Start support for the RISC-V 64-bit architecture developed by UC Berkeley.

RISC-V is a new ISA designed to support computer research and education, and
is now become a standard open architecture for industry implementations.

This is a minimal set of changes required to run 'make kernel-toolchain'
using external (GNU) toolchain.

The FreeBSD/RISC-V project home: https://wiki.freebsd.org/riscv.

Reviewed by:	andrew, bdrewery, emaste, imp
Sponsored by:	DARPA, AFRL
Sponsored by:	HEIF5
Differential Revision:	https://reviews.freebsd.org/D4445

4 files changed, 241 insertions, 0 deletions

diff --git a/lib/csu/riscv/Makefile b/lib/csu/riscv/Makefile
new file mode 100644
index 0000000..9747619
--- /dev/null
+++ b/lib/csu/riscv/Makefile
@@ -0,0 +1,46 @@
+# $FreeBSD$
+
+.PATH: ${.CURDIR}/../common
+
+SRCS=		crt1.c crti.S crtn.S
+OBJS=		${SRCS:N*.h:R:S/$/.o/g}
+OBJS+=		Scrt1.o gcrt1.o
+CFLAGS+=	-I${.CURDIR}/../common \
+		-I${.CURDIR}/../../libc/include
+
+FILES=		${OBJS}
+FILESMODE=	${LIBMODE}
+FILESOWN=	${LIBOWN}
+FILESGRP=	${LIBGRP}
+FILESDIR=	${LIBDIR}
+# These FILES qualify as libraries for the purpose of LIBRARIES_ONLY.
+.undef LIBRARIES_ONLY
+
+CLEANFILES=	${OBJS}
+CLEANFILES+=	crt1.s gcrt1.s Scrt1.s
+
+# See the comment in lib/csu/common/crtbrand.c for the reason crt1.c is not
+# directly compiled to .o files.
+
+crt1.s: crt1.c
+	${CC} ${CFLAGS} -S -o ${.TARGET} ${.CURDIR}/crt1.c
+	sed ${SED_FIX_NOTE} ${.TARGET}
+
+crt1.o: crt1.s
+	${CC} ${ACFLAGS} -c -o ${.TARGET} crt1.s
+
+gcrt1.s: crt1.c
+	${CC} ${CFLAGS} -DGCRT -S -o ${.TARGET} ${.CURDIR}/crt1.c
+	sed ${SED_FIX_NOTE} ${.TARGET}
+
+gcrt1.o: gcrt1.s
+	${CC} ${ACFLAGS} -c -o ${.TARGET} gcrt1.s
+
+Scrt1.s: crt1.c
+	${CC} ${CFLAGS} -fPIC -DPIC -S -o ${.TARGET} ${.CURDIR}/crt1.c
+	sed ${SED_FIX_NOTE} ${.TARGET}
+
+Scrt1.o: Scrt1.s
+	${CC} ${ACFLAGS} -c -o ${.TARGET} Scrt1.s
+
+.include <bsd.lib.mk>
diff --git a/lib/csu/riscv/crt1.c b/lib/csu/riscv/crt1.c
new file mode 100644
index 0000000..0c3fbe6
--- /dev/null
+++ b/lib/csu/riscv/crt1.c
@@ -0,0 +1,89 @@
+/* LINTLIBRARY */
+/*-
+ * Copyright 1996-1998 John D. Polstra.
+ * Copyright (c) 2015 Ruslan Bukin <br@bsdpad.com>
+ * All rights reserved.
+ *
+ * Portions of this software were developed by SRI International and the
+ * University of Cambridge Computer Laboratory under DARPA/AFRL contract
+ * FA8750-10-C-0237 ("CTSRD"), as part of the DARPA CRASH research programme.
+ *
+ * Portions of this software were developed by the University of Cambridge
+ * Computer Laboratory as part of the CTSRD Project, with support from the
+ * UK Higher Education Innovation Fund (HEIF).
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <stdlib.h>
+
+#include "libc_private.h"
+#include "crtbrand.c"
+#include "ignore_init.c"
+
+typedef void (*fptr)(void);
+
+#ifdef GCRT
+extern void _mcleanup(void);
+extern void monstartup(void *, void *);
+extern int eprol;
+extern int etext;
+#endif
+
