LXR linux/arch/x86/kernel/setup

   1#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   2
   3#include <linux/kernel.h>
   4#include <linux/module.h>
   5#include <linux/init.h>
   6#include <linux/bootmem.h>
   7#include <linux/percpu.h>
   8#include <linux/kexec.h>
   9#include <linux/crash_dump.h>
  10#include <linux/smp.h>
  11#include <linux/topology.h>
  12#include <linux/pfn.h>
  13#include <asm/sections.h>
  14#include <asm/processor.h>
  15#include <asm/setup.h>
  16#include <asm/mpspec.h>
  17#include <asm/apicdef.h>
  18#include <asm/highmem.h>
  19#include <asm/proto.h>
  20#include <asm/cpumask.h>
  21#include <asm/cpu.h>
  22#include <asm/stackprotector.h>
  23
  24DEFINE_PER_CPU(int, cpu_number);
  25EXPORT_PER_CPU_SYMBOL(cpu_number);
  26
  27#ifdef CONFIG_X86_64
  28#define BOOT_PERCPU_OFFSET ((unsigned long)__per_cpu_load)
  29#else
  30#define BOOT_PERCPU_OFFSET 0
  31#endif
  32
  33DEFINE_PER_CPU(unsigned long, this_cpu_off) = BOOT_PERCPU_OFFSET;
  34EXPORT_PER_CPU_SYMBOL(this_cpu_off);
  35
  36unsigned long __per_cpu_offset[NR_CPUS] __read_mostly = {
  37        [0 ... NR_CPUS-1] = BOOT_PERCPU_OFFSET,
  38};
  39EXPORT_SYMBOL(__per_cpu_offset);
  40
  41/*
  42 * On x86_64 symbols referenced from code should be reachable using
  43 * 32bit relocations.  Reserve space for static percpu variables in
  44 * modules so that they are always served from the first chunk which
  45 * is located at the percpu segment base.  On x86_32, anything can
  46 * address anywhere.  No need to reserve space in the first chunk.
  47 */
  48#ifdef CONFIG_X86_64
  49#define PERCPU_FIRST_CHUNK_RESERVE      PERCPU_MODULE_RESERVE
  50#else
  51#define PERCPU_FIRST_CHUNK_RESERVE      0
  52#endif
  53
  54#ifdef CONFIG_X86_32
  55/**
  56 * pcpu_need_numa - determine percpu allocation needs to consider NUMA
  57 *
  58 * If NUMA is not configured or there is only one NUMA node available,
  59 * there is no reason to consider NUMA.  This function determines
  60 * whether percpu allocation should consider NUMA or not.
  61 *
  62 * RETURNS:
  63 * true if NUMA should be considered; otherwise, false.
  64 */
  65static bool __init pcpu_need_numa(void)
  66{
  67#ifdef CONFIG_NEED_MULTIPLE_NODES
  68        pg_data_t *last = NULL;
  69        unsigned int cpu;
  70
  71        for_each_possible_cpu(cpu) {
  72                int node = early_cpu_to_node(cpu);
  73
  74                if (node_online(node) && NODE_DATA(node) &&
  75                    last && last != NODE_DATA(node))
  76                        return true;
  77
  78                last = NODE_DATA(node);
  79        }
  80#endif
  81        return false;
  82}
  83#endif
  84
  85/**
  86 * pcpu_alloc_bootmem - NUMA friendly alloc_bootmem wrapper for percpu
  87 * @cpu: cpu to allocate for
  88 * @size: size allocation in bytes
  89 * @align: alignment
  90 *
  91 * Allocate @size bytes aligned at @align for cpu @cpu.  This wrapper
  92 * does the right thing for NUMA regardless of the current
  93 * configuration.
  94 *
  95 * RETURNS:
  96 * Pointer to the allocated area on success, NULL on failure.
