[PATCH 1/5] lib/crc: arm64: Drop unnecessary chunking logic from crc64

[Eric Biggers]

On Tue, Mar 31, 2026 at 03:33:00PM -0700, Eric Biggers wrote:
> On Mon, Mar 30, 2026 at 04:46:32PM +0200, Ard Biesheuvel wrote:
> > On arm64, kernel mode NEON executes with preemption enabled, so there is
> > no need to chunk the input by hand.
> > 
> > Signed-off-by: Ard Biesheuvel <ardb at kernel.org>
> 
> There's still similar "chunking" in other arm64 code:
> 
>     $ git grep -E 'SZ_4K|cond_yield' lib/crypto/arm64
>     lib/crypto/arm64/chacha.h:              unsigned int todo = min_t(unsigned int, bytes, SZ_4K);
>     lib/crypto/arm64/poly1305.h:                    unsigned int todo = min_t(unsigned int, len, SZ_4K);
>     lib/crypto/arm64/sha1-ce-core.S:        cond_yield      1f, x5, x6
>     lib/crypto/arm64/sha256-ce.S:   cond_yield      1f, x5, x6
>     lib/crypto/arm64/sha3-ce-core.S:        cond_yield 4f, x8, x9
>     lib/crypto/arm64/sha512-ce-core.S:      cond_yield      3f, x4, x5
> 
> I thought it was still sticking around, despite kernel-mode NEON now
> being preemptible on arm64, because of CONFIG_PREEMPT_VOLUNTARY.
> 
> However, I see that support for CONFIG_PREEMPT_VOLUNTARY was recently
> removed on arm64.  So that's what finally makes this no longer needed,
> and we can now clean up these other cases too, right?
> 
> (Though, I can't find where the voluntary preemption points actually
> were.  So maybe they weren't actually there anyway.)

https://lore.kernel.org/linux-crypto/20260401000548.133151-1-ebiggers@kernel.org/
cleans up all the similar code in lib/crypto/arm64/.

- Eric