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 <asm/sections.h>
  11 #include <asm/processor.h>
  12 #include <asm/setup.h>
  13 #include <asm/mpspec.h>
  14 #include <asm/apicdef.h>
  15 #include <asm/highmem.h>
  16 #include <asm/proto.h>
  17 #include <asm/cpumask.h>
  18 #include <asm/cpu.h>
  19 #include <asm/stackprotector.h>
  20
  21 #ifdef CONFIG_DEBUG_PER_CPU_MAPS
  22 # define DBG(x...) printk(KERN_DEBUG x)
  23 #else
  24 # define DBG(x...)
  25 #endif
  26
  27 DEFINE_PER_CPU(int, cpu_number);
  28 EXPORT_PER_CPU_SYMBOL(cpu_number);
  29
  30 #ifdef CONFIG_X86_64
  31 #define BOOT_PERCPU_OFFSET ((unsigned long)__per_cpu_load)
  32 #else
  33 #define BOOT_PERCPU_OFFSET 0
  34 #endif
  35
  36 DEFINE_PER_CPU(unsigned long, this_cpu_off) = BOOT_PERCPU_OFFSET;
  37 EXPORT_PER_CPU_SYMBOL(this_cpu_off);
  38
  39 unsigned long __per_cpu_offset[NR_CPUS] __read_mostly = {
  40         [0 ... NR_CPUS-1] = BOOT_PERCPU_OFFSET,
  41 };
  42 EXPORT_SYMBOL(__per_cpu_offset);
  43
  44 static inline void setup_percpu_segment(int cpu)
  45 {
  46 #ifdef CONFIG_X86_32
  47         struct desc_struct gdt;
  48
  49         pack_descriptor(&gdt, per_cpu_offset(cpu), 0xFFFFF,
  50                         0x2 | DESCTYPE_S, 0x8);
  51         gdt.s = 1;
  52         write_gdt_entry(get_cpu_gdt_table(cpu),
  53                         GDT_ENTRY_PERCPU, &gdt, DESCTYPE_S);
  54 #endif
  55 }
  56
  57 /*
  58  * Great future plan:
  59  * Declare PDA itself and support (irqstack,tss,pgd) as per cpu data.
  60  * Always point %gs to its beginning
  61  */
  62 void __init setup_per_cpu_areas(void)
  63 {
  64         ssize_t size;
  65         char *ptr;
  66         int cpu;
  67
  68         /* Copy section for each CPU (we discard the original) */
  69         size = roundup(PERCPU_ENOUGH_ROOM, PAGE_SIZE);
  70
  71         pr_info("NR_CPUS:%d nr_cpumask_bits:%d nr_cpu_ids:%d nr_node_ids:%d\n",
  72                 NR_CPUS, nr_cpumask_bits, nr_cpu_ids, nr_node_ids);
  73
  74         pr_info("PERCPU: Allocating %zd bytes of per cpu data\n", size);
  75
  76         for_each_possible_cpu(cpu) {
  77 #ifndef CONFIG_NEED_MULTIPLE_NODES
  78                 ptr = alloc_bootmem_pages(size);
  79 #else
  80                 int node = early_cpu_to_node(cpu);
  81                 if (!node_online(node) || !NODE_DATA(node)) {
  82                         ptr = alloc_bootmem_pages(size);
  83                         pr_info("cpu %d has no node %d or node-local memory\n",
  84                                 cpu, node);
  85                         pr_debug("per cpu data for cpu%d at %016lx\n",
  86                                  cpu, __pa(ptr));
  87                 } else {
  88                         ptr = alloc_bootmem_pages_node(NODE_DATA(node), size);
  89                         pr_debug("per cpu data for cpu%d on node%d at %016lx\n",
  90                                 cpu, node, __pa(ptr));
  91                 }
  92 #endif
  93
  94                 memcpy(ptr, __per_cpu_load, __per_cpu_end - __per_cpu_start);
  95                 per_cpu_offset(cpu) = ptr - __per_cpu_start;
  96                 per_cpu(this_cpu_off, cpu) = per_cpu_offset(cpu);
  97                 per_cpu(cpu_number, cpu) = cpu;
  98                 setup_percpu_segment(cpu);
  99                 setup_stack_canary_segment(cpu);
 100                 /*
 101                  * Copy data used in early init routines from the
 102                  * initial arrays to the per cpu data areas.  These
 103                  * arrays then become expendable and the *_early_ptr's
 104                  * are zeroed indicating that the static arrays are
 105                  * gone.
 106                  */
 107 #ifdef CONFIG_X86_LOCAL_APIC
 108                 per_cpu(x86_cpu_to_apicid, cpu) =
 109                         early_per_cpu_map(x86_cpu_to_apicid, cpu);
 110                 per_cpu(x86_bios_cpu_apicid, cpu) =
 111                         early_per_cpu_map(x86_bios_cpu_apicid, cpu);
 112 #endif
 113 #ifdef CONFIG_X86_64
 114                 per_cpu(irq_stack_ptr, cpu) =
 115                         per_cpu(irq_stack_union.irq_stack, cpu) +
 116                         IRQ_STACK_SIZE - 64;
 117 #ifdef CONFIG_NUMA
 118                 per_cpu(x86_cpu_to_node_map, cpu) =
 119                         early_per_cpu_map(x86_cpu_to_node_map, cpu);
 120 #endif
 121 #endif
 122                 /*
 123                  * Up to this point, the boot CPU has been using .data.init
 124                  * area.  Reload any changed state for the boot CPU.
 125                  */
 126                 if (cpu == boot_cpu_id)
 127                         switch_to_new_gdt(cpu);
 128
 129                 DBG("PERCPU: cpu %4d %p\n", cpu, ptr);
 130         }
 131
 132         /* indicate the early static arrays will soon be gone */
 133 #ifdef CONFIG_X86_LOCAL_APIC
 134         early_per_cpu_ptr(x86_cpu_to_apicid) = NULL;
 135         early_per_cpu_ptr(x86_bios_cpu_apicid) = NULL;
 136 #endif
 137 #if defined(CONFIG_X86_64) && defined(CONFIG_NUMA)
 138         early_per_cpu_ptr(x86_cpu_to_node_map) = NULL;
 139 #endif
 140
 141         /* Setup node to cpumask map */
 142         setup_node_to_cpumask_map();
 143
 144         /* Setup cpu initialized, callin, callout masks */
 145         setup_cpu_local_masks();
 146 }