1 files changed, 29 insertions, 15 deletions

diff --git a/drivers/gpu/drm/i915/i915_mm.c b/drivers/gpu/drm/i915/i915_mm.c
index 666808cb3a32..c33bd3d83069 100644
--- a/drivers/gpu/drm/i915/i915_mm.c
+++ b/drivers/gpu/drm/i915/i915_mm.c
@@ -27,6 +27,7 @@
 
 
 #include "i915_drv.h"
+#include "i915_mm.h"
 
 struct remap_pfn {
 	struct mm_struct *mm;
@@ -37,17 +38,6 @@ 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)
@@ -77,6 +67,20 @@ static int remap_sg(pte_t *pte, unsigned long addr, void *data)
 	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
@@ -94,10 +98,9 @@ int remap_io_mapping(struct vm_area_struct *vma,
 	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(). */
+	/* We rely on prevalidation of the io-mapping to skip pfnmap tracking. */
 	r.mm = vma->vm_mm;
 	r.pfn = pfn;
 	r.prot = __pgprot((pgprot_val(iomap->prot) & _PAGE_CACHE_MASK) |
@@ -111,6 +114,7 @@ int remap_io_mapping(struct vm_area_struct *vma,
 
 	return 0;
 }
+#endif
 
 /**
  * remap_io_sg - remap an IO mapping to userspace
@@ -118,13 +122,15 @@ int remap_io_mapping(struct vm_area_struct *vma,
  * @addr: target user address to start at
  * @size: size of map area
  * @sgl: Start sg entry
+ * @offset: offset from the start of the page
  * @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 scatterlist *sgl, unsigned long offset,
+		resource_size_t iobase)
 {
 	struct remap_pfn r = {
 		.mm = vma->vm_mm,
@@ -134,9 +140,17 @@ int remap_io_sg(struct vm_area_struct *vma,
 	};
 	int err;
 
-	/* We rely on prevalidation of the io-mapping to skip track_pfn(). */
+	/* We rely on prevalidation of the io-mapping to skip pfnmap tracking. */
 	GEM_BUG_ON((vma->vm_flags & EXPECTED_FLAGS) != EXPECTED_FLAGS);
 
+	while (offset >= r.sgt.max >> PAGE_SHIFT) {
+		offset -= r.sgt.max >> PAGE_SHIFT;
+		r.sgt = __sgt_iter(__sg_next(r.sgt.sgp), use_dma(iobase));
+		if (!r.sgt.sgp)
+			return -EINVAL;
+	}
+	r.sgt.curr = offset << PAGE_SHIFT;
+
 	if (!use_dma(iobase))
 		flush_cache_range(vma, addr, size);