/*-
* 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(void (*cleanup@rbx)(void), void *obj_main@rcx,
* struct ps_strings *ps_strings@rbx)
*
* ELF entry point. Saves the stack pointer in startsp and defers
* to the usual csu __start routine.
*/
ENTRY(execsp_start)
movq %rsp,_C_LABEL(startsp)(%rip)
/*
* No adjustment like in main because entry point is special
* and the amd64 csu __start routine takes care of it.
*
* XXX Why don't we just arrange to align it in the kernel
* anyway?
*/
jmp _C_LABEL(__start)
END(execsp_start)
/*
* void execsp_ctor(void)
*
* ELF constructor. Saves the stack pointer in ctorsp and
* returns.
*/
ENTRY(execsp_ctor)
/*
* `The end of the input argument area shall be aligned on a
* [16-byte] boundary. In other words, the value of (%rsp + 8)
* is always a multiple of 16 when control is transferred to
* the function entry point.'
*
* To make it convenient for t_signal_and_sp.c, we subtract 8
* from %rsp in order to get something congruent to zero modulo
* the stack alignemnt.
*/
movq %rsp,_C_LABEL(ctorsp)(%rip)
addq $-8,_C_LABEL(ctorsp)(%rip)
ret
END(execsp_ctor)
/* Make execsp_ctor a constructor. */
.section .ctors,"aw",@progbits
.p2align 3
.quad _C_LABEL(execsp_ctor)
/*
* int main(int argc@rdi, char **argv@rsi, ...)
*
* 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)
movq %rsp,_C_LABEL(mainsp)(%rip)
addq $-8,_C_LABEL(mainsp)(%rip)
xorl %eax,%eax
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)
movq %rsp,_C_LABEL(dtorsp)(%rip)
addq $-8,_C_LABEL(dtorsp)(%rip)
jmp _C_LABEL(execsp_main)
END(execsp_dtor)
/* Make execsp_ctor a destructor. */
.section .dtors,"aw",@progbits
.p2align 3
.quad _C_LABEL(execsp_dtor)
