Initial source

1 files changed, 1072 insertions, 0 deletions

diff --git a/vm/vm_kern.c b/vm/vm_kern.c
new file mode 100644
index 0000000..eb1e079
--- /dev/null
+++ b/vm/vm_kern.c
@@ -0,0 +1,1072 @@
+/*
+ * Mach Operating System
+ * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University.
+ * Copyright (c) 1993,1994 The University of Utah and
+ * the Computer Systems Laboratory (CSL).
+ * All rights reserved.
+ *
+ * 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, THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF
+ * THIS SOFTWARE IN ITS "AS IS" CONDITION, AND DISCLAIM 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 Mellon
+ * the rights to redistribute these changes.
+ */
+/*
+ *	File:	vm/vm_kern.c
+ *	Author:	Avadis Tevanian, Jr., Michael Wayne Young
+ *	Date:	1985
+ *
+ *	Kernel memory management.
+ */
+
+#include <mach/kern_return.h>
+#include "vm_param.h"
+#include <kern/assert.h>
+#include <kern/lock.h>
+#include <kern/thread.h>
+#include <vm/vm_fault.h>
+#include <vm/vm_kern.h>
+#include <vm/vm_map.h>
+#include <vm/vm_object.h>
+#include <vm/vm_page.h>
+#include <vm/vm_pageout.h>
+
+
+
+/*
+ *	Variables exported by this module.
+ */
+
+vm_map_t	kernel_map;
+vm_map_t	kernel_pageable_map;
+
+extern void kmem_alloc_pages();
+extern void kmem_remap_pages();
+
+/*
+ *	projected_buffer_allocate
+ *
+ *	Allocate a wired-down buffer shared between kernel and user task.  
+ *      Fresh, zero-filled memory is allocated.
+ *      If persistence is false, this buffer can only be deallocated from
+ *      user task using projected_buffer_deallocate, and deallocation 
+ *      from user task also deallocates the buffer from the kernel map.
+ *      projected_buffer_collect is called from vm_map_deallocate to
+ *      automatically deallocate projected buffers on task_deallocate.
+ *      Sharing with more than one user task is achieved by using 
+ *      projected_buffer_map for the second and subsequent tasks.
+ *      The user is precluded from manipulating the VM entry of this buffer
+ *      (i.e. changing protection, inheritance or machine attributes).
+ */
+
+kern_return_t
+projected_buffer_allocate(map, size, persistence, kernel_p, 
+                          user_p, protection, inheritance)
+	vm_map_t map;
+	vm_size_t size;
+        int persistence;
+	vm_offset_t *kernel_p;
+	vm_offset_t *user_p;
+        vm_prot_t protection;
+        vm_inherit_t inheritance;  /*Currently only VM_INHERIT_NONE supported*/
+{
+	vm_object_t object;
+	vm_map_entry_t u_entry, k_entry;
+	vm_offset_t addr;
+	vm_size_t r_size;
+	kern_return_t kr;
+
+	if (map == VM_MAP_NULL || map == kernel_map)
+	  return(KERN_INVALID_ARGUMENT);
+
+	/*
+	 *	Allocate a new object. 
+	 */
+
+	size = round_page(size);
+	object = vm_object_allocate(size);
+
+	vm_map_lock(kernel_map);
+	kr = vm_map_find_entry(kernel_map, &addr, size, (vm_offset_t) 0,
+			       VM_OBJECT_NULL, &k_entry);
+	if (kr != KERN_SUCCESS) {
+	  vm_map_unlock(kernel_map);
+	  vm_object_deallocate(object);
+	  return kr;
+	}
+
+	k_entry->object.vm_object = object;
+	if (!persistence)
+	  k_entry->projected_on = (vm_map_entry_t) -1;
+              /*Mark entry so as to automatically deallocate it when
+                last corresponding user entry is deallocated*/
+	vm_map_unlock(kernel_map);
+	*kernel_p = addr;
+
+	vm_map_lock(map);
+	kr = vm_map_find_entry(map, &addr, size, (vm_offset_t) 0,
+			       VM_OBJECT_NULL, &u_entry);
+	if (kr != KERN_SUCCESS) {
+	  vm_map_unlock(map);
+	  vm_map_lock(kernel_map);
+	  vm_map_entry_delete(kernel_map, k_entry);
+	  vm_map_unlock(kernel_map);
+	  vm_object_deallocate(object);
+	  return kr;
+	}
+
+	u_entry->object.vm_object = object;
+	vm_object_reference(object);
+	u_entry->projected_on = k_entry;
+             /*Creates coupling with kernel mapping of the buffer, and
+               also guarantees that user cannot directly manipulate
+               buffer VM entry*/
+	u_entry->protection = protection;
+	u_entry->max_protection = protection;
+	u_entry->inheritance = inheritance;
+	vm_map_unlock(map);
+       	*user_p = addr;
+
+	/*
+	 *	Allocate wired-down memory in the object,
+	 *	and enter it in the kernel pmap.
