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312 lines
8.0 KiB
312 lines
8.0 KiB
/*
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* c 2001 PPC 64 Team, IBM Corp
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include <asm/uaccess.h>
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#include <asm/pgalloc.h>
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#include <asm/pgtable.h>
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#include <asm/semaphore.h>
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static DECLARE_MUTEX(imlist_sem);
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struct vm_struct * imlist = NULL;
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static int get_free_im_addr(unsigned long size, unsigned long *im_addr)
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{
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unsigned long addr;
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struct vm_struct **p, *tmp;
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addr = IMALLOC_START;
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for (p = &imlist; (tmp = *p) ; p = &tmp->next) {
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if (size + addr < (unsigned long) tmp->addr)
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break;
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if ((unsigned long)tmp->addr >= IMALLOC_START)
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addr = tmp->size + (unsigned long) tmp->addr;
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if (addr > IMALLOC_END-size)
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return 1;
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}
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*im_addr = addr;
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return 0;
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}
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/* Return whether the region described by v_addr and size is a subset
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* of the region described by parent
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*/
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static inline int im_region_is_subset(unsigned long v_addr, unsigned long size,
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struct vm_struct *parent)
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{
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return (int) (v_addr >= (unsigned long) parent->addr &&
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v_addr < (unsigned long) parent->addr + parent->size &&
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size < parent->size);
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}
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/* Return whether the region described by v_addr and size is a superset
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* of the region described by child
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*/
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static int im_region_is_superset(unsigned long v_addr, unsigned long size,
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struct vm_struct *child)
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{
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struct vm_struct parent;
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parent.addr = (void *) v_addr;
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parent.size = size;
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return im_region_is_subset((unsigned long) child->addr, child->size,
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&parent);
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}
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/* Return whether the region described by v_addr and size overlaps
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* the region described by vm. Overlapping regions meet the
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* following conditions:
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* 1) The regions share some part of the address space
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* 2) The regions aren't identical
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* 3) Neither region is a subset of the other
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*/
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static int im_region_overlaps(unsigned long v_addr, unsigned long size,
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struct vm_struct *vm)
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{
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if (im_region_is_superset(v_addr, size, vm))
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return 0;
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return (v_addr + size > (unsigned long) vm->addr + vm->size &&
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v_addr < (unsigned long) vm->addr + vm->size) ||
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(v_addr < (unsigned long) vm->addr &&
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v_addr + size > (unsigned long) vm->addr);
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}
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/* Determine imalloc status of region described by v_addr and size.
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* Can return one of the following:
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* IM_REGION_UNUSED - Entire region is unallocated in imalloc space.
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* IM_REGION_SUBSET - Region is a subset of a region that is already
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* allocated in imalloc space.
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* vm will be assigned to a ptr to the parent region.
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* IM_REGION_EXISTS - Exact region already allocated in imalloc space.
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* vm will be assigned to a ptr to the existing imlist
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* member.
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* IM_REGION_OVERLAPS - Region overlaps an allocated region in imalloc space.
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* IM_REGION_SUPERSET - Region is a superset of a region that is already
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* allocated in imalloc space.
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*/
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static int im_region_status(unsigned long v_addr, unsigned long size,
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struct vm_struct **vm)
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{
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struct vm_struct *tmp;
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for (tmp = imlist; tmp; tmp = tmp->next)
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if (v_addr < (unsigned long) tmp->addr + tmp->size)
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break;
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if (tmp) {
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if (im_region_overlaps(v_addr, size, tmp))
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return IM_REGION_OVERLAP;
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*vm = tmp;
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if (im_region_is_subset(v_addr, size, tmp)) {
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/* Return with tmp pointing to superset */
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return IM_REGION_SUBSET;
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}
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if (im_region_is_superset(v_addr, size, tmp)) {
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/* Return with tmp pointing to first subset */
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return IM_REGION_SUPERSET;
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}
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else if (v_addr == (unsigned long) tmp->addr &&
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size == tmp->size) {
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/* Return with tmp pointing to exact region */
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return IM_REGION_EXISTS;
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}
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}
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*vm = NULL;
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return IM_REGION_UNUSED;
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}
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static struct vm_struct * split_im_region(unsigned long v_addr,
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unsigned long size, struct vm_struct *parent)
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{
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struct vm_struct *vm1 = NULL;
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struct vm_struct *vm2 = NULL;
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struct vm_struct *new_vm = NULL;
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vm1 = (struct vm_struct *) kmalloc(sizeof(*vm1), GFP_KERNEL);
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if (vm1 == NULL) {
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printk(KERN_ERR "%s() out of memory\n", __FUNCTION__);
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return NULL;
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}
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if (v_addr == (unsigned long) parent->addr) {
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/* Use existing parent vm_struct to represent child, allocate
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* new one for the remainder of parent range
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*/
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vm1->size = parent->size - size;
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vm1->addr = (void *) (v_addr + size);
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vm1->next = parent->next;
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parent->size = size;
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parent->next = vm1;
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new_vm = parent;
