drivers/crypto/nx/nx-aes-gcm.c - kernel/common - Git at Google

 /**
  * AES GCM routines supporting the Power 7+ Nest Accelerators driver
  *
  * Copyright (C) 2012 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.
  *
  * Author: Kent Yoder <[email protected]>
  */

 #include <crypto/internal/aead.h>
 #include <crypto/aes.h>
 #include <crypto/algapi.h>
 #include <crypto/scatterwalk.h>
 #include <linux/module.h>
 #include <linux/types.h>
 #include <linux/crypto.h>
 #include <asm/vio.h>

 #include "nx_csbcpb.h"
 #include "nx.h"


 static int gcm_aes_nx_set_key(struct crypto_aead *tfm,
 			      const u8           *in_key,
 			      unsigned int        key_len)
 {
 	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(&tfm->base);
 	struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;
 	struct nx_csbcpb *csbcpb_aead = nx_ctx->csbcpb_aead;

 	nx_ctx_init(nx_ctx, HCOP_FC_AES);

 	switch (key_len) {
 	case AES_KEYSIZE_128:
 		NX_CPB_SET_KEY_SIZE(csbcpb, NX_KS_AES_128);
 		NX_CPB_SET_KEY_SIZE(csbcpb_aead, NX_KS_AES_128);
 		nx_ctx->ap = &nx_ctx->props[NX_PROPS_AES_128];
 		break;
 	case AES_KEYSIZE_192:
 		NX_CPB_SET_KEY_SIZE(csbcpb, NX_KS_AES_192);
 		NX_CPB_SET_KEY_SIZE(csbcpb_aead, NX_KS_AES_192);
 		nx_ctx->ap = &nx_ctx->props[NX_PROPS_AES_192];
 		break;
 	case AES_KEYSIZE_256:
 		NX_CPB_SET_KEY_SIZE(csbcpb, NX_KS_AES_256);
 		NX_CPB_SET_KEY_SIZE(csbcpb_aead, NX_KS_AES_256);
 		nx_ctx->ap = &nx_ctx->props[NX_PROPS_AES_256];
 		break;
 	default:
 		return -EINVAL;
 	}

 	csbcpb->cpb.hdr.mode = NX_MODE_AES_GCM;
 	memcpy(csbcpb->cpb.aes_gcm.key, in_key, key_len);

 	csbcpb_aead->cpb.hdr.mode = NX_MODE_AES_GCA;
 	memcpy(csbcpb_aead->cpb.aes_gca.key, in_key, key_len);

 	return 0;
 }

 static int gcm4106_aes_nx_set_key(struct crypto_aead *tfm,
 				  const u8           *in_key,
 				  unsigned int        key_len)
 {
 	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(&tfm->base);
 	char *nonce = nx_ctx->priv.gcm.nonce;
 	int rc;

 	if (key_len < 4)
 		return -EINVAL;

 	key_len -= 4;

 	rc = gcm_aes_nx_set_key(tfm, in_key, key_len);
 	if (rc)
 		goto out;

 	memcpy(nonce, in_key + key_len, 4);
 out:
 	return rc;
 }

 static int gcm_aes_nx_setauthsize(struct crypto_aead *tfm,
 				  unsigned int authsize)
 {
 	if (authsize > crypto_aead_alg(tfm)->maxauthsize)
 		return -EINVAL;

 	crypto_aead_crt(tfm)->authsize = authsize;

 	return 0;
 }

 static int gcm4106_aes_nx_setauthsize(struct crypto_aead *tfm,
 				      unsigned int authsize)
 {
 	switch (authsize) {
 	case 8:
 	case 12:
 	case 16:
 		break;
 	default:
 		return -EINVAL;
 	}

 	crypto_aead_crt(tfm)->authsize = authsize;

 	return 0;
 }

 static int nx_gca(struct nx_crypto_ctx  *nx_ctx,
 		  struct aead_request   *req,
 		  u8                    *out)
 {
 	struct nx_csbcpb *csbcpb_aead = nx_ctx->csbcpb_aead;
 	int rc = -EINVAL;
 	struct scatter_walk walk;
 	struct nx_sg *nx_sg = nx_ctx->in_sg;

 	if (req->assoclen > nx_ctx->ap->databytelen)
 		goto out;

