x86: Add SSE2 optimized chacha20

It adds vectorized ChaCha20 implementation based on libgcrypt
cipher/chacha20-amd64-ssse3.S.  It replaces the ROTATE_SHUF_2 (which
uses pshufb) by ROTATE2 and thus making the original implementation
SSE2.

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

On a Ryzen 9 5900X it shows the following improvements (using
formatted bench-arc4random data):

GENERIC                                    MB/s
-----------------------------------------------
arc4random [single-thread]               443.11
arc4random_buf(16) [single-thread]       552.27
arc4random_buf(32) [single-thread]       626.86
arc4random_buf(48) [single-thread]       649.81
arc4random_buf(64) [single-thread]       663.95
arc4random_buf(80) [single-thread]       674.78
arc4random_buf(96) [single-thread]       675.17
arc4random_buf(112) [single-thread]      680.69
arc4random_buf(128) [single-thread]      683.20
-----------------------------------------------

SSE                                        MB/s
-----------------------------------------------
arc4random [single-thread]               704.25
arc4random_buf(16) [single-thread]      1018.17
arc4random_buf(32) [single-thread]      1315.27
arc4random_buf(48) [single-thread]      1449.36
arc4random_buf(64) [single-thread]      1511.16
arc4random_buf(80) [single-thread]      1539.48
arc4random_buf(96) [single-thread]      1571.06
arc4random_buf(112) [single-thread]     1596.16
arc4random_buf(128) [single-thread]     1613.48
-----------------------------------------------

Checked on x86_64-linux-gnu.

3 files changed, 350 insertions, 0 deletions

diff --git a/sysdeps/x86_64/Makefile b/sysdeps/x86_64/Makefile
index c19bef2dec..3acd9755a5 100644
--- a/sysdeps/x86_64/Makefile
+++ b/sysdeps/x86_64/Makefile
@@ -5,6 +5,12 @@ ifeq ($(subdir),csu)
 gen-as-const-headers += link-defines.sym
 endif
 
