cast5_avx_glue.c

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/*
 * Glue Code for the AVX assembler implemention of the Cast5 Cipher
 *
 * Copyright (C) 2012 Johannes Goetzfried
 *     <[email protected]>
 *
 * 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; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307
 * USA
 *
 */

#include <linux/module.h>
#include <linux/hardirq.h>
#include <linux/types.h>
#include <linux/crypto.h>
#include <linux/err.h>
#include <crypto/algapi.h>
#include <crypto/cast5.h>
#include <crypto/cryptd.h>
#include <crypto/ctr.h>
#include <asm/xcr.h>
#include <asm/xsave.h>
#include <asm/crypto/ablk_helper.h>
#include <asm/crypto/glue_helper.h>

#define CAST5_PARALLEL_BLOCKS 16

asmlinkage void __cast5_enc_blk_16way(struct cast5_ctx *ctx, u8 *dst,
                      const u8 *src, bool xor);
asmlinkage void cast5_dec_blk_16way(struct cast5_ctx *ctx, u8 *dst,
                    const u8 *src);

static inline void cast5_enc_blk_xway(struct cast5_ctx *ctx, u8 *dst,
                      const u8 *src)
{
    __cast5_enc_blk_16way(ctx, dst, src, false);
}

static inline void cast5_enc_blk_xway_xor(struct cast5_ctx *ctx, u8 *dst,
                      const u8 *src)
{
    __cast5_enc_blk_16way(ctx, dst, src, true);
}

static inline void cast5_dec_blk_xway(struct cast5_ctx *ctx, u8 *dst,
                      const u8 *src)
{
    cast5_dec_blk_16way(ctx, dst, src);
}


static inline bool cast5_fpu_begin(bool fpu_enabled, unsigned int nbytes)
{
    return glue_fpu_begin(CAST5_BLOCK_SIZE, CAST5_PARALLEL_BLOCKS,
                  NULL, fpu_enabled, nbytes);
}

static inline void cast5_fpu_end(bool fpu_enabled)
{
    return glue_fpu_end(fpu_enabled);
}

static int ecb_crypt(struct blkcipher_desc *desc, struct blkcipher_walk *walk,
             bool enc)
{
    bool fpu_enabled = false;
    struct cast5_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
    const unsigned int bsize = CAST5_BLOCK_SIZE;
    unsigned int nbytes;
    int err;

    err = blkcipher_walk_virt(desc, walk);
    desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;

    while ((nbytes = walk->nbytes)) {
        u8 *wsrc = walk->src.virt.addr;
        u8 *wdst = walk->dst.virt.addr;

        fpu_enabled = cast5_fpu_begin(fpu_enabled, nbytes);

        /* Process multi-block batch */
        if (nbytes >= bsize * CAST5_PARALLEL_BLOCKS) {
            do {
                if (enc)
                    cast5_enc_blk_xway(ctx, wdst, wsrc);
                else
                    cast5_dec_blk_xway(ctx, wdst, wsrc);

                wsrc += bsize * CAST5_PARALLEL_BLOCKS;
                wdst += bsize * CAST5_PARALLEL_BLOCKS;
                nbytes -= bsize * CAST5_PARALLEL_BLOCKS;
            } while (nbytes >= bsize * CAST5_PARALLEL_BLOCKS);

            if (nbytes < bsize)
                goto done;
        }

        /* Handle leftovers */
        do {
            if (enc)
                __cast5_encrypt(ctx, wdst, wsrc);
            else
                __cast5_decrypt(ctx, wdst, wsrc);

            wsrc += bsize;
            wdst += bsize;
            nbytes -= bsize;
        } while (nbytes >= bsize);

done:
        err = blkcipher_walk_done(desc, walk, nbytes);
    }

    cast5_fpu_end(fpu_enabled);
    return err;
}

static int ecb_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
               struct scatterlist *src, unsigned int nbytes)
{
    struct blkcipher_walk walk;

    blkcipher_walk_init(&walk, dst, src, nbytes);
    return ecb_crypt(desc, &walk, true);
}

static int ecb_decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
               struct scatterlist *src, unsigned int nbytes)
{
    struct blkcipher_walk walk;

    blkcipher_walk_init(&walk, dst, src, nbytes);
    return ecb_crypt(desc, &walk, false);
}

static unsigned int __cbc_encrypt(struct blkcipher_desc *desc,
                  struct blkcipher_walk *walk)
{
    struct cast5_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
    const unsigned int bsize = CAST5_BLOCK_SIZE;
    unsigned int nbytes = walk->nbytes;
    u64 *src = (u64 *)walk->src.virt.addr;
    u64 *dst = (u64 *)walk->dst.virt.addr;
    u64 *iv = (u64 *)walk->iv;

    do {
        *dst = *src ^ *iv;
        __cast5_encrypt(ctx, (u8 *)dst, (u8 *)dst);
        iv = dst;

        src += 1;
        dst += 1;
        nbytes -= bsize;
    } while (nbytes >= bsize);

