22 files changed, 546 insertions, 44 deletions

diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index 1bc536075..6ad04d19d 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -7,6 +7,8 @@ add_library(core STATIC
     core_timing.cpp
     core_timing.h
     file_sys/directory.h
+    file_sys/disk_filesystem.cpp
+    file_sys/disk_filesystem.h
     file_sys/errors.h
     file_sys/filesystem.cpp
     file_sys/filesystem.h
@@ -18,6 +20,8 @@ add_library(core STATIC
     file_sys/romfs_factory.h
     file_sys/romfs_filesystem.cpp
     file_sys/romfs_filesystem.h
+    file_sys/savedata_factory.cpp
+    file_sys/savedata_factory.h
     file_sys/storage.h
     frontend/emu_window.cpp
     frontend/emu_window.h
diff --git a/src/core/file_sys/disk_filesystem.cpp b/src/core/file_sys/disk_filesystem.cpp
new file mode 100644
index 000000000..be7574fdb
--- /dev/null
+++ b/src/core/file_sys/disk_filesystem.cpp
@@ -0,0 +1,147 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <cstring>
+#include <memory>
+#include "common/common_types.h"
+#include "common/logging/log.h"
+#include "core/file_sys/disk_filesystem.h"
+
+namespace FileSys {
+
+std::string Disk_FileSystem::GetName() const {
+    return "Disk";
+}
+
+ResultVal<std::unique_ptr<StorageBackend>> Disk_FileSystem::OpenFile(const std::string& path,
+                                                                     Mode mode) const {
+    ASSERT_MSG(mode == Mode::Read || mode == Mode::Write, "Other file modes are not supported");
+
+    std::string full_path = base_directory + path;
+    auto file = std::make_shared<FileUtil::IOFile>(full_path, mode == Mode::Read ? "rb" : "wb");
+
+    if (!file->IsOpen()) {
+        // TODO(Subv): Find out the correct error code.
+        return ResultCode(-1);
+    }
+
+    return MakeResult<std::unique_ptr<StorageBackend>>(
+        std::make_unique<Disk_Storage>(std::move(file)));
+}
+
+ResultCode Disk_FileSystem::DeleteFile(const Path& path) const {
+    LOG_WARNING(Service_FS, "(STUBBED) called");
+    // TODO(bunnei): Use correct error code
+    return ResultCode(-1);
+}
+
+ResultCode Disk_FileSystem::RenameFile(const Path& src_path, const Path& dest_path) const {
+    LOG_WARNING(Service_FS, "(STUBBED) called");
+    // TODO(wwylele): Use correct error code
+    return ResultCode(-1);
+}
+
+ResultCode Disk_FileSystem::DeleteDirectory(const Path& path) const {
+    LOG_WARNING(Service_FS, "(STUBBED) called");
+    // TODO(wwylele): Use correct error code
+    return ResultCode(-1);
+}
+
+ResultCode Disk_FileSystem::DeleteDirectoryRecursively(const Path& path) const {
+    LOG_WARNING(Service_FS, "(STUBBED) called");
+    // TODO(wwylele): Use correct error code
+    return ResultCode(-1);
+}
+
+ResultCode Disk_FileSystem::CreateFile(const std::string& path, u64 size) const {
+    LOG_WARNING(Service_FS, "(STUBBED) called");
+
+    std::string full_path = base_directory + path;
+    if (size == 0) {
+        FileUtil::CreateEmptyFile(full_path);
+        return RESULT_SUCCESS;
+    }
+
+    FileUtil::IOFile file(full_path, "wb");
+    // Creates a sparse file (or a normal file on filesystems without the concept of sparse files)
+    // We do this by seeking to the right size, then writing a single null byte.
+    if (file.Seek(size - 1, SEEK_SET) && file.WriteBytes("", 1) == 1) {
+        return RESULT_SUCCESS;
+    }
+
+    LOG_ERROR(Service_FS, "Too large file");
+    // TODO(Subv): Find out the correct error code
+    return ResultCode(-1);
+}
+
+ResultCode Disk_FileSystem::CreateDirectory(const Path& path) const {
+    LOG_WARNING(Service_FS, "(STUBBED) called");
+    // TODO(wwylele): Use correct error code
+    return ResultCode(-1);
+}
+
+ResultCode Disk_FileSystem::RenameDirectory(const Path& src_path, const Path& dest_path) const {
+    LOG_WARNING(Service_FS, "(STUBBED) called");
+    // TODO(wwylele): Use correct error code
+    return ResultCode(-1);
+}
+
+ResultVal<std::unique_ptr<DirectoryBackend>> Disk_FileSystem::OpenDirectory(
+    const Path& path) const {
+    return MakeResult<std::unique_ptr<DirectoryBackend>>(std::make_unique<Disk_Directory>());
+}
+
+u64 Disk_FileSystem::GetFreeSpaceSize() const {
+    LOG_WARNING(Service_FS, "(STUBBED) called");
+    return 0;
+}
+
