[PATCH v5 0/5] running kernel mode SIMD with softirqs disabled

[PATCH v5 0/5] running kernel mode SIMD with softirqs disabled

[Ard Biesheuvel]

This is a follow-up to [0], but given that the arm64 architectural
pieces have been merged for arm64, the only remaining changes are crypto
specific. Therefore, the audience has been reduced to those people who
are somewhat more likely to care about these specifics.

The AEAD and skcipher APIs may only be called from task or softirq
context. This permits the arm64 AEAD and skcipher code to get rid of all
scalar fallbacks, given that on this architecture, softirqs are now no
longer served while the SIMD unit is being used in kernel mode, which
means that the scalar fallbacks are never needed. These are removed in
this series.

Changes since v4:
- drop skcipher_walk layer change to deal with zero sized walks
- drop aead/skcipher layer sanity checks on invocations from hardirq
  context
- add patch to clean up CCM a bit more after removing the SIMD code path

Changes since v3:
- clarify the nature of the issue addressed by patch #1, and apply the
  same fix to the skcipher walker
- update patches #2 and #3 so that the failures can be observed by the
  crypto stats code

[0] https://lore.kernel.org/linux-arm-kernel/20210302090118.30666-1-ardb@kernel.org/

Ard Biesheuvel (5):
  crypto: arm64/gcm-aes-ce - remove non-SIMD fallback path
  crypto: arm64/aes-neonbs - stop using SIMD helper for skciphers
  crypto: arm64/aes-ce - stop using SIMD helper for skciphers
  crypto: arm64/aes-ccm - remove non-SIMD fallback path
  crypto: arm64/aes-ccm - avoid by-ref argument for ce_aes_ccm_auth_data

 arch/arm64/crypto/Kconfig           |   6 -
 arch/arm64/crypto/aes-ce-ccm-core.S |  24 +--
 arch/arm64/crypto/aes-ce-ccm-glue.c | 194 ++++++------------
 arch/arm64/crypto/aes-glue.c        | 102 ++--------
 arch/arm64/crypto/aes-neonbs-glue.c | 122 +-----------
 arch/arm64/crypto/ghash-ce-glue.c   | 209 +++++---------------
 6 files changed, 141 insertions(+), 516 deletions(-)

-- 
2.20.1


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[PATCH v5 1/5] crypto: arm64/gcm-aes-ce - remove non-SIMD fallback path

[Ard Biesheuvel]

Now that kernel mode SIMD is guaranteed to be available when executing
in task or softirq context, we no longer need scalar fallbacks to use
when the NEON is unavailable. So get rid of them.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm64/crypto/ghash-ce-glue.c | 209 +++++---------------
 1 file changed, 51 insertions(+), 158 deletions(-)

diff --git a/arch/arm64/crypto/ghash-ce-glue.c b/arch/arm64/crypto/ghash-ce-glue.c
index 720cd3a58da3..15794fe21a0b 100644
--- a/arch/arm64/crypto/ghash-ce-glue.c
+++ b/arch/arm64/crypto/ghash-ce-glue.c
@@ -362,84 +362,36 @@ static int gcm_encrypt(struct aead_request *req)
 
 	err = skcipher_walk_aead_encrypt(&walk, req, false);
 
-	if (likely(crypto_simd_usable())) {
-		do {
-			const u8 *src = walk.src.virt.addr;
-			u8 *dst = walk.dst.virt.addr;
-			int nbytes = walk.nbytes;
-
-			tag = (u8 *)&lengths;
-
-			if (unlikely(nbytes > 0 && nbytes < AES_BLOCK_SIZE)) {
-				src = dst = memcpy(buf + sizeof(buf) - nbytes,
-						   src, nbytes);
-			} else if (nbytes < walk.total) {
-				nbytes &= ~(AES_BLOCK_SIZE - 1);
-				tag = NULL;
-			}
-
-			kernel_neon_begin();
-			pmull_gcm_encrypt(nbytes, dst, src, ctx->ghash_key.h,
-					  dg, iv, ctx->aes_key.key_enc, nrounds,
-					  tag);
-			kernel_neon_end();
-
-			if (unlikely(!nbytes))
-				break;
-
-			if (unlikely(nbytes > 0 && nbytes < AES_BLOCK_SIZE))
-				memcpy(walk.dst.virt.addr,
-				       buf + sizeof(buf) - nbytes, nbytes);
-
-			err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
-		} while (walk.nbytes);
-	} else {
-		while (walk.nbytes >= AES_BLOCK_SIZE) {
-			int blocks = walk.nbytes / AES_BLOCK_SIZE;
-			const u8 *src = walk.src.virt.addr;
-			u8 *dst = walk.dst.virt.addr;
-			int remaining = blocks;
-
-			do {
-				aes_encrypt(&ctx->aes_key, buf, iv);
-				crypto_xor_cpy(dst, src, buf, AES_BLOCK_SIZE);
-				crypto_inc(iv, AES_BLOCK_SIZE);
-
-				dst += AES_BLOCK_SIZE;
-				src += AES_BLOCK_SIZE;
-			} while (--remaining > 0);
-
-			ghash_do_update(blocks, dg, walk.dst.virt.addr,
-					&ctx->ghash_key, NULL);
-
-			err = skcipher_walk_done(&walk,
-						 walk.nbytes % AES_BLOCK_SIZE);
-		}
-
-		/* handle the tail */
-		if (walk.nbytes) {
-			aes_encrypt(&ctx->aes_key, buf, iv);
+	do {
+		const u8 *src = walk.src.virt.addr;
+		u8 *dst = walk.dst.virt.addr;
+		int nbytes = walk.nbytes;
 
-			crypto_xor_cpy(walk.dst.virt.addr, walk.src.virt.addr,
-				       buf, walk.nbytes);
+		tag = (u8 *)&lengths;
 
-			memcpy(buf, walk.dst.virt.addr, walk.nbytes);
-			memset(buf + walk.nbytes, 0, sizeof(buf) - walk.nbytes);
+		if (unlikely(nbytes > 0 && nbytes < AES_BLOCK_SIZE)) {
+			src = dst = memcpy(buf + sizeof(buf) - nbytes,
+					   src, nbytes);
+		} else if (nbytes < walk.total) {
+			nbytes &= ~(AES_BLOCK_SIZE - 1);
+			tag = NULL;
 		}
 
