Patch "cacheinfo: Check cache properties are present in DT" has been added to the 6.3-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    cacheinfo: Check cache properties are present in DT

to the 6.3-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     cacheinfo-check-cache-properties-are-present-in-dt.patch
and it can be found in the queue-6.3 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 3b68d41f76a17585b4232d0a55d212fa0fd99d91
Author: Pierre Gondois <pierre.gondois@xxxxxxx>
Date:   Fri Apr 14 10:14:50 2023 +0200

    cacheinfo: Check cache properties are present in DT
    
    [ Upstream commit cde0fbff07eff7e4e0e85fa053fe19a24c86b1e0 ]
    
    If a Device Tree (DT) is used, the presence of cache properties is
    assumed. Not finding any is not considered. For arm64 platforms,
    cache information can be fetched from the clidr_el1 register.
    Checking whether cache information is available in the DT
    allows to switch to using clidr_el1.
    
    init_of_cache_level()
    \-of_count_cache_leaves()
    will assume there a 2 cache leaves (L1 data/instruction caches), which
    can be different from clidr_el1 information.
    
    cache_setup_of_node() tries to read cache properties in the DT.
    If there are none, this is considered a success. Knowing no
    information was available would allow to switch to using clidr_el1.
    
    Fixes: de0df442ee49 ("cacheinfo: Check 'cache-unified' property to count cache leaves")
    Reported-by: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>
    Link: https://lore.kernel.org/all/20230404-hatred-swimmer-6fecdf33b57a@spud/
    Signed-off-by: Pierre Gondois <pierre.gondois@xxxxxxx>
    Reviewed-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
    Link: https://lore.kernel.org/r/20230414081453.244787-3-pierre.gondois@xxxxxxx
    Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c
index c5d2293ac2a63..ea8f416852bd9 100644
--- a/drivers/base/cacheinfo.c
+++ b/drivers/base/cacheinfo.c
@@ -78,6 +78,9 @@ bool last_level_cache_is_shared(unsigned int cpu_x, unsigned int cpu_y)
 }
 
 #ifdef CONFIG_OF
+
+static bool of_check_cache_nodes(struct device_node *np);
+
 /* OF properties to query for a given cache type */
 struct cache_type_info {
 	const char *size_prop;
@@ -205,6 +208,11 @@ static int cache_setup_of_node(unsigned int cpu)
 		return -ENOENT;
 	}
 
+	if (!of_check_cache_nodes(np)) {
+		of_node_put(np);
+		return -ENOENT;
+	}
+
 	prev = np;
 
 	while (index < cache_leaves(cpu)) {
@@ -229,6 +237,25 @@ static int cache_setup_of_node(unsigned int cpu)
 	return 0;
 }
 
+static bool of_check_cache_nodes(struct device_node *np)
+{
+	struct device_node *next;
+
+	if (of_property_present(np, "cache-size")   ||
+	    of_property_present(np, "i-cache-size") ||
+	    of_property_present(np, "d-cache-size") ||
+	    of_property_present(np, "cache-unified"))
+		return true;
+
+	next = of_find_next_cache_node(np);
+	if (next) {
+		of_node_put(next);
+		return true;
+	}
+
+	return false;
+}
+
 static int of_count_cache_leaves(struct device_node *np)
 {
 	unsigned int leaves = 0;
@@ -260,6 +287,11 @@ int init_of_cache_level(unsigned int cpu)
 	struct device_node *prev = NULL;
 	unsigned int levels = 0, leaves, level;
 
+	if (!of_check_cache_nodes(np)) {
+		of_node_put(np);
+		return -ENOENT;
+	}
+
 	leaves = of_count_cache_leaves(np);
 	if (leaves > 0)
 		levels = 1;