Jeff Brown | 501edd2 | 2011-10-19 20:35:35 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright (C) 2011 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | /* |
| 18 | * Backtracing functions for ARM. |
| 19 | * |
| 20 | * This implementation uses the exception unwinding tables provided by |
| 21 | * the compiler to unwind call frames. Refer to the ARM Exception Handling ABI |
| 22 | * documentation (EHABI) for more details about what's going on here. |
| 23 | * |
| 24 | * An ELF binary may contain an EXIDX section that provides an index to |
| 25 | * the exception handling table of each function, sorted by program |
| 26 | * counter address. |
| 27 | * |
| 28 | * When the executable is statically linked, the EXIDX section can be |
| 29 | * accessed by querying the values of the __exidx_start and __exidx_end |
| 30 | * symbols. That said, this library is currently only compiled as |
| 31 | * a dynamic library, so we will not trouble ourselves with statically |
| 32 | * linked executables any further. |
| 33 | * |
| 34 | * When the Bionic dynamic linker is used, it exports a function called |
| 35 | * dl_unwind_find_exidx that obtains the EXIDX section for a given |
| 36 | * absolute program counter address. |
| 37 | * |
| 38 | * This implementation also supports unwinding other processes via ptrace(). |
| 39 | * In that case, the EXIDX section is found by reading the ELF section table |
| 40 | * structures using ptrace(). |
| 41 | * |
| 42 | * Because the tables are used for exception handling, it can happen that |
| 43 | * a given function will not have an exception handling table. In particular, |
| 44 | * exceptions are assumes to only ever be thrown at call sites. Therefore, |
| 45 | * by definition leaf functions will not have exception handling tables. |
| 46 | * This may make unwinding impossible in some cases although we can still get |
| 47 | * some idea of the call stack by examining the PC and LR registers. |
| 48 | * |
| 49 | * As we are only interested in backtrace information, we do not need |
| 50 | * to perform all of the work of unwinding such as restoring register |
| 51 | * state and running cleanup functions. Unwinding is performed virtually on |
| 52 | * an abstract machine context consisting of just the ARM core registers. |
| 53 | * Furthermore, we do not run generic "personality functions" because |
| 54 | * we may not be in a position to execute arbitrary code, especially if |
| 55 | * we are running in a signal handler or using ptrace()! |
| 56 | */ |
| 57 | |
| 58 | #define LOG_TAG "Corkscrew" |
| 59 | //#define LOG_NDEBUG 0 |
| 60 | |
| 61 | #include "../backtrace-arch.h" |
| 62 | #include "../backtrace-helper.h" |
| 63 | #include "../ptrace-arch.h" |
| 64 | #include <corkscrew/ptrace.h> |
| 65 | |
| 66 | #include <stdlib.h> |
| 67 | #include <signal.h> |
| 68 | #include <stdbool.h> |
| 69 | #include <limits.h> |
| 70 | #include <errno.h> |
| 71 | #include <sys/ptrace.h> |
| 72 | #include <sys/exec_elf.h> |
| 73 | #include <cutils/log.h> |
| 74 | |
| 75 | /* Machine context at the time a signal was raised. */ |
| 76 | typedef struct ucontext { |
| 77 | uint32_t uc_flags; |
| 78 | struct ucontext* uc_link; |
| 79 | stack_t uc_stack; |
| 80 | struct sigcontext { |
| 81 | uint32_t trap_no; |
| 82 | uint32_t error_code; |
| 83 | uint32_t oldmask; |
