[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH V1 11/29] xen/dts: Check "reg" property length in process_multiboot_node
On 09/06/2013 05:40 PM, Ian Campbell wrote: On Wed, 2013-08-28 at 15:47 +0100, Julien Grall wrote:When the device tree compiler (dtc) can't find right #address-cells and #size-cells, it will assume the encoding is 1 for each.Without inserting them into the DTB I suppose? Yes. I have noticed that the encoding is not 1 for each but"If missing, a client program should assume a default value of 2 for #address-cells, and a value of 1 for #size-cells." (ePAR 2.3.5) dtc will warns with the following messages:Warning (reg_format): "reg" property in /chosen/modules/module@0 has invalid length (8 bytes) (#address-cells == 2, #size-cells == 1) Warning (avoid_default_addr_size): Relying on default #address-cells value for /chosen/modules/module@0 Warning (avoid_default_addr_size): Relying on default #size-cells value for /chosen/modules/module@0 As multiboot node are inside the /chosen, dtc will asume the previous values"assume"if the both property are not correct set."the both property" => "both properties" and "correctly" By "previous values" do you mean the values set in the (grand)parent node? Yes. I will update the comment. During boot, Xen will browse the fdt and store the nearest #address-cells and #size-cells value. If the size of "reg" is smaller, Xen can retrieve wrong range.How come Xen can find a suitable #address-cells but dtc cannot? Are we not handling them correctly perhaps? So we have two issues: 1) Xen doesn't check the length of the reg property (this patch) 2) Default value for #address-cells and #size-cells are wrong Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx> --- xen/common/device_tree.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c index 9568250..7295f34 100644 --- a/xen/common/device_tree.c +++ b/xen/common/device_tree.c @@ -467,10 +467,14 @@ static void __init process_multiboot_node(const void *fdt, int node, mod = &early_info.modules.module[nr]; - prop = fdt_get_property(fdt, node, "reg", NULL); + prop = fdt_get_property(fdt, node, "reg", &len); if ( !prop ) early_panic("node %s missing `reg' property\n", name); + if ( len < dt_cells_to_size(address_cells + size_cells) ) + early_panic("fdt: node `%s': `reg` property length is too short\n", + name); + cell = (const u32 *)prop->data; device_tree_get_reg(&cell, address_cells, size_cells, &mod->start, &mod->size); -- Julien Grall _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
|
Lists.xenproject.org is hosted with RackSpace, monitoring our |