This will be useful in dynamic node programming when new dt nodes are unflatten
during runtime. Invalid device tree node related errors should be propagated
back to the caller.

Signed-off-by: Vikram Garhwal <vikram.garhwal@amd.com>
---
 xen/common/device_tree.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
index 5daf5197bd..47ab2f7940 100644
--- a/xen/common/device_tree.c
+++ b/xen/common/device_tree.c
@@ -2071,6 +2071,9 @@ int unflatten_device_tree(const void *fdt, struct dt_device_node **mynodes)
     /* First pass, scan for size */
     start = ((unsigned long)fdt) + fdt_off_dt_struct(fdt);
     size = unflatten_dt_node(fdt, 0, &start, NULL, NULL, 0);
+    if ( !size )
+        return -EINVAL;
+
     size = (size | 3) + 1;
 
     dt_dprintk("  size is %#lx allocating...\n", size);
@@ -2088,11 +2091,19 @@ int unflatten_device_tree(const void *fdt, struct dt_device_node **mynodes)
     start = ((unsigned long)fdt) + fdt_off_dt_struct(fdt);
     unflatten_dt_node(fdt, mem, &start, NULL, &allnextp, 0);
     if ( be32_to_cpup((__be32 *)start) != FDT_END )
-        printk(XENLOG_WARNING "Weird tag at end of tree: %08x\n",
+    {
+        printk(XENLOG_ERR "Weird tag at end of tree: %08x\n",
                   *((u32 *)start));
+        return -EINVAL;
+    }
+
     if ( be32_to_cpu(((__be32 *)mem)[size / 4]) != 0xdeadbeef )
-        printk(XENLOG_WARNING "End of tree marker overwritten: %08x\n",
+    {
+        printk(XENLOG_ERR "End of tree marker overwritten: %08x\n",
                   be32_to_cpu(((__be32 *)mem)[size / 4]));
+        return -EINVAL;
+    }
+
     *allnextp = NULL;
 
     dt_dprintk(" <- unflatten_device_tree()\n");
-- 
2.17.1

Hi Vikram,

> -----Original Message-----
> Subject: [XEN][PATCH v6 04/19] common/device_tree.c:
> unflatten_device_tree() propagate errors
> 
> This will be useful in dynamic node programming when new dt nodes are
> unflatten

Typo: s/unflatten/unflattened/?

> during runtime. Invalid device tree node related errors should be propagated
> back to the caller.
> 
> Signed-off-by: Vikram Garhwal <vikram.garhwal@amd.com>

Reviewed-by: Henry Wang <Henry.Wang@arm.com>

Kind regards,
Henry