[PATCH v3 0/2] PPTT handle Handle architecturally unknown cache types

[PATCH v3 0/2] PPTT handle Handle architecturally unknown cache types

[Jeffrey Hugo]

The ARM Architecture Reference Manual allows for caches to be "invisible" and
thus not specified in the system registers under some scenarios such as if the
cache cannot be managed by set/way operations.

However, such caches may be specified in the ACPI PPTT table for workload
performance/scheduling optimizations.

Currently such caches can cause an error in lscpu -

lscpu: cannot open /sys/devices/system/cpu/cpu0/cache/index3/type: No such
file or directory

and result in no output, providing a poor user experience.  lstopo is also
affected as such caches are not included in the output.

Address these issues by attempting to be a little more discerning about when
cache information is provided to userspace, and also utilize all sources for
cache information when possible.

[v3]
-removed valid flag in PPTT
-Added Jeremy Linton's reviewed-by

[v2]
-Updated cacheinfo per Sudeep's suggestion
-Integrated the PPTT fix into existing PPTT code per Sudeep's suggestion

Jeffrey Hugo (2):
  drivers: base: cacheinfo: Do not populate sysfs for unknown cache
    types
  ACPI/PPTT: Handle architecturally unknown cache types

 drivers/acpi/pptt.c      | 15 +++++++++++----
 drivers/base/cacheinfo.c |  2 ++
 2 files changed, 13 insertions(+), 4 deletions(-)

-- 
Qualcomm Datacenter Technologies as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.

[PATCH v3 1/2] drivers: base: cacheinfo: Do not populate sysfs for unknown cache types

[Jeffrey Hugo]

If a cache has an unknown type because neither the hardware nor the
firmware told us, an entry in the sysfs tree will be made, but the type
file will not be present.  lscpu depends on the type file being present
for every entry, and will error out without printing system information
if lscpu cannot open the type file.

Presenting information about a cache without indicating its type is not
useful, therefore if we hit a cache with an unknown type, stop populating
sysfs so that userspace has the maximum amount of useful information.

This addresses the following lscpu error, which prevents any output.
lscpu: cannot open /sys/devices/system/cpu/cpu0/cache/index3/type: No such
file or directory

Suggested-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>
Reviewed-by: Jeremy Linton <jeremy.linton@arm.com>
---
 drivers/base/cacheinfo.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c
index 5d5b598..cf78fa6 100644
--- a/drivers/base/cacheinfo.c
+++ b/drivers/base/cacheinfo.c
@@ -615,6 +615,8 @@ static int cache_add_dev(unsigned int cpu)
 		this_leaf = this_cpu_ci->info_list + i;
 		if (this_leaf->disable_sysfs)
 			continue;
+		if (this_leaf->type == CACHE_TYPE_NOCACHE)
+			break;
 		cache_groups = cache_get_attribute_groups(this_leaf);
 		ci_dev = cpu_device_create(parent, this_leaf, cache_groups,
 					   "index%1u", i);
-- 
Qualcomm Datacenter Technologies as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.

Re: [PATCH v3 1/2] drivers: base: cacheinfo: Do not populate sysfs for unknown cache types

[Sudeep Holla]

On Thu, Sep 27, 2018 at 08:57:56PM -0600, Jeffrey Hugo wrote:
> If a cache has an unknown type because neither the hardware nor the
> firmware told us, an entry in the sysfs tree will be made, but the type
> file will not be present.  lscpu depends on the type file being present
> for every entry, and will error out without printing system information
> if lscpu cannot open the type file.
> 
> Presenting information about a cache without indicating its type is not
> useful, therefore if we hit a cache with an unknown type, stop populating
> sysfs so that userspace has the maximum amount of useful information.
> 
> This addresses the following lscpu error, which prevents any output.
> lscpu: cannot open /sys/devices/system/cpu/cpu0/cache/index3/type: No such
> file or directory
> 
> Suggested-by: Sudeep Holla <sudeep.holla@arm.com>
> Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>
> Reviewed-by: Jeremy Linton <jeremy.linton@arm.com>

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

--
Regards,
Sudeep

Re: [PATCH v3 1/2] drivers: base: cacheinfo: Do not populate sysfs for unknown cache types

[Rafael J. Wysocki]

