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53 lines
1.3 KiB
C
53 lines
1.3 KiB
C
/*
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* Copyright (C) 2008 Bahadir Balban
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*/
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#include <l4/lib/list.h>
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#include <vm_area.h>
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#include <kmalloc/kmalloc.h>
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/*
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* This is yet unused, it is more of an anticipation
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* of how mmaped devices would be mapped with a pager.
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*/
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struct mmap_device {
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struct list_head page_list; /* Dyn-allocated page list */
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unsigned long pfn_start; /* Physical pfn start */
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unsigned long pfn_end; /* Physical pfn end */
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};
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struct page *memdev_page_in(struct vm_object *vm_obj,
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unsigned long pfn_offset)
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{
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struct vm_file *f = vm_object_to_file(vm_obj);
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struct mmap_device *memdev = f->priv_data;
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struct page *page;
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/* Check if its within device boundary */
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if (pfn_offset >= memdev->pfn_end - memdev->pfn_start)
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return PTR_ERR(-1);
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/* Simply return the page if found */
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list_for_each_entry(page, &memdev->page_list, list)
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if (page->offset == pfn_offset)
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return page;
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/* Otherwise allocate one of our own for that offset and return it */
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page = kzalloc(sizeof(struct page));
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INIT_LIST_HEAD(&page->list);
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spin_lock_init(&page->lock);
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page->offset = pfn_offset;
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page->owner = vm_obj;
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list_add(&page->list, &memdev->page_list);
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return page;
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}
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/* All mmapable devices are handled by this */
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struct vm_pager memdev_pager = {
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.ops = {
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.page_in = memdev_page_in,
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},
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};
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