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Date: Thu, 11 Jan 2024 13:33:05 +0100
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Subject: [PATCH 2/8] crypto: arm64/aes-ccm - Keep NEON enabled during skcipher walk
From: Ard Biesheuvel <ardb+git@google.com>
To: linux-crypto@vger.kernel.org
Cc: ebiggers@kernel.org, herbert@gondor.apana.org.au, 
	Ard Biesheuvel <ardb@kernel.org>
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From: Ard Biesheuvel <ardb@kernel.org>

Now that kernel mode NEON no longer disables preemption, we no longer
have to take care to disable and re-enable use of the NEON when calling
into the skcipher walk API. So just keep it enabled until done.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm64/crypto/aes-ce-ccm-glue.c | 22 +++++++++-----------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/arch/arm64/crypto/aes-ce-ccm-glue.c b/arch/arm64/crypto/aes-ce-ccm-glue.c
index c4f14415f5f0..b177ebea7d09 100644
--- a/arch/arm64/crypto/aes-ce-ccm-glue.c
+++ b/arch/arm64/crypto/aes-ce-ccm-glue.c
@@ -182,17 +182,16 @@ static int ccm_encrypt(struct aead_request *req)
 		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();
 		}
 	} while (walk.nbytes);
 
+	kernel_neon_end();
+
+	if (unlikely(err))
+		return err;
+
 	/* copy authtag to end of dst */
 	scatterwalk_map_and_copy(mac, req->dst, req->assoclen + req->cryptlen,
 				 crypto_aead_authsize(aead), 1);
@@ -240,17 +239,16 @@ static int ccm_decrypt(struct aead_request *req)
 		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();
 		}
 	} while (walk.nbytes);
 
+	kernel_neon_end();
+
+	if (unlikely(err))
+		return err;
+
 	/* compare calculated auth tag with the stored one */
 	scatterwalk_map_and_copy(buf, req->src,
 				 req->assoclen + req->cryptlen - authsize,
-- 
2.43.0.275.g3460e3d667-goog