Chris Dearman | 231e3c8 | 2012-08-10 17:06:20 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2012 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 mips |
| 19 | */ |
| 20 | |
| 21 | #define LOG_TAG "Corkscrew" |
| 22 | //#define LOG_NDEBUG 0 |
| 23 | |
| 24 | #include "../backtrace-arch.h" |
| 25 | #include "../backtrace-helper.h" |
| 26 | #include <corkscrew/ptrace.h> |
| 27 | |
| 28 | #include <stdlib.h> |
| 29 | #include <signal.h> |
| 30 | #include <stdbool.h> |
| 31 | #include <limits.h> |
| 32 | #include <errno.h> |
| 33 | #include <sys/ptrace.h> |
| 34 | #include <sys/exec_elf.h> |
| 35 | #include <cutils/log.h> |
| 36 | |
| 37 | /* For PTRACE_GETREGS */ |
| 38 | typedef struct { |
| 39 | /* FIXME: check this definition */ |
| 40 | uint64_t regs[32]; |
| 41 | uint64_t lo; |
| 42 | uint64_t hi; |
| 43 | uint64_t epc; |
| 44 | uint64_t badvaddr; |
| 45 | uint64_t status; |
| 46 | uint64_t cause; |
| 47 | } user_regs_struct; |
| 48 | |
| 49 | /* Machine context at the time a signal was raised. */ |
| 50 | typedef struct ucontext { |
| 51 | /* FIXME: use correct definition */ |
| 52 | uint32_t sp; |
| 53 | uint32_t ra; |
| 54 | uint32_t pc; |
| 55 | } ucontext_t; |
| 56 | |
| 57 | /* Unwind state. */ |
| 58 | typedef struct { |
| 59 | uint32_t sp; |
| 60 | uint32_t ra; |
| 61 | uint32_t pc; |
| 62 | } unwind_state_t; |
| 63 | |
| 64 | uintptr_t rewind_pc_arch(const memory_t* memory, uintptr_t pc) { |
| 65 | if (pc == 0) |
| 66 | return pc; |
| 67 | if ((pc & 1) == 0) |
| 68 | return pc-8; /* jal/bal/jalr + branch delay slot */ |
| 69 | return pc; |
| 70 | } |
| 71 | |
| 72 | static ssize_t unwind_backtrace_common(const memory_t* memory, |
| 73 | const map_info_t* map_info_list, |
| 74 | unwind_state_t* state, backtrace_frame_t* backtrace, |
| 75 | size_t ignore_depth, size_t max_depth) { |
| 76 | size_t ignored_frames = 0; |
| 77 | size_t returned_frames = 0; |
| 78 | |
| 79 | for (size_t index = 0; returned_frames < max_depth; index++) { |
| 80 | uintptr_t pc = index ? rewind_pc_arch(memory, state->pc) : state->pc; |
| 81 | backtrace_frame_t* frame; |
| 82 | uintptr_t addr; |
| 83 | int maxcheck = 1024; |
| 84 | int stack_size = 0, ra_offset = 0; |
| 85 | bool found_start = false; |
| 86 | |
| 87 | frame = add_backtrace_entry(pc, backtrace, ignore_depth, |
| 88 | max_depth, &ignored_frames, &returned_frames); |
| 89 | |
| 90 | if (frame) |
| 91 | frame->stack_top = state->sp; |
| 92 | |
Duane Sand | af3dd88 | 2012-09-24 09:24:45 -0700 | [diff] [blame] | 93 | ALOGV("#%d: frame=%p pc=%08x sp=%08x\n", |
| 94 | index, frame, frame->absolute_pc, frame->stack_top); |
Chris Dearman | 231e3c8 | 2012-08-10 17:06:20 -0700 | [diff] [blame] | 95 | |
| 96 | for (addr = state->pc; maxcheck-- > 0 && !found_start; addr -= 4) { |
| 97 | uint32_t op; |
| 98 | if (!try_get_word(memory, addr, &op)) |
| 99 | break; |
| 100 | |
| 101 | // ALOGV("@0x%08x: 0x%08x\n", addr, op); |
| 102 | switch (op & 0xffff0000) { |
| 103 | case 0x27bd0000: // addiu sp, imm |
| 104 | { |
| 105 | // looking for stack being decremented |
| 106 | int32_t immediate = ((((int)op) << 16) >> 16); |
| 107 | if (immediate < 0) { |
| 108 | stack_size = -immediate; |
| 109 | found_start = true; |
| 110 | ALOGV("@0x%08x: found stack adjustment=%d\n", addr, stack_size); |
