Re: [PATCH 1/3] x86/MCE, EDAC/mce_amd: Add support for new MCA_SYND{1,2} registers

From: Borislav Petkov <bp@alien8.de>
To: Yazen Ghannam <yazen.ghannam@amd.com>
Cc: linux-edac@vger.kernel.org, linux-kernel@vger.kernel.org,
	tony.luck@intel.com, x86@kernel.org,
	Smita.KoralahalliChannabasappa@amd.com
Subject: Re: [PATCH 1/3] x86/MCE, EDAC/mce_amd: Add support for new MCA_SYND{1,2} registers
Date: Mon, 18 Jul 2022 10:57:19 +0200	[thread overview]
Message-ID: <YtUgb2Y/H/Wq9yIn@zn.tnic> (raw)
In-Reply-To: <YsxefXQDCiJ1zxLG@yaz-fattaah>

On Mon, Jul 11, 2022 at 05:31:41PM +0000, Yazen Ghannam wrote:
> Is your concern specifically on growing/changing struct mce, or is it more
> about limiting info sent to userspace?

Well, both, kinda.

> If it's the former, then I've been thinking it would be good to introduce a
> new internal "struct mce_ext" that includes struct mce plus other things. This
> way struct mce can still be uapi, and things like mcelog can use it. And at
> the same time we can new data used in the kernel or shared through
> tracepoints.
> 
> /* Extended MCE structure */
> struct mce_ext {
> 	struct mce *m;
> 	/* new stuff here */
> };
> 
> What do you think?

The moment you make it part of a trace record, it practically becomes
ABI.

So we could have some opaque blob which is called vendor-specific data
and which is dumped raw to userspace, without any specification to its
format so that luserspace doesn't get any ideas...

Lemme talk to rostedt.

-- 
Regards/Gruss,
    Boris.

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