LXR linux/arch/x86/kernel/setup

   1// SPDX-License-Identifier: GPL-2.0
   2#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   3
   4#include <linux/kernel.h>
   5#include <linux/export.h>
   6#include <linux/init.h>
   7#include <linux/memblock.h>
   8#include <linux/percpu.h>
   9#include <linux/kexec.h>
  10#include <linux/crash_dump.h>
  11#include <linux/smp.h>
  12#include <linux/topology.h>
  13#include <linux/pfn.h>
  14#include <asm/sections.h>
  15#include <asm/processor.h>
  16#include <asm/desc.h>
  17#include <asm/setup.h>
  18#include <asm/mpspec.h>
  19#include <asm/apicdef.h>
  20#include <asm/highmem.h>
  21#include <asm/proto.h>
  22#include <asm/cpumask.h>
  23#include <asm/cpu.h>
  24#include <asm/stackprotector.h>
  25
  26DEFINE_PER_CPU_READ_MOSTLY(int, cpu_number);
  27EXPORT_PER_CPU_SYMBOL(cpu_number);
  28
  29#ifdef CONFIG_X86_64
  30#define BOOT_PERCPU_OFFSET ((unsigned long)__per_cpu_load)
  31#else
  32#define BOOT_PERCPU_OFFSET 0
  33#endif
  34
  35DEFINE_PER_CPU_READ_MOSTLY(unsigned long, this_cpu_off) = BOOT_PERCPU_OFFSET;
  36EXPORT_PER_CPU_SYMBOL(this_cpu_off);
  37
  38unsigned long __per_cpu_offset[NR_CPUS] __ro_after_init = {
  39        [0 ... NR_CPUS-1] = BOOT_PERCPU_OFFSET,
  40};
  41EXPORT_SYMBOL(__per_cpu_offset);
  42
  43/*
  44 * On x86_64 symbols referenced from code should be reachable using
  45 * 32bit relocations.  Reserve space for static percpu variables in
  46 * modules so that they are always served from the first chunk which
  47 * is located at the percpu segment base.  On x86_32, anything can
  48 * address anywhere.  No need to reserve space in the first chunk.
  49 */
  50#ifdef CONFIG_X86_64
  51#define PERCPU_FIRST_CHUNK_RESERVE      PERCPU_MODULE_RESERVE
  52#else
  53#define PERCPU_FIRST_CHUNK_RESERVE      0
  54#endif
  55
  56#ifdef CONFIG_X86_32
  57/**
  58 * pcpu_need_numa - determine percpu allocation needs to consider NUMA
  59 *
  60 * If NUMA is not configured or there is only one NUMA node available,
  61 * there is no reason to consider NUMA.  This function determines
  62 * whether percpu allocation should consider NUMA or not.
  63 *
  64 * RETURNS:
  65 * true if NUMA should be considered; otherwise, false.
  66 */
  67static bool __init pcpu_need_numa(void)
  68{
  69#ifdef CONFIG_NUMA
  70        pg_data_t *last = NULL;
  71        unsigned int cpu;
  72
  73        for_each_possible_cpu(cpu) {
  74                int node = early_cpu_to_node(cpu);
  75
  76                if (node_online(node) && NODE_DATA(node) &&
  77                    last && last != NODE_DATA(node))
  78                        return true;
  79
  80                last = NODE_DATA(node);
  81        }
  82#endif
  83        return false;
  84}
  85#endif
  86
  87static int __init pcpu_cpu_distance(unsigned int from, unsigned int to)
  88{
  89#ifdef CONFIG_NUMA
  90        if (early_cpu_to_node(from) == early_cpu_to_node(to))
  91                return LOCAL_DISTANCE;
  92        else
  93                return REMOTE_DISTANCE;
  94#else
  95        return LOCAL_DISTANCE;
  96#endif
  97}
  98
  99static int __init pcpu_cpu_to_node(int cpu)
 100{
 101        return early_cpu_to_node(cpu);
 102}
 103
 104void __init pcpu_populate_pte(unsigned long addr)
 105{
 106        populate_extra_pte(addr);
 107}
 108
 109static inline void setup_percpu_segment(int cpu)
 110{
 111#ifdef CONFIG_X86_32
 112        struct desc_struct d = GDT_ENTRY_INIT(0x8092, per_cpu_offset(cpu),
 113                                              0xFFFFF);
 114
 115        write_gdt_entry(get_cpu_gdt_rw(cpu), GDT_ENTRY_PERCPU, &d, DESCTYPE_S);
 116#endif
 117}
 118
 119void __init setup_per_cpu_areas(void)
 120{
 121        unsigned int cpu;
 122        unsigned long delta;
 123        int rc;
 124
 125        pr_info("NR_CPUS:%d nr_cpumask_bits:%d nr_cpu_ids:%u nr_node_ids:%u\n",
 126                NR_CPUS, nr_cpumask_bits, nr_cpu_ids, nr_node_ids);
 127
 128        /*
 129         * Allocate percpu area.  Embedding allocator is our favorite;
 130         * however, on NUMA configurations, it can result in very
 131         * sparse unit mapping and vmalloc area isn't spacious enough
 132         * on 32bit.  Use page in that case.
