linux-kernel - Re: [PATCH 0/2] Stop generating .eh

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Message-ID: <CAKwvOd=qVmb7UEzUSQ5-MUhpRA9Jpu3fMmmMLGdmydLoJV-kkQ@mail.gmail.com>
Date:   Mon, 24 Feb 2020 12:49:03 -0800
From:   Nick Desaulniers <ndesaulniers@...gle.com>
To:     Arvind Sankar <nivedita@...m.mit.edu>
Cc:     Borislav Petkov <bp@...en8.de>,
        Nathan Chancellor <natechancellor@...il.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>,
        "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        clang-built-linux <clang-built-linux@...glegroups.com>,
        Michael Matz <matz@...e.de>, Fangrui Song <maskray@...gle.com>,
        Kees Cook <keescook@...omium.org>
Subject: Re: [PATCH 0/2] Stop generating .eh_frame sections

On Sun, Feb 23, 2020 at 11:37 AM Arvind Sankar <nivedita@...m.mit.edu> wrote:
>
> In three places in the x86 kernel we are currently generating .eh_frame
> sections only to discard them later via linker script. This is in the
> boot code (setup.elf), the realmode trampoline (realmode.elf) and the
> compressed kernel.
>
> Implement Fangrui and Nick's suggestion [1] to fix KBUILD_CFLAGS by
> adding -fno-asynchronous-unwind-tables to avoid generating .eh_frame
> sections in the first place, rather than discarding it in the linker
> script.
>
> Arvind Sankar (2):
>   arch/x86: Use -fno-asynchronous-unwind-tables to suppress .eh_frame sections
>   arch/x86: Drop unneeded linker script discard of .eh_frame

Thanks for the series! I've left some feedback for a v2. Would you
mind please including a revert of ("x86/boot/compressed: Remove
unnecessary sections from bzImage") in a v2 series?  Our CI being red
through the weekend is no bueno.

>
>  arch/x86/boot/Makefile                | 1 +
>  arch/x86/boot/compressed/Makefile     | 1 +
>  arch/x86/boot/setup.ld                | 1 -
>  arch/x86/kernel/vmlinux.lds.S         | 3 ---
>  arch/x86/realmode/rm/Makefile         | 1 +
>  arch/x86/realmode/rm/realmode.lds.S   | 1 -
>  drivers/firmware/efi/libstub/Makefile | 3 ++-
>  7 files changed, 5 insertions(+), 6 deletions(-)
>
> --
> 2.24.1
>


-- 
Thanks,
~Nick Desaulniers