| 84 | uint32_t gregs[16]; |
| 85 | uint32_t arm_cpsr; |
| 86 | uint32_t fault_address; |
| 87 | } uc_mcontext; |
| 88 | uint32_t uc_sigmask; |
| 89 | } ucontext_t; |
| 90 | |
| 91 | /* Unwind state. */ |
| 92 | typedef struct { |
| 93 | uint32_t gregs[16]; |
| 94 | } unwind_state_t; |
| 95 | |
| 96 | static const int R_SP = 13; |
| 97 | static const int R_LR = 14; |
| 98 | static const int R_PC = 15; |
| 99 | |
| 100 | /* Special EXIDX value that indicates that a frame cannot be unwound. */ |
| 101 | static const uint32_t EXIDX_CANTUNWIND = 1; |
| 102 | |
| 103 | /* The function exported by the Bionic linker to find the EXIDX |
| 104 | * table for a given program counter address. */ |
| 105 | extern uintptr_t dl_unwind_find_exidx(uintptr_t pc, size_t* out_exidx_size); |
| 106 | |
| 107 | /* Transforms a 31-bit place-relative offset to an absolute address. |
| 108 | * We assume the most significant bit is clear. */ |
| 109 | static uintptr_t prel_to_absolute(uintptr_t place, uint32_t prel_offset) { |
| 110 | return place + (((int32_t)(prel_offset << 1)) >> 1); |
| 111 | } |
| 112 | |
| 113 | static uintptr_t get_exception_handler( |
| 114 | const ptrace_context_t* context, pid_t tid, uintptr_t pc) { |
| 115 | uintptr_t exidx_start; |
| 116 | size_t exidx_size; |
| 117 | if (tid < 0) { |
| 118 | exidx_start = dl_unwind_find_exidx(pc, &exidx_size); |
| 119 | } else { |
| 120 | const map_info_t* mi = find_map_info(context->map_info_list, pc); |
| 121 | if (mi && mi->data) { |
| 122 | const map_info_data_t* data = (const map_info_data_t*)mi->data; |
| 123 | exidx_start = data->exidx_start; |
| 124 | exidx_size = data->exidx_size; |
| 125 | } else { |
| 126 | exidx_start = 0; |
| 127 | exidx_size = 0; |
| 128 | } |
| 129 | } |
| 130 | |
| 131 | // The PC points to the instruction following the branch. |
| 132 | // We want to find the exception handler entry that corresponds to the branch itself, |
| 133 | // so we offset the PC backwards into the previous instruction. |
| 134 | // ARM instructions are 4 bytes, Thumb are 2, so we just subtract two so we either |
| 135 | // end up in the middle (ARM) or at the beginning of the instruction (Thumb). |
| 136 | if (pc >= 2) { |
| 137 | pc -= 2; |
| 138 | } |
| 139 | |
| 140 | uint32_t handler = 0; |
| 141 | if (exidx_start) { |
| 142 | uint32_t low = 0; |
| 143 | uint32_t high = exidx_size; |
| 144 | while (low < high) { |
| 145 | uint32_t index = (low + high) / 2; |
| 146 | uintptr_t entry = exidx_start + index * 8; |
| 147 | uint32_t entry_prel_pc; |
| 148 | if (!try_get_word(tid, entry, &entry_prel_pc)) { |
| 149 | break; |
| 150 | } |
| 151 | uintptr_t entry_pc = prel_to_absolute(entry, entry_prel_pc); |
| 152 | if (pc < entry_pc) { |
| 153 | high = index; |
| 154 | continue; |
| 155 | } |
| 156 | if (index + 1 < exidx_size) { |
| 157 | uintptr_t next_entry = entry + 8; |
| 158 | uint32_t next_entry_prel_pc; |
| 159 | if (!try_get_word(tid, next_entry, &next_entry_prel_pc)) { |
| 160 | break; |
| 161 | } |
| 162 | uintptr_t next_entry_pc = prel_to_absolute(next_entry, next_entry_prel_pc); |
| 163 | if (pc >= next_entry_pc) { |
| 164 | low = index + 1; |
| 165 | continue; |
| 166 | } |
| 167 | } |
| 168 | |
| 169 | uintptr_t entry_handler_ptr = entry + 4; |
| 170 | uint32_t entry_handler; |
| 171 | if (!try_get_word(tid, entry_handler_ptr, &entry_handler)) { |
