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SubjectRe: arm64 kvm built with clang doesn't boot
On Fri, Mar 16, 2018 at 3:13 PM, Mark Rutland <> 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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