crypto: arm/aes - replace bit-sliced OpenSSL NEON code

This replaces the unwieldy generated implementation of bit-sliced AES
in CBC/CTR/XTS modes that originated in the OpenSSL project with a
new version that is heavily based on the OpenSSL implementation, but
has a number of advantages over the old version:
- it does not rely on the scalar AES cipher that also originated in the
  OpenSSL project and contains redundant lookup tables and key schedule
  generation routines (which we already have in crypto/aes_generic.)
- it uses the same expanded key schedule for encryption and decryption,
  reducing the size of the per-key data structure by 1696 bytes
- it adds an implementation of AES in ECB mode, which can be wrapped by
  other generic chaining mode implementations
- it moves the handling of corner cases that are non critical to performance
  to the glue layer written in C
- it was written directly in assembler rather than generated from a Perl
  script

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 405 insertions, 0 deletions

diff --git a/arch/arm/crypto/aes-neonbs-glue.c b/arch/arm/crypto/aes-neonbs-glue.c
new file mode 100644
index 000000000000..e262f99a44d3
--- /dev/null
+++ b/arch/arm/crypto/aes-neonbs-glue.c
@@ -0,0 +1,405 @@
+/*
+ * Bit sliced AES using NEON instructions
+ *
+ * Copyright (C) 2017 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/neon.h>
+#include <crypto/aes.h>
+#include <crypto/cbc.h>
+#include <crypto/internal/simd.h>
+#include <crypto/internal/skcipher.h>
+#include <crypto/xts.h>
+#include <linux/module.h>
+
+MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
+MODULE_LICENSE("GPL v2");
+
+MODULE_ALIAS_CRYPTO("ecb(aes)");
+MODULE_ALIAS_CRYPTO("cbc(aes)");
+MODULE_ALIAS_CRYPTO("ctr(aes)");
+MODULE_ALIAS_CRYPTO("xts(aes)");
+
+asmlinkage void aesbs_convert_key(u8 out[], u32 const rk[], int rounds);
+
+asmlinkage void aesbs_ecb_encrypt(u8 out[], u8 const in[], u8 const rk[],
+				  int rounds, int blocks);
+asmlinkage void aesbs_ecb_decrypt(u8 out[], u8 const in[], u8 const rk[],
+				  int rounds, int blocks);
+
+asmlinkage void aesbs_cbc_decrypt(u8 out[], u8 const in[], u8 const rk[],
+				  int rounds, int blocks, u8 iv[]);
+
+asmlinkage void aesbs_ctr_encrypt(u8 out[], u8 const in[], u8 const rk[],
+				  int rounds, int blocks, u8 ctr[], bool final);
+
+asmlinkage void aesbs_xts_encrypt(u8 out[], u8 const in[], u8 const rk[],
+				  int rounds, int blocks, u8 iv[]);
+asmlinkage void aesbs_xts_decrypt(u8 out[], u8 const in[], u8 const rk[],
+				  int rounds, int blocks, u8 iv[]);
+
+asmlinkage void __aes_arm_encrypt(const u32 rk[], int rounds, const u8 in[],
+				  u8 out[]);
+
+struct aesbs_ctx {
+	int	rounds;
+	u8	rk[13 * (8 * AES_BLOCK_SIZE) + 32] __aligned(AES_BLOCK_SIZE);
+};
+
+struct aesbs_cbc_ctx {
+	struct aesbs_ctx	key;
+	u32			enc[AES_MAX_KEYLENGTH_U32];
+};
+
+struct aesbs_xts_ctx {
+	struct aesbs_ctx	key;
+	u32			twkey[AES_MAX_KEYLENGTH_U32];
+};
+
+static int aesbs_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
+			unsigned int key_len)
+{
+	struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct crypto_aes_ctx rk;
+	int err;
+
+	err = crypto_aes_expand_key(&rk, in_key, key_len);
+	if (err)
+		return err;
+
+	ctx->rounds = 6 + key_len / 4;
+
+	kernel_neon_begin();
+	aesbs_convert_key(ctx->rk, rk.key_enc, ctx->rounds);
+	kernel_neon_end();
+
+	return 0;
+}
+
+static int __ecb_crypt(struct skcipher_request *req,
+		       void (*fn)(u8 out[], u8 const in[], u8 const rk[],
+				  int rounds, int blocks))
+{
+	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+	struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct skcipher_walk walk;
+	int err;
+
+	err = skcipher_walk_virt(&walk, req, true);
+
+	kernel_neon_begin();
+	while (walk.nbytes >= AES_BLOCK_SIZE) {
+		unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
+
+		if (walk.nbytes < walk.total)
+			blocks = round_down(blocks,
+					    walk.stride / AES_BLOCK_SIZE);
+
+		fn(walk.dst.virt.addr, walk.src.virt.addr, ctx->rk,
+		   ctx->rounds, blocks);
+		err = skcipher_walk_done(&walk,
+					 walk.nbytes - blocks * AES_BLOCK_SIZE);
+	}
+	kernel_neon_end();
+
+	return err;
+}
+
+static int ecb_encrypt(struct skcipher_request *req)
+{
+	return __ecb_crypt(req, aesbs_ecb_encrypt);
+}
+
+static int ecb_decrypt(struct skcipher_request *req)
+{
+	return __ecb_crypt(req, aesbs_ecb_decrypt);
+}
+
+static int aesbs_cbc_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
+			    unsigned int key_len)
+{
+	struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct crypto_aes_ctx rk;
+	int err;
+
+	err = crypto_aes_expand_key(&rk, in_key, key_len);
+	if (err)
+		return err;
+
+	ctx->key.rounds = 6 + key_len / 4;
+
+	memcpy(ctx->enc, rk.key_enc, sizeof(ctx->enc));
+
+	kernel_neon_begin();
+	aesbs_convert_key(ctx->key.rk, rk.key_enc, ctx->key.rounds);
+	kernel_neon_end();
+
+	return 0;
+}
+
+static void cbc_encrypt_one(struct crypto_skcipher *tfm, const u8 *src, u8 *dst)
+{
+	struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
+
+	__aes_arm_encrypt(ctx->enc, ctx->key.rounds, src, dst);
+}
+
+static int cbc_encrypt(struct skcipher_request *req)
+{
+	return crypto_cbc_encrypt_walk(req, cbc_encrypt_one);
+}
+
+static int cbc_decrypt(struct skcipher_request *req)
+{
+	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+	struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct skcipher_walk walk;
+	int err;
+
+	err = skcipher_walk_virt(&walk, req, true);
+
+	kernel_neon_begin();
+	while (walk.nbytes >= AES_BLOCK_SIZE) {
+		unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
+
+		if (walk.nbytes < walk.total)
+			blocks = round_down(blocks,
+					    walk.stride / AES_BLOCK_SIZE);
+
+		aesbs_cbc_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
+				  ctx->key.rk, ctx->key.rounds, blocks,
+				  walk.iv);
+		err = skcipher_walk_done(&walk,
+					 walk.nbytes - blocks * AES_BLOCK_SIZE);
+	}
+	kernel_neon_end();
+
+	return err;
+}
+
