diff options
Diffstat (limited to 'drivers/gpu/drm/i915/i915_mm.c')
| -rw-r--r-- | drivers/gpu/drm/i915/i915_mm.c | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_mm.c b/drivers/gpu/drm/i915/i915_mm.c new file mode 100644 index 000000000..7998bc74a --- /dev/null +++ b/drivers/gpu/drm/i915/i915_mm.c @@ -0,0 +1,154 @@ +/* + * 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; +} |