In actbl2.h, acpi_pptt_cache describes the fields in the original
Cache Type Structure. In PPTT table version 3 a new field was added at the
end, cache_id. This is described in acpi_pptt_cache_v1 but rather than
including all v1 fields it just includes this one.
In lieu of this being fixed in acpica, introduce acpi_pptt_cache_v1_full to
contain all the fields of the Cache Type Structure . Update the existing
code to use this new struct. This simplifies the code and removes a
non-standard use of ACPI_ADD_PTR.
Signed-off-by: Ben Horgan <ben.horgan@arm.com>
---
I have opened a pull request to acpica to update acpi_pptt_cache_v1 to
include all fields. https://github.com/acpica/acpica/pull/1059
Change since v4:
Use fields directly in acpi_pptt_cache_v1_full
Delay the casting
Changes since v3:
New patch
---
drivers/acpi/pptt.c | 47 +++++++++++++++++++++++++++++++++++----------
1 file changed, 37 insertions(+), 10 deletions(-)
diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c
index 2856254e29d7..53fde9bd8140 100644
--- a/drivers/acpi/pptt.c
+++ b/drivers/acpi/pptt.c
@@ -21,6 +21,25 @@
#include <linux/cacheinfo.h>
#include <acpi/processor.h>
+/*
+ * The acpi_pptt_cache_v1 in actbl2.h, which is imported from acpica,
+ * only contains the cache_id field rather than all the fields of the
+ * Cache Type Structure. Use this alternative structure until it is
+ * resolved in acpica.
+ */
+struct acpi_pptt_cache_v1_full {
+ struct acpi_subtable_header header;
+ u16 reserved;
+ u32 flags;
+ u32 next_level_of_cache;
+ u32 size;
+ u32 number_of_sets;
+ u8 associativity;
+ u8 attributes;
+ u16 line_size;
+ u32 cache_id;
+};
+
static struct acpi_subtable_header *fetch_pptt_subtable(struct acpi_table_header *table_hdr,
u32 pptt_ref)
{
@@ -56,6 +75,18 @@ static struct acpi_pptt_cache *fetch_pptt_cache(struct acpi_table_header *table_
return (struct acpi_pptt_cache *)fetch_pptt_subtable(table_hdr, pptt_ref);
}
+static struct acpi_pptt_cache_v1_full *upgrade_pptt_cache(struct acpi_pptt_cache *cache)
+{
+ if (cache->header.length < sizeof(struct acpi_pptt_cache_v1_full))
+ return NULL;
+
+ /* No use for v1 if the only additional field is invalid */
+ if (!(cache->flags & ACPI_PPTT_CACHE_ID_VALID))
+ return NULL;
+
+ return (struct acpi_pptt_cache_v1_full *)cache;
+}
+
static struct acpi_subtable_header *acpi_get_pptt_resource(struct acpi_table_header *table_hdr,
struct acpi_pptt_processor *node,
int resource)
@@ -111,7 +142,7 @@ static unsigned int acpi_pptt_walk_cache(struct acpi_table_header *table_hdr,
if (res->type != ACPI_PPTT_TYPE_CACHE)
return 0;
- cache = (struct acpi_pptt_cache *) res;
+ cache = (struct acpi_pptt_cache *)res;
while (cache) {
local_level++;
@@ -355,7 +386,6 @@ static struct acpi_pptt_cache *acpi_find_cache_node(struct acpi_table_header *ta
* @this_leaf: Kernel cache info structure being updated
* @found_cache: The PPTT node describing this cache instance
* @cpu_node: A unique reference to describe this cache instance
- * @revision: The revision of the PPTT table
*
* The ACPI spec implies that the fields in the cache structures are used to
