On Tue, 24 Oct 2017 20:20:05 +1100
Michael Neuling <mi...@neuling.org> wrote:
> On an unrecoverable HMI or MCE only generate an checkstop (via
> PLATFORM ERROR opal reboot call) when panic_on_oops is set.
>
> We currently generate an checkstop as an attempt for the FSP to grab a
> dump and then reboot us. Unfortunately this never works and no one
> I've talked to has ever seen a resulting dump, let alone got useful
> information from it.
>
> Even worse, the checkstop gets in the way of debugging real
> problems. If we hit a software bug that results in this, we get no
> opportunity to debug it live. Similarly if the bug is due to hardware
> that is not in the dump (say PCI or NVLINK GPU), we get no information
> in the dump about that hardware.
>
> So let's remove it unless someone sets panic_on_oops.
>
> Signed-off-by: Michael Neuling <mi...@neuling.org>
> ---
> arch/powerpc/platforms/powernv/opal-hmi.c | 6 ++++++
> arch/powerpc/platforms/powernv/opal.c | 4 ++++
> 2 files changed, 10 insertions(+)
>
> diff --git a/arch/powerpc/platforms/powernv/opal-hmi.c
> b/arch/powerpc/platforms/powernv/opal-hmi.c
> index c9e1a4ff29..23780970d0 100644
> --- a/arch/powerpc/platforms/powernv/opal-hmi.c
> +++ b/arch/powerpc/platforms/powernv/opal-hmi.c
> @@ -29,6 +29,7 @@
> #include <asm/opal.h>
> #include <asm/cputable.h>
> #include <asm/machdep.h>
> +#include <asm/bug.h>
>
> #include "powernv.h"
>
> @@ -284,6 +285,11 @@ static void hmi_event_handler(struct work_struct *work)
> print_hmi_event_info(hmi_evt);
> }
>
> + if (!panic_on_oops) {
> + die("Unrecoverable HMI exception", NULL, SIGBUS);
> + return;
> + }
> +
If panic_on_oops is set, we checkstop, not panic! Passing NULL to die, will
cause arch_uprobe_exception_notify() to complain.
We could respin this a bit and I can send an updated patch if there is interest
Balbir Singh.