+ResultVal<FileSys::EntryType> Disk_FileSystem::GetEntryType(const std::string& path) const {
+    std::string full_path = base_directory + path;
+    if (!FileUtil::Exists(full_path)) {
+        // TODO(Subv): Find out what this actually means
+        return ResultCode(ErrorModule::FS, 1);
+    }
+
+    // TODO(Subv): Find out the EntryType values
+    UNIMPLEMENTED_MSG("Unimplemented GetEntryType");
+}
+
+ResultVal<size_t> Disk_Storage::Read(const u64 offset, const size_t length, u8* buffer) const {
+    LOG_TRACE(Service_FS, "called offset=%llu, length=%zu", offset, length);
+    file->Seek(offset, SEEK_SET);
+    return MakeResult<size_t>(file->ReadBytes(buffer, length));
+}
+
+ResultVal<size_t> Disk_Storage::Write(const u64 offset, const size_t length, const bool flush,
+                                      const u8* buffer) const {
+    LOG_WARNING(Service_FS, "(STUBBED) called");
+    file->Seek(offset, SEEK_SET);
+    size_t written = file->WriteBytes(buffer, length);
+    if (flush) {
+        file->Flush();
+    }
+    return MakeResult<size_t>(written);
+}
+
+u64 Disk_Storage::GetSize() const {
+    return file->GetSize();
+}
+
+bool Disk_Storage::SetSize(const u64 size) const {
+    LOG_WARNING(Service_FS, "(STUBBED) called");
+    return false;
+}
+
+u32 Disk_Directory::Read(const u32 count, Entry* entries) {
+    LOG_WARNING(Service_FS, "(STUBBED) called");
+    return 0;
+}
+
+bool Disk_Directory::Close() const {
+    LOG_WARNING(Service_FS, "(STUBBED) called");
+    return true;
+}
+
+} // namespace FileSys
diff --git a/src/core/file_sys/disk_filesystem.h b/src/core/file_sys/disk_filesystem.h
new file mode 100644
index 000000000..53767b949
--- /dev/null
+++ b/src/core/file_sys/disk_filesystem.h
@@ -0,0 +1,66 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <cstddef>
+#include <memory>
+#include <string>
+#include "common/common_types.h"
+#include "common/file_util.h"
+#include "core/file_sys/directory.h"
+#include "core/file_sys/filesystem.h"
+#include "core/file_sys/storage.h"
+#include "core/hle/result.h"
+
+namespace FileSys {
+
+class Disk_FileSystem : public FileSystemBackend {
+public:
+    explicit Disk_FileSystem(std::string base_directory)
+        : base_directory(std::move(base_directory)) {}
+
+    std::string GetName() const override;
+
+    ResultVal<std::unique_ptr<StorageBackend>> OpenFile(const std::string& path,
+                                                        Mode mode) const override;
+    ResultCode DeleteFile(const Path& path) const override;
+    ResultCode RenameFile(const Path& src_path, const Path& dest_path) const override;
+    ResultCode DeleteDirectory(const Path& path) const override;
+    ResultCode DeleteDirectoryRecursively(const Path& path) const override;
+    ResultCode CreateFile(const std::string& path, u64 size) const override;
+    ResultCode CreateDirectory(const Path& path) const override;
+    ResultCode RenameDirectory(const Path& src_path, const Path& dest_path) const override;
+    ResultVal<std::unique_ptr<DirectoryBackend>> OpenDirectory(const Path& path) const override;
+    u64 GetFreeSpaceSize() const override;
+    ResultVal<EntryType> GetEntryType(const std::string& path) const override;
+
+protected:
+    std::string base_directory;
+};
+
+class Disk_Storage : public StorageBackend {
+public:
+    Disk_Storage(std::shared_ptr<FileUtil::IOFile> file) : file(std::move(file)) {}
+
+    ResultVal<size_t> Read(u64 offset, size_t length, u8* buffer) const override;
+    ResultVal<size_t> Write(u64 offset, size_t length, bool flush, const u8* buffer) const override;
+    u64 GetSize() const override;
+    bool SetSize(u64 size) const override;
+    bool Close() const override {
+        return false;
+    }
+    void Flush() const override {}
+
+private:
+    std::shared_ptr<FileUtil::IOFile> file;
+};
+
+class Disk_Directory : public DirectoryBackend {
+public:
+    u32 Read(const u32 count, Entry* entries) override;
+    bool Close() const override;
+};
+
+} // namespace FileSys
diff --git a/src/core/file_sys/filesystem.h b/src/core/file_sys/filesystem.h
index 02705506b..df4e66a0b 100644
--- a/src/core/file_sys/filesystem.h
+++ b/src/core/file_sys/filesystem.h
@@ -27,11 +27,14 @@ enum LowPathType : u32 {
     Wchar = 4,
 };
 
