diff mbox

[RFC] arm64: add support for AES in CCM mode using Crypto Extensions

Message ID 1392106905-28709-1-git-send-email-ard.biesheuvel@linaro.org (mailing list archive)
State New, archived
Headers show

Commit Message

Ard Biesheuvel Feb. 11, 2014, 8:21 a.m. UTC 
This adds support for a synchronous implementation of AES in CCM mode
using ARMv8 Crypto Extensions, using NEON registers q0 - q5.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
Hi all,

I am posting this for review/RFC. The main topic for feedback is the way
I have used an inner blkcipher instance to process the encrypted + authenticated
data.

The point of having a dedicated module for synchronous ccm(aes) is the fact that
mac80211 uses it for WPA2 CCMP en-/decryption, where it runs entirely in soft
IRQ context. In this case, the performance improvement offered by dedicated AES
instructions is likely wasted on stacking and unstacking the NEON register file,
as the generic CCM operates on a single AES block at a time.

Instead, this implementation interleaves the CTR and CBC modes at the round
level, eliminating 50% of both the input and round key loads and (hopefully)
eliminating pipeline stalls by operating on two AES blocks at a time.

Tested with tcrypt, no performance numbers yet.

Comments

Herbert Xu Feb. 25, 2014, 7:02 a.m. UTC | #1 
On Tue, Feb 11, 2014 at 09:21:45AM +0100, Ard Biesheuvel wrote:
> This adds support for a synchronous implementation of AES in CCM mode
> using ARMv8 Crypto Extensions, using NEON registers q0 - q5.
> 
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
> Hi all,
> 
> I am posting this for review/RFC. The main topic for feedback is the way
> I have used an inner blkcipher instance to process the encrypted + authenticated
> data.
> 
> The point of having a dedicated module for synchronous ccm(aes) is the fact that
> mac80211 uses it for WPA2 CCMP en-/decryption, where it runs entirely in soft
> IRQ context. In this case, the performance improvement offered by dedicated AES
> instructions is likely wasted on stacking and unstacking the NEON register file,
> as the generic CCM operates on a single AES block at a time.
> 
> Instead, this implementation interleaves the CTR and CBC modes at the round
> level, eliminating 50% of both the input and round key loads and (hopefully)
> eliminating pipeline stalls by operating on two AES blocks at a time.
> 
> Tested with tcrypt, no performance numbers yet.

I think your idea definitely make sense, since we do the same
thing in aesni-intel.

It'll be interesting to see some numbers, especially if we could
compare this against the generic version that we talked about
earlier.

Thanks,
Ard Biesheuvel Feb. 25, 2014, 7:12 a.m. UTC | #2 
On 25 February 2014 08:02, Herbert Xu <herbert@gondor.apana.org.au> wrote:
> On Tue, Feb 11, 2014 at 09:21:45AM +0100, Ard Biesheuvel wrote:
>> This adds support for a synchronous implementation of AES in CCM mode
>> using ARMv8 Crypto Extensions, using NEON registers q0 - q5.
>>
>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>> ---
>> Hi all,
>>
>> I am posting this for review/RFC. The main topic for feedback is the way
>> I have used an inner blkcipher instance to process the encrypted + authenticated
>> data.
>>
>> The point of having a dedicated module for synchronous ccm(aes) is the fact that
>> mac80211 uses it for WPA2 CCMP en-/decryption, where it runs entirely in soft
>> IRQ context. In this case, the performance improvement offered by dedicated AES
>> instructions is likely wasted on stacking and unstacking the NEON register file,
>> as the generic CCM operates on a single AES block at a time.
>>
>> Instead, this implementation interleaves the CTR and CBC modes at the round
>> level, eliminating 50% of both the input and round key loads and (hopefully)
>> eliminating pipeline stalls by operating on two AES blocks at a time.
>>
>> Tested with tcrypt, no performance numbers yet.
>
> I think your idea definitely make sense, since we do the same
> thing in aesni-intel.
>
> It'll be interesting to see some numbers, especially if we could
> compare this against the generic version that we talked about
> earlier.
>

Hi Herbert,

Thanks for taking a look.

I will definitely come back with performance numbers as soon as I
manage to produce any.
Do you have any comments specifically about using an inner blkcipher
instance to implement the aead?

