Re: [flashrom] [PATCH] Add support for SPARC (maybe).

[Stefan Tauner]

On Mon, 09 Feb 2015 23:19:11 +0100
Carl-Daniel Hailfinger  wrote:
> On 08.02.2015 22:16, Stefan Tauner wrote:
> > On Sun, 08 Feb 2015 17:55:10 +0100
> > Carl-Daniel Hailfinger  wrote:
> > > On 07.02.2015 19:49, Stefan Tauner wrote:
> > > > Was implemented by SPARC newbies, does (cross-)compile but is not run-tested.
> > > >
> > > > Signed-off-by: Stefan Tauner
> > >
> > > Thanks!
> > >
> > > Quoting wikipedia:
> > > > The endianness of the 32-bit SPARC V8 architecture is purely
> > > > big-endian. The 64-bit SPARC V9 architecture uses big-endian
> > > > instructions, but can access data in either big-endian or
> > > > little-endian byte order, chosen either at the application instruction
> > > > (load/store) level or at the memory page level (via an MMU setting).
> > > > The latter is often used for accessing data from inherently
> > > > little-endian devices, such as those on PCI buses.
> > >
> > > If that is true, we are totally screwed. How can we even begin to
> > > influence the instructions emitted by the compiler? And if the compiler
> > > emits bigendian instructions by default, can that be overridden via MMU
> > > setting? If yes, does Linux use the endianness manipulation via MMU for
> > > PCI devices, in which case we'd have to treat the architecture as
> > > littleendian from a flashrom POV?
> > >
> > > This is a nightmare.
> >
> > Only if you make it one. :)
> > Maybe this allows you to sleep better:
> > https://gcc.gnu.org/ml/gcc-patches/2011-10/msg02240.html
>
> Excellent, this means GCC won't try to screw us.
> > I am not sure if that "MMU settings" in wikipedia is referring to the
> > address space identifiers (ASIs), but it definitely screams [citation
> > needed]. 
> > In general the whole thing looks like a rather exotic if not esoteric
> > feature added to make porting Windows easier... in any case I am very
> > confident that it will not be encountered on real machines/OSes.
>
> Yay!
> > So... the only question is if you agree and we commit this before
> > tagging 0.9.8-rc1 or not. I don't care too much about SPARC support,
> > but I *do* care about getting the release out. Please respond in a
> > timely manner.
>
> With all this info and your excellent explanations on IRC, I want to say
> Thank You!
> Acked-by: Carl-Daniel Hailfinger

Let's hope I am correct. :)
Thanks, committed in r1882.