From: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> To: Geoff Levand <geoff@infradead.org> Cc: "linux-arm-kernel@lists.infradead.org" <linux-arm-kernel@lists.infradead.org>, "linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>, "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>, Mark Rutland <Mark.Rutland@arm.com>, Paul Walmsley <paul@pwsan.com>, Vincent Guittot <vincent.guittot@linaro.org>, Kevin Hilman <khilman@linaro.org>, Nicolas Pitre <nico@linaro.org>, Catalin Marinas <Catalin.Marinas@arm.com>, Peter De Schrijver <pdeschrijver@nvidia.com>, Daniel Lezcano <daniel.lezcano@linaro.org>, Stephen Boyd <sboyd@codeaurora.org>, Amit Kucheria <amit.kucheria@linaro.org>, Chander Kashyap <chander.kashyap@linaro.org>, Sebastian Capella <sebcape@gmail.com>, Rob Herring <robh+dt@kernel.org>, Santosh Shilimkar <santosh.shilimkar@ti.com>, Mark Brown <broonie@kernel.org>, Sudeep Holla <Sudeep.Holla@arm.com>, "grant.likely@linaro.org" <grant.likely@linaro.org> Subject: Re: [PATCH v5 4/8] arm64: add PSCI CPU_SUSPEND based cpu_suspend support Date: Thu, 26 Jun 2014 17:55:05 +0100 [thread overview] Message-ID: <20140626165505.GD27364@e102568-lin.cambridge.arm.com> (raw) In-Reply-To: <1403729520.11749.64.camel@smoke> Hi Geoff, On Wed, Jun 25, 2014 at 09:52:00PM +0100, Geoff Levand wrote: > Hi Lorenzo, > > On Wed, 2014-06-25 at 15:10 +0100, Lorenzo Pieralisi wrote: > > diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c > > > + /* > > + * This is belt-and-braces: make sure that if the idle > > + * specified protocol is psci, the cpu_ops have been > > + * initialized to psci operations. Anything else is > > + * a recipe for mayhem. > > + */ > > + for_each_cpu(cpu, drv->cpumask) { > > + cpu_ops_ptr = cpu_ops[cpu]; > > + if (WARN_ON(!cpu_ops_ptr || strcmp(cpu_ops_ptr->name, "psci"))) > > + return -EOPNOTSUPP; > > + } > > I'm not sure how drv->cpumask is setup, but if a system has mixed enable > methods, say some cpus 'spin-table' and some 'psci', will this give a > false error? I do not think that's a false error. If the idle states specify an entry-method == psci, and cpu_ops for some cpus are not set to PSCI, obviously because the enable-method specified that, that's a firmware bug. > If drv->cpumask should only include 'psci' cpus, then should this be a > BUG()? Ok, if we got here, it is because the idle-states entry-method was set to PSCI. Now, if any of the CPUs in the driver mask has a cpu_ops pointer != PSCI, we have a problem and we should warn on that. I do not think that justifies a BUG_ON, but that's one of those things, it is debatable. Question is whether the check should also be carried out at cpu_ops initialization (ie to check for mixed cpu_ops), for certain if the idle states entry-method is PSCI and cpu_ops != PSCI we should WARN/BUG on that. Or embed this idle state parameters initialization at cpu_ops init (see other thread you started) so that we can kill two birds with one stone. > > + > > + psci_states = kcalloc(drv->state_count, sizeof(*psci_states), > > + GFP_KERNEL); > > + > > + if (!psci_states) { > > + pr_warn("psci idle state allocation failed\n"); > > + return -ENOMEM; > > + } > > + > > + for_each_cpu(cpu, drv->cpumask) { > > + if (per_cpu(psci_power_state, cpu)) { > > + pr_warn("idle states already initialized on cpu %u\n", > > + cpu); > > This seems like an implementation problem, if so, shouldn't this be > pr_debug()? Maybe, I will give it some thought. > > #endif > > > > +#ifdef CONFIG_ARM64_CPU_SUSPEND > > +static int cpu_psci_cpu_suspend(unsigned long index) > > +{ > > + struct psci_power_state *state = __get_cpu_var(psci_power_state); > > + > > + if (!state) > > + return -EOPNOTSUPP; > > + > > + return psci_ops.cpu_suspend(state[index], virt_to_phys(cpu_resume)); > > +} > > +#endif > > Why not put a __maybe_unused attribute on cpu_psci_cpu_suspend() and > remove the preprocessor conditional. That way this code will always be > compiled, and with therefor always get a build test. The linker should > strip out the unused code when CONFIG_ARM64_CPU_SUSPEND=n and the code > below is not compiled. It can make sense, yes. Thanks, Lorenzo
