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 <20191002141713.31189-15-ard.biesheuvel@linaro.org> <20191004135750.GA114360@zx2c4.com>
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From:   Ard Biesheuvel <ard.biesheuvel@linaro.org>
Date:   Fri, 4 Oct 2019 16:03:00 +0200
Message-ID: <CAKv+Gu9Gwu=Qzw=+iREro_JHzCWKAiqtbWrnFq8qozYazNn6XA@mail.gmail.com>
Subject: Re: [PATCH v2 14/20] crypto: Curve25519 - generic C library
 implementations and selftest
To:     "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc:     "open list:HARDWARE RANDOM NUMBER GENERATOR CORE" 
        <linux-crypto@vger.kernel.org>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        David Miller <davem@davemloft.net>,
        Greg KH <gregkh@linuxfoundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Samuel Neves <sneves@dei.uc.pt>,
        Dan Carpenter <dan.carpenter@oracle.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Eric Biggers <ebiggers@google.com>,
        Andy Lutomirski <luto@kernel.org>,
        Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Martin Willi <martin@strongswan.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Josh Poimboeuf <jpoimboe@redhat.com>
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On Fri, 4 Oct 2019 at 15:57, Jason A. Donenfeld <Jason@zx2c4.com> wrote:
>
> On Wed, Oct 02, 2019 at 04:17:07PM +0200, Ard Biesheuvel wrote:
> >        - replace .c #includes with Kconfig based object selection
>
> Cool!
>
> > +config CRYPTO_ARCH_HAVE_LIB_CURVE25519
> > +     tristate
> > +
> > +config CRYPTO_ARCH_HAVE_LIB_CURVE25519_BASE
> > +     bool
> > +
> > +config CRYPTO_LIB_CURVE25519
> > +     tristate "Curve25519 scalar multiplication library"
> > +     depends on CRYPTO_ARCH_HAVE_LIB_CURVE25519 || !CRYPTO_ARCH_HAVE_LIB_CURVE25519
>
> a || !a ==> true
>
> Did you mean for one of these to be _BASE? Or is this a Kconfig trick of
> a different variety that's intentional?
>

This ensures that the base module is not builtin when the arch one is
configured as a module, since in that case, the arch code never gets
called.

> > +libcurve25519-y                                      := curve25519-fiat32.o
> > +libcurve25519-$(CONFIG_ARCH_SUPPORTS_INT128) := curve25519-hacl64.o
>
> Nice idea.