linux-kernel - Re: [PATCH 1/5] x86/ras: Merge Intel and AMD ppin

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Message-ID: <Yect7WSUSmj54yBG@zn.tnic>
Date:   Tue, 18 Jan 2022 22:15:25 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     "Luck, Tony" <tony.luck@...el.com>
Cc:     x86@...nel.org, linux-kernel@...r.kernel.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Smita Koralahalli Channabasappa 
        <smita.koralahallichannabasappa@....com>,
        Wei Huang <wei.huang2@....com>,
        Tom Lendacky <thomas.lendacky@....com>, patches@...ts.linux.dev
Subject: Re: [PATCH 1/5] x86/ras: Merge Intel and AMD ppin_init() functions

On Tue, Jan 18, 2022 at 01:03:19PM -0800, Luck, Tony wrote:
> You are much braver than I :-)  How confident are you
> that nobody implicitly depends on those?

So I'm willing to do it just to piss off all those who do, frankly.
Because that's a kernel-internal define and *nothing* should use it...

But looking at print_cpu_modalias(), that thing issues uevents and am
I willing to guarantee that nothing in luserspace uses those naked
numbers?

Probably not. ;-\

That's how it looks like here and there's ven0002.

/sys/devices/system/cpu/cpu11/uevent:MODALIAS=cpu:type:x86,ven0002fam0017mod0008:feature:,0000,0001,0002,0003,0004,0005,0006,
0007,0008,0009,000B,000C,000D,000E,000F,0010,0011,0013,0017,0018,0019,001A,001C,0020,0021,0022,0023,0024,0025,0026,0027,0028,
0029,002B,002C,002D,002E,002F,0030,0031,0034,0036,0037,0038,0039,003A,003B,003D,0064,0068,006E,0070,0072,0074,0075,0078,0079,
007A,007C,007D,0080,0081,0083,0089,008C,008D,0093,0094,0096,0097,0099,009A,009B,009C,009D,009E,00C0,00C1,00C2,00C3,00C4,00C5,
00C6,00C7,00C8,00C9,00CC,00CD,00D1,00D6,00D7,00D8,00DA,00DC,00DD,00E2,00E8,00EC,00ED,00F1,00F3,00F5,00F8,00FA,00FC,010F,0120,
0123,0125,0127,0128,0132,0133,0134,0137,013D,0140,0141,0142,0143,0165,01A0,01A1,01A2,01AC,01C2,01E0,01E1,01E2,01E3,01E4,01E5,
01E6,01E7,01EA,01EB,01EC,01ED,01EF,01F0,0220,0221,0223,0224,0260,0261,0262,0263

> Is it worth the risk/churn just to save 12 bytes in the ppin_info[]
> array?

It doesn't look like it.

> I'll fix up all the other stuff you found and post a V2 soon. Thanks
> for the review.

Please hold off until I've looked at the rest.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette