crypto: arm/chacha20 - refactor to allow varying number of rounds

In preparation for adding XChaCha12 support, rename/refactor the NEON
implementation of ChaCha20 to support different numbers of rounds.

Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 0 insertions, 556 deletions

diff --git a/arch/arm/crypto/chacha20-neon-core.S b/arch/arm/crypto/chacha20-neon-core.S
deleted file mode 100644
index 2335e5055d2b..000000000000
--- a/arch/arm/crypto/chacha20-neon-core.S
+++ /dev/null
@@ -1,556 +0,0 @@
-/*
- * ChaCha20 256-bit cipher algorithm, RFC7539, ARM NEON functions
- *
- * Copyright (C) 2016 Linaro, Ltd. <ard.biesheuvel@linaro.org>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * Based on:
- * ChaCha20 256-bit cipher algorithm, RFC7539, x64 SSE3 functions
- *
- * Copyright (C) 2015 Martin Willi
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- */
-
- /*
-  * NEON doesn't have a rotate instruction.  The alternatives are, more or less:
-  *
-  * (a)  vshl.u32 + vsri.u32		(needs temporary register)
-  * (b)  vshl.u32 + vshr.u32 + vorr	(needs temporary register)
-  * (c)  vrev32.16			(16-bit rotations only)
-  * (d)  vtbl.8 + vtbl.8		(multiple of 8 bits rotations only,
-  *					 needs index vector)
-  *
-  * ChaCha20 has 16, 12, 8, and 7-bit rotations.  For the 12 and 7-bit
-  * rotations, the only choices are (a) and (b).  We use (a) since it takes
-  * two-thirds the cycles of (b) on both Cortex-A7 and Cortex-A53.
-  *
-  * For the 16-bit rotation, we use vrev32.16 since it's consistently fastest
-  * and doesn't need a temporary register.
-  *
-  * For the 8-bit rotation, we use vtbl.8 + vtbl.8.  On Cortex-A7, this sequence
-  * is twice as fast as (a), even when doing (a) on multiple registers
-  * simultaneously to eliminate the stall between vshl and vsri.  Also, it
-  * parallelizes better when temporary registers are scarce.
-  *
-  * A disadvantage is that on Cortex-A53, the vtbl sequence is the same speed as
-  * (a), so the need to load the rotation table actually makes the vtbl method
-  * slightly slower overall on that CPU (~1.3% slower ChaCha20).  Still, it
-  * seems to be a good compromise to get a more significant speed boost on some
-  * CPUs, e.g. ~4.8% faster ChaCha20 on Cortex-A7.
-  */
-
-#include <linux/linkage.h>
-
-	.text
-	.fpu		neon
-	.align		5
-
-/*
- * chacha20_permute - permute one block
- *
- * Permute one 64-byte block where the state matrix is stored in the four NEON
- * registers q0-q3.  It performs matrix operations on four words in parallel,
- * but requires shuffling to rearrange the words after each round.
