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[PATCH v7 11/17] RISC-V: Linux Syscall Interface
- From: Palmer Dabbelt <palmer at dabbelt dot com>
- To: libc-alpha at sourceware dot org, joseph at codesourcery dot com
- Cc: Palmer Dabbelt <palmer at dabbelt dot com>
- Date: Fri, 26 Jan 2018 19:57:38 -0800
- Subject: [PATCH v7 11/17] RISC-V: Linux Syscall Interface
- Authentication-results: sourceware.org; auth=none
- References: <20180127035744.10058-1-palmer@dabbelt.com>
Contains the Linux system call interface, as well as the definitions of
a handful of system calls.
2018-01-26 Palmer Dabbelt <palmer@sifive.com>
* sysdeps/riscv/nptl/nptl-sysdep.S: New file.
* sysdeps/unix/sysv/linux/riscv/arch-fork.h: Likewise.
* sysdeps/unix/sysv/linux/riscv/clone.S: Likewise.
* sysdeps/unix/sysv/linux/riscv/profil-counter.h: Likewise.
* sysdeps/unix/sysv/linux/riscv/pt-vfork.S: Likewise.
* sysdeps/unix/sysv/linux/riscv/syscall.c: Likewise.
* sysdeps/unix/sysv/linux/riscv/sysdep.S: Likewise.
* sysdeps/unix/sysv/linux/riscv/sysdep.h: Likewise.
* sysdeps/unix/sysv/linux/riscv/vfork.S: Likewise.
---
sysdeps/riscv/nptl/nptl-sysdep.S | 2 +
sysdeps/unix/sysv/linux/riscv/arch-fork.h | 26 ++
sysdeps/unix/sysv/linux/riscv/clone.S | 86 +++++++
sysdeps/unix/sysv/linux/riscv/profil-counter.h | 31 +++
sysdeps/unix/sysv/linux/riscv/pt-vfork.S | 1 +
sysdeps/unix/sysv/linux/riscv/syscall.c | 35 +++
sysdeps/unix/sysv/linux/riscv/sysdep.S | 51 ++++
sysdeps/unix/sysv/linux/riscv/sysdep.h | 325 +++++++++++++++++++++++++
sysdeps/unix/sysv/linux/riscv/vfork.S | 44 ++++
9 files changed, 601 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/profil-counter.h
create mode 100644 sysdeps/unix/sysv/linux/riscv/pt-vfork.S
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 000000000000..3f5c2a364afd
--- /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 000000000000..f6f5d733439b
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/riscv/arch-fork.h
@@ -0,0 +1,26 @@
+/* Internal definitions for thread-friendly fork implementation. Linux/RISC-V.
+ Copyright (C) 2002-2018 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/>. */
+
+#include <sched.h>
+#include <sysdep.h>
+#include <tls.h>
+
+#define ARCH_FORK() \
+ INLINE_SYSCALL (clone, 5, \
+ CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID | SIGCHLD, 0, \
+ NULL, NULL, &THREAD_SELF->tid)
diff --git a/sysdeps/unix/sysv/linux/riscv/clone.S b/sysdeps/unix/sysv/linux/riscv/clone.S
new file mode 100644
index 000000000000..392af72b55da
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/riscv/clone.S
@@ -0,0 +1,86 @@
+/* Wrapper around clone system call. RISC-V version.
+ Copyright (C) 1996-2018 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/>. */
+
+/* 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. */
+ li a7, __NR_exit
+ scall
+
+ END (__thread_start)
+
+libc_hidden_def (__clone)
+weak_alias (__clone, clone)
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 000000000000..748019ee1b9d
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/riscv/profil-counter.h
@@ -0,0 +1,31 @@
+/* Low-level statistical profiling support function. Linux/RISC-V version.
+ Copyright (C) 1996-2018 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/>. */
+
+#include <signal.h>
+#include <sigcontextinfo.h>
+
+static void
+__profil_counter (int signo, const SIGCONTEXT scp)
+{
+ profil_count ((void *) GET_PC (scp));
+
+ /* This is a hack to prevent the compiler from implementing the
+ above function call as a sibcall. The sibcall would overwrite
+ the signal context. */
+ asm volatile ("");
+}
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 000000000000..1cc893170070
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/riscv/pt-vfork.S
@@ -0,0 +1 @@
+/* Not needed. */
diff --git a/sysdeps/unix/sysv/linux/riscv/syscall.c b/sysdeps/unix/sysv/linux/riscv/syscall.c
new file mode 100644
index 000000000000..6589dde385e0
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/riscv/syscall.c
@@ -0,0 +1,35 @@
+/* system call interface. Linux/RISC-V version.
