kernel: Eliminate kernel global state

As means to pave the way for getting rid of global state within core,
This eliminates kernel global state by removing all globals. Instead
this introduces a KernelCore class which acts as a kernel instance. This
instance lives in the System class, which keeps its lifetime contained
to the lifetime of the System class.

This also forces the kernel types to actually interact with the main
kernel instance itself instead of having transient kernel state placed
all over several translation units, keeping everything together. It also
has a nice consequence of making dependencies much more explicit.

This also makes our initialization a tad bit more correct. Previously we
were creating a kernel process before the actual kernel was initialized,
which doesn't really make much sense.

The KernelCore class itself follows the PImpl idiom, which allows
keeping all the implementation details sealed away from everything else,
which forces the use of the exposed API and allows us to avoid any
unnecessary inclusions within the main kernel header.

1 files changed, 12 insertions, 4 deletions

diff --git a/src/core/core.cpp b/src/core/core.cpp
index 07da4c493..2293669e5 100644
--- a/src/core/core.cpp
+++ b/src/core/core.cpp
@@ -171,6 +171,14 @@ const std::shared_ptr<Kernel::Scheduler>& System::Scheduler(size_t core_index) {
     return cpu_cores[core_index]->Scheduler();
 }
 
+Kernel::KernelCore& System::Kernel() {
+    return kernel;
+}
+
+const Kernel::KernelCore& System::Kernel() const {
+    return kernel;
+}
+
 ARM_Interface& System::ArmInterface(size_t core_index) {
     ASSERT(core_index < NUM_CPU_CORES);
     return cpu_cores[core_index]->ArmInterface();
@@ -185,12 +193,13 @@ System::ResultStatus System::Init(Frontend::EmuWindow& emu_window) {
     LOG_DEBUG(HW_Memory, "initialized OK");
 
     CoreTiming::Init();
+    kernel.Initialize();
 
     // Create a default fs if one doesn't already exist.
     if (virtual_filesystem == nullptr)
         virtual_filesystem = std::make_shared<FileSys::RealVfsFilesystem>();
 
-    current_process = Kernel::Process::Create("main");
+    current_process = Kernel::Process::Create(kernel, "main");
 
     cpu_barrier = std::make_shared<CpuBarrier>();
     cpu_exclusive_monitor = Cpu::MakeExclusiveMonitor(cpu_cores.size());
@@ -201,7 +210,6 @@ System::ResultStatus System::Init(Frontend::EmuWindow& emu_window) {
     telemetry_session = std::make_unique<Core::TelemetrySession>();
     service_manager = std::make_shared<Service::SM::ServiceManager>();
 
-    Kernel::Init();
     Service::Init(service_manager, virtual_filesystem);
     GDBStub::Init();
 
@@ -246,7 +254,6 @@ void System::Shutdown() {
     renderer.reset();
     GDBStub::Shutdown();
     Service::Shutdown();
-    Kernel::Shutdown();
     service_manager.reset();
     telemetry_session.reset();
     gpu_core.reset();
@@ -265,7 +272,8 @@ void System::Shutdown() {
     }
     cpu_barrier.reset();
 
-    // Close core timing
+    // Shutdown kernel and core timing
+    kernel.Shutdown();
     CoreTiming::Shutdown();
 
     // Close app loader