-		tag = (u8 *)&lengths;
-		ghash_do_update(1, dg, tag, &ctx->ghash_key,
-				walk.nbytes ? buf : NULL);
+		kernel_neon_begin();
+		pmull_gcm_encrypt(nbytes, dst, src, ctx->ghash_key.h,
+				  dg, iv, ctx->aes_key.key_enc, nrounds,
+				  tag);
+		kernel_neon_end();
 
-		if (walk.nbytes)
-			err = skcipher_walk_done(&walk, 0);
+		if (unlikely(!nbytes))
+			break;
 
-		put_unaligned_be64(dg[1], tag);
-		put_unaligned_be64(dg[0], tag + 8);
-		put_unaligned_be32(1, iv + GCM_IV_SIZE);
-		aes_encrypt(&ctx->aes_key, iv, iv);
-		crypto_xor(tag, iv, AES_BLOCK_SIZE);
-	}
+		if (unlikely(nbytes > 0 && nbytes < AES_BLOCK_SIZE))
+			memcpy(walk.dst.virt.addr,
+			       buf + sizeof(buf) - nbytes, nbytes);
+
+		err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
+	} while (walk.nbytes);
 
 	if (err)
 		return err;
@@ -464,6 +416,7 @@ static int gcm_decrypt(struct aead_request *req)
 	u64 dg[2] = {};
 	be128 lengths;
 	u8 *tag;
+	int ret;
 	int err;
 
 	lengths.a = cpu_to_be64(req->assoclen * 8);
@@ -481,101 +434,41 @@ static int gcm_decrypt(struct aead_request *req)
 
 	err = skcipher_walk_aead_decrypt(&walk, req, false);
 
-	if (likely(crypto_simd_usable())) {
-		int ret;
-
-		do {
-			const u8 *src = walk.src.virt.addr;
-			u8 *dst = walk.dst.virt.addr;
-			int nbytes = walk.nbytes;
-
-			tag = (u8 *)&lengths;
-
-			if (unlikely(nbytes > 0 && nbytes < AES_BLOCK_SIZE)) {
-				src = dst = memcpy(buf + sizeof(buf) - nbytes,
-						   src, nbytes);
-			} else if (nbytes < walk.total) {
-				nbytes &= ~(AES_BLOCK_SIZE - 1);
-				tag = NULL;
-			}
-
-			kernel_neon_begin();
-			ret = pmull_gcm_decrypt(nbytes, dst, src,
-						ctx->ghash_key.h,
-						dg, iv, ctx->aes_key.key_enc,
-						nrounds, tag, otag, authsize);
-			kernel_neon_end();
-
-			if (unlikely(!nbytes))
-				break;
-
-			if (unlikely(nbytes > 0 && nbytes < AES_BLOCK_SIZE))
-				memcpy(walk.dst.virt.addr,
-				       buf + sizeof(buf) - nbytes, nbytes);
-
-			err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
-		} while (walk.nbytes);
-
-		if (err)
-			return err;
-		if (ret)
-			return -EBADMSG;
-	} else {
-		while (walk.nbytes >= AES_BLOCK_SIZE) {
-			int blocks = walk.nbytes / AES_BLOCK_SIZE;
-			const u8 *src = walk.src.virt.addr;
-			u8 *dst = walk.dst.virt.addr;
-
-			ghash_do_update(blocks, dg, walk.src.virt.addr,
-					&ctx->ghash_key, NULL);
-
-			do {
-				aes_encrypt(&ctx->aes_key, buf, iv);
-				crypto_xor_cpy(dst, src, buf, AES_BLOCK_SIZE);
-				crypto_inc(iv, AES_BLOCK_SIZE);
-
-				dst += AES_BLOCK_SIZE;
-				src += AES_BLOCK_SIZE;
-			} while (--blocks > 0);
+	do {
+		const u8 *src = walk.src.virt.addr;
+		u8 *dst = walk.dst.virt.addr;
+		int nbytes = walk.nbytes;
 
-			err = skcipher_walk_done(&walk,
-						 walk.nbytes % AES_BLOCK_SIZE);
-		}
+		tag = (u8 *)&lengths;
 
-		/* handle the tail */
-		if (walk.nbytes) {
-			memcpy(buf, walk.src.virt.addr, walk.nbytes);
-			memset(buf + walk.nbytes, 0, sizeof(buf) - walk.nbytes);
+		if (unlikely(nbytes > 0 && nbytes < AES_BLOCK_SIZE)) {
+			src = dst = memcpy(buf + sizeof(buf) - nbytes,
+					   src, nbytes);
+		} else if (nbytes < walk.total) {
+			nbytes &= ~(AES_BLOCK_SIZE - 1);
+			tag = NULL;
 		}
 
-		tag = (u8 *)&lengths;
-		ghash_do_update(1, dg, tag, &ctx->ghash_key,
-				walk.nbytes ? buf : NULL);
-
-		if (walk.nbytes) {
-			aes_encrypt(&ctx->aes_key, buf, iv);
+		kernel_neon_begin();
+		ret = pmull_gcm_decrypt(nbytes, dst, src, ctx->ghash_key.h,
+					dg, iv, ctx->aes_key.key_enc,
+					nrounds, tag, otag, authsize);
+		kernel_neon_end();
 
-			crypto_xor_cpy(walk.dst.virt.addr, walk.src.virt.addr,
-				       buf, walk.nbytes);
+		if (unlikely(!nbytes))
+			break;
 
-			err = skcipher_walk_done(&walk, 0);
-		}
+		if (unlikely(nbytes > 0 && nbytes < AES_BLOCK_SIZE))
+			memcpy(walk.dst.virt.addr,
+			       buf + sizeof(buf) - nbytes, nbytes);
 
-		if (err)
-			return err;
+		err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
+	} while (walk.nbytes);
 
-		put_unaligned_be64(dg[1], tag);
-		put_unaligned_be64(dg[0], tag + 8);
-		put_unaligned_be32(1, iv + GCM_IV_SIZE);
-		aes_encrypt(&ctx->aes_key, iv, iv);
-		crypto_xor(tag, iv, AES_BLOCK_SIZE);
+	if (err)
+		return err;
 
-		if (crypto_memneq(tag, otag, authsize)) {
-			memzero_explicit(tag, AES_BLOCK_SIZE);
-			return -EBADMSG;
-		}
-	}
-	return 0;
+	return ret ? -EBADMSG : 0;
 }
 
 static struct aead_alg gcm_aes_alg = {
-- 
2.20.1


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Re: [PATCH v5 1/5] crypto: arm64/gcm-aes-ce - remove non-SIMD fallback path

[Eric Biggers]