* extend and correct the information probed from the hardware. Lets only
@@ -365,10 +395,9 @@ static struct acpi_pptt_cache *acpi_find_cache_node(struct acpi_table_header *ta
*/
static void update_cache_properties(struct cacheinfo *this_leaf,
struct acpi_pptt_cache *found_cache,
- struct acpi_pptt_processor *cpu_node,
- u8 revision)
+ struct acpi_pptt_processor *cpu_node)
{
- struct acpi_pptt_cache_v1* found_cache_v1;
+ struct acpi_pptt_cache_v1_full *found_cache_v1;
this_leaf->fw_token = cpu_node;
if (found_cache->flags & ACPI_PPTT_SIZE_PROPERTY_VALID)
@@ -418,9 +447,8 @@ static void update_cache_properties(struct cacheinfo *this_leaf,
found_cache->flags & ACPI_PPTT_CACHE_TYPE_VALID)
this_leaf->type = CACHE_TYPE_UNIFIED;
- if (revision >= 3 && (found_cache->flags & ACPI_PPTT_CACHE_ID_VALID)) {
- found_cache_v1 = ACPI_ADD_PTR(struct acpi_pptt_cache_v1,
- found_cache, sizeof(struct acpi_pptt_cache));
+ found_cache_v1 = upgrade_pptt_cache(found_cache);
+ if (found_cache_v1) {
this_leaf->id = found_cache_v1->cache_id;
this_leaf->attributes |= CACHE_ID;
}
@@ -445,8 +473,7 @@ static void cache_setup_acpi_cpu(struct acpi_table_header *table,
pr_debug("found = %p %p\n", found_cache, cpu_node);
if (found_cache)
update_cache_properties(this_leaf, found_cache,
- ACPI_TO_POINTER(ACPI_PTR_DIFF(cpu_node, table)),
- table->revision);
+ ACPI_TO_POINTER(ACPI_PTR_DIFF(cpu_node, table)));
index++;
}
--
2.43.0On 11/17/25 10:59 AM, Ben Horgan wrote:
> In actbl2.h, acpi_pptt_cache describes the fields in the original
> Cache Type Structure. In PPTT table version 3 a new field was added at the
> end, cache_id. This is described in acpi_pptt_cache_v1 but rather than
> including all v1 fields it just includes this one.
>
> In lieu of this being fixed in acpica, introduce acpi_pptt_cache_v1_full to
> contain all the fields of the Cache Type Structure . Update the existing
> code to use this new struct. This simplifies the code and removes a
> non-standard use of ACPI_ADD_PTR.
To me, reading the code its a lot clearer that there is a version
difference in the subtable this way.
Reviewed-by: Jeremy Linton <jeremy.linton@arm.com>
>
> Signed-off-by: Ben Horgan <ben.horgan@arm.com>
> ---
> I have opened a pull request to acpica to update acpi_pptt_cache_v1 to
> include all fields. https://github.com/acpica/acpica/pull/1059
>
> Change since v4:
> Use fields directly in acpi_pptt_cache_v1_full
> Delay the casting
>
> Changes since v3:
> New patch
> ---
> drivers/acpi/pptt.c | 47 +++++++++++++++++++++++++++++++++++----------
> 1 file changed, 37 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c
> index 2856254e29d7..53fde9bd8140 100644
> --- a/drivers/acpi/pptt.c
> +++ b/drivers/acpi/pptt.c
> @@ -21,6 +21,25 @@
> #include <linux/cacheinfo.h>
> #include <acpi/processor.h>
>
> +/*
> + * The acpi_pptt_cache_v1 in actbl2.h, which is imported from acpica,
> + * only contains the cache_id field rather than all the fields of the
> + * Cache Type Structure. Use this alternative structure until it is
> + * resolved in acpica.
