linux-kernel - RE: [PATCH 2/3] x86/MCE/AMD, EDAC/mce_amd: Enumerate Reserved SMCA bank type

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Date:   Wed, 14 Feb 2018 16:28:28 +0000
From:   "Ghannam, Yazen" <Yazen.Ghannam@....com>
To:     Borislav Petkov <bp@...en8.de>
CC:     "linux-edac@...r.kernel.org" <linux-edac@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "bp@...e.de" <bp@...e.de>,
        "tony.luck@...el.com" <tony.luck@...el.com>,
        "x86@...nel.org" <x86@...nel.org>
Subject: RE: [PATCH 2/3] x86/MCE/AMD, EDAC/mce_amd: Enumerate Reserved SMCA
 bank type

> -----Original Message-----
> From: linux-edac-owner@...r.kernel.org [mailto:linux-edac-
> owner@...r.kernel.org] On Behalf Of Borislav Petkov
> Sent: Thursday, February 8, 2018 10:15 AM
> To: Ghannam, Yazen <Yazen.Ghannam@....com>
> Cc: linux-edac@...r.kernel.org; linux-kernel@...r.kernel.org; bp@...e.de;
> tony.luck@...el.com; x86@...nel.org
> Subject: Re: [PATCH 2/3] x86/MCE/AMD, EDAC/mce_amd: Enumerate Reserved
> SMCA bank type
> 
> On Thu, Feb 01, 2018 at 12:48:12PM -0600, Yazen Ghannam wrote:
> > From: Yazen Ghannam <yazen.ghannam@....com>
> >
> > Currently, bank 4 is reserved on Fam17h, so we chose not to initialize
> > bank 4 in the smca_banks array. This means that when we check if a bank
> > is initialized, like during boot or resume, we will see that bank 4 is
> > not initialized and try to initialize it. This may cause a call trace,
> > when resuming from suspend, due to *on_cpu() calls in the init path.
> 
> Please be more specific: the rdmsr_*_on_cpu() calls issue an IPI but we're
> running with interrupts disabled, which triggers:
> 
>  WARNING: CPU: 0 PID: 11523 at kernel/smp.c:291
> smp_call_function_single+0xdc/0xe0
> 

Okay.

...
> > @@ -433,6 +437,9 @@ static u32 get_block_address(unsigned int cpu, u32
> current_addr, u32 low, u32 hi
> >  	u32 addr = 0, offset = 0;
> >
> >  	if (mce_flags.smca) {
> 
> As a last patch in the series: please carve the code in this
> if-statement into a smca_get_block_address() helper. And it doesn't need
> the stable tag as it is only a cleanup.
> 

Will do.

Thanks,
Yazen