arch/x86/kernel/genapic_64.c

   1 /*
   2  * Copyright 2004 James Cleverdon, IBM.
   3  * Subject to the GNU Public License, v.2
   4  *
   5  * Generic APIC sub-arch probe layer.
   6  *
   7  * Hacked for x86-64 by James Cleverdon from i386 architecture code by
   8  * Martin Bligh, Andi Kleen, James Bottomley, John Stultz, and
   9  * James Cleverdon.
  10  */
  11 #include <linux/threads.h>
  12 #include <linux/cpumask.h>
  13 #include <linux/string.h>
  14 #include <linux/module.h>
  15 #include <linux/kernel.h>
  16 #include <linux/ctype.h>
  17 #include <linux/init.h>
  18 #include <linux/hardirq.h>
  19
  20 #include <asm/smp.h>
  21 #include <asm/ipi.h>
  22 #include <asm/genapic.h>
  23
  24 #ifdef CONFIG_ACPI
  25 #include <acpi/acpi_bus.h>
  26 #endif
  27
  28 /* which logical CPU number maps to which CPU (physical APIC ID) */
  29 #ifdef CONFIG_SMP
  30 u16 x86_cpu_to_apicid_init[NR_CPUS] __initdata
  31                                         = { [0 ... NR_CPUS-1] = BAD_APICID };
  32 void *x86_cpu_to_apicid_early_ptr;
  33 #endif
  34 DEFINE_PER_CPU(u16, x86_cpu_to_apicid) = BAD_APICID;
  35 EXPORT_PER_CPU_SYMBOL(x86_cpu_to_apicid);
  36 DEFINE_PER_CPU(int, x2apic_extra_bits);
  37
  38 struct genapic __read_mostly *genapic = &apic_flat;
  39
  40 static enum uv_system_type uv_system_type;
  41
  42 /*
  43  * Check the APIC IDs in bios_cpu_apicid and choose the APIC mode.
  44  */
  45 void __init setup_apic_routing(void)
  46 {
  47         if (uv_system_type == UV_NON_UNIQUE_APIC)
  48                 genapic = &apic_x2apic_uv_x;
  49         else
  50 #ifdef CONFIG_ACPI
  51         /*
  52          * Quirk: some x86_64 machines can only use physical APIC mode
  53          * regardless of how many processors are present (x86_64 ES7000
  54          * is an example).
  55          */
  56         if (acpi_gbl_FADT.header.revision > FADT2_REVISION_ID &&
  57                         (acpi_gbl_FADT.flags & ACPI_FADT_APIC_PHYSICAL))
  58                 genapic = &apic_physflat;
  59         else
  60 #endif
  61
  62         if (cpus_weight(cpu_possible_map) <= 8)
  63                 genapic = &apic_flat;
  64         else
  65                 genapic = &apic_physflat;
  66
  67         printk(KERN_INFO "Setting APIC routing to %s\n", genapic->name);
  68 }
  69
  70 /* Same for both flat and physical. */
  71
  72 void send_IPI_self(int vector)
  73 {
  74         __send_IPI_shortcut(APIC_DEST_SELF, vector, APIC_DEST_PHYSICAL);
  75 }
  76
  77 int __init acpi_madt_oem_check(char *oem_id, char *oem_table_id)
  78 {
  79         if (!strcmp(oem_id, "SGI")) {
  80                 if (!strcmp(oem_table_id, "UVL"))
  81                         uv_system_type = UV_LEGACY_APIC;
  82                 else if (!strcmp(oem_table_id, "UVX"))
  83                         uv_system_type = UV_X2APIC;
  84                 else if (!strcmp(oem_table_id, "UVH"))
  85                         uv_system_type = UV_NON_UNIQUE_APIC;
  86         }
  87         return 0;
  88 }
  89
  90 unsigned int read_apic_id(void)
  91 {
  92         unsigned int id;
  93
  94         WARN_ON(preemptible());
  95         id = apic_read(APIC_ID);
  96         if (uv_system_type >= UV_X2APIC)
  97                 id  |= __get_cpu_var(x2apic_extra_bits);
  98         else
  99                 id = (id >> 24) & 0xFFu;;
 100         return id;
 101 }
 102
 103 enum uv_system_type get_uv_system_type(void)
 104 {
 105         return uv_system_type;
 106 }
 107
 108 int is_uv_system(void)
 109 {
 110         return uv_system_type != UV_NONE;
 111 }