io-mapping.c 993 B

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. #include <linux/mm.h>
  3. #include <linux/io-mapping.h>
  4. /**
  5. * io_mapping_map_user - remap an I/O mapping to userspace
  6. * @iomap: the source io_mapping
  7. * @vma: user vma to map to
  8. * @addr: target user address to start at
  9. * @pfn: physical address of kernel memory
  10. * @size: size of map area
  11. *
  12. * Note: this is only safe if the mm semaphore is held when called.
  13. */
  14. int io_mapping_map_user(struct io_mapping *iomap, struct vm_area_struct *vma,
  15. unsigned long addr, unsigned long pfn, unsigned long size)
  16. {
  17. vm_flags_t expected_flags = VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
  18. if (WARN_ON_ONCE((vma->vm_flags & expected_flags) != expected_flags))
  19. return -EINVAL;
  20. /* We rely on prevalidation of the io-mapping to skip track_pfn(). */
  21. return remap_pfn_range_notrack(vma, addr, pfn, size,
  22. __pgprot((pgprot_val(iomap->prot) & _PAGE_CACHE_MASK) |
  23. (pgprot_val(vma->vm_page_prot) & ~_PAGE_CACHE_MASK)));
  24. }
  25. EXPORT_SYMBOL_GPL(io_mapping_map_user);