crypto/arm: add support for GHASH using ARMv8 Crypto Extensions

diff --git a/arch/arm/crypto/Kconfig b/arch/arm/crypto/Kconfig
index 63588bdf3b5d..5dc8a9e79744 100644
--- a/arch/arm/crypto/Kconfig
+++ b/arch/arm/crypto/Kconfig
@@ -110,4 +110,13 @@  config CRYPTO_AES_ARM_CE
 	  Use an implementation of AES in CBC, CTR and XTS modes that uses
 	  ARMv8 Crypto Extensions
 
+config CRYPTO_GHASH_ARM_CE
+	tristate "PMULL-accelerated GHASH using ARMv8 Crypto Extensions"
+	depends on KERNEL_MODE_NEON
+	select CRYPTO_HASH
+	help
+	  Use an implementation of GHASH (used by the GCM AEAD chaining mode)
+	  that uses the 64x64 to 128 bit polynomial multiplication (vmull.p64)
+	  that is part of the ARMv8 Crypto Extensions
+
 endif
diff --git a/arch/arm/crypto/Makefile b/arch/arm/crypto/Makefile
index 2514c420e8d3..9a273bd7dffd 100644
--- a/arch/arm/crypto/Makefile
+++ b/arch/arm/crypto/Makefile
@@ -10,6 +10,7 @@  obj-$(CONFIG_CRYPTO_SHA1_ARM_NEON) += sha1-arm-neon.o
 obj-$(CONFIG_CRYPTO_SHA512_ARM_NEON) += sha512-arm-neon.o
 obj-$(CONFIG_CRYPTO_SHA1_ARM_CE) += sha1-arm-ce.o
 obj-$(CONFIG_CRYPTO_SHA2_ARM_CE) += sha2-arm-ce.o
+obj-$(CONFIG_CRYPTO_GHASH_ARM_CE) += ghash-arm-ce.o
 
 aes-arm-y	:= aes-armv4.o aes_glue.o
 aes-arm-bs-y	:= aesbs-core.o aesbs-glue.o
@@ -19,6 +20,7 @@  sha512-arm-neon-y := sha512-armv7-neon.o sha512_neon_glue.o
 sha1-arm-ce-y	:= sha1-ce-core.o sha1-ce-glue.o
 sha2-arm-ce-y	:= sha2-ce-core.o sha2-ce-glue.o
 aes-arm-ce-y	:= aes-ce-core.o aes-ce-glue.o
+ghash-arm-ce-y	:= ghash-ce-core.o ghash-ce-glue.o
 
 quiet_cmd_perl = PERL    $@
       cmd_perl = $(PERL) $(<) > $(@)
diff --git a/arch/arm/crypto/ghash-ce-core.S b/arch/arm/crypto/ghash-ce-core.S
new file mode 100644
index 000000000000..53bee60ff94b
--- /dev/null
+++ b/arch/arm/crypto/ghash-ce-core.S
@@ -0,0 +1,93 @@ 
+/*
+ * Accelerated GHASH implementation with ARMv8 vmull.p64 instructions.
+ *
+ * Copyright (C) 2015 Linaro Ltd. <ard.biesheuvel@linaro.org>
+ *
+ * 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/linkage.h>
+#include <asm/assembler.h>
+
+	SHASH		.req	q0
+	SHASH2		.req	q1
+	T1		.req	q2
+	T2		.req	q3
+	MASK		.req	q4
+	XL		.req	q5
+	XM		.req	q6
+	XH		.req	q7
+	IN1		.req	q7
+
+	SHASH_L		.req	d0
+	SHASH_H		.req	d1
+	SHASH2_L	.req	d2
+	T1_L		.req	d4
+	MASK_L		.req	d8
+	XL_L		.req	d10
+	XL_H		.req	d11
+	XM_L		.req	d12
+	XM_H		.req	d13
+	XH_L		.req	d14
+
+	.text
+	.fpu		crypto-neon-fp-armv8
+
+	/*
+	 * void pmull_ghash_update(int blocks, u64 dg[], const char *src,
+	 *			   struct ghash_key const *k, const char *head)
+	 */
+ENTRY(pmull_ghash_update)
+	vld1.8		{SHASH}, [r3]
+	vld1.8		{XL}, [r1]
+	vmov.i8		MASK, #0xe1
+	vext.8		SHASH2, SHASH, SHASH, #8
+	vshl.u64	MASK, MASK, #57
+	veor		SHASH2, SHASH2, SHASH
+
+	/* do the head block first, if supplied */
+	ldr		ip, [sp]
+	teq		ip, #0
+	beq		0f
+	vld1.8		{T1}, [ip]
+	teq		r0, #0
+	b		1f
+
+0:	vld1.8		{T1}, [r2]!
