create a new process vmspace structure and vm_map
* based on those of an existing process. The new map
* is based on the old map, according to the inheritance
* values on the regions in that map.
*
* XXX It might be worth coalescing the entries added to the new vmspace.
*
* The source map must not be locked.
*/
struct vmspace *
vmspace_fork(struct vmspace *vm1, vm_ooffset_t *fork_charge)
{
struct vmspace *vm2;
vm_map_t new_map, old_map;
vm_map_entry_t new_entry, old_entry;
vm_object_t object;
int error, locked __diagused;
vm_inherit_t inh;
old_map = &vm1->vm_map;
/* Copy immutable fields of vm1 to vm2. */
vm2 = vmspace_alloc(vm_map_min(old_map), vm_map_max(old_map),
pmap_pinit);
if (vm2 == NULL)
return (NULL);
vm2->vm_taddr = vm1->vm_taddr;
vm2->vm_daddr = vm1->vm_daddr;
vm2->vm_maxsaddr = vm1->vm_maxsaddr;
vm2->vm_stacktop = vm1->vm_stacktop;
vm2->vm_shp_base = vm1->vm_shp_base;
vm_map_lock(old_map);
if (old_map->busy)
vm_map_wait_busy(old_map);
new_map = &vm2->vm_map;
locked = vm_map_trylock(new_map); /* trylock to silence WITNESS */
KASSERT(locked, ("vmspace_fork: lock failed"));
error = pmap_vmspace_copy(new_map->pmap, old_map->pmap);
if (error != 0) {
sx_xunlock(&old_map->lock);
sx_xunlock(&new_map->lock);
vm_map_process_deferred();
vmspace_free(vm2);
return (NULL);
}
new_map->anon_loc = old_map->anon_loc;
new_map->flags |= old_map->flags & (MAP_ASLR | MAP_ASLR_IGNSTART |
MAP_ASLR_STACK | MAP_WXORX);
VM_MAP_ENTRY_FOREACH(old_entry, old_map) {
if ((old_entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0)
panic("vm_map_fork: encountered a submap");
inh = old_entry->inheritance;
if ((old_entry->eflags & MAP_ENTRY_GUARD) != 0 &&
inh != VM_INHERIT_NONE)
inh = VM_INHERIT_COPY;
switch (inh) {
case VM_INHERIT_NONE:
break;
case VM_INHERIT_SHARE:
/*
* Clone the entry, creating the shared object if
* necessary.
*/
object = old_entry->object.vm_object;
if (object == NULL) {
vm_map_entry_back(old_entry);
object = old_entry->object.vm_object;
}
/*
* Add the reference before calling vm_object_shadow
* to insure that a shadow object is created.
*/
vm_object_reference(object);
if (old_entry->eflags & MAP_ENTRY_NEEDS_COPY) {
vm_object_shadow(&old_entry->object.vm_object,
&old_entry->offset,
old_entry->end - old_entry->start,
old_entry->cred,
/* Transfer the second reference too. */
true);
old_entry->eflags &= ~MAP_ENTRY_NEEDS_COPY;
old_entry->cred = NULL;
/*
* As in vm_map_merged_neighbor_dispose(),
* the vnode lock will not be acquired in
* this call to vm_object_deallocate().
*/
vm_object_deallocate(object);
object = old_entry->object.vm_object;
} else {
VM_OBJECT_WLOCK(object);
vm_object_clear_flag(object, OBJ_ONEMAPPING);
if (old_entry->cred != NULL) {
KASSERT(object->cred == NULL,
("vmspace_fork both cred"));
object->cred = old_entry->cred;
object->charge = old_entry->end -
old_entry->start;
old_entry->cred = NULL;
}
/*
* Assert the correct state of the vnode
* v_writecount while the object is locked, to
* not relock it later for the assertion
* correctness.
*/
if (old_entry->eflags & MAP_ENTRY_WRITECNT &&
object->type == OBJT_VNODE) {
KASSERT(((struct vnode *)object->
handle)->v_writecount > 0,
("vmspace_fork: v_writecount %p",
object));
KASSERT(object->un_pager.vnp.
writemappings > 0,
("vmspace_fork: vnp.writecount %p",
object));
}
VM_OBJECT_WUNLOCK(object);
}
/*
* Clone the entry, referencing the shared object.
*/
new_entry = vm_map_entry_create(new_map);
*new_entry = *old_entry;
new_entry->eflags &= ~(MAP_ENTRY_USER_WIRED |
MAP_ENTRY_IN_TRANSITION);
new_entry->wiring_thread = NULL;
new_entry->wired_count = 0;
if (new_entry->eflags & MAP_ENTRY_WRITECNT) {
vm_pager_update_writecount(object,
new_entry->start, new_entry->end);
}
vm_map_entry_set_vnode_text(new_entry, true);
/*
* Insert the entry into the new map -- we know we're
* inserting at the end of the new map.
