/*
   * Cryptographic API.
   *
   * Support for VIA PadLock hardware crypto engine.
   *
   * Copyright (c) 2006  Michal Ludvig <michal@logix.cz>
   *
   * 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 <crypto/internal/hash.h>

  #include <crypto/sha.h>

  #include <linux/err.h>

  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/errno.h>

  #include <linux/interrupt.h>
  #include <linux/kernel.h>
  #include <linux/scatterlist.h>

  #include <asm/i387.h>

  #include "padlock.h"

  #ifdef CONFIG_64BIT
  #define STACK_ALIGN 16
  #else
  #define STACK_ALIGN 4
  #endif

  struct padlock_sha_desc {
  	struct shash_desc fallback;

  };

  struct padlock_sha_ctx {
  	struct crypto_shash *fallback;
  };

  static int padlock_sha_init(struct shash_desc *desc)

  {

  	struct padlock_sha_desc *dctx = shash_desc_ctx(desc);
  	struct padlock_sha_ctx *ctx = crypto_shash_ctx(desc->tfm);

  	dctx->fallback.tfm = ctx->fallback;
  	dctx->fallback.flags = desc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
  	return crypto_shash_init(&dctx->fallback);

  }

  static int padlock_sha_update(struct shash_desc *desc,
  			      const u8 *data, unsigned int length)

  {

  	struct padlock_sha_desc *dctx = shash_desc_ctx(desc);

  	dctx->fallback.flags = desc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
  	return crypto_shash_update(&dctx->fallback, data, length);

  }

  static int padlock_sha_export(struct shash_desc *desc, void *out)
  {
  	struct padlock_sha_desc *dctx = shash_desc_ctx(desc);
  
  	return crypto_shash_export(&dctx->fallback, out);
  }
  
  static int padlock_sha_import(struct shash_desc *desc, const void *in)
  {
  	struct padlock_sha_desc *dctx = shash_desc_ctx(desc);
  	struct padlock_sha_ctx *ctx = crypto_shash_ctx(desc->tfm);
  
  	dctx->fallback.tfm = ctx->fallback;
  	dctx->fallback.flags = desc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
  	return crypto_shash_import(&dctx->fallback, in);
  }

  static inline void padlock_output_block(uint32_t *src,
  		 	uint32_t *dst, size_t count)
  {
  	while (count--)
  		*dst++ = swab32(*src++);
  }

  static int padlock_sha1_finup(struct shash_desc *desc, const u8 *in,
  			      unsigned int count, u8 *out)

  {
  	/* We can't store directly to *out as it may be unaligned. */
  	/* BTW Don't reduce the buffer size below 128 Bytes!
  	 *     PadLock microcode needs it that big. */

  	char buf[128 + PADLOCK_ALIGNMENT - STACK_ALIGN] __attribute__
  		((aligned(STACK_ALIGN)));
  	char *result = PTR_ALIGN(&buf[0], PADLOCK_ALIGNMENT);

  	struct padlock_sha_desc *dctx = shash_desc_ctx(desc);
  	struct sha1_state state;
  	unsigned int space;
  	unsigned int leftover;

  	int ts_state;

  	int err;
  
  	dctx->fallback.flags = desc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
  	err = crypto_shash_export(&dctx->fallback, &state);
  	if (err)
  		goto out;
  
  	if (state.count + count > ULONG_MAX)
  		return crypto_shash_finup(&dctx->fallback, in, count, out);
  
  	leftover = ((state.count - 1) & (SHA1_BLOCK_SIZE - 1)) + 1;
  	space =  SHA1_BLOCK_SIZE - leftover;
  	if (space) {
  		if (count > space) {
  			err = crypto_shash_update(&dctx->fallback, in, space) ?:
  			      crypto_shash_export(&dctx->fallback, &state);
  			if (err)
  				goto out;
  			count -= space;
  			in += space;
  		} else {
  			memcpy(state.buffer + leftover, in, count);
  			in = state.buffer;
  			count += leftover;

  			state.count &= ~(SHA1_BLOCK_SIZE - 1);

  		}
  	}
  
  	memcpy(result, &state.state, SHA1_DIGEST_SIZE);

