linux-kernel - Re: [PATCH v7 15/17] KVM: arm64: disable LTO for the nVHE directory

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Message-ID: <CABCJKudwt6xDUMADRjXU04bxZFFWOFOs_26TJGHV_vnP8Qs5Jw@mail.gmail.com>
Date:   Mon, 23 Nov 2020 10:34:16 -0800
From:   Sami Tolvanen <samitolvanen@...gle.com>
To:     David Brazdil <dbrazdil@...gle.com>
Cc:     Masahiro Yamada <masahiroy@...nel.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        Will Deacon <will@...nel.org>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Paul E. McKenney" <paulmck@...nel.org>,
        Kees Cook <keescook@...omium.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        clang-built-linux <clang-built-linux@...glegroups.com>,
        Kernel Hardening <kernel-hardening@...ts.openwall.com>,
        linux-arch <linux-arch@...r.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        linux-kbuild <linux-kbuild@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>, linux-pci@...r.kernel.org
Subject: Re: [PATCH v7 15/17] KVM: arm64: disable LTO for the nVHE directory

On Mon, Nov 23, 2020 at 2:21 AM David Brazdil <dbrazdil@...gle.com> wrote:
>
> Hey Sami,
>
> On Wed, Nov 18, 2020 at 02:07:29PM -0800, Sami Tolvanen wrote:
> > We use objcopy to manipulate ELF binaries for the nVHE code,
> > which fails with LTO as the compiler produces LLVM bitcode
> > instead. Disable LTO for this code to allow objcopy to be used.
>
> We now partially link the nVHE code (generating machine code) before objcopy,
> so I think you should be able to drop this patch now. Tried building your
> branch without it, ran a couple of unit tests and all seems fine.

Great, thanks for testing this, David! I'll drop this patch from v8.

Sami