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Date: Mon, 20 Nov 2017 14:43:06 +0000
From: Mark Rutland <mark.rutland@arm.com>
To: Sami Tolvanen <samitolvanen@google.com>
Cc: Andi Kleen <ak@linux.intel.com>, Kees Cook <keescook@chromium.org>,
        Ard Biesheuvel <ard.biesheuvel@linaro.org>,
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        Maxim Kuvyrkov <maxim.kuvyrkov@linaro.org>
Subject: Re: [PATCH v2 06/18] arm64: kvm: use -fno-jump-tables with clang
Message-ID: <20171120144306.z5uyeyectmce6plu@lakrids.cambridge.arm.com>
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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.