15 files changed, 129 insertions, 104 deletions

diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index 567d7454e..ab63f54de 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -108,6 +108,7 @@ set(HEADERS
             hle/kernel/kernel.h
             hle/kernel/mutex.h
             hle/kernel/semaphore.h
+            hle/kernel/session.h
             hle/kernel/shared_memory.h
             hle/kernel/thread.h
             hle/service/ac_u.h
diff --git a/src/core/hle/kernel/archive.cpp b/src/core/hle/kernel/archive.cpp
index ddc09e13b..0e3eb4564 100644
--- a/src/core/hle/kernel/archive.cpp
+++ b/src/core/hle/kernel/archive.cpp
@@ -2,6 +2,8 @@
 // Licensed under GPLv2
 // Refer to the license.txt file included.
 
+#include <map>
+
 #include "common/common_types.h"
 #include "common/file_util.h"
 #include "common/math_util.h"
@@ -10,8 +12,8 @@
 #include "core/file_sys/archive_sdmc.h"
 #include "core/file_sys/directory.h"
 #include "core/hle/kernel/archive.h"
+#include "core/hle/kernel/session.h"
 #include "core/hle/result.h"
-#include "core/hle/service/service.h"
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 // Kernel namespace
@@ -41,19 +43,15 @@ enum class DirectoryCommand : u32 {
     Close           = 0x08020000,
 };
 
-class Archive : public Object {
+class Archive : public Kernel::Session {
 public:
-    std::string GetTypeName() const override { return "Archive"; }
-    std::string GetName() const override { return name; }
-
-    static Kernel::HandleType GetStaticHandleType() { return HandleType::Archive; }
-    Kernel::HandleType GetHandleType() const override { return HandleType::Archive; }
+    std::string GetName() const override { return "Archive: " + name; }
 
     std::string name;           ///< Name of archive (optional)
     FileSys::Archive* backend;  ///< Archive backend interface
 
     ResultVal<bool> SyncRequest() override {
-        u32* cmd_buff = Service::GetCommandBuffer();
+        u32* cmd_buff = Kernel::GetCommandBuffer();
         FileCommand cmd = static_cast<FileCommand>(cmd_buff[0]);
 
         switch (cmd) {
@@ -102,7 +100,8 @@ public:
         default:
         {
             LOG_ERROR(Service_FS, "Unknown command=0x%08X", cmd);
-            return UnimplementedFunction(ErrorModule::FS);
+            cmd_buff[0] = UnimplementedFunction(ErrorModule::FS).raw;
+            return MakeResult<bool>(false);
         }
         }
         cmd_buff[1] = 0; // No error
@@ -110,19 +109,15 @@ public:
     }
 };
 
-class File : public Object {
+class File : public Kernel::Session {
 public:
-    std::string GetTypeName() const override { return "File"; }
-    std::string GetName() const override { return path.DebugStr(); }
-
-    static Kernel::HandleType GetStaticHandleType() { return HandleType::File; }
-    Kernel::HandleType GetHandleType() const override { return HandleType::File; }
+    std::string GetName() const override { return "Path: " + path.DebugStr(); }
 
     FileSys::Path path; ///< Path of the file
     std::unique_ptr<FileSys::File> backend; ///< File backend interface
 
     ResultVal<bool> SyncRequest() override {
-        u32* cmd_buff = Service::GetCommandBuffer();
+        u32* cmd_buff = Kernel::GetCommandBuffer();
         FileCommand cmd = static_cast<FileCommand>(cmd_buff[0]);
         switch (cmd) {
 
@@ -188,19 +183,15 @@ public:
     }
 };
 
-class Directory : public Object {
+class Directory : public Kernel::Session {
 public:
-    std::string GetTypeName() const override { return "Directory"; }
-    std::string GetName() const override { return path.DebugStr(); }
-
-    static Kernel::HandleType GetStaticHandleType() { return HandleType::Directory; }
-    Kernel::HandleType GetHandleType() const override { return HandleType::Directory; }
+    std::string GetName() const override { return "Directory: " + path.DebugStr(); }
 
     FileSys::Path path; ///< Path of the directory
     std::unique_ptr<FileSys::Directory> backend; ///< File backend interface
 
