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linux/arch/x86/kernel/genapic_64.c

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/*
* 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>
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>
2008-03-28 12:12:16 -07:00
#include <linux/hardirq.h>
#include <linux/dmar.h>
#include <asm/smp.h>
#include <asm/ipi.h>
#include <asm/genapic.h>
#include <asm/setup.h>
extern struct genapic apic_flat;
extern struct genapic apic_physflat;
extern struct genapic apic_x2xpic_uv_x;
extern struct genapic apic_x2apic_phys;
extern struct genapic apic_x2apic_cluster;
[PATCH] x86-64: optimize & fix APIC mode setup Fix a couple of inconsistencies/problems I found while reviewing the x86_64 genapic code (when I was chasing mysterious eth0 timeouts that would only trigger if CPU_HOTPLUG is enabled): - AMD systems defaulted to the slower flat-physical mode instead of the flat-logical mode. The only restriction on AMD systems is that they should not use clustered APIC mode. - removed the CPU hotplug hacks, switching the default for small systems back from phys-flat to logical-flat. The switching to logical flat mode on small systems fixed sporadic ethernet driver timeouts i was getting on a dual-core Athlon64 system: NETDEV WATCHDOG: eth0: transmit timed out eth0: Transmit timeout, status 0c 0005 c07f media 80. eth0: Tx queue start entry 32 dirty entry 28. eth0: Tx descriptor 0 is 0008a04a. (queue head) eth0: Tx descriptor 1 is 0008a04a. eth0: Tx descriptor 2 is 0008a04a. eth0: Tx descriptor 3 is 0008a04a. eth0: link up, 100Mbps, full-duplex, lpa 0xC5E1 - The use of '<= 8' was a bug by itself (the valid APIC ids for logical flat mode go from 0 to 7, not 0 to 8). The new logic is to use logical flat mode on both AMD and Intel systems, and to only switch to physical mode when logical mode cannot be used. If CPU hotplug is racy wrt. APIC shutdown then CPU hotplug needs fixing, not the whole IRQ system be made inconsistent and slowed down. - minor cleanups: simplified some code constructs build & booted on a couple of AMD and Intel SMP systems. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Suresh Siddha <suresh.b.siddha@intel.com> Cc: Andi Kleen <ak@suse.de> Cc: "Li, Shaohua" <shaohua.li@intel.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org>
2007-05-02 10:27:04 -07:00
struct genapic __read_mostly *genapic = &apic_flat;
static struct genapic *apic_probe[] __initdata = {
&apic_x2apic_uv_x,
&apic_x2apic_phys,
&apic_x2apic_cluster,
&apic_physflat,
NULL,
};
/*
* Check the APIC IDs in bios_cpu_apicid and choose the APIC mode.
*/
void __init setup_apic_routing(void)
{
if (genapic == &apic_x2apic_phys || genapic == &apic_x2apic_cluster) {
if (!intr_remapping_enabled)
genapic = &apic_flat;
}
if (genapic == &apic_flat) {
if (max_physical_apicid >= 8)
genapic = &apic_physflat;
printk(KERN_INFO "Setting APIC routing to %s\n", genapic->name);
}
if (x86_quirks->update_genapic)
x86_quirks->update_genapic();
}
/* Same for both flat and physical. */
void apic_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)
{
int i;
for (i = 0; apic_probe[i]; ++i) {
if (apic_probe[i]->acpi_madt_oem_check(oem_id, oem_table_id)) {
genapic = apic_probe[i];
printk(KERN_INFO "Setting APIC routing to %s.\n",
genapic->name);
return 1;
}
}
return 0;
}