Re: [PATCH 2/2] arm: apply more __ro_after_init

[Russell King - ARM Linux]

On Wed, Aug 10, 2016 at 09:31:05PM +0200, Arnd Bergmann wrote:
> On Wednesday, August 10, 2016 11:12:53 AM CEST Russell King - ARM Linux wrote:
> > There's the TLS emulation too, but that writes via the vectors mapping
> > at 0xffff0ff0.
> 
> Ok, so that should be safe. Can we change the fiq code to also use the
> high mapping and then take the __ro_after_init patch on top?

We can't - if the kernel is configured without the kuser helpers in
the vectors page, it's mapped read-only.  I'm not sure what the
intersection is between platforms that can have FIQs and platforms
that can disable the kuser helpers.

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