     ResultVal<bool> SyncRequest() override {
-        u32* cmd_buff = Service::GetCommandBuffer();
+        u32* cmd_buff = Kernel::GetCommandBuffer();
         DirectoryCommand cmd = static_cast<DirectoryCommand>(cmd_buff[0]);
         switch (cmd) {
 
@@ -230,7 +221,7 @@ public:
             LOG_ERROR(Service_FS, "Unknown command=0x%08X!", cmd);
             ResultCode error = UnimplementedFunction(ErrorModule::FS);
             cmd_buff[1] = error.raw; // TODO(Link Mauve): use the correct error code for that.
-            return error;
+            return MakeResult<bool>(false);
         }
         cmd_buff[1] = 0; // No error
         return MakeResult<bool>(false);
diff --git a/src/core/hle/kernel/kernel.h b/src/core/hle/kernel/kernel.h
index 85e3264b9..7e0f15c84 100644
--- a/src/core/hle/kernel/kernel.h
+++ b/src/core/hle/kernel/kernel.h
@@ -22,7 +22,7 @@ enum KernelHandle {
 enum class HandleType : u32 {
     Unknown         = 0,
     Port            = 1,
-    Service         = 2,
+    Session         = 2,
     Event           = 3,
     Mutex           = 4,
     SharedMemory    = 5,
@@ -30,10 +30,7 @@ enum class HandleType : u32 {
     Thread          = 7,
     Process         = 8,
     AddressArbiter  = 9,
-    File            = 10,
-    Semaphore       = 11,
-    Archive         = 12,
-    Directory       = 13,
+    Semaphore       = 10,
 };
 
 enum {
@@ -53,15 +50,6 @@ public:
     virtual Kernel::HandleType GetHandleType() const = 0;
 
     /**
-     * Synchronize kernel object.
-     * @return True if the current thread should wait as a result of the sync
-     */
-    virtual ResultVal<bool> SyncRequest() {
-        LOG_ERROR(Kernel, "(UNIMPLEMENTED)");
-        return UnimplementedFunction(ErrorModule::Kernel);
-    }
-
-    /**
      * Wait for kernel object to synchronize.
      * @return True if the current thread should wait as a result of the wait
      */
diff --git a/src/core/hle/kernel/session.h b/src/core/hle/kernel/session.h
new file mode 100644
index 000000000..06ae4bc39
--- /dev/null
+++ b/src/core/hle/kernel/session.h
@@ -0,0 +1,58 @@
+// Copyright 2014 Citra Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include "core/hle/kernel/kernel.h"
+
+namespace Kernel {
+
+static const int kCommandHeaderOffset = 0x80; ///< Offset into command buffer of header
+
+/**
+ * Returns a pointer to the command buffer in kernel memory
+ * @param offset Optional offset into command buffer
+ * @return Pointer to command buffer
+ */
+inline static u32* GetCommandBuffer(const int offset=0) {
+    return (u32*)Memory::GetPointer(Memory::KERNEL_MEMORY_VADDR + kCommandHeaderOffset + offset);
+}
+
+/**
+ * Kernel object representing the client endpoint of an IPC session. Sessions are the basic CTR-OS
+ * primitive for communication between different processes, and are used to implement service calls
+ * to the various system services.
+ *
+ * To make a service call, the client must write the command header and parameters to the buffer
+ * located at offset 0x80 of the TLS (Thread-Local Storage) area, then execute a SendSyncRequest
+ * SVC call with its Session handle. The kernel will read the command header, using it to marshall
+ * the parameters to the process at the server endpoint of the session. After the server replies to
+ * the request, the response is marshalled back to the caller's TLS buffer and control is
+ * transferred back to it.
+ *
+ * In Citra, only the client endpoint is currently implemented and only HLE calls, where the IPC
+ * request is answered by C++ code in the emulator, are supported. When SendSyncRequest is called
+ * with the session handle, this class's SyncRequest method is called, which should read the TLS
+ * buffer and emulate the call accordingly. Since the code can directly read the emulated memory,
+ * no parameter marshalling is done.
+ *
+ * In the long term, this should be turned into the full-fledged IPC mechanism implemented by
+ * CTR-OS so that IPC calls can be optionally handled by the real implementations of processes, as
+ * opposed to HLE simulations.
+ */
+class Session : public Object {
+public:
+    std::string GetTypeName() const override { return "Session"; }
+
+    static Kernel::HandleType GetStaticHandleType() { return Kernel::HandleType::Session; }
+    Kernel::HandleType GetHandleType() const override { return Kernel::HandleType::Session; }
+
+    /**
+     * Handles a synchronous call to this session using HLE emulation. Emulated <-> emulated calls
+     * aren't supported yet.
+     */
+    virtual ResultVal<bool> SyncRequest() = 0;
+};
+
+}
diff --git a/src/core/hle/service/ac_u.cpp b/src/core/hle/service/ac_u.cpp
index 4130feb9d..311682abf 100644
--- a/src/core/hle/service/ac_u.cpp
+++ b/src/core/hle/service/ac_u.cpp
@@ -18,7 +18,7 @@ namespace AC_U {
  *      2 : Output connection type, 0 = none, 1 = Old3DS Internet, 2 = New3DS Internet.
  */
 void GetWifiStatus(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
 
