forked from Minki/linux
6c231b7bab
Mark variables which are usually accessed for reads with __readmostly. Signed-off-by: Alok N Kataria <alokk@calsoftinc.com> Signed-off-by: Shai Fultheim <shai@scalex86.org> Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
121 lines
3.1 KiB
C
121 lines
3.1 KiB
C
/*
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* Copyright 2004 James Cleverdon, IBM.
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* Subject to the GNU Public License, v.2
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*
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* Generic APIC sub-arch probe layer.
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*
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* Hacked for x86-64 by James Cleverdon from i386 architecture code by
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* Martin Bligh, Andi Kleen, James Bottomley, John Stultz, and
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* James Cleverdon.
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*/
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#include <linux/config.h>
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#include <linux/threads.h>
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#include <linux/cpumask.h>
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#include <linux/string.h>
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#include <linux/kernel.h>
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#include <linux/ctype.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <asm/smp.h>
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#include <asm/ipi.h>
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#if defined(CONFIG_ACPI_BUS)
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#include <acpi/acpi_bus.h>
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#endif
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/* which logical CPU number maps to which CPU (physical APIC ID) */
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u8 x86_cpu_to_apicid[NR_CPUS] __read_mostly = { [0 ... NR_CPUS-1] = BAD_APICID };
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EXPORT_SYMBOL(x86_cpu_to_apicid);
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u8 x86_cpu_to_log_apicid[NR_CPUS] = { [0 ... NR_CPUS-1] = BAD_APICID };
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extern struct genapic apic_cluster;
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extern struct genapic apic_flat;
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extern struct genapic apic_physflat;
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struct genapic *genapic = &apic_flat;
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/*
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* Check the APIC IDs in bios_cpu_apicid and choose the APIC mode.
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*/
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void __init clustered_apic_check(void)
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{
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long i;
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u8 clusters, max_cluster;
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u8 id;
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u8 cluster_cnt[NUM_APIC_CLUSTERS];
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int num_cpus = 0;
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#if defined(CONFIG_ACPI_BUS)
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/*
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* Some x86_64 machines use physical APIC mode regardless of how many
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* procs/clusters are present (x86_64 ES7000 is an example).
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*/
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if (acpi_fadt.revision > FADT2_REVISION_ID)
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if (acpi_fadt.force_apic_physical_destination_mode) {
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genapic = &apic_cluster;
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goto print;
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}
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#endif
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memset(cluster_cnt, 0, sizeof(cluster_cnt));
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for (i = 0; i < NR_CPUS; i++) {
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id = bios_cpu_apicid[i];
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if (id == BAD_APICID)
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continue;
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num_cpus++;
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cluster_cnt[APIC_CLUSTERID(id)]++;
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}
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/* Don't use clustered mode on AMD platforms. */
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if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) {
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genapic = &apic_physflat;
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#ifndef CONFIG_CPU_HOTPLUG
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/* In the CPU hotplug case we cannot use broadcast mode
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because that opens a race when a CPU is removed.
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Stay at physflat mode in this case.
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It is bad to do this unconditionally though. Once
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we have ACPI platform support for CPU hotplug
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we should detect hotplug capablity from ACPI tables and
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only do this when really needed. -AK */
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if (num_cpus <= 8)
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genapic = &apic_flat;
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#endif
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goto print;
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}
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clusters = 0;
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max_cluster = 0;
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for (i = 0; i < NUM_APIC_CLUSTERS; i++) {
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if (cluster_cnt[i] > 0) {
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++clusters;
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if (cluster_cnt[i] > max_cluster)
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max_cluster = cluster_cnt[i];
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}
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}
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/*
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* If we have clusters <= 1 and CPUs <= 8 in cluster 0, then flat mode,
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* else if max_cluster <= 4 and cluster_cnt[15] == 0, clustered logical
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* else physical mode.
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* (We don't use lowest priority delivery + HW APIC IRQ steering, so
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* can ignore the clustered logical case and go straight to physical.)
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*/
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if (clusters <= 1 && max_cluster <= 8 && cluster_cnt[0] == max_cluster)
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genapic = &apic_flat;
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else
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genapic = &apic_cluster;
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print:
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printk(KERN_INFO "Setting APIC routing to %s\n", genapic->name);
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}
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/* Same for both flat and clustered. */
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void send_IPI_self(int vector)
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{
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__send_IPI_shortcut(APIC_DEST_SELF, vector, APIC_DEST_PHYSICAL);
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}
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