aarch64: Add optimized chacha20

It adds vectorized ChaCha20 implementation based on libgcrypt
cipher/chacha20-aarch64.S.  It is used as default and only
little-endian is supported (BE uses generic code).

As for generic implementation, the last step that XOR with the
input is omited.  The final state register clearing is also
omitted.

On a virtualized Linux on Apple M1 it shows the following
improvements (using formatted bench-arc4random data):

GENERIC                                    MB/s
-----------------------------------------------
arc4random [single-thread]               380.89
arc4random_buf(16) [single-thread]       500.73
arc4random_buf(32) [single-thread]       552.61
arc4random_buf(48) [single-thread]       566.82
arc4random_buf(64) [single-thread]       574.01
arc4random_buf(80) [single-thread]       581.02
arc4random_buf(96) [single-thread]       591.19
arc4random_buf(112) [single-thread]      592.29
arc4random_buf(128) [single-thread]      596.43
-----------------------------------------------

OPTIMIZED                                  MB/s
-----------------------------------------------
arc4random [single-thread]               569.60
arc4random_buf(16) [single-thread]       825.78
arc4random_buf(32) [single-thread]       987.03
arc4random_buf(48) [single-thread]      1042.39
arc4random_buf(64) [single-thread]      1075.50
arc4random_buf(80) [single-thread]      1094.68
arc4random_buf(96) [single-thread]      1130.16
arc4random_buf(112) [single-thread]     1129.58
arc4random_buf(128) [single-thread]     1137.91
-----------------------------------------------

Checked on aarch64-linux-gnu.

