Changing the page attributes

[Arun KS]

Hello Mulyadi,

On Tue, Jul 10, 2012 at 9:42 PM, Mulyadi Santosa
<mulyadi.santosa at gmail.com> wrote:
> Hi..
>
> On Tue, Jul 10, 2012 at 6:51 PM, Arun KS <getarunks at gmail.com> wrote:
>> Hello Experts,
>>
>> I have a requirement to change __log_buf memory(kernel printk buffer)
>> as non cacheable memory.
>> How can I change the page attributes for changing cache policy to non cacheable?
>
> I just can give short clue. I think somehow you must find its PTE
> entry...there, IIRC there is page attribute that can be changed to
> make it uncacheable.
>
> cross check the Intel processor manual for further clarification (if
> it's indeed x86 arch)

__log_buf size is 512KB and PTE is mapped to a 1MB section. So if I
change the attribute for this 1MB section, lot of other stuffs(in this
1MB bss section) will also become non-cachable. Looks like it is not
possible unless my __log_buf is 1MB in size.
Or I need to create another section like .init, .data, .bss and create
4KB pages(with two levels of Page Tables) instead of 1M section.

My  arch is arm-v7

Thanks,
Arun
>
> --
> regards,
>
> Mulyadi Santosa
> Freelance Linux trainer and consultant
>
> blog: the-hydra.blogspot.com
> training: mulyaditraining.blogspot.com