Re: [PATCH] arm64: crypto: Add ARM64 CRC32 hw accelerated module

[Ard Biesheuvel]

On 20 November 2014 15:22, Yazen Ghannam <yazen.ghannam@xxxxxxxxxx> wrote:
> +linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
>
> On Wed, Nov 19, 2014 at 11:19 AM, Yazen Ghannam
> <yazen.ghannam@xxxxxxxxxx> wrote:
>> This module registers a crc32 algorithm and a crc32c algorithm
>> that use the optional CRC32 and CRC32C instructions in ARMv8.
>>
>> Tested on AMD Seattle.
>>
>> Improvement compared to crc32c-generic algorithm:
>> TCRYPT CRC32C speed test shows ~450% speedup.
>> Simple dd write tests to btrfs filesystem show ~30% speedup.
>>
>> Signed-off-by: Yazen Ghannam <yazen.ghannam@xxxxxxxxxx>
>> Acked-by: Steve Capper <steve.capper@xxxxxxxxxx>
>> Acked-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
>> ---
>>  arch/arm64/crypto/Kconfig       |   4 +
>>  arch/arm64/crypto/Makefile      |   4 +
>>  arch/arm64/crypto/crc32-arm64.c | 274 ++++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 282 insertions(+)
>>  create mode 100644 arch/arm64/crypto/crc32-arm64.c
>>
>> diff --git a/arch/arm64/crypto/Kconfig b/arch/arm64/crypto/Kconfig
>> index 5562652..c1a0468 100644
>> --- a/arch/arm64/crypto/Kconfig
>> +++ b/arch/arm64/crypto/Kconfig
>> @@ -50,4 +50,8 @@ config CRYPTO_AES_ARM64_NEON_BLK
>>         select CRYPTO_AES
>>         select CRYPTO_ABLK_HELPER
>>
>> +config CRYPTO_CRC32_ARM64
>> +       tristate "CRC32 and CRC32C using optional ARMv8 instructions"
>> +       depends on ARM64
>> +       select CRYPTO_HASH
>>  endif
>> diff --git a/arch/arm64/crypto/Makefile b/arch/arm64/crypto/Makefile
>> index a3f935f..5720608 100644
>> --- a/arch/arm64/crypto/Makefile
>> +++ b/arch/arm64/crypto/Makefile
>> @@ -34,5 +34,9 @@ AFLAGS_aes-neon.o     := -DINTERLEAVE=4
>>
>>  CFLAGS_aes-glue-ce.o   := -DUSE_V8_CRYPTO_EXTENSIONS
>>
>> +obj-$(CONFIG_CRYPTO_CRC32_ARM64) += crc32-arm64.o
>> +
>> +CFLAGS_crc32-arm64.o   := -mcpu=generic+crc
>> +
>>  $(obj)/aes-glue-%.o: $(src)/aes-glue.c FORCE
>>         $(call if_changed_rule,cc_o_c)
>> diff --git a/arch/arm64/crypto/crc32-arm64.c b/arch/arm64/crypto/crc32-arm64.c
>> new file mode 100644
>> index 0000000..9499199
>> --- /dev/null
>> +++ b/arch/arm64/crypto/crc32-arm64.c
>> @@ -0,0 +1,274 @@
>> +/*
>> + * crc32-arm64.c - CRC32 and CRC32C using optional ARMv8 instructions
>> + *
>> + * Module based on crypto/crc32c_generic.c
>> + *
>> + * CRC32 loop taken from Ed Nevill's Hadoop CRC patch
>> + * http://mail-archives.apache.org/mod_mbox/hadoop-common-dev/201406.mbox/%3C1403687030.3355.19.camel%40localhost.localdomain%3E
>> + *
>> + * Using inline assembly instead of intrinsics in order to be backwards
>> + * compatible with older compilers.
>> + *
>> + * Copyright (C) 2014 Linaro Ltd <yazen.ghannam@xxxxxxxxxx>
>> + *
>> + * 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/unaligned/access_ok.h>

One final nit: you should not be including this file directly.
You should include <asm/unaligned.h> instead, and it is up to the
architecture to include either access_ok.h or another implementation
of get_unaligned_leXX

Granted, the distinction is fairly artificial on arm64, but it does
increase the portability of the code.

-- 
Ard.


