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 static int remap_pfn(pte_t *pte, unsigned long addr, void *data) 41 { 42 struct remap_pfn *r = data; 43 44 /* Special PTE are not associated with any struct page */ 45 set_pte_at(r->mm, addr, pte, pte_mkspecial(pfn_pte(r->pfn, r->prot))); 46 r->pfn++; 47 48 return 0; 49 } 50 51 #define use_dma(io) ((io) != -1) 52 53 static inline unsigned long sgt_pfn(const struct remap_pfn *r) 54 { 55 if (use_dma(r->iobase)) 56 return (r->sgt.dma + r->sgt.curr + r->iobase) >> PAGE_SHIFT; 57 else 58 return r->sgt.pfn + (r->sgt.curr >> PAGE_SHIFT); 59 } 60 61 static int remap_sg(pte_t *pte, unsigned long addr, void *data) 62 { 63 struct remap_pfn *r = data; 64 65 if (GEM_WARN_ON(!r->sgt.sgp)) 66 return -EINVAL; 67 68 /* Special PTE are not associated with any struct page */ 69 set_pte_at(r->mm, addr, pte, 70 pte_mkspecial(pfn_pte(sgt_pfn(r), r->prot))); 71 r->pfn++; /* track insertions in case we need to unwind later */ 72 73 r->sgt.curr += PAGE_SIZE; 74 if (r->sgt.curr >= r->sgt.max) 75 r->sgt = __sgt_iter(__sg_next(r->sgt.sgp), use_dma(r->iobase)); 76 77 return 0; 78 } 79 80 /** 81 * remap_io_mapping - remap an IO mapping to userspace 82 * @vma: user vma to map to 83 * @addr: target user address to start at 84 * @pfn: physical address of kernel memory 85 * @size: size of map area 86 * @iomap: the source io_mapping 87 * 88 * Note: this is only safe if the mm semaphore is held when called. 89 */ 90 int remap_io_mapping(struct vm_area_struct *vma, 91 unsigned long addr, unsigned long pfn, unsigned long size, 92 struct io_mapping *iomap) 93 { 94 struct remap_pfn r; 95 int err; 96 97 #define EXPECTED_FLAGS (VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP) 98 GEM_BUG_ON((vma->vm_flags & EXPECTED_FLAGS) != EXPECTED_FLAGS); 99 100 /* We rely on prevalidation of the io-mapping to skip track_pfn(). */ 101 r.mm = vma->vm_mm; 102 r.pfn = pfn; 103 r.prot = __pgprot((pgprot_val(iomap->prot) & _PAGE_CACHE_MASK) | 104 (pgprot_val(vma->vm_page_prot) & ~_PAGE_CACHE_MASK)); 105 106 err = apply_to_page_range(r.mm, addr, size, remap_pfn, &r); 107 if (unlikely(err)) { 108 zap_vma_ptes(vma, addr, (r.pfn - pfn) << PAGE_SHIFT); 109 return err; 110 } 111 112 return 0; 113 } 114 115 /** 116 * remap_io_sg - remap an IO mapping to userspace 117 * @vma: user vma to map to 118 * @addr: target user address to start at 119 * @size: size of map area 120 * @sgl: Start sg entry 121 * @iobase: Use stored dma address offset by this address or pfn if -1 122 * 123 * Note: this is only safe if the mm semaphore is held when called. 124 */ 125 int remap_io_sg(struct vm_area_struct *vma, 126 unsigned long addr, unsigned long size, 127 struct scatterlist *sgl, resource_size_t iobase) 128 { 129 struct remap_pfn r = { 130 .mm = vma->vm_mm, 131 .prot = vma->vm_page_prot, 132 .sgt = __sgt_iter(sgl, use_dma(iobase)), 133 .iobase = iobase, 134 }; 135 int err; 136 137 /* We rely on prevalidation of the io-mapping to skip track_pfn(). */ 138 GEM_BUG_ON((vma->vm_flags & EXPECTED_FLAGS) != EXPECTED_FLAGS); 139 140 if (!use_dma(iobase)) 141 flush_cache_range(vma, addr, size); 142 143 err = apply_to_page_range(r.mm, addr, size, remap_sg, &r); 144 if (unlikely(err)) { 145 zap_vma_ptes(vma, addr, r.pfn << PAGE_SHIFT); 146 return err; 147 } 148 149 return 0; 150 } 151