+	 */
+	kmem_alloc_pages(object, 0,
+			 *kernel_p, *kernel_p + size,
+			 VM_PROT_READ | VM_PROT_WRITE);
+	bzero(*kernel_p, size);         /*Zero fill*/
+
+	/* Set up physical mappings for user pmap */
+
+	pmap_pageable(map->pmap, *user_p, *user_p + size, FALSE);
+	for (r_size = 0; r_size < size; r_size += PAGE_SIZE) {
+	  addr = pmap_extract(kernel_pmap, *kernel_p + r_size);
+	  pmap_enter(map->pmap, *user_p + r_size, addr,
+		     protection, TRUE);
+	}
+
+	return(KERN_SUCCESS);
+}
+
+
+/*
+ *	projected_buffer_map
+ *
+ *	Map an area of kernel memory onto a task's address space.
+ *      No new memory is allocated; the area must previously exist in the
+ *      kernel memory map.
+ */
+
+kern_return_t
+projected_buffer_map(map, kernel_addr, size, user_p, protection, inheritance)
+	vm_map_t map;
+	vm_offset_t kernel_addr;
+	vm_size_t size;
+	vm_offset_t *user_p;
+        vm_prot_t protection;
+        vm_inherit_t inheritance;  /*Currently only VM_INHERIT_NONE supported*/
+{
+	vm_object_t object;
+	vm_map_entry_t u_entry, k_entry;
+	vm_offset_t physical_addr, user_addr;
+	vm_size_t r_size;
+	kern_return_t kr;
+
+	/*
+	 *	Find entry in kernel map 
+	 */
+
+	size = round_page(size);
+	if (map == VM_MAP_NULL || map == kernel_map ||
+	    !vm_map_lookup_entry(kernel_map, kernel_addr, &k_entry) ||
+	    kernel_addr + size > k_entry->vme_end)
+	  return(KERN_INVALID_ARGUMENT);
+
+
+	/*
+         *     Create entry in user task
+         */
+
+	vm_map_lock(map);
+	kr = vm_map_find_entry(map, &user_addr, size, (vm_offset_t) 0,
+			       VM_OBJECT_NULL, &u_entry);
+	if (kr != KERN_SUCCESS) {
+	  vm_map_unlock(map);
+	  return kr;
+	}
+
+	u_entry->object.vm_object = k_entry->object.vm_object;
+	vm_object_reference(k_entry->object.vm_object);
+	u_entry->offset = kernel_addr - k_entry->vme_start + k_entry->offset;
+	u_entry->projected_on = k_entry;
+             /*Creates coupling with kernel mapping of the buffer, and
+               also guarantees that user cannot directly manipulate
+               buffer VM entry*/
+	u_entry->protection = protection;
+	u_entry->max_protection = protection;
+	u_entry->inheritance = inheritance;
+	u_entry->wired_count = k_entry->wired_count;
+	vm_map_unlock(map);
+       	*user_p = user_addr;
+
+	/* Set up physical mappings for user pmap */
+
+	pmap_pageable(map->pmap, user_addr, user_addr + size,
+		      !k_entry->wired_count);
+	for (r_size = 0; r_size < size; r_size += PAGE_SIZE) {
+	  physical_addr = pmap_extract(kernel_pmap, kernel_addr + r_size);
+	  pmap_enter(map->pmap, user_addr + r_size, physical_addr,
+		     protection, k_entry->wired_count);
+	}
+
+	return(KERN_SUCCESS);
+}
+
+
+/*
+ *	projected_buffer_deallocate
+ *
+ *	Unmap projected buffer from task's address space.
+ *      May also unmap buffer from kernel map, if buffer is not
+ *      persistent and only the kernel reference remains.
