sysdeps/s390/s390-64/dl-trampoline.S

   1 /* PLT trampolines.  s390x version.
   2    Copyright (C) 2005-2014 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    <http://www.gnu.org/licenses/>.  */
  18
  19 /* The PLT stubs will call _dl_runtime_resolve/_dl_runtime_profile
  20  * with the following linkage:
  21  *   r2 - r6 : parameter registers
  22  *   f0, f2, f4, f6 : floating point parameter registers
  23  *   48(r15), 56(r15) : PLT arguments PLT1, PLT2
  24  *   160(r15) : additional stack parameters
  25  * The normal clobber rules for function calls apply:
  26  *   r0 - r5 : call clobbered
  27  *   r6 - r13 :  call saved
  28  *   r14 : return address (call clobbered)
  29  *   r15 : stack pointer (call saved)
  30  *   f1, f3, f5, f7 : call saved
  31  *   f0 - f3, f5, f7 - f15 : call clobbered
  32  */
  33
  34 #include <sysdep.h>
  35
  36         .text
  37         .globl _dl_runtime_resolve
  38         .type _dl_runtime_resolve, @function
  39         cfi_startproc
  40         .align 16
  41 _dl_runtime_resolve:
  42         stmg   %r2,%r5,64(15)   # save call-clobbered argument registers
  43         stg    %r14,96(15)
  44         cfi_offset (r14, -64)
  45         lgr    %r0,%r15
  46         aghi   %r15,-160        # create stack frame
  47         cfi_adjust_cfa_offset (160)
  48         stg    %r0,0(%r15)      # write backchain
  49         lmg    %r2,%r3,208(%r15)# load args saved by PLT
  50         brasl  %r14,_dl_fixup   # call fixup
  51         lgr    %r1,%r2          # function addr returned in r2
  52         aghi   %r15,160         # remove stack frame
  53         cfi_adjust_cfa_offset (-160)
  54         lg     %r14,96(15)      # restore registers
  55         lmg    %r2,%r5,64(15)
  56         br     %r1
  57         cfi_endproc
  58         .size _dl_runtime_resolve, .-_dl_runtime_resolve
  59
  60
  61 #ifndef PROF
  62         .globl _dl_runtime_profile
  63         .type _dl_runtime_profile, @function
  64         cfi_startproc
  65         .align 16
  66 _dl_runtime_profile:
  67         stmg   %r2,%r6,64(%r15)         # save call-clobbered arg regs
  68         std    %f0,104(%r15)            # + r6 needed as arg for
  69         std    %f2,112(%r15)            #  _dl_profile_fixup
  70         std    %f4,120(%r15)
  71         std    %f6,128(%r15)
  72         stg    %r12,24(%r15)            # r12 is used as backup of r15
  73         stg    %r14,32(%r15)
  74         cfi_offset (r6, -96)
  75         cfi_offset (f0, -56)
  76         cfi_offset (f2, -48)
  77         cfi_offset (f4, -40)
  78         cfi_offset (f6, -32)
  79         cfi_offset (r12, -136)
  80         cfi_offset (r14, -128)
  81         lgr    %r12,%r15                # backup stack pointer
  82         cfi_def_cfa_register (12)
  83         aghi   %r15,-160                # create stack frame
  84         stg    %r12,0(%r15)             # save backchain
  85         lmg    %r2,%r3,48(%r12)         # load arguments saved by PLT
  86         lgr    %r4,%r14                 # return address as third parameter
  87         la     %r5,64(%r12)             # pointer to struct La_s390_32_regs
  88         la     %r6,40(%r12)             # long int * framesize
  89         brasl  %r14,_dl_profile_fixup   # call resolver
  90         lgr    %r1,%r2                  # function addr returned in r2
  91         lg     %r0,40(%r12)             # load framesize
  92         ltgr   %r0,%r0
  93         jnm    1f
  94
  95         lmg    %r2,%r6,64(%r12)         # framesize < 0 means no pltexit call
  96         ld     %f0,104(%r12)            # so we can do a tail call without
  97         ld     %f2,112(%r12)            # copying the arg overflow area
  98         ld     %f4,120(%r12)
  99         ld     %f6,128(%r12)
 100
 101         lgr    %r15,%r12                # remove stack frame
 102         cfi_def_cfa_register (15)
 103         lg     %r14,32(%r15)            # restore registers
 104         lg     %r12,24(%r15)
 105         br     %r1                      # tail-call to resolved function
 106
 107         cfi_def_cfa_register (12)
 108 1:      jz     4f                       # framesize == 0 ?
 109         aghi   %r0,7                    # align framesize to 8
 110         nill   %r0,0xfff8
 111         slgr   %r15,%r0                 # make room for framesize bytes
 112         stg    %r12,0(%r15)
 113         la     %r2,160(%r15)
 114         la     %r3,160(%r12)
 115         srlg   %r0,%r0,3
 116 3:      mvc    0(8,%r2),0(%r3)          # copy additional parameters
 117         la     %r2,8(%r2)
 118         la     %r3,8(%r3)
 119         brctg  %r0,3b
 120 4:      lmg    %r2,%r6,64(%r12)         # load register parameters
 121         ld     %f0,104(%r12)            # restore call-clobbered arg regs
 122         ld     %f2,112(%r12)
 123         ld     %f4,120(%r12)
 124         ld     %f6,128(%r12)
 125         basr   %r14,%r1                 # call resolved function
 126         stg    %r2,136(%r12)
 127         std    %f0,144(%r12)
 128         lmg    %r2,%r3,48(%r12)         # load arguments saved by PLT
 129         la     %r4,32(%r12)             # pointer to struct La_s390_32_regs
 130         la     %r5,72(%r12)             # pointer to struct La_s390_32_retval
 131         brasl  %r14,_dl_call_pltexit
 132
 133         lgr    %r15,%r12                # remove stack frame
 134         cfi_def_cfa_register (15)
 135         lg     %r14,32(%r15)            # restore registers
 136         lg     %r12,24(%r15)
 137         br     %r14
 138
 139         cfi_endproc
 140         .size _dl_runtime_profile, .-_dl_runtime_profile
 141 #endif