text: /*
   * Cryptographic API.
   *
   * Glue code for the SHA512 Secure Hash Algorithm assembler
   * implementation using supplemental SSE3 / AVX / AVX2 instructions.
   *
   * This file is based on sha512_generic.c
   *
   * Copyright (C) 2013 Intel Corporation
   * Author: Tim Chen <tim.c.chen@linux.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.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
   * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
   * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
   * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
   * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   *
   */
  
  #define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
  
  #include <crypto/internal/hash.h>
  #include <linux/init.h>
  #include <linux/module.h>
  #include <linux/mm.h>
  #include <linux/cryptohash.h>
  #include <linux/types.h>
  #include <crypto/sha.h>
  #include <asm/byteorder.h>
  #include <asm/i387.h>
  #include <asm/xcr.h>
  #include <asm/xsave.h>
  
  #include <linux/string.h>
  
  asmlinkage void sha512_transform_ssse3(const char *data, u64 *digest,
  				     u64 rounds);
  #ifdef CONFIG_AS_AVX
  asmlinkage void sha512_transform_avx(const char *data, u64 *digest,
  				     u64 rounds);
  #endif
  #ifdef CONFIG_AS_AVX2
  asmlinkage void sha512_transform_rorx(const char *data, u64 *digest,
  				     u64 rounds);
  #endif
  
  static asmlinkage void (*sha512_transform_asm)(const char *, u64 *, u64);
  
  
  static int sha512_ssse3_init(struct shash_desc *desc)
  {
  	struct sha512_state *sctx = shash_desc_ctx(desc);
  
  	sctx->state[0] = SHA512_H0;
  	sctx->state[1] = SHA512_H1;
  	sctx->state[2] = SHA512_H2;
  	sctx->state[3] = SHA512_H3;
  	sctx->state[4] = SHA512_H4;
  	sctx->state[5] = SHA512_H5;
  	sctx->state[6] = SHA512_H6;
  	sctx->state[7] = SHA512_H7;
  	sctx->count[0] = sctx->count[1] = 0;
  
  	return 0;
  }
  
  static int __sha512_ssse3_update(struct shash_desc *desc, const u8 *data,
  			       unsigned int len, unsigned int partial)
  {
  	struct sha512_state *sctx = shash_desc_ctx(desc);
  	unsigned int done = 0;
  
  	sctx->count[0] += len;
  	if (sctx->count[0] < len)
  		sctx->count[1]++;
  
  	if (partial) {
  		done = SHA512_BLOCK_SIZE - partial;
  		memcpy(sctx->buf + partial, data, done);
  		sha512_transform_asm(sctx->buf, sctx->state, 1);
  	}
  
  	if (len - done >= SHA512_BLOCK_SIZE) {
  		const unsigned int rounds = (len - done) / SHA512_BLOCK_SIZE;
  
  		sha512_transform_asm(data + done, sctx->state, (u64) rounds);
  
  		done += rounds * SHA512_BLOCK_SIZE;
  	}
  
  	memcpy(sctx->buf, data + done, len - done);
  
  	return 0;
  }
  
  static int sha512_ssse3_update(struct shash_desc *desc, const u8 *data,
  			     unsigned int len)
  {
  	struct sha512_state *sctx = shash_desc_ctx(desc);
  	unsigned int partial = sctx->count[0] % SHA512_BLOCK_SIZE;
  	int res;
  
  	/* Handle the fast case right here */
  	if (partial + len < SHA512_BLOCK_SIZE) {
  		sctx->count[0] += len;
  		if (sctx->count[0] < len)
  			sctx->count[1]++;
  		memcpy(sctx->buf + partial, data, len);
  
  		return 0;
  	}
  
  	if (!irq_fpu_usable()) {
  		res = crypto_sha512_update(desc, data, len);
  	} else {
  		kernel_fpu_begin();
  		res = __sha512_ssse3_update(desc, data, len, partial);
  		kernel_fpu_end();
  	}
  
  	return res;
  }
  
  
  /* Add padding and return the message digest. */
  static int sha512_ssse3_final(struct shash_desc *desc, u8 *out)
  {
  	struct sha512_state *sctx = shash_desc_ctx(desc);
  	unsigned int i, index, padlen;
  	__be64 *dst = (__be64 *)out;
  	__be64 bits[2];
  	static const u8 padding[SHA512_BLOCK_SIZE] = { 0x80, };
  
  	/* save number of bits */
  	bits[1] = cpu_to_be64(sctx->count[0] << 3);
  	bits[0] = cpu_to_be64(sctx->count[1] << 3 | sctx->count[0] >> 61);
  