On Fri, May 21, 2021 at 12:20:49PM +0200, Ard Biesheuvel wrote:
> Now that kernel mode SIMD is guaranteed to be available when executing
> in task or softirq context, we no longer need scalar fallbacks to use
> when the NEON is unavailable. So get rid of them.
> 
> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
> ---
>  arch/arm64/crypto/ghash-ce-glue.c | 209 +++++---------------
>  1 file changed, 51 insertions(+), 158 deletions(-)

Reviewed-by: Eric Biggers <ebiggers@google.com>

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[PATCH v5 2/5] crypto: arm64/aes-neonbs - stop using SIMD helper for skciphers

[Ard Biesheuvel]

Calls into the skcipher API can only occur from contexts where the SIMD
unit is available, so there is no need for the SIMD helper.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm64/crypto/Kconfig           |   2 -
 arch/arm64/crypto/aes-neonbs-glue.c | 122 ++------------------
 2 files changed, 9 insertions(+), 115 deletions(-)

diff --git a/arch/arm64/crypto/Kconfig b/arch/arm64/crypto/Kconfig
index b8eb0453123d..ed1e8cadeb3a 100644
--- a/arch/arm64/crypto/Kconfig
+++ b/arch/arm64/crypto/Kconfig
@@ -122,8 +122,6 @@ config CRYPTO_AES_ARM64_BS
 	depends on KERNEL_MODE_NEON
 	select CRYPTO_SKCIPHER
 	select CRYPTO_AES_ARM64_NEON_BLK
-	select CRYPTO_AES_ARM64
 	select CRYPTO_LIB_AES
-	select CRYPTO_SIMD
 
 endif
diff --git a/arch/arm64/crypto/aes-neonbs-glue.c b/arch/arm64/crypto/aes-neonbs-glue.c
index fb507d569922..8df6ad8cb09d 100644
--- a/arch/arm64/crypto/aes-neonbs-glue.c
+++ b/arch/arm64/crypto/aes-neonbs-glue.c
@@ -63,11 +63,6 @@ struct aesbs_cbc_ctx {
 	u32			enc[AES_MAX_KEYLENGTH_U32];
 };
 
-struct aesbs_ctr_ctx {
-	struct aesbs_ctx	key;		/* must be first member */
-	struct crypto_aes_ctx	fallback;
-};
-
 struct aesbs_xts_ctx {
 	struct aesbs_ctx	key;
 	u32			twkey[AES_MAX_KEYLENGTH_U32];
@@ -207,25 +202,6 @@ static int cbc_decrypt(struct skcipher_request *req)
 	return err;
 }
 
-static int aesbs_ctr_setkey_sync(struct crypto_skcipher *tfm, const u8 *in_key,
-				 unsigned int key_len)
-{
-	struct aesbs_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
-	int err;
-
-	err = aes_expandkey(&ctx->fallback, in_key, key_len);
-	if (err)
-		return err;
-
-	ctx->key.rounds = 6 + key_len / 4;
-
-	kernel_neon_begin();
-	aesbs_convert_key(ctx->key.rk, ctx->fallback.key_enc, ctx->key.rounds);
-	kernel_neon_end();
-
-	return 0;
-}
-
 static int ctr_encrypt(struct skcipher_request *req)
 {
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
@@ -292,29 +268,6 @@ static int aesbs_xts_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
 	return aesbs_setkey(tfm, in_key, key_len);
 }
 
-static void ctr_encrypt_one(struct crypto_skcipher *tfm, const u8 *src, u8 *dst)
-{
-	struct aesbs_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
-	unsigned long flags;
-
-	/*
-	 * Temporarily disable interrupts to avoid races where
-	 * cachelines are evicted when the CPU is interrupted
-	 * to do something else.
-	 */
-	local_irq_save(flags);
-	aes_encrypt(&ctx->fallback, dst, src);
-	local_irq_restore(flags);
-}
-
-static int ctr_encrypt_sync(struct skcipher_request *req)
-{
-	if (!crypto_simd_usable())
-		return crypto_ctr_encrypt_walk(req, ctr_encrypt_one);
-
-	return ctr_encrypt(req);
-}
-
 static int __xts_crypt(struct skcipher_request *req, bool encrypt,
 		       void (*fn)(u8 out[], u8 const in[], u8 const rk[],
 				  int rounds, int blocks, u8 iv[]))
@@ -431,13 +384,12 @@ static int xts_decrypt(struct skcipher_request *req)
 }
 
 static struct skcipher_alg aes_algs[] = { {
-	.base.cra_name		= "__ecb(aes)",
-	.base.cra_driver_name	= "__ecb-aes-neonbs",
+	.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,
@@ -446,13 +398,12 @@ static struct skcipher_alg aes_algs[] = { {
 	.encrypt		= ecb_encrypt,
 	.decrypt		= ecb_decrypt,
 }, {
-	.base.cra_name		= "__cbc(aes)",
-	.base.cra_driver_name	= "__cbc-aes-neonbs",
+	.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,
@@ -462,13 +413,12 @@ static struct skcipher_alg aes_algs[] = { {
 	.encrypt		= cbc_encrypt,
 	.decrypt		= cbc_decrypt,
 }, {
-	.base.cra_name		= "__ctr(aes)",
-	.base.cra_driver_name	= "__ctr-aes-neonbs",
+	.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,
@@ -479,29 +429,12 @@ static struct skcipher_alg aes_algs[] = { {
 	.encrypt		= ctr_encrypt,
 	.decrypt		= ctr_encrypt,
 }, {
-	.base.cra_name		= "ctr(aes)",
-	.base.cra_driver_name	= "ctr-aes-neonbs",
-	.base.cra_priority	= 250 - 1,
-	.base.cra_blocksize	= 1,
-	.base.cra_ctxsize	= sizeof(struct aesbs_ctr_ctx),
-	.base.cra_module	= THIS_MODULE,
-
-	.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_ctr_setkey_sync,
-	.encrypt		= ctr_encrypt_sync,
-	.decrypt		= ctr_encrypt_sync,
-}, {
-	.base.cra_name		= "__xts(aes)",
-	.base.cra_driver_name	= "__xts-aes-neonbs",
+	.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,
@@ -512,54 +445,17 @@ static struct skcipher_alg aes_algs[] = { {
 	.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 (!cpu_have_named_feature(ASIMD))
 		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;
+	return crypto_register_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
 }
 
 module_init(aes_init);
-- 
2.20.1


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Re: [PATCH v5 2/5] crypto: arm64/aes-neonbs - stop using SIMD helper for skciphers

