Re: Design doc of adding ACPI support for arm64 on Xen - version 3

[Julien Grall <julien.grall@citrix.com>]

Hi,

On 17/08/2015 06:01, Shannon Zhao wrote:
>
>
> On 2015/8/14 23:17, Julien Grall wrote:
>> On 14/08/15 15:59, Shannon Zhao wrote:
>>> 2. Create minimal DT to pass required information to Dom0
>>> ----------------------------------------------------------
>>> The minimal DT mainly passes Dom0 bootargs, address and size of initrd
>>> (if available), address and size of uefi system table, address and size
>>> of uefi memory table, uefi-mmap-desc-size and uefi-mmap-desc-ver.
>>>
>>> An example of the minimal DT:
>>> / {
>>>      #address-cells = <2>;
>>>      #size-cells = <1>;
>>>      chosen {
>>>          bootargs = "kernel=Image console=hvc0 earlycon=pl011,0x1c090000
>>> root=/dev/vda2 rw rootfstype=ext4 init=/bin/sh acpi=force";
>>>          linux,initrd-start = <0xXXXXXXXX>;
>>>          linux,initrd-end = <0xXXXXXXXX>;
>>>          linux,uefi-system-table = <0xXXXXXXXX>;
>>>          linux,uefi-mmap-start = <0xXXXXXXXX>;
>>>          linux,uefi-mmap-size = <0xXXXXXXXX>;
>>>          linux,uefi-mmap-desc-size = <0xXXXXXXXX>;
>>>          linux,uefi-mmap-desc-ver = <0xXXXXXXXX>;
>>>      };
>>> };
>>>
>>> For details loook at
>>> https://github.com/torvalds/linux/blob/master/Documentation/arm/uefi.txt
>>
>> I would have expect a summary on the discussion we had on the previous
>> thread [1].
>>
>> Note that "linux,initrd-*" are well defined given that Xen, U-boot and
>> other bootloaders are using them. And IIRC, it's Linux specific.
>>
>> Although, "linux,uefi-*" are not well defined (only used internally by
>> Linux betwen the EFI stub and the kernel) and we expect other OS to use
>> them in the future.
>>
>> So I would prefer to the "linux," dropped for them.
>>
>
> Yes, I think it's good to drop the "linux," too. But if we drop the
> linux, would it impact the linux kernel booting with UEFI? And why we
> don't do it to Xen since Xen still uses "linux,"?

I don't understand your second question.

For the first question, as we discussed in several mail, the property 
"linux,uefi-*" are only used internally between the stub and Linux. The 
sub is compiled in the kernel so there is no issue to change the property.

Regards,

-- 
Julien Grall