| 172 | break; |
| 173 | } |
| 174 | if (entry_handler & (1L << 31)) { |
| 175 | handler = entry_handler_ptr; // in-place handler data |
| 176 | } else if (entry_handler != EXIDX_CANTUNWIND) { |
| 177 | handler = prel_to_absolute(entry_handler_ptr, entry_handler); |
| 178 | } |
| 179 | break; |
| 180 | } |
| 181 | } |
| 182 | LOGV("get handler: pc=0x%08x, exidx_start=0x%08x, exidx_size=%d, handler=0x%08x", |
| 183 | pc, exidx_start, exidx_size, handler); |
| 184 | return handler; |
| 185 | } |
| 186 | |
| 187 | typedef struct { |
| 188 | uintptr_t ptr; |
| 189 | uint32_t word; |
| 190 | } byte_stream_t; |
| 191 | |
| 192 | static bool try_next_byte(pid_t tid, byte_stream_t* stream, uint8_t* out_value) { |
| 193 | uint8_t result; |
| 194 | switch (stream->ptr & 3) { |
| 195 | case 0: |
| 196 | if (!try_get_word(tid, stream->ptr, &stream->word)) { |
| 197 | *out_value = 0; |
| 198 | return false; |
| 199 | } |
| 200 | *out_value = stream->word >> 24; |
| 201 | break; |
| 202 | |
| 203 | case 1: |
| 204 | *out_value = stream->word >> 16; |
| 205 | break; |
| 206 | |
| 207 | case 2: |
| 208 | *out_value = stream->word >> 8; |
| 209 | break; |
| 210 | |
| 211 | default: |
| 212 | *out_value = stream->word; |
| 213 | break; |
| 214 | } |
| 215 | |
| 216 | LOGV("next_byte: ptr=0x%08x, value=0x%02x", stream->ptr, *out_value); |
| 217 | stream->ptr += 1; |
| 218 | return true; |
| 219 | } |
| 220 | |
| 221 | static void set_reg(unwind_state_t* state, uint32_t reg, uint32_t value) { |
| 222 | LOGV("set_reg: reg=%d, value=0x%08x", reg, value); |
| 223 | state->gregs[reg] = value; |
| 224 | } |
| 225 | |
| 226 | static bool try_pop_registers(pid_t tid, unwind_state_t* state, uint32_t mask) { |
| 227 | uint32_t sp = state->gregs[R_SP]; |
| 228 | bool sp_updated = false; |
| 229 | for (int i = 0; i < 16; i++) { |
| 230 | if (mask & (1 << i)) { |
| 231 | uint32_t value; |
| 232 | if (!try_get_word(tid, sp, &value)) { |
| 233 | return false; |
| 234 | } |
| 235 | if (i == R_SP) { |
| 236 | sp_updated = true; |
| 237 | } |
| 238 | set_reg(state, i, value); |
| 239 | sp += 4; |
| 240 | } |
| 241 | } |
| 242 | if (!sp_updated) { |
| 243 | set_reg(state, R_SP, sp); |
| 244 | } |
| 245 | return true; |
| 246 | } |
| 247 | |
| 248 | /* Executes a built-in personality routine as defined in the EHABI. |
| 249 | * Returns true if unwinding should continue. |
| 250 | * |
| 251 | * The data for the built-in personality routines consists of a sequence |
| 252 | * of unwinding instructions, followed by a sequence of scope descriptors, |
| 253 | * each of which has a length and offset encoded using 16-bit or 32-bit |
| 254 | * values. |
| 255 | * |
| 256 | * We only care about the unwinding instructions. They specify the |
| 257 | * operations of an abstract machine whose purpose is to transform the |
| 258 | * virtual register state (including the stack pointer) such that |
| 259 | * the call frame is unwound and the PC register points to the call site. |
| 260 | */ |
| 261 | static bool execute_personality_routine(pid_t tid, unwind_state_t* state, |
| 262 | byte_stream_t* stream, int pr_index) { |
| 263 | size_t size; |
| 264 | switch (pr_index) { |
| 265 | case 0: // Personality routine #0, short frame, descriptors have 16-bit scope. |
| 266 | size = 3; |
| 267 | break; |
