linux-kernel - Re: [PATCH 2/7] EDAC/mce_amd: Remove SMCA Extended Error code descriptions

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Date:   Thu, 20 Jul 2023 20:55:01 +0530
From:   "M K, Muralidhara" <muralimk@....com>
To:     Borislav Petkov <bp@...en8.de>
Cc:     linux-edac@...r.kernel.org, x86@...nel.org,
        linux-kernel@...r.kernel.org, mingo@...hat.com, mchehab@...nel.org,
        nchatrad@....com, yazen.ghannam@....com,
        Muralidhara M K <muralidhara.mk@....com>
Subject: Re: [PATCH 2/7] EDAC/mce_amd: Remove SMCA Extended Error code
 descriptions

Hi Boris,

On 7/20/2023 7:29 PM, Borislav Petkov wrote:
> Caution: This message originated from an External Source. Use proper caution when opening attachments, clicking links, or responding.
> 
> 
> On Thu, Jul 20, 2023 at 12:54:20PM +0000, Muralidhara M K wrote:
>> From: Muralidhara M K <muralidhara.mk@....com>
>>
>> On AMD systems with Scalable MCA, each machine check error of a SMCA bank
>> type has an associated bit position in the bank's control (CTL) register.
>>
>> An error's bit position in the CTL register is used during error decoding
>> for offsetting into the corresponding bank's error description structure.
>> As new errors are being added in newer AMD systems for existing SMCA bank
>> types, the underlying SMCA architecture guarantees that the bit positions
>> of existing errors are not altered.
>>
>> However, on some AMD systems some of the existing bit definitions in the
>> CTL register of SMCA bank type are reassigned without defining new HWID
>> and McaType. Consequently, the errors whose bit definitions have been
>> reassigned in the CTL register are being erroneously decoded.
>>
>> Remove SMCA Extended Error Code descriptions. This avoids decoding issues
>> for incorrectly reassigned bits, and avoids the related maintenance burden
>> in the kernel. This decoding can be done in external tools or by referring
>> to AMD documentation. The bank type and Extended Error Code value for an
>> error will continue to be printed as a convenience.
>>
>> Signed-off-by: Muralidhara M K <muralidhara.mk@....com>
>> Reviewed-by: Yazen Ghannam <yazen.ghannam@....com>
>> ---
>>   drivers/edac/mce_amd.c | 480 -----------------------------------------
>>   1 file changed, 480 deletions(-)
> 
> This needs to stay until rasdaemon has support for decoding errors - and
> I've told you already.
> 
> Lemme tell you again, maybe it'll stick this time.
> 
> In any case, NAK.
> 

Pull request created in rasdaemon for the same.
https://github.com/mchehab/rasdaemon/pull/106/commits/09026653864305b7a91dcb3604b91a9c0c0d74f3

> --
> Regards/Gruss,
>      Boris.
> 
> https://people.kernel.org/tglx/notes-about-netiquette
>