Thanks,
Ard.
Herbert Xu Feb. 25, 2014, 7:16 a.m. UTC | #3 
On Tue, Feb 25, 2014 at 08:12:36AM +0100, Ard Biesheuvel wrote:
>
> Do you have any comments specifically about using an inner blkcipher
> instance to implement the aead?

Indeed, the inner block cipher looks superfluous since it's only
used once by ccm and there is no nesting similar to aesni-intel.

Inner algorithms are only needed if you want to nest it, e.g.,
through fpu().  Otherwise I don't see any difference vs. calling
the underlying functions directly, especially since you seem to
be calling them directly anyway.

Cheers,
Ard Biesheuvel Feb. 25, 2014, 7:21 a.m. UTC | #4 
On 25 February 2014 08:16, Herbert Xu <herbert@gondor.apana.org.au> wrote:
> On Tue, Feb 25, 2014 at 08:12:36AM +0100, Ard Biesheuvel wrote:
>>
>> Do you have any comments specifically about using an inner blkcipher
>> instance to implement the aead?
>
> Indeed, the inner block cipher looks superfluous since it's only
> used once by ccm and there is no nesting similar to aesni-intel.
>
> Inner algorithms are only needed if you want to nest it, e.g.,
> through fpu().  Otherwise I don't see any difference vs. calling
> the underlying functions directly, especially since you seem to
> be calling them directly anyway.
>

Well, the problem is that aead does not provide the blkcipher walk
API, which means it is up to the caller to map/unmap the scatterlists
and keep track of the in and out pointers etc.

For the authenticate-only data, this is manageable as you are only
dealing with input, but when dealing with both in- and output, as in
the core of CCM, it becomes very tedious.
So instead, I have opted for an inner blkcipher instance which takes
care of all of that. Could you suggest another approach that if
preferable?

Thanks,
Ard.
Herbert Xu Feb. 25, 2014, 9:08 a.m. UTC | #5 
On Tue, Feb 25, 2014 at 08:21:22AM +0100, Ard Biesheuvel wrote:
> 
> For the authenticate-only data, this is manageable as you are only
> dealing with input, but when dealing with both in- and output, as in
> the core of CCM, it becomes very tedious.
> So instead, I have opted for an inner blkcipher instance which takes
> care of all of that. Could you suggest another approach that if
> preferable?

I don't think the walk helper actually needs the tfm apart from
getting a couple of parameters out of it, so perhaps we can just
change the helper to not depend on a tfm.

Cheers,
Ard Biesheuvel Feb. 25, 2014, 10:11 a.m. UTC | #6 
On 25 February 2014 10:08, Herbert Xu <herbert@gondor.apana.org.au> wrote:
> On Tue, Feb 25, 2014 at 08:21:22AM +0100, Ard Biesheuvel wrote:
>>
>> For the authenticate-only data, this is manageable as you are only
>> dealing with input, but when dealing with both in- and output, as in
>> the core of CCM, it becomes very tedious.
>> So instead, I have opted for an inner blkcipher instance which takes
>> care of all of that. Could you suggest another approach that if
>> preferable?
>
> I don't think the walk helper actually needs the tfm apart from
> getting a couple of parameters out of it, so perhaps we can just
> change the helper to not depend on a tfm.
>

That seems like a less hacky approach.

I'll cook something up and put it on the list.

Cheers,
Ard.
diff mbox

Patch

diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index e0b75464b7f1..a4b3e253557d 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -46,6 +46,7 @@  core-y		+= arch/arm64/emu/
 core-y		+= arch/arm64/kernel/ arch/arm64/mm/
 core-$(CONFIG_KVM) += arch/arm64/kvm/
 core-$(CONFIG_XEN) += arch/arm64/xen/
+core-$(CONFIG_CRYPTO) += arch/arm64/crypto/
 libs-y		:= arch/arm64/lib/ $(libs-y)
 libs-y		+= $(LIBGCC)
 
