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
ReserveSpace(uint32_t offset,const CompiledMethod * compiled_method ATTRIBUTE_UNUSED,MethodReference method_ref ATTRIBUTE_UNUSED)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
ReserveSpaceEnd(uint32_t offset)31 uint32_t Mips64RelativePatcher::ReserveSpaceEnd(uint32_t offset) {
32 return offset; // No space reserved; no limit on relative call distance.
33 }
34
WriteThunks(OutputStream * out ATTRIBUTE_UNUSED,uint32_t offset)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
PatchCall(std::vector<uint8_t> * code,uint32_t literal_offset,uint32_t patch_offset,uint32_t target_offset)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
PatchPcRelativeReference(std::vector<uint8_t> * code,const LinkerPatch & patch,uint32_t patch_offset,uint32_t target_offset)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
PatchBakerReadBarrierBranch(std::vector<uint8_t> * code ATTRIBUTE_UNUSED,const LinkerPatch & patch ATTRIBUTE_UNUSED,uint32_t patch_offset ATTRIBUTE_UNUSED)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