1/*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (C) 2023 Dmitry Chagin <dchagin@FreeBSD.org> 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28#include <machine/asm.h> 29 30 31 .text 32 .align 8 33 34 /* 35 * The program entry point 36 * %rdi %rsi 37 * void _start(char **ap, void (*cleanup)(void)) __dead2 38 */ 39 .globl _start 40 .type _start, @function 41_start: 42 .cfi_startproc 43 .cfi_undefined %rip /* Terminate call chain. */ 44 pushq %rbp /* Align stack, terminate call chain. */ 45 .cfi_def_cfa_offset 8 46 movq %rsp, %rbp 47 .cfi_offset %rbp, -16 48 .cfi_def_cfa_register %rbp 49#ifdef GCRT 50 subq $16, %rsp 51#endif 52 movq %rsi, %rcx 53 movq %rdi, %rsi /* argv = ap */ 54 addq $8, %rsi /* argv += 1 */ 55 movq %rdi, %rdx /* env = ap */ 56 addq $16, %rdx /* env += 2 */ 57 movslq (%rdi), %rax 58 movl %eax, %edi /* argc = *(long *)(void *)ap */ 59 shlq $3, %rax 60 addq %rax, %rdx /* env += argc */ 61#ifdef PIC 62 /* 63 * XXX. %rip relative addressing is not intended for use in the 64 * large memory model due to the offset from %rip being limited 65 * to 32 bits. 66 */ 67 leaq main@plt(%rip), %r8 68#else 69 movabsq $main, %r8 70#endif 71#ifdef GCRT 72 movabsq $eprol, %r9 73 movabsq $etext, %rax 74 movq %rax, (%rsp) 75 /* 76 * %edi %rsi %rdx %rcx %r8 %r9 (%rsp) 77 * __libc_start1_gcrt(argc, argv, env, cleanup, main, &eprol, &etext) 78 */ 79 callq __libc_start1_gcrt 80eprol: 81#else 82 /* __libc_start1(argc, argv, env, cleanup, main) */ 83 callq __libc_start1 84#endif 85 int3 86 .cfi_endproc 87 .size _start, . - _start 88 89 .section .note.GNU-stack,"",%progbits 90