[PATCH V2] ACPI, APEI: Fixup incorrect 16-bit access width firmware bug

[PATCH V2] ACPI, APEI: Fixup incorrect 16-bit access width firmware bug

[Song liwei]

From: Liwei Song <liwei.song@windriver.com>

This is a follow up to commit f712c71f7b2b ("ACPI, APEI: Fixup common
access width firmware bug") fix the following firmware bug:

[Firmware Bug]: APEI: Invalid bit width + offset in GAR [0xb2/16/0/1/1]

This is due to an 8-bit access width is specified for a 16-bit register,
Rearrange the condition and add 8-bit width check.

Signed-off-by: Liwei Song <liwei.song@windriver.com>
---
 drivers/acpi/apei/apei-base.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/acpi/apei/apei-base.c b/drivers/acpi/apei/apei-base.c
index da370e1..eca3d7a 100644
--- a/drivers/acpi/apei/apei-base.c
+++ b/drivers/acpi/apei/apei-base.c
@@ -604,12 +604,12 @@ static int apei_check_gar(struct acpi_generic_address *reg, u64 *paddr,
 	*access_bit_width = 1UL << (access_size_code + 2);
 
 	/* Fixup common BIOS bug */
-	if (bit_width == 32 && bit_offset == 0 && (*paddr & 0x03) == 0 &&
-	    *access_bit_width < 32)
-		*access_bit_width = 32;
-	else if (bit_width == 64 && bit_offset == 0 && (*paddr & 0x07) == 0 &&
-	    *access_bit_width < 64)
-		*access_bit_width = 64;
+	if (*access_bit_width < bit_width && bit_offset == 0) {
+		if ((bit_width == 16 && (*paddr & 0x01) == 0) ||
+		    (bit_width == 32 && (*paddr & 0x03) == 0) ||
+		    (bit_width == 64 && (*paddr & 0x07) == 0))
+			*access_bit_width = bit_width;
+	}
 
 	if ((bit_width + bit_offset) > *access_bit_width) {
 		pr_warning(FW_BUG APEI_PFX
-- 
2.7.4

RE: [PATCH V2] ACPI, APEI: Fixup incorrect 16-bit access width firmware bug

[Zheng, Lv]

Hi,

> From: linux-acpi-owner@vger.kernel.org [mailto:linux-acpi-owner@vger.kernel.org] On Behalf Of Song
> liwei
> Subject: [PATCH V2] ACPI, APEI: Fixup incorrect 16-bit access width firmware bug
> 
> From: Liwei Song <liwei.song@windriver.com>
> 
> This is a follow up to commit f712c71f7b2b ("ACPI, APEI: Fixup common
> access width firmware bug") fix the following firmware bug:
> 
> [Firmware Bug]: APEI: Invalid bit width + offset in GAR [0xb2/16/0/1/1]
> 
> This is due to an 8-bit access width is specified for a 16-bit register,
> Rearrange the condition and add 8-bit width check.
> 
> Signed-off-by: Liwei Song <liwei.song@windriver.com>
> ---
>  drivers/acpi/apei/apei-base.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/acpi/apei/apei-base.c b/drivers/acpi/apei/apei-base.c
> index da370e1..eca3d7a 100644
> --- a/drivers/acpi/apei/apei-base.c
> +++ b/drivers/acpi/apei/apei-base.c
> @@ -604,12 +604,12 @@ static int apei_check_gar(struct acpi_generic_address *reg, u64 *paddr,
>  	*access_bit_width = 1UL << (access_size_code + 2);
> 
>  	/* Fixup common BIOS bug */
> -	if (bit_width == 32 && bit_offset == 0 && (*paddr & 0x03) == 0 &&
> -	    *access_bit_width < 32)
> -		*access_bit_width = 32;
> -	else if (bit_width == 64 && bit_offset == 0 && (*paddr & 0x07) == 0 &&
> -	    *access_bit_width < 64)
> -		*access_bit_width = 64;
> +	if (*access_bit_width < bit_width && bit_offset == 0) {
> +		if ((bit_width == 16 && (*paddr & 0x01) == 0) ||
> +		    (bit_width == 32 && (*paddr & 0x03) == 0) ||
> +		    (bit_width == 64 && (*paddr & 0x07) == 0))
> +			*access_bit_width = bit_width;
> +	}
> 
>  	if ((bit_width + bit_offset) > *access_bit_width) {
>  		pr_warning(FW_BUG APEI_PFX

