From: Herbert Xu <herbert@gondor.apana.org.au>
To: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-rt-users@vger.kernel.org,
Eric Biggers <ebiggers@google.com>,
Ard Biesheuvel <ardb@kernel.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
stable@vger.kernel.org
Subject: Re: [PATCH crypto-stable v3 1/2] crypto: arch/lib - limit simd usage to 4k chunks
Date: Thu, 30 Apr 2020 15:30:49 +1000 [thread overview]
Message-ID: <20200430053049.GA11838@gondor.apana.org.au> (raw)
In-Reply-To: <20200422231854.675965-1-Jason@zx2c4.com>
On Wed, Apr 22, 2020 at 05:18:53PM -0600, Jason A. Donenfeld wrote:
> The initial Zinc patchset, after some mailing list discussion, contained
> code to ensure that kernel_fpu_enable would not be kept on for more than
> a 4k chunk, since it disables preemption. The choice of 4k isn't totally
> scientific, but it's not a bad guess either, and it's what's used in
> both the x86 poly1305, blake2s, and nhpoly1305 code already (in the form
> of PAGE_SIZE, which this commit corrects to be explicitly 4k for the
> former two).
>
> Ard did some back of the envelope calculations and found that
> at 5 cycles/byte (overestimate) on a 1ghz processor (pretty slow), 4k
> means we have a maximum preemption disabling of 20us, which Sebastian
> confirmed was probably a good limit.
>
> Unfortunately the chunking appears to have been left out of the final
> patchset that added the glue code. So, this commit adds it back in.
>
> Fixes: 84e03fa39fbe ("crypto: x86/chacha - expose SIMD ChaCha routine as library function")
> Fixes: b3aad5bad26a ("crypto: arm64/chacha - expose arm64 ChaCha routine as library function")
> Fixes: a44a3430d71b ("crypto: arm/chacha - expose ARM ChaCha routine as library function")
> Fixes: d7d7b8535662 ("crypto: x86/poly1305 - wire up faster implementations for kernel")
> Fixes: f569ca164751 ("crypto: arm64/poly1305 - incorporate OpenSSL/CRYPTOGAMS NEON implementation")
> Fixes: a6b803b3ddc7 ("crypto: arm/poly1305 - incorporate OpenSSL/CRYPTOGAMS NEON implementation")
> Fixes: ed0356eda153 ("crypto: blake2s - x86_64 SIMD implementation")
> Cc: Eric Biggers <ebiggers@google.com>
> Cc: Ard Biesheuvel <ardb@kernel.org>
> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> Cc: stable@vger.kernel.org
> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
> ---
> Changes v2->v3:
> - [Eric] Split nhpoly1305 changes into separate commit, since it's not
> related to the library interface.
>
> Changes v1->v2:
> - [Ard] Use explicit 4k chunks instead of PAGE_SIZE.
> - [Eric] Prefer do-while over for (;;).
>
> arch/arm/crypto/chacha-glue.c | 14 +++++++++++---
> arch/arm/crypto/poly1305-glue.c | 15 +++++++++++----
> arch/arm64/crypto/chacha-neon-glue.c | 14 +++++++++++---
> arch/arm64/crypto/poly1305-glue.c | 15 +++++++++++----
> arch/x86/crypto/blake2s-glue.c | 10 ++++------
> arch/x86/crypto/chacha_glue.c | 14 +++++++++++---
> arch/x86/crypto/poly1305_glue.c | 13 ++++++-------
> 7 files changed, 65 insertions(+), 30 deletions(-)
All applied. Thanks.
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
prev parent reply other threads:[~2020-04-30 5:31 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200420075711.2385190-1-Jason@zx2c4.com>
[not found] ` <20200422040415.GA2881@sol.localdomain>
2020-04-22 7:23 ` [PATCH crypto-stable] crypto: arch/lib - limit simd usage to PAGE_SIZE chunks Ard Biesheuvel
2020-04-22 7:38 ` Jason A. Donenfeld
2020-04-22 11:28 ` Sebastian Andrzej Siewior
2020-04-22 19:35 ` Jason A. Donenfeld
2020-04-22 20:03 ` [PATCH crypto-stable v2] crypto: arch - limit simd usage to 4k chunks Jason A. Donenfeld
2020-04-22 22:39 ` Eric Biggers
2020-04-22 23:09 ` Jason A. Donenfeld
2020-04-22 23:18 ` [PATCH crypto-stable v3 1/2] crypto: arch/lib " Jason A. Donenfeld
2020-04-22 23:18 ` [PATCH crypto-stable v3 2/2] crypto: arch/nhpoly1305 - process in explicit " Jason A. Donenfeld
2020-04-23 20:39 ` Eric Biggers
2020-04-23 7:18 ` [PATCH crypto-stable v3 1/2] crypto: arch/lib - limit simd usage to " Ard Biesheuvel
2020-04-23 7:40 ` Christophe Leroy
2020-04-23 7:47 ` Ard Biesheuvel
2020-04-23 18:42 ` Greg KH
2020-04-23 18:47 ` Ard Biesheuvel
2020-04-23 20:23 ` Eric Biggers
2020-04-23 20:49 ` Ard Biesheuvel
2020-04-28 23:09 ` Jason A. Donenfeld
2020-04-30 5:30 ` Herbert Xu [this message]
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