1 /* 2 * Copyright (C) 2016 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include "linker/mips64/relative_patcher_mips64.h" 18 19 #include "compiled_method.h" 20 21 namespace art { 22 namespace linker { 23 24 uint32_t Mips64RelativePatcher::ReserveSpace( 25 uint32_t offset, 26 const CompiledMethod* compiled_method ATTRIBUTE_UNUSED, 27 MethodReference method_ref ATTRIBUTE_UNUSED) { 28 return offset; // No space reserved; no limit on relative call distance. 29 } 30 31 uint32_t Mips64RelativePatcher::ReserveSpaceEnd(uint32_t offset) { 32 return offset; // No space reserved; no limit on relative call distance. 33 } 34 35 uint32_t Mips64RelativePatcher::WriteThunks(OutputStream* out ATTRIBUTE_UNUSED, uint32_t offset) { 36 return offset; // No thunks added; no limit on relative call distance. 37 } 38 39 void Mips64RelativePatcher::PatchCall(std::vector<uint8_t>* code, 40 uint32_t literal_offset, 41 uint32_t patch_offset, 42 uint32_t target_offset) { 43 // Basic sanity checks. 44 DCHECK_GE(code->size(), 8u); 45 DCHECK_LE(literal_offset, code->size() - 8u); 46 // auipc reg, offset_high 47 DCHECK_EQ((*code)[literal_offset + 0], 0x34); 48 DCHECK_EQ((*code)[literal_offset + 1], 0x12); 49 DCHECK_EQ(((*code)[literal_offset + 2] & 0x1F), 0x1E); 50 DCHECK_EQ(((*code)[literal_offset + 3] & 0xFC), 0xEC); 51 // jialc reg, offset_low 52 DCHECK_EQ((*code)[literal_offset + 4], 0x78); 53 DCHECK_EQ((*code)[literal_offset + 5], 0x56); 54 DCHECK_EQ(((*code)[literal_offset + 6] & 0xE0), 0x00); 55 DCHECK_EQ((*code)[literal_offset + 7], 0xF8); 56 57 // Apply patch. 58 uint32_t diff = target_offset - patch_offset; 59 // Note that a combination of auipc with an instruction that adds a sign-extended 60 // 16-bit immediate operand (e.g. jialc) provides a PC-relative range of 61 // PC-0x80000000 to PC+0x7FFF7FFF on MIPS64, that is, short of 2GB on one end 62 // by 32KB. 63 diff += (diff & 0x8000) << 1; // Account for sign extension in jialc. 64 65 // auipc reg, offset_high 66 (*code)[literal_offset + 0] = static_cast<uint8_t>(diff >> 16); 67 (*code)[literal_offset + 1] = static_cast<uint8_t>(diff >> 24); 68 // jialc reg, offset_low 69 (*code)[literal_offset + 4] = static_cast<uint8_t>(diff >> 0); 70 (*code)[literal_offset + 5] = static_cast<uint8_t>(diff >> 8); 71 } 72 73 void Mips64RelativePatcher::PatchPcRelativeReference(std::vector<uint8_t>* code, 74 const LinkerPatch& patch, 75 uint32_t patch_offset, 76 uint32_t target_offset) { 77 uint32_t anchor_literal_offset = patch.PcInsnOffset(); 78 uint32_t literal_offset = patch.LiteralOffset(); 79 80 // Basic sanity checks. 81 DCHECK_GE(code->size(), 8u); 82 DCHECK_LE(literal_offset, code->size() - 8u); 83 DCHECK_EQ(literal_offset, anchor_literal_offset); 84 // auipc reg, offset_high 85 DCHECK_EQ((*code)[literal_offset + 0], 0x34); 86 DCHECK_EQ((*code)[literal_offset + 1], 0x12); 87 DCHECK_EQ(((*code)[literal_offset + 2] & 0x1F), 0x1E); 88 DCHECK_EQ(((*code)[literal_offset + 3] & 0xFC), 0xEC); 89 // instr reg(s), offset_low 90 DCHECK_EQ((*code)[literal_offset + 4], 0x78); 91 DCHECK_EQ((*code)[literal_offset + 5], 0x56); 92 93 // Apply patch. 94 uint32_t anchor_offset = patch_offset - literal_offset + anchor_literal_offset; 95 uint32_t diff = target_offset - anchor_offset; 96 // Note that a combination of auipc with an instruction that adds a sign-extended 97 // 16-bit immediate operand (e.g. ld) provides a PC-relative range of 98 // PC-0x80000000 to PC+0x7FFF7FFF on MIPS64, that is, short of 2GB on one end 99 // by 32KB. 100 diff += (diff & 0x8000) << 1; // Account for sign extension in instruction following auipc. 101 102 // auipc reg, offset_high 103 (*code)[literal_offset + 0] = static_cast<uint8_t>(diff >> 16); 104 (*code)[literal_offset + 1] = static_cast<uint8_t>(diff >> 24); 105 // instr reg(s), offset_low 106 (*code)[literal_offset + 4] = static_cast<uint8_t>(diff >> 0); 107 (*code)[literal_offset + 5] = static_cast<uint8_t>(diff >> 8); 108 } 109 110 void Mips64RelativePatcher::PatchBakerReadBarrierBranch(std::vector<uint8_t>* code ATTRIBUTE_UNUSED, 111 const LinkerPatch& patch ATTRIBUTE_UNUSED, 112 uint32_t patch_offset ATTRIBUTE_UNUSED) { 113 LOG(FATAL) << "UNIMPLEMENTED"; 114 } 115 116 } // namespace linker 117 } // namespace art 118
