drm/ttm: Fix ttm in-kernel copying of pages with non-standard caching attributes.

For x86 this affected highmem pages only, since they were always kmapped
cache-coherent, and this is fixed using kmap_atomic_prot().

For other architectures that may not modify the linear kernel map we
resort to vmap() for now, since kmap_atomic_prot() generally uses the
linear kernel map for lowmem pages. This of course comes with a
performance impact and should be optimized when possible.

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

1 files changed, 52 insertions, 11 deletions

diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
index 3e5d0c4ad85c..ce2e6f38ea01 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_util.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
@@ -136,7 +136,8 @@ static int ttm_copy_io_page(void *dst, void *src, unsigned long page)
 }
 
 static int ttm_copy_io_ttm_page(struct ttm_tt *ttm, void *src,
-                                unsigned long page)
+                                unsigned long page,
+                                pgprot_t prot)
 {
         struct page *d = ttm_tt_get_page(ttm, page);
         void *dst;
@@ -145,17 +146,35 @@ static int ttm_copy_io_ttm_page(struct ttm_tt *ttm, void *src,
                 return -ENOMEM;
 
         src = (void *)((unsigned long)src + (page << PAGE_SHIFT));
-        dst = kmap(d);
+
+#ifdef CONFIG_X86
+        dst = kmap_atomic_prot(d, KM_USER0, prot);
+#else
+        if (prot != PAGE_KERNEL)
+                dst = vmap(&d, 1, 0, prot);
+        else
+                dst = kmap(d);
+#endif
         if (!dst)
                 return -ENOMEM;
 
         memcpy_fromio(dst, src, PAGE_SIZE);
-        kunmap(d);
+
+#ifdef CONFIG_X86
+        kunmap_atomic(dst, KM_USER0);
+#else
+        if (prot != PAGE_KERNEL)
+                vunmap(dst);
+        else
+                kunmap(d);
+#endif
+
         return 0;
 }
 
 static int ttm_copy_ttm_io_page(struct ttm_tt *ttm, void *dst,
-                                unsigned long page)
+                                unsigned long page,
+                                pgprot_t prot)
 {
         struct page *s = ttm_tt_get_page(ttm, page);
         void *src;
@@ -164,12 +183,28 @@ static int ttm_copy_ttm_io_page(struct ttm_tt *ttm, void *dst,
                 return -ENOMEM;
 
         dst = (void *)((unsigned long)dst + (page << PAGE_SHIFT));
-        src = kmap(s);
+#ifdef CONFIG_X86
+        src = kmap_atomic_prot(s, KM_USER0, prot);
+#else
+        if (prot != PAGE_KERNEL)
+                src = vmap(&s, 1, 0, prot);
+        else
+                src = kmap(s);
+#endif
         if (!src)
                 return -ENOMEM;
 
         memcpy_toio(dst, src, PAGE_SIZE);
-        kunmap(s);
+
+#ifdef CONFIG_X86
+        kunmap_atomic(src, KM_USER0);
+#else
+        if (prot != PAGE_KERNEL)
+                vunmap(src);
+        else
+                kunmap(s);
+#endif
+
         return 0;
 }
 
@@ -214,11 +249,17 @@ int ttm_bo_move_memcpy(struct ttm_buffer_object *bo,
 
         for (i = 0; i < new_mem->num_pages; ++i) {
                 page = i * dir + add;
-                if (old_iomap == NULL)
-                        ret = ttm_copy_ttm_io_page(ttm, new_iomap, page);
-                else if (new_iomap == NULL)
-                        ret = ttm_copy_io_ttm_page(ttm, old_iomap, page);
-                else
+                if (old_iomap == NULL) {
+                        pgprot_t prot = ttm_io_prot(old_mem->placement,
+                                                    PAGE_KERNEL);
+                        ret = ttm_copy_ttm_io_page(ttm, new_iomap, page,
+                                                   prot);
+                } else if (new_iomap == NULL) {
+                        pgprot_t prot = ttm_io_prot(new_mem->placement,
+                                                    PAGE_KERNEL);
+                        ret = ttm_copy_io_ttm_page(ttm, old_iomap, page,
+                                                   prot);
+                } else
                         ret = ttm_copy_io_page(new_iomap, old_iomap, page);
                 if (ret)
                         goto out1;