rcore-tutorial/os/src/lang_items.rs

use core::panic::PanicInfo;
use core::arch::asm;
use crate::sbi::shutdown;
use crate::task::current_kstack_top;

#[panic_handler]
fn panic(info: &PanicInfo) -> ! {
    if let Some(location) = info.location() {
        println!("[kernel] Panicked at {}:{} {}", location.file(), location.line(), info.message().unwrap());
    } else {
        println!("[kernel] Panicked: {}", info.message().unwrap());
    }
    unsafe { backtrace(); }
    shutdown()
}

unsafe fn backtrace() {
    let mut fp: usize;
    let stop = current_kstack_top();
    asm!("mv {}, s0", out(reg) fp);
    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);
    }
    println!("---END   BACKTRACE---");
}