From 547eabb403cf2f587b44548d567031ffd00d4499 Mon Sep 17 00:00:00 2001
From: Bananymous <bananymousosq@gmail.com>
Date: Thu, 28 Sep 2023 12:48:52 +0300
Subject: [PATCH] Kernel: Reboot will now always succeed

If acpi reset fails, we forcefully trigger a triple fault to restart
the system.
---
 kernel/arch/x86_64/IDT.cpp  | 10 ++++++++++
 kernel/include/kernel/IDT.h |  1 +
 kernel/kernel/Process.cpp   | 15 ++++++++++++++-
 3 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/kernel/arch/x86_64/IDT.cpp b/kernel/arch/x86_64/IDT.cpp
index 23f739c0..b7392734 100644
--- a/kernel/arch/x86_64/IDT.cpp
+++ b/kernel/arch/x86_64/IDT.cpp
@@ -424,4 +424,14 @@ namespace IDT
 		flush_idt();
 	}
 
+	[[noreturn]] void force_triple_fault()
+	{
+		// load 0 sized IDT and trigger an interrupt to force triple fault
+		asm volatile("cli");
+		s_idtr.size = 0;
+		flush_idt();
+		asm volatile("int $0x00");
+		ASSERT_NOT_REACHED();
+	}
+
 }
\ No newline at end of file
diff --git a/kernel/include/kernel/IDT.h b/kernel/include/kernel/IDT.h
index f69fb91a..679442e4 100644
--- a/kernel/include/kernel/IDT.h
+++ b/kernel/include/kernel/IDT.h
@@ -9,5 +9,6 @@ namespace IDT
 
 	void initialize();
 	void register_irq_handler(uint8_t irq, void(*f)());
+	[[noreturn]] void force_triple_fault();
 
 }
\ No newline at end of file
diff --git a/kernel/kernel/Process.cpp b/kernel/kernel/Process.cpp
index 1c196819..509ccdc0 100644
--- a/kernel/kernel/Process.cpp
+++ b/kernel/kernel/Process.cpp
@@ -3,6 +3,7 @@
 #include <kernel/CriticalScope.h>
 #include <kernel/FS/DevFS/FileSystem.h>
 #include <kernel/FS/VirtualFileSystem.h>
+#include <kernel/IDT.h>
 #include <kernel/InterruptController.h>
 #include <kernel/LockGuard.h>
 #include <kernel/Memory/Heap.h>
@@ -776,6 +777,18 @@ namespace Kernel
 		return 0;
 	}
 
+	[[noreturn]] static void reset_system()
+	{
+		lai_acpi_reset();
+
+		// acpi reset did not work
+
+		dwarnln("Could not reset with ACPI, crashing the cpu");
+
+		// reset through triple fault
+		IDT::force_triple_fault();
+	}
+
 	BAN::ErrorOr<long> Process::sys_poweroff(int command)
 	{
 		if (command != POWEROFF_REBOOT && command != POWEROFF_SHUTDOWN)
@@ -789,7 +802,7 @@ namespace Kernel
 		switch (command)
 		{
 			case POWEROFF_REBOOT:
-				error = lai_acpi_reset();
+				reset_system();
 				break;
 			case POWEROFF_SHUTDOWN:
 				error = lai_enter_sleep(5);