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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 #ifndef ART_RUNTIME_ARCH_CONTEXT_H_
18 #define ART_RUNTIME_ARCH_CONTEXT_H_
19 
20 #include <stddef.h>
21 #include <stdint.h>
22 
23 #include "base/macros.h"
24 #include "base/mutex.h"
25 
26 namespace art {
27 
28 class QuickMethodFrameInfo;
29 
30 // Representation of a thread's context on the executing machine, used to implement long jumps in
31 // the quick stack frame layout.
32 class Context {
33  public:
34   // Creates a context for the running architecture
35   static Context* Create();
36 
~Context()37   virtual ~Context() {}
38 
39   // Re-initializes the registers for context re-use.
40   virtual void Reset() = 0;
41 
CalleeSaveAddress(uint8_t * frame,int num,size_t frame_size)42   static uintptr_t* CalleeSaveAddress(uint8_t* frame, int num, size_t frame_size) {
43     // Callee saves are held at the top of the frame
44     uint8_t* save_addr = frame + frame_size - ((num + 1) * sizeof(void*));
45 #if defined(__i386__) || defined(__x86_64__)
46     save_addr -= sizeof(void*);  // account for return address
47 #endif
48     return reinterpret_cast<uintptr_t*>(save_addr);
49   }
50 
51   // Reads values from callee saves in the given frame. The frame also holds
52   // the method that holds the layout.
53   virtual void FillCalleeSaves(uint8_t* frame, const QuickMethodFrameInfo& fr) = 0;
54 
55   // Sets the stack pointer value.
56   virtual void SetSP(uintptr_t new_sp) = 0;
57 
58   // Sets the program counter value.
59   virtual void SetPC(uintptr_t new_pc) = 0;
60 
61   // Sets the first argument register.
62   virtual void SetArg0(uintptr_t new_arg0_value) = 0;
63 
64   // Returns whether the given GPR is accessible (read or write).
65   virtual bool IsAccessibleGPR(uint32_t reg) = 0;
66 
67   // Gets the given GPRs address.
68   virtual uintptr_t* GetGPRAddress(uint32_t reg) = 0;
69 
70   // Reads the given GPR. The caller is responsible for checking the register
71   // is accessible with IsAccessibleGPR.
72   virtual uintptr_t GetGPR(uint32_t reg) = 0;
73 
74   // Sets the given GPR. The caller is responsible for checking the register
75   // is accessible with IsAccessibleGPR.
76   virtual void SetGPR(uint32_t reg, uintptr_t value) = 0;
77 
78   // Returns whether the given FPR is accessible (read or write).
79   virtual bool IsAccessibleFPR(uint32_t reg) = 0;
80 
81   // Reads the given FPR. The caller is responsible for checking the register
82   // is accessible with IsAccessibleFPR.
83   virtual uintptr_t GetFPR(uint32_t reg) = 0;
84 
85   // Sets the given FPR. The caller is responsible for checking the register
86   // is accessible with IsAccessibleFPR.
87   virtual void SetFPR(uint32_t reg, uintptr_t value) = 0;
88 
89   // Smashes the caller save registers. If we're throwing, we don't want to return bogus values.
90   virtual void SmashCallerSaves() = 0;
91 
92   // Switches execution of the executing context to this context
93   NO_RETURN virtual void DoLongJump() = 0;
94 
95  protected:
96   enum {
97     kBadGprBase = 0xebad6070,
98     kBadFprBase = 0xebad8070,
99   };
100 };
101 
102 }  // namespace art
103 
104 #endif  // ART_RUNTIME_ARCH_CONTEXT_H_
105