Re: [PATCH v2 06/18] arm64: kvm: use -fno-jump-tables with clang

From: Mark Rutland
Date: Mon Nov 20 2017 - 09:43:16 EST


On Mon, Nov 20, 2017 at 02:41:47PM +0000, Mark Rutland wrote:
> On Wed, Nov 15, 2017 at 01:34:16PM -0800, Sami Tolvanen wrote:
> > Use -fno-jump-tables to make sure clang doesn't generate branches
> > to EL1 virtual addresses.
>
> Are there any other reasons that clang might generate absolute
> references/relocations?
>
> It would be nice if there was the option to disable that more generally,
> rather than disabling individual optimizations. Is there any PIC/PIE
> option that we could use?
>
> We might need something simnilar for GCC, even if we're not seeing
> problems today.

... and likewise for the EFI stub, which needs to be
position-independent much like the hyp code.

Thanks,
Mark.