text: /**
   * 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 <yoder1@us.ibm.com>
   */
  
  #include <crypto/internal/aead.h>
  #include <crypto/aes.h>
  #include <crypto/algapi.h>
  #include <crypto/gcm.h>
  #include <crypto/scatterwalk.h>
  #include <linux/module.h>
  #include <linux/types.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_aead_ctx(tfm);
  	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_aead_ctx(tfm);
  	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 gcm4106_aes_nx_setauthsize(struct crypto_aead *tfm,
  				      unsigned int authsize)
  {
  	switch (authsize) {
  	case 8:
  	case 12:
  	case 16:
  		break;
  	default:
  		return -EINVAL;
  	}
  
  	return 0;
  }
  
  static int nx_gca(struct nx_crypto_ctx  *nx_ctx,
  		  struct aead_request   *req,
  		  u8                    *out,
  		  unsigned int assoclen)
  {
  	int rc;
  	struct nx_csbcpb *csbcpb_aead = nx_ctx->csbcpb_aead;
  	struct scatter_walk walk;
  	struct nx_sg *nx_sg = nx_ctx->in_sg;
  	unsigned int nbytes = assoclen;
  	unsigned int processed = 0, to_process;
  	unsigned int max_sg_len;
  
  	if (nbytes <= AES_BLOCK_SIZE) {
  		scatterwalk_start(&walk, req->src);
  		scatterwalk_copychunks(out, &walk, nbytes, SCATTERWALK_FROM_SG);
  		scatterwalk_done(&walk, SCATTERWALK_FROM_SG, 0);
  		return 0;
  	}
  
  	NX_CPB_FDM(csbcpb_aead) &= ~NX_FDM_CONTINUATION;
  
  	/* page_limit: number of sg entries that fit on one page */
  	max_sg_len = min_t(u64, nx_driver.of.max_sg_len/sizeof(struct nx_sg),
  			   nx_ctx->ap->sglen);
  	max_sg_len = min_t(u64, max_sg_len,
  			   nx_ctx->ap->databytelen/NX_PAGE_SIZE);
  
  	do {
  		/*
  		 * to_process: the data chunk to process in this update.
  		 * This value is bound by sg list limits.
  		 */
  		to_process = min_t(u64, nbytes - processed,
  				   nx_ctx->ap->databytelen);
  		to_process = min_t(u64, to_process,
  				   NX_PAGE_SIZE * (max_sg_len - 1));
  
  		nx_sg = nx_walk_and_build(nx_ctx->in_sg, max_sg_len,
  					  req->src, processed, &to_process);
  
  		if ((to_process + processed) < nbytes)
  			NX_CPB_FDM(csbcpb_aead) |= NX_FDM_INTERMEDIATE;
  		else
  			NX_CPB_FDM(csbcpb_aead) &= ~NX_FDM_INTERMEDIATE;
  
  		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)
  			return rc;
  
  		memcpy(csbcpb_aead->cpb.aes_gca.in_pat,
  				csbcpb_aead->cpb.aes_gca.out_pat,
  				AES_BLOCK_SIZE);
  		NX_CPB_FDM(csbcpb_aead) |= NX_FDM_CONTINUATION;
  
  		atomic_inc(&(nx_ctx->stats->aes_ops));
  		atomic64_add(assoclen, &(nx_ctx->stats->aes_bytes));
  
  		processed += to_process;
  	} while (processed < nbytes);
  
  	memcpy(out, csbcpb_aead->cpb.aes_gca.out_pat, AES_BLOCK_SIZE);
  
  	return rc;
  }
  
  static int gmac(struct aead_request *req, struct blkcipher_desc *desc,
  		unsigned int assoclen)
  {
  	int rc;
  	struct nx_crypto_ctx *nx_ctx =
  		crypto_aead_ctx(crypto_aead_reqtfm(req));
  	struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;
  	struct nx_sg *nx_sg;
  	unsigned int nbytes = assoclen;
  	unsigned int processed = 0, to_process;
  	unsigned int max_sg_len;
  
  	/* Set GMAC mode */
  	csbcpb->cpb.hdr.mode = NX_MODE_AES_GMAC;
  
  	NX_CPB_FDM(csbcpb) &= ~NX_FDM_CONTINUATION;
  
  	/* page_limit: number of sg entries that fit on one page */
  	max_sg_len = min_t(u64, nx_driver.of.max_sg_len/sizeof(struct nx_sg),
  			   nx_ctx->ap->sglen);
  	max_sg_len = min_t(u64, max_sg_len,
  			   nx_ctx->ap->databytelen/NX_PAGE_SIZE);
  
