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SubjectRe: arm64 kvm built with clang doesn't boot
On Fri, Mar 16, 2018 at 3:13 PM, Mark Rutland <mark.rutland@arm.com> wrote:
> I think that patch is our best bet currently, but to save ourselves pain
> in future it would be *really* nice if GCC and clang could provide an
> option line -fno-absolute-addressing that would implicitly disable any
> feature that would generate an absolute address as jump tables do.
>

Let me know if you want me to mail that patch again.

Perhaps Nick can comment on whether something like
-fno-absolute-addressing would be feasible in clang. Although even if
it gets implemented, it won't fix the already released clang versions.

> With v4.15 (and clang 5.0.0), I did not have to disable jump labels to
> get a kernel booting on a Juno platform, though I did have to pass
> -fno-jump-tables to the hyp code.
>
> Which kernel version and clang version are you using?

I've rechecked and I think I was wrong here. I disabled
COFNIG_JUMP_LABEL while trying to get the kernel booting before I
added the kvm flags. It seems it's not needed after all.

But just for the reference, I'm using 4.16-rc4 with a patch to fix
SMCCC issues that you mentioned. As for clang, I'm using LLVM revision
325711 (a couple of weeks old).

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