    *(u64 *)walk->iv = *iv;
    return nbytes;
}

static int cbc_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
               struct scatterlist *src, unsigned int nbytes)
{
    struct blkcipher_walk walk;
    int err;

    blkcipher_walk_init(&walk, dst, src, nbytes);
    err = blkcipher_walk_virt(desc, &walk);

    while ((nbytes = walk.nbytes)) {
        nbytes = __cbc_encrypt(desc, &walk);
        err = blkcipher_walk_done(desc, &walk, nbytes);
    }

    return err;
}

static unsigned int __cbc_decrypt(struct blkcipher_desc *desc,
                  struct blkcipher_walk *walk)
{
    struct cast5_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
    const unsigned int bsize = CAST5_BLOCK_SIZE;
    unsigned int nbytes = walk->nbytes;
    u64 *src = (u64 *)walk->src.virt.addr;
    u64 *dst = (u64 *)walk->dst.virt.addr;
    u64 ivs[CAST5_PARALLEL_BLOCKS - 1];
    u64 last_iv;
    int i;

    /* Start of the last block. */
    src += nbytes / bsize - 1;
    dst += nbytes / bsize - 1;

    last_iv = *src;

    /* Process multi-block batch */
    if (nbytes >= bsize * CAST5_PARALLEL_BLOCKS) {
        do {
            nbytes -= bsize * (CAST5_PARALLEL_BLOCKS - 1);
            src -= CAST5_PARALLEL_BLOCKS - 1;
            dst -= CAST5_PARALLEL_BLOCKS - 1;

            for (i = 0; i < CAST5_PARALLEL_BLOCKS - 1; i++)
                ivs[i] = src[i];

            cast5_dec_blk_xway(ctx, (u8 *)dst, (u8 *)src);

            for (i = 0; i < CAST5_PARALLEL_BLOCKS - 1; i++)
                *(dst + (i + 1)) ^= *(ivs + i);

            nbytes -= bsize;
            if (nbytes < bsize)
                goto done;

            *dst ^= *(src - 1);
            src -= 1;
            dst -= 1;
        } while (nbytes >= bsize * CAST5_PARALLEL_BLOCKS);

        if (nbytes < bsize)
            goto done;
    }

    /* Handle leftovers */
    for (;;) {
        __cast5_decrypt(ctx, (u8 *)dst, (u8 *)src);

        nbytes -= bsize;
        if (nbytes < bsize)
            break;

        *dst ^= *(src - 1);
        src -= 1;
        dst -= 1;
    }

done:
    *dst ^= *(u64 *)walk->iv;
    *(u64 *)walk->iv = last_iv;

    return nbytes;
}

static int cbc_decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
               struct scatterlist *src, unsigned int nbytes)
{
    bool fpu_enabled = false;
    struct blkcipher_walk walk;
    int err;

    blkcipher_walk_init(&walk, dst, src, nbytes);
    err = blkcipher_walk_virt(desc, &walk);
    desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;

    while ((nbytes = walk.nbytes)) {
        fpu_enabled = cast5_fpu_begin(fpu_enabled, nbytes);
        nbytes = __cbc_decrypt(desc, &walk);
        err = blkcipher_walk_done(desc, &walk, nbytes);
    }

    cast5_fpu_end(fpu_enabled);
    return err;
}

static void ctr_crypt_final(struct blkcipher_desc *desc,
                struct blkcipher_walk *walk)
{
    struct cast5_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
    u8 *ctrblk = walk->iv;
    u8 keystream[CAST5_BLOCK_SIZE];
    u8 *src = walk->src.virt.addr;
    u8 *dst = walk->dst.virt.addr;
    unsigned int nbytes = walk->nbytes;

    __cast5_encrypt(ctx, keystream, ctrblk);
    crypto_xor(keystream, src, nbytes);
    memcpy(dst, keystream, nbytes);

    crypto_inc(ctrblk, CAST5_BLOCK_SIZE);
}

static unsigned int __ctr_crypt(struct blkcipher_desc *desc,
                struct blkcipher_walk *walk)
{
    struct cast5_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
    const unsigned int bsize = CAST5_BLOCK_SIZE;
    unsigned int nbytes = walk->nbytes;
    u64 *src = (u64 *)walk->src.virt.addr;
    u64 *dst = (u64 *)walk->dst.virt.addr;
    u64 ctrblk = be64_to_cpu(*(__be64 *)walk->iv);
    __be64 ctrblocks[CAST5_PARALLEL_BLOCKS];
    int i;

