From: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
To: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>, Borislav Petkov <bp@suse.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Jan Kiszka <jan.kiszka@siemens.com>,
Clemens Ladisch <clemens@ladisch.de>,
Ricardo Neri <ricardo.neri@intel.com>,
Stephane Eranian <eranian@google.com>,
Masahiro Yamada <yamada.masahiro@socionext.com>,
"H. Peter Anvin" <hpa@zytor.com>, Ashok Raj <ashok.raj@intel.com>,
x86@kernel.org, Andi Kleen <andi.kleen@intel.com>,
"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
Arnd Bergmann <arnd@arndb.de>,
Ricardo Neri <ricardo.neri-calderon@linux.intel.com>,
Mimi Zohar <zohar@linux.ibm.com>, Tony Luck <tony.luck@intel.com>,
Randy Dunlap <rdunlap@infradead.org>,
Nick Desaulniers <ndesaulniers@google.com>,
linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
Philippe Ombredanne <pombredanne@nexb.com>,
Nayna Jain <nayna@linux.ibm.com>
Subject: [RFC PATCH v4 15/21] watchdog/hardlockup/hpet: Only enable the HPET watchdog via a boot parameter
Date: Thu, 23 May 2019 18:16:17 -0700 [thread overview]
Message-ID: <1558660583-28561-16-git-send-email-ricardo.neri-calderon@linux.intel.com> (raw)
In-Reply-To: <1558660583-28561-1-git-send-email-ricardo.neri-calderon@linux.intel.com>
Keep the HPET-based hardlockup detector disabled unless explicitly enabled
via a command-line argument. If such parameter is not given, the
initialization of the hpet-based hardlockup detector fails and the NMI
watchdog will fallback to use the perf-based implementation.
Given that __setup("nmi_watchdog=") is already used to control the behavior
of the NMI watchdog (via hardlockup_panic_setup()), it cannot be used to
control of the hpet-based implementation. Instead, use a new
early_param("nmi_watchdog").
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: Clemens Ladisch <clemens@ladisch.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Cc: Mimi Zohar <zohar@linux.ibm.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Nayna Jain <nayna@linux.ibm.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com>
Cc: x86@kernel.org
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
--
checkpatch gives the following warning:
CHECK: __setup appears un-documented -- check Documentation/admin-guide/kernel-parameters.rst
+__setup("nmi_watchdog=", hardlockup_detector_hpet_setup);
This is a false-positive as the option nmi_watchdog is already
documented. The option is re-evaluated in this file as well.
---
.../admin-guide/kernel-parameters.txt | 8 ++++++-
arch/x86/kernel/watchdog_hld_hpet.c | 22 +++++++++++++++++++
2 files changed, 29 insertions(+), 1 deletion(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 138f6664b2e2..17ed3dcda13e 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2831,7 +2831,7 @@
Format: [state][,regs][,debounce][,die]
nmi_watchdog= [KNL,BUGS=X86] Debugging features for SMP kernels
- Format: [panic,][nopanic,][num]
+ Format: [panic,][nopanic,][num,][hpet]
Valid num: 0 or 1
0 - turn hardlockup detector in nmi_watchdog off
1 - turn hardlockup detector in nmi_watchdog on
@@ -2841,6 +2841,12 @@
please see 'nowatchdog'.
This is useful when you use a panic=... timeout and
need the box quickly up again.
+ When hpet is specified, the NMI watchdog will be driven
+ by an HPET timer, if available in the system. Otherwise,
+ it falls back to the default implementation (perf or
+ architecture-specific). Specifying hpet has no effect
+ if the NMI watchdog is not enabled (either at build time
+ or via the command line).
These settings can be accessed at runtime via
the nmi_watchdog and hardlockup_panic sysctls.
diff --git a/arch/x86/kernel/watchdog_hld_hpet.c b/arch/x86/kernel/watchdog_hld_hpet.c
index dcc50cd29374..76eed714a1cb 100644
--- a/arch/x86/kernel/watchdog_hld_hpet.c
+++ b/arch/x86/kernel/watchdog_hld_hpet.c
@@ -351,6 +351,28 @@ void hardlockup_detector_hpet_stop(void)
disable_timer(hld_data);
}
+/**
+ * hardlockup_detector_hpet_setup() - Parse command-line parameters
+ * @str: A string containing the kernel command line
+ *
+ * Parse the nmi_watchdog parameter from the kernel command line. If
+ * selected by the user, use this implementation to detect hardlockups.
