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[PATCH] x86_64: Support more than 8 cores on AMD systems

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Use physical mode instead of logical mode to address more CPUs.  This is also
used in the CPU hotplug case to avoid a race.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Andi Kleen 2005-07-28 21:15:42 -07:00 committed by Linus Torvalds
parent 37a47e65fa
commit f8d311939f
2 changed files with 85 additions and 10 deletions
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33
arch/x86_64/kernel/genapic.c
View file

@ -31,6 +31,7 @@ u8 x86_cpu_to_log_apicid[NR_CPUS] = { [0 ... NR_CPUS-1] = BAD_APICID };
extern struct genapic apic_cluster;
extern struct genapic apic_flat;
extern struct genapic apic_physflat;
struct genapic *genapic = &apic_flat;
@ -44,12 +45,7 @@ void __init clustered_apic_check(void)
u8 clusters, max_cluster;
u8 id;
u8 cluster_cnt[NUM_APIC_CLUSTERS];
if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) {
/* AMD always uses flat mode right now */
genapic = &apic_flat;
goto print;
}
int num_cpus = 0;
#if defined(CONFIG_ACPI_BUS)
/*
@ -64,15 +60,34 @@ void __init clustered_apic_check(void)
#endif
memset(cluster_cnt, 0, sizeof(cluster_cnt));
for (i = 0; i < NR_CPUS; i++) {
id = bios_cpu_apicid[i];
if (id != BAD_APICID)
cluster_cnt[APIC_CLUSTERID(id)]++;
if (id == BAD_APICID)
continue;
num_cpus++;
cluster_cnt[APIC_CLUSTERID(id)]++;
}
/* Don't use clustered mode on AMD platforms. */
if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) {
genapic = &apic_physflat;
#ifndef CONFIG_CPU_HOTPLUG
/* In the CPU hotplug case we cannot use broadcast mode
because that opens a race when a CPU is removed.
Stay at physflat mode in this case.
It is bad to do this unconditionally though. Once
we have ACPI platform support for CPU hotplug
we should detect hotplug capablity from ACPI tables and
only do this when really needed. -AK */
if (num_cpus <= 8)
genapic = &apic_flat;
#endif
goto print;
}
clusters = 0;
max_cluster = 0;
for (i = 0; i < NUM_APIC_CLUSTERS; i++) {
if (cluster_cnt[i] > 0) {
++clusters;

62
arch/x86_64/kernel/genapic_flat.c
View file

@ -2,7 +2,7 @@
* Copyright 2004 James Cleverdon, IBM.
* Subject to the GNU Public License, v.2
*
* Flat APIC subarch code. Maximum 8 CPUs, logical delivery.
* Flat APIC subarch code.
*
* Hacked for x86-64 by James Cleverdon from i386 architecture code by
* Martin Bligh, Andi Kleen, James Bottomley, John Stultz, and
@ -119,3 +119,63 @@ struct genapic apic_flat = {
.cpu_mask_to_apicid = flat_cpu_mask_to_apicid,
.phys_pkg_id = phys_pkg_id,
};
/*
* Physflat mode is used when there are more than 8 CPUs on a AMD system.
* We cannot use logical delivery in this case because the mask
* overflows, so use physical mode.
*/
static cpumask_t physflat_target_cpus(void)
{
return cpumask_of_cpu(0);
}
static void physflat_send_IPI_mask(cpumask_t cpumask, int vector)
{
send_IPI_mask_sequence(cpumask, vector);
}
static void physflat_send_IPI_allbutself(int vector)
{
cpumask_t allbutme = cpu_online_map;
int me = get_cpu();
cpu_clear(me, allbutme);
physflat_send_IPI_mask(allbutme, vector);
put_cpu();
}
static void physflat_send_IPI_all(int vector)
{
physflat_send_IPI_mask(cpu_online_map, vector);
}
static unsigned int physflat_cpu_mask_to_apicid(cpumask_t cpumask)
{
int cpu;
/*
* We're using fixed IRQ delivery, can only return one phys APIC ID.
* May as well be the first.
*/
cpu = first_cpu(cpumask);
if ((unsigned)cpu < NR_CPUS)
return x86_cpu_to_apicid[cpu];
else
return BAD_APICID;
}
struct genapic apic_physflat = {
.name = "physical flat",
.int_delivery_mode = dest_LowestPrio,
.int_dest_mode = (APIC_DEST_PHYSICAL != 0),
.int_delivery_dest = APIC_DEST_PHYSICAL | APIC_DM_LOWEST,
.target_cpus = physflat_target_cpus,
.apic_id_registered = flat_apic_id_registered,
.init_apic_ldr = flat_init_apic_ldr,/*not needed, but shouldn't hurt*/
.send_IPI_all = physflat_send_IPI_all,
.send_IPI_allbutself = physflat_send_IPI_allbutself,
.send_IPI_mask = physflat_send_IPI_mask,
.cpu_mask_to_apicid = physflat_cpu_mask_to_apicid,
.phys_pkg_id = phys_pkg_id,
};