>> +#include <linux/cpufeature.h>
>> +#include <linux/init.h>
>> +#include <linux/kernel.h>
>> +#include <linux/module.h>
>> +#include <linux/string.h>
>> +
>> +#include <crypto/internal/hash.h>
>> +
>> +MODULE_AUTHOR("Yazen Ghannam <yazen.ghannam@xxxxxxxxxx>");
>> +MODULE_DESCRIPTION("CRC32 and CRC32C using optional ARMv8 instructions");
>> +MODULE_LICENSE("GPL v2");
>> +
>> +#define CRC32X(crc, value) __asm__("crc32x %w[c], %w[c], %x[v]":[c]"+r"(crc):[v]"r"(value))
>> +#define CRC32W(crc, value) __asm__("crc32w %w[c], %w[c], %w[v]":[c]"+r"(crc):[v]"r"(value))
>> +#define CRC32H(crc, value) __asm__("crc32h %w[c], %w[c], %w[v]":[c]"+r"(crc):[v]"r"(value))
>> +#define CRC32B(crc, value) __asm__("crc32b %w[c], %w[c], %w[v]":[c]"+r"(crc):[v]"r"(value))
>> +#define CRC32CX(crc, value) __asm__("crc32cx %w[c], %w[c], %x[v]":[c]"+r"(crc):[v]"r"(value))
>> +#define CRC32CW(crc, value) __asm__("crc32cw %w[c], %w[c], %w[v]":[c]"+r"(crc):[v]"r"(value))
>> +#define CRC32CH(crc, value) __asm__("crc32ch %w[c], %w[c], %w[v]":[c]"+r"(crc):[v]"r"(value))
>> +#define CRC32CB(crc, value) __asm__("crc32cb %w[c], %w[c], %w[v]":[c]"+r"(crc):[v]"r"(value))
>> +
>> +static u32 crc32_arm64_le_hw(u32 crc, const u8 *p, unsigned int len)
>> +{
>> +       s64 length = len;
>> +
>> +       while ((length -= sizeof(u64)) >= 0) {
>> +               CRC32X(crc, get_unaligned_le64(p));
>> +               p += sizeof(u64);
>> +       }
>> +
>> +       /* The following is more efficient than the straight loop */
>> +       if (length & sizeof(u32)) {
>> +               CRC32W(crc, get_unaligned_le32(p));
>> +               p += sizeof(u32);
>> +       }
>> +       if (length & sizeof(u16)) {
>> +               CRC32H(crc, get_unaligned_le16(p));
>> +               p += sizeof(u16);
>> +       }
>> +       if (length & sizeof(u8))
>> +               CRC32B(crc, *p);
>> +
>> +       return crc;
>> +}
>> +
>> +static u32 crc32c_arm64_le_hw(u32 crc, const u8 *p, unsigned int len)
>> +{
>> +       s64 length = len;
>> +
>> +       while ((length -= sizeof(u64)) >= 0) {
>> +               CRC32CX(crc, get_unaligned_le64(p));
>> +               p += sizeof(u64);
>> +       }
>> +
>> +       /* The following is more efficient than the straight loop */
>> +       if (length & sizeof(u32)) {
>> +               CRC32CW(crc, get_unaligned_le32(p));
>> +               p += sizeof(u32);
>> +       }
>> +       if (length & sizeof(u16)) {
>> +               CRC32CH(crc, get_unaligned_le16(p));
>> +               p += sizeof(u16);
>> +       }
>> +       if (length & sizeof(u8))
>> +               CRC32CB(crc, *p);
>> +
>> +       return crc;
>> +}
>> +
>> +#define CHKSUM_BLOCK_SIZE      1
>> +#define CHKSUM_DIGEST_SIZE     4
>> +
>> +struct chksum_ctx {
>> +       u32 key;
>> +};
>> +
>> +struct chksum_desc_ctx {
>> +       u32 crc;
>> +};
>> +
>> +static int chksum_init(struct shash_desc *desc)
>> +{
>> +       struct chksum_ctx *mctx = crypto_shash_ctx(desc->tfm);
>> +       struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
>> +
>> +       ctx->crc = mctx->key;
>> +
>> +       return 0;
>> +}
>> +
>> +/*
>> + * 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 chksum_setkey(struct crypto_shash *tfm, const u8 *key,
>> +                        unsigned int keylen)
>> +{
>> +       struct chksum_ctx *mctx = crypto_shash_ctx(tfm);
>> +
>> +       if (keylen != sizeof(mctx->key)) {
>> +               crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
>> +               return -EINVAL;
>> +       }
>> +       mctx->key = get_unaligned_le32(key);
>> +       return 0;
>> +}
>> +
>> +static int chksum_update(struct shash_desc *desc, const u8 *data,
>> +                        unsigned int length)
>> +{
>> +       struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
>> +
>> +       ctx->crc = crc32_arm64_le_hw(ctx->crc, data, length);
>> +       return 0;
>> +}
>> +
>> +static int chksumc_update(struct shash_desc *desc, const u8 *data,
>> +                        unsigned int length)
>> +{
>> +       struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
>> +
>> +       ctx->crc = crc32c_arm64_le_hw(ctx->crc, data, length);
>> +       return 0;
>> +}
>> +
>> +static int chksum_final(struct shash_desc *desc, u8 *out)
>> +{
>> +       struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
>> +
>> +       put_unaligned_le32(~ctx->crc, out);
>> +       return 0;
>> +}
>> +
>> +static int __chksum_finup(u32 crc, const u8 *data, unsigned int len, u8 *out)
>> +{
