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// SPDX-License-Identifier: GPL-2.0-only
/*
* Glue code for POLYVAL using ARMv8 Crypto Extensions
*
* Copyright (c) 2007 Nokia Siemens Networks - Mikko Herranen <mh1@iki.fi>
* Copyright (c) 2009 Intel Corp.
* Author: Huang Ying <ying.huang@intel.com>
* Copyright 2021 Google LLC
*/
/*
* Glue code based on ghash-clmulni-intel_glue.c.
*
* This implementation of POLYVAL uses montgomery multiplication accelerated by
* ARMv8 Crypto Extensions instructions to implement the finite field operations.
*/
#include <crypto/algapi.h>
#include <crypto/internal/hash.h>
#include <crypto/internal/simd.h>
#include <crypto/polyval.h>
#include <linux/crypto.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/cpufeature.h>
#include <asm/neon.h>
#include <asm/simd.h>
#define NUM_KEY_POWERS 8
struct polyval_tfm_ctx {
/*
* These powers must be in the order h^8, ..., h^1.
*/
u8 key_powers[NUM_KEY_POWERS][POLYVAL_BLOCK_SIZE];
};
struct polyval_desc_ctx {
u8 buffer[POLYVAL_BLOCK_SIZE];
u32 bytes;
};
asmlinkage void pmull_polyval_update(const struct polyval_tfm_ctx *keys,
const u8 *in, size_t nblocks, u8 *accumulator);
asmlinkage void pmull_polyval_mul(u8 *op1, const u8 *op2);
static void internal_polyval_update(const struct polyval_tfm_ctx *keys,
const u8 *in, size_t nblocks, u8 *accumulator)
{
if (likely(crypto_simd_usable())) {
kernel_neon_begin();
pmull_polyval_update(keys, in, nblocks, accumulator);
kernel_neon_end();
} else {
polyval_update_non4k(keys->key_powers[NUM_KEY_POWERS-1], in,
nblocks, accumulator);
}
}
static void internal_polyval_mul(u8 *op1, const u8 *op2)
{
if (likely(crypto_simd_usable())) {
kernel_neon_begin();
pmull_polyval_mul(op1, op2);
kernel_neon_end();
} else {
polyval_mul_non4k(op1, op2);
}
}
static int polyval_arm64_setkey(struct crypto_shash *tfm,
const u8 *key, unsigned int keylen)
{
struct polyval_tfm_ctx *tctx = crypto_shash_ctx(tfm);
int i;
if (keylen != POLYVAL_BLOCK_SIZE)
return -EINVAL;
memcpy(tctx->key_powers[NUM_KEY_POWERS-1], key, POLYVAL_BLOCK_SIZE);
for (i = NUM_KEY_POWERS-2; i >= 0; i--) {
memcpy(tctx->key_powers[i], key, POLYVAL_BLOCK_SIZE);
internal_polyval_mul(tctx->key_powers[i],
tctx->key_powers[i+1]);
}
return 0;
}
static int polyval_arm64_init(struct shash_desc *desc)
{
struct polyval_desc_ctx *dctx = shash_desc_ctx(desc);
memset(dctx, 0, sizeof(*dctx));
return 0;
}
static int polyval_arm64_update(struct shash_desc *desc,
const u8 *src, unsigned int srclen)
{
struct polyval_desc_ctx *dctx = shash_desc_ctx(desc);
const struct polyval_tfm_ctx *tctx = crypto_shash_ctx(desc->tfm);
u8 *pos;
unsigned int nblocks;
unsigned int n;
if (dctx->bytes) {
n = min(srclen, dctx->bytes);
pos = dctx->buffer + POLYVAL_BLOCK_SIZE - dctx->bytes;
dctx->bytes -= n;
srclen -= n;
while (n--)
*pos++ ^= *src++;
if (!dctx->bytes)
internal_polyval_mul(dctx->buffer,
tctx->key_powers[NUM_KEY_POWERS-1]);
}
while (srclen >= POLYVAL_BLOCK_SIZE) {
/* allow rescheduling every 4K bytes */
nblocks = min(srclen, 4096U) / POLYVAL_BLOCK_SIZE;
internal_polyval_update(tctx, src, nblocks, dctx->buffer);
srclen -= nblocks * POLYVAL_BLOCK_SIZE;
src += nblocks * POLYVAL_BLOCK_SIZE;
}
if (srclen) {
dctx->bytes = POLYVAL_BLOCK_SIZE - srclen;
pos = dctx->buffer;
while (srclen--)
*pos++ ^= *src++;
}
return 0;
}
static int polyval_arm64_final(struct shash_desc *desc, u8 *dst)
{
struct polyval_desc_ctx *dctx = shash_desc_ctx(desc);
const struct polyval_tfm_ctx *tctx = crypto_shash_ctx(desc->tfm);
if (dctx->bytes) {
internal_polyval_mul(dctx->buffer,
tctx->key_powers[NUM_KEY_POWERS-1]);
}
memcpy(dst, dctx->buffer, POLYVAL_BLOCK_SIZE);
return 0;
}
static struct shash_alg polyval_alg = {
.digestsize = POLYVAL_DIGEST_SIZE,
.init = polyval_arm64_init,
.update = polyval_arm64_update,
.final = polyval_arm64_final,
.setkey = polyval_arm64_setkey,
.descsize = sizeof(struct polyval_desc_ctx),
.base = {
.cra_name = "polyval",
.cra_driver_name = "polyval-ce",
.cra_priority = 200,
.cra_blocksize = POLYVAL_BLOCK_SIZE,
.cra_ctxsize = sizeof(struct polyval_tfm_ctx),
.cra_module = THIS_MODULE,
},
};
static int __init polyval_ce_mod_init(void)
{
return crypto_register_shash(&polyval_alg);
}
static void __exit polyval_ce_mod_exit(void)
{
crypto_unregister_shash(&polyval_alg);
}
module_cpu_feature_match(PMULL, polyval_ce_mod_init)
module_exit(polyval_ce_mod_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("POLYVAL hash function accelerated by ARMv8 Crypto Extensions");
MODULE_ALIAS_CRYPTO("polyval");
MODULE_ALIAS_CRYPTO("polyval-ce");
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