1  // -*- mode: C++ -*-
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 30  
 31  // stackwalker_arm64.h: arm64-specific stackwalker.
 32  //
 33  // Provides stack frames given arm64 register context and a memory region
 34  // corresponding to an arm64 stack.
 35  //
 36  // Author: Mark Mentovai, Ted Mielczarek, Colin Blundell
 37  
 38  
 39  #ifndef PROCESSOR_STACKWALKER_ARM64_H__
 40  #define PROCESSOR_STACKWALKER_ARM64_H__
 41  
 42  #include "google_breakpad/common/breakpad_types.h"
 43  #include "google_breakpad/common/minidump_format.h"
 44  #include "google_breakpad/processor/stackwalker.h"
 45  
 46  namespace google_breakpad {
 47  
 48  class CodeModules;
 49  
 50  class StackwalkerARM64 : public Stackwalker {
 51   public:
 52    // context is an arm64 context object that gives access to arm64-specific
 53    // register state corresponding to the innermost called frame to be
 54    // included in the stack.  The other arguments are passed directly through
 55    // to the base Stackwalker constructor.
 56    StackwalkerARM64(const SystemInfo* system_info,
 57                     const MDRawContextARM64* context,
 58                     MemoryRegion* memory,
 59                     const CodeModules* modules,
 60                     StackFrameSymbolizer* frame_symbolizer);
 61  
 62    // Change the context validity mask of the frame returned by
 63    // GetContextFrame to VALID. This is only for use by unit tests; the
 64    // default behavior is correct for all application code.
 65    void SetContextFrameValidity(uint64_t valid) {
 66      context_frame_validity_ = valid;
 67    }
 68  
 69   private:
 70    // Strip pointer authentication codes from an address.
 71    uint64_t PtrauthStrip(uint64_t ptr);
 72  
 73    // Implementation of Stackwalker, using arm64 context and stack conventions.
 74    virtual StackFrame* GetContextFrame();
 75    virtual StackFrame* GetCallerFrame(const CallStack* stack,
 76                                       bool stack_scan_allowed);
 77  
 78    // Use cfi_frame_info (derived from STACK CFI records) to construct
 79    // the frame that called frames.back(). The caller takes ownership
 80    // of the returned frame. Return NULL on failure.
 81    StackFrameARM64* GetCallerByCFIFrameInfo(const vector<StackFrame*>& frames,
 82                                             CFIFrameInfo* cfi_frame_info);
 83  
 84    // Use the frame pointer. The caller takes ownership of the returned frame.
 85    // Return NULL on failure.
 86    StackFrameARM64* GetCallerByFramePointer(const vector<StackFrame*>& frames);
 87  
 88    // Scan the stack for plausible return addresses. The caller takes ownership
 89    // of the returned frame. Return NULL on failure.
 90    StackFrameARM64* GetCallerByStackScan(const vector<StackFrame*>& frames);
 91  
 92    // GetCallerByFramePointer() depends on the previous frame having recovered
 93    // x30($LR) which may not have been done when using CFI.
 94    // This function recovers $LR in the previous frame by using the frame-pointer
 95    // two frames back to read it from the stack.
 96    void CorrectRegLRByFramePointer(const vector<StackFrame*>& frames,
 97                                    StackFrameARM64* last_frame);
 98  
 99    // Stores the CPU context corresponding to the youngest stack frame, to
100    // be returned by GetContextFrame.
101    const MDRawContextARM64* context_;
102  
103    // Validity mask for youngest stack frame. This is always
104    // CONTEXT_VALID_ALL in real use; it is only changeable for the sake of
105    // unit tests.
106    uint64_t context_frame_validity_;
107  
108    // A mask of the valid address bits, determined from the address range of
109    // modules_.
110    uint64_t address_range_mask_;
111  };
112  
113  
114  }  // namespace google_breakpad
115  
116  
117  #endif  // PROCESSOR_STACKWALKER_ARM64_H__