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