sysdeps/unix/sysv/linux/s390/s390-32/__makecontext_ret.S

   1 /* Copyright (C) 2012-2015 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <sysdep.h>
  19
  20 /* We do not want .eh_frame info so that __makecontext_ret stops unwinding
  21    if backtrace was called within a context created by makecontext. (There
  22    is also no .eh_frame info for _start or thread_start.)  */
  23 #undef cfi_startproc
  24 #define cfi_startproc
  25 #undef cfi_endproc
  26 #define cfi_endproc
  27
  28 ENTRY(__makecontext_ret)
  29         basr  %r14,%r7
  30         ltr   %r8,%r8                   /* Check whether uc_link is 0.  */
  31         jz    1f
  32         lr    %r2,%r8
  33         br    %r9
  34 1:      lhi   %r2,0                     /* EXIT return value.  */
  35         basr    %r13,0
  36 2:
  37 #ifdef PIC
  38         l       %r12,4f-2b(%r13)
  39         la      %r12,0(%r12,%r13)       /* GOT pointer in r12 after this.  */
  40         l       %r1,3f-2b(%r13)
  41         bas     %r14,0(%r1,%r12)
  42         .align  4
  43 3:
  44         .long   HIDDEN_JUMPTARGET (exit)@GOTOFF
  45 4:
  46         .long   _GLOBAL_OFFSET_TABLE_-2b
  47 #else
  48         l       %r1,3f-2b(%r13)
  49         basr    %r14,%r1
  50         .align  4
  51 3:
  52         .long   HIDDEN_JUMPTARGET (exit)
  53 #endif
  54         .align  2
  55         j       .+2                     /* Trap if exit returns for some reason.  */
  56 END(__makecontext_ret)