+ */
+
+kern_return_t
+projected_buffer_deallocate(map, start, end)
+     vm_map_t map;
+     vm_offset_t start, end;
+{
+	vm_map_entry_t entry, k_entry;
+
+	vm_map_lock(map);
+     	if (map == VM_MAP_NULL || map == kernel_map ||
+	    !vm_map_lookup_entry(map, start, &entry) ||
+	    end > entry->vme_end ||
+            /*Check corresponding kernel entry*/
+	    (k_entry = entry->projected_on) == 0) {
+	  vm_map_unlock(map);
+	  return(KERN_INVALID_ARGUMENT);
+	}
+
+	/*Prepare for deallocation*/
+	if (entry->vme_start < start)
+	  _vm_map_clip_start(map, entry, start);
+	if (entry->vme_end > end)
+	  _vm_map_clip_end(map, entry, end);
+      	if (map->first_free == entry)   /*Adjust first_free hint*/
+	  map->first_free = entry->vme_prev;
+	entry->projected_on = 0;        /*Needed to allow deletion*/
+	entry->wired_count = 0;         /*Avoid unwire fault*/
+	vm_map_entry_delete(map, entry);
+	vm_map_unlock(map);
+
+	/*Check if the buffer is not persistent and only the 
+          kernel mapping remains, and if so delete it*/
+	vm_map_lock(kernel_map);
+	if (k_entry->projected_on == (vm_map_entry_t) -1 &&
+	    k_entry->object.vm_object->ref_count == 1) {
+	  if (kernel_map->first_free == k_entry)
+	    kernel_map->first_free = k_entry->vme_prev;
+	  k_entry->projected_on = 0;    /*Allow unwire fault*/
+	  vm_map_entry_delete(kernel_map, k_entry);
+	}
+	vm_map_unlock(kernel_map);
+	return(KERN_SUCCESS);
+}
+
+
+/*
+ *	projected_buffer_collect
+ *
+ *	Unmap all projected buffers from task's address space.
+ */
+
+kern_return_t
+projected_buffer_collect(map)
+        vm_map_t map;
+{
+        vm_map_entry_t entry, next;
+
+        if (map == VM_MAP_NULL || map == kernel_map)
+	  return(KERN_INVALID_ARGUMENT);
+
+	for (entry = vm_map_first_entry(map);
+	     entry != vm_map_to_entry(map);
+	     entry = next) {
+	  next = entry->vme_next;
+	  if (entry->projected_on != 0)
+	    projected_buffer_deallocate(map, entry->vme_start, entry->vme_end);
+	}
+	return(KERN_SUCCESS);
+}
+
+
+/*
+ *	projected_buffer_in_range
+ *
+ *	Verifies whether a projected buffer exists in the address range 
+ *      given.
+ */
+
+boolean_t
+projected_buffer_in_range(map, start, end)
+        vm_map_t map;
+        vm_offset_t start, end;
+{
+        vm_map_entry_t entry;
+
+        if (map == VM_MAP_NULL || map == kernel_map)
+	  return(FALSE);
+
+	/*Find first entry*/
+	if (!vm_map_lookup_entry(map, start, &entry))
+	  entry = entry->vme_next;
+
+	while (entry != vm_map_to_entry(map) && entry->projected_on == 0 &&
+	       entry->vme_start <= end) {
+	  entry = entry->vme_next;
+	}
+	return(entry != vm_map_to_entry(map) && entry->vme_start <= end);
+}
+
+
+/*
+ *	kmem_alloc:
+ *
+ *	Allocate wired-down memory in the kernel's address map
+ *	or a submap.  The memory is not zero-filled.
+ */
+
+kern_return_t
+kmem_alloc(map, addrp, size)
+	vm_map_t map;
+	vm_offset_t *addrp;
+	vm_size_t size;
+{
+	vm_object_t object;
+	vm_map_entry_t entry;
+	vm_offset_t addr;
+	kern_return_t kr;
+
+	/*
+	 *	Allocate a new object.  We must do this before locking
+	 *	the map, lest we risk deadlock with the default pager:
+	 *		device_read_alloc uses kmem_alloc,
+	 *		which tries to allocate an object,
+	 *		which uses kmem_alloc_wired to get memory,
+	 *		which blocks for pages.
+	 *		then the default pager needs to read a block
+	 *		to process a memory_object_data_write,
+	 *		and device_read_alloc calls kmem_alloc
+	 *		and deadlocks on the map lock.