+void __start(int argc, char **argv, char **env, void (*cleanup)(void));
+
+/* The entry function. */
+__asm("	.text			\n"
+"	.align 0		\n"
+"	.globl _start		\n"
+"	_start:			\n"
+"	mv	a3, a2		\n" /* cleanup */
+"	addi	a1, a0, 8	\n" /* get argv */
+"	ld	a0, 0(a0)	\n" /* load argc */
+"	slli	t0, a0, 3	\n" /* mult by arg size */
+"	add	a2, a1, t0	\n" /* env is after argv */
+"	addi	a2, a2, 8	\n" /* argv is null terminated */
+"	lla	gp, _gp		\n" /* load global pointer */
+"	call	__start");
+
+void
+__start(int argc, char **argv, char **env, void (*cleanup)(void))
+{
+
+	handle_argv(argc, argv, env);
+
+	if (&_DYNAMIC != NULL)
+		atexit(cleanup);
+	else
+		_init_tls();
+
+#ifdef GCRT
+	atexit(_mcleanup);
+	monstartup(&eprol, &etext);
+__asm__("eprol:");
+#endif
+
+	handle_static_init(argc, argv, env);
+	exit(main(argc, argv, env));
+}
diff --git a/lib/csu/riscv/crti.S b/lib/csu/riscv/crti.S
new file mode 100644
index 0000000..df6027e
--- /dev/null
+++ b/lib/csu/riscv/crti.S
@@ -0,0 +1,58 @@
+/*-
+ * Copyright (c) 2015 Ruslan Bukin <br@bsdpad.com>
+ * All rights reserved.
+ *
+ * Portions of this software were developed by SRI International and the
+ * University of Cambridge Computer Laboratory under DARPA/AFRL contract
+ * FA8750-10-C-0237 ("CTSRD"), as part of the DARPA CRASH research programme.
+ *
+ * Portions of this software were developed by the University of Cambridge
+ * Computer Laboratory as part of the CTSRD Project, with support from the
+ * UK Higher Education Innovation Fund (HEIF).
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <machine/asm.h>
+__FBSDID("$FreeBSD$");
+
+# this puts _gp into .dynsym, so symlook_obj can now find that (see reloc.c)
+	.weak	_gp
+_gp:
+
+	.section .init,"ax",@progbits
+	.align	2
+	.globl	_init
+	.type	_init,@function
+_init:
+	addi	sp, sp, -16
+	sd	ra, 0(sp)
+
+	.section .fini,"ax",@progbits
+	.align	2
+	.globl	_fini
+	.type	_fini,@function
+_fini:
+	addi	sp, sp, -16
+	sd	ra, 0(sp)
+
+	.section .note.GNU-stack,"",%progbits
diff --git a/lib/csu/riscv/crtn.S b/lib/csu/riscv/crtn.S
new file mode 100644
index 0000000..b582471
--- /dev/null
+++ b/lib/csu/riscv/crtn.S
@@ -0,0 +1,48 @@
+/*-
+ * Copyright (c) 2015 Ruslan Bukin <br@bsdpad.com>
+ * All rights reserved.
+ *
+ * Portions of this software were developed by SRI International and the
+ * University of Cambridge Computer Laboratory under DARPA/AFRL contract
+ * FA8750-10-C-0237 ("CTSRD"), as part of the DARPA CRASH research programme.
+ *
+ * Portions of this software were developed by the University of Cambridge
+ * Computer Laboratory as part of the CTSRD Project, with support from the
+ * UK Higher Education Innovation Fund (HEIF).
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <machine/asm.h>
+__FBSDID("$FreeBSD$");
+
+	.section .init,"ax",@progbits
+	ld	ra, 0(sp)
+	addi	sp, sp, 16
+	ret
+
+	.section .fini,"ax",@progbits
+	ld	ra, 0(sp)
+	addi	sp, sp, 16
+	ret
+
+	.section .note.GNU-stack,"",%progbits