kdb: Add support for external NMI handler to call KGDB/KDB
authorMike Travis <travis@sgi.com>
Wed, 2 Oct 2013 15:14:18 +0000 (10:14 -0500)
committerIngo Molnar <mingo@kernel.org>
Thu, 3 Oct 2013 16:47:54 +0000 (18:47 +0200)
commit8daaa5f8261bffd2f6217a960f9182d0503a5c44
tree2792d0b81d4165f234ffa22ea53b9a85d2819724
parent8a1f4653f27ffd5d61088cf6b95c39bb13bf6132
kdb: Add support for external NMI handler to call KGDB/KDB

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@sgi.com>
Acked-by: Jason Wessel <jason.wessel@windriver.com>
Reviewed-by: Dimitri Sivanich <sivanich@sgi.com>
Reviewed-by: Hedi Berriche <hedi@sgi.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Link: http://lkml.kernel.org/r/20131002151417.928886849@asylum.americas.sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
include/linux/kdb.h
include/linux/kgdb.h
kernel/debug/debug_core.c
kernel/debug/debug_core.h
kernel/debug/kdb/kdb_debugger.c
kernel/debug/kdb/kdb_main.c