15e64ef652
Add a lightweight spinlock check which uses only two instructions per spinlock call. It detects if a spinlock has been trashed by some memory corruption and then halts the kernel. It will not detect uninitialized spinlocks, for which CONFIG_DEBUG_SPINLOCK needs to be enabled. This lightweight spinlock check shouldn't influence runtime, so it's safe to enable it by default. The __ARCH_SPIN_LOCK_UNLOCKED_VAL constant has been choosen small enough to be able to be loaded by one LDI assembler statement. Signed-off-by: Helge Deller <deller@gmx.de>