- *
- * Clobbers: r3, ip, q4-q5
- */
-chacha20_permute:
-
-	adr		ip, .Lrol8_table
-	mov		r3, #10
-	vld1.8		{d10}, [ip, :64]
-
-.Ldoubleround:
-	// x0 += x1, x3 = rotl32(x3 ^ x0, 16)
-	vadd.i32	q0, q0, q1
-	veor		q3, q3, q0
-	vrev32.16	q3, q3
-
-	// x2 += x3, x1 = rotl32(x1 ^ x2, 12)
-	vadd.i32	q2, q2, q3
-	veor		q4, q1, q2
-	vshl.u32	q1, q4, #12
-	vsri.u32	q1, q4, #20
-
-	// x0 += x1, x3 = rotl32(x3 ^ x0, 8)
-	vadd.i32	q0, q0, q1
-	veor		q3, q3, q0
-	vtbl.8		d6, {d6}, d10
-	vtbl.8		d7, {d7}, d10
-
-	// x2 += x3, x1 = rotl32(x1 ^ x2, 7)
-	vadd.i32	q2, q2, q3
-	veor		q4, q1, q2
-	vshl.u32	q1, q4, #7
-	vsri.u32	q1, q4, #25
-
-	// x1 = shuffle32(x1, MASK(0, 3, 2, 1))
-	vext.8		q1, q1, q1, #4
-	// x2 = shuffle32(x2, MASK(1, 0, 3, 2))
-	vext.8		q2, q2, q2, #8
-	// x3 = shuffle32(x3, MASK(2, 1, 0, 3))
-	vext.8		q3, q3, q3, #12
-
-	// x0 += x1, x3 = rotl32(x3 ^ x0, 16)
-	vadd.i32	q0, q0, q1
-	veor		q3, q3, q0
-	vrev32.16	q3, q3
-
-	// x2 += x3, x1 = rotl32(x1 ^ x2, 12)
-	vadd.i32	q2, q2, q3
-	veor		q4, q1, q2
-	vshl.u32	q1, q4, #12
-	vsri.u32	q1, q4, #20
-
-	// x0 += x1, x3 = rotl32(x3 ^ x0, 8)
-	vadd.i32	q0, q0, q1
-	veor		q3, q3, q0
-	vtbl.8		d6, {d6}, d10
-	vtbl.8		d7, {d7}, d10
-
-	// x2 += x3, x1 = rotl32(x1 ^ x2, 7)
-	vadd.i32	q2, q2, q3
-	veor		q4, q1, q2
-	vshl.u32	q1, q4, #7
-	vsri.u32	q1, q4, #25
-
-	// x1 = shuffle32(x1, MASK(2, 1, 0, 3))
-	vext.8		q1, q1, q1, #12
-	// x2 = shuffle32(x2, MASK(1, 0, 3, 2))
-	vext.8		q2, q2, q2, #8
-	// x3 = shuffle32(x3, MASK(0, 3, 2, 1))
-	vext.8		q3, q3, q3, #4
-
-	subs		r3, r3, #1
-	bne		.Ldoubleround
-
-	bx		lr
-ENDPROC(chacha20_permute)
-
-ENTRY(chacha20_block_xor_neon)
-	// r0: Input state matrix, s
-	// r1: 1 data block output, o
-	// r2: 1 data block input, i
-	push		{lr}
-
-	// x0..3 = s0..3
-	add		ip, r0, #0x20
-	vld1.32		{q0-q1}, [r0]
-	vld1.32		{q2-q3}, [ip]
-
-	vmov		q8, q0
-	vmov		q9, q1
-	vmov		q10, q2
-	vmov		q11, q3
-
-	bl		chacha20_permute
-
-	add		ip, r2, #0x20
-	vld1.8		{q4-q5}, [r2]
-	vld1.8		{q6-q7}, [ip]
-
-	// o0 = i0 ^ (x0 + s0)
-	vadd.i32	q0, q0, q8
-	veor		q0, q0, q4
-
-	// o1 = i1 ^ (x1 + s1)
-	vadd.i32	q1, q1, q9
-	veor		q1, q1, q5
-
-	// o2 = i2 ^ (x2 + s2)
-	vadd.i32	q2, q2, q10
-	veor		q2, q2, q6
-
-	// o3 = i3 ^ (x3 + s3)
-	vadd.i32	q3, q3, q11
-	veor		q3, q3, q7
-
-	add		ip, r1, #0x20
-	vst1.8		{q0-q1}, [r1]
-	vst1.8		{q2-q3}, [ip]
-
-	pop		{pc}
-ENDPROC(chacha20_block_xor_neon)
-
-ENTRY(hchacha20_block_neon)
-	// r0: Input state matrix, s
-	// r1: output (8 32-bit words)
-	push		{lr}
-
-	vld1.32		{q0-q1}, [r0]!
-	vld1.32		{q2-q3}, [r0]
-
-	bl		chacha20_permute
-
-	vst1.32		{q0}, [r1]!
