From 1bcc7f96f42be809792baaf22b487901e4c9d36f Mon Sep 17 00:00:00 2001
From: Jeremy Soller <jackpot51@gmail.com>
Date: Wed, 28 Dec 2016 17:21:16 -0700
Subject: [PATCH] Parse FADT

---
 arch/x86_64/src/acpi/fadt.rs | 96 ++++++++++++++++++++++++++++++++++++
 arch/x86_64/src/acpi/mod.rs  |  6 ++-
 arch/x86_64/src/lib.rs       |  3 ++
 arch/x86_64/src/stop.rs      | 23 +++++++++
 4 files changed, 127 insertions(+), 1 deletion(-)
 create mode 100644 arch/x86_64/src/acpi/fadt.rs
 create mode 100644 arch/x86_64/src/stop.rs

diff --git a/arch/x86_64/src/acpi/fadt.rs b/arch/x86_64/src/acpi/fadt.rs
new file mode 100644
index 0000000..d40d5a1
--- /dev/null
+++ b/arch/x86_64/src/acpi/fadt.rs
@@ -0,0 +1,96 @@
+use core::{mem, ptr};
+
+use super::sdt::Sdt;
+
+#[repr(packed)]
+#[derive(Debug)]
+pub struct Fadt {
+    pub header: Sdt,
+    pub firmware_ctrl: u32,
+    pub dsdt: u32,
+
+    // field used in ACPI 1.0; no longer in use, for compatibility only
+    reserved: u8,
+
+    pub preferred_power_managament: u8,
+    pub sci_interrupt: u16,
+    pub smi_command_port: u32,
+    pub acpi_enable: u8,
+    pub acpi_disable: u8,
+    pub s4_bios_req: u8,
+    pub pstate_control: u8,
+    pub pm1a_event_block: u32,
+    pub pm1b_event_block: u32,
+    pub pm1a_control_block: u32,
+    pub pm1b_control_block: u32,
+    pub pm2_control_block: u32,
+    pub pm_timer_block: u32,
+    pub gpe0_block: u32,
+    pub gpe1_block: u32,
+    pub pm1_event_length: u8,
+    pub pm1_control_length: u8,
+    pub pm2_control_length: u8,
+    pub pm_timer_length: u8,
+    pub gpe0_ength: u8,
+    pub gpe1_length: u8,
+    pub gpe1_base: u8,
+    pub c_state_control: u8,
+    pub worst_c2_latency: u16,
+    pub worst_c3_latency: u16,
+    pub flush_size: u16,
+    pub flush_stride: u16,
+    pub duty_offset: u8,
+    pub duty_width: u8,
+    pub day_alarm: u8,
+    pub month_alarm: u8,
+    pub century: u8,
+
+    // reserved in ACPI 1.0; used since ACPI 2.0+
+    pub boot_architecture_flags: u16,
+
+    reserved2: u8,
+    pub flags: u32,
+}
+
+/* ACPI 2 structure
+#[repr(packed)]
+#[derive(Clone, Copy, Debug, Default)]
+pub struct GenericAddressStructure {
+    address_space: u8,
+    bit_width: u8,
+    bit_offset: u8,
+    access_size: u8,
+    address: u64,
+}
+
+{
+    // 12 byte structure; see below for details
+    pub reset_reg: GenericAddressStructure,
+
+    pub reset_value: u8,
+    reserved3: [u8; 3],
+
+    // 64bit pointers - Available on ACPI 2.0+
+    pub x_firmware_control: u64,
+    pub x_dsdt: u64,
+
+    pub x_pm1a_event_block: GenericAddressStructure,
+    pub x_pm1b_event_block: GenericAddressStructure,
+    pub x_pm1a_control_block: GenericAddressStructure,
+    pub x_pm1b_control_block: GenericAddressStructure,
+    pub x_pm2_control_block: GenericAddressStructure,
+    pub x_pm_timer_block: GenericAddressStructure,
+    pub x_gpe0_block: GenericAddressStructure,
+    pub x_gpe1_block: GenericAddressStructure,
+}
+*/
+
+impl Fadt {
+    pub fn new(sdt: &'static Sdt) -> Option<Fadt> {
+        if &sdt.signature == b"FACP" && sdt.length as usize >= mem::size_of::<Fadt>() {
+            Some(unsafe { ptr::read((sdt as *const Sdt) as *const Fadt) })
+        } else {
+            None
+        }
+    }
+}
diff --git a/arch/x86_64/src/acpi/mod.rs b/arch/x86_64/src/acpi/mod.rs
index 8411f1c..87f4416 100644
--- a/arch/x86_64/src/acpi/mod.rs
+++ b/arch/x86_64/src/acpi/mod.rs
@@ -11,12 +11,14 @@ use paging::{entry, ActivePageTable, Page, PhysicalAddress, VirtualAddress};
 use start::{kstart_ap, CPU_COUNT, AP_READY};
 
 use self::dmar::{Dmar, DmarEntry};
+use self::fadt::Fadt;
 use self::madt::{Madt, MadtEntry};
 use self::rsdt::Rsdt;
 use self::sdt::Sdt;
 use self::xsdt::Xsdt;
 
 pub mod dmar;
+pub mod fadt;
 pub mod madt;
 pub mod rsdt;
 pub mod sdt;
@@ -31,7 +33,9 @@ pub fn init_sdt(sdt: &'static Sdt, active_table: &mut ActivePageTable) {
         print!("{}", c as char);
     }
 
-    if let Some(madt) = Madt::new(sdt) {
+    if let Some(fadt) = Fadt::new(sdt) {
+        println!(": {:#?}", fadt);
+    } else if let Some(madt) = Madt::new(sdt) {
         println!(": {:>08X}: {}", madt.local_address, madt.flags);
 
         let mut local_apic = unsafe { &mut LOCAL_APIC };
diff --git a/arch/x86_64/src/lib.rs b/arch/x86_64/src/lib.rs
index 21be1a1..dc30d69 100644
--- a/arch/x86_64/src/lib.rs
+++ b/arch/x86_64/src/lib.rs
@@ -316,5 +316,8 @@ pub mod panic;
 /// Initialization and start function
 pub mod start;
 
+/// Shutdown function
+pub mod stop;
+
 /// Time
 pub mod time;
diff --git a/arch/x86_64/src/stop.rs b/arch/x86_64/src/stop.rs
new file mode 100644
index 0000000..5af92ae
--- /dev/null
+++ b/arch/x86_64/src/stop.rs
@@ -0,0 +1,23 @@
+use io::{Io, Pio};
+
+#[no_mangle]
+pub unsafe extern fn kstop() -> ! {
+    // (phony) ACPI shutdown (http://forum.osdev.org/viewtopic.php?t=16990)
+    // Works for qemu and bochs.
+    for &port in [0x604, 0xB004].iter() {
+        println!("Shutdown with outw(0x{:X}, 0x{:X})", port, 0x2000);
+        Pio::<u16>::new(port).write(0x2000);
+    }
+
+    // Magic shutdown code for bochs and qemu (older versions).
+    for c in "Shutdown".bytes() {
+        println!("Shutdown with outb(0x{:X}, '{}')", 0x8900, c as char);
+        Pio::<u8>::new(0x8900).write(c);
+    }
+
+    // Magic code for VMWare. Also a hard lock.
+    println!("Shutdown with cli hlt");
+    asm!("cli; hlt" : : : : "intel", "volatile");
+
+    unreachable!();
+}