From 1bb4074e2f71145ec824f0dd8f99b278417a8112 Mon Sep 17 00:00:00 2001
From: Julien CLEMENT <julien.clement@epita.fr>
Date: Wed, 4 Jan 2023 21:45:22 +0100
Subject: [PATCH] add statefull scheduler and syscall routine

Signed-off-by: Julien CLEMENT <julien.clement@epita.fr>
---
 src/proc/scheduler/mod.rs | 32 +++++++++++++++++++++++++++++---
 src/proc/thread/mod.rs    |  7 +++++--
 src/syscalls/mod.rs       | 34 +++++++++++++++++++++++++++++-----
 src/syscalls/proc.rs      |  8 ++++----
 4 files changed, 67 insertions(+), 14 deletions(-)

diff --git a/src/proc/scheduler/mod.rs b/src/proc/scheduler/mod.rs
index f4d4991..7d09de8 100644
--- a/src/proc/scheduler/mod.rs
+++ b/src/proc/scheduler/mod.rs
@@ -1,3 +1,4 @@
+use crate::println;
 use crate::utils::mutex::AsyncMutex;
 
 use super::thread::{Thread, ThreadId};
@@ -77,6 +78,7 @@ impl Scheduler {
             started: true,
             rsp: 0,
             base_stack: 0,
+            is_blocked: false,
         };
         res.register(Arc::new(RefCell::new(k_thread)));
         res
@@ -86,10 +88,19 @@ impl Scheduler {
         while let Some(id) = self.thread_queue.next().await {
             if let Some(thread) = self.get_thread(id) {
                 // Thread still exists
-                unsafe {
-                    (&mut *thread.as_ptr()).run();
+                let blocked: bool;
+                {
+                    blocked = thread.borrow().is_blocked;
+                } // Drop thread borrow
+                if !blocked {
+                    unsafe {
+                        (&mut *thread.as_ptr()).run();
+                    }
+
+                    if !thread.borrow().is_blocked {
+                        self.thread_queue.register(id);
+                    }
                 }
-                self.thread_queue.register(id);
             }
         }
     }
@@ -104,6 +115,21 @@ impl Scheduler {
         }
     }
 
+    pub fn block(&mut self, id: ThreadId) {
+        if let Some(thread) = self.get_thread(id) {
+            thread.borrow_mut().is_blocked = true;
+            println!("Blocked thread {:?}", id);
+        }
+    }
+
+    pub fn unblock(&mut self, id: ThreadId) {
+        if let Some(thread) = self.get_thread(id) {
+            thread.borrow_mut().is_blocked = false;
+            self.thread_queue.register(id);
+            println!("Unblocked thread {:?}", id);
+        }
+    }
+
     pub fn exit(&mut self, id: ThreadId) {
         self.threads.remove(&id).unwrap().borrow().exit();
     }
diff --git a/src/proc/thread/mod.rs b/src/proc/thread/mod.rs
index 53fbdf7..23d777b 100644
--- a/src/proc/thread/mod.rs
+++ b/src/proc/thread/mod.rs
@@ -25,10 +25,10 @@ impl ThreadId {
     }
 }
 
-pub async fn resume_k_thread() {
+pub fn resume_k_thread() {
     let k_thread: *mut Thread;
     {
-        let mut scheduler = SCHEDULER.lock().await;
+        let mut scheduler = SCHEDULER.try_lock().unwrap();
         k_thread = scheduler.get_thread(K_THREAD_ID).unwrap().as_ptr();
     } // Drop scheduler mutex guard
 
@@ -40,6 +40,7 @@ pub async fn resume_k_thread() {
 pub fn routine() {
     println!("Routine executed");
     crate::syscalls::syscall_routine(crate::syscalls::EXIT_ID); // Call exit
+    println!("SHOULD NEVER BE DISPLAYED");
 }
 
 pub struct Thread {
@@ -48,6 +49,7 @@ pub struct Thread {
     pub started: bool,
     pub rsp: u64,
     pub base_stack: u64,
+    pub is_blocked: bool,
 }
 
 impl Thread {
@@ -60,6 +62,7 @@ impl Thread {
                 started: false,
                 rsp: stack_bottom + STACK_SIZE as u64,
                 base_stack: stack_bottom,
+                is_blocked: false
             }
         }
     }
diff --git a/src/syscalls/mod.rs b/src/syscalls/mod.rs
index be2b42a..b6b5f11 100644
--- a/src/syscalls/mod.rs
+++ b/src/syscalls/mod.rs
@@ -1,4 +1,6 @@
+use crate::println;
 use crate::proc::thread::{resume_k_thread, RUNNING_THREAD};
+use crate::proc::scheduler::SCHEDULER;
 use crate::task::executor::EXECUTOR;
 use crate::task::Task;
 
@@ -19,25 +21,47 @@ pub struct SyscallContext {
     thread_id: crate::proc::thread::ThreadId,
 }
 
-pub fn syscall_dispatcher(context: SyscallContextT) -> Task {
-    match context.borrow().id {
-        EXIT_ID => Task::new(proc::exit(context.clone())),
-        _ => Task::new(bad_syscall()),
+impl SyscallContext {
+    pub async fn run(&mut self) {
+        println!("Running async syscall runner");
+        self.dispatch().await;
+        println!("Syscall end, unblocking thread");
+        SCHEDULER.lock().await.unblock(self.thread_id);
+    }
+
+    pub async fn dispatch(&mut self) {
+        match self.id {
+            EXIT_ID => proc::exit(self).await,
+            _ => bad_syscall().await,
+        }
     }
 }
 
+
+async fn syscall_runner(context: SyscallContextT) {
+    context.borrow_mut().run().await;
+}
+
 pub fn syscall_routine(syscall_id: SyscallId) -> u64 {
+    println!("Running syscall");
     let context: SyscallContextT = Arc::new(RefCell::new(SyscallContext {
         id: syscall_id,
         res: 0,
         thread_id: *RUNNING_THREAD.try_lock().unwrap(),
     }));
     
+    println!("Spawning async syscall runner");
     EXECUTOR
         .try_lock()
         .unwrap()
-        .spawn(syscall_dispatcher(context.clone()));
+        .spawn(Task::new(syscall_runner(context.clone())));
 
+    println!("Blocking thread");
+    SCHEDULER
+        .try_lock()
+        .unwrap()
+        .block(context.borrow().thread_id);
+    println!("Returning to scheduler");
     resume_k_thread();
 
     let res = context.borrow().res;
diff --git a/src/syscalls/proc.rs b/src/syscalls/proc.rs
index d8c8f3b..4148585 100644
--- a/src/syscalls/proc.rs
+++ b/src/syscalls/proc.rs
@@ -1,10 +1,10 @@
 use crate::println;
 use crate::proc::scheduler::SCHEDULER;
 
-use super::SyscallContextT;
+use super::SyscallContext;
 
-pub async fn exit(context: SyscallContextT) {
-    println!("Exiting thread");
+pub async fn exit(context: &SyscallContext) {
+    println!("Running exit(2)");
     let mut scheduler = SCHEDULER.lock().await;
-    scheduler.exit(context.borrow().thread_id);
+    scheduler.exit(context.thread_id);
 }