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/* Copyright (C) 2000-2020 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/>. */
#include <sysdep.h>
#include <asm/errno.h>
/* int __clone2(int (*fn) (void *arg), void *child_stack_base, */
/* size_t child_stack_size, int flags, void *arg, */
/* pid_t *parent_tid, void *tls, pid_t *child_tid) */
#define CHILD p8
#define PARENT p9
ENTRY(__clone2)
.prologue
alloc r2=ar.pfs,8,1,6,0
cmp.eq p6,p0=0,in0
cmp.eq p7,p0=0,in1
mov r8=EINVAL
mov out0=in3 /* Flags are first syscall argument. */
mov out1=in1 /* Stack address. */
(p6) br.cond.spnt.many __syscall_error /* no NULL function pointers */
(p7) br.cond.spnt.many __syscall_error /* no NULL stack pointers */
;;
mov out2=in2 /* Stack size. */
mov out3=in5 /* Parent TID Pointer */
mov out4=in7 /* Child TID Pointer */
mov out5=in6 /* TLS pointer */
/*
* clone2() is special: the child cannot execute br.ret right
* after the system call returns, because it starts out
* executing on an empty stack. Because of this, we can't use
* the new (lightweight) syscall convention here. Instead, we
* just fall back on always using "break".
*
* Furthermore, since the child starts with an empty stack, we
* need to avoid unwinding past invalid memory. To that end,
* we'll pretend now that __clone2() is the end of the
* call-chain. This is wrong for the parent, but only until
* it returns from clone2() but it's better than the
* alternative.
*/
mov r15=SYS_ify (clone2)
.save rp, r0
break __BREAK_SYSCALL
.body
cmp.eq p6,p0=-1,r10
cmp.eq CHILD,PARENT=0,r8 /* Are we the child? */
(p6) br.cond.spnt.many __syscall_error
;;
(CHILD) mov loc0=gp
(PARENT) ret
;;
ld8 out1=[in0],8 /* Retrieve code pointer. */
mov out0=in4 /* Pass proper argument to fn */
;;
ld8 gp=[in0] /* Load function gp. */
mov b6=out1
br.call.dptk.many rp=b6 /* Call fn(arg) in the child */
;;
mov out0=r8 /* Argument to exit */
mov gp=loc0
mov r15=SYS_ify (exit)
.save rp, r0
break __BREAK_SYSCALL
ret /* Not reached. */
PSEUDO_END(__clone2)
libc_hidden_def (__clone2)
/* For now we leave __clone undefined. This is unlikely to be a */
/* problem, since at least the i386 __clone in glibc always failed */
/* with a 0 sp (eventhough the kernel explicitly handled it). */
/* Thus all such calls needed to pass an explicit sp, and as a result, */
/* would be unlikely to work on ia64. */
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