Add RISC-V 32 cpuid support

Mainly from #17640

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/18308)

crypto/build.info

@@ -52,6 +52,7 @@ IF[{- !$disabled{asm} && $config{processor} ne '386' -}]
   $CPUIDASM_c64xplus=c64xpluscpuid.s
 
   $CPUIDASM_riscv64=riscvcap.c riscv64cpuid.s
+  $CPUIDASM_riscv32=riscvcap.c riscv32cpuid.s
 
   # Now that we have defined all the arch specific variables, use the
   # appropriate one, and define the appropriate macros
@@ -136,6 +137,7 @@ INCLUDE[armv4cpuid.o]=.
 GENERATE[s390xcpuid.S]=s390xcpuid.pl
 INCLUDE[s390xcpuid.o]=.
 GENERATE[riscv64cpuid.s]=riscv64cpuid.pl
+GENERATE[riscv32cpuid.s]=riscv32cpuid.pl
 
 IF[{- $config{target} =~ /^(?:Cygwin|mingw|VC-|BC-)/ -}]
   SHARED_SOURCE[../libcrypto]=dllmain.c

crypto/riscv32cpuid.pl

@@ -0,0 +1,88 @@
+#! /usr/bin/env perl
+# Copyright 2022 The OpenSSL Project Authors. All Rights Reserved.
+#
+# Licensed under the Apache License 2.0 (the "License").  You may not use
+# this file except in compliance with the License.  You can obtain a copy
+# in the file LICENSE in the source distribution or at
+# https://www.openssl.org/source/license.html
+
+
+# $output is the last argument if it looks like a file (it has an extension)
+# $flavour is the first argument if it doesn't look like a file
+$output = $#ARGV >= 0 && $ARGV[$#ARGV] =~ m|\.\w+$| ? pop : undef;
+$flavour = $#ARGV >= 0 && $ARGV[0] !~ m|\.| ? shift : undef;
+
+$output and open STDOUT,">$output";
+
+{
+my ($in_a,$in_b,$len,$x,$temp1,$temp2) = ('a0','a1','a2','t0','t1','t2');
+$code.=<<___;
+################################################################################
+# int CRYPTO_memcmp(const void * in_a, const void * in_b, size_t len)
+################################################################################
+.text
+.balign 16
+.globl CRYPTO_memcmp
+.type   CRYPTO_memcmp,\@function
+CRYPTO_memcmp:
+    li      $x,0
+    beqz    $len,2f   # len == 0
+1:
+    lbu     $temp1,0($in_a)
+    lbu     $temp2,0($in_b)
+    addi    $in_a,$in_a,1
+    addi    $in_b,$in_b,1
+    addi    $len,$len,-1
+    xor     $temp1,$temp1,$temp2
+    or      $x,$x,$temp1
+    bgtz    $len,1b
+2:
+    mv      a0,$x
+    ret
+___
+}
+{
+my ($ptr,$len,$temp1,$temp2) = ('a0','a1','t0','t1');
+$code.=<<___;
+################################################################################
+# void OPENSSL_cleanse(void *ptr, size_t len)
+################################################################################
+.text
+.balign 16
+.globl OPENSSL_cleanse
+.type   OPENSSL_cleanse,\@function
+OPENSSL_cleanse:
+    beqz    $len,2f         # len == 0, return
+    srli    $temp1,$len,4
+    bnez    $temp1,3f       # len > 15
+
+1:  # Store <= 15 individual bytes
+    sb      x0,0($ptr)
+    addi    $ptr,$ptr,1
+    addi    $len,$len,-1
+    bnez    $len,1b
+2:
+    ret
+
+3:  # Store individual bytes until we are aligned
+    andi    $temp1,$ptr,0x3
+    beqz    $temp1,4f
+    sb      x0,0($ptr)
+    addi    $ptr,$ptr,1
+    addi    $len,$len,-1
+    j       3b
+
+4:  # Store aligned words
+    li      $temp2,4
+4:
+    sw      x0,0($ptr)
+    addi    $ptr,$ptr,4
+    addi    $len,$len,-4
+    bge     $len,$temp2,4b  # if len>=4 loop
+    bnez    $len,1b         # if len<4 and len != 0, store remaining bytes
+    ret
+___
+}
+
+print $code;
+close STDOUT or die "error closing STDOUT: $!";