[Skiboot] [PATCH v10 00/31] little endian skiboot

Nicholas Piggin npiggin at gmail.com
Tue Jan 21 22:33:06 AEDT 2020

Oliver O'Halloran's on January 20, 2020 4:21 pm:
> On Sun, Dec 8, 2019 at 11:24 PM Nicholas Piggin <npiggin at gmail.com> wrote:
>> A few reasons for this:
>> - The rest of the software is moving (moved) to LE. BE is still
>>   supported, but the fact is LE will be better tested from now on in
>>   terms of toolchain.
>> - ELFv2 ABI is a smaller image, nicer asm code. We can use ELFv2 with BE
>>   but toolchain won't officially support or test it.
>> - Some levels of OpenPOWER ISA allow a conforming implementation to
>>   implement LE only.
>> - Less stack usage of ELFv2 facilitates OPAL call convention that uses
>>   the host kernel stack (which is a whole different story but has
>>   benefits).
>> - Common endian with the host kernel can help with debugging skiboot
>>   with host kernel facilities (like BUG, xmon). We could achieve the
>>   same by teaching kernel about different endianness, but it's more work.
> Thanks, merged to master as 266573939475c2ad4c93182a0775b8aaff348642
> Going forwards we probably want some more CI to check for BE vs LE
> regressions. I'm not too sure what to do there other than more boot
> testing though.

Booting to Linux should be a pretty good start for CI if you have
some PHB and XIVE. Beyond that there's a lot of obscure and/or crufty
features that'll be hard to get tested without flipping the default
I guess.


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