WARNING: multiple messages have this Message-ID (diff)
From: lorenzo.pieralisi@arm.com (Lorenzo Pieralisi) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v5 4/8] arm64: add PSCI CPU_SUSPEND based cpu_suspend support Date: Thu, 26 Jun 2014 17:55:05 +0100 [thread overview] Message-ID: <20140626165505.GD27364@e102568-lin.cambridge.arm.com> (raw) In-Reply-To: <1403729520.11749.64.camel@smoke> Hi Geoff, On Wed, Jun 25, 2014 at 09:52:00PM +0100, Geoff Levand wrote: > Hi Lorenzo, > > On Wed, 2014-06-25 at 15:10 +0100, Lorenzo Pieralisi wrote: > > diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c > > > + /* > > + * This is belt-and-braces: make sure that if the idle > > + * specified protocol is psci, the cpu_ops have been > > + * initialized to psci operations. Anything else is > > + * a recipe for mayhem. > > + */ > > + for_each_cpu(cpu, drv->cpumask) { > > + cpu_ops_ptr = cpu_ops[cpu]; > > + if (WARN_ON(!cpu_ops_ptr || strcmp(cpu_ops_ptr->name, "psci"))) > > + return -EOPNOTSUPP; > > + } > > I'm not sure how drv->cpumask is setup, but if a system has mixed enable > methods, say some cpus 'spin-table' and some 'psci', will this give a > false error? I do not think that's a false error. If the idle states specify an entry-method == psci, and cpu_ops for some cpus are not set to PSCI, obviously because the enable-method specified that, that's a firmware bug. > If drv->cpumask should only include 'psci' cpus, then should this be a > BUG()? Ok, if we got here, it is because the idle-states entry-method was set to PSCI. Now, if any of the CPUs in the driver mask has a cpu_ops pointer != PSCI, we have a problem and we should warn on that. I do not think that justifies a BUG_ON, but that's one of those things, it is debatable. Question is whether the check should also be carried out at cpu_ops initialization (ie to check for mixed cpu_ops), for certain if the idle states entry-method is PSCI and cpu_ops != PSCI we should WARN/BUG on that. Or embed this idle state parameters initialization at cpu_ops init (see other thread you started) so that we can kill two birds with one stone. > > + > > + psci_states = kcalloc(drv->state_count, sizeof(*psci_states), > > + GFP_KERNEL); > > + > > + if (!psci_states) { > > + pr_warn("psci idle state allocation failed\n"); > > + return -ENOMEM; > > + } > > + > > + for_each_cpu(cpu, drv->cpumask) { > > + if (per_cpu(psci_power_state, cpu)) { > > + pr_warn("idle states already initialized on cpu %u\n", > > + cpu); > > This seems like an implementation problem, if so, shouldn't this be > pr_debug()? Maybe, I will give it some thought. > > #endif > > > > +#ifdef CONFIG_ARM64_CPU_SUSPEND > > +static int cpu_psci_cpu_suspend(unsigned long index) > > +{ > > + struct psci_power_state *state = __get_cpu_var(psci_power_state); > > + > > + if (!state) > > + return -EOPNOTSUPP; > > + > > + return psci_ops.cpu_suspend(state[index], virt_to_phys(cpu_resume)); > > +} > > +#endif > > Why not put a __maybe_unused attribute on cpu_psci_cpu_suspend() and > remove the preprocessor conditional. That way this code will always be > compiled, and with therefor always get a build test. The linker should > strip out the unused code when CONFIG_ARM64_CPU_SUSPEND=n and the code > below is not compiled. It can make sense, yes. Thanks, Lorenzo