diff --git a/arch/arm64/crypto/Makefile b/arch/arm64/crypto/Makefile
new file mode 100644
index 000000000000..ba10ebb53e9e
--- /dev/null
+++ b/arch/arm64/crypto/Makefile
@@ -0,0 +1,12 @@ 
+#
+# linux/arch/arm64/crypto/Makefile
+#
+# Copyright (C) 2013 - 2014 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.
+#
+
+aesce-ccm-y	:= aesce-ccm-glue.o aesce-ccm-core.o
+obj-m		+= aesce-ccm.o
diff --git a/arch/arm64/crypto/aesce-ccm-core.S b/arch/arm64/crypto/aesce-ccm-core.S
new file mode 100644
index 000000000000..f808c17eac45
--- /dev/null
+++ b/arch/arm64/crypto/aesce-ccm-core.S
@@ -0,0 +1,222 @@ 
+/*
+ * linux/arch/arm64/crypto/aesce-ccm-core.S - AES-CCM transform for
+ *                                            ARMv8 with Crypto Extensions
+ *
+ * Copyright (C) 2013 - 2014 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>
+
+	.text
+	.arch	armv8-a+crypto
+
+	/*
+	 * void ce_aes_ccm_auth_data(u8 mac[], u8 const in[], u32 abytes,
+	 *			     u32 *macp, u8 const rk[], u32 rounds);
+	 */
+ENTRY(ce_aes_ccm_auth_data)
+	ldr	w8, [x3]			/* leftover from prev round? */
+	ld1	{v0.2d}, [x0]			/* load mac */
+	cbz	w8, 1f
+	sub	w8, w8, #16
+	eor	v1.16b, v1.16b, v1.16b
+0:	ldrb	w7, [x1], #1			/* get 1 byte of input */
+	subs	w2, w2, #1
+	add	w8, w8, #1
+	ins	v1.b[0], w7
+	ext	v1.16b, v1.16b, v1.16b, #1	/* rotate in the input bytes */
+	beq	8f				/* out of input? */
+	cbnz	w8, 0b
+	eor	v0.16b, v0.16b, v1.16b
+1:	ld1	{v3.2d}, [x4]			/* load first round key */
+	prfm	pldl1strm, [x1]
+	cmp	w5, #12				/* which key size? */
+	add	x6, x4, #16
+	sub	w7, w5, #2			/* modified # of rounds */
+	bmi	2f
+	bne	5f
+	mov	v5.16b, v3.16b
+	b	4f
+2:	mov	v4.16b, v3.16b
+	ld1	{v5.2d}, [x6], #16		/* load 2nd round key */
+3:	aese	v0.16b, v4.16b
+	aesmc	v0.16b, v0.16b
+4:	ld1	{v3.2d}, [x6], #16		/* load next round key */
+	aese	v0.16b, v5.16b
+	aesmc	v0.16b, v0.16b
+5:	ld1	{v4.2d}, [x6], #16		/* load next round key */
+	subs	w7, w7, #3
+	aese	v0.16b, v3.16b
+	aesmc	v0.16b, v0.16b
+	ld1	{v5.2d}, [x6], #16		/* load next round key */
+	bpl	3b
+	aese	v0.16b, v4.16b
+	subs	w2, w2, #16			/* last data? */
+	eor	v0.16b, v0.16b, v5.16b		/* final round */
+	bmi	6f
+	ld1	{v1.16b}, [x1], #16		/* load next input block */
+	eor	v0.16b, v0.16b, v1.16b		/* xor with mac */
+	bne	1b
+6:	st1	{v0.2d}, [x0]			/* store mac */
+	beq	10f
+	adds	w2, w2, #16
+	beq	10f
+	mov	w8, w2
+7:	ldrb	w7, [x1], #1
+	umov	w6, v0.b[0]
+	eor	w6, w6, w7
+	strb	w6, [x0], #1
+	subs	w2, w2, #1
+	beq	10f
+	ext	v0.16b, v0.16b, v0.16b, #1	/* rotate out the mac bytes */
+	b	7b
+8:	mov	w7, w8
+	add	w8, w8, #16
+9:	ext	v1.16b, v1.16b, v1.16b, #1
+	adds	w7, w7, #1
+	bne	9b
+	eor	v0.16b, v0.16b, v1.16b
+	st1	{v0.2d}, [x0]
+10:	str	w8, [x3]
+	ret
+ENDPROC(ce_aes_ccm_auth_data)
+
+	/*
+	 * void ce_aes_ccm_final(u8 mac[], u8 const ctr[], u8 const rk[],
+	 * 			 u32 rounds);
