linux/arch/x86/kernel/apic/probe_64.c
Suresh Siddha 2fbd07a5f5 x86, apic: Use logical flat on intel with <= 8 logical cpus
On Intel platforms, we can use logical flat mode if there are <= 8
logical cpu's (irrespective of physical apic id values). This will
enable simplified and efficient IPI and device interrupt routing on
such platforms.

Fix the relevant comments while we are at it.

We can clean up default_setup_apic_routing() by using apic->probe()
but that is a different item.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: "yinghai@kernel.org" <yinghai@kernel.org>
LKML-Reference: <1253327399.3948.747.camel@sbs-t61.sc.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-19 09:20:05 +02:00

118 lines
2.5 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 <linux/hardirq.h>
#include <linux/dmar.h>
#include <asm/smp.h>
#include <asm/apic.h>
#include <asm/ipi.h>
#include <asm/setup.h>
extern struct apic apic_flat;
extern struct apic apic_physflat;
extern struct apic apic_x2xpic_uv_x;
extern struct apic apic_x2apic_phys;
extern struct apic apic_x2apic_cluster;
struct apic __read_mostly *apic = &apic_flat;
EXPORT_SYMBOL_GPL(apic);
static struct apic *apic_probe[] __initdata = {
#ifdef CONFIG_X86_UV
&apic_x2apic_uv_x,
#endif
#ifdef CONFIG_X86_X2APIC
&apic_x2apic_phys,
&apic_x2apic_cluster,
#endif
&apic_physflat,
NULL,
};
static int apicid_phys_pkg_id(int initial_apic_id, int index_msb)
{
return hard_smp_processor_id() >> index_msb;
}
/*
* Check the APIC IDs in bios_cpu_apicid and choose the APIC mode.
*/
void __init default_setup_apic_routing(void)
{
#ifdef CONFIG_X86_X2APIC
if (x2apic_mode
#ifdef CONFIG_X86_UV
&& apic != &apic_x2apic_uv_x
#endif
) {
if (x2apic_phys)
apic = &apic_x2apic_phys;
else
apic = &apic_x2apic_cluster;
}
#endif
if (apic == &apic_flat) {
switch (boot_cpu_data.x86_vendor) {
case X86_VENDOR_INTEL:
if (num_processors > 8)
apic = &apic_physflat;
break;
case X86_VENDOR_AMD:
if (max_physical_apicid >= 8)
apic = &apic_physflat;
}
}
printk(KERN_INFO "Setting APIC routing to %s\n", apic->name);
if (is_vsmp_box()) {
/* need to update phys_pkg_id */
apic->phys_pkg_id = apicid_phys_pkg_id;
}
/*
* Now that apic routing model is selected, configure the
* fault handling for intr remapping.
*/
if (intr_remapping_enabled)
enable_drhd_fault_handling();
}
/* Same for both flat and physical. */
void apic_send_IPI_self(int vector)
{
__default_send_IPI_shortcut(APIC_DEST_SELF, vector, APIC_DEST_PHYSICAL);
}
int __init default_acpi_madt_oem_check(char *oem_id, char *oem_table_id)
{
int i;
for (i = 0; apic_probe[i]; ++i) {
if (apic_probe[i]->acpi_madt_oem_check(oem_id, oem_table_id)) {
apic = apic_probe[i];
printk(KERN_INFO "Setting APIC routing to %s.\n",
apic->name);
return 1;
}
}
return 0;
}