     // TODO(purpasmart96): This function is only a stub,
     // it returns a valid result without implementing full functionality.
diff --git a/src/core/hle/service/apt_u.cpp b/src/core/hle/service/apt_u.cpp
index b6d5d101f..ebfba4d8d 100644
--- a/src/core/hle/service/apt_u.cpp
+++ b/src/core/hle/service/apt_u.cpp
@@ -40,7 +40,7 @@ enum class SignalType : u32 {
 };
 
 void Initialize(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
 
     cmd_buff[3] = Kernel::CreateEvent(RESETTYPE_ONESHOT, "APT_U:Menu");  // APT menu event handle
     cmd_buff[4] = Kernel::CreateEvent(RESETTYPE_ONESHOT, "APT_U:Pause"); // APT pause event handle
@@ -57,7 +57,7 @@ void Initialize(Service::Interface* self) {
 }
 
 void GetLockHandle(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
     u32 flags = cmd_buff[1]; // TODO(bunnei): Figure out the purpose of the flag field
 
     if (0 == lock_handle) {
@@ -78,14 +78,14 @@ void GetLockHandle(Service::Interface* self) {
 }
 
 void Enable(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
     u32 unk = cmd_buff[1]; // TODO(bunnei): What is this field used for?
     cmd_buff[1] = 0; // No error
     LOG_WARNING(Service_APT, "(STUBBED) called unk=0x%08X", unk);
 }
 
 void InquireNotification(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
     u32 app_id = cmd_buff[2];
     cmd_buff[1] = 0; // No error
     cmd_buff[2] = static_cast<u32>(SignalType::None); // Signal type
@@ -112,7 +112,7 @@ void InquireNotification(Service::Interface* self) {
  *      8 : Output parameter buffer ptr
  */
 void ReceiveParameter(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
     u32 app_id = cmd_buff[1];
     u32 buffer_size = cmd_buff[2];
     cmd_buff[1] = 0; // No error
@@ -143,7 +143,7 @@ void ReceiveParameter(Service::Interface* self) {
  *      8 : Output parameter buffer ptr
  */
 void GlanceParameter(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
     u32 app_id = cmd_buff[1];
     u32 buffer_size = cmd_buff[2];
 
@@ -170,7 +170,7 @@ void GlanceParameter(Service::Interface* self) {
  *      1 : Result of function, 0 on success, otherwise error code
  */
 void AppletUtility(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
 
     // These are from 3dbrew - I'm not really sure what they're used for.
     u32 unk = cmd_buff[1];
@@ -196,7 +196,7 @@ void AppletUtility(Service::Interface* self) {
 void GetSharedFont(Service::Interface* self) {
     LOG_TRACE(Kernel_SVC, "called");
 