+	 */
+ENTRY(ce_aes_ccm_final)
+	ld1	{v3.2d}, [x2], #16		/* load first round key */
+	ld1	{v0.2d}, [x0]			/* load mac */
+	cmp	w3, #12				/* which key size? */
+	sub	w3, w3, #2			/* modified # of rounds */
+	ld1	{v1.2d}, [x1]			/* load 1st ctriv */
+	bmi	0f
+	bne	3f
+	mov	v5.16b, v3.16b
+	b	2f
+0:	mov	v4.16b, v3.16b
+1:	ld1	{v5.2d}, [x2], #16		/* load next round key */
+	aese	v0.16b, v4.16b
+	aesmc	v0.16b, v0.16b
+	aese	v1.16b, v4.16b
+	aesmc	v1.16b, v1.16b
+2:	ld1	{v3.2d}, [x2], #16		/* load next round key */
+	aese	v0.16b, v5.16b
+	aesmc	v0.16b, v0.16b
+	aese	v1.16b, v5.16b
+	aesmc	v1.16b, v1.16b
+3:	ld1	{v4.2d}, [x2], #16		/* load next round key */
+	subs	w3, w3, #3
+	aese	v0.16b, v3.16b
+	aesmc	v0.16b, v0.16b
+	aese	v1.16b, v3.16b
+	aesmc	v1.16b, v1.16b
+	bpl	1b
+	aese	v0.16b, v4.16b
+	aese	v1.16b, v4.16b
+	/* final round key cancels out */
+	eor	v0.16b, v0.16b, v1.16b		/* en-/decrypt the mac */
+	st1	{v0.2d}, [x0]			/* store result */
+	ret
+ENDPROC(ce_aes_ccm_final)
+
+	.macro	aes_ccm_do_crypt,enc
+	ldr	x8, [x6, #8]			/* load lower ctr */
+	ld1	{v0.2d}, [x5]			/* load mac */
+	rev	x8, x8				/* keep swabbed ctr in reg */
+0:	/* outer loop */
+	ld1	{v1.1d}, [x6]			/* load upper ctr */
+	prfm	pldl1strm, [x1]
+	add	x8, x8, #1
+	rev	x9, x8
+	cmp	w4, #12				/* which key size? */
+	sub	w7, w4, #2			/* get modified # of rounds */
+	ins	v1.d[1], x9			/* no carry in lower ctr */
+	ld1	{v3.2d}, [x3]			/* load first round key */
+	add	x10, x3, #16
+	bmi	1f
+	bne	4f
+	mov	v5.16b, v3.16b
+	b	3f
+1:	mov	v4.16b, v3.16b
+	ld1	{v5.2d}, [x10], #16		/* load 2nd round key */
+2:	/* inner loop: 3 rounds, 2x interleaved */
+	aese	v0.16b, v4.16b
+	aesmc	v0.16b, v0.16b
+	aese	v1.16b, v4.16b
+	aesmc	v1.16b, v1.16b
+3:	ld1	{v3.2d}, [x10], #16		/* load next round key */
+	aese	v0.16b, v5.16b
+	aesmc	v0.16b, v0.16b
+	aese	v1.16b, v5.16b
+	aesmc	v1.16b, v1.16b
+4:	ld1	{v4.2d}, [x10], #16		/* load next round key */
+	subs	w7, w7, #3
+	aese	v0.16b, v3.16b
+	aesmc	v0.16b, v0.16b
+	aese	v1.16b, v3.16b
+	aesmc	v1.16b, v1.16b
+	ld1	{v5.2d}, [x10], #16		/* load next round key */
+	bpl	2b
+	aese	v0.16b, v4.16b
+	aese	v1.16b, v4.16b
+	subs	w2, w2, #16
+	bmi	5f
+	ld1	{v2.16b}, [x1], #16		/* load next input block */
+	.if	\enc == 1
+	eor	v2.16b, v2.16b, v5.16b		/* final round enc+mac */
+	eor	v1.16b, v1.16b, v2.16b		/* xor with crypted ctr */
+	.else
+	eor	v2.16b, v2.16b, v1.16b		/* xor with crypted ctr */
+	eor	v1.16b, v2.16b, v5.16b		/* final round enc */
+	.endif
+	eor	v0.16b, v0.16b, v2.16b		/* xor mac with pt ^ rk[last] */
+	st1	{v1.16b}, [x0], #16		/* write output block */
+	bne	0b
+5:	eor	v0.16b, v0.16b, v5.16b		/* final round mac */
+	eor	v1.16b, v1.16b, v5.16b		/* final round enc */
+	st1	{v0.2d}, [x5]			/* store mac */
+	beq	7f
+	add	w2, w2, #16			/* process partial tail block */
+6:	ldrb	w9, [x1], #1			/* get 1 byte of input */
