AA

Cargo.lock

@@ -124,6 +124,15 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "ramfs"
+version = "0.1.0"
+dependencies = [
+ "error",
+ "spin",
+ "vfs",
+]
+
 [[package]]
 name = "rustc_version"
 version = "0.2.3"
@@ -191,3 +200,11 @@ name = "unsafe_unwrap"
 version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1230ec65f13e0f9b28d789da20d2d419511893ea9dac2c1f4ef67b8b14e5da80"
+
+[[package]]
+name = "vfs"
+version = "0.1.0"
+dependencies = [
+ "error",
+ "spin",
+]

Cargo.toml

@@ -7,5 +7,7 @@ edition = "2018"
 members = [
     "kernel",
     "error",
-    "address"
+    "address",
+    "fs/vfs",
+    "fs/ramfs"
 ]

build.sh

@@ -4,10 +4,19 @@ if [ -z "${MACH}" ]; then
     MACH=rpi3b
 fi
 
+if [ -z "${PROFILE}" ]; then
+    PROFILE=debug
+fi
+
 LLVM_DIR=$(llvm-config --bindir)
 ARCH=aarch64-unknown-none-${MACH}
+CARGO_FEATURES="mach_$MACH"
 CARGO_ARGS="--target ../etc/aarch64-unknown-none-$MACH.json \
-            --features mach_$MACH,fdt-rs"
+            --features $CARGO_FEATURES"
+
+if [ "$PROFILE" = "release" ]; then
+    CARGO_ARGS="$CARGO_ARGS --release"
+fi
 
 set -e
 
@@ -21,4 +30,5 @@ case $1 in
         ;;
 esac
 cd ..
-${LLVM_DIR}/llvm-objcopy -O binary target/${ARCH}/debug/kernel target/${ARCH}/debug/kernel.bin
+${LLVM_DIR}/llvm-objcopy -O binary target/${ARCH}/${PROFILE}/kernel \
+                                   target/${ARCH}/${PROFILE}/kernel.bin

error/src/lib.rs

@@ -2,5 +2,8 @@
 
 #[derive(PartialEq, Debug, Clone, Copy)]
 pub enum Errno {
-    OutOfMemory
+    InvalidArgument,
+    DoesNotExist,
+    NotADirectory,
+    OutOfMemory,
 }

fs/ramfs/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "ramfs"
+version = "0.1.0"
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+spin = "*"
+vfs = { path = "../vfs" }
+error = { path = "../../error" }

fs/ramfs/src/block.rs

@@ -0,0 +1,146 @@
+use core::mem::{size_of, MaybeUninit};
+use core::ops::{Deref, DerefMut};
+use error::Errno;
+
+pub const SIZE: usize = 4096;
+pub const ENTRY_COUNT: usize = SIZE / size_of::<usize>();
+
+pub trait BlockAllocator {
+    fn alloc(&self) -> *mut u8;
+    unsafe fn free(&self, ptr: *mut u8);
+}
+
+pub struct BlockRef<'a, A: BlockAllocator + Copy> {
+    inner: Option<&'a mut [u8; SIZE]>,
+    alloc: MaybeUninit<A>,
+}
+
+impl<'a, A: BlockAllocator + Copy> BlockRef<'a, A> {
+    pub fn new(alloc: A) -> Result<Self, Errno> {
+        assert!(size_of::<A>() == 0);
+        let ptr = alloc.alloc();
+        if ptr.is_null() {
+            Err(Errno::OutOfMemory)
+        } else {
+            Ok(unsafe { Self::from_raw(alloc, ptr) })
+        }
+    }
+
+    pub fn new_indirect(alloc: A) -> Result<Self, Errno> {
+        let mut res = Self::new(alloc)?;
+        for it in res.as_mut_ref_array().iter_mut() {
+            it.write(BlockRef::null());
+        }
+        Ok(res)
+    }
+
+    pub fn null() -> Self {
+        Self {
+            inner: None,
+            alloc: MaybeUninit::uninit(),
+        }
+    }
+
+    pub unsafe fn from_raw(alloc: A, data: *mut u8) -> Self {
+        Self {
+            inner: Some(&mut *(data as *mut _)),
+            alloc: MaybeUninit::new(alloc),
+        }
+    }
+
+    pub fn is_null(&self) -> bool {
+        self.inner.is_none()
+    }
+
+    pub fn as_mut_ref_array(&mut self) -> &mut [MaybeUninit<BlockRef<'a, A>>; ENTRY_COUNT] {
+        assert_eq!(size_of::<Self>(), 8);
+        unsafe { &mut *(self.deref_mut() as *mut _ as *mut _) }
+    }
+
+    pub fn as_ref_array(&self) -> &[MaybeUninit<BlockRef<'a, A>>; ENTRY_COUNT] {
+        assert_eq!(size_of::<Self>(), 8);
+        unsafe { &*(self.deref() as *const _ as *const _) }
+    }
+
+    pub fn zero(&mut self) {
+        if let Some(inner) = self.inner.as_mut() {
+            inner.fill(0);
+        } else {
+            panic!("Tried to fill a NULL blockref");
+        }
+    }
+}
+
+impl<'a, A: BlockAllocator + Copy> Drop for BlockRef<'a, A> {
+    fn drop(&mut self) {
+        if let Some(inner) = self.inner.take() {
+            unsafe {
+                self.alloc.assume_init_ref().free(inner as *mut _ as *mut _);
+            }
+        }
+    }
+}
+
+impl<'a, A: BlockAllocator + Copy> Deref for BlockRef<'a, A> {
+    type Target = [u8; SIZE];
+
+    fn deref(&self) -> &Self::Target {
+        self.inner.as_ref().unwrap()
+    }
+}
+
+impl<'a, A: BlockAllocator + Copy> DerefMut for BlockRef<'a, A> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        self.inner.as_mut().unwrap()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::boxed::Box;
+    use std::sync::atomic::{AtomicUsize, Ordering};
+
+    static A_COUNTER: AtomicUsize = AtomicUsize::new(0);
+
+    #[test]
+    fn block_allocator() {
+        #[derive(Clone, Copy)]
+        struct A;
+        impl BlockAllocator for A {
+            fn alloc(&self) -> *mut u8 {
+                let b = Box::leak(Box::<[u8; SIZE]>::new_uninit());
+                A_COUNTER.fetch_add(1, Ordering::SeqCst);
+                b.as_mut_ptr() as *mut _
+            }
+
+            unsafe fn free(&self, ptr: *mut u8) {
+                A_COUNTER.fetch_sub(1, Ordering::SeqCst);
+                drop(Box::from_raw(ptr as *mut [u8; SIZE]));
+            }
+        }
+
+        const N: usize = 13;
+        {
+            let mut s: [MaybeUninit<BlockRef<A>>; N] = MaybeUninit::uninit_array();
+
+            assert_eq!(A_COUNTER.load(Ordering::Acquire), 0);
+
+            for i in 0..N {
+                let mut block = BlockRef::new(A {}).unwrap();
+                block.fill(1);
+                s[i].write(block);
+            }
+
+            assert_eq!(A_COUNTER.load(Ordering::Acquire), N);
+
+            for i in 0..N {
+                unsafe {
+                    s[i].assume_init_drop();
+                }
+            }
+
+            assert_eq!(A_COUNTER.load(Ordering::Acquire), 0);
+        }
+    }
+}

