Re: [Xen-devel] [PATCH 07/16] xen: arm: Handle cpus nodes with #address-calls > 1

[Julien Grall <julien.grall@xxxxxxxxxx>]

On 11/20/2013 04:37 PM, Ian Campbell wrote:
> On Wed, 2013-11-20 at 16:31 +0000, Julien Grall wrote:
>> On 11/20/2013 02:48 PM, Ian Campbell wrote:
>>> The APM X-Gene Mustang board DTS has #address-cells = 2.
>>>
>>> Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
>>> ---
>>>  xen/arch/arm/smpboot.c |   25 +++++++++++++++++++++----
>>>  1 file changed, 21 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/xen/arch/arm/smpboot.c b/xen/arch/arm/smpboot.c
>>> index 6c90fa6..ce832ae 100644
>>> --- a/xen/arch/arm/smpboot.c
>>> +++ b/xen/arch/arm/smpboot.c
>>> @@ -125,18 +125,35 @@ void __init smp_init_cpus(void)
>>>  
>>>      dt_for_each_child_node( cpus, cpu )
>>>      {
>>> +        const __be32 *prop;
>>> +        u64 addr, size;
>>>          u32 hwid;
>>>  
>>>          if ( !dt_device_type_is_equal(cpu, "cpu") )
>>>              continue;
>>>  
>>> -        if ( !dt_property_read_u32(cpu, "reg", &hwid) )
>>> +        if ( dt_n_size_cells(cpu) != 0 )
>>> +            printk(XENLOG_WARNING "cpu node `%s`: #size-cells %d\n",
>>> +                   dt_node_full_name(cpu), dt_n_size_cells(cpu));
>>> +
>>> +        prop = dt_get_property(cpu, "reg", NULL);
>>> +        if ( !prop )
>>>          {
>>> -            printk(XENLOG_WARNING "cpu node `%s`: missing reg property\n",
>>> +            printk(XENLOG_WARNING "cpu node `%s`: has no reg property\n",
>>>                     dt_node_full_name(cpu));
>>>              continue;
>>>          }
>>>  
>>> +        dt_get_range(&prop, cpu, &addr, &size);
>>
>> You can use dt_read_number here.
> 
> As in
>       dt_read_number(&prop, dt_n_addr_cells(cpu)
> ? Is there a helper which will take (&prop, cpu, &addr) and figure out
> the size etc internally, that's really what I was looking for.

Except dt_get_range, no. I would prefer the solution with dt_read_number
because it more clear that we want only a number. A cpu is not defined
by a range.

In the both case, you will also need to check the size of the property.
A bad crafted device tree can have reg smaller than #address-cells +
#size-cells.

-- 
Julien Grall

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