*/
vm_map_entry_link(new_map, new_entry);
vmspace_map_entry_forked(vm1, vm2, new_entry);
/*
* Update the physical map
*/
pmap_copy(new_map->pmap, old_map->pmap,
new_entry->start,
(old_entry->end - old_entry->start),
old_entry->start);
break;
case VM_INHERIT_COPY:
/*
* Clone the entry and link into the map.
*/
new_entry = vm_map_entry_create(new_map);
*new_entry = *old_entry;
/*
* Copied entry is COW over the old object.
*/
new_entry->eflags &= ~(MAP_ENTRY_USER_WIRED |
MAP_ENTRY_IN_TRANSITION | MAP_ENTRY_WRITECNT);
new_entry->wiring_thread = NULL;
new_entry->wired_count = 0;
new_entry->object.vm_object = NULL;
new_entry->cred = NULL;
vm_map_entry_link(new_map, new_entry);
vmspace_map_entry_forked(vm1, vm2, new_entry);
vm_map_copy_entry(old_map, new_map, old_entry,
new_entry, fork_charge);
vm_map_entry_set_vnode_text(new_entry, true);
break;
case VM_INHERIT_ZERO:
/*
* Create a new anonymous mapping entry modelled from
* the old one.
*/
new_entry = vm_map_entry_create(new_map);
memset(new_entry, 0, sizeof(*new_entry));
new_entry->start = old_entry->start;
new_entry->end = old_entry->end;
new_entry->eflags = old_entry->eflags &
~(MAP_ENTRY_USER_WIRED | MAP_ENTRY_IN_TRANSITION |
MAP_ENTRY_WRITECNT | MAP_ENTRY_VN_EXEC |
MAP_ENTRY_SPLIT_BOUNDARY_MASK);
new_entry->protection = old_entry->protection;
new_entry->max_protection = old_entry->max_protection;
new_entry->inheritance = VM_INHERIT_ZERO;
vm_map_entry_link(new_map, new_entry);
vmspace_map_entry_forked(vm1, vm2, new_entry);
new_entry->cred = curthread->td_ucred;
crhold(new_entry->cred);
*fork_charge += (new_entry->end - new_entry->start);
break;
}
}
/*
* Use inlined vm_map_unlock() to postpone handling the deferred
* map entries, which cannot be done until both old_map and
* new_map locks are released.
*/
sx_xunlock(&old_map->lock);
sx_xunlock(&new_map->lock);
vm_map_process_deferred();
return (vm2);
}
/*
* Create a process's stack for exec_new_vmspace(). This function is never
* asked to wire the newly created stack.
*/
int
vm_map_stack(vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize,
vm_prot_t prot, vm_prot_t max, int cow)
{
vm_size_t growsize, init_ssize;
rlim_t vmemlim;
int rv;
MPASS((map->flags & MAP_WIREFUTURE) == 0);
growsize = sgrowsiz;
init_ssize = (max_ssize < growsize) ? max_ssize : growsize;
vm_map_lock(map);
vmemlim = lim_cur(curthread, RLIMIT_VMEM);
/* If we would blow our VMEM resource limit, no go */
if (map->size + init_ssize > vmemlim) {
rv = KERN_NO_SPACE;
goto out;
}
rv = vm_map_stack_locked(map, addrbos, max_ssize, growsize, prot,
max, cow);
out:
vm_map_unlock(map);
return (rv);
}
static int stack_guard_page = 1;
SYSCTL_INT(_security_bsd, OID_AUTO, stack_guard_page, CTLFLAG_RWTUN,
&stack_guard_page, 0,
"Specifies the number of guard pages for a stack that grows");
static int
vm_map_stack_locked(vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize,
vm_size_t growsize, vm_prot_t prot, vm_prot_t max, int cow)
{
vm_map_entry_t gap_entry, new_entry, prev_entry;
vm_offset_t bot, gap_bot, gap_top, top;
vm_size_t init_ssize, sgp;
int orient, rv;
/*
* The stack orientation is piggybacked with the cow argument.
* Extract it into orient and mask the cow argument so that we
* don't pass it around further.
*/
orient = cow & (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP);
KASSERT(orient != 0, ("No stack grow direction"));
KASSERT(orient != (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP),
("bi-dir stack"));
if (max_ssize == 0 ||
!vm_map_range_valid(map, addrbos, addrbos + max_ssize))
return (KERN_INVALID_ADDRESS);
sgp = ((curproc->p_flag2 & P2_STKGAP_DISABLE) != 0 ||
(curproc->p_fctl0 & NT_FREEBSD_FCTL_STKGAP_DISABLE) != 0) ? 0 :
(vm_size_t)stack_guard_page * PAGE_SIZE;
if (sgp >= max_ssize)
return (KERN_INVALID_ARGUMENT);
init_ssize = growsize;
if (max_ssize < init_ssize + sgp)
init_ssize = max_ssize - sgp;
/* If addr is already mapped, no go */
if (vm_map_lookup_entry(map, addrbos, &prev_entry))
return (KERN_NO_SPACE);
/*
* If we can't accommodate max_ssize in the current mapping, no go.