fs/ramfs/src/bvec.rs

@@ -0,0 +1,691 @@
+use crate::{block, BlockAllocator, BlockRef};
+use core::cmp::{max, min};
+use core::marker::PhantomData;
+use core::mem::MaybeUninit;
+use core::ops::{Index, IndexMut};
+use error::Errno;
+
+const L0_BLOCKS: usize = 32; // 128K
+const L1_BLOCKS: usize = 8; // 16M
+
+pub struct Bvec<'a, A: BlockAllocator + Copy> {
+    capacity: usize,
+    size: usize,
+    l0: [MaybeUninit<BlockRef<'a, A>>; L0_BLOCKS],
+    l1: [MaybeUninit<BlockRef<'a, A>>; L1_BLOCKS],
+    l2: MaybeUninit<BlockRef<'a, A>>,
+    alloc: A,
+}
+
+impl<'a, A: BlockAllocator + Copy> Bvec<'a, A> {
+    pub fn new(alloc: A) -> Self {
+        let mut res = Self {
+            capacity: 0,
+            size: 0,
+            l0: MaybeUninit::uninit_array(),
+            l1: MaybeUninit::uninit_array(),
+            l2: MaybeUninit::uninit(),
+            alloc,
+        };
+        for it in res.l0.iter_mut() {
+            it.write(BlockRef::null());
+        }
+        for it in res.l1.iter_mut() {
+            it.write(BlockRef::null());
+        }
+        res.l2.write(BlockRef::null());
+        res
+    }
+
+    pub fn resize(&mut self, cap: usize) -> Result<(), Errno> {
+        if cap <= self.capacity {
+            let mut curr = self.capacity;
+            while curr != cap {
+                curr -= 1;
+                let mut index = curr;
+
+                if index >= L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT {
+                    index -= L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT;
+
+                    let l1i = index / block::ENTRY_COUNT;
+                    let l0i = index % block::ENTRY_COUNT;
+
+                    let l2r = unsafe { self.l2.assume_init_mut() };
+                    assert!(!l2r.is_null());
+                    let l1r = unsafe { l2r.as_mut_ref_array()[l1i].assume_init_mut() };
+                    assert!(!l1r.is_null());
+                    let l0r = unsafe { l1r.as_mut_ref_array()[l0i].assume_init_mut() };
+                    assert!(!l0r.is_null());
+
+                    *l0r = BlockRef::null();
+                    if l0i == 0 {
+                        *l1r = BlockRef::null();
+                    }
+                    if index == 0 {
+                        *l2r = BlockRef::null();
+                    }
+                    continue;
+                }
+
+                if index >= L0_BLOCKS {
+                    index -= L0_BLOCKS;
+
+                    let l1i = index / block::ENTRY_COUNT;
+                    let l0i = index % block::ENTRY_COUNT;
+
+                    let l1r = unsafe { self.l1[l1i].assume_init_mut() };
+                    assert!(!l1r.is_null());
+                    let l0r = unsafe { l1r.as_mut_ref_array()[l0i].assume_init_mut() };
+                    assert!(!l0r.is_null());
+
+                    *l0r = BlockRef::null();
+                    if l0i == 0 {
+                        *l1r = BlockRef::null();
+                    }
+
+                    continue;
+                }
+
+                let l0r = unsafe { self.l0[index].assume_init_mut() };
+                assert!(!l0r.is_null());
+                *l0r = BlockRef::null();
+                continue;
+
+                unimplemented!();
+            }
+        } else {
+            for mut index in self.capacity..cap {
+                if index < L0_BLOCKS {
+                    let l0r = unsafe { self.l0[index].assume_init_mut() };
+                    assert!(l0r.is_null());
+                    *l0r = BlockRef::new(self.alloc)?;
+                    continue;
+                }
+                index -= L0_BLOCKS;
+                if index < L1_BLOCKS * block::ENTRY_COUNT {
+                    let l1i = index / block::ENTRY_COUNT;
+                    let l0i = index % block::ENTRY_COUNT;
+
+                    let l1r = unsafe { self.l1[l1i].assume_init_mut() };
+                    if l1r.is_null() {
+                        *l1r = BlockRef::new_indirect(self.alloc)?;
+                    }
+
+                    let l0r = unsafe { l1r.as_mut_ref_array()[l0i].assume_init_mut() };
+                    assert!(l0r.is_null());
+                    *l0r = BlockRef::new(self.alloc)?;
+
+                    continue;
+                }
+                index -= L1_BLOCKS * block::ENTRY_COUNT;
+                if index < block::ENTRY_COUNT * block::ENTRY_COUNT {
+                    let l1i = index / block::ENTRY_COUNT;
+                    let l0i = index % block::ENTRY_COUNT;
+
+                    let l2r = unsafe { self.l2.assume_init_mut() };
+                    if l2r.is_null() {
+                        *l2r = BlockRef::new_indirect(self.alloc)?;
+                    }
+
+                    let l1r = unsafe { l2r.as_mut_ref_array()[l1i].assume_init_mut() };
+                    if l1r.is_null() {
+                        *l1r = BlockRef::new_indirect(self.alloc)?;
+                    }
+
+                    let l0r = unsafe { l1r.as_mut_ref_array()[l0i].assume_init_mut() };
+                    assert!(l0r.is_null());
+                    *l0r = BlockRef::new(self.alloc)?;
+
+                    continue;
+                }
+                unimplemented!();
+            }
+        }
+
+        self.capacity = cap;
+        Ok(())
+    }
+
+    pub fn write(&mut self, mut pos: usize, data: &[u8]) -> Result<usize, Errno> {
+        if pos > self.size {
+            return Err(Errno::InvalidArgument);
+        }
+
+        let mut rem = data.len();
+        let mut doff = 0usize;
+
+        if pos + rem > self.size {
+            self.size = pos + rem;
+            self.resize((pos + rem + block::SIZE - 1) / block::SIZE)?;
+        }
+
+        while rem > 0 {
+            let index = pos / block::SIZE;
+            let off = pos % block::SIZE;
+            let count = min(block::SIZE - off, rem);
+
+            let block = &mut self[index];
+
+            let dst = &mut block[off..off + count];
+            let src = &data[doff..doff + count];
+            dst.copy_from_slice(src);
+
+            doff += count;
+            pos += count;
+            rem -= count;
+        }
+
+        Ok(doff)
+    }
+
+    pub fn read(&self, mut pos: usize, data: &mut [u8]) -> Result<usize, Errno> {
+        if pos > self.size {
+            return Err(Errno::InvalidArgument);
+        }
+
+        let mut rem = min(self.size - pos, data.len());
+        let mut doff = 0usize;
+
+        while rem > 0 {
+            let index = pos / block::SIZE;
+            let off = pos % block::SIZE;
+            let count = min(block::SIZE - off, rem);
+
+            let block = &self[index];
+
+            let src = &block[off..off + count];
+            let dst = &mut data[doff..doff + count];
+            dst.copy_from_slice(src);
+
+            doff += count;
+            pos += count;
+            rem -= count;
+        }
+
+        Ok(doff)
+    }
+}
+
+impl<'a, A: BlockAllocator + Copy> Index<usize> for Bvec<'a, A> {
+    type Output = BlockRef<'a, A>;
+    fn index(&self, mut index: usize) -> &Self::Output {
+        if index >= self.capacity {
+            panic!(
+                "Index exceeds bvec capacity ({} >= {})",
+                index, self.capacity
+            );
+        }
+
+        if index < L0_BLOCKS {
+            return unsafe { self.l0[index].assume_init_ref() };
+        }
+        index -= L0_BLOCKS;
+        if index < L1_BLOCKS * block::ENTRY_COUNT {
+            return unsafe {
+                let l1 = self.l1[index / block::ENTRY_COUNT].assume_init_ref();
+                l1.as_ref_array()[index % block::ENTRY_COUNT].assume_init_ref()
+            };
+        }
+        index -= L1_BLOCKS * block::ENTRY_COUNT;
+        if index < block::ENTRY_COUNT * block::ENTRY_COUNT {
+            return unsafe {
+                let l2 = self.l2.assume_init_ref();
+                let l1 = l2.as_ref_array()[index / block::ENTRY_COUNT].assume_init_ref();
+                l1.as_ref_array()[index % block::ENTRY_COUNT].assume_init_ref()
+            };
+        }
+        unimplemented!();
+    }
+}
+
+impl<'a, A: BlockAllocator + Copy> IndexMut<usize> for Bvec<'a, A> {
+    fn index_mut(&mut self, mut index: usize) -> &mut Self::Output {
+        if index >= self.capacity {
+            panic!(
+                "Index exceeds bvec capacity ({} >= {})",
+                index, self.capacity
+            );
+        }
+
+        if index < L0_BLOCKS {
+            return unsafe { self.l0[index].assume_init_mut() };
+        }
+        index -= L0_BLOCKS;
+        if index < L1_BLOCKS * block::ENTRY_COUNT {
+            return unsafe {
+                let l1 = self.l1[index / block::ENTRY_COUNT].assume_init_mut();
+                l1.as_mut_ref_array()[index % block::ENTRY_COUNT].assume_init_mut()
+            };
+        }
+        index -= L1_BLOCKS * block::ENTRY_COUNT;
+        if index < block::ENTRY_COUNT * block::ENTRY_COUNT {
+            return unsafe {
+                let l2 = self.l2.assume_init_mut();
+                let l1 = l2.as_mut_ref_array()[index / block::ENTRY_COUNT].assume_init_mut();
+                l1.as_mut_ref_array()[index % block::ENTRY_COUNT].assume_init_mut()
+            };
+        }
+        unimplemented!();
+    }
+}
+
+impl<'a, A: BlockAllocator + Copy> Drop for Bvec<'a, A> {
+    fn drop(&mut self) {
+        for i in 0..min(L0_BLOCKS, self.capacity) {
+            unsafe {
+                self.l0[i].assume_init_drop();
+            }
+        }
+        if self.capacity > L0_BLOCKS {}
+    }
+}
+
+#[cfg(feature = "test_bvec")]
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::boxed::Box;
+    use std::mem::MaybeUninit;
+    use std::sync::atomic::{AtomicUsize, Ordering};
+
+    static A_COUNTER: AtomicUsize = AtomicUsize::new(0);
+
+    #[derive(Clone, Copy)]
+    struct TestAlloc;
+    impl BlockAllocator for TestAlloc {
+        fn alloc(&self) -> *mut u8 {
+            let b = Box::leak(Box::<[u8; block::SIZE]>::new_uninit());
+            eprintln!("alloc {:p}", b);
+            b.as_mut_ptr() as *mut _
+        }
+
+        unsafe fn free(&self, ptr: *mut u8) {
+            eprintln!("drop {:p}", ptr);
+            drop(Box::from_raw(ptr as *mut [u8; block::SIZE]));
+        }
+    }
+
+    #[test]
+    fn bvec_allocation() {
+        #[derive(Clone, Copy)]
+        struct A;
+        impl BlockAllocator for A {
+            fn alloc(&self) -> *mut u8 {
+                let b = Box::leak(Box::<[u8; block::SIZE]>::new_uninit());
+                A_COUNTER.fetch_add(1, Ordering::SeqCst);
+                b.as_mut_ptr() as *mut _
+            }
+
+            unsafe fn free(&self, ptr: *mut u8) {
+                A_COUNTER.fetch_sub(1, Ordering::SeqCst);
+                drop(Box::from_raw(ptr as *mut [u8; block::SIZE]));
+            }
+        }
+
+        let mut bvec = Bvec::new(A {});
+        assert_eq!(A_COUNTER.load(Ordering::Acquire), 0);
+
+        bvec.resize(123).unwrap();
+        unsafe {
+            for i in 0..L0_BLOCKS {
+                assert!(!bvec.l0[i].assume_init_ref().is_null());
+            }
+            let l1r = bvec.l1[0].assume_init_ref();
+            assert!(!l1r.is_null());
+            for i in 0..123 - L0_BLOCKS {
+                assert!(!l1r.as_ref_array()[i].assume_init_ref().is_null());
+            }
+        }
+        assert_eq!(A_COUNTER.load(Ordering::Acquire), 123 + 1);
+
+        bvec.resize(123 + block::ENTRY_COUNT).unwrap();
+        unsafe {
+            for i in 0..L0_BLOCKS {
+                assert!(!bvec.l0[i].assume_init_ref().is_null());
+            }
+            for i in 0..(123 + block::ENTRY_COUNT) - L0_BLOCKS {
+                let l1i = i / block::ENTRY_COUNT;
+                let l0i = i % block::ENTRY_COUNT;
+                let l1r = bvec.l1[l1i].assume_init_ref();
+                assert!(!l1r.is_null());
+                assert!(!l1r.as_ref_array()[l0i].assume_init_ref().is_null());
+            }
+        }
+        assert_eq!(
+            A_COUNTER.load(Ordering::Acquire),
+            123 + block::ENTRY_COUNT + 2
+        );
+
+        bvec.resize(L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT)
+            .unwrap();
+        unsafe {
+            for i in 0..L0_BLOCKS {
+                assert!(!bvec.l0[i].assume_init_ref().is_null());
+            }
+            for i in 0..L1_BLOCKS * block::ENTRY_COUNT {
+                let l1i = i / block::ENTRY_COUNT;
+                let l0i = i % block::ENTRY_COUNT;
+                let l1r = bvec.l1[l1i].assume_init_ref();
+                assert!(!l1r.is_null());
+                assert!(!l1r.as_ref_array()[l0i].assume_init_ref().is_null());
+            }
+        }
+        assert_eq!(
+            A_COUNTER.load(Ordering::Acquire),
+            L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT + L1_BLOCKS
+        );
+
+        bvec.resize(L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT + block::ENTRY_COUNT * 4)
+            .unwrap();
+        unsafe {
+            for i in 0..L0_BLOCKS {
+                assert!(!bvec.l0[i].assume_init_ref().is_null());
+            }
+            for i in 0..L1_BLOCKS * block::ENTRY_COUNT {
+                let l1i = i / block::ENTRY_COUNT;
+                let l0i = i % block::ENTRY_COUNT;
+                let l1r = bvec.l1[l1i].assume_init_ref();
+                assert!(!l1r.is_null());
+                assert!(!l1r.as_ref_array()[l0i].assume_init_ref().is_null());
+            }
+            let l2r = bvec.l2.assume_init_ref();
+            assert!(!l2r.is_null());
+            for i in 0..block::ENTRY_COUNT * 4 {
+                let l1i = i / block::ENTRY_COUNT;
+                let l0i = i % block::ENTRY_COUNT;
+                let l1r = l2r.as_ref_array()[l1i].assume_init_ref();
+                assert!(!l1r.is_null());
+                assert!(!l1r.as_ref_array()[l0i].assume_init_ref().is_null());
+            }
+        }
+        assert_eq!(
+            A_COUNTER.load(Ordering::Acquire),
+            L0_BLOCKS + // L0
+            L1_BLOCKS * block::ENTRY_COUNT + L1_BLOCKS + // L1
+            block::ENTRY_COUNT * 4 + 4 + 1
+        );
+
+        bvec.resize(L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT + block::ENTRY_COUNT * 3 + 1)
+            .unwrap();
+        unsafe {
+            for i in 0..L0_BLOCKS {
+                assert!(!bvec.l0[i].assume_init_ref().is_null());
+            }
+            for i in 0..L1_BLOCKS * block::ENTRY_COUNT {
+                let l1i = i / block::ENTRY_COUNT;
+                let l0i = i % block::ENTRY_COUNT;
+                let l1r = bvec.l1[l1i].assume_init_ref();
+                assert!(!l1r.is_null());
+                assert!(!l1r.as_ref_array()[l0i].assume_init_ref().is_null());
+            }
+            let l2r = bvec.l2.assume_init_ref();
+            assert!(!l2r.is_null());
+            for i in 0..block::ENTRY_COUNT * 3 + 1 {
+                let l1i = i / block::ENTRY_COUNT;
+                let l0i = i % block::ENTRY_COUNT;
+                let l1r = l2r.as_ref_array()[l1i].assume_init_ref();
+                assert!(!l1r.is_null());
+                assert!(!l1r.as_ref_array()[l0i].assume_init_ref().is_null());
+            }
+        }
+        assert_eq!(
+            A_COUNTER.load(Ordering::Acquire),
+            L0_BLOCKS + // L0
+            L1_BLOCKS * block::ENTRY_COUNT + L1_BLOCKS + // L1
+            block::ENTRY_COUNT * 3 + 1 + 4 + 1
+        );
+
+        bvec.resize(L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT + block::ENTRY_COUNT * 2 + 1)
+            .unwrap();
+        unsafe {
+            for i in 0..L0_BLOCKS {
+                assert!(!bvec.l0[i].assume_init_ref().is_null());
+            }
+            for i in 0..L1_BLOCKS * block::ENTRY_COUNT {
+                let l1i = i / block::ENTRY_COUNT;
+                let l0i = i % block::ENTRY_COUNT;
+                let l1r = bvec.l1[l1i].assume_init_ref();
+                assert!(!l1r.is_null());
+                assert!(!l1r.as_ref_array()[l0i].assume_init_ref().is_null());
+            }
+            let l2r = bvec.l2.assume_init_ref();
+            assert!(!l2r.is_null());
+            for i in 0..block::ENTRY_COUNT * 2 + 1 {
+                let l1i = i / block::ENTRY_COUNT;
+                let l0i = i % block::ENTRY_COUNT;
+                let l1r = l2r.as_ref_array()[l1i].assume_init_ref();
+                assert!(!l1r.is_null());
+                assert!(!l1r.as_ref_array()[l0i].assume_init_ref().is_null());
+            }
+        }
+        assert_eq!(
+            A_COUNTER.load(Ordering::Acquire),
+            L0_BLOCKS + // L0
+            L1_BLOCKS * block::ENTRY_COUNT + L1_BLOCKS + // L1
+            block::ENTRY_COUNT * 2 + 1 + 3 + 1
+        );
+
+        bvec.resize(L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT + 1)
+            .unwrap();
+        unsafe {
+            for i in 0..L0_BLOCKS {
+                assert!(!bvec.l0[i].assume_init_ref().is_null());
+            }
+            for i in 0..L1_BLOCKS * block::ENTRY_COUNT {
+                let l1i = i / block::ENTRY_COUNT;
+                let l0i = i % block::ENTRY_COUNT;
+                let l1r = bvec.l1[l1i].assume_init_ref();
+                assert!(!l1r.is_null());
+                assert!(!l1r.as_ref_array()[l0i].assume_init_ref().is_null());
+            }
+            let l2r = bvec.l2.assume_init_ref();
+            assert!(!l2r.is_null());
+            let l1r = l2r.as_ref_array()[0].assume_init_ref();
+            assert!(!l1r.is_null());
+            assert!(!l1r.as_ref_array()[0].assume_init_ref().is_null());
+        }
+        assert_eq!(
+            A_COUNTER.load(Ordering::Acquire),
+            L0_BLOCKS + // L0
+            L1_BLOCKS * block::ENTRY_COUNT + L1_BLOCKS + // L1
+            1 + 1 + 1
+        );
+
+        bvec.resize(L0_BLOCKS + 3 * block::ENTRY_COUNT + 1).unwrap();
+        unsafe {
+            for i in 0..L0_BLOCKS {
+                assert!(!bvec.l0[i].assume_init_ref().is_null());
+            }
+            for i in 0..3 * block::ENTRY_COUNT + 1 {
+                let l1i = i / block::ENTRY_COUNT;
+                let l0i = i % block::ENTRY_COUNT;
+                let l1r = bvec.l1[l1i].assume_init_ref();
+                assert!(!l1r.is_null());
+                assert!(!l1r.as_ref_array()[l0i].assume_init_ref().is_null());
+            }
+            let l2r = bvec.l2.assume_init_ref();
+            assert!(l2r.is_null());
+        }
+        assert_eq!(
+            A_COUNTER.load(Ordering::Acquire),
+            L0_BLOCKS + // L0
+            3 * block::ENTRY_COUNT + 1 + 4
+        );
+
+        bvec.resize(L0_BLOCKS).unwrap();
+        unsafe {
+            for i in 0..L0_BLOCKS {
+                assert!(!bvec.l0[i].assume_init_ref().is_null());
+            }
+            assert!(bvec.l1[0].assume_init_ref().is_null());
+        }
+        assert_eq!(A_COUNTER.load(Ordering::Acquire), L0_BLOCKS);
+
+        bvec.resize(12).unwrap();
+        unsafe {
+            for i in 0..12 {
+                assert!(!bvec.l0[i].assume_init_ref().is_null());
+            }
+        }
+        assert_eq!(A_COUNTER.load(Ordering::Acquire), 12);
+
+        bvec.resize(0).unwrap();
+        unsafe {
+            for i in 0..L0_BLOCKS {
+                assert!(bvec.l0[i].assume_init_ref().is_null());
+            }
+        }
+        assert_eq!(A_COUNTER.load(Ordering::Acquire), 0);
+    }
+
+    #[test]
+    fn bvec_index_l0() {
+        let mut bvec = Bvec::new(TestAlloc {});
+        bvec.resize(L0_BLOCKS).unwrap();
+
+        for i in 0..L0_BLOCKS {
+            let block = &bvec[i];
+            assert_eq!(block as *const _, bvec.l0[i].as_ptr());
+        }
+    }
+
+    #[test]
+    fn bvec_index_l1() {
+        let mut bvec = Bvec::new(TestAlloc {});
+        bvec.resize(L0_BLOCKS + block::ENTRY_COUNT * 2 + 3).unwrap();
+
+        for i in 0..block::ENTRY_COUNT * 2 + 3 {
+            let l1i = i / block::ENTRY_COUNT;
+            let l0i = i % block::ENTRY_COUNT;
+            let block = &bvec[i + L0_BLOCKS];
+            let l1r = unsafe { bvec.l1[l1i].assume_init_ref() };
+            assert_eq!(block as *const _, l1r.as_ref_array()[l0i].as_ptr());
+        }
+    }
+
+    #[test]
+    fn bvec_index_l2() {
+        let mut bvec = Bvec::new(TestAlloc {});
+        bvec.resize(L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT + 3)
+            .unwrap();
+
+        for i in 0..3 {
+            let l1i = i / block::ENTRY_COUNT;
+            let l0i = i % block::ENTRY_COUNT;
+            let block = &bvec[i + L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT];
+            let l2r = unsafe { bvec.l2.assume_init_ref() };
+            let l1r = unsafe { l2r.as_ref_array()[l1i].assume_init_ref() };
+            assert_eq!(block as *const _, l1r.as_ref_array()[l0i].as_ptr());
+        }
+    }
+
+    #[test]
+    #[should_panic]
+    fn bvec_index_invalid_l0_0() {
+        let bvec = Bvec::new(TestAlloc {});
+        let _block = &bvec[0];
+    }
+
+    #[test]
+    #[should_panic]
+    fn bvec_index_invalid_l0_1() {
+        let mut bvec = Bvec::new(TestAlloc {});
+        bvec.resize(13).unwrap();
+        let _block = &bvec[15];
+    }
+
+    #[test]
+    #[should_panic]
+    fn bvec_index_invalid_l1_0() {
+        let mut bvec = Bvec::new(TestAlloc {});
+        bvec.resize(13).unwrap();
+        let _block = &bvec[L0_BLOCKS + 2];
+    }
+
+    #[test]
+    #[should_panic]
+    fn bvec_index_invalid_l1_1() {
+        let mut bvec = Bvec::new(TestAlloc {});
+        bvec.resize(L0_BLOCKS + block::ENTRY_COUNT * 2 + 3).unwrap();
+        let _block = &bvec[L0_BLOCKS + block::ENTRY_COUNT * 2 + 6];
+    }
+
+    #[test]
+    #[should_panic]
+    fn bvec_index_invalid_l1_2() {
+        let mut bvec = Bvec::new(TestAlloc {});
+        bvec.resize(L0_BLOCKS + block::ENTRY_COUNT * 2 + 3).unwrap();
+        let _block = &bvec[L0_BLOCKS + block::ENTRY_COUNT * 3 + 1];
+    }
+
+    #[test]
+    #[should_panic]
+    fn bvec_index_invalid_l2_0() {
+        let mut bvec = Bvec::new(TestAlloc {});
+        bvec.resize(13).unwrap();
+        let _block = &bvec[L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT + 3];
+    }
+
+    #[test]
+    #[should_panic]
+    fn bvec_index_invalid_l2_1() {
+        let mut bvec = Bvec::new(TestAlloc {});
+        bvec.resize(L0_BLOCKS + block::ENTRY_COUNT * 3 + 13)
+            .unwrap();
+        let _block = &bvec[L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT + 3];
+    }
+
+    #[test]
+    #[should_panic]
+    fn bvec_index_invalid_l2_2() {
+        let mut bvec = Bvec::new(TestAlloc {});
+        bvec.resize(L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT + 6)
+            .unwrap();
+        let _block = &bvec[L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT + 8];
+    }
+
+    #[test]
+    #[should_panic]
+    fn bvec_index_invalid_l2_3() {
+        let mut bvec = Bvec::new(TestAlloc {});
+        bvec.resize(L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT + block::ENTRY_COUNT * 2 + 7)
+            .unwrap();
+        let _block =
+            &bvec[L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT + block::ENTRY_COUNT * 2 + 13];
+    }
+
+    #[test]
+    #[should_panic]
+    fn bvec_index_invalid_l2_4() {
+        let mut bvec = Bvec::new(TestAlloc {});
+        bvec.resize(L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT + block::ENTRY_COUNT * 2 + 13)
+            .unwrap();
+        let _block = &bvec[L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT + block::ENTRY_COUNT * 3 + 2];
+    }
+
+    #[test]
+    fn bvec_write_read() {
+        let mut bvec = Bvec::new(TestAlloc {});
+        const N: usize = block::SIZE * (L0_BLOCKS + L1_BLOCKS * block::ENTRY_COUNT + 3);
+        let mut data = vec![0u8; N];
+        for i in 0..N {
+            data[i] = (i & 0xFF) as u8;
+        }
+        assert_eq!(bvec.write(0, &data[..]), Ok(N));
+
+        let mut buf = vec![0u8; 327];
+        let mut off = 0usize;
+        let mut rem = N;
+        while rem != 0 {
+            let count = min(rem, buf.len());
+            assert_eq!(bvec.read(off, &mut buf[..]), Ok(count));
+
+            for i in 0..count {
+                assert_eq!(buf[i], ((i + off) & 0xFF) as u8);
+            }
+
+            rem -= count;
+            off += count;
+        }
+    }
+}

