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https://gitlab.com/sortix/sortix.git
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77 lines
2.1 KiB
ArmAsm
77 lines
2.1 KiB
ArmAsm
/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2012, 2014.
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This file is part of the Sortix C Library.
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The Sortix C Library is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation, either version 3 of the License, or (at your
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option) any later version.
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The Sortix C Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
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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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