| 111 | } |
| 112 | } |
| 113 | break; |
| 114 | case 0xafbf0000: // sw ra, imm(sp) |
| 115 | ra_offset = ((((int)op) << 16) >> 16); |
| 116 | ALOGV("@0x%08x: found ra offset=%d\n", addr, ra_offset); |
| 117 | break; |
| 118 | case 0x3c1c0000: // lui gp |
Duane Sand | af3dd88 | 2012-09-24 09:24:45 -0700 | [diff] [blame] | 119 | ALOGV("@0x%08x: found function boundary\n", addr); |
Chris Dearman | 231e3c8 | 2012-08-10 17:06:20 -0700 | [diff] [blame] | 120 | found_start = true; |
| 121 | break; |
| 122 | default: |
| 123 | break; |
| 124 | } |
| 125 | } |
| 126 | |
| 127 | if (ra_offset) { |
| 128 | uint32_t next_ra; |
| 129 | if (!try_get_word(memory, state->sp + ra_offset, &next_ra)) |
| 130 | break; |
| 131 | state->ra = next_ra; |
| 132 | ALOGV("New ra: 0x%08x\n", state->ra); |
| 133 | } |
| 134 | |
| 135 | if (stack_size) { |
| 136 | if (frame) |
| 137 | frame->stack_size = stack_size; |
| 138 | state->sp += stack_size; |
| 139 | ALOGV("New sp: 0x%08x\n", state->sp); |
| 140 | } |
| 141 | |
| 142 | if (state->pc == state->ra && stack_size == 0) |
| 143 | break; |
| 144 | |
| 145 | if (state->ra == 0) |
| 146 | break; |
| 147 | |
| 148 | state->pc = state->ra; |
| 149 | } |
| 150 | |
| 151 | ALOGV("returning %d frames\n", returned_frames); |
| 152 | |
| 153 | return returned_frames; |
| 154 | } |
| 155 | |
| 156 | ssize_t unwind_backtrace_signal_arch(siginfo_t* siginfo, void* sigcontext, |
| 157 | const map_info_t* map_info_list, |
| 158 | backtrace_frame_t* backtrace, size_t ignore_depth, size_t max_depth) { |
| 159 | const ucontext_t* uc = (const ucontext_t*)sigcontext; |
| 160 | |
| 161 | unwind_state_t state; |
| 162 | state.sp = uc->sp; |
| 163 | state.pc = uc->pc; |
| 164 | state.ra = uc->ra; |
| 165 | |
Duane Sand | af3dd88 | 2012-09-24 09:24:45 -0700 | [diff] [blame] | 166 | ALOGV("unwind_backtrace_signal_arch: " |
| 167 | "ignore_depth=%d max_depth=%d pc=0x%08x sp=0x%08x ra=0x%08x\n", |
Chris Dearman | 231e3c8 | 2012-08-10 17:06:20 -0700 | [diff] [blame] | 168 | ignore_depth, max_depth, state.pc, state.sp, state.ra); |
| 169 | |
| 170 | memory_t memory; |
| 171 | init_memory(&memory, map_info_list); |
| 172 | return unwind_backtrace_common(&memory, map_info_list, |
| 173 | &state, backtrace, ignore_depth, max_depth); |
| 174 | } |
| 175 | |
| 176 | ssize_t unwind_backtrace_ptrace_arch(pid_t tid, const ptrace_context_t* context, |
| 177 | backtrace_frame_t* backtrace, size_t ignore_depth, size_t max_depth) { |
| 178 | |
| 179 | user_regs_struct regs; |
| 180 | if (ptrace(PTRACE_GETREGS, tid, 0, ®s)) { |
| 181 | return -1; |
| 182 | } |
| 183 | |
| 184 | unwind_state_t state; |
| 185 | state.sp = regs.regs[29]; |
| 186 | state.ra = regs.regs[31]; |
| 187 | state.pc = regs.epc; |
| 188 | |
Duane Sand | af3dd88 | 2012-09-24 09:24:45 -0700 | [diff] [blame] | 189 | ALOGV("unwind_backtrace_ptrace_arch: " |
| 190 | "ignore_depth=%d max_depth=%d pc=0x%08x sp=0x%08x ra=0x%08x\n", |
Chris Dearman | 231e3c8 | 2012-08-10 17:06:20 -0700 | [diff] [blame] | 191 | ignore_depth, max_depth, state.pc, state.sp, state.ra); |
| 192 | |
| 193 | memory_t memory; |
| 194 | init_memory_ptrace(&memory, tid); |
| 195 | return unwind_backtrace_common(&memory, context->map_info_list, |
| 196 | &state, backtrace, ignore_depth, max_depth); |
| 197 | } |