arch/x86/kernel/setup_percpu.c

   1 #include <linux/kernel.h>
   2 #include <linux/module.h>
   3 #include <linux/init.h>
   4 #include <linux/bootmem.h>
   5 #include <linux/percpu.h>
   6 #include <linux/kexec.h>
   7 #include <linux/crash_dump.h>
   8 #include <linux/smp.h>
   9 #include <linux/topology.h>
  10 #include <linux/pfn.h>
  11 #include <asm/sections.h>
  12 #include <asm/processor.h>
  13 #include <asm/setup.h>
  14 #include <asm/mpspec.h>
  15 #include <asm/apicdef.h>
  16 #include <asm/highmem.h>
  17 #include <asm/proto.h>
  18 #include <asm/cpumask.h>
  19 #include <asm/cpu.h>
  20 #include <asm/stackprotector.h>
  21
  22 #ifdef CONFIG_DEBUG_PER_CPU_MAPS
  23 # define DBG(x...) printk(KERN_DEBUG x)
  24 #else
  25 # define DBG(x...)
  26 #endif
  27
  28 DEFINE_PER_CPU(int, cpu_number);
  29 EXPORT_PER_CPU_SYMBOL(cpu_number);
  30
  31 #ifdef CONFIG_X86_64
  32 #define BOOT_PERCPU_OFFSET ((unsigned long)__per_cpu_load)
  33 #else
  34 #define BOOT_PERCPU_OFFSET 0
  35 #endif
  36
  37 DEFINE_PER_CPU(unsigned long, this_cpu_off) = BOOT_PERCPU_OFFSET;
  38 EXPORT_PER_CPU_SYMBOL(this_cpu_off);
  39
  40 unsigned long __per_cpu_offset[NR_CPUS] __read_mostly = {
  41         [0 ... NR_CPUS-1] = BOOT_PERCPU_OFFSET,
  42 };
  43 EXPORT_SYMBOL(__per_cpu_offset);
  44
  45 /*
  46  * On x86_64 symbols referenced from code should be reachable using
  47  * 32bit relocations.  Reserve space for static percpu variables in
  48  * modules so that they are always served from the first chunk which
  49  * is located at the percpu segment base.  On x86_32, anything can
  50  * address anywhere.  No need to reserve space in the first chunk.
  51  */
  52 #ifdef CONFIG_X86_64
  53 #define PERCPU_FIRST_CHUNK_RESERVE      PERCPU_MODULE_RESERVE
  54 #else
  55 #define PERCPU_FIRST_CHUNK_RESERVE      0
  56 #endif
  57
  58 #ifdef CONFIG_X86_32
  59 /**
  60  * pcpu_need_numa - determine percpu allocation needs to consider NUMA
  61  *
  62  * If NUMA is not configured or there is only one NUMA node available,
  63  * there is no reason to consider NUMA.  This function determines
  64  * whether percpu allocation should consider NUMA or not.
  65  *
  66  * RETURNS:
  67  * true if NUMA should be considered; otherwise, false.
  68  */
  69 static bool __init pcpu_need_numa(void)
  70 {
  71 #ifdef CONFIG_NEED_MULTIPLE_NODES
  72         pg_data_t *last = NULL;
  73         unsigned int cpu;
  74
  75         for_each_possible_cpu(cpu) {
  76                 int node = early_cpu_to_node(cpu);
  77
  78                 if (node_online(node) && NODE_DATA(node) &&
  79                     last && last != NODE_DATA(node))
  80                         return true;
  81
  82                 last = NODE_DATA(node);
  83         }
  84 #endif
  85         return false;
  86 }
  87 #endif
  88
  89 /**
  90  * pcpu_alloc_bootmem - NUMA friendly alloc_bootmem wrapper for percpu
  91  * @cpu: cpu to allocate for
  92  * @size: size allocation in bytes
  93  * @align: alignment
  94  *
  95  * Allocate @size bytes aligned at @align for cpu @cpu.  This wrapper
  96  * does the right thing for NUMA regardless of the current
  97  * configuration.
  98  *
  99  * RETURNS:
 100  * Pointer to the allocated area on success, NULL on failure.
 101  */
 102 static void * __init pcpu_alloc_bootmem(unsigned int cpu, unsigned long size,
 103                                         unsigned long align)
 104 {
 105         const unsigned long goal = __pa(MAX_DMA_ADDRESS);
 106 #ifdef CONFIG_NEED_MULTIPLE_NODES
 107         int node = early_cpu_to_node(cpu);
 108         void *ptr;
 109
 110         if (!node_online(node) || !NODE_DATA(node)) {
 111                 ptr = __alloc_bootmem_nopanic(size, align, goal);
 112                 pr_info("cpu %d has no node %d or node-local memory\n",
 113                         cpu, node);
 114                 pr_debug("per cpu data for cpu%d %lu bytes at %016lx\n",
 115                          cpu, size, __pa(ptr));
 116         } else {
 117                 ptr = __alloc_bootmem_node_nopanic(NODE_DATA(node),
 118                                                    size, align, goal);
 119                 pr_debug("per cpu data for cpu%d %lu bytes on node%d at "
 120                          "%016lx\n", cpu, size, node, __pa(ptr));
 121         }
 122         return ptr;
 123 #else
 124         return __alloc_bootmem_nopanic(size, align, goal);
 125 #endif
 126 }
 127
 128 /*
 129  * Helpers for first chunk memory allocation
 130  */
 131 static 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
 136 static void __init pcpu_fc_free(void *ptr, size_t size)
 137 {
 138         free_bootmem(__pa(ptr), size);
 139 }
 140
 141 static 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
 153 static void __init pcpup_populate_pte(unsigned long addr)
 154 {
 155         populate_extra_pte(addr);
 156 }
 157
 158 static inline void setup_percpu_segment(int cpu)
 159 {
 160 #ifdef CONFIG_X86_32
 161         struct desc_struct gdt;
 162
 163         pack_descriptor(&gdt, per_cpu_offset(cpu), 0xFFFFF,
 164                         0x2 | DESCTYPE_S, 0x8);
 165         gdt.s = 1;
 166         write_gdt_entry(get_cpu_gdt_table(cpu),
 167                         GDT_ENTRY_PERCPU, &gdt, DESCTYPE_S);
 168 #endif
 169 }
 170
 171 void __init setup_per_cpu_areas(void)
 172 {
 173         unsigned int cpu;
 174         unsigned long delta;
 175         int rc;
 176
 177         pr_info("NR_CPUS:%d nr_cpumask_bits:%d nr_cpu_ids:%d nr_node_ids:%d\n",
 178                 NR_CPUS, nr_cpumask_bits, nr_cpu_ids, nr_node_ids);
 179
 180         /*
 181          * Allocate percpu area.  Embedding allocator is our favorite;
 182          * however, on NUMA configurations, it can result in very
 183          * sparse unit mapping and vmalloc area isn't spacious enough
 184          * on 32bit.  Use page in that case.