+	 */
+
+	size = round_page(size);
+	object = vm_object_allocate(size);
+
+	vm_map_lock(map);
+	kr = vm_map_find_entry(map, &addr, size, (vm_offset_t) 0,
+			       VM_OBJECT_NULL, &entry);
+	if (kr != KERN_SUCCESS) {
+		vm_map_unlock(map);
+		vm_object_deallocate(object);
+		return kr;
+	}
+
+	entry->object.vm_object = object;
+	entry->offset = 0;
+
+	/*
+	 *	Since we have not given out this address yet,
+	 *	it is safe to unlock the map.
+	 */
+	vm_map_unlock(map);
+
+	/*
+	 *	Allocate wired-down memory in the kernel_object,
+	 *	for this entry, and enter it in the kernel pmap.
+	 */
+	kmem_alloc_pages(object, 0,
+			 addr, addr + size,
+			 VM_PROT_DEFAULT);
+
+	/*
+	 *	Return the memory, not zeroed.
+	 */
+	*addrp = addr;
+	return KERN_SUCCESS;
+}
+
+/*
+ *	kmem_realloc:
+ *
+ *	Reallocate wired-down memory in the kernel's address map
+ *	or a submap.  Newly allocated pages are not zeroed.
+ *	This can only be used on regions allocated with kmem_alloc.
+ *
+ *	If successful, the pages in the old region are mapped twice.
+ *	The old region is unchanged.  Use kmem_free to get rid of it.
+ */
+kern_return_t kmem_realloc(map, oldaddr, oldsize, newaddrp, newsize)
+	vm_map_t map;
+	vm_offset_t oldaddr;
+	vm_size_t oldsize;
+	vm_offset_t *newaddrp;
+	vm_size_t newsize;
+{
+	vm_offset_t oldmin, oldmax;
+	vm_offset_t newaddr;
+	vm_object_t object;
+	vm_map_entry_t oldentry, newentry;
+	kern_return_t kr;
+
+	oldmin = trunc_page(oldaddr);
+	oldmax = round_page(oldaddr + oldsize);
+	oldsize = oldmax - oldmin;
+	newsize = round_page(newsize);
+
+	/*
+	 *	Find space for the new region.
+	 */
+
+	vm_map_lock(map);
+	kr = vm_map_find_entry(map, &newaddr, newsize, (vm_offset_t) 0,
+			       VM_OBJECT_NULL, &newentry);
+	if (kr != KERN_SUCCESS) {
+		vm_map_unlock(map);
+		return kr;
+	}
+
+	/*
+	 *	Find the VM object backing the old region.
+	 */
+
+	if (!vm_map_lookup_entry(map, oldmin, &oldentry))
+		panic("kmem_realloc");
+	object = oldentry->object.vm_object;
+
+	/*
+	 *	Increase the size of the object and
+	 *	fill in the new region.
+	 */
+
+	vm_object_reference(object);
+	vm_object_lock(object);
+	if (object->size != oldsize)
+		panic("kmem_realloc");
+	object->size = newsize;
+	vm_object_unlock(object);
+
+	newentry->object.vm_object = object;
+	newentry->offset = 0;
+
+	/*
+	 *	Since we have not given out this address yet,
+	 *	it is safe to unlock the map.  We are trusting
+	 *	that nobody will play with either region.
+	 */
+
+	vm_map_unlock(map);
+
+	/*
+	 *	Remap the pages in the old region and
+	 *	allocate more pages for the new region.
+	 */
+
+	kmem_remap_pages(object, 0,
+			 newaddr, newaddr + oldsize,
+			 VM_PROT_DEFAULT);
+	kmem_alloc_pages(object, oldsize,
+			 newaddr + oldsize, newaddr + newsize,
+			 VM_PROT_DEFAULT);
+
+	*newaddrp = newaddr;
+	return KERN_SUCCESS;
+}
+
+/*
+ *	kmem_alloc_wired:
+ *
+ *	Allocate wired-down memory in the kernel's address map
+ *	or a submap.  The memory is not zero-filled.
+ *
+ *	The memory is allocated in the kernel_object.
+ *	It may not be copied with vm_map_copy, and
+ *	it may not be reallocated with kmem_realloc.
+ */
+
+kern_return_t
+kmem_alloc_wired(map, addrp, size)
+	vm_map_t map;
+	vm_offset_t *addrp;
+	vm_size_t size;
+{
+	vm_map_entry_t entry;
+	vm_offset_t offset;
+	vm_offset_t addr;
+	kern_return_t kr;
+
+	/*
+	 *	Use the kernel object for wired-down kernel pages.
