[PATCH] poly1305: generic C can be faster on chips with slow unaligned access

From: Jason A. Donenfeld
Date: Wed Nov 02 2016 - 13:58:49 EST


On MIPS chips commonly found in inexpensive routers, this makes a big
difference in performance.

Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx>
---
crypto/poly1305_generic.c | 29 ++++++++++++++++++++++++++++-
1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/crypto/poly1305_generic.c b/crypto/poly1305_generic.c
index 2df9835d..186e33d 100644
--- a/crypto/poly1305_generic.c
+++ b/crypto/poly1305_generic.c
@@ -65,11 +65,24 @@ EXPORT_SYMBOL_GPL(crypto_poly1305_setkey);
static void poly1305_setrkey(struct poly1305_desc_ctx *dctx, const u8 *key)
{
/* r &= 0xffffffc0ffffffc0ffffffc0fffffff */
+#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
dctx->r[0] = (le32_to_cpuvp(key + 0) >> 0) & 0x3ffffff;
dctx->r[1] = (le32_to_cpuvp(key + 3) >> 2) & 0x3ffff03;
dctx->r[2] = (le32_to_cpuvp(key + 6) >> 4) & 0x3ffc0ff;
dctx->r[3] = (le32_to_cpuvp(key + 9) >> 6) & 0x3f03fff;
dctx->r[4] = (le32_to_cpuvp(key + 12) >> 8) & 0x00fffff;
+#else
+ u32 t0, t1, t2, t3;
+ t0 = le32_to_cpuvp(key + 0);
+ t1 = le32_to_cpuvp(key + 4);
+ t2 = le32_to_cpuvp(key + 8);
+ t3 = le32_to_cpuvp(key + 12);
+ dctx->r[0] = t0 & 0x3ffffff; t0 >>= 26; t0 |= t1 << 6;
+ dctx->r[1] = t0 & 0x3ffff03; t1 >>= 20; t1 |= t2 << 12;
+ dctx->r[2] = t1 & 0x3ffc0ff; t2 >>= 14; t2 |= t3 << 18;
+ dctx->r[3] = t2 & 0x3f03fff; t3 >>= 8;
+ dctx->r[4] = t3 & 0x00fffff;
+#endif
}

static void poly1305_setskey(struct poly1305_desc_ctx *dctx, const u8 *key)
@@ -109,6 +122,9 @@ static unsigned int poly1305_blocks(struct poly1305_desc_ctx *dctx,
u32 s1, s2, s3, s4;
u32 h0, h1, h2, h3, h4;
u64 d0, d1, d2, d3, d4;
+#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
+ u32 t0, t1, t2, t3;
+#endif
unsigned int datalen;

if (unlikely(!dctx->sset)) {
@@ -135,13 +151,24 @@ static unsigned int poly1305_blocks(struct poly1305_desc_ctx *dctx,
h4 = dctx->h[4];

while (likely(srclen >= POLY1305_BLOCK_SIZE)) {
-
/* h += m[i] */
+#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
h0 += (le32_to_cpuvp(src + 0) >> 0) & 0x3ffffff;
h1 += (le32_to_cpuvp(src + 3) >> 2) & 0x3ffffff;
h2 += (le32_to_cpuvp(src + 6) >> 4) & 0x3ffffff;
h3 += (le32_to_cpuvp(src + 9) >> 6) & 0x3ffffff;
h4 += (le32_to_cpuvp(src + 12) >> 8) | hibit;
+#else
+ t0 = le32_to_cpuvp(src + 0);
+ t1 = le32_to_cpuvp(src + 4);
+ t2 = le32_to_cpuvp(src + 8);
+ t3 = le32_to_cpuvp(src + 12);
+ h0 += t0 & 0x3ffffff;
+ h1 += sr((((u64)t1 << 32) | t0), 26) & 0x3ffffff;
+ h2 += sr((((u64)t2 << 32) | t1), 20) & 0x3ffffff;
+ h3 += sr((((u64)t3 << 32) | t2), 14) & 0x3ffffff;
+ h4 += (t3 >> 8) | hibit;
+#endif

/* h *= r */
d0 = mlt(h0, r0) + mlt(h1, s4) + mlt(h2, s3) +
--
2.10.2