-struct phys_desc {
- struct rb_node rb;
- int fd;
- __u64 offset;
- void *virt;
- unsigned long phys;
- struct list_head list;
-};
-
-static struct rb_root phys_mappings = RB_ROOT;
-
-static struct rb_node **find_rb(void *virt)
-{
- struct rb_node **n = &phys_mappings.rb_node;
- struct phys_desc *d;
-
- while(*n != NULL){
- d = rb_entry(*n, struct phys_desc, rb);
- if(d->virt == virt)
- return n;
-
- if(d->virt > virt)
- n = &(*n)->rb_left;
- else
- n = &(*n)->rb_right;
- }
-
- return n;
-}
-
-static struct phys_desc *find_phys_mapping(void *virt)
-{
- struct rb_node **n = find_rb(virt);
-
- if(*n == NULL)
- return NULL;
-
- return rb_entry(*n, struct phys_desc, rb);
-}
-
-static void insert_phys_mapping(struct phys_desc *desc)
-{
- struct rb_node **n = find_rb(desc->virt);
-
- if(*n != NULL)
- panic("Physical remapping for %p already present",
- desc->virt);
-
- rb_link_node(&desc->rb, rb_parent(*n), n);
- rb_insert_color(&desc->rb, &phys_mappings);
-}
-
-LIST_HEAD(descriptor_mappings);
-
-struct desc_mapping {
- int fd;
- struct list_head list;
- struct list_head pages;
-};
-
-static struct desc_mapping *find_mapping(int fd)
-{
- struct desc_mapping *desc;
- struct list_head *ele;
-
- list_for_each(ele, &descriptor_mappings){
- desc = list_entry(ele, struct desc_mapping, list);
- if(desc->fd == fd)
- return desc;
- }
-
- return NULL;
-}
-
-static struct desc_mapping *descriptor_mapping(int fd)
-{
- struct desc_mapping *desc;
-
- desc = find_mapping(fd);
- if(desc != NULL)
- return desc;
-
- desc = kmalloc(sizeof(*desc), GFP_ATOMIC);
- if(desc == NULL)
- return NULL;
-
- *desc = ((struct desc_mapping)
- { .fd = fd,
- .list = LIST_HEAD_INIT(desc->list),
- .pages = LIST_HEAD_INIT(desc->pages) });
- list_add(&desc->list, &descriptor_mappings);
-
- return desc;
-}
-
-int physmem_subst_mapping(void *virt, int fd, __u64 offset, int w)
-{
- struct desc_mapping *fd_maps;
- struct phys_desc *desc;
- unsigned long phys;
- int err;
-
- fd_maps = descriptor_mapping(fd);
- if(fd_maps == NULL)
- return -ENOMEM;
-
- phys = __pa(virt);
- desc = find_phys_mapping(virt);
- if(desc != NULL)
- panic("Address 0x%p is already substituted\n", virt);
-
- err = -ENOMEM;
- desc = kmalloc(sizeof(*desc), GFP_ATOMIC);
- if(desc == NULL)
- goto out;
-
- *desc = ((struct phys_desc)
- { .fd = fd,
- .offset = offset,
- .virt = virt,
- .phys = __pa(virt),
- .list = LIST_HEAD_INIT(desc->list) });
- insert_phys_mapping(desc);
-
- list_add(&desc->list, &fd_maps->pages);
-
- virt = (void *) ((unsigned long) virt & PAGE_MASK);
- err = os_map_memory(virt, fd, offset, PAGE_SIZE, 1, w, 0);
- if(!err)
- goto out;
-
- rb_erase(&desc->rb, &phys_mappings);
- kfree(desc);
- out:
- return err;
-}
-