diff mbox series

[PATCHv3,4/4] arm64: Enable perf events based hard lockup detector

Message ID 20211014024155.15253-5-kernelfans@gmail.com (mailing list archive)
State New, archived
Headers show
Series watchdog_hld cleanup and async model for arm64 | expand

Commit Message

Pingfan Liu Oct. 14, 2021, 2:41 a.m. UTC 
From: Sumit Garg <sumit.garg@linaro.org>

With the recent feature added to enable perf events to use pseudo NMIs
as interrupts on platforms which support GICv3 or later, its now been
possible to enable hard lockup detector (or NMI watchdog) on arm64
platforms. So enable corresponding support.

One thing to note here is that normally lockup detector is initialized
just after the early initcalls but PMU on arm64 comes up much later as
device_initcall(). To cope with that, overriding watchdog_nmi_probe() to
let the watchdog framework know PMU not ready, and inform the framework
to re-initialize lockup detection once PMU has been initialized.

[1]: http://lore.kernel.org/linux-arm-kernel/1610712101-14929-1-git-send-email-sumit.garg@linaro.org

Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
(Pingfan: adapt it to watchdog_hld async model based on [1])
Co-developed-by: Pingfan Liu <kernelfans@gmail.com>
Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
Cc: Sumit Garg <sumit.garg@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Wang Qing <wangqing@vivo.com>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Santosh Sivaraj <santosh@fossix.org>
Cc: linux-kernel@vger.kernel.org
To: linux-arm-kernel@lists.infradead.org
---
 arch/arm64/Kconfig               |  2 ++
 arch/arm64/kernel/Makefile       |  1 +
 arch/arm64/kernel/perf_event.c   | 11 ++++++++--
 arch/arm64/kernel/watchdog_hld.c | 36 ++++++++++++++++++++++++++++++++
 drivers/perf/arm_pmu.c           |  5 +++++
 include/linux/perf/arm_pmu.h     |  2 ++
 6 files changed, 55 insertions(+), 2 deletions(-)
 create mode 100644 arch/arm64/kernel/watchdog_hld.c

Comments

kernel test robot Oct. 26, 2021, 5:10 a.m. UTC | #1 
Hi Pingfan,

I love your patch! Yet something to improve:

[auto build test ERROR on soc/for-next]
[also build test ERROR on kvmarm/next linus/master v5.15-rc7]
[cannot apply to arm64/for-next/core arm/for-next xilinx-xlnx/master]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Pingfan-Liu/watchdog_hld-cleanup-and-async-model-for-arm64/20211014-104443
base:   https://git.kernel.org/pub/scm/linux/kernel/git/soc/soc.git for-next
config: arm64-randconfig-p001-20211016 (attached as .config)
compiler: aarch64-linux-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/4c319c41e49036be58068395965bd33a5de02396
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Pingfan-Liu/watchdog_hld-cleanup-and-async-model-for-arm64/20211014-104443
        git checkout 4c319c41e49036be58068395965bd33a5de02396
        # save the attached .config to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=arm64 SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   aarch64-linux-ld: arch/arm64/kernel/perf_event.o: in function `armv8_pmu_driver_init':
>> perf_event.c:(.init.text+0x20): undefined reference to `detector_delay_init_state'
   aarch64-linux-ld: arch/arm64/kernel/perf_event.o: relocation R_AARCH64_ADR_PREL_PG_HI21 against symbol `detector_delay_init_state' which may bind externally can not be used when making a shared object; recompile with -fPIC
   perf_event.c:(.init.text+0x20): dangerous relocation: unsupported relocation
>> aarch64-linux-ld: perf_event.c:(.init.text+0x30): undefined reference to `detector_delay_init_state'
>> aarch64-linux-ld: perf_event.c:(.init.text+0x34): undefined reference to `hld_detector_wait'
   aarch64-linux-ld: arch/arm64/kernel/perf_event.o: relocation R_AARCH64_ADR_PREL_PG_HI21 against symbol `hld_detector_wait' which may bind externally can not be used when making a shared object; recompile with -fPIC
   perf_event.c:(.init.text+0x34): dangerous relocation: unsupported relocation
   aarch64-linux-ld: perf_event.c:(.init.text+0x3c): undefined reference to `hld_detector_wait'

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
kernel test robot Oct. 26, 2021, 10:20 a.m. UTC | #2 
Hi Pingfan,

I love your patch! Yet something to improve:

[auto build test ERROR on soc/for-next]
[also build test ERROR on kvmarm/next linus/master v5.15-rc7 next-20211025]
[cannot apply to arm64/for-next/core arm/for-next xilinx-xlnx/master]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Pingfan-Liu/watchdog_hld-cleanup-and-async-model-for-arm64/20211014-104443
base:   https://git.kernel.org/pub/scm/linux/kernel/git/soc/soc.git for-next
config: arm64-randconfig-r012-20211025 (attached as .config)
compiler: aarch64-linux-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/4c319c41e49036be58068395965bd33a5de02396
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Pingfan-Liu/watchdog_hld-cleanup-and-async-model-for-arm64/20211014-104443
        git checkout 4c319c41e49036be58068395965bd33a5de02396
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=arm64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   arch/arm64/kernel/watchdog_hld.c: In function 'watchdog_nmi_probe':
>> arch/arm64/kernel/watchdog_hld.c:32:19: error: implicit declaration of function 'arm_pmu_irq_is_nmi' [-Werror=implicit-function-declaration]
      32 |         else if (!arm_pmu_irq_is_nmi())
         |                   ^~~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors


vim +/arm_pmu_irq_is_nmi +32 arch/arm64/kernel/watchdog_hld.c

    27	
    28	int __init watchdog_nmi_probe(void)
    29	{
    30		if (detector_delay_init_state != DELAY_INIT_READY)
    31			return -EBUSY;
  > 32		else if (!arm_pmu_irq_is_nmi())

