[PATCH v6 0/3] AArch64: KGDB support

[Will Deacon]

On Wed, Jan 22, 2014 at 07:50:46AM +0000, Vijay Kilari wrote:
> On Wed, Jan 22, 2014 at 10:01 AM, Vijay Kilari <vijay.kilari at gmail.com> wrote:
> >>> On Mon, Jan 20, 2014 at 3:53 PM, Will Deacon <will.deacon at arm.com> wrote:
> >> That's a good point: I think we wait until our first exception before they
> >> are unmasked. Perhaps we should:
> >>
> >>  (1) Move local_dbg_{save,restore} from debug-monitors.h into irqflags.h
> 
> local_dbg_save is setting bit #8 it should be bit #9?
> 
> #define local_dbg_save(flags)
>          \
>         do {
>          \
>                 typecheck(unsigned long, flags);
>          \
>                 asm volatile(
>          \
>                 "mrs    %0, daif                        //
> local_dbg_save\n"    \
>                 "msr    daifset, #8"

That uses daifset, so #8 is bit 3 which is D.

> >>  (2) Add local_dbg_enable/local_dbg_disable macros
> >>  (3) Add a call to local_dbg_enable in the clear_os_lock function after the
> >>      isb().
> >>
> >> Does that work for you?
> >
> > Yes, only after first exception occurs the PSTATE.D is unmasked.
> >
> > I have patched (temp) as below and now KGDB boot tests pass
> >
> > diff --git a/arch/arm64/include/asm/debug-monitors.h
> > b/arch/arm64/include/asm/debug-monitors.h
> > index aff3a76..ea2bc46 100644
> > --- a/arch/arm64/include/asm/debug-monitors.h
> > +++ b/arch/arm64/include/asm/debug-monitors.h
> > @@ -64,6 +111,24 @@ struct task_struct;
> >
> >  #define DBG_ARCH_ID_RESERVED   0       /* In case of ptrace ABI updates. */
> >
> > +#define local_dbg_enable()
> >          \
> > +       do {
> >          \
> > +               asm volatile(
> >          \
> > +               "msr    daifclr, #9             //

I think this is going to unmask fiq as well...

Will