[Eric Biggers]

On Fri, May 21, 2021 at 12:20:50PM +0200, Ard Biesheuvel wrote:
> Calls into the skcipher API can only occur from contexts where the SIMD
> unit is available, so there is no need for the SIMD helper.
> 
> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
> ---
>  arch/arm64/crypto/Kconfig           |   2 -
>  arch/arm64/crypto/aes-neonbs-glue.c | 122 ++------------------
>  2 files changed, 9 insertions(+), 115 deletions(-)

Reviewed-by: Eric Biggers <ebiggers@google.com>

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[PATCH v5 3/5] crypto: arm64/aes-ce - stop using SIMD helper for skciphers

[Ard Biesheuvel]

Calls into the skcipher API can only occur from contexts where the SIMD
unit is available, so there is no need for the SIMD helper.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm64/crypto/Kconfig    |   4 -
 arch/arm64/crypto/aes-glue.c | 102 +++-----------------
 2 files changed, 13 insertions(+), 93 deletions(-)

diff --git a/arch/arm64/crypto/Kconfig b/arch/arm64/crypto/Kconfig
index ed1e8cadeb3a..454621a20eaa 100644
--- a/arch/arm64/crypto/Kconfig
+++ b/arch/arm64/crypto/Kconfig
@@ -88,16 +88,12 @@ config CRYPTO_AES_ARM64_CE_BLK
 	depends on KERNEL_MODE_NEON
 	select CRYPTO_SKCIPHER
 	select CRYPTO_AES_ARM64_CE
-	select CRYPTO_AES_ARM64
-	select CRYPTO_SIMD
 
 config CRYPTO_AES_ARM64_NEON_BLK
 	tristate "AES in ECB/CBC/CTR/XTS modes using NEON instructions"
 	depends on KERNEL_MODE_NEON
 	select CRYPTO_SKCIPHER
-	select CRYPTO_AES_ARM64
 	select CRYPTO_LIB_AES
-	select CRYPTO_SIMD
 
 config CRYPTO_CHACHA20_NEON
 	tristate "ChaCha20, XChaCha20, and XChaCha12 stream ciphers using NEON instructions"
diff --git a/arch/arm64/crypto/aes-glue.c b/arch/arm64/crypto/aes-glue.c
index 17e735931a0c..30b7cc6a7079 100644
--- a/arch/arm64/crypto/aes-glue.c
+++ b/arch/arm64/crypto/aes-glue.c
@@ -444,7 +444,7 @@ static int __maybe_unused essiv_cbc_decrypt(struct skcipher_request *req)
 	return err ?: cbc_decrypt_walk(req, &walk);
 }
 
-static int ctr_encrypt(struct skcipher_request *req)
+static int __maybe_unused ctr_encrypt(struct skcipher_request *req)
 {
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
@@ -485,29 +485,6 @@ static int ctr_encrypt(struct skcipher_request *req)
 	return err;
 }
 
-static void ctr_encrypt_one(struct crypto_skcipher *tfm, const u8 *src, u8 *dst)
-{
-	const struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
-	unsigned long flags;
-
-	/*
-	 * Temporarily disable interrupts to avoid races where
-	 * cachelines are evicted when the CPU is interrupted
-	 * to do something else.
-	 */
-	local_irq_save(flags);
-	aes_encrypt(ctx, dst, src);
-	local_irq_restore(flags);
-}
-
-static int __maybe_unused ctr_encrypt_sync(struct skcipher_request *req)
-{
-	if (!crypto_simd_usable())
-		return crypto_ctr_encrypt_walk(req, ctr_encrypt_one);
-
-	return ctr_encrypt(req);
-}
-
 static int __maybe_unused xts_encrypt(struct skcipher_request *req)
 {
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
@@ -656,10 +633,9 @@ static int __maybe_unused xts_decrypt(struct skcipher_request *req)
 static struct skcipher_alg aes_algs[] = { {
 #if defined(USE_V8_CRYPTO_EXTENSIONS) || !IS_ENABLED(CONFIG_CRYPTO_AES_ARM64_BS)
 	.base = {
-		.cra_name		= "__ecb(aes)",
-		.cra_driver_name	= "__ecb-aes-" MODE,
+		.cra_name		= "ecb(aes)",
+		.cra_driver_name	= "ecb-aes-" MODE,
 		.cra_priority		= PRIO,
-		.cra_flags		= CRYPTO_ALG_INTERNAL,
 		.cra_blocksize		= AES_BLOCK_SIZE,
 		.cra_ctxsize		= sizeof(struct crypto_aes_ctx),
 		.cra_module		= THIS_MODULE,
@@ -671,10 +647,9 @@ static struct skcipher_alg aes_algs[] = { {
 	.decrypt	= ecb_decrypt,
 }, {
 	.base = {
-		.cra_name		= "__cbc(aes)",
-		.cra_driver_name	= "__cbc-aes-" MODE,
+		.cra_name		= "cbc(aes)",
+		.cra_driver_name	= "cbc-aes-" MODE,
 		.cra_priority		= PRIO,
-		.cra_flags		= CRYPTO_ALG_INTERNAL,
 		.cra_blocksize		= AES_BLOCK_SIZE,
 		.cra_ctxsize		= sizeof(struct crypto_aes_ctx),
 		.cra_module		= THIS_MODULE,
@@ -687,10 +662,9 @@ static struct skcipher_alg aes_algs[] = { {
 	.decrypt	= cbc_decrypt,
 }, {
 	.base = {
-		.cra_name		= "__ctr(aes)",
-		.cra_driver_name	= "__ctr-aes-" MODE,
+		.cra_name		= "ctr(aes)",
+		.cra_driver_name	= "ctr-aes-" MODE,
 		.cra_priority		= PRIO,
-		.cra_flags		= CRYPTO_ALG_INTERNAL,
 		.cra_blocksize		= 1,
 		.cra_ctxsize		= sizeof(struct crypto_aes_ctx),
 		.cra_module		= THIS_MODULE,
@@ -704,26 +678,9 @@ static struct skcipher_alg aes_algs[] = { {
 	.decrypt	= ctr_encrypt,
 }, {
 	.base = {
-		.cra_name		= "ctr(aes)",
-		.cra_driver_name	= "ctr-aes-" MODE,
-		.cra_priority		= PRIO - 1,
-		.cra_blocksize		= 1,
-		.cra_ctxsize		= sizeof(struct crypto_aes_ctx),
-		.cra_module		= THIS_MODULE,
-	},
-	.min_keysize	= AES_MIN_KEY_SIZE,
-	.max_keysize	= AES_MAX_KEY_SIZE,
-	.ivsize		= AES_BLOCK_SIZE,
-	.chunksize	= AES_BLOCK_SIZE,
-	.setkey		= skcipher_aes_setkey,
-	.encrypt	= ctr_encrypt_sync,
-	.decrypt	= ctr_encrypt_sync,
-}, {
-	.base = {
-		.cra_name		= "__xts(aes)",
-		.cra_driver_name	= "__xts-aes-" MODE,
+		.cra_name		= "xts(aes)",
+		.cra_driver_name	= "xts-aes-" MODE,
 		.cra_priority		= PRIO,
-		.cra_flags		= CRYPTO_ALG_INTERNAL,
 		.cra_blocksize		= AES_BLOCK_SIZE,
 		.cra_ctxsize		= sizeof(struct crypto_aes_xts_ctx),
 		.cra_module		= THIS_MODULE,
@@ -738,10 +695,9 @@ static struct skcipher_alg aes_algs[] = { {
 }, {
 #endif
 	.base = {
-		.cra_name		= "__cts(cbc(aes))",
-		.cra_driver_name	= "__cts-cbc-aes-" MODE,
+		.cra_name		= "cts(cbc(aes))",
+		.cra_driver_name	= "cts-cbc-aes-" MODE,
 		.cra_priority		= PRIO,
-		.cra_flags		= CRYPTO_ALG_INTERNAL,
 		.cra_blocksize		= AES_BLOCK_SIZE,
 		.cra_ctxsize		= sizeof(struct crypto_aes_ctx),
 		.cra_module		= THIS_MODULE,
@@ -755,10 +711,9 @@ static struct skcipher_alg aes_algs[] = { {
 	.decrypt	= cts_cbc_decrypt,
 }, {
 	.base = {
-		.cra_name		= "__essiv(cbc(aes),sha256)",
-		.cra_driver_name	= "__essiv-cbc-aes-sha256-" MODE,
+		.cra_name		= "essiv(cbc(aes),sha256)",
+		.cra_driver_name	= "essiv-cbc-aes-sha256-" MODE,
 		.cra_priority		= PRIO + 1,
-		.cra_flags		= CRYPTO_ALG_INTERNAL,
 		.cra_blocksize		= AES_BLOCK_SIZE,
 		.cra_ctxsize		= sizeof(struct crypto_aes_essiv_cbc_ctx),
 		.cra_module		= THIS_MODULE,
@@ -997,28 +952,15 @@ static struct shash_alg mac_algs[] = { {
 	.descsize		= sizeof(struct mac_desc_ctx),
 } };
 
-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_shashes(mac_algs, ARRAY_SIZE(mac_algs));
 	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;
 
 	err = crypto_register_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
 	if (err)
@@ -1028,26 +970,8 @@ static int __init aes_init(void)
 	if (err)
 		goto unregister_ciphers;
 
-	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;
 unregister_ciphers:
 	crypto_unregister_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
 	return err;
-- 
2.20.1


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Re: [PATCH v5 3/5] crypto: arm64/aes-ce - stop using SIMD helper for skciphers

[Eric Biggers]

On Fri, May 21, 2021 at 12:20:51PM +0200, Ard Biesheuvel wrote:
> Calls into the skcipher API can only occur from contexts where the SIMD
> unit is available, so there is no need for the SIMD helper.
> 
> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
> ---
>  arch/arm64/crypto/Kconfig    |   4 -
>  arch/arm64/crypto/aes-glue.c | 102 +++-----------------
>  2 files changed, 13 insertions(+), 93 deletions(-)

Reviewed-by: Eric Biggers <ebiggers@google.com>

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[PATCH v5 4/5] crypto: arm64/aes-ccm - remove non-SIMD fallback path

[Ard Biesheuvel]

AES/CCM on arm64 is implemented as a synchronous AEAD, and so it is
guaranteed by the API that it is only invoked in task or softirq
context. Since softirqs are now only handled when the SIMD is not
being used in the task context that was interrupted to service the
softirq, we no longer need a fallback path. Let's remove it.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm64/crypto/aes-ce-ccm-core.S |   1 +
 arch/arm64/crypto/aes-ce-ccm-glue.c | 181 ++++++--------------
 2 files changed, 53 insertions(+), 129 deletions(-)

diff --git a/arch/arm64/crypto/aes-ce-ccm-core.S b/arch/arm64/crypto/aes-ce-ccm-core.S
index 99a028e298ed..8adff299fcd3 100644
--- a/arch/arm64/crypto/aes-ce-ccm-core.S
+++ b/arch/arm64/crypto/aes-ce-ccm-core.S
@@ -124,6 +124,7 @@ SYM_FUNC_START(ce_aes_ccm_final)
 SYM_FUNC_END(ce_aes_ccm_final)
 
 	.macro	aes_ccm_do_crypt,enc
+	cbz	x2, 5f
 	ldr	x8, [x6, #8]			/* load lower ctr */
 	ld1	{v0.16b}, [x5]			/* load mac */
 CPU_LE(	rev	x8, x8			)	/* keep swabbed ctr in reg */
diff --git a/arch/arm64/crypto/aes-ce-ccm-glue.c b/arch/arm64/crypto/aes-ce-ccm-glue.c
index f6d19b0dc893..8effd18429ac 100644
--- a/arch/arm64/crypto/aes-ce-ccm-glue.c
+++ b/arch/arm64/crypto/aes-ce-ccm-glue.c
@@ -99,36 +99,8 @@ static int ccm_init_mac(struct aead_request *req, u8 maciv[], u32 msglen)
 static void ccm_update_mac(struct crypto_aes_ctx *key, u8 mac[], u8 const in[],
 			   u32 abytes, u32 *macp)
 {
-	if (crypto_simd_usable()) {
-		kernel_neon_begin();
-		ce_aes_ccm_auth_data(mac, in, abytes, macp, key->key_enc,
-				     num_rounds(key));
-		kernel_neon_end();
-	} else {
-		if (*macp > 0 && *macp < AES_BLOCK_SIZE) {
-			int added = min(abytes, AES_BLOCK_SIZE - *macp);
-
-			crypto_xor(&mac[*macp], in, added);
-
-			*macp += added;
-			in += added;
-			abytes -= added;
-		}
-
-		while (abytes >= AES_BLOCK_SIZE) {
-			aes_encrypt(key, mac, mac);
-			crypto_xor(mac, in, AES_BLOCK_SIZE);
-
-			in += AES_BLOCK_SIZE;
-			abytes -= AES_BLOCK_SIZE;
-		}
-
-		if (abytes > 0) {
-			aes_encrypt(key, mac, mac);
-			crypto_xor(mac, in, abytes);
-			*macp = abytes;
-		}
-	}
+	ce_aes_ccm_auth_data(mac, in, abytes, macp, key->key_enc,
+			     num_rounds(key));
 }
 
 static void ccm_calculate_auth_mac(struct aead_request *req, u8 mac[])
@@ -171,54 +143,6 @@ static void ccm_calculate_auth_mac(struct aead_request *req, u8 mac[])
 	} while (len);
 }
 
