crypto: ghash - Add PCLMULQDQ accelerated implementation

PCLMULQDQ is used to accelerate the most time-consuming part of GHASH,
carry-less multiplication. More information about PCLMULQDQ can be
found at:

http://software.intel.com/en-us/articles/carry-less-multiplication-and-its-usage-for-computing-the-gcm-mode/

Because PCLMULQDQ changes XMM state, its usage must be enclosed with
kernel_fpu_begin/end, which can be used only in process context, the
acceleration is implemented as crypto_ahash. That is, request in soft
IRQ context will be defered to the cryptd kernel thread.

Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 333 insertions, 0 deletions

diff --git a/arch/x86/crypto/ghash-clmulni-intel_glue.c b/arch/x86/crypto/ghash-clmulni-intel_glue.c
new file mode 100644
index 0000000..65d4096
--- /dev/null
+++ b/arch/x86/crypto/ghash-clmulni-intel_glue.c
@@ -0,0 +1,333 @@
+/*
+ * 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/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/i387.h>
+
+#define GHASH_BLOCK_SIZE	16
+#define GHASH_DIGEST_SIZE	16
+
+void clmul_ghash_mul(char *dst, const be128 *shash);
+
+void clmul_ghash_update(char *dst, const char *src, unsigned int srclen,
+			const be128 *shash);
+
+void clmul_ghash_setkey(be128 *shash, const u8 *key);
+
+struct ghash_async_ctx {
+	struct cryptd_ahash *cryptd_tfm;
+};
+
+struct ghash_ctx {
+	be128 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);
+
+	if (keylen != GHASH_BLOCK_SIZE) {
+		crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
+		return -EINVAL;
+	}
+
+	clmul_ghash_setkey(&ctx->shash, key);
+
+	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_TYPE_SHASH,
+		.cra_blocksize		= GHASH_BLOCK_SIZE,
+		.cra_ctxsize		= sizeof(struct ghash_ctx),
+		.cra_module		= THIS_MODULE,
+		.cra_list		= LIST_HEAD_INIT(ghash_alg.base.cra_list),
+	},
+};
+
+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;
+
+	if (irq_fpu_usable()) {
+		memcpy(cryptd_req, req, sizeof(*req));
+		ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
+		return crypto_ahash_init(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 crypto_shash_init(desc);
+	}
+}
+
+static int ghash_async_update(struct ahash_request *req)
+{
+	struct ahash_request *cryptd_req = ahash_request_ctx(req);
+
+	if (irq_fpu_usable()) {
+		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;
+
+		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);
+
+	if (irq_fpu_usable()) {
+		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;
+
+		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_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()) {
+		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 0;
+}
+
+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", 0, 0);
+	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,
+	.halg = {
+		.digestsize	= GHASH_DIGEST_SIZE,
+		.base = {
+			.cra_name		= "ghash",
+			.cra_driver_name	= "ghash-clmulni",
+			.cra_priority		= 400,
+			.cra_flags		= CRYPTO_ALG_TYPE_AHASH | CRYPTO_ALG_ASYNC,
+			.cra_blocksize		= GHASH_BLOCK_SIZE,
+			.cra_type		= &crypto_ahash_type,
+			.cra_module		= THIS_MODULE,
+			.cra_list		= LIST_HEAD_INIT(ghash_async_alg.halg.base.cra_list),
+			.cra_init		= ghash_async_init_tfm,
+			.cra_exit		= ghash_async_exit_tfm,
+		},
+	},
+};
+
+static int __init ghash_pclmulqdqni_mod_init(void)
+{
+	int err;
+
+	if (!cpu_has_pclmulqdq) {
+		printk(KERN_INFO "Intel PCLMULQDQ-NI instructions are not"
+		       " detected.\n");
+		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, "
+		   "acclerated by PCLMULQDQ-NI");
+MODULE_ALIAS("ghash");