powerpc/mm: Allow user space to map rtas_rmo_buf

[Michael Ellerman]

On Thu, 2016-21-01 at 16:15:31 UTC, Vasant Hegde wrote:
> With commit 90a545e9 (restrict /dev/mem to idle io memory ranges) mapping
> rtas_rmo_buf from user space is failing. Hence we are not able to make
> RTAS syscall.
> 
> This patch calls page_is_rtas_user_buf before calling iomem_is_exclusive
> in  devmem_is_allowed(). This will allow user space to map rtas_rmo_buf
> and we are able to make RTAS syscall.
> 
> Reported-by: Bharata B Rao <bharata at linux.vnet.ibm.com>
> CC: Dan Williams <dan.j.williams at intel.com>
> CC: Nathan Fontenot <nfont at linux.vnet.ibm.com>
> CC: Michael Ellerman <mpe at ellerman.id.au>
> Signed-off-by: Vasant Hegde <hegdevasant at linux.vnet.ibm.com>
> Acked-by: Dan Williams <dan.j.williams at intel.com>

Applied to powerpc fixes, thanks.

https://git.kernel.org/powerpc/c/e256caa7d0515e301f8c8c6e7d

cheers