  97 */
  98static void * __init pcpu_alloc_bootmem(unsigned int cpu, unsigned long size,
  99                                        unsigned long align)
 100{
 101        const unsigned long goal = __pa(MAX_DMA_ADDRESS);
 102#ifdef CONFIG_NEED_MULTIPLE_NODES
 103        int node = early_cpu_to_node(cpu);
 104        void *ptr;
 105
 106        if (!node_online(node) || !NODE_DATA(node)) {
 107                ptr = __alloc_bootmem_nopanic(size, align, goal);
 108                pr_info("cpu %d has no node %d or node-local memory\n",
 109                        cpu, node);
 110                pr_debug("per cpu data for cpu%d %lu bytes at %016lx\n",
 111                         cpu, size, __pa(ptr));
 112        } else {
 113                ptr = __alloc_bootmem_node_nopanic(NODE_DATA(node),
 114                                                   size, align, goal);
 115                pr_debug("per cpu data for cpu%d %lu bytes on node%d at %016lx\n",
 116                         cpu, size, node, __pa(ptr));
 117        }
 118        return ptr;
 119#else
 120        return __alloc_bootmem_nopanic(size, align, goal);
 121#endif
 122}
 123
 124/*
 125 * Helpers for first chunk memory allocation
 126 */
 127static void * __init pcpu_fc_alloc(unsigned int cpu, size_t size, size_t align)
 128{
 129        return pcpu_alloc_bootmem(cpu, size, align);
 130}
 131
 132static void __init pcpu_fc_free(void *ptr, size_t size)
 133{
 134        free_bootmem(__pa(ptr), size);
 135}
 136
 137static int __init pcpu_cpu_distance(unsigned int from, unsigned int to)
 138{
 139#ifdef CONFIG_NEED_MULTIPLE_NODES
 140        if (early_cpu_to_node(from) == early_cpu_to_node(to))
 141                return LOCAL_DISTANCE;
 142        else
 143                return REMOTE_DISTANCE;
 144#else
 145        return LOCAL_DISTANCE;
 146#endif
 147}
 148
 149static void __init pcpup_populate_pte(unsigned long addr)
 150{
 151        populate_extra_pte(addr);
 152}
 153
 154static inline void setup_percpu_segment(int cpu)
 155{
 156#ifdef CONFIG_X86_32
 157        struct desc_struct gdt;
 158
 159        pack_descriptor(&gdt, per_cpu_offset(cpu), 0xFFFFF,
 160                        0x2 | DESCTYPE_S, 0x8);
 161        gdt.s = 1;
 162        write_gdt_entry(get_cpu_gdt_table(cpu),
 163                        GDT_ENTRY_PERCPU, &gdt, DESCTYPE_S);
 164#endif
 165}
 166
 167void __init setup_per_cpu_areas(void)
 168{
 169        unsigned int cpu;
 170        unsigned long delta;
 171        int rc;
 172
 173        pr_info("NR_CPUS:%d nr_cpumask_bits:%d nr_cpu_ids:%d nr_node_ids:%d\n",
 174                NR_CPUS, nr_cpumask_bits, nr_cpu_ids, nr_node_ids);
 175
 176        /*
 177         * Allocate percpu area.  Embedding allocator is our favorite;
 178         * however, on NUMA configurations, it can result in very
 179         * sparse unit mapping and vmalloc area isn't spacious enough
 180         * on 32bit.  Use page in that case.
