better backtrace

thanks rcore-os/rCore-Tutorial-v3#105 by Godones

Author: lythesia

.gitignore

@@ -5,3 +5,5 @@
 os/src/link_app.S
 os/src/linker.ld
 user/build
+
+os/src/trace/kernel_symbol.S

os/Cargo.lock

@@ -15,3 +15,7 @@ virtio-drivers = { git = "https://github.com/rcore-os/virtio-drivers", rev = "4e
 easy-fs = { path = "../easy-fs" }
 volatile = "0.3"
 lose-net-stack = { git = "https://github.com/yfblock/lose-net-stack", rev = "db42380" }
+tracer = { git = "https://github.com/os-module/rtrace" }
+
+[profile.release]
+debug = true

os/Cargo.toml

@@ -31,8 +31,8 @@ KERNEL_ENTRY_PA := 0x80200000
 OBJDUMP := rust-objdump --arch-name=riscv64
 OBJCOPY := rust-objcopy --binary-architecture=riscv64
 
-# Disassembly
-DISASM ?= -x
+# Disassembly (--disassemble-all)
+DISASM ?= -D
 
 # Run usertests or usershell
 TEST ?= 0
@@ -44,7 +44,7 @@ ifneq ($(strip $(USE_DISK)),)
 	FS_IMG := $(USE_DISK)
 endif
 
-build: env $(KERNEL_BIN) $(if $(strip $(USE_DISK)), ,fs-img)
+build: env stack_trace $(KERNEL_BIN) $(if $(strip $(USE_DISK)), ,fs-img)
 
 env:
 	(rustup target list | grep "riscv64gc-unknown-none-elf (installed)") || rustup target add $(TARGET)
@@ -61,11 +61,17 @@ fs-img: $(APPS)
 	@cd ../easy-fs-fuse && cargo run --release -- -s ../user/src/bin -t ../user/target/$(TARGET)/$(MODE)/
 
 $(APPS):
+# install trace_exe to generate elf symbol info
+stack_trace:
+	(cargo install --list | awk '/^\w/ {print $1}' | grep "cargo-binutils") || cargo install --git https://github.com/os-module/elfinfo
 
 kernel:
 	@echo Platform: $(BOARD)
+	@touch src/trace/kernel_symbol.S && rm src/trace/kernel_symbol.S
 	@cp src/linker-$(BOARD).ld src/linker.ld
 	@cargo build $(MODE_ARG)
+	@(nm -n ${KERNEL_ELF} | trace_exe > src/trace/kernel_symbol.S)
+	@cargo build $(MODE_ARG)
 	@rm src/linker.ld
 
 clean:

os/Makefile

@@ -1,6 +1,30 @@
+use std::{fs::File, io::Write, path::Path};
+
 const TARGET_PATH: &str = "../user/target/riscv64gc-unknown-none-elf/release/";
 
 fn main() {
     println!("cargo:rerun-if-changed=../user/src");
     println!("cargo:rerun-if-changed={}", TARGET_PATH);
+    println!("cargo:rerun-if-changed={}", "src");
+    let path = Path::new("src/trace/kernel_symbol.S");
+    if !path.exists() {
+        let mut f = File::create(path).unwrap();
+        writeln!(
+            f,
+            r#"
+    .section .rodata
+    .align 3
+    .globl symbol_num
+    .globl symbol_address
+    .globl symbol_index
+    .globl symbol_name
+symbol_num:
+    .quad {}
+symbol_address:
+symbol_index:
+symbol_name:"#,
+            0
+        )
+        .unwrap();
+    }
 }

os/build.rs

@@ -1,6 +1,8 @@
-use core::{arch::asm, panic::PanicInfo};
+use core::panic::PanicInfo;
 
-use crate::{sbi::shutdown, task::current_kstack_top};
+use tracer::{FramePointTracer, Tracer};
+
+use crate::sbi::shutdown;
 
 #[panic_handler]
 fn panic(info: &PanicInfo) -> ! {
@@ -14,23 +16,15 @@ fn panic(info: &PanicInfo) -> ! {
     } else {
         log::error!("Panicked: {}", info.message());
     }
-    unsafe {
-        backtrace();
-    }
+    backtrace();
     shutdown(true)
 }
 
