unsigned long pc = (unsigned long) __builtin_return_address(0);
unsigned long pc = 1 | (unsigned long) __builtin_return_address(0);
static inline void _raw_spin_lock(spinlock_t *lp){	unsigned long pc = (unsigned long) __builtin_return_address(0);	if (unlikely(_raw_compare_and_swap(&lp->lock, 0, pc) != 0))		_raw_spin_lock_wait(lp, pc);}