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} else if (v_addr + size == (unsigned long) parent->addr +
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parent->size) {
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/* Allocate new vm_struct to represent child, use existing
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* parent one for remainder of parent range
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*/
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vm1->size = size;
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vm1->addr = (void *) v_addr;
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vm1->next = parent->next;
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new_vm = vm1;
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parent->size -= size;
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parent->next = vm1;
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} else {
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/* Allocate two new vm_structs for the new child and
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* uppermost remainder, and use existing parent one for the
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* lower remainder of parent range
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*/
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vm2 = (struct vm_struct *) kmalloc(sizeof(*vm2), GFP_KERNEL);
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if (vm2 == NULL) {
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printk(KERN_ERR "%s() out of memory\n", __FUNCTION__);
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kfree(vm1);
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return NULL;
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}
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vm1->size = size;
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vm1->addr = (void *) v_addr;
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vm1->next = vm2;
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new_vm = vm1;
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vm2->size = ((unsigned long) parent->addr + parent->size) -
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(v_addr + size);
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vm2->addr = (void *) v_addr + size;
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vm2->next = parent->next;
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parent->size = v_addr - (unsigned long) parent->addr;
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parent->next = vm1;
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}
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return new_vm;
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}
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static struct vm_struct * __add_new_im_area(unsigned long req_addr,
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unsigned long size)
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{
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struct vm_struct **p, *tmp, *area;
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for (p = &imlist; (tmp = *p) ; p = &tmp->next) {
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if (req_addr + size <= (unsigned long)tmp->addr)
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break;
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}
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area = (struct vm_struct *) kmalloc(sizeof(*area), GFP_KERNEL);
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if (!area)
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return NULL;
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area->flags = 0;
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area->addr = (void *)req_addr;
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area->size = size;
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area->next = *p;
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*p = area;
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return area;
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}
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static struct vm_struct * __im_get_area(unsigned long req_addr,
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unsigned long size,
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int criteria)
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{
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struct vm_struct *tmp;
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int status;
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status = im_region_status(req_addr, size, &tmp);
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if ((criteria & status) == 0) {
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return NULL;
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}
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switch (status) {
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case IM_REGION_UNUSED:
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tmp = __add_new_im_area(req_addr, size);
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break;
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case IM_REGION_SUBSET:
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tmp = split_im_region(req_addr, size, tmp);
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break;
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case IM_REGION_EXISTS:
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/* Return requested region */
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break;
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case IM_REGION_SUPERSET:
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/* Return first existing subset of requested region */
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break;
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default:
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printk(KERN_ERR "%s() unexpected imalloc region status\n",
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__FUNCTION__);
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tmp = NULL;
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}
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return tmp;
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}
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struct vm_struct * im_get_free_area(unsigned long size)
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{
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struct vm_struct *area;
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unsigned long addr;
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down(&imlist_sem);
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if (get_free_im_addr(size, &addr)) {
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printk(KERN_ERR "%s() cannot obtain addr for size 0x%lx\n",
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__FUNCTION__, size);
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area = NULL;
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goto next_im_done;
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}
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area = __im_get_area(addr, size, IM_REGION_UNUSED);
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if (area == NULL) {
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printk(KERN_ERR
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"%s() cannot obtain area for addr 0x%lx size 0x%lx\n",
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__FUNCTION__, addr, size);
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}
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next_im_done:
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up(&imlist_sem);
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return area;
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}
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struct vm_struct * im_get_area(unsigned long v_addr, unsigned long size,
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int criteria)
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{
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struct vm_struct *area;
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down(&imlist_sem);
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area = __im_get_area(v_addr, size, criteria);
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up(&imlist_sem);
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return area;
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}
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unsigned long im_free(void * addr)
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{
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struct vm_struct **p, *tmp;
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unsigned long ret_size = 0;
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if (!addr)
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return ret_size;
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if ((PAGE_SIZE-1) & (unsigned long) addr) {
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printk(KERN_ERR "Trying to %s bad address (%p)\n", __FUNCTION__, addr);
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return ret_size;
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}
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down(&imlist_sem);
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for (p = &imlist ; (tmp = *p) ; p = &tmp->next) {
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if (tmp->addr == addr) {
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ret_size = tmp->size;
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*p = tmp->next;
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kfree(tmp);
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up(&imlist_sem);
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return ret_size;
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}
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}
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up(&imlist_sem);
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printk(KERN_ERR "Trying to %s nonexistent area (%p)\n", __FUNCTION__,
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addr);
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return ret_size;
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}
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