diff options
Diffstat (limited to 'arch/x86/crypto/crc32c-intel_glue.c')
| -rw-r--r-- | arch/x86/crypto/crc32c-intel_glue.c | 284 |
1 files changed, 284 insertions, 0 deletions
diff --git a/arch/x86/crypto/crc32c-intel_glue.c b/arch/x86/crypto/crc32c-intel_glue.c new file mode 100644 index 000000000000..6812ad98355c --- /dev/null +++ b/arch/x86/crypto/crc32c-intel_glue.c @@ -0,0 +1,284 @@ +/* + * Using hardware provided CRC32 instruction to accelerate the CRC32 disposal. + * CRC32C polynomial:0x1EDC6F41(BE)/0x82F63B78(LE) + * CRC32 is a new instruction in Intel SSE4.2, the reference can be found at: + * http://www.intel.com/products/processor/manuals/ + * Intel(R) 64 and IA-32 Architectures Software Developer's Manual + * Volume 2A: Instruction Set Reference, A-M + * + * Copyright (C) 2008 Intel Corporation + * Authors: Austin Zhang <austin_zhang@linux.intel.com> + * Kent Liu <kent.liu@intel.com> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope 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., + * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. + * + */ +#include <linux/init.h> +#include <linux/module.h> +#include <linux/string.h> +#include <linux/kernel.h> +#include <crypto/internal/hash.h> + +#include <asm/cpufeature.h> +#include <asm/cpu_device_id.h> +#include <asm/i387.h> +#include <asm/fpu-internal.h> + +#define CHKSUM_BLOCK_SIZE 1 +#define CHKSUM_DIGEST_SIZE 4 + +#define SCALE_F sizeof(unsigned long) + +#ifdef CONFIG_X86_64 +#define REX_PRE "0x48, " +#else +#define REX_PRE +#endif + +#ifdef CONFIG_X86_64 +/* + * use carryless multiply version of crc32c when buffer + * size is >= 512 (when eager fpu is enabled) or + * >= 1024 (when eager fpu is disabled) to account + * for fpu state save/restore overhead. + */ +#define CRC32C_PCL_BREAKEVEN_EAGERFPU 512 +#define CRC32C_PCL_BREAKEVEN_NOEAGERFPU 1024 + +asmlinkage unsigned int crc_pcl(const u8 *buffer, int len, + unsigned int crc_init); +static int crc32c_pcl_breakeven = CRC32C_PCL_BREAKEVEN_EAGERFPU; +#if defined(X86_FEATURE_EAGER_FPU) +#define set_pcl_breakeven_point() \ +do { \ + if (!use_eager_fpu()) \ + crc32c_pcl_breakeven = CRC32C_PCL_BREAKEVEN_NOEAGERFPU; \ +} while (0) +#else +#define set_pcl_breakeven_point() \ + (crc32c_pcl_breakeven = CRC32C_PCL_BREAKEVEN_NOEAGERFPU) +#endif +#endif /* CONFIG_X86_64 */ + +static u32 crc32c_intel_le_hw_byte(u32 crc, unsigned char const *data, size_t length) +{ + while (length--) { + __asm__ __volatile__( + ".byte 0xf2, 0xf, 0x38, 0xf0, 0xf1" + :"=S"(crc) + :"0"(crc), "c"(*data) + ); + data++; + } + + return crc; +} + +static u32 __pure crc32c_intel_le_hw(u32 crc, unsigned char const *p, size_t len) +{ + unsigned int iquotient = len / SCALE_F; + unsigned int iremainder = len % SCALE_F; + unsigned long *ptmp = (unsigned long *)p; + + while (iquotient--) { + __asm__ __volatile__( + ".byte 0xf2, " REX_PRE "0xf, 0x38, 0xf1, 0xf1;" + :"=S"(crc) + :"0"(crc), "c"(*ptmp) + ); + ptmp++; + } + + if (iremainder) + crc = crc32c_intel_le_hw_byte(crc, (unsigned char *)ptmp, + iremainder); + + return crc; +} + +/* + * 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_intel_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; + } + *mctx = le32_to_cpup((__le32 *)key); + return 0; +} + +static int crc32c_intel_init(struct shash_desc *desc) +{ + u32 *mctx = crypto_shash_ctx(desc->tfm); + u32 *crcp = shash_desc_ctx(desc); + + *crcp = *mctx; + + return 0; +} + +static int crc32c_intel_update(struct shash_desc *desc, const u8 *data, + unsigned int len) +{ + u32 *crcp = shash_desc_ctx(desc); + + *crcp = crc32c_intel_le_hw(*crcp, data, len); + return 0; +} + +static int __crc32c_intel_finup(u32 *crcp, const u8 *data, unsigned int len, + u8 *out) +{ + *(__le32 *)out = ~cpu_to_le32(crc32c_intel_le_hw(*crcp, data, len)); + return 0; +} + +static int crc32c_intel_finup(struct shash_desc *desc, const u8 *data, + unsigned int len, u8 *out) +{ + return __crc32c_intel_finup(shash_desc_ctx(desc), data, len, out); +} + +static int crc32c_intel_final(struct shash_desc *desc, u8 *out) +{ + u32 *crcp = shash_desc_ctx(desc); + + *(__le32 *)out = ~cpu_to_le32p(crcp); + return 0; +} + +static int crc32c_intel_digest(struct shash_desc *desc, const u8 *data, + unsigned int len, u8 *out) +{ + return __crc32c_intel_finup(crypto_shash_ctx(desc->tfm), data, len, + out); +} + +static int crc32c_intel_cra_init(struct crypto_tfm *tfm) +{ + u32 *key = crypto_tfm_ctx(tfm); + + *key = ~0; + + return 0; +} + +#ifdef CONFIG_X86_64 +static int crc32c_pcl_intel_update(struct shash_desc *desc, const u8 *data, + unsigned int len) +{ + u32 *crcp = shash_desc_ctx(desc); + + /* + * use faster PCL version if datasize is large enough to + * overcome kernel fpu state save/restore overhead + */ + if (len >= crc32c_pcl_breakeven && irq_fpu_usable()) { + kernel_fpu_begin(); + *crcp = crc_pcl(data, len, *crcp); + kernel_fpu_end(); + } else + *crcp = crc32c_intel_le_hw(*crcp, data, len); + return 0; +} + +static int __crc32c_pcl_intel_finup(u32 *crcp, const u8 *data, unsigned int len, + u8 *out) +{ + if (len >= crc32c_pcl_breakeven && irq_fpu_usable()) { + kernel_fpu_begin(); + *(__le32 *)out = ~cpu_to_le32(crc_pcl(data, len, *crcp)); + kernel_fpu_end(); + } else + *(__le32 *)out = + ~cpu_to_le32(crc32c_intel_le_hw(*crcp, data, len)); + return 0; +} + +static int crc32c_pcl_intel_finup(struct shash_desc *desc, const u8 *data, + unsigned int len, u8 *out) +{ + return __crc32c_pcl_intel_finup(shash_desc_ctx(desc), data, len, out); +} + +static int crc32c_pcl_intel_digest(struct shash_desc *desc, const u8 *data, + unsigned int len, u8 *out) +{ + return __crc32c_pcl_intel_finup(crypto_shash_ctx(desc->tfm), data, len, + out); +} +#endif /* CONFIG_X86_64 */ + +static struct shash_alg alg = { + .setkey = crc32c_intel_setkey, + .init = crc32c_intel_init, + .update = crc32c_intel_update, + .final = crc32c_intel_final, + .finup = crc32c_intel_finup, + .digest = crc32c_intel_digest, + .descsize = sizeof(u32), + .digestsize = CHKSUM_DIGEST_SIZE, + .base = { + .cra_name = "crc32c", + .cra_driver_name = "crc32c-intel", + .cra_priority = 200, + .cra_blocksize = CHKSUM_BLOCK_SIZE, + .cra_ctxsize = sizeof(u32), + .cra_module = THIS_MODULE, + .cra_init = crc32c_intel_cra_init, + } +}; + +static const struct x86_cpu_id crc32c_cpu_id[] = { + X86_FEATURE_MATCH(X86_FEATURE_XMM4_2), + {} +}; +MODULE_DEVICE_TABLE(x86cpu, crc32c_cpu_id); + +static int __init crc32c_intel_mod_init(void) +{ + if (!x86_match_cpu(crc32c_cpu_id)) + return -ENODEV; +#ifdef CONFIG_X86_64 + if (cpu_has_pclmulqdq) { + alg.update = crc32c_pcl_intel_update; + alg.finup = crc32c_pcl_intel_finup; + alg.digest = crc32c_pcl_intel_digest; + set_pcl_breakeven_point(); + } +#endif + return crypto_register_shash(&alg); +} + +static void __exit crc32c_intel_mod_fini(void) +{ + crypto_unregister_shash(&alg); +} + +module_init(crc32c_intel_mod_init); +module_exit(crc32c_intel_mod_fini); + +MODULE_AUTHOR("Austin Zhang <austin.zhang@intel.com>, Kent Liu <kent.liu@intel.com>"); +MODULE_DESCRIPTION("CRC32c (Castagnoli) optimization using Intel Hardware."); +MODULE_LICENSE("GPL"); + +MODULE_ALIAS("crc32c"); +MODULE_ALIAS("crc32c-intel"); |