[v3,2/2] ACPI/PPTT: Handle architecturally unknown cache types
diff mbox series

Message ID 1538103477-15513-3-git-send-email-jhugo@codeaurora.org
State Superseded
Headers show
Series
  • PPTT handle Handle architecturally unknown cache types
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Commit Message

Jeffrey Hugo Sept. 28, 2018, 2:57 a.m. UTC
The type of a cache might not be specified by architectural mechanisms (ie
system registers), but its type might be specified in the PPTT.  In this
case, we should populate the type of the cache, rather than leave it
undefined.

This fixes the issue where the cacheinfo driver will not populate sysfs
for such caches, resulting in the information missing from utilities like
lstopo and lscpu, thus degrading the user experience.

Fixes: 2bd00bcd73e5 (ACPI/PPTT: Add Processor Properties Topology Table parsing)
Reported-by: Vijaya Kumar K <vkilari@codeaurora.org>
Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>
---
 drivers/acpi/pptt.c | 30 +++++++++++++-----------------
 1 file changed, 13 insertions(+), 17 deletions(-)

Comments

Jeremy Linton Sept. 28, 2018, 9:52 p.m. UTC | #1
Hi,

On 09/27/2018 09:57 PM, Jeffrey Hugo wrote:
> The type of a cache might not be specified by architectural mechanisms (ie
> system registers), but its type might be specified in the PPTT.  In this
> case, we should populate the type of the cache, rather than leave it
> undefined. 
> 
> This fixes the issue where the cacheinfo driver will not populate sysfs
> for such caches, resulting in the information missing from utilities like
> lstopo and lscpu, thus degrading the user experience.

The code looks fine to me.

Reviewed-by: Jeremy Linton <jeremy.linton@arm.com>

Thanks!

> 
> Fixes: 2bd00bcd73e5 (ACPI/PPTT: Add Processor Properties Topology Table parsing)
> Reported-by: Vijaya Kumar K <vkilari@codeaurora.org>

PS:

Although, if you end up re-spinning this, I think its appropriate to add 
in the commit message that what this is really working around is 
firmware that has declined to fill out all the fields in the cache 
description.


> Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>
> ---
>   drivers/acpi/pptt.c | 30 +++++++++++++-----------------
>   1 file changed, 13 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c
> index d1e26cb..38ac30e 100644
> --- a/drivers/acpi/pptt.c
> +++ b/drivers/acpi/pptt.c
> @@ -357,25 +357,15 @@ static void update_cache_properties(struct cacheinfo *this_leaf,
>   				    struct acpi_pptt_cache *found_cache,
>   				    struct acpi_pptt_processor *cpu_node)
>   {
> -	int valid_flags = 0;
> -
>   	this_leaf->fw_token = cpu_node;
> -	if (found_cache->flags & ACPI_PPTT_SIZE_PROPERTY_VALID) {
> +	if (found_cache->flags & ACPI_PPTT_SIZE_PROPERTY_VALID)
>   		this_leaf->size = found_cache->size;
> -		valid_flags++;
> -	}
> -	if (found_cache->flags & ACPI_PPTT_LINE_SIZE_VALID) {
> +	if (found_cache->flags & ACPI_PPTT_LINE_SIZE_VALID)
>   		this_leaf->coherency_line_size = found_cache->line_size;
> -		valid_flags++;
> -	}
> -	if (found_cache->flags & ACPI_PPTT_NUMBER_OF_SETS_VALID) {
> +	if (found_cache->flags & ACPI_PPTT_NUMBER_OF_SETS_VALID)
>   		this_leaf->number_of_sets = found_cache->number_of_sets;
> -		valid_flags++;
> -	}
> -	if (found_cache->flags & ACPI_PPTT_ASSOCIATIVITY_VALID) {
> +	if (found_cache->flags & ACPI_PPTT_ASSOCIATIVITY_VALID)
>   		this_leaf->ways_of_associativity = found_cache->associativity;
> -		valid_flags++;
> -	}
>   	if (found_cache->flags & ACPI_PPTT_WRITE_POLICY_VALID) {
>   		switch (found_cache->attributes & ACPI_PPTT_MASK_WRITE_POLICY) {
>   		case ACPI_PPTT_CACHE_POLICY_WT:
> @@ -402,11 +392,17 @@ static void update_cache_properties(struct cacheinfo *this_leaf,
>   		}
>   	}
>   	/*
> -	 * If the above flags are valid, and the cache type is NOCACHE
> -	 * update the cache type as well.
> +	 * If cache type is NOCACHE, then the cache hasn't been specified
> +	 * via other mechanisms.  Update the type if a cache type has been
> +	 * provided.
> +	 *
> +	 * Note, we assume such caches are unified based on conventional system
> +	 * design and known examples.  Significant work is required elsewhere to
> +	 * fully support data/instruction only type caches which are only
> +	 * specified in PPTT.
>   	 */
>   	if (this_leaf->type == CACHE_TYPE_NOCACHE &&
> -	    valid_flags == PPTT_CHECKED_ATTRIBUTES)
> +	    found_cache->flags & ACPI_PPTT_CACHE_TYPE_VALID)
>   		this_leaf->type = CACHE_TYPE_UNIFIED;
>   }
>   
>
Sudeep Holla Oct. 2, 2018, 10:57 a.m. UTC | #2
On Thu, Sep 27, 2018 at 08:57:57PM -0600, Jeffrey Hugo wrote:
> The type of a cache might not be specified by architectural mechanisms (ie
> system registers), but its type might be specified in the PPTT.  In this
> case, we should populate the type of the cache, rather than leave it
> undefined.
> 
> This fixes the issue where the cacheinfo driver will not populate sysfs
> for such caches, resulting in the information missing from utilities like
> lstopo and lscpu, thus degrading the user experience.
> 
> Fixes: 2bd00bcd73e5 (ACPI/PPTT: Add Processor Properties Topology Table parsing)
> Reported-by: Vijaya Kumar K <vkilari@codeaurora.org>
> Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>
> ---
>  drivers/acpi/pptt.c | 30 +++++++++++++-----------------
>  1 file changed, 13 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c
> index d1e26cb..38ac30e 100644
> --- a/drivers/acpi/pptt.c
> +++ b/drivers/acpi/pptt.c
> @@ -357,25 +357,15 @@ static void update_cache_properties(struct cacheinfo *this_leaf,
>  				    struct acpi_pptt_cache *found_cache,
>  				    struct acpi_pptt_processor *cpu_node)
>  {
> -	int valid_flags = 0;
> -
>  	this_leaf->fw_token = cpu_node;
> -	if (found_cache->flags & ACPI_PPTT_SIZE_PROPERTY_VALID) {
> +	if (found_cache->flags & ACPI_PPTT_SIZE_PROPERTY_VALID)
>  		this_leaf->size = found_cache->size;
> -		valid_flags++;
> -	}
> -	if (found_cache->flags & ACPI_PPTT_LINE_SIZE_VALID) {
> +	if (found_cache->flags & ACPI_PPTT_LINE_SIZE_VALID)
>  		this_leaf->coherency_line_size = found_cache->line_size;
> -		valid_flags++;
> -	}
> -	if (found_cache->flags & ACPI_PPTT_NUMBER_OF_SETS_VALID) {
> +	if (found_cache->flags & ACPI_PPTT_NUMBER_OF_SETS_VALID)
>  		this_leaf->number_of_sets = found_cache->number_of_sets;
> -		valid_flags++;
> -	}
> -	if (found_cache->flags & ACPI_PPTT_ASSOCIATIVITY_VALID) {
> +	if (found_cache->flags & ACPI_PPTT_ASSOCIATIVITY_VALID)
>  		this_leaf->ways_of_associativity = found_cache->associativity;
> -		valid_flags++;
> -	}
>  	if (found_cache->flags & ACPI_PPTT_WRITE_POLICY_VALID) {
>  		switch (found_cache->attributes & ACPI_PPTT_MASK_WRITE_POLICY) {
>  		case ACPI_PPTT_CACHE_POLICY_WT:
> @@ -402,11 +392,17 @@ static void update_cache_properties(struct cacheinfo *this_leaf,
>  		}
>  	}
>  	/*
> -	 * If the above flags are valid, and the cache type is NOCACHE
> -	 * update the cache type as well.
> +	 * If cache type is NOCACHE, then the cache hasn't been specified
> +	 * via other mechanisms.  Update the type if a cache type has been
> +	 * provided.
> +	 *
> +	 * Note, we assume such caches are unified based on conventional system
> +	 * design and known examples.  Significant work is required elsewhere to
> +	 * fully support data/instruction only type caches which are only
> +	 * specified in PPTT.
>  	 */
>  	if (this_leaf->type == CACHE_TYPE_NOCACHE &&
> -	    valid_flags == PPTT_CHECKED_ATTRIBUTES)

