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//! 中断服务例程
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//!
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//! # 中断处理总流程
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//!
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//! * 中断发生时，CPU首先完成以下工作：
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//! * 设置rsp的值（Ring3->0 或 DoubleFault，在TSS中设置）
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//! * 向栈中push一些值（Ring0时3项，Ring3时5项，某些中断还有错误码）
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//! * 跳转到`vector{i}`符号（位于`vector.asm`）
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//! * 进入中断服务例程后，完成以下工作：
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//! * `vector{i}`向栈中push空错误码（如CPU没有做）和中断号
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//! * 跳转到`__alltraps`（位于`trap.asm`）
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//! * `__alltraps`向栈中push全部寄存器的值
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//! * 调用`rust_trap`，并把此时的rsp传过来，也就是`TrapFrame`的指针
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//! * `rust_trap`完成以下工作：
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//! * 根据tf中的中断号，再次分发到具体的中断处理函数。
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//! 一些函数可能会调用switch()，切换到其它线程执行，在某一时刻再切换回来。
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//! * 如果需要，执行进程调度
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//! * `__alltraps`完成以下工作：
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//! * 检查tf中的cs段，如果是用户态，向TSS中设置下一次中断时重置rsp的值，使其指向该用户线程的内核栈
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//! * 从栈中pop全部寄存器的值，pop中断号和错误码
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//! * 执行iret，CPU从栈中pop一些值（若其中的CS是Ring0，3项，否则5项），重置rip和rsp（Ring3时）
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use super::TrapFrame;
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#[no_mangle]
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pub extern fn rust_trap(tf: &mut TrapFrame) {
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trace!("Interrupt: {:#x}", tf.trap_num);
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// Dispatch
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match tf.trap_num as u8 {
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T_BRKPT => breakpoint(),
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T_DBLFLT => double_fault(tf),
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T_PGFLT => page_fault(tf),
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T_IRQ0...64 => {
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let irq = tf.trap_num as u8 - T_IRQ0;
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match irq {
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IRQ_TIMER => timer(),
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IRQ_KBD => keyboard(),
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IRQ_COM1 => com1(),
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IRQ_COM2 => com2(),
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_ => panic!("Invalid IRQ number."),
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}
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#[cfg(feature = "use_apic")]
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use arch::driver::apic::ack;
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#[cfg(not(feature = "use_apic"))]
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use arch::driver::pic::ack;
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ack(irq);
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}
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T_SWITCH_TOK => to_kernel(tf),
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T_SWITCH_TOU => to_user(tf),
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T_SYSCALL => syscall(tf),
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T_SYSCALL32 => syscall32(tf),
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T_DIVIDE | T_GPFLT | T_ILLOP => error(tf),
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_ => panic!("Unhandled interrupt {:x}", tf.trap_num),
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}
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use process::PROCESSOR;
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PROCESSOR.try().unwrap().lock().schedule();
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}
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fn breakpoint() {
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error!("\nEXCEPTION: Breakpoint");
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}
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fn double_fault(tf: &TrapFrame) {
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error!("\nEXCEPTION: Double Fault\n{:#x?}", tf);
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loop {}
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}
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fn page_fault(tf: &mut TrapFrame) {
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use x86_64::registers::control_regs::cr2;
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let addr = cr2().0;
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error!("\nEXCEPTION: Page Fault @ {:#x}, code: {:#x}", addr, tf.error_code);
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use memory::page_fault_handler;
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if page_fault_handler(addr) {
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return;
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}
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error(tf);
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}
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use super::consts::*;
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fn keyboard() {
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use arch::driver::keyboard;
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info!("\nInterupt: Keyboard");
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let c = keyboard::get();
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info!("Key = '{}' {}", c as u8 as char, c);
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}
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fn com1() {
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use arch::driver::serial::COM1;
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info!("\nInterupt: COM1");
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COM1.lock().receive();
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}
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fn com2() {
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use arch::driver::serial::COM2;
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info!("\nInterupt: COM2");
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COM2.lock().receive();
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}
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fn timer() {
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use process::PROCESSOR;
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let mut processor = PROCESSOR.try().unwrap().lock();
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processor.tick();
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}
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fn to_user(tf: &mut TrapFrame) {
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use arch::gdt;
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info!("\nInterupt: To User");
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tf.cs = gdt::UCODE_SELECTOR.0 as usize;
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tf.ss = gdt::UDATA_SELECTOR.0 as usize;
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tf.rflags |= 3 << 12; // 设置EFLAG的I/O特权位，使得在用户态可使用in/out指令
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}
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fn to_kernel(tf: &mut TrapFrame) {
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use arch::gdt;
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info!("\nInterupt: To Kernel");
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tf.cs = gdt::KCODE_SELECTOR.0 as usize;
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tf.ss = gdt::KDATA_SELECTOR.0 as usize;
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}
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fn syscall(tf: &mut TrapFrame) {
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info!("\nInterupt: Syscall {:#x?}", tf.rax);
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use syscall::syscall;
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let ret = syscall(tf, false);
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tf.rax = ret as usize;
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}
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fn syscall32(tf: &mut TrapFrame) {
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// info!("\nInterupt: Syscall {:#x?}", tf.rax);
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use syscall::syscall;
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let ret = syscall(tf, true);
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tf.rax = ret as usize;
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}
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fn error(tf: &TrapFrame) {
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use process::PROCESSOR;
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if let Some(processor) = PROCESSOR.try() {
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let mut processor = processor.lock();
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let pid = processor.current_pid();
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error!("Process {} error:\n{:#x?}", pid, tf);
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processor.exit(pid, 0x100); // TODO: Exit code for error
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} else {
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error!("Exception {:#x} when processor not inited\n{:#x?}", tf.trap_num, tf);
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loop {}
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}
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}
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#[no_mangle]
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pub extern fn set_return_rsp(tf: &TrapFrame) {
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use arch::gdt::Cpu;
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use core::mem::size_of;
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if tf.cs & 0x3 == 3 {
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Cpu::current().set_ring0_rsp(tf as *const _ as usize + size_of::<TrapFrame>());
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}
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}
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