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mod context;
use core::arch::{asm, global_asm};
use crate::config::{TRAMPOLINE, TRAP_CONTEXT};
use crate::mm::{MapPermission, PhysPageNum, VirtAddr, VirtPageNum};
use crate::syscall::syscall;
use crate::task::{
current_task, current_trap_cx, current_user_token, do_signal, exit_current_and_run_next,
suspend_current_and_run_next, Signals,
};
use crate::timer::set_next_trigger;
use riscv::register::{
mtvec::TrapMode,
scause::{self, Exception, Interrupt, Trap},
sie, stval, stvec,
};
global_asm!(include_str!("trap.S"));
extern "C" {
pub fn __alltraps();
pub fn __restore();
pub fn __call_sigreturn();
}
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);
}
}
pub fn enable_timer_interrupt() {
unsafe {
sie::set_stimer();
}
}
#[no_mangle]
pub fn trap_handler() -> ! {
set_kernel_trap_entry();
{
let task = current_task().unwrap();
let mut inner = task.acquire_inner_lock();
inner.update_process_times_enter_trap();
}
let scause = scause::read();
let stval = stval::read();
match scause.cause() {
Trap::Exception(Exception::UserEnvCall) => {
let mut cx = current_trap_cx();
cx.sepc += 4;
let result = syscall(
cx.x[17],
[cx.x[10], cx.x[11], cx.x[12], cx.x[13], cx.x[14], cx.x[15]],
);
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) => {
let task = current_task().unwrap();
let mut inner = task.acquire_inner_lock();
let addr = VirtAddr::from(stval);
log::debug!(
"[page_fault] pid: {}, type: {:?}",
task.pid.0,
scause.cause()
);
if inner.memory_set.do_page_fault(addr).is_err() {
inner.add_signal(Signals::SIGSEGV);
log::debug!("{:?}", inner.siginfo);
}
}
Trap::Exception(Exception::IllegalInstruction) => {
let task = current_task().unwrap();
let mut inner = task.acquire_inner_lock();
inner.add_signal(Signals::SIGILL);
}
Trap::Interrupt(Interrupt::SupervisorTimer) => {
set_next_trigger();
suspend_current_and_run_next();
}
_ => {
panic!(
"Unsupported trap {:?}, stval = {:#x}!",
scause.cause(),
stval
);
}
}
{
let task = current_task().unwrap();
let mut inner = task.acquire_inner_lock();
inner.update_process_times_leave_trap(scause.cause());
}
trap_return();
}
#[no_mangle]
pub fn trap_return() -> ! {
do_signal();
set_user_trap_entry();
let trap_cx_ptr = TRAP_CONTEXT;
let user_satp = current_user_token();
let restore_va = __restore as usize - __alltraps as usize + TRAMPOLINE;
unsafe {
asm!(
"fence.i",
"jr {restore_va}",
restore_va = in(reg) restore_va,
in("a0") trap_cx_ptr,
in("a1") user_satp,
options(noreturn)
);
}
}
#[no_mangle]
pub fn trap_from_kernel() -> ! {
println!("I will protect {:X}!", __call_sigreturn as usize);
panic!(
"a trap {:?} from kernel! bad addr = {:#x}, bad instruction = {:#x}",
scause::read().cause(),
stval::read(),
current_trap_cx().sepc
);
}
pub use context::TrapContext;