122 lines
3.3 KiB
Rust
122 lines
3.3 KiB
Rust
mod context;
|
|
|
|
use riscv::register::{
|
|
mtvec::TrapMode,
|
|
stvec,
|
|
scause::{
|
|
self,
|
|
Trap,
|
|
Exception,
|
|
Interrupt,
|
|
},
|
|
stval,
|
|
sstatus,
|
|
sie,
|
|
};
|
|
use crate::syscall::syscall;
|
|
use crate::task::{
|
|
exit_current_and_run_next,
|
|
suspend_current_and_run_next,
|
|
current_user_token,
|
|
current_trap_cx,
|
|
};
|
|
use crate::timer::set_next_trigger;
|
|
use crate::config::{TRAP_CONTEXT, TRAMPOLINE};
|
|
|
|
global_asm!(include_str!("trap.S"));
|
|
|
|
pub fn init() {
|
|
set_kernel_trap_entry();
|
|
}
|
|
|
|
fn set_kernel_trap_entry() {
|
|
unsafe {
|
|
stvec::write(trap_from_kernel as usize, TrapMode::Direct);
|
|
}
|
|
}
|
|
|
|
fn set_user_trap_entry() {
|
|
unsafe {
|
|
stvec::write(TRAMPOLINE as usize, TrapMode::Direct);
|
|
}
|
|
}
|
|
|
|
#[allow(unused)]
|
|
pub fn enable_interrupt() {
|
|
unsafe { sstatus::set_sie(); }
|
|
}
|
|
|
|
pub fn enable_timer_interrupt() {
|
|
unsafe { sie::set_stimer(); }
|
|
}
|
|
|
|
#[no_mangle]
|
|
pub fn trap_handler() -> ! {
|
|
set_kernel_trap_entry();
|
|
let scause = scause::read();
|
|
let stval = stval::read();
|
|
match scause.cause() {
|
|
Trap::Exception(Exception::UserEnvCall) => {
|
|
// jump to next instruction anyway
|
|
let mut cx = current_trap_cx();
|
|
cx.sepc += 4;
|
|
// get system call return value
|
|
let result = syscall(cx.x[17], [cx.x[10], cx.x[11], cx.x[12]]);
|
|
// cx is changed during sys_exec, so we have to call it again
|
|
cx = current_trap_cx();
|
|
cx.x[10] = result as usize;
|
|
}
|
|
Trap::Exception(Exception::StoreFault) |
|
|
Trap::Exception(Exception::StorePageFault) |
|
|
Trap::Exception(Exception::InstructionFault) |
|
|
Trap::Exception(Exception::InstructionPageFault) |
|
|
Trap::Exception(Exception::LoadFault) |
|
|
Trap::Exception(Exception::LoadPageFault) => {
|
|
println!(
|
|
"[kernel] {:?} in application, bad addr = {:#x}, bad instruction = {:#x}, core dumped.",
|
|
scause.cause(),
|
|
stval,
|
|
current_trap_cx().sepc,
|
|
);
|
|
// page fault exit code
|
|
exit_current_and_run_next(-2);
|
|
}
|
|
Trap::Exception(Exception::IllegalInstruction) => {
|
|
println!("[kernel] IllegalInstruction in application, core dumped.");
|
|
// illegal instruction exit code
|
|
exit_current_and_run_next(-3);
|
|
}
|
|
Trap::Interrupt(Interrupt::SupervisorTimer) => {
|
|
set_next_trigger();
|
|
suspend_current_and_run_next();
|
|
}
|
|
_ => {
|
|
panic!("Unsupported trap {:?}, stval = {:#x}!", scause.cause(), stval);
|
|
}
|
|
}
|
|
trap_return();
|
|
}
|
|
|
|
#[no_mangle]
|
|
pub fn trap_return() -> ! {
|
|
set_user_trap_entry();
|
|
let trap_cx_ptr = TRAP_CONTEXT;
|
|
let user_satp = current_user_token();
|
|
extern "C" {
|
|
fn __alltraps();
|
|
fn __restore();
|
|
}
|
|
let restore_va = __restore as usize - __alltraps as usize + TRAMPOLINE;
|
|
unsafe {
|
|
llvm_asm!("fence.i" :::: "volatile");
|
|
llvm_asm!("jr $0" :: "r"(restore_va), "{a0}"(trap_cx_ptr), "{a1}"(user_satp) :: "volatile");
|
|
}
|
|
panic!("Unreachable in back_to_user!");
|
|
}
|
|
|
|
#[no_mangle]
|
|
pub fn trap_from_kernel() -> ! {
|
|
panic!("a trap {:?} from kernel!", scause::read().cause());
|
|
}
|
|
|
|
pub use context::{TrapContext};
|