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Commit f8d31193 authored by Andi Kleen's avatar Andi Kleen Committed by Linus Torvalds
Browse files

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



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: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 37a47e65

arch/x86_64/kernel/genapic.c

+24 −9
Original line number Diff line number Diff line
@@ -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)

		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;

arch/x86_64/kernel/genapic_flat.c

+61 −1
Original line number Diff line number Diff line
@@ -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,

};