73 lines
1.9 KiB
ArmAsm
73 lines
1.9 KiB
ArmAsm
/*
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* Copyright (c) 2012, 2014 Jonas 'Sortie' Termansen.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* 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 WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* x86/fork.S
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* Assembly functions related to forking x86 processes.
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*/
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#define MSRID_FSBASE 0xC0000100
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#define MSRID_GSBASE 0xC0000101
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.section .text
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.globl __sfork
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.type __sfork, @function
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__sfork:
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pushl %ebp
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movl %esp, %ebp
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movl 12(%ebp), %ecx
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push %ecx
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movl 8(%ebp), %edx
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push %edx
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# -- stack is 16-byte aligned -- #
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movl $.Lafter_fork, (0 * 4)(%ecx) # eip
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movl $0, (1 * 4)(%ecx) # rax, result is 0 for child
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movl %ebx, (2 * 4)(%ecx)
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movl %ecx, (3 * 4)(%ecx)
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movl %edx, (4 * 4)(%ecx)
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movl %edi, (5 * 4)(%ecx)
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movl %esi, (6 * 4)(%ecx)
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movl %esp, (7 * 4)(%ecx)
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movl %ebp, (8 * 4)(%ecx)
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pushfl
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popl %eax
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movl %eax, (9 * 4)(%ecx) # eflags
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subl $12, %esp
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pushl $MSRID_FSBASE
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call rdmsr
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movl 12(%ebp), %ecx
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movl %eax, (10 * 4)(%ecx) # fsbase
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addl $16, %esp
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subl $12, %esp
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pushl $MSRID_GSBASE
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call rdmsr
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movl 12(%ebp), %ecx
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movl %eax, (11 * 4)(%ecx) # gsbase
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addl $16, %esp
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call tfork
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.Lafter_fork:
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# The value in %eax: determines whether we are child or parent. There is no
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# need to clean up the stack from the above pushes, leavel sets %esp to %ebp
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# which does that for us.
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leavel
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retl
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.size __sfork, . - __sfork
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