+	 *	Assume that no region of the kernel object is
+	 *	referenced more than once.  We want vm_map_find_entry
+	 *	to extend an existing entry if possible.
+	 */
+
+	size = round_page(size);
+	vm_map_lock(map);
+	kr = vm_map_find_entry(map, &addr, size, (vm_offset_t) 0,
+			       kernel_object, &entry);
+	if (kr != KERN_SUCCESS) {
+		vm_map_unlock(map);
+		return kr;
+	}
+
+	/*
+	 *	Since we didn't know where the new region would
+	 *	start, we couldn't supply the correct offset into
+	 *	the kernel object.  We only initialize the entry
+	 *	if we aren't extending an existing entry.
+	 */
+
+	offset = addr - VM_MIN_KERNEL_ADDRESS;
+
+	if (entry->object.vm_object == VM_OBJECT_NULL) {
+		vm_object_reference(kernel_object);
+
+		entry->object.vm_object = kernel_object;
+		entry->offset = offset;
+	}
+
+	/*
+	 *	Since we have not given out this address yet,
+	 *	it is safe to unlock the map.
+	 */
+	vm_map_unlock(map);
+
+	/*
+	 *	Allocate wired-down memory in the kernel_object,
+	 *	for this entry, and enter it in the kernel pmap.
+	 */
+	kmem_alloc_pages(kernel_object, offset,
+			 addr, addr + size,
+			 VM_PROT_DEFAULT);
+
+	/*
+	 *	Return the memory, not zeroed.
+	 */
+	*addrp = addr;
+	return KERN_SUCCESS;
+}
+
+/*
+ *	kmem_alloc_aligned:
+ *
+ *	Like kmem_alloc_wired, except that the memory is aligned.
+ *	The size should be a power-of-2.
+ */
+
+kern_return_t
+kmem_alloc_aligned(map, addrp, size)
+	vm_map_t map;
+	vm_offset_t *addrp;
+	vm_size_t size;
+{
+	vm_map_entry_t entry;
+	vm_offset_t offset;
+	vm_offset_t addr;
+	kern_return_t kr;
+
+	if ((size & (size - 1)) != 0)
+		panic("kmem_alloc_aligned");
+
+	/*
+	 *	Use the kernel object for wired-down kernel pages.
+	 *	Assume that no region of the kernel object is
+	 *	referenced more than once.  We want vm_map_find_entry
+	 *	to extend an existing entry if possible.
+	 */
+
+	size = round_page(size);
+	vm_map_lock(map);
+	kr = vm_map_find_entry(map, &addr, size, size - 1,
+			       kernel_object, &entry);
+	if (kr != KERN_SUCCESS) {
+		vm_map_unlock(map);
+		return kr;
+	}
+
+	/*
+	 *	Since we didn't know where the new region would
+	 *	start, we couldn't supply the correct offset into
+	 *	the kernel object.  We only initialize the entry
+	 *	if we aren't extending an existing entry.
+	 */
+
+	offset = addr - VM_MIN_KERNEL_ADDRESS;
+
+	if (entry->object.vm_object == VM_OBJECT_NULL) {
+		vm_object_reference(kernel_object);
+
+		entry->object.vm_object = kernel_object;
+		entry->offset = offset;
+	}
+
+	/*
+	 *	Since we have not given out this address yet,
+	 *	it is safe to unlock the map.
+	 */
+	vm_map_unlock(map);
+
+	/*
+	 *	Allocate wired-down memory in the kernel_object,
+	 *	for this entry, and enter it in the kernel pmap.
+	 */
+	kmem_alloc_pages(kernel_object, offset,
+			 addr, addr + size,
+			 VM_PROT_DEFAULT);
+
+	/*
+	 *	Return the memory, not zeroed.
+	 */
+	*addrp = addr;
+	return KERN_SUCCESS;
+}
+
+/*
+ *	kmem_alloc_pageable:
+ *
+ *	Allocate pageable memory in the kernel's address map.