-unsafe fn backtrace() {
-    let mut fp: usize;
-    let stop = current_kstack_top();
-    asm!("mv {}, s0", out(reg) fp);
+fn backtrace() {
     println!("---START BACKTRACE---");
-    for i in 0..10 {
-        if fp == stop {
-            break;
-        }
-        println!("#{}:ra={:#x}", i, *((fp - 8) as *const usize));
-        fp = *((fp - 16) as *const usize);
+    let tracer = FramePointTracer::new(crate::trace::Provider);
+    for v in tracer.trace() {
+        println!("[{:#x}] (+{:0>4x}) {}", v.func_addr, v.bias, v.func_name);
     }
     println!("---END   BACKTRACE---");
 }

os/src/lang_item.rs

@@ -25,6 +25,7 @@ mod sync;
 mod syscall;
 mod task;
 mod timer;
+mod trace;
 mod trap;
 
 use core::arch::global_asm;

os/src/main.rs

@@ -22,8 +22,8 @@ pub use manager::{add_task, pid2process, wakeup_task};
 pub use mem::*;
 pub use process::{FileMapping, MMapReserve, MapRange, ProcessControlBlock};
 pub use processor::{
-    current_kstack_top, current_process, current_task, current_trap_cx, current_trap_cx_user_va,
-    current_user_token, run_tasks, schedule, user_time_end, user_time_start,
+    current_process, current_task, current_trap_cx, current_trap_cx_user_va, current_user_token,
+    run_tasks, schedule, user_time_end, user_time_start,
 };
 pub use signal::{SignalFlags, MAX_SIG};
 pub use task::{TaskControlBlock, TaskStatus};

os/src/task/mod.rs

@@ -93,6 +93,7 @@ pub fn current_trap_cx_user_va() -> usize {
         .trap_cx_user_va()
 }
 
+#[allow(unused)]
 pub fn current_kstack_top() -> usize {
     if let Some(task) = current_task() {
         task.kstack.get_top()

os/src/task/processor.rs

@@ -0,0 +1,68 @@
+use core::arch::global_asm;
+
+use tracer::TracerProvider;
+
+global_asm!(include_str!("kernel_symbol.S"));
+
+extern "C" {
+    fn symbol_num();
+    fn symbol_address();
+    fn symbol_index();
+    fn symbol_name();
+}
+
+pub struct Provider;
+
+impl TracerProvider for Provider {
+    fn address2symbol(&self, addr: usize) -> Option<(usize, &'static str)> {
+        find_symbol_with_addr(addr)
+    }
+}
+
+pub fn find_symbol_with_addr(addr: usize) -> Option<(usize, &'static str)> {
+    // println!("find_sym_w/addr {:#x}", addr);
+    let symbol_num_addr = symbol_num as usize as *const usize;
+    // println!("symbol_num_addr {:#x}", symbol_num_addr as usize);
+    let symbol_num = unsafe { symbol_num_addr.read_volatile() };
+    // println!("num = {}", symbol_num);
+    if symbol_num == 0 {
+        return None;
+    }
+    let symbol_addr = symbol_address as usize as *const usize; // 符号地址存储区域
+    let addr_data = unsafe { core::slice::from_raw_parts(symbol_addr, symbol_num) };
+    // find the symbol with the nearest address
+    let mut index = -1isize;
+    for i in 0..symbol_num - 1 {
+        if addr >= addr_data[i] && addr < addr_data[i + 1] {
+            index = i as isize;
+            break;
+        }
+    }
+    if addr == addr_data[symbol_num - 1] {
+        index = (symbol_num - 1) as isize;
+    }
+    // println!("nearest addr to index = {}", index);
+    if index == -1 {
+        return None;
+    }
+    let index = index as usize;
+    let symbol_index = symbol_index as usize as *const usize; // 符号字符串的起始位置
+    let index_data = unsafe { core::slice::from_raw_parts(symbol_index, symbol_num) };
+    let symbol_name = symbol_name as usize as *const u8; // 符号字符串
+    let mut last = 0;
+    unsafe {
+        for i in index_data[index].. {
+            let c = symbol_name.add(i);
+            if *c == 0 {
+                last = i;
+                break;
+            }
+        }
+    }
+    let name = unsafe {
+        core::slice::from_raw_parts(symbol_name.add(index_data[index]), last - index_data[index])
+    };
+    let name = core::str::from_utf8(name).unwrap();
+    // println!("symbol = {}", name);
+    Some((addr_data[index], name))
+}