Re: [Qemu-ppc] [Qemu-devel] [PATCH 3/3] configure: Add new target ppc64el-linux-user

[Tom Musta]

On 5/8/2014 10:25 AM, Peter Maydell wrote:
> On 8 May 2014 16:19, Doug Kwan (關振德) <address@hidden> wrote:
>> On Thu, May 8, 2014 at 7:41 AM, Tom Musta <address@hidden> wrote:
>>> We have TCG targets for PowerPC that are bi-endian. It would be much nicer
>>> to have to split
>>> user mode by endianness.  If the user loads a BE ELF, then run in BE mode
>>> .... a LE ELF,
>>> then run in LE mode.
>>>
>>> I know there is much hand waving in that statement ... but maybe we can do
>>> better?  ("we" includes
>>> "me" in that statement ... since I offered to Doug to help out with this).
> 
>> To do this, we need to fix the elf load.
> 
> That is far from the only thing that would need changing.
> I really don't recommend trying to do something different
> from the norm here.
> 
> Isn't LE PPC a different ABI anyway? (ELFv2).
> 
> thanks
> -- PMM
> 

It is true that the new LE distros are basing on ELFv2.  But ELFv2 ABI is not
limited to LE.  I chatted with Uli on this very topic and he confirmed that
endianness is specified in the e_ident field of the header.

I believe we have thoroughly demonstrated that the (softmmu) TCG code works
correctly in both settings of MSR[LE], without making compile time decisions.
It doesn't seem like we are that far off ... maybe I don't see the problem
yet.