+ifeq ($(subdir),stdlib)
+sysdep_routines += \
+  chacha20-amd64-sse2 \
+  # sysdep_routines
+endif
+
 ifeq ($(subdir),gmon)
 sysdep_routines += _mcount
 # We cannot compile _mcount.S with -pg because that would create
diff --git a/sysdeps/x86_64/chacha20-amd64-sse2.S b/sysdeps/x86_64/chacha20-amd64-sse2.S
new file mode 100644
index 0000000000..1178f06306
--- /dev/null
+++ b/sysdeps/x86_64/chacha20-amd64-sse2.S
@@ -0,0 +1,306 @@
+/* Optimized SSE2 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/>.  */
+
+/* chacha20-amd64-ssse3.S  -  SSSE3 implementation of ChaCha20 cipher
+
+   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>
+
+#ifdef PIC
+#  define rRIP (%rip)
+#else
+#  define rRIP
+#endif
+
+/* 'ret' instruction replacement for straight-line speculation mitigation */
+#define ret_spec_stop \
+        ret; int3;
+
+/* register macros */
+#define INPUT %rdi
+#define DST   %rsi
+#define SRC   %rdx
+#define NBLKS %rcx
+#define ROUND %eax
+
+/* stack structure */
+#define STACK_VEC_X12 (16)
+#define STACK_VEC_X13 (16 + STACK_VEC_X12)
+#define STACK_TMP     (16 + STACK_VEC_X13)
+#define STACK_TMP1    (16 + STACK_TMP)
+#define STACK_TMP2    (16 + STACK_TMP1)
+
+#define STACK_MAX     (16 + STACK_TMP2)
+
+/* vector registers */
+#define X0 %xmm0
+#define X1 %xmm1
+#define X2 %xmm2
+#define X3 %xmm3
+#define X4 %xmm4
+#define X5 %xmm5
+#define X6 %xmm6
+#define X7 %xmm7
+#define X8 %xmm8
+#define X9 %xmm9
+#define X10 %xmm10
+#define X11 %xmm11
+#define X12 %xmm12
+#define X13 %xmm13
+#define X14 %xmm14
+#define X15 %xmm15
+
+/**********************************************************************
+  helper macros
+ **********************************************************************/
+
+/* 4x4 32-bit integer matrix transpose */
+#define TRANSPOSE_4x4(x0, x1, x2, x3, t1, t2, t3) \
+	movdqa    x0, t2; \
+	punpckhdq x1, t2; \
+	punpckldq x1, x0; \
+	\
+	movdqa    x2, t1; \
+	punpckldq x3, t1; \
+	punpckhdq x3, x2; \
+	\
+	movdqa     x0, x1; \
+	punpckhqdq t1, x1; \
+	punpcklqdq t1, x0; \
+	\
+	movdqa     t2, x3; \
+	punpckhqdq x2, x3; \
+	punpcklqdq x2, t2; \
+	movdqa     t2, x2;
+
+/* fill xmm register with 32-bit value from memory */
+#define PBROADCASTD(mem32, xreg) \
+	movd mem32, xreg; \
+	pshufd $0, xreg, xreg;
+
+/**********************************************************************
+  4-way chacha20
+ **********************************************************************/
+
+#define ROTATE2(v1,v2,c,tmp1,tmp2)	\
+	movdqa v1, tmp1; 		\
+	movdqa v2, tmp2; 		\
+	psrld $(32 - (c)), v1;		\
+	pslld $(c), tmp1;		\
+	paddb tmp1, v1;			\
+	psrld $(32 - (c)), v2;		\
+	pslld $(c), tmp2;		\
+	paddb tmp2, v2;
+
+#define XOR(ds,s) \
+	pxor s, ds;
+
+#define PLUS(ds,s) \
+	paddd s, ds;
+
+#define QUARTERROUND2(a1,b1,c1,d1,a2,b2,c2,d2,ign,tmp1,tmp2)	\
