Re: [Xen-devel] xen/link: Move .data.rel.ro sections into .rodata for final link

[David Woodhouse <dwmw2@xxxxxxxxxxxxx>]

On Sun, 2017-07-30 at 13:50 +0100, Andrew Cooper wrote:
> On 30/07/17 07:16, Jan Beulich wrote:
> > 
> > > 
> > > > 
> > > > > 
> > > > > David Woodhouse <dwmw2@xxxxxxxxxxxxx> 07/20/17 5:22 PM >>>
> > > This includes stuff lke the hypercall tables which we really want
> > > to be read-only. And they were going into .data.read-mostly.
> > Yes, we'd like them to be read-only, but what if EFI properly assigned r/o
> > permissions to the .rodata section when loading xen.efi? We'd then be
> > unable to apply relocations when switching from 1:1 to virtual mappings
> > (see efi_arch_relocate_image()).
> Ah yes.  I'd overlooked that point when considering the ramifications of
> this change.
> 
> efi_arch_relocate_image() should probably do the same as what we do with
> livepatching, and temporarily clear CR0.WP for the duration of the patching.

Hm, efi/mkreloc.c was already emitting relocations in the .rodata
section before this change. Are you saying that was already broken?

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