xen/arm: check for multiboot nodes only under /chosen

Make sure to only look for multiboot compatible nodes only under
/chosen, not under any other paths (depth <= 3).

Signed-off-by: Stefano Stabellini <stefanos@xilinx.com>
[julien: Use sizeof(path) instead of len ]
Reviewed-by: Julien Grall <julien.grall@arm.com>

xen/arch/arm/bootfdt.c

@@ -174,6 +174,14 @@ static void __init process_multiboot_node(const void *fdt, int node,
     paddr_t start, size;
     const char *cmdline;
     int len;
+    /* sizeof("/chosen/") + DT_MAX_NAME + '/' + DT_MAX_NAME + '/0' => 92 */
+    char path[92];
+    int ret;
+
+    /* Check that the node is under "/chosen" (first 7 chars of path) */
+    ret = fdt_get_path(fdt, node, path, sizeof (path));
+    if ( ret != 0 || strncmp(path, "/chosen", 7) )
+        return;
 
     prop = fdt_get_property(fdt, node, "reg", &len);
     if ( !prop )
@@ -286,8 +294,8 @@ static int __init early_scan_node(const void *fdt,
 {
     if ( device_tree_node_matches(fdt, node, "memory") )
         process_memory_node(fdt, node, name, address_cells, size_cells);
-    else if ( device_tree_node_compatible(fdt, node, "xen,multiboot-module" ) ||
-              device_tree_node_compatible(fdt, node, "multiboot,module" ))
+    else if ( depth <= 3 && (device_tree_node_compatible(fdt, node, "xen,multiboot-module" ) ||
+              device_tree_node_compatible(fdt, node, "multiboot,module" )))
         process_multiboot_node(fdt, node, name, address_cells, size_cells);
     else if ( depth == 1 && device_tree_node_matches(fdt, node, "chosen") )
         process_chosen_node(fdt, node, name, address_cells, size_cells);