[PATCH BACKPORT 4.19, 5.0, 5.1] crypto: vmx - ghash: do nosimd fallback manually

[PATCH BACKPORT 4.19, 5.0, 5.1] crypto: vmx - ghash: do nosimd fallback manually

[Daniel Axtens]

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>
(backported from commit 357d065a44cdd77ed5ff35155a989f2a763e96ef)
Signed-off-by: Daniel Axtens <dja@axtens.net>
---
 drivers/crypto/vmx/ghash.c | 212 +++++++++++++++----------------------
 1 file changed, 86 insertions(+), 126 deletions(-)

diff --git a/drivers/crypto/vmx/ghash.c b/drivers/crypto/vmx/ghash.c
index dd8b8716467a..2d1a8cd35509 100644
--- 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 htable[16],
 		  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_shash *tfm, const u8 *key,
 	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_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);
 
-	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;
-		}
-		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;
+				srclen);
+			dctx->bytes += srclen;
+			return 0;
 		}
-		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_desc *desc, u8 *out)
 	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,
 	},
 };
-- 
2.19.1

Re: [PATCH BACKPORT 4.19, 5.0, 5.1] crypto: vmx - ghash: do nosimd fallback manually

[Christophe Leroy]

Daniel Axtens <dja@axtens.net> a écrit :

Hi

I think you have to mention the upstream commit Id when submitting a  
patch to stable, see   
https://elixir.bootlin.com/linux/v5.2-rc1/source/Documentation/process/stable-kernel-rules.rst

Christophe

> 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>
> (backported from commit 357d065a44cdd77ed5ff35155a989f2a763e96ef)
> Signed-off-by: Daniel Axtens <dja@axtens.net>
> ---
>  drivers/crypto/vmx/ghash.c | 212 +++++++++++++++----------------------
>  1 file changed, 86 insertions(+), 126 deletions(-)
>
> diff --git a/drivers/crypto/vmx/ghash.c b/drivers/crypto/vmx/ghash.c
> index dd8b8716467a..2d1a8cd35509 100644
> --- 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 htable[16],
>  		  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_shash  
> *tfm, const u8 *key,
>  	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_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);
>
> -	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;
> -		}
> -		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;
> +				srclen);
> +			dctx->bytes += srclen;
> +			return 0;
>  		}
> -		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_desc  
> *desc, u8 *out)
>  	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,
>  	},
>  };
> --
> 2.19.1

Re: [PATCH BACKPORT 4.19, 5.0, 5.1] crypto: vmx - ghash: do nosimd fallback manually

[Daniel Axtens]

Christophe Leroy <christophe.leroy@c-s.fr> writes:

> Daniel Axtens <dja@axtens.net> a écrit :
>
> Hi
>
> I think you have to mention the upstream commit Id when submitting a  
> patch to stable, see   
> https://elixir.bootlin.com/linux/v5.2-rc1/source/Documentation/process/stable-kernel-rules.rst

Argh, right, sorry, still in Canonical Stable Release Update mode:
>> (backported from commit 357d065a44cdd77ed5ff35155a989f2a763e96ef)

I'll do a backport v2 with the correct format.

Regards,
Daniel

>
> Christophe
>
>> 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>
>> ---
>>  drivers/crypto/vmx/ghash.c | 212 +++++++++++++++----------------------
>>  1 file changed, 86 insertions(+), 126 deletions(-)
>>
>> diff --git a/drivers/crypto/vmx/ghash.c b/drivers/crypto/vmx/ghash.c
>> index dd8b8716467a..2d1a8cd35509 100644
>> --- 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 htable[16],
>>  		  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_shash  
>> *tfm, const u8 *key,
>>  	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_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);
>>
>> -	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;
>> -		}
>> -		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;
>> +				srclen);
>> +			dctx->bytes += srclen;
>> +			return 0;
>>  		}
>> -		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_desc  
>> *desc, u8 *out)
>>  	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,
>>  	},
>>  };
>> --
>> 2.19.1