kernel: spinlock: add assertion to protect K_SPINLOCK

Adds an assertion for the GCC toolchain to check whether the K_SPINLOCK
block was left without unlocking the spinlock, e.g. by calling break,
return or goto.

Signed-off-by: Florian Grandel <fgrandel@code-for-humans.de>

include/zephyr/spinlock.h

@@ -232,6 +232,17 @@ static ALWAYS_INLINE void k_spin_release(struct k_spinlock *l)
 #endif
 }
 
+#if defined(CONFIG_SPIN_VALIDATE) && defined(__GNUC__)
+static ALWAYS_INLINE void z_spin_onexit(k_spinlock_key_t *k)
+{
+ __ASSERT(k->key, "K_SPINLOCK exited with goto, break or return, "
+ "use K_SPINLOCK_BREAK instead.");
+}
+#define K_SPINLOCK_ONEXIT __attribute__((__cleanup__(z_spin_onexit)))
+#else
+#define K_SPINLOCK_ONEXIT
+#endif
+
 /**
  * INTERNAL_HIDDEN @endcond
  */
@@ -286,7 +297,7 @@ static ALWAYS_INLINE void k_spin_release(struct k_spinlock *l)
  * @param lck Spinlock used to guard the enclosed code block.
  */
 #define K_SPINLOCK(lck) \
- for (k_spinlock_key_t __i = {}, __key = k_spin_lock(lck); !__i.key;  \
+ for (k_spinlock_key_t __i K_SPINLOCK_ONEXIT = {}, __key = k_spin_lock(lck); !__i.key; \
  k_spin_unlock(lck, __key), __i.key = 1)
 
 /** @} */