linux-kernel - Re: [RFC PATCH v3 2/3] acpi: apei: Do not panic() on PCIe errors reported through GHES

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Date:   Thu, 26 Apr 2018 12:44:57 -0500
From:   "Alex G." <mr.nuke.me@...il.com>
To:     Borislav Petkov <bp@...en8.de>
Cc:     linux-acpi@...r.kernel.org, linux-edac@...r.kernel.org,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Len Brown <lenb@...nel.org>, Tony Luck <tony.luck@...el.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Robert Moore <robert.moore@...el.com>,
        Erik Schmauss <erik.schmauss@...el.com>,
        Tyler Baicar <tbaicar@...eaurora.org>,
        Will Deacon <will.deacon@....com>,
        James Morse <james.morse@....com>,
        Shiju Jose <shiju.jose@...wei.com>,
        "Jonathan (Zhixiong) Zhang" <zjzhang@...eaurora.org>,
        Dongjiu Geng <gengdongjiu@...wei.com>,
        linux-kernel@...r.kernel.org, devel@...ica.org,
        austin_bolen@...l.com, alex_gagniuc@...lteam.com,
        shyam_iyer@...l.com
Subject: Re: [RFC PATCH v3 2/3] acpi: apei: Do not panic() on PCIe errors
 reported through GHES

Hi Borislav,

On 04/26/2018 06:19 AM, Borislav Petkov wrote:
> On Wed, Apr 25, 2018 at 03:39:50PM -0500, Alexandru Gagniuc wrote:
>> @@ -932,7 +971,7 @@ static void __process_error(struct ghes *ghes)
>>   static int ghes_notify_nmi(unsigned int cmd, struct pt_regs *regs)
>>   {
>>   	struct ghes *ghes;
>> -	int sev, ret = NMI_DONE;
>> +	int sev, asev, ret = NMI_DONE;
>>   
>>   	if (!atomic_add_unless(&ghes_in_nmi, 1, 1))
>>   		return ret;
>> @@ -945,8 +984,9 @@ static int ghes_notify_nmi(unsigned int cmd, struct pt_regs *regs)
>>   			ret = NMI_HANDLED;
>>   		}
>>   
>> +		asev = ghes_actual_severity(ghes);
>>   		sev = ghes_severity(ghes->estatus->error_severity);
> 
> So renaming ghes_deferrable_severity() to ghes_actual_severity() is not
> a big change. And that's not what I meant.

I'm sorry I misunderstood you.

> I'd like to see here:
> 
> 		 sev = ghes_severity(ghes);

		 sev = ghes_severity(ghes);


> and inside you do all the required mapping/severity processing/etc. And
> you can rename the current ghes_severity() to ghes_map_cper_severity()
> or whatever...

I agree that the current ghes_severity() name is vague. I'll get it done 
properly in v4 (next week).

>> -		if (sev >= GHES_SEV_PANIC) {
>> +		if ((sev >= GHES_SEV_PANIC) && (asev >= GHES_SEV_PANIC)) {
> 
> ... so that this change doesn't happen and there are not two severities
> queried but a single one.

Two severities is a result of the wanky GHES data structure. Nothing 
says we have to use the severity field in the header... if you're okay 
with just ignoring it.

Alex