From 6f05feb55f20f213b18e3b2c6807030a3eb9d46b Mon Sep 17 00:00:00 2001
From: apio <blobs.trading@gmail.com>
Date: Wed, 7 Dec 2022 15:55:58 +0100
Subject: [PATCH] Add sleeping mechanism

---
 kernel/src/arch/CPU.h             |  4 +---
 kernel/src/arch/x86_64/Thread.cpp |  1 +
 kernel/src/main.cpp               | 29 ++++++++---------------------
 kernel/src/thread/Scheduler.cpp   | 19 +++++++++++++++++++
 kernel/src/thread/Scheduler.h     |  6 +++++-
 kernel/src/thread/Thread.h        |  1 +
 6 files changed, 35 insertions(+), 25 deletions(-)

diff --git a/kernel/src/arch/CPU.h b/kernel/src/arch/CPU.h
index 0021fea8..35159630 100644
--- a/kernel/src/arch/CPU.h
+++ b/kernel/src/arch/CPU.h
@@ -20,6 +20,4 @@ namespace CPU
     void enable_interrupts();
     void disable_interrupts();
     void wait_for_interrupt();
-}
-
-extern "C" void kernel_yield();
\ No newline at end of file
+}
\ No newline at end of file
diff --git a/kernel/src/arch/x86_64/Thread.cpp b/kernel/src/arch/x86_64/Thread.cpp
index 7eb3160e..4e1ffe86 100644
--- a/kernel/src/arch/x86_64/Thread.cpp
+++ b/kernel/src/arch/x86_64/Thread.cpp
@@ -31,6 +31,7 @@ void Thread::init_regs_kernel()
     memset(&regs, 0, sizeof(Registers));
     regs.cs = 0x08;
     regs.ss = 0x10;
+    regs.rflags = 1 << 9; // IF (Interrupt enable flag)
 }
 
 void Thread::set_arguments(u64 arg1, u64 arg2, u64 arg3, u64 arg4)
diff --git a/kernel/src/main.cpp b/kernel/src/main.cpp
index 7016296d..80c7accc 100644
--- a/kernel/src/main.cpp
+++ b/kernel/src/main.cpp
@@ -9,24 +9,17 @@
 #include <luna/Result.h>
 #include <luna/Units.h>
 
-void print_in_loop()
+void async_thread()
 {
     while (true)
     {
-        CPU::disable_interrupts();
-        Serial::printf("%lu", Scheduler::current()->id);
-        CPU::enable_interrupts();
-    }
-}
+        Thread* current = Scheduler::current();
+        kinfoln("Ticks: %lu, %lu user, %lu kernel, %lu idle", current->ticks, current->ticks_in_user,
+                current->ticks_in_kernel, Scheduler::idle()->ticks);
 
-void print_one_and_then_yield()
-{
-    while (true)
-    {
-        CPU::disable_interrupts();
-        Serial::printf("%lu", Scheduler::current()->id);
-        kernel_yield();
-        CPU::enable_interrupts();
+        CPU::wait_for_interrupt();
+
+        kernel_sleep(1000);
     }
 }
 
@@ -52,13 +45,7 @@ Result<void> init()
 
     Scheduler::init();
 
-    TRY(Scheduler::new_kernel_thread(print_in_loop));
-    TRY(Scheduler::new_kernel_thread(print_in_loop));
-    TRY(Scheduler::new_kernel_thread(print_in_loop));
-    TRY(Scheduler::new_kernel_thread(print_in_loop));
-    TRY(Scheduler::new_kernel_thread(print_in_loop));
-    TRY(Scheduler::new_kernel_thread(print_in_loop));
-    TRY(Scheduler::new_kernel_thread(print_one_and_then_yield));
+    TRY(Scheduler::new_kernel_thread(async_thread));
 
     CPU::platform_finish_init();
 
diff --git a/kernel/src/thread/Scheduler.cpp b/kernel/src/thread/Scheduler.cpp
index 9722afac..c6b7fe90 100644
--- a/kernel/src/thread/Scheduler.cpp
+++ b/kernel/src/thread/Scheduler.cpp
@@ -39,6 +39,11 @@ namespace Scheduler
         return g_current;
     }
 
+    Thread* idle()
+    {
+        return &g_idle;
+    }
+
     Result<void> kernel_thread_alloc_stack_and_append_impl(Thread* thread)
     {
         // FIXME: We will leak the thread if VM allocation or alloc_at fail.
@@ -146,6 +151,20 @@ namespace Scheduler
 
         g_current->ticks_left--;
 
+        g_threads.for_each([](Thread* thread) {
+            if (thread->state == ThreadState::Sleeping)
+            {
+                if (--thread->sleep_ticks_left == 0) thread->state = ThreadState::Runnable;
+            }
+        });
+
         if (!g_current->ticks_left) switch_task(regs);
     }
+}
+
+void kernel_sleep(u64 ms)
+{
+    g_current->sleep_ticks_left = ms;
+    g_current->state = ThreadState::Sleeping;
+    kernel_yield();
 }
\ No newline at end of file
diff --git a/kernel/src/thread/Scheduler.h b/kernel/src/thread/Scheduler.h
index 95b12451..57bb85ad 100644
--- a/kernel/src/thread/Scheduler.h
+++ b/kernel/src/thread/Scheduler.h
@@ -6,6 +6,7 @@ namespace Scheduler
     void init();
 
     Thread* current();
+    Thread* idle();
 
     Result<void> new_kernel_thread(u64 address);
     Result<void> new_kernel_thread(void (*func)(void));
@@ -16,4 +17,7 @@ namespace Scheduler
     void switch_task(Registers* regs);
 
     void invoke(Registers* regs);
-}
\ No newline at end of file
+}
+
+extern "C" void kernel_yield();
+void kernel_sleep(u64 ms);
\ No newline at end of file
diff --git a/kernel/src/thread/Thread.h b/kernel/src/thread/Thread.h
index d63e58c4..53e41a21 100644
--- a/kernel/src/thread/Thread.h
+++ b/kernel/src/thread/Thread.h
@@ -28,6 +28,7 @@ struct Thread : public DoublyLinkedListNode<Thread>
     u64 ticks_in_kernel = 0;
 
     u64 ticks_left;
+    u64 sleep_ticks_left;
 
     ThreadState state = ThreadState::Runnable;