cacheinfo: Use cache identifiers to check if the caches are shared if available

The cache identifiers is an optional property on most of the platforms.
The presence of one must be indicated by the CACHE_ID valid bit in the
attributes.

We can use the cache identifiers provided by the firmware to check if
any two cpus share the same cache instead of relying on the fw_token
generated and set in the OS.

Link: https://lore.kernel.org/r/20220704101605.1318280-8-sudeep.holla@arm.com
Tested-by: Ionela Voinescu <ionela.voinescu@arm.com>
Tested-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c
index 4d21a1022fa9214da0023f897dde8b4aff32097d..e331b399adeb7eb5049e9712c3d894f0b6d95535 100644 (file)
--- a/drivers/base/cacheinfo.c
+++ b/drivers/base/cacheinfo.c
@@ -44,6 +44,10 @@ static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
        if (!(IS_ENABLED(CONFIG_OF) || IS_ENABLED(CONFIG_ACPI)))
                return !(this_leaf->level == 1);
 
+       if ((sib_leaf->attributes & CACHE_ID) &&
+           (this_leaf->attributes & CACHE_ID))
+               return sib_leaf->id == this_leaf->id;
+
        return sib_leaf->fw_token == this_leaf->fw_token;
 }
 
@@ -56,7 +60,8 @@ bool last_level_cache_is_valid(unsigned int cpu)
 
        llc = per_cpu_cacheinfo_idx(cpu, cache_leaves(cpu) - 1);
 
-       return !!llc->fw_token;
+       return (llc->attributes & CACHE_ID) || !!llc->fw_token;
+
 }
 
 bool last_level_cache_is_shared(unsigned int cpu_x, unsigned int cpu_y)