From: "Jason A. Donenfeld" Subject: Re: [PATCH net-next v6 07/23] zinc: ChaCha20 ARM and ARM64 implementations Date: Wed, 26 Sep 2018 17:49:55 +0200 Message-ID: References: <20180925145622.29959-1-Jason@zx2c4.com> <20180925145622.29959-8-Jason@zx2c4.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Cc: Herbert Xu , Thomas Gleixner , LKML , Netdev , Linux Crypto Mailing List , David Miller , Greg Kroah-Hartman , Samuel Neves , Andrew Lutomirski , Jean-Philippe Aumasson , Russell King - ARM Linux , linux-arm-kernel@lists.infradead.org To: Ard Biesheuvel Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org On Wed, Sep 26, 2018 at 5:45 PM Jason A. Donenfeld wrote: > So what you have in mind is something like calling simd_relax() every > 4096 bytes or so? That was actually pretty easy, putting together both of your suggestions: static inline bool chacha20_arch(struct chacha20_ctx *state, u8 *dst, u8 *src, size_t len, simd_context_t *simd_context) { while (len > PAGE_SIZE) { chacha20_arch(state, dst, src, PAGE_SIZE, simd_context); len -= PAGE_SIZE; src += PAGE_SIZE; dst += PAGE_SIZE; simd_relax(simd_context); } if (IS_ENABLED(CONFIG_KERNEL_MODE_NEON) && chacha20_use_neon && len >= CHACHA20_BLOCK_SIZE * 3 && simd_use(simd_context)) chacha20_neon(dst, src, len, state->key, state->counter); else chacha20_arm(dst, src, len, state->key, state->counter); state->counter[0] += (len + 63) / 64; return true; }