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/*
* Poly1305 authenticator algorithm, RFC7539, SIMD glue code
*
* Copyright (C) 2015 Martin Willi
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <crypto/algapi.h>
#include <crypto/internal/hash.h>
#include <crypto/poly1305.h>
#include <linux/crypto.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <asm/fpu/api.h>
#include <asm/simd.h>
struct poly1305_simd_desc_ctx {
struct poly1305_desc_ctx base;
/* derived key u set? */
bool uset;
#ifdef CONFIG_AS_AVX2
/* derived keys r^3, r^4 set? */
bool wset;
#endif
/* derived Poly1305 key r^2 */
u32 u[5];
/* ... silently appended r^3 and r^4 when using AVX2 */
};
asmlinkage void poly1305_block_sse2(u32 *h, const u8 *src,
const u32 *r, unsigned int blocks);
asmlinkage void poly1305_2block_sse2(u32 *h, const u8 *src, const u32 *r,
unsigned int blocks, const u32 *u);
#ifdef CONFIG_AS_AVX2
asmlinkage void poly1305_4block_avx2(u32 *h, const u8 *src, const u32 *r,
unsigned int blocks, const u32 *u);
static bool poly1305_use_avx2;
#endif
static int poly1305_simd_init(struct shash_desc *desc)
{
struct poly1305_simd_desc_ctx *sctx = shash_desc_ctx(desc);
sctx->uset = false;
#ifdef CONFIG_AS_AVX2
sctx->wset = false;
#endif
return crypto_poly1305_init(desc);
}
static void poly1305_simd_mult(u32 *a, const u32 *b)
{
u8 m[POLY1305_BLOCK_SIZE];
memset(m, 0, sizeof(m));
/* The poly1305 block function adds a hi-bit to the accumulator which
* we don't need for key multiplication; compensate for it. */
a[4] -= 1 << 24;
poly1305_block_sse2(a, m, b, 1);
}
static unsigned int poly1305_simd_blocks(struct poly1305_desc_ctx *dctx,
const u8 *src, unsigned int srclen)
{
struct poly1305_simd_desc_ctx *sctx;
unsigned int blocks, datalen;
BUILD_BUG_ON(offsetof(struct poly1305_simd_desc_ctx, base));
sctx = container_of(dctx, struct poly1305_simd_desc_ctx, base);
if (unlikely(!dctx->sset)) {
datalen = crypto_poly1305_setdesckey(dctx, src, srclen);
src += srclen - datalen;
srclen = datalen;
}
#ifdef CONFIG_AS_AVX2
if (poly1305_use_avx2 && srclen >= POLY1305_BLOCK_SIZE * 4) {
if (unlikely(!sctx->wset)) {
if (!sctx->uset) {
memcpy(sctx->u, dctx->r, sizeof(sctx->u));
poly1305_simd_mult(sctx->u, dctx->r);
sctx->uset = true;
}
memcpy(sctx->u + 5, sctx->u, sizeof(sctx->u));
poly1305_simd_mult(sctx->u + 5, dctx->r);
memcpy(sctx->u + 10, sctx->u + 5, sizeof(sctx->u));
poly1305_simd_mult(sctx->u + 10, dctx->r);
sctx->wset = true;
}
blocks = srclen / (POLY1305_BLOCK_SIZE * 4);
poly1305_4block_avx2(dctx->h, src, dctx->r, blocks, sctx->u);
src += POLY1305_BLOCK_SIZE * 4 * blocks;
srclen -= POLY1305_BLOCK_SIZE * 4 * blocks;
}
#endif
if (likely(srclen >= POLY1305_BLOCK_SIZE * 2)) {
if (unlikely(!sctx->uset)) {
memcpy(sctx->u, dctx->r, sizeof(sctx->u));
poly1305_simd_mult(sctx->u, dctx->r);
sctx->uset = true;
}
blocks = srclen / (POLY1305_BLOCK_SIZE * 2);
poly1305_2block_sse2(dctx->h, src, dctx->r, blocks, sctx->u);
src += POLY1305_BLOCK_SIZE * 2 * blocks;
srclen -= POLY1305_BLOCK_SIZE * 2 * blocks;
}
if (srclen >= POLY1305_BLOCK_SIZE) {
poly1305_block_sse2(dctx->h, src, dctx->r, 1);
srclen -= POLY1305_BLOCK_SIZE;
}
return srclen;
}
static int poly1305_simd_update(struct shash_desc *desc,
const u8 *src, unsigned int srclen)
{
struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
unsigned int bytes;
/* kernel_fpu_begin/end is costly, use fallback for small updates */
if (srclen <= 288 || !may_use_simd())
return crypto_poly1305_update(desc, src, srclen);
kernel_fpu_begin();
if (unlikely(dctx->buflen)) {
bytes = min(srclen, POLY1305_BLOCK_SIZE - dctx->buflen);
memcpy(dctx->buf + dctx->buflen, src, bytes);
src += bytes;
srclen -= bytes;
dctx->buflen += bytes;
if (dctx->buflen == POLY1305_BLOCK_SIZE) {
poly1305_simd_blocks(dctx, dctx->buf,
POLY1305_BLOCK_SIZE);
dctx->buflen = 0;
}
}
if (likely(srclen >= POLY1305_BLOCK_SIZE)) {
bytes = poly1305_simd_blocks(dctx, src, srclen);
src += srclen - bytes;
srclen = bytes;
}
kernel_fpu_end();
if (unlikely(srclen)) {
dctx->buflen = srclen;
memcpy(dctx->buf, src, srclen);
}
return 0;
}
static struct shash_alg alg = {
.digestsize = POLY1305_DIGEST_SIZE,
.init = poly1305_simd_init,
.update = poly1305_simd_update,
.final = crypto_poly1305_final,
.descsize = sizeof(struct poly1305_simd_desc_ctx),
.base = {
.cra_name = "poly1305",
.cra_driver_name = "poly1305-simd",
.cra_priority = 300,
.cra_flags = CRYPTO_ALG_TYPE_SHASH,
.cra_blocksize = POLY1305_BLOCK_SIZE,
.cra_module = THIS_MODULE,
},
};
static int __init poly1305_simd_mod_init(void)
{
if (!boot_cpu_has(X86_FEATURE_XMM2))
return -ENODEV;
#ifdef CONFIG_AS_AVX2
poly1305_use_avx2 = boot_cpu_has(X86_FEATURE_AVX) &&
boot_cpu_has(X86_FEATURE_AVX2) &&
cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM, NULL);
alg.descsize = sizeof(struct poly1305_simd_desc_ctx);
if (poly1305_use_avx2)
alg.descsize += 10 * sizeof(u32);
#endif
return crypto_register_shash(&alg);
}
static void __exit poly1305_simd_mod_exit(void)
{
crypto_unregister_shash(&alg);
}
module_init(poly1305_simd_mod_init);
module_exit(poly1305_simd_mod_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
MODULE_DESCRIPTION("Poly1305 authenticator");
MODULE_ALIAS_CRYPTO("poly1305");
MODULE_ALIAS_CRYPTO("poly1305-simd");
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