[XEN][PATCH v12 01/20] common/device_tree: handle memory allocation failure in __unflatten_device_tree()

[Vikram Garhwal <vikram.garhwal@xxxxxxx>]

Change __unflatten_device_tree() return type to integer so it can propagate
memory allocation failure. Add panic() in dt_unflatten_host_device_tree() for
memory allocation failure during boot.

Fixes: fb97eb614acf ("xen/arm: Create a hierarchical device tree")
Signed-off-by: Vikram Garhwal <vikram.garhwal@xxxxxxx>
Reviewed-by: Henry Wang <Henry.Wang@xxxxxxx>
Reviewed-by: Michal Orzel <michal.orzel@xxxxxxx>
Acked-by: Julien Grall <jgrall@xxxxxxxxxx>

---
Changes from v9:
    Update comment regarding return value of unflatten_device_tree().
---
---
 xen/common/device_tree.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
index 0522fdf976..7c6b41c3b4 100644
--- a/xen/common/device_tree.c
+++ b/xen/common/device_tree.c
@@ -2091,9 +2091,11 @@ static unsigned long __init unflatten_dt_node(const void 
*fdt,
  * can be used.
  * @fdt: The fdt to expand
  * @mynodes: The device_node tree created by the call
+ *
+ * Returns 0 on success and a negative number on error
  */
-static void __init __unflatten_device_tree(const void *fdt,
-                                           struct dt_device_node **mynodes)
+static int __init __unflatten_device_tree(const void *fdt,
+                                          struct dt_device_node **mynodes)
 {
     unsigned long start, mem, size;
     struct dt_device_node **allnextp = mynodes;
@@ -2114,6 +2116,8 @@ static void __init __unflatten_device_tree(const void 
*fdt,
 
     /* Allocate memory for the expanded device tree */
     mem = (unsigned long)_xmalloc (size + 4, __alignof__(struct 
dt_device_node));
+    if ( !mem )
+        return -ENOMEM;
 
     ((__be32 *)mem)[size / 4] = cpu_to_be32(0xdeadbeefU);
 
@@ -2131,6 +2135,8 @@ static void __init __unflatten_device_tree(const void 
*fdt,
     *allnextp = NULL;
 
     dt_dprintk(" <- unflatten_device_tree()\n");
+
+    return 0;
 }
 
 static void dt_alias_add(struct dt_alias_prop *ap,
@@ -2215,7 +2221,11 @@ dt_find_interrupt_controller(const struct 
dt_device_match *matches)
 
 void __init dt_unflatten_host_device_tree(void)
 {
-    __unflatten_device_tree(device_tree_flattened, &dt_host);
+    int error = __unflatten_device_tree(device_tree_flattened, &dt_host);
+
+    if ( error )
+        panic("__unflatten_device_tree failed with error %d\n", error);
+
     dt_alias_scan();
 }
 
-- 
2.17.1