[PATCH RFC 06/15] arm_mpam: Fix cache ID sentinel from ~0UL to U32_MAX to match u32 return type

[Yin Li]

cache_of_calculate_id() returns u32, but callers stored the result in
unsigned long variables and compared against ~0UL. On 64-bit systems,
U32_MAX (0xffffffff) assigned to unsigned long becomes 0x00000000ffffffff,
which does not equal ~0UL (0xffffffffffffffff), so invalid cache IDs are
silently accepted instead of being rejected.

Fix by changing all cache ID and component ID variables that receive the
return value of cache_of_calculate_id() to u32, and replace all ~0 and
~0UL sentinel comparisons with U32_MAX.

Also fix the sentinel values in cache_of_calculate_id() itself for
consistency.

Signed-off-by: Yin Li <yin.li@xxxxxxxxxxxxxxxx>
---
 drivers/base/cacheinfo.c        |  6 +++---
 drivers/resctrl/mpam_devices.c  | 16 ++++++++--------
 drivers/resctrl/mpam_internal.h |  2 +-
 3 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c
index f75e7f64038b..a4e0d1d47e71 100644
--- a/drivers/base/cacheinfo.c
+++ b/drivers/base/cacheinfo.c
@@ -229,7 +229,7 @@ static bool match_cache_node(struct device_node *cpu,
 u32 cache_of_calculate_id(struct device_node *cache_node)
 {
 	struct device_node *cpu;
-	u32 min_id = ~0;
+	u32 min_id = U32_MAX;
 
 	for_each_of_cpu_node(cpu) {
 		u64 id = of_get_cpu_hwid(cpu, 0);
@@ -237,7 +237,7 @@ u32 cache_of_calculate_id(struct device_node *cache_node)
 		id = arch_compact_of_hwid(id);
 		if (FIELD_GET(GENMASK_ULL(63, 32), id)) {
 			of_node_put(cpu);
-			return ~0;
+			return U32_MAX;
 		}
 
 		if (match_cache_node(cpu, cache_node))
@@ -252,7 +252,7 @@ static void cache_of_set_id(struct cacheinfo *this_leaf,
 {
 	u32 id = cache_of_calculate_id(cache_node);
 
-	if (id != ~0) {
+	if (id != U32_MAX) {
 		this_leaf->id = id;
 		this_leaf->attributes |= CACHE_ID;
 	}
diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c
index 559fa09128b4..ddc15249ec1e 100644
--- a/drivers/resctrl/mpam_devices.c
+++ b/drivers/resctrl/mpam_devices.c
@@ -166,13 +166,13 @@ static void mpam_free_garbage(void)
 
 /* Called recursively to walk the list of caches from a particular CPU */
 static void __mpam_get_cpumask_from_cache_id(int cpu, struct device_node *cache_node,
-					     unsigned long cache_id,
+					     u32 cache_id,
 					     u32 cache_level,
 					     cpumask_t *affinity)
 {
 	int err;
 	u32 iter_level;
-	unsigned long iter_cache_id;
+	u32 iter_cache_id;
 	struct device_node *iter_node __free(device_node) = of_find_next_cache_node(cache_node);
 
 	if (!iter_node)
@@ -187,7 +187,7 @@ static void __mpam_get_cpumask_from_cache_id(int cpu, struct device_node *cache_
 	 * during device_initcall(). Use cache_of_calculate_id().
 	 */
 	iter_cache_id = cache_of_calculate_id(iter_node);
-	if (iter_cache_id == ~0UL)
+	if (iter_cache_id == U32_MAX)
 		return;
 
 	if (iter_level == cache_level && iter_cache_id == cache_id)
@@ -202,7 +202,7 @@ static void __mpam_get_cpumask_from_cache_id(int cpu, struct device_node *cache_
  * The cacheinfo structures are only populated when CPUs are online.
  * This helper walks the device tree to include offline CPUs too.
  */
-int mpam_get_cpumask_from_cache_id(unsigned long cache_id, u32 cache_level,
+int mpam_get_cpumask_from_cache_id(u32 cache_id, u32 cache_level,
 				   cpumask_t *affinity)
 {
 	int cpu;
@@ -229,7 +229,7 @@ static int get_cpumask_from_cache(struct device_node *cache,
 {
 	int err;
 	u32 cache_level;
-	unsigned long cache_id;
+	u32 cache_id;
 
 	err = of_property_read_u32(cache, "cache-level", &cache_level);
 	if (err) {
@@ -238,7 +238,7 @@ static int get_cpumask_from_cache(struct device_node *cache,
 	}
 
 	cache_id = cache_of_calculate_id(cache);
-	if (cache_id == ~0UL) {
+	if (cache_id == U32_MAX) {
 		pr_err("Failed to calculate cache-id from cache node\n");
 		return -ENOENT;
 	}
@@ -264,7 +264,7 @@ static int mpam_dt_parse_resource(struct mpam_msc *msc, struct device_node *np,
 {
 	int err = 0;
 	u32 class_id = 0;
-	unsigned long component_id = 0;
+	u32 component_id = 0;
 	struct device *dev = &msc->pdev->dev;
 	enum mpam_class_types type = MPAM_CLASS_UNKNOWN;
 	struct device_node *cache __free(device_node) = NULL;
@@ -308,7 +308,7 @@ static int mpam_dt_parse_resource(struct mpam_msc *msc, struct device_node *np,
 			return err;
 		}
 		component_id = cache_of_calculate_id(cache);
-		if (component_id == ~0) {
+		if (component_id == U32_MAX) {
 			dev_err_once(dev, "Failed to calculate cache-id\n");
 			return -ENOENT;
 		}
diff --git a/drivers/resctrl/mpam_internal.h b/drivers/resctrl/mpam_internal.h
index def0e3a65c23..aa45d00bcd07 100644
--- a/drivers/resctrl/mpam_internal.h
+++ b/drivers/resctrl/mpam_internal.h
@@ -470,7 +470,7 @@ int mpam_msmon_read(struct mpam_component *comp, struct mon_cfg *ctx,
 		    enum mpam_device_features, u64 *val);
 void mpam_msmon_reset_mbwu(struct mpam_component *comp, struct mon_cfg *ctx);
 
-int mpam_get_cpumask_from_cache_id(unsigned long cache_id, u32 cache_level,
+int mpam_get_cpumask_from_cache_id(u32 cache_id, u32 cache_level,
 				   cpumask_t *affinity);
 
 #ifdef CONFIG_RESCTRL_FS

-- 
2.34.1