Re: [PATCH v2 1/4] hurd: Simplify init-first.c further

[Samuel Thibault <samuel.thibault@gnu.org>]

Hello,

Thanks for this!

Did you try to run make check?

Sergey Bugaev via Libc-alpha, le mer. 22 févr. 2023 00:19:29 +0300, a ecrit:
> This drops all of the return address rewriting kludges. The only
> remaining hack is the jump out of a call stack while adjusting the
> stack pointer.

Is this hack really still needed? Since we don't switch stack any more,
we could as well just return normally?

> --- a/sysdeps/mach/hurd/dl-sysdep.c
> +++ b/sysdeps/mach/hurd/dl-sysdep.c
> @@ -207,6 +207,9 @@ _dl_sysdep_start (void **start_argptr,
>  	    }
>  	}
>  
> +      extern void _dl_init_first (void *data);

Please put extern function declaration into a header, dl-sysdep.h for
instance.

> diff --git a/sysdeps/mach/hurd/i386/init-first.c b/sysdeps/mach/hurd/i386/init-first.c
> index a558da16..34e8dcc0 100644
> --- a/sysdeps/mach/hurd/i386/init-first.c
> +++ b/sysdeps/mach/hurd/i386/init-first.c
> +  {
> +    /* Check if the stack we are now on is different from
> +       the one described by _hurd_stack_{base,size}.  */
>  
> +    char dummy;
> +    const vm_address_t newsp = (vm_address_t) &dummy;
> +
> +    if (d->stack_size != 0 && (newsp < d->stack_base
> +			       || newsp - d->stack_base > d->stack_size))
> +      /* The new stack pointer does not intersect with the
> +	 stack the exec server set up for us, so free that stack.  */
> +      __vm_deallocate (__mach_task_self (), d->stack_base, d->stack_size);
> +  }

Again, I don't think this is needed any more since we don't switch stack
any more?

Samuel