Commit 6426e8d1 authored by Douglas Anderson's avatar Douglas Anderson Committed by Andrew Morton
Browse files

watchdog/hardlockup: HAVE_NMI_WATCHDOG must implement watchdog_hardlockup_probe() 

Right now there is one arch (sparc64) that selects HAVE_NMI_WATCHDOG
without selecting HAVE_HARDLOCKUP_DETECTOR_ARCH.  Because of that one
architecture, we have some special case code in the watchdog core to
handle the fact that watchdog_hardlockup_probe() isn't implemented.

Let's implement watchdog_hardlockup_probe() for sparc64 and get rid of the
special case.

As a side effect of doing this, code inspection tells us that we could fix
a minor bug where the system won't properly realize that NMI watchdogs are
disabled.  Specifically, on powerpc if CONFIG_PPC_WATCHDOG is turned off
the arch might still select CONFIG_HAVE_HARDLOCKUP_DETECTOR_ARCH which
selects CONFIG_HAVE_NMI_WATCHDOG.  Since CONFIG_PPC_WATCHDOG was off then
nothing will override the "weak" watchdog_hardlockup_probe() and we'll
fallback to looking at CONFIG_HAVE_NMI_WATCHDOG.

Link: https://lkml.kernel.org/r/20230526184139.2.Ic6ebbf307ca0efe91f08ce2c1eb4a037ba6b0700@changeid


Signed-off-by: default avatarDouglas Anderson <dianders@chromium.org>
Suggested-by: default avatarPetr Mladek <pmladek@suse.com>
Reviewed-by: default avatarPetr Mladek <pmladek@suse.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 9ec272c5

arch/Kconfig

+2 −1
Original line number Original line Diff line number Diff line
@@ -405,7 +405,8 @@ config HAVE_NMI_WATCHDOG 
	bool

	bool

	help

	help

	  The arch provides a low level NMI watchdog. It provides

	  The arch provides a low level NMI watchdog. It provides

	  asm/nmi.h, and defines its own arch_touch_nmi_watchdog().

	  asm/nmi.h, and defines its own watchdog_hardlockup_probe() and

	  arch_touch_nmi_watchdog().





config HAVE_HARDLOCKUP_DETECTOR_ARCH

config HAVE_HARDLOCKUP_DETECTOR_ARCH

	bool

	bool

arch/sparc/kernel/nmi.c

+5 −0
Original line number Original line Diff line number Diff line
@@ -65,6 +65,11 @@ void arch_touch_nmi_watchdog(void) 
}

}

EXPORT_SYMBOL(arch_touch_nmi_watchdog);

EXPORT_SYMBOL(arch_touch_nmi_watchdog);





int __init watchdog_hardlockup_probe(void)

{

	return 0;

}



static void die_nmi(const char *str, struct pt_regs *regs, int do_panic)

static void die_nmi(const char *str, struct pt_regs *regs, int do_panic)

{

{

	int this_cpu = smp_processor_id();

	int this_cpu = smp_processor_id();

kernel/watchdog.c

+0 −13
Original line number Original line Diff line number Diff line
@@ -217,19 +217,6 @@ void __weak watchdog_hardlockup_disable(unsigned int cpu) { } 
 */

 */

int __weak __init watchdog_hardlockup_probe(void)

int __weak __init watchdog_hardlockup_probe(void)

{

{

	/*

	 * If CONFIG_HAVE_NMI_WATCHDOG is defined then an architecture

	 * is assumed to have the hard watchdog available and we return 0.

	 */

	if (IS_ENABLED(CONFIG_HAVE_NMI_WATCHDOG))

		return 0;



	/*

	 * Hardlockup detectors other than those using CONFIG_HAVE_NMI_WATCHDOG

	 * are required to implement a non-weak version of this probe function

	 * to tell whether they are available. If they don't override then

	 * we'll return -ENODEV.

	 */

	return -ENODEV;

	return -ENODEV;

}

}