linux-kernel - Re: [PATCH 1/7] apei, mce: Call MCE-specific code only for X86 architecture.

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Date:	Mon, 05 May 2014 16:34:41 +0200
From:	Tomasz Nowicki <tomasz.nowicki@...aro.org>
To:	Borislav Petkov <bp@...en8.de>
CC:	rjw@...ysocki.net, lenb@...nel.org, tony.luck@...el.com,
	bp@...e.de, m.chehab@...sung.com, linux-edac@...r.kernel.org,
	x86@...nel.org, linux-acpi@...r.kernel.org,
	linux-kernel@...r.kernel.org, linaro-acpi@...ts.linaro.org
Subject: Re: [PATCH 1/7] apei, mce: Call MCE-specific code only for X86 architecture.

On 05.05.2014 13:44, Borislav Petkov wrote:
> On Wed, Apr 09, 2014 at 05:14:29PM +0200, Tomasz Nowicki wrote:
>> This commit is dealing with MCE code in:
>> - hest.c
>> Move acpi_disable_cmcff flag to hest_parse_cmc() and makes
>> that depend on CONFIG_X86_MCE so that we do not have to maintain
>> acpi_disable_cmcff for architectures which do not support MCE.
>> Also, wrap architectural MCE header inside #ifdef CONFIG_X86_MCE.
>>
>> - ghes.c
>> Wrap architectural MCE header inside #ifdef CONFIG_X86_MCE similar to rest
>> of the MCE code in this file.
>>
>> Signed-off-by: Tomasz Nowicki <tomasz.nowicki@...aro.org>
>> ---
>>   drivers/acpi/apei/ghes.c |    2 ++
>>   drivers/acpi/apei/hest.c |    8 ++++++--
>>   2 files changed, 8 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
>> index dab7cb7..f7edffc 100644
>> --- a/drivers/acpi/apei/ghes.c
>> +++ b/drivers/acpi/apei/ghes.c
>> @@ -49,7 +49,9 @@
>>   #include <linux/aer.h>
>>
>>   #include <acpi/ghes.h>
>> +#ifdef CONFIG_X86_MCE
>>   #include <asm/mce.h>
>> +#endif
>>   #include <asm/tlbflush.h>
>>   #include <asm/nmi.h>
>>
>> diff --git a/drivers/acpi/apei/hest.c b/drivers/acpi/apei/hest.c
>> index f5e37f3..98db702 100644
>> --- a/drivers/acpi/apei/hest.c
>> +++ b/drivers/acpi/apei/hest.c
>> @@ -36,7 +36,9 @@
>>   #include <linux/io.h>
>>   #include <linux/platform_device.h>
>>   #include <acpi/apei.h>
>> +#ifdef CONFIG_X86_MCE
>>   #include <asm/mce.h>
>> +#endif
>
> Actually, I would prefer if you wrapped all the arch-specific calls into
> arch-specific functions, say, convert
>
> apei_mce_report_mem_error -> apei_arch_report_mem_error
>
> and have default empty functions for arches which don't use that
> functionality.
>
> This way you can save yourself the ugly ifdeffery around the place.
>
True, this can be improved as you suggested.

>>
>>   #include "apei-internal.h"
>>
>> @@ -133,6 +135,9 @@ static int __init hest_parse_cmc(struct acpi_hest_header *hest_hdr, void *data)
>>   	struct acpi_hest_ia_corrected *cmc;
>>   	struct acpi_hest_ia_error_bank *mc_bank;
>>
>> +	if (acpi_disable_cmcff)
>> +		return 1;
>
> This could be
>
> 	if (arch_disable_cmcff())
> 		return 1;
>
> with the default stub being
>
> static inline bool arch_disable_cmcff(void)
> {
> 	return false;
> }
>
> and so on, like it is done in many other places in the kernel.

acpi_disable_cmcff as global value can switch off/on MC entries 
analysing via kernel args. This glob value resides in x86 ACPI code and 
has meaning only for MCE related mechanism, that is why I have moved it 
under hest_parse_cmc.

Thanks.

Tomasz
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