Re: [Xen-devel] [PATCH 3/4] x86/linker: add a reloc section to ELF binary

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Wed, Jun 19, 2019 at 06:57:05AM -0600, Jan Beulich wrote:
> >>> On 19.06.19 at 13:02, <roger.pau@xxxxxxxxxx> wrote:
> > If the hypervisor has been built with EFI support (ie: multiboot2).
> > This allows to position the .reloc section correctly in the output
> > binary, or else the linker might place .reloc before the .text
> > section.
> > 
> > Note that the .reloc section is moved before .bss for two reasons: in
> > order for the resulting binary to not contain any section with data
> > after .bss, so that the file size can be smaller than the loaded
> > memory size, and because the data it contains is read-only, so it
> > belongs with the other sections containing read-only data.
> 
> While this may be fine for ELF, I'm afraid it would be calling for
> subtle issues with xen.efi (i.e. the PE binary): There a .reloc
> section is generally expected to come after "normal" data
> sections.

OK, would you like me to leave the .reloc section at the previous
position for EFI builds then?

Or do we prefer to leave .reloc orphaned in the ELF build?

> On the whole, seeing all these adjustments for a linker behavior
> I'm tempted to call buggy, I'm not sure whether we shouldn't
> instead declare this linker version as unusable with Xen. I can't
> imagine that they're going to leave it as it is right now.

I've already submitted a bug report, let's see if this can be fixed
and backported to 8. It's a shame because previous versions of lld
worked just fine, and I would consider this a lld regression.

Thanks, Roger.

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