add: addr_t *kstack = (addr_t *)t->kernel_stack_base; size_t kstack_size = KSTACK_SIZE; addr_t *kstack_top = kstack + kstack_size / sizeof(addr_t) - 2 * 4;   kstack_top -= (31 - 13 + 1) + 1 + 1;   kstack_top--; *kstack_top = (addr_t)start_func;   t->arch_info.sp = (void *)kstack_top;
context: arch_thread_init_kthread_stack(struct thread *t, int (*start_func)(void), void (*entry_func)(void), void (*exit_func)(void)){	return 0;}