155 lines
4.3 KiB
C
155 lines
4.3 KiB
C
/*
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* Copyright © 2014 Intel Corporation
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*
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*/
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#include <linux/mm.h>
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#include <linux/io-mapping.h>
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#include "i915_drv.h"
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#include "i915_mm.h"
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struct remap_pfn {
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struct mm_struct *mm;
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unsigned long pfn;
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pgprot_t prot;
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struct sgt_iter sgt;
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resource_size_t iobase;
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};
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#define use_dma(io) ((io) != -1)
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static inline unsigned long sgt_pfn(const struct remap_pfn *r)
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{
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if (use_dma(r->iobase))
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return (r->sgt.dma + r->sgt.curr + r->iobase) >> PAGE_SHIFT;
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else
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return r->sgt.pfn + (r->sgt.curr >> PAGE_SHIFT);
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}
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static int remap_sg(pte_t *pte, unsigned long addr, void *data)
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{
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struct remap_pfn *r = data;
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if (GEM_WARN_ON(!r->sgt.sgp))
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return -EINVAL;
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/* Special PTE are not associated with any struct page */
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set_pte_at(r->mm, addr, pte,
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pte_mkspecial(pfn_pte(sgt_pfn(r), r->prot)));
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r->pfn++; /* track insertions in case we need to unwind later */
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r->sgt.curr += PAGE_SIZE;
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if (r->sgt.curr >= r->sgt.max)
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r->sgt = __sgt_iter(__sg_next(r->sgt.sgp), use_dma(r->iobase));
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return 0;
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}
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#define EXPECTED_FLAGS (VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP)
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#if IS_ENABLED(CONFIG_X86)
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static int remap_pfn(pte_t *pte, unsigned long addr, void *data)
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{
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struct remap_pfn *r = data;
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/* Special PTE are not associated with any struct page */
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set_pte_at(r->mm, addr, pte, pte_mkspecial(pfn_pte(r->pfn, r->prot)));
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r->pfn++;
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return 0;
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}
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/**
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* remap_io_mapping - remap an IO mapping to userspace
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* @vma: user vma to map to
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* @addr: target user address to start at
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* @pfn: physical address of kernel memory
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* @size: size of map area
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* @iomap: the source io_mapping
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*
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* Note: this is only safe if the mm semaphore is held when called.
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*/
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int remap_io_mapping(struct vm_area_struct *vma,
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unsigned long addr, unsigned long pfn, unsigned long size,
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struct io_mapping *iomap)
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{
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struct remap_pfn r;
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int err;
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GEM_BUG_ON((vma->vm_flags & EXPECTED_FLAGS) != EXPECTED_FLAGS);
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/* We rely on prevalidation of the io-mapping to skip track_pfn(). */
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r.mm = vma->vm_mm;
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r.pfn = pfn;
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r.prot = __pgprot((pgprot_val(iomap->prot) & _PAGE_CACHE_MASK) |
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(pgprot_val(vma->vm_page_prot) & ~_PAGE_CACHE_MASK));
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err = apply_to_page_range(r.mm, addr, size, remap_pfn, &r);
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if (unlikely(err)) {
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zap_vma_ptes(vma, addr, (r.pfn - pfn) << PAGE_SHIFT);
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return err;
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}
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return 0;
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}
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#endif
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/**
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* remap_io_sg - remap an IO mapping to userspace
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* @vma: user vma to map to
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* @addr: target user address to start at
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* @size: size of map area
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* @sgl: Start sg entry
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* @iobase: Use stored dma address offset by this address or pfn if -1
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*
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* Note: this is only safe if the mm semaphore is held when called.
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*/
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int remap_io_sg(struct vm_area_struct *vma,
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unsigned long addr, unsigned long size,
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struct scatterlist *sgl, resource_size_t iobase)
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{
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struct remap_pfn r = {
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.mm = vma->vm_mm,
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.prot = vma->vm_page_prot,
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.sgt = __sgt_iter(sgl, use_dma(iobase)),
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.iobase = iobase,
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};
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int err;
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/* We rely on prevalidation of the io-mapping to skip track_pfn(). */
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GEM_BUG_ON((vma->vm_flags & EXPECTED_FLAGS) != EXPECTED_FLAGS);
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if (!use_dma(iobase))
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flush_cache_range(vma, addr, size);
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err = apply_to_page_range(r.mm, addr, size, remap_sg, &r);
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if (unlikely(err)) {
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zap_vma_ptes(vma, addr, r.pfn << PAGE_SHIFT);
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return err;
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}
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return 0;
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}
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