1 files changed, 314 insertions, 0 deletions

diff --git a/sysdeps/aarch64/chacha20-aarch64.S b/sysdeps/aarch64/chacha20-aarch64.S
new file mode 100644
index 0000000000..cce5291c5c
--- /dev/null
+++ b/sysdeps/aarch64/chacha20-aarch64.S
@@ -0,0 +1,314 @@
+/* Optimized AArch64 implementation of ChaCha20 cipher.
+   Copyright (C) 2022 Free Software Foundation, Inc.
+
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/* Copyright (C) 2017-2019 Jussi Kivilinna <jussi.kivilinna@iki.fi>
+
+   This file is part of Libgcrypt.
+
+   Libgcrypt is free software; you can redistribute it and/or modify
+   it under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation; either version 2.1 of
+   the License, or (at your option) any later version.
+
+   Libgcrypt is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with this program; if not, see <https://www.gnu.org/licenses/>.
+ */
+
+/* Based on D. J. Bernstein reference implementation at
+   http://cr.yp.to/chacha.html:
+
+   chacha-regs.c version 20080118
+   D. J. Bernstein
+   Public domain.  */
+
+#include <sysdep.h>
+
+/* Only LE is supported.  */
+#ifdef __AARCH64EL__
+
+#define GET_DATA_POINTER(reg, name) \
+        adrp    reg, name ; \
+        add     reg, reg, :lo12:name
+
+/* 'ret' instruction replacement for straight-line speculation mitigation */
+#define ret_spec_stop \
+        ret; dsb sy; isb;
+
+.cpu generic+simd
+
+.text
+
+/* register macros */
+#define INPUT     x0
+#define DST       x1
+#define SRC       x2
+#define NBLKS     x3
+#define ROUND     x4
+#define INPUT_CTR x5
+#define INPUT_POS x6
+#define CTR       x7
+
+/* vector registers */
+#define X0 v16
+#define X4 v17
+#define X8 v18
+#define X12 v19
+
+#define X1 v20
+#define X5 v21
+
+#define X9 v22
+#define X13 v23
+#define X2 v24
+#define X6 v25
+
+#define X3 v26
+#define X7 v27
+#define X11 v28
+#define X15 v29
+
+#define X10 v30
+#define X14 v31
+
+#define VCTR    v0
+#define VTMP0   v1
+#define VTMP1   v2
+#define VTMP2   v3
+#define VTMP3   v4
+#define X12_TMP v5
+#define X13_TMP v6
+#define ROT8    v7
+
+/**********************************************************************
+  helper macros
+ **********************************************************************/
+
+#define _(...) __VA_ARGS__
+
+#define vpunpckldq(s1, s2, dst) \
+	zip1 dst.4s, s2.4s, s1.4s;
+
+#define vpunpckhdq(s1, s2, dst) \
+	zip2 dst.4s, s2.4s, s1.4s;
+
+#define vpunpcklqdq(s1, s2, dst) \
+	zip1 dst.2d, s2.2d, s1.2d;
+
+#define vpunpckhqdq(s1, s2, dst) \
+	zip2 dst.2d, s2.2d, s1.2d;
+
+/* 4x4 32-bit integer matrix transpose */
+#define transpose_4x4(x0, x1, x2, x3, t1, t2, t3) \
+	vpunpckhdq(x1, x0, t2); \
+	vpunpckldq(x1, x0, x0); \
+	\
+	vpunpckldq(x3, x2, t1); \
+	vpunpckhdq(x3, x2, x2); \
+	\
+	vpunpckhqdq(t1, x0, x1); \