+	umov	w6, v1.b[0]			/* get top crypted ctr byte */
+	umov	w7, v0.b[0]			/* get top mac byte */
+	.if	\enc == 1
+	eor	w7, w7, w9
+	eor	w9, w9, w6
+	.else
+	eor	w9, w9, w6
+	eor	w7, w7, w9
+	.endif
+	strb	w9, [x0], #1			/* store out byte */
+	strb	w7, [x5], #1			/* store mac byte */
+	subs	w2, w2, #1
+	beq	8f
+	ext	v0.16b, v0.16b, v0.16b, #1	/* shift out mac byte */
+	ext	v1.16b, v1.16b, v1.16b, #1	/* shift out ctr byte */
+	b	6b
+7:	rev	x8, x8
+	str	x8, [x6, #8]			/* store lsb end of ctr (BE) */
+8:	ret
+	.endm
+
+	/*
+	 * void ce_aes_ccm_encrypt(u8 out[], u8 const in[], u32 cbytes,
+	 * 			   u8 const rk[], u32 rounds, u8 mac[],
+	 * 			   u8 ctr[]);
+	 * void ce_aes_ccm_decrypt(u8 out[], u8 const in[], u32 cbytes,
+	 * 			   u8 const rk[], u32 rounds, u8 mac[],
+	 * 			   u8 ctr[]);
+	 */
+ENTRY(ce_aes_ccm_encrypt)
+	aes_ccm_do_crypt	1
+ENDPROC(ce_aes_ccm_encrypt)
+
+ENTRY(ce_aes_ccm_decrypt)
+	aes_ccm_do_crypt	0
+ENDPROC(ce_aes_ccm_decrypt)
diff --git a/arch/arm64/crypto/aesce-ccm-glue.c b/arch/arm64/crypto/aesce-ccm-glue.c
new file mode 100644
index 000000000000..153a40f43a6e
--- /dev/null
+++ b/arch/arm64/crypto/aesce-ccm-glue.c
@@ -0,0 +1,387 @@ 
+/*
+ * linux/arch/arm64/crypto/aes-ccm-glue.c
+ *
+ * Copyright (C) 2013 - 2014 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 <asm/unaligned.h>
+#include <crypto/aes.h>
+#include <crypto/algapi.h>
+#include <crypto/scatterwalk.h>
+#include <linux/crypto.h>
+#include <linux/module.h>
+
+struct crypto_ccm_aes_ctx {
+	struct crypto_aes_ctx	*key;
+	struct crypto_blkcipher	*blk_tfm;
+};
+
+static int num_rounds(struct crypto_aes_ctx *ctx)
+{
+	/*
+	 * # of rounds specified by AES:
+	 * 128 bit key		10 rounds
+	 * 192 bit key		12 rounds
+	 * 256 bit key		14 rounds
+	 * => n byte key	=> 6 + (n/4) rounds
+	 */
+	return 6 + ctx->key_length / 4;
+}
+
+asmlinkage void ce_aes_ccm_auth_data(u8 mac[], u8 const in[], u32 abytes,
+				     u32 *macp, u32 const rk[], u32 rounds);
+
+asmlinkage void ce_aes_ccm_encrypt(u8 out[], u8 const in[], u32 cbytes,
+				   u32 const rk[], u32 rounds, u8 mac[],
+				   u8 ctr[]);
+
+asmlinkage void ce_aes_ccm_decrypt(u8 out[], u8 const in[], u32 cbytes,
+				   u32 const rk[], u32 rounds, u8 mac[],
+				   u8 ctr[]);
+
+asmlinkage void ce_aes_ccm_final(u8 mac[], u8 const ctr[], u32 const rk[],
+				 u32 rounds);
+
+static int ccm_setkey(struct crypto_aead *tfm, const u8 *in_key,
+		      unsigned int key_len)
+{
+	struct crypto_ccm_aes_ctx *ctx = crypto_aead_ctx(tfm);
+	int ret;
+
+	ret = crypto_aes_expand_key(ctx->key, in_key, key_len);
+	if (!ret)
+		return 0;
+
+	tfm->base.crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
+	return -EINVAL;
+}
+
+static int ccm_setauthsize(struct crypto_aead *tfm, unsigned int authsize)
+{
+	if ((authsize & 1) || authsize < 4)
+		return -EINVAL;