 133         */
 134#ifdef CONFIG_X86_32
 135        if (pcpu_chosen_fc == PCPU_FC_AUTO && pcpu_need_numa())
 136                pcpu_chosen_fc = PCPU_FC_PAGE;
 137#endif
 138        rc = -EINVAL;
 139        if (pcpu_chosen_fc != PCPU_FC_PAGE) {
 140                const size_t dyn_size = PERCPU_MODULE_RESERVE +
 141                        PERCPU_DYNAMIC_RESERVE - PERCPU_FIRST_CHUNK_RESERVE;
 142                size_t atom_size;
 143
 144                /*
 145                 * On 64bit, use PMD_SIZE for atom_size so that embedded
 146                 * percpu areas are aligned to PMD.  This, in the future,
 147                 * can also allow using PMD mappings in vmalloc area.  Use
 148                 * PAGE_SIZE on 32bit as vmalloc space is highly contended
 149                 * and large vmalloc area allocs can easily fail.
 150                 */
 151#ifdef CONFIG_X86_64
 152                atom_size = PMD_SIZE;
 153#else
 154                atom_size = PAGE_SIZE;
 155#endif
 156                rc = pcpu_embed_first_chunk(PERCPU_FIRST_CHUNK_RESERVE,
 157                                            dyn_size, atom_size,
 158                                            pcpu_cpu_distance,
 159                                            pcpu_cpu_to_node);
 160                if (rc < 0)
 161                        pr_warn("%s allocator failed (%d), falling back to page size\n",
 162                                pcpu_fc_names[pcpu_chosen_fc], rc);
 163        }
 164        if (rc < 0)
 165                rc = pcpu_page_first_chunk(PERCPU_FIRST_CHUNK_RESERVE,
 166                                           pcpu_cpu_to_node);
 167        if (rc < 0)
 168                panic("cannot initialize percpu area (err=%d)", rc);
 169
 170        /* alrighty, percpu areas up and running */
 171        delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
 172        for_each_possible_cpu(cpu) {
 173                per_cpu_offset(cpu) = delta + pcpu_unit_offsets[cpu];
 174                per_cpu(this_cpu_off, cpu) = per_cpu_offset(cpu);
 175                per_cpu(cpu_number, cpu) = cpu;
 176                setup_percpu_segment(cpu);
 177                /*
 178                 * Copy data used in early init routines from the
 179                 * initial arrays to the per cpu data areas.  These
 180                 * arrays then become expendable and the *_early_ptr's
 181                 * are zeroed indicating that the static arrays are
 182                 * gone.
 183                 */
 184#ifdef CONFIG_X86_LOCAL_APIC
 185                per_cpu(x86_cpu_to_apicid, cpu) =
 186                        early_per_cpu_map(x86_cpu_to_apicid, cpu);
 187                per_cpu(x86_bios_cpu_apicid, cpu) =
 188                        early_per_cpu_map(x86_bios_cpu_apicid, cpu);
 189                per_cpu(x86_cpu_to_acpiid, cpu) =
 190                        early_per_cpu_map(x86_cpu_to_acpiid, cpu);
 191#endif
 192#ifdef CONFIG_X86_32
 193                per_cpu(x86_cpu_to_logical_apicid, cpu) =
 194                        early_per_cpu_map(x86_cpu_to_logical_apicid, cpu);
 195#endif
 196#ifdef CONFIG_NUMA
 197                per_cpu(x86_cpu_to_node_map, cpu) =
 198                        early_per_cpu_map(x86_cpu_to_node_map, cpu);
 199                /*
 200                 * Ensure that the boot cpu numa_node is correct when the boot
 201                 * cpu is on a node that doesn't have memory installed.
 202                 * Also cpu_up() will call cpu_to_node() for APs when
 203                 * MEMORY_HOTPLUG is defined, before per_cpu(numa_node) is set
 204                 * up later with c_init aka intel_init/amd_init.
 205                 * So set them all (boot cpu and all APs).
 206                 */
 207                set_cpu_numa_node(cpu, early_cpu_to_node(cpu));
 208#endif
 209                /*
 210                 * Up to this point, the boot CPU has been using .init.data
 211                 * area.  Reload any changed state for the boot CPU.
 212                 */
 213                if (!cpu)
 214                        switch_to_new_gdt(cpu);
 215        }
 216
 217        /* indicate the early static arrays will soon be gone */
 218#ifdef CONFIG_X86_LOCAL_APIC
 219        early_per_cpu_ptr(x86_cpu_to_apicid) = NULL;
 220        early_per_cpu_ptr(x86_bios_cpu_apicid) = NULL;
 221        early_per_cpu_ptr(x86_cpu_to_acpiid) = NULL;
 222#endif
 223#ifdef CONFIG_X86_32
 224        early_per_cpu_ptr(x86_cpu_to_logical_apicid) = NULL;
 225#endif
 226#ifdef CONFIG_NUMA
 227        early_per_cpu_ptr(x86_cpu_to_node_map) = NULL;
 228#endif
 229
 230        /* Setup node to cpumask map */
 231        setup_node_to_cpumask_map();
 232
 233        /* Setup cpu initialized, callin, callout masks */
 234        setup_cpu_local_masks();
 235
 236        /*
 237         * Sync back kernel address range again.  We already did this in
 238         * setup_arch(), but percpu data also needs to be available in
 239         * the smpboot asm and arch_sync_kernel_mappings() doesn't sync to
 240         * swapper_pg_dir on 32-bit. The per-cpu mappings need to be available
 241         * there too.
 242         *
 243         * FIXME: Can the later sync in setup_cpu_entry_areas() replace
 244         * this call?
 245         */
 246        sync_initial_page_table();
 247}
 248