*/
if (vm_map_entry_succ(prev_entry)->start < addrbos + max_ssize)
return (KERN_NO_SPACE);
/*
* We initially map a stack of only init_ssize. We will grow as
* needed later. Depending on the orientation of the stack (i.e.
* the grow direction) we either map at the top of the range, the
* bottom of the range or in the middle.
*
* Note: we would normally expect prot and max to be VM_PROT_ALL,
* and cow to be 0. Possibly we should eliminate these as input
* parameters, and just pass these values here in the insert call.
*/
if (orient == MAP_STACK_GROWS_DOWN) {
bot = addrbos + max_ssize - init_ssize;
top = bot + init_ssize;
gap_bot = addrbos;
gap_top = bot;
} else /* if (orient == MAP_STACK_GROWS_UP) */ {
bot = addrbos;
top = bot + init_ssize;
gap_bot = top;
gap_top = addrbos + max_ssize;
}
rv = vm_map_insert1(map, NULL, 0, bot, top, prot, max, cow,
&new_entry);
if (rv != KERN_SUCCESS)
return (rv);
KASSERT(new_entry->end == top || new_entry->start == bot,
("Bad entry start/end for new stack entry"));
KASSERT((orient & MAP_STACK_GROWS_DOWN) == 0 ||
(new_entry->eflags & MAP_ENTRY_GROWS_DOWN) != 0,
("new entry lacks MAP_ENTRY_GROWS_DOWN"));
KASSERT((orient & MAP_STACK_GROWS_UP) == 0 ||
(new_entry->eflags & MAP_ENTRY_GROWS_UP) != 0,
("new entry lacks MAP_ENTRY_GROWS_UP"));
if (gap_bot == gap_top)
return (KERN_SUCCESS);
rv = vm_map_insert1(map, NULL, 0, gap_bot, gap_top, VM_PROT_NONE,
VM_PROT_NONE, MAP_CREATE_GUARD | (orient == MAP_STACK_GROWS_DOWN ?
MAP_CREATE_STACK_GAP_DN : MAP_CREATE_STACK_GAP_UP), &gap_entry);
if (rv == KERN_SUCCESS) {
KASSERT((gap_entry->eflags & MAP_ENTRY_GUARD) != 0,
("entry %p not gap %#x", gap_entry, gap_entry->eflags));
KASSERT((gap_entry->eflags & (MAP_ENTRY_STACK_GAP_DN |
MAP_ENTRY_STACK_GAP_UP)) != 0,
("entry %p not stack gap %#x", gap_entry,
gap_entry->eflags));
/*
* Gap can never successfully handle a fault, so
* read-ahead logic is never used for it. Re-use
* next_read of the gap entry to store
* stack_guard_page for vm_map_growstack().
* Similarly, since a gap cannot have a backing object,
* store the original stack protections in the
* object offset.
*/
gap_entry->next_read = sgp;
gap_entry->offset = prot | PROT_MAX(max);
} else {
(void)vm_map_delete(map, bot, top);
}
return (rv);
}
/*
* Attempts to grow a vm stack entry. Returns KERN_SUCCESS if we
* successfully grow the stack.
*/
static int
vm_map_growstack(vm_map_t map, vm_offset_t addr, vm_map_entry_t gap_entry)
{
vm_map_entry_t stack_entry;
struct proc *p;
struct vmspace *vm;
struct ucred *cred;
vm_offset_t gap_end, gap_start, grow_start;
vm_size_t grow_amount, guard, max_grow, sgp;
vm_prot_t prot, max;
rlim_t lmemlim, stacklim, vmemlim;
int rv, rv1 __diagused;
bool gap_deleted, grow_down, is_procstack;
#ifdef notyet
uint64_t limit;
#endif
#ifdef RACCT
int error __diagused;
#endif
p = curproc;
vm = p->p_vmspace;
/*
* Disallow stack growth when the access is performed by a
* debugger or AIO daemon. The reason is that the wrong
* resource limits are applied.
