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
  19 #include <asm/smp.h>
  20 #include <asm/ipi.h>
  21 #include <asm/genapic.h>
  22
  23 #ifdef CONFIG_ACPI
  24 #include <acpi/acpi_bus.h>
  25 #endif
  26
  27 /*
  28  * which logical CPU number maps to which CPU (physical APIC ID)
  29  *
  30  * The following static array is used during kernel startup
  31  * and the x86_cpu_to_apicid_ptr contains the address of the
  32  * array during this time.  Is it zeroed when the per_cpu
  33  * data area is removed.
  34  */
  35 u8 x86_cpu_to_apicid_init[NR_CPUS] __initdata
  36                                         = { [0 ... NR_CPUS-1] = BAD_APICID };
  37 void *x86_cpu_to_apicid_ptr;
  38 DEFINE_PER_CPU(u8, x86_cpu_to_apicid) = BAD_APICID;
  39 EXPORT_PER_CPU_SYMBOL(x86_cpu_to_apicid);
  40
  41 struct genapic __read_mostly *genapic = &apic_flat;
  42
  43 /*
  44  * Check the APIC IDs in bios_cpu_apicid and choose the APIC mode.
  45  */
  46 void __init setup_apic_routing(void)
  47 {
  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 }