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sortix--sortix/libc/x86/fork.S
Jonas 'Sortie' Termansen 30cd318c17 Implement signals.
Note: This is an incompatible ABI change.
2014-07-22 13:25:39 +02:00

77 lines
2.1 KiB
ArmAsm

/*******************************************************************************
Copyright(C) Jonas 'Sortie' Termansen 2012, 2014.
This file is part of the Sortix C Library.
The Sortix C Library is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 3 of the License, or (at your
option) any later version.
The Sortix C Library is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
License for more details.
You should have received a copy of the GNU Lesser General Public License
along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
x86/fork.S
Assembly functions related to forking x86 processes.
*******************************************************************************/
#define MSRID_FSBASE 0xC0000100
#define MSRID_GSBASE 0xC0000101
.section .text
.globl __sfork
.type __sfork, @function
__sfork:
pushl %ebp
movl %esp, %ebp
movl 12(%ebp), %ecx
push %ecx
movl 8(%ebp), %edx
push %edx
# -- stack is 16-byte aligned -- #
movl $.Lafter_fork, (0 * 4)(%ecx) # eip
movl $0, (1 * 4)(%ecx) # rax, result is 0 for child
movl %ebx, (2 * 4)(%ecx)
movl %ecx, (3 * 4)(%ecx)
movl %edx, (4 * 4)(%ecx)
movl %edi, (5 * 4)(%ecx)
movl %esi, (6 * 4)(%ecx)
movl %esp, (7 * 4)(%ecx)
movl %ebp, (8 * 4)(%ecx)
pushfl
popl %eax
movl %eax, (9 * 4)(%ecx) # eflags
subl $12, %esp
pushl $MSRID_FSBASE
call rdmsr
movl 12(%ebp), %ecx
movl %eax, (10 * 4)(%ecx) # fsbase
addl $16, %esp
subl $12, %esp
pushl $MSRID_GSBASE
call rdmsr
movl 12(%ebp), %ecx
movl %eax, (11 * 4)(%ecx) # gsbase
addl $16, %esp
call tfork
.Lafter_fork:
# The value in %eax: determines whether we are child or parent. There is no
# need to clean up the stack from the above pushes, leavel sets %esp to %ebp
# which does that for us.
leavel
retl
.size __sfork, . - __sfork