linux/arch/x86/kernel/genapic_64.c
Jack Steiner ac23d4ee3f x86: support for new UV apic
UV supports really big systems. So big, in fact, that the APICID register
does not contain enough bits to contain an APICID that is unique across all
cpus.

The UV BIOS supports 3 APICID modes:

	- legacy mode. This mode uses the old APIC mode where
	  APICID is in bits [31:24] of the APICID register.

	- x2apic mode. This mode is whitebox-compatible. APICIDs
	  are unique across all cpus. Standard x2apic APIC operations
	  (Intel-defined) can be used for IPIs. The node identifier
	  fits within the Intel-defined portion of the APICID register.

	- x2apic-uv mode. In this mode, the APICIDs on each node have
	  unique IDs, but IDs on different node are not unique. For example,
	  if each mode has 32 cpus, the APICIDs on each node might be
	  0 - 31. Every node has the same set of IDs.
	  The UV hub is used to route IPIs/interrupts to the correct node.
	  Traditional APIC operations WILL NOT WORK.

In x2apic-uv mode, the ACPI tables all contain a full unique ID (note:
exact bit layout still changing but the following is close):

	nnnnnnnnnnlc0cch
		n = unique node number
		l = socket number on board
		c = core
		h = hyperthread

Only the "lc0cch" bits are written to the APICID register. The remaining bits are
supplied by having the get_apic_id() function "OR" the extra bits into the value
read from the APICID register. (Hmmm.. why not keep the ENTIRE APICID register
in per-cpu data....)

The x2apic-uv mode is recognized by the MADT table containing:
	  oem_id = "SGI"
	  oem_table_id = "UV-X"

Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17 17:41:33 +02:00

112 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 <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) */
#ifdef CONFIG_SMP
u16 x86_cpu_to_apicid_init[NR_CPUS] __initdata
= { [0 ... NR_CPUS-1] = BAD_APICID };
void *x86_cpu_to_apicid_early_ptr;
#endif
DEFINE_PER_CPU(u16, x86_cpu_to_apicid) = BAD_APICID;
EXPORT_PER_CPU_SYMBOL(x86_cpu_to_apicid);
DEFINE_PER_CPU(int, x2apic_extra_bits);
struct genapic __read_mostly *genapic = &apic_flat;
static enum uv_system_type uv_system_type;
/*
* Check the APIC IDs in bios_cpu_apicid and choose the APIC mode.
*/
void __init setup_apic_routing(void)
{
if (uv_system_type == UV_NON_UNIQUE_APIC)
genapic = &apic_x2apic_uv_x;
else
#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);
}
int __init acpi_madt_oem_check(char *oem_id, char *oem_table_id)
{
if (!strcmp(oem_id, "SGI")) {
if (!strcmp(oem_table_id, "UVL"))
uv_system_type = UV_LEGACY_APIC;
else if (!strcmp(oem_table_id, "UVX"))
uv_system_type = UV_X2APIC;
else if (!strcmp(oem_table_id, "UVH"))
uv_system_type = UV_NON_UNIQUE_APIC;
}
return 0;
}
unsigned int read_apic_id(void)
{
unsigned int id;
WARN_ON(preemptible());
id = apic_read(APIC_ID);
if (uv_system_type >= UV_X2APIC)
id |= __get_cpu_var(x2apic_extra_bits);
else
id = (id >> 24) & 0xFFu;;
return id;
}
enum uv_system_type get_uv_system_type(void)
{
return uv_system_type;
}
int is_uv_system(void)
{
return uv_system_type != UV_NONE;
}