On 14/09/18 17:28, 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 <vkil...@codeaurora.org>
> Signed-off-by: Jeffrey Hugo <jh...@codeaurora.org>
> ---
> drivers/acpi/pptt.c | 15 +++++++++++----
> 1 file changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c
> index d1e26cb..bb00ed9 100644
> --- a/drivers/acpi/pptt.c
> +++ b/drivers/acpi/pptt.c
> @@ -402,11 +402,18 @@ 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 either the cache has
> + * been fully specified in PPTT, or 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)
> + 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;
I thought I did mention that we can drop the valid_flags altogether
unless Jeremy has reasons not to.
--
Regards,
Sudeep
