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

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Date:   Mon, 27 Mar 2023 13:59:49 +0200
From:   Pierre Gondois <pierre.gondois@....com>
To:     linux-kernel@...r.kernel.org
Cc:     Radu Rendec <rrendec@...hat.com>,
        Pierre Gondois <pierre.gondois@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Sudeep Holla <sudeep.holla@....com>,
        Oliver Upton <oliver.upton@...ux.dev>,
        Akihiko Odaki <akihiko.odaki@...nix.com>,
        Palmer Dabbelt <palmer@...osinc.com>,
        Gavin Shan <gshan@...hat.com>,
        linux-arm-kernel@...ts.infradead.org
Subject: [PATCH 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.

Also update the comment: the function is called when populating
'shared_cpu_map'.

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