sysdeps/i386/dl-trampoline.S

   1 /* PLT trampolines.  i386 version.
   2    Copyright (C) 2004-2017 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 #include <sysdep.h>
  20 #include <link-defines.h>
  21
  22 #ifdef HAVE_MPX_SUPPORT
  23 # define PRESERVE_BND_REGS_PREFIX bnd
  24 #else
  25 # define PRESERVE_BND_REGS_PREFIX .byte 0xf2
  26 #endif
  27
  28         .text
  29         .globl _dl_runtime_resolve
  30         .type _dl_runtime_resolve, @function
  31         cfi_startproc
  32         .align 16
  33 _dl_runtime_resolve:
  34         cfi_adjust_cfa_offset (8)
  35         pushl %eax              # Preserve registers otherwise clobbered.
  36         cfi_adjust_cfa_offset (4)
  37         pushl %ecx
  38         cfi_adjust_cfa_offset (4)
  39         pushl %edx
  40         cfi_adjust_cfa_offset (4)
  41         movl 16(%esp), %edx     # Copy args pushed by PLT in register.  Note
  42         movl 12(%esp), %eax     # that `fixup' takes its parameters in regs.
  43         call _dl_fixup          # Call resolver.
  44         popl %edx               # Get register content back.
  45         cfi_adjust_cfa_offset (-4)
  46         movl (%esp), %ecx
  47         movl %eax, (%esp)       # Store the function address.
  48         movl 4(%esp), %eax
  49         ret $12                 # Jump to function address.
  50         cfi_endproc
  51         .size _dl_runtime_resolve, .-_dl_runtime_resolve
  52
  53
  54 #ifndef PROF
  55         .globl _dl_runtime_profile
  56         .type _dl_runtime_profile, @function
  57         cfi_startproc
  58         .align 16
  59 _dl_runtime_profile:
  60         cfi_adjust_cfa_offset (8)
  61         pushl %esp
  62         cfi_adjust_cfa_offset (4)
  63         addl $8, (%esp)         # Account for the pushed PLT data
  64         pushl %ebp
  65         cfi_adjust_cfa_offset (4)
  66         pushl %eax              # Preserve registers otherwise clobbered.
  67         cfi_adjust_cfa_offset (4)
  68         pushl %ecx
  69         cfi_adjust_cfa_offset (4)
  70         pushl %edx
  71         cfi_adjust_cfa_offset (4)
  72         movl %esp, %ecx
  73         subl $8, %esp
  74         cfi_adjust_cfa_offset (8)
  75         movl $-1, 4(%esp)
  76         leal 4(%esp), %edx
  77         movl %edx, (%esp)
  78         pushl %ecx              # Address of the register structure
  79         cfi_adjust_cfa_offset (4)
  80         movl 40(%esp), %ecx     # Load return address
  81         movl 36(%esp), %edx     # Copy args pushed by PLT in register.  Note
  82         movl 32(%esp), %eax     # that `fixup' takes its parameters in regs.
  83         call _dl_profile_fixup  # Call resolver.
  84         cfi_adjust_cfa_offset (-8)
  85         movl (%esp), %edx
  86         testl %edx, %edx
  87         jns 1f
  88         popl %edx
  89         cfi_adjust_cfa_offset (-4)
  90         popl %edx               # Get register content back.
  91         cfi_adjust_cfa_offset (-4)
  92         movl (%esp), %ecx
  93         movl %eax, (%esp)       # Store the function address.
  94         movl 4(%esp), %eax
  95         ret $20                 # Jump to function address.
