unix: add support for openbsd/riscv64

Updates golang/go#55999

Change-Id: I2ea76f72faaddc46da0c37650de702bc7e90eea2
Reviewed-on: https://go-review.googlesource.com/c/sys/+/439976
TryBot-Result: Gopher Robot <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>
Reviewed-by: Bryan Mills <[email protected]>
Run-TryBot: Joel Sing <[email protected]>
Reviewed-by: Tobias Klauser <[email protected]>

Author: 4a6f656c

unix/mkall.sh

@@ -182,6 +182,15 @@ openbsd_mips64)
 	# API consistent across platforms.
 	mktypes="GOARCH=$GOARCH go tool cgo -godefs -- -fsigned-char"
 	;;
+openbsd_riscv64)
+	mkasm="go run mkasm.go"
+	mkerrors="$mkerrors -m64"
+	mksyscall="go run mksyscall.go -openbsd -libc"
+	mksysctl="go run mksysctl_openbsd.go"
+	# Let the type of C char be signed for making the bare syscall
+	# API consistent across platforms.
+	mktypes="GOARCH=$GOARCH go tool cgo -godefs -- -fsigned-char"
+	;;
 solaris_amd64)
 	mksyscall="go run mksyscall_solaris.go"
 	mkerrors="$mkerrors -m64"

unix/mkasm.go

@@ -23,7 +23,7 @@ func archPtrSize(arch string) int {
 	switch arch {
 	case "386", "arm":
 		return 4
-	case "amd64", "arm64", "mips64":
+	case "amd64", "arm64", "mips64", "riscv64":
 		return 8
 	default:
 		log.Fatalf("Unknown arch %q", arch)

unix/syscall_openbsd_riscv64.go

@@ -0,0 +1,42 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build riscv64 && openbsd
+// +build riscv64,openbsd
+
+package unix
+
+func setTimespec(sec, nsec int64) Timespec {
+	return Timespec{Sec: sec, Nsec: nsec}
+}
+
+func setTimeval(sec, usec int64) Timeval {
+	return Timeval{Sec: sec, Usec: usec}
+}
+
+func SetKevent(k *Kevent_t, fd, mode, flags int) {
+	k.Ident = uint64(fd)
+	k.Filter = int16(mode)
+	k.Flags = uint16(flags)
+}
+
+func (iov *Iovec) SetLen(length int) {
+	iov.Len = uint64(length)
+}
+
+func (msghdr *Msghdr) SetControllen(length int) {
+	msghdr.Controllen = uint32(length)
+}
+
+func (msghdr *Msghdr) SetIovlen(length int) {
+	msghdr.Iovlen = uint32(length)
+}
+
+func (cmsg *Cmsghdr) SetLen(length int) {
+	cmsg.Len = uint32(length)
+}
+
+// SYS___SYSCTL is used by syscall_bsd.go for all BSDs, but in modern versions
+// of openbsd/riscv64 the syscall is called sysctl instead of __sysctl.
+const SYS___SYSCTL = SYS_SYSCTL