powerpc64: Add optimized chacha20

It adds vectorized ChaCha20 implementation based on libgcrypt
cipher/chacha20-ppc.c.  It targets POWER8 and it is used on default
for LE.

On a POWER8 it shows the following improvements (using formatted
bench-arc4random data):

POWER8

GENERIC                                    MB/s
-----------------------------------------------
arc4random [single-thread]               138.77
arc4random_buf(16) [single-thread]       174.36
arc4random_buf(32) [single-thread]       228.11
arc4random_buf(48) [single-thread]       252.31
arc4random_buf(64) [single-thread]       270.11
arc4random_buf(80) [single-thread]       278.97
arc4random_buf(96) [single-thread]       287.78
arc4random_buf(112) [single-thread]      291.92
arc4random_buf(128) [single-thread]      295.25

POWER8                                     MB/s
-----------------------------------------------
arc4random [single-thread]               198.06
arc4random_buf(16) [single-thread]       278.79
arc4random_buf(32) [single-thread]       448.89
arc4random_buf(48) [single-thread]       551.09
arc4random_buf(64) [single-thread]       646.12
arc4random_buf(80) [single-thread]       698.04
arc4random_buf(96) [single-thread]       756.06
arc4random_buf(112) [single-thread]      784.12
arc4random_buf(128) [single-thread]      808.04
-----------------------------------------------

Checked on powerpc64-linux-gnu and powerpc64le-linux-gnu.
Reviewed-by: Paul E. Murphy <murphyp@linux.ibm.com>

3 files changed, 47 insertions, 0 deletions

diff --git a/sysdeps/powerpc/powerpc64/be/multiarch/Makefile b/sysdeps/powerpc/powerpc64/be/multiarch/Makefile
new file mode 100644
index 0000000000..8c75165f7f
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/be/multiarch/Makefile
@@ -0,0 +1,4 @@
+ifeq ($(subdir),stdlib)
+sysdep_routines += chacha20-ppc
+CFLAGS-chacha20-ppc.c += -mcpu=power8
+endif
diff --git a/sysdeps/powerpc/powerpc64/be/multiarch/chacha20-ppc.c b/sysdeps/powerpc/powerpc64/be/multiarch/chacha20-ppc.c
new file mode 100644
index 0000000000..cf9e735326
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/be/multiarch/chacha20-ppc.c
@@ -0,0 +1 @@
+#include <sysdeps/powerpc/powerpc64/power8/chacha20-ppc.c>
diff --git a/sysdeps/powerpc/powerpc64/be/multiarch/chacha20_arch.h b/sysdeps/powerpc/powerpc64/be/multiarch/chacha20_arch.h
new file mode 100644
index 0000000000..08494dc045
--- /dev/null
+++ b/sysdeps/powerpc/powerpc64/be/multiarch/chacha20_arch.h
@@ -0,0 +1,42 @@
+/* PowerPC optimization for ChaCha20.
+   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 <stdbool.h>
+#include <ldsodefs.h>
+
+unsigned int __chacha20_power8_blocks4 (uint32_t *state, uint8_t *dst,
+					const uint8_t *src, size_t nblks)
+     attribute_hidden;
+
+static 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");
+
+  unsigned long int hwcap = GLRO(dl_hwcap);
+  unsigned long int hwcap2 = GLRO(dl_hwcap2);
+  if (hwcap2 & PPC_FEATURE2_ARCH_2_07 && hwcap & PPC_FEATURE_HAS_ALTIVEC)
+    __chacha20_power8_blocks4 (state, dst, src,
+			       CHACHA20_BUFSIZE / CHACHA20_BLOCK_SIZE);
+  else
+    chacha20_crypt_generic (state, dst, src, bytes);
+}