linux-kernel - Re: [PATCH 2/4] x86/mce/amd: Introduce deferred error interrupt handler

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Message-ID: <20150504184643.GH3829@pd.tnic>
Date:	Mon, 4 May 2015 20:46:43 +0200
From:	Borislav Petkov <bp@...en8.de>
To:	Aravind Gopalakrishnan <aravind.gopalakrishnan@....com>
Cc:	tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
	tony.luck@...el.com, jiang.liu@...ux.intel.com, yinghai@...nel.org,
	x86@...nel.org, dvlasenk@...hat.com, JBeulich@...e.com,
	slaoub@...il.com, luto@...capital.net, dave.hansen@...ux.intel.com,
	oleg@...hat.com, rostedt@...dmis.org, rusty@...tcorp.com.au,
	prarit@...hat.com, linux@...musvillemoes.dk, jroedel@...e.de,
	andriy.shevchenko@...ux.intel.com, macro@...ux-mips.org,
	wangnan0@...wei.com, linux-kernel@...r.kernel.org,
	linux-edac@...r.kernel.org, Robert Richter <rric@...nel.org>
Subject: Re: [PATCH 2/4] x86/mce/amd: Introduce deferred error interrupt
 handler

On Mon, May 04, 2015 at 12:08:16PM -0500, Aravind Gopalakrishnan wrote:
> Not sure if lvt_off_valid() can be reused for deferred error interrupt
> setup. It expects some some of info to be in struct threshold_block
> which is fine for threshold errors and the shifts for offset are
> different too.

I meant that thresholding and IBS is being taken care of by that
function.

> For deferred errors, the workaround is a little different as it
> applies to only the given family/model right now. If the workaround
> needs to be applied for future processors, we can extend the family
> check for those right?

Or, you can do the check for all families as we're behind a CPUID bit
anyway. This is why CPUID bits are a good thing :-)

> If we setup 'm.addr' in amd_threshold_interrupt() and
> amd_deferred_error_interrupt() properly, then amd_decode_mce() would
> actually have some value in m->addr to report.
>
> I didn't mean to say HW doesn't provide us the information in the addr
> and/or the misc registers.

So you can use mce_read_aux(), yeah, you can move it to mce-internal.h

> The addr, misc registers are still valid for threshold, deferred errors.
> (Of course, misc is valid only if m->status & MCI_STATUS_MISCV)
> 
> My point was, in __log_error(), we can read relevant status and addr MSRs to
> be passed to mce_log() as those are the only pieces of information we use in
> the decoding chain; and discard the m.misc assignment we do for threshold
> errors.

But MCx_MISC is important for thresholding errors, it carries the ErrCnt
and stuff.

So you can pass a parameter to __log_error(..., threshold=true, misc)
and do

	if (threshold)
		m.misc = misc;

Right?

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
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