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29 | |
30 | // stackwalker_mips.cc: MIPS-specific stackwalker. |
31 | // |
32 | // See stackwalker_mips.h for documentation. |
33 | // |
34 | // Author: Tata Elxsi |
35 | |
36 | #include "common/scoped_ptr.h" |
37 | #include "google_breakpad/processor/call_stack.h" |
38 | #include "google_breakpad/processor/code_modules.h" |
39 | #include "google_breakpad/processor/memory_region.h" |
40 | #include "google_breakpad/processor/source_line_resolver_interface.h" |
41 | #include "google_breakpad/processor/stack_frame_cpu.h" |
42 | #include "processor/cfi_frame_info.h" |
43 | #include "processor/logging.h" |
44 | #include "processor/postfix_evaluator-inl.h" |
45 | #include "processor/stackwalker_mips.h" |
46 | #include "processor/windows_frame_info.h" |
47 | #include "google_breakpad/common/minidump_cpu_mips.h" |
48 | |
49 | namespace google_breakpad { |
50 | |
51 | StackwalkerMIPS::StackwalkerMIPS(const SystemInfo* system_info, |
52 | const MDRawContextMIPS* context, |
53 | MemoryRegion* memory, |
54 | const CodeModules* modules, |
55 | StackFrameSymbolizer* resolver_helper) |
56 | : Stackwalker(system_info, memory, modules, resolver_helper), |
57 | context_(context) { |
58 | if (memory_) { |
59 | if (context_->context_flags & MD_CONTEXT_MIPS64 ) { |
60 | if (0xffffffffffffffff - memory_->GetBase() < memory_->GetSize() - 1) { |
61 | BPLOG(ERROR) << "Memory out of range for stackwalking mips64: " |
62 | << HexString(memory_->GetBase()) |
63 | << "+" |
64 | << HexString(memory_->GetSize()); |
65 | memory_ = NULL; |
66 | } |
67 | } else { |
68 | if (0xffffffff - memory_->GetBase() < memory_->GetSize() - 1) { |
69 | BPLOG(ERROR) << "Memory out of range for stackwalking mips32: " |
70 | << HexString(memory_->GetBase()) |
71 | << "+" |
72 | << HexString(memory_->GetSize()); |
73 | memory_ = NULL; |
74 | } |
75 | } |
76 | } |
77 | } |
78 | |
79 | StackFrame* StackwalkerMIPS::GetContextFrame() { |
80 | if (!context_) { |
81 | BPLOG(ERROR) << "Can't get context frame without context." ; |
82 | return NULL; |
83 | } |
84 | |
85 | StackFrameMIPS* frame = new StackFrameMIPS(); |
86 | |
87 | // The instruction pointer is stored directly in a register, so pull it |
88 | // straight out of the CPU context structure. |
89 | frame->context = *context_; |
90 | frame->context_validity = StackFrameMIPS::CONTEXT_VALID_ALL; |
91 | frame->trust = StackFrame::FRAME_TRUST_CONTEXT; |
92 | frame->instruction = frame->context.epc; |
93 | |
94 | return frame; |
95 | } |
96 | |
97 | // Register names for mips. |
98 | static const char* const kRegisterNames[] = { |
99 | "$zero" , "$at" , "$v0" , "$v1" , "$a0" , "$a1" , "$a2" , "$a3" , "$to" , "$t1" , |
100 | "$t2" , "$t3" , "$t4" , "$t5" , "$t6" , "$t7" , "$s0" , "$s1" , "$s2" , "$s3" , |
101 | "$s4" , "$s5" , "$s6" , "$s7" , "$t8" , "$t9" , "$k0" , "$k1" , "$gp" , "$sp" , |
102 | "$fp" , "$ra" , NULL |
103 | // TODO(gordanac): add float point save registers |
104 | }; |
105 | |
106 | StackFrameMIPS* StackwalkerMIPS::GetCallerByCFIFrameInfo( |
107 | const vector<StackFrame*>& frames, |
108 | CFIFrameInfo* cfi_frame_info) { |
109 | StackFrameMIPS* last_frame = static_cast<StackFrameMIPS*>(frames.back()); |
110 | |
111 | if (context_->context_flags & MD_CONTEXT_MIPS) { |
112 | uint32_t pc = 0; |
113 | |
114 | // Populate a dictionary with the valid register values in last_frame. |
115 | CFIFrameInfo::RegisterValueMap<uint32_t> callee_registers; |