+ */
+
+kern_return_t
+kmem_alloc_pageable(map, addrp, size)
+	vm_map_t map;
+	vm_offset_t *addrp;
+	vm_size_t size;
+{
+	vm_offset_t addr;
+	kern_return_t kr;
+
+	addr = vm_map_min(map);
+	kr = vm_map_enter(map, &addr, round_page(size),
+			  (vm_offset_t) 0, TRUE,
+			  VM_OBJECT_NULL, (vm_offset_t) 0, FALSE,
+			  VM_PROT_DEFAULT, VM_PROT_ALL, VM_INHERIT_DEFAULT);
+	if (kr != KERN_SUCCESS)
+		return kr;
+
+	*addrp = addr;
+	return KERN_SUCCESS;
+}
+
+/*
+ *	kmem_free:
+ *
+ *	Release a region of kernel virtual memory allocated
+ *	with kmem_alloc, kmem_alloc_wired, or kmem_alloc_pageable,
+ *	and return the physical pages associated with that region.
+ */
+
+void
+kmem_free(map, addr, size)
+	vm_map_t map;
+	vm_offset_t addr;
+	vm_size_t size;
+{
+	kern_return_t kr;
+
+	kr = vm_map_remove(map, trunc_page(addr), round_page(addr + size));
+	if (kr != KERN_SUCCESS)
+		panic("kmem_free");
+}
+
+/*
+ *	Allocate new wired pages in an object.
+ *	The object is assumed to be mapped into the kernel map or
+ *	a submap.
+ */
+void
+kmem_alloc_pages(object, offset, start, end, protection)
+	register vm_object_t	object;
+	register vm_offset_t	offset;
+	register vm_offset_t	start, end;
+	vm_prot_t		protection;
+{
+	/*
+	 *	Mark the pmap region as not pageable.
+	 */
+	pmap_pageable(kernel_pmap, start, end, FALSE);
+
+	while (start < end) {
+	    register vm_page_t	mem;
+
+	    vm_object_lock(object);
+
+	    /*
+	     *	Allocate a page
+	     */
+	    while ((mem = vm_page_alloc(object, offset))
+			 == VM_PAGE_NULL) {
+		vm_object_unlock(object);
+		VM_PAGE_WAIT((void (*)()) 0);
+		vm_object_lock(object);
+	    }
+
+	    /*
+	     *	Wire it down
+	     */
+	    vm_page_lock_queues();
+	    vm_page_wire(mem);
+	    vm_page_unlock_queues();
+	    vm_object_unlock(object);
+
+	    /*
+	     *	Enter it in the kernel pmap
+	     */
+	    PMAP_ENTER(kernel_pmap, start, mem,
+		       protection, TRUE);
+
+	    vm_object_lock(object);
+	    PAGE_WAKEUP_DONE(mem);
+	    vm_object_unlock(object);
+
+	    start += PAGE_SIZE;
+	    offset += PAGE_SIZE;
+	}
+}
+
+/*
+ *	Remap wired pages in an object into a new region.
+ *	The object is assumed to be mapped into the kernel map or
+ *	a submap.
+ */
+void
+kmem_remap_pages(object, offset, start, end, protection)
+	register vm_object_t	object;
+	register vm_offset_t	offset;
+	register vm_offset_t	start, end;
+	vm_prot_t		protection;
+{
+	/*
+	 *	Mark the pmap region as not pageable.
+	 */
+	pmap_pageable(kernel_pmap, start, end, FALSE);
+
+	while (start < end) {
+	    register vm_page_t	mem;
+
+	    vm_object_lock(object);
+
+	    /*
+	     *	Find a page
+	     */
+	    if ((mem = vm_page_lookup(object, offset)) == VM_PAGE_NULL)
+		panic("kmem_remap_pages");
+
+	    /*
+	     *	Wire it down (again)
+	     */
+	    vm_page_lock_queues();
+	    vm_page_wire(mem);
+	    vm_page_unlock_queues();
+	    vm_object_unlock(object);
+
+	    /*
+	     *	Enter it in the kernel pmap.  The page isn't busy,
+	     *	but this shouldn't be a problem because it is wired.
+	     */
+	    PMAP_ENTER(kernel_pmap, start, mem,
+		       protection, TRUE);
+
+	    start += PAGE_SIZE;
+	    offset += PAGE_SIZE;
+	}
+}
+
+/*
+ *	kmem_suballoc:
+ *
+ *	Allocates a map to manage a subrange
+ *	of the kernel virtual address space.
