linux-kernel - [PATCH 1/5] crypto/arm64: aes-ce-ccm - Avoid pointless yield of the NEON unit

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Message-ID: <20250918063539.2640512-8-ardb+git@google.com>
Date: Thu, 18 Sep 2025 08:35:41 +0200
From: Ard Biesheuvel <ardb+git@...gle.com>
To: linux-arm-kernel@...ts.infradead.org
Cc: linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org, 
	herbert@...dor.apana.org.au, ebiggers@...nel.org, 
	Ard Biesheuvel <ardb@...nel.org>, Marc Zyngier <maz@...nel.org>, Will Deacon <will@...nel.org>, 
	Mark Rutland <mark.rutland@....com>, Kees Cook <keescook@...omium.org>, 
	Catalin Marinas <catalin.marinas@....com>, Mark Brown <broonie@...nel.org>
Subject: [PATCH 1/5] crypto/arm64: aes-ce-ccm - Avoid pointless yield of the
 NEON unit

From: Ard Biesheuvel <ardb@...nel.org>

Kernel mode NEON sections are now preemptible on arm64, and so there is
no need to yield it explicitly in order to prevent scheduling latency
spikes.

Signed-off-by: Ard Biesheuvel <ardb@...nel.org>
---
 arch/arm64/crypto/aes-ce-ccm-glue.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/arch/arm64/crypto/aes-ce-ccm-glue.c b/arch/arm64/crypto/aes-ce-ccm-glue.c
index 2d791d51891b..2eb4e76cabc3 100644
--- a/arch/arm64/crypto/aes-ce-ccm-glue.c
+++ b/arch/arm64/crypto/aes-ce-ccm-glue.c
@@ -114,11 +114,8 @@ static u32 ce_aes_ccm_auth_data(u8 mac[], u8 const in[], u32 abytes,
 			in += adv;
 			abytes -= adv;
 
-			if (unlikely(rem)) {
-				kernel_neon_end();
-				kernel_neon_begin();
+			if (unlikely(rem))
 				macp = 0;
-			}
 		} else {
 			u32 l = min(AES_BLOCK_SIZE - macp, abytes);
 
-- 
2.51.0.384.g4c02a37b29-goog