1 /*
   2  * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 
  25 
  26 package jdk.tools.jaotc.binformat.elf;
  27 
  28 import jdk.tools.jaotc.binformat.BinaryContainer;
  29 import jdk.tools.jaotc.binformat.Relocation;
  30 import jdk.tools.jaotc.binformat.Relocation.RelocType;
  31 import jdk.tools.jaotc.binformat.Symbol;
  32 import jdk.tools.jaotc.binformat.elf.Elf.Elf64_Ehdr;
  33 import jdk.tools.jaotc.binformat.elf.Elf.Elf64_Rela;
  34 
  35 public class AMD64JELFRelocObject extends JELFRelocObject {
  36 
  37     AMD64JELFRelocObject(BinaryContainer binContainer, String outputFileName) {
  38         super(binContainer, outputFileName);
  39     }
  40 
  41     @Override
  42     protected void createRelocation(Symbol symbol, Relocation reloc, ElfRelocTable elfRelocTable) {
  43         RelocType relocType = reloc.getType();
  44 
  45         int elfRelocType = getELFRelocationType(relocType);
  46         ElfSymbol sym = (ElfSymbol) symbol.getNativeSymbol();
  47         int symno = sym.getIndex();
  48         int sectindex = reloc.getSection().getSectionId();
  49         int offset = reloc.getOffset();
  50         int addend = 0;
  51 
  52         switch (relocType) {
  53             case JAVA_CALL_DIRECT:
  54             case STUB_CALL_DIRECT:
  55             case FOREIGN_CALL_INDIRECT_GOT: {
  56                 // Create relocation entry
  57                 addend = -4; // Size in bytes of the patch location
  58                 // Relocation should be applied at the location after call operand
  59                 offset = offset + reloc.getSize() + addend;
  60                 break;
  61             }
  62             case JAVA_CALL_INDIRECT:
  63             case METASPACE_GOT_REFERENCE:
  64             case EXTERNAL_PLT_TO_GOT: {
  65                 addend = -4; // Size of 32-bit address of the GOT
  66                 /*
  67                  * Relocation should be applied before the test instruction to the move instruction.
  68                  * reloc.getOffset() points to the test instruction after the instruction that loads
  69                  * the address of polling page. So set the offset appropriately.
  70                  */
  71                 offset = offset + addend;
  72                 break;
  73             }
  74             case EXTERNAL_GOT_TO_PLT: {
  75                 // this is load time relocations
  76                 break;
  77             }
  78             default:
  79                 throw new InternalError("Unhandled relocation type: " + relocType);
  80         }
  81         elfRelocTable.createRelocationEntry(sectindex, offset, symno, elfRelocType, addend);
  82     }
  83 
  84     private static int getELFRelocationType(RelocType relocType) {
  85         int elfRelocType = 0; // R_<ARCH>_NONE if #define'd to 0 for all values of ARCH
  86         switch (ElfTargetInfo.getElfArch()) {
  87             case Elf64_Ehdr.EM_X86_64:
  88                 // Return R_X86_64_* entries based on relocType
  89                 if (relocType == RelocType.JAVA_CALL_DIRECT ||
  90                                 relocType == RelocType.FOREIGN_CALL_INDIRECT_GOT) {
  91                     elfRelocType = Elf64_Rela.R_X86_64_PLT32;
  92                 } else if (relocType == RelocType.STUB_CALL_DIRECT) {
  93                     elfRelocType = Elf64_Rela.R_X86_64_PC32;
  94                 } else if (relocType == RelocType.JAVA_CALL_INDIRECT) {
  95                     elfRelocType = Elf64_Rela.R_X86_64_NONE;
  96                 } else if (relocType == RelocType.METASPACE_GOT_REFERENCE ||
  97                                 relocType == RelocType.EXTERNAL_PLT_TO_GOT) {
  98                     elfRelocType = Elf64_Rela.R_X86_64_PC32;
  99                 } else if (relocType == RelocType.EXTERNAL_GOT_TO_PLT) {
 100                     elfRelocType = Elf64_Rela.R_X86_64_64;
 101                 } else {
 102                     assert false : "Unhandled relocation type: " + relocType;
 103                 }
 104                 break;
 105 
 106             default:
 107                 System.out.println("Relocation Type mapping: Unhandled architecture: " + ElfTargetInfo.getElfArch());
 108         }
 109         return elfRelocType;
 110     }
 111 }