Messages in this thread Patch in this message | | | From | Conor Dooley <> | Subject | [RFC 4/4] arm64: arch-topology move arm64 to the generic store_cpu_topology() | Date | Thu, 7 Jul 2022 23:04:37 +0100 |
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From: Conor Dooley <conor.dooley@microchip.com>
The default implementation of store_cpu_topology() was derived from the arm64 implementation, but with the mpidr bits removed. Extract the mpidr bits from the arch implementation to the callsites & use the generic version.
Signed-off-by: Conor Dooley <conor.dooley@microchip.com> --- arch/arm64/kernel/smp.c | 16 +++++++++++++-- arch/arm64/kernel/topology.c | 40 ------------------------------------ 2 files changed, 14 insertions(+), 42 deletions(-)
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index 62ed361a4376..9e8acaa4c2f7 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -234,7 +234,12 @@ asmlinkage notrace void secondary_start_kernel(void) * Log the CPU info before it is marked online and might get read. */ cpuinfo_store_cpu(); - store_cpu_topology(cpu); + + /* + * Uniprocessor systems can rely on default topology values + */ + if (!(mpidr & MPIDR_UP_BITMASK)) + store_cpu_topology(cpu); /* * Enable GIC and timers. @@ -719,6 +724,7 @@ void __init smp_init_cpus(void) void __init smp_prepare_cpus(unsigned int max_cpus) { const struct cpu_operations *ops; + u64 mpidr; int err; unsigned int cpu; unsigned int this_cpu; @@ -726,7 +732,13 @@ void __init smp_prepare_cpus(unsigned int max_cpus) init_cpu_topology(); this_cpu = smp_processor_id(); - store_cpu_topology(this_cpu); + mpidr = read_cpuid_mpidr(); + + /* + * Uniprocessor systems can rely on default topology values + */ + if (!(mpidr & MPIDR_UP_BITMASK)) + store_cpu_topology(this_cpu); numa_store_cpu_info(this_cpu); numa_add_cpu(this_cpu); diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c index 869ffc4d4484..7889a00f5487 100644 --- a/arch/arm64/kernel/topology.c +++ b/arch/arm64/kernel/topology.c @@ -22,46 +22,6 @@ #include <asm/cputype.h> #include <asm/topology.h> -void store_cpu_topology(unsigned int cpuid) -{ - struct cpu_topology *cpuid_topo = &cpu_topology[cpuid]; - u64 mpidr; - - if (cpuid_topo->package_id != -1) - goto topology_populated; - - mpidr = read_cpuid_mpidr(); - - /* Uniprocessor systems can rely on default topology values */ - if (mpidr & MPIDR_UP_BITMASK) - return; - - /* - * This would be the place to create cpu topology based on MPIDR. - * - * However, it cannot be trusted to depict the actual topology; some - * pieces of the architecture enforce an artificial cap on Aff0 values - * (e.g. GICv3's ICC_SGI1R_EL1 limits it to 15), leading to an - * artificial cycling of Aff1, Aff2 and Aff3 values. IOW, these end up - * having absolutely no relationship to the actual underlying system - * topology, and cannot be reasonably used as core / package ID. - * - * If the MT bit is set, Aff0 *could* be used to define a thread ID, but - * we still wouldn't be able to obtain a sane core ID. This means we - * need to entirely ignore MPIDR for any topology deduction. - */ - cpuid_topo->thread_id = -1; - cpuid_topo->core_id = cpuid; - cpuid_topo->package_id = cpu_to_node(cpuid); - - pr_debug("CPU%u: cluster %d core %d thread %d mpidr %#016llx\n", - cpuid, cpuid_topo->package_id, cpuid_topo->core_id, - cpuid_topo->thread_id, mpidr); - -topology_populated: - update_siblings_masks(cpuid); -} - #ifdef CONFIG_ACPI static bool __init acpi_cpu_is_threaded(int cpu) { -- 2.37.0
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