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[PATCH 10/12] RISC-V: Linux Syscall Interface
- From: Palmer Dabbelt <palmer at dabbelt dot com>
- To: libc-alpha at sourceware dot org
- Cc: Andrew Waterman <andrew at sifive dot com>
- Cc: patches at groups dot riscv dot org
- Cc: Darius Rad <darius at bluespec dot com>
- Cc: Palmer Dabbelt <palmer at dabbelt dot com>
- Date: Wed, 14 Jun 2017 11:30:46 -0700
- Subject: [PATCH 10/12] RISC-V: Linux Syscall Interface
- Authentication-results: sourceware.org; auth=none
- References: <20170614183048.11040-1-palmer@dabbelt.com>
Contains the Linux system call interface, as well as the definitions of
a handful of system calls.
---
sysdeps/riscv/nptl/nptl-sysdep.S | 2 +
sysdeps/unix/sysv/linux/riscv/arch-fork.h | 1 +
sysdeps/unix/sysv/linux/riscv/clone.S | 86 ++++++++
sysdeps/unix/sysv/linux/riscv/getmsg.c | 1 +
sysdeps/unix/sysv/linux/riscv/kernel-features.h | 22 ++
sysdeps/unix/sysv/linux/riscv/profil-counter.h | 2 +
sysdeps/unix/sysv/linux/riscv/pt-vfork.S | 0
sysdeps/unix/sysv/linux/riscv/putmsg.c | 1 +
sysdeps/unix/sysv/linux/riscv/rv32/lockf64.c | 1 +
sysdeps/unix/sysv/linux/riscv/rv32/readahead.c | 1 +
sysdeps/unix/sysv/linux/riscv/syscall.c | 38 ++++
sysdeps/unix/sysv/linux/riscv/sysdep.S | 51 +++++
sysdeps/unix/sysv/linux/riscv/sysdep.h | 262 ++++++++++++++++++++++++
sysdeps/unix/sysv/linux/riscv/vfork.S | 44 ++++
14 files changed, 512 insertions(+)
create mode 100644 sysdeps/riscv/nptl/nptl-sysdep.S
create mode 100644 sysdeps/unix/sysv/linux/riscv/arch-fork.h
create mode 100644 sysdeps/unix/sysv/linux/riscv/clone.S
create mode 100644 sysdeps/unix/sysv/linux/riscv/getmsg.c
create mode 100644 sysdeps/unix/sysv/linux/riscv/kernel-features.h
create mode 100644 sysdeps/unix/sysv/linux/riscv/profil-counter.h
create mode 100644 sysdeps/unix/sysv/linux/riscv/pt-vfork.S
create mode 100644 sysdeps/unix/sysv/linux/riscv/putmsg.c
create mode 100644 sysdeps/unix/sysv/linux/riscv/rv32/lockf64.c
create mode 100644 sysdeps/unix/sysv/linux/riscv/rv32/readahead.c
create mode 100644 sysdeps/unix/sysv/linux/riscv/syscall.c
create mode 100644 sysdeps/unix/sysv/linux/riscv/sysdep.S
create mode 100644 sysdeps/unix/sysv/linux/riscv/sysdep.h
create mode 100644 sysdeps/unix/sysv/linux/riscv/vfork.S
diff --git a/sysdeps/riscv/nptl/nptl-sysdep.S b/sysdeps/riscv/nptl/nptl-sysdep.S
new file mode 100644
index 0000000000..3f5c2a364a
--- /dev/null
+++ b/sysdeps/riscv/nptl/nptl-sysdep.S
@@ -0,0 +1,2 @@
+/* Pull in __syscall_error. */
+#include <sysdep.S>
diff --git a/sysdeps/unix/sysv/linux/riscv/arch-fork.h b/sysdeps/unix/sysv/linux/riscv/arch-fork.h
new file mode 100644
index 0000000000..5f945378ee
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/riscv/arch-fork.h
@@ -0,0 +1 @@
+#include <sysdeps/unix/sysv/linux/i386/arch-fork.h>
diff --git a/sysdeps/unix/sysv/linux/riscv/clone.S b/sysdeps/unix/sysv/linux/riscv/clone.S
new file mode 100644
index 0000000000..716ab877f5
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/riscv/clone.S
@@ -0,0 +1,86 @@
+/* Copyright (C) 1996-2017 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ralf Baechle <ralf@linux-mips.org>, 1996.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+/* clone() is even more special than fork() as it mucks with stacks
