[PATCH v5 2/4] AArch64: KGDB: Add Basic KGDB support

[Will Deacon]

On Tue, Dec 03, 2013 at 11:21:39AM +0000, Will Deacon wrote:
> On Tue, Dec 03, 2013 at 10:16:37AM +0000, Mark Rutland wrote:
> > I think that there's a slight problem with this on BE systems.
> 
> [...]
> 
> > On Sat, Nov 30, 2013 at 06:32:26AM +0000, vijay.kilari at gmail.com wrote:
> > > +       { "pstate", 4, offsetof(struct pt_regs, pstate)},
> > 
> > As pt_regs::pstate is a u64, we're only describing half of the field
> > here (to match GDB's expectations). While we happen to get the half
> > we're interested in on an LE system, on a BE system this will point at
> > the zeroed half.
> 
> Yup, I think you're right. It's almost as if this hasn't been tested on a BE
> system.
> 
> Given that a large proportion of this CC list *do* actually care about BE,
> I'd like to see a tested-by from one of them before this gets merged. I'm
> pretty sure GDB has a testsuite which might be of some use.

Having said that, our ptrace interface (built around regsets) treats pstate
as 64-bit, so we should do the same thing for kgdb and let GDB work out
which bits it's interested in.

So: make pstate 8 bytes and test/fix GDB to deal with that (like it should
do for userspace already).

Will