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 /*
  44  * Great future plan:
  45  * Declare PDA itself and support (irqstack,tss,pgd) as per cpu data.
  46  * Always point %gs to its beginning
  47  */
  48 void __init setup_per_cpu_areas(void)
  49 {
  50         ssize_t size;
  51         char *ptr;
  52         int cpu;
  53
  54         /* Copy section for each CPU (we discard the original) */
  55         size = roundup(PERCPU_ENOUGH_ROOM, PAGE_SIZE);
  56
  57         pr_info("NR_CPUS:%d nr_cpumask_bits:%d nr_cpu_ids:%d nr_node_ids:%d\n",
  58                 NR_CPUS, nr_cpumask_bits, nr_cpu_ids, nr_node_ids);
  59
  60         pr_info("PERCPU: Allocating %zd bytes of per cpu data\n", size);
  61
  62         for_each_possible_cpu(cpu) {
  63 #ifndef CONFIG_NEED_MULTIPLE_NODES
  64                 ptr = alloc_bootmem_pages(size);
  65 #else
  66                 int node = early_cpu_to_node(cpu);
  67                 if (!node_online(node) || !NODE_DATA(node)) {
  68                         ptr = alloc_bootmem_pages(size);
  69                         pr_info("cpu %d has no node %d or node-local memory\n",
  70                                 cpu, node);
  71                         pr_debug("per cpu data for cpu%d at %016lx\n",
  72                                  cpu, __pa(ptr));
  73                 } else {
  74                         ptr = alloc_bootmem_pages_node(NODE_DATA(node), size);
  75                         pr_debug("per cpu data for cpu%d on node%d at %016lx\n",
  76                                 cpu, node, __pa(ptr));
  77                 }
  78 #endif
  79
  80                 memcpy(ptr, __per_cpu_load, __per_cpu_end - __per_cpu_start);
  81                 per_cpu_offset(cpu) = ptr - __per_cpu_start;
  82                 per_cpu(this_cpu_off, cpu) = per_cpu_offset(cpu);
  83                 per_cpu(cpu_number, cpu) = cpu;
  84                 /*
  85                  * Copy data used in early init routines from the initial arrays to the
  86                  * per cpu data areas.  These arrays then become expendable and the
  87                  * *_early_ptr's are zeroed indicating that the static arrays are gone.
  88                  */
  89 #ifdef CONFIG_X86_LOCAL_APIC
  90                 per_cpu(x86_cpu_to_apicid, cpu) =
  91                                 early_per_cpu_map(x86_cpu_to_apicid, cpu);
  92                 per_cpu(x86_bios_cpu_apicid, cpu) =
  93                                 early_per_cpu_map(x86_bios_cpu_apicid, cpu);
  94 #endif
  95 #ifdef CONFIG_X86_64
  96                 per_cpu(irq_stack_ptr, cpu) =
  97                         per_cpu(irq_stack_union.irq_stack, cpu) + IRQ_STACK_SIZE - 64;
  98 #ifdef CONFIG_NUMA
  99                 per_cpu(x86_cpu_to_node_map, cpu) =
 100                                 early_per_cpu_map(x86_cpu_to_node_map, cpu);
 101 #endif
 102                 /*
 103                  * Up to this point, the boot CPU has been using .data.init
 104                  * area.  Reload %gs offset for the boot CPU.
 105                  */
 106                 if (cpu == boot_cpu_id)
 107                         load_gs_base(cpu);
 108 #endif
 109
 110                 DBG("PERCPU: cpu %4d %p\n", cpu, ptr);
 111         }
 112
 113         /* indicate the early static arrays will soon be gone */
 114         early_per_cpu_ptr(x86_cpu_to_apicid) = NULL;
 115         early_per_cpu_ptr(x86_bios_cpu_apicid) = NULL;
 116 #if defined(CONFIG_X86_64) && defined(CONFIG_NUMA)
 117         early_per_cpu_ptr(x86_cpu_to_node_map) = NULL;
 118 #endif
 119
 120         /* Setup node to cpumask map */
 121         setup_node_to_cpumask_map();
 122
 123         /* Setup cpu initialized, callin, callout masks */
 124         setup_cpu_local_masks();
 125 }