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-rw-r--r--arch/x86/crypto/crc32c-intel.c197
1 files changed, 197 insertions, 0 deletions
diff --git a/arch/x86/crypto/crc32c-intel.c b/arch/x86/crypto/crc32c-intel.c
new file mode 100644
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+++ b/arch/x86/crypto/crc32c-intel.c
@@ -0,0 +1,197 @@
+/*
+ * 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 Austin Zhang <austin_zhang@linux.intel.com>
+ * Copyright (c) 2008 Kent Liu <kent.liu@intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ */
+#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>
+
+#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
+
+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_ahash *hash, const u8 *key,
+ unsigned int keylen)
+{
+ u32 *mctx = crypto_ahash_ctx(hash);
+
+ if (keylen != sizeof(u32)) {
+ crypto_ahash_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 ahash_request *req)
+{
+ u32 *mctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
+ u32 *crcp = ahash_request_ctx(req);
+
+ *crcp = *mctx;
+
+ return 0;
+}
+
+static int crc32c_intel_update(struct ahash_request *req)
+{
+ struct crypto_hash_walk walk;
+ u32 *crcp = ahash_request_ctx(req);
+ u32 crc = *crcp;
+ int nbytes;
+
+ for (nbytes = crypto_hash_walk_first(req, &walk); nbytes;
+ nbytes = crypto_hash_walk_done(&walk, 0))
+ crc = crc32c_intel_le_hw(crc, walk.data, nbytes);
+
+ *crcp = crc;
+ return 0;
+}
+
+static int crc32c_intel_final(struct ahash_request *req)
+{
+ u32 *crcp = ahash_request_ctx(req);
+
+ *(__le32 *)req->result = ~cpu_to_le32p(crcp);
+ return 0;
+}
+
+static int crc32c_intel_digest(struct ahash_request *req)
+{
+ struct crypto_hash_walk walk;
+ u32 *mctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
+ u32 crc = *mctx;
+ int nbytes;
+
+ for (nbytes = crypto_hash_walk_first(req, &walk); nbytes;
+ nbytes = crypto_hash_walk_done(&walk, 0))
+ crc = crc32c_intel_le_hw(crc, walk.data, nbytes);
+
+ *(__le32 *)req->result = ~cpu_to_le32(crc);
+ return 0;
+}
+
+static int crc32c_intel_cra_init(struct crypto_tfm *tfm)
+{
+ u32 *key = crypto_tfm_ctx(tfm);
+
+ *key = ~0;
+
+ tfm->crt_ahash.reqsize = sizeof(u32);
+
+ return 0;
+}
+
+static struct crypto_alg alg = {
+ .cra_name = "crc32c",
+ .cra_driver_name = "crc32c-intel",
+ .cra_priority = 200,
+ .cra_flags = CRYPTO_ALG_TYPE_AHASH,
+ .cra_blocksize = CHKSUM_BLOCK_SIZE,
+ .cra_alignmask = 3,
+ .cra_ctxsize = sizeof(u32),
+ .cra_module = THIS_MODULE,
+ .cra_list = LIST_HEAD_INIT(alg.cra_list),
+ .cra_init = crc32c_intel_cra_init,
+ .cra_type = &crypto_ahash_type,
+ .cra_u = {
+ .ahash = {
+ .digestsize = CHKSUM_DIGEST_SIZE,
+ .setkey = crc32c_intel_setkey,
+ .init = crc32c_intel_init,
+ .update = crc32c_intel_update,
+ .final = crc32c_intel_final,
+ .digest = crc32c_intel_digest,
+ }
+ }
+};
+
+
+static int __init crc32c_intel_mod_init(void)
+{
+ if (cpu_has_xmm4_2)
+ return crypto_register_alg(&alg);
+ else
+ return -ENODEV;
+}
+
+static void __exit crc32c_intel_mod_fini(void)
+{
+ crypto_unregister_alg(&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");
+
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