-static int ccm_crypt_fallback(struct skcipher_walk *walk, u8 mac[], u8 iv0[],
-			      struct crypto_aes_ctx *ctx, bool enc)
-{
-	u8 buf[AES_BLOCK_SIZE];
-	int err = 0;
-
-	while (walk->nbytes) {
-		int blocks = walk->nbytes / AES_BLOCK_SIZE;
-		u32 tail = walk->nbytes % AES_BLOCK_SIZE;
-		u8 *dst = walk->dst.virt.addr;
-		u8 *src = walk->src.virt.addr;
-		u32 nbytes = walk->nbytes;
-
-		if (nbytes == walk->total && tail > 0) {
-			blocks++;
-			tail = 0;
-		}
-
-		do {
-			u32 bsize = AES_BLOCK_SIZE;
-
-			if (nbytes < AES_BLOCK_SIZE)
-				bsize = nbytes;
-
-			crypto_inc(walk->iv, AES_BLOCK_SIZE);
-			aes_encrypt(ctx, buf, walk->iv);
-			aes_encrypt(ctx, mac, mac);
-			if (enc)
-				crypto_xor(mac, src, bsize);
-			crypto_xor_cpy(dst, src, buf, bsize);
-			if (!enc)
-				crypto_xor(mac, dst, bsize);
-			dst += bsize;
-			src += bsize;
-			nbytes -= bsize;
-		} while (--blocks);
-
-		err = skcipher_walk_done(walk, tail);
-	}
-
-	if (!err) {
-		aes_encrypt(ctx, buf, iv0);
-		aes_encrypt(ctx, mac, mac);
-		crypto_xor(mac, buf, AES_BLOCK_SIZE);
-	}
-	return err;
-}
-
 static int ccm_encrypt(struct aead_request *req)
 {
 	struct crypto_aead *aead = crypto_aead_reqtfm(req);
@@ -233,41 +157,41 @@ static int ccm_encrypt(struct aead_request *req)
 	if (err)
 		return err;
 
-	if (req->assoclen)
-		ccm_calculate_auth_mac(req, mac);
-
 	/* preserve the original iv for the final round */
 	memcpy(buf, req->iv, AES_BLOCK_SIZE);
 
 	err = skcipher_walk_aead_encrypt(&walk, req, false);
+	if (unlikely(err))
+		return err;
 
-	if (crypto_simd_usable()) {
-		while (walk.nbytes) {
-			u32 tail = walk.nbytes % AES_BLOCK_SIZE;
+	kernel_neon_begin();
 
-			if (walk.nbytes == walk.total)
-				tail = 0;
+	if (req->assoclen)
+		ccm_calculate_auth_mac(req, mac);
 
-			kernel_neon_begin();
-			ce_aes_ccm_encrypt(walk.dst.virt.addr,
-					   walk.src.virt.addr,
-					   walk.nbytes - tail, ctx->key_enc,
-					   num_rounds(ctx), mac, walk.iv);
-			kernel_neon_end();
+	do {
+		u32 tail = walk.nbytes % AES_BLOCK_SIZE;
 
+		if (walk.nbytes == walk.total)
+			tail = 0;
+
+		ce_aes_ccm_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
+				   walk.nbytes - tail, ctx->key_enc,
+				   num_rounds(ctx), mac, walk.iv);
+
+		if (walk.nbytes == walk.total)
+			ce_aes_ccm_final(mac, buf, ctx->key_enc, num_rounds(ctx));
+
+		kernel_neon_end();
+
+		if (walk.nbytes) {
 			err = skcipher_walk_done(&walk, tail);
+			if (unlikely(err))
+				return err;
+			if (unlikely(walk.nbytes))
+				kernel_neon_begin();
 		}
-		if (!err) {
-			kernel_neon_begin();
-			ce_aes_ccm_final(mac, buf, ctx->key_enc,
-					 num_rounds(ctx));
-			kernel_neon_end();
-		}
-	} else {
-		err = ccm_crypt_fallback(&walk, mac, buf, ctx, true);
-	}
-	if (err)
-		return err;
+	} while (walk.nbytes);
 
 	/* copy authtag to end of dst */
 	scatterwalk_map_and_copy(mac, req->dst, req->assoclen + req->cryptlen,
@@ -291,42 +215,41 @@ static int ccm_decrypt(struct aead_request *req)
 	if (err)
 		return err;
 
-	if (req->assoclen)
-		ccm_calculate_auth_mac(req, mac);
-
 	/* preserve the original iv for the final round */
 	memcpy(buf, req->iv, AES_BLOCK_SIZE);
 
 	err = skcipher_walk_aead_decrypt(&walk, req, false);
+	if (unlikely(err))
+		return err;
 
-	if (crypto_simd_usable()) {
-		while (walk.nbytes) {
-			u32 tail = walk.nbytes % AES_BLOCK_SIZE;
+	kernel_neon_begin();
 
-			if (walk.nbytes == walk.total)
-				tail = 0;
+	if (req->assoclen)
+		ccm_calculate_auth_mac(req, mac);
+
+	do {
+		u32 tail = walk.nbytes % AES_BLOCK_SIZE;
+
+		if (walk.nbytes == walk.total)
+			tail = 0;
+
+		ce_aes_ccm_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
+				   walk.nbytes - tail, ctx->key_enc,
+				   num_rounds(ctx), mac, walk.iv);
 
-			kernel_neon_begin();
-			ce_aes_ccm_decrypt(walk.dst.virt.addr,
-					   walk.src.virt.addr,
-					   walk.nbytes - tail, ctx->key_enc,
-					   num_rounds(ctx), mac, walk.iv);
-			kernel_neon_end();
+		if (walk.nbytes == walk.total)
+			ce_aes_ccm_final(mac, buf, ctx->key_enc, num_rounds(ctx));
 
