linux-kernel - Re: [PATCH V10 07/10] efi: print unrecognized CPER section

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Message-ID: <58AC9093.5020303@arm.com>
Date:   Tue, 21 Feb 2017 19:10:11 +0000
From:   James Morse <james.morse@....com>
To:     Tyler Baicar <tbaicar@...eaurora.org>
CC:     christoffer.dall@...aro.org, marc.zyngier@....com,
        pbonzini@...hat.com, rkrcmar@...hat.com, linux@...linux.org.uk,
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Subject: Re: [PATCH V10 07/10] efi: print unrecognized CPER section

Hi Tyler,

On 15/02/17 19:51, Tyler Baicar wrote:
> UEFI spec allows for non-standard section in Common Platform Error
> Record. This is defined in section N.2.3 of UEFI version 2.5.
> 
> Currently if the CPER section's type (UUID) does not match with
> one of the section types that the kernel knows how to parse, the
> section is skipped. Therefore, user is not able to see
> such CPER data, for instance, error record of non-standard section.
> 
> For above mentioned case, this change prints out the raw data in
> hex in dmesg buffer. Data length is taken from Error Data length
> field of Generic Error Data Entry.
> 
> Following is a sample output from dmesg:
> [  115.771702] {1}[Hardware Error]: Hardware error from APEI Generic Hardware Error Source: 2
> [  115.779042] {1}[Hardware Error]: It has been corrected by h/w and requires no further action
> [  115.787456] {1}[Hardware Error]: event severity: corrected
> [  115.792927] {1}[Hardware Error]:  Error 0, type: corrected
> [  115.798415] {1}[Hardware Error]:  fru_id: 00000000-0000-0000-0000-000000000000
> [  115.805596] {1}[Hardware Error]:  fru_text:
> [  115.816105] {1}[Hardware Error]:  section type: d2e2621c-f936-468d-0d84-15a4ed015c8b
> [  115.823880] {1}[Hardware Error]:  section length: 88
> [  115.828779] {1}[Hardware Error]:   00000000: 01000001 00000002 5f434345 525f4543
> [  115.836153] {1}[Hardware Error]:   00000010: 0000574d 00000000 00000000 00000000
> [  115.843531] {1}[Hardware Error]:   00000020: 00000000 00000000 00000000 00000000
> [  115.850908] {1}[Hardware Error]:   00000030: 00000000 00000000 00000000 00000000
> [  115.858288] {1}[Hardware Error]:   00000040: fe800000 00000000 00000004 5f434345
> [  115.865665] {1}[Hardware Error]:   00000050: 525f4543 0000574d

The use-case for this is to capture the data and decode it with a vendor tool?
(if so, please mention that in the commit message!)


> diff --git a/drivers/firmware/efi/cper.c b/drivers/firmware/efi/cper.c
> index c2b0a12..48cb8ee 100644
> --- a/drivers/firmware/efi/cper.c
> +++ b/drivers/firmware/efi/cper.c
> @@ -591,8 +591,16 @@ static void cper_estatus_print_section(
>  			cper_print_proc_arm(newpfx, arm_err);
>  		else
>  			goto err_section_too_small;
> -	} else
> -		printk("%s""section type: unknown, %pUl\n", newpfx, sec_type);

Nit: Its odd that you remove the 'unknown' from this, but we don't get told what
it is, so surely its still unknown.


> +	} else {
> +		const void *unknown_err;
> +
> +		unknown_err = acpi_hest_generic_data_payload(gdata);
> +		printk("%ssection type: %pUl\n", newpfx, sec_type);
> +		printk("%ssection length: %d\n", newpfx,

Nit: please use the "%s""section... that this file consistently uses. This means
this code will still work as expected when someone adds '%ss' support to printk!


> +		       gdata->error_data_length);
> +		print_hex_dump(newpfx, "", DUMP_PREFIX_OFFSET, 16, 4,
> +			       unknown_err, gdata->error_data_length, 0);
> +	}
>  
>  	return;


FWIW:
Reviewed-by: James Morse <james.morse@....com>


Thanks,

James