Re: [PATCH] include/linux/compiler-clang.h: define __naked

From: Nick Desaulniers <ndesaulniers@google.com>
To: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>, Stefan Agner <stefan@agner.ch>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Kees Cook <keescook@chromium.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@kernel.org>,
	Andrey Ryabinin <aryabinin@virtuozzo.com>,
	Will Deacon <will.deacon@arm.com>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	dwmw@amazon.co.uk, Paul Lawrence <paullawrence@google.com>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Dmitry Vyukov <dvyukov@google.com>
Subject: Re: [PATCH] include/linux/compiler-clang.h: define __naked
Date: Thu, 13 Sep 2018 15:20:07 -0700	[thread overview]
Message-ID: <CAKwvOdkgdbn76+jGEwUayGriGn+4GQVLtxkzszkBueP6XuOGLw@mail.gmail.com> (raw)
In-Reply-To: <CANiq72=BE8ygC6r4cJ2TshwOKCEv0C8F2xmpLRhSVMfqq16xUQ@mail.gmail.com>

On Wed, Sep 12, 2018 at 9:03 PM Miguel Ojeda
<miguel.ojeda.sandonis@gmail.com> wrote:
>
> Hi again,
>
> On Wed, Sep 12, 2018 at 6:19 AM, Miguel Ojeda
> <miguel.ojeda.sandonis@gmail.com> wrote:
> >
> > I will do a bigger one tomorrow or so and see if there are any
> > important differences. Regardless of what we do, I will send the
> > __naked patches separately as well (requested by Nick on GitHub).
>
> So I did a comparison with a full allyesconfig between -rc2 and -rc2 +
> v4. I find quite a lot binary differences, but not a single objdump -d
> difference (object file by object file) just by fixing UTS_RELEASE to
> the same value, so I guess that is a very good sign in case someone
> wants to pick the entire series sooner than expected. Regardless, I
> will send the separate __naked patches.
>
> I should note that, at some point in one of my allyesconfig builds I got this:
>
>   UPD     include/generated/compile.h
>   CC      init/version.o
>   AR      init/built-in.a
>   AR      built-in.a
>   LD      vmlinux.o
>   MODPOST vmlinux.o
> ld: drivers/edac/amd64_edac.o(.text+0x200031d2): reloc against
> `__asan_load4_noabort': error 4
> ld: final link failed: Nonrepresentable section on output
> Makefile:1035: recipe for target 'vmlinux' failed
> make: *** [vmlinux] Error 1

+ Dmitry for the KASAN error (Andrey was already cc'ed)

>
> Running make (without cleaning) didn't reproduce it, and the other
> allyesconfig builds didn't suffer any problem either. Maybe my
> hardware is failing, but I wanted to let you know nevertheless.
>
> Cheers,
> Miguel


-- 
Thanks,
~Nick Desaulniers