unsigned long pc = (unsigned long) __builtin_return_address(0);
unsigned long pc = 1 | (unsigned long) __builtin_return_address(0);
static inline int _raw_spin_trylock(spinlock_t *lp){	unsigned long pc = (unsigned long) __builtin_return_address(0);	if (likely(_raw_compare_and_swap(&lp->lock, 0, pc) == 0))		return 1;	return _raw_spin_trylock_retry(lp, pc);}