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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230// SPDX-License-Identifier: GPL-2.0#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>#include <linux/export.h>#include <linux/init.h>#include <linux/memblock.h>#include <linux/percpu.h>#include <linux/kexec.h>#include <linux/crash_dump.h>#include <linux/smp.h>#include <linux/topology.h>#include <linux/pfn.h>#include <linux/stackprotector.h>#include <asm/sections.h>#include <asm/processor.h>#include <asm/desc.h>#include <asm/setup.h>#include <asm/mpspec.h>#include <asm/apicdef.h>#include <asm/highmem.h>#include <asm/proto.h>#include <asm/cpumask.h>#include <asm/cpu.h>
DEFINE_PER_CPU_CACHE_HOT(int, cpu_number);EXPORT_PER_CPU_SYMBOL(cpu_number);
DEFINE_PER_CPU_CACHE_HOT(unsigned long, this_cpu_off);EXPORT_PER_CPU_SYMBOL(this_cpu_off);
unsigned long __per_cpu_offset[NR_CPUS] __ro_after_init;EXPORT_SYMBOL(__per_cpu_offset);
/* * On x86_64 symbols referenced from code should be reachable using * 32bit relocations. Reserve space for static percpu variables in * modules so that they are always served from the first chunk which * is located at the percpu segment base. On x86_32, anything can * address anywhere. No need to reserve space in the first chunk. */#ifdef CONFIG_X86_64#define PERCPU_FIRST_CHUNK_RESERVE PERCPU_MODULE_RESERVE#else#define PERCPU_FIRST_CHUNK_RESERVE 0#endif
#ifdef CONFIG_X86_32/** * pcpu_need_numa - determine percpu allocation needs to consider NUMA * * If NUMA is not configured or there is only one NUMA node available, * there is no reason to consider NUMA. This function determines * whether percpu allocation should consider NUMA or not. * * RETURNS: * true if NUMA should be considered; otherwise, false. */static bool __init pcpu_need_numa(void){#ifdef CONFIG_NUMA pg_data_t *last = NULL; unsigned int cpu;
for_each_possible_cpu(cpu) { int node = early_cpu_to_node(cpu);
if (node_online(node) && NODE_DATA(node) && last && last != NODE_DATA(node)) return true;
last = NODE_DATA(node); }#endif return false;}#endif
static int __init pcpu_cpu_distance(unsigned int from, unsigned int to){#ifdef CONFIG_NUMA if (early_cpu_to_node(from) == early_cpu_to_node(to)) return LOCAL_DISTANCE; else return REMOTE_DISTANCE;#else return LOCAL_DISTANCE;#endif}
static int __init pcpu_cpu_to_node(int cpu){ return early_cpu_to_node(cpu);}
void __init pcpu_populate_pte(unsigned long addr){ populate_extra_pte(addr);}
static inline void setup_percpu_segment(int cpu){#ifdef CONFIG_X86_32 struct desc_struct d = GDT_ENTRY_INIT(DESC_DATA32, per_cpu_offset(cpu), 0xFFFFF);
write_gdt_entry(get_cpu_gdt_rw(cpu), GDT_ENTRY_PERCPU, &d, DESCTYPE_S);#endif}
void __init setup_per_cpu_areas(void){ unsigned int cpu; unsigned long delta; int rc;
pr_info("NR_CPUS:%d nr_cpumask_bits:%d nr_cpu_ids:%u nr_node_ids:%u\n", NR_CPUS, nr_cpumask_bits, nr_cpu_ids, nr_node_ids);
