[Qemu-devel] [PATCH] device_tree.c: Terminate the empty reservemap in create_device_tree()

[Qemu-devel] [PATCH] device_tree.c: Terminate the empty reservemap in create_device_tree()

[Peter Maydell]

Device trees created with create_device_tree() may not have any
entries in their reservemap, because the FDT API requires that the
reservemap is completed before any FDT nodes are added, and
create_device_tree() itself creates a node.  However we were not
calling fdt_finish_reservemap(), which meant that there was no
terminator in the reservemap list and whatever happened to be at the
start of the FDT data section would end up being interpreted as
reservemap entries.  Avoid this by calling fdt_finish_reservemap()
to add the terminator.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
On ARM this manifested as a DTB with
/memreserve/    0x0000000100000000 0x0000000200000009;
and my mach-virt test kernel wasn't booting as a result.

 device_tree.c |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/device_tree.c b/device_tree.c
index ffec99a..391da8c 100644
--- a/device_tree.c
+++ b/device_tree.c
@@ -41,6 +41,10 @@ void *create_device_tree(int *sizep)
     if (ret < 0) {
         goto fail;
     }
+    ret = fdt_finish_reservemap(fdt);
+    if (ret < 0) {
+        goto fail;
+    }
     ret = fdt_begin_node(fdt, "");
     if (ret < 0) {
         goto fail;
-- 
1.7.9.5

Re: [Qemu-devel] [PATCH] device_tree.c: Terminate the empty reservemap in create_device_tree()

[Alexander Graf]

On 10.09.2013, at 08:51, Peter Maydell wrote:

> Device trees created with create_device_tree() may not have any
> entries in their reservemap, because the FDT API requires that the
> reservemap is completed before any FDT nodes are added, and
> create_device_tree() itself creates a node.  However we were not
> calling fdt_finish_reservemap(), which meant that there was no
> terminator in the reservemap list and whatever happened to be at the
> start of the FDT data section would end up being interpreted as
> reservemap entries.  Avoid this by calling fdt_finish_reservemap()
> to add the terminator.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Acked-by: Alexander Graf <agraf@suse.de>

Peter C, will you take this into your tree?


Alex