1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
|
// Copyright (c) 2010 Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// stackwalker_arm.cc: arm-specific stackwalker.
//
// See stackwalker_arm.h for documentation.
//
// Author: Mark Mentovai, Ted Mielczarek, Jim Blandy
#include "google_breakpad/processor/call_stack.h"
#include "google_breakpad/processor/memory_region.h"
#include "google_breakpad/processor/source_line_resolver_interface.h"
#include "google_breakpad/processor/stack_frame_cpu.h"
#include "processor/cfi_frame_info.h"
#include "processor/logging.h"
#include "processor/scoped_ptr.h"
#include "processor/stackwalker_arm.h"
namespace google_breakpad {
StackwalkerARM::StackwalkerARM(const SystemInfo *system_info,
const MDRawContextARM *context,
MemoryRegion *memory,
const CodeModules *modules,
SymbolSupplier *supplier,
SourceLineResolverInterface *resolver)
: Stackwalker(system_info, memory, modules, supplier, resolver),
context_(context),
context_frame_validity_(StackFrameARM::CONTEXT_VALID_ALL) { }
StackFrame* StackwalkerARM::GetContextFrame() {
if (!context_ || !memory_) {
BPLOG(ERROR) << "Can't get context frame without context or memory";
return NULL;
}
StackFrameARM *frame = new StackFrameARM();
// The instruction pointer is stored directly in a register (r15), so pull it
// straight out of the CPU context structure.
frame->context = *context_;
frame->context_validity = context_frame_validity_;
frame->trust = StackFrame::FRAME_TRUST_CONTEXT;
frame->instruction = frame->context.iregs[15];
return frame;
}
StackFrameARM *StackwalkerARM::GetCallerByCFIFrameInfo(
const vector<StackFrame *> &frames,
CFIFrameInfo *cfi_frame_info) {
StackFrameARM *last_frame = static_cast<StackFrameARM *>(frames.back());
static const char *register_names[] = {
"r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
"r8", "r9", "r10", "r11", "r12", "sp", "lr", "pc",
"f0", "f1", "f2", "f3", "f4", "f5", "f6", "f7",
"fps", "cpsr",
NULL
};
// Populate a dictionary with the valid register values in last_frame.
CFIFrameInfo::RegisterValueMap<u_int32_t> callee_registers;
for (int i = 0; register_names[i]; i++)
if (last_frame->context_validity & StackFrameARM::RegisterValidFlag(i))
callee_registers[register_names[i]] = last_frame->context.iregs[i];
// Use the STACK CFI data to recover the caller's register values.
CFIFrameInfo::RegisterValueMap<u_int32_t> caller_registers;
if (!cfi_frame_info->FindCallerRegs(callee_registers, *memory_,
&caller_registers))
return NULL;
// Construct a new stack frame given the values the CFI recovered.
scoped_ptr<StackFrameARM> frame(new StackFrameARM());
for (int i = 0; register_names[i]; i++) {
CFIFrameInfo::RegisterValueMap<u_int32_t>::iterator entry =
caller_registers.find(register_names[i]);
if (entry != caller_registers.end()) {
// We recovered the value of this register; fill the context with the
// value from caller_registers.
frame->context_validity |= StackFrameARM::RegisterValidFlag(i);
frame->context.iregs[i] = entry->second;
} else if (4 <= i && i <= 11 && (last_frame->context_validity &
StackFrameARM::RegisterValidFlag(i))) {
// If the STACK CFI data doesn't mention some callee-saves register, and
// it is valid in the callee, assume the callee has not yet changed it.
// Registers r4 through r11 are callee-saves, according to the Procedure
// Call Standard for the ARM Architecture, which the Linux ABI follows.
frame->context_validity |= StackFrameARM::RegisterValidFlag(i);
frame->context.iregs[i] = last_frame->context.iregs[i];
}
}
// If the CFI doesn't recover the PC explicitly, then use .ra.
if (! (frame->context_validity & StackFrameARM::CONTEXT_VALID_PC)) {
CFIFrameInfo::RegisterValueMap<u_int32_t>::iterator entry =
caller_registers.find(".ra");
if (entry != caller_registers.end()) {
frame->context_validity |= StackFrameARM::CONTEXT_VALID_PC;
frame->context.iregs[MD_CONTEXT_ARM_REG_PC] = entry->second;
}
}
// If the CFI doesn't recover the SP explicitly, then use .cfa.