+ *
+ *	Arguments are as follows:
+ *
+ *	parent		Map to take range from
+ *	size		Size of range to find
+ *	min, max	Returned endpoints of map
+ *	pageable	Can the region be paged
+ */
+
+vm_map_t
+kmem_suballoc(parent, min, max, size, pageable)
+	vm_map_t parent;
+	vm_offset_t *min, *max;
+	vm_size_t size;
+	boolean_t pageable;
+{
+	vm_map_t map;
+	vm_offset_t addr;
+	kern_return_t kr;
+
+	size = round_page(size);
+
+	/*
+	 *	Need reference on submap object because it is internal
+	 *	to the vm_system.  vm_object_enter will never be called
+	 *	on it (usual source of reference for vm_map_enter).
+	 */
+	vm_object_reference(vm_submap_object);
+
+	addr = (vm_offset_t) vm_map_min(parent);
+	kr = vm_map_enter(parent, &addr, size,
+			  (vm_offset_t) 0, TRUE,
+			  vm_submap_object, (vm_offset_t) 0, FALSE,
+			  VM_PROT_DEFAULT, VM_PROT_ALL, VM_INHERIT_DEFAULT);
+	if (kr != KERN_SUCCESS)
+		panic("kmem_suballoc");
+
+	pmap_reference(vm_map_pmap(parent));
+	map = vm_map_create(vm_map_pmap(parent), addr, addr + size, pageable);
+	if (map == VM_MAP_NULL)
+		panic("kmem_suballoc");
+
+	kr = vm_map_submap(parent, addr, addr + size, map);
+	if (kr != KERN_SUCCESS)
+		panic("kmem_suballoc");
+
+	*min = addr;
+	*max = addr + size;
+	return map;
+}
+
+/*
+ *	kmem_init:
+ *
+ *	Initialize the kernel's virtual memory map, taking
+ *	into account all memory allocated up to this time.
+ */
+void kmem_init(start, end)
+	vm_offset_t	start;
+	vm_offset_t	end;
+{
+	kernel_map = vm_map_create(pmap_kernel(),
+				   VM_MIN_KERNEL_ADDRESS, end,
+				   FALSE);
+
+	/*
+	 *	Reserve virtual memory allocated up to this time.
+	 */
+
+	if (start != VM_MIN_KERNEL_ADDRESS) {
+		kern_return_t rc;
+		vm_offset_t addr = VM_MIN_KERNEL_ADDRESS;
+		rc = vm_map_enter(kernel_map,
+				  &addr, start - VM_MIN_KERNEL_ADDRESS,
+				  (vm_offset_t) 0, TRUE,
+				  VM_OBJECT_NULL, (vm_offset_t) 0, FALSE,
+				  VM_PROT_DEFAULT, VM_PROT_ALL,
+				  VM_INHERIT_DEFAULT);
+		if (rc)
+			panic("%s:%d: vm_map_enter failed (%d)\n", rc);
+	}
+}
+
+/*
+ *	New and improved IO wiring support.
+ */
+
+/*
+ *	kmem_io_map_copyout:
+ *
+ *	Establish temporary mapping in designated map for the memory
+ *	passed in.  Memory format must be a page_list vm_map_copy.
+ *	Mapping is READ-ONLY.
+ */
+
+kern_return_t
+kmem_io_map_copyout(map, addr, alloc_addr, alloc_size, copy, min_size)
+     vm_map_t 		map;
+     vm_offset_t	*addr;  	/* actual addr of data */
+     vm_offset_t	*alloc_addr;	/* page aligned addr */
+     vm_size_t		*alloc_size;	/* size allocated */
+     vm_map_copy_t	copy;
+     vm_size_t		min_size;	/* Do at least this much */
+{
+	vm_offset_t	myaddr, offset;
+	vm_size_t	mysize, copy_size;
+	kern_return_t	ret;
+	register
+	vm_page_t	*page_list;
+	vm_map_copy_t	new_copy;
+	register
+	int		i;
+
+	assert(copy->type == VM_MAP_COPY_PAGE_LIST);
+	assert(min_size != 0);
+
+	/*
+	 *	Figure out the size in vm pages.
+	 */
+	min_size += copy->offset - trunc_page(copy->offset);
+	min_size = round_page(min_size);
+	mysize = round_page(copy->offset + copy->size) -
+		trunc_page(copy->offset);
+
+	/*
+	 *	If total size is larger than one page list and
+	 *	we don't have to do more than one page list, then
+	 *	only do one page list.  
+	 *
+	 * XXX	Could be much smarter about this ... like trimming length
+	 * XXX	if we need more than one page list but not all of them.
