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sortix--sortix/libc/x64/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
2.2 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/>.
x64/fork.S
Assembly functions related to forking x64 processes.
*******************************************************************************/
#define MSRID_FSBASE 0xC0000100
#define MSRID_GSBASE 0xC0000101
.section .text
.globl __sfork
.type __sfork, @function
__sfork:
pushq %rbp
movq %rsp, %rbp
pushq %rdi
pushq %rsi
movq $.Lafter_fork, (0 * 8)(%rsi) # rip
movq $0, (1 * 8)(%rsi) # rax, result is 0 for child
movq %rbx, (2 * 8)(%rsi)
movq %rcx, (3 * 8)(%rsi)
movq %rdx, (4 * 8)(%rsi)
movq %rdi, (5 * 8)(%rsi)
movq %rsi, (6 * 8)(%rsi)
movq %rsp, (7 * 8)(%rsi)
movq %rbp, (8 * 8)(%rsi)
movq %r8, (9 * 8)(%rsi)
movq %r9, (10 * 8)(%rsi)
movq %r10, (11 * 8)(%rsi)
movq %r11, (12 * 8)(%rsi)
movq %r12, (13 * 8)(%rsi)
movq %r13, (14 * 8)(%rsi)
movq %r14, (15 * 8)(%rsi)
movq %r15, (16 * 8)(%rsi)
pushfq
popq %rax
movq %rax, (17 * 8)(%rsi) # rflags
movl $MSRID_FSBASE, %edi
call rdmsr
movq 0(%rsp), %rsi
movq %rax, (18 * 8)(%rsi) # fsbase
movl $MSRID_GSBASE, %edi
call rdmsr
movq 0(%rsp), %rsi
movq %rax, (19 * 8)(%rsi) # gsbase
movq 8(%rsp), %rdi
call tfork
.Lafter_fork:
# The value in %rax determines whether we are child or parent. There is no
# need to clean up the stack from the above pushes, leaveq sets %rsp to %rbp
# which does that for us.
leaveq
retq
.size __sfork, . - __sfork