+static int ctr_encrypt(struct skcipher_request *req)
+{
+	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+	struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct skcipher_walk walk;
+	int err;
+
+	err = skcipher_walk_virt(&walk, req, true);
+
+	kernel_neon_begin();
+	while (walk.nbytes > 0) {
+		unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
+		bool final = (walk.total % AES_BLOCK_SIZE) != 0;
+
+		if (walk.nbytes < walk.total) {
+			blocks = round_down(blocks,
+					    walk.stride / AES_BLOCK_SIZE);
+			final = false;
+		}
+
+		aesbs_ctr_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
+				  ctx->rk, ctx->rounds, blocks, walk.iv, final);
+
+		if (final) {
+			u8 *dst = walk.dst.virt.addr + blocks * AES_BLOCK_SIZE;
+			u8 *src = walk.src.virt.addr + blocks * AES_BLOCK_SIZE;
+
+			if (dst != src)
+				memcpy(dst, src, walk.total % AES_BLOCK_SIZE);
+			crypto_xor(dst, walk.iv, walk.total % AES_BLOCK_SIZE);
+
+			err = skcipher_walk_done(&walk, 0);
+			break;
+		}
+		err = skcipher_walk_done(&walk,
+					 walk.nbytes - blocks * AES_BLOCK_SIZE);
+	}
+	kernel_neon_end();
+
+	return err;
+}
+
+static int aesbs_xts_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
+			    unsigned int key_len)
+{
+	struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct crypto_aes_ctx rk;
+	int err;
+
+	err = xts_verify_key(tfm, in_key, key_len);
+	if (err)
+		return err;
+
+	key_len /= 2;
+	err = crypto_aes_expand_key(&rk, in_key + key_len, key_len);
+	if (err)
+		return err;
+
+	memcpy(ctx->twkey, rk.key_enc, sizeof(ctx->twkey));
+
+	return aesbs_setkey(tfm, in_key, key_len);
+}
+
+static int __xts_crypt(struct skcipher_request *req,
+		       void (*fn)(u8 out[], u8 const in[], u8 const rk[],
+				  int rounds, int blocks, u8 iv[]))
+{
+	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+	struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
+	struct skcipher_walk walk;
+	int err;
+
+	err = skcipher_walk_virt(&walk, req, true);
+
+	__aes_arm_encrypt(ctx->twkey, ctx->key.rounds, walk.iv, walk.iv);
+
+	kernel_neon_begin();
+	while (walk.nbytes >= AES_BLOCK_SIZE) {
+		unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
+
+		if (walk.nbytes < walk.total)
+			blocks = round_down(blocks,
+					    walk.stride / AES_BLOCK_SIZE);
+
+		fn(walk.dst.virt.addr, walk.src.virt.addr, ctx->key.rk,
+		   ctx->key.rounds, blocks, walk.iv);
+		err = skcipher_walk_done(&walk,
+					 walk.nbytes - blocks * AES_BLOCK_SIZE);
+	}
+	kernel_neon_end();
+
+	return err;
+}
+
+static int xts_encrypt(struct skcipher_request *req)
+{
+	return __xts_crypt(req, aesbs_xts_encrypt);
+}
+
+static int xts_decrypt(struct skcipher_request *req)
+{
+	return __xts_crypt(req, aesbs_xts_decrypt);
+}
+
+static struct skcipher_alg aes_algs[] = { {
+	.base.cra_name		= "__ecb(aes)",
+	.base.cra_driver_name	= "__ecb-aes-neonbs",
+	.base.cra_priority	= 250,
+	.base.cra_blocksize	= AES_BLOCK_SIZE,
+	.base.cra_ctxsize	= sizeof(struct aesbs_ctx),
+	.base.cra_module	= THIS_MODULE,
