add condvar in kernel and app

os/src/sync/condvar.rs

@@ -0,0 +1,39 @@
+use alloc::{sync::Arc, collections::VecDeque};
+use crate::task::{add_task, TaskControlBlock, current_task, block_current_and_run_next};
+use crate::sync::{Mutex, UPSafeCell};
+
+pub struct Condvar {
+    pub inner: UPSafeCell<CondvarInner>,
+}
+
+pub struct CondvarInner {
+    pub wait_queue: VecDeque<Arc<TaskControlBlock>>,
+}
+
+impl Condvar {
+    pub fn new() -> Self {
+        Self {
+            inner: unsafe { UPSafeCell::new(
+                CondvarInner {
+                    wait_queue: VecDeque::new(),
+                }
+            )},
+        }
+    }
+
+    pub fn signal(&self) {
+        let mut inner = self.inner.exclusive_access();
+        if let Some(task) = inner.wait_queue.pop_front() {
+            add_task(task);
+        }
+    }
+
+    pub fn wait(&self, mutex:Arc<dyn Mutex>) {
+        mutex.unlock();
+        let mut inner = self.inner.exclusive_access();
+        inner.wait_queue.push_back(current_task().unwrap());
+        drop(inner);
+        block_current_and_run_next();
+        mutex.lock();
+    }
+}

os/src/sync/mod.rs

@@ -1,7 +1,9 @@
 mod up;
 mod mutex;
 mod semaphore;
+mod condvar;
 
 pub use up::UPSafeCell;
 pub use mutex::{Mutex, MutexSpin, MutexBlocking};
 pub use semaphore::Semaphore;
+pub use condvar::Condvar;

os/src/syscall/mod.rs

@@ -21,6 +21,9 @@ const SYSCALL_MUTEX_UNLOCK: usize = 1012;
 const SYSCALL_SEMAPHORE_CREATE: usize = 1020;
 const SYSCALL_SEMAPHORE_UP: usize = 1021;
 const SYSCALL_SEMAPHORE_DOWN: usize = 1022;
+const SYSCALL_CONDVAR_CREATE: usize = 1030;
+const SYSCALL_CONDVAR_SIGNAL: usize = 1031;
+const SYSCALL_CONDVAR_WAIT: usize = 1032;
 
 mod fs;
 mod process;
@@ -57,6 +60,9 @@ pub fn syscall(syscall_id: usize, args: [usize; 3]) -> isize {
         SYSCALL_SEMAPHORE_CREATE => sys_semaphore_create(args[0]),
         SYSCALL_SEMAPHORE_UP => sys_semaphore_up(args[0]),
         SYSCALL_SEMAPHORE_DOWN => sys_semaphore_down(args[0]),
+        SYSCALL_CONDVAR_CREATE => sys_condvar_create(args[0]),
+        SYSCALL_CONDVAR_SIGNAL => sys_condvar_signal(args[0]),
+        SYSCALL_CONDVAR_WAIT => sys_condvar_wait(args[0], args[1]),
         _ => panic!("Unsupported syscall_id: {}", syscall_id),
     }
 }

os/src/syscall/sync.rs

@@ -1,5 +1,5 @@
 use crate::task::{current_task, current_process, block_current_and_run_next};
-use crate::sync::{Mutex, MutexSpin, MutexBlocking, Semaphore};
+use crate::sync::{Mutex, MutexSpin, MutexBlocking, Semaphore, Condvar};
 use crate::timer::{get_time_ms, add_timer};
 use alloc::sync::Arc;
 