fs/ramfs/src/lib.rs

@@ -0,0 +1,53 @@
+#![no_std]
+#![feature(new_uninit, maybe_uninit_uninit_array, maybe_uninit_extra)]
+
+extern crate alloc;
+#[cfg(test)]
+#[macro_use]
+extern crate std;
+
+use alloc::rc::Rc;
+use core::cell::RefCell;
+use error::Errno;
+use spin::Mutex;
+use vfs::{Node, NodeRef, NodeType};
+
+mod block;
+pub use block::{BlockAllocator, BlockRef};
+mod bvec;
+use bvec::Bvec;
+
+pub struct Ramfs<'a> {
+    root: NodeRef,
+    allocator: &'a Mutex<dyn BlockAllocator>,
+}
+
+pub struct NodeData {
+}
+
+fn load_tar(base: *const u8, size: usize) -> Result<NodeRef, Errno> {
+    let root = Node::directory(b"");
+    // TODO
+    Ok(root)
+}
+
+pub fn open(
+    base: *const u8,
+    size: usize,
+    allocator: &Mutex<dyn BlockAllocator>,
+) -> Result<Ramfs, Errno> {
+    let root = load_tar(base, size)?;
+
+    Ok(Ramfs { root, allocator })
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn ramfs_open() {
+        let data = include_str!("../test/test0.tar");
+        //let fs = open(data.as_ptr(), data.bytes().len()).unwrap();
+    }
+}