+		kernel_neon_end();
+
+		if (walk.nbytes) {
 			err = skcipher_walk_done(&walk, tail);
+			if (unlikely(err))
+				return err;
+			if (unlikely(walk.nbytes))
+				kernel_neon_begin();
 		}
-		if (!err) {
-			kernel_neon_begin();
-			ce_aes_ccm_final(mac, buf, ctx->key_enc,
-					 num_rounds(ctx));
-			kernel_neon_end();
-		}
-	} else {
-		err = ccm_crypt_fallback(&walk, mac, buf, ctx, false);
-	}
-
-	if (err)
-		return err;
+	} while (walk.nbytes);
 
 	/* compare calculated auth tag with the stored one */
 	scatterwalk_map_and_copy(buf, req->src,
-- 
2.20.1


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Re: [PATCH v5 4/5] crypto: arm64/aes-ccm - remove non-SIMD fallback path

[Eric Biggers]

On Fri, May 21, 2021 at 12:20:52PM +0200, Ard Biesheuvel wrote:
> AES/CCM on arm64 is implemented as a synchronous AEAD, and so it is
> guaranteed by the API that it is only invoked in task or softirq
> context. Since softirqs are now only handled when the SIMD is not
> being used in the task context that was interrupted to service the
> softirq, we no longer need a fallback path. Let's remove it.
> 
> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
> ---
>  arch/arm64/crypto/aes-ce-ccm-core.S |   1 +
>  arch/arm64/crypto/aes-ce-ccm-glue.c | 181 ++++++--------------
>  2 files changed, 53 insertions(+), 129 deletions(-)

This doesn't just remove the no-SIMD fallback, but it also does some
refactoring.  Notably, it starts to process all the authenticated data in one
kernel_neon_begin() / kernel_neon_end() pair rather than many.  Can you explain
why that is okay now when previously it wasn't, and also split this into two
separate commits?

- Eric

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Re: [PATCH v5 4/5] crypto: arm64/aes-ccm - remove non-SIMD fallback path

[Ard Biesheuvel]

On Mon, 24 May 2021 at 23:51, Eric Biggers <ebiggers@kernel.org> wrote:
>
> On Fri, May 21, 2021 at 12:20:52PM +0200, Ard Biesheuvel wrote:
> > AES/CCM on arm64 is implemented as a synchronous AEAD, and so it is
> > guaranteed by the API that it is only invoked in task or softirq
> > context. Since softirqs are now only handled when the SIMD is not
> > being used in the task context that was interrupted to service the
> > softirq, we no longer need a fallback path. Let's remove it.
> >
> > Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
> > ---
> >  arch/arm64/crypto/aes-ce-ccm-core.S |   1 +
> >  arch/arm64/crypto/aes-ce-ccm-glue.c | 181 ++++++--------------
> >  2 files changed, 53 insertions(+), 129 deletions(-)
>
> This doesn't just remove the no-SIMD fallback, but it also does some
> refactoring.  Notably, it starts to process all the authenticated data in one
> kernel_neon_begin() / kernel_neon_end() pair rather than many.  Can you explain
> why that is okay now when previously it wasn't, and also split this into two
> separate commits?
>

OK.

For the record, the reason is that, even though kernel_neon_begin/end
are reasonably cheap these days, the common case for CCM (given its
use in networking context) is for the auth/encrypt/finalize routines
to each be called a single time, without any potentially sleeping
calls into the skcipher walk layer in between. Now that we are doing
more work in there (disable softirq processing as well as preemption),
it was a suitable occasion to do some refactoring that I have had on
my list for a while now.

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[PATCH v5 5/5] crypto: arm64/aes-ccm - avoid by-ref argument for ce_aes_ccm_auth_data

[Ard Biesheuvel]

With the SIMD code path removed, we can clean up the CCM auth-only path
a bit further, by passing the 'macp' input buffer pointer by value,
rather than by reference, and taking the output value from the
function's return value.

This way, the compiler is no longer forced to allocate macp on the
stack. This is not expected to make any difference in practice, it just
makes for slightly cleaner code.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm64/crypto/aes-ce-ccm-core.S | 23 ++++++++++----------
 arch/arm64/crypto/aes-ce-ccm-glue.c | 17 +++++----------
 2 files changed, 17 insertions(+), 23 deletions(-)

diff --git a/arch/arm64/crypto/aes-ce-ccm-core.S b/arch/arm64/crypto/aes-ce-ccm-core.S
index 8adff299fcd3..b03f7f71f893 100644
--- a/arch/arm64/crypto/aes-ce-ccm-core.S
+++ b/arch/arm64/crypto/aes-ce-ccm-core.S
@@ -12,22 +12,21 @@
 	.arch	armv8-a+crypto
 
 	/*
-	 * void ce_aes_ccm_auth_data(u8 mac[], u8 const in[], u32 abytes,
-	 *			     u32 *macp, u8 const rk[], u32 rounds);
+	 * u32 ce_aes_ccm_auth_data(u8 mac[], u8 const in[], u32 abytes,
+	 *			    u32 macp, u8 const rk[], u32 rounds);
 	 */
 SYM_FUNC_START(ce_aes_ccm_auth_data)
-	ldr	w8, [x3]			/* leftover from prev round? */
 	ld1	{v0.16b}, [x0]			/* load mac */
-	cbz	w8, 1f
-	sub	w8, w8, #16
+	cbz	w3, 1f
+	sub	w3, w3, #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
+	add	w3, w3, #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
+	cbnz	w3, 0b
 	eor	v0.16b, v0.16b, v1.16b
 1:	ld1	{v3.4s}, [x4]			/* load first round key */
 	prfm	pldl1strm, [x1]
@@ -62,7 +61,7 @@ SYM_FUNC_START(ce_aes_ccm_auth_data)
 	beq	10f
 	adds	w2, w2, #16
 	beq	10f
-	mov	w8, w2
+	mov	w3, w2
 7:	ldrb	w7, [x1], #1
 	umov	w6, v0.b[0]
 	eor	w6, w6, w7
@@ -71,15 +70,15 @@ SYM_FUNC_START(ce_aes_ccm_auth_data)
 	beq	10f
 	ext	v0.16b, v0.16b, v0.16b, #1	/* rotate out the mac bytes */
 	b	7b
-8:	cbz	w8, 91f
-	mov	w7, w8
-	add	w8, w8, #16
+8:	cbz	w3, 91f
+	mov	w7, w3
+	add	w3, w3, #16
 9:	ext	v1.16b, v1.16b, v1.16b, #1
 	adds	w7, w7, #1
 	bne	9b
 91:	eor	v0.16b, v0.16b, v1.16b
 	st1	{v0.16b}, [x0]
-10:	str	w8, [x3]
+10:	mov	w0, w3
 	ret
 SYM_FUNC_END(ce_aes_ccm_auth_data)
 
diff --git a/arch/arm64/crypto/aes-ce-ccm-glue.c b/arch/arm64/crypto/aes-ce-ccm-glue.c
index 8effd18429ac..d4e87b4e348f 100644
--- a/arch/arm64/crypto/aes-ce-ccm-glue.c
+++ b/arch/arm64/crypto/aes-ce-ccm-glue.c
@@ -29,8 +29,8 @@ static int num_rounds(struct crypto_aes_ctx *ctx)
 	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 u32 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[],
@@ -96,13 +96,6 @@ static int ccm_init_mac(struct aead_request *req, u8 maciv[], u32 msglen)
 	return 0;
 }
 