+	vpunpcklqdq(t1, x0, x0); \
+	\
+	vpunpckhqdq(x2, t2, x3); \
+	vpunpcklqdq(x2, t2, x2);
+
+/**********************************************************************
+  4-way chacha20
+ **********************************************************************/
+
+#define XOR(d,s1,s2) \
+	eor d.16b, s2.16b, s1.16b;
+
+#define PLUS(ds,s) \
+	add ds.4s, ds.4s, s.4s;
+
+#define ROTATE4(dst1,dst2,dst3,dst4,c,src1,src2,src3,src4) \
+	shl dst1.4s, src1.4s, #(c);		\
+	shl dst2.4s, src2.4s, #(c);		\
+	shl dst3.4s, src3.4s, #(c);		\
+	shl dst4.4s, src4.4s, #(c);		\
+	sri dst1.4s, src1.4s, #(32 - (c));	\
+	sri dst2.4s, src2.4s, #(32 - (c));	\
+	sri dst3.4s, src3.4s, #(32 - (c));	\
+	sri dst4.4s, src4.4s, #(32 - (c));
+
+#define ROTATE4_8(dst1,dst2,dst3,dst4,src1,src2,src3,src4) \
+	tbl dst1.16b, {src1.16b}, ROT8.16b;     \
+	tbl dst2.16b, {src2.16b}, ROT8.16b;	\
+	tbl dst3.16b, {src3.16b}, ROT8.16b;	\
+	tbl dst4.16b, {src4.16b}, ROT8.16b;
+
+#define ROTATE4_16(dst1,dst2,dst3,dst4,src1,src2,src3,src4) \
+	rev32 dst1.8h, src1.8h;			\
+	rev32 dst2.8h, src2.8h;			\
+	rev32 dst3.8h, src3.8h;			\
+	rev32 dst4.8h, src4.8h;
+
+#define QUARTERROUND4(a1,b1,c1,d1,a2,b2,c2,d2,a3,b3,c3,d3,a4,b4,c4,d4,ign,tmp1,tmp2,tmp3,tmp4) \
+	PLUS(a1,b1); PLUS(a2,b2);						\
+	PLUS(a3,b3); PLUS(a4,b4);						\
+	    XOR(tmp1,d1,a1); XOR(tmp2,d2,a2);					\
+	    XOR(tmp3,d3,a3); XOR(tmp4,d4,a4);					\
+		ROTATE4_16(d1, d2, d3, d4, tmp1, tmp2, tmp3, tmp4);		\
+	PLUS(c1,d1); PLUS(c2,d2);						\
+	PLUS(c3,d3); PLUS(c4,d4);						\
+	    XOR(tmp1,b1,c1); XOR(tmp2,b2,c2);					\
+	    XOR(tmp3,b3,c3); XOR(tmp4,b4,c4);					\
+		ROTATE4(b1, b2, b3, b4, 12, tmp1, tmp2, tmp3, tmp4)		\
+	PLUS(a1,b1); PLUS(a2,b2);						\
+	PLUS(a3,b3); PLUS(a4,b4);						\
+	    XOR(tmp1,d1,a1); XOR(tmp2,d2,a2);					\
+	    XOR(tmp3,d3,a3); XOR(tmp4,d4,a4);					\
+		ROTATE4_8(d1, d2, d3, d4, tmp1, tmp2, tmp3, tmp4)		\
+	PLUS(c1,d1); PLUS(c2,d2);						\
+	PLUS(c3,d3); PLUS(c4,d4);						\
+	    XOR(tmp1,b1,c1); XOR(tmp2,b2,c2);					\
+	    XOR(tmp3,b3,c3); XOR(tmp4,b4,c4);					\
+		ROTATE4(b1, b2, b3, b4, 7, tmp1, tmp2, tmp3, tmp4)		\
+
+.align 4
+L(__chacha20_blocks4_data_inc_counter):
+	.long 0,1,2,3
+
+.align 4
+L(__chacha20_blocks4_data_rot8):
+	.byte 3,0,1,2
+	.byte 7,4,5,6
+	.byte 11,8,9,10
+	.byte 15,12,13,14
+
+.hidden __chacha20_neon_blocks4
+ENTRY (__chacha20_neon_blocks4)
+	/* input:
+	 *	x0: input
+	 *	x1: dst
+	 *	x2: src
+	 *	x3: nblks (multiple of 4)
+	 */
+
+	GET_DATA_POINTER(CTR, L(__chacha20_blocks4_data_rot8))
+	add INPUT_CTR, INPUT, #(12*4);
+	ld1 {ROT8.16b}, [CTR];
+	GET_DATA_POINTER(CTR, L(__chacha20_blocks4_data_inc_counter))
+	mov INPUT_POS, INPUT;
+	ld1 {VCTR.16b}, [CTR];
+
+L(loop4):
+	/* Construct counter vectors X12 and X13 */
+
+	ld1 {X15.16b}, [INPUT_CTR];
+	mov ROUND, #20;
