text: /*
   * Accelerated GHASH implementation with Intel PCLMULQDQ-NI
   * instructions. This file contains glue code.
   *
   * Copyright (c) 2009 Intel Corp.
   *   Author: Huang Ying <ying.huang@intel.com>
   *
   * 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/err.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/kernel.h>
  #include <linux/crypto.h>
  #include <crypto/algapi.h>
  #include <crypto/cryptd.h>
  #include <crypto/gf128mul.h>
  #include <crypto/internal/hash.h>
  #include <asm/fpu/api.h>
  #include <asm/cpu_device_id.h>
  
  #define GHASH_BLOCK_SIZE	16
  #define GHASH_DIGEST_SIZE	16
  
  void clmul_ghash_mul(char *dst, const u128 *shash);
  
  void clmul_ghash_update(char *dst, const char *src, unsigned int srclen,
  			const u128 *shash);
  
  struct ghash_async_ctx {
  	struct cryptd_ahash *cryptd_tfm;
  };
  
  struct ghash_ctx {
  	u128 shash;
  };
  
  struct ghash_desc_ctx {
  	u8 buffer[GHASH_BLOCK_SIZE];
  	u32 bytes;
  };
  
  static int ghash_init(struct shash_desc *desc)
  {
  	struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
  
  	memset(dctx, 0, sizeof(*dctx));
  
  	return 0;
  }
  
  static int ghash_setkey(struct crypto_shash *tfm,
  			const u8 *key, unsigned int keylen)
  {
  	struct ghash_ctx *ctx = crypto_shash_ctx(tfm);
  	be128 *x = (be128 *)key;
  	u64 a, b;
  
  	if (keylen != GHASH_BLOCK_SIZE) {
  		crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
  		return -EINVAL;
  	}
  
  	/* perform multiplication by 'x' in GF(2^128) */
  	a = be64_to_cpu(x->a);
  	b = be64_to_cpu(x->b);
  
  	ctx->shash.a = (b << 1) | (a >> 63);
  	ctx->shash.b = (a << 1) | (b >> 63);
  
  	if (a >> 63)
  		ctx->shash.b ^= ((u64)0xc2) << 56;
  
  	return 0;
  }
  
  static int ghash_update(struct shash_desc *desc,
  			 const u8 *src, unsigned int srclen)
  {
  	struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
  	struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
  	u8 *dst = dctx->buffer;
  
  	kernel_fpu_begin();
  	if (dctx->bytes) {
  		int n = min(srclen, dctx->bytes);
  		u8 *pos = dst + (GHASH_BLOCK_SIZE - dctx->bytes);
  
  		dctx->bytes -= n;
  		srclen -= n;
  
  		while (n--)
  			*pos++ ^= *src++;
  
  		if (!dctx->bytes)
  			clmul_ghash_mul(dst, &ctx->shash);
  	}
  
  	clmul_ghash_update(dst, src, srclen, &ctx->shash);
  	kernel_fpu_end();
  
  	if (srclen & 0xf) {
  		src += srclen - (srclen & 0xf);
  		srclen &= 0xf;
  		dctx->bytes = GHASH_BLOCK_SIZE - srclen;
  		while (srclen--)
  			*dst++ ^= *src++;
  	}
  
  	return 0;
  }
  
  static void ghash_flush(struct ghash_ctx *ctx, struct ghash_desc_ctx *dctx)
  {
  	u8 *dst = dctx->buffer;
  
  	if (dctx->bytes) {
  		u8 *tmp = dst + (GHASH_BLOCK_SIZE - dctx->bytes);
  
  		while (dctx->bytes--)
  			*tmp++ ^= 0;
  
  		kernel_fpu_begin();
  		clmul_ghash_mul(dst, &ctx->shash);
  		kernel_fpu_end();
  	}
  
  	dctx->bytes = 0;
  }
  
  static int ghash_final(struct shash_desc *desc, u8 *dst)
  {
  	struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
  	struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
  	u8 *buf = dctx->buffer;
  
