Messages in this thread Patch in this message | | | From | Ricardo Neri <> | Subject | [RFC PATCH v5 14/16] x86/watchdog: Add a shim hardlockup detector | Date | Tue, 4 May 2021 12:05:24 -0700 |
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The generic hardlockup detector is based on perf. It also provides a set of weak stubs that CPU architectures can override. Add a shim hardlockup detector for x86 that selects between perf and hpet implementations.
Specifically, this shim implementation is needed for the HPET-based hardlockup detector; it can also be used for future implementations.
Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ashok Raj <ashok.raj@intel.com> Cc: Andi Kleen <andi.kleen@intel.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: x86@kernel.org Suggested-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> --- Changes since v4: * Use a switch to enable and disable the various available detectors. (Andi)
Changes since v3: * Fixed style in multi-line comment. (Randy Dunlap)
Changes since v2: * Pass cpu number as argument to hardlockup_detector_[enable|disable]. (Thomas Gleixner)
Changes since v1: * Introduced this patch: Added an x86-specific shim hardlockup detector. (Nicholas Piggin) --- arch/x86/Kconfig.debug | 4 ++ arch/x86/kernel/Makefile | 1 + arch/x86/kernel/watchdog_hld.c | 80 ++++++++++++++++++++++++++++++++++ 3 files changed, 85 insertions(+) create mode 100644 arch/x86/kernel/watchdog_hld.c
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug index 0731da557a6d..4cdac3f80e80 100644 --- a/arch/x86/Kconfig.debug +++ b/arch/x86/Kconfig.debug @@ -117,9 +117,13 @@ config IOMMU_LEAK config HAVE_MMIOTRACE_SUPPORT def_bool y +config X86_HARDLOCKUP_DETECTOR + bool + config X86_HARDLOCKUP_DETECTOR_HPET bool "HPET Timer for Hard Lockup Detection" select HARDLOCKUP_DETECTOR_CORE + select X86_HARDLOCKUP_DETECTOR depends on HARDLOCKUP_DETECTOR && HPET_TIMER && HPET && (X86_64 || X86_32) help The hardlockup detector is driven by one counter of the Performance diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index 5d1a90b23577..3303f10b3d0a 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -115,6 +115,7 @@ obj-$(CONFIG_VM86) += vm86_32.o obj-$(CONFIG_EARLY_PRINTK) += early_printk.o obj-$(CONFIG_HPET_TIMER) += hpet.o +obj-$(CONFIG_X86_HARDLOCKUP_DETECTOR) += watchdog_hld.o obj-$(CONFIG_X86_HARDLOCKUP_DETECTOR_HPET) += watchdog_hld_hpet.o obj-$(CONFIG_AMD_NB) += amd_nb.o diff --git a/arch/x86/kernel/watchdog_hld.c b/arch/x86/kernel/watchdog_hld.c new file mode 100644 index 000000000000..8947a7644421 --- /dev/null +++ b/arch/x86/kernel/watchdog_hld.c @@ -0,0 +1,80 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * A shim hardlockup detector. It overrides the weak stubs of the generic + * implementation to select between the perf- or the hpet-based implementation. + * + * Copyright (C) Intel Corporation 2021 + */ + +#include <linux/nmi.h> +#include <asm/hpet.h> + +enum x86_hardlockup_detector { + X86_HARDLOCKUP_DETECTOR_PERF, + X86_HARDLOCKUP_DETECTOR_HPET, +}; + +static enum __read_mostly x86_hardlockup_detector detector_type; + +int watchdog_nmi_enable(unsigned int cpu) +{ + int ret = 0; + + switch (detector_type) { + case X86_HARDLOCKUP_DETECTOR_PERF: + hardlockup_detector_perf_enable(); + break; + case X86_HARDLOCKUP_DETECTOR_HPET: + hardlockup_detector_hpet_enable(cpu); + break; + default: + ret = -ENODEV; + } + + return ret; +} + +void watchdog_nmi_disable(unsigned int cpu) +{ + switch (detector_type) { + case X86_HARDLOCKUP_DETECTOR_PERF: + hardlockup_detector_perf_disable(); + break; + case X86_HARDLOCKUP_DETECTOR_HPET: + hardlockup_detector_hpet_disable(cpu); + break; + } +} + +int __init watchdog_nmi_probe(void) +{ + int ret; + + /* + * Try first with the HPET hardlockup detector. It will only + * succeed if selected at build time and the nmi_watchdog + * command-line parameter is configured. This ensure that the + * perf-based detector is used by default, if selected at + * build time. + */ + ret = hardlockup_detector_hpet_init(); + if (!ret) { + detector_type = X86_HARDLOCKUP_DETECTOR_HPET; + return ret; + } + + ret = hardlockup_detector_perf_init(); + if (!ret) { + detector_type = X86_HARDLOCKUP_DETECTOR_PERF; + return ret; + } + + return ret; +} + +void watchdog_nmi_stop(void) +{ + /* Only the HPET lockup detector defines a stop function. */ + if (detector_type == X86_HARDLOCKUP_DETECTOR_HPET) + hardlockup_detector_hpet_stop(); +} -- 2.17.1
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