1 files changed, 53 insertions, 22 deletions

diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c
index f6573c335f4c..6e0a44bad305 100644
--- a/drivers/base/cacheinfo.c
+++ b/drivers/base/cacheinfo.c
@@ -398,6 +398,11 @@ static void free_cache_attributes(unsigned int cpu)
 	cache_shared_cpu_map_remove(cpu);
 }
 
+int __weak early_cache_level(unsigned int cpu)
+{
+	return -ENOENT;
+}
+
 int __weak init_cache_level(unsigned int cpu)
 {
 	return -ENOENT;
@@ -423,56 +428,82 @@ int allocate_cache_info(int cpu)
 
 int fetch_cache_info(unsigned int cpu)
 {
-	struct cpu_cacheinfo *this_cpu_ci;
+	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 	unsigned int levels = 0, split_levels = 0;
 	int ret;
 
 	if (acpi_disabled) {
 		ret = init_of_cache_level(cpu);
-		if (ret < 0)
-			return ret;
 	} else {
 		ret = acpi_get_cache_info(cpu, &levels, &split_levels);
-		if (ret < 0)
+		if (!ret) {
+			this_cpu_ci->num_levels = levels;
+			/*
+			 * This assumes that:
+			 * - there cannot be any split caches (data/instruction)
+			 *   above a unified cache
+			 * - data/instruction caches come by pair
+			 */
+			this_cpu_ci->num_leaves = levels + split_levels;
+		}
+	}
+
+	if (ret || !cache_leaves(cpu)) {
+		ret = early_cache_level(cpu);
+		if (ret)
 			return ret;
 
-		this_cpu_ci = get_cpu_cacheinfo(cpu);
-		this_cpu_ci->num_levels = levels;
-		/*
-		 * This assumes that:
-		 * - there cannot be any split caches (data/instruction)
-		 *   above a unified cache
-		 * - data/instruction caches come by pair
-		 */
-		this_cpu_ci->num_leaves = levels + split_levels;
+		if (!cache_leaves(cpu))
+			return -ENOENT;
+
+		this_cpu_ci->early_ci_levels = true;
 	}
-	if (!cache_leaves(cpu))
-		return -ENOENT;
 
 	return allocate_cache_info(cpu);
 }
 
-int detect_cache_attributes(unsigned int cpu)
+static inline int init_level_allocate_ci(unsigned int cpu)
 {
-	int ret;
+	unsigned int early_leaves = cache_leaves(cpu);
 
 	/* Since early initialization/allocation of the cacheinfo is allowed
 	 * via fetch_cache_info() and this also gets called as CPU hotplug
 	 * callbacks via cacheinfo_cpu_online, the init/alloc can be skipped
 	 * as it will happen only once (the cacheinfo memory is never freed).
-	 * Just populate the cacheinfo.
+	 * Just populate the cacheinfo. However, if the cacheinfo has been
+	 * allocated early through the arch-specific early_cache_level() call,
+	 * there is a chance the info is wrong (this can happen on arm64). In
+	 * that case, call init_cache_level() anyway to give the arch-specific
+	 * code a chance to make things right.
 	 */
-	if (per_cpu_cacheinfo(cpu))
-		goto populate_leaves;
+	if (per_cpu_cacheinfo(cpu) && !ci_cacheinfo(cpu)->early_ci_levels)
+		return 0;
 
 	if (init_cache_level(cpu) || !cache_leaves(cpu))
 		return -ENOENT;
 
-	ret = allocate_cache_info(cpu);
+	/*
+	 * Now that we have properly initialized the cache level info, make
+	 * sure we don't try to do that again the next time we are called
+	 * (e.g. as CPU hotplug callbacks).
+	 */
+	ci_cacheinfo(cpu)->early_ci_levels = false;
+
+	if (cache_leaves(cpu) <= early_leaves)
+		return 0;
+
+	kfree(per_cpu_cacheinfo(cpu));
+	return allocate_cache_info(cpu);
+}
+
+int detect_cache_attributes(unsigned int cpu)
+{
+	int ret;
+
+	ret = init_level_allocate_ci(cpu);
 	if (ret)
 		return ret;
 
-populate_leaves:
 	/*
 	 * populate_cache_leaves() may completely setup the cache leaves and
 	 * shared_cpu_map or it may leave it partially setup.