Messages in this thread | | | Date | Wed, 24 Apr 2024 18:08:30 +0100 | From | Jonathan Cameron <> | Subject | Re: [PATCH v7 11/16] irqchip/gic-v3: Add support for ACPI's disabled but 'online capable' CPUs |
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On Wed, 24 Apr 2024 17:35:54 +0100 Salil Mehta <salil.mehta@huawei.com> wrote:
> > From: Marc Zyngier <maz@kernel.org> > > Sent: Wednesday, April 24, 2024 4:33 PM > > To: Jonathan Cameron <jonathan.cameron@huawei.com> > > Cc: Thomas Gleixner <tglx@linutronix.de>; Peter Zijlstra > > <peterz@infradead.org>; linux-pm@vger.kernel.org; > > loongarch@lists.linux.dev; linux-acpi@vger.kernel.org; linux- > > arch@vger.kernel.org; linux-kernel@vger.kernel.org; linux-arm- > > kernel@lists.infradead.org; kvmarm@lists.linux.dev; x86@kernel.org; > > Russell King <linux@armlinux.org.uk>; Rafael J . Wysocki > > <rafael@kernel.org>; Miguel Luis <miguel.luis@oracle.com>; James Morse > > <james.morse@arm.com>; Salil Mehta <salil.mehta@huawei.com>; Jean- > > Philippe Brucker <jean-philippe@linaro.org>; Catalin Marinas > > <catalin.marinas@arm.com>; Will Deacon <will@kernel.org>; Linuxarm > > <linuxarm@huawei.com>; Ingo Molnar <mingo@redhat.com>; Borislav > > Petkov <bp@alien8.de>; Dave Hansen <dave.hansen@linux.intel.com>; > > justin.he@arm.com; jianyong.wu@arm.com > > Subject: Re: [PATCH v7 11/16] irqchip/gic-v3: Add support for ACPI's > > disabled but 'online capable' CPUs > > > > On Wed, 24 Apr 2024 13:54:38 +0100, > > Jonathan Cameron <Jonathan.Cameron@huawei.com> wrote: > > > > > > On Tue, 23 Apr 2024 13:01:21 +0100 > > > Marc Zyngier <maz@kernel.org> wrote: > > > > > > > On Mon, 22 Apr 2024 11:40:20 +0100, > > > > Jonathan Cameron <Jonathan.Cameron@Huawei.com> wrote: > > > > > > > > > > On Thu, 18 Apr 2024 14:54:07 +0100 Jonathan Cameron > > > > > <Jonathan.Cameron@huawei.com> wrote: > > > > [...] > > > > > > > > > > > > > + /* > > > > > > + * Capable but disabled CPUs can be brought online later. What about > > > > > > + * the redistributor? ACPI doesn't want to say! > > > > > > + * Virtual hotplug systems can use the MADT's "always-on" GICR entries. > > > > > > + * Otherwise, prevent such CPUs from being brought online. > > > > > > + */ > > > > > > + if (!(gicc->flags & ACPI_MADT_ENABLED)) { > > > > > > + pr_warn_once("CPU %u's redistributor is inaccessible: this CPU can't be brought online\n", cpu); > > > > > > + set_cpu_present(cpu, false); > > > > > > + set_cpu_possible(cpu, false); > > (a digression) shouldn't we be clearing the enabled mask as well? > > set_cpu_enabled(cpu, false);
FWIW I think not necessary. enabled is only set in register_cpu() and aim here is to never call that for CPUs in this state.
Anyhow, I got distracted by the firmware bug I found whilst trying to test this but now have a test setup that hits this path (once deliberately broken), so will see what we can do about that doesn't have affect those masks.
Jonathan
> > > Best regards > Salil
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