/*
   * 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/padlock.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/cpu_device_id.h>
  #include <asm/i387.h>
  
  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,
  	}
  };
  
  /* Add two shash_alg instance for hardware-implemented *
  * multiple-parts hash supported by VIA Nano Processor.*/
  static int padlock_sha1_init_nano(struct shash_desc *desc)
  {
  	struct sha1_state *sctx = shash_desc_ctx(desc);
  
  	*sctx = (struct sha1_state){
  		.state = { SHA1_H0, SHA1_H1, SHA1_H2, SHA1_H3, SHA1_H4 },
  	};
  
  	return 0;
  }
  
  static int padlock_sha1_update_nano(struct shash_desc *desc,
  			const u8 *data,	unsigned int len)
  {
  	struct sha1_state *sctx = shash_desc_ctx(desc);
  	unsigned int partial, done;
  	const u8 *src;
  	/*The PHE require the out buffer must 128 bytes and 16-bytes aligned*/
  	u8 buf[128 + PADLOCK_ALIGNMENT - STACK_ALIGN] __attribute__
  		((aligned(STACK_ALIGN)));
  	u8 *dst = PTR_ALIGN(&buf[0], PADLOCK_ALIGNMENT);
  	int ts_state;
  
  	partial = sctx->count & 0x3f;
  	sctx->count += len;
  	done = 0;
  	src = data;
  	memcpy(dst, (u8 *)(sctx->state), SHA1_DIGEST_SIZE);
  
  	if ((partial + len) >= SHA1_BLOCK_SIZE) {
  
  		/* Append the bytes in state's buffer to a block to handle */
  		if (partial) {
  			done = -partial;
  			memcpy(sctx->buffer + partial, data,
  				done + SHA1_BLOCK_SIZE);
  			src = sctx->buffer;
  			ts_state = irq_ts_save();
  			asm volatile (".byte 0xf3,0x0f,0xa6,0xc8"
  			: "+S"(src), "+D"(dst) \
  			: "a"((long)-1), "c"((unsigned long)1));
  			irq_ts_restore(ts_state);
  			done += SHA1_BLOCK_SIZE;
  			src = data + done;
  		}
  
  		/* Process the left bytes from the input data */
  		if (len - done >= SHA1_BLOCK_SIZE) {
  			ts_state = irq_ts_save();
  			asm volatile (".byte 0xf3,0x0f,0xa6,0xc8"
  			: "+S"(src), "+D"(dst)
  			: "a"((long)-1),
  			"c"((unsigned long)((len - done) / SHA1_BLOCK_SIZE)));
  			irq_ts_restore(ts_state);
  			done += ((len - done) - (len - done) % SHA1_BLOCK_SIZE);
  			src = data + done;
  		}
  		partial = 0;
  	}
  	memcpy((u8 *)(sctx->state), dst, SHA1_DIGEST_SIZE);
  	memcpy(sctx->buffer + partial, src, len - done);
  
  	return 0;
  }
  
  static int padlock_sha1_final_nano(struct shash_desc *desc, u8 *out)
  {
  	struct sha1_state *state = (struct sha1_state *)shash_desc_ctx(desc);
  	unsigned int partial, padlen;
  	__be64 bits;
  	static const u8 padding[64] = { 0x80, };
  
  	bits = cpu_to_be64(state->count << 3);
  
  	/* Pad out to 56 mod 64 */
  	partial = state->count & 0x3f;
  	padlen = (partial < 56) ? (56 - partial) : ((64+56) - partial);
  	padlock_sha1_update_nano(desc, padding, padlen);
  
  	/* Append length field bytes */
  	padlock_sha1_update_nano(desc, (const u8 *)&bits, sizeof(bits));
  
  	/* Swap to output */
  	padlock_output_block((uint32_t *)(state->state), (uint32_t *)out, 5);
  
  	return 0;
  }
  
  static int padlock_sha256_init_nano(struct shash_desc *desc)
  {
  	struct sha256_state *sctx = shash_desc_ctx(desc);
  
  	*sctx = (struct sha256_state){
  		.state = { SHA256_H0, SHA256_H1, SHA256_H2, SHA256_H3, \
  				SHA256_H4, SHA256_H5, SHA256_H6, SHA256_H7},
  	};
  
  	return 0;
  }
  
  static int padlock_sha256_update_nano(struct shash_desc *desc, const u8 *data,
  			  unsigned int len)
  {
  	struct sha256_state *sctx = shash_desc_ctx(desc);
  	unsigned int partial, done;
  	const u8 *src;
  	/*The PHE require the out buffer must 128 bytes and 16-bytes aligned*/
  	u8 buf[128 + PADLOCK_ALIGNMENT - STACK_ALIGN] __attribute__
  		((aligned(STACK_ALIGN)));
  	u8 *dst = PTR_ALIGN(&buf[0], PADLOCK_ALIGNMENT);
  	int ts_state;
  
  	partial = sctx->count & 0x3f;
  	sctx->count += len;
  	done = 0;
  	src = data;
  	memcpy(dst, (u8 *)(sctx->state), SHA256_DIGEST_SIZE);
  
  	if ((partial + len) >= SHA256_BLOCK_SIZE) {
  
  		/* Append the bytes in state's buffer to a block to handle */
  		if (partial) {
  			done = -partial;
  			memcpy(sctx->buf + partial, data,
  				done + SHA256_BLOCK_SIZE);
  			src = sctx->buf;
  			ts_state = irq_ts_save();
  			asm volatile (".byte 0xf3,0x0f,0xa6,0xd0"
  			: "+S"(src), "+D"(dst)
  			: "a"((long)-1), "c"((unsigned long)1));
  			irq_ts_restore(ts_state);
  			done += SHA256_BLOCK_SIZE;
  			src = data + done;
  		}
  