  96
  97         /*
  98             +32     return address
  99             +28     PLT1
 100             +24     PLT2
 101             +20     %esp
 102             +16     %ebp
 103             +12     %eax
 104             +8      %ecx
 105             +4      %edx
 106            %esp     free
 107         */
 108         cfi_adjust_cfa_offset (8)
 109 1:      movl %ebx, (%esp)
 110         cfi_rel_offset (ebx, 0)
 111         movl %edx, %ebx         # This is the frame buffer size
 112         pushl %edi
 113         cfi_adjust_cfa_offset (4)
 114         cfi_rel_offset (edi, 0)
 115         pushl %esi
 116         cfi_adjust_cfa_offset (4)
 117         cfi_rel_offset (esi, 0)
 118         leal 44(%esp), %esi
 119         movl %ebx, %ecx
 120         orl $4, %ebx            # Increase frame size if necessary to align
 121                                 # stack for the function call
 122         andl $~3, %ebx
 123         movl %esp, %edi
 124         subl %ebx, %edi
 125         movl %esp, %ebx
 126         cfi_def_cfa_register (ebx)
 127         movl %edi, %esp
 128         shrl $2, %ecx
 129         rep
 130         movsl
 131         movl (%ebx), %esi
 132         cfi_restore (esi)
 133         movl 4(%ebx), %edi
 134         cfi_restore (edi)
 135         /*
 136            %ebx+40  return address
 137            %ebx+36  PLT1
 138            %ebx+32  PLT2
 139            %ebx+28  %esp
 140            %ebx+24  %ebp
 141            %ebx+20  %eax
 142            %ebx+16  %ecx
 143            %ebx+12  %edx
 144            %ebx+8   %ebx
 145            %ebx+4   free
 146            %ebx     free
 147            %esp     copied stack frame
 148         */
 149         movl %eax, (%ebx)
 150         movl 12(%ebx), %edx
 151         movl 16(%ebx), %ecx
 152         movl 20(%ebx), %eax
 153         call *(%ebx)
 154         movl %ebx, %esp
 155         cfi_def_cfa_register (esp)
 156         movl 8(%esp), %ebx
 157         cfi_restore (ebx)
 158         /*
 159             +40     return address
 160             +36     PLT1
 161             +32     PLT2
 162             +28     %esp
 163             +24     %ebp
 164             +20     %eax
 165             +16     %ecx
 166             +12     %edx
 167             +8      free
 168             +4      free
 169            %esp     free
 170         */
 171 #if LONG_DOUBLE_SIZE != 12
 172 # error "long double size must be 12 bytes"
 173 #endif
 174         # Allocate space for La_i86_retval and subtract 12 free bytes.
 175         subl $(LRV_SIZE - 12), %esp
 176         cfi_adjust_cfa_offset (LRV_SIZE - 12)
 177         movl %eax, LRV_EAX_OFFSET(%esp)
 178         movl %edx, LRV_EDX_OFFSET(%esp)
 179         fstpt LRV_ST0_OFFSET(%esp)
 180         fstpt LRV_ST1_OFFSET(%esp)
 181 #ifdef HAVE_MPX_SUPPORT
 182         bndmov %bnd0, LRV_BND0_OFFSET(%esp)
 183         bndmov %bnd1, LRV_BND1_OFFSET(%esp)
 184 #else
 185         .byte 0x66,0x0f,0x1b,0x44,0x24,LRV_BND0_OFFSET
 186         .byte 0x66,0x0f,0x1b,0x4c,0x24,LRV_BND1_OFFSET
 187 #endif
 188         pushl %esp
 189         cfi_adjust_cfa_offset (4)
 190         # Address of La_i86_regs area.
 191         leal (LRV_SIZE + 4)(%esp), %ecx
 192         # PLT2
 193         movl (LRV_SIZE + 4 + LR_SIZE)(%esp), %eax
 194         # PLT1
 195         movl (LRV_SIZE + 4 + LR_SIZE + 4)(%esp), %edx
 196         call _dl_call_pltexit
 197         movl LRV_EAX_OFFSET(%esp), %eax
 198         movl LRV_EDX_OFFSET(%esp), %edx
 199         fldt LRV_ST1_OFFSET(%esp)
 200         fldt LRV_ST0_OFFSET(%esp)
 201 #ifdef HAVE_MPX_SUPPORT
 202         bndmov LRV_BND0_OFFSET(%esp), %bnd0
 203         bndmov LRV_BND1_OFFSET(%esp), %bnd1
 204 #else
 205         .byte 0x66,0x0f,0x1a,0x44,0x24,LRV_BND0_OFFSET
 206         .byte 0x66,0x0f,0x1a,0x4c,0x24,LRV_BND1_OFFSET
 207 #endif
 208         # Restore stack before return.
 209         addl $(LRV_SIZE + 4 + LR_SIZE + 4), %esp
 210         cfi_adjust_cfa_offset (-(LRV_SIZE + 4 + LR_SIZE + 4))
 211         PRESERVE_BND_REGS_PREFIX
 212         ret
 213         cfi_endproc
 214         .size _dl_runtime_profile, .-_dl_runtime_profile
 215 #endif