fs/ramfs/test/file0.txt

@@ -0,0 +1,2 @@
+This is a file
+File0

fs/vfs/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "vfs"
+version = "0.1.0"
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+error = { path = "../../error" }
+spin = "*"

fs/vfs/src/ioctx.rs

@@ -0,0 +1,187 @@
+use crate::{path_element, Node, NodeRef};
+use alloc::rc::Rc;
+use error::Errno;
+
+pub struct Ioctx {
+    pub root: NodeRef,
+    pub cwd: NodeRef,
+}
+
+impl Ioctx {
+    fn lookup_or_load(parent: NodeRef, name: &[u8]) -> Result<NodeRef, Errno> {
+        let p = parent.borrow_mut();
+
+        if !p.is_directory() {
+            return Err(Errno::NotADirectory);
+        }
+
+        if let Some(node) = p.children().find(|&node| node.borrow().name() == name) {
+            return Ok(node.clone());
+        }
+
+        if let Some(ops) = p.ops.as_ref() {
+            todo!();
+        }
+
+        Err(Errno::DoesNotExist)
+    }
+
+    fn _find(&self, mut at: NodeRef, path: &[u8]) -> Result<NodeRef, Errno> {
+        let mut child_path: &[u8];
+        let mut element_name: &[u8];
+
+        if path.is_empty() {
+            return Ok(at);
+        }
+
+        child_path = path;
+        loop {
+            let r = path_element(child_path);
+            element_name = r.0;
+            child_path = r.1;
+
+            match element_name {
+                b"." => {
+                    if child_path.is_empty() {
+                        return Ok(at);
+                    }
+                }
+                b".." => {
+                    let parent = at.borrow().parent().unwrap_or(at.clone());
+                    at = parent;
+                    if child_path.is_empty() {
+                        return Ok(at);
+                    }
+                }
+                _ => break,
+            }
+        }
+
+        if element_name.is_empty() && child_path.is_empty() {
+            return Ok(at);
+        }
+        assert!(!element_name.is_empty());
+        let child = Self::lookup_or_load(at, element_name)?;
+
+        if child_path.is_empty() {
+            Ok(child)
+        } else {
+            self._find(child, child_path)
+        }
+    }
+
+    pub fn find(&self, at: Option<NodeRef>, mut path: &[u8]) -> Result<NodeRef, Errno> {
+        if path.is_empty() {
+            return at.ok_or(Errno::DoesNotExist);
+        }
+
+        let at = if path[0] == b'/' {
+            let index = path
+                .iter()
+                .position(|&x| x != b'/')
+                .unwrap_or(path.len() - 1);
+            path = &path[index..];
+            self.root.clone()
+        } else if let Some(node) = at {
+            node
+        } else {
+            self.cwd.clone()
+        };
+
+        self._find(at, path)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::Node;
+
+    #[test]
+    fn ioctx_find_at() {
+        let r = Node::directory(b"");
+        let d0 = Node::directory(b"dir0");
+        let d1 = Node::directory(b"dir1");
+        let d0d0 = Node::directory(b"dir0");
+        let d0f0 = Node::file(b"file0");
+
+        Node::attach(r.clone(), d0.clone());
+        Node::attach(r.clone(), d1.clone());
+        Node::attach(d0.clone(), d0d0.clone());
+        Node::attach(d0.clone(), d0f0.clone());
+
+        let ioctx = Ioctx {
+            root: r.clone(),
+            cwd: r.clone(),
+        };
+
+        assert!(Rc::ptr_eq(
+            ioctx.find(Some(r.clone()), b"dir0").as_ref().unwrap(),
+            &d0
+        ));
+        assert!(Rc::ptr_eq(
+            ioctx.find(Some(d0.clone()), b"dir0").as_ref().unwrap(),
+            &d0d0
+        ));
+        assert!(Rc::ptr_eq(
+            ioctx.find(Some(r.clone()), b"dir0/dir0").as_ref().unwrap(),
+            &d0d0
+        ));
+        assert!(Rc::ptr_eq(
+            ioctx.find(Some(d0.clone()), b"file0").as_ref().unwrap(),
+            &d0f0
+        ));
+        assert!(Rc::ptr_eq(
+            ioctx.find(Some(r.clone()), b"dir0/file0").as_ref().unwrap(),
+            &d0f0
+        ));
+        assert!(Rc::ptr_eq(
+            ioctx.find(Some(d0.clone()), b"../dir1").as_ref().unwrap(),
+            &d1
+        ));
+        assert!(Rc::ptr_eq(
+            ioctx.find(Some(d0.clone()), b"./dir0").as_ref().unwrap(),
+            &d0d0
+        ));
+        assert!(Rc::ptr_eq(
+            ioctx.find(Some(d0.clone()), b"././dir0/.").as_ref().unwrap(),
+            &d0d0
+        ));
+        assert!(Rc::ptr_eq(
+            ioctx.find(Some(d0.clone()), b"././dir0/./").as_ref().unwrap(),
+            &d0d0
+        ));
+        assert!(Rc::ptr_eq(
+            ioctx.find(Some(d0.clone()), b"././dir0/").as_ref().unwrap(),
+            &d0d0
+        ));
+        assert!(Rc::ptr_eq(
+            ioctx.find(Some(d0.clone()), b"././dir0/..").as_ref().unwrap(),
+            &d0
+        ));
+        assert!(Rc::ptr_eq(
+            ioctx.find(Some(d0.clone()), b"././dir0/../..").as_ref().unwrap(),
+            &r
+        ));
+        assert!(Rc::ptr_eq(
+            ioctx.find(Some(d0.clone()), b"././dir0/../../../").as_ref().unwrap(),
+            &r
+        ));
+
+        // TODO make these illegal
+        assert!(Rc::ptr_eq(
+            ioctx.find(Some(d0.clone()), b"././file0/..").as_ref().unwrap(),
+            &d0
+        ));
+        assert!(Rc::ptr_eq(
+            ioctx.find(Some(d0.clone()), b"././file0/").as_ref().unwrap(),
+            &d0f0
+        ));
+        assert!(Rc::ptr_eq(
+            ioctx.find(Some(d0.clone()), b"././file0/.").as_ref().unwrap(),
+            &d0f0
+        ));
+
+        ioctx.find(Some(r.clone()), b"dir0/dir1").expect_err("");
+    }
+}

fs/vfs/src/lib.rs

@@ -0,0 +1,28 @@
+#![no_std]
+
+#[allow(unused_imports)]
+#[macro_use]
+extern crate alloc;
+#[cfg(test)]
+#[macro_use]
+extern crate std;
+
+use error::Errno;
+
+pub mod node;
+mod util;
+pub use node::{Node, NodeOperations, NodeRef, NodeType};
+mod ioctx;
+pub use ioctx::Ioctx;
+
+pub fn path_element(path: &[u8]) -> (&[u8], &[u8]) {
+    if let Some(mut index) = path.iter().position(|&x| x == b'/') {
+        let elem = &path[..index];
+        while index < path.len() && path[index] == b'/' {
+            index += 1;
+        }
+        (elem, &path[index..])
+    } else {
+        (path, b"")
+    }
+}

fs/vfs/src/node.rs

@@ -0,0 +1,181 @@
+use crate::util::{iter::LockedIterator, FixedStr};
+use alloc::{boxed::Box, rc::Rc, vec::Vec};
+use core::any::Any;
+use core::cell::RefCell;
+use core::ffi::c_void;
+use core::fmt;
+use core::ptr::null_mut;
+use error::Errno;
+use spin::Mutex;
+
+pub type NodeRef = Rc<RefCell<Node>>;
+
+pub enum NodeType {
+    Regular,
+    Directory { children: Vec<NodeRef> },
+}
+
+pub const NODE_MEMORY: u32 = 1 << 0;
+
+pub struct NodeOperations {
+    lookup: Option<fn(parent: NodeRef, name: &[u8]) -> Result<NodeRef, Errno>>,
+    drop: Option<fn(node: &mut Node)>,
+}
+
+pub struct Node {
+    name: FixedStr<64>,
+    typ: NodeType,
+    flags: u32,
+
+    pub(crate) ops: Option<&'static NodeOperations>,
+    pub data: *mut c_void,
+
+    target: Option<NodeRef>,
+    parent: Option<NodeRef>,
+}
+
+impl Node {
+    pub fn new(name: &[u8], typ: NodeType) -> Self {
+        let mut r = Self {
+            name: FixedStr::empty(),
+            typ,
+            flags: 0,
+
+            ops: None,
+            data: null_mut(),
+
+            parent: None,
+            target: None,
+        };
+        r.name.copy_from_slice(name);
+        r
+    }
+
+    pub fn directory(name: &[u8]) -> Rc<RefCell<Self>> {
+        Rc::new(RefCell::new(Self::new(
+            name,
+            NodeType::Directory { children: vec![] },
+        )))
+    }
+
+    pub fn file(name: &[u8]) -> Rc<RefCell<Self>> {
+        Rc::new(RefCell::new(Self::new(name, NodeType::Regular)))
+    }
+
+    pub fn name(&self) -> &FixedStr<64> {
+        &self.name
+    }
+
+    pub fn parent(&self) -> Option<NodeRef> {
+        self.parent.clone()
+    }
+
+    pub fn is_directory(&self) -> bool {
+        matches!(&self.typ, NodeType::Directory { .. })
+    }
+
+    pub fn children(&self) -> impl Iterator<Item = &NodeRef> {
+        let lock = TREE_MUTEX.lock();
+        match &self.typ {
+            NodeType::Directory { children } => LockedIterator::new(children.iter(), lock),
+            _ => panic!("Not a directory"),
+        }
+    }
+
+    pub fn children_mut(&mut self) -> impl Iterator<Item = &mut NodeRef> {
+        let lock = TREE_MUTEX.lock();
+        match &mut self.typ {
+            NodeType::Directory { children } => LockedIterator::new(children.iter_mut(), lock),
+            _ => panic!("Not a directory"),
+        }
+    }
+
+    pub fn attach(parent: NodeRef, child: NodeRef) {
+        let _lock = TREE_MUTEX.lock();
+        assert!(child.borrow().parent.is_none());
+        match &mut parent.borrow_mut().typ {
+            NodeType::Directory { children } => children.push(child.clone()),
+            _ => panic!("Not a directory"),
+        }
+        child.borrow_mut().parent.replace(parent.clone());
+    }
+
+    pub fn detach(child: NodeRef) {
+        let _lock = TREE_MUTEX.lock();
+        assert!(child.borrow().parent.is_some());
+        let parent = child.borrow_mut().parent.take().unwrap();
+        match &mut parent.borrow_mut().typ {
+            NodeType::Directory { children } => {
+                children.remove(children.iter().position(|x| Rc::ptr_eq(x, &child)).unwrap());
+            }
+            _ => panic!("Not a directory"),
+        };
+    }
+}
+
+impl Drop for Node {
+    fn drop(&mut self) {
+        if let Some(ops) = self.ops.as_ref() {
+            if let Some(do_drop) = ops.drop.as_ref() {
+                do_drop(self);
+            }
+        }
+    }
+}
+
+impl fmt::Debug for Node {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "Node {{ name={:?}, typ=??? }}", self.name)
+    }
+}
+
+static TREE_MUTEX: Mutex<()> = Mutex::new(());
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use core::any::{type_name, TypeId};
+    use core::sync::atomic::{AtomicBool, Ordering};
+
+    #[test]
+    fn node_new() {
+        let r = Node::directory(b"");
+        let n = r.borrow();
+        assert_eq!(n.name, b""[..]);
+        assert!(matches!(n.typ, NodeType::Directory { .. }));
+        assert!(n.ops.is_none());
+        assert!(n.target.is_none());
+        assert!(n.parent.is_none());
+
+        let r = Node::file(b"file1");
+        let n = r.borrow();
+        assert_eq!(n.name, b"file1"[..]);
+        assert!(matches!(n.typ, NodeType::Regular));
+        assert!(n.ops.is_none());
+        assert!(n.target.is_none());
+        assert!(n.parent.is_none());
+    }
+
+    #[test]
+    fn node_attach() {
+        let r0 = Node::directory(b"");
+        let r1 = Node::directory(b"1234");
+
+        // Attach
+        Node::attach(r0.clone(), r1.clone());
+
+        assert!(Rc::ptr_eq(r1.borrow().parent.as_ref().unwrap(), &r0));
+        {
+            let n0 = r0.borrow();
+            let mut it = n0.children();
+            assert!(Rc::ptr_eq(&it.next().unwrap(), &r1));
+            assert!(it.next().is_none());
+        }
+
+        // Detach
+        Node::detach(r1.clone());
+
+        assert!(r1.borrow().parent.is_none());
+        assert_eq!(r0.borrow().children().count(), 0);
+    }
+}

