extern int run_kernel_thread(int (*fn)(void *), void *arg, void **jmp_ptr);
extern int os_map_memory(void *virt, int fd, unsigned long long off,
unsigned long len, int r, int w, int x);
extern int run_kernel_thread(int (*fn)(void *), void *arg, void **jmp_ptr);
extern int os_map_memory(void *virt, int fd, unsigned long long off,
unsigned long len, int r, int w, int x);