Add a ProcessManager class to store Process objects.

Trying out a new method for exposing global objects directly via a
variable.

zion/CMakeLists.txt

@@ -14,6 +14,7 @@ add_executable(zion
   scheduler/context_switch.s
   scheduler/jump_user_space.s
   scheduler/process.cpp
+  scheduler/process_manager.cpp
   scheduler/scheduler.cpp
   scheduler/thread.cpp
   syscall/syscall.cpp

zion/loader/init_loader.cpp

@@ -4,7 +4,7 @@
 #include "debug/debug.h"
 #include "loader/elf_loader.h"
 #include "scheduler/process.h"
-#include "scheduler/scheduler.h"
+#include "scheduler/process_manager.h"
 
 namespace {
 
@@ -25,6 +25,6 @@ const limine_file& GetInitProgram() {
 void LoadInitProgram() {
   const limine_file& init_prog = GetInitProgram();
 
-  sched::InsertProcess(
+  gProcMan->InsertProcess(
       new Process(reinterpret_cast<uint64_t>(init_prog.address)));
 }

zion/scheduler/process_manager.cpp

@@ -0,0 +1,34 @@
+#include "scheduler/process_manager.h"
+
+ProcessManager* gProcMan = nullptr;
+
+void ProcessManager::Init() {
+  gProcMan = new ProcessManager();
+  gProcMan->InsertProcess(Process::RootProcess());
+}
+
+void ProcessManager::InsertProcess(const SharedPtr<Process>& proc) {
+  proc_list_.PushBack(proc);
+}
+
+Process& ProcessManager::FromId(uint64_t pid) {
+  auto iter = proc_list_.begin();
+  while (iter != proc_list_.end()) {
+    if (iter->id() == pid) {
+      return **iter;
+    }
+    ++iter;
+  }
+
+  panic("Searching for invalid process id");
+  return *((Process*)0);
+}
+
+void ProcessManager::DumpProcessStates() {
+  dbgln("Process States: %u", proc_list_.size());
+  auto iter = proc_list_.begin();
+  while (iter != proc_list_.end()) {
+    dbgln("%u: %u", iter->id(), iter->GetState());
+    ++iter;
+  }
+}

zion/scheduler/process_manager.h

@@ -0,0 +1,23 @@
+#pragma once
+
+#include "lib/linked_list.h"
+#include "lib/shared_ptr.h"
+#include "scheduler/process.h"
+
+class ProcessManager {
+ public:
+  // Initializes the ProcessManager
+  // and stores it in the global variable.
+  static void Init();
+
+  void InsertProcess(const SharedPtr<Process>& proc);
+  Process& FromId(uint64_t id);
+
+  void DumpProcessStates();
+
+ private:
+  // TODO: This should be a hashmap.
+  LinkedList<SharedPtr<Process>> proc_list_;
+};
+
+extern ProcessManager* gProcMan;

zion/scheduler/scheduler.cpp

@@ -2,36 +2,26 @@
 
 #include "debug/debug.h"
 #include "lib/linked_list.h"
+#include "scheduler/process_manager.h"
 
 namespace sched {
 namespace {
 
 extern "C" void context_switch(uint64_t* current_esp, uint64_t* next_esp);
 
-void DumpProcessStates(LinkedList<SharedPtr<Process>>& proc_list) {
-  dbgln("Process States: %u", proc_list.size());
-  auto iter = proc_list.begin();
-  while (iter != proc_list.end()) {
-    dbgln("%u: %u", iter->id(), iter->GetState());
-    ++iter;
-  }
-}
-
 class Scheduler {
  public:
   Scheduler() {
-    SharedPtr<Process> root = Process::RootProcess();
+    Process& root = gProcMan->FromId(0);
-    sleep_thread_ = root->GetThread(0);
+    sleep_thread_ = root.GetThread(0);
     // TODO: Implement a separate sleep thread?
     current_thread_ = sleep_thread_;
-    proc_list_.PushBack(root);
   }
   void Enable() { enabled_ = true; }
 
   Process& CurrentProcess() { return CurrentThread().process(); }
   Thread& CurrentThread() { return *current_thread_; }
 
-  void InsertProcess(Process* process) { proc_list_.PushBack(process); }
   void Enqueue(Thread* thread) { runnable_threads_.PushBack(thread); }
 
   void SwapToCurrent(Thread& prev) {
@@ -90,7 +80,7 @@ class Scheduler {
       if (runnable_threads_.size() == 0) {
         current_thread_ = sleep_thread_;
         dbgln("Sleeping");
-        DumpProcessStates(proc_list_);
+        gProcMan->DumpProcessStates();
       } else {
         // FIXME: Memory operation.
         current_thread_ = runnable_threads_.PopFront();
@@ -102,8 +92,6 @@ class Scheduler {
 
  private:
   bool enabled_ = false;
-  // TODO: move this to a separate process manager class.
-  LinkedList<SharedPtr<Process>> proc_list_;
 
   SharedPtr<Thread> current_thread_;
   LinkedList<SharedPtr<Thread>> runnable_threads_;
@@ -128,7 +116,6 @@ void EnableScheduler() { GetScheduler().Enable(); }
 void Preempt() { GetScheduler().Preempt(); }
 void Yield() { GetScheduler().Yield(); }
 
-void InsertProcess(Process* process) { GetScheduler().InsertProcess(process); }
 void EnqueueThread(Thread* thread) { GetScheduler().Enqueue(thread); }
 
 Process& CurrentProcess() { return GetScheduler().CurrentProcess(); }

zion/scheduler/scheduler.h

@@ -21,10 +21,6 @@ void Preempt();
 // Used when a thread blocks or exits.
 void Yield();
 
-// Scheduler will take ownership
-// of the created process.
-void InsertProcess(Process* proc);
-
 void EnqueueThread(Thread* thread);
 
 Process& CurrentProcess();

zion/zion.cpp

@@ -8,6 +8,7 @@
 #include "memory/kernel_heap.h"
 #include "memory/paging_util.h"
 #include "memory/physical_memory.h"
+#include "scheduler/process_manager.h"
 #include "scheduler/scheduler.h"
 #include "syscall/syscall.h"
 
@@ -28,6 +29,7 @@ extern "C" void zion() {
   InitSyscall();
 
   dbgln("[boot] Init scheduler.");
+  ProcessManager::Init();
   // Schedule every 50ms.
   SetFrequency(/* hertz= */ 20);
   sched::InitScheduler();