On Friday, September 28, 2018 4:57:56 AM CEST Jeffrey Hugo wrote:
> If a cache has an unknown type because neither the hardware nor the
> firmware told us, an entry in the sysfs tree will be made, but the type
> file will not be present.  lscpu depends on the type file being present
> for every entry, and will error out without printing system information
> if lscpu cannot open the type file.
> 
> Presenting information about a cache without indicating its type is not
> useful, therefore if we hit a cache with an unknown type, stop populating
> sysfs so that userspace has the maximum amount of useful information.
> 
> This addresses the following lscpu error, which prevents any output.
> lscpu: cannot open /sys/devices/system/cpu/cpu0/cache/index3/type: No such
> file or directory
> 
> Suggested-by: Sudeep Holla <sudeep.holla@arm.com>
> Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>
> Reviewed-by: Jeremy Linton <jeremy.linton@arm.com>
> ---
>  drivers/base/cacheinfo.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c
> index 5d5b598..cf78fa6 100644
> --- a/drivers/base/cacheinfo.c
> +++ b/drivers/base/cacheinfo.c
> @@ -615,6 +615,8 @@ static int cache_add_dev(unsigned int cpu)
>  		this_leaf = this_cpu_ci->info_list + i;
>  		if (this_leaf->disable_sysfs)
>  			continue;
> +		if (this_leaf->type == CACHE_TYPE_NOCACHE)
> +			break;
>  		cache_groups = cache_get_attribute_groups(this_leaf);
>  		ci_dev = cpu_device_create(parent, this_leaf, cache_groups,
>  					   "index%1u", i);
> 

Can you please resend this patch with all tags collected so far?

Patchwork doesn't seem to have picked it up.

Thanks,
Rafael

Re: [PATCH v3 1/2] drivers: base: cacheinfo: Do not populate sysfs for unknown cache types

[Jeffrey Hugo]

On 10/3/2018 3:35 AM, Rafael J. Wysocki wrote:
> On Friday, September 28, 2018 4:57:56 AM CEST Jeffrey Hugo wrote:
>> If a cache has an unknown type because neither the hardware nor the
>> firmware told us, an entry in the sysfs tree will be made, but the type
>> file will not be present.  lscpu depends on the type file being present
>> for every entry, and will error out without printing system information
>> if lscpu cannot open the type file.
>>
>> Presenting information about a cache without indicating its type is not
>> useful, therefore if we hit a cache with an unknown type, stop populating
>> sysfs so that userspace has the maximum amount of useful information.
>>
>> This addresses the following lscpu error, which prevents any output.
>> lscpu: cannot open /sys/devices/system/cpu/cpu0/cache/index3/type: No such
>> file or directory
>>
>> Suggested-by: Sudeep Holla <sudeep.holla@arm.com>
>> Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>
>> Reviewed-by: Jeremy Linton <jeremy.linton@arm.com>
>> ---
>>   drivers/base/cacheinfo.c | 2 ++
>>   1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c
>> index 5d5b598..cf78fa6 100644
>> --- a/drivers/base/cacheinfo.c
>> +++ b/drivers/base/cacheinfo.c
>> @@ -615,6 +615,8 @@ static int cache_add_dev(unsigned int cpu)
>>   		this_leaf = this_cpu_ci->info_list + i;
>>   		if (this_leaf->disable_sysfs)
>>   			continue;
>> +		if (this_leaf->type == CACHE_TYPE_NOCACHE)
>> +			break;
>>   		cache_groups = cache_get_attribute_groups(this_leaf);
>>   		ci_dev = cpu_device_create(parent, this_leaf, cache_groups,
>>   					   "index%1u", i);
>>
> 
> Can you please resend this patch with all tags collected so far?

Will do.

-- 
Jeffrey Hugo
Qualcomm Datacenter Technologies as an affiliate of Qualcomm 
Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.

[PATCH v3 2/2] ACPI/PPTT: Handle architecturally unknown cache types

[Jeffrey Hugo]

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)
+	    found_cache->flags & ACPI_PPTT_CACHE_TYPE_VALID)
 		this_leaf->type = CACHE_TYPE_UNIFIED;
 }
 
-- 
Qualcomm Datacenter Technologies as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.

Re: [PATCH v3 2/2] ACPI/PPTT: Handle architecturally unknown cache types

[Jeremy Linton]

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;
>   }
>   
> 

Re: [PATCH v3 2/2] ACPI/PPTT: Handle architecturally unknown cache types

[Sudeep Holla]

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

Re: [PATCH v3 2/2] ACPI/PPTT: Handle architecturally unknown cache types

[Jeffrey Hugo]

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.

-- 
Jeffrey Hugo
Qualcomm Datacenter Technologies as an affiliate of Qualcomm 
Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.