linux-kernel - Re: [RFC PATCH] x86/cpu/hygon: Fix phys_proc_id calculation logic for multi-die processor

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Message-ID: <a31e6d79-bc60-b339-185b-58649516aae5@hygon.cn>
Date:   Sat, 23 Mar 2019 11:00:08 +0800
From:   Pu Wen <puwen@...on.cn>
To:     Peter Zijlstra <peterz@...radead.org>,
        Borislav Petkov <bp@...en8.de>
CC:     "tglx@...utronix.de" <tglx@...utronix.de>,
        "mingo@...hat.com" <mingo@...hat.com>,
        "hpa@...or.com" <hpa@...or.com>, "x86@...nel.org" <x86@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [RFC PATCH] x86/cpu/hygon: Fix phys_proc_id calculation logic for
 multi-die processor

On 2019/3/23 0:52, Peter Zijlstra wrote:
> On Fri, Mar 22, 2019 at 05:44:45PM +0100, Borislav Petkov wrote:
>> On Sat, Mar 23, 2019 at 12:19:01AM +0800, Pu Wen wrote:
>>> That 6 is not a magic number.
>>
>> Well, if I see a naked 6, then it is only magic to me. Now if it were a
>> proper define with a descriptive name...
> 
> Does AMD/Hygon not have a CPUID leaf to read useful things like this
> from?

ApicId[6] is read from CPUID_Fn00000001_EBX[30].
Please see section 2.1.11.1 and 2.1.10.2.1.3 of referrence [1].

Reference:
[1] https://www.amd.com/system/files/TechDocs/54945_PPR_Family_17h_Models_00h-0Fh.pdf

-- 
Regards,
Pu Wen