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" <[email protected]> Cc: Ashok Raj <[email protected]> Cc: Andi Kleen <[email protected]> Cc: Tony Luck <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Clemens Ladisch <[email protected]> Cc: Arnd Bergmann <[email protected]> Cc: Philippe Ombredanne <[email protected]> Cc: Kate Stewart <[email protected]> Cc: "Rafael J. Wysocki" <[email protected]> Cc: Mimi Zohar <[email protected]> Cc: Jan Kiszka <[email protected]> Cc: Nick Desaulniers <[email protected]> Cc: Masahiro Yamada <[email protected]> Cc: Nayna Jain <[email protected]> Cc: "Ravi V. Shankar" <[email protected]> Cc: [email protected] Suggested-by: Nicholas Piggin <[email protected]> Signed-off-by: Ricardo Neri <[email protected]> --- arch/x86/Kconfig.debug | 4 ++ arch/x86/kernel/Makefile | 1 + arch/x86/kernel/watchdog_hld.c | 78 ++++++++++++++++++++++++++++++++++ 3 files changed, 83 insertions(+) create mode 100644 arch/x86/kernel/watchdog_hld.c diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug index 3a2845a29e8a..5e5f4d2330af 100644 --- a/arch/x86/Kconfig.debug +++ b/arch/x86/Kconfig.debug @@ -169,10 +169,14 @@ config IOMMU_LEAK config HAVE_MMIOTRACE_SUPPORT def_bool y +config X86_HARDLOCKUP_DETECTOR + bool + config X86_HARDLOCKUP_DETECTOR_HPET bool "Use HPET Timer for Hard Lockup Detection" select SOFTLOCKUP_DETECTOR select HARDLOCKUP_DETECTOR + select X86_HARDLOCKUP_DETECTOR depends on HPET_TIMER && HPET && X86_64 help Say y to enable a hardlockup detector that is driven by an High- diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index 9d610e8a9224..5372453fe2a7 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -106,6 +106,7 @@ 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_APB_TIMER) += apb_timer.o diff --git a/arch/x86/kernel/watchdog_hld.c b/arch/x86/kernel/watchdog_hld.c new file mode 100644 index 000000000000..a2f6190dbce0 --- /dev/null +++ b/arch/x86/kernel/watchdog_hld.c @@ -0,0 +1,78 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * A shim hardlockup detector. It simply overrides the weak stubs of the + * generic implementation. + * + * Copyright (C) Intel Corporation 2019 + */ + +#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) +{ + if (detector_type == X86_HARDLOCKUP_DETECTOR_PERF) { + hardlockup_detector_perf_enable(); + return 0; + } + + if (detector_type == X86_HARDLOCKUP_DETECTOR_HPET) { + hardlockup_detector_hpet_enable(); + return 0; + } + + return -ENODEV; +} + +void watchdog_nmi_disable(unsigned int cpu) +{ + if (detector_type == X86_HARDLOCKUP_DETECTOR_PERF) { + hardlockup_detector_perf_disable(); + return; + } + + if (detector_type == X86_HARDLOCKUP_DETECTOR_HPET) { + hardlockup_detector_hpet_disable(); + return; + } +} + +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_enable(); +} -- 2.17.1
