linux-kernel - [PATCH 1/2] watchdog: refactor watchdog

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Message-Id: <20250827100959.83023-2-cuiyunhui@bytedance.com>
Date: Wed, 27 Aug 2025 18:09:58 +0800
From: Yunhui Cui <cuiyunhui@...edance.com>
To: paul.walmsley@...ive.com,
	palmer@...belt.com,
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Subject: [PATCH 1/2] watchdog: refactor watchdog_hld functionality

Move watchdog_hld.c to kernel/, and rename arm_pmu_irq_is_nmi()
to arch_pmu_irq_is_nmi() for cross-arch reusability.

Signed-off-by: Yunhui Cui <cuiyunhui@...edance.com>
---
 arch/arm64/kernel/Makefile                   | 1 -
 drivers/perf/arm_pmu.c                       | 2 +-
 include/linux/nmi.h                          | 1 +
 include/linux/perf/arm_pmu.h                 | 2 --
 kernel/Makefile                              | 2 +-
 {arch/arm64/kernel => kernel}/watchdog_hld.c | 8 ++++++--
 6 files changed, 9 insertions(+), 7 deletions(-)
 rename {arch/arm64/kernel => kernel}/watchdog_hld.c (97%)

diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 76f32e424065e..12d77f373fea4 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -44,7 +44,6 @@ obj-$(CONFIG_KUSER_HELPERS)		+= kuser32.o
 obj-$(CONFIG_FUNCTION_TRACER)		+= ftrace.o entry-ftrace.o
 obj-$(CONFIG_MODULES)			+= module.o module-plts.o
 obj-$(CONFIG_PERF_EVENTS)		+= perf_regs.o perf_callchain.o
-obj-$(CONFIG_HARDLOCKUP_DETECTOR_PERF)	+= watchdog_hld.o
 obj-$(CONFIG_HAVE_HW_BREAKPOINT)	+= hw_breakpoint.o
 obj-$(CONFIG_CPU_PM)			+= sleep.o suspend.o
 obj-$(CONFIG_KGDB)			+= kgdb.o
diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index 5c310e803dd78..4fd7f88d44543 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -696,7 +696,7 @@ static int armpmu_get_cpu_irq(struct arm_pmu *pmu, int cpu)
 	return per_cpu(hw_events->irq, cpu);
 }
 
-bool arm_pmu_irq_is_nmi(void)
+bool arch_pmu_irq_is_nmi(void)
 {
 	return has_nmi;
 }
diff --git a/include/linux/nmi.h b/include/linux/nmi.h
index cf3c6ab408aac..c34bdc4f43f6d 100644
--- a/include/linux/nmi.h
+++ b/include/linux/nmi.h
@@ -207,6 +207,7 @@ static inline bool trigger_single_cpu_backtrace(int cpu)
 #ifdef CONFIG_HARDLOCKUP_DETECTOR_PERF
 u64 hw_nmi_get_sample_period(int watchdog_thresh);
 bool arch_perf_nmi_is_available(void);
+bool arch_pmu_irq_is_nmi(void);
 #endif
 
 #if defined(CONFIG_HARDLOCKUP_CHECK_TIMESTAMP) && \
diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h
index 93c9a26492fcf..6b53fb453fd63 100644
--- a/include/linux/perf/arm_pmu.h
+++ b/include/linux/perf/arm_pmu.h
@@ -184,8 +184,6 @@ void kvm_host_pmu_init(struct arm_pmu *pmu);
 #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);
diff --git a/kernel/Makefile b/kernel/Makefile
index c60623448235f..4ec7702b00aa1 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -101,7 +101,7 @@ obj-$(CONFIG_KGDB) += debug/
 obj-$(CONFIG_DETECT_HUNG_TASK) += hung_task.o
 obj-$(CONFIG_LOCKUP_DETECTOR) += watchdog.o
 obj-$(CONFIG_HARDLOCKUP_DETECTOR_BUDDY) += watchdog_buddy.o
-obj-$(CONFIG_HARDLOCKUP_DETECTOR_PERF) += watchdog_perf.o
+obj-$(CONFIG_HARDLOCKUP_DETECTOR_PERF) += watchdog_perf.o watchdog_hld.o
 obj-$(CONFIG_SECCOMP) += seccomp.o
 obj-$(CONFIG_RELAY) += relay.o
 obj-$(CONFIG_SYSCTL) += utsname_sysctl.o
diff --git a/arch/arm64/kernel/watchdog_hld.c b/kernel/watchdog_hld.c
similarity index 97%
rename from arch/arm64/kernel/watchdog_hld.c
rename to kernel/watchdog_hld.c
index 3093037dcb7be..f3864e604a6b5 100644
--- a/arch/arm64/kernel/watchdog_hld.c
+++ b/kernel/watchdog_hld.c
@@ -1,7 +1,6 @@
 // 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
@@ -25,6 +24,11 @@ u64 hw_nmi_get_sample_period(int watchdog_thresh)
 	return (u64)max_cpu_freq * watchdog_thresh;
 }
 
+__weak bool arch_pmu_irq_is_nmi(void)
+{
+	return false;
+}
+
 bool __init arch_perf_nmi_is_available(void)
 {
 	/*
@@ -32,7 +36,7 @@ bool __init arch_perf_nmi_is_available(void)
 	 * 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();
+	return arch_pmu_irq_is_nmi();
 }
 
 static int watchdog_perf_update_period(void *data)
-- 
2.39.5