[PATCH 21/39] ACPI: processor: Register all CPUs from acpi_processor_get_info()

Russell King
2023-10-24T15:21:06Z

To allow ACPI to skip the call to arch_register_cpu() when the _STA
value indicates the CPU can't be brought online right now, move the
arch_register_cpu() call into acpi_processor_get_info().

Systems can still be booted with 'acpi=off', or not include an
ACPI description at all. For these, the CPUs continue to be
registered by cpu_dev_register_generic().

This moves the CPU register logic back to a subsys_initcall(),
while the memory nodes will have been registered earlier.

Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
Changes since RFC v2:
* Fixup comment in acpi_processor_get_info() (Gavin Shan)
* Add comment in cpu_dev_register_generic() (Gavin Shan)
---
drivers/acpi/acpi_processor.c | 12 ++++++++++++
drivers/base/cpu.c | 6 +++++-
2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
index 0511f2bc10bc..e7ed4730cbbe 100644
--- a/drivers/acpi/acpi_processor.c
+++ b/drivers/acpi/acpi_processor.c
@@ -314,6 +314,18 @@ static int acpi_processor_get_info(struct acpi_device *device)
cpufreq_add_device("acpi-cpufreq");
}

+ /*
+ * Register CPUs that are present. get_cpu_device() is used to skip
+ * duplicate CPU descriptions from firmware.
+ */
+ if (!invalid_logical_cpuid(pr->id) && cpu_present(pr->id) &&
+ !get_cpu_device(pr->id)) {
+ int ret = arch_register_cpu(pr->id);
+
+ if (ret)
+ return ret;
+ }
+
/*
* Extra Processor objects may be enumerated on MP systems with
* less than the max # of CPUs. They should be ignored _iff
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index d31c936f0955..6c70a004c198 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -537,7 +537,11 @@ static void __init cpu_dev_register_generic(void)
{
int i, ret;

- if (!IS_ENABLED(CONFIG_GENERIC_CPU_DEVICES))
+ /*
+ * When ACPI is enabled, CPUs are registered via
+ * acpi_processor_get_info().
+ */
+ if (!IS_ENABLED(CONFIG_GENERIC_CPU_DEVICES) || !acpi_disabled)
return;

for_each_present_cpu(i) {
--
2.30.2