| 268 | case 1: // Personality routine #1, long frame, descriptors have 16-bit scope. |
| 269 | case 2: { // Personality routine #2, long frame, descriptors have 32-bit scope. |
| 270 | uint8_t size_byte; |
| 271 | if (!try_next_byte(tid, stream, &size_byte)) { |
| 272 | return false; |
| 273 | } |
| 274 | size = (uint32_t)size_byte * sizeof(uint32_t) + 2; |
| 275 | break; |
| 276 | } |
| 277 | default: // Unknown personality routine. Stop here. |
| 278 | return false; |
| 279 | } |
| 280 | |
| 281 | bool pc_was_set = false; |
| 282 | while (size--) { |
| 283 | uint8_t op; |
| 284 | if (!try_next_byte(tid, stream, &op)) { |
| 285 | return false; |
| 286 | } |
| 287 | if ((op & 0xc0) == 0x00) { |
| 288 | // "vsp = vsp + (xxxxxx << 2) + 4" |
| 289 | set_reg(state, R_SP, state->gregs[R_SP] + ((op & 0x3f) << 2) + 4); |
| 290 | } else if ((op & 0xc0) == 0x40) { |
| 291 | // "vsp = vsp - (xxxxxx << 2) - 4" |
| 292 | set_reg(state, R_SP, state->gregs[R_SP] - ((op & 0x3f) << 2) - 4); |
| 293 | } else if ((op & 0xf0) == 0x80) { |
| 294 | uint8_t op2; |
| 295 | if (!(size--) || !try_next_byte(tid, stream, &op2)) { |
| 296 | return false; |
| 297 | } |
| 298 | uint32_t mask = (((uint32_t)op & 0x0f) << 12) | ((uint32_t)op2 << 4); |
| 299 | if (mask) { |
| 300 | // "Pop up to 12 integer registers under masks {r15-r12}, {r11-r4}" |
| 301 | if (!try_pop_registers(tid, state, mask)) { |
| 302 | return false; |
| 303 | } |
| 304 | if (mask & (1 << R_PC)) { |
| 305 | pc_was_set = true; |
| 306 | } |
| 307 | } else { |
| 308 | // "Refuse to unwind" |
| 309 | return false; |
| 310 | } |
| 311 | } else if ((op & 0xf0) == 0x90) { |
| 312 | if (op != 0x9d && op != 0x9f) { |
| 313 | // "Set vsp = r[nnnn]" |
| 314 | set_reg(state, R_SP, state->gregs[op & 0x0f]); |
| 315 | } else { |
| 316 | // "Reserved as prefix for ARM register to register moves" |
| 317 | // "Reserved as prefix for Intel Wireless MMX register to register moves" |
| 318 | return false; |
| 319 | } |
| 320 | } else if ((op & 0xf8) == 0xa0) { |
| 321 | // "Pop r4-r[4+nnn]" |
| 322 | uint32_t mask = (0x0ff0 >> (7 - (op & 0x07))) & 0x0ff0; |
| 323 | if (!try_pop_registers(tid, state, mask)) { |
| 324 | return false; |
| 325 | } |
| 326 | } else if ((op & 0xf8) == 0xa8) { |
| 327 | // "Pop r4-r[4+nnn], r14" |
| 328 | uint32_t mask = ((0x0ff0 >> (7 - (op & 0x07))) & 0x0ff0) | 0x4000; |
| 329 | if (!try_pop_registers(tid, state, mask)) { |
| 330 | return false; |
| 331 | } |
| 332 | } else if (op == 0xb0) { |
| 333 | // "Finish" |
| 334 | break; |
| 335 | } else if (op == 0xb1) { |
| 336 | uint8_t op2; |
| 337 | if (!(size--) || !try_next_byte(tid, stream, &op2)) { |
| 338 | return false; |
| 339 | } |
| 340 | if (op2 != 0x00 && (op2 & 0xf0) == 0x00) { |
| 341 | // "Pop integer registers under mask {r3, r2, r1, r0}" |
| 342 | if (!try_pop_registers(tid, state, op2)) { |
| 343 | return false; |
| 344 | } |
| 345 | } else { |
| 346 | // "Spare" |
| 347 | return false; |
| 348 | } |
| 349 | } else if (op == 0xb2) { |
| 350 | // "vsp = vsp + 0x204 + (uleb128 << 2)" |
| 351 | uint32_t value = 0; |
| 352 | uint32_t shift = 0; |
| 353 | uint8_t op2; |
| 354 | do { |
| 355 | if (!(size--) || !try_next_byte(tid, stream, &op2)) { |
| 356 | return false; |
| 357 | } |
| 358 | value |= (op2 & 0x7f) << shift; |
| 359 | shift += 7; |
| 360 | } while (op2 & 0x80); |
