/*      $NetBSD: execsp.S,v 1.3 2025/06/04 19:25:45 christos Exp $      */

/*-
* Copyright (c) 2025 The NetBSD Foundation, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/

#define _LOCORE

#include <machine/asm.h>

RCSID("$NetBSD: execsp.S,v 1.3 2025/06/04 19:25:45 christos Exp $")

/*
* void execsp_start(void (*cleanup@x0)(void), void *obj_main@x1,
*     struct ps_strings *ps_strings@x2)
*
*      ELF entry point.  Saves the stack pointer in startsp and defers
*      to the usual csu __start routine.
*/
ENTRY(execsp_start)
       mov     x16, sp
       adrp    x17, _C_LABEL(startsp)
       str     x16, [x17, :lo12:_C_LABEL(startsp)]
       b       _C_LABEL(__start)
END(execsp_start)

/*
* void execsp_ctor(void)
*
*      ELF constructor.  Saves the stack pointer in ctorsp and
*      returns.
*/
ENTRY(execsp_ctor)
       mov     x16, sp
       adrp    x17, _C_LABEL(ctorsp)
       str     x16, [x17, :lo12:_C_LABEL(ctorsp)]
       ret
END(execsp_ctor)

       /* Make execsp_ctor a constructor. */
       .section .init_array,"aw",%init_array
       .p2align 3
       .xword  _C_LABEL(execsp_ctor)

/*
* int main(int argc@x0, char **argv@x1, ...)
*
*      Main function.  Saves the stack pointer in mainsp and returns
*      zero.  We will call execsp_main in execsp_dtor once dtorsp has
*      been initialized.
*/
ENTRY(main)
       mov     x16, sp
       adrp    x17, _C_LABEL(mainsp)
       str     x16, [x17, :lo12:_C_LABEL(mainsp)]
       mov     x0, #0
       ret
END(main)

/*
* void execsp_dtor(void)
*
*      ELF destructor.  Saves the stack pointer in dtorsp and defers
*      to the C execsp_main in h_execsp.c to report the stack pointers
*      back to the t_signal_and_sp parent.
*/
ENTRY(execsp_dtor)
       mov     x16, sp
       adrp    x17, _C_LABEL(dtorsp)
       str     x16, [x17, :lo12:_C_LABEL(dtorsp)]
       b       _C_LABEL(execsp_main)
END(execsp_dtor)

       /* Make execsp_ctor a destructor. */
       .section .fini_array,"aw",%fini_array
       .p2align 3
       .xword  _C_LABEL(execsp_dtor)