116 | // Use the STACK CFI data to recover the caller's register values. |
117 | CFIFrameInfo::RegisterValueMap<uint32_t> caller_registers; |
118 | |
119 | for (int i = 0; kRegisterNames[i]; ++i) { |
120 | caller_registers[kRegisterNames[i]] = last_frame->context.iregs[i]; |
121 | callee_registers[kRegisterNames[i]] = last_frame->context.iregs[i]; |
122 | } |
123 | |
124 | if (!cfi_frame_info->FindCallerRegs(callee_registers, *memory_, |
125 | &caller_registers)) { |
126 | return NULL; |
127 | } |
128 | |
129 | CFIFrameInfo::RegisterValueMap<uint32_t>::const_iterator entry = |
130 | caller_registers.find(".cfa" ); |
131 | |
132 | if (entry != caller_registers.end()) { |
133 | caller_registers["$sp" ] = entry->second; |
134 | } |
135 | |
136 | entry = caller_registers.find(".ra" ); |
137 | if (entry != caller_registers.end()) { |
138 | caller_registers["$ra" ] = entry->second; |
139 | pc = entry->second - 2 * sizeof(pc); |
140 | } |
141 | caller_registers["$pc" ] = pc; |
142 | // Construct a new stack frame given the values the CFI recovered. |
143 | scoped_ptr<StackFrameMIPS> frame(new StackFrameMIPS()); |
144 | |
145 | for (int i = 0; kRegisterNames[i]; ++i) { |
146 | CFIFrameInfo::RegisterValueMap<uint32_t>::const_iterator caller_entry = |
147 | caller_registers.find(kRegisterNames[i]); |
148 | |
149 | if (caller_entry != caller_registers.end()) { |
150 | // The value of this register is recovered; fill the context with the |
151 | // value from caller_registers. |
152 | frame->context.iregs[i] = caller_entry->second; |
153 | frame->context_validity |= StackFrameMIPS::RegisterValidFlag(i); |
154 | } else if (((i >= INDEX_MIPS_REG_S0 && i <= INDEX_MIPS_REG_S7) || |
155 | (i > INDEX_MIPS_REG_GP && i < INDEX_MIPS_REG_RA)) && |
156 | (last_frame->context_validity & |
157 | StackFrameMIPS::RegisterValidFlag(i))) { |
158 | // If the STACK CFI data doesn't mention some callee-save register, and |
159 | // it is valid in the callee, assume the callee has not yet changed it. |
160 | // Calee-save registers according to the MIPS o32 ABI specification are: |
161 | // $s0 to $s7 |
162 | // $sp, $s8 |
163 | frame->context.iregs[i] = last_frame->context.iregs[i]; |
164 | frame->context_validity |= StackFrameMIPS::RegisterValidFlag(i); |
165 | } |
166 | } |
167 | |
168 | frame->context.epc = caller_registers["$pc" ]; |
169 | frame->instruction = caller_registers["$pc" ]; |
170 | frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_PC; |
171 | |
172 | frame->context.iregs[MD_CONTEXT_MIPS_REG_RA] = caller_registers["$ra" ]; |
173 | frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_RA; |
174 | |
175 | frame->trust = StackFrame::FRAME_TRUST_CFI; |
176 | |
177 | return frame.release(); |
178 | } else { |
179 | uint64_t pc = 0; |
180 | |
181 | // Populate a dictionary with the valid register values in last_frame. |
182 | CFIFrameInfo::RegisterValueMap<uint64_t> callee_registers; |
183 | // Use the STACK CFI data to recover the caller's register values. |
184 | CFIFrameInfo::RegisterValueMap<uint64_t> caller_registers; |
185 | |
186 | for (int i = 0; kRegisterNames[i]; ++i) { |
187 | caller_registers[kRegisterNames[i]] = last_frame->context.iregs[i]; |
188 | callee_registers[kRegisterNames[i]] = last_frame->context.iregs[i]; |
189 | } |
190 | |
191 | if (!cfi_frame_info->FindCallerRegs(callee_registers, *memory_, |
192 | &caller_registers)) { |
193 | return NULL; |
194 | } |
195 | |