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
 
     if (!shared_font.empty()) {
         // TODO(bunnei): This function shouldn't copy the shared font every time it's called.
diff --git a/src/core/hle/service/cfg_u.cpp b/src/core/hle/service/cfg_u.cpp
index 972cc0534..2e9d7bf21 100644
--- a/src/core/hle/service/cfg_u.cpp
+++ b/src/core/hle/service/cfg_u.cpp
@@ -52,7 +52,7 @@ static const std::array<u16, 187> country_codes = {
  *      2 : Country's 2-char string
  */
 static void GetCountryCodeString(Service::Interface* self) {
-    u32* cmd_buffer = Service::GetCommandBuffer();
+    u32* cmd_buffer = Kernel::GetCommandBuffer();
     u32 country_code_id = cmd_buffer[1];
 
     if (country_code_id >= country_codes.size() || 0 == country_codes[country_code_id]) {
@@ -74,7 +74,7 @@ static void GetCountryCodeString(Service::Interface* self) {
  *      2 : Country Code ID
  */
 static void GetCountryCodeID(Service::Interface* self) {
-    u32* cmd_buffer = Service::GetCommandBuffer();
+    u32* cmd_buffer = Kernel::GetCommandBuffer();
     u16 country_code = cmd_buffer[1];
     u16 country_code_id = 0;
 
diff --git a/src/core/hle/service/dsp_dsp.cpp b/src/core/hle/service/dsp_dsp.cpp
index ce1c9938d..bd82063c6 100644
--- a/src/core/hle/service/dsp_dsp.cpp
+++ b/src/core/hle/service/dsp_dsp.cpp
@@ -25,7 +25,7 @@ static Handle interrupt_event;
  *      2 : (inaddr << 1) + 0x1FF40000 (where 0x1FF00000 is the DSP RAM address)
  */
 void ConvertProcessAddressFromDspDram(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
 
     u32 addr = cmd_buff[1];
 
@@ -48,7 +48,7 @@ void ConvertProcessAddressFromDspDram(Service::Interface* self) {
  *      2 : Component loaded, 0 on not loaded, 1 on loaded
  */
 void LoadComponent(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
 
     cmd_buff[1] = 0; // No error
     cmd_buff[2] = 1; // Pretend that we actually loaded the DSP firmware
@@ -65,7 +65,7 @@ void LoadComponent(Service::Interface* self) {
  *      3 : Semaphore event handle
  */
 void GetSemaphoreEventHandle(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
 
     cmd_buff[1] = 0; // No error
     cmd_buff[3] = semaphore_event; // Event handle
@@ -83,7 +83,7 @@ void GetSemaphoreEventHandle(Service::Interface* self) {
  *      1 : Result of function, 0 on success, otherwise error code
  */
 void RegisterInterruptEvents(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
 
     interrupt_event = static_cast<Handle>(cmd_buff[4]);
 
@@ -100,7 +100,7 @@ void RegisterInterruptEvents(Service::Interface* self) {
  *      1 : Result of function, 0 on success, otherwise error code
  */
 void WriteReg0x10(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
 
     Kernel::SignalEvent(interrupt_event);
 
@@ -121,7 +121,7 @@ void WriteReg0x10(Service::Interface* self) {
  *      2 : Number of bytes read from pipe
  */
 void ReadPipeIfPossible(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
 
     u32 size = cmd_buff[3] & 0xFFFF;// Lower 16 bits are size
     VAddr addr = cmd_buff[0x41];
diff --git a/src/core/hle/service/fs_user.cpp b/src/core/hle/service/fs_user.cpp
index 9bda4fe8a..672ba2475 100644
--- a/src/core/hle/service/fs_user.cpp
+++ b/src/core/hle/service/fs_user.cpp
@@ -17,7 +17,7 @@
 namespace FS_User {
 
 static void Initialize(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
 
     // TODO(Link Mauve): check the behavior when cmd_buff[1] isn't 32, as per
     // http://3dbrew.org/wiki/FS:Initialize#Request
@@ -43,7 +43,7 @@ static void Initialize(Service::Interface* self) {
  *      3 : File handle
  */
 static void OpenFile(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
 
