[BUG] Fix deadlocks on disconnected secondary half (#17423)

1 files changed, 30 insertions, 0 deletions

diff --git a/platforms/synchronization_util.h b/platforms/synchronization_util.h
index 3730f271db..81ce074cac 100644
--- a/platforms/synchronization_util.h
+++ b/platforms/synchronization_util.h
@@ -12,3 +12,33 @@ void split_shared_memory_unlock(void);
 inline void split_shared_memory_lock(void){};
 inline void split_shared_memory_unlock(void){};
 #endif
+
+/* GCCs cleanup attribute expects a function with one parameter, which is a
+ * pointer to a type compatible with the variable. As we don't want to expose
+ * the platforms internal mutex type this workaround with auto generated adapter
+ * function is defined */
+#define QMK_DECLARE_AUTOUNLOCK_HELPERS(prefix)                              \
+    inline unsigned prefix##_autounlock_lock_helper(void) {                 \
+        prefix##_lock();                                                    \
+        return 0;                                                           \
+    }                                                                       \
+                                                                            \
+    inline void prefix##_autounlock_unlock_helper(unsigned* unused_guard) { \
+        prefix##_unlock();                                                  \
+    }
+
+/* Convinience macro the automatically generate the correct RAII-style
+ * lock_autounlock function macro */
+#define QMK_DECLARE_AUTOUNLOCK_CALL(prefix) unsigned prefix##_guard __attribute__((unused, cleanup(prefix##_autounlock_unlock_helper))) = prefix##_autounlock_lock_helper
+
+QMK_DECLARE_AUTOUNLOCK_HELPERS(split_shared_memory)
+
+/**
+ * @brief Acquire exclusive access to the split keyboard shared memory, by
+ * calling the platforms `split_shared_memory_lock()` function. The lock is
+ * automatically released by calling the platforms `split_shared_memory_unlock()`
+ * function. This happens when the block where
+ * `split_shared_memory_lock_autounlock()` is called in goes out of scope i.e.
+ * when the enclosing function returns.
+ */
+#define split_shared_memory_lock_autounlock QMK_DECLARE_AUTOUNLOCK_CALL(split_shared_memory)