> + */
> +struct acpi_pptt_cache_v1_full {
> + struct acpi_subtable_header header;
> + u16 reserved;
> + u32 flags;
> + u32 next_level_of_cache;
> + u32 size;
> + u32 number_of_sets;
> + u8 associativity;
> + u8 attributes;
> + u16 line_size;
> + u32 cache_id;
> +};
> +
> static struct acpi_subtable_header *fetch_pptt_subtable(struct acpi_table_header *table_hdr,
> u32 pptt_ref)
> {
> @@ -56,6 +75,18 @@ static struct acpi_pptt_cache *fetch_pptt_cache(struct acpi_table_header *table_
> return (struct acpi_pptt_cache *)fetch_pptt_subtable(table_hdr, pptt_ref);
> }
>
> +static struct acpi_pptt_cache_v1_full *upgrade_pptt_cache(struct acpi_pptt_cache *cache)
> +{
> + if (cache->header.length < sizeof(struct acpi_pptt_cache_v1_full))
> + return NULL;
> +
> + /* No use for v1 if the only additional field is invalid */
> + if (!(cache->flags & ACPI_PPTT_CACHE_ID_VALID))
> + return NULL;
> +
> + return (struct acpi_pptt_cache_v1_full *)cache;
> +}
> +
> static struct acpi_subtable_header *acpi_get_pptt_resource(struct acpi_table_header *table_hdr,
> struct acpi_pptt_processor *node,
> int resource)
> @@ -111,7 +142,7 @@ static unsigned int acpi_pptt_walk_cache(struct acpi_table_header *table_hdr,
> if (res->type != ACPI_PPTT_TYPE_CACHE)
> return 0;
>
> - cache = (struct acpi_pptt_cache *) res;
> + cache = (struct acpi_pptt_cache *)res;
> while (cache) {
> local_level++;
>
> @@ -355,7 +386,6 @@ static struct acpi_pptt_cache *acpi_find_cache_node(struct acpi_table_header *ta
> * @this_leaf: Kernel cache info structure being updated
> * @found_cache: The PPTT node describing this cache instance
> * @cpu_node: A unique reference to describe this cache instance
> - * @revision: The revision of the PPTT table
> *
> * The ACPI spec implies that the fields in the cache structures are used to
> * extend and correct the information probed from the hardware. Lets only
> @@ -365,10 +395,9 @@ static struct acpi_pptt_cache *acpi_find_cache_node(struct acpi_table_header *ta
> */
> static void update_cache_properties(struct cacheinfo *this_leaf,
> struct acpi_pptt_cache *found_cache,
> - struct acpi_pptt_processor *cpu_node,
> - u8 revision)
> + struct acpi_pptt_processor *cpu_node)
> {
> - struct acpi_pptt_cache_v1* found_cache_v1;
> + struct acpi_pptt_cache_v1_full *found_cache_v1;
>
> this_leaf->fw_token = cpu_node;
> if (found_cache->flags & ACPI_PPTT_SIZE_PROPERTY_VALID)
> @@ -418,9 +447,8 @@ static void update_cache_properties(struct cacheinfo *this_leaf,
> found_cache->flags & ACPI_PPTT_CACHE_TYPE_VALID)
> this_leaf->type = CACHE_TYPE_UNIFIED;
>
> - if (revision >= 3 && (found_cache->flags & ACPI_PPTT_CACHE_ID_VALID)) {
> - found_cache_v1 = ACPI_ADD_PTR(struct acpi_pptt_cache_v1,
> - found_cache, sizeof(struct acpi_pptt_cache));
> + found_cache_v1 = upgrade_pptt_cache(found_cache);
> + if (found_cache_v1) {
> this_leaf->id = found_cache_v1->cache_id;
> this_leaf->attributes |= CACHE_ID;
> }
> @@ -445,8 +473,7 @@ static void cache_setup_acpi_cpu(struct acpi_table_header *table,
> pr_debug("found = %p %p\n", found_cache, cpu_node);
> if (found_cache)
> update_cache_properties(this_leaf, found_cache,
> - ACPI_TO_POINTER(ACPI_PTR_DIFF(cpu_node, table)),
> - table->revision);
> + ACPI_TO_POINTER(ACPI_PTR_DIFF(cpu_node, table)));
>
> index++;
> }
On 2025/11/18 0:59, Ben Horgan wrote:
> In actbl2.h, acpi_pptt_cache describes the fields in the original
> Cache Type Structure. In PPTT table version 3 a new field was added at the
> end, cache_id. This is described in acpi_pptt_cache_v1 but rather than
> including all v1 fields it just includes this one.
>
> In lieu of this being fixed in acpica, introduce acpi_pptt_cache_v1_full to
> contain all the fields of the Cache Type Structure . Update the existing
> code to use this new struct. This simplifies the code and removes a
> non-standard use of ACPI_ADD_PTR.
>
> Signed-off-by: Ben Horgan <ben.horgan@arm.com>
> ---
> I have opened a pull request to acpica to update acpi_pptt_cache_v1 to
> include all fields. https://github.com/acpica/acpica/pull/1059
>
> Change since v4:
> Use fields directly in acpi_pptt_cache_v1_full
> Delay the casting
>
> Changes since v3:
> New patch
> ---
> drivers/acpi/pptt.c | 47 +++++++++++++++++++++++++++++++++++----------
> 1 file changed, 37 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c
> index 2856254e29d7..53fde9bd8140 100644
> --- a/drivers/acpi/pptt.c
> +++ b/drivers/acpi/pptt.c
> @@ -21,6 +21,25 @@
> #include <linux/cacheinfo.h>
> #include <acpi/processor.h>
>
> +/*
> + * The acpi_pptt_cache_v1 in actbl2.h, which is imported from acpica,
> + * only contains the cache_id field rather than all the fields of the
> + * Cache Type Structure. Use this alternative structure until it is
> + * resolved in acpica.
