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 32struct 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 43static 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#ifdef notyet 52 53static int remap_sg(pte_t *pte, unsigned long addr, void *data) 54{ 55 struct remap_pfn *r = data; 56 57 if (GEM_WARN_ON(!r->sgt.sgp)) 58 return -EINVAL; 59 60 /* Special PTE are not associated with any struct vm_page */ 61 set_pte_at(r->mm, addr, pte, 62 pte_mkspecial(pfn_pte(sgt_pfn(r), r->prot))); 63 r->pfn++; /* track insertions in case we need to unwind later */ 64 65 r->sgt.curr += PAGE_SIZE; 66 if (r->sgt.curr >= r->sgt.max) 67 r->sgt = __sgt_iter(__sg_next(r->sgt.sgp), use_dma(r->iobase)); 68 69 return 0; 70} 71 72#define EXPECTED_FLAGS (VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP) 73 74#if IS_ENABLED(CONFIG_X86) 75#ifdef notyet 76static int remap_pfn(pte_t *pte, unsigned long addr, void *data) 77{ 78 struct remap_pfn *r = data; 79 80 /* Special PTE are not associated with any struct page */ 81 set_pte_at(r->mm, addr, pte, pte_mkspecial(pfn_pte(r->pfn, r->prot))); 82 r->pfn++; 83 84 return 0; 85} 86#endif 87 88/** 89 * remap_io_mapping - remap an IO mapping to userspace 90 * @vma: user vma to map to 91 * @addr: target user address to start at 92 * @pfn: physical address of kernel memory 93 * @size: size of map area 94 * @iomap: the source io_mapping 95 * 96 * Note: this is only safe if the mm semaphore is held when called. 97 */ 98int remap_io_mapping(struct vm_area_struct *vma, 99 unsigned long addr, unsigned long pfn, unsigned long size, 100 struct io_mapping *iomap) 101{ 102 struct remap_pfn r; 103 int err; 104 105 GEM_BUG_ON((vma->vm_flags & EXPECTED_FLAGS) != EXPECTED_FLAGS); 106 107 /* We rely on prevalidation of the io-mapping to skip track_pfn(). */ 108 r.mm = vma->vm_mm; 109 r.pfn = pfn; 110 r.prot = __pgprot((pgprot_val(iomap->prot) & _PAGE_CACHE_MASK) | 111 (pgprot_val(vma->vm_page_prot) & ~_PAGE_CACHE_MASK)); 112 113 err = apply_to_page_range(r.mm, addr, size, remap_pfn, &r); 114 if (unlikely(err)) { 115 zap_vma_ptes(vma, addr, (r.pfn - pfn) << PAGE_SHIFT); 116 return err; 117 } 118 119 return 0; 120} 121#endif 122 123/** 124 * remap_io_sg - remap an IO mapping to userspace 125 * @vma: user vma to map to 126 * @addr: target user address to start at 127 * @size: size of map area 128 * @sgl: Start sg entry 129 * @iobase: Use stored dma address offset by this address or pfn if -1 130 * 131 * Note: this is only safe if the mm semaphore is held when called. 132 */ 133int remap_io_sg(struct vm_area_struct *vma, 134 unsigned long addr, unsigned long size, 135 struct scatterlist *sgl, resource_size_t iobase) 136{ 137 struct remap_pfn r = { 138 .mm = vma->vm_mm, 139 .prot = vma->vm_page_prot, 140 .sgt = __sgt_iter(sgl, use_dma(iobase)), 141 .iobase = iobase, 142 }; 143 int err; 144 145 /* We rely on prevalidation of the io-mapping to skip track_pfn(). */ 146 GEM_BUG_ON((vma->vm_flags & EXPECTED_FLAGS) != EXPECTED_FLAGS); 147 148 if (!use_dma(iobase)) 149 flush_cache_range(vma, addr, size); 150 151 err = apply_to_page_range(r.mm, addr, size, remap_sg, &r); 152 if (unlikely(err)) { 153 zap_vma_ptes(vma, addr, r.pfn << PAGE_SHIFT); 154 return err; 155 } 156 157 return 0; 158} 159 160#endif /* notyet */ 161