Re: [PATCH] powerpc/8xx: add system_reset_exception

[Christophe Leroy]

Le 07/09/2016 Ã 00:40, Scott Wood a Ãcrit :
> On Mon, 2016-09-05 at 08:42 +0200, Christophe Leroy wrote:
> > When the watchdog is in NMI mode, the system reset interrupt is
> > generated when the watchdog counter expires.
> >
> > Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>
> > ---
> >  arch/powerpc/kernel/head_8xx.S | 2 +-
> >  arch/powerpc/kernel/traps.c    | 2 +-
> >  2 files changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
> > index 43ddaae..f7b8007 100644
> > --- a/arch/powerpc/kernel/head_8xx.S
> > +++ b/arch/powerpc/kernel/head_8xx.S
> > @@ -227,7 +227,7 @@ i##n:							
> > 	\
> >  			  ret_from_except)
> >
> >  /* System reset */
> > -	EXCEPTION(0x100, Reset, unknown_exception, EXC_XFER_STD)
> > +	EXCEPTION(0x100, Reset, system_reset_exception, EXC_XFER_STD)
>
> Does this do anything useful beyond what unknown_exception does?  Do you plan
> to have a ppc_md.system_reset_exception callback?

Yes that's the plan, having a platform specific callback to take 
emergency actions in order to speed up systemwise recovery, then restart 
the board.

In addition, unknown_exception doesn't show you that the exception comes 
from the NMI watchdog.

Christophe