[WIP] Basic Userspace

README.md

@@ -70,8 +70,9 @@ Much thanks to:
    - Omarrx024, 
    - [Mintsuki](https://github.com/mintsuki), 
    - [Korona](https://github.com/avdgrinten), 
+   - [Qookie](https://gitlab.com/qookei),
    - and [Safsom](https://github.com/asfsom);
- - the people part of the [rust-osdev](https://github.com/rust-osdev), such as
+ - the people part of the [rust-osdev](https://github.com/rust-osdev) organisation, such as
    - [Isaac Woods](https://github.com/IsaacWoods);
  - the [OsDev wiki](http://wiki.osdev.org);
  - [Bare Metal Rust](http://www.randomhacks.net/bare-metal-rust/);

kernel/Cargo.toml

@@ -22,17 +22,16 @@ bitflags = "^1.0.1"
 bit_field = "^0.9.0"
 log = "^0.4.3"
 static_assertions = "^0.2.5"
+acpi = "0.2"
 
 [dependencies.x86_64]
-path = "../../x86_64/"
+git = "https://github.com/Restioson/x86_64"
+branch = "gdt"
 
 [dependencies.multiboot2]
 git = "https://github.com/rust-osdev/multiboot2-elf64/"
 rev = "9ce9247eee220a0bc2ca480c23c7572132c5ae9c"
 
-[dependencies.acpi]
-version = "0.2"
-
 [dependencies.arrayvec]
 version = "^0.4.7"
 default-features = false

kernel/src/gdt.rs

@@ -1,12 +1,14 @@
-use core::cell::RefCell;
+use core::{ops::Range, cell::RefCell};
 use spin::{Once, Mutex};
 use x86_64::structures::tss::TaskStateSegment;
+use bit_field::BitField;
+use crate::serial::PORT_1_ADDR;
 
 pub const DOUBLE_FAULT_IST_INDEX: u16 = 0;
 pub const PANICKING_EXCEPTION_IST_INDEX: u16 = 1;
 pub const IRQ_IST_INDEX: u16 = 2;
 
-pub static TSS: Once<Mutex<RefCell<TaskStateSegment>>> = Once::new();
+pub static TSS: Once<Mutex<Tss>> = Once::new();
 
 use x86_64::structures::gdt::{GlobalDescriptorTable, Descriptor, DescriptorFlags as Flags,
                               SegmentSelector};
@@ -20,9 +22,9 @@ lazy_static! {
             (Flags::USER_SEGMENT | Flags::PRESENT).bits() | (1 << 41),
         ));
 
-        let tss = unsafe {
-            gdt.add_entry(Descriptor::tss_segment(&*TSS.wait().unwrap().lock().as_ptr()))
-        };
+        let tss = unsafe { gdt.add_entry(
+            Descriptor::tss_segment(&*TSS.wait().unwrap().lock().tss.as_ptr(), 8193)
+        )};
 
         let user_cs = gdt.add_entry(Descriptor::UserSegment(
             (Flags::USER_SEGMENT | Flags::PRESENT | Flags::EXECUTABLE | Flags::LONG_MODE).bits()
@@ -52,6 +54,51 @@ struct Selectors {
     tss: SegmentSelector,
 }
 
