linux/arch/x86/kernel/genapic_64.c
Mike Travis 71fff5e6ca x86: convert cpu_to_apicid to be a per cpu variable
This patch converts the x86_cpu_to_apicid array to be a per cpu
variable. This saves sizeof(apicid) * NR unused cpus.  Access is mostly
from startup and CPU HOTPLUG functions.

MP_processor_info() is one of the functions that require access to the
x86_cpu_to_apicid array before the per_cpu data area is setup.  For this
case, a pointer to the __initdata array is initialized in setup_arch()
and removed in smp_prepare_cpus() after the per_cpu data area is
initialized.

A second change is included to change the initial array value of ARCH
i386 from 0xff to BAD_APICID to be consistent with ARCH x86_64.

Signed-off-by: Mike Travis <travis@sgi.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: "Siddha, Suresh B" <suresh.b.siddha@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2007-10-19 20:35:03 +02:00

74 lines
1.8 KiB
C

/*
* Copyright 2004 James Cleverdon, IBM.
* Subject to the GNU Public License, v.2
*
* Generic APIC sub-arch probe layer.
*
* Hacked for x86-64 by James Cleverdon from i386 architecture code by
* Martin Bligh, Andi Kleen, James Bottomley, John Stultz, and
* James Cleverdon.
*/
#include <linux/threads.h>
#include <linux/cpumask.h>
#include <linux/string.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/ctype.h>
#include <linux/init.h>
#include <asm/smp.h>
#include <asm/ipi.h>
#include <asm/genapic.h>
#ifdef CONFIG_ACPI
#include <acpi/acpi_bus.h>
#endif
/*
* which logical CPU number maps to which CPU (physical APIC ID)
*
* The following static array is used during kernel startup
* and the x86_cpu_to_apicid_ptr contains the address of the
* array during this time. Is it zeroed when the per_cpu
* data area is removed.
*/
u8 x86_cpu_to_apicid_init[NR_CPUS] __initdata
= { [0 ... NR_CPUS-1] = BAD_APICID };
void *x86_cpu_to_apicid_ptr;
DEFINE_PER_CPU(u8, x86_cpu_to_apicid) = BAD_APICID;
EXPORT_PER_CPU_SYMBOL(x86_cpu_to_apicid);
struct genapic __read_mostly *genapic = &apic_flat;
/*
* Check the APIC IDs in bios_cpu_apicid and choose the APIC mode.
*/
void __init setup_apic_routing(void)
{
#ifdef CONFIG_ACPI
/*
* Quirk: some x86_64 machines can only use physical APIC mode
* regardless of how many processors are present (x86_64 ES7000
* is an example).
*/
if (acpi_gbl_FADT.header.revision > FADT2_REVISION_ID &&
(acpi_gbl_FADT.flags & ACPI_FADT_APIC_PHYSICAL))
genapic = &apic_physflat;
else
#endif
if (cpus_weight(cpu_possible_map) <= 8)
genapic = &apic_flat;
else
genapic = &apic_physflat;
printk(KERN_INFO "Setting APIC routing to %s\n", genapic->name);
}
/* Same for both flat and physical. */
void send_IPI_self(int vector)
{
__send_IPI_shortcut(APIC_DEST_SELF, vector, APIC_DEST_PHYSICAL);
}