+	return 0;
+}
+
+static int ccm_init_mac(struct aead_request *req, u8 maciv[], u32 msglen)
+{
+	struct crypto_aead *aead = crypto_aead_reqtfm(req);
+	__be32 *n = (__be32 *)&maciv[AES_BLOCK_SIZE - 8];
+	u32 l = req->iv[0] + 1;
+
+	/* verify that CCM dimension 'L' is set correctly in the IV */
+	if (l < 2 || l > 8)
+		return -EINVAL;
+
+	/* verify that msglen can in fact be represented in L bytes */
+	if (msglen >> (8 * l))
+		return -EOVERFLOW;
+
+	/*
+	 * Even if the CCM spec allows L values of up to 8, the Linux cryptoapi
+	 * uses a u32 type to represent msglen so the top 4 bytes are always 0.
+	 */
+	n[0] = 0;
+	n[1] = cpu_to_be32(msglen);
+
+	memcpy(maciv, req->iv, AES_BLOCK_SIZE - l);
+
+	/*
+	 * Meaning of byte 0 according to CCM spec (RFC 3610/NIST 800-38C)
+	 * - bits 0..2	: max # of bytes required to represent msglen, minus 1
+	 *                (already set by caller)
+	 * - bits 3..5	: size of auth tag (1 => 4 bytes, 2 => 6 bytes, etc)
+	 * - bit 6	: indicates presence of authenticate-only data
+	 */
+	maciv[0] |= (crypto_aead_authsize(aead) - 2) << 2;
+	if (req->assoclen)
+		maciv[0] |= 0x40;
+
+	memset(&req->iv[AES_BLOCK_SIZE - l], 0, l);
+	return 0;
+}
+
+static void ccm_calculate_auth_mac(struct aead_request *req, u8 mac[])
+{
+	struct crypto_aead *aead = crypto_aead_reqtfm(req);
+	struct crypto_ccm_aes_ctx *ctx = crypto_aead_ctx(aead);
+	struct __packed { __be16 l; __be32 h; u16 len; } ltag;
+	struct scatter_walk walk;
+	u32 len = req->assoclen;
+	u32 macp = 0;
+
+	/* prepend the AAD with a length tag */
+	if (len < 0xff00) {
+		ltag.l = cpu_to_be16(len);
+		ltag.len = 2;
+	} else  {
+		ltag.l = cpu_to_be16(0xfffe);
+		put_unaligned_be32(len, &ltag.h);
+		ltag.len = 6;
+	}
+
+	ce_aes_ccm_auth_data(mac, (u8 *)&ltag, ltag.len, &macp,
+			     ctx->key->key_enc, num_rounds(ctx->key));
+	scatterwalk_start(&walk, req->assoc);
+
+	do {
+		u32 n = scatterwalk_clamp(&walk, len);
+		u8 *p;
+
+		if (!n) {
+			scatterwalk_start(&walk, sg_next(walk.sg));
+			n = scatterwalk_clamp(&walk, len);
+		}
+		p = scatterwalk_map(&walk);
+		ce_aes_ccm_auth_data(mac, p, n, &macp,
+				     ctx->key->key_enc, num_rounds(ctx->key));
+		len -= n;
+
+		scatterwalk_unmap(p);
+		scatterwalk_advance(&walk, n);
+		scatterwalk_done(&walk, 0, len);
+	} while (len);
+}
+
+struct ccm_inner_desc_info {
+	u8	ctriv[AES_BLOCK_SIZE];
+	u8	mac[AES_BLOCK_SIZE];
+} __aligned(8);
+
+static int ccm_inner_encrypt(struct blkcipher_desc *desc,
+			     struct scatterlist *dst, struct scatterlist *src,
+			     unsigned int nbytes)
+{
+	struct crypto_aes_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
+	struct ccm_inner_desc_info *descinfo = desc->info;
+	struct blkcipher_walk walk;
+	int err;
+
+	blkcipher_walk_init(&walk, dst, src, nbytes);
+	err = blkcipher_walk_virt_block(desc, &walk, AES_BLOCK_SIZE);
+
