Updated main branch

kernel/feature.c

@@ -0,0 +1,173 @@
+#include "feature.h"
+#include "klog.h" // IWYU pragma: keep
+
+#include <linux/mutex.h>
+
+static const struct ksu_feature_handler *feature_handlers[KSU_FEATURE_MAX];
+
+static DEFINE_MUTEX(feature_mutex);
+
+int ksu_register_feature_handler(const struct ksu_feature_handler *handler)
+{
+    if (!handler) {
+        pr_err("feature: register handler is NULL\n");
+        return -EINVAL;
+    }
+
+    if (handler->feature_id >= KSU_FEATURE_MAX) {
+        pr_err("feature: invalid feature_id %u\n", handler->feature_id);
+        return -EINVAL;
+    }
+
+    if (!handler->get_handler && !handler->set_handler) {
+        pr_err("feature: no handler provided for feature %u\n", handler->feature_id);
+        return -EINVAL;
+    }
+
+    mutex_lock(&feature_mutex);
+
+    if (feature_handlers[handler->feature_id]) {
+        pr_warn("feature: handler for %u already registered, overwriting\n",
+                handler->feature_id);
+    }
+
+    feature_handlers[handler->feature_id] = handler;
+
+    pr_info("feature: registered handler for %s (id=%u)\n",
+            handler->name ? handler->name : "unknown", handler->feature_id);
+
+    mutex_unlock(&feature_mutex);
+    return 0;
+}
+
+int ksu_unregister_feature_handler(u32 feature_id)
+{
+    int ret = 0;
+
+    if (feature_id >= KSU_FEATURE_MAX) {
+        pr_err("feature: invalid feature_id %u\n", feature_id);
+        return -EINVAL;
+    }
+
+    mutex_lock(&feature_mutex);
+
+    if (!feature_handlers[feature_id]) {
+        pr_warn("feature: no handler registered for %u\n", feature_id);
+        ret = -ENOENT;
+        goto out;
+    }
+
+    feature_handlers[feature_id] = NULL;
+
+    pr_info("feature: unregistered handler for id=%u\n", feature_id);
+
+out:
+    mutex_unlock(&feature_mutex);
+    return ret;
+}
+
+int ksu_get_feature(u32 feature_id, u64 *value, bool *supported)
+{
+    int ret = 0;
+    const struct ksu_feature_handler *handler;
+
+    if (feature_id >= KSU_FEATURE_MAX) {
+        pr_err("feature: invalid feature_id %u\n", feature_id);
+        return -EINVAL;
+    }
+
+    if (!value || !supported) {
+        pr_err("feature: invalid parameters\n");
+        return -EINVAL;
+    }
+
+    mutex_lock(&feature_mutex);
+
+    handler = feature_handlers[feature_id];
+
+    if (!handler) {
+        *supported = false;
+        *value = 0;
+        pr_debug("feature: feature %u not supported\n", feature_id);
+        goto out;
+    }
+
+    *supported = true;
+
+    if (!handler->get_handler) {
+        pr_warn("feature: no get_handler for feature %u\n", feature_id);
+        ret = -EOPNOTSUPP;
+        goto out;
+    }
+
+    ret = handler->get_handler(value);
+    if (ret) {
+        pr_err("feature: get_handler for %u failed: %d\n", feature_id, ret);
+    }
+
+out:
+    mutex_unlock(&feature_mutex);
+    return ret;
+}
+
+int ksu_set_feature(u32 feature_id, u64 value)
+{
+    int ret = 0;
+    const struct ksu_feature_handler *handler;
+
+    if (feature_id >= KSU_FEATURE_MAX) {
+        pr_err("feature: invalid feature_id %u\n", feature_id);
+        return -EINVAL;
+    }
+
+    mutex_lock(&feature_mutex);
+
+    handler = feature_handlers[feature_id];
+
+    if (!handler) {
+        pr_err("feature: feature %u not registered\n", feature_id);
+        ret = -EOPNOTSUPP;
+        goto out;
+    }
+
+    if (!handler->set_handler) {
+        pr_warn("feature: no set_handler for feature %u\n", feature_id);
+        ret = -EOPNOTSUPP;
+        goto out;
+    }
+
+    ret = handler->set_handler(value);
+    if (ret) {
+        pr_err("feature: set_handler for %u failed: %d\n", feature_id, ret);
+    }
+
+out:
+    mutex_unlock(&feature_mutex);
+    return ret;
+}
+
+void ksu_feature_init(void)
+{
+    int i;
+
+    for (i = 0; i < KSU_FEATURE_MAX; i++) {
+        feature_handlers[i] = NULL;
+    }
+
+    pr_info("feature: feature management initialized\n");
+}
+
+void ksu_feature_exit(void)
+{
+    int i;
+
+    mutex_lock(&feature_mutex);
+
+    for (i = 0; i < KSU_FEATURE_MAX; i++) {
+        feature_handlers[i] = NULL;
+    }
+
+    mutex_unlock(&feature_mutex);
+
+    pr_info("feature: feature management cleaned up\n");
+}