-	vst1.32		{q3}, [r1]
-
-	pop		{pc}
-ENDPROC(hchacha20_block_neon)
-
-	.align		4
-.Lctrinc:	.word	0, 1, 2, 3
-.Lrol8_table:	.byte	3, 0, 1, 2, 7, 4, 5, 6
-
-	.align		5
-ENTRY(chacha20_4block_xor_neon)
-	push		{r4-r5}
-	mov		r4, sp			// preserve the stack pointer
-	sub		ip, sp, #0x20		// allocate a 32 byte buffer
-	bic		ip, ip, #0x1f		// aligned to 32 bytes
-	mov		sp, ip
-
-	// r0: Input state matrix, s
-	// r1: 4 data blocks output, o
-	// r2: 4 data blocks input, i
-
-	//
-	// This function encrypts four consecutive ChaCha20 blocks by loading
-	// the state matrix in NEON registers four times. The algorithm performs
-	// each operation on the corresponding word of each state matrix, hence
-	// requires no word shuffling. The words are re-interleaved before the
-	// final addition of the original state and the XORing step.
-	//
-
-	// x0..15[0-3] = s0..15[0-3]
-	add		ip, r0, #0x20
-	vld1.32		{q0-q1}, [r0]
-	vld1.32		{q2-q3}, [ip]
-
-	adr		r5, .Lctrinc
-	vdup.32		q15, d7[1]
-	vdup.32		q14, d7[0]
-	vld1.32		{q4}, [r5, :128]
-	vdup.32		q13, d6[1]
-	vdup.32		q12, d6[0]
-	vdup.32		q11, d5[1]
-	vdup.32		q10, d5[0]
-	vadd.u32	q12, q12, q4		// x12 += counter values 0-3
-	vdup.32		q9, d4[1]
-	vdup.32		q8, d4[0]
-	vdup.32		q7, d3[1]
-	vdup.32		q6, d3[0]
-	vdup.32		q5, d2[1]
-	vdup.32		q4, d2[0]
-	vdup.32		q3, d1[1]
-	vdup.32		q2, d1[0]
-	vdup.32		q1, d0[1]
-	vdup.32		q0, d0[0]
-
-	adr		ip, .Lrol8_table
-	mov		r3, #10
-	b		1f
-
-.Ldoubleround4:
-	vld1.32		{q8-q9}, [sp, :256]
-1:
-	// x0 += x4, x12 = rotl32(x12 ^ x0, 16)
-	// x1 += x5, x13 = rotl32(x13 ^ x1, 16)
-	// x2 += x6, x14 = rotl32(x14 ^ x2, 16)
-	// x3 += x7, x15 = rotl32(x15 ^ x3, 16)
-	vadd.i32	q0, q0, q4
-	vadd.i32	q1, q1, q5
-	vadd.i32	q2, q2, q6
-	vadd.i32	q3, q3, q7
-
-	veor		q12, q12, q0
-	veor		q13, q13, q1
-	veor		q14, q14, q2
-	veor		q15, q15, q3
-
-	vrev32.16	q12, q12
-	vrev32.16	q13, q13
-	vrev32.16	q14, q14
-	vrev32.16	q15, q15
-
-	// x8 += x12, x4 = rotl32(x4 ^ x8, 12)
-	// x9 += x13, x5 = rotl32(x5 ^ x9, 12)
-	// x10 += x14, x6 = rotl32(x6 ^ x10, 12)
-	// x11 += x15, x7 = rotl32(x7 ^ x11, 12)
-	vadd.i32	q8, q8, q12
-	vadd.i32	q9, q9, q13
-	vadd.i32	q10, q10, q14
-	vadd.i32	q11, q11, q15
-
-	vst1.32		{q8-q9}, [sp, :256]