+ and invokes a function in the right context after its all over. */
+
+#include <sys/asm.h>
+#include <sysdep.h>
+#define _ERRNO_H 1
+#include <bits/errno.h>
+#include <tls.h>
+#include "tcb-offsets.h"
+
+/* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg,
+ void *parent_tidptr, void *tls, void *child_tidptr) */
+
+ .text
+LEAF(__clone)
+
+ /* Sanity check arguments. */
+ beqz a0,L(invalid) /* No NULL function pointers. */
+ beqz a1,L(invalid) /* No NULL stack pointers. */
+
+ addi a1,a1,-16 /* Reserve argument save space. */
+ REG_S a0,0(a1) /* Save function pointer. */
+ REG_S a3,SZREG(a1) /* Save argument pointer. */
+
+ /* The syscall expects the args to be in different slots. */
+ mv a0,a2
+ mv a2,a4
+ mv a3,a5
+ mv a4,a6
+
+ /* Do the system call */
+ li a7,__NR_clone
+ scall
+
+ bltz a0,L(error)
+ beqz a0,L(thread_start)
+
+ /* Successful return from the parent */
+ ret
+
+L(invalid):
+ li a0, -EINVAL
+ /* Something bad happened -- no child created */
+L(error):
+ j __syscall_error
+ END(__clone)
+
+/* Load up the arguments to the function. Put this block of code in
+ its own function so that we can terminate the stack trace with our
+ debug info. */
+
+ENTRY(__thread_start)
+L(thread_start):
+ /* Restore the arg for user's function. */
+ REG_L a1,0(sp) /* Function pointer. */
+ REG_L a0,SZREG(sp) /* Argument pointer. */
+
+ /* Call the user's function. */
+ jalr a1
+
+ /* Call _exit with the function's return value. */
+ j _exit
+
+ END(__thread_start)
+
+libc_hidden_def(__clone)
+weak_alias (__clone, clone)
diff --git a/sysdeps/unix/sysv/linux/riscv/getmsg.c b/sysdeps/unix/sysv/linux/riscv/getmsg.c
new file mode 100644
index 0000000000..3a1fa08525
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/riscv/getmsg.c
@@ -0,0 +1 @@
+#include <sysdeps/unix/sysv/linux/i386/getmsg.c>
diff --git a/sysdeps/unix/sysv/linux/riscv/kernel-features.h b/sysdeps/unix/sysv/linux/riscv/kernel-features.h
new file mode 100644
index 0000000000..2db504b53b
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/riscv/kernel-features.h
@@ -0,0 +1,22 @@
+/* Copyright (C) 2014, 2017 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library. If not, see
+ <http://www.gnu.org/licenses/>. */
+
+#define __ASSUME_ACCEPT4_SYSCALL 1
+#define __ASSUME_RECVMMSG_SYSCALL 1
+#define __ASSUME_SENDMMSG_SYSCALL 1
+
+#include_next <kernel-features.h>
diff --git a/sysdeps/unix/sysv/linux/riscv/profil-counter.h b/sysdeps/unix/sysv/linux/riscv/profil-counter.h
new file mode 100644
index 0000000000..8a6a0bcf3d
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/riscv/profil-counter.h
@@ -0,0 +1,2 @@
+/* We can use the ix86 version. */
+#include <sysdeps/unix/sysv/linux/i386/profil-counter.h>
diff --git a/sysdeps/unix/sysv/linux/riscv/pt-vfork.S b/sysdeps/unix/sysv/linux/riscv/pt-vfork.S
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/sysdeps/unix/sysv/linux/riscv/putmsg.c b/sysdeps/unix/sysv/linux/riscv/putmsg.c
new file mode 100644
index 0000000000..ebc1680ca7
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/riscv/putmsg.c
@@ -0,0 +1 @@
+#include <sysdeps/unix/sysv/linux/i386/putmsg.c>
diff --git a/sysdeps/unix/sysv/linux/riscv/rv32/lockf64.c b/sysdeps/unix/sysv/linux/riscv/rv32/lockf64.c
new file mode 100644
index 0000000000..a88f5a784a
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/riscv/rv32/lockf64.c
