Re: [RFC v2 6/6] *-user: move safe-syscall.* to common-user

[Richard Henderson <richard.henderson@linaro.org>]

On 11/10/21 5:31 PM, Warner Losh wrote:
> Move linux-user/safe-syscall.S to common-user/common-safe-syscall.S and
> replace it with a #include "common-safe-syscall.S" so that bsd-user can
> also use it. Also move safe-syscall.h so that it can define a few more
> externs.
> 
> Signed-off-by: Warner Losh <imp@bsdimp.com>
> ---
>   common-user/common-safe-syscall.S          | 30 +++++++++++++++++++++
>   {linux-user => common-user}/safe-syscall.h |  0
>   linux-user/safe-syscall.S                  | 31 +---------------------
>   linux-user/signal.c                        |  1 +
>   meson.build                                |  1 +
>   5 files changed, 33 insertions(+), 30 deletions(-)
>   create mode 100644 common-user/common-safe-syscall.S
>   rename {linux-user => common-user}/safe-syscall.h (100%)
> 
> diff --git a/common-user/common-safe-syscall.S b/common-user/common-safe-syscall.S
> new file mode 100644
> index 0000000000..42ea7c40ba
> --- /dev/null
> +++ b/common-user/common-safe-syscall.S
> @@ -0,0 +1,30 @@
> +/*
> + * safe-syscall.S : include the host-specific assembly fragment
> + * to handle signals occurring at the same time as system calls.
> + *
> + * Written by Peter Maydell <peter.maydell@linaro.org>
> + *
> + * Copyright (C) 2016 Linaro Limited
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> + * See the COPYING file in the top-level directory.
> + */
> +
> +#include "hostdep.h"
> +#include "target_errno_defs.h"
> +
> +/* We have the correct host directory on our include path
> + * so that this will pull in the right fragment for the architecture.
> + */
> +#ifdef HAVE_SAFE_SYSCALL
> +#include "safe-syscall.inc.S"
> +#endif
> +
> +/* We must specifically say that we're happy for the stack to not be
> + * executable, otherwise the toolchain will default to assuming our
> + * assembly needs an executable stack and the whole QEMU binary will
> + * needlessly end up with one. This should be the last thing in this file.
> + */
> +#if defined(__linux__) && defined(__ELF__)
> +.section        .note.GNU-stack, "", %progbits
> +#endif

Hmm.  If we're going to split this file into safe-syscall.S and common-safe-syscall.S, we 
shouldn't do the ifdef thing here.  (Why it was present at all for linux-user is a mystery.)

What do you have planned for bsd-user that would be more than

> +#include "common-safe-syscall.S"

this?


r~