-
-	veor		q8, q4, q8
-	veor		q9, q5, q9
-	vshl.u32	q4, q8, #12
-	vshl.u32	q5, q9, #12
-	vsri.u32	q4, q8, #20
-	vsri.u32	q5, q9, #20
-
-	veor		q8, q6, q10
-	veor		q9, q7, q11
-	vshl.u32	q6, q8, #12
-	vshl.u32	q7, q9, #12
-	vsri.u32	q6, q8, #20
-	vsri.u32	q7, q9, #20
-
-	// x0 += x4, x12 = rotl32(x12 ^ x0, 8)
-	// x1 += x5, x13 = rotl32(x13 ^ x1, 8)
-	// x2 += x6, x14 = rotl32(x14 ^ x2, 8)
-	// x3 += x7, x15 = rotl32(x15 ^ x3, 8)
-	vld1.8		{d16}, [ip, :64]
-	vadd.i32	q0, q0, q4
-	vadd.i32	q1, q1, q5
-	vadd.i32	q2, q2, q6
-	vadd.i32	q3, q3, q7
-
-	veor		q12, q12, q0
-	veor		q13, q13, q1
-	veor		q14, q14, q2
-	veor		q15, q15, q3
-
-	vtbl.8		d24, {d24}, d16
-	vtbl.8		d25, {d25}, d16
-	vtbl.8		d26, {d26}, d16
-	vtbl.8		d27, {d27}, d16
-	vtbl.8		d28, {d28}, d16
-	vtbl.8		d29, {d29}, d16
-	vtbl.8		d30, {d30}, d16
-	vtbl.8		d31, {d31}, d16
-
-	vld1.32		{q8-q9}, [sp, :256]
-
-	// x8 += x12, x4 = rotl32(x4 ^ x8, 7)
-	// x9 += x13, x5 = rotl32(x5 ^ x9, 7)
-	// x10 += x14, x6 = rotl32(x6 ^ x10, 7)
-	// x11 += x15, x7 = rotl32(x7 ^ x11, 7)
-	vadd.i32	q8, q8, q12
-	vadd.i32	q9, q9, q13
-	vadd.i32	q10, q10, q14
-	vadd.i32	q11, q11, q15
-
-	vst1.32		{q8-q9}, [sp, :256]
-
-	veor		q8, q4, q8
-	veor		q9, q5, q9
-	vshl.u32	q4, q8, #7
-	vshl.u32	q5, q9, #7
-	vsri.u32	q4, q8, #25
-	vsri.u32	q5, q9, #25
-
-	veor		q8, q6, q10
-	veor		q9, q7, q11
-	vshl.u32	q6, q8, #7
-	vshl.u32	q7, q9, #7
-	vsri.u32	q6, q8, #25
-	vsri.u32	q7, q9, #25
-
-	vld1.32		{q8-q9}, [sp, :256]
-
-	// x0 += x5, x15 = rotl32(x15 ^ x0, 16)
-	// x1 += x6, x12 = rotl32(x12 ^ x1, 16)
-	// x2 += x7, x13 = rotl32(x13 ^ x2, 16)
-	// x3 += x4, x14 = rotl32(x14 ^ x3, 16)
-	vadd.i32	q0, q0, q5
-	vadd.i32	q1, q1, q6
-	vadd.i32	q2, q2, q7
-	vadd.i32	q3, q3, q4
-
-	veor		q15, q15, q0
-	veor		q12, q12, q1
-	veor		q13, q13, q2
-	veor		q14, q14, q3
-
-	vrev32.16	q15, q15
-	vrev32.16	q12, q12
-	vrev32.16	q13, q13
-	vrev32.16	q14, q14
-
-	// x10 += x15, x5 = rotl32(x5 ^ x10, 12)
-	// x11 += x12, x6 = rotl32(x6 ^ x11, 12)
-	// x8 += x13, x7 = rotl32(x7 ^ x8, 12)
-	// x9 += x14, x4 = rotl32(x4 ^ x9, 12)
-	vadd.i32	q10, q10, q15
-	vadd.i32	q11, q11, q12
-	vadd.i32	q8, q8, q13
-	vadd.i32	q9, q9, q14
-
-	vst1.32		{q8-q9}, [sp, :256]