 	if (req->assoclen <= AES_BLOCK_SIZE) {
 		scatterwalk_start(&walk, req->assoc);
 		scatterwalk_copychunks(out, &walk, req->assoclen,
 				       SCATTERWALK_FROM_SG);
 		scatterwalk_done(&walk, SCATTERWALK_FROM_SG, 0);

 		rc = 0;
 		goto out;
 	}

 	nx_sg = nx_walk_and_build(nx_sg, nx_ctx->ap->sglen, req->assoc, 0,
 				  req->assoclen);
 	nx_ctx->op_aead.inlen = (nx_ctx->in_sg - nx_sg) * sizeof(struct nx_sg);

 	rc = nx_hcall_sync(nx_ctx, &nx_ctx->op_aead,
 			   req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP);
 	if (rc)
 		goto out;

 	atomic_inc(&(nx_ctx->stats->aes_ops));
 	atomic64_add(req->assoclen, &(nx_ctx->stats->aes_bytes));

 	memcpy(out, csbcpb_aead->cpb.aes_gca.out_pat, AES_BLOCK_SIZE);
 out:
 	return rc;
 }

 static int gcm_aes_nx_crypt(struct aead_request *req, int enc)
 {
 	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
 	struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;
 	struct blkcipher_desc desc;
 	unsigned int nbytes = req->cryptlen;
 	int rc = -EINVAL;

 	if (nbytes > nx_ctx->ap->databytelen)
 		goto out;

 	desc.info = nx_ctx->priv.gcm.iv;
 	/* initialize the counter */
 	*(u32 *)(desc.info + NX_GCM_CTR_OFFSET) = 1;

 	/* For scenarios where the input message is zero length, AES CTR mode
 	 * may be used. Set the source data to be a single block (16B) of all
 	 * zeros, and set the input IV value to be the same as the GMAC IV
 	 * value. - nx_wb 4.8.1.3 */
 	if (nbytes == 0) {
 		char src[AES_BLOCK_SIZE] = {};
 		struct scatterlist sg;

 		desc.tfm = crypto_alloc_blkcipher("ctr(aes)", 0, 0);
 		if (IS_ERR(desc.tfm)) {
 			rc = -ENOMEM;
 			goto out;
 		}

 		crypto_blkcipher_setkey(desc.tfm, csbcpb->cpb.aes_gcm.key,
 			NX_CPB_KEY_SIZE(csbcpb) == NX_KS_AES_128 ? 16 :
 			NX_CPB_KEY_SIZE(csbcpb) == NX_KS_AES_192 ? 24 : 32);

 		sg_init_one(&sg, src, AES_BLOCK_SIZE);
 		if (enc)
 			crypto_blkcipher_encrypt_iv(&desc, req->dst, &sg,
 						    AES_BLOCK_SIZE);
 		else
 			crypto_blkcipher_decrypt_iv(&desc, req->dst, &sg,
 						    AES_BLOCK_SIZE);
 		crypto_free_blkcipher(desc.tfm);

 		rc = 0;
 		goto out;
 	}

 	desc.tfm = (struct crypto_blkcipher *)req->base.tfm;

 	csbcpb->cpb.aes_gcm.bit_length_aad = req->assoclen * 8;

 	if (req->assoclen) {
 		rc = nx_gca(nx_ctx, req, csbcpb->cpb.aes_gcm.in_pat_or_aad);
 		if (rc)
 			goto out;
 	}

 	if (enc)
 		NX_CPB_FDM(csbcpb) |= NX_FDM_ENDE_ENCRYPT;
 	else
 		nbytes -= AES_BLOCK_SIZE;

 	csbcpb->cpb.aes_gcm.bit_length_data = nbytes * 8;

 	rc = nx_build_sg_lists(nx_ctx, &desc, req->dst, req->src, nbytes,
 			       csbcpb->cpb.aes_gcm.iv_or_cnt);
 	if (rc)
 		goto out;

 	rc = nx_hcall_sync(nx_ctx, &nx_ctx->op,
 			   req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP);
 	if (rc)
 		goto out;

 	atomic_inc(&(nx_ctx->stats->aes_ops));
 	atomic64_add(csbcpb->csb.processed_byte_count,
 		     &(nx_ctx->stats->aes_bytes));