  	/* prevent taking the spurious DNA fault with padlock. */
  	ts_state = irq_ts_save();

  	asm volatile (".byte 0xf3,0x0f,0xa6,0xc8" /* rep xsha1 */

  		      : \

  		      : "c"((unsigned long)state.count + count), \
  			"a"((unsigned long)state.count), \

  			"S"(in), "D"(result));

  	irq_ts_restore(ts_state);

  
  	padlock_output_block((uint32_t *)result, (uint32_t *)out, 5);

  
  out:
  	return err;

  }

  static int padlock_sha1_final(struct shash_desc *desc, u8 *out)
  {
  	u8 buf[4];
  
  	return padlock_sha1_finup(desc, buf, 0, out);
  }
  
  static int padlock_sha256_finup(struct shash_desc *desc, const u8 *in,
  				unsigned int count, u8 *out)

  {
  	/* We can't store directly to *out as it may be unaligned. */
  	/* BTW Don't reduce the buffer size below 128 Bytes!
  	 *     PadLock microcode needs it that big. */

  	char buf[128 + PADLOCK_ALIGNMENT - STACK_ALIGN] __attribute__
  		((aligned(STACK_ALIGN)));
  	char *result = PTR_ALIGN(&buf[0], PADLOCK_ALIGNMENT);

  	struct padlock_sha_desc *dctx = shash_desc_ctx(desc);
  	struct sha256_state state;
  	unsigned int space;
  	unsigned int leftover;

  	int ts_state;

  	int err;

  	dctx->fallback.flags = desc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
  	err = crypto_shash_export(&dctx->fallback, &state);
  	if (err)
  		goto out;
  
  	if (state.count + count > ULONG_MAX)
  		return crypto_shash_finup(&dctx->fallback, in, count, out);
  
  	leftover = ((state.count - 1) & (SHA256_BLOCK_SIZE - 1)) + 1;
  	space =  SHA256_BLOCK_SIZE - leftover;
  	if (space) {
  		if (count > space) {
  			err = crypto_shash_update(&dctx->fallback, in, space) ?:
  			      crypto_shash_export(&dctx->fallback, &state);
  			if (err)
  				goto out;
  			count -= space;
  			in += space;
  		} else {
  			memcpy(state.buf + leftover, in, count);
  			in = state.buf;
  			count += leftover;

  			state.count &= ~(SHA1_BLOCK_SIZE - 1);

  		}
  	}
  
  	memcpy(result, &state.state, SHA256_DIGEST_SIZE);

  	/* prevent taking the spurious DNA fault with padlock. */
  	ts_state = irq_ts_save();

  	asm volatile (".byte 0xf3,0x0f,0xa6,0xd0" /* rep xsha256 */

  		      : \

  		      : "c"((unsigned long)state.count + count), \
  			"a"((unsigned long)state.count), \

  			"S"(in), "D"(result));

  	irq_ts_restore(ts_state);

  
  	padlock_output_block((uint32_t *)result, (uint32_t *)out, 8);

  
  out:
  	return err;

  }

  static int padlock_sha256_final(struct shash_desc *desc, u8 *out)

  {

  	u8 buf[4];

  	return padlock_sha256_finup(desc, buf, 0, out);

  }

  static int padlock_cra_init(struct crypto_tfm *tfm)

  {

  	struct crypto_shash *hash = __crypto_shash_cast(tfm);

  	const char *fallback_driver_name = tfm->__crt_alg->cra_name;

  	struct padlock_sha_ctx *ctx = crypto_tfm_ctx(tfm);

  	struct crypto_shash *fallback_tfm;
  	int err = -ENOMEM;

  	/* Allocate a fallback and abort if it failed. */

  	fallback_tfm = crypto_alloc_shash(fallback_driver_name, 0,
  					  CRYPTO_ALG_NEED_FALLBACK);

  	if (IS_ERR(fallback_tfm)) {

  		printk(KERN_WARNING PFX "Fallback driver '%s' could not be loaded!
  ",
  		       fallback_driver_name);

  		err = PTR_ERR(fallback_tfm);

  		goto out;

  	}

  	ctx->fallback = fallback_tfm;
  	hash->descsize += crypto_shash_descsize(fallback_tfm);

  	return 0;

  out:
  	return err;

