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

[Vijay Kilari]

On Tue, Dec 3, 2013 at 7:08 PM, Will Deacon <will.deacon at arm.com> wrote:
> 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).
>

I have tested with BE & LE. it works fine except displaying 'pstate' contents
in BE is wrong

If I change pstate offset as below, it works

#ifdef __AARCH64EB__
        { "pstate", 4, offsetof(struct pt_regs, pstate) + 4},
#else
        { "pstate", 4, offsetof(struct pt_regs, pstate)},
#endif

I am checking with tool chain guy to patch GDB to make pstate as 8 bytes.
After that, I will re-send the patch series

> Will