 	if (enc) {
 		/* copy out the auth tag */
 		scatterwalk_map_and_copy(csbcpb->cpb.aes_gcm.out_pat_or_mac,
 				 req->dst, nbytes,
 				 crypto_aead_authsize(crypto_aead_reqtfm(req)),
 				 SCATTERWALK_TO_SG);
 	} else if (req->assoclen) {
 		u8 *itag = nx_ctx->priv.gcm.iauth_tag;
 		u8 *otag = csbcpb->cpb.aes_gcm.out_pat_or_mac;

 		scatterwalk_map_and_copy(itag, req->dst, nbytes,
 				 crypto_aead_authsize(crypto_aead_reqtfm(req)),
 				 SCATTERWALK_FROM_SG);
 		rc = memcmp(itag, otag,
 			    crypto_aead_authsize(crypto_aead_reqtfm(req))) ?
 		     -EBADMSG : 0;
 	}
 out:
 	return rc;
 }

 static int gcm_aes_nx_encrypt(struct aead_request *req)
 {
 	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
 	char *iv = nx_ctx->priv.gcm.iv;

 	memcpy(iv, req->iv, 12);

 	return gcm_aes_nx_crypt(req, 1);
 }

 static int gcm_aes_nx_decrypt(struct aead_request *req)
 {
 	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
 	char *iv = nx_ctx->priv.gcm.iv;

 	memcpy(iv, req->iv, 12);

 	return gcm_aes_nx_crypt(req, 0);
 }

 static int gcm4106_aes_nx_encrypt(struct aead_request *req)
 {
 	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
 	char *iv = nx_ctx->priv.gcm.iv;
 	char *nonce = nx_ctx->priv.gcm.nonce;

 	memcpy(iv, nonce, NX_GCM4106_NONCE_LEN);
 	memcpy(iv + NX_GCM4106_NONCE_LEN, req->iv, 8);

 	return gcm_aes_nx_crypt(req, 1);
 }

 static int gcm4106_aes_nx_decrypt(struct aead_request *req)
 {
 	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
 	char *iv = nx_ctx->priv.gcm.iv;
 	char *nonce = nx_ctx->priv.gcm.nonce;

 	memcpy(iv, nonce, NX_GCM4106_NONCE_LEN);
 	memcpy(iv + NX_GCM4106_NONCE_LEN, req->iv, 8);

 	return gcm_aes_nx_crypt(req, 0);
 }

 /* tell the block cipher walk routines that this is a stream cipher by
  * setting cra_blocksize to 1. Even using blkcipher_walk_virt_block
  * during encrypt/decrypt doesn't solve this problem, because it calls
  * blkcipher_walk_done under the covers, which doesn't use walk->blocksize,
  * but instead uses this tfm->blocksize. */
 struct crypto_alg nx_gcm_aes_alg = {
 	.cra_name        = "gcm(aes)",
 	.cra_driver_name = "gcm-aes-nx",
 	.cra_priority    = 300,
 	.cra_flags       = CRYPTO_ALG_TYPE_AEAD,
 	.cra_blocksize   = 1,
 	.cra_ctxsize     = sizeof(struct nx_crypto_ctx),
 	.cra_type        = &crypto_aead_type,
 	.cra_module      = THIS_MODULE,
 	.cra_init        = nx_crypto_ctx_aes_gcm_init,
 	.cra_exit        = nx_crypto_ctx_exit,
 	.cra_aead = {
 		.ivsize      = AES_BLOCK_SIZE,
 		.maxauthsize = AES_BLOCK_SIZE,
 		.setkey      = gcm_aes_nx_set_key,
 		.setauthsize = gcm_aes_nx_setauthsize,
 		.encrypt     = gcm_aes_nx_encrypt,
 		.decrypt     = gcm_aes_nx_decrypt,
 	}
 };

 struct crypto_alg nx_gcm4106_aes_alg = {
 	.cra_name        = "rfc4106(gcm(aes))",
 	.cra_driver_name = "rfc4106-gcm-aes-nx",
 	.cra_priority    = 300,
 	.cra_flags       = CRYPTO_ALG_TYPE_AEAD,
 	.cra_blocksize   = 1,
 	.cra_ctxsize     = sizeof(struct nx_crypto_ctx),
 	.cra_type        = &crypto_nivaead_type,
 	.cra_module      = THIS_MODULE,
 	.cra_init        = nx_crypto_ctx_aes_gcm_init,
 	.cra_exit        = nx_crypto_ctx_exit,
 	.cra_aead = {
 		.ivsize      = 8,
 		.maxauthsize = AES_BLOCK_SIZE,
 		.geniv       = "seqiv",
 		.setkey      = gcm4106_aes_nx_set_key,
 		.setauthsize = gcm4106_aes_nx_setauthsize,
 		.encrypt     = gcm4106_aes_nx_encrypt,
 		.decrypt     = gcm4106_aes_nx_decrypt,
 	}
 };
	/**
	* AES GCM routines supporting the Power 7+ Nest Accelerators driver
	*
	* Copyright (C) 2012 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.
	*
	* Author: Kent Yoder <[email protected]>
	*/

