linux-kernel - Re: [PATCH] x86: use hard_smp_processor_id to get apic id in identify

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Message-ID: <4A9587FE.20503@kernel.org>
Date:	Wed, 26 Aug 2009 12:07:42 -0700
From:	Yinghai Lu <yinghai@...nel.org>
To:	Suresh Siddha <suresh.b.siddha@...el.com>
CC:	Ingo Molnar <mingo@...e.hu>, Thomas Gleixner <tglx@...utronix.de>,
	"H. Peter Anvin" <hpa@...or.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Cyrill Gorcunov <gorcunov@...nvz.org>
Subject: Re: [PATCH] x86: use hard_smp_processor_id to get apic id in identify_cpu
 -v2

Suresh Siddha wrote:
> 
> In short, on all the platforms we want to use initial apic id for apicid
> and phys_proc_id. And only on the required platforms like x445, vsmp,
> some AMD platforms, we can have their own mechanisms.
> 
>> 3. for vsmp, and x445, do you want to have c->apicid to have real apic id or the same as initial apic_id?
> 
> On these platforms, c->apicid should be based on their real apic id.
> 
>> this patch is trying to make c->apicid to have real apic_id.
> 
> Can you please modify the patch so that we can have exceptions for
> needed platforms only?
> 

please check this one

[PATCH] x86: use hard_smp_processor_id to get apic id for amd k8 cpus

otherwise, system with apci id lifting will have wrong apicid in
/proc/cpuinfo

and use that in srat_detect_node

Signed-off-by: Yinghai Lu <yinghai@...nel.org>

---
 arch/x86/kernel/cpu/amd.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

Index: linux-2.6/arch/x86/kernel/cpu/amd.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/cpu/amd.c
+++ linux-2.6/arch/x86/kernel/cpu/amd.c
@@ -277,7 +277,7 @@ static void __cpuinit srat_detect_node(s
 #if defined(CONFIG_NUMA) && defined(CONFIG_X86_64)
 	int cpu = smp_processor_id();
 	int node;
-	unsigned apicid = cpu_has_apic ? hard_smp_processor_id() : c->apicid;
+	unsigned apicid = c->apicid;
 
 	node = c->phys_proc_id;
 	if (apicid_to_node[apicid] != NUMA_NO_NODE)
@@ -437,6 +437,9 @@ static void __cpuinit init_amd(struct cp
 	}
 	if (c->x86 == 0x10 || c->x86 == 0x11)
 		set_cpu_cap(c, X86_FEATURE_REP_GOOD);
+
+	/* get apicid instead of initial apic id from cpuid */
+	c->apicid = hard_smp_processor_id();
 #else
 
 	/*
--
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