Re: [PATCH 1/3] cacheinfo: Check sib_leaf in cache_leaves_are_shared()

Conor Dooley
2023-03-27T13:54:36Z

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On Mon, Mar 27, 2023 at 01:59:49PM +0200, Pierre Gondois wrote:
> If 'this_leaf' is a L2 cache (or higher) and 'sib_leaf' is a L1 cache,
> the caches are detected as shared.
> Indeed, cache_leaves_are_shared() only checks the cache level of
> 'this_leaf' when 'sib_leaf''s cache level should also be checked.

nit: this commit message reads quite weirdly as there's a missing "do
foo" statement, followed by "also do bar".

>
> Also update the comment: the function is called when populating
> 'shared_cpu_map'.
>
> Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
> ---
> drivers/base/cacheinfo.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c
> index f6573c335f4c..4ca117574af1 100644
> --- a/drivers/base/cacheinfo.c
> +++ b/drivers/base/cacheinfo.c
> @@ -38,11 +38,10 @@ static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
> {
> /*
> * For non DT/ACPI systems, assume unique level 1 caches,
> - * system-wide shared caches for all other levels. This will be used
> - * only if arch specific code has not populated shared_cpu_map
> + * system-wide shared caches for all other levels.
> */
> if (!(IS_ENABLED(CONFIG_OF) || IS_ENABLED(CONFIG_ACPI)))
> - return !(this_leaf->level == 1);
> + return (this_leaf->level != 1) || (sib_leaf->level != 1);

So this is
Fixes: f16d1becf96f ("cacheinfo: Use cache identifiers to check if the caches are shared if available")
then?

Cheers,
Conor.

>
> if ((sib_leaf->attributes & CACHE_ID) &&
> (this_leaf->attributes & CACHE_ID))
> --
> 2.25.1
>
>

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