/* * Allocate percpu area. Embedding allocator is our favorite; * however, on NUMA configurations, it can result in very * sparse unit mapping and vmalloc area isn't spacious enough * on 32bit. Use page in that case. */#ifdef CONFIG_X86_32 if (pcpu_chosen_fc == PCPU_FC_AUTO && pcpu_need_numa()) pcpu_chosen_fc = PCPU_FC_PAGE;#endif rc = -EINVAL; if (pcpu_chosen_fc != PCPU_FC_PAGE) { const size_t dyn_size = PERCPU_MODULE_RESERVE + PERCPU_DYNAMIC_RESERVE - PERCPU_FIRST_CHUNK_RESERVE; size_t atom_size;
/* * On 64bit, use PMD_SIZE for atom_size so that embedded * percpu areas are aligned to PMD. This, in the future, * can also allow using PMD mappings in vmalloc area. Use * PAGE_SIZE on 32bit as vmalloc space is highly contended * and large vmalloc area allocs can easily fail. */#ifdef CONFIG_X86_64 atom_size = PMD_SIZE;#else atom_size = PAGE_SIZE;#endif rc = pcpu_embed_first_chunk(PERCPU_FIRST_CHUNK_RESERVE, dyn_size, atom_size, pcpu_cpu_distance, pcpu_cpu_to_node); if (rc < 0) pr_warn("%s allocator failed (%d), falling back to page size\n", pcpu_fc_names[pcpu_chosen_fc], rc); } if (rc < 0) rc = pcpu_page_first_chunk(PERCPU_FIRST_CHUNK_RESERVE, pcpu_cpu_to_node); if (rc < 0) panic("cannot initialize percpu area (err=%d)", rc);
/* alrighty, percpu areas up and running */ delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start; for_each_possible_cpu(cpu) { per_cpu_offset(cpu) = delta + pcpu_unit_offsets[cpu]; per_cpu(this_cpu_off, cpu) = per_cpu_offset(cpu); per_cpu(cpu_number, cpu) = cpu; setup_percpu_segment(cpu); /* * Copy data used in early init routines from the * initial arrays to the per cpu data areas. These * arrays then become expendable and the *_early_ptr's * are zeroed indicating that the static arrays are * gone. */#ifdef CONFIG_X86_LOCAL_APIC per_cpu(x86_cpu_to_apicid, cpu) = early_per_cpu_map(x86_cpu_to_apicid, cpu); per_cpu(x86_cpu_to_acpiid, cpu) = early_per_cpu_map(x86_cpu_to_acpiid, cpu);#endif#ifdef CONFIG_NUMA per_cpu(x86_cpu_to_node_map, cpu) = early_per_cpu_map(x86_cpu_to_node_map, cpu); /* * Ensure that the boot cpu numa_node is correct when the boot * cpu is on a node that doesn't have memory installed. * Also cpu_up() will call cpu_to_node() for APs when * MEMORY_HOTPLUG is defined, before per_cpu(numa_node) is set * up later with c_init aka intel_init/amd_init. * So set them all (boot cpu and all APs). */ set_cpu_numa_node(cpu, early_cpu_to_node(cpu));#endif /* * Up to this point, the boot CPU has been using .init.data * area. Reload any changed state for the boot CPU. */ if (!cpu) switch_gdt_and_percpu_base(cpu); }
/* indicate the early static arrays will soon be gone */#ifdef CONFIG_X86_LOCAL_APIC early_per_cpu_ptr(x86_cpu_to_apicid) = NULL; early_per_cpu_ptr(x86_cpu_to_acpiid) = NULL;#endif#ifdef CONFIG_NUMA early_per_cpu_ptr(x86_cpu_to_node_map) = NULL;#endif
/* Setup node to cpumask map */ setup_node_to_cpumask_map();
/* Setup cpu initialized, callin, callout masks */ setup_cpu_local_masks();
/* * Sync back kernel address range again. We already did this in * setup_arch(), but percpu data also needs to be available in * the smpboot asm and arch_sync_kernel_mappings() doesn't sync to * swapper_pg_dir on 32-bit. The per-cpu mappings need to be available * there too. * * FIXME: Can the later sync in setup_cpu_entry_areas() replace * this call? */ sync_initial_page_table();}