The patch titled
Subject: arm64: enable perf events based hard lockup detector
has been added to the -mm mm-nonmm-unstable branch. Its filename is
arm64-enable-perf-events-based-hard-lockup-detector.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/arm64-enable-perf-events-based-hard-lockup-detector.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Douglas Anderson <dianders@xxxxxxxxxxxx>
Subject: arm64: enable perf events based hard lockup detector
Date: Fri, 19 May 2023 10:18:42 -0700
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.
Link: https://lkml.kernel.org/r/20230519101840.v5.18.Ia44852044cdcb074f387e80df6b45e892965d4a1@changeid
Co-developed-by: Sumit Garg <sumit.garg@xxxxxxxxxx>
Signed-off-by: Sumit Garg <sumit.garg@xxxxxxxxxx>
Co-developed-by: Pingfan Liu <kernelfans@xxxxxxxxx>
Signed-off-by: Pingfan Liu <kernelfans@xxxxxxxxx>
Signed-off-by: Lecopzer Chen <lecopzer.chen@xxxxxxxxxxxx>
Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Chen-Yu Tsai <wens@xxxxxxxx>
Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Cc: Colin Cross <ccross@xxxxxxxxxxx>
Cc: Daniel Thompson <daniel.thompson@xxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Guenter Roeck <groeck@xxxxxxxxxxxx>
Cc: Ian Rogers <irogers@xxxxxxxxxx>
Cc: Marc Zyngier <maz@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Masayoshi Mizuma <msys.mizuma@xxxxxxxxx>
Cc: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Nicholas Piggin <npiggin@xxxxxxxxx>
Cc: Petr Mladek <pmladek@xxxxxxxx>
Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Cc: "Ravi V. Shankar" <ravi.v.shankar@xxxxxxxxx>
Cc: Ricardo Neri <ricardo.neri@xxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Stephen Boyd <swboyd@xxxxxxxxxxxx>
Cc: Tzung-Bi Shih <tzungbi@xxxxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/arm64/Kconfig | 2 ++
arch/arm64/kernel/watchdog_hld.c | 12 ++++++++++++
drivers/perf/arm_pmu.c | 5 +++++
drivers/perf/arm_pmuv3.c | 12 ++++++++++--
include/linux/perf/arm_pmu.h | 2 ++
5 files changed, 31 insertions(+), 2 deletions(-)
--- a/arch/arm64/Kconfig~arm64-enable-perf-events-based-hard-lockup-detector
+++ a/arch/arm64/Kconfig
@@ -203,12 +203,14 @@ config ARM64
select HAVE_FUNCTION_ERROR_INJECTION
select HAVE_FUNCTION_GRAPH_TRACER
select HAVE_GCC_PLUGINS
+ select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
select HAVE_HW_BREAKPOINT if PERF_EVENTS
select HAVE_IOREMAP_PROT
select HAVE_IRQ_TIME_ACCOUNTING
select HAVE_KVM
select HAVE_NMI
select HAVE_PERF_EVENTS
+ select HAVE_PERF_EVENTS_NMI if ARM64_PSEUDO_NMI
select HAVE_PERF_REGS
select HAVE_PERF_USER_STACK_DUMP
select HAVE_PREEMPT_DYNAMIC_KEY
--- a/arch/arm64/kernel/watchdog_hld.c~arm64-enable-perf-events-based-hard-lockup-detector
+++ a/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 watchdo
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();
+}
--- a/drivers/perf/arm_pmu.c~arm64-enable-perf-events-based-hard-lockup-detector
+++ a/drivers/perf/arm_pmu.c
@@ -687,6 +687,11 @@ static int armpmu_get_cpu_irq(struct arm
return per_cpu(hw_events->irq, cpu);
}
+bool arm_pmu_irq_is_nmi(void)
+{
+ return has_nmi;
+}
+
/*
* PMU hardware loses all context when a CPU goes offline.
* When a CPU is hotplugged back in, since some hardware registers are
--- a/drivers/perf/arm_pmuv3.c~arm64-enable-perf-events-based-hard-lockup-detector
+++ a/drivers/perf/arm_pmuv3.c
@@ -22,6 +22,7 @@
#include <linux/platform_device.h>
#include <linux/sched_clock.h>
#include <linux/smp.h>
+#include <linux/nmi.h>
#include <asm/arm_pmuv3.h>
@@ -1348,10 +1349,17 @@ static struct platform_driver armv8_pmu_
static int __init armv8_pmu_driver_init(void)
{
+ int ret;
+
if (acpi_disabled)
- return platform_driver_register(&armv8_pmu_driver);
+ ret = platform_driver_register(&armv8_pmu_driver);
else
- return arm_pmu_acpi_probe(armv8_pmuv3_pmu_init);
+ ret = arm_pmu_acpi_probe(armv8_pmuv3_pmu_init);
+
+ if (!ret)
+ lockup_detector_retry_init();
+
+ return ret;
}
device_initcall(armv8_pmu_driver_init)
--- a/include/linux/perf/arm_pmu.h~arm64-enable-perf-events-based-hard-lockup-detector
+++ a/include/linux/perf/arm_pmu.h
@@ -171,6 +171,8 @@ void kvm_host_pmu_init(struct arm_pmu *p
#define kvm_host_pmu_init(x) do { } while(0)
#endif
+bool arm_pmu_irq_is_nmi(void);
+
/* Internal functions only for core arm_pmu code */
struct arm_pmu *armpmu_alloc(void);
void armpmu_free(struct arm_pmu *pmu);
_
Patches currently in -mm which might be from dianders@xxxxxxxxxxxx are
migrate_pages-avoid-blocking-for-io-in-migrate_sync_light.patch
watchdog-perf-define-dummy-watchdog_update_hrtimer_threshold-on-correct-config.patch
watchdog-perf-more-properly-prevent-false-positives-with-turbo-modes.patch
watchdog-hardlockup-add-comments-to-touch_nmi_watchdog.patch
watchdog-perf-rename-watchdog_hldc-to-watchdog_perfc.patch
watchdog-hardlockup-move-perf-hardlockup-checking-panic-to-common-watchdogc.patch
watchdog-hardlockup-style-changes-to-watchdog_hardlockup_check-is_hardlockup.patch
watchdog-hardlockup-add-a-cpu-param-to-watchdog_hardlockup_check.patch
watchdog-hardlockup-move-perf-hardlockup-watchdog-petting-to-watchdogc.patch
watchdog-hardlockup-rename-some-nmi-watchdog-constants-function.patch
watchdog-hardlockup-have-the-perf-hardlockup-use-__weak-functions-more-cleanly.patch
watchdog-hardlockup-detect-hard-lockups-using-secondary-buddy-cpus.patch
watchdog-perf-add-a-weak-function-for-an-arch-to-detect-if-perf-can-use-nmis.patch
arm64-enable-perf-events-based-hard-lockup-detector.patch