    /* Process multi-block batch */
    if (nbytes >= bsize * CAST5_PARALLEL_BLOCKS) {
        do {
            /* create ctrblks for parallel encrypt */
            for (i = 0; i < CAST5_PARALLEL_BLOCKS; i++) {
                if (dst != src)
                    dst[i] = src[i];

                ctrblocks[i] = cpu_to_be64(ctrblk++);
            }

            cast5_enc_blk_xway_xor(ctx, (u8 *)dst,
                           (u8 *)ctrblocks);

            src += CAST5_PARALLEL_BLOCKS;
            dst += CAST5_PARALLEL_BLOCKS;
            nbytes -= bsize * CAST5_PARALLEL_BLOCKS;
        } while (nbytes >= bsize * CAST5_PARALLEL_BLOCKS);

        if (nbytes < bsize)
            goto done;
    }

    /* Handle leftovers */
    do {
        if (dst != src)
            *dst = *src;

        ctrblocks[0] = cpu_to_be64(ctrblk++);

        __cast5_encrypt(ctx, (u8 *)ctrblocks, (u8 *)ctrblocks);
        *dst ^= ctrblocks[0];

        src += 1;
        dst += 1;
        nbytes -= bsize;
    } while (nbytes >= bsize);

done:
    *(__be64 *)walk->iv = cpu_to_be64(ctrblk);
    return nbytes;
}

static int ctr_crypt(struct blkcipher_desc *desc, struct scatterlist *dst,
             struct scatterlist *src, unsigned int nbytes)
{
    bool fpu_enabled = false;
    struct blkcipher_walk walk;
    int err;

    blkcipher_walk_init(&walk, dst, src, nbytes);
    err = blkcipher_walk_virt_block(desc, &walk, CAST5_BLOCK_SIZE);
    desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;

    while ((nbytes = walk.nbytes) >= CAST5_BLOCK_SIZE) {
        fpu_enabled = cast5_fpu_begin(fpu_enabled, nbytes);
        nbytes = __ctr_crypt(desc, &walk);
        err = blkcipher_walk_done(desc, &walk, nbytes);
    }

    cast5_fpu_end(fpu_enabled);

    if (walk.nbytes) {
        ctr_crypt_final(desc, &walk);
        err = blkcipher_walk_done(desc, &walk, 0);
    }