+ Copyright (C) 2001-2018 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/>. */
+
+#include <sysdep.h>
+
+long int
+syscall (long int syscall_number, long int arg1, long int arg2, long int arg3,
+ long int arg4, long int arg5, long int arg6, long int arg7)
+{
+ long int 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))
+ 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 000000000000..0d9c0b5bd907
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/riscv/sysdep.S
@@ -0,0 +1,51 @@
+/* syscall error handlers
+ Copyright (C) 2011-2018 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/>. */
+
+#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 000000000000..5470ea3d2a68
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/riscv/sysdep.h
@@ -0,0 +1,325 @@
+/* Assembly macros for RISC-V.
+ Copyright (C) 2011-2018
+ 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)
+
+# define L(label) .L ## label
+
+/* Performs a system call, handling errors by setting errno. Linux indicates
+ errors by setting a0 to a value between -1 and -4095. */
+# undef PSEUDO
+# define PSEUDO(name, syscall_name, args) \
+ .text; \
+ .align 2; \
+ ENTRY (name); \
+ li a7, SYS_ify (syscall_name); \
+ scall; \
+ li a7, -4096; \
+ bgtu a0, a7, .Lsyscall_error ## name;
+
+# undef PSEUDO_END
+# define PSEUDO_END(sym) \
+ SYSCALL_ERROR_HANDLER (sym) \
+ ret; \
+ END (sym)
+
+# if !IS_IN (libc)
+# if RTLD_PRIVATE_ERRNO
+# define SYSCALL_ERROR_HANDLER(name) \
+.Lsyscall_error ## name: \
+ li t1, -4096; \
+ neg a0, a0; \
+ sw a0, rtld_errno, t1; \
+ li a0, -1;
+# elif defined (__PIC__)
+# define SYSCALL_ERROR_HANDLER(name) \
+.Lsyscall_error ## name: \
+ la.tls.ie t1, errno; \
+ add t1, t1, tp; \
+ neg a0, a0; \
+ sw a0, 0(t1); \
+ li a0, -1;
+# else
+# define SYSCALL_ERROR_HANDLER(name) \
+.Lsyscall_error ## name: \
+ lui t1, %tprel_hi(errno); \
+ add t1, t1, tp, %tprel_add(errno); \
+ neg a0, a0; \
+ sw a0, %tprel_lo(errno)(t1); \
+ li a0, -1;
+# endif
+# else
+# define SYSCALL_ERROR_HANDLER(name) \
+.Lsyscall_error ## name: \
+ j __syscall_error;
+# endif
+
+/* Performs a system call, not setting errno. */
+# undef PSEUDO_NEORRNO
+# define PSEUDO_NOERRNO(name, syscall_name, args) \
+ .align 2; \
+ ENTRY (name); \
+ li a7, SYS_ify (syscall_name); \
+ scall;
+
+# undef PSEUDO_END_NOERRNO
+# define PSEUDO_END_NOERRNO(name) \
+ END (name)
+
+# undef ret_NOERRNO
+# define ret_NOERRNO ret
+
+/* Perfroms a system call, returning the error code. */
+# undef PSEUDO_ERRVAL
+# define PSEUDO_ERRVAL(name, syscall_name, args) \
+ PSEUDO_NOERRNO (name, syscall_name, args) \
+ neg a0, a0;
+
+# undef PSEUDO_END_ERRVAL
+# define PSEUDO_END_ERRVAL(name) \
+ END (name)
+
+# undef ret_ERRVAL
+# define ret_ERRVAL ret
+
+#endif /* __ASSEMBLER__ */
+
+/* In order to get __set_errno() definition in INLINE_SYSCALL. */
+#ifndef __ASSEMBLER__
+# include <errno.h>
+#endif
+
+#include <sysdeps/unix/sysdep.h>
+
+#undef SYS_ify
+#define SYS_ify(syscall_name) __NR_##syscall_name
+
+#ifndef __ASSEMBLER__
+
+/* List of system calls which are supported as vsyscalls. */
+# define HAVE_CLOCK_GETRES_VSYSCALL 1
+# define HAVE_CLOCK_GETTIME_VSYSCALL 1
+# define HAVE_GETTIMEOFDAY_VSYSCALL 1
+# define HAVE_GETCPU_VSYSCALL 1
+
+/* 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 int __sys_result = INTERNAL_SYSCALL (name, err, nr, args); \
+ if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (__sys_result, ))) \
+ { \
+ __set_errno (INTERNAL_SYSCALL_ERRNO (__sys_result, )); \
