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

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Date:	Tue, 5 May 2015 13:39:03 -0500
From:	Aravind Gopalakrishnan <aravind.gopalakrishnan@....com>
To:	Borislav Petkov <bp@...en8.de>
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 5/4/2015 1:46 PM, Borislav Petkov wrote:
> So you can use mce_read_aux(), yeah, you can move it to mce-internal.h 

Re-using mce_read_aux() was not as trivial as I initially thought.
The MISC address value we read in amd_threshold_interrupt() could also 
be the value
in MSR0xc0000408 or MSR0xc0000409 (for a bank == 4 case). But in 
mce_read_aux(), we will only
look at MSR_IA32_MCx_MISC(i) (which is 0x413 for bank = 4)

So, instead of mucking around with mce_read_aux(), I am reusing the 
'misc' value from amd_threshold_interrupt()
and just adding rdmsrl(MSR_IA32_MCx_ADDR(bank), m.addr)

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

Here's how I have it currently-
static void __log_error(unsigned int bank, bool is_thr, u64 misc)
{
         struct mce m;

         mce_setup(&m);
         rdmsrl(MSR_IA32_MCx_STATUS(bank), m.status);
         if (!(m.status & MCI_STATUS_VAL))
                 return;

         if (is_thr)
                 m.misc = misc;

         m.bank = bank;
         rdmsrl(MSR_IA32_MCx_ADDR(bank), m.addr);
         mce_log(&m);

         wrmsrl(MSR_IA32_MCx_STATUS(bank), 0);
}

and works fine..

Before patch:

     [76916.275587] [Hardware Error]: Corrected error, no action required.
     [76916.279576] [Hardware Error]: CPU:0 (15:60:0) 
MC0_STATUS[-|CE|-|-|AddrV|-|-|CECC]: 0x840041000028017b
     [76916.279576] [Hardware Error]: MC0 Error Address: 0x0000000000000000

Corrected error output:
     [  102.623490] [Hardware Error]: Corrected error, no action required.
     [  102.623668] [Hardware Error]: CPU:0 (15:60:0) 
MC0_STATUS[-|CE|-|-|AddrV|-|-|CECC]: 0x840041000028017b
     [  102.623930] [Hardware Error]: MC0 Error Address: 0x00001f808f0ff040

Thanks,
-Aravind.
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