Re: [PATCH] mm: provide a fallback for PAGE_KERNEL_RO for architectures

[Luis R. Rodriguez]

On Wed, May 02, 2018 at 12:08:57PM +0200, Geert Uytterhoeven wrote:
> Hi Luis,
> 
> On Sat, Apr 28, 2018 at 2:15 AM, Luis R. Rodriguez <mcgrof@xxxxxxxxxx> wrote:
> > Some architectures do not define PAGE_KERNEL_RO, best we can do
> > for them is to provide a fallback onto PAGE_KERNEL. Remove the
> > hack from the firmware loader and move it onto the asm-generic
> > header, and document while at it the affected architectures
> > which do not have a PAGE_KERNEL_RO:
> >
> >   o alpha
> >   o ia64
> >   o m68k
> >   o mips
> >   o sparc64
> >   o sparc
> >
> > Blessed-by: 0-day
> > Signed-off-by: Luis R. Rodriguez <mcgrof@xxxxxxxxxx>
> 
> I believe the "best we can do" is to add the missing definitions for the
> architectures where the hardware does support it?

True, but we cannot wait for every architecture to implement a feature to then
such generics upstream, specially when we have common places which use that.
Matthew did send a patch to add ia64 support for PAGE_KERNEL_RO, so I'll
respin the patch to add that and also move the other define he suggested.

At least we'd now have a list of documented archs which need further work too.

  Luis