 185          */
 186 #ifdef CONFIG_X86_32
 187         if (pcpu_chosen_fc == PCPU_FC_AUTO && pcpu_need_numa())
 188                 pcpu_chosen_fc = PCPU_FC_PAGE;
 189 #endif
 190         rc = -EINVAL;
 191         if (pcpu_chosen_fc != PCPU_FC_PAGE) {
 192                 const size_t atom_size = cpu_has_pse ? PMD_SIZE : PAGE_SIZE;
 193                 const size_t dyn_size = PERCPU_MODULE_RESERVE +
 194                         PERCPU_DYNAMIC_RESERVE - PERCPU_FIRST_CHUNK_RESERVE;
 195
 196                 rc = pcpu_embed_first_chunk(PERCPU_FIRST_CHUNK_RESERVE,
 197                                             dyn_size, atom_size,
 198                                             pcpu_cpu_distance,
 199                                             pcpu_fc_alloc, pcpu_fc_free);
 200                 if (rc < 0)
 201                         pr_warning("PERCPU: %s allocator failed (%d), "
 202                                    "falling back to page size\n",
 203                                    pcpu_fc_names[pcpu_chosen_fc], rc);
 204         }
 205         if (rc < 0)
 206                 rc = pcpu_page_first_chunk(PERCPU_FIRST_CHUNK_RESERVE,
 207                                            pcpu_fc_alloc, pcpu_fc_free,
 208                                            pcpup_populate_pte);
 209         if (rc < 0)
 210                 panic("cannot initialize percpu area (err=%d)", rc);
 211
 212         /* alrighty, percpu areas up and running */
 213         delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
 214         for_each_possible_cpu(cpu) {
 215                 per_cpu_offset(cpu) = delta + pcpu_unit_offsets[cpu];
 216                 per_cpu(this_cpu_off, cpu) = per_cpu_offset(cpu);
 217                 per_cpu(cpu_number, cpu) = cpu;
 218                 setup_percpu_segment(cpu);
 219                 setup_stack_canary_segment(cpu);
 220                 /*
 221                  * Copy data used in early init routines from the
 222                  * initial arrays to the per cpu data areas.  These
 223                  * arrays then become expendable and the *_early_ptr's
 224                  * are zeroed indicating that the static arrays are
 225                  * gone.
 226                  */
 227 #ifdef CONFIG_X86_LOCAL_APIC
 228                 per_cpu(x86_cpu_to_apicid, cpu) =
 229                         early_per_cpu_map(x86_cpu_to_apicid, cpu);
 230                 per_cpu(x86_bios_cpu_apicid, cpu) =
 231                         early_per_cpu_map(x86_bios_cpu_apicid, cpu);
 232 #endif
 233 #ifdef CONFIG_X86_64
 234                 per_cpu(irq_stack_ptr, cpu) =
 235                         per_cpu(irq_stack_union.irq_stack, cpu) +
 236                         IRQ_STACK_SIZE - 64;
 237 #ifdef CONFIG_NUMA
 238                 per_cpu(x86_cpu_to_node_map, cpu) =
 239                         early_per_cpu_map(x86_cpu_to_node_map, cpu);
 240 #endif
 241 #endif
 242                 /*
 243                  * Up to this point, the boot CPU has been using .data.init
 244                  * area.  Reload any changed state for the boot CPU.
 245                  */
 246                 if (cpu == boot_cpu_id)
 247                         switch_to_new_gdt(cpu);
 248         }
 249
 250         /* indicate the early static arrays will soon be gone */
 251 #ifdef CONFIG_X86_LOCAL_APIC
 252         early_per_cpu_ptr(x86_cpu_to_apicid) = NULL;
 253         early_per_cpu_ptr(x86_bios_cpu_apicid) = NULL;
 254 #endif
 255 #if defined(CONFIG_X86_64) && defined(CONFIG_NUMA)
 256         early_per_cpu_ptr(x86_cpu_to_node_map) = NULL;
 257 #endif
 258
 259 #if defined(CONFIG_X86_64) && defined(CONFIG_NUMA)
 260         /*
 261          * make sure boot cpu node_number is right, when boot cpu is on the
 262          * node that doesn't have mem installed
 263          */
 264         per_cpu(node_number, boot_cpu_id) = cpu_to_node(boot_cpu_id);
 265 #endif
 266
 267         /* Setup node to cpumask map */
 268         setup_node_to_cpumask_map();
 269
 270         /* Setup cpu initialized, callin, callout masks */
 271         setup_cpu_local_masks();
 272 }