196 | CFIFrameInfo::RegisterValueMap<uint64_t>::const_iterator entry = |
197 | caller_registers.find(".cfa" ); |
198 | |
199 | if (entry != caller_registers.end()) { |
200 | caller_registers["$sp" ] = entry->second; |
201 | } |
202 | |
203 | entry = caller_registers.find(".ra" ); |
204 | if (entry != caller_registers.end()) { |
205 | caller_registers["$ra" ] = entry->second; |
206 | pc = entry->second - 2 * sizeof(pc); |
207 | } |
208 | caller_registers["$pc" ] = pc; |
209 | // Construct a new stack frame given the values the CFI recovered. |
210 | scoped_ptr<StackFrameMIPS> frame(new StackFrameMIPS()); |
211 | |
212 | for (int i = 0; kRegisterNames[i]; ++i) { |
213 | CFIFrameInfo::RegisterValueMap<uint64_t>::const_iterator caller_entry = |
214 | caller_registers.find(kRegisterNames[i]); |
215 | |
216 | if (caller_entry != caller_registers.end()) { |
217 | // The value of this register is recovered; fill the context with the |
218 | // value from caller_registers. |
219 | frame->context.iregs[i] = caller_entry->second; |
220 | frame->context_validity |= StackFrameMIPS::RegisterValidFlag(i); |
221 | } else if (((i >= INDEX_MIPS_REG_S0 && i <= INDEX_MIPS_REG_S7) || |
222 | (i >= INDEX_MIPS_REG_GP && i < INDEX_MIPS_REG_RA)) && |
223 | (last_frame->context_validity & |
224 | StackFrameMIPS::RegisterValidFlag(i))) { |
225 | // If the STACK CFI data doesn't mention some callee-save register, and |
226 | // it is valid in the callee, assume the callee has not yet changed it. |
227 | // Calee-save registers according to the MIPS o32 ABI specification are: |
228 | // $s0 to $s7 |
229 | // $sp, $s8 |
230 | frame->context.iregs[i] = last_frame->context.iregs[i]; |
231 | frame->context_validity |= StackFrameMIPS::RegisterValidFlag(i); |
232 | } |
233 | } |
234 | |
235 | frame->context.epc = caller_registers["$pc" ]; |
236 | frame->instruction = caller_registers["$pc" ]; |
237 | frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_PC; |
238 | |
239 | frame->context.iregs[MD_CONTEXT_MIPS_REG_RA] = caller_registers["$ra" ]; |
240 | frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_RA; |
241 | |
242 | frame->trust = StackFrame::FRAME_TRUST_CFI; |
243 | |
244 | return frame.release(); |
245 | } |
246 | } |
247 | |
248 | StackFrame* StackwalkerMIPS::GetCallerFrame(const CallStack* stack, |
249 | bool stack_scan_allowed) { |
250 | if (!memory_ || !stack) { |
251 | BPLOG(ERROR) << "Can't get caller frame without memory or stack" ; |
252 | return NULL; |
253 | } |
254 | |
255 | const vector<StackFrame*>& frames = *stack->frames(); |
256 | StackFrameMIPS* last_frame = static_cast<StackFrameMIPS*>(frames.back()); |
257 | scoped_ptr<StackFrameMIPS> new_frame; |
258 | |
259 | // See if there is DWARF call frame information covering this address. |
260 | scoped_ptr<CFIFrameInfo> cfi_frame_info( |
261 | frame_symbolizer_->FindCFIFrameInfo(last_frame)); |
262 | if (cfi_frame_info.get()) |
263 | new_frame.reset(GetCallerByCFIFrameInfo(frames, cfi_frame_info.get())); |
264 | |
265 | // If caller frame is not found in CFI try analyzing the stack. |
266 | if (stack_scan_allowed && !new_frame.get()) { |
267 | new_frame.reset(GetCallerByStackScan(frames)); |
268 | } |
269 | |
270 | // If nothing worked, tell the caller. |
271 | if (!new_frame.get()) { |
272 | return NULL; |
273 | } |
274 | |
275 | // Should we terminate the stack walk? (end-of-stack or broken invariant) |
276 | if (TerminateWalk(new_frame->context.epc, |