fs/vfs/src/util/iter.rs

@@ -0,0 +1,22 @@
+use spin::MutexGuard;
+
+pub struct LockedIterator<'a, T: ?Sized, I: Iterator<Item = T>> {
+    inner: I,
+    #[allow(dead_code)]
+    lock: MutexGuard<'a, ()>,
+}
+
+impl<'a, T, I: Iterator<Item = T>> Iterator for LockedIterator<'a, T, I> {
+    type Item = T;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.inner.next()
+    }
+}
+
+impl<'a, T, I: Iterator<Item = T>> LockedIterator<'a, T, I> {
+    #[inline]
+    pub fn new(inner: I, lock: MutexGuard<'a, ()>) -> Self {
+        Self { inner, lock }
+    }
+}

fs/vfs/src/util/mod.rs

@@ -0,0 +1,94 @@
+use alloc::boxed::Box;
+use core::alloc::Layout;
+use core::ffi::c_void;
+use core::fmt;
+
+pub mod iter;
+
+#[repr(transparent)]
+pub struct FixedStr<const N: usize> {
+    inner: [u8; N],
+}
+
+impl<const N: usize> FixedStr<N> {
+    pub fn new(s: &[u8]) -> Self {
+        let mut r = Self::empty();
+        r.copy_from_slice(s);
+        r
+    }
+
+    pub const fn empty() -> Self {
+        Self { inner: [0; N] }
+    }
+
+    pub fn len(&self) -> usize {
+        self.inner.iter().position(|&n| n == 0).unwrap_or(N)
+    }
+
+    pub fn copy_from_slice(&mut self, src: &[u8]) {
+        let src_len = src.len();
+        if src_len == 0 {
+            self.inner[0] = 0;
+            return;
+        }
+        if src_len >= N {
+            panic!("String buffer overflow");
+        }
+        let dst = &mut self.inner[..src_len];
+        dst.copy_from_slice(src);
+        self.inner[src_len] = 0;
+    }
+}
+
+impl<const N: usize> PartialEq<[u8]> for FixedStr<N> {
+    fn eq(&self, other: &[u8]) -> bool {
+        let self_len = self.len();
+        if self_len != other.len() {
+            return false;
+        }
+        &self.inner[..self_len] == other
+    }
+}
+
+impl<const N: usize> fmt::Display for FixedStr<N> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        for byte in self.inner {
+            if byte == 0 {
+                break;
+            }
+            write!(f, "{}", byte as char)?;
+        }
+        Ok(())
+    }
+}
+
+impl<const N: usize> fmt::Debug for FixedStr<N> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::Display::fmt(self, f)?;
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn fixed_str_display() {
+        let s = FixedStr::<64>::new(b"test");
+        assert_eq!(format!("{}", s), "test");
+    }
+
+    #[test]
+    fn fixed_str_length() {
+        assert_eq!(FixedStr::<64>::empty().len(), 0);
+        assert_eq!(FixedStr::<64>::new(b"test1").len(), 5);
+        assert_eq!(FixedStr::<6>::new(b"test1").len(), 5);
+    }
+
+    #[test]
+    fn fixed_str_eq_slice() {
+        assert_eq!(FixedStr::<64>::empty(), b""[..]);
+        assert_eq!(FixedStr::<64>::new(b"1234"), b"1234"[..]);
+    }
+}

kernel/src/arch/cpu.rs

@@ -1,4 +1,4 @@
-use crate::arch::{intrin, smp};
+use crate::arch::intrin;
 use core::mem::MaybeUninit;
 use core::ops::{Deref, DerefMut};
 use core::sync::atomic::AtomicUsize;
@@ -8,19 +8,20 @@ pub struct Cpu {
     index: u32, // 0x00
 }
 
-#[repr(transparent)]
 pub struct CpuRef {
     inner: &'static mut Cpu,
 }
 
 impl Cpu {
     fn new(index: u32) -> Self {
-        Self { index }
+        Self {
+            index,
+        }
     }
 
     #[inline(always)]
     pub unsafe fn get_raw() -> &'static mut Cpu {
-        &mut *(intrin::read_tpidr_el1() as *mut _)
+        CPU.assume_init_mut()
     }
 
     #[inline(always)]
@@ -30,16 +31,13 @@ impl Cpu {
 
     #[inline]
     pub fn get() -> CpuRef {
-        // TODO lock
         CpuRef {
             inner: unsafe { Self::get_raw() },
         }
     }
-}
 
-impl Drop for CpuRef {
-    fn drop(&mut self) {
-        // TODO release
+    pub unsafe fn init(index: u32) {
+        CPU.write(Self::new(index));
     }
 }
 
@@ -57,14 +55,7 @@ impl DerefMut for CpuRef {
     }
 }
 
-pub static mut CPUS: [MaybeUninit<Cpu>; smp::MAX_CPU] = MaybeUninit::uninit_array();
-pub static CPU_COUNT: AtomicUsize = AtomicUsize::new(1);
-
-fn set_cpu(cpu: *mut Cpu) {
-    unsafe {
-        intrin::write_tpidr_el1(cpu as usize);
-    }
-}
+static mut CPU: MaybeUninit<Cpu> = MaybeUninit::uninit();
 
 #[inline(always)]
 pub fn get_phys_id() -> usize {
@@ -73,7 +64,6 @@ pub fn get_phys_id() -> usize {
 
 pub fn init(index: usize) {
     unsafe {
-        CPUS[index].write(Cpu::new(index as u32));
-        set_cpu(CPUS[index].as_mut_ptr());
+        Cpu::init(index as u32);
     }
 }

kernel/src/arch/exception.rs

@@ -28,9 +28,20 @@ struct ExceptionContext {
     far: usize,
 }
 
+impl ExceptionContext {
+    pub fn dump(&self) {
+        debugln!(" x0 = {:#018x},  x1 = {:#018x}", self.x0, self.x1);
+        debugln!(" x2 = {:#018x},  x3 = {:#018x}", self.x2, self.x3);
+        debugln!(" x4 = {:#018x},  x5 = {:#018x}", self.x4, self.x5);
+        debugln!(" x6 = {:#018x},  x7 = {:#018x}", self.x6, self.x7);
+        debugln!(" x8 = {:#018x},  x9 = {:#018x}", self.x8, self.x9);
+    }
+}
+
 #[no_mangle]
-extern "C" fn exc_handler(_context: ExceptionContext) -> ! {
-    debug!("Unhandled exception\n");
+extern "C" fn exc_handler(ctx: ExceptionContext) -> ! {
+    debugln!("Unhandled exception");
+    debugln!("FAR = {:#018x}, ESR = {:#018x}", ctx.far, ctx.esr);
 
     loop {}
 }

kernel/src/arch/intrin.rs

@@ -1,3 +1,10 @@
+pub fn delay(mut p: usize) {
+    while p != 0 {
+        nop();
+        p -= 1;
+    }
+}
+
 #[inline(always)]
 pub unsafe fn disable_irq() {
     llvm_asm!("msr daifset, #0xF");
@@ -8,6 +15,21 @@ pub unsafe fn enable_irq() {
     llvm_asm!("msr daifclr, #0xF");
 }
 
+#[inline(always)]
+pub unsafe fn save_irq() -> usize {
+    let mut out: usize;
+    llvm_asm!(r#"
+        mrs $0, daif
+        msr daifset, #0xF
+    "#:"=r"(out));
+    out
+}
+
+#[inline(always)]
+pub unsafe fn restore_irq(state: usize) {
+    llvm_asm!("msr daif, $0"::"r"(state));
+}
+
 #[inline(always)]
 pub fn nop() {
     unsafe {

kernel/src/arch/mach_bcm283x/aux.rs

@@ -12,7 +12,7 @@ impl Aux {
     const AUX_ENABLES_MUART: u32 = 1 << 0;
 
     pub unsafe fn enable_uart(&self) {
-        let tmp = mmio_read(Self::REG_AUX_ENABLES);
+        let tmp: u32 = mmio_read(Self::REG_AUX_ENABLES);
         mmio_write(Self::REG_AUX_ENABLES, tmp | Self::AUX_ENABLES_MUART);
     }
 }
@@ -61,8 +61,7 @@ impl SerialDevice for AuxUart {
 
 impl InterruptHandler for AuxUart {
     fn do_irq(&self, _irq: u32) {
-        let byte = unsafe { mmio_read(Self::REG_AUX_MU_IO) } as u8;
-        debugln!("{}", byte as char);
+        let _byte = unsafe { mmio_read::<u32>(Self::REG_AUX_MU_IO) } as u8;
     }
 }
 

kernel/src/arch/mach_bcm283x/intc.rs

@@ -59,7 +59,7 @@ impl InterruptController for Qa7Intc {
         match irq {
             super::IRQ_LOCAL_TIMER => {
                 let phys_core_id = cpu::get_phys_id();
-                let tmp = mmio_read(Self::REG_TIMER_INTC + 4 * phys_core_id);
+                let tmp: u32 = mmio_read(Self::REG_TIMER_INTC + 4 * phys_core_id);
                 mmio_write(
                     Self::REG_TIMER_INTC + 4 * phys_core_id,
                     tmp | Self::INTC_CNTPNSIRQ_IRQ,
@@ -74,7 +74,7 @@ impl InterruptController for Qa7Intc {
     }
 
     fn is_irq_pending(&self, irq: u32) -> bool {
-        unsafe { mmio_read(Self::REG_INT_SRC) & (1 << irq) != 0 }
+        unsafe { mmio_read::<u32>(Self::REG_INT_SRC) & (1 << irq) != 0 }
     }
 
     unsafe fn clear_irq(&self, _irq: u32) {}
@@ -95,9 +95,9 @@ impl InterruptController for Bcm2837Intc {
 
     fn is_irq_pending(&self, irq: u32) -> bool {
         if irq < 32 {
-            unsafe { mmio_read(Self::REG_PENDING_IRQ1) & (1 << irq) != 0 }
+            unsafe { mmio_read::<u32>(Self::REG_PENDING_IRQ1) & (1 << irq) != 0 }
         } else if irq < 64 {
-            unsafe { mmio_read(Self::REG_PENDING_IRQ2) & (1 << (irq - 32)) != 0 }
+            unsafe { mmio_read::<u32>(Self::REG_PENDING_IRQ2) & (1 << (irq - 32)) != 0 }
         } else {
             false
         }

