LXR linux/mm/io-mapping.c

   1// SPDX-License-Identifier: GPL-2.0-only
   2
   3#include <linux/mm.h>
   4#include <linux/io-mapping.h>
   5
   6/**
   7 * io_mapping_map_user - remap an I/O mapping to userspace
   8 * @iomap: the source io_mapping
   9 * @vma: user vma to map to
  10 * @addr: target user address to start at
  11 * @pfn: physical address of kernel memory
  12 * @size: size of map area
  13 *
  14 *  Note: this is only safe if the mm semaphore is held when called.
  15 */
  16int io_mapping_map_user(struct io_mapping *iomap, struct vm_area_struct *vma,
  17                unsigned long addr, unsigned long pfn, unsigned long size)
  18{
  19        vm_flags_t expected_flags = VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
  20
  21        if (WARN_ON_ONCE((vma->vm_flags & expected_flags) != expected_flags))
  22                return -EINVAL;
  23
  24        /* We rely on prevalidation of the io-mapping to skip track_pfn(). */
  25        return remap_pfn_range_notrack(vma, addr, pfn, size,
  26                __pgprot((pgprot_val(iomap->prot) & _PAGE_CACHE_MASK) |
  27                         (pgprot_val(vma->vm_page_prot) & ~_PAGE_CACHE_MASK)));
  28}
  29EXPORT_SYMBOL_GPL(io_mapping_map_user);
  30