1 /*
2 * Copyright (C) 2011 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 "context_arm.h"
18
19 #include "base/bit_utils.h"
20 #include "base/bit_utils_iterator.h"
21 #include "quick/quick_method_frame_info.h"
22 #include "thread-current-inl.h"
23
24 namespace art {
25 namespace arm {
26
27 static constexpr uint32_t gZero = 0;
28
Reset()29 void ArmContext::Reset() {
30 std::fill_n(gprs_, arraysize(gprs_), nullptr);
31 std::fill_n(fprs_, arraysize(fprs_), nullptr);
32 gprs_[SP] = &sp_;
33 gprs_[PC] = &pc_;
34 gprs_[R0] = &arg0_;
35 // Initialize registers with easy to spot debug values.
36 sp_ = ArmContext::kBadGprBase + SP;
37 pc_ = ArmContext::kBadGprBase + PC;
38 arg0_ = 0;
39 }
40
FillCalleeSaves(uint8_t * frame,const QuickMethodFrameInfo & frame_info)41 void ArmContext::FillCalleeSaves(uint8_t* frame, const QuickMethodFrameInfo& frame_info) {
42 int spill_pos = 0;
43
44 // Core registers come first, from the highest down to the lowest.
45 uint32_t core_regs = frame_info.CoreSpillMask();
46 DCHECK_EQ(0u, core_regs & (static_cast<uint32_t>(-1) << kNumberOfCoreRegisters));
47 for (uint32_t core_reg : HighToLowBits(core_regs)) {
48 gprs_[core_reg] = CalleeSaveAddress(frame, spill_pos, frame_info.FrameSizeInBytes());
49 ++spill_pos;
50 }
51 DCHECK_EQ(spill_pos, POPCOUNT(frame_info.CoreSpillMask()));
52
53 // FP registers come second, from the highest down to the lowest.
54 for (uint32_t fp_reg : HighToLowBits(frame_info.FpSpillMask())) {
55 fprs_[fp_reg] = CalleeSaveAddress(frame, spill_pos, frame_info.FrameSizeInBytes());
56 ++spill_pos;
57 }
58 DCHECK_EQ(spill_pos, POPCOUNT(frame_info.CoreSpillMask()) + POPCOUNT(frame_info.FpSpillMask()));
59 }
60
SetGPR(uint32_t reg,uintptr_t value)61 void ArmContext::SetGPR(uint32_t reg, uintptr_t value) {
62 DCHECK_LT(reg, static_cast<uint32_t>(kNumberOfCoreRegisters));
63 DCHECK(IsAccessibleGPR(reg));
64 DCHECK_NE(gprs_[reg], &gZero); // Can't overwrite this static value since they are never reset.
65 *gprs_[reg] = value;
66 }
67
SetFPR(uint32_t reg,uintptr_t value)68 void ArmContext::SetFPR(uint32_t reg, uintptr_t value) {
69 DCHECK_LT(reg, static_cast<uint32_t>(kNumberOfSRegisters));
70 DCHECK(IsAccessibleFPR(reg));
71 DCHECK_NE(fprs_[reg], &gZero); // Can't overwrite this static value since they are never reset.
72 *fprs_[reg] = value;
73 }
74
SmashCallerSaves()75 void ArmContext::SmashCallerSaves() {
76 // This needs to be 0 because we want a null/zero return value.
77 gprs_[R0] = const_cast<uint32_t*>(&gZero);
78 gprs_[R1] = const_cast<uint32_t*>(&gZero);
79 gprs_[R2] = nullptr;
80 gprs_[R3] = nullptr;
81
82 fprs_[S0] = nullptr;
83 fprs_[S1] = nullptr;
84 fprs_[S2] = nullptr;
85 fprs_[S3] = nullptr;
86 fprs_[S4] = nullptr;
87 fprs_[S5] = nullptr;
88 fprs_[S6] = nullptr;
89 fprs_[S7] = nullptr;
90 fprs_[S8] = nullptr;
91 fprs_[S9] = nullptr;
92 fprs_[S10] = nullptr;
93 fprs_[S11] = nullptr;
94 fprs_[S12] = nullptr;
95 fprs_[S13] = nullptr;
96 fprs_[S14] = nullptr;
97 fprs_[S15] = nullptr;
98 }
99
100 extern "C" NO_RETURN void art_quick_do_long_jump(uint32_t*, uint32_t*);
101
DoLongJump()102 void ArmContext::DoLongJump() {
103 uintptr_t gprs[kNumberOfCoreRegisters];
104 uint32_t fprs[kNumberOfSRegisters];
105 for (size_t i = 0; i < kNumberOfCoreRegisters; ++i) {
106 gprs[i] = gprs_[i] != nullptr ? *gprs_[i] : ArmContext::kBadGprBase + i;
107 }
108 for (size_t i = 0; i < kNumberOfSRegisters; ++i) {
109 fprs[i] = fprs_[i] != nullptr ? *fprs_[i] : ArmContext::kBadFprBase + i;
110 }
111 // Ensure the Thread Register contains the address of the current thread.
112 DCHECK_EQ(reinterpret_cast<uintptr_t>(Thread::Current()), gprs[TR]);
113 // The Marking Register will be updated by art_quick_do_long_jump.
114 art_quick_do_long_jump(gprs, fprs);
115 }
116
117 } // namespace arm
118 } // namespace art
119