277 | new_frame->context.iregs[MD_CONTEXT_MIPS_REG_SP], |
278 | last_frame->context.iregs[MD_CONTEXT_MIPS_REG_SP], |
279 | frames.size() == 1)) { |
280 | return NULL; |
281 | } |
282 | |
283 | return new_frame.release(); |
284 | } |
285 | |
286 | StackFrameMIPS* StackwalkerMIPS::GetCallerByStackScan( |
287 | const vector<StackFrame*>& frames) { |
288 | const uint32_t kMaxFrameStackSize = 1024; |
289 | const uint32_t kMinArgsOnStack = 4; |
290 | |
291 | StackFrameMIPS* last_frame = static_cast<StackFrameMIPS*>(frames.back()); |
292 | |
293 | if (context_->context_flags & MD_CONTEXT_MIPS) { |
294 | uint32_t last_sp = last_frame->context.iregs[MD_CONTEXT_MIPS_REG_SP]; |
295 | uint32_t caller_pc, caller_sp, caller_fp; |
296 | |
297 | // Return address cannot be obtained directly. |
298 | // Force stackwalking. |
299 | |
300 | // We cannot use frame pointer to get the return address. |
301 | // We'll scan the stack for a |
302 | // return address. This can happen if last_frame is executing code |
303 | // for a module for which we don't have symbols. |
304 | int count = kMaxFrameStackSize / sizeof(caller_pc); |
305 | |
306 | if (frames.size() > 1) { |
307 | // In case of mips32 ABI stack frame of a nonleaf function |
308 | // must have minimum stack frame assigned for 4 arguments (4 words). |
309 | // Move stack pointer for 4 words to avoid reporting non-existing frames |
310 | // for all frames except the topmost one. |
311 | // There is no way of knowing if topmost frame belongs to a leaf or |
312 | // a nonleaf function. |
313 | last_sp += kMinArgsOnStack * sizeof(caller_pc); |
314 | // Adjust 'count' so that return address is scanned only in limits |
315 | // of one stack frame. |
316 | count -= kMinArgsOnStack; |
317 | } |
318 | |
319 | do { |
320 | // Scanning for return address from stack pointer of the last frame. |
321 | if (!ScanForReturnAddress(last_sp, &caller_sp, &caller_pc, count)) { |
322 | // If we can't find an instruction pointer even with stack scanning, |
323 | // give up. |
324 | BPLOG(ERROR) << " ScanForReturnAddress failed " ; |
325 | return NULL; |
326 | } |
327 | // Get $fp stored in the stack frame. |
328 | if (!memory_->GetMemoryAtAddress(caller_sp - sizeof(caller_pc), |
329 | &caller_fp)) { |
330 | BPLOG(INFO) << " GetMemoryAtAddress for fp failed " ; |
331 | return NULL; |
332 | } |
333 | |
334 | count = count - (caller_sp - last_sp) / sizeof(caller_pc); |
335 | // Now scan the next address in the stack. |
336 | last_sp = caller_sp + sizeof(caller_pc); |
337 | } while ((caller_fp - caller_sp >= kMaxFrameStackSize) && count > 0); |
338 | |
339 | if (!count) { |
340 | BPLOG(INFO) << " No frame found " ; |
341 | return NULL; |
342 | } |
343 | |
344 | // ScanForReturnAddress found a reasonable return address. Advance |
345 | // $sp to the location above the one where the return address was |
346 | // found. |
347 | caller_sp += sizeof(caller_pc); |
348 | // caller_pc is actually containing $ra value; |
349 | // $pc is two instructions before $ra, |
350 | // so the caller_pc needs to be decremented accordingly. |
351 | caller_pc -= 2 * sizeof(caller_pc); |
352 | |
353 | // Create a new stack frame (ownership will be transferred to the caller) |
354 | // and fill it in. |
355 | StackFrameMIPS* frame = new StackFrameMIPS(); |
356 | frame->trust = StackFrame::FRAME_TRUST_SCAN; |
357 | frame->context = last_frame->context; |
358 | frame->context.epc = caller_pc; |