@@ -0,0 +1 @@
+#include <sysdeps/unix/sysv/linux/i386/lockf64.c>
diff --git a/sysdeps/unix/sysv/linux/riscv/rv32/readahead.c b/sysdeps/unix/sysv/linux/riscv/rv32/readahead.c
new file mode 100644
index 0000000000..80170c3e8a
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/riscv/rv32/readahead.c
@@ -0,0 +1 @@
+#include <sysdeps/unix/sysv/linux/arm/readahead.c>
diff --git a/sysdeps/unix/sysv/linux/riscv/syscall.c b/sysdeps/unix/sysv/linux/riscv/syscall.c
new file mode 100644
index 0000000000..f37a8b58aa
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/riscv/syscall.c
@@ -0,0 +1,38 @@
+/* Copyright (C) 2001-2003, 2005, 2017 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#include <sysdep.h>
+
+long
+syscall (long syscall_number, long arg1, long arg2, long arg3, long arg4,
+ long arg5, long arg6, long arg7)
+{
+ long ret;
+ INTERNAL_SYSCALL_DECL (err);
+
+ ret = INTERNAL_SYSCALL_NCS (syscall_number, err, 7, arg1, arg2, arg3, arg4,
+ arg5, arg6, arg7);
+
+ if (INTERNAL_SYSCALL_ERROR_P (ret, err))
+ {
+ extern long __syscall_error (long neg_errno);
+ return __syscall_error (ret);
+ }
+
+ return ret;
+}
diff --git a/sysdeps/unix/sysv/linux/riscv/sysdep.S b/sysdeps/unix/sysv/linux/riscv/sysdep.S
new file mode 100644
index 0000000000..a32ac69088
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/riscv/sysdep.S
@@ -0,0 +1,51 @@
+/* Copyright (C) 2011-2017 Free Software Foundation, Inc.
+ Contributed by Andrew Waterman (andrew@sifive.com).
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library. If not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <sysdep.h>
+
+#if IS_IN (libc)
+# define errno __libc_errno
+#endif
+
+ENTRY (__syscall_error)
+ mv t0, ra
+ /* Fall through to __syscall_set_errno. */
+END (__syscall_error)
+
+/* Non-standard calling convention: argument in a0, return address in t0,
+ and clobber only t1. */
+ENTRY (__syscall_set_errno)
+ /* We got here because a0 < 0, but only codes in the range [-4095, -1]
+ represent errors. Otherwise, just return the result normally. */
+ li t1, -4096
+ bleu a0, t1, 1f
+ neg a0, a0
+#if RTLD_PRIVATE_ERRNO
+ sw a0, rtld_errno, t1
+#elif defined(__PIC__)
+ la.tls.ie t1, errno
+ add t1, t1, tp
+ sw a0, 0(t1)
+#else
+ lui t1, %tprel_hi(errno)
+ add t1, t1, tp, %tprel_add(errno)
+ sw a0, %tprel_lo(errno)(t1)
+#endif
+ li a0, -1
+1: jr t0
+END (__syscall_set_errno)
diff --git a/sysdeps/unix/sysv/linux/riscv/sysdep.h b/sysdeps/unix/sysv/linux/riscv/sysdep.h
new file mode 100644
index 0000000000..eddb0a586e
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/riscv/sysdep.h
@@ -0,0 +1,262 @@
+/* Copyright (C) 2011-2014, 2017
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library. If not, see
+ <http://www.gnu.org/licenses/>. */
+
+#ifndef _LINUX_RISCV_SYSDEP_H
+#define _LINUX_RISCV_SYSDEP_H 1
+
+#include <sysdeps/unix/sysv/linux/generic/sysdep.h>
+#include <tls.h>
+
+#ifdef __ASSEMBLER__
+
+#include <sys/asm.h>
+
+#define ENTRY(name) LEAF(name)
+
+#undef PSEUDO_END
+#define PSEUDO_END(sym) END(sym)
+
+#define PSEUDO_NOERRNO(name, syscall_name, args) \
+ .align 2; \
+ ENTRY(name) \
+ li a7, SYS_ify(syscall_name); \
+ scall
+
+#define ret_NOERRNO ret
+
+#define PSEUDO_ERRVAL(name, syscall_name, args) \
+ PSEUDO_NOERRNO(name, syscall_name, args)
