ostd/
panic.rs

1// SPDX-License-Identifier: MPL-2.0
2
3//! Panic support.
4
5use crate::early_println;
6
7extern crate cfg_if;
8extern crate gimli;
9
10/// The default panic handler for OSTD based kernels.
11///
12/// The user can override it by defining their own panic handler with the macro
13/// `#[ostd::panic_handler]`.
14#[linkage = "weak"]
15// SAFETY: The name does not collide with other symbols.
16#[unsafe(no_mangle)]
17pub fn __ostd_panic_handler(info: &core::panic::PanicInfo) -> ! {
18    let _irq_guard = crate::irq::disable_local();
19
20    crate::cpu_local_cell! {
21        static IN_PANIC: bool = false;
22    }
23
24    if IN_PANIC.load() {
25        early_println!("The panic handler panicked {:#?}", info);
26        abort();
27    }
28
29    IN_PANIC.store(true);
30
31    early_println!("Non-resettable panic! {:#?}", info);
32
33    print_stack_trace();
34    abort();
35}
36
37/// Aborts the system.
38///
39/// This function will first attempt to power off the system. If that fails, it will halt all CPUs.
40pub fn abort() -> ! {
41    // TODO: The main purpose of powering off here is to allow QEMU to exit. Otherwise, the CI may
42    // freeze after panicking. However, this is unnecessary and may prevent debugging on a real
43    // machine (i.e., the message will disappear afterward).
44    crate::power::poweroff(crate::power::ExitCode::Failure);
45}
46
47#[cfg(not(target_arch = "loongarch64"))]
48pub use unwinding::panic::{begin_panic, catch_unwind};
49
50/// Prints the stack trace of the current thread to the console.
51///
52/// The printing procedure is protected by a spin lock to prevent interleaving.
53#[cfg(not(target_arch = "loongarch64"))]
54pub fn print_stack_trace() {
55    use core::ffi::c_void;
56
57    use gimli::Register;
58    use unwinding::abi::{
59        _Unwind_Backtrace, _Unwind_FindEnclosingFunction, _Unwind_GetGR, _Unwind_GetIP,
60        UnwindContext, UnwindReasonCode,
61    };
62
63    use crate::{early_print, sync::SpinLock};
64
65    /// We acquire a global lock to prevent the frames in the stack trace from
66    /// interleaving. The spin lock is used merely for its simplicity.
67    static BACKTRACE_PRINT_LOCK: SpinLock<()> = SpinLock::new(());
68    let _lock = BACKTRACE_PRINT_LOCK.lock();
69
70    early_println!("Printing stack trace:");
71
72    struct CallbackData {
73        counter: usize,
74    }
75    extern "C" fn callback(unwind_ctx: &UnwindContext<'_>, arg: *mut c_void) -> UnwindReasonCode {
76        let data = unsafe { &mut *(arg as *mut CallbackData) };
77        data.counter += 1;
78        let pc = _Unwind_GetIP(unwind_ctx);
79        if pc > 0 {
80            let fde_initial_address = _Unwind_FindEnclosingFunction(pc as *mut c_void) as usize;
81            early_println!(
82                "{:4}: fn {:#18x} - pc {:#18x} / registers:",
83                data.counter,
84                fde_initial_address,
85                pc,
86            );
87        }
88        // Print the first 8 general registers for any architecture. The register number follows
89        // the DWARF standard.
90        for i in 0..8u16 {
91            let reg_i = _Unwind_GetGR(unwind_ctx, i as i32);
92            cfg_if::cfg_if! {
93                if #[cfg(target_arch = "x86_64")] {
94                    let reg_name = gimli::X86_64::register_name(Register(i)).unwrap_or("unknown");
95                } else if #[cfg(target_arch = "riscv64")] {
96                    let reg_name = gimli::RiscV::register_name(Register(i)).unwrap_or("unknown");
97                } else if #[cfg(target_arch = "aarch64")] {
98                    let reg_name = gimli::AArch64::register_name(Register(i)).unwrap_or("unknown");
99                } else {
100                    let reg_name = "unknown";
101                }
102            }
103            if i.is_multiple_of(4) {
104                early_print!("\n    ");
105            }
106            early_print!(" {} {:#18x};", reg_name, reg_i);
107        }
108        early_print!("\n\n");
109        UnwindReasonCode::NO_REASON
110    }
111
112    let mut data = CallbackData { counter: 0 };
113    _Unwind_Backtrace(callback, &mut data as *mut _ as _);
114}
115
116/// Catches unwinding panics.
117#[cfg(target_arch = "loongarch64")]
118pub fn catch_unwind<R, F: FnOnce() -> R>(
119    f: F,
120) -> Result<R, alloc::boxed::Box<dyn core::any::Any + Send>> {
121    // TODO: Support unwinding in LoongArch.
122    Ok(f())
123}
124
125/// Begins panic handling
126#[cfg(target_arch = "loongarch64")]
127pub fn begin_panic<R>(_: alloc::boxed::Box<R>) {
128    // TODO: Support panic context in LoongArch.
129}
130
131/// Prints the stack trace of the current thread to the console.
132#[cfg(target_arch = "loongarch64")]
133pub fn print_stack_trace() {
134    // TODO: Support stack trace print in LoongArch.
135    early_println!("Printing stack trace:");
136}
ostd/panic.rs

ostd/
panic.rs
