ghash-clmulni-intel_glue.c

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/*
 * Accelerated GHASH implementation with Intel PCLMULQDQ-NI
 * instructions. This file contains glue code.
 *
 * Copyright (c) 2009 Intel Corp.
 *   Author: Huang Ying <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published
 * by the Free Software Foundation.
 */

#include <linux/err.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/crypto.h>
#include <crypto/algapi.h>
#include <crypto/cryptd.h>
#include <crypto/gf128mul.h>
#include <crypto/internal/hash.h>
#include <asm/i387.h>
#include <asm/cpu_device_id.h>

#define GHASH_BLOCK_SIZE    16
#define GHASH_DIGEST_SIZE   16

void clmul_ghash_mul(char *dst, const be128 *shash);

void clmul_ghash_update(char *dst, const char *src, unsigned int srclen,
            const be128 *shash);

void clmul_ghash_setkey(be128 *shash, const u8 *key);

struct ghash_async_ctx {
    struct cryptd_ahash *cryptd_tfm;
};

struct ghash_ctx {
    be128 shash;
};

struct ghash_desc_ctx {
    u8 buffer[GHASH_BLOCK_SIZE];
    u32 bytes;
};

static int ghash_init(struct shash_desc *desc)
{
    struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);

    memset(dctx, 0, sizeof(*dctx));

    return 0;
}

static int ghash_setkey(struct crypto_shash *tfm,
            const u8 *key, unsigned int keylen)
{
    struct ghash_ctx *ctx = crypto_shash_ctx(tfm);

    if (keylen != GHASH_BLOCK_SIZE) {
        crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
        return -EINVAL;
    }

    clmul_ghash_setkey(&ctx->shash, key);

    return 0;
}

static int ghash_update(struct shash_desc *desc,
             const u8 *src, unsigned int srclen)
{
    struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
    struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
    u8 *dst = dctx->buffer;

    kernel_fpu_begin();
    if (dctx->bytes) {
        int n = min(srclen, dctx->bytes);
        u8 *pos = dst + (GHASH_BLOCK_SIZE - dctx->bytes);

        dctx->bytes -= n;
        srclen -= n;

        while (n--)
            *pos++ ^= *src++;

        if (!dctx->bytes)
            clmul_ghash_mul(dst, &ctx->shash);
    }

    clmul_ghash_update(dst, src, srclen, &ctx->shash);
    kernel_fpu_end();

    if (srclen & 0xf) {
        src += srclen - (srclen & 0xf);
        srclen &= 0xf;
        dctx->bytes = GHASH_BLOCK_SIZE - srclen;
        while (srclen--)
            *dst++ ^= *src++;
    }

    return 0;
}

static void ghash_flush(struct ghash_ctx *ctx, struct ghash_desc_ctx *dctx)
{
    u8 *dst = dctx->buffer;

    if (dctx->bytes) {
        u8 *tmp = dst + (GHASH_BLOCK_SIZE - dctx->bytes);

        while (dctx->bytes--)
            *tmp++ ^= 0;

        kernel_fpu_begin();
        clmul_ghash_mul(dst, &ctx->shash);
        kernel_fpu_end();
    }

    dctx->bytes = 0;
}

static int ghash_final(struct shash_desc *desc, u8 *dst)
{
    struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
    struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
    u8 *buf = dctx->buffer;

    ghash_flush(ctx, dctx);
    memcpy(dst, buf, GHASH_BLOCK_SIZE);

    return 0;
}

static struct shash_alg ghash_alg = {
    .digestsize = GHASH_DIGEST_SIZE,
    .init       = ghash_init,
    .update     = ghash_update,
    .final      = ghash_final,
    .setkey     = ghash_setkey,
    .descsize   = sizeof(struct ghash_desc_ctx),
    .base       = {
        .cra_name       = "__ghash",
        .cra_driver_name    = "__ghash-pclmulqdqni",
        .cra_priority       = 0,
        .cra_flags      = CRYPTO_ALG_TYPE_SHASH,
        .cra_blocksize      = GHASH_BLOCK_SIZE,
        .cra_ctxsize        = sizeof(struct ghash_ctx),
        .cra_module     = THIS_MODULE,
    },
};

static int ghash_async_init(struct ahash_request *req)
{
    struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
    struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
    struct ahash_request *cryptd_req = ahash_request_ctx(req);
    struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;

    if (!irq_fpu_usable()) {
        memcpy(cryptd_req, req, sizeof(*req));
        ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
        return crypto_ahash_init(cryptd_req);
    } else {
        struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
        struct crypto_shash *child = cryptd_ahash_child(cryptd_tfm);

        desc->tfm = child;
        desc->flags = req->base.flags;
        return crypto_shash_init(desc);
    }
}

static int ghash_async_update(struct ahash_request *req)
{
    struct ahash_request *cryptd_req = ahash_request_ctx(req);

