[PATCH 4.19 26/32] crypto: vmx - ghash: do nosimd fallback manually

Greg Kroah-Hartman
2019-06-03T09:18:26Z

From: Daniel Axtens <dja@axtens.net>

commit 357d065a44cdd77ed5ff35155a989f2a763e96ef upstream.

VMX ghash was using a fallback that did not support interleaving simd
and nosimd operations, leading to failures in the extended test suite.

If I understood correctly, Eric's suggestion was to use the same
data format that the generic code uses, allowing us to call into it
with the same contexts. I wasn't able to get that to work - I think
there's a very different key structure and data layout being used.

So instead steal the arm64 approach and perform the fallback
operations directly if required.

Fixes: cc333cd68dfa ("crypto: vmx - Adding GHASH routines for VMX module")
Cc: stable@vger.kernel.org # v4.1+
Reported-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Daniel Axtens <dja@axtens.net>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/crypto/vmx/ghash.c | 212 ++++++++++++++++++---------------------------
1 file changed, 86 insertions(+), 126 deletions(-)

--- a/drivers/crypto/vmx/ghash.c
+++ b/drivers/crypto/vmx/ghash.c
@@ -1,22 +1,14 @@
+// SPDX-License-Identifier: GPL-2.0
/**
* GHASH routines supporting VMX instructions on the Power 8
*
- * Copyright (C) 2015 International Business Machines Inc.
- *
- * 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; version 2 only.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ * Copyright (C) 2015, 2019 International Business Machines Inc.
*
* Author: Marcelo Henrique Cerri <mhcerri@br.ibm.com>
+ *
+ * Extended by Daniel Axtens <dja@axtens.net> to replace the fallback
+ * mechanism. The new approach is based on arm64 code, which is:
+ * Copyright (C) 2014 - 2018 Linaro Ltd. <ard.biesheuvel@linaro.org>
*/

#include <linux/types.h>
@@ -39,71 +31,25 @@ void gcm_ghash_p8(u64 Xi[2], const u128
const u8 *in, size_t len);

struct p8_ghash_ctx {
+ /* key used by vector asm */
u128 htable[16];
- struct crypto_shash *fallback;
+ /* key used by software fallback */
+ be128 key;
};

struct p8_ghash_desc_ctx {
u64 shash[2];
u8 buffer[GHASH_DIGEST_SIZE];
int bytes;
- struct shash_desc fallback_desc;
};

-static int p8_ghash_init_tfm(struct crypto_tfm *tfm)
-{
- const char *alg = "ghash-generic";
- struct crypto_shash *fallback;
- struct crypto_shash *shash_tfm = __crypto_shash_cast(tfm);
- struct p8_ghash_ctx *ctx = crypto_tfm_ctx(tfm);
-
- fallback = crypto_alloc_shash(alg, 0, CRYPTO_ALG_NEED_FALLBACK);
- if (IS_ERR(fallback)) {
- printk(KERN_ERR
- "Failed to allocate transformation for '%s': %ld\n",
- alg, PTR_ERR(fallback));
- return PTR_ERR(fallback);
- }
-
- crypto_shash_set_flags(fallback,
- crypto_shash_get_flags((struct crypto_shash
- *) tfm));
-
- /* Check if the descsize defined in the algorithm is still enough. */
- if (shash_tfm->descsize < sizeof(struct p8_ghash_desc_ctx)
- + crypto_shash_descsize(fallback)) {
- printk(KERN_ERR
- "Desc size of the fallback implementation (%s) does not match the expected value: %lu vs %u\n",
- alg,
- shash_tfm->descsize - sizeof(struct p8_ghash_desc_ctx),
- crypto_shash_descsize(fallback));
- return -EINVAL;
- }
- ctx->fallback = fallback;
-
- return 0;
-}
-
-static void p8_ghash_exit_tfm(struct crypto_tfm *tfm)
-{
- struct p8_ghash_ctx *ctx = crypto_tfm_ctx(tfm);
-
- if (ctx->fallback) {
- crypto_free_shash(ctx->fallback);
- ctx->fallback = NULL;
- }
-}
-
static int p8_ghash_init(struct shash_desc *desc)
{
- struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(desc->tfm));
struct p8_ghash_desc_ctx *dctx = shash_desc_ctx(desc);

dctx->bytes = 0;
memset(dctx->shash, 0, GHASH_DIGEST_SIZE);
- dctx->fallback_desc.tfm = ctx->fallback;
- dctx->fallback_desc.flags = desc->flags;
- return crypto_shash_init(&dctx->fallback_desc);
+ return 0;
}

static int p8_ghash_setkey(struct crypto_shash *tfm, const u8 *key,
@@ -121,7 +67,51 @@ static int p8_ghash_setkey(struct crypto
disable_kernel_vsx();
pagefault_enable();
preempt_enable();
- return crypto_shash_setkey(ctx->fallback, key, keylen);
+
+ memcpy(&ctx->key, key, GHASH_BLOCK_SIZE);
+
+ return 0;
+}
+
+static inline void __ghash_block(struct p8_ghash_ctx *ctx,
+ struct p8_ghash_desc_ctx *dctx)
+{
+ if (!IN_INTERRUPT) {
+ preempt_disable();
+ pagefault_disable();
+ enable_kernel_vsx();
+ gcm_ghash_p8(dctx->shash, ctx->htable,
+ dctx->buffer, GHASH_DIGEST_SIZE);
+ disable_kernel_vsx();
+ pagefault_enable();
+ preempt_enable();
+ } else {
+ crypto_xor((u8 *)dctx->shash, dctx->buffer, GHASH_BLOCK_SIZE);
+ gf128mul_lle((be128 *)dctx->shash, &ctx->key);
+ }
+}
+
+static inline void __ghash_blocks(struct p8_ghash_ctx *ctx,
+ struct p8_ghash_desc_ctx *dctx,
+ const u8 *src, unsigned int srclen)
+{
+ if (!IN_INTERRUPT) {
+ preempt_disable();
+ pagefault_disable();
+ enable_kernel_vsx();
+ gcm_ghash_p8(dctx->shash, ctx->htable,
+ src, srclen);
+ disable_kernel_vsx();
+ pagefault_enable();
+ preempt_enable();
+ } else {
+ while (srclen >= GHASH_BLOCK_SIZE) {
+ crypto_xor((u8 *)dctx->shash, src, GHASH_BLOCK_SIZE);
+ gf128mul_lle((be128 *)dctx->shash, &ctx->key);
+ srclen -= GHASH_BLOCK_SIZE;
+ src += GHASH_BLOCK_SIZE;
+ }
+ }
}

