watchdog/hardlockup: move perf hardlockup watchdog petting to watchdog.c

In preparation for the buddy hardlockup detector, which wants the same
petting logic as the current perf hardlockup detector, move the code to
watchdog.c.  While doing this, rename the global variable to match others
nearby.  As part of this change we have to change the code to account for
the fact that the CPU we're running on might be different than the one
we're checking.

Currently the code in watchdog.c is guarded by
CONFIG_HARDLOCKUP_DETECTOR_PERF, which makes this change seem silly. 
However, a future patch will change this.

Link: https://lkml.kernel.org/r/20230519101840.v5.11.I00dfd6386ee00da25bf26d140559a41339b53e57@changeidSigned-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: Lecopzer Chen <lecopzer.chen@mediatek.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: Pingfan Liu <kernelfans@gmail.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: Sumit Garg <sumit.garg@linaro.org>
Cc: Tzung-Bi Shih <tzungbi@chromium.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

include/linux/nmi.h

@@ -88,7 +88,10 @@ static inline void hardlockup_detector_disable(void) {}
 #endif
 
 #if defined(CONFIG_HARDLOCKUP_DETECTOR_PERF)
+void arch_touch_nmi_watchdog(void);
 void watchdog_hardlockup_check(unsigned int cpu, struct pt_regs *regs);
+#elif !defined(CONFIG_HAVE_NMI_WATCHDOG)
+static inline void arch_touch_nmi_watchdog(void) { }
 #endif
 
 #if defined(CONFIG_HAVE_NMI_WATCHDOG) || defined(CONFIG_HARDLOCKUP_DETECTOR)
@@ -98,7 +101,6 @@ void watchdog_hardlockup_check(unsigned int cpu, struct pt_regs *regs);
 #endif
 
 #if defined(CONFIG_HARDLOCKUP_DETECTOR_PERF)
-extern void arch_touch_nmi_watchdog(void);
 extern void hardlockup_detector_perf_stop(void);
 extern void hardlockup_detector_perf_restart(void);
 extern void hardlockup_detector_perf_disable(void);
@@ -113,7 +115,6 @@ static inline void hardlockup_detector_perf_enable(void) { }
 static inline void hardlockup_detector_perf_cleanup(void) { }
 # if !defined(CONFIG_HAVE_NMI_WATCHDOG)
 static inline int hardlockup_detector_perf_init(void) { return -ENODEV; }
-static inline void arch_touch_nmi_watchdog(void) {}
 # else
 static inline int hardlockup_detector_perf_init(void) { return 0; }
 # endif

kernel/watchdog.c

@@ -90,8 +90,22 @@ __setup("nmi_watchdog=", hardlockup_panic_setup);
 static DEFINE_PER_CPU(atomic_t, hrtimer_interrupts);
 static DEFINE_PER_CPU(int, hrtimer_interrupts_saved);
 static DEFINE_PER_CPU(bool, watchdog_hardlockup_warned);
+static DEFINE_PER_CPU(bool, watchdog_hardlockup_touched);
 static unsigned long watchdog_hardlockup_all_cpu_dumped;
 
+notrace void arch_touch_nmi_watchdog(void)
+{
+	/*
+	 * Using __raw here because some code paths have
+	 * preemption enabled.  If preemption is enabled
+	 * then interrupts should be enabled too, in which
+	 * case we shouldn't have to worry about the watchdog
+	 * going off.
+	 */
+	raw_cpu_write(watchdog_hardlockup_touched, true);
+}
+EXPORT_SYMBOL(arch_touch_nmi_watchdog);
+
 static bool is_hardlockup(unsigned int cpu)
 {
 	int hrint = atomic_read(&per_cpu(hrtimer_interrupts, cpu));
@@ -116,6 +130,11 @@ static void watchdog_hardlockup_kick(void)
 
 void watchdog_hardlockup_check(unsigned int cpu, struct pt_regs *regs)
 {
+	if (per_cpu(watchdog_hardlockup_touched, cpu)) {
+		per_cpu(watchdog_hardlockup_touched, cpu) = false;
+		return;
+	}
+
 	/*
 	 * Check for a hardlockup by making sure the CPU's timer
 	 * interrupt is incrementing. The timer interrupt should have

kernel/watchdog_perf.c

@@ -20,26 +20,12 @@
 #include <asm/irq_regs.h>
 #include <linux/perf_event.h>
 
-static DEFINE_PER_CPU(bool, watchdog_nmi_touch);
 static DEFINE_PER_CPU(struct perf_event *, watchdog_ev);
 static DEFINE_PER_CPU(struct perf_event *, dead_event);
 static struct cpumask dead_events_mask;
 
 static atomic_t watchdog_cpus = ATOMIC_INIT(0);
 
-notrace void arch_touch_nmi_watchdog(void)
-{
-	/*
-	 * Using __raw here because some code paths have
-	 * preemption enabled.  If preemption is enabled
-	 * then interrupts should be enabled too, in which
-	 * case we shouldn't have to worry about the watchdog
-	 * going off.
-	 */
-	raw_cpu_write(watchdog_nmi_touch, true);
-}
-EXPORT_SYMBOL(arch_touch_nmi_watchdog);
-
 #ifdef CONFIG_HARDLOCKUP_CHECK_TIMESTAMP
 static DEFINE_PER_CPU(ktime_t, last_timestamp);
 static DEFINE_PER_CPU(unsigned int, nmi_rearmed);
@@ -115,11 +101,6 @@ static void watchdog_overflow_callback(struct perf_event *event,
 	if (!watchdog_check_timestamp())
 		return;
 
-	if (__this_cpu_read(watchdog_nmi_touch) == true) {
-		__this_cpu_write(watchdog_nmi_touch, false);
-		return;
-	}
-
 	watchdog_hardlockup_check(smp_processor_id(), regs);
 }