[PATCH] arm: cmpxchg syscall should data abort if page not write or not young

[Po-Yu Chuang]

Dear Russell King,

On Mon, Mar 14, 2011 at 6:40 PM, Russell King - ARM Linux
<linux at arm.linux.org.uk> wrote:
> On Mon, Mar 14, 2011 at 06:28:36PM +0800, Po-Yu Chuang wrote:
>> From: Po-Yu Chuang <ratbert at faraday-tech.com>
>>
>> If the page to cmpxchg is user mode read only (not write)
>> or invalid (not young), we should simulate a data abort first.
>
> No.  If it is not young then it should be made young.  Age is an effect
> of accesses.  It's not a permission.

OK, I will rethink about the not young part.
Thanks for your pointer.

I will resubmit a v2 which contains only the read only check.
It fixes a problem we met with futex.

best regards,
Po-Yu Chuang