+	subs		r0, r0, #1
+
+1:	/* multiply XL by SHASH in GF(2^128) */
+	vrev64.8	T1, T1
+
+	vext.8		T2, XL, XL, #8
+	vext.8		IN1, T1, T1, #8
+	veor		T1, T1, T2
+	veor		XL, XL, IN1
+
+	vmull.p64	XH, SHASH_H, XL_H		@ a1 * b1
+	veor		T1, T1, XL
+	vmull.p64	XL, SHASH_L, XL_L		@ a0 * b0
+	vmull.p64	XM, SHASH2_L, T1_L		@ (a1 + a0)(b1 + b0)
+
+	vext.8		T1, XL, XH, #8
+	veor		T2, XL, XH
+	veor		XM, XM, T1
+	veor		XM, XM, T2
+	vmull.p64	T2, XL_L, MASK_L
+
+	vmov		XH_L, XM_H
+	vmov		XM_H, XL_L
+
+	veor		XL, XM, T2
+	vext.8		T2, XL, XL, #8
+	vmull.p64	XL, XL_L, MASK_L
+	veor		T2, T2, XH
+	veor		XL, XL, T2
+
+	bne		0b
+
+	vst1.8		{XL}, [r1]
+	bx		lr
+ENDPROC(pmull_ghash_update)
diff --git a/arch/arm/crypto/ghash-ce-glue.c b/arch/arm/crypto/ghash-ce-glue.c
new file mode 100644
index 000000000000..8c959d128065
--- /dev/null
+++ b/arch/arm/crypto/ghash-ce-glue.c
@@ -0,0 +1,318 @@ 
+/*
+ * Accelerated GHASH implementation with ARMv8 vmull.p64 instructions.
+ *
+ * Copyright (C) 2015 Linaro Ltd. <ard.biesheuvel@linaro.org>
+ *
+ * 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 <asm/hwcap.h>
+#include <asm/neon.h>
+#include <asm/simd.h>
+#include <asm/unaligned.h>
+#include <crypto/cryptd.h>
+#include <crypto/internal/hash.h>
+#include <crypto/gf128mul.h>
+#include <linux/crypto.h>
+#include <linux/module.h>
+
+MODULE_DESCRIPTION("GHASH secure hash using ARMv8 Crypto Extensions");
+MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
+MODULE_LICENSE("GPL v2");
+
+#define GHASH_BLOCK_SIZE	16
+#define GHASH_DIGEST_SIZE	16
+
+struct ghash_key {
+	u64	a;
+	u64	b;
+};
+
+struct ghash_desc_ctx {
+	u64 digest[GHASH_DIGEST_SIZE/sizeof(u64)];
+	u8 buf[GHASH_BLOCK_SIZE];
+	u32 count;
+};
+
+struct ghash_async_ctx {
+	struct cryptd_ahash *cryptd_tfm;
+};
+
+asmlinkage void pmull_ghash_update(int blocks, u64 dg[], const char *src,
+				   struct ghash_key const *k, const char *head);
+
+static int ghash_init(struct shash_desc *desc)
+{
+	struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
+
+	*ctx = (struct ghash_desc_ctx){};
+	return 0;
+}
+
+static int ghash_update(struct shash_desc *desc, const u8 *src,
+			unsigned int len)
+{
+	struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
+	unsigned int partial = ctx->count % GHASH_BLOCK_SIZE;
+
+	ctx->count += len;
+
+	if ((partial + len) >= GHASH_BLOCK_SIZE) {
+		struct ghash_key *key = crypto_shash_ctx(desc->tfm);
+		int blocks;
+
+		if (partial) {
+			int p = GHASH_BLOCK_SIZE - partial;
+
+			memcpy(ctx->buf + partial, src, p);
+			src += p;
+			len -= p;
+		}
+
+		blocks = len / GHASH_BLOCK_SIZE;
+		len %= GHASH_BLOCK_SIZE;
+
+		kernel_neon_begin();
+		pmull_ghash_update(blocks, ctx->digest, src, key,
+				   partial ? ctx->buf : NULL);