  	/* Pad out to 112 mod 128 and append length */
  	index = sctx->count[0] & 0x7f;
  	padlen = (index < 112) ? (112 - index) : ((128+112) - index);
  
  	if (!irq_fpu_usable()) {
  		crypto_sha512_update(desc, padding, padlen);
  		crypto_sha512_update(desc, (const u8 *)&bits, sizeof(bits));
  	} else {
  		kernel_fpu_begin();
  		/* We need to fill a whole block for __sha512_ssse3_update() */
  		if (padlen <= 112) {
  			sctx->count[0] += padlen;
  			if (sctx->count[0] < padlen)
  				sctx->count[1]++;
  			memcpy(sctx->buf + index, padding, padlen);
  		} else {
  			__sha512_ssse3_update(desc, padding, padlen, index);
  		}
  		__sha512_ssse3_update(desc, (const u8 *)&bits,
  					sizeof(bits), 112);
  		kernel_fpu_end();
  	}
  
  	/* Store state in digest */
  	for (i = 0; i < 8; i++)
  		dst[i] = cpu_to_be64(sctx->state[i]);
  
  	/* Wipe context */
  	memset(sctx, 0, sizeof(*sctx));
  
  	return 0;
  }
  
  static int sha512_ssse3_export(struct shash_desc *desc, void *out)
  {
  	struct sha512_state *sctx = shash_desc_ctx(desc);
  
  	memcpy(out, sctx, sizeof(*sctx));
  
  	return 0;
  }
  
  static int sha512_ssse3_import(struct shash_desc *desc, const void *in)
  {
  	struct sha512_state *sctx = shash_desc_ctx(desc);
  
  	memcpy(sctx, in, sizeof(*sctx));
  
  	return 0;
  }
  
  static struct shash_alg alg = {
  	.digestsize	=	SHA512_DIGEST_SIZE,
  	.init		=	sha512_ssse3_init,
  	.update		=	sha512_ssse3_update,
  	.final		=	sha512_ssse3_final,
  	.export		=	sha512_ssse3_export,
  	.import		=	sha512_ssse3_import,
  	.descsize	=	sizeof(struct sha512_state),
  	.statesize	=	sizeof(struct sha512_state),
  	.base		=	{
  		.cra_name	=	"sha512",
  		.cra_driver_name =	"sha512-ssse3",
  		.cra_priority	=	150,
  		.cra_flags	=	CRYPTO_ALG_TYPE_SHASH,
  		.cra_blocksize	=	SHA512_BLOCK_SIZE,
  		.cra_module	=	THIS_MODULE,
  	}
  };
  
  #ifdef CONFIG_AS_AVX
  static bool __init avx_usable(void)
  {
  	u64 xcr0;
  
  	if (!cpu_has_avx || !cpu_has_osxsave)
  		return false;
  
  	xcr0 = xgetbv(XCR_XFEATURE_ENABLED_MASK);
  	if ((xcr0 & (XSTATE_SSE | XSTATE_YMM)) != (XSTATE_SSE | XSTATE_YMM)) {
  		pr_info("AVX detected but unusable.\n");
  
  		return false;
  	}
  
  	return true;
  }
  #endif
  
  static int __init sha512_ssse3_mod_init(void)
  {
  	/* test for SSE3 first */
  	if (cpu_has_ssse3)
  		sha512_transform_asm = sha512_transform_ssse3;
  
  #ifdef CONFIG_AS_AVX
  	/* allow AVX to override SSSE3, it's a little faster */
  	if (avx_usable()) {
  #ifdef CONFIG_AS_AVX2
  		if (boot_cpu_has(X86_FEATURE_AVX2))
  			sha512_transform_asm = sha512_transform_rorx;
  		else
  #endif
  			sha512_transform_asm = sha512_transform_avx;
  	}
  #endif
  
  	if (sha512_transform_asm) {
  #ifdef CONFIG_AS_AVX
  		if (sha512_transform_asm == sha512_transform_avx)
  			pr_info("Using AVX optimized SHA-512 implementation\n");
  #ifdef CONFIG_AS_AVX2
  		else if (sha512_transform_asm == sha512_transform_rorx)
  			pr_info("Using AVX2 optimized SHA-512 implementation\n");
  #endif
  		else
  #endif
  			pr_info("Using SSSE3 optimized SHA-512 implementation\n");
  		return crypto_register_shash(&alg);
  	}
  	pr_info("Neither AVX nor SSSE3 is available/usable.\n");
  
  	return -ENODEV;
  }
  
  static void __exit sha512_ssse3_mod_fini(void)
  {
  	crypto_unregister_shash(&alg);
  }
  
  module_init(sha512_ssse3_mod_init);
  module_exit(sha512_ssse3_mod_fini);
  
  MODULE_LICENSE("GPL");
  MODULE_DESCRIPTION("SHA512 Secure Hash Algorithm, Supplemental SSE3 accelerated");
  
  MODULE_ALIAS_CRYPTO("sha512");
  