Re: ARM: static kernel in vmalloc space

Arnd Bergmann
2020-05-12T19:50:20Z

On Tue, May 12, 2020 at 12:48 PM afzal mohammed <afzal.mohd.ma@gmail.com> wrote:
>
> On Mon, May 11, 2020 at 05:29:29PM +0200, Arnd Bergmann wrote:
>
> > What do you currently do with the module address space?
>
> In the current setup, module address space was untouched, i.e. virtual
> address difference b/n text & module space is far greater than 32MB, at
> least > (2+768+16)MB and modules can't be loaded unless ARM_MODULE_PLTS
> is enabled (this was checked now)
>
> > easiest way is to just always put modules into vmalloc space, as we already
> > do with CONFIG_ARM_MODULE_PLTS when the special area gets full,
> > but that could be optimized once the rest works.
>
> Okay

Any idea which bit you want to try next? Creating a raw_copy_{from,to}_user()
based on get_user_pages()/kmap_atomic()/memcpy() is probably a good
next thing to do. I think it can be done one page at a time with only
checking for
get_fs(), access_ok(), and page permissions, while get_user()/put_user()
need to handle a few more corner cases.

Arnd