+
+#define ret_ERRVAL ret
+
+#define L(label) .L ## label
+
+#define PSEUDO(name, syscall_name, args) \
+ .align 2; \
+ 99: j __syscall_error; \
+ ENTRY(name) \
+ li a7, SYS_ify(syscall_name); \
+ scall; \
+ bltz a0, 99b; \
+L(syse1):
+
+#endif /* __ASSEMBLER__ */
+
+#include <sysdeps/unix/sysdep.h>
+
+#undef SYS_ify
+#define SYS_ify(syscall_name) __NR_##syscall_name
+
+#ifndef __ASSEMBLER__
+
+/* Define a macro which expands into the inline wrapper code for a system
+ call. */
+#undef INLINE_SYSCALL
+#define INLINE_SYSCALL(name, nr, args...) \
+ ({ INTERNAL_SYSCALL_DECL(err); \
+ long result = INTERNAL_SYSCALL (name, err, nr, args); \
+ register long __a0 asm ("a0") = result; \
+ if (__a0 < 0) \
+ __asm__ volatile ("call t0, __syscall_set_errno" \
+ : "+r" (__a0) : : "t0", "t1", "t2"); \
+ __a0; })
+
+/* Set error number and return -1. Return the internal function,
+ __syscall_error, which sets errno from the negative error number
+ and returns -1. */
+#undef INLINE_SYSCALL_ERROR_RETURN_VALUE
+#define INLINE_SYSCALL_ERROR_RETURN_VALUE(resultvar) \
+ ({ extern int __syscall_error (long neg_errno); \
+ __syscall_error (-(resultvar)); })
+
+#define INTERNAL_SYSCALL_DECL(err) do { } while (0)
+
+#define INTERNAL_SYSCALL_ERROR_P(val, err) ((unsigned long) (val) > -4096UL)
+
+#define INTERNAL_SYSCALL_ERRNO(val, err) (-val)
+
+#define INTERNAL_SYSCALL(name, err, nr, args...) \
+ internal_syscall##nr (SYS_ify (name), err, args)
+
+#define INTERNAL_SYSCALL_NCS(number, err, nr, args...) \
+ internal_syscall##nr (number, err, args)
+
+#define internal_syscall0(number, err, dummy...) \
+({ \
+ long _sys_result; \
+ \
+ { \
+ register long __a7 asm("a7") = number; \
+ register long __a0 asm("a0"); \
+ __asm__ volatile ( \
+ "scall\n\t" \
+ : "=r" (__a0) \
+ : "r" (__a7) \
+ : __SYSCALL_CLOBBERS); \
+ _sys_result = __a0; \
+ } \
+ _sys_result; \
+})
+
+#define internal_syscall1(number, err, arg0) \
+({ \
+ long _sys_result; \
+ \
+ { \
+ register long __a7 asm("a7") = number; \
+ register long __a0 asm("a0") = (long) (arg0); \
+ __asm__ volatile ( \
+ "scall\n\t" \
+ : "+r" (__a0) \
+ : "r" (__a7) \
+ : __SYSCALL_CLOBBERS); \
+ _sys_result = __a0; \
+ } \
+ _sys_result; \
+})
+
+#define internal_syscall2(number, err, arg0, arg1) \
+({ \
+ long _sys_result; \
+ \
+ { \
+ register long __a7 asm("a7") = number; \
+ register long __a0 asm("a0") = (long) (arg0); \
+ register long __a1 asm("a1") = (long) (arg1); \
+ __asm__ volatile ( \
+ "scall\n\t" \
+ : "+r" (__a0) \
+ : "r" (__a7), "r"(__a1) \
+ : __SYSCALL_CLOBBERS); \
+ _sys_result = __a0; \
+ } \
+ _sys_result; \
+})
+
+#define internal_syscall3(number, err, arg0, arg1, arg2) \
+({ \
+ long _sys_result; \
+ \
+ { \
+ register long __a7 asm("a7") = number; \
+ register long __a0 asm("a0") = (long) (arg0); \
+ register long __a1 asm("a1") = (long) (arg1); \
+ register long __a2 asm("a2") = (long) (arg2); \
+ __asm__ volatile ( \
+ "scall\n\t" \
+ : "+r" (__a0) \
+ : "r" (__a7), "r"(__a1), "r"(__a2) \
+ : __SYSCALL_CLOBBERS); \
+ _sys_result = __a0; \
+ } \
+ _sys_result; \
+})
+
+#define internal_syscall4(number, err, arg0, arg1, arg2, arg3) \
+({ \
+ long _sys_result; \
+ \
+ { \
+ register long __a7 asm("a7") = number; \
+ register long __a0 asm("a0") = (long) (arg0); \
+ register long __a1 asm("a1") = (long) (arg1); \
