Re: Query regarding Linux Arm pagetable setup

On Thu, May 5, 2016 at 10:43 PM, Catalin Marinas
<[email protected]> wrote:
> On Thu, May 05, 2016 at 06:00:38PM +0100, Russell King - ARM Linux wrote:
>> On Thu, May 05, 2016 at 05:59:01PM +0100, Catalin Marinas wrote:
>> > On Thu, May 05, 2016 at 05:04:57PM +0100, Russell King - ARM Linux wrote:
>> > > On Thu, May 05, 2016 at 04:17:08PM +0530, Dushyant Behl wrote:
>> > > > Also are there any other kernel pages which are marked with similar
>> > > > user bit and read only permissions in the pagetables with possible
>> > > > aliasing in the kernel's address space too?
>> > >
>> > > No.
>> >
>> > Actually, most read-only user pages (e.g. mmap'ed code) have an alias in
>> > the kernel linear mapping or temporarily in highmem (after kmap).
>>
>> If you want to be strict about it, all pages can end up in that state.
>>
>> I assumed, however, that the OP was asking about pages similar to the
>> special vector page.
>
> That was my first thought as well but given that we don't know the
> background to this question, I think it's better to state the other
> cases (maybe OP is trying to work around a hardware bug affecting page
> permission, you never know; I hope not).

Sorry for not being clear I actually wanted to know about pages similar to the
special vector pages. Thanks for the explanation.

Thanks,
Dushyant