	#include <crypto/internal/aead.h>
	#include <crypto/aes.h>
	#include <crypto/algapi.h>
	#include <crypto/scatterwalk.h>
	#include <linux/module.h>
	#include <linux/types.h>
	#include <linux/crypto.h>
	#include <asm/vio.h>

	#include "nx_csbcpb.h"
	#include "nx.h"


	static int gcm_aes_nx_set_key(struct crypto_aead *tfm,
	const u8 *in_key,
	unsigned int key_len)
	{
	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(&tfm->base);
	struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;
	struct nx_csbcpb *csbcpb_aead = nx_ctx->csbcpb_aead;

	nx_ctx_init(nx_ctx, HCOP_FC_AES);

	switch (key_len) {
	case AES_KEYSIZE_128:
	NX_CPB_SET_KEY_SIZE(csbcpb, NX_KS_AES_128);
	NX_CPB_SET_KEY_SIZE(csbcpb_aead, NX_KS_AES_128);
	nx_ctx->ap = &nx_ctx->props[NX_PROPS_AES_128];
	break;
	case AES_KEYSIZE_192:
	NX_CPB_SET_KEY_SIZE(csbcpb, NX_KS_AES_192);
	NX_CPB_SET_KEY_SIZE(csbcpb_aead, NX_KS_AES_192);
	nx_ctx->ap = &nx_ctx->props[NX_PROPS_AES_192];
	break;
	case AES_KEYSIZE_256:
	NX_CPB_SET_KEY_SIZE(csbcpb, NX_KS_AES_256);
	NX_CPB_SET_KEY_SIZE(csbcpb_aead, NX_KS_AES_256);
	nx_ctx->ap = &nx_ctx->props[NX_PROPS_AES_256];
	break;
	default:
	return -EINVAL;
	}

	csbcpb->cpb.hdr.mode = NX_MODE_AES_GCM;
	memcpy(csbcpb->cpb.aes_gcm.key, in_key, key_len);

	csbcpb_aead->cpb.hdr.mode = NX_MODE_AES_GCA;
	memcpy(csbcpb_aead->cpb.aes_gca.key, in_key, key_len);

	return 0;
	}

	static int gcm4106_aes_nx_set_key(struct crypto_aead *tfm,
	const u8 *in_key,
	unsigned int key_len)
	{
	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(&tfm->base);
	char *nonce = nx_ctx->priv.gcm.nonce;
	int rc;

	if (key_len < 4)
	return -EINVAL;

	key_len -= 4;

	rc = gcm_aes_nx_set_key(tfm, in_key, key_len);
	if (rc)
	goto out;

	memcpy(nonce, in_key + key_len, 4);
	out:
	return rc;
	}

	static int gcm_aes_nx_setauthsize(struct crypto_aead *tfm,
	unsigned int authsize)
	{
	if (authsize > crypto_aead_alg(tfm)->maxauthsize)
	return -EINVAL;

	crypto_aead_crt(tfm)->authsize = authsize;

	return 0;
	}

	static int gcm4106_aes_nx_setauthsize(struct crypto_aead *tfm,
	unsigned int authsize)
	{
	switch (authsize) {
	case 8:
	case 12:
	case 16:
	break;
	default:
	return -EINVAL;
	}

	crypto_aead_crt(tfm)->authsize = authsize;

	return 0;
	}

	static int nx_gca(struct nx_crypto_ctx *nx_ctx,
	struct aead_request *req,
	u8 *out)
	{
	struct nx_csbcpb *csbcpb_aead = nx_ctx->csbcpb_aead;
	int rc = -EINVAL;
	struct scatter_walk walk;
	struct nx_sg *nx_sg = nx_ctx->in_sg;

	if (req->assoclen > nx_ctx->ap->databytelen)
	goto out;