-union Mode {
-    u32 hex;
-    BitField<0, 1, u32> read_flag;
-    BitField<1, 1, u32> write_flag;
-    BitField<2, 1, u32> create_flag;
+enum EntryType : u32 {
+    Directory = 0,
+    File = 1,
+};
+
+enum class Mode : u32 {
+    Read = 1,
+    Write = 2,
 };
 
 class Path {
@@ -86,7 +89,7 @@ public:
      * @param size The size of the new file, filled with zeroes
      * @return Result of the operation
      */
-    virtual ResultCode CreateFile(const Path& path, u64 size) const = 0;
+    virtual ResultCode CreateFile(const std::string& path, u64 size) const = 0;
 
     /**
      * Delete a file specified by its path
@@ -138,8 +141,8 @@ public:
      * @param mode Mode to open the file with
      * @return Opened file, or error code
      */
-    virtual ResultVal<std::unique_ptr<StorageBackend>> OpenFile(const Path& path,
-                                                                const Mode& mode) const = 0;
+    virtual ResultVal<std::unique_ptr<StorageBackend>> OpenFile(const std::string& path,
+                                                                Mode mode) const = 0;
 
     /**
      * Open a directory specified by its path
@@ -153,6 +156,12 @@ public:
      * @return The number of free bytes in the archive
      */
     virtual u64 GetFreeSpaceSize() const = 0;
+
+    /**
+     * Get the type of the specified path
+     * @return The type of the specified path or error code
+     */
+    virtual ResultVal<EntryType> GetEntryType(const std::string& path) const = 0;
 };
 
 class FileSystemFactory : NonCopyable {
diff --git a/src/core/file_sys/romfs_filesystem.cpp b/src/core/file_sys/romfs_filesystem.cpp
index ca1463d7c..f1f9b4d04 100644
--- a/src/core/file_sys/romfs_filesystem.cpp
+++ b/src/core/file_sys/romfs_filesystem.cpp
@@ -14,8 +14,8 @@ std::string RomFS_FileSystem::GetName() const {
     return "RomFS";
 }
 
-ResultVal<std::unique_ptr<StorageBackend>> RomFS_FileSystem::OpenFile(const Path& path,
-                                                                      const Mode& mode) const {
+ResultVal<std::unique_ptr<StorageBackend>> RomFS_FileSystem::OpenFile(const std::string& path,
+                                                                      Mode mode) const {
     return MakeResult<std::unique_ptr<StorageBackend>>(
         std::make_unique<RomFS_Storage>(romfs_file, data_offset, data_size));
 }
@@ -48,7 +48,7 @@ ResultCode RomFS_FileSystem::DeleteDirectoryRecursively(const Path& path) const
     return ResultCode(-1);
 }
 
-ResultCode RomFS_FileSystem::CreateFile(const Path& path, u64 size) const {
+ResultCode RomFS_FileSystem::CreateFile(const std::string& path, u64 size) const {
     LOG_CRITICAL(Service_FS, "Attempted to create a file in an ROMFS archive (%s).",
                  GetName().c_str());
     // TODO(bunnei): Use correct error code
@@ -79,6 +79,12 @@ u64 RomFS_FileSystem::GetFreeSpaceSize() const {
     return 0;
 }
 
+ResultVal<FileSys::EntryType> RomFS_FileSystem::GetEntryType(const std::string& path) const {
+    LOG_CRITICAL(Service_FS, "Called within an ROMFS archive (path %s).", path.c_str());
+    // TODO(wwylele): Use correct error code
+    return ResultCode(-1);
+}
+
 ResultVal<size_t> RomFS_Storage::Read(const u64 offset, const size_t length, u8* buffer) const {
     LOG_TRACE(Service_FS, "called offset=%llu, length=%zu", offset, length);
     romfs_file->Seek(data_offset + offset, SEEK_SET);
diff --git a/src/core/file_sys/romfs_filesystem.h b/src/core/file_sys/romfs_filesystem.h
index 900ea567a..cedd70645 100644
--- a/src/core/file_sys/romfs_filesystem.h
+++ b/src/core/file_sys/romfs_filesystem.h
@@ -29,17 +29,18 @@ public:
 
     std::string GetName() const override;
 
-    ResultVal<std::unique_ptr<StorageBackend>> OpenFile(const Path& path,
-                                                        const Mode& mode) const override;
+    ResultVal<std::unique_ptr<StorageBackend>> OpenFile(const std::string& path,
+                                                        Mode mode) const override;
     ResultCode DeleteFile(const Path& path) const override;
     ResultCode RenameFile(const Path& src_path, const Path& dest_path) const override;
     ResultCode DeleteDirectory(const Path& path) const override;
     ResultCode DeleteDirectoryRecursively(const Path& path) const override;
-    ResultCode CreateFile(const Path& path, u64 size) const override;
+    ResultCode CreateFile(const std::string& path, u64 size) const override;
     ResultCode CreateDirectory(const Path& path) const override;
     ResultCode RenameDirectory(const Path& src_path, const Path& dest_path) const override;
     ResultVal<std::unique_ptr<DirectoryBackend>> OpenDirectory(const Path& path) const override;
     u64 GetFreeSpaceSize() const override;
+    ResultVal<EntryType> GetEntryType(const std::string& path) const override;
 