*/
if (p != initproc && (map != &p->p_vmspace->vm_map ||
p->p_textvp == NULL))
return (KERN_FAILURE);
MPASS(!map->system_map);
lmemlim = lim_cur(curthread, RLIMIT_MEMLOCK);
stacklim = lim_cur(curthread, RLIMIT_STACK);
vmemlim = lim_cur(curthread, RLIMIT_VMEM);
retry:
/* If addr is not in a hole for a stack grow area, no need to grow. */
if (gap_entry == NULL && !vm_map_lookup_entry(map, addr, &gap_entry))
return (KERN_FAILURE);
if ((gap_entry->eflags & MAP_ENTRY_GUARD) == 0)
return (KERN_SUCCESS);
if ((gap_entry->eflags & MAP_ENTRY_STACK_GAP_DN) != 0) {
stack_entry = vm_map_entry_succ(gap_entry);
if ((stack_entry->eflags & MAP_ENTRY_GROWS_DOWN) == 0 ||
stack_entry->start != gap_entry->end)
return (KERN_FAILURE);
grow_amount = round_page(stack_entry->start - addr);
grow_down = true;
} else if ((gap_entry->eflags & MAP_ENTRY_STACK_GAP_UP) != 0) {
stack_entry = vm_map_entry_pred(gap_entry);
if ((stack_entry->eflags & MAP_ENTRY_GROWS_UP) == 0 ||
stack_entry->end != gap_entry->start)
return (KERN_FAILURE);
grow_amount = round_page(addr + 1 - stack_entry->end);
grow_down = false;
} else {
return (KERN_FAILURE);
}
guard = ((curproc->p_flag2 & P2_STKGAP_DISABLE) != 0 ||
(curproc->p_fctl0 & NT_FREEBSD_FCTL_STKGAP_DISABLE) != 0) ? 0 :
gap_entry->next_read;
max_grow = gap_entry->end - gap_entry->start;
if (guard > max_grow)
return (KERN_NO_SPACE);
max_grow -= guard;
if (grow_amount > max_grow)
return (KERN_NO_SPACE);
/*
* If this is the main process stack, see if we're over the stack
* limit.
*/
is_procstack = addr >= (vm_offset_t)vm->vm_maxsaddr &&
addr < (vm_offset_t)vm->vm_stacktop;
if (is_procstack && (ctob(vm->vm_ssize) + grow_amount > stacklim))
return (KERN_NO_SPACE);
#ifdef RACCT
if (racct_enable) {
PROC_LOCK(p);
if (is_procstack && racct_set(p, RACCT_STACK,
ctob(vm->vm_ssize) + grow_amount)) {
PROC_UNLOCK(p);
return (KERN_NO_SPACE);
}
PROC_UNLOCK(p);
}
#endif
grow_amount = roundup(grow_amount, sgrowsiz);
if (grow_amount > max_grow)
grow_amount = max_grow;
if (is_procstack && (ctob(vm->vm_ssize) + grow_amount > stacklim)) {
grow_amount = trunc_page((vm_size_t)stacklim) -
ctob(vm->vm_ssize);
}
#ifdef notyet
PROC_LOCK(p);
limit = racct_get_available(p, RACCT_STACK);
PROC_UNLOCK(p);
if (is_procstack && (ctob(vm->vm_ssize) + grow_amount > limit))
grow_amount = limit - ctob(vm->vm_ssize);
#endif
if (!old_mlock && (map->flags & MAP_WIREFUTURE) != 0) {
if (ptoa(pmap_wired_count(map->pmap)) + grow_amount > lmemlim) {
rv = KERN_NO_SPACE;
goto out;
}
#ifdef RACCT
if (racct_enable) {
PROC_LOCK(p);
if (racct_set(p, RACCT_MEMLOCK,
ptoa(pmap_wired_count(map->pmap)) + grow_amount)) {
PROC_UNLOCK(p);
rv = KERN_NO_SPACE;
goto out;
}
PROC_UNLOCK(p);
}
#endif
}
/* If we would blow our VMEM resource limit, no go */
if (map->size + grow_amount > vmemlim) {
rv = KERN_NO_SPACE;
goto out;
}
#ifdef RACCT
if (racct_enable) {
PROC_LOCK(p);
if (racct_set(p, RACCT_VMEM, map->size + grow_amount)) {
PROC_UNLOCK(p);
rv = KERN_NO_SPACE;
goto out;
}
PROC_UNLOCK(p);
}
#endif
if (vm_map_lock_upgrade(map)) {
gap_entry = NULL;
vm_map_lock_read(map);
goto retry;
}
if (grow_down) {
/*
* The gap_entry "offset" field is overloaded. See
* vm_map_stack_locked().
