1 /* 2 * Copyright © 2014 Intel Corporation 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining a 5 * copy of this software and associated documentation files (the "Software"), 6 * to deal in the Software without restriction, including without limitation 7 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 8 * and/or sell copies of the Software, and to permit persons to whom the 9 * Software is furnished to do so, subject to the following conditions: 10 * 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 13 * Software. 14 * 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 18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 21 * IN THE SOFTWARE. 22 * 23 */ 24 25 #include <linux/mm.h> 26 #include <linux/io-mapping.h> 27 28 29 #include "i915_drv.h" 30 31 struct remap_pfn { 32 struct mm_struct *mm; 33 unsigned long pfn; 34 pgprot_t prot; 35 36 struct sgt_iter sgt; 37 resource_size_t iobase; 38 }; 39 40 #define use_dma(io) ((io) != -1) 41 42 static inline unsigned long sgt_pfn(const struct remap_pfn *r) 43 { 44 if (use_dma(r->iobase)) 45 return (r->sgt.dma + r->sgt.curr + r->iobase) >> PAGE_SHIFT; 46 else 47 return r->sgt.pfn + (r->sgt.curr >> PAGE_SHIFT); 48 } 49 50 static int remap_sg(pte_t *pte, unsigned long addr, void *data) 51 { 52 struct remap_pfn *r = data; 53 54 if (GEM_WARN_ON(!r->sgt.sgp)) 55 return -EINVAL; 56 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 */ 61 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)); 65 66 return 0; 67 } 68 69 #define EXPECTED_FLAGS (VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP) 70 71 /** 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 78 * 79 * Note: this is only safe if the mm semaphore is held when called. 80 */ 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) 84 { 85 struct remap_pfn r = { 86 .mm = vma->vm_mm, 87 .prot = vma->vm_page_prot, 88 .sgt = __sgt_iter(sgl, use_dma(iobase)), 89 .iobase = iobase, 90 }; 91 int err; 92 93 /* We rely on prevalidation of the io-mapping to skip track_pfn(). */ 94 GEM_BUG_ON((vma->vm_flags & EXPECTED_FLAGS) != EXPECTED_FLAGS); 95 96 if (!use_dma(iobase)) 97 flush_cache_range(vma, addr, size); 98 99 err = apply_to_page_range(r.mm, addr, size, remap_sg, &r); 100 if (unlikely(err)) { 101 zap_vma_ptes(vma, addr, r.pfn << PAGE_SHIFT); 102 return err; 103 } 104 105 return 0; 106 } 107