xen: strip /chosen/modules/module@<N>/* from dom0 device tree

These nodes are used by Xen to find the initial modules.

Only drop the "xen,multiboot-module" compatible nodes in case someone
else has a similar idea.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 6abbb03df44fe8f4a53e178fefe4efce0b658f27..512d78c6a37dffb8361b0c760d24cddfe9bd71c4 100644 (file)
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -172,6 +172,40 @@ static int write_properties(struct domain *d, struct kernel_info *kinfo,
     return prop;
 }
 
+/* Returns the next node in fdt (starting from offset) which should be
+ * passed through to dom0.
+ */
+static int fdt_next_dom0_node(const void *fdt, int node,
+                              int *depth_out,
+                              int parents[DEVICE_TREE_MAX_DEPTH])
+{
+    int depth = *depth_out;
+
+    while ( (node = fdt_next_node(fdt, node, &depth)) &&
+            node >= 0 && depth >= 0 )
+    {
+        if ( depth >= DEVICE_TREE_MAX_DEPTH )
+            break;
+
+        parents[depth] = node;
+
+        /* Skip /chosen/modules/module@<N>/ and all subnodes */
+        if ( depth >= 3 &&
+             device_tree_node_matches(fdt, parents[1], "chosen") &&
+             device_tree_node_matches(fdt, parents[2], "modules") &&
+             device_tree_node_matches(fdt, parents[3], "module") &&
+             fdt_node_check_compatible(fdt, parents[3],
+                                       "xen,multiboot-module" ) == 0 )
+            continue;
+
+        /* We've arrived at a node which dom0 is interested in. */
+        break;
+    }
+
+    *depth_out = depth;
+    return node;
+}
+
 static int write_nodes(struct domain *d, struct kernel_info *kinfo,
                        const void *fdt)
 {
@@ -179,11 +213,12 @@ static int write_nodes(struct domain *d, struct kernel_info *kinfo,
     int depth = 0, last_depth = -1;
     u32 address_cells[DEVICE_TREE_MAX_DEPTH];
     u32 size_cells[DEVICE_TREE_MAX_DEPTH];
+    int parents[DEVICE_TREE_MAX_DEPTH];
     int ret;
 
     for ( node = 0, depth = 0;
           node >= 0 && depth >= 0;
-          node = fdt_next_node(fdt, node, &depth) )
+          node = fdt_next_dom0_node(fdt, node, &depth, parents) )
     {
         const char *name;
 
@@ -191,7 +226,8 @@ static int write_nodes(struct domain *d, struct kernel_info *kinfo,
 
         if ( depth >= DEVICE_TREE_MAX_DEPTH )
         {
-            printk("warning: node `%s' is nested too deep\n", name);
+            printk("warning: node `%s' is nested too deep (%d)\n",
+                   name, depth);
             continue;
         }