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 38 static int remap_pfn(pte_t *pte, unsigned long addr, void *data) 39 { 40 struct remap_pfn *r = data; 41 42 /* Special PTE are not associated with any struct page */ 43 set_pte_at(r->mm, addr, pte, pte_mkspecial(pfn_pte(r->pfn, r->prot))); 44 r->pfn++; 45 46 return 0; 47 } 48 49 /** 50 * remap_io_mapping - remap an IO mapping to userspace 51 * @vma: user vma to map to 52 * @addr: target user address to start at 53 * @pfn: physical address of kernel memory 54 * @size: size of map area 55 * @iomap: the source io_mapping 56 * 57 * Note: this is only safe if the mm semaphore is held when called. 58 */ 59 int remap_io_mapping(struct vm_area_struct *vma, 60 unsigned long addr, unsigned long pfn, unsigned long size, 61 struct io_mapping *iomap) 62 { 63 struct remap_pfn r; 64 int err; 65 66 GEM_BUG_ON((vma->vm_flags & 67 (VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP)) != 68 (VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP)); 69 70 /* We rely on prevalidation of the io-mapping to skip track_pfn(). */ 71 r.mm = vma->vm_mm; 72 r.pfn = pfn; 73 r.prot = __pgprot((pgprot_val(iomap->prot) & _PAGE_CACHE_MASK) | 74 (pgprot_val(vma->vm_page_prot) & ~_PAGE_CACHE_MASK)); 75 76 err = apply_to_page_range(r.mm, addr, size, remap_pfn, &r); 77 if (unlikely(err)) { 78 zap_vma_ptes(vma, addr, (r.pfn - pfn) << PAGE_SHIFT); 79 return err; 80 } 81 82 return 0; 83 } 84