ARM64: Domain Equivalent support in ARMv8

[Ganapat Rao P Kulkarni]

Thanks.

On Thu, Dec 12, 2013 at 5:25 PM, Catalin Marinas
<catalin.marinas at arm.com> wrote:
> On Thu, Dec 12, 2013 at 07:48:19AM +0000, Ganapat Rao P Kulkarni wrote:
>> On Tue, Dec 10, 2013 at 1:17 PM, Ganapat Rao P Kulkarni
>> <gpkulkarni at gmail.com> wrote:
>> > I want to make kernel code ( all sections/blocks mapped to kernel
>> > code) as RO and change to R/W,  when ever hot-patch of kernel code is
>> > required.
>> > Also, R/W access changes should be available/visible to the core which
>> > sets R/W and all other cores continue to have RO access.
>> >
>> > This was easily done using Domain feature(by making Kernel Domain as
>> > Manager, using DACR) on ARMv7.
>> > However, on ARMv8, i see there is no domain support(in AARCH64) and
>> > not able to find the alternative optimal way.
>
> Note that even on ARMv7, if you use LPAE domains are no longer
> available.
>
> So I'm not aware of any way other than creating a temporary mapping in a
> per-CPU pgd. You could use a low address and TTBR0 so that it doesn't
> interfere with the real kernel mapping.
>
> --
> Catalin



-- 
regards,
Ganapat