I don't think we use PPTT_CHECKED_ATTRIBUTES elsewhere.
If so, can we drop that ?

Other than that:
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>

--
Regards,
Sudeep
Jeffrey Hugo Oct. 2, 2018, 3:30 p.m. UTC | #3
On 10/2/2018 4:57 AM, Sudeep Holla wrote:
> On Thu, Sep 27, 2018 at 08:57:57PM -0600, Jeffrey Hugo wrote:
>> The type of a cache might not be specified by architectural mechanisms (ie
>> system registers), but its type might be specified in the PPTT.  In this
>> case, we should populate the type of the cache, rather than leave it
>> undefined.
>>
>> This fixes the issue where the cacheinfo driver will not populate sysfs
>> for such caches, resulting in the information missing from utilities like
>> lstopo and lscpu, thus degrading the user experience.
>>
>> Fixes: 2bd00bcd73e5 (ACPI/PPTT: Add Processor Properties Topology Table parsing)
>> Reported-by: Vijaya Kumar K <vkilari@codeaurora.org>
>> Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>
>> ---
>>   drivers/acpi/pptt.c | 30 +++++++++++++-----------------
>>   1 file changed, 13 insertions(+), 17 deletions(-)
>>
>> diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c
>> index d1e26cb..38ac30e 100644
>> --- a/drivers/acpi/pptt.c
>> +++ b/drivers/acpi/pptt.c
>> @@ -357,25 +357,15 @@ static void update_cache_properties(struct cacheinfo *this_leaf,
>>   				    struct acpi_pptt_cache *found_cache,
>>   				    struct acpi_pptt_processor *cpu_node)
>>   {
>> -	int valid_flags = 0;
>> -
>>   	this_leaf->fw_token = cpu_node;
>> -	if (found_cache->flags & ACPI_PPTT_SIZE_PROPERTY_VALID) {
>> +	if (found_cache->flags & ACPI_PPTT_SIZE_PROPERTY_VALID)
>>   		this_leaf->size = found_cache->size;
>> -		valid_flags++;
>> -	}
>> -	if (found_cache->flags & ACPI_PPTT_LINE_SIZE_VALID) {
>> +	if (found_cache->flags & ACPI_PPTT_LINE_SIZE_VALID)
>>   		this_leaf->coherency_line_size = found_cache->line_size;
>> -		valid_flags++;
>> -	}
>> -	if (found_cache->flags & ACPI_PPTT_NUMBER_OF_SETS_VALID) {
>> +	if (found_cache->flags & ACPI_PPTT_NUMBER_OF_SETS_VALID)
>>   		this_leaf->number_of_sets = found_cache->number_of_sets;
>> -		valid_flags++;
>> -	}
>> -	if (found_cache->flags & ACPI_PPTT_ASSOCIATIVITY_VALID) {
>> +	if (found_cache->flags & ACPI_PPTT_ASSOCIATIVITY_VALID)
>>   		this_leaf->ways_of_associativity = found_cache->associativity;
>> -		valid_flags++;
>> -	}
>>   	if (found_cache->flags & ACPI_PPTT_WRITE_POLICY_VALID) {
>>   		switch (found_cache->attributes & ACPI_PPTT_MASK_WRITE_POLICY) {
>>   		case ACPI_PPTT_CACHE_POLICY_WT:
>> @@ -402,11 +392,17 @@ static void update_cache_properties(struct cacheinfo *this_leaf,
>>   		}
>>   	}
>>   	/*
>> -	 * If the above flags are valid, and the cache type is NOCACHE
>> -	 * update the cache type as well.
>> +	 * If cache type is NOCACHE, then the cache hasn't been specified
>> +	 * via other mechanisms.  Update the type if a cache type has been
>> +	 * provided.
>> +	 *
>> +	 * Note, we assume such caches are unified based on conventional system
>> +	 * design and known examples.  Significant work is required elsewhere to
>> +	 * fully support data/instruction only type caches which are only
>> +	 * specified in PPTT.
>>   	 */
>>   	if (this_leaf->type == CACHE_TYPE_NOCACHE &&
>> -	    valid_flags == PPTT_CHECKED_ATTRIBUTES)
> 
> I don't think we use PPTT_CHECKED_ATTRIBUTES elsewhere.
> If so, can we drop that ?
> 
> Other than that:
> Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>

