def sys_mprotect(self, start, size, prot):
perms = perms_from_protflags(prot)<EOL>ret = self.current.memory.mprotect(start, size, perms)<EOL>return <NUM_LIT:0><EOL>
Sets protection on a region of memory. Changes protection for the calling process's
memory page(s) containing any part of the address range in the interval [C{start}, C{start}+C{size}-1].
:rtype: int

:param start: the starting address to change the permissions.
:param size: the size of the portion of memory to change the permissions.
:param prot: the new access permission for the memory.
:return: C{0} on success.