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1 // Copyright (c) 2010 Google Inc.
2 // All rights reserved.
3 //
4 // Redistribution and use in source and binary forms, with or without
5 // modification, are permitted provided that the following conditions are
6 // met:
7 //
8 //     * Redistributions of source code must retain the above copyright
9 // notice, this list of conditions and the following disclaimer.
10 //     * Redistributions in binary form must reproduce the above
11 // copyright notice, this list of conditions and the following disclaimer
12 // in the documentation and/or other materials provided with the
13 // distribution.
14 //     * Neither the name of Google Inc. nor the names of its
15 // contributors may be used to endorse or promote products derived from
16 // this software without specific prior written permission.
17 //
18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 
30 // stackwalker_sparc.cc: sparc-specific stackwalker.
31 //
32 // See stackwalker_sparc.h for documentation.
33 //
34 // Author: Michael Shang
35 
36 
37 #include "google_breakpad/processor/call_stack.h"
38 #include "google_breakpad/processor/memory_region.h"
39 #include "google_breakpad/processor/stack_frame_cpu.h"
40 #include "processor/logging.h"
41 #include "processor/stackwalker_sparc.h"
42 
43 namespace google_breakpad {
44 
45 
StackwalkerSPARC(const SystemInfo * system_info,const MDRawContextSPARC * context,MemoryRegion * memory,const CodeModules * modules,StackFrameSymbolizer * resolver_helper)46 StackwalkerSPARC::StackwalkerSPARC(const SystemInfo* system_info,
47                                    const MDRawContextSPARC* context,
48                                    MemoryRegion* memory,
49                                    const CodeModules* modules,
50                                    StackFrameSymbolizer* resolver_helper)
51     : Stackwalker(system_info, memory, modules, resolver_helper),
52       context_(context) {
53 }
54 
55 
GetContextFrame()56 StackFrame* StackwalkerSPARC::GetContextFrame() {
57   if (!context_) {
58     BPLOG(ERROR) << "Can't get context frame without context";
59     return NULL;
60   }
61 
62   StackFrameSPARC* frame = new StackFrameSPARC();
63 
64   // The instruction pointer is stored directly in a register, so pull it
65   // straight out of the CPU context structure.
66   frame->context = *context_;
67   frame->context_validity = StackFrameSPARC::CONTEXT_VALID_ALL;
68   frame->trust = StackFrame::FRAME_TRUST_CONTEXT;
69   frame->instruction = frame->context.pc;
70 
71   return frame;
72 }
73 
74 
GetCallerFrame(const CallStack * stack,bool stack_scan_allowed)75 StackFrame* StackwalkerSPARC::GetCallerFrame(const CallStack* stack,
76                                              bool stack_scan_allowed) {
77   if (!memory_ || !stack) {
78     BPLOG(ERROR) << "Can't get caller frame without memory or stack";
79     return NULL;
80   }
81 
82   StackFrameSPARC* last_frame = static_cast<StackFrameSPARC*>(
83       stack->frames()->back());
84 
85   // new: caller
86   // old: callee
87   // %fp, %i6 and g_r[30] is the same, see minidump_format.h
88   // %sp, %o6 and g_r[14] is the same, see minidump_format.h
89   // %sp_new = %fp_old
90   // %fp_new = *(%fp_old + 32 + 32 - 8), where the callee's %i6
91   // %pc_new = *(%fp_old + 32 + 32 - 4) + 8
92   // which is callee's %i7 plus 8
93 
94   // A caller frame must reside higher in memory than its callee frames.
95   // Anything else is an error, or an indication that we've reached the
96   // end of the stack.
97   uint64_t stack_pointer = last_frame->context.g_r[30];
98   if (stack_pointer <= last_frame->context.g_r[14]) {
99     return NULL;
100   }
101 
102   uint32_t instruction;
103   if (!memory_->GetMemoryAtAddress(stack_pointer + 60,
104                      &instruction) || instruction <= 1) {
105     return NULL;
106   }
107 
108   uint32_t stack_base;
109   if (!memory_->GetMemoryAtAddress(stack_pointer + 56,
110                      &stack_base) || stack_base <= 1) {
111     return NULL;
112   }
113 
114   StackFrameSPARC* frame = new StackFrameSPARC();
115 
116   frame->context = last_frame->context;
117   frame->context.g_r[14] = stack_pointer;
118   frame->context.g_r[30] = stack_base;
119 
120   // frame->context.pc is the return address, which is 2 instruction
121   // past the branch that caused us to arrive at the callee, which are
122   // a CALL instruction then a NOP instruction.
123   // frame_ppc->instruction to 8 less than that.  Since all sparc
124   // instructions are 4 bytes wide, this is the address of the branch
125   // instruction.  This allows source line information to match up with the
126   // line that contains a function call.  Callers that require the exact
127   // return address value may access the %i7/g_r[31] field of StackFrameSPARC.
128   frame->context.pc = instruction + 8;
129   frame->instruction = instruction;
130   frame->context_validity = StackFrameSPARC::CONTEXT_VALID_PC |
131                             StackFrameSPARC::CONTEXT_VALID_SP |
132                             StackFrameSPARC::CONTEXT_VALID_FP;
133   frame->trust = StackFrame::FRAME_TRUST_FP;
134 
135   return frame;
136 }
137 
138 
139 }  // namespace google_breakpad
140