Add MutexSpin and several syscalls.

os/src/sync/mod.rs

@@ -1,3 +1,5 @@
 mod up;
+mod mutex;
 
-pub use up::UPSafeCell;
+pub use up::UPSafeCell;
+pub use mutex::{Mutex, MutexSpin};

os/src/sync/mutex.rs

@@ -0,0 +1,40 @@
+use super::UPSafeCell;
+use crate::task::suspend_current_and_run_next;
+
+pub trait Mutex: Sync + Send {
+    fn lock(&self);
+    fn unlock(&self);
+}
+
+pub struct MutexSpin {
+    locked: UPSafeCell<bool>,
+}
+
+impl MutexSpin {
+    pub fn new() -> Self {
+        Self {
+            locked: unsafe { UPSafeCell::new(false) },
+        }
+    }
+}
+
+impl Mutex for MutexSpin {
+    fn lock(&self) {
+        loop {
+            let mut locked = self.locked.exclusive_access();
+            if *locked {
+                drop(locked);
+                suspend_current_and_run_next();
+                continue;
+            } else {
+                *locked = true;
+                return;
+            }
+        }
+    }
+
+    fn unlock(&self) {
+        let mut locked = self.locked.exclusive_access();
+        *locked = false;
+    }
+}

os/src/syscall/mod.rs

@@ -14,14 +14,19 @@ const SYSCALL_WAITPID: usize = 260;
 const SYSCALL_THREAD_CREATE: usize = 1000;
 const SYSCALL_GETTID: usize = 1001;
 const SYSCALL_WAITTID: usize = 1002;
+const SYSCALL_MUTEX_CREATE: usize = 1010;
+const SYSCALL_MUTEX_LOCK: usize = 1011;
+const SYSCALL_MUTEX_UNLOCK: usize = 1012;
 
 mod fs;
 mod process;
 mod thread;
+mod sync;
 
 use fs::*;
 use process::*;
 use thread::*;
+use sync::*;
 
 pub fn syscall(syscall_id: usize, args: [usize; 3]) -> isize {
     match syscall_id {
@@ -41,6 +46,9 @@ pub fn syscall(syscall_id: usize, args: [usize; 3]) -> isize {
         SYSCALL_THREAD_CREATE => sys_thread_create(args[0]),
         SYSCALL_GETTID => sys_gettid(),
         SYSCALL_WAITTID => sys_waittid(args[0]) as isize,
+        SYSCALL_MUTEX_CREATE => sys_mutex_create(),
+        SYSCALL_MUTEX_LOCK => sys_mutex_lock(args[0]),
+        SYSCALL_MUTEX_UNLOCK => sys_mutex_unlock(args[0]),
         _ => panic!("Unsupported syscall_id: {}", syscall_id),
     }
 }

os/src/syscall/sync.rs

@@ -0,0 +1,40 @@
+use crate::task::current_process;
+use crate::sync::MutexSpin;
+use alloc::sync::Arc;
+
+pub fn sys_mutex_create() -> isize {
+    let process = current_process();
+    let mut process_inner = process.inner_exclusive_access();
+    if let Some(id) = process_inner
+        .mutex_list
+        .iter()
+        .enumerate()
+        .find(|(_, item)| item.is_none())
+        .map(|(id, _)| id) {
+        process_inner.mutex_list[id] = Some(Arc::new(MutexSpin::new())); 
+        id as isize
+    } else {
+        process_inner.mutex_list.push(Some(Arc::new(MutexSpin::new())));
+        process_inner.mutex_list.len() as isize - 1
+    }
+}
+
+pub fn sys_mutex_lock(mutex_id: usize) -> isize {
+    let process = current_process();
+    let process_inner = process.inner_exclusive_access();
+    let mutex = Arc::clone(process_inner.mutex_list[mutex_id].as_ref().unwrap());
+    drop(process_inner);
+    drop(process);
+    mutex.lock();
+    0
+}
+
+pub fn sys_mutex_unlock(mutex_id: usize) -> isize {
+    let process = current_process();
+    let process_inner = process.inner_exclusive_access();
+    let mutex = Arc::clone(process_inner.mutex_list[mutex_id].as_ref().unwrap());
+    drop(process_inner);
+    drop(process);
+    mutex.unlock();
+    0
+}

os/src/task/process.rs

@@ -4,7 +4,7 @@ use crate::mm::{
     translated_refmut,
 };
 use crate::trap::{TrapContext, trap_handler};
-use crate::sync::UPSafeCell;
+use crate::sync::{UPSafeCell, Mutex};
 use core::cell::RefMut;
 use super::id::RecycleAllocator;
 use super::TaskControlBlock;
@@ -32,6 +32,7 @@ pub struct ProcessControlBlockInner {
     pub fd_table: Vec<Option<Arc<dyn File + Send + Sync>>>,
     pub tasks: Vec<Option<Arc<TaskControlBlock>>>,
     pub task_res_allocator: RecycleAllocator,
+    pub mutex_list: Vec<Option<Arc<dyn Mutex>>>,
 }
 
 impl ProcessControlBlockInner {
@@ -95,6 +96,7 @@ impl ProcessControlBlock {
                 ],
                 tasks: Vec::new(),
                 task_res_allocator: RecycleAllocator::new(),
+                mutex_list: Vec::new(),
             })}
         });
         // create a main thread, we should allocate ustack and trap_cx here
@@ -207,6 +209,7 @@ impl ProcessControlBlock {
                  fd_table: new_fd_table,
                  tasks: Vec::new(),
                  task_res_allocator: RecycleAllocator::new(),
+                 mutex_list: Vec::new(),
             })}
         });
         // add child