359 | frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_PC; |
360 | frame->instruction = caller_pc; |
361 | |
362 | frame->context.iregs[MD_CONTEXT_MIPS_REG_SP] = caller_sp; |
363 | frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_SP; |
364 | frame->context.iregs[MD_CONTEXT_MIPS_REG_FP] = caller_fp; |
365 | frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_FP; |
366 | |
367 | frame->context.iregs[MD_CONTEXT_MIPS_REG_RA] = |
368 | caller_pc + 2 * sizeof(caller_pc); |
369 | frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_RA; |
370 | |
371 | return frame; |
372 | } else { |
373 | uint64_t last_sp = last_frame->context.iregs[MD_CONTEXT_MIPS_REG_SP]; |
374 | uint64_t caller_pc, caller_sp, caller_fp; |
375 | |
376 | // Return address cannot be obtained directly. |
377 | // Force stackwalking. |
378 | |
379 | // We cannot use frame pointer to get the return address. |
380 | // We'll scan the stack for a |
381 | // return address. This can happen if last_frame is executing code |
382 | // for a module for which we don't have symbols. |
383 | int count = kMaxFrameStackSize / sizeof(caller_pc); |
384 | |
385 | do { |
386 | // Scanning for return address from stack pointer of the last frame. |
387 | if (!ScanForReturnAddress(last_sp, &caller_sp, &caller_pc, count)) { |
388 | // If we can't find an instruction pointer even with stack scanning, |
389 | // give up. |
390 | BPLOG(ERROR) << " ScanForReturnAddress failed " ; |
391 | return NULL; |
392 | } |
393 | // Get $fp stored in the stack frame. |
394 | if (!memory_->GetMemoryAtAddress(caller_sp - sizeof(caller_pc), |
395 | &caller_fp)) { |
396 | BPLOG(INFO) << " GetMemoryAtAddress for fp failed " ; |
397 | return NULL; |
398 | } |
399 | |
400 | count = count - (caller_sp - last_sp) / sizeof(caller_pc); |
401 | // Now scan the next address in the stack. |
402 | last_sp = caller_sp + sizeof(caller_pc); |
403 | } while ((caller_fp - caller_sp >= kMaxFrameStackSize) && count > 0); |
404 | |
405 | if (!count) { |
406 | BPLOG(INFO) << " No frame found " ; |
407 | return NULL; |
408 | } |
409 | |
410 | // ScanForReturnAddress found a reasonable return address. Advance |
411 | // $sp to the location above the one where the return address was |
412 | // found. |
413 | caller_sp += sizeof(caller_pc); |
414 | // caller_pc is actually containing $ra value; |
415 | // $pc is two instructions before $ra, |
416 | // so the caller_pc needs to be decremented accordingly. |
417 | caller_pc -= 2 * sizeof(caller_pc); |
418 | |
419 | // Create a new stack frame (ownership will be transferred to the caller) |
420 | // and fill it in. |
421 | StackFrameMIPS* frame = new StackFrameMIPS(); |
422 | frame->trust = StackFrame::FRAME_TRUST_SCAN; |
423 | frame->context = last_frame->context; |
424 | frame->context.epc = caller_pc; |
425 | frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_PC; |
426 | frame->instruction = caller_pc; |
427 | |
428 | frame->context.iregs[MD_CONTEXT_MIPS_REG_SP] = caller_sp; |
429 | frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_SP; |
430 | frame->context.iregs[MD_CONTEXT_MIPS_REG_FP] = caller_fp; |
431 | frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_FP; |
432 | |
433 | frame->context.iregs[MD_CONTEXT_MIPS_REG_RA] = |
434 | caller_pc + 2 * sizeof(caller_pc); |
435 | frame->context_validity |= StackFrameMIPS::CONTEXT_VALID_RA; |
436 | |
437 | return frame; |
438 | } |
439 | } |
440 | |
441 | } // namespace google_breakpad |
442 | |
443 | |