	if (req->assoclen <= AES_BLOCK_SIZE) {
	scatterwalk_start(&walk, req->assoc);
	scatterwalk_copychunks(out, &walk, req->assoclen,
	SCATTERWALK_FROM_SG);
	scatterwalk_done(&walk, SCATTERWALK_FROM_SG, 0);

	rc = 0;
	goto out;
	}

	nx_sg = nx_walk_and_build(nx_sg, nx_ctx->ap->sglen, req->assoc, 0,
	req->assoclen);
	nx_ctx->op_aead.inlen = (nx_ctx->in_sg - nx_sg) * sizeof(struct nx_sg);

	rc = nx_hcall_sync(nx_ctx, &nx_ctx->op_aead,
	req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP);
	if (rc)
	goto out;

	atomic_inc(&(nx_ctx->stats->aes_ops));
	atomic64_add(req->assoclen, &(nx_ctx->stats->aes_bytes));

	memcpy(out, csbcpb_aead->cpb.aes_gca.out_pat, AES_BLOCK_SIZE);
	out:
	return rc;
	}

	static int gcm_aes_nx_crypt(struct aead_request *req, int enc)
	{
	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
	struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;
	struct blkcipher_desc desc;
	unsigned int nbytes = req->cryptlen;
	int rc = -EINVAL;

	if (nbytes > nx_ctx->ap->databytelen)
	goto out;

	desc.info = nx_ctx->priv.gcm.iv;
	/* initialize the counter */
	(u32 )(desc.info + NX_GCM_CTR_OFFSET) = 1;

	/* For scenarios where the input message is zero length, AES CTR mode
	* may be used. Set the source data to be a single block (16B) of all
	* zeros, and set the input IV value to be the same as the GMAC IV
	* value. - nx_wb 4.8.1.3 */
	if (nbytes == 0) {
	char src[AES_BLOCK_SIZE] = {};
	struct scatterlist sg;

	desc.tfm = crypto_alloc_blkcipher("ctr(aes)", 0, 0);
	if (IS_ERR(desc.tfm)) {
	rc = -ENOMEM;
	goto out;
	}

	crypto_blkcipher_setkey(desc.tfm, csbcpb->cpb.aes_gcm.key,
	NX_CPB_KEY_SIZE(csbcpb) == NX_KS_AES_128 ? 16 :
	NX_CPB_KEY_SIZE(csbcpb) == NX_KS_AES_192 ? 24 : 32);

	sg_init_one(&sg, src, AES_BLOCK_SIZE);
	if (enc)
	crypto_blkcipher_encrypt_iv(&desc, req->dst, &sg,
	AES_BLOCK_SIZE);
	else
	crypto_blkcipher_decrypt_iv(&desc, req->dst, &sg,
	AES_BLOCK_SIZE);
	crypto_free_blkcipher(desc.tfm);

	rc = 0;
	goto out;
	}

	desc.tfm = (struct crypto_blkcipher *)req->base.tfm;

	csbcpb->cpb.aes_gcm.bit_length_aad = req->assoclen * 8;

	if (req->assoclen) {
	rc = nx_gca(nx_ctx, req, csbcpb->cpb.aes_gcm.in_pat_or_aad);
	if (rc)
	goto out;
	}

	if (enc)
	NX_CPB_FDM(csbcpb) \|= NX_FDM_ENDE_ENCRYPT;
	else
	nbytes -= AES_BLOCK_SIZE;

	csbcpb->cpb.aes_gcm.bit_length_data = nbytes * 8;

	rc = nx_build_sg_lists(nx_ctx, &desc, req->dst, req->src, nbytes,
	csbcpb->cpb.aes_gcm.iv_or_cnt);
	if (rc)
	goto out;

	rc = nx_hcall_sync(nx_ctx, &nx_ctx->op,
	req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP);
	if (rc)
	goto out;

	atomic_inc(&(nx_ctx->stats->aes_ops));
	atomic64_add(csbcpb->csb.processed_byte_count,
	&(nx_ctx->stats->aes_bytes));

	if (enc) {
	/* copy out the auth tag */
	scatterwalk_map_and_copy(csbcpb->cpb.aes_gcm.out_pat_or_mac,
	req->dst, nbytes,
	crypto_aead_authsize(crypto_aead_reqtfm(req)),
	SCATTERWALK_TO_SG);
	} else if (req->assoclen) {
	u8 *itag = nx_ctx->priv.gcm.iauth_tag;
	u8 *otag = csbcpb->cpb.aes_gcm.out_pat_or_mac;

