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| 1 | +//! ksymbol |
| 2 | +
|
| 3 | +use alloc::string::{String, ToString}; |
| 4 | +use core::fmt::Debug; |
| 5 | +use rustc_demangle::demangle; |
| 6 | +use xmas_elf::{sections::SectionData::*, symbol_table::Entry}; |
| 7 | + |
| 8 | +core::arch::global_asm!(include_str!("ksymbol.S")); |
| 9 | + |
| 10 | +extern "C" { |
| 11 | + fn _start_ksymbol_elf(); |
| 12 | + fn _end_ksymbol_elf(); |
| 13 | + fn stext(); |
| 14 | + fn etext(); |
| 15 | +} |
| 16 | + |
| 17 | +/// KernelFuncEntry describes a kernel func, which is especially useful |
| 18 | +/// for dumping kernel symbols when backtracing the kernel stack. |
| 19 | +pub struct KernelFuncEntry { |
| 20 | + func_name: &'static str, |
| 21 | + start_addr: usize, |
| 22 | + func_size: usize, |
| 23 | +} |
| 24 | + |
| 25 | +impl KernelFuncEntry { |
| 26 | + /// Mangled func name of the kernel func. |
| 27 | + fn func_name(&self) -> &'static str { |
| 28 | + self.func_name |
| 29 | + } |
| 30 | + |
| 31 | + /// Entry address of the kernel func. |
| 32 | + fn start_addr(&self) -> usize { |
| 33 | + self.start_addr |
| 34 | + } |
| 35 | + |
| 36 | + /// Size in bytes of the kernel func. |
| 37 | + fn func_size(&self) -> usize { |
| 38 | + self.func_size |
| 39 | + } |
| 40 | +} |
| 41 | + |
| 42 | +impl Debug for KernelFuncEntry { |
| 43 | + fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result { |
| 44 | + write!( |
| 45 | + f, |
| 46 | + "KernelFuncEntry {{func_name: {}, entry_addr: {:#x}, func_size: {:#x} bytes}}", |
| 47 | + self.func_name(), |
| 48 | + self.start_addr(), |
| 49 | + self.func_size() |
| 50 | + ) |
| 51 | + } |
| 52 | +} |
| 53 | + |
| 54 | +/// Return the [KernelFuncEntry] of a kernel func by which the input addr is covered. |
| 55 | +/// |
| 56 | +/// If such kernel func cannot be found, return **None**. |
| 57 | +pub fn kernel_func_by_addr(addr: usize) -> Option<KernelFuncEntry> { |
| 58 | + // SAFETY: The build process of os can guarantee that the kernel symbol elf |
| 59 | + // can be found between _start_ksymbol_elf and _end_ksymbol_elf. See os/src/build.rs |
| 60 | + // for more details. |
| 61 | + let elf_data = unsafe { |
| 62 | + core::slice::from_raw_parts( |
| 63 | + _start_ksymbol_elf as *const u8, |
| 64 | + _end_ksymbol_elf as usize - _start_ksymbol_elf as usize, |
| 65 | + ) |
| 66 | + }; |
| 67 | + let elf = xmas_elf::ElfFile::new(elf_data).unwrap(); |
| 68 | + let symtab = elf.find_section_by_name(".symtab").unwrap(); |
| 69 | + let strtab = elf.find_section_by_name(".strtab").unwrap(); |
| 70 | + let strtab_offset = strtab.offset() as usize; |
| 71 | + let strtab_size = strtab.size() as usize; |
| 72 | + let strtab_data = &elf_data[strtab_offset..strtab_offset + strtab_size]; |
| 73 | + if let SymbolTable64(symtab_data) = symtab.get_data(&elf).unwrap() { |
| 74 | + symtab_data |
| 75 | + .iter() |
| 76 | + .find(|&entry| { |
| 77 | + if entry.size() == 0 { |
| 78 | + return false; |
| 79 | + } |
| 80 | + if entry.value() < stext as u64 || entry.value() > etext as u64 { |
| 81 | + return false; |
| 82 | + } |
| 83 | + let addr = addr as u64; |
| 84 | + addr >= entry.value() && addr < entry.value() + entry.size() |
| 85 | + }) |
| 86 | + .map(|entry| { |
| 87 | + let func_name_len = strtab_data[entry.name() as usize..] |
| 88 | + .iter() |
| 89 | + .enumerate() |
| 90 | + .find(|&pair| *pair.1 == 0) |
| 91 | + .map(|pair| pair.0) |
| 92 | + .unwrap(); |
| 93 | + // SAFETY: We can guarantee that this is a valid str due to the correctness of |
| 94 | + // the ELF format. |
| 95 | + let func_name = unsafe { |
| 96 | + core::str::from_raw_parts(&strtab_data[entry.name() as usize], func_name_len) |
| 97 | + }; |
| 98 | + KernelFuncEntry { |
| 99 | + func_name, |
| 100 | + start_addr: entry.value() as usize, |
| 101 | + func_size: entry.size() as usize, |
| 102 | + } |
| 103 | + }) |
| 104 | + } else { |
| 105 | + None |
| 106 | + } |
| 107 | +} |
| 108 | + |
| 109 | +/// Return demangled func name as a String of a mangled func name. |
| 110 | +pub fn demangled_func_name(func_name: &str) -> String { |
| 111 | + demangle(func_name).to_string() |
| 112 | +} |
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