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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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9a01c3ed5c
Patch series "improvements to the nmi_backtrace code" v9. This patch series modifies the trigger_xxx_backtrace() NMI-based remote backtracing code to make it more flexible, and makes a few small improvements along the way. The motivation comes from the task isolation code, where there are scenarios where we want to be able to diagnose a case where some cpu is about to interrupt a task-isolated cpu. It can be helpful to see both where the interrupting cpu is, and also an approximation of where the cpu that is being interrupted is. The nmi_backtrace framework allows us to discover the stack of the interrupted cpu. I've tested that the change works as desired on tile, and build-tested x86, arm, mips, and sparc64. For x86 I confirmed that the generic cpuidle stuff as well as the architecture-specific routines are in the new cpuidle section. For arm, mips, and sparc I just build-tested it and made sure the generic cpuidle routines were in the new cpuidle section, but I didn't attempt to figure out which the platform-specific idle routines might be. That might be more usefully done by someone with platform experience in follow-up patches. This patch (of 4): Currently you can only request a backtrace of either all cpus, or all cpus but yourself. It can also be helpful to request a remote backtrace of a single cpu, and since we want that, the logical extension is to support a cpumask as the underlying primitive. This change modifies the existing lib/nmi_backtrace.c code to take a cpumask as its basic primitive, and modifies the linux/nmi.h code to use the new "cpumask" method instead. The existing clients of nmi_backtrace (arm and x86) are converted to using the new cpumask approach in this change. The other users of the backtracing API (sparc64 and mips) are converted to use the cpumask approach rather than the all/allbutself approach. The mips code ignored the "include_self" boolean but with this change it will now also dump a local backtrace if requested. Link: http://lkml.kernel.org/r/1472487169-14923-2-git-send-email-cmetcalf@mellanox.com Signed-off-by: Chris Metcalf <cmetcalf@mellanox.com> Tested-by: Daniel Thompson <daniel.thompson@linaro.org> [arm] Reviewed-by: Aaron Tomlin <atomlin@redhat.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Russell King <linux@arm.linux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: David Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
126 lines
3.1 KiB
C
126 lines
3.1 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)
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#include <asm/nmi.h>
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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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#if defined(CONFIG_HARDLOCKUP_DETECTOR)
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extern void hardlockup_detector_disable(void);
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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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/*
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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, false);
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return true;
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}
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static inline bool trigger_allbutself_cpu_backtrace(void)
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{
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arch_trigger_cpumask_backtrace(cpu_online_mask, true);
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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, false);
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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), false);
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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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bool exclude_self,
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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_allbutself_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_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_LOCKUP_DETECTOR
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u64 hw_nmi_get_sample_period(int watchdog_thresh);
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extern int nmi_watchdog_enabled;
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extern int soft_watchdog_enabled;
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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_cpumask_bits;
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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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struct ctl_table;
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extern int proc_watchdog(struct ctl_table *, int ,
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void __user *, size_t *, loff_t *);
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extern int proc_nmi_watchdog(struct ctl_table *, int ,
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void __user *, size_t *, loff_t *);
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extern int proc_soft_watchdog(struct ctl_table *, int ,
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void __user *, size_t *, loff_t *);
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extern int proc_watchdog_thresh(struct ctl_table *, int ,
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void __user *, size_t *, loff_t *);
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extern int proc_watchdog_cpumask(struct ctl_table *, int,
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void __user *, size_t *, loff_t *);
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extern int lockup_detector_suspend(void);
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extern void lockup_detector_resume(void);
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#else
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static inline int lockup_detector_suspend(void)
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{
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return 0;
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}
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static inline void lockup_detector_resume(void)
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{
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}
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#endif
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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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#endif
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