    return err;
}


static struct crypto_alg cast5_algs[6] = { {
    .cra_name       = "__ecb-cast5-avx",
    .cra_driver_name    = "__driver-ecb-cast5-avx",
    .cra_priority       = 0,
    .cra_flags      = CRYPTO_ALG_TYPE_BLKCIPHER,
    .cra_blocksize      = CAST5_BLOCK_SIZE,
    .cra_ctxsize        = sizeof(struct cast5_ctx),
    .cra_alignmask      = 0,
    .cra_type       = &crypto_blkcipher_type,
    .cra_module     = THIS_MODULE,
    .cra_u = {
        .blkcipher = {
            .min_keysize    = CAST5_MIN_KEY_SIZE,
            .max_keysize    = CAST5_MAX_KEY_SIZE,
            .setkey     = cast5_setkey,
            .encrypt    = ecb_encrypt,
            .decrypt    = ecb_decrypt,
        },
    },
}, {
    .cra_name       = "__cbc-cast5-avx",
    .cra_driver_name    = "__driver-cbc-cast5-avx",
    .cra_priority       = 0,
    .cra_flags      = CRYPTO_ALG_TYPE_BLKCIPHER,
    .cra_blocksize      = CAST5_BLOCK_SIZE,
    .cra_ctxsize        = sizeof(struct cast5_ctx),
    .cra_alignmask      = 0,
    .cra_type       = &crypto_blkcipher_type,
    .cra_module     = THIS_MODULE,
    .cra_u = {
        .blkcipher = {
            .min_keysize    = CAST5_MIN_KEY_SIZE,
            .max_keysize    = CAST5_MAX_KEY_SIZE,
            .setkey     = cast5_setkey,
            .encrypt    = cbc_encrypt,
            .decrypt    = cbc_decrypt,
        },
    },
}, {
    .cra_name       = "__ctr-cast5-avx",
    .cra_driver_name    = "__driver-ctr-cast5-avx",
    .cra_priority       = 0,
    .cra_flags      = CRYPTO_ALG_TYPE_BLKCIPHER,
    .cra_blocksize      = 1,
    .cra_ctxsize        = sizeof(struct cast5_ctx),
    .cra_alignmask      = 0,
    .cra_type       = &crypto_blkcipher_type,
    .cra_module     = THIS_MODULE,
    .cra_u = {
        .blkcipher = {
            .min_keysize    = CAST5_MIN_KEY_SIZE,
            .max_keysize    = CAST5_MAX_KEY_SIZE,
            .ivsize     = CAST5_BLOCK_SIZE,
            .setkey     = cast5_setkey,
            .encrypt    = ctr_crypt,
            .decrypt    = ctr_crypt,
        },
    },
}, {
    .cra_name       = "ecb(cast5)",
    .cra_driver_name    = "ecb-cast5-avx",
    .cra_priority       = 200,
    .cra_flags      = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC,
    .cra_blocksize      = CAST5_BLOCK_SIZE,
    .cra_ctxsize        = sizeof(struct async_helper_ctx),
    .cra_alignmask      = 0,
    .cra_type       = &crypto_ablkcipher_type,
    .cra_module     = THIS_MODULE,
    .cra_init       = ablk_init,
    .cra_exit       = ablk_exit,
    .cra_u = {
        .ablkcipher = {
            .min_keysize    = CAST5_MIN_KEY_SIZE,
            .max_keysize    = CAST5_MAX_KEY_SIZE,
            .setkey     = ablk_set_key,
            .encrypt    = ablk_encrypt,
            .decrypt    = ablk_decrypt,
        },
    },
}, {
    .cra_name       = "cbc(cast5)",
    .cra_driver_name    = "cbc-cast5-avx",
    .cra_priority       = 200,
    .cra_flags      = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC,
    .cra_blocksize      = CAST5_BLOCK_SIZE,
    .cra_ctxsize        = sizeof(struct async_helper_ctx),
    .cra_alignmask      = 0,
    .cra_type       = &crypto_ablkcipher_type,
    .cra_module     = THIS_MODULE,
    .cra_init       = ablk_init,
    .cra_exit       = ablk_exit,
    .cra_u = {
        .ablkcipher = {
            .min_keysize    = CAST5_MIN_KEY_SIZE,
            .max_keysize    = CAST5_MAX_KEY_SIZE,
            .ivsize     = CAST5_BLOCK_SIZE,
            .setkey     = ablk_set_key,
            .encrypt    = __ablk_encrypt,
            .decrypt    = ablk_decrypt,
        },
    },
}, {
    .cra_name       = "ctr(cast5)",
    .cra_driver_name    = "ctr-cast5-avx",
    .cra_priority       = 200,
    .cra_flags      = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC,
    .cra_blocksize      = 1,
    .cra_ctxsize        = sizeof(struct async_helper_ctx),
    .cra_alignmask      = 0,
    .cra_type       = &crypto_ablkcipher_type,
    .cra_module     = THIS_MODULE,
    .cra_init       = ablk_init,
    .cra_exit       = ablk_exit,
    .cra_u = {
        .ablkcipher = {
            .min_keysize    = CAST5_MIN_KEY_SIZE,
            .max_keysize    = CAST5_MAX_KEY_SIZE,
            .ivsize     = CAST5_BLOCK_SIZE,
            .setkey     = ablk_set_key,
            .encrypt    = ablk_encrypt,
            .decrypt    = ablk_encrypt,
            .geniv      = "chainiv",
        },
    },
} };

static int __init cast5_init(void)
{
    u64 xcr0;

    if (!cpu_has_avx || !cpu_has_osxsave) {
        pr_info("AVX instructions are not detected.\n");
        return -ENODEV;
    }

    xcr0 = xgetbv(XCR_XFEATURE_ENABLED_MASK);
    if ((xcr0 & (XSTATE_SSE | XSTATE_YMM)) != (XSTATE_SSE | XSTATE_YMM)) {
        pr_info("AVX detected but unusable.\n");
        return -ENODEV;
    }

    return crypto_register_algs(cast5_algs, ARRAY_SIZE(cast5_algs));
}

static void __exit cast5_exit(void)
{
    crypto_unregister_algs(cast5_algs, ARRAY_SIZE(cast5_algs));
}

module_init(cast5_init);
module_exit(cast5_exit);

MODULE_DESCRIPTION("Cast5 Cipher Algorithm, AVX optimized");
MODULE_LICENSE("GPL");
MODULE_ALIAS("cast5");