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SubjectRe: [PATCH v8 05/16] ACPI: processor: Add acpi_get_processor_handle() helper
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On 4/26/24 23:51, Jonathan Cameron wrote:
> If CONFIG_ACPI_PROCESSOR provide a helper to retrieve the
> acpi_handle for a given CPU allowing access to methods
> in DSDT.
>
> Tested-by: Miguel Luis <miguel.luis@oracle.com>
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
>
> ---
> v8: Code simplification suggested by Rafael.
> Fixup ;; spotted by Gavin
> ---
> drivers/acpi/acpi_processor.c | 11 +++++++++++
> include/linux/acpi.h | 7 +++++++
> 2 files changed, 18 insertions(+)
>

Reviewed-by: Gavin Shan <gshan@redhat.com>

> diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
> index 3b180e21f325..ecc2721fecae 100644
> --- a/drivers/acpi/acpi_processor.c
> +++ b/drivers/acpi/acpi_processor.c
> @@ -35,6 +35,17 @@ EXPORT_PER_CPU_SYMBOL(processors);
> struct acpi_processor_errata errata __read_mostly;
> EXPORT_SYMBOL_GPL(errata);
>
> +acpi_handle acpi_get_processor_handle(int cpu)
> +{
> + struct acpi_processor *pr;
> +
> + pr = per_cpu(processors, cpu);
> + if (pr)
> + return pr->handle;
> +
> + return NULL;
> +}
> +

Maybe it's worthy to have more check here, something like below.
However, it's also fine without the extra check.

if (cpu >= nr_cpu_ids || !cpu_possible(cpu))
return NULL;

> static int acpi_processor_errata_piix4(struct pci_dev *dev)
> {
> u8 value1 = 0;
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index 34829f2c517a..9844a3f9c4e5 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -309,6 +309,8 @@ int acpi_map_cpu(acpi_handle handle, phys_cpuid_t physid, u32 acpi_id,
> int acpi_unmap_cpu(int cpu);
> #endif /* CONFIG_ACPI_HOTPLUG_CPU */
>
> +acpi_handle acpi_get_processor_handle(int cpu);
> +
> #ifdef CONFIG_ACPI_HOTPLUG_IOAPIC
> int acpi_get_ioapic_id(acpi_handle handle, u32 gsi_base, u64 *phys_addr);
> #endif
> @@ -1077,6 +1079,11 @@ static inline bool acpi_sleep_state_supported(u8 sleep_state)
> return false;
> }
>
> +static inline acpi_handle acpi_get_processor_handle(int cpu)
> +{
> + return NULL;
> +}
> +
> #endif /* !CONFIG_ACPI */
>
> extern void arch_post_acpi_subsys_init(void);

Thanks,
Gavin


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