clone实现

 

#ifdef __ARCH_WANT_SYS_CLONE
#ifdef CONFIG_CLONE_BACKWARDS
SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp,
   int __user *, parent_tidptr,
   unsigned long, tls,
   int __user *, child_tidptr)
#elif defined(CONFIG_CLONE_BACKWARDS2)
SYSCALL_DEFINE5(clone, unsigned long, newsp, unsigned long, clone_flags,
   int __user *, parent_tidptr,
   int __user *, child_tidptr,
   unsigned long, tls)
#elif defined(CONFIG_CLONE_BACKWARDS3)
SYSCALL_DEFINE6(clone, unsigned long, clone_flags, unsigned long, newsp,
  int, stack_size,
  int __user *, parent_tidptr,
  int __user *, child_tidptr,
  unsigned long, tls)
#else
SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp,
   int __user *, parent_tidptr,
   int __user *, child_tidptr,
   unsigned long, tls)
#endif
{
 return _do_fork(clone_flags, newsp, 0, parent_tidptr, child_tidptr, tls);
}
#endif