diff --git a/Kernel/KSyms.cpp b/Kernel/KSyms.cpp index 6e51adea9c..7ed4df99c7 100644 --- a/Kernel/KSyms.cpp +++ b/Kernel/KSyms.cpp @@ -110,7 +110,7 @@ UNMAP_AFTER_INIT static void load_kernel_symbols_from_data(Bytes buffer) g_kernel_symbols_available = true; } -NEVER_INLINE static void dump_backtrace_impl(FlatPtr base_pointer, bool use_ksyms, PrintToScreen print_to_screen) +NEVER_INLINE static void dump_backtrace_impl(FlatPtr frame_pointer, bool use_ksyms, PrintToScreen print_to_screen) { #define PRINT_LINE(fmtstr, ...) \ do { \ @@ -128,30 +128,79 @@ NEVER_INLINE static void dump_backtrace_impl(FlatPtr base_pointer, bool use_ksym FlatPtr address; KernelSymbol const* symbol { nullptr }; }; + + struct FrameRecord { + FlatPtr previous_frame_pointer; + FlatPtr return_address; + }; + + auto safe_memcpy_frame_record_from_stack = [](FlatPtr current_frame_pointer) -> ErrorOr { +#if ARCH(X86_64) || ARCH(AARCH64) + // x86_64/aarch64 frame record layout: + // rbp/fp+8: return address + // rbp/fp+0: previous base/frame pointer + + FlatPtr previous_frame_pointer_and_return_address[2]; + void* fault_at; + if (!safe_memcpy(previous_frame_pointer_and_return_address, bit_cast(current_frame_pointer), sizeof(previous_frame_pointer_and_return_address), fault_at)) + return EFAULT; + + return FrameRecord { + .previous_frame_pointer = previous_frame_pointer_and_return_address[0], + .return_address = previous_frame_pointer_and_return_address[1], + }; +#elif ARCH(RISCV64) + // riscv64 frame record layout: + // fp-8: return address + // fp-16: previous frame pointer + + FlatPtr previous_frame_pointer_and_return_address[2]; + void* fault_at; + if (!safe_memcpy(previous_frame_pointer_and_return_address, bit_cast(current_frame_pointer) - 2, sizeof(previous_frame_pointer_and_return_address), fault_at)) + return EFAULT; + + return FrameRecord { + .previous_frame_pointer = previous_frame_pointer_and_return_address[0], + .return_address = previous_frame_pointer_and_return_address[1], + }; +#else +# error Unknown architecture +#endif + }; + constexpr size_t max_recognized_symbol_count = 256; RecognizedSymbol recognized_symbols[max_recognized_symbol_count]; size_t recognized_symbol_count = 0; if (use_ksyms) { - FlatPtr copied_stack_ptr[2]; - for (FlatPtr* stack_ptr = (FlatPtr*)base_pointer; stack_ptr && recognized_symbol_count < max_recognized_symbol_count; stack_ptr = (FlatPtr*)copied_stack_ptr[0]) { - if ((FlatPtr)stack_ptr < kernel_mapping_base) + FlatPtr current_frame_pointer = frame_pointer; + + while (current_frame_pointer != 0 && recognized_symbol_count < max_recognized_symbol_count) { + if (current_frame_pointer < kernel_mapping_base) break; - void* fault_at; - if (!safe_memcpy(copied_stack_ptr, stack_ptr, sizeof(copied_stack_ptr), fault_at)) + auto frame_record_or_error = safe_memcpy_frame_record_from_stack(current_frame_pointer); + if (frame_record_or_error.is_error()) break; - FlatPtr retaddr = copied_stack_ptr[1]; - recognized_symbols[recognized_symbol_count++] = { retaddr, symbolicate_kernel_address(retaddr) }; + + auto frame_record = frame_record_or_error.release_value(); + + recognized_symbols[recognized_symbol_count++] = { frame_record.return_address, symbolicate_kernel_address(frame_record.return_address) }; + current_frame_pointer = frame_record.previous_frame_pointer; } } else { - void* fault_at; - FlatPtr copied_stack_ptr[2]; - FlatPtr* stack_ptr = (FlatPtr*)base_pointer; - while (stack_ptr && safe_memcpy(copied_stack_ptr, stack_ptr, sizeof(copied_stack_ptr), fault_at)) { - FlatPtr retaddr = copied_stack_ptr[1]; - PRINT_LINE("{:p} (next: {:p})", retaddr, stack_ptr ? (FlatPtr*)copied_stack_ptr[0] : 0); - stack_ptr = (FlatPtr*)copied_stack_ptr[0]; + FlatPtr current_frame_pointer = frame_pointer; + + while (current_frame_pointer != 0) { + auto frame_record_or_error = safe_memcpy_frame_record_from_stack(current_frame_pointer); + if (frame_record_or_error.is_error()) + break; + + auto frame_record = frame_record_or_error.release_value(); + + PRINT_LINE("{:p} (next: {:p})", frame_record.return_address, frame_record.previous_frame_pointer); + current_frame_pointer = frame_record.previous_frame_pointer; } + return; } VERIFY(recognized_symbol_count <= max_recognized_symbol_count);