Question: how to make one page readonly on ARM

[晁永生]

2012/2/16 Russell King - ARM Linux <linux at arm.linux.org.uk>:
> On Thu, Feb 16, 2012 at 12:54:27PM +0800, 晁永生 wrote:
>> Hi,
>> I get one page by __get_free_page and can make it readonly by
>> set_memory_ro on X86,
>> but how to do this on ARM?
>
> You can't, because we map all kernel space with 1MB section mappings.

sorry, I don't quite understand. I am kernel newbie.
Do you mean that if I want to make one memory region readonly, it has
to be in MB unit?
Does ARM kernel have any functions similar to set_memory_ro?

-- 
Thanks a lot!