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>
#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);
[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 17:27:04 +00:00
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)
{
[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 17:27:04 +00:00
#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;
[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 17:27:04 +00:00
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);
}