+ */
+static int __init hardlockup_detector_hpet_setup(char *str)
+{
+ if (!str)
+ return -EINVAL;
+
+ if (parse_option_str(str, "hpet"))
+ hardlockup_use_hpet = true;
+
+ if (!nmi_watchdog_user_enabled && hardlockup_use_hpet)
+ pr_warn("Selecting HPET NMI watchdog has no effect with NMI watchdog disabled\n");
+
+ return 0;
+}
+early_param("nmi_watchdog", hardlockup_detector_hpet_setup);
+
/**
* hardlockup_detector_hpet_init() - Initialize the hardlockup detector
*
--
2.17.1
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next prev parent reply other threads:[~2019-05-24 1:18 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-24 1:16 [RFC PATCH v4 00/21] Implement an HPET-based hardlockup detector Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 01/21] x86/msi: Add definition for NMI delivery mode Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 02/21] x86/hpet: Expose hpet_writel() in header Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 03/21] x86/hpet: Calculate ticks-per-second in a separate function Ricardo Neri
2019-06-14 15:54 ` Thomas Gleixner
2019-06-14 15:59 ` Thomas Gleixner
2019-06-18 22:48 ` Ricardo Neri
2019-06-18 23:13 ` Thomas Gleixner
2019-05-24 1:16 ` [RFC PATCH v4 04/21] x86/hpet: Add hpet_set_comparator() for periodic and one-shot modes Ricardo Neri
2019-06-14 18:17 ` Thomas Gleixner
2019-06-18 22:48 ` Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 05/21] x86/hpet: Reserve timer for the HPET hardlockup detector Ricardo Neri
2019-06-11 19:54 ` Thomas Gleixner
2019-06-14 1:14 ` Ricardo Neri
2019-06-14 16:10 ` Thomas Gleixner
2019-06-18 22:48 ` Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 06/21] x86/hpet: Configure the timer used by the " Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 07/21] watchdog/hardlockup: Define a generic function to detect hardlockups Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 08/21] watchdog/hardlockup: Decouple the hardlockup detector from perf Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 09/21] x86/nmi: Add a NMI_WATCHDOG NMI handler category Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 10/21] watchdog/hardlockup: Add function to enable NMI watchdog on all allowed CPUs at once Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 11/21] x86/watchdog/hardlockup: Add an HPET-based hardlockup detector Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 12/21] watchdog/hardlockup/hpet: Adjust timer expiration on the number of monitored CPUs Ricardo Neri
2019-06-11 20:11 ` Thomas Gleixner
2019-06-18 22:46 ` Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 13/21] x86/watchdog/hardlockup/hpet: Determine if HPET timer caused NMI Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 14/21] watchdog/hardlockup: Use parse_option_str() to handle "nmi_watchdog" Ricardo Neri
2019-05-24 1:16 ` Ricardo Neri [this message]
2019-05-24 1:16 ` [RFC PATCH v4 16/21] x86/watchdog: Add a shim hardlockup detector Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 17/21] x86/tsc: Switch to perf-based hardlockup detector if TSC become unstable Ricardo Neri
2019-06-07 0:35 ` Stephane Eranian via iommu
2019-06-07 14:14 ` Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 18/21] x86/apic: Add a parameter for the APIC delivery mode Ricardo Neri
2019-06-16 9:55 ` Thomas Gleixner
2019-06-18 22:47 ` Ricardo Neri
2019-06-18 23:15 ` Thomas Gleixner
2019-05-24 1:16 ` [RFC PATCH v4 19/21] iommu/vt-d: Rework prepare_irte() to support per-irq " Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 20/21] iommu/vt-d: hpet: Reserve an interrupt remampping table entry for watchdog Ricardo Neri
2019-06-16 18:42 ` Thomas Gleixner
2019-06-16 19:21 ` Thomas Gleixner
2019-06-17 8:25 ` Thomas Gleixner
2019-06-17 21:38 ` Stephane Eranian via iommu
2019-06-17 23:08 ` Thomas Gleixner
2019-06-19 15:43 ` Jacob Pan
2019-06-21 15:33 ` Thomas Gleixner
2019-06-21 17:31 ` Jacob Pan
2019-06-21 18:39 ` Jacob Pan
2019-06-21 20:05 ` Thomas Gleixner
2019-06-21 23:55 ` Ricardo Neri
2019-06-22 7:21 ` Thomas Gleixner
2019-10-18 2:48 ` Ricardo Neri
2019-06-18 22:45 ` Ricardo Neri
2019-05-24 1:16 ` [RFC PATCH v4 21/21] x86/watchdog/hardlockup/hpet: Support interrupt remapping Ricardo Neri
2019-06-16 8:44 ` Thomas Gleixner
2019-06-16 8:53 ` Thomas Gleixner
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