@@ -88,3 +88,41 @@ pub fn sys_semaphore_down(sem_id: usize) -> isize {
     sem.down();
     0
 }
+
+
+pub fn sys_condvar_create(_arg: usize) -> isize {
+    let process = current_process();
+    let mut process_inner = process.inner_exclusive_access();
+    let id = if let Some(id) = process_inner
+        .condvar_list
+        .iter()
+        .enumerate()
+        .find(|(_, item)| item.is_none())
+        .map(|(id, _)| id) {
+        process_inner.condvar_list[id] = Some(Arc::new(Condvar::new()));    
+        id
+    } else {
+        process_inner.condvar_list.push(Some(Arc::new(Condvar::new())));
+        process_inner.condvar_list.len() - 1
+    };
+    id as isize
+}
+
+pub fn sys_condvar_signal(condvar_id: usize) -> isize {
+    let process = current_process();
+    let process_inner = process.inner_exclusive_access();
+    let condvar = Arc::clone(process_inner.condvar_list[condvar_id].as_ref().unwrap());
+    drop(process_inner);
+    condvar.signal();
+    0
+}
+
+pub fn sys_condvar_wait(condvar_id: usize, mutex_id: usize) -> isize {
+    let process = current_process();
+    let process_inner = process.inner_exclusive_access();
+    let condvar = Arc::clone(process_inner.condvar_list[condvar_id].as_ref().unwrap());
+    let mutex = Arc::clone(process_inner.mutex_list[mutex_id].as_ref().unwrap());
+    drop(process_inner);
+    condvar.wait(mutex);
+    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, Mutex, Semaphore};
+use crate::sync::{UPSafeCell, Mutex, Semaphore, Condvar};
 use core::cell::RefMut;
 use super::id::RecycleAllocator;
 use super::TaskControlBlock;
@@ -34,6 +34,7 @@ pub struct ProcessControlBlockInner {
     pub task_res_allocator: RecycleAllocator,
     pub mutex_list: Vec<Option<Arc<dyn Mutex>>>,
     pub semaphore_list: Vec<Option<Arc<Semaphore>>>,
+    pub condvar_list:  Vec<Option<Arc<Condvar>>>,
 }
 
 impl ProcessControlBlockInner {
@@ -99,6 +100,7 @@ impl ProcessControlBlock {
                 task_res_allocator: RecycleAllocator::new(),
                 mutex_list: Vec::new(),
                 semaphore_list: Vec::new(),
+                condvar_list: Vec::new(),
             })}
         });
         // create a main thread, we should allocate ustack and trap_cx here
@@ -213,6 +215,7 @@ impl ProcessControlBlock {
                  task_res_allocator: RecycleAllocator::new(),
                  mutex_list: Vec::new(),
                  semaphore_list: Vec::new(),
+                 condvar_list: Vec::new(),
             })}
         });
         // add child

user/src/bin/test_condvar.rs

@@ -0,0 +1,56 @@
+#![no_std]
+#![no_main]
+
+#[macro_use]
+extern crate user_lib;
+
+extern crate alloc;
+
+use user_lib::{condvar_create, condvar_signal, condvar_wait, mutex_blocking_create, mutex_lock, mutex_unlock};
+use user_lib::{thread_create, waittid, sleep};
+use user_lib::exit;
+use alloc::vec::Vec;
+
+static mut A: usize = 0;
+
+const CONDVAR_ID: usize = 0;
+const MUTEX_ID: usize = 0;
+
+unsafe fn first() -> ! {
+    sleep(10);
+    println!("First work, Change A --> 1 and wakeup Second");
+    mutex_lock(MUTEX_ID);
+    A=1;
+    condvar_signal(CONDVAR_ID);
+    mutex_unlock(MUTEX_ID);
+    exit(0)
+}
+
+unsafe fn second() -> ! {
+    println!("Second want to continue,but need to wait A=1");
+    mutex_lock(MUTEX_ID);
+    while A==0 {
+        println!("Second: A is {}", A);
+        condvar_wait(CONDVAR_ID, MUTEX_ID);
+    }
+    mutex_unlock(MUTEX_ID);
+    println!("A is {}, Second can work now", A);
+    exit(0)
+}
+
+#[no_mangle]
+pub fn main() -> i32 {
+    // create condvar & mutex
+    assert_eq!(condvar_create() as usize, CONDVAR_ID);
+    assert_eq!(mutex_blocking_create() as usize, MUTEX_ID);
+    // create threads
+    let mut threads = Vec::new();
+    threads.push(thread_create(first as usize, 0));
+    threads.push(thread_create(second as usize, 0));
+    // wait for all threads to complete
+    for thread in threads.iter() {
+        waittid(*thread as usize);
+    }
+    println!("test_condvar passed!");
+    0
+}

user/src/lib.rs

@@ -6,16 +6,16 @@
 
 #[macro_use]
 pub mod console;
-mod syscall;
 mod lang_items;
+mod syscall;
 
 extern crate alloc;
 #[macro_use]
 extern crate bitflags;
 