+	while (walk.nbytes) {
+		u32 tail = walk.nbytes % AES_BLOCK_SIZE;
+
+		if (walk.nbytes == nbytes)
+			tail = 0;
+
+		ce_aes_ccm_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
+				   walk.nbytes - tail, ctx->key_enc,
+				   num_rounds(ctx), descinfo->mac,
+				   descinfo->ctriv);
+
+		nbytes -= walk.nbytes - tail;
+		err = blkcipher_walk_done(desc, &walk, tail);
+	}
+	return err;
+}
+
+static int ccm_inner_decrypt(struct blkcipher_desc *desc,
+			     struct scatterlist *dst, struct scatterlist *src,
+			     unsigned int nbytes)
+{
+	struct crypto_aes_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
+	struct ccm_inner_desc_info *descinfo = desc->info;
+	struct blkcipher_walk walk;
+	int err;
+
+	blkcipher_walk_init(&walk, dst, src, nbytes);
+	err = blkcipher_walk_virt_block(desc, &walk, AES_BLOCK_SIZE);
+
+	while (walk.nbytes) {
+		u32 tail = walk.nbytes % AES_BLOCK_SIZE;
+
+		if (walk.nbytes == nbytes)
+			tail = 0;
+
+		ce_aes_ccm_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
+				   walk.nbytes - tail, ctx->key_enc,
+				   num_rounds(ctx), descinfo->mac,
+				   descinfo->ctriv);
+
+		nbytes -= walk.nbytes - tail;
+		err = blkcipher_walk_done(desc, &walk, tail);
+	}
+	return err;
+}
+
+static int ccm_encrypt(struct aead_request *req)
+{
+	struct crypto_aead *aead = crypto_aead_reqtfm(req);
+	struct crypto_ccm_aes_ctx *ctx = crypto_aead_ctx(aead);
+	struct crypto_blkcipher *blk_tfm = ctx->blk_tfm;
+	struct ccm_inner_desc_info descinfo;
+	int err;
+
+	struct blkcipher_desc desc = {
+		.tfm	= blk_tfm,
+		.info	= &descinfo,
+		.flags = 0,
+	};
+
+	err = ccm_init_mac(req, descinfo.mac, req->cryptlen);
+	if (err)
+		return err;
+
+	kernel_neon_begin_partial(6);
+
+	if (req->assoclen)
+		ccm_calculate_auth_mac(req, descinfo.mac);
+
+	memcpy(descinfo.ctriv, req->iv, AES_BLOCK_SIZE);
+
+	/* call inner blkcipher to process the payload */
+	err = crypto_blkcipher_crt(blk_tfm)->encrypt(&desc, req->dst, req->src,
+						     req->cryptlen);
+	if (!err)
+		ce_aes_ccm_final(descinfo.mac, req->iv, ctx->key->key_enc,
+				 num_rounds(ctx->key));
+
+	kernel_neon_end();
+
+	if (err)
+		return err;
+
+	/* copy authtag to end of dst */
+	scatterwalk_map_and_copy(descinfo.mac, req->dst, req->cryptlen,
+				 crypto_aead_authsize(aead), 1);
+
+	return 0;
+}
+
+static int ccm_decrypt(struct aead_request *req)
+{
+	struct crypto_aead *aead = crypto_aead_reqtfm(req);
+	struct crypto_ccm_aes_ctx *ctx = crypto_aead_ctx(aead);
+	struct crypto_blkcipher *blk_tfm = ctx->blk_tfm;
+	struct ccm_inner_desc_info descinfo;
+	u8 atag[AES_BLOCK_SIZE];
+	u32 len;
+	int err;
+
+	struct blkcipher_desc desc = {
+		.tfm	= blk_tfm,
+		.info	= &descinfo,
+		.flags = 0,
+	};
+
+	len = req->cryptlen - crypto_aead_authsize(aead);
+	err = ccm_init_mac(req, descinfo.mac, len);
+	if (err)
+		return err;
+
+	if (req->assoclen)