+	 */
+
+	copy_size = ptoa(copy->cpy_npages);
+	if (mysize > copy_size && copy_size > min_size)
+		mysize = copy_size;
+
+	/*
+	 *	Allocate some address space in the map (must be kernel
+	 *	space).
+	 */
+	myaddr = vm_map_min(map);
+	ret = vm_map_enter(map, &myaddr, mysize,
+			  (vm_offset_t) 0, TRUE,
+			  VM_OBJECT_NULL, (vm_offset_t) 0, FALSE,
+			  VM_PROT_DEFAULT, VM_PROT_ALL, VM_INHERIT_DEFAULT);
+
+	if (ret != KERN_SUCCESS)
+		return(ret);
+
+	/*
+	 *	Tell the pmap module that this will be wired, and
+	 *	enter the mappings.
+	 */
+	pmap_pageable(vm_map_pmap(map), myaddr, myaddr + mysize, TRUE);
+
+	*addr = myaddr + (copy->offset - trunc_page(copy->offset));
+	*alloc_addr = myaddr;
+	*alloc_size = mysize;
+
+	offset = myaddr;
+	page_list = &copy->cpy_page_list[0];
+	while (TRUE) {
+		for ( i = 0; i < copy->cpy_npages; i++, offset += PAGE_SIZE) {
+			PMAP_ENTER(vm_map_pmap(map), offset, *page_list,
+				   VM_PROT_READ, TRUE);
+			page_list++;
+		}
+
+		if (offset == (myaddr + mysize))
+			break;
+
+		/*
+		 *	Onward to the next page_list.  The extend_cont
+		 *	leaves the current page list's pages alone; 
+		 *	they'll be cleaned up at discard.  Reset this
+		 *	copy's continuation to discard the next one.
+		 */
+		vm_map_copy_invoke_extend_cont(copy, &new_copy, &ret);
+
+		if (ret != KERN_SUCCESS) {
+			kmem_io_map_deallocate(map, myaddr, mysize);
+			return(ret);
+		}
+		copy->cpy_cont = vm_map_copy_discard_cont;
+		copy->cpy_cont_args = (char *) new_copy;
+		copy = new_copy;
+		page_list = &copy->cpy_page_list[0];
+	}
+
+	return(ret);
+}
+
+/*
+ *	kmem_io_map_deallocate:
+ *
+ *	Get rid of the mapping established by kmem_io_map_copyout.
+ *	Assumes that addr and size have been rounded to page boundaries.
+ *	(e.g., the alloc_addr and alloc_size returned by kmem_io_map_copyout)
+ */
+
+void
+kmem_io_map_deallocate(map, addr, size)
+	vm_map_t	map;
+	vm_offset_t	addr;
+	vm_size_t	size;
+{
+	/*
+	 *	Remove the mappings.  The pmap_remove is needed.
+	 */
+	
+	pmap_remove(vm_map_pmap(map), addr, addr + size);
+	vm_map_remove(map, addr, addr + size);
+}
+
+/*
+ *	Routine:	copyinmap
+ *	Purpose:
+ *		Like copyin, except that fromaddr is an address
+ *		in the specified VM map.  This implementation
+ *		is incomplete; it handles the current user map
+ *		and the kernel map/submaps.
+ */
+
+int copyinmap(map, fromaddr, toaddr, length)
+	vm_map_t map;
+	char *fromaddr, *toaddr;
+	int length;
+{
+	if (vm_map_pmap(map) == kernel_pmap) {
+		/* assume a correct copy */
+		bcopy(fromaddr, toaddr, length);
+		return 0;
+	}
+
+	if (current_map() == map)
+		return copyin( fromaddr, toaddr, length);
+
+	return 1;
+}
+
+/*
+ *	Routine:	copyoutmap
+ *	Purpose:
+ *		Like copyout, except that toaddr is an address
+ *		in the specified VM map.  This implementation
+ *		is incomplete; it handles the current user map
+ *		and the kernel map/submaps.
+ */
+
+int copyoutmap(map, fromaddr, toaddr, length)
+	vm_map_t map;
+	char *fromaddr, *toaddr;
+	int length;
+{
+	if (vm_map_pmap(map) == kernel_pmap) {
+		/* assume a correct copy */
+		bcopy(fromaddr, toaddr, length);
+		return 0;
+	}
+
+	if (current_map() == map)
+		return copyout(fromaddr, toaddr, length);
+
+	return 1;
+}