[glibc] or1k: Add prctl wrapper to unwrap variadic args

[Stafford Horne <shorne@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=ad05a42370fa09062ff2b450fb69905d9f407643

commit ad05a42370fa09062ff2b450fb69905d9f407643
Author: Stafford Horne <shorne@gmail.com>
Date:   Tue Mar 19 21:01:24 2024 +0000

    or1k: Add prctl wrapper to unwrap variadic args
    
    On OpenRISC variadic functions and regular functions have different
    calling conventions so this wrapper is needed to translate.  This
    wrapper is copied from x86_64/x32.  I don't know the build system enough
    to find a cleaner way to share the code between x86_64/x32 and or1k
    (maybe Implies?), so I went with the straight copy.
    
    This fixes test failures:
    
      misc/tst-prctl
      nptl/tst-setgetname

Diff:
---
 sysdeps/unix/sysv/linux/or1k/prctl.c | 42 ++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/sysdeps/unix/sysv/linux/or1k/prctl.c b/sysdeps/unix/sysv/linux/or1k/prctl.c
new file mode 100644
index 0000000000..1aa707d175
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/or1k/prctl.c
@@ -0,0 +1,42 @@
+/* prctl - Linux specific syscall.  OpenRISC version.
+   Copyright (C) 2024 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
+   <https://www.gnu.org/licenses/>.  */
+
+#include <sysdep.h>
+#include <stdarg.h>
+#include <sys/prctl.h>
+
+/* Unconditionally read all potential arguments.  This may pass
+   garbage values to the kernel, but avoids the need for teaching
+   glibc the argument counts of individual options (including ones
+   that are added to the kernel in the future).  */
+
+int
+__prctl (int option, ...)
+{
+  va_list arg;
+  va_start (arg, option);
+  unsigned long int arg2 = va_arg (arg, unsigned long int);
+  unsigned long int arg3 = va_arg (arg, unsigned long int);
+  unsigned long int arg4 = va_arg (arg, unsigned long int);
+  unsigned long int arg5 = va_arg (arg, unsigned long int);
+  va_end (arg);
+  return INLINE_SYSCALL_CALL (prctl, option, arg2, arg3, arg4, arg5);
+}
+
+libc_hidden_def (__prctl)
+weak_alias (__prctl, prctl)