[Zion] Add a mutex object with appropriate syscalls.

zion/lib/message_queue.cpp

@@ -54,16 +54,16 @@ z_err_t UnboundedMessageQueue::PushBack(uint64_t num_bytes, const void* bytes,
 z_err_t UnboundedMessageQueue::PopFront(uint64_t* num_bytes, void* bytes,
                                         uint64_t* num_caps, z_cap_t* caps,
                                         z_cap_t* reply_cap) {
-  mutex_.Lock();
+  mutex_->Lock();
   while (pending_messages_.empty()) {
     auto thread = gScheduler->CurrentThread();
     thread->SetState(Thread::BLOCKED);
     blocked_threads_.PushBack(thread);
-    mutex_.Unlock();
+    mutex_->Release();
     gScheduler->Yield();
-    mutex_.Lock();
+    mutex_->Lock();
   }
-  mutex_.Unlock();
+  mutex_->Release();
 
   MutexHolder lock(mutex_);
   auto next_msg = pending_messages_.PeekFront();
@@ -162,16 +162,16 @@ glcr::ErrorCode SingleMessageQueue::PushBack(uint64_t num_bytes,
 glcr::ErrorCode SingleMessageQueue::PopFront(uint64_t* num_bytes, void* bytes,
                                              uint64_t* num_caps, z_cap_t* caps,
                                              z_cap_t* reply_port) {
-  mutex_.Lock();
+  mutex_->Lock();
   while (!has_written_) {
     auto thread = gScheduler->CurrentThread();
     thread->SetState(Thread::BLOCKED);
     blocked_threads_.PushBack(thread);
-    mutex_.Unlock();
+    mutex_->Release();
     gScheduler->Yield();
-    mutex_.Lock();
+    mutex_->Lock();
   }
-  mutex_.Unlock();
+  mutex_->Release();
 
   MutexHolder lock(mutex_);
   if (has_read_) {

zion/lib/message_queue.h

@@ -8,7 +8,7 @@
 
 #include "capability/capability.h"
 #include "include/ztypes.h"
-#include "lib/mutex.h"
+#include "object/mutex.h"
 
 class MessageQueue {
  public:
@@ -23,7 +23,7 @@ class MessageQueue {
   virtual bool empty() = 0;
 
  protected:
-  Mutex mutex_{"message"};
+  glcr::RefPtr<Mutex> mutex_ = Mutex::Create();
   // FIXME: This maybe shouldn't be shared between classes since the
   // SingleMessageQueue should only ever have one blocked thread.
   glcr::IntrusiveList<Thread> blocked_threads_;

zion/lib/mutex.cpp

@@ -1,11 +0,0 @@
-#include "lib/mutex.h"
-
-#include "debug/debug.h"
-#include "scheduler/scheduler.h"
-
-void Mutex::Lock() {
-  while (__atomic_fetch_or(&lock_, 0x1, __ATOMIC_SEQ_CST) == 0x1) {
-    //    dbgln("Lock sleep: %s", name_);
-    gScheduler->Preempt();
-  }
-}

zion/lib/mutex.h

@@ -1,30 +0,0 @@
-#pragma once
-
-#include <stdint.h>
-
-class Mutex {
- public:
-  Mutex(const char* name) : name_(name) {}
-
-  // FIXME: Block thread on lock rather than "preempting"
-  void Lock();
-  void Unlock() { lock_ = false; }
-
- private:
-  const char* name_;
-
-  uint8_t lock_ = 0;
-};
-
-class MutexHolder {
- public:
-  MutexHolder(Mutex& mutex) : mutex_(mutex) { mutex_.Lock(); }
-
-  ~MutexHolder() { mutex_.Unlock(); }
-
-  MutexHolder(MutexHolder&) = delete;
-  MutexHolder(MutexHolder&&) = delete;
-
- private:
-  Mutex& mutex_;
-};