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| author | James Morse <james.morse@arm.com> | 2023-11-21 14:44:15 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-12-06 04:41:48 +0100 |
| commit | a02f66bb3cf475947b58dd3851b987b8ccd998c1 (patch) | |
| tree | 19a267b2f96880a8107fa5f4bb01180e4054c333 /arch/x86/Kconfig | |
| parent | Loongarch: remove arch_*register_cpu() exports (diff) | |
| download | linux-a02f66bb3cf475947b58dd3851b987b8ccd998c1.tar.xz linux-a02f66bb3cf475947b58dd3851b987b8ccd998c1.zip | |
ACPI: Move ACPI_HOTPLUG_CPU to be disabled on arm64 and riscv
Neither arm64 nor riscv support physical hotadd of CPUs that were not
present at boot. For arm64 much of the platform description is in static
tables which do not have update methods. arm64 does support HOTPLUG_CPU,
which is backed by a firmware interface to turn CPUs on and off.
acpi_processor_hotadd_init() and acpi_processor_remove() are for adding
and removing CPUs that were not present at boot. arm64 systems that do this
are not supported as there is currently insufficient information in the
platform description. (e.g. did the GICR get removed too?)
arm64 currently relies on the MADT enabled flag check in map_gicc_mpidr()
to prevent CPUs that were not described as present at boot from being
added to the system. Similarly, riscv relies on the same check in
map_rintc_hartid(). Both architectures also rely on the weak 'always fails'
definitions of acpi_map_cpu() and arch_register_cpu().
Subsequent changes will redefine ACPI_HOTPLUG_CPU as making possible
CPUs present. Neither arm64 nor riscv support this.
Disable ACPI_HOTPLUG_CPU for arm64 and riscv by removing 'default y' and
selecting it on the other three ACPI architectures. This allows the weak
definitions of some symbols to be removed.
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/E1r5R31-00Csyt-Jq@rmk-PC.armlinux.org.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 3762f41bb092..dbdcfc708369 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -59,6 +59,7 @@ config X86 # select ACPI_LEGACY_TABLES_LOOKUP if ACPI select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI + select ACPI_HOTPLUG_CPU if ACPI_PROCESSOR && HOTPLUG_CPU select ARCH_32BIT_OFF_T if X86_32 select ARCH_CLOCKSOURCE_INIT select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE |