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From:   Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Date:   Tue, 1 Mar 2022 10:28:32 +0100
Message-ID: <CANiq72m0O7ua3F3eqcEru9RuEWHQbG4SumRSoKCi50A8d-+HtA@mail.gmail.com>
Subject: Re: [PATCH] [PATCH v2] AARCH64: Add gcc Shadow Call Stack support
To:     Nick Desaulniers <ndesaulniers@google.com>
Cc:     Dan Li <ashimida@linux.alibaba.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Nathan Chancellor <nathan@kernel.org>,
        Kees Cook <keescook@chromium.org>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Andrew Morton <akpm@linux-foundation.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Sami Tolvanen <samitolvanen@google.com>,
        Nicholas Piggin <npiggin@gmail.com>,
        Guenter Roeck <linux@roeck-us.net>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Miguel Ojeda <ojeda@kernel.org>,
        Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
        Marco Elver <elver@google.com>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        llvm@lists.linux.dev, linux-hardening@vger.kernel.org
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On Mon, Feb 28, 2022 at 11:35 PM Nick Desaulniers
<ndesaulniers@google.com> wrote:
>
> Or simply add a #define for __noscs to include/linux/compiler-gcc.h
> with appropriate guard and leave the existing #ifndef in
> include/linux/compiler_types.h as is.  I'd prefer that when the
> compilers differ in terms of feature detection since it's as explicit
> as possible.

The idea is to avoid differing here to begin with, i.e. to use the
same code for both compilers (only whenever that is possible, of
course), thus having a single `#define` in a single file.

Do you think we will have to change in the future for some reason,
thus needing to split it again?

Cheers,
Miguel