Re: [PATCH net-next v6 07/23] zinc: ChaCha20 ARM and ARM64 implementations

Jason A. Donenfeld
2018-09-26T15:50:12Z

On Wed, Sep 26, 2018 at 5:45 PM Jason A. Donenfeld <Jason@zx2c4.com> 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;
}