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);