[Xen-devel] [PATCH v7 3/4] xen: strip xen, multiboot-module nodes from dom0 device tree

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

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

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
Acked-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
---
v6 - filter based on compatibility node name and not path.
v4 - /chosen/modules/modules@N not /chosen/module@N
v3 - use a helper to filter out DT elements which are not for dom0.
     Better than an ad-hoc break in the middle of a loop.
---
 xen/arch/arm/domain_build.c |   32 ++++++++++++++++++++++++++++++--
 1 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 9ce661b..1c35c82 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -172,6 +172,33 @@ 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 depth = *depth_out;
+
+    while ( (node = fdt_next_node(fdt, node, &depth)) &&
+            node >= 0 && depth >= 0 )
+    {
+        if ( depth >= DEVICE_TREE_MAX_DEPTH )
+            break;
+
+        /* Skip multiboot subnodes */
+        if ( fdt_node_check_compatible(fdt, node,
+                                       "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)
 {
@@ -183,7 +210,7 @@ static int write_nodes(struct domain *d, struct kernel_info 
*kinfo,
 
     for ( node = 0, depth = 0;
           node >= 0 && depth >= 0;
-          node = fdt_next_node(fdt, node, &depth) )
+          node = fdt_next_dom0_node(fdt, node, &depth) )
     {
         const char *name;
 
@@ -191,7 +218,8 @@ 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;
         }
 
-- 
1.7.9.1


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