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git.proxmox.com Git - mirror_ubuntu-jammy-kernel.git/blob - arch/x86_64/kernel/genapic.c
2 * Copyright 2004 James Cleverdon, IBM.
3 * Subject to the GNU Public License, v.2
5 * Generic APIC sub-arch probe layer.
7 * Hacked for x86-64 by James Cleverdon from i386 architecture code by
8 * Martin Bligh, Andi Kleen, James Bottomley, John Stultz, and
11 #include <linux/config.h>
12 #include <linux/threads.h>
13 #include <linux/cpumask.h>
14 #include <linux/string.h>
15 #include <linux/kernel.h>
16 #include <linux/ctype.h>
17 #include <linux/init.h>
18 #include <linux/module.h>
23 /* which logical CPU number maps to which CPU (physical APIC ID) */
24 u8 x86_cpu_to_apicid
[NR_CPUS
] = { [0 ... NR_CPUS
-1] = BAD_APICID
};
25 EXPORT_SYMBOL(x86_cpu_to_apicid
);
26 u8 x86_cpu_to_log_apicid
[NR_CPUS
] = { [0 ... NR_CPUS
-1] = BAD_APICID
};
28 extern struct genapic apic_cluster
;
29 extern struct genapic apic_flat
;
31 struct genapic
*genapic
= &apic_flat
;
35 * Check the APIC IDs in bios_cpu_apicid and choose the APIC mode.
37 void __init
clustered_apic_check(void)
40 u8 clusters
, max_cluster
;
42 u8 cluster_cnt
[NUM_APIC_CLUSTERS
];
44 if (boot_cpu_data
.x86_vendor
== X86_VENDOR_AMD
) {
45 /* AMD always uses flat mode right now */
50 memset(cluster_cnt
, 0, sizeof(cluster_cnt
));
52 for (i
= 0; i
< NR_CPUS
; i
++) {
53 id
= bios_cpu_apicid
[i
];
55 cluster_cnt
[APIC_CLUSTERID(id
)]++;
60 for (i
= 0; i
< NUM_APIC_CLUSTERS
; i
++) {
61 if (cluster_cnt
[i
] > 0) {
63 if (cluster_cnt
[i
] > max_cluster
)
64 max_cluster
= cluster_cnt
[i
];
69 * If we have clusters <= 1 and CPUs <= 8 in cluster 0, then flat mode,
70 * else if max_cluster <= 4 and cluster_cnt[15] == 0, clustered logical
72 * (We don't use lowest priority delivery + HW APIC IRQ steering, so
73 * can ignore the clustered logical case and go straight to physical.)
75 if (clusters
<= 1 && max_cluster
<= 8 && cluster_cnt
[0] == max_cluster
)
78 genapic
= &apic_cluster
;
81 printk(KERN_INFO
"Setting APIC routing to %s\n", genapic
->name
);
84 /* Same for both flat and clustered. */
86 void send_IPI_self(int vector
)
88 __send_IPI_shortcut(APIC_DEST_SELF
, vector
, APIC_DEST_PHYSICAL
);