Re: [PATCH 4/8] device-tree: get_val cannot cope with cells > 2, add early_panic

[David Vrabel <david.vrabel@citrix.com>]

On 03/12/12 17:10, Ian Campbell wrote:
> Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
> ---
> v3: early_panic instead of BUG_ON
> v2: drop unrelated white space fixup
> ---
>  xen/common/device_tree.c |    3 +++
>  1 files changed, 3 insertions(+), 0 deletions(-)
> 
> diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
> index 9eb316f..5a0a1a6 100644
> --- a/xen/common/device_tree.c
> +++ b/xen/common/device_tree.c
> @@ -58,6 +58,9 @@ static void __init get_val(const u32 **cell, u32 cells, u64 *val)
>  {
>      *val = 0;
>  
> +    if ( cells > 2 )
> +        early_panic("dtb value contains > 2 cells\n");
> +

This seems like overkill to me.  get_val() truncates the value down to
64 bits which is fine as no valid physical address is more than 64 bits.

I think the device tree parsing code should try to continue as much as
possible if it gets a DTB that looks a bit funny.

David