From da07e13e0798a4ebd423595830f04e2234a03942 Mon Sep 17 00:00:00 2001
From: Liam <byteslice@airmail.cc>
Date: Thu, 7 Jul 2022 12:34:46 -0400
Subject: kernel: fix single-core preemption points

---
 src/core/hle/kernel/k_scheduler.cpp | 13 +++++++++++++
 src/core/hle/kernel/k_scheduler.h   |  5 +----
 src/core/hle/kernel/k_thread.cpp    |  6 ------
 src/core/hle/kernel/k_thread.h      |  1 -
 4 files changed, 14 insertions(+), 11 deletions(-)

(limited to 'src/core/hle/kernel')

diff --git a/src/core/hle/kernel/k_scheduler.cpp b/src/core/hle/kernel/k_scheduler.cpp
index cac96a780..230ca3b95 100644
--- a/src/core/hle/kernel/k_scheduler.cpp
+++ b/src/core/hle/kernel/k_scheduler.cpp
@@ -103,7 +103,20 @@ void KScheduler::ScheduleOnInterrupt() {
     GetCurrentThread(kernel).EnableDispatch();
 }
 
+void KScheduler::PreemptSingleCore() {
+    GetCurrentThread(kernel).DisableDispatch();
+
+    auto* thread = GetCurrentThreadPointer(kernel);
+    auto& previous_scheduler = kernel.Scheduler(thread->GetCurrentCore());
+    previous_scheduler.Unload(thread);
+
+    Common::Fiber::YieldTo(thread->GetHostContext(), *m_switch_fiber);
+
+    GetCurrentThread(kernel).EnableDispatch();
+}
+
 void KScheduler::RescheduleCurrentCore() {
+    ASSERT(!kernel.IsPhantomModeForSingleCore());
     ASSERT(GetCurrentThread(kernel).GetDisableDispatchCount() == 1);
 
     GetCurrentThread(kernel).EnableDispatch();
diff --git a/src/core/hle/kernel/k_scheduler.h b/src/core/hle/kernel/k_scheduler.h
index 91e870933..ac7421c9a 100644
--- a/src/core/hle/kernel/k_scheduler.h
+++ b/src/core/hle/kernel/k_scheduler.h
@@ -49,6 +49,7 @@ public:
 
     void SetInterruptTaskRunnable();
     void RequestScheduleOnInterrupt();
+    void PreemptSingleCore();
 
     u64 GetIdleCount() {
         return m_state.idle_count;
@@ -62,10 +63,6 @@ public:
         return m_current_thread.load() == m_idle_thread;
     }
 
-    std::shared_ptr<Common::Fiber> GetSwitchFiber() {
-        return m_switch_fiber;
-    }
-
     KThread* GetPreviousThread() const {
         return m_state.prev_thread;
     }
diff --git a/src/core/hle/kernel/k_thread.cpp b/src/core/hle/kernel/k_thread.cpp
index d5d390f04..3640d1d13 100644
--- a/src/core/hle/kernel/k_thread.cpp
+++ b/src/core/hle/kernel/k_thread.cpp
@@ -1204,12 +1204,6 @@ KScopedDisableDispatch::~KScopedDisableDispatch() {
         return;
     }
 
-    // Skip the reschedule if single-core.
-    if (!Settings::values.use_multi_core.GetValue()) {
-        GetCurrentThread(kernel).EnableDispatch();
-        return;
-    }
-
     if (GetCurrentThread(kernel).GetDisableDispatchCount() <= 1) {
         auto scheduler = kernel.CurrentScheduler();
 
diff --git a/src/core/hle/kernel/k_thread.h b/src/core/hle/kernel/k_thread.h
index 1fc8f5f3e..9ee20208e 100644
--- a/src/core/hle/kernel/k_thread.h
+++ b/src/core/hle/kernel/k_thread.h
@@ -110,7 +110,6 @@ void SetCurrentThread(KernelCore& kernel, KThread* thread);
 [[nodiscard]] KThread* GetCurrentThreadPointer(KernelCore& kernel);
 [[nodiscard]] KThread& GetCurrentThread(KernelCore& kernel);
 [[nodiscard]] s32 GetCurrentCoreId(KernelCore& kernel);
-size_t CaptureBacktrace(void** buffer, size_t max);
 
 class KThread final : public KAutoObjectWithSlabHeapAndContainer<KThread, KWorkerTask>,
                       public boost::intrusive::list_base_hook<> {
-- 
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