 protected:
     std::shared_ptr<FileUtil::IOFile> romfs_file;
diff --git a/src/core/file_sys/savedata_factory.cpp b/src/core/file_sys/savedata_factory.cpp
new file mode 100644
index 000000000..4d83e100f
--- /dev/null
+++ b/src/core/file_sys/savedata_factory.cpp
@@ -0,0 +1,42 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <cinttypes>
+#include <memory>
+#include "common/common_types.h"
+#include "common/logging/log.h"
+#include "common/string_util.h"
+#include "core/file_sys/disk_filesystem.h"
+#include "core/file_sys/savedata_factory.h"
+#include "core/hle/kernel/process.h"
+
+namespace FileSys {
+
+SaveData_Factory::SaveData_Factory(std::string nand_directory)
+    : nand_directory(std::move(nand_directory)) {}
+
+ResultVal<std::unique_ptr<FileSystemBackend>> SaveData_Factory::Open(const Path& path) {
+    u64 title_id = Kernel::g_current_process->program_id;
+    // TODO(Subv): Somehow obtain this value.
+    u32 user = 0;
+    std::string save_directory = Common::StringFromFormat("%ssave/%016" PRIX64 "/%08X",
+                                                          nand_directory.c_str(), title_id, user);
+    auto archive = std::make_unique<Disk_FileSystem>(save_directory);
+    return MakeResult<std::unique_ptr<FileSystemBackend>>(std::move(archive));
+}
+
+ResultCode SaveData_Factory::Format(const Path& path,
+                                    const FileSys::ArchiveFormatInfo& format_info) {
+    LOG_ERROR(Service_FS, "Unimplemented Format archive %s", GetName().c_str());
+    // TODO(bunnei): Find the right error code for this
+    return ResultCode(-1);
+}
+
+ResultVal<ArchiveFormatInfo> SaveData_Factory::GetFormatInfo(const Path& path) const {
+    LOG_ERROR(Service_FS, "Unimplemented GetFormatInfo archive %s", GetName().c_str());
+    // TODO(bunnei): Find the right error code for this
+    return ResultCode(-1);
+}
+
+} // namespace FileSys
diff --git a/src/core/file_sys/savedata_factory.h b/src/core/file_sys/savedata_factory.h
new file mode 100644
index 000000000..726743fde
--- /dev/null
+++ b/src/core/file_sys/savedata_factory.h
@@ -0,0 +1,31 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <memory>
+#include <string>
+#include "common/common_types.h"
+#include "core/file_sys/filesystem.h"
+#include "core/hle/result.h"
+
+namespace FileSys {
+
+/// File system interface to the SaveData archive
+class SaveData_Factory final : public FileSystemFactory {
+public:
+    explicit SaveData_Factory(std::string nand_directory);
+
+    std::string GetName() const override {
+        return "SaveData_Factory";
+    }
+    ResultVal<std::unique_ptr<FileSystemBackend>> Open(const Path& path) override;
+    ResultCode Format(const Path& path, const FileSys::ArchiveFormatInfo& format_info) override;
+    ResultVal<ArchiveFormatInfo> GetFormatInfo(const Path& path) const override;
+
+private:
+    std::string nand_directory;
+};
+
+} // namespace FileSys
diff --git a/src/core/hle/kernel/process.cpp b/src/core/hle/kernel/process.cpp
index 8e74059ea..bb6dc28d7 100644
--- a/src/core/hle/kernel/process.cpp
+++ b/src/core/hle/kernel/process.cpp
@@ -20,12 +20,9 @@ namespace Kernel {
 // Lists all processes that exist in the current session.
 static std::vector<SharedPtr<Process>> process_list;
 
-SharedPtr<CodeSet> CodeSet::Create(std::string name, u64 program_id) {
+SharedPtr<CodeSet> CodeSet::Create(std::string name) {
     SharedPtr<CodeSet> codeset(new CodeSet);
-
     codeset->name = std::move(name);
-    codeset->program_id = program_id;
-
     return codeset;
 }
 
@@ -34,13 +31,14 @@ CodeSet::~CodeSet() {}
 
 u32 Process::next_process_id;
 
-SharedPtr<Process> Process::Create(std::string&& name) {
+SharedPtr<Process> Process::Create(std::string&& name, u64 program_id) {
     SharedPtr<Process> process(new Process);
 
     process->name = std::move(name);
     process->flags.raw = 0;
     process->flags.memory_region.Assign(MemoryRegion::APPLICATION);
     process->status = ProcessStatus::Created;
+    process->program_id = program_id;
 
     process_list.push_back(process);
     return process;
diff --git a/src/core/hle/kernel/process.h b/src/core/hle/kernel/process.h
index add98472f..1de12efd3 100644
--- a/src/core/hle/kernel/process.h
+++ b/src/core/hle/kernel/process.h
@@ -56,7 +56,7 @@ class ResourceLimit;
 struct MemoryRegionInfo;
 
 struct CodeSet final : public Object {
-    static SharedPtr<CodeSet> Create(std::string name, u64 program_id);
+    static SharedPtr<CodeSet> Create(std::string name);
 
     std::string GetTypeName() const override {
         return "CodeSet";
@@ -72,8 +72,6 @@ struct CodeSet final : public Object {
 
     /// Name of the process
     std::string name;
-    /// Title ID corresponding to the process
-    u64 program_id;
 
     std::shared_ptr<std::vector<u8>> memory;
 
@@ -97,7 +95,7 @@ private:
 
 class Process final : public Object {
 public:
-    static SharedPtr<Process> Create(std::string&& name);
+    static SharedPtr<Process> Create(std::string&& name, u64 program_id);
 
     std::string GetTypeName() const override {
         return "Process";
@@ -113,6 +111,9 @@ public:
 
     static u32 next_process_id;
 
+    /// Title ID corresponding to the process
+    u64 program_id;
+
     /// Resource limit descriptor for this process
     SharedPtr<ResourceLimit> resource_limit;
 
diff --git a/src/core/hle/result.h b/src/core/hle/result.h
index 656e1b4a7..97fef7a48 100644
--- a/src/core/hle/result.h
+++ b/src/core/hle/result.h
@@ -108,11 +108,11 @@ union ResultCode {
     }
 
     constexpr bool IsSuccess() const {
-        return is_error.ExtractValue(raw) == 0;
+        return raw == 0;
     }
 
     constexpr bool IsError() const {
-        return is_error.ExtractValue(raw) == 1;
+        return raw != 0;
     }
 };
 
diff --git a/src/core/hle/service/filesystem/filesystem.cpp b/src/core/hle/service/filesystem/filesystem.cpp
index 4b47548fd..32752aea5 100644
--- a/src/core/hle/service/filesystem/filesystem.cpp
+++ b/src/core/hle/service/filesystem/filesystem.cpp
@@ -3,7 +3,9 @@
 // Refer to the license.txt file included.
 
