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Date:   Thu, 3 Mar 2022 12:35:17 +0000
From:   Mark Brown <broonie@kernel.org>
To:     Marc Zyngier <maz@kernel.org>
Cc:     Ard Biesheuvel <ardb@kernel.org>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        "David S . Miller" <davem@davemloft.net>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] arm64: crypto: Don't allow v8.2 extensions to be used
 with BROKEN_GAS_INST
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References: <20220302165438.1140256-1-broonie@kernel.org>
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On Thu, Mar 03, 2022 at 11:16:28AM +0000, Marc Zyngier wrote:

> Indeed. The only case where the broken GAS .inst has hit us was in
> combination with alternatives (see eb7c11ee3c5c for details). The
> encoding itself is always correct, and it is only the label generation
> that was broken. If we were affected by this, the kernel would simply
> fail to build with these toolchains.

> If this ever happens (because we'd add some extra alternative
> sequences to the crypto code?), we can revisit this. But in the
> meantime, I don't see anything warranting this extra dependency.

Ah, in that case the SVE code should be fine too and there's no issue
with either.  I'd understood the issue to be with the actual instruction
encoding.

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