  }

  static void padlock_cra_exit(struct crypto_tfm *tfm)
  {

  	struct padlock_sha_ctx *ctx = crypto_tfm_ctx(tfm);

  	crypto_free_shash(ctx->fallback);

  }

  static struct shash_alg sha1_alg = {
  	.digestsize	=	SHA1_DIGEST_SIZE,
  	.init   	= 	padlock_sha_init,
  	.update 	=	padlock_sha_update,
  	.finup  	=	padlock_sha1_finup,
  	.final  	=	padlock_sha1_final,

  	.export		=	padlock_sha_export,
  	.import		=	padlock_sha_import,

  	.descsize	=	sizeof(struct padlock_sha_desc),

  	.statesize	=	sizeof(struct sha1_state),

  	.base		=	{
  		.cra_name		=	"sha1",
  		.cra_driver_name	=	"sha1-padlock",
  		.cra_priority		=	PADLOCK_CRA_PRIORITY,
  		.cra_flags		=	CRYPTO_ALG_TYPE_SHASH |
  						CRYPTO_ALG_NEED_FALLBACK,
  		.cra_blocksize		=	SHA1_BLOCK_SIZE,
  		.cra_ctxsize		=	sizeof(struct padlock_sha_ctx),
  		.cra_module		=	THIS_MODULE,
  		.cra_init		=	padlock_cra_init,
  		.cra_exit		=	padlock_cra_exit,

  	}
  };

  static struct shash_alg sha256_alg = {
  	.digestsize	=	SHA256_DIGEST_SIZE,
  	.init   	= 	padlock_sha_init,
  	.update 	=	padlock_sha_update,
  	.finup  	=	padlock_sha256_finup,
  	.final  	=	padlock_sha256_final,

  	.export		=	padlock_sha_export,
  	.import		=	padlock_sha_import,

  	.descsize	=	sizeof(struct padlock_sha_desc),

  	.statesize	=	sizeof(struct sha256_state),

  	.base		=	{
  		.cra_name		=	"sha256",
  		.cra_driver_name	=	"sha256-padlock",
  		.cra_priority		=	PADLOCK_CRA_PRIORITY,
  		.cra_flags		=	CRYPTO_ALG_TYPE_SHASH |
  						CRYPTO_ALG_NEED_FALLBACK,
  		.cra_blocksize		=	SHA256_BLOCK_SIZE,
  		.cra_ctxsize		=	sizeof(struct padlock_sha_ctx),
  		.cra_module		=	THIS_MODULE,
  		.cra_init		=	padlock_cra_init,
  		.cra_exit		=	padlock_cra_exit,

  	}
  };

  static int __init padlock_init(void)
  {
  	int rc = -ENODEV;
  
  	if (!cpu_has_phe) {

  		printk(KERN_NOTICE PFX "VIA PadLock Hash Engine not detected.
  ");

  		return -ENODEV;
  	}
  
  	if (!cpu_has_phe_enabled) {

  		printk(KERN_NOTICE PFX "VIA PadLock detected, but not enabled. Hmm, strange...
  ");

  		return -ENODEV;
  	}

  	rc = crypto_register_shash(&sha1_alg);

  	if (rc)
  		goto out;

  	rc = crypto_register_shash(&sha256_alg);

  	if (rc)
  		goto out_unreg1;
  
  	printk(KERN_NOTICE PFX "Using VIA PadLock ACE for SHA1/SHA256 algorithms.
  ");
  
  	return 0;
  
  out_unreg1:

  	crypto_unregister_shash(&sha1_alg);

  out:
  	printk(KERN_ERR PFX "VIA PadLock SHA1/SHA256 initialization failed.
  ");
  	return rc;
  }
  
  static void __exit padlock_fini(void)
  {

  	crypto_unregister_shash(&sha1_alg);
  	crypto_unregister_shash(&sha256_alg);

  }
  
  module_init(padlock_init);
  module_exit(padlock_fini);
  
  MODULE_DESCRIPTION("VIA PadLock SHA1/SHA256 algorithms support.");
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("Michal Ludvig");

  MODULE_ALIAS("sha1-all");
  MODULE_ALIAS("sha256-all");

  MODULE_ALIAS("sha1-padlock");
  MODULE_ALIAS("sha256-padlock");