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From:   Andy Lutomirski <luto@amacapital.net>
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Subject: Re: [PATCH 05/15] x86: Implement function_nocfi
Date:   Mon, 19 Apr 2021 10:46:20 -0700
Message-Id: <2C6F783A-8337-48FE-86F3-5871BADF7BC2@amacapital.net>
References: <c0af9b5811cf4066b7297196bc46456f@AcuMS.aculab.com>
Cc:     Andy Lutomirski <luto@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Kees Cook <keescook@chromium.org>,
        Borislav Petkov <bp@alien8.de>,
        Sami Tolvanen <samitolvanen@google.com>,
        X86 ML <x86@kernel.org>, Josh Poimboeuf <jpoimboe@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Sedat Dilek <sedat.dilek@gmail.com>,
        linux-hardening@vger.kernel.org,
        LKML <linux-kernel@vger.kernel.org>,
        clang-built-linux <clang-built-linux@googlegroups.com>
In-Reply-To: <c0af9b5811cf4066b7297196bc46456f@AcuMS.aculab.com>
To:     David Laight <David.Laight@aculab.com>
Precedence: bulk


> On Apr 19, 2021, at 8:26 AM, David Laight <David.Laight@aculab.com> wrote:=

>=20
> =EF=BB=BFFrom: Andy Lutomirski
>> Sent: 18 April 2021 01:12
> ..
>> Slightly more complicated:
>>=20
>> struct opaque_symbol;
>> extern struct opaque_symbol entry_SYSCALL_64;
>>=20
>> The opaque_symbol variant avoids any possible confusion over the weird
>> status of arrays in C, and it's hard to misuse, since struct
>> opaque_symbol is an incomplete type.
>=20
> Maybe:
>=20
> s/opaque_symbol/entry_SYSCALL_64/
>=20

Cute. OTOH, I=E2=80=99m not sure whether that has much benefit, and having a=
 single type for all of this allows it to be declared just once.  I suppose t=
he magic could be wrapped in a macro, though.

>    David
>=20
> -
> Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1=
PT, UK
> Registration No: 1397386 (Wales)