Re: [XEN][PATCH v7 01/19] common/device_tree: handle memory allocation failure in __unflatten_device_tree()

[Julien Grall]

Hi,

On 02/06/2023 01:48, Vikram Garhwal wrote:

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.garh...@amd.com>

With Michal's remark handled (it can be done on commit):

Acked-by: Julien Grall <jgr...@amazon.com>

Cheers,

Reviewed-by: Henry Wang <henry.w...@arm.com>
---
  xen/common/device_tree.c | 14 +++++++++++---
  1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
index 8da1052911..dfdb10e488 100644
--- a/xen/common/device_tree.c
+++ b/xen/common/device_tree.c
@@ -2092,8 +2092,8 @@ static unsigned long __init unflatten_dt_node(const void 
*fdt,
   * @fdt: The fdt to expand
   * @mynodes: The device_node tree created by the call
   */
-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 +2114,8 @@ 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(0xdeadbeef); @@ -2131,6 +2133,8 @@ 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 +2219,11 @@ 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();
  }

--
Julien Grall