*/
prot = PROT_EXTRACT(gap_entry->offset);
max = PROT_MAX_EXTRACT(gap_entry->offset);
sgp = gap_entry->next_read;
grow_start = gap_entry->end - grow_amount;
if (gap_entry->start + grow_amount == gap_entry->end) {
gap_start = gap_entry->start;
gap_end = gap_entry->end;
vm_map_entry_delete(map, gap_entry);
gap_deleted = true;
} else {
MPASS(gap_entry->start < gap_entry->end - grow_amount);
vm_map_entry_resize(map, gap_entry, -grow_amount);
gap_deleted = false;
}
rv = vm_map_insert(map, NULL, 0, grow_start,
grow_start + grow_amount, prot, max, MAP_STACK_GROWS_DOWN);
if (rv != KERN_SUCCESS) {
if (gap_deleted) {
rv1 = vm_map_insert1(map, NULL, 0, gap_start,
gap_end, VM_PROT_NONE, VM_PROT_NONE,
MAP_CREATE_GUARD | MAP_CREATE_STACK_GAP_DN,
&gap_entry);
MPASS(rv1 == KERN_SUCCESS);
gap_entry->next_read = sgp;
gap_entry->offset = prot | PROT_MAX(max);
} else
vm_map_entry_resize(map, gap_entry,
grow_amount);
}
} else {
grow_start = stack_entry->end;
cred = stack_entry->cred;
if (cred == NULL && stack_entry->object.vm_object != NULL)
cred = stack_entry->object.vm_object->cred;
if (cred != NULL && !swap_reserve_by_cred(grow_amount, cred))
rv = KERN_NO_SPACE;
/* Grow the underlying object if applicable. */
else if (stack_entry->object.vm_object == NULL ||
vm_object_coalesce(stack_entry->object.vm_object,
stack_entry->offset,
(vm_size_t)(stack_entry->end - stack_entry->start),
grow_amount, cred != NULL)) {
if (gap_entry->start + grow_amount == gap_entry->end) {
vm_map_entry_delete(map, gap_entry);
vm_map_entry_resize(map, stack_entry,
grow_amount);
} else {
gap_entry->start += grow_amount;
stack_entry->end += grow_amount;
}
map->size += grow_amount;
rv = KERN_SUCCESS;
} else
rv = KERN_FAILURE;
}
if (rv == KERN_SUCCESS && is_procstack)
vm->vm_ssize += btoc(grow_amount);
/*
* Heed the MAP_WIREFUTURE flag if it was set for this process.
*/
if (rv == KERN_SUCCESS && (map->flags & MAP_WIREFUTURE) != 0) {
rv = vm_map_wire_locked(map, grow_start,
grow_start + grow_amount,
VM_MAP_WIRE_USER | VM_MAP_WIRE_NOHOLES);
}
vm_map_lock_downgrade(map);
out:
#ifdef RACCT
if (racct_enable && rv != KERN_SUCCESS) {
PROC_LOCK(p);
error = racct_set(p, RACCT_VMEM, map->size);
KASSERT(error == 0, ("decreasing RACCT_VMEM failed"));
if (!old_mlock) {
error = racct_set(p, RACCT_MEMLOCK,
ptoa(pmap_wired_count(map->pmap)));
KASSERT(error == 0, ("decreasing RACCT_MEMLOCK failed"));
}
error = racct_set(p, RACCT_STACK, ctob(vm->vm_ssize));
KASSERT(error == 0, ("decreasing RACCT_STACK failed"));
PROC_UNLOCK(p);
}
#endif
return (rv);
}
/*
* Unshare the specified VM space for exec. If other processes are
* mapped to it, then create a new one. The new vmspace is null.
*/
int
vmspace_exec(struct proc *p, vm_offset_t minuser, vm_offset_t maxuser)
{
struct vmspace *oldvmspace = p->p_vmspace;
struct vmspace *newvmspace;
KASSERT((curthread->td_pflags & TDP_EXECVMSPC) == 0,
("vmspace_exec recursed"));
newvmspace = vmspace_alloc(minuser, maxuser, pmap_pinit);
if (newvmspace == NULL)
return (ENOMEM);
newvmspace->vm_swrss = oldvmspace->vm_swrss;
/*
* This code is written like this for prototype purposes. The
* goal is to avoid running down the vmspace here, but let the
* other process's that are still using the vmspace to finally
* run it down. Even though there is little or no chance of blocking
* here, it is a good idea to keep this form for future mods.
*/
PROC_VMSPACE_LOCK(p);
p->p_vmspace = newvmspace;
PROC_VMSPACE_UNLOCK(p);
if (p == curthread->td_proc)
pmap_activate(curthread);
curthread->td_pflags |= TDP_EXECVMSPC;
return (0);
}
/*
* Unshare the specified VM space for forcing COW. This
* is called by rfork, for the (RFMEM|RFPROC) == 0 case.
*/
int
vmspace_unshare(struct proc *p)
{
struct vmspace *oldvmspace = p->p_vmspace;
struct vmspace *newvmspace;
vm_ooffset_t fork_charge;
/*
* The caller is responsible for ensuring that the reference count
* cannot concurrently transition 1 -> 2.