  	/* Copy IV */
  	memcpy(csbcpb->cpb.aes_gcm.iv_or_cnt, desc->info, AES_BLOCK_SIZE);
  
  	do {
  		/*
  		 * to_process: the data chunk to process in this update.
  		 * This value is bound by sg list limits.
  		 */
  		to_process = min_t(u64, nbytes - processed,
  				   nx_ctx->ap->databytelen);
  		to_process = min_t(u64, to_process,
  				   NX_PAGE_SIZE * (max_sg_len - 1));
  
  		nx_sg = nx_walk_and_build(nx_ctx->in_sg, max_sg_len,
  					  req->src, processed, &to_process);
  
  		if ((to_process + processed) < nbytes)
  			NX_CPB_FDM(csbcpb) |= NX_FDM_INTERMEDIATE;
  		else
  			NX_CPB_FDM(csbcpb) &= ~NX_FDM_INTERMEDIATE;
  
  		nx_ctx->op.inlen = (nx_ctx->in_sg - nx_sg)
  					* sizeof(struct nx_sg);
  
  		csbcpb->cpb.aes_gcm.bit_length_data = 0;
  		csbcpb->cpb.aes_gcm.bit_length_aad = 8 * nbytes;
  
  		rc = nx_hcall_sync(nx_ctx, &nx_ctx->op,
  				req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP);
  		if (rc)
  			goto out;
  
  		memcpy(csbcpb->cpb.aes_gcm.in_pat_or_aad,
  			csbcpb->cpb.aes_gcm.out_pat_or_mac, AES_BLOCK_SIZE);
  		memcpy(csbcpb->cpb.aes_gcm.in_s0,
  			csbcpb->cpb.aes_gcm.out_s0, AES_BLOCK_SIZE);
  
  		NX_CPB_FDM(csbcpb) |= NX_FDM_CONTINUATION;
  
  		atomic_inc(&(nx_ctx->stats->aes_ops));
  		atomic64_add(assoclen, &(nx_ctx->stats->aes_bytes));
  
  		processed += to_process;
  	} while (processed < nbytes);
  
  out:
  	/* Restore GCM mode */
  	csbcpb->cpb.hdr.mode = NX_MODE_AES_GCM;
  	return rc;
  }
  
  static int gcm_empty(struct aead_request *req, struct blkcipher_desc *desc,
  		     int enc)
  {
  	int rc;
  	struct nx_crypto_ctx *nx_ctx =
  		crypto_aead_ctx(crypto_aead_reqtfm(req));
  	struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;
  	char out[AES_BLOCK_SIZE];
  	struct nx_sg *in_sg, *out_sg;
  	int len;
  
  	/* 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 */
  
  	/* Change to ECB mode */
  	csbcpb->cpb.hdr.mode = NX_MODE_AES_ECB;
  	memcpy(csbcpb->cpb.aes_ecb.key, csbcpb->cpb.aes_gcm.key,
  			sizeof(csbcpb->cpb.aes_ecb.key));
  	if (enc)
  		NX_CPB_FDM(csbcpb) |= NX_FDM_ENDE_ENCRYPT;
  	else
  		NX_CPB_FDM(csbcpb) &= ~NX_FDM_ENDE_ENCRYPT;
  
  	len = AES_BLOCK_SIZE;
  
  	/* Encrypt the counter/IV */
  	in_sg = nx_build_sg_list(nx_ctx->in_sg, (u8 *) desc->info,
  				 &len, nx_ctx->ap->sglen);
  
  	if (len != AES_BLOCK_SIZE)
  		return -EINVAL;
  
  	len = sizeof(out);
  	out_sg = nx_build_sg_list(nx_ctx->out_sg, (u8 *) out, &len,
  				  nx_ctx->ap->sglen);
  
  	if (len != sizeof(out))
  		return -EINVAL;
  
  	nx_ctx->op.inlen = (nx_ctx->in_sg - in_sg) * sizeof(struct nx_sg);
  	nx_ctx->op.outlen = (nx_ctx->out_sg - out_sg) * sizeof(struct nx_sg);
  
  	rc = nx_hcall_sync(nx_ctx, &nx_ctx->op,
  			   desc->flags & CRYPTO_TFM_REQ_MAY_SLEEP);
  	if (rc)
  		goto out;
  	atomic_inc(&(nx_ctx->stats->aes_ops));
  
  	/* Copy out the auth tag */
  	memcpy(csbcpb->cpb.aes_gcm.out_pat_or_mac, out,
  			crypto_aead_authsize(crypto_aead_reqtfm(req)));
  out:
  	/* Restore XCBC mode */
  	csbcpb->cpb.hdr.mode = NX_MODE_AES_GCM;
  