next prev parent reply other threads:[~2014-06-26 16:55 UTC|newest] Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top 2014-06-25 14:10 [PATCH v5 0/8] ARM generic idle states Lorenzo Pieralisi 2014-06-25 14:10 ` Lorenzo Pieralisi 2014-06-25 14:10 ` [PATCH v5 1/8] Documentation: arm: define DT idle states bindings Lorenzo Pieralisi 2014-06-25 14:10 ` Lorenzo Pieralisi 2014-06-25 14:58 ` Mark Rutland 2014-06-25 14:58 ` Mark Rutland 2014-06-25 17:37 ` Lorenzo Pieralisi 2014-06-25 17:37 ` Lorenzo Pieralisi 2014-06-26 18:32 ` Rob Herring 2014-06-26 18:32 ` Rob Herring 2014-06-27 10:53 ` Lorenzo Pieralisi 2014-06-27 10:53 ` Lorenzo Pieralisi 2014-06-25 15:56 ` Nicolas Pitre 2014-06-25 15:56 ` Nicolas Pitre 2014-06-26 10:17 ` Lorenzo Pieralisi 2014-06-26 10:17 ` Lorenzo Pieralisi 2014-06-26 19:30 ` Nicolas Pitre 2014-06-26 19:30 ` Nicolas Pitre 2014-06-25 14:10 ` [PATCH v5 2/8] Documentation: devicetree: psci: define CPU suspend parameter Lorenzo Pieralisi 2014-06-25 14:10 ` Lorenzo Pieralisi 2014-06-25 14:10 ` [PATCH v5 3/8] drivers: cpuidle: implement DT based idle states infrastructure Lorenzo Pieralisi 2014-06-25 14:10 ` Lorenzo Pieralisi 2014-06-25 15:59 ` Mark Rutland 2014-06-25 15:59 ` Mark Rutland 2014-06-26 16:01 ` Lorenzo Pieralisi 2014-06-26 16:01 ` Lorenzo Pieralisi [not found] ` <1403705421-17597-1-git-send-email-lorenzo.pieralisi-5wv7dgnIgG8@public.gmane.org> 2014-06-25 14:10 ` [PATCH v5 4/8] arm64: add PSCI CPU_SUSPEND based cpu_suspend support Lorenzo Pieralisi 2014-06-25 14:10 ` Lorenzo Pieralisi 2014-06-25 16:09 ` Mark Rutland 2014-06-25 16:09 ` Mark Rutland 2014-06-26 11:23 ` Lorenzo Pieralisi 2014-06-26 11:23 ` Lorenzo Pieralisi 2014-06-25 20:52 ` Geoff Levand 2014-06-25 20:52 ` Geoff Levand 2014-06-26 16:55 ` Lorenzo Pieralisi [this message] 2014-06-26 16:55 ` Lorenzo Pieralisi 2014-06-25 14:10 ` [PATCH v5 5/8] drivers: cpuidle: CPU idle ARM64 driver Lorenzo Pieralisi 2014-06-25 14:10 ` Lorenzo Pieralisi 2014-06-25 20:34 ` Geoff Levand 2014-06-25 20:34 ` Geoff Levand 2014-06-25 14:10 ` [PATCH v5 6/8] drivers: cpuidle: initialize big.LITTLE driver through DT Lorenzo Pieralisi 2014-06-25 14:10 ` Lorenzo Pieralisi 2014-06-25 15:06 ` Mark Rutland 2014-06-25 15:06 ` Mark Rutland 2014-06-25 16:44 ` Lorenzo Pieralisi 2014-06-25 16:44 ` Lorenzo Pieralisi 2014-06-25 14:10 ` [PATCH v5 7/8] drivers: cpuidle: initialize Exynos " Lorenzo Pieralisi 2014-06-25 14:10 ` Lorenzo Pieralisi 2014-06-25 15:13 ` Mark Rutland 2014-06-25 15:13 ` Mark Rutland 2014-06-25 16:58 ` Lorenzo Pieralisi 2014-06-25 16:58 ` Lorenzo Pieralisi 2014-06-25 15:23 ` Bartlomiej Zolnierkiewicz 2014-06-25 15:23 ` Bartlomiej Zolnierkiewicz 2014-06-26 15:16 ` Lorenzo Pieralisi 2014-06-26 15:16 ` Lorenzo Pieralisi 2014-07-17 14:20 ` Lorenzo Pieralisi 2014-07-17 14:20 ` Lorenzo Pieralisi 2014-07-18 8:45 ` Chander Kashyap 2014-07-18 8:45 ` Chander Kashyap 2014-07-18 16:10 ` Bartlomiej Zolnierkiewicz 2014-07-18 16:10 ` Bartlomiej Zolnierkiewicz 2014-06-25 14:10 ` [PATCH v5 8/8] arm64: boot: dts: update rtsm aemv8 dts with PSCI and idle states Lorenzo Pieralisi 2014-06-25 14:10 ` Lorenzo Pieralisi 2014-06-25 14:27 ` Mark Rutland 2014-06-25 14:27 ` Mark Rutland 2014-06-25 17:47 ` Lorenzo Pieralisi 2014-06-25 17:47 ` Lorenzo Pieralisi 2014-06-25 14:29 ` Sudeep Holla 2014-06-25 14:29 ` Sudeep Holla
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