*/
if (refcount_load(&oldvmspace->vm_refcnt) == 1)
return (0);
fork_charge = 0;
newvmspace = vmspace_fork(oldvmspace, &fork_charge);
if (newvmspace == NULL)
return (ENOMEM);
if (!swap_reserve_by_cred(fork_charge, p->p_ucred)) {
vmspace_free(newvmspace);
return (ENOMEM);
}
PROC_VMSPACE_LOCK(p);
p->p_vmspace = newvmspace;
PROC_VMSPACE_UNLOCK(p);
if (p == curthread->td_proc)
pmap_activate(curthread);
vmspace_free(oldvmspace);
return (0);
}
/*
* vm_map_lookup:
*
* Finds the VM object, offset, and
* protection for a given virtual address in the
* specified map, assuming a page fault of the
* type specified.
*
* Leaves the map in question locked for read; return
* values are guaranteed until a vm_map_lookup_done
* call is performed. Note that the map argument
* is in/out; the returned map must be used in
* the call to vm_map_lookup_done.
*
* A handle (out_entry) is returned for use in
* vm_map_lookup_done, to make that fast.
*
* If a lookup is requested with "write protection"
* specified, the map may be changed to perform virtual
* copying operations, although the data referenced will
* remain the same.
*/
int
vm_map_lookup(vm_map_t *var_map, /* IN/OUT */
vm_offset_t vaddr,
vm_prot_t fault_typea,
vm_map_entry_t *out_entry, /* OUT */
vm_object_t *object, /* OUT */
vm_pindex_t *pindex, /* OUT */
vm_prot_t *out_prot, /* OUT */
boolean_t *wired) /* OUT */
{
vm_map_entry_t entry;
vm_map_t map = *var_map;
vm_prot_t prot;
vm_prot_t fault_type;
vm_object_t eobject;
vm_size_t size;
struct ucred *cred;
RetryLookup:
vm_map_lock_read(map);
RetryLookupLocked:
/*
* Lookup the faulting address.
*/
if (!vm_map_lookup_entry(map, vaddr, out_entry)) {
vm_map_unlock_read(map);
return (KERN_INVALID_ADDRESS);
}
entry = *out_entry;
/*
* Handle submaps.
*/
if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) {
vm_map_t old_map = map;
*var_map = map = entry->object.sub_map;
vm_map_unlock_read(old_map);
goto RetryLookup;
}
/*
* Check whether this task is allowed to have this page.
*/
prot = entry->protection;
if ((fault_typea & VM_PROT_FAULT_LOOKUP) != 0) {
fault_typea &= ~VM_PROT_FAULT_LOOKUP;
if (prot == VM_PROT_NONE && map != kernel_map &&
(entry->eflags & MAP_ENTRY_GUARD) != 0 &&
(entry->eflags & (MAP_ENTRY_STACK_GAP_DN |
MAP_ENTRY_STACK_GAP_UP)) != 0 &&
vm_map_growstack(map, vaddr, entry) == KERN_SUCCESS)
goto RetryLookupLocked;
}
fault_type = fault_typea & VM_PROT_ALL;
if ((fault_type & prot) != fault_type || prot == VM_PROT_NONE) {
vm_map_unlock_read(map);
return (KERN_PROTECTION_FAILURE);
}
KASSERT((prot & VM_PROT_WRITE) == 0 || (entry->eflags &
(MAP_ENTRY_USER_WIRED | MAP_ENTRY_NEEDS_COPY)) !=
(MAP_ENTRY_USER_WIRED | MAP_ENTRY_NEEDS_COPY),
("entry %p flags %x", entry, entry->eflags));
if ((fault_typea & VM_PROT_COPY) != 0 &&
(entry->max_protection & VM_PROT_WRITE) == 0 &&
(entry->eflags & MAP_ENTRY_COW) == 0) {
vm_map_unlock_read(map);
return (KERN_PROTECTION_FAILURE);
}
/*
* If this page is not pageable, we have to get it for all possible
* accesses.
*/
*wired = (entry->wired_count != 0);
if (*wired)
fault_type = entry->protection;
size = entry->end - entry->start;
/*
* If the entry was copy-on-write, we either ...
*/
if (entry->eflags & MAP_ENTRY_NEEDS_COPY) {
/*
* If we want to write the page, we may as well handle that
* now since we've got the map locked.
*
* If we don't need to write the page, we just demote the
* permissions allowed.
*/
if ((fault_type & VM_PROT_WRITE) != 0 ||
(fault_typea & VM_PROT_COPY) != 0) {
/*
* Make a new object, and place it in the object
* chain. Note that no new references have appeared
* -- one just moved from the map to the new
* object.
*/
if (vm_map_lock_upgrade(map))
goto RetryLookup;
if (entry->cred == NULL) {
/*
* The debugger owner is charged for
* the memory.
*/
cred = curthread->td_ucred;
crhold(cred);
if (!swap_reserve_by_cred(size, cred)) {
crfree(cred);
vm_map_unlock(map);
return (KERN_RESOURCE_SHORTAGE);
}
entry->cred = cred;
}
eobject = entry->object.vm_object;
vm_object_shadow(&entry->object.vm_object,
&entry->offset, size, entry->cred, false);
if (eobject == entry->object.vm_object) {
/*
* The object was not shadowed.
