mirror of
https://github.com/jart/cosmopolitan.git
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3d172c99fe
This version has better error messages and safety checks. It supports loading static position-independent executables. It correctly handles more kinds of weird ELF program header layouts. A force flag has been added to avoid system execve(). Finally the longstanding misalignment with our ELF PT_NOTE section has been addressed.
53 lines
2.8 KiB
ArmAsm
53 lines
2.8 KiB
ArmAsm
/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8 -*-│
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│vi: set et ft=asm ts=8 tw=8 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2023 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/macros.internal.h"
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// Calls _start() function of loaded program.
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//
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// When the program entrypoint is called, all registers shall be
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// cleared, with the exception of (1) %rdi will be equal to %rsp
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// on FreeBSD and (2) %cl will contain the detected host OS code
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//
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// We clear all the general registers we can to have some wiggle
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// room, to extend the behavior of this loader in the future. We
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// don't need to clear the XMM registers because your APE loader
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// should be compiled using gcc/clang's -mgeneral-regs-only flag
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//
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// @param rdi is passed through as-is
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// @param rsi is address of entrypoint (becomes zero)
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// @param rdx is stack pointer (becomes zero)
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// @param rcx is passed through as-is
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// @noreturn
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Launch: xor %r8d,%r8d
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xor %r9d,%r9d
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xor %r10d,%r10d
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xor %r11d,%r11d
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xor %r12d,%r12d
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xor %r13d,%r13d
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xor %r14d,%r14d
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xor %r15d,%r15d
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mov %rdx,%rsp
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xor %edx,%edx
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push %rsi
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xor %esi,%esi
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xor %ebp,%ebp
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xor %ebx,%ebx
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xor %eax,%eax
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ret
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.endfn Launch,globl
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