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
235
236
237
238
239
240
241
242
|
// 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_amd64.cc: amd64-specific stackwalker.
//
// See stackwalker_amd64.h for documentation.
//
// Author: Mark Mentovai, Ted Mielczarek
#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_amd64.h"
namespace google_breakpad {
const StackwalkerAMD64::CFIWalker::RegisterSet
StackwalkerAMD64::cfi_register_map_[] = {
// It may seem like $rip and $rsp are callee-saves, because the callee is
// responsible for having them restored upon return. But the callee_saves
// flags here really means that the walker should assume they're
// unchanged if the CFI doesn't mention them --- clearly wrong for $rip
// and $rsp.
{ "$rax", NULL, false,
StackFrameAMD64::CONTEXT_VALID_RAX, &MDRawContextAMD64::rax },
{ "$rdx", NULL, false,
StackFrameAMD64::CONTEXT_VALID_RDX, &MDRawContextAMD64::rdx },
{ "$rcx", NULL, false,
StackFrameAMD64::CONTEXT_VALID_RCX, &MDRawContextAMD64::rcx },
{ "$rbx", NULL, true,
StackFrameAMD64::CONTEXT_VALID_RBX, &MDRawContextAMD64::rbx },
{ "$rsi", NULL, false,
StackFrameAMD64::CONTEXT_VALID_RSI, &MDRawContextAMD64::rsi },
{ "$rdi", NULL, false,
StackFrameAMD64::CONTEXT_VALID_RDI, &MDRawContextAMD64::rdi },
{ "$rbp", NULL, true,
StackFrameAMD64::CONTEXT_VALID_RBP, &MDRawContextAMD64::rbp },
{ "$rsp", ".cfa", false,
StackFrameAMD64::CONTEXT_VALID_RSP, &MDRawContextAMD64::rsp },
{ "$r8", NULL, false,
StackFrameAMD64::CONTEXT_VALID_R8, &MDRawContextAMD64::r8 },
{ "$r9", NULL, false,
StackFrameAMD64::CONTEXT_VALID_R9, &MDRawContextAMD64::r9 },
{ "$r10", NULL, false,
StackFrameAMD64::CONTEXT_VALID_R10, &MDRawContextAMD64::r10 },
{ "$r11", NULL, false,
StackFrameAMD64::CONTEXT_VALID_R11, &MDRawContextAMD64::r11 },
{ "$r12", NULL, true,
StackFrameAMD64::CONTEXT_VALID_R12, &MDRawContextAMD64::r12 },
{ "$r13", NULL, true,
StackFrameAMD64::CONTEXT_VALID_R13, &MDRawContextAMD64::r13 },
{ "$r14", NULL, true,
StackFrameAMD64::CONTEXT_VALID_R14, &MDRawContextAMD64::r14 },
{ "$r15", NULL, true,
StackFrameAMD64::CONTEXT_VALID_R15, &MDRawContextAMD64::r15 },
{ "$rip", ".ra", false,
StackFrameAMD64::CONTEXT_VALID_RIP, &MDRawContextAMD64::rip },
};
StackwalkerAMD64::StackwalkerAMD64(const SystemInfo* system_info,
const MDRawContextAMD64* context,
MemoryRegion* memory,
const CodeModules* modules,
StackFrameSymbolizer* resolver_helper)
: Stackwalker(system_info, memory, modules, resolver_helper),
context_(context),
cfi_walker_(cfi_register_map_,
(sizeof(cfi_register_map_) / sizeof(cfi_register_map_[0]))) {
}
StackFrame* StackwalkerAMD64::GetContextFrame() {
if (!context_) {
BPLOG(ERROR) << "Can't get context frame without context";
return NULL;
}
StackFrameAMD64* frame = new StackFrameAMD64();
// The instruction pointer is stored directly in a register, so pull it
// straight out of the CPU context structure.
frame->context = *context_;
frame->context_validity = StackFrameAMD64::CONTEXT_VALID_ALL;
frame->trust = StackFrame::FRAME_TRUST_CONTEXT;
frame->instruction = frame->context.rip;
return frame;
}
StackFrameAMD64* StackwalkerAMD64::GetCallerByCFIFrameInfo(
const vector<StackFrame*> &frames,
CFIFrameInfo* cfi_frame_info) {
StackFrameAMD64* last_frame = static_cast<StackFrameAMD64*>(frames.back());
scoped_ptr<StackFrameAMD64> frame(new StackFrameAMD64());
if (!cfi_walker_
.FindCallerRegisters(*memory_, *cfi_frame_info,
last_frame->context, last_frame->context_validity,
&frame->context, &frame->context_validity))
return NULL;
// Make sure we recovered all the essentials.