>> +       put_unaligned_le32(~crc32_arm64_le_hw(crc, data, len), out);
>> +       return 0;
>> +}
>> +
>> +static int __chksumc_finup(u32 crc, const u8 *data, unsigned int len, u8 *out)
>> +{
>> +       put_unaligned_le32(~crc32c_arm64_le_hw(crc, data, len), out);
>> +       return 0;
>> +}
>> +
>> +static int chksum_finup(struct shash_desc *desc, const u8 *data,
>> +                       unsigned int len, u8 *out)
>> +{
>> +       struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
>> +
>> +       return __chksum_finup(ctx->crc, data, len, out);
>> +}
>> +
>> +static int chksumc_finup(struct shash_desc *desc, const u8 *data,
>> +                       unsigned int len, u8 *out)
>> +{
>> +       struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
>> +
>> +       return __chksumc_finup(ctx->crc, data, len, out);
>> +}
>> +
>> +static int chksum_digest(struct shash_desc *desc, const u8 *data,
>> +                        unsigned int length, u8 *out)
>> +{
>> +       struct chksum_ctx *mctx = crypto_shash_ctx(desc->tfm);
>> +
>> +       return __chksum_finup(mctx->key, data, length, out);
>> +}
>> +
>> +static int chksumc_digest(struct shash_desc *desc, const u8 *data,
>> +                        unsigned int length, u8 *out)
>> +{
>> +       struct chksum_ctx *mctx = crypto_shash_ctx(desc->tfm);
>> +
>> +       return __chksumc_finup(mctx->key, data, length, out);
>> +}
>> +
>> +static int crc32_cra_init(struct crypto_tfm *tfm)
>> +{
>> +       struct chksum_ctx *mctx = crypto_tfm_ctx(tfm);
>> +
>> +       mctx->key = ~0;
>> +       return 0;
>> +}
>> +
>> +static struct shash_alg crc32_alg = {
>> +       .digestsize             =       CHKSUM_DIGEST_SIZE,
>> +       .setkey                 =       chksum_setkey,
>> +       .init                   =       chksum_init,
>> +       .update                 =       chksum_update,
>> +       .final                  =       chksum_final,
>> +       .finup                  =       chksum_finup,
>> +       .digest                 =       chksum_digest,
>> +       .descsize               =       sizeof(struct chksum_desc_ctx),
>> +       .base                   =       {
>> +               .cra_name               =       "crc32",
>> +               .cra_driver_name        =       "crc32-arm64-hw",
>> +               .cra_priority           =       300,
>> +               .cra_blocksize          =       CHKSUM_BLOCK_SIZE,
>> +               .cra_alignmask          =       0,
>> +               .cra_ctxsize            =       sizeof(struct chksum_ctx),
>> +               .cra_module             =       THIS_MODULE,
>> +               .cra_init               =       crc32_cra_init,
>> +       }
>> +};
>> +
>> +static struct shash_alg crc32c_alg = {
>> +       .digestsize             =       CHKSUM_DIGEST_SIZE,
>> +       .setkey                 =       chksum_setkey,
>> +       .init                   =       chksum_init,
>> +       .update                 =       chksumc_update,
>> +       .final                  =       chksum_final,
>> +       .finup                  =       chksumc_finup,
>> +       .digest                 =       chksumc_digest,
>> +       .descsize               =       sizeof(struct chksum_desc_ctx),
>> +       .base                   =       {
>> +               .cra_name               =       "crc32c",
>> +               .cra_driver_name        =       "crc32c-arm64-hw",
>> +               .cra_priority           =       300,
>> +               .cra_blocksize          =       CHKSUM_BLOCK_SIZE,
>> +               .cra_alignmask          =       0,
>> +               .cra_ctxsize            =       sizeof(struct chksum_ctx),
>> +               .cra_module             =       THIS_MODULE,
>> +               .cra_init               =       crc32_cra_init,
>> +       }
>> +};
>> +
>> +static int __init crc32_mod_init(void)
>> +{
>> +       int err;
>> +
>> +       err = crypto_register_shash(&crc32_alg);
>> +
>> +       if (err)
>> +               return err;
>> +
>> +       err = crypto_register_shash(&crc32c_alg);
>> +
>> +       if (err) {
>> +               crypto_unregister_shash(&crc32_alg);
>> +               return err;
>> +       }
>> +
>> +       return 0;
>> +}
>> +
>> +static void __exit crc32_mod_exit(void)
>> +{
>> +       crypto_unregister_shash(&crc32_alg);
>> +       crypto_unregister_shash(&crc32c_alg);
>> +}
>> +
>> +module_cpu_feature_match(CRC32, crc32_mod_init);
>> +module_exit(crc32_mod_exit);
>> --
>> 2.1.0
>>
>
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