8283929: GHA: Add RISC-V build config

8313701: GHA: RISC-V should use the official repository for bootstrap
8285630: Fix a configure error in RISC-V cross build

Reviewed-by: fyang, luhenry
Backport-of: 85d4b49151e9529051f1ed344749a487d3e92165

.github/workflows/build-cross-compile.yml

@@ -54,6 +54,7 @@ jobs:
           - arm
           - s390x
           - ppc64le
+          - riscv64
         include:
           - target-cpu: aarch64
             gnu-arch: aarch64
@@ -76,6 +77,11 @@ jobs:
             debian-arch: ppc64el
             debian-repository: https://httpredir.debian.org/debian/
             debian-version: bullseye
+          - target-cpu: riscv64
+            gnu-arch: riscv64
+            debian-arch: riscv64
+            debian-repository: https://httpredir.debian.org/debian/
+            debian-version: sid
 
     steps:
       - name: 'Checkout the JDK source'

make/autoconf/build-aux/config.sub

@@ -1,6 +1,6 @@
 #!/bin/sh
 #
-# Copyright (c) 2014, 2020, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2014, 2022, Oracle and/or its affiliates. All rights reserved.
 # DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 #
 # This code is free software; you can redistribute it and/or modify it
@@ -40,6 +40,13 @@ if echo $* | grep pc-msys >/dev/null ; then
     exit
 fi
 
+# Canonicalize for riscv which autoconf-config.sub doesn't handle
+if echo $* | grep '^riscv\(32\|64\)-linux' >/dev/null ; then
+    result=`echo $@ | sed 's/linux/unknown-linux/'`
+    echo $result
+    exit
+fi
+
 # First, filter out everything that doesn't begin with "aarch64-"
 if ! echo $* | grep '^aarch64-' >/dev/null ; then
     . $DIR/autoconf-config.sub "$@"