linux-kernel - [PATCH v2 1/3] cacheinfo: Check sib_leaf in cache_leaves_are

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Message-Id: <20230412071809.12670-2-pierre.gondois@arm.com>
Date:   Wed, 12 Apr 2023 09:18:04 +0200
From:   Pierre Gondois <pierre.gondois@....com>
To:     linux-kernel@...r.kernel.org
Cc:     Radu Rendec <rrendec@...hat.com>,
        Alexandre Ghiti <alexghiti@...osinc.com>,
        Conor Dooley <conor.dooley@...rochip.com>,
        Will Deacon <will@...nel.org>,
        Pierre Gondois <pierre.gondois@....com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Sudeep Holla <sudeep.holla@....com>,
        Palmer Dabbelt <palmer@...osinc.com>,
        Gavin Shan <gshan@...hat.com>,
        Jeremy Linton <jeremy.linton@....com>
Subject: [PATCH v2 1/3] cacheinfo: Check sib_leaf in cache_leaves_are_shared()

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.

Check 'sib_leaf->level'. Also update the comment as the function is
called when populating 'shared_cpu_map'.

Fixes: f16d1becf96f ("cacheinfo: Use cache identifiers to check if the caches are shared if available")
Signed-off-by: Pierre Gondois <pierre.gondois@....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 f3903d002819..e7ad6aba5f97 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);
 
 	if ((sib_leaf->attributes & CACHE_ID) &&
 	    (this_leaf->attributes & CACHE_ID))
-- 
2.25.1