IMO, such problem could also be fixed by this commit and a cleanup of APEI
GAR code to invoke generic ACPICA GAR API - acpi_read()/acpi_write() directly.
https://github.com/acpica/acpica/pull/209

Thanks and best regards
Lv

Re: [PATCH V2] ACPI, APEI: Fixup incorrect 16-bit access width firmware bug

[Liwei Song]

On 07/31/2017 10:09 AM, Zheng, Lv wrote:
> Hi,
> 
>> From: linux-acpi-owner@vger.kernel.org [mailto:linux-acpi-owner@vger.kernel.org] On Behalf Of Song
>> liwei
>> Subject: [PATCH V2] ACPI, APEI: Fixup incorrect 16-bit access width firmware bug
>>
>> From: Liwei Song <liwei.song@windriver.com>
>>
>> This is a follow up to commit f712c71f7b2b ("ACPI, APEI: Fixup common
>> access width firmware bug") fix the following firmware bug:
>>
>> [Firmware Bug]: APEI: Invalid bit width + offset in GAR [0xb2/16/0/1/1]
>>
>> This is due to an 8-bit access width is specified for a 16-bit register,
>> Rearrange the condition and add 8-bit width check.
>>
>> Signed-off-by: Liwei Song <liwei.song@windriver.com>
>> ---
>>  drivers/acpi/apei/apei-base.c | 12 ++++++------
>>  1 file changed, 6 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/acpi/apei/apei-base.c b/drivers/acpi/apei/apei-base.c
>> index da370e1..eca3d7a 100644
>> --- a/drivers/acpi/apei/apei-base.c
>> +++ b/drivers/acpi/apei/apei-base.c
>> @@ -604,12 +604,12 @@ static int apei_check_gar(struct acpi_generic_address *reg, u64 *paddr,
>>  	*access_bit_width = 1UL << (access_size_code + 2);
>>
>>  	/* Fixup common BIOS bug */
>> -	if (bit_width == 32 && bit_offset == 0 && (*paddr & 0x03) == 0 &&
>> -	    *access_bit_width < 32)
>> -		*access_bit_width = 32;
>> -	else if (bit_width == 64 && bit_offset == 0 && (*paddr & 0x07) == 0 &&
>> -	    *access_bit_width < 64)
>> -		*access_bit_width = 64;
>> +	if (*access_bit_width < bit_width && bit_offset == 0) {
>> +		if ((bit_width == 16 && (*paddr & 0x01) == 0) ||
>> +		    (bit_width == 32 && (*paddr & 0x03) == 0) ||
>> +		    (bit_width == 64 && (*paddr & 0x07) == 0))
>> +			*access_bit_width = bit_width;
>> +	}
>>
>>  	if ((bit_width + bit_offset) > *access_bit_width) {
>>  		pr_warning(FW_BUG APEI_PFX
> 
> IMO, such problem could also be fixed by this commit and a cleanup of APEI
> GAR code to invoke generic ACPICA GAR API - acpi_read()/acpi_write() directly.
> https://github.com/acpica/acpica/pull/209

Hi Lv,

I'm a bit confuse about the commit you said, do you mean this commit can also fix
this common 16-bit access width error, and will check-in to upstream kernel latter?
If so, please ignore this review.

Thanks,
Liwei.


> 
> Thanks and best regards
> Lv
> 
> 
>