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_NEED_MULTIPLE_NODES
  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
  87/**
  88 * pcpu_alloc_bootmem - NUMA friendly alloc_bootmem wrapper for percpu
  89 * @cpu: cpu to allocate for
  90 * @size: size allocation in bytes
  91 * @align: alignment
  92 *
  93 * Allocate @size bytes aligned at @align for cpu @cpu.  This wrapper
  94 * does the right thing for NUMA regardless of the current
  95 * configuration.
  96 *
  97 * RETURNS:
  98 * Pointer to the allocated area on success, NULL on failure.
  99 */
 100static void * __init pcpu_alloc_bootmem(unsigned int cpu, unsigned long size,
 101                                        unsigned long align)
 102{
 103        const unsigned long goal = __pa(MAX_DMA_ADDRESS);
 104#ifdef CONFIG_NEED_MULTIPLE_NODES
 105        int node = early_cpu_to_node(cpu);
 106        void *ptr;
 107
 108        if (!node_online(node) || !NODE_DATA(node)) {
 109                ptr = memblock_alloc_from(size, align, goal);
 110                pr_info("cpu %d has no node %d or node-local memory\n",
 111                        cpu, node);
 112                pr_debug("per cpu data for cpu%d %lu bytes at %016lx\n",
 113                         cpu, size, __pa(ptr));
 114        } else {
 115                ptr = memblock_alloc_try_nid(size, align, goal,
 116                                             MEMBLOCK_ALLOC_ACCESSIBLE,
 117                                             node);
 118
 119                pr_debug("per cpu data for cpu%d %lu bytes on node%d at %016lx\n",
 120                         cpu, size, node, __pa(ptr));
 121        }
 122        return ptr;
 123#else
 124        return memblock_alloc_from(size, align, goal);
 125#endif
 126}
 127
 128/*
 129 * Helpers for first chunk memory allocation
 130 */
 131static void * __init pcpu_fc_alloc(unsigned int cpu, size_t size, size_t align)
 132{
 133        return pcpu_alloc_bootmem(cpu, size, align);
 134}
 135
 136static void __init pcpu_fc_free(void *ptr, size_t size)
 137{
 138        memblock_free(__pa(ptr), size);
 139}
 140
 141static int __init pcpu_cpu_distance(unsigned int from, unsigned int to)
 142{
 143#ifdef CONFIG_NEED_MULTIPLE_NODES
 144        if (early_cpu_to_node(from) == early_cpu_to_node(to))
 145                return LOCAL_DISTANCE;
 146        else
 147                return REMOTE_DISTANCE;
 148#else
 149        return LOCAL_DISTANCE;
 150#endif
 151}
 152
 153static void __init pcpup_populate_pte(unsigned long addr)
 154{
 155        populate_extra_pte(addr);
 156}
 157
 158static inline void setup_percpu_segment(int cpu)
 159{
 160#ifdef CONFIG_X86_32
 161        struct desc_struct d = GDT_ENTRY_INIT(0x8092, per_cpu_offset(cpu),
 162                                              0xFFFFF);
 163
 164        write_gdt_entry(get_cpu_gdt_rw(cpu), GDT_ENTRY_PERCPU, &d, DESCTYPE_S);
 165#endif
 166}
 167
 168void __init setup_per_cpu_areas(void)
 169{
 170        unsigned int cpu;
 171        unsigned long delta;
 172        int rc;
 173
 174        pr_info("NR_CPUS:%d nr_cpumask_bits:%d nr_cpu_ids:%u nr_node_ids:%u\n",
 175                NR_CPUS, nr_cpumask_bits, nr_cpu_ids, nr_node_ids);
 176
 177        /*
 178         * Allocate percpu area.  Embedding allocator is our favorite;
 179         * however, on NUMA configurations, it can result in very
 180         * sparse unit mapping and vmalloc area isn't spacious enough
 181         * on 32bit.  Use page in that case.
 182         */
 183#ifdef CONFIG_X86_32
 184        if (pcpu_chosen_fc == PCPU_FC_AUTO && pcpu_need_numa())
 185                pcpu_chosen_fc = PCPU_FC_PAGE;
 186#endif
 187        rc = -EINVAL;
 188        if (pcpu_chosen_fc != PCPU_FC_PAGE) {
 189                const size_t dyn_size = PERCPU_MODULE_RESERVE +
 190                        PERCPU_DYNAMIC_RESERVE - PERCPU_FIRST_CHUNK_RESERVE;
 191                size_t atom_size;
 192
 193                /*
 194                 * On 64bit, use PMD_SIZE for atom_size so that embedded
 195                 * percpu areas are aligned to PMD.  This, in the future,
 196                 * can also allow using PMD mappings in vmalloc area.  Use
 197                 * PAGE_SIZE on 32bit as vmalloc space is highly contended
 198                 * and large vmalloc area allocs can easily fail.