-
-	veor		q8, q7, q8
-	veor		q9, q4, q9
-	vshl.u32	q7, q8, #12
-	vshl.u32	q4, q9, #12
-	vsri.u32	q7, q8, #20
-	vsri.u32	q4, q9, #20
-
-	veor		q8, q5, q10
-	veor		q9, q6, q11
-	vshl.u32	q5, q8, #12
-	vshl.u32	q6, q9, #12
-	vsri.u32	q5, q8, #20
-	vsri.u32	q6, q9, #20
-
-	// x0 += x5, x15 = rotl32(x15 ^ x0, 8)
-	// x1 += x6, x12 = rotl32(x12 ^ x1, 8)
-	// x2 += x7, x13 = rotl32(x13 ^ x2, 8)
-	// x3 += x4, x14 = rotl32(x14 ^ x3, 8)
-	vld1.8		{d16}, [ip, :64]
-	vadd.i32	q0, q0, q5
-	vadd.i32	q1, q1, q6
-	vadd.i32	q2, q2, q7
-	vadd.i32	q3, q3, q4
-
-	veor		q15, q15, q0
-	veor		q12, q12, q1
-	veor		q13, q13, q2
-	veor		q14, q14, q3
-
-	vtbl.8		d30, {d30}, d16
-	vtbl.8		d31, {d31}, d16
-	vtbl.8		d24, {d24}, d16
-	vtbl.8		d25, {d25}, d16
-	vtbl.8		d26, {d26}, d16
-	vtbl.8		d27, {d27}, d16
-	vtbl.8		d28, {d28}, d16
-	vtbl.8		d29, {d29}, d16
-
-	vld1.32		{q8-q9}, [sp, :256]
-
-	// x10 += x15, x5 = rotl32(x5 ^ x10, 7)
-	// x11 += x12, x6 = rotl32(x6 ^ x11, 7)
-	// x8 += x13, x7 = rotl32(x7 ^ x8, 7)
-	// x9 += x14, x4 = rotl32(x4 ^ x9, 7)
-	vadd.i32	q10, q10, q15
-	vadd.i32	q11, q11, q12
-	vadd.i32	q8, q8, q13
-	vadd.i32	q9, q9, q14
-
-	vst1.32		{q8-q9}, [sp, :256]
-
-	veor		q8, q7, q8
-	veor		q9, q4, q9
-	vshl.u32	q7, q8, #7
-	vshl.u32	q4, q9, #7
-	vsri.u32	q7, q8, #25
-	vsri.u32	q4, q9, #25
-
-	veor		q8, q5, q10
-	veor		q9, q6, q11
-	vshl.u32	q5, q8, #7
-	vshl.u32	q6, q9, #7
-	vsri.u32	q5, q8, #25
-	vsri.u32	q6, q9, #25
-
-	subs		r3, r3, #1
-	bne		.Ldoubleround4
-
-	// x0..7[0-3] are in q0-q7, x10..15[0-3] are in q10-q15.
-	// x8..9[0-3] are on the stack.
-
-	// Re-interleave the words in the first two rows of each block (x0..7).
-	// Also add the counter values 0-3 to x12[0-3].
-	  vld1.32	{q8}, [r5, :128]	// load counter values 0-3
-	vzip.32		q0, q1			// => (0 1 0 1) (0 1 0 1)
-	vzip.32		q2, q3			// => (2 3 2 3) (2 3 2 3)
-	vzip.32		q4, q5			// => (4 5 4 5) (4 5 4 5)
-	vzip.32		q6, q7			// => (6 7 6 7) (6 7 6 7)
-	  vadd.u32	q12, q8			// x12 += counter values 0-3
-	vswp		d1, d4
-	vswp		d3, d6
-	  vld1.32	{q8-q9}, [r0]!		// load s0..7
-	vswp		d9, d12
-	vswp		d11, d14
-
-	// Swap q1 and q4 so that we'll free up consecutive registers (q0-q1)
-	// after XORing the first 32 bytes.
