Re: [PATCH 9/9] arm: initial drop

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On Thu, Jan 02, 2014 at 10:09:50AM -0800, Christoffer Dall wrote:
> On Thu, Jan 02, 2014 at 05:40:24PM +0000, Peter Maydell wrote:
> > On 2 January 2014 16:54, Andrew Jones <drjones@xxxxxxxxxx> wrote:
> > > On Sat, Dec 28, 2013 at 10:31:35PM -0800, Christoffer Dall wrote:
> > >> On Wed, Dec 04, 2013 at 05:42:57PM +0100, Andrew Jones wrote:
> > >> > +   ands    r3, r8, #CR_B           @set BE, if necessary
> > >> > +   ldrne   r3, =cpu_is_be
> > >> > +   movne   r4, #1
> > >>
> > >> This is deprecated for ARMv7 according to the ARM ARM.  What is the
> > >> intention here?  Does qemu support running this test tool with the
> > >> system configured for big-endian?  If so, I think this is a build option
> > >> for this binary or you need to come up with some other
> > >> architecture-compliant method of detecting the endian-state.
> > >
> > > Yes, qemu allows big-endian. I haven't tested it though, but suspect
> > > someday we will want big-endian guests tested as well. I'll fix the
> > > detection.
> > 
> > QEMU does not support system mode big-endian. (Some of the
> > pieces are there for it but we have no board that needs it.)
> > 
> > Also, you should read up in the ARM ARM about the differences
> > between old style BE32 and new BE8. (The quick summary is here:
> > http://translatedcode.wordpress.com/2012/04/)
> > What you're trying to do here is enable old-style BE32. This is
> > not supported on any ARMv7 or later CPU, which means it does
> > not overlap at all with virtualization support.
> > 
> > We probably do care about BE8 big-endian guest support testing.
> > (kvmtool can run guests in this mode; QEMU doesn't currently).
> > 
> Yeah, so I think this logic should go away from the test suite for now,
> focs on getting a decent set of actual functional tests up and running,
> and then probably add aarch64 support before looking at big-endian
> support.
>

OK, sounds good. The cpu_is_be stuff scattered about should still be fine
to leave in, and we can go about actually detecting BE and setting
cpu_is_be whenever.

thanks,
drew
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