crc32c_glue.c

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/* Glue code for CRC32C optimized for sparc64 crypto opcodes.
 *
 * This is based largely upon arch/x86/crypto/crc32c-intel.c
 *
 * Copyright (C) 2008 Intel Corporation
 * Authors: Austin Zhang <[email protected]>
 *          Kent Liu <[email protected]>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/init.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/crc32.h>

#include <crypto/internal/hash.h>

#include <asm/pstate.h>
#include <asm/elf.h>

#include "opcodes.h"

/*
 * Setting the seed allows arbitrary accumulators and flexible XOR policy
 * If your algorithm starts with ~0, then XOR with ~0 before you set
 * the seed.
 */
static int crc32c_sparc64_setkey(struct crypto_shash *hash, const u8 *key,
                 unsigned int keylen)
{
    u32 *mctx = crypto_shash_ctx(hash);

    if (keylen != sizeof(u32)) {
        crypto_shash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN);
        return -EINVAL;
    }
    *(__le32 *)mctx = le32_to_cpup((__le32 *)key);
    return 0;
}

static int crc32c_sparc64_init(struct shash_desc *desc)
{
    u32 *mctx = crypto_shash_ctx(desc->tfm);
    u32 *crcp = shash_desc_ctx(desc);

    *crcp = *mctx;

    return 0;
}

extern void crc32c_sparc64(u32 *crcp, const u64 *data, unsigned int len);

static void crc32c_compute(u32 *crcp, const u64 *data, unsigned int len)
{
    unsigned int asm_len;

    asm_len = len & ~7U;
    if (asm_len) {
        crc32c_sparc64(crcp, data, asm_len);
        data += asm_len / 8;
        len -= asm_len;
    }
    if (len)
        *crcp = __crc32c_le(*crcp, (const unsigned char *) data, len);
}

static int crc32c_sparc64_update(struct shash_desc *desc, const u8 *data,
                 unsigned int len)
{
    u32 *crcp = shash_desc_ctx(desc);

    crc32c_compute(crcp, (const u64 *) data, len);

    return 0;
}

static int __crc32c_sparc64_finup(u32 *crcp, const u8 *data, unsigned int len,
                  u8 *out)
{
    u32 tmp = *crcp;

    crc32c_compute(&tmp, (const u64 *) data, len);

    *(__le32 *) out = ~cpu_to_le32(tmp);
    return 0;
}

static int crc32c_sparc64_finup(struct shash_desc *desc, const u8 *data,
                unsigned int len, u8 *out)
{
    return __crc32c_sparc64_finup(shash_desc_ctx(desc), data, len, out);
}

static int crc32c_sparc64_final(struct shash_desc *desc, u8 *out)
{
    u32 *crcp = shash_desc_ctx(desc);

    *(__le32 *) out = ~cpu_to_le32p(crcp);
    return 0;
}

static int crc32c_sparc64_digest(struct shash_desc *desc, const u8 *data,
                 unsigned int len, u8 *out)
{
    return __crc32c_sparc64_finup(crypto_shash_ctx(desc->tfm), data, len,
                      out);
}

static int crc32c_sparc64_cra_init(struct crypto_tfm *tfm)
{
    u32 *key = crypto_tfm_ctx(tfm);

    *key = ~0;

    return 0;
}

#define CHKSUM_BLOCK_SIZE   1
#define CHKSUM_DIGEST_SIZE  4

static struct shash_alg alg = {
    .setkey         =   crc32c_sparc64_setkey,
    .init           =   crc32c_sparc64_init,
    .update         =   crc32c_sparc64_update,
    .final          =   crc32c_sparc64_final,
    .finup          =   crc32c_sparc64_finup,
    .digest         =   crc32c_sparc64_digest,
    .descsize       =   sizeof(u32),
    .digestsize     =   CHKSUM_DIGEST_SIZE,
    .base           =   {
        .cra_name       =   "crc32c",
        .cra_driver_name    =   "crc32c-sparc64",
        .cra_priority       =   SPARC_CR_OPCODE_PRIORITY,
        .cra_blocksize      =   CHKSUM_BLOCK_SIZE,
        .cra_ctxsize        =   sizeof(u32),
        .cra_alignmask      =   7,
        .cra_module     =   THIS_MODULE,
        .cra_init       =   crc32c_sparc64_cra_init,
    }
};

static bool __init sparc64_has_crc32c_opcode(void)
{
    unsigned long cfr;

    if (!(sparc64_elf_hwcap & HWCAP_SPARC_CRYPTO))
        return false;

    __asm__ __volatile__("rd %%asr26, %0" : "=r" (cfr));
    if (!(cfr & CFR_CRC32C))
        return false;

    return true;
}

static int __init crc32c_sparc64_mod_init(void)
{
    if (sparc64_has_crc32c_opcode()) {
        pr_info("Using sparc64 crc32c opcode optimized CRC32C implementation\n");
        return crypto_register_shash(&alg);
    }
    pr_info("sparc64 crc32c opcode not available.\n");
    return -ENODEV;
}

static void __exit crc32c_sparc64_mod_fini(void)
{
    crypto_unregister_shash(&alg);
}

module_init(crc32c_sparc64_mod_init);
module_exit(crc32c_sparc64_mod_fini);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("CRC32c (Castagnoli), sparc64 crc32c opcode accelerated");

MODULE_ALIAS("crc32c");

#include "crop_devid.c"