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
  19 #ifdef CONFIG_DEBUG_PER_CPU_MAPS
  20 # define DBG(x...) printk(KERN_DEBUG x)
  21 #else
  22 # define DBG(x...)
  23 #endif
  24
  25 DEFINE_PER_CPU(int, cpu_number);
  26 EXPORT_PER_CPU_SYMBOL(cpu_number);
  27
  28 #ifdef CONFIG_X86_64
  29 #define BOOT_PERCPU_OFFSET ((unsigned long)__per_cpu_load)
  30 #else
  31 #define BOOT_PERCPU_OFFSET 0
  32 #endif
  33
  34 DEFINE_PER_CPU(unsigned long, this_cpu_off) = BOOT_PERCPU_OFFSET;
  35 EXPORT_PER_CPU_SYMBOL(this_cpu_off);
  36
  37 #ifdef CONFIG_HAVE_SETUP_PER_CPU_AREA
  38
  39 unsigned long __per_cpu_offset[NR_CPUS] __read_mostly = {
  40         [0] = BOOT_PERCPU_OFFSET,
  41 };
  42 EXPORT_SYMBOL(__per_cpu_offset);
  43
  44 /*
  45  * Great future plan:
  46  * Declare PDA itself and support (irqstack,tss,pgd) as per cpu data.
  47  * Always point %gs to its beginning
  48  */
  49 void __init setup_per_cpu_areas(void)
  50 {
  51         ssize_t size;
  52         char *ptr;
  53         int cpu;
  54
  55         /* Copy section for each CPU (we discard the original) */
  56         size = roundup(PERCPU_ENOUGH_ROOM, PAGE_SIZE);
  57
  58         pr_info("NR_CPUS:%d nr_cpumask_bits:%d nr_cpu_ids:%d nr_node_ids:%d\n",
  59                 NR_CPUS, nr_cpumask_bits, nr_cpu_ids, nr_node_ids);
  60
  61         pr_info("PERCPU: Allocating %zd bytes of per cpu data\n", size);
  62
  63         for_each_possible_cpu(cpu) {
  64 #ifndef CONFIG_NEED_MULTIPLE_NODES
  65                 ptr = alloc_bootmem_pages(size);
  66 #else
  67                 int node = early_cpu_to_node(cpu);
  68                 if (!node_online(node) || !NODE_DATA(node)) {
  69                         ptr = alloc_bootmem_pages(size);
  70                         pr_info("cpu %d has no node %d or node-local memory\n",
  71                                 cpu, node);
  72                         pr_debug("per cpu data for cpu%d at %016lx\n",
  73                                  cpu, __pa(ptr));
  74                 } else {
  75                         ptr = alloc_bootmem_pages_node(NODE_DATA(node), size);
  76                         pr_debug("per cpu data for cpu%d on node%d at %016lx\n",
  77                                 cpu, node, __pa(ptr));
  78                 }
  79 #endif
  80
  81                 memcpy(ptr, __per_cpu_load, __per_cpu_end - __per_cpu_start);
  82                 per_cpu_offset(cpu) = ptr - __per_cpu_start;
  83                 per_cpu(this_cpu_off, cpu) = per_cpu_offset(cpu);
  84                 per_cpu(cpu_number, cpu) = cpu;
  85                 /*
  86                  * Copy data used in early init routines from the initial arrays to the
  87                  * per cpu data areas.  These arrays then become expendable and the
  88                  * *_early_ptr's are zeroed indicating that the static arrays are gone.
  89                  */
  90 #ifdef CONFIG_X86_LOCAL_APIC
  91                 per_cpu(x86_cpu_to_apicid, cpu) =
  92                                 early_per_cpu_map(x86_cpu_to_apicid, cpu);
  93                 per_cpu(x86_bios_cpu_apicid, cpu) =
  94                                 early_per_cpu_map(x86_bios_cpu_apicid, cpu);
  95 #endif
  96 #ifdef CONFIG_X86_64
  97                 per_cpu(irq_stack_ptr, cpu) =
  98                         per_cpu(irq_stack_union.irq_stack, cpu) + IRQ_STACK_SIZE - 64;
  99 #ifdef CONFIG_NUMA
 100                 per_cpu(x86_cpu_to_node_map, cpu) =
 101                                 early_per_cpu_map(x86_cpu_to_node_map, cpu);
 102 #endif
 103                 /*
 104                  * Up to this point, CPU0 has been using .data.init
 105                  * area.  Reload %gs offset for CPU0.
 106                  */
 107                 if (cpu == 0)
 108                         load_gs_base(cpu);
 109 #endif
 110
 111                 DBG("PERCPU: cpu %4d %p\n", cpu, ptr);
 112         }
 113
 114         /* indicate the early static arrays will soon be gone */
 115         early_per_cpu_ptr(x86_cpu_to_apicid) = NULL;
 116         early_per_cpu_ptr(x86_bios_cpu_apicid) = NULL;
 117 #if defined(CONFIG_X86_64) && defined(CONFIG_NUMA)
 118         early_per_cpu_ptr(x86_cpu_to_node_map) = NULL;
 119 #endif
 120
 121         /* Setup node to cpumask map */
 122         setup_node_to_cpumask_map();
 123
 124         /* Setup cpu initialized, callin, callout masks */
 125         setup_cpu_local_masks();
 126 }
 127
 128 #endif
 129