diff options
Diffstat (limited to 'drivers/gpu/drm/i915/i915_mm.c')
| -rw-r--r-- | drivers/gpu/drm/i915/i915_mm.c | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_mm.c b/drivers/gpu/drm/i915/i915_mm.c index 9a777b0ff59b..666808cb3a32 100644 --- a/drivers/gpu/drm/i915/i915_mm.c +++ b/drivers/gpu/drm/i915/i915_mm.c @@ -37,6 +37,17 @@ struct remap_pfn { resource_size_t iobase; }; +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; +} + #define use_dma(io) ((io) != -1) static inline unsigned long sgt_pfn(const struct remap_pfn *r) @@ -66,7 +77,40 @@ static int remap_sg(pte_t *pte, unsigned long addr, void *data) 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; + #define EXPECTED_FLAGS (VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP) + 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; +} /** * remap_io_sg - remap an IO mapping to userspace |