+	ld1 {VTMP1.16b-VTMP3.16b}, [INPUT_POS];
+
+	dup X12.4s, X15.s[0];
+	dup X13.4s, X15.s[1];
+	ldr CTR, [INPUT_CTR];
+	add X12.4s, X12.4s, VCTR.4s;
+	dup X0.4s, VTMP1.s[0];
+	dup X1.4s, VTMP1.s[1];
+	dup X2.4s, VTMP1.s[2];
+	dup X3.4s, VTMP1.s[3];
+	dup X14.4s, X15.s[2];
+	cmhi VTMP0.4s, VCTR.4s, X12.4s;
+	dup X15.4s, X15.s[3];
+	add CTR, CTR, #4; /* Update counter */
+	dup X4.4s, VTMP2.s[0];
+	dup X5.4s, VTMP2.s[1];
+	dup X6.4s, VTMP2.s[2];
+	dup X7.4s, VTMP2.s[3];
+	sub X13.4s, X13.4s, VTMP0.4s;
+	dup X8.4s, VTMP3.s[0];
+	dup X9.4s, VTMP3.s[1];
+	dup X10.4s, VTMP3.s[2];
+	dup X11.4s, VTMP3.s[3];
+	mov X12_TMP.16b, X12.16b;
+	mov X13_TMP.16b, X13.16b;
+	str CTR, [INPUT_CTR];
+
+L(round2):
+	subs ROUND, ROUND, #2
+	QUARTERROUND4(X0, X4,  X8, X12,   X1, X5,  X9, X13,
+		      X2, X6, X10, X14,   X3, X7, X11, X15,
+		      tmp:=,VTMP0,VTMP1,VTMP2,VTMP3)
+	QUARTERROUND4(X0, X5, X10, X15,   X1, X6, X11, X12,
+		      X2, X7,  X8, X13,   X3, X4,  X9, X14,
+		      tmp:=,VTMP0,VTMP1,VTMP2,VTMP3)
+	b.ne L(round2);
+
+	ld1 {VTMP0.16b, VTMP1.16b}, [INPUT_POS], #32;
+
+	PLUS(X12, X12_TMP);        /* INPUT + 12 * 4 + counter */
+	PLUS(X13, X13_TMP);        /* INPUT + 13 * 4 + counter */
+
+	dup VTMP2.4s, VTMP0.s[0]; /* INPUT + 0 * 4 */
+	dup VTMP3.4s, VTMP0.s[1]; /* INPUT + 1 * 4 */
+	dup X12_TMP.4s, VTMP0.s[2]; /* INPUT + 2 * 4 */
+	dup X13_TMP.4s, VTMP0.s[3]; /* INPUT + 3 * 4 */
+	PLUS(X0, VTMP2);
+	PLUS(X1, VTMP3);
+	PLUS(X2, X12_TMP);
+	PLUS(X3, X13_TMP);
+
+	dup VTMP2.4s, VTMP1.s[0]; /* INPUT + 4 * 4 */
+	dup VTMP3.4s, VTMP1.s[1]; /* INPUT + 5 * 4 */
+	dup X12_TMP.4s, VTMP1.s[2]; /* INPUT + 6 * 4 */
+	dup X13_TMP.4s, VTMP1.s[3]; /* INPUT + 7 * 4 */
+	ld1 {VTMP0.16b, VTMP1.16b}, [INPUT_POS];
+	mov INPUT_POS, INPUT;
+	PLUS(X4, VTMP2);
+	PLUS(X5, VTMP3);
+	PLUS(X6, X12_TMP);
+	PLUS(X7, X13_TMP);
+
+	dup VTMP2.4s, VTMP0.s[0]; /* INPUT + 8 * 4 */
+	dup VTMP3.4s, VTMP0.s[1]; /* INPUT + 9 * 4 */
+	dup X12_TMP.4s, VTMP0.s[2]; /* INPUT + 10 * 4 */
+	dup X13_TMP.4s, VTMP0.s[3]; /* INPUT + 11 * 4 */
+	dup VTMP0.4s, VTMP1.s[2]; /* INPUT + 14 * 4 */
+	dup VTMP1.4s, VTMP1.s[3]; /* INPUT + 15 * 4 */
+	PLUS(X8, VTMP2);
+	PLUS(X9, VTMP3);
+	PLUS(X10, X12_TMP);
+	PLUS(X11, X13_TMP);
+	PLUS(X14, VTMP0);
+	PLUS(X15, VTMP1);
+
+	transpose_4x4(X0, X1, X2, X3, VTMP0, VTMP1, VTMP2);
+	transpose_4x4(X4, X5, X6, X7, VTMP0, VTMP1, VTMP2);
+	transpose_4x4(X8, X9, X10, X11, VTMP0, VTMP1, VTMP2);
+	transpose_4x4(X12, X13, X14, X15, VTMP0, VTMP1, VTMP2);
+
+	subs NBLKS, NBLKS, #4;
+
+	st1 {X0.16b,X4.16B,X8.16b, X12.16b}, [DST], #64
+	st1 {X1.16b,X5.16b}, [DST], #32;
+	st1 {X9.16b, X13.16b, X2.16b, X6.16b}, [DST], #64
+	st1 {X10.16b,X14.16b}, [DST], #32;
+	st1 {X3.16b, X7.16b, X11.16b, X15.16b}, [DST], #64;
+
+	b.ne L(loop4);
+
+	ret_spec_stop
+END (__chacha20_neon_blocks4)
+
+#endif