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 #include "i915_mm.h" 31 32 struct remap_pfn { 33 struct mm_struct *mm; 34 unsigned long pfn; 35 pgprot_t prot; 36 37 struct sgt_iter sgt; 38 resource_size_t iobase; 39 }; 40 41 #define use_dma(io) ((io) != -1) 42 43 static inline unsigned long sgt_pfn(const struct remap_pfn *r) 44 { 45 if (use_dma(r->iobase)) 46 return (r->sgt.dma + r->sgt.curr + r->iobase) >> PAGE_SHIFT; 47 else 48 return r->sgt.pfn + (r->sgt.curr >> PAGE_SHIFT); 49 } 50 51 static int remap_sg(pte_t *pte, unsigned long addr, void *data) 52 { 53 struct remap_pfn *r = data; 54 55 if (GEM_WARN_ON(!r->sgt.sgp)) 56 return -EINVAL; 57 58 /* Special PTE are not associated with any struct page */ 59 set_pte_at(r->mm, addr, pte, 60 pte_mkspecial(pfn_pte(sgt_pfn(r), r->prot))); 61 r->pfn++; /* track insertions in case we need to unwind later */ 62 63 r->sgt.curr += PAGE_SIZE; 64 if (r->sgt.curr >= r->sgt.max) 65 r->sgt = __sgt_iter(__sg_next(r->sgt.sgp), use_dma(r->iobase)); 66 67 return 0; 68 } 69 70 #define EXPECTED_FLAGS (VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP) 71 72 #if IS_ENABLED(CONFIG_X86) 73 static int remap_pfn(pte_t *pte, unsigned long addr, void *data) 74 { 75 struct remap_pfn *r = data; 76 77 /* Special PTE are not associated with any struct page */ 78 set_pte_at(r->mm, addr, pte, pte_mkspecial(pfn_pte(r->pfn, r->prot))); 79 r->pfn++; 80 81 return 0; 82 } 83 84 /** 85 * remap_io_mapping - remap an IO mapping to userspace 86 * @vma: user vma to map to 87 * @addr: target user address to start at 88 * @pfn: physical address of kernel memory 89 * @size: size of map area 90 * @iomap: the source io_mapping 91 * 92 * Note: this is only safe if the mm semaphore is held when called. 93 */ 94 int remap_io_mapping(struct vm_area_struct *vma, 95 unsigned long addr, unsigned long pfn, unsigned long size, 96 struct io_mapping *iomap) 97 { 98 struct remap_pfn r; 99 int err; 100 101 GEM_BUG_ON((vma->vm_flags & EXPECTED_FLAGS) != EXPECTED_FLAGS); 102 103 /* We rely on prevalidation of the io-mapping to skip track_pfn(). */ 104 r.mm = vma->vm_mm; 105 r.pfn = pfn; 106 r.prot = __pgprot((pgprot_val(iomap->prot) & _PAGE_CACHE_MASK) | 107 (pgprot_val(vma->vm_page_prot) & ~_PAGE_CACHE_MASK)); 108 109 err = apply_to_page_range(r.mm, addr, size, remap_pfn, &r); 110 if (unlikely(err)) { 111 zap_vma_ptes(vma, addr, (r.pfn - pfn) << PAGE_SHIFT); 112 return err; 113 } 114 115 return 0; 116 } 117 #endif 118 119 /** 120 * remap_io_sg - remap an IO mapping to userspace 121 * @vma: user vma to map to 122 * @addr: target user address to start at 123 * @size: size of map area 124 * @sgl: Start sg entry 125 * @iobase: Use stored dma address offset by this address or pfn if -1 126 * 127 * Note: this is only safe if the mm semaphore is held when called. 128 */ 129 int remap_io_sg(struct vm_area_struct *vma, 130 unsigned long addr, unsigned long size, 131 struct scatterlist *sgl, resource_size_t iobase) 132 { 133 struct remap_pfn r = { 134 .mm = vma->vm_mm, 135 .prot = vma->vm_page_prot, 136 .sgt = __sgt_iter(sgl, use_dma(iobase)), 137 .iobase = iobase, 138 }; 139 int err; 140 141 /* We rely on prevalidation of the io-mapping to skip track_pfn(). */ 142 GEM_BUG_ON((vma->vm_flags & EXPECTED_FLAGS) != EXPECTED_FLAGS); 143 144 if (!use_dma(iobase)) 145 flush_cache_range(vma, addr, size); 146 147 err = apply_to_page_range(r.mm, addr, size, remap_sg, &r); 148 if (unlikely(err)) { 149 zap_vma_ptes(vma, addr, r.pfn << PAGE_SHIFT); 150 return err; 151 } 152 153 return 0; 154 } 155