+	.base.cra_flags		= CRYPTO_ALG_INTERNAL,
+
+	.min_keysize		= AES_MIN_KEY_SIZE,
+	.max_keysize		= AES_MAX_KEY_SIZE,
+	.walksize		= 8 * AES_BLOCK_SIZE,
+	.setkey			= aesbs_setkey,
+	.encrypt		= ecb_encrypt,
+	.decrypt		= ecb_decrypt,
+}, {
+	.base.cra_name		= "__cbc(aes)",
+	.base.cra_driver_name	= "__cbc-aes-neonbs",
+	.base.cra_priority	= 250,
+	.base.cra_blocksize	= AES_BLOCK_SIZE,
+	.base.cra_ctxsize	= sizeof(struct aesbs_cbc_ctx),
+	.base.cra_module	= THIS_MODULE,
+	.base.cra_flags		= CRYPTO_ALG_INTERNAL,
+
+	.min_keysize		= AES_MIN_KEY_SIZE,
+	.max_keysize		= AES_MAX_KEY_SIZE,
+	.walksize		= 8 * AES_BLOCK_SIZE,
+	.ivsize			= AES_BLOCK_SIZE,
+	.setkey			= aesbs_cbc_setkey,
+	.encrypt		= cbc_encrypt,
+	.decrypt		= cbc_decrypt,
+}, {
+	.base.cra_name		= "__ctr(aes)",
+	.base.cra_driver_name	= "__ctr-aes-neonbs",
+	.base.cra_priority	= 250,
+	.base.cra_blocksize	= 1,
+	.base.cra_ctxsize	= sizeof(struct aesbs_ctx),
+	.base.cra_module	= THIS_MODULE,
+	.base.cra_flags		= CRYPTO_ALG_INTERNAL,
+
+	.min_keysize		= AES_MIN_KEY_SIZE,
+	.max_keysize		= AES_MAX_KEY_SIZE,
+	.chunksize		= AES_BLOCK_SIZE,
+	.walksize		= 8 * AES_BLOCK_SIZE,
+	.ivsize			= AES_BLOCK_SIZE,
+	.setkey			= aesbs_setkey,
+	.encrypt		= ctr_encrypt,
+	.decrypt		= ctr_encrypt,
+}, {
+	.base.cra_name		= "__xts(aes)",
+	.base.cra_driver_name	= "__xts-aes-neonbs",
+	.base.cra_priority	= 250,
+	.base.cra_blocksize	= AES_BLOCK_SIZE,
+	.base.cra_ctxsize	= sizeof(struct aesbs_xts_ctx),
+	.base.cra_module	= THIS_MODULE,
+	.base.cra_flags		= CRYPTO_ALG_INTERNAL,
+
+	.min_keysize		= 2 * AES_MIN_KEY_SIZE,
+	.max_keysize		= 2 * AES_MAX_KEY_SIZE,
+	.walksize		= 8 * AES_BLOCK_SIZE,
+	.ivsize			= AES_BLOCK_SIZE,
+	.setkey			= aesbs_xts_setkey,
+	.encrypt		= xts_encrypt,
+	.decrypt		= xts_decrypt,
+} };
+
+static struct simd_skcipher_alg *aes_simd_algs[ARRAY_SIZE(aes_algs)];
+
+static void aes_exit(void)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(aes_simd_algs); i++)
+		if (aes_simd_algs[i])
+			simd_skcipher_free(aes_simd_algs[i]);
+
+	crypto_unregister_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
+}
+
+static int __init aes_init(void)
+{
+	struct simd_skcipher_alg *simd;
+	const char *basename;
+	const char *algname;
+	const char *drvname;
+	int err;
+	int i;
+
+	if (!(elf_hwcap & HWCAP_NEON))
+		return -ENODEV;
+
+	err = crypto_register_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
+	if (err)
+		return err;
+
+	for (i = 0; i < ARRAY_SIZE(aes_algs); i++) {
+		if (!(aes_algs[i].base.cra_flags & CRYPTO_ALG_INTERNAL))
+			continue;
+
+		algname = aes_algs[i].base.cra_name + 2;
+		drvname = aes_algs[i].base.cra_driver_name + 2;
+		basename = aes_algs[i].base.cra_driver_name;
+		simd = simd_skcipher_create_compat(algname, drvname, basename);
+		err = PTR_ERR(simd);
+		if (IS_ERR(simd))
+			goto unregister_simds;
+
+		aes_simd_algs[i] = simd;
+	}
+	return 0;
+
+unregister_simds:
+	aes_exit();
+	return err;
+}
+
+module_init(aes_init);
+module_exit(aes_exit);