diff options
Diffstat (limited to 'drivers/crypto/vmx/aes_ctr.c')
| -rw-r--r-- | drivers/crypto/vmx/aes_ctr.c | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/drivers/crypto/vmx/aes_ctr.c b/drivers/crypto/vmx/aes_ctr.c new file mode 100644 index 000000000..cd777c752 --- /dev/null +++ b/drivers/crypto/vmx/aes_ctr.c @@ -0,0 +1,184 @@ +/** + * 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 <crypto/skcipher.h> + +#include "aesp8-ppc.h" + +struct p8_aes_ctr_ctx { + struct crypto_skcipher *fallback; + struct aes_key enc_key; +}; + +static int p8_aes_ctr_init(struct crypto_tfm *tfm) +{ + const char *alg = crypto_tfm_alg_name(tfm); + struct crypto_skcipher *fallback; + struct p8_aes_ctr_ctx *ctx = crypto_tfm_ctx(tfm); + + fallback = crypto_alloc_skcipher(alg, 0, + CRYPTO_ALG_ASYNC | 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_skcipher_set_flags( + fallback, + crypto_skcipher_get_flags((struct crypto_skcipher *)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_skcipher(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); + + preempt_disable(); + pagefault_disable(); + enable_kernel_vsx(); + ret = aes_p8_set_encrypt_key(key, keylen * 8, &ctx->enc_key); + disable_kernel_vsx(); + pagefault_enable(); + preempt_enable(); + + ret += crypto_skcipher_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; + + preempt_disable(); + pagefault_disable(); + enable_kernel_vsx(); + aes_p8_encrypt(ctrblk, keystream, &ctx->enc_key); + disable_kernel_vsx(); + pagefault_enable(); + preempt_enable(); + + crypto_xor_cpy(dst, keystream, src, 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)); + + if (in_interrupt()) { + SKCIPHER_REQUEST_ON_STACK(req, ctx->fallback); + skcipher_request_set_tfm(req, ctx->fallback); + skcipher_request_set_callback(req, desc->flags, NULL, NULL); + skcipher_request_set_crypt(req, src, dst, nbytes, desc->info); + ret = crypto_skcipher_encrypt(req); + skcipher_request_zero(req); + } 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) { + preempt_disable(); + pagefault_disable(); + 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); + disable_kernel_vsx(); + pagefault_enable(); + preempt_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, + }, +}; |