linux-kernel - Re: [PATCH] acpi: apei: call into AER handling regardless of severity

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Message-ID: <9abb2e99-44be-3315-47d9-2689b6c76d79@codeaurora.org>
Date:   Tue, 29 Aug 2017 15:27:42 -0600
From:   "Baicar, Tyler" <tbaicar@...eaurora.org>
To:     Borislav Petkov <bp@...e.de>
Cc:     rjw@...ysocki.net, lenb@...nel.org, will.deacon@....com,
        james.morse@....com, prarit@...hat.com, punit.agrawal@....com,
        shiju.jose@...wei.com, andriy.shevchenko@...ux.intel.com,
        linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] acpi: apei: call into AER handling regardless of severity

On 8/29/2017 2:20 AM, Borislav Petkov wrote:
> On Mon, Aug 28, 2017 at 11:11:54AM -0600, Tyler Baicar wrote:
>> Currently the GHES code only calls into the AER driver for
>> recoverable type errors. This is incorrect because errors of
>> other severities do not get logged by the AER driver and do not
>> get exposed to user space via the AER trace event. So, call
>> into the AER driver for PCIe errors regardless of the severity.
>>
>> Signed-off-by: Tyler Baicar <tbaicar@...eaurora.org>
>> ---
>>   drivers/acpi/apei/ghes.c | 4 +---
>>   1 file changed, 1 insertion(+), 3 deletions(-)
>>
>> diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
>> index d661d45..5cab238 100644
>> --- a/drivers/acpi/apei/ghes.c
>> +++ b/drivers/acpi/apei/ghes.c
>> @@ -489,9 +489,7 @@ static void ghes_do_proc(struct ghes *ghes,
>>   		else if (guid_equal(sec_type, &CPER_SEC_PCIE)) {
>>   			struct cper_sec_pcie *pcie_err = acpi_hest_get_payload(gdata);
>>   
>> -			if (sev == GHES_SEV_RECOVERABLE &&
>> -			    sec_sev == GHES_SEV_RECOVERABLE &&
> Did you make the effort to see which commit added those lines and read
> its commit message?
>
> Doesn't look like it...
Hello Boris,

Here is that commit text:

"ACPI, APEI, GHES: Add PCIe AER recovery support

     aer_recover_queue() is called when recoverable PCIe AER errors are
     notified by firmware to do the recovery work."

The function with the real bulk of the code we need here is 
aer_recover_work_func() which calls into cper_print_aer() and 
do_recovery(). The do_recovery() function is the only function that 
should be specific to recoverable errors. We need cper_print_aer() to 
handle printing of AER specific information and to trigger the aer_event 
to notify user space. Otherwise tools such as RAS Daemon will not be 
notified of correctable type PCIe errors. You can clearly see by looking 
at cper_print_aer() that it expects to be called with correctable errors 
as well. To avoid calling the do_recovery() function for correctable 
errors I created https://patchwork.kernel.org/patch/9925877/

The AER core framework for non-FF systems prints all the AER error 
information for all errors and then only calls do_recovery() for 
non-correctable errors. See aer_process_err_devices() and 
handle_error_source().

Thanks,
Tyler

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