On 25 July 2018 at 03:29, Eric Biggers <ebiggers3@xxxxxxxxx> wrote: > From: Eric Biggers <ebiggers@xxxxxxxxxx> > > The 4-way ChaCha20 NEON code implements 16-bit rotates with vrev32.16, > but the one-way code (used on remainder blocks) implements it with > vshl + vsri, which is slower. Switch the one-way code to vrev32.16 too. > > Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx> Acked-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> > --- > arch/arm/crypto/chacha20-neon-core.S | 10 ++++------ > 1 file changed, 4 insertions(+), 6 deletions(-) > > diff --git a/arch/arm/crypto/chacha20-neon-core.S b/arch/arm/crypto/chacha20-neon-core.S > index 3fecb2124c35..451a849ad518 100644 > --- a/arch/arm/crypto/chacha20-neon-core.S > +++ b/arch/arm/crypto/chacha20-neon-core.S > @@ -51,9 +51,8 @@ ENTRY(chacha20_block_xor_neon) > .Ldoubleround: > // x0 += x1, x3 = rotl32(x3 ^ x0, 16) > vadd.i32 q0, q0, q1 > - veor q4, q3, q0 > - vshl.u32 q3, q4, #16 > - vsri.u32 q3, q4, #16 > + veor q3, q3, q0 > + vrev32.16 q3, q3 > > // x2 += x3, x1 = rotl32(x1 ^ x2, 12) > vadd.i32 q2, q2, q3 > @@ -82,9 +81,8 @@ ENTRY(chacha20_block_xor_neon) > > // x0 += x1, x3 = rotl32(x3 ^ x0, 16) > vadd.i32 q0, q0, q1 > - veor q4, q3, q0 > - vshl.u32 q3, q4, #16 > - vsri.u32 q3, q4, #16 > + veor q3, q3, q0 > + vrev32.16 q3, q3 > > // x2 += x3, x1 = rotl32(x1 ^ x2, 12) > vadd.i32 q2, q2, q3 > -- > 2.18.0 >