     // TODO(Link Mauve): cmd_buff[2], aka archive handle lower word, isn't used according to
     // 3dmoo's or ctrulib's implementations.  Triple check if it's really the case.
@@ -86,7 +86,7 @@ static void OpenFile(Service::Interface* self) {
  *      3 : File handle
  */
 static void OpenFileDirectly(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
 
     auto archive_id       = static_cast<FileSys::Archive::IdCode>(cmd_buff[2]);
     auto archivename_type = static_cast<FileSys::LowPathType>(cmd_buff[3]);
@@ -141,7 +141,7 @@ static void OpenFileDirectly(Service::Interface* self) {
  *      1 : Result of function, 0 on success, otherwise error code
  */
 void DeleteFile(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
 
     // TODO(Link Mauve): cmd_buff[2], aka archive handle lower word, isn't used according to
     // 3dmoo's or ctrulib's implementations.  Triple check if it's really the case.
@@ -175,7 +175,7 @@ void DeleteFile(Service::Interface* self) {
  *      1 : Result of function, 0 on success, otherwise error code
  */
 void RenameFile(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
 
     // TODO(Link Mauve): cmd_buff[2] and cmd_buff[6], aka archive handle lower word, aren't used according to
     // 3dmoo's or ctrulib's implementations.  Triple check if it's really the case.
@@ -210,7 +210,7 @@ void RenameFile(Service::Interface* self) {
  *      1 : Result of function, 0 on success, otherwise error code
  */
 void DeleteDirectory(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
 
     // TODO(Link Mauve): cmd_buff[2], aka archive handle lower word, isn't used according to
     // 3dmoo's or ctrulib's implementations.  Triple check if it's really the case.
@@ -239,7 +239,7 @@ void DeleteDirectory(Service::Interface* self) {
  *      1 : Result of function, 0 on success, otherwise error code
  */
 static void CreateDirectory(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
 
     // TODO: cmd_buff[2], aka archive handle lower word, isn't used according to
     // 3dmoo's or ctrulib's implementations.  Triple check if it's really the case.
@@ -272,7 +272,7 @@ static void CreateDirectory(Service::Interface* self) {
  *      1 : Result of function, 0 on success, otherwise error code
  */
 void RenameDirectory(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
 
     // TODO(Link Mauve): cmd_buff[2] and cmd_buff[6], aka archive handle lower word, aren't used according to
     // 3dmoo's or ctrulib's implementations.  Triple check if it's really the case.
@@ -296,7 +296,7 @@ void RenameDirectory(Service::Interface* self) {
 }
 
 static void OpenDirectory(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
 
     // TODO(Link Mauve): cmd_buff[2], aka archive handle lower word, isn't used according to
     // 3dmoo's or ctrulib's implementations.  Triple check if it's really the case.
@@ -332,7 +332,7 @@ static void OpenDirectory(Service::Interface* self) {
  *      3 : Archive handle upper word (same as file handle)
  */
 static void OpenArchive(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
 
     auto archive_id       = static_cast<FileSys::Archive::IdCode>(cmd_buff[1]);
     auto archivename_type = static_cast<FileSys::LowPathType>(cmd_buff[2]);
@@ -365,7 +365,7 @@ static void OpenArchive(Service::Interface* self) {
 *      2 : Whether the Sdmc could be detected
 */
 static void IsSdmcDetected(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
 
     cmd_buff[1] = 0;
     cmd_buff[2] = Settings::values.use_virtual_sd ? 1 : 0;
diff --git a/src/core/hle/service/gsp_gpu.cpp b/src/core/hle/service/gsp_gpu.cpp
index 223800560..db8027142 100644
--- a/src/core/hle/service/gsp_gpu.cpp
+++ b/src/core/hle/service/gsp_gpu.cpp
@@ -72,7 +72,7 @@ static void WriteHWRegs(u32 base_address, u32 size_in_bytes, const u32* data) {
 
 /// Write a GSP GPU hardware register
 static void WriteHWRegs(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
     u32 reg_addr = cmd_buff[1];
     u32 size = cmd_buff[2];
 
@@ -83,7 +83,7 @@ static void WriteHWRegs(Service::Interface* self) {
 
 /// Read a GSP GPU hardware register
 static void ReadHWRegs(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
     u32 reg_addr = cmd_buff[1];
     u32 size = cmd_buff[2];
 