-use syscall::*;
-use buddy_system_allocator::LockedHeap;
 use alloc::vec::Vec;
+use buddy_system_allocator::LockedHeap;
+use syscall::*;
 
 const USER_HEAP_SIZE: usize = 32768;
 
@@ -38,16 +38,16 @@ pub extern "C" fn _start(argc: usize, argv: usize) -> ! {
     }
     let mut v: Vec<&'static str> = Vec::new();
     for i in 0..argc {
-        let str_start = unsafe {
-            ((argv + i * core::mem::size_of::<usize>()) as *const usize).read_volatile()
-        };
-        let len = (0usize..).find(|i| unsafe {
-            ((str_start + *i) as *const u8).read_volatile() == 0
-        }).unwrap();
+        let str_start =
+            unsafe { ((argv + i * core::mem::size_of::<usize>()) as *const usize).read_volatile() };
+        let len = (0usize..)
+            .find(|i| unsafe { ((str_start + *i) as *const u8).read_volatile() == 0 })
+            .unwrap();
         v.push(
             core::str::from_utf8(unsafe {
                 core::slice::from_raw_parts(str_start as *const u8, len)
-            }).unwrap()
+            })
+            .unwrap(),
         );
     }
     exit(main(argc, v.as_slice()));
@@ -69,22 +69,48 @@ bitflags! {
     }
 }
 
-pub fn dup(fd: usize) -> isize { sys_dup(fd) }
-pub fn open(path: &str, flags: OpenFlags) -> isize { sys_open(path, flags.bits) }
-pub fn close(fd: usize) -> isize { sys_close(fd) }
-pub fn pipe(pipe_fd: &mut [usize]) -> isize { sys_pipe(pipe_fd) }
-pub fn read(fd: usize, buf: &mut [u8]) -> isize { sys_read(fd, buf) }
-pub fn write(fd: usize, buf: &[u8]) -> isize { sys_write(fd, buf) }
-pub fn exit(exit_code: i32) -> ! { sys_exit(exit_code); }
-pub fn yield_() -> isize { sys_yield() }
-pub fn get_time() -> isize { sys_get_time() }
-pub fn getpid() -> isize { sys_getpid() }
-pub fn fork() -> isize { sys_fork() }
-pub fn exec(path: &str, args: &[*const u8]) -> isize { sys_exec(path, args) }
+pub fn dup(fd: usize) -> isize {
+    sys_dup(fd)
+}
+pub fn open(path: &str, flags: OpenFlags) -> isize {
+    sys_open(path, flags.bits)
+}
+pub fn close(fd: usize) -> isize {
+    sys_close(fd)
+}
+pub fn pipe(pipe_fd: &mut [usize]) -> isize {
+    sys_pipe(pipe_fd)
+}
+pub fn read(fd: usize, buf: &mut [u8]) -> isize {
+    sys_read(fd, buf)
+}
+pub fn write(fd: usize, buf: &[u8]) -> isize {
+    sys_write(fd, buf)
+}
+pub fn exit(exit_code: i32) -> ! {
+    sys_exit(exit_code);
+}
+pub fn yield_() -> isize {
+    sys_yield()
+}
+pub fn get_time() -> isize {
+    sys_get_time()
+}
+pub fn getpid() -> isize {
+    sys_getpid()
+}
+pub fn fork() -> isize {
+    sys_fork()
+}
+pub fn exec(path: &str, args: &[*const u8]) -> isize {
+    sys_exec(path, args)
+}
 pub fn wait(exit_code: &mut i32) -> isize {
     loop {
         match sys_waitpid(-1, exit_code as *mut _) {
-            -2 => { yield_(); }
+            -2 => {
+                yield_();
+            }
             // -1 or a real pid
             exit_pid => return exit_pid,
         }
@@ -94,7 +120,9 @@ pub fn wait(exit_code: &mut i32) -> isize {
 pub fn waitpid(pid: usize, exit_code: &mut i32) -> isize {
     loop {
         match sys_waitpid(pid as isize, exit_code as *mut _) {
-            -2 => { yield_(); }
+            -2 => {
+                yield_();
+            }
             // -1 or a real pid
             exit_pid => return exit_pid,
         }
@@ -104,21 +132,35 @@ pub fn sleep(sleep_ms: usize) {
     sys_sleep(sleep_ms);
 }
 
