[v4] arm64: Move kernel mode FPSIMD buffer to the stack

[PATCH v4 01/21] crypto/arm64: aes-ce-ccm - Avoid pointless yield of the NEON unit

Posted by Ard Biesheuvel 1 month, 2 weeks ago

From: Ard Biesheuvel <ardb@kernel.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.

Reviewed-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.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);
 
-- 
2.51.1.930.gacf6e81ea2-goog

Re: [PATCH v4 01/21] crypto/arm64: aes-ce-ccm - Avoid pointless yield of the NEON unit

Posted by Herbert Xu 1 month, 1 week ago

On Fri, Oct 31, 2025 at 11:39:00AM +0100, Ard Biesheuvel wrote:
> From: Ard Biesheuvel <ardb@kernel.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.
> 
> Reviewed-by: Eric Biggers <ebiggers@kernel.org>
> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
> ---
>  arch/arm64/crypto/aes-ce-ccm-glue.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)

Acked-by: Herbert Xu <herbert@gondor.apana.org.au>

Thanks,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt