Re: [PATCH RT] arm*: disable NEON in kernel mode

From: Sebastian Andrzej Siewior
Date: Mon Dec 04 2017 - 04:22:10 EST


On 2017-12-01 18:24:10 [+0000], Dave Martin wrote:
> > diff --git a/arch/arm64/crypto/Kconfig b/arch/arm64/crypto/Kconfig
> > index 70c517aa4501..2a5f05b5a19a 100644
> > --- a/arch/arm64/crypto/Kconfig
> > +++ b/arch/arm64/crypto/Kconfig
> > @@ -19,19 +19,19 @@ config CRYPTO_SHA512_ARM64
> >
> > config CRYPTO_SHA1_ARM64_CE
> > tristate "SHA-1 digest algorithm (ARMv8 Crypto Extensions)"
> > - depends on KERNEL_MODE_NEON
> > + depends on KERNEL_MODE_NEON && !PREEMPT_RT_BASE
> > select CRYPTO_HASH
> > select CRYPTO_SHA1
>
> Sebastian, can you piont to where sha1 (say) hits this issue?
> I wonder whether this is really a sign that some refactoring is needed.

I disabled all NEON in one go. Looking at this, it shouldn't be a issue
with the block-walk. The only thing that might be a problem is that it
can do multiple blocks in one go.

> Cheers
> ---Dave

Sebastian