kernel/src/arch/mach_bcm283x/mbox.rs

@@ -1,5 +1,5 @@
 use crate::{
-    arch::{cpu, intrin, mmio_read, mmio_write, smp::{self, IpiDelivery, IpiMessage}},
+    arch::{cpu, intrin, mmio_read, mmio_write},
     KernelSpace,
 };
 use address::{PhysicalAddress, VirtualAddress};
@@ -28,56 +28,59 @@ struct Message {
 }
 
 static mut MESSAGE: Message = Message { data: [0; 36] };
-pub static CORE_MBOX0: CoreMailbox = CoreMailbox { index: 0 };
-
-pub struct CoreMailbox {
-    index: usize,
-}
-
-impl IpiDelivery for CoreMailbox {
-    fn enable(&self) {
-        let phys_core_id = cpu::get_phys_id();
-        unsafe {
-            mmio_write(Self::REG_INTC + phys_core_id * 4, 1 << self.index);
-        }
-    }
-
-    fn send_ipi(target_id: u32, message: IpiMessage) {
-        unsafe {
-            mmio_write(Self::REG_SET + target_id as usize * 16, 1 << (message as u32));
-        }
-    }
-}
-
-impl CoreMailbox {
-    const REG_INTC: PhysicalAddress = PhysicalAddress::new(0x40000050);
-    const REG_SET: PhysicalAddress = PhysicalAddress::new(0x40000080);
-    const REG_RDCLR: PhysicalAddress = PhysicalAddress::new(0x400000C0);
-
-    pub fn do_irq(&self) {
-        let phys_core_id = cpu::get_phys_id();
-        let value = unsafe { mmio_read(Self::REG_RDCLR + phys_core_id * 16 + self.index * 4) };
-        if value != 0 {
-            macro_rules! test_ipi {
-                ($value:expr, $msg:expr) => {
-                    if $value & (1 << ($msg as u32)) != 0 {
-                        smp::handle_ipi($msg);
-                    }
-                }
-            }
-
-            test_ipi!(value, IpiMessage::Halt);
-            test_ipi!(value, IpiMessage::Tick);
-
-            unsafe {
-                mmio_write(
-                    Self::REG_RDCLR + phys_core_id * 16 + self.index * 4,
-                    0xFFFFFFFF,
-                );
-            }
-        }
-    }
-}
+//pub static CORE_MBOX0: CoreMailbox = CoreMailbox { index: 0 };
+//
+//pub struct CoreMailbox {
+//    index: usize,
+//}
+//
+//impl IpiDelivery for CoreMailbox {
+//    fn enable(&self) {
+//        let phys_core_id = cpu::get_phys_id();
+//        unsafe {
+//            mmio_write(Self::REG_INTC + phys_core_id * 4, 1 << self.index);
+//        }
+//    }
+//
+//    fn send_ipi(target_id: u32, message: IpiMessage) {
+//        unsafe {
+//            mmio_write(
+//                Self::REG_SET + target_id as usize * 16,
+//                1 << (message as u32),
+//            );
+//        }
+//    }
+//}
+//
+//impl CoreMailbox {
+//    const REG_INTC: PhysicalAddress = PhysicalAddress::new(0x40000050);
+//    const REG_SET: PhysicalAddress = PhysicalAddress::new(0x40000080);
+//    const REG_RDCLR: PhysicalAddress = PhysicalAddress::new(0x400000C0);
+//
+//    pub fn do_irq(&self) {
+//        let phys_core_id = cpu::get_phys_id();
+//        let value: u32 = unsafe { mmio_read(Self::REG_RDCLR + phys_core_id * 16 + self.index * 4) };
+//        if value != 0 {
+//            macro_rules! test_ipi {
+//                ($value:expr, $msg:expr) => {
+//                    if $value & (1 << ($msg as u32)) != 0 {
+//                        smp::handle_ipi($msg);
+//                    }
+//                };
+//            }
+//
+//            test_ipi!(value, IpiMessage::Halt);
+//            test_ipi!(value, IpiMessage::Tick);
+//
+//            unsafe {
+//                mmio_write::<u32>(
+//                    Self::REG_RDCLR + phys_core_id * 16 + self.index * 4,
+//                    0xFFFFFFFF,
+//                );
+//            }
+//        }
+//    }
+//}
 
 unsafe fn call(ch: u32) -> Result<(), ()> {
     let value = (usize::from(PhysicalAddress::from(
@@ -85,7 +88,7 @@ unsafe fn call(ch: u32) -> Result<(), ()> {
     )) as u32)
         | (ch & 0xF);
 
-    while mmio_read(MBOX_STATUS) & MBOX_STATUS_FULL != 0 {
+    while mmio_read::<u32>(MBOX_STATUS) & MBOX_STATUS_FULL != 0 {
         llvm_asm!("nop");
     }
 
@@ -93,11 +96,11 @@ unsafe fn call(ch: u32) -> Result<(), ()> {
     mmio_write(MBOX_WRITE, value);
 
     loop {
-        while mmio_read(MBOX_STATUS) & MBOX_STATUS_EMPTY != 0 {
+        while mmio_read::<u32>(MBOX_STATUS) & MBOX_STATUS_EMPTY != 0 {
             llvm_asm!("nop");
         }
 
-        if mmio_read(MBOX_READ) == value {
+        if mmio_read::<u32>(MBOX_READ) == value {
             if MESSAGE.data[1] == MBOX_RESPONSE {
                 return Ok(());
             } else {

kernel/src/arch/mach_bcm283x/mod.rs

@@ -4,7 +4,6 @@ use address::PhysicalAddress;
 pub mod aux;
 pub mod intc;
 pub mod mbox;
-pub mod smp;
 pub mod timer;
 
 pub const IRQ_LOCAL_TIMER: u32 = 1;

kernel/src/arch/mach_bcm283x/smp.rs

@@ -1,42 +0,0 @@
-use crate::{
-    arch::{cpu::CPU_COUNT, intrin},
-    mem::phys::{self, PageUsage},
-    KernelSpace,
-};
-use address::VirtualAddress;
-use core::hint;
-use core::sync::atomic::Ordering;
-
-pub const MAX_CPU: usize = 4;
-
-pub fn cpu_ready(_index: usize) {
-    CPU_COUNT.fetch_add(1, Ordering::SeqCst);
-}
-
-fn wakeup_single_ap() {
-    extern "C" {
-        static mut ap_wakeup_lock: u64;
-        static mut ap_init_value: u64;
-    }
-
-    let stack_bottom_phys = phys::alloc_contiguous_pages(PageUsage::Kernel, 4).unwrap();
-    let stack_bottom = VirtualAddress::<KernelSpace>::from(stack_bottom_phys);
-
-    let old_count = CPU_COUNT.load(Ordering::SeqCst);
-
-    unsafe {
-        core::ptr::write_volatile(&mut ap_init_value, stack_bottom.into());
-        intrin::dsb_sy();
-        core::ptr::write_volatile(&mut ap_wakeup_lock, 0);
-    }
-
-    while CPU_COUNT.load(Ordering::SeqCst) == old_count {
-        hint::spin_loop();
-    }
-}
-
-pub fn wakeup_ap_cpus() {
-    for _ in 1..4 {
-        wakeup_single_ap();
-    }
-}

kernel/src/arch/macros.S

@@ -28,62 +28,4 @@
 .set PAGE_ATTR_SHIFT,   2
 
 .set KERNEL_OFFSET, 0xFFFFFF8000000000
-
-.macro __exc_save_ctx
-    sub sp, sp, #192
-
-    stp x0, x1, [sp, #0]
-    stp x2, x3, [sp, #16]
-    stp x4, x5, [sp, #32]
-    stp x6, x7, [sp, #48]
-    stp x8, x9, [sp, #64]
-    stp x10, x11, [sp, #80]
-    stp x12, x13, [sp, #96]
-    stp x14, x15, [sp, #112]
-    stp x16, x17, [sp, #128]
-    stp x18, x29, [sp, #144]
-
-    mrs x0, elr_el1
-    stp x30, x0, [sp, #160]
-.endm
-
-.macro __exc_restore_ctx
-    ldp x30, x0, [sp, #160]
-    msr elr_el1, x0
-
-    ldp x0, x1, [sp, #0]
-    ldp x2, x3, [sp, #16]
-    ldp x4, x5, [sp, #32]
-    ldp x6, x7, [sp, #48]
-    ldp x8, x9, [sp, #64]
-    ldp x10, x11, [sp, #80]
-    ldp x12, x13, [sp, #96]
-    ldp x14, x15, [sp, #112]
-    ldp x16, x17, [sp, #128]
-    ldp x18, x29, [sp, #144]
-
-    add sp, sp, #192
-.endm
-
-.macro __callee_save_ctx
-    sub sp, sp, #96
-
-    stp x19, x20, [sp, #0]
-    stp x21, x22, [sp, #16]
-    stp x23, x24, [sp, #32]
-    stp x25, x26, [sp, #48]
-    stp x27, x29, [sp, #64]
-    stp xzr, lr, [sp, #80]
-.endm
-
-.macro __callee_restore_ctx
-    ldp x19, x20, [sp, #0]
-    ldp x21, x22, [sp, #16]
-    ldp x23, x24, [sp, #32]
-    ldp x25, x26, [sp, #48]
-    ldp x27, x29, [sp, #64]
-    ldp xzr, lr, [sp, #80]
-
-    add sp, sp, #96
-.endm
 .endif

kernel/src/arch/mod.rs

@@ -2,7 +2,6 @@ use crate::KernelSpace;
 use address::{PhysicalAddress, VirtualAddress};
 
 pub mod cpu;
-pub mod smp;
 pub mod exception;
 pub mod intrin;
 pub mod timer;
@@ -17,14 +16,21 @@ cfg_if! {
     }
 }
 
-pub unsafe fn mmio_write(addr: PhysicalAddress, value: u32) {
+pub trait MmioSize {}
+impl MmioSize for u32 {}
+impl MmioSize for i32 {}
+impl MmioSize for u8 {}
+
+#[inline]
+pub unsafe fn mmio_write<T: MmioSize>(addr: PhysicalAddress, value: T) {
     core::ptr::write_volatile(
         VirtualAddress::<KernelSpace>::from(addr).as_mut_ptr(),
         value,
     );
 }
 
-pub unsafe fn mmio_read(addr: PhysicalAddress) -> u32 {
+#[inline]
+pub unsafe fn mmio_read<T: MmioSize>(addr: PhysicalAddress) -> T {
     core::ptr::read_volatile(
         VirtualAddress::<KernelSpace>::from(addr).as_mut_ptr(),
     )

kernel/src/arch/smp.rs

@@ -1,99 +0,0 @@
-use crate::{
-    arch::{
-        cpu::{self, Cpu, CPU_COUNT},
-        intrin,
-    },
-    entry_common,
-};
-use core::sync::atomic::Ordering;
-
-pub trait IpiDelivery {
-    fn enable(&self);
-    fn send_ipi(target_id: u32, message: IpiMessage);
-}
-
-cfg_if! {
-    if #[cfg(feature = "mach_rpi3b")] {
-        use super::mach_bcm283x::{mbox, smp as smp_impl};
-
-        pub type IpiDeliveryImpl = mbox::CoreMailbox;
-        use mbox::CORE_MBOX0 as IPI_IMPL;
-    } else {
-        // Dummy SMP implementation
-        mod smp_impl {
-            use super::{IpiDelivery, IpiMessage};
-            pub const MAX_CPU: usize = 1;
-
-            pub struct IpiDeliveryImpl;
-
-            impl IpiDelivery for IpiDeliveryImpl {
-                fn enable(&self) {}
-                fn send_ipi(_target_id: u32, _message: IpiMessage) {}
-            }
-
-            pub(super) fn cpu_ready(_index: usize) {}
-            pub(super) fn wakeup_ap_cpus() {}
-
-            pub static IPI_IMPL: IpiDeliveryImpl = IpiDeliveryImpl;
-        }
-
-        pub use smp_impl::{IpiDeliveryImpl, IPI_IMPL};
-    }
-}
-
-pub use smp_impl::MAX_CPU;
-#[derive(Clone, Copy, PartialEq, Debug)]
-#[repr(u32)]
-pub enum IpiMessage {
-    Halt = 0,
-    Tick = 1,
-}
-
-#[no_mangle]
-extern "C" fn kernel_ap_main() -> ! {
-    let index = cpu::get_phys_id();
-    debugln!("cpu{}: ap wake up", index);
-    cpu::init(index);
-
-    smp_impl::cpu_ready(index);
-
-    entry_common();
-}
-
-pub unsafe fn send_ipi(mask: usize, message: IpiMessage) {
-    let self_index = Cpu::get().index();
-
-    for index in 0..CPU_COUNT.load(Ordering::Relaxed) {
-        if (1 << index) & mask != 0 && self_index != index as u32 {
-            // TODO cpus must be in phys order?
-            IpiDeliveryImpl::send_ipi(index as u32, message);
-        }
-    }
-}
-
-pub fn handle_ipi(message: IpiMessage) {
-    debugln!("cpu{} received ipi: {:?}", Cpu::get().index(), message);
-
-    match message {
-        IpiMessage::Halt => {
-            unsafe {
-                intrin::disable_irq();
-            }
-            loop {
-                unsafe {
-                    intrin::disable_irq();
-                }
-                intrin::nop();
-            }
-        }
-        IpiMessage::Tick => {}
-    }
-}
-
-pub fn wakeup_ap_cpus() {
-    smp_impl::wakeup_ap_cpus();
-}
-
-pub fn init_ipi_delivery() {
-    IPI_IMPL.enable();
-}

kernel/src/arch/timer.rs

@@ -1,5 +1,6 @@
 use crate::{
-    arch::{intrin, machine},
+    arch::{intrin, machine, cpu::Cpu},
+    proc::sched,
     dev::{
         irq::{self, InterruptController, InterruptHandler},
         Device,
@@ -24,9 +25,9 @@ impl Device for ArmTimer {
 
 impl InterruptHandler for ArmTimer {
     fn do_irq(&self, _irq: u32) {
-        debugln!("T");
         unsafe {
-            intrin::write_cntp_tval_el0(10000000);
+            sched::sched_yield();
+            intrin::write_cntp_tval_el0(100000);
         }
     }
 }

kernel/src/arch/vectors.S

@@ -1,5 +1,42 @@
+// vi:ft=asm :
 .include "kernel/src/arch/macros.S"
 
+.macro __exc_save_ctx
+    sub sp, sp, #192
+
+    stp x0, x1, [sp, #0]
+    stp x2, x3, [sp, #16]
+    stp x4, x5, [sp, #32]
+    stp x6, x7, [sp, #48]
+    stp x8, x9, [sp, #64]
+    stp x10, x11, [sp, #80]
+    stp x12, x13, [sp, #96]
+    stp x14, x15, [sp, #112]
+    stp x16, x17, [sp, #128]
+    stp x18, x29, [sp, #144]
+
+    mrs x0, elr_el1
+    stp x30, x0, [sp, #160]
+.endm
+
+.macro __exc_restore_ctx
+    ldp x30, x0, [sp, #160]
+    msr elr_el1, x0
+
+    ldp x0, x1, [sp, #0]
+    ldp x2, x3, [sp, #16]
+    ldp x4, x5, [sp, #32]
+    ldp x6, x7, [sp, #48]
+    ldp x8, x9, [sp, #64]
+    ldp x10, x11, [sp, #80]
+    ldp x12, x13, [sp, #96]
+    ldp x14, x15, [sp, #112]
+    ldp x16, x17, [sp, #128]
+    ldp x18, x29, [sp, #144]
+
+    add sp, sp, #192
+.endm
+
 .section .rodata
 .global el1_vectors
 .p2align 7

kernel/src/boot/entry.S

@@ -8,32 +8,9 @@ _entry:
     ands x1, x1, #3
     beq _entry_bsp
 
-1:
-    adr x8, ap_wakeup_lock
-    mov x9, #1
 _ap_loop:
-    // Will acquire exclusive access to [x8]
-    ldaxr x0, [x8]
-    // Will try to write 1 into [x8], failing if
-    // any other PE has acquired exclusive access at this point
-    stxr w1, x9, [x8]
-    // Store failed, jump back
-    cbnz w1, _ap_loop
-    // [x8] data wasn't zero, jump back
-    cbnz x0, _ap_loop
-_ap_wakeup:
-    adr x0, ap_init_value
-
-    mov x1, #KERNEL_OFFSET
-
-    // Kernel stack
-    ldr x10, [x0]
-
-    // Entry
-    adr x11, kernel_ap_main
-    add x11, x11, x1
-
-    b _entry_ap
+1:
+    b 1b
 
 .section .text
 _entry_bsp:
@@ -44,14 +21,21 @@ _entry_bsp:
     // Setup paging tables
     // This is done once for all PEs
     adr x0, kernel_l1
-    mov x1, #PAGE_PRESENT
-    orr x1, x1, #PAGE_ACCESSED
-    orr x1, x1, #PAGE_ISH
+
+    mov x2, #PAGE_PRESENT
+    orr x2, x2, #PAGE_ACCESSED
+    orr x2, x2, #PAGE_ISH
+
+    mov x1, x2
     str x1, [x0]
 
-    orr x1, x1, #1 << 30
+    orr x1, x2, #1 << 30
     str x1, [x0, #8]
 
+    ldr x1, =0x4010000000
+    orr x1, x2, x1
+    str x1, [x0, #16]
+
     // Load BSP stack
     mov x0, #KERNEL_OFFSET
     adr x10, bsp_stack_top

kernel/src/debug.rs

@@ -1,6 +1,9 @@
-use crate::dev::serial::{SerialDevice, SERIAL0};
+use crate::{
+    arch::intrin,
+    dev::serial::{SerialDevice, SERIAL0},
+    sync::Spin as Mutex,
+};
 use core::fmt;
-use spin::Mutex;
 
 struct Debug;
 
@@ -33,5 +36,9 @@ macro_rules! debugln {
 
 pub fn debug_fmt(args: fmt::Arguments<'_>) {
     use fmt::Write;
+    let u = unsafe { intrin::save_irq() };
     write!(DEBUG.lock(), "{}", args).unwrap();
+    unsafe {
+        intrin::restore_irq(u);
+    }
 }

kernel/src/dev/irq.rs

@@ -74,7 +74,7 @@ cfg_if! {
         pub fn get_intc() -> &'static impl InterruptController {
             &INTC
         }
-    } else {
+    } else if #[cfg(feature = "mach_virt")] {
         pub mod gic;
         use gic::Gic;
         use crate::arch::machine;

kernel/src/dev/irq/gic.rs

@@ -37,7 +37,7 @@ impl InterruptController for Gic {
 
     fn is_irq_pending(&self, irq: u32) -> bool {
         unsafe {
-            mmio_read(self.gicd_base + Self::GICD_ICPENDR + ((irq >> 3) & !0x3) as usize)
+            mmio_read::<u32>(self.gicd_base + Self::GICD_ICPENDR + ((irq >> 3) & !0x3) as usize)
                 & (1 << (irq & 0x1F))
                 != 0
         }

kernel/src/dev/mod.rs

@@ -3,6 +3,8 @@ pub mod serial;
 
 pub mod pl011;
 pub mod pl031;
+pub mod virtio;
+pub mod pcie;
 
 pub trait Device {
     fn name(&self) -> &'static str;

kernel/src/dev/pcie.rs

@@ -0,0 +1,58 @@
+use crate::{arch::mmio_read, dev::Device, mem::EcamSpace};
+use address::{PhysicalAddress, VirtualAddress};
+use core::ops::Index;
+
+pub struct HostPci {
+    base: PhysicalAddress,
+}
+
+pub struct PcieFunctionConfig {
+    base: PhysicalAddress,
+}
+
+impl Device for HostPci {
+    fn name(&self) -> &'static str {
+        "Host PCI(e) Controller"
+    }
+
+    unsafe fn enable(&self) {
+        let func = PcieFunctionConfig { base: self.base };
+        debugln!("{:#010x}", func.readl(0));
+        debugln!(":");
+    }
+
+    unsafe fn disable(&self) {}
+}
+
+impl HostPci {
+    pub const fn new(base: PhysicalAddress) -> Self {
+        Self { base }
+    }
+}
+
+impl PcieFunctionConfig {
+    #[inline(always)]
+    pub unsafe fn readl(&self, off: usize) -> u32 {
+        let addr = VirtualAddress::<EcamSpace>::from(self.base + off);
+        core::ptr::read_volatile(addr.as_ptr())
+    }
+
+    #[inline(always)]
+    pub unsafe fn readw(&self, off: usize) -> u16 {
+        (self.readl(off & !0x3) | (0xFFFF << (off & 0x3))) as u16
+    }
+
+    #[inline(always)]
+    pub fn device_id(&self) -> u16 {
+        unsafe { self.readw(2) }
+    }
+
+    #[inline(always)]
+    pub fn vendor_id(&self) -> u16 {
+        unsafe { self.readw(0) }
+    }
+}
+
+pub const fn func_offset(bus: u8, dev: u8, func: u8) -> usize {
+    ((bus as usize) << 20) | ((dev as usize) << 15) | ((func as usize) << 12)
+}

kernel/src/dev/pl011.rs

@@ -10,10 +10,9 @@ pub struct Pl011 {
 
 impl InterruptHandler for Pl011 {
     fn do_irq(&self, _irq: u32) {
-        let tmp = unsafe { mmio_read(self.base + Self::UARTRIS) };
+        let tmp: u32 = unsafe { mmio_read(self.base + Self::UARTRIS) };
         if tmp & Self::UARTRIS_RXRIS != 0 {
-            let ch = unsafe { mmio_read(self.base + Self::UARTDR) } as u8;
-            debugln!("{}", ch as char);
+            let _ch = unsafe { mmio_read::<u32>(self.base + Self::UARTDR) } as u8;
             unsafe {
                 mmio_write(self.base + Self::UARTICR, Self::UARTICR_RXIC);
             }
@@ -45,7 +44,7 @@ impl Device for Pl011 {
 impl SerialDevice for Pl011 {
     fn send(&self, ch: u8) {
         unsafe {
-            while mmio_read(self.base + Self::UARTFR) & Self::UARTFR_BUSY != 0 {}
+            while mmio_read::<u32>(self.base + Self::UARTFR) & Self::UARTFR_BUSY != 0 {}
             mmio_write(self.base + Self::UARTDR, ch as u32);
         }
     }

kernel/src/dev/pl031.rs

@@ -26,7 +26,7 @@ impl Device for Pl031 {
     }
 
     unsafe fn enable(&self) {
-        let tmp = mmio_read(self.base + Self::RTCDR);
+        let tmp: u32 = mmio_read(self.base + Self::RTCDR);
         mmio_write(self.base + Self::RTCMR, tmp + 1);
 
         mmio_write(self.base + Self::RTCIMSC, 1);
@@ -38,7 +38,7 @@ impl Device for Pl031 {
 
 impl InterruptHandler for Pl031 {
     fn do_irq(&self, _irq: u32) {
-        let time_int = unsafe { mmio_read(self.base + Self::RTCDR) };
+        let time_int: u32 = unsafe { mmio_read(self.base + Self::RTCDR) };
         unsafe {
             mmio_write(self.base + Self::RTCICR, 1);
             mmio_write(self.base + Self::RTCMR, time_int + 1);

kernel/src/dev/virtio.rs

@@ -0,0 +1,25 @@
+use crate::dev::Device;
+use address::PhysicalAddress;
+
+pub struct Display {
+    base: PhysicalAddress
+}
+
+impl Device for Display {
+    fn name(&self) -> &'static str {
+        "VirtIO GPU"
+    }
+
+    unsafe fn enable(&self) {
+    }
+
+    unsafe fn disable(&self) {
+
+    }
+}
+
+impl Display {
+    pub const fn new(base: PhysicalAddress) -> Self {
+        Self { base }
+    }
+}

kernel/src/fdt.rs

@@ -9,7 +9,7 @@ use address::{PhysicalAddress, VirtualAddress};
 use core::mem::MaybeUninit;
 use fdt_rs::{
     base::{DevTree, DevTreeProp},
-    index::DevTreeIndex,
+    index::{DevTreeIndex, DevTreeIndexNode, DevTreeIndexProp},
     prelude::*,
 };
 