*/
swap_release_by_cred(size, entry->cred);
crfree(entry->cred);
}
entry->cred = NULL;
entry->eflags &= ~MAP_ENTRY_NEEDS_COPY;
vm_map_lock_downgrade(map);
} else {
/*
* We're attempting to read a copy-on-write page --
* don't allow writes.
*/
prot &= ~VM_PROT_WRITE;
}
}
/*
* Create an object if necessary.
*/
if (entry->object.vm_object == NULL && !map->system_map) {
if (vm_map_lock_upgrade(map))
goto RetryLookup;
entry->object.vm_object = vm_object_allocate_anon(atop(size),
NULL, entry->cred, size);
entry->offset = 0;
entry->cred = NULL;
vm_map_lock_downgrade(map);
}
/*
* Return the object/offset from this entry. If the entry was
* copy-on-write or empty, it has been fixed up.
*/
*pindex = OFF_TO_IDX((vaddr - entry->start) + entry->offset);
*object = entry->object.vm_object;
*out_prot = prot;
return (KERN_SUCCESS);
}
/*
* vm_map_lookup_locked:
*
* Lookup the faulting address. A version of vm_map_lookup that returns
* KERN_FAILURE instead of blocking on map lock or memory allocation.
*/
int
vm_map_lookup_locked(vm_map_t *var_map, /* IN/OUT */
vm_offset_t vaddr,
vm_prot_t fault_typea,
vm_map_entry_t *out_entry, /* OUT */
vm_object_t *object, /* OUT */
vm_pindex_t *pindex, /* OUT */
vm_prot_t *out_prot, /* OUT */
boolean_t *wired) /* OUT */
{
vm_map_entry_t entry;
vm_map_t map = *var_map;
vm_prot_t prot;
vm_prot_t fault_type = fault_typea;
/*
* Lookup the faulting address.
*/
if (!vm_map_lookup_entry(map, vaddr, out_entry))
return (KERN_INVALID_ADDRESS);
entry = *out_entry;
/*
* Fail if the entry refers to a submap.
*/
if (entry->eflags & MAP_ENTRY_IS_SUB_MAP)
return (KERN_FAILURE);
/*
* Check whether this task is allowed to have this page.
*/
prot = entry->protection;
fault_type &= VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE;
if ((fault_type & prot) != fault_type)
return (KERN_PROTECTION_FAILURE);
/*
* If this page is not pageable, we have to get it for all possible
* accesses.
*/
*wired = (entry->wired_count != 0);
if (*wired)
fault_type = entry->protection;
if (entry->eflags & MAP_ENTRY_NEEDS_COPY) {
/*
* Fail if the entry was copy-on-write for a write fault.
*/
if (fault_type & VM_PROT_WRITE)
return (KERN_FAILURE);
/*
* We're attempting to read a copy-on-write page --
* don't allow writes.
*/
prot &= ~VM_PROT_WRITE;
}
/*
* Fail if an object should be created.
*/
if (entry->object.vm_object == NULL && !map->system_map)
return (KERN_FAILURE);
/*
* Return the object/offset from this entry. If the entry was
* copy-on-write or empty, it has been fixed up.
*/
*pindex = OFF_TO_IDX((vaddr - entry->start) + entry->offset);
*object = entry->object.vm_object;
*out_prot = prot;
return (KERN_SUCCESS);
}
/*
* vm_map_lookup_done:
*
* Releases locks acquired by a vm_map_lookup
* (according to the handle returned by that lookup).