+		ccm_calculate_auth_mac(req, descinfo.mac);
+
+	memcpy(descinfo.ctriv, req->iv, AES_BLOCK_SIZE);
+
+	kernel_neon_begin_partial(6);
+
+	/* call inner blkcipher to process the payload */
+	err = crypto_blkcipher_crt(blk_tfm)->decrypt(&desc, req->dst, req->src,
+						     len);
+	if (!err)
+		ce_aes_ccm_final(descinfo.mac, req->iv, ctx->key->key_enc,
+				 num_rounds(ctx->key));
+
+	kernel_neon_end();
+
+	if (err)
+		return err;
+
+	/* compare calculated auth tag with the stored one */
+	scatterwalk_map_and_copy(atag, req->src, len,
+				 crypto_aead_authsize(aead), 0);
+
+	if (memcmp(descinfo.mac, atag, crypto_aead_authsize(aead)))
+		return -EBADMSG;
+	return 0;
+}
+
+static int ccm_init(struct crypto_tfm *tfm)
+{
+	struct crypto_ccm_aes_ctx *ctx = crypto_tfm_ctx(tfm);
+	struct crypto_blkcipher *blk_tfm;
+
+	blk_tfm = crypto_alloc_blkcipher("__driver-ccm-aesce-inner", 0, 0);
+	if (IS_ERR(blk_tfm))
+		return PTR_ERR(blk_tfm);
+
+	ctx->blk_tfm = blk_tfm;
+	ctx->key = crypto_blkcipher_ctx(blk_tfm);
+
+	return 0;
+}
+
+static void ccm_exit(struct crypto_tfm *tfm)
+{
+	struct crypto_ccm_aes_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	crypto_free_blkcipher(ctx->blk_tfm);
+}
+
+static struct crypto_alg aes_algs[] = { {
+	.cra_name		= "__ccm-aesce-inner",
+	.cra_driver_name	= "__driver-ccm-aesce-inner",
+	.cra_priority		= 0,
+	.cra_flags		= CRYPTO_ALG_TYPE_BLKCIPHER,
+	.cra_blocksize		= 1,
+	.cra_ctxsize		= sizeof(struct crypto_aes_ctx),
+	.cra_alignmask		= 7,
+	.cra_type		= &crypto_blkcipher_type,
+	.cra_module		= THIS_MODULE,
+	.cra_blkcipher = {
+		.min_keysize	= AES_MIN_KEY_SIZE,
+		.max_keysize	= AES_MAX_KEY_SIZE,
+		.ivsize		= sizeof(struct ccm_inner_desc_info),
+		.setkey		= crypto_aes_set_key,
+		.encrypt	= ccm_inner_encrypt,
+		.decrypt	= ccm_inner_decrypt,
+	},
+}, {
+	.cra_name		= "ccm(aes)",
+	.cra_driver_name	= "ccm-aes-ce",
+	.cra_priority		= 300,
+	.cra_flags		= CRYPTO_ALG_TYPE_AEAD,
+	.cra_blocksize		= 1,
+	.cra_ctxsize		= sizeof(struct crypto_ccm_aes_ctx),
+	.cra_alignmask		= 7,
+	.cra_type		= &crypto_aead_type,
+	.cra_module		= THIS_MODULE,
+	.cra_init		= ccm_init,
+	.cra_exit		= ccm_exit,
+	.cra_aead = {
+		.ivsize		= AES_BLOCK_SIZE,
+		.maxauthsize	= AES_BLOCK_SIZE,
+		.setkey		= ccm_setkey,
+		.setauthsize	= ccm_setauthsize,
+		.encrypt	= ccm_encrypt,
+		.decrypt	= ccm_decrypt,
+	}
+} };
+
+static int __init aes_mod_init(void)
+{
+	if (!(elf_hwcap & HWCAP_AES))
+		return -ENODEV;
+	return crypto_register_algs(aes_algs, ARRAY_SIZE(aes_algs));
+}
+
+static void __exit aes_mod_exit(void)
+{
+	crypto_unregister_algs(aes_algs, ARRAY_SIZE(aes_algs));
+}
+
+module_init(aes_mod_init);
+module_exit(aes_mod_exit);
+
+MODULE_DESCRIPTION("Synchronous AES in CCM mode using ARMv8 Crypto Extensions");
+MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("ccm(aes)");