@@ -136,7 +136,7 @@ static void SetBufferSwap(u32 screen_id, const FrameBufferInfo& info) {
  *      1: Result code
  */
 static void SetBufferSwap(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
     u32 screen_id = cmd_buff[1];
     FrameBufferInfo* fb_info = (FrameBufferInfo*)&cmd_buff[2];
     SetBufferSwap(screen_id, *fb_info);
@@ -155,7 +155,7 @@ static void SetBufferSwap(Service::Interface* self) {
  *      4 : Handle to GSP shared memory
  */
 static void RegisterInterruptRelayQueue(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
     u32 flags = cmd_buff[1];
     g_interrupt_event = cmd_buff[3];
     g_shared_memory = Kernel::CreateSharedMemory("GSPSharedMem");
@@ -323,7 +323,7 @@ static void TriggerCmdReqQueue(Service::Interface* self) {
         }
     }
 
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
     cmd_buff[1] = 0; // No error
 }
 
diff --git a/src/core/hle/service/hid_user.cpp b/src/core/hle/service/hid_user.cpp
index 5772199d4..eb2d35964 100644
--- a/src/core/hle/service/hid_user.cpp
+++ b/src/core/hle/service/hid_user.cpp
@@ -153,7 +153,7 @@ void PadUpdateComplete() {
  *      8 : Event signaled by HID_User
  */
 static void GetIPCHandles(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
 
     cmd_buff[1] = 0; // No error
     cmd_buff[3] = shared_mem;
diff --git a/src/core/hle/service/ptm_u.cpp b/src/core/hle/service/ptm_u.cpp
index 559f148dd..b8c0f6da8 100644
--- a/src/core/hle/service/ptm_u.cpp
+++ b/src/core/hle/service/ptm_u.cpp
@@ -34,7 +34,7 @@ static bool battery_is_charging = true;
  *      2 : Output of function, 0 = not charging, 1 = charging.
  */
 static void GetAdapterState(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
 
     // TODO(purpasmart96): This function is only a stub,
     // it returns a valid result without implementing full functionality.
@@ -52,7 +52,7 @@ static void GetAdapterState(Service::Interface* self) {
  *      2 : Whether the 3DS's physical shell casing is open (1) or closed (0)
  */
 static void GetShellState(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
 
     cmd_buff[1] = 0;
     cmd_buff[2] = shell_open ? 1 : 0;
@@ -68,7 +68,7 @@ static void GetShellState(Service::Interface* self) {
  *          3 = half full battery, 2 =  low battery, 1 = critical battery.
  */
 static void GetBatteryLevel(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
 
     // TODO(purpasmart96): This function is only a stub,
     // it returns a valid result without implementing full functionality.
@@ -86,7 +86,7 @@ static void GetBatteryLevel(Service::Interface* self) {
  *      2 : Output of function, 0 = not charging, 1 = charging.
  */
 static void GetBatteryChargeState(Service::Interface* self) {
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
 
     // TODO(purpasmart96): This function is only a stub,
     // it returns a valid result without implementing full functionality.
diff --git a/src/core/hle/service/service.h b/src/core/hle/service/service.h
index baae910a1..9cd906150 100644
--- a/src/core/hle/service/service.h
+++ b/src/core/hle/service/service.h
@@ -14,6 +14,7 @@
 #include "core/mem_map.h"
 
 #include "core/hle/kernel/kernel.h"
+#include "core/hle/kernel/session.h"
 #include "core/hle/svc.h"
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
@@ -21,30 +22,19 @@
 
 namespace Service {
 
-static const int kMaxPortSize           = 0x08; ///< Maximum size of a port name (8 characters)
-static const int kCommandHeaderOffset   = 0x80; ///< Offset into command buffer of header
-
-/**
- * Returns a pointer to the command buffer in kernel memory
- * @param offset Optional offset into command buffer
- * @return Pointer to command buffer
- */
-inline static u32* GetCommandBuffer(const int offset=0) {
-    return (u32*)Memory::GetPointer(Memory::KERNEL_MEMORY_VADDR + kCommandHeaderOffset + offset);
-}
+static const int kMaxPortSize = 8; ///< Maximum size of a port name (8 characters)
 
 class Manager;
 
