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/* Copyright (C) 1996-2023 Free Software Foundation, Inc.
This file is part of the GNU C Library.
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
<https://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>
/* int clone(int (*fn)(void *arg), void *child_stack, int flags,
void *arg, pid_t *ptid, void *tls, pid_t *ctid);
Note that everything past ARG is technically optional, based
on FLAGS, and that CTID is arg 7, and thus is on the stack.
However, since a load from top-of-stack better be legal always,
we don't bother checking FLAGS. */
.text
.align 4
.globl __clone
.ent __clone
.usepv __clone, USEPV_PROF
cfi_startproc
__clone:
#ifdef PROF
.set noat
ldgp gp,0(pv)
lda AT, _mcount
jsr AT, (AT), _mcount
.set at
#endif
/* Sanity check arguments. */
ldiq v0, EINVAL
beq a0, SYSCALL_ERROR_LABEL /* no NULL function pointers */
beq a1, SYSCALL_ERROR_LABEL /* no NULL stack pointers */
/* Save the fn ptr and arg on the new stack. */
subq a1, 32, a1
stq a0, 0(a1)
stq a3, 8(a1)
stq a2, 16(a1)
/* The syscall is of the form clone(flags, usp, ptid, ctid, tls).
Shift the flags, ptid, ctid, tls arguments into place; the
child_stack argument is already correct. */
mov a2, a0
mov a4, a2
ldq a3, 0(sp)
mov a5, a4
/* Do the system call. */
ldiq v0, __NR_clone
call_pal PAL_callsys
bne a3, SYSCALL_ERROR_LABEL
beq v0, thread_start
/* Successful return from the parent. */
ret
PSEUDO_END(__clone)
cfi_endproc
/* Load up the arguments to the function. Put this block of code in
its own function so that we can terminate the stack trace with our
debug info. */
.align 4
.ent thread_start
cfi_startproc
thread_start:
mov 0, fp
cfi_def_cfa_register(fp)
cfi_undefined(ra)
/* Load up the arguments. */
ldq pv, 0(sp)
ldq a0, 8(sp)
addq sp, 32, sp
/* Call the user's function. */
jsr ra, (pv)
ldgp gp, 0(ra)
mov v0, a0
ldiq v0, __NR_exit
call_pal PAL_callsys
/* Die horribly. */
.align 4
halt
.align 4
cfi_endproc
.end thread_start
libc_hidden_def (__clone)
weak_alias (__clone, clone)
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