 #include <boost/container/flat_map.hpp>
+#include "common/file_util.h"
 #include "core/file_sys/filesystem.h"
+#include "core/file_sys/savedata_factory.h"
 #include "core/hle/service/filesystem/filesystem.h"
 #include "core/hle/service/filesystem/fsp_srv.h"
 
@@ -41,12 +43,17 @@ ResultVal<std::unique_ptr<FileSys::FileSystemBackend>> OpenFileSystem(Type type,
     return itr->second->Open(path);
 }
 
-void UnregisterFileSystems() {
+void RegisterFileSystems() {
     filesystem_map.clear();
+
+    std::string nand_directory = FileUtil::GetUserPath(D_NAND_IDX);
+
+    auto savedata = std::make_unique<FileSys::SaveData_Factory>(std::move(nand_directory));
+    RegisterFileSystem(std::move(savedata), Type::SaveData);
 }
 
 void InstallInterfaces(SM::ServiceManager& service_manager) {
-    UnregisterFileSystems();
+    RegisterFileSystems();
     std::make_shared<FSP_SRV>()->InstallAsService(service_manager);
 }
 
diff --git a/src/core/hle/service/filesystem/filesystem.h b/src/core/hle/service/filesystem/filesystem.h
index a674c9493..80f318676 100644
--- a/src/core/hle/service/filesystem/filesystem.h
+++ b/src/core/hle/service/filesystem/filesystem.h
@@ -25,6 +25,7 @@ namespace FileSystem {
 /// Supported FileSystem types
 enum class Type {
     RomFS = 1,
+    SaveData = 2,
 };
 
 /**
diff --git a/src/core/hle/service/filesystem/fsp_srv.cpp b/src/core/hle/service/filesystem/fsp_srv.cpp
index 87a07e457..3ac5a96cb 100644
--- a/src/core/hle/service/filesystem/fsp_srv.cpp
+++ b/src/core/hle/service/filesystem/fsp_srv.cpp
@@ -2,6 +2,7 @@
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
+#include <cinttypes>
 #include "common/logging/log.h"
 #include "core/core.h"
 #include "core/file_sys/filesystem.h"
@@ -65,10 +66,186 @@ private:
     }
 };
 