static const int essentials = (StackFrameAMD64::CONTEXT_VALID_RIP
| StackFrameAMD64::CONTEXT_VALID_RSP);
if ((frame->context_validity & essentials) != essentials)
return NULL;
frame->trust = StackFrame::FRAME_TRUST_CFI;
return frame.release();
}
StackFrameAMD64* StackwalkerAMD64::GetCallerByStackScan(
const vector<StackFrame*> &frames) {
StackFrameAMD64* last_frame = static_cast<StackFrameAMD64*>(frames.back());
u_int64_t last_rsp = last_frame->context.rsp;
u_int64_t caller_rip_address, caller_rip;
if (!ScanForReturnAddress(last_rsp, &caller_rip_address, &caller_rip)) {
// No plausible return address was found.
return NULL;
}
// Create a new stack frame (ownership will be transferred to the caller)
// and fill it in.
StackFrameAMD64* frame = new StackFrameAMD64();
frame->trust = StackFrame::FRAME_TRUST_SCAN;
frame->context = last_frame->context;
frame->context.rip = caller_rip;
// The caller's %rsp is directly underneath the return address pushed by
// the call.
frame->context.rsp = caller_rip_address + 8;
frame->context_validity = StackFrameAMD64::CONTEXT_VALID_RIP |
StackFrameAMD64::CONTEXT_VALID_RSP;
// Other unwinders give up if they don't have an %rbp value, so see if we
// can pass some plausible value on.
if (last_frame->context_validity & StackFrameAMD64::CONTEXT_VALID_RBP) {
// Functions typically push their caller's %rbp immediately upon entry,
// and then set %rbp to point to that. So if the callee's %rbp is
// pointing to the first word below the alleged return address, presume
// that the caller's %rbp is saved there.
if (caller_rip_address - 8 == last_frame->context.rbp) {
u_int64_t caller_rbp = 0;
if (memory_->GetMemoryAtAddress(last_frame->context.rbp, &caller_rbp) &&
caller_rbp > caller_rip_address) {
frame->context.rbp = caller_rbp;
frame->context_validity |= StackFrameAMD64::CONTEXT_VALID_RBP;
}
} else if (last_frame->context.rbp >= caller_rip_address + 8) {
// If the callee's %rbp is plausible as a value for the caller's
// %rbp, presume that the callee left it unchanged.
frame->context.rbp = last_frame->context.rbp;
frame->context_validity |= StackFrameAMD64::CONTEXT_VALID_RBP;
}
}
return frame;
}
StackFrame* StackwalkerAMD64::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();
StackFrameAMD64* last_frame = static_cast<StackFrameAMD64*>(frames.back());
scoped_ptr<StackFrameAMD64> new_frame;
// If we have DWARF CFI information, use it.
scoped_ptr<CFIFrameInfo> cfi_frame_info(
frame_symbolizer_->FindCFIFrameInfo(last_frame));
if (cfi_frame_info.get())
new_frame.reset(GetCallerByCFIFrameInfo(frames, cfi_frame_info.get()));
// If CFI failed, or there wasn't CFI available, fall back
// to stack scanning.
if (!new_frame.get()) {
new_frame.reset(GetCallerByStackScan(frames));
}
// If nothing worked, tell the caller.
if (!new_frame.get())
return NULL;
// Treat an instruction address of 0 as end-of-stack.
if (new_frame->context.rip == 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 (new_frame->context.rsp <= last_frame->context.rsp)
return NULL;
// new_frame->context.rip is the return address, which is one instruction
// past the CALL that caused us to arrive at the callee. Set
// new_frame->instruction to one less than that. This won't reference the
// beginning of the CALL instruction, but it's guaranteed to be within
// the CALL, which is sufficient to get the source line information to
// match up with the line that contains a function call. Callers that
// require the exact return address value may access the context.rip
// field of StackFrameAMD64.
new_frame->instruction = new_frame->context.rip - 1;
return new_frame.release();
}
} // namespace google_breakpad
|
