From: Mark Rutland <mark.rutland@arm.com> To: Douglas Anderson <dianders@chromium.org> Cc: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>, Sumit Garg <sumit.garg@linaro.org>, Daniel Thompson <daniel.thompson@linaro.org>, Marc Zyngier <maz@kernel.org>, linux-perf-users@vger.kernel.org, ito-yuichi@fujitsu.com, Chen-Yu Tsai <wens@csie.org>, Ard Biesheuvel <ardb@kernel.org>, Stephen Boyd <swboyd@chromium.org>, Peter Zijlstra <peterz@infradead.org>, Thomas Gleixner <tglx@linutronix.de>, linux-arm-kernel@lists.infradead.org, kgdb-bugreport@lists.sourceforge.net, Masayoshi Mizuma <msys.mizuma@gmail.com>, "Rafael J . Wysocki" <rafael.j.wysocki@intel.com>, Lecopzer Chen <lecopzer.chen@mediatek.com>, linux-kernel@vger.kernel.org Subject: Re: [PATCH v9 5/7] arm64: ipi_debug: Add support for backtrace using the debug IPI Date: Mon, 7 Aug 2023 11:23:44 +0100 [thread overview] Message-ID: <ZNDGMJW01avOMShn@FVFF77S0Q05N.cambridge.arm.com> (raw) In-Reply-To: <20230601143109.v9.5.I65981105e1f62550b0316625dd1e599deaf9e1aa@changeid> On Thu, Jun 01, 2023 at 02:31:49PM -0700, Douglas Anderson wrote: > From: Sumit Garg <sumit.garg@linaro.org> > > Enable arch_trigger_cpumask_backtrace() support on arm64 using the new > debug IPI. With this arm64 can now get backtraces in cases where > callers of the trigger_xyz_backtrace() class of functions don't check > the return code and implement a fallback. One example is > `kernel.softlockup_all_cpu_backtrace`. This also allows us to > backtrace hard locked up CPUs in cases where the debug IPI is backed > by an NMI (or pseudo NMI). > > Signed-off-by: Sumit Garg <sumit.garg@linaro.org> > Signed-off-by: Douglas Anderson <dianders@chromium.org> > --- > > Changes in v9: > - Added comments that we might not be using NMI always. > - Renamed "NMI IPI" to "debug IPI" since it might not be backed by NMI. > - arch_trigger_cpumask_backtrace() no longer returns bool > > Changes in v8: > - Removed "#ifdef CONFIG_SMP" since arm64 is always SMP > > arch/arm64/include/asm/irq.h | 3 +++ > arch/arm64/kernel/ipi_debug.c | 25 +++++++++++++++++++++++-- > 2 files changed, 26 insertions(+), 2 deletions(-) As with prior patches, I'd prefer if this lived in smp.c with the other IPI logic. > > diff --git a/arch/arm64/include/asm/irq.h b/arch/arm64/include/asm/irq.h > index fac08e18bcd5..be2d103f316e 100644 > --- a/arch/arm64/include/asm/irq.h > +++ b/arch/arm64/include/asm/irq.h > @@ -6,6 +6,9 @@ > > #include <asm-generic/irq.h> > > +void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self); > +#define arch_trigger_cpumask_backtrace arch_trigger_cpumask_backtrace > + > struct pt_regs; > > int set_handle_irq(void (*handle_irq)(struct pt_regs *)); > diff --git a/arch/arm64/kernel/ipi_debug.c b/arch/arm64/kernel/ipi_debug.c > index b57833e31eaf..6984ed507e1f 100644 > --- a/arch/arm64/kernel/ipi_debug.c > +++ b/arch/arm64/kernel/ipi_debug.c > @@ -8,6 +8,7 @@ > > #include <linux/interrupt.h> > #include <linux/irq.h> > +#include <linux/nmi.h> > #include <linux/smp.h> > > #include "ipi_debug.h" > @@ -24,11 +25,31 @@ void arm64_debug_ipi(cpumask_t *mask) > __ipi_send_mask(ipi_debug_desc, mask); > } > > +void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self) > +{ > + /* > + * NOTE: though nmi_trigger_cpumask_backtrace has "nmi_" in the name, > + * nothing about it truly needs to be backed by an NMI, it's just that > + * it's _allowed_ to be called from an NMI. If set_smp_debug_ipi() > + * failed to get an NMI (or pseudo-NMI) this will just be backed by a > + * regular IPI. > + */ > + nmi_trigger_cpumask_backtrace(mask, exclude_self, arm64_debug_ipi); > +} > + > static irqreturn_t ipi_debug_handler(int irq, void *data) > { > - /* nop, NMI handlers for special features can be added here. */ > + irqreturn_t ret = IRQ_NONE; > + > + /* > + * NOTE: Just like in arch_trigger_cpumask_backtrace(), we're calling > + * a function with "nmi_" in the name but it works fine even if we > + * are using a regulaor IPI. > + */ > + if (nmi_cpu_backtrace(get_irq_regs())) > + ret = IRQ_HANDLED; > Does this need the printk_deferred_{enter,exit}() that 32-bit arm has? Thanks, Mark. > - return IRQ_NONE; > + return ret; > } > > void debug_ipi_setup(void) > -- > 2.41.0.rc2.161.g9c6817b8e7-goog >
