From a1659aa1276dea990f44f7f4a0c9eb9b584fae65 Mon Sep 17 00:00:00 2001
From: apio <blobs.trading@gmail.com>
Date: Tue, 6 Sep 2022 11:47:55 +0200
Subject: [PATCH] Add a reboot() function

This reboot function first tries to reboot using ACPI, then pulsing the CPU's RESET line through the keyboard, then triple-faulting. If we're still there, it halts.
---
 kernel/include/power/reboot.h |  3 ++
 kernel/src/power/reboot.cpp   | 65 +++++++++++++++++++++++++++++++++++
 2 files changed, 68 insertions(+)
 create mode 100644 kernel/include/power/reboot.h
 create mode 100644 kernel/src/power/reboot.cpp

diff --git a/kernel/include/power/reboot.h b/kernel/include/power/reboot.h
new file mode 100644
index 00000000..e7de0de8
--- /dev/null
+++ b/kernel/include/power/reboot.h
@@ -0,0 +1,3 @@
+#pragma once
+
+[[noreturn]] void reboot();
\ No newline at end of file
diff --git a/kernel/src/power/reboot.cpp b/kernel/src/power/reboot.cpp
new file mode 100644
index 00000000..4ce87851
--- /dev/null
+++ b/kernel/src/power/reboot.cpp
@@ -0,0 +1,65 @@
+#include "power/reboot.h"
+#include "acpi/FADT.h"
+#include "acpi/RSDT.h"
+#include "assert.h"
+#include "interrupts/IDT.h"
+#include "interrupts/Interrupts.h"
+#include "io/IO.h"
+#include "log/Log.h"
+#include "panic/hang.h"
+#include "std/string.h"
+
+static void try_acpi_reboot()
+{
+    ACPI::SDTHeader* rootSDT = ACPI::GetRSDTOrXSDT();
+    if (!rootSDT) return;
+    if (!ACPI::ValidateSDTHeader(rootSDT)) return;
+    if (strncmp(rootSDT->Signature, "RSDT", 4) != 0 && strncmp(rootSDT->Signature, "XSDT", 4) != 0) return;
+    ACPI::FADT* fadt = (ACPI::FADT*)ACPI::FindTable(rootSDT, "FACP");
+    if (!fadt) return;
+    if (!ACPI::ValidateSDTHeader(&fadt->header)) return;
+    if (!(fadt->Flags & 1 << 10)) return;
+    switch (fadt->ResetReg.AddressSpace)
+    {
+    case ACPI::SystemIO: IO::outb(fadt->ResetReg.Address, fadt->ResetValue); break;
+    case ACPI::GeneralPurposeIO: IO::outb(fadt->ResetReg.Address, fadt->ResetValue); break;
+    default: return;
+    }
+}
+
+static void try_kbd_reboot()
+{
+    Interrupts::disable();
+
+    uint8_t temp;
+    do {
+        temp = IO::inb(0x64);
+        if (temp & 0b1) IO::inb(0x60);
+    } while (temp & 0b10);
+
+    IO::outb(0x64, 0xFE);
+}
+
+static void try_idt_triple_fault()
+{
+    IDTR idtr;
+    idtr.limit = 0x0000;
+    idtr.offset = 0x0000;
+    asm volatile("lidt %0" : : "m"(idtr));
+    Interrupts::enable();
+    asm volatile("int $0x80");
+}
+
+[[noreturn]] void reboot()
+{
+    kinfoln("Attempting reboot using ACPI");
+    try_acpi_reboot();
+    kinfoln("Attempting reboot using keyboard RESET pulsing");
+    try_kbd_reboot();
+    kinfoln("Attempting reboot by triple faulting");
+    try_idt_triple_fault();
+    kerrorln("Failed to reboot, halting machine");
+    hang();
+end:
+    goto end;
+}
\ No newline at end of file