+#[repr(C)]
+pub struct Tss {
+    pub tss: RefCell<TaskStateSegment>,
+    iomap: [u8; 8193],
+}
+
+impl Tss {
+    pub fn new(tss: TaskStateSegment) -> Self {
+        let mut tss = Tss {
+            tss: RefCell::new(tss),
+            iomap: [0xff; 8193],
+        };
+
+        // Absolute values don't matter, only the difference
+        let tss_addr = tss.tss.as_ptr() as usize;
+        let iomap_addr = (&tss.iomap) as *const _ as usize;
+        let iomap_base = (iomap_addr - tss_addr) as u16;
+
+        tss.tss.get_mut().iomap_base = iomap_base;
+
+        tss
+    }
+
+    pub fn set_ports_usable(&mut self, ports: Range<u16>, usable: bool) {
+        assert!(ports.end / 8 < 8192, "Port 0x{:x} out of bounds", ports.end);
+
+        // TODO could be optimised
+        for port in ports {
+            let byte_idx = port / 8;
+            let bit = port % 8;
+            // For some reason 1 = disabled
+            self.iomap[byte_idx as usize].set_bit(bit as usize, !usable);
+        }
+    }
+
+    pub fn is_port_usable(&self, port: u16) -> bool {
+        assert!(port / 8 < 8192, "Port 0x{:x} out of bounds", port);
+
+        let byte_idx = port / 8;
+        let bit = port % 8;
+        // For some reason 1 = disabled
+        !self.iomap[byte_idx as usize].get_bit(bit as usize)
+    }
+}
+
 pub fn init() {
     use x86_64::instructions::segmentation::*;
     use x86_64::instructions::tables::load_tss;
@@ -78,5 +125,8 @@ pub fn init() {
     trace!("user cs = 0x{:x}", GDT.selectors.user_cs.0);
     trace!("user ds = 0x{:x}", GDT.selectors.user_ds.0);
 
+
+    TSS.wait().unwrap().lock().set_ports_usable(PORT_1_ADDR..PORT_1_ADDR + 8, true);
+    trace!("port enabled: {:?}", TSS.wait().unwrap().lock().is_port_usable(PORT_1_ADDR));
     debug!("gdt: initialised");
 }

kernel/src/memory/mod.rs

@@ -35,7 +35,7 @@ use self::bootstrap_heap::{BootstrapHeap, BOOTSTRAP_HEAP};
 use self::paging::{Page, PageSize, PhysicalAddress, VirtualAddress, PAGE_TABLES, EntryFlags,
                    PageRangeMapping, remap, InvalidateTlb};
 use crate::util::round_up_divide;
-use crate::gdt;
+use crate::gdt::{TSS, Tss};
 
 pub const KERNEL_MAPPING_BEGIN: usize = 0xffffffff80000000;
 const IST_STACK_SIZE_PAGES: usize = 3;
@@ -134,7 +134,7 @@ unsafe fn setup_ist(begin: Page) {
         }
     }
 
-    gdt::TSS.call_once(|| {
+    TSS.call_once(|| {
         let mut tss = TaskStateSegment::new();
 
         for i in 0..7 { // Packed struct; cannot safely borrow fields
@@ -144,7 +144,7 @@ unsafe fn setup_ist(begin: Page) {
             tss.interrupt_stack_table[i] = x86_64::VirtAddr::new(stack_end);
         }
 
-        Mutex::new(RefCell::new(tss))
+        Mutex::new(Tss::new(tss))
     });
 }
 

kernel/src/userspace.rs

@@ -20,7 +20,7 @@ pub unsafe fn jump_usermode() -> ! {
     let rsp: u64;
     asm!("mov %rsp, $0" : "=r"(rsp));
 
-    crate::gdt::TSS.wait().unwrap().lock().get_mut().privilege_stack_table[0] = VirtAddr::new(rsp);
+    crate::gdt::TSS.wait().unwrap().lock().tss.get_mut().privilege_stack_table[0] = VirtAddr::new(rsp);
 
     asm!("
     push 0x2b

serial.log

@@ -48,6 +48,7 @@ Flower kernel boot!
 [trace] kernel ds = 0x10
 [trace] user cs = 0x2b
 [trace] user ds = 0x33
+[trace] port enabled: false
 [debug] gdt: initialised
 [info]  interrupts: initializing
 [debug] interrupts: initialized idt
@@ -56,9 +57,9 @@ Flower kernel boot!
 [info]  interrupts: ready
 Panicked at "cpuex: general protection fault 0x0
 InterruptStackFrame {
-    instruction_pointer: VirtAddr(0xffffffff8010e31a),
+    instruction_pointer: VirtAddr(0xffffffff8010156a),
     code_segment: 43,
     cpu_flags: 0x202,
-    stack_pointer: VirtAddr(0xffffffff80374e38),
+    stack_pointer: VirtAddr(0xffffffff8036fe68),
     stack_segment: 51,
 }", src/interrupts/exceptions.rs:73