Re: [PATCH RFC v3 10/21] ACPI: Check _STA present bit before making CPUs not present

Jonathan Cameron <[email protected]> Fri, 15 Dec 2023 16:18:03 +0000
Newsgroups org.kernel.vger.linux-ia64,dev.linux.lists.acpica-devel,dev.linux.lists.kvmarm,dev.linux.lists.loongarch,org.infradead.lists.linux-arm-kernel,org.infradead.lists.linux-riscv,org.kernel.vger.linux-acpi,org.kernel.vger.linux-arch,org.kernel.vger.linux-csky,org.kernel.vger.linux-doc,org.kernel.vger.linux-kernel,org.kernel.vger.linux-parisc,org.kernel.vger.linux-pm
Organization Huawei Technologies Research and Development (UK) Ltd.
Message-ID <[email protected]>
On Wed, 13 Dec 2023 12:50:02 +0000
Russell King (Oracle) <[email protected]> wrote:

> From: James Morse <[email protected]>
> 
> When called acpi_processor_post_eject() unconditionally make a CPU
> not-present and unregisters it.
> 
> To add support for AML events where the CPU has become disabled, but
> remains present, the _STA method should be checked before calling
> acpi_processor_remove().
> 
> Rename acpi_processor_post_eject() acpi_processor_remove_possible(), and
> check the _STA before calling.
> 
> Adding the function prototype for arch_unregister_cpu() allows the
> preprocessor guards to be removed.
> 
> After this change CPUs will remain registered and visible to
> user-space as offline if buggy firmware triggers an eject-request,
> but doesn't clear the corresponding _STA bits after _EJ0 has been
> called.
> 
> Signed-off-by: James Morse <[email protected]>
> Tested-by: Miguel Luis <[email protected]>
> Tested-by: Vishnu Pajjuri <[email protected]>
> Tested-by: Jianyong Wu <[email protected]>
LGTM
Reviewed-by: Jonathan Cameron <[email protected]>