> + */
> +struct acpi_pptt_cache_v1_full {
> + struct acpi_subtable_header header;
> + u16 reserved;
> + u32 flags;
> + u32 next_level_of_cache;
> + u32 size;
> + u32 number_of_sets;
> + u8 associativity;
> + u8 attributes;
> + u16 line_size;
> + u32 cache_id;
> +};
I'm fine with removing this after acpica changes being accepted.
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Thanks
Hanjun
On 11/18/25 2:59 AM, Ben Horgan wrote: > In actbl2.h, acpi_pptt_cache describes the fields in the original > Cache Type Structure. In PPTT table version 3 a new field was added at the > end, cache_id. This is described in acpi_pptt_cache_v1 but rather than > including all v1 fields it just includes this one. > > In lieu of this being fixed in acpica, introduce acpi_pptt_cache_v1_full to > contain all the fields of the Cache Type Structure . Update the existing > code to use this new struct. This simplifies the code and removes a > non-standard use of ACPI_ADD_PTR. > > Signed-off-by: Ben Horgan <ben.horgan@arm.com> > --- > I have opened a pull request to acpica to update acpi_pptt_cache_v1 to > include all fields. https://github.com/acpica/acpica/pull/1059 > > Change since v4: > Use fields directly in acpi_pptt_cache_v1_full > Delay the casting > > Changes since v3: > New patch > --- > drivers/acpi/pptt.c | 47 +++++++++++++++++++++++++++++++++++---------- > 1 file changed, 37 insertions(+), 10 deletions(-) > With '__packed' added as pointed by Fenghua, LKTM. Reviewed-by: Gavin Shan <gshan@redhat.com>
On Mon, 17 Nov 2025 16:59:42 +0000
Ben Horgan <ben.horgan@arm.com> wrote:
> In actbl2.h, acpi_pptt_cache describes the fields in the original
> Cache Type Structure. In PPTT table version 3 a new field was added at the
> end, cache_id. This is described in acpi_pptt_cache_v1 but rather than
> including all v1 fields it just includes this one.
>
> In lieu of this being fixed in acpica, introduce acpi_pptt_cache_v1_full to
> contain all the fields of the Cache Type Structure . Update the existing
> code to use this new struct. This simplifies the code and removes a
> non-standard use of ACPI_ADD_PTR.
>
> Signed-off-by: Ben Horgan <ben.horgan@arm.com>
Hi Ben,
I'd like the change to land in ACPICA but if it doesn't this might need
a future rework to avoid long term duplication. For now with the __packed
marking and a few formatting niggles (see inline) tidied up.
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
> ---
> I have opened a pull request to acpica to update acpi_pptt_cache_v1 to
> include all fields. https://github.com/acpica/acpica/pull/1059
>
> Change since v4:
> Use fields directly in acpi_pptt_cache_v1_full
> Delay the casting
>
> Changes since v3:
> New patch
> ---
> drivers/acpi/pptt.c | 47 +++++++++++++++++++++++++++++++++++----------
> 1 file changed, 37 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c
> index 2856254e29d7..53fde9bd8140 100644
> --- a/drivers/acpi/pptt.c
> +++ b/drivers/acpi/pptt.c
> @@ -21,6 +21,25 @@
> #include <linux/cacheinfo.h>
> #include <acpi/processor.h>
>
> +/*
> + * The acpi_pptt_cache_v1 in actbl2.h, which is imported from acpica,
> + * only contains the cache_id field rather than all the fields of the
> + * Cache Type Structure. Use this alternative structure until it is
> + * resolved in acpica.