-pub fn thread_create(entry: usize, arg: usize) -> isize { sys_thread_create(entry, arg) }
-pub fn gettid() -> isize { sys_gettid() }
+pub fn thread_create(entry: usize, arg: usize) -> isize {
+    sys_thread_create(entry, arg)
+}
+pub fn gettid() -> isize {
+    sys_gettid()
+}
 pub fn waittid(tid: usize) -> isize {
     loop {
         match sys_waittid(tid) {
-            -2 => { yield_(); }
+            -2 => {
+                yield_();
+            }
             exit_code => return exit_code,
         }
     }
 }
 
-pub fn mutex_create() -> isize { sys_mutex_create(false) }
-pub fn mutex_blocking_create() -> isize { sys_mutex_create(true) }
-pub fn mutex_lock(mutex_id: usize) { sys_mutex_lock(mutex_id); }
-pub fn mutex_unlock(mutex_id: usize) { sys_mutex_unlock(mutex_id); }
+pub fn mutex_create() -> isize {
+    sys_mutex_create(false)
+}
+pub fn mutex_blocking_create() -> isize {
+    sys_mutex_create(true)
+}
+pub fn mutex_lock(mutex_id: usize) {
+    sys_mutex_lock(mutex_id);
+}
+pub fn mutex_unlock(mutex_id: usize) {
+    sys_mutex_unlock(mutex_id);
+}
 pub fn semaphore_create(res_count: usize) -> isize {
     sys_semaphore_create(res_count)
 }
@@ -128,4 +170,12 @@ pub fn semaphore_up(sem_id: usize) {
 pub fn semaphore_down(sem_id: usize) {
     sys_semaphore_down(sem_id);
 }
-
+pub fn condvar_create() -> isize {
+    sys_condvar_create(0)
+}
+pub fn condvar_signal(condvar_id: usize) {
+    sys_condvar_signal(condvar_id);
+}
+pub fn condvar_wait(condvar_id: usize, mutex_id: usize) {
+    sys_condvar_wait(condvar_id, mutex_id);
+}

user/src/syscall.rs

@@ -21,6 +21,9 @@ const SYSCALL_MUTEX_UNLOCK: usize = 1012;
 const SYSCALL_SEMAPHORE_CREATE: usize = 1020;
 const SYSCALL_SEMAPHORE_UP: usize = 1021;
 const SYSCALL_SEMAPHORE_DOWN: usize = 1022;
+const SYSCALL_CONDVAR_CREATE: usize = 1030;
+const SYSCALL_CONDVAR_SIGNAL: usize = 1031;
+const SYSCALL_CONDVAR_WAIT: usize = 1032;
 
 fn syscall(id: usize, args: [usize; 3]) -> isize {
     let mut ret: isize;
@@ -128,3 +131,15 @@ pub fn sys_semaphore_up(sem_id: usize) -> isize {
 pub fn sys_semaphore_down(sem_id: usize) -> isize {
     syscall(SYSCALL_SEMAPHORE_DOWN, [sem_id, 0, 0])
 }
+
+pub fn sys_condvar_create(_arg: usize) -> isize {
+    syscall(SYSCALL_CONDVAR_CREATE, [_arg, 0, 0])
+}
+
+pub fn sys_condvar_signal(condvar_id: usize) -> isize {
+    syscall(SYSCALL_CONDVAR_SIGNAL, [condvar_id, 0, 0])
+}
+
+pub fn sys_condvar_wait(condvar_id: usize, mutex_id:usize) -> isize {
+    syscall(SYSCALL_CONDVAR_WAIT, [condvar_id, mutex_id, 0])
+}