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104 lines
3.3 KiB
ArmAsm
104 lines
3.3 KiB
ArmAsm
/* Copyright (C) 2000-2014 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <sysdep.h>
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#include <asm/errno.h>
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/* int __clone2(int (*fn) (void *arg), void *child_stack_base, */
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/* size_t child_stack_size, int flags, void *arg, */
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/* pid_t *parent_tid, void *tls, pid_t *child_tid) */
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#define CHILD p8
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#define PARENT p9
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ENTRY(__clone2)
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.prologue
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alloc r2=ar.pfs,8,1,6,0
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cmp.eq p6,p0=0,in0
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cmp.eq p7,p0=0,in1
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mov r8=EINVAL
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mov out0=in3 /* Flags are first syscall argument. */
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mov out1=in1 /* Stack address. */
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(p6) br.cond.spnt.many __syscall_error /* no NULL function pointers */
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(p7) br.cond.spnt.many __syscall_error /* no NULL stack pointers */
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;;
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mov out2=in2 /* Stack size. */
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mov out3=in5 /* Parent TID Pointer */
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mov out4=in7 /* Child TID Pointer */
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mov out5=in6 /* TLS pointer */
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/*
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* clone2() is special: the child cannot execute br.ret right
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* after the system call returns, because it starts out
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* executing on an empty stack. Because of this, we can't use
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* the new (lightweight) syscall convention here. Instead, we
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* just fall back on always using "break".
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*
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* Furthermore, since the child starts with an empty stack, we
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* need to avoid unwinding past invalid memory. To that end,
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* we'll pretend now that __clone2() is the end of the
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* call-chain. This is wrong for the parent, but only until
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* it returns from clone2() but it's better than the
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* alternative.
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*/
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mov r15=SYS_ify (clone2)
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.save rp, r0
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break __BREAK_SYSCALL
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.body
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cmp.eq p6,p0=-1,r10
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cmp.eq CHILD,PARENT=0,r8 /* Are we the child? */
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(p6) br.cond.spnt.many __syscall_error
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;;
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(CHILD) mov loc0=gp
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(PARENT) ret
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;;
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tbit.nz p6,p0=in3,16 /* CLONE_THREAD */
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tbit.z p7,p10=in3,8 /* CLONE_VM */
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(p6) br.cond.dptk 1f
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;;
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mov r15=SYS_ify (getpid)
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(p10) addl r8=-1,r0
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(p7) break __BREAK_SYSCALL
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;;
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add r9=PID,r13
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add r10=TID,r13
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;;
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st4 [r9]=r8
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st4 [r10]=r8
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;;
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1: ld8 out1=[in0],8 /* Retrieve code pointer. */
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mov out0=in4 /* Pass proper argument to fn */
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;;
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ld8 gp=[in0] /* Load function gp. */
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mov b6=out1
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br.call.dptk.many rp=b6 /* Call fn(arg) in the child */
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;;
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mov out0=r8 /* Argument to _exit */
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mov gp=loc0
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.globl HIDDEN_JUMPTARGET(_exit)
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br.call.dpnt.many rp=HIDDEN_JUMPTARGET(_exit)
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/* call _exit with result from fn. */
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ret /* Not reached. */
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PSEUDO_END(__clone2)
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/* For now we leave __clone undefined. This is unlikely to be a */
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/* problem, since at least the i386 __clone in glibc always failed */
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/* with a 0 sp (eventhough the kernel explicitly handled it). */
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/* Thus all such calls needed to pass an explicit sp, and as a result, */
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/* would be unlikely to work on ia64. */
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