linux-kernel - [PATCH] x86, amd: Probe CPUs by APICID instead of initial APICID

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Date:	Tue, 17 Apr 2012 13:06:36 +0300
From:	Vlad Zolotarov <vlad@...lemp.com>
To:	linux-kernel@...r.kernel.org, tglx@...utronix.de, mingo@...hat.com,
	hpa@...or.com
Cc:	andreas.herrmann3@....com, borislav.petkov@....com,
	Ravikiran.Thirumalai@....com,
	"Shai Fultheim (Shai@...leMP.com)" <Shai@...lemp.com>
Subject: [PATCH] x86, amd: Probe CPUs by APICID instead of initial APICID

From: Shai Fultheim <shai@...lemp.com>

Make AMD identify processors using APICID (32 bit) rather than the initial 
APICID (8 bit).  This is critical to make sure the last level cache (llc), 
which is used for sibling detection, will be different between boards - on 
aggregated systems with more than 8 processors.


Signed-off-by: Shai Fultheim <shai@...lemp.com>
Signed-off-by: Vlad Zolotarov <vlad@...lemp.com>
---
 arch/x86/kernel/cpu/amd.c |   10 +++++-----
 1 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 0bab2b1..33d9502 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -277,7 +277,7 @@ static void __cpuinit amd_get_topology(struct cpuinfo_x86 *c)
 
 		cpuid(0x8000001e, &eax, &ebx, &ecx, &edx);
 		nodes = ((ecx >> 8) & 7) + 1;
-		node_id = ecx & 7;
+		node_id = (ecx & 7) + (c->phys_proc_id << 3);
 
 		/* get compute unit information */
 		smp_num_siblings = ((ebx >> 8) & 3) + 1;
@@ -288,7 +288,7 @@ static void __cpuinit amd_get_topology(struct cpuinfo_x86 *c)
 
 		rdmsrl(MSR_FAM10H_NODE_ID, value);
 		nodes = ((value >> 3) & 7) + 1;
-		node_id = value & 7;
+		node_id = (value & 7) + (c->phys_proc_id << 3);
 	} else
 		return;
 
@@ -323,9 +323,9 @@ static void __cpuinit amd_detect_cmp(struct cpuinfo_x86 *c)
 
 	bits = c->x86_coreid_bits;
 	/* Low order bits define the core id (index of core in socket) */
-	c->cpu_core_id = c->initial_apicid & ((1 << bits)-1);
-	/* Convert the initial APIC ID into the socket ID */
-	c->phys_proc_id = c->initial_apicid >> bits;
+	c->cpu_core_id = c->apicid & ((1 << bits)-1);
+	/* Convert the APIC ID into the socket ID */
+	c->phys_proc_id = c->apicid >> bits;
 	/* use socket ID also for last level cache */
 	per_cpu(cpu_llc_id, cpu) = c->phys_proc_id;
 	amd_get_topology(c);
-- 
1.7.7.6

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