/* * Copyright (c) 2018-2020, Andreas Kling * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * 1. Redistributions of source code must retain the above copyright notice, this * list of conditions and the following disclaimer. * * 2. 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. * * 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 HOLDER 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. */ #include #include #include #include #include #include #include namespace Kernel { FlatPtr g_lowest_kernel_symbol_address = 0xffffffff; FlatPtr g_highest_kernel_symbol_address = 0; bool g_kernel_symbols_available = false; static KernelSymbol* s_symbols; static size_t s_symbol_count = 0; static u8 parse_hex_digit(char nibble) { if (nibble >= '0' && nibble <= '9') return nibble - '0'; VERIFY(nibble >= 'a' && nibble <= 'f'); return 10 + (nibble - 'a'); } FlatPtr address_for_kernel_symbol(const StringView& name) { for (size_t i = 0; i < s_symbol_count; ++i) { if (!strncmp(name.characters_without_null_termination(), s_symbols[i].name, name.length())) return s_symbols[i].address; } return 0; } const KernelSymbol* symbolicate_kernel_address(FlatPtr address) { if (address < g_lowest_kernel_symbol_address || address > g_highest_kernel_symbol_address) return nullptr; for (unsigned i = 0; i < s_symbol_count; ++i) { if (address < s_symbols[i + 1].address) return &s_symbols[i]; } return nullptr; } UNMAP_AFTER_INIT static void load_kernel_sybols_from_data(const KBuffer& buffer) { g_lowest_kernel_symbol_address = 0xffffffff; g_highest_kernel_symbol_address = 0; auto* bufptr = (const char*)buffer.data(); auto* start_of_name = bufptr; FlatPtr address = 0; for (size_t i = 0; i < 8; ++i) s_symbol_count = (s_symbol_count << 4) | parse_hex_digit(*(bufptr++)); s_symbols = static_cast(kmalloc_eternal(sizeof(KernelSymbol) * s_symbol_count)); ++bufptr; // skip newline klog() << "Loading kernel symbol table..."; size_t current_symbol_index = 0; while (bufptr < buffer.end_pointer()) { for (size_t i = 0; i < 8; ++i) address = (address << 4) | parse_hex_digit(*(bufptr++)); bufptr += 3; start_of_name = bufptr; while (*(++bufptr)) { if (*bufptr == '\n') { break; } } auto& ksym = s_symbols[current_symbol_index]; ksym.address = address; char* name = static_cast(kmalloc_eternal((bufptr - start_of_name) + 1)); memcpy(name, start_of_name, bufptr - start_of_name); name[bufptr - start_of_name] = '\0'; ksym.name = name; if (ksym.address < g_lowest_kernel_symbol_address) g_lowest_kernel_symbol_address = ksym.address; if (ksym.address > g_highest_kernel_symbol_address) g_highest_kernel_symbol_address = ksym.address; ++bufptr; ++current_symbol_index; } g_kernel_symbols_available = true; } NEVER_INLINE static void dump_backtrace_impl(FlatPtr base_pointer, bool use_ksyms) { SmapDisabler disabler; if (use_ksyms && !g_kernel_symbols_available) { Processor::halt(); return; } struct RecognizedSymbol { FlatPtr address; const KernelSymbol* symbol { nullptr }; }; 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 < 0xc0000000) break; void* fault_at; if (!safe_memcpy(copied_stack_ptr, stack_ptr, sizeof(copied_stack_ptr), fault_at)) break; FlatPtr retaddr = copied_stack_ptr[1]; recognized_symbols[recognized_symbol_count++] = { retaddr, symbolicate_kernel_address(retaddr) }; } } 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]; dbgln("{:p} (next: {:p})", retaddr, stack_ptr ? (FlatPtr*)copied_stack_ptr[0] : 0); stack_ptr = (FlatPtr*)copied_stack_ptr[0]; } return; } VERIFY(recognized_symbol_count <= max_recognized_symbol_count); for (size_t i = 0; i < recognized_symbol_count; ++i) { auto& symbol = recognized_symbols[i]; if (!symbol.address) break; if (!symbol.symbol) { dbgln("{:p}", symbol.address); continue; } size_t offset = symbol.address - symbol.symbol->address; if (symbol.symbol->address == g_highest_kernel_symbol_address && offset > 4096) dbgln("{:p}", symbol.address); else dbgln("{:p} {} +0x{:x}", symbol.address, demangle(symbol.symbol->name), offset); } } void dump_backtrace() { static bool in_dump_backtrace = false; if (in_dump_backtrace) return; TemporaryChange change(in_dump_backtrace, true); TemporaryChange disable_kmalloc_stacks(g_dump_kmalloc_stacks, false); FlatPtr ebp; asm volatile("movl %%ebp, %%eax" : "=a"(ebp)); dump_backtrace_impl(ebp, g_kernel_symbols_available); } UNMAP_AFTER_INIT void load_kernel_symbol_table() { auto result = VFS::the().open("/res/kernel.map", O_RDONLY, 0, VFS::the().root_custody()); if (!result.is_error()) { auto description = result.value(); auto buffer = description->read_entire_file(); if (!buffer.is_error()) load_kernel_sybols_from_data(*buffer.value()); } } }