  		/* Process the left bytes from input data*/
  		if (len - done >= SHA256_BLOCK_SIZE) {
  			ts_state = irq_ts_save();
  			asm volatile (".byte 0xf3,0x0f,0xa6,0xd0"
  			: "+S"(src), "+D"(dst)
  			: "a"((long)-1),
  			"c"((unsigned long)((len - done) / 64)));
  			irq_ts_restore(ts_state);
  			done += ((len - done) - (len - done) % 64);
  			src = data + done;
  		}
  		partial = 0;
  	}
  	memcpy((u8 *)(sctx->state), dst, SHA256_DIGEST_SIZE);
  	memcpy(sctx->buf + partial, src, len - done);
  
  	return 0;
  }
  
  static int padlock_sha256_final_nano(struct shash_desc *desc, u8 *out)
  {
  	struct sha256_state *state =
  		(struct sha256_state *)shash_desc_ctx(desc);
  	unsigned int partial, padlen;
  	__be64 bits;
  	static const u8 padding[64] = { 0x80, };
  
  	bits = cpu_to_be64(state->count << 3);
  
  	/* Pad out to 56 mod 64 */
  	partial = state->count & 0x3f;
  	padlen = (partial < 56) ? (56 - partial) : ((64+56) - partial);
  	padlock_sha256_update_nano(desc, padding, padlen);
  
  	/* Append length field bytes */
  	padlock_sha256_update_nano(desc, (const u8 *)&bits, sizeof(bits));
  
  	/* Swap to output */
  	padlock_output_block((uint32_t *)(state->state), (uint32_t *)out, 8);
  
  	return 0;
  }
  
  static int padlock_sha_export_nano(struct shash_desc *desc,
  				void *out)
  {
  	int statesize = crypto_shash_statesize(desc->tfm);
  	void *sctx = shash_desc_ctx(desc);
  
  	memcpy(out, sctx, statesize);
  	return 0;
  }
  
  static int padlock_sha_import_nano(struct shash_desc *desc,
  				const void *in)
  {
  	int statesize = crypto_shash_statesize(desc->tfm);
  	void *sctx = shash_desc_ctx(desc);
  
  	memcpy(sctx, in, statesize);
  	return 0;
  }
  
  static struct shash_alg sha1_alg_nano = {
  	.digestsize	=	SHA1_DIGEST_SIZE,
  	.init		=	padlock_sha1_init_nano,
  	.update		=	padlock_sha1_update_nano,
  	.final		=	padlock_sha1_final_nano,
  	.export		=	padlock_sha_export_nano,
  	.import		=	padlock_sha_import_nano,
  	.descsize	=	sizeof(struct sha1_state),
  	.statesize	=	sizeof(struct sha1_state),
  	.base		=	{
  		.cra_name		=	"sha1",
  		.cra_driver_name	=	"sha1-padlock-nano",
  		.cra_priority		=	PADLOCK_CRA_PRIORITY,
  		.cra_flags		=	CRYPTO_ALG_TYPE_SHASH,
  		.cra_blocksize		=	SHA1_BLOCK_SIZE,
  		.cra_module		=	THIS_MODULE,
  	}
  };
  
  static struct shash_alg sha256_alg_nano = {
  	.digestsize	=	SHA256_DIGEST_SIZE,
  	.init		=	padlock_sha256_init_nano,
  	.update		=	padlock_sha256_update_nano,
  	.final		=	padlock_sha256_final_nano,
  	.export		=	padlock_sha_export_nano,
  	.import		=	padlock_sha_import_nano,
  	.descsize	=	sizeof(struct sha256_state),
  	.statesize	=	sizeof(struct sha256_state),
  	.base		=	{
  		.cra_name		=	"sha256",
  		.cra_driver_name	=	"sha256-padlock-nano",
  		.cra_priority		=	PADLOCK_CRA_PRIORITY,
  		.cra_flags		=	CRYPTO_ALG_TYPE_SHASH,
  		.cra_blocksize		=	SHA256_BLOCK_SIZE,
  		.cra_module		=	THIS_MODULE,
  	}
  };
  
  static struct x86_cpu_id padlock_sha_ids[] = {
  	X86_FEATURE_MATCH(X86_FEATURE_PHE),
  	{}
  };
  MODULE_DEVICE_TABLE(x86cpu, padlock_sha_ids);
  
  static int __init padlock_init(void)
  {
  	int rc = -ENODEV;
  	struct cpuinfo_x86 *c = &cpu_data(0);
  	struct shash_alg *sha1;
  	struct shash_alg *sha256;
  
  	if (!x86_match_cpu(padlock_sha_ids) || !cpu_has_phe_enabled)
  		return -ENODEV;
  
  	/* Register the newly added algorithm module if on *
  	* VIA Nano processor, or else just do as before */
  	if (c->x86_model < 0x0f) {
  		sha1 = &sha1_alg;
  		sha256 = &sha256_alg;
  	} else {
  		sha1 = &sha1_alg_nano;
  		sha256 = &sha256_alg_nano;
  	}
  
  	rc = crypto_register_shash(sha1);
  	if (rc)
  		goto out;
  
  	rc = crypto_register_shash(sha256);
  	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);
  
  out:
  	printk(KERN_ERR PFX "VIA PadLock SHA1/SHA256 initialization failed.
  ");
  	return rc;
  }
  
  static void __exit padlock_fini(void)
  {
  	struct cpuinfo_x86 *c = &cpu_data(0);
  
  	if (c->x86_model >= 0x0f) {
  		crypto_unregister_shash(&sha1_alg_nano);
  		crypto_unregister_shash(&sha256_alg_nano);
  	} else {
  		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");