  	ghash_flush(ctx, dctx);
  	memcpy(dst, buf, GHASH_BLOCK_SIZE);
  
  	return 0;
  }
  
  static struct shash_alg ghash_alg = {
  	.digestsize	= GHASH_DIGEST_SIZE,
  	.init		= ghash_init,
  	.update		= ghash_update,
  	.final		= ghash_final,
  	.setkey		= ghash_setkey,
  	.descsize	= sizeof(struct ghash_desc_ctx),
  	.base		= {
  		.cra_name		= "__ghash",
  		.cra_driver_name	= "__ghash-pclmulqdqni",
  		.cra_priority		= 0,
  		.cra_flags		= CRYPTO_ALG_INTERNAL,
  		.cra_blocksize		= GHASH_BLOCK_SIZE,
  		.cra_ctxsize		= sizeof(struct ghash_ctx),
  		.cra_module		= THIS_MODULE,
  	},
  };
  
  static int ghash_async_init(struct ahash_request *req)
  {
  	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
  	struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
  	struct ahash_request *cryptd_req = ahash_request_ctx(req);
  	struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
  	struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
  	struct crypto_shash *child = cryptd_ahash_child(cryptd_tfm);
  
  	desc->tfm = child;
  	desc->flags = req->base.flags;
  	return crypto_shash_init(desc);
  }
  
  static int ghash_async_update(struct ahash_request *req)
  {
  	struct ahash_request *cryptd_req = ahash_request_ctx(req);
  	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
  	struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
  	struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
  
  	if (!irq_fpu_usable() ||
  	    (in_atomic() && cryptd_ahash_queued(cryptd_tfm))) {
  		memcpy(cryptd_req, req, sizeof(*req));
  		ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
  		return crypto_ahash_update(cryptd_req);
  	} else {
  		struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
  		return shash_ahash_update(req, desc);
  	}
  }
  
  static int ghash_async_final(struct ahash_request *req)
  {
  	struct ahash_request *cryptd_req = ahash_request_ctx(req);
  	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
  	struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
  	struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
  
  	if (!irq_fpu_usable() ||
  	    (in_atomic() && cryptd_ahash_queued(cryptd_tfm))) {
  		memcpy(cryptd_req, req, sizeof(*req));
  		ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
  		return crypto_ahash_final(cryptd_req);
  	} else {
  		struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
  		return crypto_shash_final(desc, req->result);
  	}
  }
  
  static int ghash_async_import(struct ahash_request *req, const void *in)
  {
  	struct ahash_request *cryptd_req = ahash_request_ctx(req);
  	struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
  	struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
  
  	ghash_async_init(req);
  	memcpy(dctx, in, sizeof(*dctx));
  	return 0;
  
  }
  
  static int ghash_async_export(struct ahash_request *req, void *out)
  {
  	struct ahash_request *cryptd_req = ahash_request_ctx(req);
  	struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
  	struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
  
  	memcpy(out, dctx, sizeof(*dctx));
  	return 0;
  
  }
  
  static int ghash_async_digest(struct ahash_request *req)
  {
  	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
  	struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
  	struct ahash_request *cryptd_req = ahash_request_ctx(req);
  	struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
  
  	if (!irq_fpu_usable() ||
  	    (in_atomic() && cryptd_ahash_queued(cryptd_tfm))) {
  		memcpy(cryptd_req, req, sizeof(*req));
  		ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
  		return crypto_ahash_digest(cryptd_req);
  	} else {
  		struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
  		struct crypto_shash *child = cryptd_ahash_child(cryptd_tfm);
  
  		desc->tfm = child;
  		desc->flags = req->base.flags;
  		return shash_ahash_digest(req, desc);
  	}
  }
  
  static int ghash_async_setkey(struct crypto_ahash *tfm, const u8 *key,
  			      unsigned int keylen)
  {
  	struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
  	struct crypto_ahash *child = &ctx->cryptd_tfm->base;
  	int err;
  