WARNING: multiple messages have this Message-ID (diff)
From: Mark Rutland <mark.rutland@arm.com> To: Douglas Anderson <dianders@chromium.org> Cc: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>, Sumit Garg <sumit.garg@linaro.org>, Daniel Thompson <daniel.thompson@linaro.org>, Marc Zyngier <maz@kernel.org>, linux-perf-users@vger.kernel.org, ito-yuichi@fujitsu.com, Chen-Yu Tsai <wens@csie.org>, Ard Biesheuvel <ardb@kernel.org>, Stephen Boyd <swboyd@chromium.org>, Peter Zijlstra <peterz@infradead.org>, Thomas Gleixner <tglx@linutronix.de>, linux-arm-kernel@lists.infradead.org, kgdb-bugreport@lists.sourceforge.net, Masayoshi Mizuma <msys.mizuma@gmail.com>, "Rafael J . Wysocki" <rafael.j.wysocki@intel.com>, Lecopzer Chen <lecopzer.chen@mediatek.com>, linux-kernel@vger.kernel.org Subject: Re: [PATCH v9 5/7] arm64: ipi_debug: Add support for backtrace using the debug IPI Date: Mon, 7 Aug 2023 11:23:44 +0100 [thread overview] Message-ID: <ZNDGMJW01avOMShn@FVFF77S0Q05N.cambridge.arm.com> (raw) In-Reply-To: <20230601143109.v9.5.I65981105e1f62550b0316625dd1e599deaf9e1aa@changeid> On Thu, Jun 01, 2023 at 02:31:49PM -0700, Douglas Anderson wrote: > From: Sumit Garg <sumit.garg@linaro.org> > > Enable arch_trigger_cpumask_backtrace() support on arm64 using the new > debug IPI. With this arm64 can now get backtraces in cases where > callers of the trigger_xyz_backtrace() class of functions don't check > the return code and implement a fallback. One example is > `kernel.softlockup_all_cpu_backtrace`. This also allows us to > backtrace hard locked up CPUs in cases where the debug IPI is backed > by an NMI (or pseudo NMI). > > Signed-off-by: Sumit Garg <sumit.garg@linaro.org> > Signed-off-by: Douglas Anderson <dianders@chromium.org> > --- > > Changes in v9: > - Added comments that we might not be using NMI always. > - Renamed "NMI IPI" to "debug IPI" since it might not be backed by NMI. > - arch_trigger_cpumask_backtrace() no longer returns bool > > Changes in v8: > - Removed "#ifdef CONFIG_SMP" since arm64 is always SMP > > arch/arm64/include/asm/irq.h | 3 +++ > arch/arm64/kernel/ipi_debug.c | 25 +++++++++++++++++++++++-- > 2 files changed, 26 insertions(+), 2 deletions(-) As with prior patches, I'd prefer if this lived in smp.c with the other IPI logic. > > diff --git a/arch/arm64/include/asm/irq.h b/arch/arm64/include/asm/irq.h > index fac08e18bcd5..be2d103f316e 100644 > --- a/arch/arm64/include/asm/irq.h > +++ b/arch/arm64/include/asm/irq.h > @@ -6,6 +6,9 @@ > > #include <asm-generic/irq.h> > > +void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self); > +#define arch_trigger_cpumask_backtrace arch_trigger_cpumask_backtrace > + > struct pt_regs; > > int set_handle_irq(void (*handle_irq)(struct pt_regs *)); > diff --git a/arch/arm64/kernel/ipi_debug.c b/arch/arm64/kernel/ipi_debug.c > index b57833e31eaf..6984ed507e1f 100644 > --- a/arch/arm64/kernel/ipi_debug.c > +++ b/arch/arm64/kernel/ipi_debug.c > @@ -8,6 +8,7 @@ > > #include <linux/interrupt.h> > #include <linux/irq.h> > +#include <linux/nmi.h> > #include <linux/smp.h> > > #include "ipi_debug.h" > @@ -24,11 +25,31 @@ void arm64_debug_ipi(cpumask_t *mask) > __ipi_send_mask(ipi_debug_desc, mask); > } > > +void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self) > +{ > + /* > + * NOTE: though nmi_trigger_cpumask_backtrace has "nmi_" in the name, > + * nothing about it truly needs to be backed by an NMI, it's just that > + * it's _allowed_ to be called from an NMI. If set_smp_debug_ipi() > + * failed to get an NMI (or pseudo-NMI) this