/*-
* 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.
*/
/*
* void execsp_start(struct ps_strings *ps_strings@arg0,
* void (*cleanup@arg1)(void), void *obj_main@arg2)
*
* ELF entry point. Saves the stack pointer in startsp and defers
* to the usual csu __start routine.
*/
LEAF_ENTRY(execsp_start)
/*
* Set up the data pointer (r19) and linkage table register
* (r27) like the real startup routine so we can get at the
* global symbols startsp and __start.
*
* XXX Not really sure why we need to set up r27, since we only
* use r19 here and the real startup routine, __start, will set
* up both r19 and r27 anyway. But this crashes with SIGSEGV
* shortly after startup if we don't set up r27, and gdb
* crashes on my attempts to single-step, so I'll just leave
* the initialization of r27 here for now until someone is
* motivated by the potential for a single-instruction
* micro-optimization in this test program to find out why r27
* is needed too.
*/
bl L$lpc, %r27
depi 0, 31, 2, %r27
L$lpc: addil L'_GLOBAL_OFFSET_TABLE_ - ($PIC_pcrel$0 - 8), %r27
ldo R'_GLOBAL_OFFSET_TABLE_ - ($PIC_pcrel$0 - 12)(%r1), %r27
copy %r27, %r19
/* Make execsp_ctor a constructor. */
.section .ctors,"aw",@progbits
.p2align 2
.word _C_LABEL(execsp_ctor)
/*
* int main(int argc@arg0, char **argv@arg1, ...)
*
* 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_ENTRY(main)
addil LT%_C_LABEL(mainsp), %r19 /* r1 := &mainsp */
ldw RT%_C_LABEL(mainsp)(%r1), %r1
stw %sp, 0(%r1) /* ctorsp := sp */
bv %r0(%rp) /* return... */
copy %r0, %ret0 /* ...zero */
EXIT(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_ENTRY(execsp_dtor)
addil LT%_C_LABEL(dtorsp), %r19 /* r20 := &dtorsp */
ldw RT%_C_LABEL(dtorsp)(%r1), %r20
/* PIC_TAILCALL(__start), if we had it */
addil LT%_C_LABEL(execsp_main), %r19 /* r1 := execsp_main */
ldw RT%_C_LABEL(execsp_main)(%r1), %r1
bv %r0(%r1) /* jump to execsp_main */
stw %sp, 0(%r20) /* startsp := sp */
EXIT(execsp_dtor)
/* Make execsp_ctor a destructor. */
.section .dtors,"aw",@progbits
.p2align 2
.word _C_LABEL(execsp_dtor)
