Kernel/HLE: Use a mutex to synchronize access to the HLE kernel state between the cpu thread and any other possible threads that might touch the kernel (network thread, etc).

This mutex is acquired in SVC::CallSVC, ie, as soon as the guest application enters the HLE kernel, and should be acquired by the aforementioned threads before modifying kernel structures.

5 files changed, 38 insertions, 3 deletions

diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index 360f407f3..14027e182 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -60,6 +60,7 @@ set(SRCS
             hle/kernel/timer.cpp
             hle/kernel/vm_manager.cpp
             hle/kernel/wait_object.cpp
+            hle/lock.cpp
             hle/romfs.cpp
             hle/service/ac/ac.cpp
             hle/service/ac/ac_i.cpp
@@ -258,6 +259,7 @@ set(HEADERS
             hle/kernel/timer.h
             hle/kernel/vm_manager.h
             hle/kernel/wait_object.h
+            hle/lock.h
             hle/result.h
             hle/romfs.h
             hle/service/ac/ac.h
diff --git a/src/core/hle/kernel/kernel.h b/src/core/hle/kernel/kernel.h
index 9cf288b08..255cda359 100644
--- a/src/core/hle/kernel/kernel.h
+++ b/src/core/hle/kernel/kernel.h
@@ -129,4 +129,4 @@ void Init(u32 system_mode);
 /// Shutdown the kernel
 void Shutdown();
 
-} // namespace
+} // namespace Kernel
diff --git a/src/core/hle/lock.cpp b/src/core/hle/lock.cpp
new file mode 100644
index 000000000..082f689c8
--- /dev/null
+++ b/src/core/hle/lock.cpp
@@ -0,0 +1,11 @@
+// Copyright 2017 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <core/hle/lock.h>
+
+namespace HLE {
+std::mutex g_hle_lock;
+}
diff --git a/src/core/hle/lock.h b/src/core/hle/lock.h
new file mode 100644
index 000000000..8265621e1
--- /dev/null
+++ b/src/core/hle/lock.h
@@ -0,0 +1,18 @@
+// Copyright 2017 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <mutex>
+
+namespace HLE {
+/*
+ * Synchronizes access to the internal HLE kernel structures, it is acquired when a guest
+ * application thread performs a syscall. It should be acquired by any host threads that read or
+ * modify the HLE kernel state. Note: Any operation that directly or indirectly reads from or writes
+ * to the emulated memory is not protected by this mutex, and should be avoided in any threads other
+ * than the CPU thread.
+ */
+extern std::mutex g_hle_lock;
+} // namespace HLE
diff --git a/src/core/hle/svc.cpp b/src/core/hle/svc.cpp
index e4b803046..b98938cb4 100644
--- a/src/core/hle/svc.cpp
+++ b/src/core/hle/svc.cpp
@@ -31,6 +31,7 @@
 #include "core/hle/kernel/timer.h"
 #include "core/hle/kernel/vm_manager.h"
 #include "core/hle/kernel/wait_object.h"
+#include "core/hle/lock.h"
 #include "core/hle/result.h"
 #include "core/hle/service/service.h"
 
@@ -1188,7 +1189,7 @@ struct FunctionDef {
     Func* func;
     const char* name;
 };
-}
+} // namespace
 
 static const FunctionDef SVC_Table[] = {
     {0x00, nullptr, "Unknown"},
@@ -1332,6 +1333,9 @@ MICROPROFILE_DEFINE(Kernel_SVC, "Kernel", "SVC", MP_RGB(70, 200, 70));
 void CallSVC(u32 immediate) {
     MICROPROFILE_SCOPE(Kernel_SVC);
 
+    // Lock the global kernel mutex when we enter the kernel HLE.
+    std::lock_guard<std::mutex> lock(HLE::g_hle_lock);
+
     const FunctionDef* info = GetSVCInfo(immediate);
     if (info) {
         if (info->func) {
@@ -1342,4 +1346,4 @@ void CallSVC(u32 immediate) {
     }
 }
 
-} // namespace
+} // namespace SVC