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(int, x2apic_extra_bits);
  35
  36 struct genapic __read_mostly *genapic = &apic_flat;
  37
  38 static enum uv_system_type uv_system_type;
  39
  40 /*
  41  * Check the APIC IDs in bios_cpu_apicid and choose the APIC mode.
  42  */
  43 void __init setup_apic_routing(void)
  44 {
  45         if (uv_system_type == UV_NON_UNIQUE_APIC)
  46                 genapic = &apic_x2apic_uv_x;
  47         else
  48 #ifdef CONFIG_ACPI
  49         /*
  50          * Quirk: some x86_64 machines can only use physical APIC mode
  51          * regardless of how many processors are present (x86_64 ES7000
  52          * is an example).
  53          */
  54         if (acpi_gbl_FADT.header.revision > FADT2_REVISION_ID &&
  55                         (acpi_gbl_FADT.flags & ACPI_FADT_APIC_PHYSICAL))
  56                 genapic = &apic_physflat;
  57         else
  58 #endif
  59
  60         if (cpus_weight(cpu_possible_map) <= 8)
  61                 genapic = &apic_flat;
  62         else
  63                 genapic = &apic_physflat;
  64
  65         printk(KERN_INFO "Setting APIC routing to %s\n", genapic->name);
  66 }
  67
  68 /* Same for both flat and physical. */
  69
  70 void send_IPI_self(int vector)
  71 {
  72         __send_IPI_shortcut(APIC_DEST_SELF, vector, APIC_DEST_PHYSICAL);
  73 }
  74
  75 int __init acpi_madt_oem_check(char *oem_id, char *oem_table_id)
  76 {
  77         if (!strcmp(oem_id, "SGI")) {
  78                 if (!strcmp(oem_table_id, "UVL"))
  79                         uv_system_type = UV_LEGACY_APIC;
  80                 else if (!strcmp(oem_table_id, "UVX"))
  81                         uv_system_type = UV_X2APIC;
  82                 else if (!strcmp(oem_table_id, "UVH"))
  83                         uv_system_type = UV_NON_UNIQUE_APIC;
  84         }
  85         return 0;
  86 }
  87
  88 unsigned int read_apic_id(void)
  89 {
  90         unsigned int id;
  91
  92         WARN_ON(preemptible());
  93         id = apic_read(APIC_ID);
  94         if (uv_system_type >= UV_X2APIC)
  95                 id  |= __get_cpu_var(x2apic_extra_bits);
  96         return id;
  97 }
  98
  99 enum uv_system_type get_uv_system_type(void)
 100 {
 101         return uv_system_type;
 102 }
 103
 104 int is_uv_system(void)
 105 {
 106         return uv_system_type != UV_NONE;
 107 }