linux-kernel - Re: [PATCH v2 3/7] ACPI / APEI: add OSC APEI bit check for ghes

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Date:   Fri, 4 Aug 2017 20:49:51 +0000
From:   "Kani, Toshimitsu" <toshi.kani@....com>
To:     "bp@...en8.de" <bp@...en8.de>
CC:     "linux-edac@...r.kernel.org" <linux-edac@...r.kernel.org>,
        "lenb@...nel.org" <lenb@...nel.org>,
        "mchehab@...nel.org" <mchehab@...nel.org>,
        "tony.luck@...el.com" <tony.luck@...el.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "rjw@...ysocki.net" <rjw@...ysocki.net>,
        "linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>
Subject: Re: [PATCH v2 3/7] ACPI / APEI: add OSC APEI bit check for ghes_edac

On Fri, 2017-08-04 at 05:44 +0200, Borislav Petkov wrote:
> On Thu, Aug 03, 2017 at 03:57:49PM -0600, Toshi Kani wrote:
> > When 'osc_sb_apei_support_acked' is set, it indicates that
> > the platform supports APEI, firmware-first mode, as ACPI _OSC
> > capability bit 4, APEI Support, was set in query.  While _OSC
> > is an optional method, platforms with APEI support should
> > implement it to inform its capability to the OS properly.
> > 
> > Add check to 'osc_sb_apei_support_acked' before calling
> > ghes_edac_register() to restrict that ghes_edac is enabled
> > on platforms with APEI support capability set in _OSC.
> > 
> > Signed-off-by: Toshi Kani <toshi.kani@....com>
> > Cc: "Rafael J. Wysocki" <rjw@...ysocki.net>
> > Cc: Borislav Petkov <bp@...en8.de>
> > Cc: Mauro Carvalho Chehab <mchehab@...nel.org>
> > Cc: Tony Luck <tony.luck@...el.com>
> > ---
> >  drivers/acpi/apei/ghes.c |    8 +++++---
> >  1 file changed, 5 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
> > index d661d45..49d75eb 100644
> > --- a/drivers/acpi/apei/ghes.c
> > +++ b/drivers/acpi/apei/ghes.c
> > @@ -1139,9 +1139,11 @@ static int ghes_probe(struct platform_device
> > *ghes_dev)
> >  		goto err;
> >  	}
> >  
> > -	rc = ghes_edac_register(ghes, &ghes_dev->dev);
> > -	if (rc < 0)
> > -		goto err;
> > +	if (osc_sb_apei_support_acked) {
> 
> What for when we have the whitelist?

Some firmware features can be enabled / disabled in BIOS.  While HPE
firmware does not allow to disable FF, it's possible that other vendors
might allow such and still have the same OEM ID info.  So, this check
makes sure that FF is in fact enabled in firmware.

Thanks,
-Toshi