-	vswp		q1, q4
-
-	// First two rows of each block are (q0 q1) (q2 q6) (q4 q5) (q3 q7)
-
-	// x0..3[0-3] += s0..3[0-3]	(add orig state to 1st row of each block)
-	vadd.u32	q0, q0, q8
-	vadd.u32	q2, q2, q8
-	vadd.u32	q4, q4, q8
-	vadd.u32	q3, q3, q8
-
-	// x4..7[0-3] += s4..7[0-3]	(add orig state to 2nd row of each block)
-	vadd.u32	q1, q1, q9
-	vadd.u32	q6, q6, q9
-	vadd.u32	q5, q5, q9
-	vadd.u32	q7, q7, q9
-
-	// XOR first 32 bytes using keystream from first two rows of first block
-	vld1.8		{q8-q9}, [r2]!
-	veor		q8, q8, q0
-	veor		q9, q9, q1
-	vst1.8		{q8-q9}, [r1]!
-
-	// Re-interleave the words in the last two rows of each block (x8..15).
-	vld1.32		{q8-q9}, [sp, :256]
-	vzip.32		q12, q13	// => (12 13 12 13) (12 13 12 13)
-	vzip.32		q14, q15	// => (14 15 14 15) (14 15 14 15)
-	vzip.32		q8, q9		// => (8 9 8 9) (8 9 8 9)
-	vzip.32		q10, q11	// => (10 11 10 11) (10 11 10 11)
-	  vld1.32	{q0-q1}, [r0]	// load s8..15
-	vswp		d25, d28
-	vswp		d27, d30
-	vswp		d17, d20
-	vswp		d19, d22
-
-	// Last two rows of each block are (q8 q12) (q10 q14) (q9 q13) (q11 q15)
-
-	// x8..11[0-3] += s8..11[0-3]	(add orig state to 3rd row of each block)
-	vadd.u32	q8,  q8,  q0
-	vadd.u32	q10, q10, q0
-	vadd.u32	q9,  q9,  q0
-	vadd.u32	q11, q11, q0
-
-	// x12..15[0-3] += s12..15[0-3] (add orig state to 4th row of each block)
-	vadd.u32	q12, q12, q1
-	vadd.u32	q14, q14, q1
-	vadd.u32	q13, q13, q1
-	vadd.u32	q15, q15, q1
-
-	// XOR the rest of the data with the keystream
-
-	vld1.8		{q0-q1}, [r2]!
-	veor		q0, q0, q8
-	veor		q1, q1, q12
-	vst1.8		{q0-q1}, [r1]!
-
-	vld1.8		{q0-q1}, [r2]!
-	veor		q0, q0, q2
-	veor		q1, q1, q6
-	vst1.8		{q0-q1}, [r1]!
-
-	vld1.8		{q0-q1}, [r2]!
-	veor		q0, q0, q10
-	veor		q1, q1, q14
-	vst1.8		{q0-q1}, [r1]!
-
-	vld1.8		{q0-q1}, [r2]!
-	veor		q0, q0, q4
-	veor		q1, q1, q5
-	vst1.8		{q0-q1}, [r1]!
-
-	vld1.8		{q0-q1}, [r2]!
-	veor		q0, q0, q9
-	veor		q1, q1, q13
-	vst1.8		{q0-q1}, [r1]!
-
-	vld1.8		{q0-q1}, [r2]!
-	veor		q0, q0, q3
-	veor		q1, q1, q7
-	vst1.8		{q0-q1}, [r1]!
-
-	vld1.8		{q0-q1}, [r2]
-	  mov		sp, r4		// restore original stack pointer
-	veor		q0, q0, q11
-	veor		q1, q1, q15
-	vst1.8		{q0-q1}, [r1]
-
-	pop		{r4-r5}
-	bx		lr
-ENDPROC(chacha20_4block_xor_neon)