2 * Copyright © 2014 Intel Corporation
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5 * copy of this software and associated documentation files (the "Software"),
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9 * Software is furnished to do so, subject to the following conditions:
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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26 #include <linux/io-mapping.h>
37 resource_size_t iobase;
40 #define use_dma(io) ((io) != -1)
42 static inline unsigned long sgt_pfn(const struct remap_pfn *r)
44 if (use_dma(r->iobase))
45 return (r->sgt.dma + r->sgt.curr + r->iobase) >> PAGE_SHIFT;
47 return r->sgt.pfn + (r->sgt.curr >> PAGE_SHIFT);
50 static int remap_sg(pte_t *pte, unsigned long addr, void *data)
52 struct remap_pfn *r = data;
54 if (GEM_WARN_ON(!r->sgt.sgp))
57 /* Special PTE are not associated with any struct page */
58 set_pte_at(r->mm, addr, pte,
59 pte_mkspecial(pfn_pte(sgt_pfn(r), r->prot)));
60 r->pfn++; /* track insertions in case we need to unwind later */
62 r->sgt.curr += PAGE_SIZE;
63 if (r->sgt.curr >= r->sgt.max)
64 r->sgt = __sgt_iter(__sg_next(r->sgt.sgp), use_dma(r->iobase));
69 #define EXPECTED_FLAGS (VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP)
72 * remap_io_sg - remap an IO mapping to userspace
73 * @vma: user vma to map to
74 * @addr: target user address to start at
75 * @size: size of map area
76 * @sgl: Start sg entry
77 * @iobase: Use stored dma address offset by this address or pfn if -1
79 * Note: this is only safe if the mm semaphore is held when called.
81 int remap_io_sg(struct vm_area_struct *vma,
82 unsigned long addr, unsigned long size,
83 struct scatterlist *sgl, resource_size_t iobase)
85 struct remap_pfn r = {
87 .prot = vma->vm_page_prot,
88 .sgt = __sgt_iter(sgl, use_dma(iobase)),
93 /* We rely on prevalidation of the io-mapping to skip track_pfn(). */
94 GEM_BUG_ON((vma->vm_flags & EXPECTED_FLAGS) != EXPECTED_FLAGS);
97 flush_cache_range(vma, addr, size);
99 err = apply_to_page_range(r.mm, addr, size, remap_sg, &r);
101 zap_vma_ptes(vma, addr, r.pfn << PAGE_SHIFT);