 199                 */
 200#ifdef CONFIG_X86_64
 201                atom_size = PMD_SIZE;
 202#else
 203                atom_size = PAGE_SIZE;
 204#endif
 205                rc = pcpu_embed_first_chunk(PERCPU_FIRST_CHUNK_RESERVE,
 206                                            dyn_size, atom_size,
 207                                            pcpu_cpu_distance,
 208                                            pcpu_fc_alloc, pcpu_fc_free);
 209                if (rc < 0)
 210                        pr_warn("%s allocator failed (%d), falling back to page size\n",
 211                                pcpu_fc_names[pcpu_chosen_fc], rc);
 212        }
 213        if (rc < 0)
 214                rc = pcpu_page_first_chunk(PERCPU_FIRST_CHUNK_RESERVE,
 215                                           pcpu_fc_alloc, pcpu_fc_free,
 216                                           pcpup_populate_pte);
 217        if (rc < 0)
 218                panic("cannot initialize percpu area (err=%d)", rc);
 219
 220        /* alrighty, percpu areas up and running */
 221        delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
 222        for_each_possible_cpu(cpu) {
 223                per_cpu_offset(cpu) = delta + pcpu_unit_offsets[cpu];
 224                per_cpu(this_cpu_off, cpu) = per_cpu_offset(cpu);
 225                per_cpu(cpu_number, cpu) = cpu;
 226                setup_percpu_segment(cpu);
 227                setup_stack_canary_segment(cpu);
 228                /*
 229                 * Copy data used in early init routines from the
 230                 * initial arrays to the per cpu data areas.  These
 231                 * arrays then become expendable and the *_early_ptr's
 232                 * are zeroed indicating that the static arrays are
 233                 * gone.
 234                 */
 235#ifdef CONFIG_X86_LOCAL_APIC
 236                per_cpu(x86_cpu_to_apicid, cpu) =
 237                        early_per_cpu_map(x86_cpu_to_apicid, cpu);
 238                per_cpu(x86_bios_cpu_apicid, cpu) =
 239                        early_per_cpu_map(x86_bios_cpu_apicid, cpu);
 240                per_cpu(x86_cpu_to_acpiid, cpu) =
 241                        early_per_cpu_map(x86_cpu_to_acpiid, cpu);
 242#endif
 243#ifdef CONFIG_X86_32
 244                per_cpu(x86_cpu_to_logical_apicid, cpu) =
 245                        early_per_cpu_map(x86_cpu_to_logical_apicid, cpu);
 246#endif
 247#ifdef CONFIG_NUMA
 248                per_cpu(x86_cpu_to_node_map, cpu) =
 249                        early_per_cpu_map(x86_cpu_to_node_map, cpu);
 250                /*
 251                 * Ensure that the boot cpu numa_node is correct when the boot
 252                 * cpu is on a node that doesn't have memory installed.
 253                 * Also cpu_up() will call cpu_to_node() for APs when
 254                 * MEMORY_HOTPLUG is defined, before per_cpu(numa_node) is set
 255                 * up later with c_init aka intel_init/amd_init.
 256                 * So set them all (boot cpu and all APs).
 257                 */
 258                set_cpu_numa_node(cpu, early_cpu_to_node(cpu));
 259#endif
 260                /*
 261                 * Up to this point, the boot CPU has been using .init.data
 262                 * area.  Reload any changed state for the boot CPU.
 263                 */
 264                if (!cpu)
 265                        switch_to_new_gdt(cpu);
 266        }
 267
 268        /* indicate the early static arrays will soon be gone */
 269#ifdef CONFIG_X86_LOCAL_APIC
 270        early_per_cpu_ptr(x86_cpu_to_apicid) = NULL;
 271        early_per_cpu_ptr(x86_bios_cpu_apicid) = NULL;
 272        early_per_cpu_ptr(x86_cpu_to_acpiid) = NULL;
 273#endif
 274#ifdef CONFIG_X86_32
 275        early_per_cpu_ptr(x86_cpu_to_logical_apicid) = NULL;
 276#endif
 277#ifdef CONFIG_NUMA
 278        early_per_cpu_ptr(x86_cpu_to_node_map) = NULL;
 279#endif
 280
 281        /* Setup node to cpumask map */
 282        setup_node_to_cpumask_map();
 283
 284        /* Setup cpu initialized, callin, callout masks */
 285        setup_cpu_local_masks();
 286
 287        /*
 288         * Sync back kernel address range again.  We already did this in
 289         * setup_arch(), but percpu data also needs to be available in
 290         * the smpboot asm and arch_sync_kernel_mappings() doesn't sync to
 291         * swapper_pg_dir on 32-bit. The per-cpu mappings need to be available
 292         * there too.
 293         *
 294         * FIXME: Can the later sync in setup_cpu_entry_areas() replace
 295         * this call?
 296         */
 297        sync_initial_page_table();
 298}
 299