arm64: enable perf events based hard lockup detector

With the recent feature added to enable perf events to use pseudo NMIs as
interrupts on platforms which support GICv3 or later, its now been
possible to enable hard lockup detector (or NMI watchdog) on arm64
platforms.  So enable corresponding support.

One thing to note here is that normally lockup detector is initialized
just after the early initcalls but PMU on arm64 comes up much later as
device_initcall().  To cope with that, override
arch_perf_nmi_is_available() to let the watchdog framework know PMU not
ready, and inform the framework to re-initialize lockup detection once PMU
has been initialized.

[dianders@chromium.org: only HAVE_HARDLOCKUP_DETECTOR_PERF if the PMU config is enabled]
  Link: https://lkml.kernel.org/r/20230523073952.1.I60217a63acc35621e13f10be16c0cd7c363caf8c@changeid
Link: https://lkml.kernel.org/r/20230519101840.v5.18.Ia44852044cdcb074f387e80df6b45e892965d4a1@changeid
Co-developed-by: Sumit Garg <sumit.garg@linaro.org>
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Co-developed-by: Pingfan Liu <kernelfans@gmail.com>
Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
Signed-off-by: Lecopzer Chen <lecopzer.chen@mediatek.com>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chen-Yu Tsai <wens@csie.org>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Colin Cross <ccross@android.com>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Guenter Roeck <groeck@chromium.org>
Cc: Ian Rogers <irogers@google.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masayoshi Mizuma <msys.mizuma@gmail.com>
Cc: Matthias Kaehlcke <mka@chromium.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com>
Cc: Ricardo Neri <ricardo.neri@intel.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Stephen Boyd <swboyd@chromium.org>
Cc: Tzung-Bi Shih <tzungbi@chromium.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 12 insertions, 0 deletions

diff --git a/arch/arm64/kernel/watchdog_hld.c b/arch/arm64/kernel/watchdog_hld.c
index 2401eb1b7e55..dcd25322127c 100644
--- a/arch/arm64/kernel/watchdog_hld.c
+++ b/arch/arm64/kernel/watchdog_hld.c
@@ -1,5 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
+#include <linux/nmi.h>
 #include <linux/cpufreq.h>
+#include <linux/perf/arm_pmu.h>
 
 /*
  * Safe maximum CPU frequency in case a particular platform doesn't implement
@@ -22,3 +24,13 @@ u64 hw_nmi_get_sample_period(int watchdog_thresh)
 
 	return (u64)max_cpu_freq * watchdog_thresh;
 }
+
+bool __init arch_perf_nmi_is_available(void)
+{
+	/*
+	 * hardlockup_detector_perf_init() will success even if Pseudo-NMI turns off,
+	 * however, the pmu interrupts will act like a normal interrupt instead of
+	 * NMI and the hardlockup detector would be broken.
+	 */
+	return arm_pmu_irq_is_nmi();
+}