-static void ccm_update_mac(struct crypto_aes_ctx *key, u8 mac[], u8 const in[],
-			   u32 abytes, u32 *macp)
-{
-	ce_aes_ccm_auth_data(mac, in, abytes, macp, key->key_enc,
-			     num_rounds(key));
-}
-
 static void ccm_calculate_auth_mac(struct aead_request *req, u8 mac[])
 {
 	struct crypto_aead *aead = crypto_aead_reqtfm(req);
@@ -122,7 +115,8 @@ static void ccm_calculate_auth_mac(struct aead_request *req, u8 mac[])
 		ltag.len = 6;
 	}
 
-	ccm_update_mac(ctx, mac, (u8 *)&ltag, ltag.len, &macp);
+	macp = ce_aes_ccm_auth_data(mac, (u8 *)&ltag, ltag.len, macp,
+				    ctx->key_enc, num_rounds(ctx));
 	scatterwalk_start(&walk, req->src);
 
 	do {
@@ -134,7 +128,8 @@ static void ccm_calculate_auth_mac(struct aead_request *req, u8 mac[])
 			n = scatterwalk_clamp(&walk, len);
 		}
 		p = scatterwalk_map(&walk);
-		ccm_update_mac(ctx, mac, p, n, &macp);
+		macp = ce_aes_ccm_auth_data(mac, p, n, macp, ctx->key_enc,
+					    num_rounds(ctx));
 		len -= n;
 
 		scatterwalk_unmap(p);
-- 
2.20.1


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Re: [PATCH v5 5/5] crypto: arm64/aes-ccm - avoid by-ref argument for ce_aes_ccm_auth_data

[Eric Biggers]

On Fri, May 21, 2021 at 12:20:53PM +0200, Ard Biesheuvel wrote:
> With the SIMD code path removed, we can clean up the CCM auth-only path
> a bit further, by passing the 'macp' input buffer pointer by value,
> rather than by reference, and taking the output value from the
> function's return value.
> 
> This way, the compiler is no longer forced to allocate macp on the
> stack. This is not expected to make any difference in practice, it just
> makes for slightly cleaner code.
> 
> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
> ---
>  arch/arm64/crypto/aes-ce-ccm-core.S | 23 ++++++++++----------
>  arch/arm64/crypto/aes-ce-ccm-glue.c | 17 +++++----------
>  2 files changed, 17 insertions(+), 23 deletions(-)
> 
> diff --git a/arch/arm64/crypto/aes-ce-ccm-core.S b/arch/arm64/crypto/aes-ce-ccm-core.S
> index 8adff299fcd3..b03f7f71f893 100644
> --- a/arch/arm64/crypto/aes-ce-ccm-core.S
> +++ b/arch/arm64/crypto/aes-ce-ccm-core.S
> @@ -12,22 +12,21 @@
>  	.arch	armv8-a+crypto
>  
>  	/*
> -	 * void ce_aes_ccm_auth_data(u8 mac[], u8 const in[], u32 abytes,
> -	 *			     u32 *macp, u8 const rk[], u32 rounds);
> +	 * u32 ce_aes_ccm_auth_data(u8 mac[], u8 const in[], u32 abytes,
> +	 *			    u32 macp, u8 const rk[], u32 rounds);

How is this different from 'u8 mac[]' which is already one of the parameters?

- Eric

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Re: [PATCH v5 5/5] crypto: arm64/aes-ccm - avoid by-ref argument for ce_aes_ccm_auth_data

[Ard Biesheuvel]

On Mon, 24 May 2021 at 23:53, Eric Biggers <ebiggers@kernel.org> wrote:
>
> On Fri, May 21, 2021 at 12:20:53PM +0200, Ard Biesheuvel wrote:
> > With the SIMD code path removed, we can clean up the CCM auth-only path
> > a bit further, by passing the 'macp' input buffer pointer by value,
> > rather than by reference, and taking the output value from the
> > function's return value.
> >
> > This way, the compiler is no longer forced to allocate macp on the
> > stack. This is not expected to make any difference in practice, it just
> > makes for slightly cleaner code.
> >
> > Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
> > ---
> >  arch/arm64/crypto/aes-ce-ccm-core.S | 23 ++++++++++----------
> >  arch/arm64/crypto/aes-ce-ccm-glue.c | 17 +++++----------
> >  2 files changed, 17 insertions(+), 23 deletions(-)
> >
> > diff --git a/arch/arm64/crypto/aes-ce-ccm-core.S b/arch/arm64/crypto/aes-ce-ccm-core.S
> > index 8adff299fcd3..b03f7f71f893 100644
> > --- a/arch/arm64/crypto/aes-ce-ccm-core.S
> > +++ b/arch/arm64/crypto/aes-ce-ccm-core.S
> > @@ -12,22 +12,21 @@
> >       .arch   armv8-a+crypto
> >
> >       /*
> > -      * void ce_aes_ccm_auth_data(u8 mac[], u8 const in[], u32 abytes,
> > -      *                           u32 *macp, u8 const rk[], u32 rounds);
> > +      * u32 ce_aes_ccm_auth_data(u8 mac[], u8 const in[], u32 abytes,
> > +      *                          u32 macp, u8 const rk[], u32 rounds);
>
> How is this different from 'u8 mac[]' which is already one of the parameters?
>

mac[] is the combined digest/input buffer, and macp is the index into
it that keeps track on how much new input we have accumulated. I.e.,
instead of having a separate buffer of the same size, and accumulating
bytes until we can perform the XOR + AES transformation, the partial
input is accumulated into mac[] using XOR directly.

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