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glibc/sysdeps/unix/sysv/linux/nios2/clone.S
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/* clone() implementation for Nios II. | |
Copyright (C) 2008-2016 Free Software Foundation, Inc. | |
This file is part of the GNU C Library. | |
Contributed by Andrew Jenner <andrew@codesourcery.com>, 2008. | |
The GNU 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 2.1 of the License, or (at your option) any later version. | |
The GNU 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 GNU C Library; if not, see | |
<http://www.gnu.org/licenses/>. */ | |
/* clone() is even more special than fork() as it mucks with stacks | |
and invokes a function in the right context after its all over. */ | |
#include <sysdep.h> | |
#define _ERRNO_H 1 | |
#include <bits/errno.h> | |
#include <tcb-offsets.h> | |
#define CLONE_VM 0x00000100 | |
#define CLONE_THREAD 0x00010000 | |
/* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg, | |
void *parent_tidptr, void *tls, void *child_tidptr) */ | |
.text | |
ENTRY(__clone) | |
/* Sanity check arguments. */ | |
movi r2, EINVAL | |
/* No NULL function pointers. */ | |
beq r4, zero, SYSCALL_ERROR_LABEL | |
/* No NULL stack pointers. */ | |
beq r5, zero, SYSCALL_ERROR_LABEL | |
subi r5, r5, 8 /* Reserve argument save space. */ | |
stw r4, 4(r5) /* Save function pointer. */ | |
stw r7, 0(r5) /* Save argument pointer. */ | |
/* Load arguments. */ | |
mov r4, r6 | |
ldw r6, 0(sp) | |
ldw r7, 8(sp) | |
ldw r8, 4(sp) | |
/* Do the system call. */ | |
movi r2, SYS_ify (clone) | |
/* End FDE now, because in the child the unwind info will be | |
wrong. */ | |
cfi_endproc | |
trap | |
/* Check for errors. */ | |
bne r7, zero, SYSCALL_ERROR_LABEL | |
/* See if we're on the newly created thread. */ | |
beq r2, zero, thread_start | |
/* Successful return from the parent */ | |
ret | |
thread_start: | |
cfi_startproc | |
cfi_undefined (ra) | |
/* We expect the argument registers to be preserved across system | |
calls and across task cloning, so flags should be in r4 here. */ | |
andhi r2, r4, %hi(CLONE_THREAD) | |
bne r2, zero, 2f | |
andi r3, r4, CLONE_VM | |
movi r2, -1 | |
bne r3, zero, 3f | |
DO_CALL (getpid, 0) | |
3: | |
stw r2, PID_OFFSET(r23) | |
stw r2, TID_OFFSET(r23) | |
2: | |
ldw r5, 4(sp) /* Function pointer. */ | |
ldw r4, 0(sp) /* Argument pointer. */ | |
addi sp, sp, 8 | |
/* Call the user's function. */ | |
callr r5 | |
/* _exit with the result. */ | |
mov r4, r2 | |
#ifdef PIC | |
nextpc r22 | |
1: movhi r8, %hiadj(_gp_got - 1b) | |
addi r8, r8, %lo(_gp_got - 1b) | |
add r22, r22, r8 | |
ldw r8, %call(HIDDEN_JUMPTARGET(_exit))(r22) | |
jmp r8 | |
#else | |
jmpi _exit | |
#endif | |
cfi_endproc | |
cfi_startproc | |
PSEUDO_END (__clone) | |
libc_hidden_def (__clone) | |
weak_alias (__clone, clone) |