Re: [PATCH 4/4] or1k: Add prctl wrapper to unwrap variadic args

[Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>]

On 19/03/24 18:42, Stafford Horne wrote:
> 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.

It looks ok, the old way of cross-reference ABIs implementations only
add complications. 

> 
> This fixes test failures:
> 
>   misc/tst-prctl
>   nptl/tst-setgetname
> ---
>  sysdeps/unix/sysv/linux/or1k/prctl.c | 42 ++++++++++++++++++++++++++++
>  1 file changed, 42 insertions(+)
>  create mode 100644 sysdeps/unix/sysv/linux/or1k/prctl.c
> 
> 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)