will just be backed by a > + * regular IPI. > + */ > + nmi_trigger_cpumask_backtrace(mask, exclude_self, arm64_debug_ipi); > +} > + > static irqreturn_t ipi_debug_handler(int irq, void *data) > { > - /* nop, NMI handlers for special features can be added here. */ > + irqreturn_t ret = IRQ_NONE; > + > + /* > + * NOTE: Just like in arch_trigger_cpumask_backtrace(), we're calling > + * a function with "nmi_" in the name but it works fine even if we > + * are using a regulaor IPI. > + */ > + if (nmi_cpu_backtrace(get_irq_regs())) > + ret = IRQ_HANDLED; > Does this need the printk_deferred_{enter,exit}() that 32-bit arm has? Thanks, Mark. > - return IRQ_NONE; > + return ret; > } > > void debug_ipi_setup(void) > -- > 2.41.0.rc2.161.g9c6817b8e7-goog > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2023-08-07 10:23 UTC|newest] Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-06-01 21:31 [PATCH v9 0/7] arm64: Add debug IPI for backtraces / kgdb; try to use NMI for it Douglas Anderson 2023-06-01 21:31 ` Douglas Anderson 2023-06-01 21:31 ` [PATCH v9 1/7] irqchip/gic-v3: Enable support for SGIs to act as NMIs Douglas Anderson 2023-06-01 21:31 ` Douglas Anderson 2023-08-07 9:50 ` Mark Rutland 2023-08-07 9:50 ` Mark Rutland 2023-08-07 11:22 ` Sumit Garg 2023-08-07 11:22 ` Sumit Garg 2023-08-07 13:25 ` Mark Rutland 2023-08-07 13:25 ` Mark Rutland 2023-06-01 21:31 ` [PATCH v9 2/7] arm64: idle: Tag the arm64 idle functions as __cpuidle Douglas Anderson 2023-06-01 21:31 ` Douglas Anderson 2023-08-07 9:52 ` Mark Rutland 2023-08-07 9:52 ` Mark Rutland 2023-06-01 21:31 ` [PATCH v9 3/7] arm64: Add framework for a debug IPI Douglas Anderson 2023-06-01 21:31 ` Douglas Anderson 2023-08-07 10:12 ` Mark Rutland 2023-08-07 10:12 ` Mark Rutland 2023-08-21 22:16 ` Doug Anderson 2023-08-21 22:16 ` Doug Anderson 2023-08-22 6:42 ` Mark Rutland 2023-08-22 6:42 ` Mark Rutland 2023-06-01 21:31 ` [PATCH v9 4/7] arm64: smp: Assign and setup the " Douglas Anderson 2023-06-01 21:31 ` Douglas Anderson 2023-08-07 10:17 ` Mark Rutland 2023-08-07 10:17 ` Mark Rutland 2023-06-01 21:31 ` [PATCH v9 5/7] arm64: ipi_debug: Add support for backtrace using " Douglas Anderson 2023-06-01 21:31 ` Douglas Anderson 2023-08-07 10:23 ` Mark Rutland [this message] 2023-08-07 10:23 ` Mark Rutland 2023-08-22 0:06 ` Doug Anderson 2023-08-22 0:06 ` Doug Anderson 2023-08-22 6:35 ` Mark Rutland 2023-08-22 6:35 ` Mark Rutland 2023-06-01 21:31 ` [PATCH v9 6/7] kgdb: Provide a stub kgdb_nmicallback() if !CONFIG_KGDB Douglas Anderson 2023-06-01 21:31 ` Douglas Anderson 2023-06-15 18:14 ` Doug Anderson 2023-06-15 18:14 ` Doug Anderson 2023-06-26 14:30 ` Daniel Thompson 2023-06-26 14:30 ` Daniel Thompson 2023-08-07 10:27 ` Mark Rutland 2023-08-07 10:27 ` Mark Rutland 2023-08-07 10:29 ` Mark Rutland 2023-08-07 10:29 ` Mark Rutland 2023-06-01 21:31 ` [PATCH v9 7/7] arm64: kgdb: Roundup cpus using the debug IPI Douglas Anderson 2023-06-01 21:31 ` Douglas Anderson 2023-08-07 10:28 ` Mark Rutland 2023-08-07 10:28 ` Mark Rutland 2023-08-07 10:47 ` Marc Zyngier 2023-08-07 10:47 ` Marc Zyngier 2023-08-07 10:54 ` Mark Rutland 2023-08-07 10:54 ` Mark Rutland 2023-08-07 11:08 ` Marc Zyngier 2023-08-07 11:08 ` Marc Zyngier 2023-08-07 11:13 ` Mark Rutland 2023-08-07 11:13 ` Mark Rutland 2023-08-07 15:24 ` Daniel Thompson 2023-08-07 15:24 ` Daniel Thompson 2023-08-07 16:04 ` Mark Rutland 2023-08-07 16:04 ` Mark Rutland 2023-08-08 11:17 ` Daniel Thompson 2023-08-08 11:17 ` Daniel Thompson 2023-06-02 5:19 ` [PATCH v9 0/7] arm64: Add debug IPI for backtraces / kgdb; try to use NMI for it Sumit Garg 2023-06-02 5:19 ` Sumit Garg 2023-07-24 15:55 ` Doug Anderson 2023-08-07 10:41 ` Mark Rutland 2023-08-07 10:41 ` Mark Rutland 2023-08-07 12:46 ` Sumit Garg 2023-08-07 12:46 ` Sumit Garg 2023-08-07 14:43 ` Mark Rutland 2023-08-07 14:43 ` Mark Rutland
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