wash
b8ccffd2d4
vm-object can be used to demand-allocate non-contiguous physical memory, and will provide an api for userspace programs to do the same. unless a vm-object is created in-place (i.e. to represent a specific area of physical memory), its memory pages are only allocated when the object is mapped AND someone attempts to access the memory.
69 lines
1.9 KiB
C
69 lines
1.9 KiB
C
#ifndef MANGO_VM_OBJECT_H_
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#define MANGO_VM_OBJECT_H_
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#include <mango/locks.h>
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#include <mango/object.h>
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#define VM_OBJECT_NAME_MAX 64
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enum vm_object_flags {
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/* the memory behind this vm-object wasn't allocated by us, and
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* therefore shouldn't be freed by us */
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VMO_IN_PLACE = 0x01u,
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};
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struct vm_object {
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struct object vo_base;
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char vo_name[VM_OBJECT_NAME_MAX];
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enum vm_object_flags vo_flags;
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/* queue of struct vm_region_mapping */
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struct queue vo_mappings;
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/* memory protection flags. mappings of this vm_object can only use
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* a subset of the flags set in this mask. */
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enum vm_prot vo_prot;
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/* btree of vm_pages that have been allocated to this vm_object.
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* vm_page->p_vmo_offset and the size of each page is the bst key. */
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struct btree vo_pages;
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/* total length of the vm_object in bytes. */
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size_t vo_size;
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};
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extern kern_status_t vm_object_type_init(void);
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/* create a vm_object with the specified length in bytes and protection flags.
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* the length will be automatically rounded up to the nearest vm_object page
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* order size. the actual page frames themselves won't be allocated until
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* they are mapped and accessed. */
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extern struct vm_object *vm_object_create(
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const char *name,
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size_t len,
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enum vm_prot prot);
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/* create a vm_object that represents the specified range of physical memory.
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* the length will be automatically rounded up to the nearest vm_object page
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* order size.
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* NOTE this function assumes that the physical memory has already been
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* reserved, and is not in use by any other kernel component. */
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extern struct vm_object *vm_object_create_in_place(
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const char *name,
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phys_addr_t base,
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size_t len,
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enum vm_prot prot);
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extern struct vm_page *vm_object_get_page(
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const struct vm_object *vo,
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off_t offset);
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extern struct vm_page *vm_object_alloc_page(
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struct vm_object *vo,
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off_t offset,
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enum vm_page_order size);
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DEFINE_OBJECT_LOCK_FUNCTION(vm_object, vo_base)
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#endif
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