mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-28 20:02:17 +00:00
8d539b84f1
The APIs that allow backtracing across CPUs have always had a way to exclude the current CPU. This convenience means callers didn't need to find a place to allocate a CPU mask just to handle the common case. Let's extend the API to take a CPU ID to exclude instead of just a boolean. This isn't any more complex for the API to handle and allows the hardlockup detector to exclude a different CPU (the one it already did a trace for) without needing to find space for a CPU mask. Arguably, this new API also encourages safer behavior. Specifically if the caller wants to avoid tracing the current CPU (maybe because they already traced the current CPU) this makes it more obvious to the caller that they need to make sure that the current CPU ID can't change. [akpm@linux-foundation.org: fix trigger_allbutcpu_cpu_backtrace() stub] Link: https://lkml.kernel.org/r/20230804065935.v4.1.Ia35521b91fc781368945161d7b28538f9996c182@changeid Signed-off-by: Douglas Anderson <dianders@chromium.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: kernel test robot <lkp@intel.com> Cc: Lecopzer Chen <lecopzer.chen@mediatek.com> Cc: Petr Mladek <pmladek@suse.com> Cc: Pingfan Liu <kernelfans@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
238 lines
7.7 KiB
C
238 lines
7.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* linux/include/linux/nmi.h
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*/
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#ifndef LINUX_NMI_H
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#define LINUX_NMI_H
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#include <linux/sched.h>
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#include <asm/irq.h>
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/* Arch specific watchdogs might need to share extra watchdog-related APIs. */
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#if defined(CONFIG_HARDLOCKUP_DETECTOR_ARCH) || defined(CONFIG_HARDLOCKUP_DETECTOR_SPARC64)
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#include <asm/nmi.h>
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#endif
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#ifdef CONFIG_LOCKUP_DETECTOR
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void lockup_detector_init(void);
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void lockup_detector_retry_init(void);
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void lockup_detector_soft_poweroff(void);
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void lockup_detector_cleanup(void);
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extern int watchdog_user_enabled;
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extern int watchdog_thresh;
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extern unsigned long watchdog_enabled;
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extern struct cpumask watchdog_cpumask;
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extern unsigned long *watchdog_cpumask_bits;
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#ifdef CONFIG_SMP
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extern int sysctl_softlockup_all_cpu_backtrace;
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extern int sysctl_hardlockup_all_cpu_backtrace;
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#else
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#define sysctl_softlockup_all_cpu_backtrace 0
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#define sysctl_hardlockup_all_cpu_backtrace 0
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#endif /* !CONFIG_SMP */
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#else /* CONFIG_LOCKUP_DETECTOR */
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static inline void lockup_detector_init(void) { }
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static inline void lockup_detector_retry_init(void) { }
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static inline void lockup_detector_soft_poweroff(void) { }
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static inline void lockup_detector_cleanup(void) { }
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#endif /* !CONFIG_LOCKUP_DETECTOR */
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#ifdef CONFIG_SOFTLOCKUP_DETECTOR
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extern void touch_softlockup_watchdog_sched(void);
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extern void touch_softlockup_watchdog(void);
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extern void touch_softlockup_watchdog_sync(void);
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extern void touch_all_softlockup_watchdogs(void);
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extern unsigned int softlockup_panic;
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extern int lockup_detector_online_cpu(unsigned int cpu);
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extern int lockup_detector_offline_cpu(unsigned int cpu);
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#else /* CONFIG_SOFTLOCKUP_DETECTOR */
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static inline void touch_softlockup_watchdog_sched(void) { }
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static inline void touch_softlockup_watchdog(void) { }
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static inline void touch_softlockup_watchdog_sync(void) { }
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static inline void touch_all_softlockup_watchdogs(void) { }
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#define lockup_detector_online_cpu NULL
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#define lockup_detector_offline_cpu NULL
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#endif /* CONFIG_SOFTLOCKUP_DETECTOR */
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#ifdef CONFIG_DETECT_HUNG_TASK
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void reset_hung_task_detector(void);
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#else
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static inline void reset_hung_task_detector(void) { }
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#endif
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/*
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* The run state of the lockup detectors is controlled by the content of the
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* 'watchdog_enabled' variable. Each lockup detector has its dedicated bit -
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* bit 0 for the hard lockup detector and bit 1 for the soft lockup detector.
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*
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* 'watchdog_user_enabled', 'watchdog_hardlockup_user_enabled' and
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* 'watchdog_softlockup_user_enabled' are variables that are only used as an
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* 'interface' between the parameters in /proc/sys/kernel and the internal
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* state bits in 'watchdog_enabled'. The 'watchdog_thresh' variable is
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* handled differently because its value is not boolean, and the lockup
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* detectors are 'suspended' while 'watchdog_thresh' is equal zero.