> + */
> +struct acpi_pptt_cache_v1_full {
> + struct acpi_subtable_header header;
> + u16 reserved;
> + u32 flags;
> + u32 next_level_of_cache;
> + u32 size;
> + u32 number_of_sets;
> + u8 associativity;
> + u8 attributes;
> + u16 line_size;
> + u32 cache_id;
> +};
> +
> static struct acpi_subtable_header *fetch_pptt_subtable(struct acpi_table_header *table_hdr,
> u32 pptt_ref)
> {
> @@ -56,6 +75,18 @@ static struct acpi_pptt_cache *fetch_pptt_cache(struct acpi_table_header *table_
> return (struct acpi_pptt_cache *)fetch_pptt_subtable(table_hdr, pptt_ref);
> }
>
> +static struct acpi_pptt_cache_v1_full *upgrade_pptt_cache(struct acpi_pptt_cache *cache)
> +{
> + if (cache->header.length < sizeof(struct acpi_pptt_cache_v1_full))
> + return NULL;
> +
> + /* No use for v1 if the only additional field is invalid */
> + if (!(cache->flags & ACPI_PPTT_CACHE_ID_VALID))
> + return NULL;
> +
> + return (struct acpi_pptt_cache_v1_full *)cache;
> +}
> +
> static struct acpi_subtable_header *acpi_get_pptt_resource(struct acpi_table_header *table_hdr,
> struct acpi_pptt_processor *node,
> int resource)
> @@ -111,7 +142,7 @@ static unsigned int acpi_pptt_walk_cache(struct acpi_table_header *table_hdr,
> if (res->type != ACPI_PPTT_TYPE_CACHE)
> return 0;
>
> - cache = (struct acpi_pptt_cache *) res;
> + cache = (struct acpi_pptt_cache *)res;
Unrelated change..
> while (cache) {
> local_level++;
>
> @@ -355,7 +386,6 @@ static struct acpi_pptt_cache *acpi_find_cache_node(struct acpi_table_header *ta
> * @this_leaf: Kernel cache info structure being updated
> * @found_cache: The PPTT node describing this cache instance
> * @cpu_node: A unique reference to describe this cache instance
> - * @revision: The revision of the PPTT table
> *
> * The ACPI spec implies that the fields in the cache structures are used to
> * extend and correct the information probed from the hardware. Lets only
> @@ -365,10 +395,9 @@ static struct acpi_pptt_cache *acpi_find_cache_node(struct acpi_table_header *ta
> */
> static void update_cache_properties(struct cacheinfo *this_leaf,
> struct acpi_pptt_cache *found_cache,
> - struct acpi_pptt_processor *cpu_node,
> - u8 revision)
> + struct acpi_pptt_processor *cpu_node)
> {
> - struct acpi_pptt_cache_v1* found_cache_v1;
> + struct acpi_pptt_cache_v1_full *found_cache_v1;
>
> this_leaf->fw_token = cpu_node;
> if (found_cache->flags & ACPI_PPTT_SIZE_PROPERTY_VALID)
> @@ -418,9 +447,8 @@ static void update_cache_properties(struct cacheinfo *this_leaf,
> found_cache->flags & ACPI_PPTT_CACHE_TYPE_VALID)
> this_leaf->type = CACHE_TYPE_UNIFIED;
>
> - if (revision >= 3 && (found_cache->flags & ACPI_PPTT_CACHE_ID_VALID)) {
> - found_cache_v1 = ACPI_ADD_PTR(struct acpi_pptt_cache_v1,
> - found_cache, sizeof(struct acpi_pptt_cache));
> + found_cache_v1 = upgrade_pptt_cache(found_cache);
extra space after =
> + if (found_cache_v1) {
> this_leaf->id = found_cache_v1->cache_id;
> this_leaf->attributes |= CACHE_ID;
> }
> @@ -445,8 +473,7 @@ static void cache_setup_acpi_cpu(struct acpi_table_header *table,
> pr_debug("found = %p %p\n", found_cache, cpu_node);
> if (found_cache)
> update_cache_properties(this_leaf, found_cache,
> - ACPI_TO_POINTER(ACPI_PTR_DIFF(cpu_node, table)),
> - table->revision);
> + ACPI_TO_POINTER(ACPI_PTR_DIFF(cpu_node, table)));
>
> index++;
> }
Hi, Ben,
On 11/17/25 08:59, Ben Horgan wrote:
> In actbl2.h, acpi_pptt_cache describes the fields in the original
> Cache Type Structure. In PPTT table version 3 a new field was added at the
> end, cache_id. This is described in acpi_pptt_cache_v1 but rather than
> including all v1 fields it just includes this one.
>
> In lieu of this being fixed in acpica, introduce acpi_pptt_cache_v1_full to
> contain all the fields of the Cache Type Structure . Update the existing
> code to use this new struct. This simplifies the code and removes a
> non-standard use of ACPI_ADD_PTR.