+class IFile final : public ServiceFramework<IFile> {
+public:
+    explicit IFile(std::unique_ptr<FileSys::StorageBackend>&& backend)
+        : ServiceFramework("IFile"), backend(std::move(backend)) {
+        static const FunctionInfo functions[] = {
+            {0, &IFile::Read, "Read"}, {1, &IFile::Write, "Write"}, {2, nullptr, "Flush"},
+            {3, nullptr, "SetSize"},   {4, nullptr, "GetSize"},
+        };
+        RegisterHandlers(functions);
+    }
+
+private:
+    std::unique_ptr<FileSys::StorageBackend> backend;
+
+    void Read(Kernel::HLERequestContext& ctx) {
+        IPC::RequestParser rp{ctx};
+        const u64 unk = rp.Pop<u64>();
+        const s64 offset = rp.Pop<s64>();
+        const s64 length = rp.Pop<s64>();
+
+        LOG_DEBUG(Service_FS, "called, offset=0x%llx, length=0x%llx", offset, length);
+
+        // Error checking
+        if (length < 0) {
+            IPC::ResponseBuilder rb{ctx, 2};
+            rb.Push(ResultCode(ErrorModule::FS, ErrorDescription::InvalidLength));
+            return;
+        }
+        if (offset < 0) {
+            IPC::ResponseBuilder rb{ctx, 2};
+            rb.Push(ResultCode(ErrorModule::FS, ErrorDescription::InvalidOffset));
+            return;
+        }
+
+        // Read the data from the Storage backend
+        std::vector<u8> output(length);
+        ResultVal<size_t> res = backend->Read(offset, length, output.data());
+        if (res.Failed()) {
+            IPC::ResponseBuilder rb{ctx, 2};
+            rb.Push(res.Code());
+            return;
+        }
+
+        // Write the data to memory
+        ctx.WriteBuffer(output);
+
+        IPC::ResponseBuilder rb{ctx, 4};
+        rb.Push(RESULT_SUCCESS);
+        rb.Push(static_cast<u64>(*res));
+    }
+
+    void Write(Kernel::HLERequestContext& ctx) {
+        IPC::RequestParser rp{ctx};
+        const u64 unk = rp.Pop<u64>();
+        const s64 offset = rp.Pop<s64>();
+        const s64 length = rp.Pop<s64>();
+
+        LOG_DEBUG(Service_FS, "called, offset=0x%llx, length=0x%llx", offset, length);
+
+        // Error checking
+        if (length < 0) {
+            IPC::ResponseBuilder rb{ctx, 2};
+            rb.Push(ResultCode(ErrorModule::FS, ErrorDescription::InvalidLength));
+            return;
+        }
+        if (offset < 0) {
+            IPC::ResponseBuilder rb{ctx, 2};
+            rb.Push(ResultCode(ErrorModule::FS, ErrorDescription::InvalidOffset));
+            return;
+        }
+
+        // Write the data to the Storage backend
+        std::vector<u8> data = ctx.ReadBuffer();
+        ResultVal<size_t> res = backend->Write(offset, length, true, data.data());
+        if (res.Failed()) {
+            IPC::ResponseBuilder rb{ctx, 2};
+            rb.Push(res.Code());
+            return;
+        }
+
+        IPC::ResponseBuilder rb{ctx, 2};
+        rb.Push(RESULT_SUCCESS);
+    }
+};
+
+class IFileSystem final : public ServiceFramework<IFileSystem> {
+public:
+    explicit IFileSystem(std::unique_ptr<FileSys::FileSystemBackend>&& backend)
+        : ServiceFramework("IFileSystem"), backend(std::move(backend)) {
+        static const FunctionInfo functions[] = {
+            {0, &IFileSystem::CreateFile, "CreateFile"},
+            {7, &IFileSystem::GetEntryType, "GetEntryType"},
+            {8, &IFileSystem::OpenFile, "OpenFile"},
+            {10, &IFileSystem::Commit, "Commit"},
+        };
+        RegisterHandlers(functions);
+    }
+
+    void CreateFile(Kernel::HLERequestContext& ctx) {
+        IPC::RequestParser rp{ctx};
+
+        auto file_buffer = ctx.ReadBuffer();
+        auto end = std::find(file_buffer.begin(), file_buffer.end(), '\0');
+
+        std::string name(file_buffer.begin(), end);
+
+        u64 mode = rp.Pop<u64>();
+        u32 size = rp.Pop<u32>();
+
+        LOG_DEBUG(Service_FS, "called file %s mode 0x%" PRIX64 " size 0x%08X", name.c_str(), mode,
+                  size);
+
+        IPC::ResponseBuilder rb{ctx, 2};
+        rb.Push(backend->CreateFile(name, size));
+    }
+
+    void OpenFile(Kernel::HLERequestContext& ctx) {
+        IPC::RequestParser rp{ctx};
+
+        auto file_buffer = ctx.ReadBuffer();
+        auto end = std::find(file_buffer.begin(), file_buffer.end(), '\0');
+
+        std::string name(file_buffer.begin(), end);
+
+        auto mode = static_cast<FileSys::Mode>(rp.Pop<u32>());
+
+        LOG_DEBUG(Service_FS, "called file %s mode %u", name.c_str(), static_cast<u32>(mode));
+
+        auto result = backend->OpenFile(name, mode);
+        if (result.Failed()) {
+            IPC::ResponseBuilder rb{ctx, 2};
+            rb.Push(result.Code());
+            return;
+        }
+
+        auto file = std::move(result.Unwrap());
+
+        IPC::ResponseBuilder rb{ctx, 2, 0, 1};
+        rb.Push(RESULT_SUCCESS);
+        rb.PushIpcInterface<IFile>(std::move(file));
+    }
+
+    void GetEntryType(Kernel::HLERequestContext& ctx) {
+        IPC::RequestParser rp{ctx};
+
+        auto file_buffer = ctx.ReadBuffer();
+        auto end = std::find(file_buffer.begin(), file_buffer.end(), '\0');
+
+        std::string name(file_buffer.begin(), end);
+
+        LOG_DEBUG(Service_FS, "called file %s", name.c_str());
+
+        auto result = backend->GetEntryType(name);
+        if (result.Failed()) {
+            IPC::ResponseBuilder rb{ctx, 2};
+            rb.Push(result.Code());
+            return;
+        }
+
+        IPC::ResponseBuilder rb{ctx, 3};
+        rb.Push(RESULT_SUCCESS);
+        rb.Push<u32>(static_cast<u32>(*result));
+    }
+
+    void Commit(Kernel::HLERequestContext& ctx) {
+        LOG_WARNING(Service_FS, "(STUBBED) called");
+
+        IPC::ResponseBuilder rb{ctx, 2};
+        rb.Push(RESULT_SUCCESS);
+    }
+
+private:
+    std::unique_ptr<FileSys::FileSystemBackend> backend;
+};
+
 FSP_SRV::FSP_SRV() : ServiceFramework("fsp-srv") {
     static const FunctionInfo functions[] = {
         {1, &FSP_SRV::Initalize, "Initalize"},
         {18, &FSP_SRV::MountSdCard, "MountSdCard"},
+        {51, &FSP_SRV::MountSaveData, "MountSaveData"},
         {200, &FSP_SRV::OpenDataStorageByCurrentProcess, "OpenDataStorageByCurrentProcess"},
         {202, nullptr, "OpenDataStorageByDataId"},
         {203, &FSP_SRV::OpenRomStorage, "OpenRomStorage"},
@@ -102,6 +279,17 @@ void FSP_SRV::MountSdCard(Kernel::HLERequestContext& ctx) {
     rb.Push(RESULT_SUCCESS);
 }
 