 /// Interface to a CTROS service
-class Interface  : public Kernel::Object {
+class Interface  : public Kernel::Session {
+    // TODO(yuriks): An "Interface" being a Kernel::Object is mostly non-sense. Interface should be
+    // just something that encapsulates a session and acts as a helper to implement service
+    // processes.
+
     friend class Manager;
 public:
-
     std::string GetName() const override { return GetPortName(); }
-    std::string GetTypeName() const override { return GetPortName(); }
-
-    static Kernel::HandleType GetStaticHandleType() { return Kernel::HandleType::Service; }
-    Kernel::HandleType GetHandleType() const override { return Kernel::HandleType::Service; }
 
     typedef void (*Function)(Interface*);
 
@@ -77,7 +67,7 @@ public:
     }
 
     ResultVal<bool> SyncRequest() override {
-        u32* cmd_buff = GetCommandBuffer();
+        u32* cmd_buff = Kernel::GetCommandBuffer();
         auto itr = m_functions.find(cmd_buff[0]);
 
         if (itr == m_functions.end() || itr->second.func == nullptr) {
diff --git a/src/core/hle/service/srv.cpp b/src/core/hle/service/srv.cpp
index 24a846533..165fd7aac 100644
--- a/src/core/hle/service/srv.cpp
+++ b/src/core/hle/service/srv.cpp
@@ -16,7 +16,7 @@ static Handle g_event_handle = 0;
 static void Initialize(Service::Interface* self) {
     LOG_DEBUG(Service_SRV, "called");
 
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
 
     cmd_buff[1] = 0; // No error
 }
@@ -24,7 +24,7 @@ static void Initialize(Service::Interface* self) {
 static void GetProcSemaphore(Service::Interface* self) {
     LOG_TRACE(Service_SRV, "called");
 
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
 
     // TODO(bunnei): Change to a semaphore once these have been implemented
     g_event_handle = Kernel::CreateEvent(RESETTYPE_ONESHOT, "SRV:Event");
@@ -36,7 +36,7 @@ static void GetProcSemaphore(Service::Interface* self) {
 
 static void GetServiceHandle(Service::Interface* self) {
     ResultCode res = RESULT_SUCCESS;
-    u32* cmd_buff = Service::GetCommandBuffer();
+    u32* cmd_buff = Kernel::GetCommandBuffer();
 
     std::string port_name = std::string((const char*)&cmd_buff[1], 0, Service::kMaxPortSize);
     Service::Interface* service = Service::g_manager->FetchFromPortName(port_name);
diff --git a/src/core/hle/svc.cpp b/src/core/hle/svc.cpp
index f3595096e..15cc240f4 100644
--- a/src/core/hle/svc.cpp
+++ b/src/core/hle/svc.cpp
@@ -88,17 +88,14 @@ static Result ConnectToPort(Handle* out, const char* port_name) {
 
 /// Synchronize to an OS service
 static Result SendSyncRequest(Handle handle) {
-    // TODO(yuriks): ObjectPool::Get tries to check the Object type, which fails since this is a generic base Object,
-    // so we are forced to use GetFast and manually verify the handle.
-    if (!Kernel::g_object_pool.IsValid(handle)) {
+    Kernel::Session* session = Kernel::g_object_pool.Get<Kernel::Session>(handle);
+    if (session == nullptr) {
         return InvalidHandle(ErrorModule::Kernel).raw;
     }
-    Kernel::Object* object = Kernel::g_object_pool.GetFast<Kernel::Object>(handle);
 
-    _assert_msg_(KERNEL, (object != nullptr), "called, but kernel object is nullptr!");
-    LOG_TRACE(Kernel_SVC, "called handle=0x%08X(%s)", handle, object->GetTypeName().c_str());
+    LOG_TRACE(Kernel_SVC, "called handle=0x%08X(%s)", handle, session->GetName().c_str());
 
-    ResultVal<bool> wait = object->SyncRequest();
+    ResultVal<bool> wait = session->SyncRequest();
     if (wait.Succeeded() && *wait) {
         Kernel::WaitCurrentThread(WAITTYPE_SYNCH); // TODO(bunnei): Is this correct?
     }