The only way the debugger can handle a trap in inside rcu_lock,[...]
notify_die, or atomic_notifier_call_chain without a recursive fault is
to have a low level "first opportunity handler" do_trap_or_bp() handler.
Generally this will be something the vast majority of folks will not
need, but for those who need it, it is added as a kernel .config
option called KGDB_LOW_LEVEL_TRAP.
Also added was a die notification for oops such that kdb can catch an
oops for analysis.
There appeared to be no obvious way to pass the struct pt_regs from
the original exception back to the stack back tracer, so a special
case was added to show_stack() for when kdb is active because you
generally desire to generally look at the back trace of the original
exception.
CC: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Signed-off-by: Jason Wessel <jason.wessel@xxxxxxxxxxxxx>
---
arch/mips/include/asm/kgdb.h | 2 ++
arch/mips/kernel/kgdb.c | 22 +++++++++++++++++++++-
arch/mips/kernel/traps.c | 14 ++++++++++++++
lib/Kconfig.kgdb | 2 +-
+#include "../../../kernel/debug/kdb/kdb_private.h"