Whoops, you are right.  For some reason I thought that came from the 
standard ACPICA definitions.  Let me drop that.

Patch
diff mbox series

diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c
index d1e26cb..38ac30e 100644
--- a/drivers/acpi/pptt.c
+++ b/drivers/acpi/pptt.c
@@ -357,25 +357,15 @@  static void update_cache_properties(struct cacheinfo *this_leaf,
 				    struct acpi_pptt_cache *found_cache,
 				    struct acpi_pptt_processor *cpu_node)
 {
-	int valid_flags = 0;
-
 	this_leaf->fw_token = cpu_node;
-	if (found_cache->flags & ACPI_PPTT_SIZE_PROPERTY_VALID) {
+	if (found_cache->flags & ACPI_PPTT_SIZE_PROPERTY_VALID)
 		this_leaf->size = found_cache->size;
-		valid_flags++;
-	}
-	if (found_cache->flags & ACPI_PPTT_LINE_SIZE_VALID) {
+	if (found_cache->flags & ACPI_PPTT_LINE_SIZE_VALID)
 		this_leaf->coherency_line_size = found_cache->line_size;
-		valid_flags++;
-	}
-	if (found_cache->flags & ACPI_PPTT_NUMBER_OF_SETS_VALID) {
+	if (found_cache->flags & ACPI_PPTT_NUMBER_OF_SETS_VALID)
 		this_leaf->number_of_sets = found_cache->number_of_sets;
-		valid_flags++;
-	}
-	if (found_cache->flags & ACPI_PPTT_ASSOCIATIVITY_VALID) {
+	if (found_cache->flags & ACPI_PPTT_ASSOCIATIVITY_VALID)
 		this_leaf->ways_of_associativity = found_cache->associativity;
-		valid_flags++;
-	}
 	if (found_cache->flags & ACPI_PPTT_WRITE_POLICY_VALID) {
 		switch (found_cache->attributes & ACPI_PPTT_MASK_WRITE_POLICY) {
 		case ACPI_PPTT_CACHE_POLICY_WT:
@@ -402,11 +392,17 @@  static void update_cache_properties(struct cacheinfo *this_leaf,
 		}
 	}
 	/*
-	 * If the above flags are valid, and the cache type is NOCACHE
-	 * update the cache type as well.
+	 * If cache type is NOCACHE, then the cache hasn't been specified
+	 * via other mechanisms.  Update the type if a cache type has been
+	 * provided.
+	 *
+	 * Note, we assume such caches are unified based on conventional system
+	 * design and known examples.  Significant work is required elsewhere to
+	 * fully support data/instruction only type caches which are only
+	 * specified in PPTT.
 	 */
 	if (this_leaf->type == CACHE_TYPE_NOCACHE &&
-	    valid_flags == PPTT_CHECKED_ATTRIBUTES)
+	    found_cache->flags & ACPI_PPTT_CACHE_TYPE_VALID)
 		this_leaf->type = CACHE_TYPE_UNIFIED;
 }