+void FSP_SRV::MountSaveData(Kernel::HLERequestContext& ctx) {
+    LOG_WARNING(Service_FS, "(STUBBED) called");
+
+    FileSys::Path unused;
+    auto filesystem = OpenFileSystem(Type::SaveData, unused).Unwrap();
+
+    IPC::ResponseBuilder rb{ctx, 2, 0, 1};
+    rb.Push(RESULT_SUCCESS);
+    rb.PushIpcInterface<IFileSystem>(std::move(filesystem));
+}
+
 void FSP_SRV::GetGlobalAccessLogMode(Kernel::HLERequestContext& ctx) {
     LOG_WARNING(Service_FS, "(STUBBED) called");
 
diff --git a/src/core/hle/service/filesystem/fsp_srv.h b/src/core/hle/service/filesystem/fsp_srv.h
index 56afc4b90..f19b2f2c4 100644
--- a/src/core/hle/service/filesystem/fsp_srv.h
+++ b/src/core/hle/service/filesystem/fsp_srv.h
@@ -24,6 +24,7 @@ private:
 
     void Initalize(Kernel::HLERequestContext& ctx);
     void MountSdCard(Kernel::HLERequestContext& ctx);
+    void MountSaveData(Kernel::HLERequestContext& ctx);
     void GetGlobalAccessLogMode(Kernel::HLERequestContext& ctx);
     void OpenDataStorageByCurrentProcess(Kernel::HLERequestContext& ctx);
     void OpenRomStorage(Kernel::HLERequestContext& ctx);
diff --git a/src/core/loader/deconstructed_rom_directory.cpp b/src/core/loader/deconstructed_rom_directory.cpp
index 864cf25cd..459d127c2 100644
--- a/src/core/loader/deconstructed_rom_directory.cpp
+++ b/src/core/loader/deconstructed_rom_directory.cpp
@@ -110,8 +110,6 @@ ResultStatus AppLoader_DeconstructedRomDirectory::Load(
         return ResultStatus::Error;
     }
 
-    process = Kernel::Process::Create("main");
-
     const std::string directory = filepath.substr(0, filepath.find_last_of("/\\")) + DIR_SEP;
     const std::string npdm_path = directory + DIR_SEP + "main.npdm";
 
@@ -121,13 +119,15 @@ ResultStatus AppLoader_DeconstructedRomDirectory::Load(
     }
     metadata.Print();
 
+    process = Kernel::Process::Create("main", metadata.GetTitleID());
+
     // Load NSO modules
     VAddr next_load_addr{Memory::PROCESS_IMAGE_VADDR};
     for (const auto& module : {"rtld", "main", "subsdk0", "subsdk1", "subsdk2", "subsdk3",
                                "subsdk4", "subsdk5", "subsdk6", "subsdk7", "sdk"}) {
         const std::string path = directory + DIR_SEP + module;
         const VAddr load_addr = next_load_addr;
-        next_load_addr = AppLoader_NSO::LoadModule(path, load_addr, metadata.GetTitleID());
+        next_load_addr = AppLoader_NSO::LoadModule(path, load_addr);
         if (next_load_addr) {
             LOG_DEBUG(Loader, "loaded module %s @ 0x%" PRIx64, module, load_addr);
         } else {
diff --git a/src/core/loader/elf.cpp b/src/core/loader/elf.cpp
index b87320656..cdd41f237 100644
--- a/src/core/loader/elf.cpp
+++ b/src/core/loader/elf.cpp
@@ -300,7 +300,7 @@ SharedPtr<CodeSet> ElfReader::LoadInto(u32 vaddr) {
     std::vector<u8> program_image(total_image_size);
     size_t current_image_position = 0;
 
-    SharedPtr<CodeSet> codeset = CodeSet::Create("", 0);
+    SharedPtr<CodeSet> codeset = CodeSet::Create("");
 
     for (unsigned int i = 0; i < header->e_phnum; ++i) {
         Elf32_Phdr* p = &segments[i];
@@ -406,7 +406,7 @@ ResultStatus AppLoader_ELF::Load(Kernel::SharedPtr<Kernel::Process>& process) {
     SharedPtr<CodeSet> codeset = elf_reader.LoadInto(Memory::PROCESS_IMAGE_VADDR);
     codeset->name = filename;
 
-    process = Kernel::Process::Create("main");
+    process = Kernel::Process::Create("main", 0);
     process->LoadModule(codeset, codeset->entrypoint);
     process->svc_access_mask.set();
     process->address_mappings = default_address_mappings;
diff --git a/src/core/loader/nro.cpp b/src/core/loader/nro.cpp
index 6f8a2f21e..c557b66dc 100644
--- a/src/core/loader/nro.cpp
+++ b/src/core/loader/nro.cpp
@@ -83,7 +83,7 @@ bool AppLoader_NRO::LoadNro(const std::string& path, VAddr load_base) {
     }
 
     // Build program image
-    Kernel::SharedPtr<Kernel::CodeSet> codeset = Kernel::CodeSet::Create("", 0);
+    Kernel::SharedPtr<Kernel::CodeSet> codeset = Kernel::CodeSet::Create("");
     std::vector<u8> program_image;
     program_image.resize(PageAlignSize(nro_header.file_size));
     file.Seek(0, SEEK_SET);
@@ -125,7 +125,7 @@ ResultStatus AppLoader_NRO::Load(Kernel::SharedPtr<Kernel::Process>& process) {
         return ResultStatus::Error;
     }
 
-    process = Kernel::Process::Create("main");
+    process = Kernel::Process::Create("main", 0);
 
     // Load NRO
     static constexpr VAddr base_addr{Memory::PROCESS_IMAGE_VADDR};
diff --git a/src/core/loader/nso.cpp b/src/core/loader/nso.cpp
index 7f8d24dd6..00b5d1d49 100644
--- a/src/core/loader/nso.cpp
+++ b/src/core/loader/nso.cpp
@@ -92,7 +92,7 @@ static constexpr u32 PageAlignSize(u32 size) {
     return (size + Memory::PAGE_MASK) & ~Memory::PAGE_MASK;
 }
 
