sysdeps/unix/sysv/linux/hppa/clone.S

   1 /* Copyright (C) 1996, 1997, 2000 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by David Huggins-Daines <dhd@debian.org>, 2000.
   4    Based on the Alpha version by Richard Henderson <rth@tamu.edu>, 1996.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 /* clone() is even more special than fork() as it mucks with stacks
  22    and invokes a function in the right context after its all over.  */
  23
  24 #include <asm/unistd.h>
  25 #include <sysdep.h>
  26 #define _ERRNO_H        1
  27 #include <bits/errno.h>
  28
  29 /* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg) */
  30
  31         .text
  32 ENTRY(__clone)
  33         /* FIXME: I have no idea how profiling works on hppa. */
  34
  35         /* Sanity check arguments.  */
  36         comib,=  0,%arg0,.Lerror        /* no NULL function pointers */
  37         ldi     -EINVAL,%ret0
  38         comib,=  0,%arg1,.Lerror        /* no NULL stack pointers */
  39         nop
  40
  41         /* Save the fn ptr and arg on the new stack.  */
  42         stwm    %arg0,64(%arg1)
  43         stw     %arg3,-60(%arg1)
  44
  45         /* Save the PIC register. */
  46 #ifdef PIC
  47         stw     %r19,-32(%sr0, %sp)     /* parent */
  48 #endif
  49
  50         /* Do the system call */
  51         copy    %arg2,%arg0
  52         ble     0x100(%sr2,%r0)
  53         ldi     __NR_clone,%r20
  54
  55         ldi     -4096,%r1
  56         comclr,>>= %r1,%ret0,%r0        /* Note: unsigned compare. */
  57         b,n     .Lerror
  58
  59         comib,=,n 0,%ret0,thread_start
  60
  61         /* Successful return from the parent
  62            No need to restore the PIC register,
  63            since we return immediately. */
  64
  65         bv      %r0(%rp)
  66         nop
  67
  68         /* Something bad happened -- no child created */
  69 .Lerror:
  70
  71         /* Restore the PIC register on error */
  72 #ifdef PIC
  73         ldw     -32(%sr0, %sp), %r19    /* parent */
  74 #endif
  75
  76         b       __syscall_error
  77         sub     %r0,%ret0,%arg0
  78
  79 thread_start:
  80
  81         /* Load up the arguments.  */
  82         ldw     -60(%sr0, %sp),%arg0
  83         ldw     -64(%sr0, %sp),%r22
  84
  85         /* $$dyncall fixes childs PIC register */
  86
  87         /* Call the user's function */
  88         bl      $$dyncall,%r31
  89         copy    %r31,%rp
  90
  91         bl      _exit,%rp
  92         copy    %ret0,%arg0
  93
  94         /* Die horribly.  */
  95         iitlbp  %r0,(%r0)
  96
  97 PSEUDO_END(__clone)
  98
  99 weak_alias(__clone, clone)