drm/ttm: powerpc: Fix Highmem cache flushing.

Temporarily maps highmem pages while flushing to get a valid virtual
address to flush.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 10 insertions, 4 deletions

diff --git a/drivers/gpu/drm/ttm/ttm_tt.c b/drivers/gpu/drm/ttm/ttm_tt.c
index 81ab81f030a3..9b2248a80cff 100644
--- a/drivers/gpu/drm/ttm/ttm_tt.c
+++ b/drivers/gpu/drm/ttm/ttm_tt.c
@@ -86,10 +86,16 @@ void ttm_tt_cache_flush(struct page *pages[], unsigned long num_pages)
         unsigned long i;
 
         for (i = 0; i < num_pages; ++i) {
-                if (pages[i]) {
-                        unsigned long start = (unsigned long)page_address(pages[i]);
-                        flush_dcache_range(start, start + PAGE_SIZE);
-                }
+                struct page *page = pages[i];
+                void *page_virtual;
+
+                if (unlikely(page == NULL))
+                        continue;
+
+                page_virtual = kmap_atomic(page, KM_USER0);
+                flush_dcache_range((unsigned long) page_virtual,
+                                   (unsigned long) page_virtual + PAGE_SIZE);
+                kunmap_atomic(page_virtual, KM_USER0);
         }
 #else
         if (on_each_cpu(ttm_tt_ipi_handler, NULL, 1) != 0)