Exemple #1
0
long arch_prctl(struct task_struct *task, int code, unsigned long __user *addr)
{
	unsigned long *ptr = addr, tmp;
	long ret;
	int pid = task->mm->context.id.u.pid;

	/*
	 * With ARCH_SET_FS (and ARCH_SET_GS is treated similarly to
	 * be safe), we need to call arch_prctl on the host because
	 * setting %fs may result in something else happening (like a
	 * GDT or thread.fs being set instead).  So, we let the host
	 * fiddle the registers and thread struct and restore the
	 * registers afterwards.
	 *
	 * So, the saved registers are stored to the process (this
	 * needed because a stub may have been the last thing to run),
	 * arch_prctl is run on the host, then the registers are read
	 * back.
	 */
	switch (code) {
	case ARCH_SET_FS:
	case ARCH_SET_GS:
		ret = restore_registers(pid, &current->thread.regs.regs);
		if (ret)
			return ret;
		break;
	case ARCH_GET_FS:
	case ARCH_GET_GS:
		/*
		 * With these two, we read to a local pointer and
		 * put_user it to the userspace pointer that we were
		 * given.  If addr isn't valid (because it hasn't been
		 * faulted in or is just bogus), we want put_user to
		 * fault it in (or return -EFAULT) instead of having
		 * the host return -EFAULT.
		 */
		ptr = &tmp;
	}

	ret = os_arch_prctl(pid, code, ptr);
	if (ret)
		return ret;

	switch (code) {
	case ARCH_SET_FS:
		current->thread.arch.fs = (unsigned long) ptr;
		ret = save_registers(pid, &current->thread.regs.regs);
		break;
	case ARCH_SET_GS:
		ret = save_registers(pid, &current->thread.regs.regs);
		break;
	case ARCH_GET_FS:
		ret = put_user(tmp, addr);
		break;
	case ARCH_GET_GS:
		ret = put_user(tmp, addr);
		break;
	}

	return ret;
}
Exemple #2
0
long arch_prctl(struct task_struct *task, int code, unsigned long __user *addr)
{
	unsigned long *ptr = addr, tmp;
	long ret;
	int pid = task->mm->context.id.u.pid;

	/*
                                                             
                                                            
                                                              
                                                             
                                                          
                         
   
                                                           
                                                               
                                                              
         
  */
	switch (code) {
	case ARCH_SET_FS:
	case ARCH_SET_GS:
		ret = restore_registers(pid, &current->thread.regs.regs);
		if (ret)
			return ret;
		break;
	case ARCH_GET_FS:
	case ARCH_GET_GS:
		/*
                                                   
                                                      
                                                        
                                                      
                                                      
                             
   */
		ptr = &tmp;
	}

	ret = os_arch_prctl(pid, code, ptr);
	if (ret)
		return ret;

	switch (code) {
	case ARCH_SET_FS:
		current->thread.arch.fs = (unsigned long) ptr;
		ret = save_registers(pid, &current->thread.regs.regs);
		break;
	case ARCH_SET_GS:
		ret = save_registers(pid, &current->thread.regs.regs);
		break;
	case ARCH_GET_FS:
		ret = put_user(tmp, addr);
		break;
	case ARCH_GET_GS:
		ret = put_user(tmp, addr);
		break;
	}

	return ret;
}