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
Co-developed-by: Sumit Garg <sumit.garg@linaro.org>
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Co-developed-by: Pingfan Liu <kernelfans@gmail.com>
Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
Signed-off-by: Lecopzer Chen <lecopzer.chen@mediatek.com>
---
arch/arm64/Kconfig | 2 ++
arch/arm64/kernel/perf_event.c | 12 ++++++++++--
arch/arm64/kernel/watchdog_hld.c | 14 ++++++++++++++
drivers/perf/arm_pmu.c | 5 +++++
include/linux/perf/arm_pmu.h | 2 ++
5 files changed, 33 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 9fb9fff08c94..9ec7d3d7a0ac 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -189,6 +189,7 @@ config ARM64
select HAVE_FUNCTION_ERROR_INJECTION
select HAVE_FUNCTION_GRAPH_TRACER
select HAVE_GCC_PLUGINS
+ select HAVE_HARDLOCKUP_DETECTOR_PERF if PERF_EVENTS && HAVE_PERF_EVENTS_NMI
select HAVE_HW_BREAKPOINT if PERF_EVENTS
select HAVE_IOREMAP_PROT
select HAVE_IRQ_TIME_ACCOUNTING
@@ -196,6 +197,7 @@ config ARM64
select HAVE_NMI
select HAVE_PATA_PLATFORM
select HAVE_PERF_EVENTS
+ select HAVE_PERF_EVENTS_NMI if ARM64_PSEUDO_NMI
select HAVE_PERF_REGS
select HAVE_PERF_USER_STACK_DUMP
select HAVE_PREEMPT_DYNAMIC_KEY
diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index cb69ff1e6138..d9eec8911bf0 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
@@ -1390,10 +1391,17 @@ 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_pmu_init);
+ ret = arm_pmu_acpi_probe(armv8_pmuv3_pmu_init);
+
+ if (!ret)
+ retry_lockup_detector_init();
+
+ return ret;
}
device_initcall(armv8_pmu_driver_init)
diff --git a/arch/arm64/kernel/watchdog_hld.c b/arch/arm64/kernel/watchdog_hld.c
index de43318e4dd6..c9c6ec889c15 100644
--- a/arch/arm64/kernel/watchdog_hld.c
+++ b/arch/arm64/kernel/watchdog_hld.c
@@ -1,5 +1,7 @@
// 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
@@ -23,3 +25,15 @@ u64 hw_nmi_get_sample_period(int watchdog_thresh)
return (u64)max_cpu_freq * watchdog_thresh;
}
+int __init watchdog_nmi_probe(void)
+{
+ /*
+ * hardlockup_detector_perf_init() will success even if Pseudo-NMI turns off,
+ * however, the pmu interrupts will act like a normal interrupt instead of
+ * NMI and the hardlockup detector would be broken.
+ */
+ 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 59d3980b8ca2..ceee2c55d436 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 0407a38b470a..29c56c92bab7 100644
--- a/include/linux/perf/arm_pmu.h
+++ b/include/linux/perf/arm_pmu.h
@@ -171,6 +171,8 @@ 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);
--
2.34.1
Hi Lecopzer, Thank you for the patch! Yet something to improve: [auto build test ERROR on arm64/for-next/core] [also build test ERROR on arm/for-next soc/for-next linus/master v6.0-rc4 next-20220901] [cannot apply to 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#_base_tree_information] url: https://github.com/intel-lab-lkp/linux/commits/Lecopzer-Chen/Support-hld-delayed-init-based-on-Pseudo-NMI-for/20220903-173641 base: https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-next/core config: arm64-randconfig-c033-20220904 (https://download.01.org/0day-ci/archive/20220905/202209050639.jDaWd49E-lkp@intel.com/config) compiler: aarch64-linux-gcc (GCC) 12.1.0 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/intel-lab-lkp/linux/commit/de75eba8785b631eb168737fbff6dc31418cb852 git remote add linux-review https://github.com/intel-lab-lkp/linux git fetch --no-tags linux-review Lecopzer-Chen/Support-hld-delayed-init-based-on-Pseudo-NMI-for/20220903-173641 git checkout de75eba8785b631eb168737fbff6dc31418cb852 # save the config file mkdir build_dir && cp config build_dir/.config COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=arm64 SHELL=/bin/bash If you fix the issue, kindly add following tag where applicable Reported-by: kernel test robot <lkp@intel.com> All errors (new ones prefixed by >>): aarch64-linux-ld: Unexpected GOT/PLT entries detected! aarch64-linux-ld: Unexpected run-time procedure linkages detected! aarch64-linux-ld: arch/arm64/kernel/perf_event.o: in function `armv8_pmu_driver_init': >> arch/arm64/kernel/perf_event.c:1402: undefined reference to `retry_lockup_detector_init' vim +1402 arch/arm64/kernel/perf_event.c 1391 1392 static int __init armv8_pmu_driver_init(void) 1393 { 1394 int ret; 1395 1396 if (acpi_disabled) 1397 ret = platform_driver_register(&armv8_pmu_driver); 1398 else 1399 ret = arm_pmu_acpi_probe(armv8_pmuv3_pmu_init); 1400 1401 if (!ret) > 1402 retry_lockup_detector_init(); 1403 1404 return ret; 1405 } 1406 device_initcall(armv8_pmu_driver_init) 1407 -- 0-DAY CI Kernel Test Service https://01.org/lkp
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