| 361 | set_reg(state, R_SP, state->gregs[R_SP] + (value << 2) + 0x204); |
| 362 | } else if (op == 0xb3) { |
| 363 | // "Pop VFP double-precision registers D[ssss]-D[ssss+cccc] saved (as if) by FSTMFDX" |
| 364 | uint8_t op2; |
| 365 | if (!(size--) || !try_next_byte(tid, stream, &op2)) { |
| 366 | return false; |
| 367 | } |
| 368 | set_reg(state, R_SP, state->gregs[R_SP] + (uint32_t)(op2 & 0x0f) * 8 + 12); |
| 369 | } else if ((op & 0xf8) == 0xb8) { |
| 370 | // "Pop VFP double-precision registers D[8]-D[8+nnn] saved (as if) by FSTMFDX" |
| 371 | set_reg(state, R_SP, state->gregs[R_SP] + (uint32_t)(op & 0x07) * 8 + 12); |
| 372 | } else if ((op & 0xf8) == 0xc0) { |
| 373 | // "Intel Wireless MMX pop wR[10]-wR[10+nnn]" |
| 374 | set_reg(state, R_SP, state->gregs[R_SP] + (uint32_t)(op & 0x07) * 8 + 8); |
| 375 | } else if (op == 0xc6) { |
| 376 | // "Intel Wireless MMX pop wR[ssss]-wR[ssss+cccc]" |
| 377 | uint8_t op2; |
| 378 | if (!(size--) || !try_next_byte(tid, stream, &op2)) { |
| 379 | return false; |
| 380 | } |
| 381 | set_reg(state, R_SP, state->gregs[R_SP] + (uint32_t)(op2 & 0x0f) * 8 + 8); |
| 382 | } else if (op == 0xc7) { |
| 383 | uint8_t op2; |
| 384 | if (!(size--) || !try_next_byte(tid, stream, &op2)) { |
| 385 | return false; |
| 386 | } |
| 387 | if (op2 != 0x00 && (op2 & 0xf0) == 0x00) { |
| 388 | // "Intel Wireless MMX pop wCGR registers under mask {wCGR3,2,1,0}" |
| 389 | set_reg(state, R_SP, state->gregs[R_SP] + __builtin_popcount(op2) * 4); |
| 390 | } else { |
| 391 | // "Spare" |
| 392 | return false; |
| 393 | } |
| 394 | } else if (op == 0xc8) { |
| 395 | // "Pop VFP double precision registers D[16+ssss]-D[16+ssss+cccc] |
| 396 | // saved (as if) by FSTMFD" |
| 397 | uint8_t op2; |
| 398 | if (!(size--) || !try_next_byte(tid, stream, &op2)) { |
| 399 | return false; |
| 400 | } |
| 401 | set_reg(state, R_SP, state->gregs[R_SP] + (uint32_t)(op2 & 0x0f) * 8 + 8); |
| 402 | } else if (op == 0xc9) { |
| 403 | // "Pop VFP double precision registers D[ssss]-D[ssss+cccc] saved (as if) by FSTMFDD" |
| 404 | uint8_t op2; |
| 405 | if (!(size--) || !try_next_byte(tid, stream, &op2)) { |
| 406 | return false; |
| 407 | } |
| 408 | set_reg(state, R_SP, state->gregs[R_SP] + (uint32_t)(op2 & 0x0f) * 8 + 8); |
| 409 | } else if ((op == 0xf8) == 0xd0) { |
| 410 | // "Pop VFP double-precision registers D[8]-D[8+nnn] saved (as if) by FSTMFDD" |
| 411 | set_reg(state, R_SP, state->gregs[R_SP] + (uint32_t)(op & 0x07) * 8 + 8); |
| 412 | } else { |
| 413 | // "Spare" |
| 414 | return false; |
| 415 | } |
| 416 | } |
| 417 | if (!pc_was_set) { |
| 418 | set_reg(state, R_PC, state->gregs[R_LR]); |
| 419 | } |
| 420 | return true; |
| 421 | } |
| 422 | |
| 423 | static ssize_t unwind_backtrace_common(pid_t tid, const ptrace_context_t* context, |
| 424 | unwind_state_t* state, backtrace_frame_t* backtrace, |
| 425 | size_t ignore_depth, size_t max_depth) { |
| 426 | size_t ignored_frames = 0; |
| 427 | size_t returned_frames = 0; |
| 428 | |
| 429 | uintptr_t handler = get_exception_handler(context, tid, state->gregs[R_PC]); |
| 430 | if (!handler) { |
| 431 | // If there is no handler for the PC, the program may have branched to |
| 432 | // an invalid address. Check whether we have a handler for the LR |
| 433 | // where we came from and use that instead. |
| 434 | backtrace_frame_t* frame = add_backtrace_entry(state->gregs[R_PC], backtrace, |
