Re: Improve support for genkernel in 10_linux

[Mike Gilbert]

2012/4/18 Vladimir 'φ-coder/phcoder' Serbinenko <address@hidden>:
> On 15.04.2012 04:21, Mike Gilbert wrote:
>> On 04/11/2012 11:52 AM, Mike Gilbert wrote:
>>> 2012/4/11 Vladimir 'φ-coder/phcoder' Serbinenko <address@hidden>:
>>>> On 11.04.2012 04:56, Mike Gilbert wrote:
>>>>> On 04/07/2012 05:54 PM, Mike Gilbert wrote:
>>>>>> Secondly, genkernel looks for the "real_root" kernel command line option
>>>>>> to determine the root filesystem. This is a holdover from the days when
>>>>>> we used true initrd images and we needed to use root=/dev/ram0.
>>>>>>
>>>>> It was brought to my attention that genkernel's initramfs code will in
>>>>> fact utilize "root" if "real_root" is unset. This part of my previous
>>>>> patch is therefore pointless.
>>>>>
>>>>> I have attached a revised patch containing only the changes necessary to
>>>>> detect a genkernel initramfs image.
>>>>>
>>>> pushd/popd isn't POSIX so we can't use it in our scripts. Also I don't
>>>> feel like glob expansion is the right thing to use here. Why not infer
>>>> the architecture from uname ?
>>> That should also work. Here's the logic that genkernel uses to populate 
>>> ARCH:
>>>
>>> ARCH=`uname -m`
>>> case "${ARCH}" in
>>>      i?86)
>>>              ARCH="x86"
>>>              ;;
>>>      mips|mips64)
>>>              ARCH="mips"
>>>              ;;
>>>      arm*)
>>>              ARCH=arm
>>>              ;;
>>>      *)
>>>              ;;
>>> esac
>>>
>>> I'm thinking it would be a good idea to rename ARCH to something like
>>> GENKERNEL_ARCH. We should also let the user override this in
>>> /etc/default/grub.
>>>
>>> Does that sound ok?
>> I have modified my patch to implement what I describe above.
>>
> What is the reason to make it configurable? There shouldn't be any need
> to configure something that is autodetected
>

genkernel allows the user to cross-compile their kernel and/or
initramfs, in which case uname -m would not provide the correct value.

I don't have a clear picture in my mind of how that would work with
grub, but I figure it would be better to err on the side of
flexibility.