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kernel/linux-rt-4.4.41/drivers/crypto/vmx/aes_ctr.c 4.94 KB
5113f6f70   김현기   kernel add
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  /**
   * AES CTR 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.
   *
   * Author: Marcelo Henrique Cerri <mhcerri@br.ibm.com>
   */
  
  #include <linux/types.h>
  #include <linux/err.h>
  #include <linux/crypto.h>
  #include <linux/delay.h>
  #include <linux/hardirq.h>
  #include <asm/switch_to.h>
  #include <crypto/aes.h>
  #include <crypto/scatterwalk.h>
  #include "aesp8-ppc.h"
  
  struct p8_aes_ctr_ctx {
  	struct crypto_blkcipher *fallback;
  	struct aes_key enc_key;
  };
  
  static int p8_aes_ctr_init(struct crypto_tfm *tfm)
  {
  	const char *alg;
  	struct crypto_blkcipher *fallback;
  	struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
  
  	if (!(alg = crypto_tfm_alg_name(tfm))) {
  		printk(KERN_ERR "Failed to get algorithm name.
  ");
  		return -ENOENT;
  	}
  
  	fallback =
  	    crypto_alloc_blkcipher(alg, 0, CRYPTO_ALG_NEED_FALLBACK);
  	if (IS_ERR(fallback)) {
  		printk(KERN_ERR
  		       "Failed to allocate transformation for '%s': %ld
  ",
  		       alg, PTR_ERR(fallback));
  		return PTR_ERR(fallback);
  	}
  	printk(KERN_INFO "Using '%s' as fallback implementation.
  ",
  	       crypto_tfm_alg_driver_name((struct crypto_tfm *) fallback));
  
  	crypto_blkcipher_set_flags(
  		fallback,
  		crypto_blkcipher_get_flags((struct crypto_blkcipher *)tfm));
  	ctx->fallback = fallback;
  
  	return 0;
  }
  
  static void p8_aes_ctr_exit(struct crypto_tfm *tfm)
  {
  	struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
  
  	if (ctx->fallback) {
  		crypto_free_blkcipher(ctx->fallback);
  		ctx->fallback = NULL;
  	}
  }
  
  static int p8_aes_ctr_setkey(struct crypto_tfm *tfm, const u8 *key,
  			     unsigned int keylen)
  {
  	int ret;
  	struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
  
  	pagefault_disable();
  	enable_kernel_altivec();
  	enable_kernel_vsx();
  	ret = aes_p8_set_encrypt_key(key, keylen * 8, &ctx->enc_key);
  	pagefault_enable();
  
  	ret += crypto_blkcipher_setkey(ctx->fallback, key, keylen);
  	return ret;
  }
  
  static void p8_aes_ctr_final(struct p8_aes_ctr_ctx *ctx,
  			     struct blkcipher_walk *walk)
  {
  	u8 *ctrblk = walk->iv;
  	u8 keystream[AES_BLOCK_SIZE];
  	u8 *src = walk->src.virt.addr;
  	u8 *dst = walk->dst.virt.addr;
  	unsigned int nbytes = walk->nbytes;
  
  	pagefault_disable();
  	enable_kernel_altivec();
  	enable_kernel_vsx();
  	aes_p8_encrypt(ctrblk, keystream, &ctx->enc_key);
  	pagefault_enable();
  
  	crypto_xor(keystream, src, nbytes);
  	memcpy(dst, keystream, nbytes);
  	crypto_inc(ctrblk, AES_BLOCK_SIZE);
  }
  
  static int p8_aes_ctr_crypt(struct blkcipher_desc *desc,
  			    struct scatterlist *dst,
  			    struct scatterlist *src, unsigned int nbytes)
  {
  	int ret;
  	u64 inc;
  	struct blkcipher_walk walk;
  	struct p8_aes_ctr_ctx *ctx =
  		crypto_tfm_ctx(crypto_blkcipher_tfm(desc->tfm));
  	struct blkcipher_desc fallback_desc = {
  		.tfm = ctx->fallback,
  		.info = desc->info,
  		.flags = desc->flags
  	};
  
  	if (in_interrupt()) {
  		ret = crypto_blkcipher_encrypt(&fallback_desc, dst, src,
  					       nbytes);
  	} else {
  		blkcipher_walk_init(&walk, dst, src, nbytes);
  		ret = blkcipher_walk_virt_block(desc, &walk, AES_BLOCK_SIZE);
  		while ((nbytes = walk.nbytes) >= AES_BLOCK_SIZE) {
  			pagefault_disable();
  			enable_kernel_altivec();
  			enable_kernel_vsx();
  			aes_p8_ctr32_encrypt_blocks(walk.src.virt.addr,
  						    walk.dst.virt.addr,
  						    (nbytes &
  						     AES_BLOCK_MASK) /
  						    AES_BLOCK_SIZE,
  						    &ctx->enc_key,
  						    walk.iv);
  			pagefault_enable();
  
  			/* We need to update IV mostly for last bytes/round */
  			inc = (nbytes & AES_BLOCK_MASK) / AES_BLOCK_SIZE;
  			if (inc > 0)
  				while (inc--)
  					crypto_inc(walk.iv, AES_BLOCK_SIZE);
  
  			nbytes &= AES_BLOCK_SIZE - 1;
  			ret = blkcipher_walk_done(desc, &walk, nbytes);
  		}
  		if (walk.nbytes) {
  			p8_aes_ctr_final(ctx, &walk);
  			ret = blkcipher_walk_done(desc, &walk, 0);
  		}
  	}
  
  	return ret;
  }
  
  struct crypto_alg p8_aes_ctr_alg = {
  	.cra_name = "ctr(aes)",
  	.cra_driver_name = "p8_aes_ctr",
  	.cra_module = THIS_MODULE,
  	.cra_priority = 2000,
  	.cra_type = &crypto_blkcipher_type,
  	.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER | CRYPTO_ALG_NEED_FALLBACK,
  	.cra_alignmask = 0,
  	.cra_blocksize = 1,
  	.cra_ctxsize = sizeof(struct p8_aes_ctr_ctx),
  	.cra_init = p8_aes_ctr_init,
  	.cra_exit = p8_aes_ctr_exit,
  	.cra_blkcipher = {
  			  .ivsize = AES_BLOCK_SIZE,
  			  .min_keysize = AES_MIN_KEY_SIZE,
  			  .max_keysize = AES_MAX_KEY_SIZE,
  			  .setkey = p8_aes_ctr_setkey,
  			  .encrypt = p8_aes_ctr_crypt,
  			  .decrypt = p8_aes_ctr_crypt,
  	},
  };