  	/*
  	 * ECB key uses the same region that GCM AAD and counter, so it's safe
  	 * to just fill it with zeroes.
  	 */
  	memset(csbcpb->cpb.aes_ecb.key, 0, sizeof(csbcpb->cpb.aes_ecb.key));
  
  	return rc;
  }
  
  static int gcm_aes_nx_crypt(struct aead_request *req, int enc,
  			    unsigned int assoclen)
  {
  	struct nx_crypto_ctx *nx_ctx =
  		crypto_aead_ctx(crypto_aead_reqtfm(req));
  	struct nx_gcm_rctx *rctx = aead_request_ctx(req);
  	struct nx_csbcpb *csbcpb = nx_ctx->csbcpb;
  	struct blkcipher_desc desc;
  	unsigned int nbytes = req->cryptlen;
  	unsigned int processed = 0, to_process;
  	unsigned long irq_flags;
  	int rc = -EINVAL;
  
  	spin_lock_irqsave(&nx_ctx->lock, irq_flags);
  
  	desc.info = rctx->iv;
  	/* initialize the counter */
  	*(u32 *)(desc.info + NX_GCM_CTR_OFFSET) = 1;
  
  	if (nbytes == 0) {
  		if (assoclen == 0)
  			rc = gcm_empty(req, &desc, enc);
  		else
  			rc = gmac(req, &desc, assoclen);
  		if (rc)
  			goto out;
  		else
  			goto mac;
  	}
  
  	/* Process associated data */
  	csbcpb->cpb.aes_gcm.bit_length_aad = assoclen * 8;
  	if (assoclen) {
  		rc = nx_gca(nx_ctx, req, csbcpb->cpb.aes_gcm.in_pat_or_aad,
  			    assoclen);
  		if (rc)
  			goto out;
  	}
  
  	/* Set flags for encryption */
  	NX_CPB_FDM(csbcpb) &= ~NX_FDM_CONTINUATION;
  	if (enc) {
  		NX_CPB_FDM(csbcpb) |= NX_FDM_ENDE_ENCRYPT;
  	} else {
  		NX_CPB_FDM(csbcpb) &= ~NX_FDM_ENDE_ENCRYPT;
  		nbytes -= crypto_aead_authsize(crypto_aead_reqtfm(req));
  	}
  
  	do {
  		to_process = nbytes - processed;
  
  		csbcpb->cpb.aes_gcm.bit_length_data = nbytes * 8;
  		rc = nx_build_sg_lists(nx_ctx, &desc, req->dst,
  				       req->src, &to_process,
  				       processed + req->assoclen,
  				       csbcpb->cpb.aes_gcm.iv_or_cnt);
  
  		if (rc)
  			goto out;
  
  		if ((to_process + processed) < nbytes)
  			NX_CPB_FDM(csbcpb) |= NX_FDM_INTERMEDIATE;
  		else
  			NX_CPB_FDM(csbcpb) &= ~NX_FDM_INTERMEDIATE;
  
  
  		rc = nx_hcall_sync(nx_ctx, &nx_ctx->op,
  				   req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP);
  		if (rc)
  			goto out;
  
  		memcpy(desc.info, csbcpb->cpb.aes_gcm.out_cnt, AES_BLOCK_SIZE);
  		memcpy(csbcpb->cpb.aes_gcm.in_pat_or_aad,
  			csbcpb->cpb.aes_gcm.out_pat_or_mac, AES_BLOCK_SIZE);
  		memcpy(csbcpb->cpb.aes_gcm.in_s0,
  			csbcpb->cpb.aes_gcm.out_s0, AES_BLOCK_SIZE);
  
  		NX_CPB_FDM(csbcpb) |= NX_FDM_CONTINUATION;
  
  		atomic_inc(&(nx_ctx->stats->aes_ops));
  		atomic64_add(csbcpb->csb.processed_byte_count,
  			     &(nx_ctx->stats->aes_bytes));
  
  		processed += to_process;
  	} while (processed < nbytes);
  
  mac:
  	if (enc) {
  		/* copy out the auth tag */
  		scatterwalk_map_and_copy(
  			csbcpb->cpb.aes_gcm.out_pat_or_mac,
  			req->dst, req->assoclen + nbytes,
  			crypto_aead_authsize(crypto_aead_reqtfm(req)),
  			SCATTERWALK_TO_SG);
  	} else {
  		u8 *itag = nx_ctx->priv.gcm.iauth_tag;
  		u8 *otag = csbcpb->cpb.aes_gcm.out_pat_or_mac;
  
