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/* $NetBSD: execsp.S,v 1.2 2025/04/27 16:49:54 riastradh 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 1.2 2025/04/27 16:49:54 riastradh Exp $")
#include "SYS.h"
.text
/*
* void execsp_start(void *stackpointer@a0, void (*cleanup@a1)(void),
* void *obj_main@a2, struct ps_strings *ps_strings@a3)
*
* ELF entry point. Saves the stack pointer in startsp and defers
* to the usual csu __start routine.
*/
LEAF(execsp_start)
PIC_PROLOGUE(execsp_start) /* gp setup, sets t3 */
PTR_LA t1, _C_LABEL(startsp) /* load t1 := &startsp */
NOP_L /* load hazard */
PTR_S sp, 0(t1) /* store startsp := stack pointer */
PIC_TAILCALL(__start) /* gp restore, uses t3 */
END(execsp_start)
/*
* void execsp_ctor(void)
*
* ELF constructor. Saves the stack pointer in ctorsp and
* returns.
*/
LEAF(execsp_ctor)
PIC_PROLOGUE(execsp_ctor) /* gp setup, sets t3 */
PTR_LA t1, _C_LABEL(ctorsp) /* load t1 := &ctorsp */
NOP_L /* load hazard */
PTR_S sp, 0(t1) /* store ctorsp := stack pointer */
PIC_RETURN() /* gp restore, uses t3 */
END(execsp_ctor)
/* Make execsp_ctor a constructor. */
.pushsection .ctors,"aw",@progbits
.p2align PTR_SCALESHIFT
PTR_WORD _C_LABEL(execsp_ctor)
.popsection
/*
* int main(int argc@a0, char **argv@a1, ...)
*
* Main function. Saves the stack pointer in mainsp and returns
* zero. We will call execsp_main in execsp_dtor once dtorsp has
* been initialized.
*/
LEAF(main)
PIC_PROLOGUE(main) /* gp setup, sets t3 */
PTR_LA t1, _C_LABEL(mainsp) /* load t1 := &mainsp */
NOP_L /* load hazard */
PTR_S sp, 0(t1) /* store mainsp := stack pointer */
move v0, zero /* return 0 */
PIC_RETURN() /* gp restore, uses t3 */
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.
*/
LEAF(execsp_dtor)
PIC_PROLOGUE(execsp_dtor) /* gp setup, sets t3 */
PTR_LA t1, _C_LABEL(dtorsp) /* load t1 := &dtorsp */
NOP_L /* load hazard */
PTR_S sp, 0(t1) /* store dtorsp := stack pointer */
PIC_TAILCALL(execsp_main) /* gp restore, uses t3 */
END(execsp_dtor)
/* Make execsp_ctor a destructor. */
.pushsection .dtors,"aw",@progbits
.p2align PTR_SCALESHIFT
PTR_WORD _C_LABEL(execsp_dtor)
.popsection
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