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fee519389c
Emulate NMIs on systems where they are not available by using timer interrupts on other cpus. Each cpu will use its softlockup hrtimer to check that the next cpu is processing hrtimer interrupts by verifying that a counter is increasing. This patch is useful on systems where the hardlockup detector is not available due to a lack of NMIs, for example most ARM SoCs. Without this patch any cpu stuck with interrupts disabled can cause a hardware watchdog reset with no debugging information, but with this patch the kernel can detect the lockup and panic, which can result in useful debugging info. Signed-off-by: Colin Cross <ccross@android.com>
60 lines
1.4 KiB
C
60 lines
1.4 KiB
C
/*
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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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/**
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* touch_nmi_watchdog - restart NMI watchdog timeout.
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*
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* If the architecture supports the NMI watchdog, touch_nmi_watchdog()
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* may be used to reset the timeout - for code which intentionally
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* disables interrupts for a long time. This call is stateless.
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*/
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#if defined(CONFIG_HAVE_NMI_WATCHDOG) || defined(CONFIG_HARDLOCKUP_DETECTOR_NMI)
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#include <asm/nmi.h>
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#endif
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#if defined(CONFIG_HAVE_NMI_WATCHDOG) || defined(CONFIG_HARDLOCKUP_DETECTOR)
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extern void touch_nmi_watchdog(void);
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#else
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static inline void touch_nmi_watchdog(void)
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{
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touch_softlockup_watchdog();
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}
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#endif
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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_all_cpu_backtrace
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static inline bool trigger_all_cpu_backtrace(void)
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{
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arch_trigger_all_cpu_backtrace();
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return true;
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}
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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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#endif
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#ifdef CONFIG_LOCKUP_DETECTOR
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int hw_nmi_is_cpu_stuck(struct pt_regs *);
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u64 hw_nmi_get_sample_period(int watchdog_thresh);
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extern int watchdog_enabled;
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extern int watchdog_thresh;
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struct ctl_table;
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extern int proc_dowatchdog(struct ctl_table *, int ,
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void __user *, size_t *, loff_t *);
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#endif
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#endif
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