drm/vmwgfx: Allow resource relocations on byte boundaries

So far, resource allocations have only been allowed on 4-byte boundaries.
As commands get packed tighter, allow them on byte boundaries.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Sinclair Yeh <syeh@vmware.com>
Signed-off-by: Sinclair Yeh <syeh@vmware.com>

1 files changed, 26 insertions, 15 deletions

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
index 0243acc8845f..b915f621187f 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
@@ -39,7 +39,7 @@
  *
  * @head: List head for the software context's relocation list.
  * @res: Non-ref-counted pointer to the resource.
- * @offset: Offset of 4 byte entries into the command buffer where the
+ * @offset: Offset of single byte entries into the command buffer where the
  * id that needs fixup is located.
  */
 struct vmw_resource_relocation {
@@ -109,7 +109,18 @@ static int vmw_bo_to_validate_list(struct vmw_sw_context *sw_context,
                                    struct vmw_dma_buffer *vbo,
                                    bool validate_as_mob,
                                    uint32_t *p_val_node);
-
+/**
+ * vmw_ptr_diff - Compute the offset from a to b in bytes
+ *
+ * @a: A starting pointer.
+ * @b: A pointer offset in the same address space.
+ *
+ * Returns: The offset in bytes between the two pointers.
+ */
+static size_t vmw_ptr_diff(void *a, void *b)
+{
+        return (unsigned long) b - (unsigned long) a;
+}
 
 /**
  * vmw_resources_unreserve - unreserve resources previously reserved for
@@ -409,7 +420,7 @@ static int vmw_resource_context_res_add(struct vmw_private *dev_priv,
  * @list: Pointer to head of relocation list.
  * @res: The resource.
  * @offset: Offset into the command buffer currently being parsed where the
- * id that needs fixup is located. Granularity is 4 bytes.
+ * id that needs fixup is located. Granularity is one byte.
  */
 static int vmw_resource_relocation_add(struct list_head *list,
                                        const struct vmw_resource *res,
@@ -460,10 +471,11 @@ static void vmw_resource_relocations_apply(uint32_t *cb,
         struct vmw_resource_relocation *rel;
 
         list_for_each_entry(rel, list, head) {
+                u32 *addr = (u32 *)((unsigned long) cb + rel->offset);
                 if (likely(rel->res != NULL))
-                        cb[rel->offset] = rel->res->id;
+                        *addr = rel->res->id;
                 else
-                        cb[rel->offset] = SVGA_3D_CMD_NOP;
+                        *addr = SVGA_3D_CMD_NOP;
         }
 }
 
@@ -655,7 +667,8 @@ static int vmw_cmd_res_reloc_add(struct vmw_private *dev_priv,
         *p_val = NULL;
         ret = vmw_resource_relocation_add(&sw_context->res_relocations,
                                           res,
-                                          id_loc - sw_context->buf_start);
+                                          vmw_ptr_diff(sw_context->buf_start,
+                                                       id_loc));
         if (unlikely(ret != 0))
                 return ret;
 
@@ -721,7 +734,7 @@ vmw_cmd_res_check(struct vmw_private *dev_priv,
 
                 return vmw_resource_relocation_add
                         (&sw_context->res_relocations, res,
-                         id_loc - sw_context->buf_start);
+                         vmw_ptr_diff(sw_context->buf_start, id_loc));
         }
 
         ret = vmw_user_resource_lookup_handle(dev_priv,
@@ -2143,10 +2156,9 @@ static int vmw_cmd_shader_define(struct vmw_private *dev_priv,
                 return ret;
 
         return vmw_resource_relocation_add(&sw_context->res_relocations,
-                                           NULL, &cmd->header.id -
-                                           sw_context->buf_start);
-
-        return 0;
+                                           NULL,
+                                           vmw_ptr_diff(sw_context->buf_start,
+                                                        &cmd->header.id));
 }
 
 /**
@@ -2188,10 +2200,9 @@ static int vmw_cmd_shader_destroy(struct vmw_private *dev_priv,
                 return ret;
 
         return vmw_resource_relocation_add(&sw_context->res_relocations,
-                                           NULL, &cmd->header.id -
-                                           sw_context->buf_start);
-
-        return 0;
+                                           NULL,
+                                           vmw_ptr_diff(sw_context->buf_start,
+                                                        &cmd->header.id));
 }
 
 /**