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Thu, 04 May 2023 15:15:37 -0700 (PDT) Received: from tictac2.mtv.corp.google.com ([2620:15c:9d:2:edf0:7321:6b9e:d5e7]) by smtp.gmail.com with ESMTPSA id g26-20020aa7819a000000b006437c0edf9csm169615pfi.16.2023.05.04.15.15.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 04 May 2023 15:15:36 -0700 (PDT) From: Douglas Anderson To: Petr Mladek , Andrew Morton Cc: Sumit Garg , Mark Rutland , Matthias Kaehlcke , Stephane Eranian , Stephen Boyd , ricardo.neri@intel.com, Tzung-Bi Shih , Lecopzer Chen , kgdb-bugreport@lists.sourceforge.net, Masayoshi Mizuma , Guenter Roeck , Pingfan Liu , Andi Kleen , Ian Rogers , linux-arm-kernel@lists.infradead.org, linux-perf-users@vger.kernel.org, ito-yuichi@fujitsu.com, Randy Dunlap , Chen-Yu Tsai , christophe.leroy@csgroup.eu, davem@davemloft.net, sparclinux@vger.kernel.org, mpe@ellerman.id.au, Will Deacon , ravi.v.shankar@intel.com, npiggin@gmail.com, linuxppc-dev@lists.ozlabs.org, Marc Zyngier , Catalin Marinas , Daniel Thompson , Douglas Anderson Subject: [PATCH v4 17/17] arm64: Enable perf events based hard lockup detector Date: Thu, 4 May 2023 15:13:49 -0700 Message-ID: <20230504151100.v4.17.Ia44852044cdcb074f387e80df6b45e892965d4a1@changeid> X-Mailer: git-send-email 2.40.1.521.gf1e218fcd8-goog In-Reply-To: <20230504221349.1535669-1-dianders@chromium.org> References: <20230504221349.1535669-1-dianders@chromium.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230504_151541_811649_0F843B58 X-CRM114-Status: GOOD ( 28.88 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.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, override arch_perf_nmi_is_available() to let the watchdog framework know PMU not ready, and inform the framework to re-initialize lockup detection once PMU has been initialized. Co-developed-by: Sumit Garg Signed-off-by: Sumit Garg Co-developed-by: Pingfan Liu Signed-off-by: Pingfan Liu Signed-off-by: Lecopzer Chen Signed-off-by: Douglas Anderson --- I yanked this patch from the mailing lists [1] into my series just to make it easier to avoid conflicts between my series and the one adding the arm64 perf hardlockup detector, in case someone wanted to test them both together. As part of making this match with my series, I needed to resolve conflicts with the patch ("watchdog/hardlockup: Have the perf hardlockup use __weak functions more cleanly"). This makes ${SUBJECT} patch now depend on the patch ("watchdog/perf: Add a weak function for an arch to detect if perf can use NMIs"). As talked about in that patch, there may be better alternatives to accomplish the same thing. As mentioned in the cover letter, I'm not really expecting this patch to land together with the patches for the buddy detector. I included it with my series simply for convenience of testing both series together. NOTE: the previous patch posted by Lecopzer pointed to Sumit's patch [2] in the commit text but provided no context. I moved it to this "after the cut" note. [1] https://lore.kernel.org/r/20220903093415.15850-7-lecopzer.chen@mediatek.com/ [2] http://lore.kernel.org/linux-arm-kernel/1610712101-14929-1-git-send-email-sumit.garg@linaro.org Changes in v4: - Pulled ("Enable perf events based hard ...") into my series for v4. arch/arm64/Kconfig | 2 ++ arch/arm64/kernel/perf_event.c | 12 ++++++++++-- arch/arm64/kernel/watchdog_hld.c | 12 ++++++++++++ drivers/perf/arm_pmu.c | 5 +++++ include/linux/perf/arm_pmu.h | 2 ++ 5 files changed, 31 insertions(+), 2 deletions(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 1023e896d46b..4ee9f3a7bc7a 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -197,12 +197,14 @@ 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 select HAVE_KVM select HAVE_NMI 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 dde06c0f97f3..732bc5d76cb1 100644 --- a/arch/arm64/kernel/perf_event.c +++ b/arch/arm64/kernel/perf_event.c @@ -23,6 +23,7 @@ #include #include #include +#include /* ARMv8 Cortex-A53 specific event types. */ #define ARMV8_A53_PERFCTR_PREF_LINEFILL 0xC2 @@ -1396,10 +1397,17 @@ 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) + lockup_detector_retry_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 2401eb1b7e55..dcd25322127c 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 #include +#include /* * Safe maximum CPU frequency in case a particular platform doesn't implement @@ -22,3 +24,13 @@ u64 hw_nmi_get_sample_period(int watchdog_thresh) return (u64)max_cpu_freq * watchdog_thresh; } + +bool __init arch_perf_nmi_is_available(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. + */ + return arm_pmu_irq_is_nmi(); +} diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c index 15bd1e34a88e..7b9caa502d33 100644 --- a/drivers/perf/arm_pmu.c +++ b/drivers/perf/arm_pmu.c @@ -687,6 +687,11 @@ 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 525b5d64e394..5b00f5cb4cf9 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); void armpmu_free(struct arm_pmu *pmu);