 181         */
 182#ifdef CONFIG_X86_32
 183        if (pcpu_chosen_fc == PCPU_FC_AUTO && pcpu_need_numa())
 184                pcpu_chosen_fc = PCPU_FC_PAGE;
 185#endif
 186        rc = -EINVAL;
 187        if (pcpu_chosen_fc != PCPU_FC_PAGE) {
 188                const size_t atom_size = cpu_has_pse ? PMD_SIZE : PAGE_SIZE;
 189                const size_t dyn_size = PERCPU_MODULE_RESERVE +
 190                        PERCPU_DYNAMIC_RESERVE - PERCPU_FIRST_CHUNK_RESERVE;
 191
 192                rc = pcpu_embed_first_chunk(PERCPU_FIRST_CHUNK_RESERVE,
 193                                            dyn_size, atom_size,
 194                                            pcpu_cpu_distance,
 195                                            pcpu_fc_alloc, pcpu_fc_free);
 196                if (rc < 0)
 197                        pr_warning("%s allocator failed (%d), falling back to page size\n",
 198                                   pcpu_fc_names[pcpu_chosen_fc], rc);
 199        }
 200        if (rc < 0)
 201                rc = pcpu_page_first_chunk(PERCPU_FIRST_CHUNK_RESERVE,
 202                                           pcpu_fc_alloc, pcpu_fc_free,
 203                                           pcpup_populate_pte);
 204        if (rc < 0)
 205                panic("cannot initialize percpu area (err=%d)", rc);
 206
 207        /* alrighty, percpu areas up and running */
 208        delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
 209        for_each_possible_cpu(cpu) {
 210                per_cpu_offset(cpu) = delta + pcpu_unit_offsets[cpu];
 211                per_cpu(this_cpu_off, cpu) = per_cpu_offset(cpu);
 212                per_cpu(cpu_number, cpu) = cpu;
 213                setup_percpu_segment(cpu);
 214                setup_stack_canary_segment(cpu);
 215                /*
 216                 * Copy data used in early init routines from the
 217                 * initial arrays to the per cpu data areas.  These
 218                 * arrays then become expendable and the *_early_ptr's
 219                 * are zeroed indicating that the static arrays are
 220                 * gone.
 221                 */
 222#ifdef CONFIG_X86_LOCAL_APIC
 223                per_cpu(x86_cpu_to_apicid, cpu) =
 224                        early_per_cpu_map(x86_cpu_to_apicid, cpu);
 225                per_cpu(x86_bios_cpu_apicid, cpu) =
 226                        early_per_cpu_map(x86_bios_cpu_apicid, cpu);
 227#endif
 228#ifdef CONFIG_X86_64
 229                per_cpu(irq_stack_ptr, cpu) =
 230                        per_cpu(irq_stack_union.irq_stack, cpu) +
 231                        IRQ_STACK_SIZE - 64;
 232#ifdef CONFIG_NUMA
 233                per_cpu(x86_cpu_to_node_map, cpu) =
 234                        early_per_cpu_map(x86_cpu_to_node_map, cpu);
 235                /*
 236                 * Ensure that the boot cpu numa_node is correct when the boot
 237                 * cpu is on a node that doesn't have memory installed.
 238                 * Also cpu_up() will call cpu_to_node() for APs when
 239                 * MEMORY_HOTPLUG is defined, before per_cpu(numa_node) is set
 240                 * up later with c_init aka intel_init/amd_init.
 241                 * So set them all (boot cpu and all APs).
 242                 */
 243                set_cpu_numa_node(cpu, early_cpu_to_node(cpu));
 244#endif
 245#endif
 246                /*
 247                 * Up to this point, the boot CPU has been using .init.data
 248                 * area.  Reload any changed state for the boot CPU.
 249                 */
 250                if (!cpu)
 251                        switch_to_new_gdt(cpu);
 252        }
 253
 254        /* indicate the early static arrays will soon be gone */
 255#ifdef CONFIG_X86_LOCAL_APIC
 256        early_per_cpu_ptr(x86_cpu_to_apicid) = NULL;
 257        early_per_cpu_ptr(x86_bios_cpu_apicid) = NULL;
 258#endif
 259#if defined(CONFIG_X86_64) && defined(CONFIG_NUMA)
 260        early_per_cpu_ptr(x86_cpu_to_node_map) = NULL;
 261#endif
 262
 263        /* Setup node to cpumask map */
 264        setup_node_to_cpumask_map();
 265
 266        /* Setup cpu initialized, callin, callout masks */
 267        setup_cpu_local_masks();
 268}
 269