static int p8_ghash_update(struct shash_desc *desc,
@@ -131,49 +121,33 @@ static int p8_ghash_update(struct shash_
struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(desc->tfm));
struct p8_ghash_desc_ctx *dctx = shash_desc_ctx(desc);

- if (IN_INTERRUPT) {
- return crypto_shash_update(&dctx->fallback_desc, src,
- srclen);
- } else {
- if (dctx->bytes) {
- if (dctx->bytes + srclen < GHASH_DIGEST_SIZE) {
- memcpy(dctx->buffer + dctx->bytes, src,
- srclen);
- dctx->bytes += srclen;
- return 0;
- }
+ if (dctx->bytes) {
+ if (dctx->bytes + srclen < GHASH_DIGEST_SIZE) {
memcpy(dctx->buffer + dctx->bytes, src,
- GHASH_DIGEST_SIZE - dctx->bytes);
- preempt_disable();
- pagefault_disable();
- enable_kernel_vsx();
- gcm_ghash_p8(dctx->shash, ctx->htable,
- dctx->buffer, GHASH_DIGEST_SIZE);
- disable_kernel_vsx();
- pagefault_enable();
- preempt_enable();
- src += GHASH_DIGEST_SIZE - dctx->bytes;
- srclen -= GHASH_DIGEST_SIZE - dctx->bytes;
- dctx->bytes = 0;
+ srclen);
+ dctx->bytes += srclen;
+ return 0;
}
- len = srclen & ~(GHASH_DIGEST_SIZE - 1);
- if (len) {
- preempt_disable();
- pagefault_disable();
- enable_kernel_vsx();
- gcm_ghash_p8(dctx->shash, ctx->htable, src, len);
- disable_kernel_vsx();
- pagefault_enable();
- preempt_enable();
- src += len;
- srclen -= len;
- }
- if (srclen) {
- memcpy(dctx->buffer, src, srclen);
- dctx->bytes = srclen;
- }
- return 0;
+ memcpy(dctx->buffer + dctx->bytes, src,
+ GHASH_DIGEST_SIZE - dctx->bytes);
+
+ __ghash_block(ctx, dctx);
+
+ src += GHASH_DIGEST_SIZE - dctx->bytes;
+ srclen -= GHASH_DIGEST_SIZE - dctx->bytes;
+ dctx->bytes = 0;
+ }
+ len = srclen & ~(GHASH_DIGEST_SIZE - 1);
+ if (len) {
+ __ghash_blocks(ctx, dctx, src, len);
+ src += len;
+ srclen -= len;
}
+ if (srclen) {
+ memcpy(dctx->buffer, src, srclen);
+ dctx->bytes = srclen;
+ }
+ return 0;
}

static int p8_ghash_final(struct shash_desc *desc, u8 *out)
@@ -182,25 +156,14 @@ static int p8_ghash_final(struct shash_d
struct p8_ghash_ctx *ctx = crypto_tfm_ctx(crypto_shash_tfm(desc->tfm));
struct p8_ghash_desc_ctx *dctx = shash_desc_ctx(desc);

- if (IN_INTERRUPT) {
- return crypto_shash_final(&dctx->fallback_desc, out);
- } else {
- if (dctx->bytes) {
- for (i = dctx->bytes; i < GHASH_DIGEST_SIZE; i++)
- dctx->buffer[i] = 0;
- preempt_disable();
- pagefault_disable();
- enable_kernel_vsx();
- gcm_ghash_p8(dctx->shash, ctx->htable,
- dctx->buffer, GHASH_DIGEST_SIZE);
- disable_kernel_vsx();
- pagefault_enable();
- preempt_enable();
- dctx->bytes = 0;
- }
- memcpy(out, dctx->shash, GHASH_DIGEST_SIZE);
- return 0;
+ if (dctx->bytes) {
+ for (i = dctx->bytes; i < GHASH_DIGEST_SIZE; i++)
+ dctx->buffer[i] = 0;
+ __ghash_block(ctx, dctx);
+ dctx->bytes = 0;
}
+ memcpy(out, dctx->shash, GHASH_DIGEST_SIZE);
+ return 0;
}

struct shash_alg p8_ghash_alg = {
@@ -215,11 +178,8 @@ struct shash_alg p8_ghash_alg = {
.cra_name = "ghash",
.cra_driver_name = "p8_ghash",
.cra_priority = 1000,
- .cra_flags = CRYPTO_ALG_NEED_FALLBACK,
.cra_blocksize = GHASH_BLOCK_SIZE,
.cra_ctxsize = sizeof(struct p8_ghash_ctx),
.cra_module = THIS_MODULE,
- .cra_init = p8_ghash_init_tfm,
- .cra_exit = p8_ghash_exit_tfm,
},
};