  		scatterwalk_map_and_copy(
  			itag, req->src, req->assoclen + nbytes,
  			crypto_aead_authsize(crypto_aead_reqtfm(req)),
  			SCATTERWALK_FROM_SG);
  		rc = crypto_memneq(itag, otag,
  			    crypto_aead_authsize(crypto_aead_reqtfm(req))) ?
  		     -EBADMSG : 0;
  	}
  out:
  	spin_unlock_irqrestore(&nx_ctx->lock, irq_flags);
  	return rc;
  }
  
  static int gcm_aes_nx_encrypt(struct aead_request *req)
  {
  	struct nx_gcm_rctx *rctx = aead_request_ctx(req);
  	char *iv = rctx->iv;
  
  	memcpy(iv, req->iv, GCM_AES_IV_SIZE);
  
  	return gcm_aes_nx_crypt(req, 1, req->assoclen);
  }
  
  static int gcm_aes_nx_decrypt(struct aead_request *req)
  {
  	struct nx_gcm_rctx *rctx = aead_request_ctx(req);
  	char *iv = rctx->iv;
  
  	memcpy(iv, req->iv, GCM_AES_IV_SIZE);
  
  	return gcm_aes_nx_crypt(req, 0, req->assoclen);
  }
  
  static int gcm4106_aes_nx_encrypt(struct aead_request *req)
  {
  	struct nx_crypto_ctx *nx_ctx =
  		crypto_aead_ctx(crypto_aead_reqtfm(req));
  	struct nx_gcm_rctx *rctx = aead_request_ctx(req);
  	char *iv = rctx->iv;
  	char *nonce = nx_ctx->priv.gcm.nonce;
  
  	memcpy(iv, nonce, NX_GCM4106_NONCE_LEN);
  	memcpy(iv + NX_GCM4106_NONCE_LEN, req->iv, 8);
  
  	if (req->assoclen < 8)
  		return -EINVAL;
  
  	return gcm_aes_nx_crypt(req, 1, req->assoclen - 8);
  }
  
  static int gcm4106_aes_nx_decrypt(struct aead_request *req)
  {
  	struct nx_crypto_ctx *nx_ctx =
  		crypto_aead_ctx(crypto_aead_reqtfm(req));
  	struct nx_gcm_rctx *rctx = aead_request_ctx(req);
  	char *iv = rctx->iv;
  	char *nonce = nx_ctx->priv.gcm.nonce;
  
  	memcpy(iv, nonce, NX_GCM4106_NONCE_LEN);
  	memcpy(iv + NX_GCM4106_NONCE_LEN, req->iv, 8);
  
  	if (req->assoclen < 8)
  		return -EINVAL;
  
  	return gcm_aes_nx_crypt(req, 0, req->assoclen - 8);
  }
  
  /* 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 aead_alg nx_gcm_aes_alg = {
  	.base = {
  		.cra_name        = "gcm(aes)",
  		.cra_driver_name = "gcm-aes-nx",
  		.cra_priority    = 300,
  		.cra_blocksize   = 1,
  		.cra_ctxsize     = sizeof(struct nx_crypto_ctx),
  		.cra_module      = THIS_MODULE,
  	},
  	.init        = nx_crypto_ctx_aes_gcm_init,
  	.exit        = nx_crypto_ctx_aead_exit,
  	.ivsize      = GCM_AES_IV_SIZE,
  	.maxauthsize = AES_BLOCK_SIZE,
  	.setkey      = gcm_aes_nx_set_key,
  	.encrypt     = gcm_aes_nx_encrypt,
  	.decrypt     = gcm_aes_nx_decrypt,
  };
  
  struct aead_alg nx_gcm4106_aes_alg = {
  	.base = {
  		.cra_name        = "rfc4106(gcm(aes))",
  		.cra_driver_name = "rfc4106-gcm-aes-nx",
  		.cra_priority    = 300,
  		.cra_blocksize   = 1,
  		.cra_ctxsize     = sizeof(struct nx_crypto_ctx),
  		.cra_module      = THIS_MODULE,
  	},
  	.init        = nx_crypto_ctx_aes_gcm_init,
  	.exit        = nx_crypto_ctx_aead_exit,
  	.ivsize      = GCM_RFC4106_IV_SIZE,
  	.maxauthsize = AES_BLOCK_SIZE,
  	.setkey      = gcm4106_aes_nx_set_key,
  	.setauthsize = gcm4106_aes_nx_setauthsize,
  	.encrypt     = gcm4106_aes_nx_encrypt,
  	.decrypt     = gcm4106_aes_nx_decrypt,
  };
  