From 89d74a908854371a5235557384bd30e29a2a918e Mon Sep 17 00:00:00 2001
From: Bananymous <oskari.alaranta@bananymous.com>
Date: Fri, 13 Oct 2023 14:14:05 +0300
Subject: [PATCH] Kernel: Separate scheduler execution and stack loading

Not sure if this is actually needed, but this allows actual
executing function to be in clean environment
---
 kernel/include/kernel/Scheduler.h |  1 +
 kernel/kernel/Scheduler.cpp       | 20 +++++++++++++++++++-
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/kernel/include/kernel/Scheduler.h b/kernel/include/kernel/Scheduler.h
index be813856..e03cdd02 100644
--- a/kernel/include/kernel/Scheduler.h
+++ b/kernel/include/kernel/Scheduler.h
@@ -31,6 +31,7 @@ namespace Kernel
 		static bool is_valid_tid(pid_t tid);
 
 		[[noreturn]] void execute_current_thread();
+		[[noreturn]] void _execute_current_thread();
 		[[noreturn]] void delete_current_process_and_thread();
 
 	private:
diff --git a/kernel/kernel/Scheduler.cpp b/kernel/kernel/Scheduler.cpp
index c33fda57..22ba59c2 100644
--- a/kernel/kernel/Scheduler.cpp
+++ b/kernel/kernel/Scheduler.cpp
@@ -7,7 +7,10 @@
 #include <kernel/Scheduler.h>
 #include <kernel/Timer/PIT.h>
 
-#if 1
+#define SCHEDULER_VERIFY_STACK 1
+#define SCHEDULER_VERIFY_INTERRUPT_STATE 1
+
+#if SCHEDULER_VERIFY_INTERRUPT_STATE
 	#define VERIFY_STI() ASSERT(interrupts_enabled())
 	#define VERIFY_CLI() ASSERT(!interrupts_enabled())
 #else
@@ -202,6 +205,7 @@ namespace Kernel
 		delete thread;
 
 		execute_current_thread();
+		ASSERT_NOT_REACHED();
 	}
 
 	void Scheduler::execute_current_thread()
@@ -210,6 +214,20 @@ namespace Kernel
 
 		load_temp_stack();
 		PageTable::kernel().load();
+		_execute_current_thread();
+		ASSERT_NOT_REACHED();
+	}
+
+	NEVER_INLINE void Scheduler::_execute_current_thread()
+	{
+		VERIFY_CLI();
+
+#if SCHEDULER_VERIFY_STACK
+		vaddr_t rsp;
+		read_rsp(rsp);
+		ASSERT((vaddr_t)s_temp_stack <= rsp && rsp <= (vaddr_t)s_temp_stack + sizeof(s_temp_stack));
+		ASSERT(&PageTable::current() == &PageTable::kernel());
+#endif
 
 		Thread* current = &current_thread();