+	PLUS(a1,b1); PLUS(a2,b2); XOR(d1,a1); XOR(d2,a2);	\
+	    ROTATE2(d1, d2, 16, tmp1, tmp2);			\
+	PLUS(c1,d1); PLUS(c2,d2); XOR(b1,c1); XOR(b2,c2);	\
+	    ROTATE2(b1, b2, 12, tmp1, tmp2);			\
+	PLUS(a1,b1); PLUS(a2,b2); XOR(d1,a1); XOR(d2,a2);	\
+	    ROTATE2(d1, d2, 8, tmp1, tmp2);			\
+	PLUS(c1,d1); PLUS(c2,d2); XOR(b1,c1); XOR(b2,c2);	\
+	    ROTATE2(b1, b2,  7, tmp1, tmp2);
+
+	.section .text.sse2,"ax",@progbits
+
+chacha20_data:
+	.align 16
+L(counter1):
+	.long 1,0,0,0
+L(inc_counter):
+	.long 0,1,2,3
+L(unsigned_cmp):
+	.long 0x80000000,0x80000000,0x80000000,0x80000000
+
+	.hidden __chacha20_sse2_blocks4
+ENTRY (__chacha20_sse2_blocks4)
+	/* input:
+	 *	%rdi: input
+	 *	%rsi: dst
+	 *	%rdx: src
+	 *	%rcx: nblks (multiple of 4)
+	 */
+
+	pushq %rbp;
+	cfi_adjust_cfa_offset(8);
+	cfi_rel_offset(rbp, 0)
+	movq %rsp, %rbp;
+	cfi_def_cfa_register(%rbp);
+
+	subq $STACK_MAX, %rsp;
+	andq $~15, %rsp;
+
+L(loop4):
+	mov $20, ROUND;
+
+	/* Construct counter vectors X12 and X13 */
+	movdqa L(inc_counter) rRIP, X0;
+	movdqa L(unsigned_cmp) rRIP, X2;
+	PBROADCASTD((12 * 4)(INPUT), X12);
+	PBROADCASTD((13 * 4)(INPUT), X13);
+	paddd X0, X12;
+	movdqa X12, X1;
+	pxor X2, X0;
+	pxor X2, X1;
+	pcmpgtd X1, X0;
+	psubd X0, X13;
+	movdqa X12, (STACK_VEC_X12)(%rsp);
+	movdqa X13, (STACK_VEC_X13)(%rsp);
+
+	/* Load vectors */
+	PBROADCASTD((0 * 4)(INPUT), X0);
+	PBROADCASTD((1 * 4)(INPUT), X1);
+	PBROADCASTD((2 * 4)(INPUT), X2);
+	PBROADCASTD((3 * 4)(INPUT), X3);
+	PBROADCASTD((4 * 4)(INPUT), X4);
+	PBROADCASTD((5 * 4)(INPUT), X5);
+	PBROADCASTD((6 * 4)(INPUT), X6);
+	PBROADCASTD((7 * 4)(INPUT), X7);
+	PBROADCASTD((8 * 4)(INPUT), X8);
+	PBROADCASTD((9 * 4)(INPUT), X9);
+	PBROADCASTD((10 * 4)(INPUT), X10);
+	PBROADCASTD((11 * 4)(INPUT), X11);
+	PBROADCASTD((14 * 4)(INPUT), X14);
+	PBROADCASTD((15 * 4)(INPUT), X15);
+	movdqa X11, (STACK_TMP)(%rsp);
+	movdqa X15, (STACK_TMP1)(%rsp);
+
+L(round2_4):
+	QUARTERROUND2(X0, X4,  X8, X12,   X1, X5,  X9, X13, tmp:=,X11,X15)
+	movdqa (STACK_TMP)(%rsp), X11;
+	movdqa (STACK_TMP1)(%rsp), X15;
+	movdqa X8, (STACK_TMP)(%rsp);
+	movdqa X9, (STACK_TMP1)(%rsp);
+	QUARTERROUND2(X2, X6, X10, X14,   X3, X7, X11, X15, tmp:=,X8,X9)
+	QUARTERROUND2(X0, X5, X10, X15,   X1, X6, X11, X12, tmp:=,X8,X9)
+	movdqa (STACK_TMP)(%rsp), X8;
+	movdqa (STACK_TMP1)(%rsp), X9;
+	movdqa X11, (STACK_TMP)(%rsp);
+	movdqa X15, (STACK_TMP1)(%rsp);
+	QUARTERROUND2(X2, X7,  X8, X13,   X3, X4,  X9, X14, tmp:=,X11,X15)
+	sub $2, ROUND;
+	jnz L(round2_4);
+
+	/* tmp := X15 */
+	movdqa (STACK_TMP)(%rsp), X11;
+	PBROADCASTD((0 * 4)(INPUT), X15);
+	PLUS(X0, X15);
+	PBROADCASTD((1 * 4)(INPUT), X15);
+	PLUS(X1, X15);
+	PBROADCASTD((2 * 4)(INPUT), X15);
+	PLUS(X2, X15);
+	PBROADCASTD((3 * 4)(INPUT), X15);
+	PLUS(X3, X15);
+	PBROADCASTD((4 * 4)(INPUT), X15);
+	PLUS(X4, X15);
+	PBROADCASTD((5 * 4)(INPUT), X15);
