Re: [PATCH 5/7] KGDB/KDB: add support for external NMI handler tocall KGDB/KDB.

From: Ingo Molnar
Date: Tue Sep 24 2013 - 04:15:56 EST



* Mike Travis <travis@xxxxxxx> wrote:

> This patch adds a kgdb_nmicallin() interface that can be used by
> external NMI handlers to call the KGDB/KDB handler. The primary need
> for this is for those types of NMI interrupts where all the CPUs
> have already received the NMI signal. Therefore no send_IPI(NMI)
> is required, and in fact it will cause a 2nd unhandled NMI to occur.
> This generates the "Dazed and Confuzed" messages.
>
> Since all the CPUs are getting the NMI at roughly the same time, it's not
> guaranteed that the first CPU that hits the NMI handler will manage to
> enter KGDB and set the dbg_master_lock before the slaves start entering.
> The new argument "send_ready" was added for KGDB to signal the NMI handler
> to release the slave CPUs for entry into KGDB.
>
> Signed-off-by: Mike Travis <travis@xxxxxxx>
> Reviewed-by: Dimitri Sivanich <sivanich@xxxxxxx>
> Reviewed-by: Hedi Berriche <hedi@xxxxxxx>
> ---
> include/linux/kdb.h | 1 +
> include/linux/kgdb.h | 1 +
> kernel/debug/debug_core.c | 30 +++++++++++++++++++++++++++++-
> kernel/debug/debug_core.h | 1 +
> kernel/debug/kdb/kdb_debugger.c | 5 ++++-
> kernel/debug/kdb/kdb_main.c | 3 +++
> 6 files changed, 39 insertions(+), 2 deletions(-)

Jason, any objections to form or substance of this callback?

Thanks,

Ingo
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