*/
void
vm_map_lookup_done(vm_map_t map, vm_map_entry_t entry)
{
/*
* Unlock the main-level map
*/
vm_map_unlock_read(map);
}
vm_offset_t
vm_map_max_KBI(const struct vm_map *map)
{
return (vm_map_max(map));
}
vm_offset_t
vm_map_min_KBI(const struct vm_map *map)
{
return (vm_map_min(map));
}
pmap_t
vm_map_pmap_KBI(vm_map_t map)
{
return (map->pmap);
}
bool
vm_map_range_valid_KBI(vm_map_t map, vm_offset_t start, vm_offset_t end)
{
return (vm_map_range_valid(map, start, end));
}
#ifdef INVARIANTS
static void
_vm_map_assert_consistent(vm_map_t map, int check)
{
vm_map_entry_t entry, prev;
vm_map_entry_t cur, header, lbound, ubound;
vm_size_t max_left, max_right;
#ifdef DIAGNOSTIC
++map->nupdates;
#endif
if (enable_vmmap_check != check)
return;
header = prev = &map->header;
VM_MAP_ENTRY_FOREACH(entry, map) {
KASSERT(prev->end <= entry->start,
("map %p prev->end = %jx, start = %jx", map,
(uintmax_t)prev->end, (uintmax_t)entry->start));
KASSERT(entry->start < entry->end,
("map %p start = %jx, end = %jx", map,
(uintmax_t)entry->start, (uintmax_t)entry->end));
KASSERT(entry->left == header ||
entry->left->start < entry->start,
("map %p left->start = %jx, start = %jx", map,
(uintmax_t)entry->left->start, (uintmax_t)entry->start));
KASSERT(entry->right == header ||
entry->start < entry->right->start,
("map %p start = %jx, right->start = %jx", map,
(uintmax_t)entry->start, (uintmax_t)entry->right->start));
cur = map->root;
lbound = ubound = header;
for (;;) {
if (entry->start < cur->start) {
ubound = cur;
cur = cur->left;
KASSERT(cur != lbound,
("map %p cannot find %jx",
map, (uintmax_t)entry->start));
} else if (cur->end <= entry->start) {
lbound = cur;
cur = cur->right;
KASSERT(cur != ubound,
("map %p cannot find %jx",
map, (uintmax_t)entry->start));
} else {
KASSERT(cur == entry,
("map %p cannot find %jx",
map, (uintmax_t)entry->start));
break;
}
}
max_left = vm_map_entry_max_free_left(entry, lbound);
max_right = vm_map_entry_max_free_right(entry, ubound);
KASSERT(entry->max_free == vm_size_max(max_left, max_right),
("map %p max = %jx, max_left = %jx, max_right = %jx", map,
(uintmax_t)entry->max_free,
(uintmax_t)max_left, (uintmax_t)max_right));
prev = entry;
}
KASSERT(prev->end <= entry->start,
("map %p prev->end = %jx, start = %jx", map,
(uintmax_t)prev->end, (uintmax_t)entry->start));
}
#endif
#include "opt_ddb.h"
#ifdef DDB
#include <sys/kernel.h>
#include <ddb/ddb.h>
static void
vm_map_print(vm_map_t map)
{
vm_map_entry_t entry, prev;
db_iprintf("Task map %p: pmap=%p, nentries=%d, version=%u\n",
(void *)map,
(void *)map->pmap, map->nentries, map->timestamp);
db_indent += 2;
prev = &map->header;
VM_MAP_ENTRY_FOREACH(entry, map) {
db_iprintf("map entry %p: start=%p, end=%p, eflags=%#x, \n",
(void *)entry, (void *)entry->start, (void *)entry->end,
entry->eflags);
{
static const char * const inheritance_name[4] =
{"share", "copy", "none", "donate_copy"};
db_iprintf(" prot=%x/%x/%s",
entry->protection,
entry->max_protection,
inheritance_name[(int)(unsigned char)
entry->inheritance]);
if (entry->wired_count != 0)
db_printf(", wired");
}
if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) {
db_printf(", share=%p, offset=0x%jx\n",
(void *)entry->object.sub_map,
(uintmax_t)entry->offset);
if (prev == &map->header ||
prev->object.sub_map !=
entry->object.sub_map) {
db_indent += 2;
vm_map_print((vm_map_t)entry->object.sub_map);
db_indent -= 2;
}
} else {
if (entry->cred != NULL)
db_printf(", ruid %d", entry->cred->cr_ruid);
db_printf(", object=%p, offset=0x%jx",
(void *)entry->object.vm_object,
(uintmax_t)entry->offset);
if (entry->object.vm_object && entry->object.vm_object->cred)
db_printf(", obj ruid %d charge %jx",
entry->object.vm_object->cred->cr_ruid,
(uintmax_t)entry->object.vm_object->charge);
if (entry->eflags & MAP_ENTRY_COW)
db_printf(", copy (%s)",
(entry->eflags & MAP_ENTRY_NEEDS_COPY) ? "needed" : "done");
db_printf("\n");
if (prev == &map->header ||
prev->object.vm_object !=
entry->object.vm_object) {
db_indent += 2;
vm_object_print((db_expr_t)(intptr_t)
entry->object.vm_object,
0, 0, (char *)0);
db_indent -= 2;
}
}
prev = entry;
}
db_indent -= 2;
}
DB_SHOW_COMMAND(map, map)
{
if (!have_addr) {
db_printf("usage: show map <addr>\n");
return;
}
vm_map_print((vm_map_t)addr);
}
DB_SHOW_COMMAND(procvm, procvm)
{
struct proc *p;
if (have_addr) {
p = db_lookup_proc(addr);
} else {
p = curproc;
}
db_printf("p = %p, vmspace = %p, map = %p, pmap = %p\n",
(void *)p, (void *)p->p_vmspace, (void *)&p->p_vmspace->vm_map,
(void *)vmspace_pmap(p->p_vmspace));
vm_map_print((vm_map_t)&p->p_vmspace->vm_map);
}
#endif /* DDB */
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