+	PLUS(X5, X15);
+	PBROADCASTD((6 * 4)(INPUT), X15);
+	PLUS(X6, X15);
+	PBROADCASTD((7 * 4)(INPUT), X15);
+	PLUS(X7, X15);
+	PBROADCASTD((8 * 4)(INPUT), X15);
+	PLUS(X8, X15);
+	PBROADCASTD((9 * 4)(INPUT), X15);
+	PLUS(X9, X15);
+	PBROADCASTD((10 * 4)(INPUT), X15);
+	PLUS(X10, X15);
+	PBROADCASTD((11 * 4)(INPUT), X15);
+	PLUS(X11, X15);
+	movdqa (STACK_VEC_X12)(%rsp), X15;
+	PLUS(X12, X15);
+	movdqa (STACK_VEC_X13)(%rsp), X15;
+	PLUS(X13, X15);
+	movdqa X13, (STACK_TMP)(%rsp);
+	PBROADCASTD((14 * 4)(INPUT), X15);
+	PLUS(X14, X15);
+	movdqa (STACK_TMP1)(%rsp), X15;
+	movdqa X14, (STACK_TMP1)(%rsp);
+	PBROADCASTD((15 * 4)(INPUT), X13);
+	PLUS(X15, X13);
+	movdqa X15, (STACK_TMP2)(%rsp);
+
+	/* Update counter */
+	addq $4, (12 * 4)(INPUT);
+
+	TRANSPOSE_4x4(X0, X1, X2, X3, X13, X14, X15);
+	movdqu X0, (64 * 0 + 16 * 0)(DST)
+	movdqu X1, (64 * 1 + 16 * 0)(DST)
+	movdqu X2, (64 * 2 + 16 * 0)(DST)
+	movdqu X3, (64 * 3 + 16 * 0)(DST)
+	TRANSPOSE_4x4(X4, X5, X6, X7, X0, X1, X2);
+	movdqa (STACK_TMP)(%rsp), X13;
+	movdqa (STACK_TMP1)(%rsp), X14;
+	movdqa (STACK_TMP2)(%rsp), X15;
+	movdqu X4, (64 * 0 + 16 * 1)(DST)
+	movdqu X5, (64 * 1 + 16 * 1)(DST)
+	movdqu X6, (64 * 2 + 16 * 1)(DST)
+	movdqu X7, (64 * 3 + 16 * 1)(DST)
+	TRANSPOSE_4x4(X8, X9, X10, X11, X0, X1, X2);
+	movdqu X8,  (64 * 0 + 16 * 2)(DST)
+	movdqu X9,  (64 * 1 + 16 * 2)(DST)
+	movdqu X10, (64 * 2 + 16 * 2)(DST)
+	movdqu X11, (64 * 3 + 16 * 2)(DST)
+	TRANSPOSE_4x4(X12, X13, X14, X15, X0, X1, X2);
+	movdqu X12, (64 * 0 + 16 * 3)(DST)
+	movdqu X13, (64 * 1 + 16 * 3)(DST)
+	movdqu X14, (64 * 2 + 16 * 3)(DST)
+	movdqu X15, (64 * 3 + 16 * 3)(DST)
+
+	sub $4, NBLKS;
+	lea (4 * 64)(DST), DST;
+	lea (4 * 64)(SRC), SRC;
+	jnz L(loop4);
+
+	/* eax zeroed by round loop. */
+	leave;
+	cfi_adjust_cfa_offset(-8)
+	cfi_def_cfa_register(%rsp);
+	ret_spec_stop;
+END (__chacha20_sse2_blocks4)
diff --git a/sysdeps/x86_64/chacha20_arch.h b/sysdeps/x86_64/chacha20_arch.h
new file mode 100644
index 0000000000..60dee08045
--- /dev/null
+++ b/sysdeps/x86_64/chacha20_arch.h
@@ -0,0 +1,38 @@
+/* Chacha20 implementation, used on arc4random.
+   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/>.  */
+
+#include <ldsodefs.h>
+#include <cpu-features.h>
+#include <sys/param.h>
+
+unsigned int __chacha20_sse2_blocks4 (uint32_t *state, uint8_t *dst,
+				      const uint8_t *src, size_t nblks)
+     attribute_hidden;
+
+static inline void
+chacha20_crypt (uint32_t *state, uint8_t *dst, const uint8_t *src,
+		size_t bytes)
+{
+  _Static_assert (CHACHA20_BUFSIZE % 4 == 0,
+		  "CHACHA20_BUFSIZE not multiple of 4");
+  _Static_assert (CHACHA20_BUFSIZE >= CHACHA20_BLOCK_SIZE * 4,
+		  "CHACHA20_BUFSIZE <= CHACHA20_BLOCK_SIZE * 4");
+
+  __chacha20_sse2_blocks4 (state, dst, src,
+			   CHACHA20_BUFSIZE / CHACHA20_BLOCK_SIZE);
+}