+ register long __a2 asm("a2") = (long) (arg2); \
+ register long __a3 asm("a3") = (long) (arg3); \
+ __asm__ volatile ( \
+ "scall\n\t" \
+ : "+r" (__a0) \
+ : "r" (__a7), "r"(__a1), "r"(__a2), "r"(__a3) \
+ : __SYSCALL_CLOBBERS); \
+ _sys_result = __a0; \
+ } \
+ _sys_result; \
+})
+
+#define internal_syscall5(number, err, arg0, arg1, arg2, arg3, arg4) \
+({ \
+ long _sys_result; \
+ \
+ { \
+ register long __a7 asm("a7") = number; \
+ register long __a0 asm("a0") = (long) (arg0); \
+ register long __a1 asm("a1") = (long) (arg1); \
+ register long __a2 asm("a2") = (long) (arg2); \
+ register long __a3 asm("a3") = (long) (arg3); \
+ register long __a4 asm("a4") = (long) (arg4); \
+ __asm__ volatile ( \
+ "scall\n\t" \
+ : "+r" (__a0) \
+ : "r" (__a7), "r"(__a1), "r"(__a2), "r"(__a3), "r"(__a4) \
+ : __SYSCALL_CLOBBERS); \
+ _sys_result = __a0; \
+ } \
+ _sys_result; \
+})
+
+#define internal_syscall6(number, err, arg0, arg1, arg2, arg3, arg4, arg5) \
+({ \
+ long _sys_result; \
+ \
+ { \
+ register long __a7 asm("a7") = number; \
+ register long __a0 asm("a0") = (long) (arg0); \
+ register long __a1 asm("a1") = (long) (arg1); \
+ register long __a2 asm("a2") = (long) (arg2); \
+ register long __a3 asm("a3") = (long) (arg3); \
+ register long __a4 asm("a4") = (long) (arg4); \
+ register long __a5 asm("a5") = (long) (arg5); \
+ __asm__ volatile ( \
+ "scall\n\t" \
+ : "+r" (__a0) \
+ : "r" (__a7), "r"(__a1), "r"(__a2), "r"(__a3), "r"(__a4), "r"(__a5) \
+ : __SYSCALL_CLOBBERS); \
+ _sys_result = __a0; \
+ } \
+ _sys_result; \
+})
+
+#define internal_syscall7(number, err, arg0, arg1, arg2, arg3, arg4, arg5, arg6) \
+({ \
+ long _sys_result; \
+ \
+ { \
+ register long __a7 asm("a7") = number; \
+ register long __a0 asm("a0") = (long) (arg0); \
+ register long __a1 asm("a1") = (long) (arg1); \
+ register long __a2 asm("a2") = (long) (arg2); \
+ register long __a3 asm("a3") = (long) (arg3); \
+ register long __a4 asm("a4") = (long) (arg4); \
+ register long __a5 asm("a5") = (long) (arg5); \
+ register long __a6 asm("a6") = (long) (arg6); \
+ __asm__ volatile ( \
+ "scall\n\t" \
+ : "+r" (__a0) \
+ : "r" (__a7), "r"(__a1), "r"(__a2), "r"(__a3), "r"(__a4), "r"(__a5), "r"(__a6) \
+ : __SYSCALL_CLOBBERS); \
+ _sys_result = __a0; \
+ } \
+ _sys_result; \
+})
+
+#define __SYSCALL_CLOBBERS "memory"
+#endif /* ! __ASSEMBLER__ */
+
+/* Pointer mangling is not supported. */
+#define PTR_MANGLE(var) (void) (var)
+#define PTR_DEMANGLE(var) (void) (var)
+
+#endif /* linux/mips/sysdep.h */
diff --git a/sysdeps/unix/sysv/linux/riscv/vfork.S b/sysdeps/unix/sysv/linux/riscv/vfork.S
new file mode 100644
index 0000000000..ff7176a40f
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/riscv/vfork.S
@@ -0,0 +1,44 @@
+/* Copyright (C) 2005, 2017 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+/* vfork() is just a special case of clone(). */
+
+#include <sys/asm.h>
+#include <sysdep.h>
+#define __ASSEMBLY__
+#include <linux/sched.h>
+#include <asm/signal.h>
+
+ .text
+LEAF(__libc_vfork)
+
+ li a0, (CLONE_VFORK | CLONE_VM | SIGCHLD)
+ mv a1, sp
+
+ li a7, __NR_clone
+ scall
+
+ bltz a0, 1f
+ ret
+
+1: j __syscall_error
+END(__libc_vfork)
+
+weak_alias (__libc_vfork, vfork)
+strong_alias (__libc_vfork, __vfork)
+libc_hidden_def (__vfork)
--
2.13.0