Bring in initial libc and libstand support for RISC-V.

Reviewed by:	andrew, emaste, kib
Sponsored by:	DARPA, AFRL
Sponsored by:	HEIF5
Differential Revision:	https://reviews.freebsd.org/D4943

9 files changed, 459 insertions, 0 deletions

diff --git a/lib/libc/riscv/sys/Makefile.inc b/lib/libc/riscv/sys/Makefile.inc
new file mode 100644
index 0000000..cb56f73
--- /dev/null
+++ b/lib/libc/riscv/sys/Makefile.inc
@@ -0,0 +1,25 @@
+# $FreeBSD$
+
+SRCS+=	trivial-vdso_tc.c
+
+#MDASM= ptrace.S
+MDASM=	brk.S \
+	cerror.S \
+	pipe.S \
+	sbrk.S \
+	shmat.S \
+	sigreturn.S \
+	syscall.S \
+	vfork.S
+
+# Don't generate default code for these syscalls:
+NOASM=	break.o \
+	exit.o \
+	getlogin.o \
+	openbsd_poll.o \
+	sstk.o \
+	vfork.o \
+	yield.o
+
+PSEUDO= _exit.o \
+	_getlogin.o
diff --git a/lib/libc/riscv/sys/brk.S b/lib/libc/riscv/sys/brk.S
new file mode 100644
index 0000000..4ecd923
--- /dev/null
+++ b/lib/libc/riscv/sys/brk.S
@@ -0,0 +1,79 @@
+/*-
+ * 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("$FreeBSD$");
+
+#include "SYS.h"
+
+	.globl	_C_LABEL(_end)
+
+	.data
+	.align	3
+	.globl	_C_LABEL(minbrk)
+	.type	_C_LABEL(minbrk), %object
+_C_LABEL(minbrk):
+	.quad	_C_LABEL(_end)
+
+	.text
+/*
+ * int brk(const void *addr);
+ */
+ENTRY(_brk)
+	WEAK_REFERENCE(_brk, brk)
+
+	/* Load the address of minbrk */
+	la	a3, minbrk
+	ld	a2, 0(a3)
+
+	/* Validate the address */
+	bge	a0, a2, 1f
+	/* Invalid, set it to the minimum */
+	mv	a0, a2
+
+	/* Backup the new address */
+1:	mv	a4, a0
+
+	/* Update for this value, will overwrite a0 and a1 */
+	_SYSCALL(break)
+	bnez	t0, cerror
+
+	/* Store the new curbrk value */
+	la	a2, curbrk
+	sd	a4, 0(a2)
+
+	/* Return success */
+	li	a0, 0
+	ret
+END(_brk)
diff --git a/lib/libc/riscv/sys/cerror.S b/lib/libc/riscv/sys/cerror.S
new file mode 100644
index 0000000..117080e
--- /dev/null
+++ b/lib/libc/riscv/sys/cerror.S
@@ -0,0 +1,50 @@
+/*-
+ * 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("$FreeBSD$");
+
+ENTRY(cerror)
+	addi	sp, sp, -16
+	sd	a0, 0(sp)
+	sd	ra, 8(sp)
+	call	_C_LABEL(__error)
+	ld	a1, 0(sp)
+	ld	ra, 8(sp)
+	sw	a1, 0(a0)
+	li	a0, -1
+	li	a1, -1
+	addi	sp, sp, 16
+	ret
+END(cerror)
diff --git a/lib/libc/riscv/sys/pipe.S b/lib/libc/riscv/sys/pipe.S
new file mode 100644
index 0000000..b265a6a
--- /dev/null
+++ b/lib/libc/riscv/sys/pipe.S
@@ -0,0 +1,57 @@
+/*-
+ * 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("$FreeBSD$");
+
+#include "SYS.h"
+
+ENTRY(__sys_pipe)
+	WEAK_REFERENCE(__sys_pipe, pipe)
+
+	/* Backup the pointer passed to us */
+	mv	a2, a0
+
+	/* Make the syscall */
+	_SYSCALL(pipe)
+	bnez	t0, cerror
+
+	/* Store the result */
+	sw	a0, 0(a2)
+	sw	a1, 4(a2)
+
+	/* Return */
+	li	a0, 0
+	ret
+END(__sys_pipe)
diff --git a/lib/libc/riscv/sys/sbrk.S b/lib/libc/riscv/sys/sbrk.S
new file mode 100644
index 0000000..1860a98
--- /dev/null
+++ b/lib/libc/riscv/sys/sbrk.S
@@ -0,0 +1,77 @@
+/*-
+ * 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("$FreeBSD$");
+
+#include "SYS.h"
+
+	.globl	_C_LABEL(_end)
+
+	.data
+	.align	3
+	.global	_C_LABEL(curbrk)
+	.type	_C_LABEL(curbrk), %object
+_C_LABEL(curbrk):
+	.quad	_C_LABEL(_end)
+
+	.text
+/*
+ * void *sbrk(intptr_t incr);
+ */
+ENTRY(_sbrk)
+	WEAK_REFERENCE(_sbrk, sbrk)
+
+	/* Load the address of curbrk */
+	la	a3, curbrk
+
+	/* Get the current brk address */
+	ld	a2, 0(a3)
+
+	/* Calculate the new value */
+	add	a0, a0, a2
+	mv	a4, a0
+
+	/* Update for this value, will overwrite a0 and a1 */
+	_SYSCALL(break)
+	bnez	t0, cerror
+
+	/* Load the old value to return */
+	ld	a0, 0(a3)
+
+	/* Store the new curbrk value */
+	sd	a4, 0(a3)
+
+	ret
+END(_sbrk)
diff --git a/lib/libc/riscv/sys/shmat.S b/lib/libc/riscv/sys/shmat.S
new file mode 100644
index 0000000..3a5b4bc
--- /dev/null
+++ b/lib/libc/riscv/sys/shmat.S
@@ -0,0 +1,40 @@
+/*-
+ * 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("$FreeBSD$");
+
+#include "SYS.h"
+
+RSYSCALL(shmat)
diff --git a/lib/libc/riscv/sys/sigreturn.S b/lib/libc/riscv/sys/sigreturn.S
new file mode 100644
index 0000000..dfaee7a
--- /dev/null
+++ b/lib/libc/riscv/sys/sigreturn.S
@@ -0,0 +1,40 @@
+/*-
+ * 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("$FreeBSD$");
+
+#include "SYS.h"
+
+RSYSCALL(sigreturn)
diff --git a/lib/libc/riscv/sys/syscall.S b/lib/libc/riscv/sys/syscall.S
new file mode 100644
index 0000000..8a007f8
--- /dev/null
+++ b/lib/libc/riscv/sys/syscall.S
@@ -0,0 +1,40 @@
+/*-
+ * 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("$FreeBSD$");
+
+#include "SYS.h"
+
+RSYSCALL(syscall)
diff --git a/lib/libc/riscv/sys/vfork.S b/lib/libc/riscv/sys/vfork.S
new file mode 100644
index 0000000..a505780
--- /dev/null
+++ b/lib/libc/riscv/sys/vfork.S
@@ -0,0 +1,51 @@
+/*-
+ * 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("$FreeBSD$");
+#include "SYS.h"
+
+ENTRY(__sys_vfork)
+	WEAK_REFERENCE(__sys_vfork, vfork)
+	WEAK_REFERENCE(__sys_vfork, _vfork)
+	mv	a2, ra
+
+	_SYSCALL(vfork)
+	bnez	t0, cerror
+	addi	a1, a1, -1
+	and	a0, a0, a1
+	mv	ra, a2
+
+	ret
+END(__sys_vfork)