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*/
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#define WATCHDOG_HARDLOCKUP_ENABLED_BIT 0
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#define WATCHDOG_SOFTOCKUP_ENABLED_BIT 1
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#define WATCHDOG_HARDLOCKUP_ENABLED (1 << WATCHDOG_HARDLOCKUP_ENABLED_BIT)
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#define WATCHDOG_SOFTOCKUP_ENABLED (1 << WATCHDOG_SOFTOCKUP_ENABLED_BIT)
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#if defined(CONFIG_HARDLOCKUP_DETECTOR)
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extern void hardlockup_detector_disable(void);
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extern unsigned int hardlockup_panic;
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#else
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static inline void hardlockup_detector_disable(void) {}
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#endif
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/* Sparc64 has special implemetantion that is always enabled. */
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#if defined(CONFIG_HARDLOCKUP_DETECTOR) || defined(CONFIG_HARDLOCKUP_DETECTOR_SPARC64)
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void arch_touch_nmi_watchdog(void);
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#else
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static inline void arch_touch_nmi_watchdog(void) { }
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#endif
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#if defined(CONFIG_HARDLOCKUP_DETECTOR_COUNTS_HRTIMER)
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void watchdog_hardlockup_touch_cpu(unsigned int cpu);
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void watchdog_hardlockup_check(unsigned int cpu, struct pt_regs *regs);
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#endif
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#if defined(CONFIG_HARDLOCKUP_DETECTOR_PERF)
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extern void hardlockup_detector_perf_stop(void);
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extern void hardlockup_detector_perf_restart(void);
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extern void hardlockup_detector_perf_cleanup(void);
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#else
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static inline void hardlockup_detector_perf_stop(void) { }
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static inline void hardlockup_detector_perf_restart(void) { }
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static inline void hardlockup_detector_perf_cleanup(void) { }
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#endif
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void watchdog_hardlockup_stop(void);
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void watchdog_hardlockup_start(void);
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int watchdog_hardlockup_probe(void);
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void watchdog_hardlockup_enable(unsigned int cpu);
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void watchdog_hardlockup_disable(unsigned int cpu);
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void lockup_detector_reconfigure(void);
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#ifdef CONFIG_HARDLOCKUP_DETECTOR_BUDDY
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void watchdog_buddy_check_hardlockup(int hrtimer_interrupts);
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#else
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static inline void watchdog_buddy_check_hardlockup(int hrtimer_interrupts) {}
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#endif
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/**
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* touch_nmi_watchdog - manually reset the hardlockup watchdog timeout.
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*
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* If we support detecting hardlockups, touch_nmi_watchdog() may be
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* used to pet the watchdog (reset the timeout) - for code which
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* intentionally disables interrupts for a long time. This call is stateless.
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*
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* Though this function has "nmi" in the name, the hardlockup watchdog might
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* not be backed by NMIs. This function will likely be renamed to
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* touch_hardlockup_watchdog() in the future.
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*/
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static inline void touch_nmi_watchdog(void)
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{
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/*
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* Pass on to the hardlockup detector selected via CONFIG_. Note that
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* the hardlockup detector may not be arch-specific nor using NMIs
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* and the arch_touch_nmi_watchdog() function will likely be renamed
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* in the future.
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*/
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arch_touch_nmi_watchdog();
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touch_softlockup_watchdog();
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}
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/*
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* Create trigger_all_cpu_backtrace() out of the arch-provided
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* base function. Return whether such support was available,
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* to allow calling code to fall back to some other mechanism:
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*/
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#ifdef arch_trigger_cpumask_backtrace
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static inline bool trigger_all_cpu_backtrace(void)
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{
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arch_trigger_cpumask_backtrace(cpu_online_mask, -1);
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return true;
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}
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static inline bool trigger_allbutcpu_cpu_backtrace(int exclude_cpu)
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{
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arch_trigger_cpumask_backtrace(cpu_online_mask, exclude_cpu);
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return true;
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}
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static inline bool trigger_cpumask_backtrace(struct cpumask *mask)
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{
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arch_trigger_cpumask_backtrace(mask, -1);
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return true;
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}
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static inline bool trigger_single_cpu_backtrace(int cpu)
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{
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arch_trigger_cpumask_backtrace(cpumask_of(cpu), -1);
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return true;
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}
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/* generic implementation */
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void nmi_trigger_cpumask_backtrace(const cpumask_t *mask,
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int exclude_cpu,
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void (*raise)(cpumask_t *mask));
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bool nmi_cpu_backtrace(struct pt_regs *regs);
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#else
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static inline bool trigger_all_cpu_backtrace(void)
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{
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return false;
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}
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static inline bool trigger_allbutcpu_cpu_backtrace(int exclude_cpu)
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{
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return false;
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}
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static inline bool trigger_cpumask_backtrace(struct cpumask *mask)
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{
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return false;
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}
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static inline bool trigger_single_cpu_backtrace(int cpu)
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{
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return false;
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}
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#endif
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#ifdef CONFIG_HARDLOCKUP_DETECTOR_PERF
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u64 hw_nmi_get_sample_period(int watchdog_thresh);
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bool arch_perf_nmi_is_available(void);
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#endif
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#if defined(CONFIG_HARDLOCKUP_CHECK_TIMESTAMP) && \
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defined(CONFIG_HARDLOCKUP_DETECTOR_PERF)
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void watchdog_update_hrtimer_threshold(u64 period);
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#else
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static inline void watchdog_update_hrtimer_threshold(u64 period) { }
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#endif
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struct ctl_table;
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int proc_watchdog(struct ctl_table *, int, void *, size_t *, loff_t *);
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int proc_nmi_watchdog(struct ctl_table *, int , void *, size_t *, loff_t *);
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int proc_soft_watchdog(struct ctl_table *, int , void *, size_t *, loff_t *);
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int proc_watchdog_thresh(struct ctl_table *, int , void *, size_t *, loff_t *);
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int proc_watchdog_cpumask(struct ctl_table *, int, void *, size_t *, loff_t *);
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#ifdef CONFIG_HAVE_ACPI_APEI_NMI
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#include <asm/nmi.h>
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#endif
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#ifdef CONFIG_NMI_CHECK_CPU
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void nmi_backtrace_stall_snap(const struct cpumask *btp);
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void nmi_backtrace_stall_check(const struct cpumask *btp);
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#else
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static inline void nmi_backtrace_stall_snap(const struct cpumask *btp) {}
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static inline void nmi_backtrace_stall_check(const struct cpumask *btp) {}
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#endif
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#endif
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