1  /* Test that lazy binding does not clobber r0.
       2     Copyright (C) 2018-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; if not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #include <assert.h>
      20  #include <dlfcn.h>
      21  #include <stdio.h>
      22  #include <stdlib.h>
      23  #include <unistd.h>
      24  
      25  #if defined (__s390x__)
      26  static const unsigned long magic_value = 0x0011223344556677UL;
      27  #else
      28  static const unsigned long magic_value = 0x00112233;
      29  #endif
      30  
      31  unsigned long r0x2_trampoline (unsigned long);
      32  
      33  /* Invoke r0x2, which doubles the value in r0.  If we get
      34     value * 2 back, this means nothing clobbers r0, particularly,
      35     _dl_runtime_resolve and _dl_runtime_profile.  */
      36  asm ("    .type r0x2_trampoline, @function\n"
      37       "r0x2_trampoline:\n"
      38  #if defined (__s390x__)
      39       "    lgr %r0,%r2\n"
      40       "    stg %r14,112(%r15)\n"
      41       "    aghi %r15,-160\n"
      42       "    brasl %r14,r0x2@plt\n"
      43       "    aghi %r15,160\n"
      44       "    lg %r14,112(%r15)\n"
      45       "    lgr %r2,%r0\n"
      46       "    br %r14\n"
      47  #elif defined (__zarch__)
      48       "    lr %r0,%r2\n"
      49       "    st %r14,56(%r15)\n"
      50       "    ahi %r15,-96\n"
      51       "    brasl %r14,r0x2@plt\n"
      52       "    ahi %r15,96\n"
      53       "    l %r14,56(%r15)\n"
      54       "    lr %r2,%r0\n"
      55       "    br %r14\n"
      56  #else
      57       "    lr %r0,%r2\n"
      58       "    st %r14,56(%r15)\n"
      59       "    ahi %r15,-96\n"
      60       "    balr %r14,0\n"
      61       "    l %r14,1f-.(%r14)\n"
      62       "    basr %r14,%r14\n"
      63       "    ahi %r15,96\n"
      64       "    l %r14,56(%r15)\n"
      65       "    lr %r2,%r0\n"
      66       "    br %r14\n"
      67       "1: .long r0x2\n"
      68  #endif
      69       );
      70  
      71  static int
      72  do_test (void)
      73  {
      74    int i;
      75    unsigned long r0;
      76    const char *run;
      77  
      78    for (i = 0; i < 2; i++)
      79      {
      80        run = (i == 0) ? "lazy" : "non-lazy";
      81        r0 = magic_value;
      82        printf ("-> %s r0 = 0x%lx\n", run, r0);
      83        r0 = r0x2_trampoline (r0);
      84        printf ("<- %s r0 * 2 = 0x%lx\n", run, r0);
      85        if (r0 != magic_value * 2)
      86  	return EXIT_FAILURE;
      87      }
      88    return EXIT_SUCCESS;
      89  }
      90  
      91  #include <support/test-driver.c>