>
> Signed-off-by: Ben Horgan <ben.horgan@arm.com>
> ---
> I have opened a pull request to acpica to update acpi_pptt_cache_v1 to
> include all fields. https://github.com/acpica/acpica/pull/1059
>
> Change since v4:
> Use fields directly in acpi_pptt_cache_v1_full
> Delay the casting
>
> Changes since v3:
> New patch
> ---
> drivers/acpi/pptt.c | 47 +++++++++++++++++++++++++++++++++++----------
> 1 file changed, 37 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c
> index 2856254e29d7..53fde9bd8140 100644
> --- a/drivers/acpi/pptt.c
> +++ b/drivers/acpi/pptt.c
> @@ -21,6 +21,25 @@
> #include <linux/cacheinfo.h>
> #include <acpi/processor.h>
>
> +/*
> + * The acpi_pptt_cache_v1 in actbl2.h, which is imported from acpica,
> + * only contains the cache_id field rather than all the fields of the
> + * Cache Type Structure. Use this alternative structure until it is
> + * resolved in acpica.
> + */
> +struct acpi_pptt_cache_v1_full {
> + struct acpi_subtable_header header;
> + u16 reserved;
> + u32 flags;
> + u32 next_level_of_cache;
> + u32 size;
> + u32 number_of_sets;
> + u8 associativity;
> + u8 attributes;
> + u16 line_size;
> + u32 cache_id;
> +};
Should "__packed" be added to this table?
Should this table be defined in include/acpi/actbl2.h? Seems defining
the two cache tables separately in two places are not natural?
Thanks.
-Fenghua
Hi Fenghua,
On 11/18/25 04:03, Fenghua Yu wrote:
> Hi, Ben,
>
> On 11/17/25 08:59, Ben Horgan wrote:
>> In actbl2.h, acpi_pptt_cache describes the fields in the original
>> Cache Type Structure. In PPTT table version 3 a new field was added at
>> the
>> end, cache_id. This is described in acpi_pptt_cache_v1 but rather than
>> including all v1 fields it just includes this one.
>>
>> In lieu of this being fixed in acpica, introduce
>> acpi_pptt_cache_v1_full to
>> contain all the fields of the Cache Type Structure . Update the existing
>> code to use this new struct. This simplifies the code and removes a
>> non-standard use of ACPI_ADD_PTR.
>>
>> Signed-off-by: Ben Horgan <ben.horgan@arm.com>
>> ---
>> I have opened a pull request to acpica to update acpi_pptt_cache_v1 to
>> include all fields. https://github.com/acpica/acpica/pull/1059
>>
>> Change since v4:
>> Use fields directly in acpi_pptt_cache_v1_full
>> Delay the casting
>>
>> Changes since v3:
>> New patch
>> ---
>> drivers/acpi/pptt.c | 47 +++++++++++++++++++++++++++++++++++----------
>> 1 file changed, 37 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c
>> index 2856254e29d7..53fde9bd8140 100644
>> --- a/drivers/acpi/pptt.c
>> +++ b/drivers/acpi/pptt.c
>> @@ -21,6 +21,25 @@
>> #include <linux/cacheinfo.h>
>> #include <acpi/processor.h>
>> +/*
>> + * The acpi_pptt_cache_v1 in actbl2.h, which is imported from acpica,
>> + * only contains the cache_id field rather than all the fields of the
>> + * Cache Type Structure. Use this alternative structure until it is
>> + * resolved in acpica.
>> + */
>> +struct acpi_pptt_cache_v1_full {
>> + struct acpi_subtable_header header;
>> + u16 reserved;
>> + u32 flags;
>> + u32 next_level_of_cache;
>> + u32 size;
>> + u32 number_of_sets;
>> + u8 associativity;
>> + u8 attributes;
>> + u16 line_size;
>> + u32 cache_id;
>> +};
>
> Should "__packed" be added to this table?
Yes, I missed that.
>
> Should this table be defined in include/acpi/actbl2.h? Seems defining
> the two cache tables separately in two places are not natural?
Indeed. The dificulty is that include/acpi/actbl2.h is generated from
acpica. I propose a fix for this in the pull request mentioned above:
https://github.com/acpica/acpica/pull/1059 This extends
acpi_pptt_cache_v1 to include all the fields in the new version of the
cache type structure (not just cache_id).