+		kernel_neon_end();
+		src += blocks * GHASH_BLOCK_SIZE;
+		partial = 0;
+	}
+	if (len)
+		memcpy(ctx->buf + partial, src, len);
+	return 0;
+}
+
+static int ghash_final(struct shash_desc *desc, u8 *dst)
+{
+	struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
+	unsigned int partial = ctx->count % GHASH_BLOCK_SIZE;
+
+	if (partial) {
+		struct ghash_key *key = crypto_shash_ctx(desc->tfm);
+
+		memset(ctx->buf + partial, 0, GHASH_BLOCK_SIZE - partial);
+		kernel_neon_begin();
+		pmull_ghash_update(1, ctx->digest, ctx->buf, key, NULL);
+		kernel_neon_end();
+	}
+	put_unaligned_be64(ctx->digest[1], dst);
+	put_unaligned_be64(ctx->digest[0], dst + 8);
+
+	*ctx = (struct ghash_desc_ctx){};
+	return 0;
+}
+
+static int ghash_setkey(struct crypto_shash *tfm,
+			const u8 *inkey, unsigned int keylen)
+{
+	struct ghash_key *key = crypto_shash_ctx(tfm);
+	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) */
+	b = get_unaligned_be64(inkey);
+	a = get_unaligned_be64(inkey + 8);
+
+	key->a = (a << 1) | (b >> 63);
+	key->b = (b << 1) | (a >> 63);
+
+	if (b >> 63)
+		key->b ^= 0xc200000000000000UL;
+
+	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 = "__driver-ghash-ce",
+		.cra_priority	= 0,
+		.cra_flags	= CRYPTO_ALG_TYPE_SHASH,
+		.cra_blocksize	= GHASH_BLOCK_SIZE,
+		.cra_ctxsize	= sizeof(struct ghash_key),
+		.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;
+
+	if (!may_use_simd()) {
+		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 (!may_use_simd()) {
+		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 (!may_use_simd()) {
+		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 (!may_use_simd()) {
+		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("__driver-ghash-ce", 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,
+	.halg.base		= {
+		.cra_name	= "ghash",
+		.cra_driver_name = "ghash-ce",
+		.cra_priority	= 300,
+		.cra_flags	= CRYPTO_ALG_TYPE_AHASH | CRYPTO_ALG_ASYNC,
+		.cra_blocksize	= GHASH_BLOCK_SIZE,
+		.cra_type	= &crypto_ahash_type,
+		.cra_ctxsize	= sizeof(struct ghash_async_ctx),
+		.cra_module	= THIS_MODULE,
+		.cra_init	= ghash_async_init_tfm,
+		.cra_exit	= ghash_async_exit_tfm,
+	},
+};
+
+static int __init ghash_ce_mod_init(void)
+{
+	int err;
+
+	if (!(elf_hwcap2 & HWCAP2_PMULL))
+		return -ENODEV;
+
+	err = crypto_register_shash(&ghash_alg);
+	if (err)
+		return err;
+	err = crypto_register_ahash(&ghash_async_alg);
+	if (err)
+		goto err_shash;
+
+	return 0;
+
+err_shash:
+	crypto_unregister_shash(&ghash_alg);
+	return err;
+}
+
+static void __exit ghash_ce_mod_exit(void)
+{
+	crypto_unregister_ahash(&ghash_async_alg);
+	crypto_unregister_shash(&ghash_alg);
+}
+
+module_init(ghash_ce_mod_init);
+module_exit(ghash_ce_mod_exit);