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kdb: Add support for external NMI handler to call KGDB/KDB

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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>
This commit is contained in:
Mike Travis
2013-10-02 10:14:18 -05:00
committed by Ingo Molnar
parent 8a1f4653f2
commit 8daaa5f826
6 changed files with 42 additions and 3 deletions
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5
kernel/debug/kdb/kdb_debugger.c
View File

@@ -69,7 +69,10 @@ int kdb_stub(struct kgdb_state *ks)
if (atomic_read(&kgdb_setting_breakpoint))
reason = KDB_REASON_KEYBOARD;
if (in_nmi())
if (ks->err_code == KDB_REASON_SYSTEM_NMI && ks->signo == SIGTRAP)
reason = KDB_REASON_SYSTEM_NMI;
else if (in_nmi())
reason = KDB_REASON_NMI;
for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++) {

3
kernel/debug/kdb/kdb_main.c
View File

@@ -1200,6 +1200,9 @@ static int kdb_local(kdb_reason_t reason, int error, struct pt_regs *regs,
instruction_pointer(regs));
kdb_dumpregs(regs);
break;
case KDB_REASON_SYSTEM_NMI:
kdb_printf("due to System NonMaskable Interrupt\n");
break;
case KDB_REASON_NMI:
kdb_printf("due to NonMaskable Interrupt @ "
kdb_machreg_fmt "\n",