| Message ID | 20230913163823.7880-2-james.morse@arm.com (mailing list archive) |
|---|---|
| State | RFC, archived |
| Headers | show |
| Series | ACPI/arm64: add support for virtual cpuhotplug | expand |
On Wed, Sep 13, 2023 at 04:37:49PM +0000, James Morse wrote: > diff --git a/arch/loongarch/include/asm/cpu.h b/arch/loongarch/include/asm/cpu.h > index 48b9f7168bcc..7afe8cbb844e 100644 > --- a/arch/loongarch/include/asm/cpu.h > +++ b/arch/loongarch/include/asm/cpu.h > @@ -128,4 +128,11 @@ enum cpu_type_enum { > #define LOONGARCH_CPU_HYPERVISOR BIT_ULL(CPU_FEATURE_HYPERVISOR) > #define LOONGARCH_CPU_PTW BIT_ULL(CPU_FEATURE_PTW) > > +#if !defined(__ASSEMBLY__) > +#ifdef CONFIG_HOTPLUG_CPU > +int arch_register_cpu(int num); > +void arch_unregister_cpu(int cpu); > +#endif > +#endif /* ! __ASSEMBLY__ */ So, for loongarch: grep arch_.*register_cpu arch/loongarch/ -r arch/loongarch/kernel/topology.c:int arch_register_cpu(int cpu) arch/loongarch/kernel/topology.c:EXPORT_SYMBOL(arch_register_cpu); arch/loongarch/kernel/topology.c:void arch_unregister_cpu(int cpu) arch/loongarch/kernel/topology.c:EXPORT_SYMBOL(arch_unregister_cpu); So really this is a fix (since these functions should have prototypes) and thus should probably be a separate patch. However, I also wonder whether these prototypes should be added to linux/cpu.h and be done with it (rather than have every arch prototype these - it's not like the prototype can be different from this because of the generic code. I know in subsequent patches you do that, but it's rather piecemeal, and I think this is a change that could be submitted now as both a fix and clean up.
diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig index 53faa122b0f4..a3bfd42467ab 100644 --- a/arch/ia64/Kconfig +++ b/arch/ia64/Kconfig @@ -16,6 +16,7 @@ config IA64 select ARCH_MIGHT_HAVE_PC_PARPORT select ARCH_MIGHT_HAVE_PC_SERIO select ACPI + select ACPI_HOTPLUG_CPU if ACPI_PROCESSOR && HOTPLUG_CPU select ACPI_NUMA if NUMA select ARCH_ENABLE_MEMORY_HOTPLUG select ARCH_ENABLE_MEMORY_HOTREMOVE diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig index e14396a2ddcb..2bddd202470e 100644 --- a/arch/loongarch/Kconfig +++ b/arch/loongarch/Kconfig @@ -5,6 +5,7 @@ config LOONGARCH select ACPI select ACPI_GENERIC_GSI if ACPI select ACPI_MCFG if ACPI + select ACPI_HOTPLUG_CPU if ACPI_PROCESSOR && HOTPLUG_CPU select ACPI_PPTT if ACPI select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI select ARCH_BINFMT_ELF_STATE diff --git a/arch/loongarch/include/asm/cpu.h b/arch/loongarch/include/asm/cpu.h index 48b9f7168bcc..7afe8cbb844e 100644 --- a/arch/loongarch/include/asm/cpu.h +++ b/arch/loongarch/include/asm/cpu.h @@ -128,4 +128,11 @@ enum cpu_type_enum { #define LOONGARCH_CPU_HYPERVISOR BIT_ULL(CPU_FEATURE_HYPERVISOR) #define LOONGARCH_CPU_PTW BIT_ULL(CPU_FEATURE_PTW) +#if !defined(__ASSEMBLY__) +#ifdef CONFIG_HOTPLUG_CPU +int arch_register_cpu(int num); +void arch_unregister_cpu(int cpu); +#endif +#endif /* ! __ASSEMBLY__ */ + #endif /* _ASM_CPU_H */ diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 982b777eadc7..a0100a1ab4a0 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_CPU if ACPI_PROCESSOR && HOTPLUG_CPU select ARCH_32BIT_OFF_T if X86_32 select ARCH_CLOCKSOURCE_INIT select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig index cee82b473dc5..8456d48ba702 100644 --- a/drivers/acpi/Kconfig +++ b/drivers/acpi/Kconfig @@ -309,7 +309,6 @@ config ACPI_HOTPLUG_CPU bool depends on ACPI_PROCESSOR && HOTPLUG_CPU select ACPI_CONTAINER - default y config ACPI_PROCESSOR_AGGREGATOR tristate "Processor Aggregator" diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c index c711db8a9c33..c0839bcf78c1 100644 --- a/drivers/acpi/acpi_processor.c +++ b/drivers/acpi/acpi_processor.c @@ -183,24 +183,6 @@ static void __init acpi_pcc_cpufreq_init(void) {} /* Initialization */ #ifdef CONFIG_ACPI_HOTPLUG_CPU -int __weak acpi_map_cpu(acpi_handle handle, - phys_cpuid_t physid, u32 acpi_id, int *pcpu) -{ - return -ENODEV; -} - -int __weak acpi_unmap_cpu(int cpu) -{ - return -ENODEV; -} - -int __weak arch_register_cpu(int cpu) -{ - return -ENODEV; -} - -void __weak arch_unregister_cpu(int cpu) {} - static int acpi_processor_hotadd_init(struct acpi_processor *pr) { unsigned long long sta;
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> --- Changes since RFC: * Expanded conditions to avoid ACPI_HOTPLUG_CPU being enabled when HOTPLUG_CPU isn't. --- arch/ia64/Kconfig | 1 + arch/loongarch/Kconfig | 1 + arch/loongarch/include/asm/cpu.h | 7 +++++++ arch/x86/Kconfig | 1 + drivers/acpi/Kconfig | 1 - drivers/acpi/acpi_processor.c | 18 ------------------ 6 files changed, 10 insertions(+), 19 deletions(-)