  	crypto_ahash_clear_flags(child, CRYPTO_TFM_REQ_MASK);
  	crypto_ahash_set_flags(child, crypto_ahash_get_flags(tfm)
  			       & CRYPTO_TFM_REQ_MASK);
  	err = crypto_ahash_setkey(child, key, keylen);
  	crypto_ahash_set_flags(tfm, crypto_ahash_get_flags(child)
  			       & CRYPTO_TFM_RES_MASK);
  
  	return err;
  }
  
  static int ghash_async_init_tfm(struct crypto_tfm *tfm)
  {
  	struct cryptd_ahash *cryptd_tfm;
  	struct ghash_async_ctx *ctx = crypto_tfm_ctx(tfm);
  
  	cryptd_tfm = cryptd_alloc_ahash("__ghash-pclmulqdqni",
  					CRYPTO_ALG_INTERNAL,
  					CRYPTO_ALG_INTERNAL);
  	if (IS_ERR(cryptd_tfm))
  		return PTR_ERR(cryptd_tfm);
  	ctx->cryptd_tfm = cryptd_tfm;
  	crypto_ahash_set_reqsize(__crypto_ahash_cast(tfm),
  				 sizeof(struct ahash_request) +
  				 crypto_ahash_reqsize(&cryptd_tfm->base));
  
  	return 0;
  }
  
  static void ghash_async_exit_tfm(struct crypto_tfm *tfm)
  {
  	struct ghash_async_ctx *ctx = crypto_tfm_ctx(tfm);
  
  	cryptd_free_ahash(ctx->cryptd_tfm);
  }
  
  static struct ahash_alg ghash_async_alg = {
  	.init		= ghash_async_init,
  	.update		= ghash_async_update,
  	.final		= ghash_async_final,
  	.setkey		= ghash_async_setkey,
  	.digest		= ghash_async_digest,
  	.export		= ghash_async_export,
  	.import		= ghash_async_import,
  	.halg = {
  		.digestsize	= GHASH_DIGEST_SIZE,
  		.statesize = sizeof(struct ghash_desc_ctx),
  		.base = {
  			.cra_name		= "ghash",
  			.cra_driver_name	= "ghash-clmulni",
  			.cra_priority		= 400,
  			.cra_ctxsize		= sizeof(struct ghash_async_ctx),
  			.cra_flags		= CRYPTO_ALG_ASYNC,
  			.cra_blocksize		= GHASH_BLOCK_SIZE,
  			.cra_module		= THIS_MODULE,
  			.cra_init		= ghash_async_init_tfm,
  			.cra_exit		= ghash_async_exit_tfm,
  		},
  	},
  };
  
  static const struct x86_cpu_id pcmul_cpu_id[] = {
  	X86_FEATURE_MATCH(X86_FEATURE_PCLMULQDQ), /* Pickle-Mickle-Duck */
  	{}
  };
  MODULE_DEVICE_TABLE(x86cpu, pcmul_cpu_id);
  
  static int __init ghash_pclmulqdqni_mod_init(void)
  {
  	int err;
  
  	if (!x86_match_cpu(pcmul_cpu_id))
  		return -ENODEV;
  
  	err = crypto_register_shash(&ghash_alg);
  	if (err)
  		goto err_out;
  	err = crypto_register_ahash(&ghash_async_alg);
  	if (err)
  		goto err_shash;
  
  	return 0;
  
  err_shash:
  	crypto_unregister_shash(&ghash_alg);
  err_out:
  	return err;
  }
  
  static void __exit ghash_pclmulqdqni_mod_exit(void)
  {
  	crypto_unregister_ahash(&ghash_async_alg);
  	crypto_unregister_shash(&ghash_alg);
  }
  
  module_init(ghash_pclmulqdqni_mod_init);
  module_exit(ghash_pclmulqdqni_mod_exit);
  
  MODULE_LICENSE("GPL");
  MODULE_DESCRIPTION("GHASH Message Digest Algorithm, "
  		   "accelerated by PCLMULQDQ-NI");
  MODULE_ALIAS_CRYPTO("ghash");
  