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Date:   Mon, 7 Aug 2023 22:16:58 -0400
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     Florian Weimer <fweimer@redhat.com>,
        Marco Elver <elver@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Kees Cook <keescook@chromium.org>,
        Guenter Roeck <linux@roeck-us.net>,
        Mark Rutland <mark.rutland@arm.com>,
        Marc Zyngier <maz@kernel.org>,
        Oliver Upton <oliver.upton@linux.dev>,
        James Morse <james.morse@arm.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Zenghui Yu <yuzenghui@huawei.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>, Miguel Ojeda <ojeda@kernel.org>,
        linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev,
        linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
        Dmitry Vyukov <dvyukov@google.com>,
        Alexander Potapenko <glider@google.com>,
        kasan-dev@googlegroups.com, linux-toolchains@vger.kernel.org
Subject: Re: [PATCH v2 1/3] compiler_types: Introduce the Clang
 __preserve_most function attribute
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On Mon, 7 Aug 2023 14:31:37 +0200
Peter Zijlstra <peterz@infradead.org> wrote:

> > that this is not a compilation for a module.  Otherwise modules built
> > with a compiler with __preserve_most__ attribute support are
> > incompatible with kernels built with a compiler without that attribute.  
> 
> We have a metric ton of options that can break module ABI. If you're
> daft enough to not build with the exact same compiler and .config you
> get to keep the pieces.

I believe there's enough checks for various compiler options in order to
enable features during the build that trying to load a module built with
another compiler is pretty much guaranteed to fail today.

-- Steve