	scatterwalk_map_and_copy(itag, req->dst, nbytes,
	crypto_aead_authsize(crypto_aead_reqtfm(req)),
	SCATTERWALK_FROM_SG);
	rc = memcmp(itag, otag,
	crypto_aead_authsize(crypto_aead_reqtfm(req))) ?
	-EBADMSG : 0;
	}
	out:
	return rc;
	}

	static int gcm_aes_nx_encrypt(struct aead_request *req)
	{
	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
	char *iv = nx_ctx->priv.gcm.iv;

	memcpy(iv, req->iv, 12);

	return gcm_aes_nx_crypt(req, 1);
	}

	static int gcm_aes_nx_decrypt(struct aead_request *req)
	{
	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
	char *iv = nx_ctx->priv.gcm.iv;

	memcpy(iv, req->iv, 12);

	return gcm_aes_nx_crypt(req, 0);
	}

	static int gcm4106_aes_nx_encrypt(struct aead_request *req)
	{
	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
	char *iv = nx_ctx->priv.gcm.iv;
	char *nonce = nx_ctx->priv.gcm.nonce;

	memcpy(iv, nonce, NX_GCM4106_NONCE_LEN);
	memcpy(iv + NX_GCM4106_NONCE_LEN, req->iv, 8);

	return gcm_aes_nx_crypt(req, 1);
	}

	static int gcm4106_aes_nx_decrypt(struct aead_request *req)
	{
	struct nx_crypto_ctx *nx_ctx = crypto_tfm_ctx(req->base.tfm);
	char *iv = nx_ctx->priv.gcm.iv;
	char *nonce = nx_ctx->priv.gcm.nonce;

	memcpy(iv, nonce, NX_GCM4106_NONCE_LEN);
	memcpy(iv + NX_GCM4106_NONCE_LEN, req->iv, 8);

	return gcm_aes_nx_crypt(req, 0);
	}

	/* tell the block cipher walk routines that this is a stream cipher by
	* setting cra_blocksize to 1. Even using blkcipher_walk_virt_block
	* during encrypt/decrypt doesn't solve this problem, because it calls
	* blkcipher_walk_done under the covers, which doesn't use walk->blocksize,
	* but instead uses this tfm->blocksize. */
	struct crypto_alg nx_gcm_aes_alg = {
	.cra_name = "gcm(aes)",
	.cra_driver_name = "gcm-aes-nx",
	.cra_priority = 300,
	.cra_flags = CRYPTO_ALG_TYPE_AEAD,
	.cra_blocksize = 1,
	.cra_ctxsize = sizeof(struct nx_crypto_ctx),
	.cra_type = &crypto_aead_type,
	.cra_module = THIS_MODULE,
	.cra_init = nx_crypto_ctx_aes_gcm_init,
	.cra_exit = nx_crypto_ctx_exit,
	.cra_aead = {
	.ivsize = AES_BLOCK_SIZE,
	.maxauthsize = AES_BLOCK_SIZE,
	.setkey = gcm_aes_nx_set_key,
	.setauthsize = gcm_aes_nx_setauthsize,
	.encrypt = gcm_aes_nx_encrypt,
	.decrypt = gcm_aes_nx_decrypt,
	}
	};

	struct crypto_alg nx_gcm4106_aes_alg = {
	.cra_name = "rfc4106(gcm(aes))",
	.cra_driver_name = "rfc4106-gcm-aes-nx",
	.cra_priority = 300,
	.cra_flags = CRYPTO_ALG_TYPE_AEAD,
	.cra_blocksize = 1,
	.cra_ctxsize = sizeof(struct nx_crypto_ctx),
	.cra_type = &crypto_nivaead_type,
	.cra_module = THIS_MODULE,
	.cra_init = nx_crypto_ctx_aes_gcm_init,
	.cra_exit = nx_crypto_ctx_exit,
	.cra_aead = {
	.ivsize = 8,
	.maxauthsize = AES_BLOCK_SIZE,
	.geniv = "seqiv",
	.setkey = gcm4106_aes_nx_set_key,
	.setauthsize = gcm4106_aes_nx_setauthsize,
	.encrypt = gcm4106_aes_nx_encrypt,
	.decrypt = gcm4106_aes_nx_decrypt,
	}
	};