    if (!irq_fpu_usable()) {
        struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
        struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
        struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;

        memcpy(cryptd_req, req, sizeof(*req));
        ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
        return crypto_ahash_update(cryptd_req);
    } else {
        struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
        return shash_ahash_update(req, desc);
    }
}

static int ghash_async_final(struct ahash_request *req)
{
    struct ahash_request *cryptd_req = ahash_request_ctx(req);

    if (!irq_fpu_usable()) {
        struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
        struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
        struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;

        memcpy(cryptd_req, req, sizeof(*req));
        ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
        return crypto_ahash_final(cryptd_req);
    } else {
        struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
        return crypto_shash_final(desc, req->result);
    }
}

static int ghash_async_digest(struct ahash_request *req)
{
    struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
    struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
    struct ahash_request *cryptd_req = ahash_request_ctx(req);
    struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;

    if (!irq_fpu_usable()) {
        memcpy(cryptd_req, req, sizeof(*req));
        ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
        return crypto_ahash_digest(cryptd_req);
    } else {
        struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
        struct crypto_shash *child = cryptd_ahash_child(cryptd_tfm);

        desc->tfm = child;
        desc->flags = req->base.flags;
        return shash_ahash_digest(req, desc);
    }
}

static int ghash_async_setkey(struct crypto_ahash *tfm, const u8 *key,
                  unsigned int keylen)
{
    struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
    struct crypto_ahash *child = &ctx->cryptd_tfm->base;
    int err;

    crypto_ahash_clear_flags(child, CRYPTO_TFM_REQ_MASK);
    crypto_ahash_set_flags(child, crypto_ahash_get_flags(tfm)
                   & CRYPTO_TFM_REQ_MASK);
    err = crypto_ahash_setkey(child, key, keylen);
    crypto_ahash_set_flags(tfm, crypto_ahash_get_flags(child)
                   & CRYPTO_TFM_RES_MASK);

    return err;
}

static int ghash_async_init_tfm(struct crypto_tfm *tfm)
{
    struct cryptd_ahash *cryptd_tfm;
    struct ghash_async_ctx *ctx = crypto_tfm_ctx(tfm);

    cryptd_tfm = cryptd_alloc_ahash("__ghash-pclmulqdqni", 0, 0);
    if (IS_ERR(cryptd_tfm))
        return PTR_ERR(cryptd_tfm);
    ctx->cryptd_tfm = cryptd_tfm;
    crypto_ahash_set_reqsize(__crypto_ahash_cast(tfm),
                 sizeof(struct ahash_request) +
                 crypto_ahash_reqsize(&cryptd_tfm->base));

    return 0;
}

static void ghash_async_exit_tfm(struct crypto_tfm *tfm)
{
    struct ghash_async_ctx *ctx = crypto_tfm_ctx(tfm);

    cryptd_free_ahash(ctx->cryptd_tfm);
}

static struct ahash_alg ghash_async_alg = {
    .init       = ghash_async_init,
    .update     = ghash_async_update,
    .final      = ghash_async_final,
    .setkey     = ghash_async_setkey,
    .digest     = ghash_async_digest,
    .halg = {
        .digestsize = GHASH_DIGEST_SIZE,
        .base = {
            .cra_name       = "ghash",
            .cra_driver_name    = "ghash-clmulni",
            .cra_priority       = 400,
            .cra_flags      = CRYPTO_ALG_TYPE_AHASH | CRYPTO_ALG_ASYNC,
            .cra_blocksize      = GHASH_BLOCK_SIZE,
            .cra_type       = &crypto_ahash_type,
            .cra_module     = THIS_MODULE,
            .cra_init       = ghash_async_init_tfm,
            .cra_exit       = ghash_async_exit_tfm,
        },
    },
};

static const struct x86_cpu_id pcmul_cpu_id[] = {
    X86_FEATURE_MATCH(X86_FEATURE_PCLMULQDQ), /* Pickle-Mickle-Duck */
    {}
};
MODULE_DEVICE_TABLE(x86cpu, pcmul_cpu_id);

static int __init ghash_pclmulqdqni_mod_init(void)
{
    int err;

    if (!x86_match_cpu(pcmul_cpu_id))
        return -ENODEV;

    err = crypto_register_shash(&ghash_alg);
    if (err)
        goto err_out;
    err = crypto_register_ahash(&ghash_async_alg);
    if (err)
        goto err_shash;

    return 0;

err_shash:
    crypto_unregister_shash(&ghash_alg);
err_out:
    return err;
}

static void __exit ghash_pclmulqdqni_mod_exit(void)
{
    crypto_unregister_ahash(&ghash_async_alg);
    crypto_unregister_shash(&ghash_alg);
}

module_init(ghash_pclmulqdqni_mod_init);
module_exit(ghash_pclmulqdqni_mod_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("GHASH Message Digest Algorithm, "
           "acclerated by PCLMULQDQ-NI");
MODULE_ALIAS("ghash");