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