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
diff mbox series

Patch

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index fee914c716aa..762500f27aec 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -189,6 +189,8 @@  config ARM64
 	select HAVE_NMI
 	select HAVE_PATA_PLATFORM
 	select HAVE_PERF_EVENTS
+	select HAVE_PERF_EVENTS_NMI if ARM64_PSEUDO_NMI
+	select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
 	select HAVE_PERF_REGS
 	select HAVE_PERF_USER_STACK_DUMP
 	select HAVE_REGS_AND_STACK_ACCESS_API
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 3f1490bfb938..789c2fe5bb90 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -46,6 +46,7 @@  obj-$(CONFIG_MODULES)			+= module.o
 obj-$(CONFIG_ARM64_MODULE_PLTS)		+= module-plts.o
 obj-$(CONFIG_PERF_EVENTS)		+= perf_regs.o perf_callchain.o
 obj-$(CONFIG_HW_PERF_EVENTS)		+= perf_event.o
+obj-$(CONFIG_HARDLOCKUP_DETECTOR_PERF)	+= watchdog_hld.o
 obj-$(CONFIG_HAVE_HW_BREAKPOINT)	+= hw_breakpoint.o
 obj-$(CONFIG_CPU_PM)			+= sleep.o suspend.o
 obj-$(CONFIG_CPU_IDLE)			+= cpuidle.o
diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index b4044469527e..8e4c39f1db52 100644
--- a/arch/arm64/kernel/perf_event.c
+++ b/arch/arm64/kernel/perf_event.c
@@ -23,6 +23,7 @@ 
 #include <linux/platform_device.h>
 #include <linux/sched_clock.h>
 #include <linux/smp.h>
+#include <linux/nmi.h>
 
 /* ARMv8 Cortex-A53 specific event types. */
 #define ARMV8_A53_PERFCTR_PREF_LINEFILL				0xC2
@@ -1284,10 +1285,16 @@  static struct platform_driver armv8_pmu_driver = {
 
 static int __init armv8_pmu_driver_init(void)
 {
+	int ret;
+
 	if (acpi_disabled)
-		return platform_driver_register(&armv8_pmu_driver);
+		ret = platform_driver_register(&armv8_pmu_driver);
 	else
-		return arm_pmu_acpi_probe(armv8_pmuv3_init);
+		ret = arm_pmu_acpi_probe(armv8_pmuv3_init);
+
+	detector_delay_init_state = DELAY_INIT_READY;
+	wake_up(&hld_detector_wait);
+	return ret;
 }
 device_initcall(armv8_pmu_driver_init)
 
diff --git a/arch/arm64/kernel/watchdog_hld.c b/arch/arm64/kernel/watchdog_hld.c
new file mode 100644
index 000000000000..85536906a186
--- /dev/null
+++ b/arch/arm64/kernel/watchdog_hld.c
@@ -0,0 +1,36 @@ 
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/nmi.h>
+#include <linux/cpufreq.h>
+#include <linux/perf/arm_pmu.h>
+
+/*
+ * Safe maximum CPU frequency in case a particular platform doesn't implement
+ * cpufreq driver. Although, architecture doesn't put any restrictions on
+ * maximum frequency but 5 GHz seems to be safe maximum given the available
+ * Arm CPUs in the market which are clocked much less than 5 GHz. On the other
+ * hand, we can't make it much higher as it would lead to a large hard-lockup
+ * detection timeout on parts which are running slower (eg. 1GHz on
+ * Developerbox) and doesn't possess a cpufreq driver.
+ */
+#define SAFE_MAX_CPU_FREQ	5000000000UL // 5 GHz
+u64 hw_nmi_get_sample_period(int watchdog_thresh)
+{
+	unsigned int cpu = smp_processor_id();
+	unsigned long max_cpu_freq;
+
+	max_cpu_freq = cpufreq_get_hw_max_freq(cpu) * 1000UL;
+	if (!max_cpu_freq)
+		max_cpu_freq = SAFE_MAX_CPU_FREQ;
+
+	return (u64)max_cpu_freq * watchdog_thresh;
+}
+
+int __init watchdog_nmi_probe(void)
+{
+	if (detector_delay_init_state != DELAY_INIT_READY)
+		return -EBUSY;
+	else if (!arm_pmu_irq_is_nmi())
+		return -ENODEV;
+
+	return hardlockup_detector_perf_init();
+}
diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index 295cc7952d0e..e77f4897fca2 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -697,6 +697,11 @@  static int armpmu_get_cpu_irq(struct arm_pmu *pmu, int cpu)
 	return per_cpu(hw_events->irq, cpu);
 }
 
+bool arm_pmu_irq_is_nmi(void)
+{
+	return has_nmi;
+}
+
 /*
  * PMU hardware loses all context when a CPU goes offline.
  * When a CPU is hotplugged back in, since some hardware registers are
diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h
index 2512e2f9cd4e..9325d01adc3e 100644
--- a/include/linux/perf/arm_pmu.h
+++ b/include/linux/perf/arm_pmu.h
@@ -169,6 +169,8 @@  void kvm_host_pmu_init(struct arm_pmu *pmu);
 #define kvm_host_pmu_init(x)	do { } while(0)
 #endif
 
+bool arm_pmu_irq_is_nmi(void);
+
 /* Internal functions only for core arm_pmu code */
 struct arm_pmu *armpmu_alloc(void);
 struct arm_pmu *armpmu_alloc_atomic(void);