Re: [PATCH v2 for-4.9] xen/arm: Don't unflatten DT when booting with ACPI

[Punit Agrawal <punit.agrawal@arm.com>]

Stefano Stabellini <sstabellini@kernel.org> writes:

> On Fri, 21 Apr 2017, Punit Agrawal wrote:
>> Unflattening the device tree when booting with "acpi=force" leads to the
>> following stack trace on AMD Seattle platform -
>> 
>> (XEN) Xen call trace:
>> (XEN)    [<0000000000204bfc>] dt_irq_translate+0x48/0x58 (PC)
>> (XEN)    [<0000000000204f5c>] dt_device_get_irq+0x34/0x38 (LR)
>> (XEN)    [<0000000000251a08>] platform_get_irq+0x14/0x44
>> (XEN)    [<00000000002952bc>] smmu.c#arm_smmu_dt_init+0x190/0x100c
>> (XEN)    [<0000000000299310>] device_init+0xa8/0xdc
>> (XEN)    [<00000000002950f0>] iommu_hardware_setup+0x34/0x68
>> (XEN)    [<0000000000294ef0>] iommu_setup+0x48/0x1c8
>> (XEN)    [<000000000029cecc>] start_xen+0xb94/0xd34
>> (XEN)    [<00000083fbba91dc>] 00000083fbba91dc
>> 
>> The problem arises due to the unflattened device tree being
>> unconditionally used in iommu_hardware_setup().
>> 
>> Let's re-arrange the code without changing boot order to unflatten the
>> device tree only when acpi is disabled.
>> 
>> Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
>> Reviewed-by: Julien Grall <julien.grall@arm.com>
>
>
> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
>
> and committed

Thanks Julien and Stefano for the quick turn around!

Cheers,
Punit

>
>
>> ---
>> v1 -> v2
>> * Changed tab to spaces
>> * Added tag
>> ---
>>  xen/arch/arm/setup.c | 12 +++++++-----
>>  1 file changed, 7 insertions(+), 5 deletions(-)
>> 
>> diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
>> index 92a2de6b70..046905f6c3 100644
>> --- a/xen/arch/arm/setup.c
>> +++ b/xen/arch/arm/setup.c
>> @@ -753,16 +753,18 @@ void __init start_xen(unsigned long boot_phys_offset,
>>      /* Parse the ACPI tables for possible boot-time configuration */
>>      acpi_boot_table_init();
>>  
>> +    end_boot_allocator();
>> +
>> +    vm_init();
>> +
>>      if ( acpi_disabled )
>> +    {
>>          printk("Booting using Device Tree\n");
>> +        dt_unflatten_host_device_tree();
>> +    }
>>      else
>>          printk("Booting using ACPI\n");
>>  
>> -    end_boot_allocator();
>> -
>> -    vm_init();
>> -    dt_unflatten_host_device_tree();
>> -
>>      init_IRQ();
>>  
>>      platform_init();
>> -- 
>> 2.11.0
>> 

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