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 #include <asm/pgtable.h> 29 30 #include "i915_drv.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 static int remap_pfn(pte_t *pte, unsigned long addr, void *data) 42 { 43 struct remap_pfn *r = data; 44 45 /* Special PTE are not associated with any struct page */ 46 set_pte_at(r->mm, addr, pte, pte_mkspecial(pfn_pte(r->pfn, r->prot))); 47 r->pfn++; 48 49 return 0; 50 } 51 52 #define use_dma(io) ((io) != -1) 53 54 static inline unsigned long sgt_pfn(const struct remap_pfn *r) 55 { 56 if (use_dma(r->iobase)) 57 return (r->sgt.dma + r->sgt.curr + r->iobase) >> PAGE_SHIFT; 58 else 59 return r->sgt.pfn + (r->sgt.curr >> PAGE_SHIFT); 60 } 61 62 static int remap_sg(pte_t *pte, unsigned long addr, void *data) 63 { 64 struct remap_pfn *r = data; 65 66 if (GEM_WARN_ON(!r->sgt.pfn)) 67 return -EINVAL; 68 69 /* Special PTE are not associated with any struct page */ 70 set_pte_at(r->mm, addr, pte, 71 pte_mkspecial(pfn_pte(sgt_pfn(r), r->prot))); 72 r->pfn++; /* track insertions in case we need to unwind later */ 73 74 r->sgt.curr += PAGE_SIZE; 75 if (r->sgt.curr >= r->sgt.max) 76 r->sgt = __sgt_iter(__sg_next(r->sgt.sgp), use_dma(r->iobase)); 77 78 return 0; 79 } 80 81 /** 82 * remap_io_mapping - remap an IO mapping to userspace 83 * @vma: user vma to map to 84 * @addr: target user address to start at 85 * @pfn: physical address of kernel memory 86 * @size: size of map area 87 * @iomap: the source io_mapping 88 * 89 * Note: this is only safe if the mm semaphore is held when called. 90 */ 91 int remap_io_mapping(struct vm_area_struct *vma, 92 unsigned long addr, unsigned long pfn, unsigned long size, 93 struct io_mapping *iomap) 94 { 95 struct remap_pfn r; 96 int err; 97 98 #define EXPECTED_FLAGS (VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP) 99 GEM_BUG_ON((vma->vm_flags & EXPECTED_FLAGS) != EXPECTED_FLAGS); 100 101 /* We rely on prevalidation of the io-mapping to skip track_pfn(). */ 102 r.mm = vma->vm_mm; 103 r.pfn = pfn; 104 r.prot = __pgprot((pgprot_val(iomap->prot) & _PAGE_CACHE_MASK) | 105 (pgprot_val(vma->vm_page_prot) & ~_PAGE_CACHE_MASK)); 106 107 err = apply_to_page_range(r.mm, addr, size, remap_pfn, &r); 108 if (unlikely(err)) { 109 zap_vma_ptes(vma, addr, (r.pfn - pfn) << PAGE_SHIFT); 110 return err; 111 } 112 113 return 0; 114 } 115 116 /** 117 * remap_io_sg - remap an IO mapping to userspace 118 * @vma: user vma to map to 119 * @addr: target user address to start at 120 * @size: size of map area 121 * @sgl: Start sg entry 122 * @iobase: Use stored dma address offset by this address or pfn if -1 123 * 124 * Note: this is only safe if the mm semaphore is held when called. 125 */ 126 int remap_io_sg(struct vm_area_struct *vma, 127 unsigned long addr, unsigned long size, 128 struct scatterlist *sgl, resource_size_t iobase) 129 { 130 struct remap_pfn r = { 131 .mm = vma->vm_mm, 132 .prot = vma->vm_page_prot, 133 .sgt = __sgt_iter(sgl, use_dma(iobase)), 134 .iobase = iobase, 135 }; 136 int err; 137 138 /* We rely on prevalidation of the io-mapping to skip track_pfn(). */ 139 GEM_BUG_ON((vma->vm_flags & EXPECTED_FLAGS) != EXPECTED_FLAGS); 140 141 if (!use_dma(iobase)) 142 flush_cache_range(vma, addr, size); 143 144 err = apply_to_page_range(r.mm, addr, size, remap_sg, &r); 145 if (unlikely(err)) { 146 zap_vma_ptes(vma, addr, r.pfn << PAGE_SHIFT); 147 return err; 148 } 149 150 return 0; 151 } 152