Commit 854700115ecf ([MIPS] kgdb: add arch support for the kernel's kgdb core)
added the 'kgdb_early_setup' flag to avoid  calling trap_init() and init_IRQ()
the second time, however the code that called these functions earlier,  from
kgdb_arch_init(), had been already removed by that  time,  so the flag never
served any useful purpose. Remove the related code along with ugly #ifdef'ery
at last.

[ralf@linux-mips.org: Folded in Guenter Roeck's fix.]
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Patchwork: https://patchwork.linux-mips.org/patch/10501/Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Patchwork: https://patchwork.linux-mips.org/patch/10533/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Implement the ability to individually get and set registers for kdb
and kgdb for mips.
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>
Acked-by: NRalf Baechle <ralf@linux-mips.org>
CC: linux-mips@linux-mips.org

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.
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>
Acked-by: NRalf Baechle <ralf@linux-mips.org>

Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

The new kgdb architecture specific handler registers and unregisters
dynamically for exceptions depending on when you configure a kgdb I/O
driver.

Aside from initializing the exceptions earlier in the boot process,
kgdb should have no impact on a device when it is compiled in so long
as an I/O module is not configured for use.

There have been quite a number of contributors during the existence of
this patch (see arch/mips/kernel/kgdb.c).  Most recently Jason
re-wrote the mips kgdb logic to use the die notification handlers.
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>