RISC-V: Linux Syscall Interface

Contains the Linux system call interface, as well as the definitions of
a handful of system calls.

2018-01-29  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.

1 files changed, 51 insertions, 0 deletions

diff --git a/sysdeps/unix/sysv/linux/riscv/sysdep.S b/sysdeps/unix/sysv/linux/riscv/sysdep.S
new file mode 100644
index 0000000000..0d9c0b5bd9
--- /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)