111 lines
2.9 KiB
Rust
111 lines
2.9 KiB
Rust
mod context;
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use riscv::register::{
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mtvec::TrapMode,
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stvec,
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scause::{
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self,
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Trap,
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Exception,
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Interrupt,
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},
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stval,
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sstatus,
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sie,
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};
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use crate::syscall::syscall;
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use crate::task::{
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exit_current_and_run_next,
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suspend_current_and_run_next,
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current_user_token,
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current_trap_cx,
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};
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use crate::timer::set_next_trigger;
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use crate::config::{TRAP_CONTEXT, TRAMPOLINE};
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global_asm!(include_str!("trap.S"));
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pub fn init() {
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set_kernel_trap_entry();
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}
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fn set_kernel_trap_entry() {
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unsafe {
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stvec::write(trap_from_kernel as usize, TrapMode::Direct);
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}
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}
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fn set_user_trap_entry() {
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unsafe {
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stvec::write(TRAMPOLINE as usize, TrapMode::Direct);
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}
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}
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#[allow(unused)]
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pub fn enable_interrupt() {
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unsafe { sstatus::set_sie(); }
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}
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pub fn enable_timer_interrupt() {
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unsafe { sie::set_stimer(); }
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}
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#[no_mangle]
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pub fn trap_handler() -> ! {
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//println!("into trap_handler!");
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set_kernel_trap_entry();
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let cx = current_trap_cx();
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let scause = scause::read();
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let stval = stval::read();
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match scause.cause() {
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Trap::Exception(Exception::UserEnvCall) => {
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//println!("found UserEnvCall!");
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cx.sepc += 4;
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cx.x[10] = syscall(cx.x[17], [cx.x[10], cx.x[11], cx.x[12]]) as usize;
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}
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Trap::Exception(Exception::StoreFault) |
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Trap::Exception(Exception::StorePageFault) => {
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println!("[kernel] PageFault in application, bad addr = {:#x}, bad instruction = {:#x}, core dumped.", stval, cx.sepc);
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exit_current_and_run_next();
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}
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Trap::Exception(Exception::IllegalInstruction) => {
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println!("[kernel] IllegalInstruction in application, core dumped.");
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exit_current_and_run_next();
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}
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Trap::Interrupt(Interrupt::SupervisorTimer) => {
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set_next_trigger();
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suspend_current_and_run_next();
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}
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_ => {
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panic!("Unsupported trap {:?}, stval = {:#x}!", scause.cause(), stval);
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}
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}
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trap_return();
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}
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#[no_mangle]
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pub fn trap_return() -> ! {
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set_user_trap_entry();
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//println!("into trap_return");
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let trap_cx_ptr = TRAP_CONTEXT;
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let user_satp = current_user_token();
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//println!("trap_cx_ptr={:#x}, user_satp={:#x}", trap_cx_ptr, user_satp);
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extern "C" {
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fn __alltraps();
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fn __restore();
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}
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let restore_va = __restore as usize - __alltraps as usize + TRAMPOLINE;
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//println!("__alltraps={:#x},__restore={:#x}", __alltraps as usize, __restore as usize);
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//println!("restore_va={:#x}", restore_va);
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unsafe {
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llvm_asm!("jr $0" :: "r"(restore_va), "{a0}"(trap_cx_ptr), "{a1}"(user_satp) :: "volatile");
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}
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panic!("Unreachable in back_to_user!");
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}
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#[no_mangle]
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pub fn trap_from_kernel() -> ! {
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panic!("a trap from kernel!");
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}
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pub use context::{TrapContext};
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