+ __sys_result = (unsigned long) -1; \
+ } \
+ __sys_result; })
+
+# define INTERNAL_SYSCALL_DECL(err) do { } while (0)
+
+# define INTERNAL_SYSCALL_ERROR_P(val, err) \
+ ((unsigned long int) (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 int _sys_result; \
+ \
+ { \
+ register long int __a7 asm ("a7") = number; \
+ register long int __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 int _sys_result; \
+ \
+ { \
+ register long int __a7 asm ("a7") = number; \
+ register long int __a0 asm ("a0") = (long int) (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 int _sys_result; \
+ \
+ { \
+ register long int __a7 asm ("a7") = number; \
+ register long int __a0 asm ("a0") = (long int) (arg0); \
+ register long int __a1 asm ("a1") = (long int) (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 int _sys_result; \
+ \
+ { \
+ register long int __a7 asm ("a7") = number; \
+ register long int __a0 asm ("a0") = (long int) (arg0); \
+ register long int __a1 asm ("a1") = (long int) (arg1); \
+ register long int __a2 asm ("a2") = (long int) (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 int _sys_result; \
+ \
+ { \
+ register long int __a7 asm ("a7") = number; \
+ register long int __a0 asm ("a0") = (long int) (arg0); \
+ register long int __a1 asm ("a1") = (long int) (arg1); \
+ register long int __a2 asm ("a2") = (long int) (arg2); \
+ register long int __a3 asm ("a3") = (long int) (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 int _sys_result; \
+ \
+ { \
+ register long int __a7 asm ("a7") = number; \
+ register long int __a0 asm ("a0") = (long int) (arg0); \
+ register long int __a1 asm ("a1") = (long int) (arg1); \
+ register long int __a2 asm ("a2") = (long int) (arg2); \
+ register long int __a3 asm ("a3") = (long int) (arg3); \
+ register long int __a4 asm ("a4") = (long int) (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 int _sys_result; \
+ \
+ { \
+ register long int __a7 asm ("a7") = number; \
+ register long int __a0 asm ("a0") = (long int) (arg0); \
+ register long int __a1 asm ("a1") = (long int) (arg1); \
+ register long int __a2 asm ("a2") = (long int) (arg2); \
+ register long int __a3 asm ("a3") = (long int) (arg3); \
+ register long int __a4 asm ("a4") = (long int) (arg4); \
+ register long int __a5 asm ("a5") = (long int) (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 int _sys_result; \
+ \
+ { \
+ register long int __a7 asm ("a7") = number; \
+ register long int __a0 asm ("a0") = (long int) (arg0); \
+ register long int __a1 asm ("a1") = (long int) (arg1); \
+ register long int __a2 asm ("a2") = (long int) (arg2); \
+ register long int __a3 asm ("a3") = (long int) (arg3); \
+ register long int __a4 asm ("a4") = (long int) (arg4); \
+ register long int __a5 asm ("a5") = (long int) (arg5); \
+ register long int __a6 asm ("a6") = (long int) (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"
+
+extern long int __syscall_error (long int neg_errno);
+
+#endif /* ! __ASSEMBLER__ */
+
+/* Pointer mangling is not supported. */
+#define PTR_MANGLE(var) (void) (var)
+#define PTR_DEMANGLE(var) (void) (var)
+
+#endif /* linux/riscv/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 000000000000..6c53e93a928d
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/riscv/vfork.S
@@ -0,0 +1,44 @@
+/* vfork for Linux, RISC-V version.
+ Copyright (C) 2005-2018 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/>. */
+
+/* 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)
--
2.13.6