/* * 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 * Kent Liu * * 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 #include #include #include #include #include #include #include #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 to account * for fpu state save/restore overhead. */ #define CRC32C_PCL_BREAKEVEN 512 asmlinkage unsigned int crc_pcl(const u8 *buffer, int len, unsigned int crc_init); #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 (boot_cpu_has(X86_FEATURE_PCLMULQDQ)) { alg.update = crc32c_pcl_intel_update; alg.finup = crc32c_pcl_intel_finup; alg.digest = crc32c_pcl_intel_digest; } #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 , Kent Liu "); MODULE_DESCRIPTION("CRC32c (Castagnoli) optimization using Intel Hardware."); MODULE_LICENSE("GPL"); MODULE_ALIAS_CRYPTO("crc32c"); MODULE_ALIAS_CRYPTO("crc32c-intel");