use mutex instead of static mut spinlocks

kernel/rustkernel/src/console/uart.rs

@@ -2,8 +2,7 @@
 #![allow(non_upper_case_globals)]
 
 use crate::{
-    console::consoleintr, proc::wakeup, queue::Queue, sync::mutex::Mutex,
+    console::consoleintr, proc::wakeup, queue::Queue, sync::mutex::Mutex, trap::InterruptBlocker,
-    trap::InterruptBlocker,
 };
 use core::ptr::addr_of;
 
@@ -111,7 +110,7 @@ impl Uart {
     pub fn write_byte(&self, b: u8) {
         let _ = InterruptBlocker::new();
 
-        if unsafe { crate::PANICKED } {
+        if *crate::PANICKED.lock_spinning() {
             loop {
                 core::hint::spin_loop();
             }
@@ -134,7 +133,7 @@ impl Uart {
     pub fn write_byte_buffered(&self, b: u8) {
         let mut buf = self.buffer.lock_spinning();
 
-        if unsafe { crate::PANICKED } {
+        if *crate::PANICKED.lock_spinning() {
             loop {
                 core::hint::spin_loop();
             }

kernel/rustkernel/src/lib.rs

@@ -21,13 +21,13 @@ pub mod sync;
 pub mod syscall;
 pub mod trap;
 
-use crate::proc::cpuid;
+use crate::{proc::cpuid, sync::mutex::Mutex};
 use core::ffi::{c_char, CStr};
 
 pub(crate) use crate::console::printf::{print, println};
 
 pub static mut STARTED: bool = false;
-pub static mut PANICKED: bool = false;
+pub static PANICKED: Mutex<bool> = Mutex::new(false);
 
 /// Maximum number of processes
 pub const NPROC: usize = 64;
@@ -65,7 +65,6 @@ pub unsafe extern "C" fn main() -> ! {
         mem::virtual_memory::kvminit();
         mem::virtual_memory::kvminithart();
         proc::procinit();
-        trap::trapinit();
         trap::trapinithart();
         riscv::plic::plicinit();
         riscv::plic::plicinithart();
@@ -113,7 +112,7 @@ fn panic_wrapper(panic_info: &core::panic::PanicInfo) -> ! {
     println!("╚═╝      ╚═════╝  ╚═════╝╚═╝  ╚═╝╚═╝╚═╝");
 
     unsafe {
-        crate::PANICKED = true;
+        *crate::PANICKED.lock_spinning() = true;
         // Quit QEMU for convenience.
         crate::syscall::Syscall::Shutdown.call();
     }

kernel/rustkernel/src/syscall.rs

@@ -1,15 +1,17 @@
 use crate::{
+    mem::virtual_memory::{copyin, copyinstr},
     println,
-    proc::{self, myproc, sleep_lock},
+    proc::{self, myproc},
-    riscv::{memlayout::QEMU_POWER, Pagetable},
+    riscv::memlayout::QEMU_POWER,
     string::strlen,
+    trap::CLOCK_TICKS,
+};
+use core::{
+    mem::size_of,
+    ptr::{addr_of, addr_of_mut},
 };
-use core::{mem::size_of, ptr::addr_of_mut};
 
 extern "C" {
-    fn copyin(pagetable: Pagetable, dst: *mut u8, srcva: u64, len: u64) -> i32;
-    fn copyinstr(pagetable: Pagetable, dst: *mut u8, srcva: u64, len: u64) -> i32;
-    // fn syscall();
     fn sys_pipe() -> u64;
     fn sys_read() -> u64;
     fn sys_exec() -> u64;
@@ -87,26 +89,22 @@ impl Syscall {
                 }
             }
             Syscall::Sleep => {
-                use crate::trap::{ticks, tickslock};
-
                 let mut n = 0i32;
                 argint(0, addr_of_mut!(n));
 
-                let _guard = tickslock.lock();
+                let mut ticks = CLOCK_TICKS.lock_spinning();
-                while ticks < ticks + n as u32 {
+
+                while *ticks < *ticks + n as usize {
                     if proc::killed(myproc()) > 0 {
-                        tickslock.unlock();
                         return -1i64 as u64;
                     }
-                    sleep_lock(addr_of_mut!(ticks).cast(), addr_of_mut!(tickslock).cast())
+                    // Sleep until the value changes.
+                    ticks.sleep(addr_of!(CLOCK_TICKS).cast_mut().cast());
                 }
                 0
             }
             // Returns how many clock tick interrupts have occured since start.
-            Syscall::Uptime => {
+            Syscall::Uptime => *CLOCK_TICKS.lock_spinning() as u64,
-                let _guard = crate::trap::tickslock.lock();
-                crate::trap::ticks as u64
-            }
             Syscall::Open => sys_open(),
             Syscall::Write => sys_write(),
             Syscall::Mknod => sys_mknod(),

kernel/rustkernel/src/trap.rs

@@ -2,10 +2,10 @@ use crate::{
     println,
     proc::{cpuid, exit, killed, mycpu, myproc, r#yield, setkilled, wakeup, ProcState},
     riscv::*,
-    sync::spinlock::Spinlock,
+    sync::mutex::Mutex,
     syscall::syscall,
 };
-use core::ptr::{addr_of, addr_of_mut};
+use core::ptr::addr_of;
 
 extern "C" {
     pub fn kernelvec();
@@ -19,15 +19,7 @@ extern "C" {
     pub static mut userret: [u8; 0];
 }
 
-#[no_mangle]
+pub static CLOCK_TICKS: Mutex<usize> = Mutex::new(0);
-pub static mut tickslock: Spinlock = Spinlock::new();
-#[no_mangle]
-pub static mut ticks: u32 = 0;
-
-#[no_mangle]
-pub unsafe extern "C" fn trapinit() {
-    tickslock = Spinlock::new();
-}
 
 /// Set up to take exceptions and traps while in the kernel.
 #[no_mangle]
@@ -37,9 +29,12 @@ pub unsafe extern "C" fn trapinithart() {
 
 #[no_mangle]
 pub unsafe extern "C" fn clockintr() {
-    let _guard = tickslock.lock();
+    let mut ticks = CLOCK_TICKS.lock_spinning();
-    ticks += 1;
+
-    wakeup(addr_of_mut!(ticks).cast());
+    *ticks += 1;
+    unsafe {
+        wakeup(addr_of!(CLOCK_TICKS).cast_mut().cast());
+    }
 }
 
 /// Check if it's an external interrupt or software interrupt and handle it.