-VAddr AppLoader_NSO::LoadModule(const std::string& path, VAddr load_base, u64 tid) {
+VAddr AppLoader_NSO::LoadModule(const std::string& path, VAddr load_base) {
     FileUtil::IOFile file(path, "rb");
     if (!file.IsOpen()) {
         return {};
@@ -109,7 +109,7 @@ VAddr AppLoader_NSO::LoadModule(const std::string& path, VAddr load_base, u64 ti
     }
 
     // Build program image
-    Kernel::SharedPtr<Kernel::CodeSet> codeset = Kernel::CodeSet::Create("", tid);
+    Kernel::SharedPtr<Kernel::CodeSet> codeset = Kernel::CodeSet::Create("");
     std::vector<u8> program_image;
     for (int i = 0; i < nso_header.segments.size(); ++i) {
         std::vector<u8> data =
@@ -155,10 +155,10 @@ ResultStatus AppLoader_NSO::Load(Kernel::SharedPtr<Kernel::Process>& process) {
         return ResultStatus::Error;
     }
 
-    process = Kernel::Process::Create("main");
+    process = Kernel::Process::Create("main", 0);
 
     // Load module
-    LoadModule(filepath, Memory::PROCESS_IMAGE_VADDR, 0);
+    LoadModule(filepath, Memory::PROCESS_IMAGE_VADDR);
     LOG_DEBUG(Loader, "loaded module %s @ 0x%" PRIx64, filepath.c_str(),
               Memory::PROCESS_IMAGE_VADDR);
 
diff --git a/src/core/loader/nso.h b/src/core/loader/nso.h
index 14eb1d87e..1ae30a824 100644
--- a/src/core/loader/nso.h
+++ b/src/core/loader/nso.h
@@ -29,7 +29,7 @@ public:
         return IdentifyType(file, filepath);
     }
 
-    static VAddr LoadModule(const std::string& path, VAddr load_base, u64 tid);
+    static VAddr LoadModule(const std::string& path, VAddr load_base);
 
     ResultStatus Load(Kernel::SharedPtr<Kernel::Process>& process) override;
 
diff --git a/src/tests/core/arm/arm_test_common.cpp b/src/tests/core/arm/arm_test_common.cpp
index 88bbbc95c..9296e1e94 100644
--- a/src/tests/core/arm/arm_test_common.cpp
+++ b/src/tests/core/arm/arm_test_common.cpp
@@ -15,7 +15,7 @@ static Memory::PageTable* page_table = nullptr;
 TestEnvironment::TestEnvironment(bool mutable_memory_)
     : mutable_memory(mutable_memory_), test_memory(std::make_shared<TestMemory>(this)) {
 
-    Kernel::g_current_process = Kernel::Process::Create("");
+    Kernel::g_current_process = Kernel::Process::Create("", 0);
     page_table = &Kernel::g_current_process->vm_manager.page_table;
 
     page_table->pointers.fill(nullptr);
diff --git a/src/tests/core/memory/memory.cpp b/src/tests/core/memory/memory.cpp
index 165496a54..0e0a43dcb 100644
--- a/src/tests/core/memory/memory.cpp
+++ b/src/tests/core/memory/memory.cpp
@@ -9,7 +9,7 @@
 
 TEST_CASE("Memory::IsValidVirtualAddress", "[core][memory][!hide]") {
     SECTION("these regions should not be mapped on an empty process") {
-        auto process = Kernel::Process::Create("");
+        auto process = Kernel::Process::Create("", 0);
         CHECK(Memory::IsValidVirtualAddress(*process, Memory::PROCESS_IMAGE_VADDR) == false);
         CHECK(Memory::IsValidVirtualAddress(*process, Memory::HEAP_VADDR) == false);
         CHECK(Memory::IsValidVirtualAddress(*process, Memory::LINEAR_HEAP_VADDR) == false);
@@ -20,14 +20,14 @@ TEST_CASE("Memory::IsValidVirtualAddress", "[core][memory][!hide]") {
     }
 
     SECTION("CONFIG_MEMORY_VADDR and SHARED_PAGE_VADDR should be valid after mapping them") {
-        auto process = Kernel::Process::Create("");
+        auto process = Kernel::Process::Create("", 0);
         Kernel::MapSharedPages(process->vm_manager);
         CHECK(Memory::IsValidVirtualAddress(*process, Memory::CONFIG_MEMORY_VADDR) == true);
         CHECK(Memory::IsValidVirtualAddress(*process, Memory::SHARED_PAGE_VADDR) == true);
     }
 
     SECTION("special regions should be valid after mapping them") {
-        auto process = Kernel::Process::Create("");
+        auto process = Kernel::Process::Create("", 0);
         SECTION("VRAM") {
             Kernel::HandleSpecialMapping(process->vm_manager,
                                          {Memory::VRAM_VADDR, Memory::VRAM_SIZE, false, false});
@@ -48,7 +48,7 @@ TEST_CASE("Memory::IsValidVirtualAddress", "[core][memory][!hide]") {
     }
 
     SECTION("Unmapping a VAddr should make it invalid") {
-        auto process = Kernel::Process::Create("");
+        auto process = Kernel::Process::Create("", 0);
         Kernel::MapSharedPages(process->vm_manager);
         process->vm_manager.UnmapRange(Memory::CONFIG_MEMORY_VADDR, Memory::CONFIG_MEMORY_SIZE);
         CHECK(Memory::IsValidVirtualAddress(*process, Memory::CONFIG_MEMORY_VADDR) == false);