diff options
| author | James Morse <james.morse@arm.com> | 2023-02-15 10:58:05 +0000 |
|---|---|---|
| committer | Russell King (Oracle) <rmk+kernel@armlinux.org.uk> | 2023-12-11 09:43:21 +0000 |
| commit | 3b35dbceb706dd5ec0930d8f7eb397f07e871a1b (patch) | |
| tree | 7c0078298274d67517ca9728de8b3f4ff1f67f9b /arch/x86/Kconfig | |
| parent | 9fbc73173853f68cadee7970781a939782d62767 (diff) | |
ACPI: Add _OSC bits to advertise OS support for toggling CPU present/enabled
Platform firmware can disabled a CPU, or make it not-present by making
an eject-request notification, then waiting for the os to make it offline
and call _EJx. After the firmware updates _STA with the new status.
Not all operating systems support this. For arm64 making CPUs not-present
has never been supported. For all ACPI architectures, making CPUs disabled
has recently been added. Firmware can't know what the OS has support for.
Add two new _OSC bits to advertise whether the OS supports the _STA enabled
or present bits being toggled for CPUs. This will be important for arm64
if systems that support physical CPU hotplug ever appear as arm64 linux
doesn't currently support this, so firmware shouldn't try.
Advertising this support to firmware is useful for cloud orchestrators
to know whether they can scale a particular VM by adding CPUs.
Signed-off-by: James Morse <james.morse@arm.com>
Tested-by: Miguel Luis <miguel.luis@oracle.com>
Tested-by: Vishnu Pajjuri <vishnu@os.amperecomputing.com>
Tested-by: Jianyong Wu <jianyong.wu@arm.com>
---
I'm assuming Loongarch machines do not support physical CPU hotplug.
Changes since RFC v3:
* Drop ia64 changes
* Update James' comment below "---" to remove reference to ia64
Outstanding comment:
https://lore.kernel.org/r/20230914175021.000018fd@Huawei.com
Diffstat (limited to 'arch/x86/Kconfig')
| -rw-r--r-- | arch/x86/Kconfig | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 64fc7c475ab0..33fc4dcd950c 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -60,6 +60,7 @@ config X86 select ACPI_LEGACY_TABLES_LOOKUP if ACPI select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI select ACPI_HOTPLUG_PRESENT_CPU if ACPI_PROCESSOR && HOTPLUG_CPU + select ACPI_HOTPLUG_IGNORE_OSC if ACPI && HOTPLUG_CPU select ARCH_32BIT_OFF_T if X86_32 select ARCH_CLOCKSOURCE_INIT select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE |