/*
* 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(
vm_object_t object,
vm_offset_t offset,
vm_offset_t start,
vm_offset_t end,
vm_prot_t protection)
{
/*
* Mark the pmap region as not pageable.
*/
pmap_pageable(kernel_pmap, start, end, FALSE);
while (start < end) {
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;
}
}
kern_return_t
kernel_memory_allocate(
register vm_map_t map,
register vm_offset_t *addrp,
register vm_size_t size,
register vm_offset_t mask,
int flags)
{
vm_object_t object;
vm_object_offset_t offset;
vm_object_offset_t pg_offset;
vm_map_entry_t entry;
vm_map_offset_t map_addr, fill_start;
vm_map_offset_t map_mask;
vm_map_size_t map_size, fill_size;
kern_return_t kr;
vm_page_t mem;
vm_page_t guard_page_list = NULL;
vm_page_t wired_page_list = NULL;
int guard_page_count = 0;
int wired_page_count = 0;
int i;
int vm_alloc_flags;
if (! vm_kernel_ready) {
panic("kernel_memory_allocate: VM is not ready");
}
if (size == 0) {
*addrp = 0;
return KERN_INVALID_ARGUMENT;
}
map_size = vm_map_round_page(size);
map_mask = (vm_map_offset_t) mask;
vm_alloc_flags = 0;
/*
* limit the size of a single extent of wired memory
* to try and limit the damage to the system if
* too many pages get wired down
*/
if (map_size > (1 << 30)) {
return KERN_RESOURCE_SHORTAGE;
}
/*
* Guard pages:
*
* Guard pages are implemented as ficticious pages. By placing guard pages
* on either end of a stack, they can help detect cases where a thread walks
* off either end of its stack. They are allocated and set up here and attempts
* to access those pages are trapped in vm_fault_page().
*
* The map_size we were passed may include extra space for
* guard pages. If those were requested, then back it out of fill_size
* since vm_map_find_space() takes just the actual size not including
* guard pages. Similarly, fill_start indicates where the actual pages
* will begin in the range.
*/
fill_start = 0;
fill_size = map_size;
if (flags & KMA_GUARD_FIRST) {
vm_alloc_flags |= VM_FLAGS_GUARD_BEFORE;
fill_start += PAGE_SIZE_64;
fill_size -= PAGE_SIZE_64;
if (map_size < fill_start + fill_size) {
/* no space for a guard page */
*addrp = 0;
return KERN_INVALID_ARGUMENT;
}
guard_page_count++;
}
if (flags & KMA_GUARD_LAST) {
vm_alloc_flags |= VM_FLAGS_GUARD_AFTER;
fill_size -= PAGE_SIZE_64;
if (map_size <= fill_start + fill_size) {
/* no space for a guard page */
*addrp = 0;
return KERN_INVALID_ARGUMENT;
}
guard_page_count++;
}
wired_page_count = (int) (fill_size / PAGE_SIZE_64);
assert(wired_page_count * PAGE_SIZE_64 == fill_size);
for (i = 0; i < guard_page_count; i++) {
for (;;) {
mem = vm_page_grab_guard();
if (mem != VM_PAGE_NULL)
break;
if (flags & KMA_NOPAGEWAIT) {
kr = KERN_RESOURCE_SHORTAGE;
goto out;
}
vm_page_more_fictitious();
}
mem->pageq.next = (queue_entry_t)guard_page_list;
guard_page_list = mem;
}
for (i = 0; i < wired_page_count; i++) {
uint64_t unavailable;
for (;;) {
if (flags & KMA_LOMEM)
mem = vm_page_grablo();
else
mem = vm_page_grab();
if (mem != VM_PAGE_NULL)
break;
if (flags & KMA_NOPAGEWAIT) {
kr = KERN_RESOURCE_SHORTAGE;
goto out;
}
if ((flags & KMA_LOMEM) && (vm_lopage_needed == TRUE)) {
kr = KERN_RESOURCE_SHORTAGE;
goto out;
}
unavailable = (vm_page_wire_count + vm_page_free_target) * PAGE_SIZE;
if (unavailable > max_mem || map_size > (max_mem - unavailable)) {
kr = KERN_RESOURCE_SHORTAGE;
goto out;
}
VM_PAGE_WAIT();
}
mem->pageq.next = (queue_entry_t)wired_page_list;
wired_page_list = mem;
}
/*
* Allocate a new object (if necessary). We must do this before
* locking the map, or risk deadlock with the default pager.
*/
if ((flags & KMA_KOBJECT) != 0) {
object = kernel_object;
vm_object_reference(object);
} else {
object = vm_object_allocate(map_size);
}
kr = vm_map_find_space(map, &map_addr,
fill_size, map_mask,
vm_alloc_flags, &entry);
if (KERN_SUCCESS != kr) {
vm_object_deallocate(object);
goto out;
}
entry->object.vm_object = object;
entry->offset = offset = (object == kernel_object) ?
map_addr : 0;
entry->wired_count++;
if (flags & KMA_PERMANENT)
entry->permanent = TRUE;
if (object != kernel_object)
vm_object_reference(object);
vm_object_lock(object);
vm_map_unlock(map);
pg_offset = 0;
if (fill_start) {
if (guard_page_list == NULL)
panic("kernel_memory_allocate: guard_page_list == NULL");
mem = guard_page_list;
guard_page_list = (vm_page_t)mem->pageq.next;
mem->pageq.next = NULL;
vm_page_insert(mem, object, offset + pg_offset);
mem->busy = FALSE;
pg_offset += PAGE_SIZE_64;
}
for (pg_offset = fill_start; pg_offset < fill_start + fill_size; pg_offset += PAGE_SIZE_64) {
if (wired_page_list == NULL)
panic("kernel_memory_allocate: wired_page_list == NULL");
mem = wired_page_list;
wired_page_list = (vm_page_t)mem->pageq.next;
mem->pageq.next = NULL;
mem->wire_count++;
vm_page_insert(mem, object, offset + pg_offset);
mem->busy = FALSE;
mem->pmapped = TRUE;
mem->wpmapped = TRUE;
PMAP_ENTER(kernel_pmap, map_addr + pg_offset, mem,
VM_PROT_READ | VM_PROT_WRITE, object->wimg_bits & VM_WIMG_MASK, TRUE);
if (flags & KMA_NOENCRYPT) {
bzero(CAST_DOWN(void *, (map_addr + pg_offset)), PAGE_SIZE);
pmap_set_noencrypt(mem->phys_page);
}
}