| 435 | ignore_depth, max_depth, &ignored_frames, &returned_frames); |
| 436 | if (frame) { |
| 437 | frame->stack_top = state->gregs[R_SP]; |
| 438 | } |
| 439 | |
| 440 | handler = get_exception_handler(context, tid, state->gregs[R_LR]); |
| 441 | if (!handler) { |
| 442 | // We don't have a handler here either. Unwinding will not be possible. |
| 443 | // Return the PC and LR (if it looks sane) and call it good. |
| 444 | if (state->gregs[R_LR] && state->gregs[R_LR] != state->gregs[R_PC]) { |
| 445 | // Don't return the SP for this second frame because we don't |
| 446 | // know how big the first one is so we don't know where this |
| 447 | // one starts. |
| 448 | frame = add_backtrace_entry(state->gregs[R_LR], backtrace, |
| 449 | ignore_depth, max_depth, &ignored_frames, &returned_frames); |
| 450 | } |
| 451 | return returned_frames; |
| 452 | } |
| 453 | |
| 454 | // Ok, continue from the LR. |
| 455 | set_reg(state, R_PC, state->gregs[R_LR]); |
| 456 | } |
| 457 | |
| 458 | while (handler && returned_frames < max_depth) { |
| 459 | backtrace_frame_t* frame = add_backtrace_entry(state->gregs[R_PC], backtrace, |
| 460 | ignore_depth, max_depth, &ignored_frames, &returned_frames); |
| 461 | if (frame) { |
| 462 | frame->stack_top = state->gregs[R_SP]; |
| 463 | } |
| 464 | |
| 465 | byte_stream_t stream; |
| 466 | stream.ptr = handler; |
| 467 | uint8_t pr; |
| 468 | if (!try_next_byte(tid, &stream, &pr)) { |
| 469 | break; |
| 470 | } |
| 471 | if ((pr & 0xf0) != 0x80) { |
| 472 | // The first word is a place-relative pointer to a generic personality |
| 473 | // routine function. We don't support invoking such functions, so stop here. |
| 474 | break; |
| 475 | } |
| 476 | |
| 477 | // The first byte indicates the personality routine to execute. |
| 478 | // Following bytes provide instructions to the personality routine. |
| 479 | if (!execute_personality_routine(tid, state, &stream, pr & 0x0f)) { |
| 480 | break; |
| 481 | } |
| 482 | if (frame && state->gregs[R_SP] > frame->stack_top) { |
| 483 | frame->stack_size = state->gregs[R_SP] - frame->stack_top; |
| 484 | } |
| 485 | |
| 486 | handler = get_exception_handler(context, tid, state->gregs[R_PC]); |
| 487 | } |
| 488 | return returned_frames; |
| 489 | } |
| 490 | |
| 491 | ssize_t unwind_backtrace_signal_arch(siginfo_t* siginfo, void* sigcontext, |
| 492 | backtrace_frame_t* backtrace, size_t ignore_depth, size_t max_depth) { |
| 493 | const ucontext_t* uc = (const ucontext_t*)sigcontext; |
| 494 | |
| 495 | unwind_state_t state; |
| 496 | for (int i = 0; i < 16; i++) { |
| 497 | state.gregs[i] = uc->uc_mcontext.gregs[i]; |
| 498 | } |
| 499 | |
| 500 | return unwind_backtrace_common(-1, NULL, &state, backtrace, ignore_depth, max_depth); |
| 501 | } |
| 502 | |
| 503 | ssize_t unwind_backtrace_ptrace_arch(pid_t tid, const ptrace_context_t* context, |
| 504 | backtrace_frame_t* backtrace, size_t ignore_depth, size_t max_depth) { |
| 505 | struct pt_regs regs; |
| 506 | if (ptrace(PTRACE_GETREGS, tid, 0, ®s)) { |
| 507 | return -1; |
| 508 | } |
| 509 | |
| 510 | unwind_state_t state; |
| 511 | for (int i = 0; i < 16; i++) { |
| 512 | state.gregs[i] = regs.uregs[i]; |
| 513 | } |
| 514 | |
| 515 | return unwind_backtrace_common(tid, context, &state, backtrace, ignore_depth, max_depth); |
| 516 | } |