if (! (frame->context_validity & StackFrameARM::CONTEXT_VALID_SP)) {
CFIFrameInfo::RegisterValueMap<u_int32_t>::iterator entry =
caller_registers.find(".cfa");
if (entry != caller_registers.end()) {
frame->context_validity |= StackFrameARM::CONTEXT_VALID_SP;
frame->context.iregs[MD_CONTEXT_ARM_REG_SP] = entry->second;
}
}
// If we didn't recover the PC and the SP, then the frame isn't very useful.
static const int essentials = (StackFrameARM::CONTEXT_VALID_SP
| StackFrameARM::CONTEXT_VALID_PC);
if ((frame->context_validity & essentials) != essentials)
return NULL;
frame->trust = StackFrame::FRAME_TRUST_CFI;
return frame.release();
}
StackFrameARM *StackwalkerARM::GetCallerByStackScan(
const vector<StackFrame *> &frames) {
StackFrameARM *last_frame = static_cast<StackFrameARM *>(frames.back());
u_int32_t last_sp = last_frame->context.iregs[MD_CONTEXT_ARM_REG_SP];
u_int32_t caller_sp, caller_pc;
if (!ScanForReturnAddress(last_sp, &caller_sp, &caller_pc)) {
// No plausible return address was found.
return NULL;
}
// ScanForReturnAddress found a reasonable return address. Advance
// %sp to the location above the one where the return address was
// found.
caller_sp += 4;
// Create a new stack frame (ownership will be transferred to the caller)
// and fill it in.
StackFrameARM *frame = new StackFrameARM();
frame->trust = StackFrame::FRAME_TRUST_SCAN;
frame->context = last_frame->context;
frame->context.iregs[MD_CONTEXT_ARM_REG_PC] = caller_pc;
frame->context.iregs[MD_CONTEXT_ARM_REG_SP] = caller_sp;
frame->context_validity = StackFrameARM::CONTEXT_VALID_PC |
StackFrameARM::CONTEXT_VALID_SP;
return frame;
}
StackFrame* StackwalkerARM::GetCallerFrame(const CallStack *stack) {
if (!memory_ || !stack) {
BPLOG(ERROR) << "Can't get caller frame without memory or stack";
return NULL;
}
const vector<StackFrame *> &frames = *stack->frames();
StackFrameARM *last_frame = static_cast<StackFrameARM *>(frames.back());
scoped_ptr<StackFrameARM> frame;
// See if there is DWARF call frame information covering this address.
scoped_ptr<CFIFrameInfo> cfi_frame_info(resolver_
->FindCFIFrameInfo(last_frame));
if (cfi_frame_info.get())
frame.reset(GetCallerByCFIFrameInfo(frames, cfi_frame_info.get()));
// If CFI failed, or there wasn't CFI available, fall back
// to stack scanning.
if (!frame.get()) {
frame.reset(GetCallerByStackScan(frames));
}
// If nothing worked, tell the caller.
if (!frame.get())
return NULL;
// An instruction address of zero marks the end of the stack.
if (frame->context.iregs[MD_CONTEXT_ARM_REG_PC] == 0)
return NULL;
// If the new stack pointer is at a lower address than the old, then
// that's clearly incorrect. Treat this as end-of-stack to enforce
// progress and avoid infinite loops.
if (frame->context.iregs[MD_CONTEXT_ARM_REG_SP]
< last_frame->context.iregs[MD_CONTEXT_ARM_REG_SP])
return NULL;
// The new frame's context's PC is the return address, which is one
// instruction past the instruction that caused us to arrive at the
// callee. Set new_frame->instruction to one less than the PC. This won't
// reference the beginning of the call instruction, but it's at least
// within it, which is sufficient to get the source line information to
// match up with the line that contains the function call. Callers that
// require the exact return address value may access
// frame->context.iregs[MD_CONTEXT_ARM_REG_PC].
frame->instruction = frame->context.iregs[MD_CONTEXT_ARM_REG_PC] - 1;
return frame.release();
}
} // namespace google_breakpad
|