One thing I could do if it looks like the acpica change will be accepted
is to temporarily delete acpi_pptt_cache_v1 from include/acpi/actbl2.h
and rename acpi_pptt_cache_v1_full in drivers/acpi/pptt.c to
acpi_pptt_cache_v1. When include/acpi/actbl2.h is updated the conflict
should be evident and the version in drivers/acpi/pptt.c can be dropped.
I'll keep it like it is for now though as this would be an api breaking
change for acpica and the maintainers may prefer to handle this a
different way.
>
> Thanks.
>
> -Fenghua
Thanks,
Ben
On 11/18/25 02:57, Ben Horgan wrote:
> Hi Fenghua,
>
> On 11/18/25 04:03, Fenghua Yu wrote:
>> Hi, Ben,
>>
>> On 11/17/25 08:59, Ben Horgan wrote:
>>> In actbl2.h, acpi_pptt_cache describes the fields in the original
>>> Cache Type Structure. In PPTT table version 3 a new field was added at
>>> the
>>> end, cache_id. This is described in acpi_pptt_cache_v1 but rather than
>>> including all v1 fields it just includes this one.
>>>
>>> In lieu of this being fixed in acpica, introduce
>>> acpi_pptt_cache_v1_full to
>>> contain all the fields of the Cache Type Structure . Update the existing
>>> code to use this new struct. This simplifies the code and removes a
>>> non-standard use of ACPI_ADD_PTR.
>>>
>>> Signed-off-by: Ben Horgan <ben.horgan@arm.com>
>>> ---
>>> I have opened a pull request to acpica to update acpi_pptt_cache_v1 to
>>> include all fields. https://github.com/acpica/acpica/pull/1059
>>>
>>> Change since v4:
>>> Use fields directly in acpi_pptt_cache_v1_full
>>> Delay the casting
>>>
>>> Changes since v3:
>>> New patch
>>> ---
>>> drivers/acpi/pptt.c | 47 +++++++++++++++++++++++++++++++++++----------
>>> 1 file changed, 37 insertions(+), 10 deletions(-)
>>>
>>> diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c
>>> index 2856254e29d7..53fde9bd8140 100644
>>> --- a/drivers/acpi/pptt.c
>>> +++ b/drivers/acpi/pptt.c
>>> @@ -21,6 +21,25 @@
>>> #include <linux/cacheinfo.h>
>>> #include <acpi/processor.h>
>>> +/*
>>> + * The acpi_pptt_cache_v1 in actbl2.h, which is imported from acpica,
>>> + * only contains the cache_id field rather than all the fields of the
>>> + * Cache Type Structure. Use this alternative structure until it is
>>> + * resolved in acpica.
>>> + */
>>> +struct acpi_pptt_cache_v1_full {
>>> + struct acpi_subtable_header header;
>>> + u16 reserved;
>>> + u32 flags;
>>> + u32 next_level_of_cache;
>>> + u32 size;
>>> + u32 number_of_sets;
>>> + u8 associativity;
>>> + u8 attributes;
>>> + u16 line_size;
>>> + u32 cache_id;
>>> +};
>>
>> Should "__packed" be added to this table?
>
> Yes, I missed that.
>
With this fixed,
Reviewed-by: Fenghua Yu <fenghuay@nvidia.com>
>>
>> Should this table be defined in include/acpi/actbl2.h? Seems defining
>> the two cache tables separately in two places are not natural?
>
> Indeed. The dificulty is that include/acpi/actbl2.h is generated from
> acpica. I propose a fix for this in the pull request mentioned above:
> https://github.com/acpica/acpica/pull/1059 This extends
> acpi_pptt_cache_v1 to include all the fields in the new version of the
> cache type structure (not just cache_id).
>
> One thing I could do if it looks like the acpica change will be accepted
> is to temporarily delete acpi_pptt_cache_v1 from include/acpi/actbl2.h
> and rename acpi_pptt_cache_v1_full in drivers/acpi/pptt.c to
> acpi_pptt_cache_v1. When include/acpi/actbl2.h is updated the conflict
> should be evident and the version in drivers/acpi/pptt.c can be dropped.
> I'll keep it like it is for now though as this would be an api breaking
> change for acpica and the maintainers may prefer to handle this a
> different way.
Right. Thank you for your explanation!
-Fenghua
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