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crypto: arm64/ghash-ce - add non-SIMD scalar fallback

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The arm64 kernel will shortly disallow nested kernel mode NEON, so
add a fallback to scalar C code that can be invoked in that case.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Ard Biesheuvel 2017-07-24 11:28:05 +01:00 committed by Herbert Xu
parent 45fe93dff2
commit 6d6254d728
2 changed files with 43 additions and 9 deletions
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3
arch/arm64/crypto/Kconfig
View File

@ -28,8 +28,9 @@ config CRYPTO_SHA2_ARM64_CE
config CRYPTO_GHASH_ARM64_CE
tristate "GHASH (for GCM chaining mode) using ARMv8 Crypto Extensions"
depends on ARM64 && KERNEL_MODE_NEON
depends on KERNEL_MODE_NEON
select CRYPTO_HASH
select CRYPTO_GF128MUL
config CRYPTO_CRCT10DIF_ARM64_CE
tristate "CRCT10DIF digest algorithm using PMULL instructions"

47
arch/arm64/crypto/ghash-ce-glue.c
View File

@ -1,7 +1,7 @@
/*
* Accelerated GHASH implementation with ARMv8 PMULL instructions.
*
* Copyright (C) 2014 Linaro Ltd. <ard.biesheuvel@linaro.org>
* Copyright (C) 2014 - 2017 Linaro Ltd. <ard.biesheuvel@linaro.org>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published
@ -9,7 +9,9 @@
*/
#include <asm/neon.h>
#include <asm/simd.h>
#include <asm/unaligned.h>
#include <crypto/gf128mul.h>
#include <crypto/internal/hash.h>
#include <linux/cpufeature.h>
#include <linux/crypto.h>
@ -25,6 +27,7 @@ MODULE_LICENSE("GPL v2");
struct ghash_key {
u64 a;
u64 b;
be128 k;
};
struct ghash_desc_ctx {
@ -44,6 +47,36 @@ static int ghash_init(struct shash_desc *desc)
return 0;
}
static void ghash_do_update(int blocks, u64 dg[], const char *src,
struct ghash_key *key, const char *head)
{
if (likely(may_use_simd())) {
kernel_neon_begin();
pmull_ghash_update(blocks, dg, src, key, head);
kernel_neon_end();
} else {
be128 dst = { cpu_to_be64(dg[1]), cpu_to_be64(dg[0]) };
do {
const u8 *in = src;
if (head) {
in = head;
blocks++;
head = NULL;
} else {
src += GHASH_BLOCK_SIZE;
}
crypto_xor((u8 *)&dst, in, GHASH_BLOCK_SIZE);
gf128mul_lle(&dst, &key->k);
} while (--blocks);
dg[0] = be64_to_cpu(dst.b);
dg[1] = be64_to_cpu(dst.a);
}
}
static int ghash_update(struct shash_desc *desc, const u8 *src,
unsigned int len)
{
@ -67,10 +100,9 @@ static int ghash_update(struct shash_desc *desc, const u8 *src,
blocks = len / GHASH_BLOCK_SIZE;
len %= GHASH_BLOCK_SIZE;
kernel_neon_begin_partial(8);
pmull_ghash_update(blocks, ctx->digest, src, key,
ghash_do_update(blocks, ctx->digest, src, key,
partial ? ctx->buf : NULL);
kernel_neon_end();
src += blocks * GHASH_BLOCK_SIZE;
partial = 0;
}
@ -89,9 +121,7 @@ static int ghash_final(struct shash_desc *desc, u8 *dst)
memset(ctx->buf + partial, 0, GHASH_BLOCK_SIZE - partial);
kernel_neon_begin_partial(8);
pmull_ghash_update(1, ctx->digest, ctx->buf, key, NULL);
kernel_neon_end();
ghash_do_update(1, ctx->digest, ctx->buf, key, NULL);
}
put_unaligned_be64(ctx->digest[1], dst);
put_unaligned_be64(ctx->digest[0], dst + 8);
@ -111,6 +141,9 @@ static int ghash_setkey(struct crypto_shash *tfm,
return -EINVAL;
}
/* needed for the fallback */
memcpy(&key->k, inkey, GHASH_BLOCK_SIZE);
/* perform multiplication by 'x' in GF(2^128) */
b = get_unaligned_be64(inkey);
a = get_unaligned_be64(inkey + 8);