@@ -17,10 +17,72 @@ use fdt_rs::{
 struct FdtManager {
     fdt: DevTree<'static>,
     index: DevTreeIndex<'static, 'static>,
+    address_cells: u32,
+    size_cells: u32,
+}
+
+impl FdtManager {
+    fn dump(&self) {
+        self.dump_node(&self.index.root(), 0);
+    }
+
+    fn dump_node(&self, node: &DevTreeIndexNode, depth: usize) {
+        for _ in 0..depth {
+            debug!(" ");
+        }
+        debugln!("\"{}\" {{", node.name().unwrap());
+
+        for prop in node.props() {
+            for _ in 0..=depth {
+                debug!(" ");
+            }
+            let name = prop.name().unwrap();
+            debug!("\"{}\" = ", name);
+            match name {
+                "compatible" => debug!("\"{}\"", prop.str().unwrap()),
+                "#size-cells" | "#address-cells" => debug!("{}", prop.u32(0).unwrap()),
+                "reg" => {
+                    debug!("<");
+                    for i in 0..prop.length() / 4 {
+                        debug!("{:#010x}", prop.u32(i).unwrap());
+                        if i != prop.length() / 4 - 1 {
+                            debug!(", ");
+                        }
+                    }
+                    debug!(">");
+                }
+                _ => debug!("..."),
+            }
+            debugln!(";");
+        }
+
+        for child in node.children() {
+            self.dump_node(&child, depth + 1);
+        }
+
+        for _ in 0..depth {
+            debug!(" ");
+        }
+        debugln!("}}");
+    }
 }
 
 static mut FDT_MANAGER: MaybeUninit<FdtManager> = MaybeUninit::uninit();
 
+fn read_cell_index_prop(prop: &DevTreeIndexProp, offset: usize, cells: u32) -> Option<usize> {
+    if cells == 2 {
+        // Read as two u32s
+        let high = prop.u32(offset).ok()? as usize;
+        let low = prop.u32(offset + 1).ok()? as usize;
+
+        Some(low | (high << 32))
+    } else {
+        let val = prop.u32(offset).ok()?;
+
+        Some(val as usize)
+    }
+}
+
 fn read_cell_prop(prop: &DevTreeProp, offset: usize, cells: u32) -> Option<usize> {
     if cells == 2 {
         // Read as two u32s
@@ -47,8 +109,25 @@ pub fn init(fdt_base_phys: PhysicalAddress) {
     let index =
         DevTreeIndex::new(fdt, unsafe { pages_virt.as_slice_mut(page_count * 0x1000) }).unwrap();
 
+    let root = index.root();
+    let mut address_cells = None;
+    let mut size_cells = None;
+    for prop in root.props() {
+        match prop.name().unwrap() {
+            "#address-cells" => address_cells = Some(prop.u32(0).unwrap()),
+            "#size-cells" => size_cells = Some(prop.u32(0).unwrap()),
+            _ => {}
+        }
+    }
+
     unsafe {
-        FDT_MANAGER.write(FdtManager { fdt, index });
+        FDT_MANAGER.write(FdtManager {
+            address_cells: address_cells.unwrap(),
+            size_cells: size_cells.unwrap(),
+            fdt,
+            index,
+        });
+        FDT_MANAGER.assume_init_ref().dump();
     }
 }
 

kernel/src/main.rs

@@ -3,7 +3,8 @@
     llvm_asm,
     const_panic,
     maybe_uninit_uninit_array,
-    alloc_error_handler
+    alloc_error_handler,
+    const_fn_trait_bound
 )]
 #![no_std]
 #![no_main]
@@ -22,24 +23,16 @@ pub mod dev;
 pub mod fdt;
 pub mod mem;
 pub mod time;
+pub mod proc;
+pub mod sync;
 
 pub use mem::KernelSpace;
 
 use address::PhysicalAddress;
-use arch::{timer, cpu, intrin, smp};
+use arch::{timer, cpu, intrin};
 use dev::irq::{self, InterruptController};
-
-pub fn entry_common() -> ! {
-    smp::init_ipi_delivery();
-
-    unsafe {
-        irq::init();
-        timer::enable_local_timer();
-        intrin::enable_irq();
-    }
-
-    loop {}
-}
+use dev::virtio::Display;
+use dev::pcie::HostPci;
 
 #[no_mangle]
 extern "C" fn kernel_bsp_main(fdt_base: PhysicalAddress) -> ! {
@@ -67,8 +60,20 @@ extern "C" fn kernel_bsp_main(fdt_base: PhysicalAddress) -> ! {
     }
 
     debug!("BSP init finished\n");
-    //smp::wakeup_ap_cpus();
-    entry_common();
+    unsafe {
+        irq::init();
+        timer::enable_local_timer();
+    }
+
+    let mut bus = HostPci::new(PhysicalAddress::new(0x10000000));
+    unsafe {
+        use dev::Device;
+        bus.enable();
+    }
+    //let mut display = Display::new();
+
+    loop {}
+    //proc::enter();
 }
 
 use core::panic::PanicInfo;
@@ -78,8 +83,5 @@ fn panic_handler(pi: &PanicInfo) -> ! {
         intrin::disable_irq();
     }
     debug!("PANIC: {:?}\n", pi);
-    unsafe {
-        smp::send_ipi(usize::MAX, smp::IpiMessage::Halt);
-    }
     loop {}
 }

kernel/src/mem/heap.rs

@@ -10,7 +10,7 @@ use crate::{
 use address::VirtualAddress;
 use core::alloc::{GlobalAlloc, Layout};
 use core::convert::TryFrom;
-use core::mem::{size_of, MaybeUninit};
+use core::mem::size_of;
 use core::ptr::null_mut;
 use spin::Mutex;
 
@@ -19,7 +19,7 @@ const HEAP_SIZE: usize = 16 << 20; // 16MiB
 
 struct Heap {
     start: VirtualAddress<KernelSpace>,
-    mutex: MaybeUninit<Mutex<()>>,
+    mutex: Option<Mutex<()>>,
 }
 
 #[derive(Debug)]
@@ -37,7 +37,7 @@ unsafe impl GlobalAlloc for Heap {
         let count = ((layout.size() + 15) & !15) as u32;
 
         // NOTE: that shouldn't be optimized away
-        let _lock = self.mutex.assume_init_ref().lock();
+        let _lock = self.mutex.as_ref().unwrap().lock();
 
         // Check if the memory is corrupted
         let mut block_it = self.first();
@@ -71,7 +71,7 @@ unsafe impl GlobalAlloc for Heap {
 
     unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
         // NOTE: that shouldn't be optimized away
-        let _lock = self.mutex.assume_init_ref().lock();
+        let _lock = self.mutex.as_ref().unwrap().lock();
         let address = VirtualAddress::from_ptr(ptr);
 
         // Check heap boundaries
@@ -124,7 +124,7 @@ impl Heap {
         block.next = null_mut();
         Heap {
             start: addr,
-            mutex: MaybeUninit::new(Mutex::new(())),
+            mutex: Some(Mutex::new(())),
         }
     }
 
@@ -135,7 +135,7 @@ impl Heap {
     #[allow(dead_code)]
     fn dump(&self) {
         // NOTE: that shouldn't be optimized away
-        let _lock = unsafe { self.mutex.assume_init_ref().lock() };
+        let _lock = self.mutex.as_ref().unwrap().lock();
 
         let mut block_it = self.first();
         while let Some(ref mut block) = block_it {
@@ -187,7 +187,7 @@ impl HeapBlock {
 #[global_allocator]
 static mut KERNEL_HEAP: Heap = Heap {
     start: VirtualAddress::null(),
-    mutex: MaybeUninit::uninit(),
+    mutex: None,
 };
 
 #[alloc_error_handler]

kernel/src/mem/mod.rs

@@ -12,6 +12,15 @@ impl AddressSpace for KernelSpace {
 }
 impl TrivialConvert for KernelSpace {}
 
+#[derive(Copy, Clone, PartialEq, PartialOrd)]
+pub struct EcamSpace;
+impl AddressSpace for EcamSpace {
+    const NAME: &'static str = "ecam";
+    const OFFSET: usize = 0xFFFFFF8080000000;
+    const LIMIT: usize = 0xFFFFFF8080000000 + (1 << 30);
+}
+impl TrivialConvert for EcamSpace {}
+
 pub const PAGE_SIZE: usize = 0x1000;
 
 pub fn kernel_end_phys() -> PhysicalAddress {

kernel/src/mem/phys/manager.rs

@@ -2,8 +2,8 @@ use super::{PageInfo, PageUsage};
 use crate::{mem::PAGE_SIZE, KernelSpace};
 use address::{PhysicalAddress, VirtualAddress};
 use core::mem;
-use error::Errno;
 use spin::Mutex;
+use error::Errno;
 
 pub unsafe trait Manager {
     fn alloc_page(&mut self, pu: PageUsage) -> Result<PhysicalAddress, Errno>;
@@ -18,7 +18,7 @@ pub unsafe trait Manager {
 }
 
 pub struct SimpleManager {
-    pages: &'static mut [Mutex<PageInfo>],
+    pages: &'static mut [PageInfo],
     base_index: usize,
 }
 
@@ -28,17 +28,17 @@ impl SimpleManager {
         at: PhysicalAddress,
         count: usize,
     ) -> Self {
-        let pages: &'static mut [Mutex<PageInfo>] =
+        let pages: &'static mut [PageInfo] =
             VirtualAddress::<KernelSpace>::from(at).as_slice_mut(count);
 
         // Initialize uninit pages
         for index in 0..count {
             mem::forget(mem::replace(
                 &mut pages[index],
-                Mutex::new(PageInfo {
+                PageInfo {
                     refcount: 0,
                     usage: PageUsage::Reserved,
-                }),
+                },
             ));
         }
 
@@ -49,7 +49,7 @@ impl SimpleManager {
     }
 
     pub(super) unsafe fn add_page(&mut self, addr: PhysicalAddress) {
-        let mut page = self.pages[addr.page_index() - self.base_index].lock();
+        let page = &mut self.pages[addr.page_index() - self.base_index];
         assert!(page.refcount == 0 && page.usage == PageUsage::Reserved);
         page.usage = PageUsage::Available;
 
@@ -62,7 +62,7 @@ impl SimpleManager {
 unsafe impl Manager for SimpleManager {
     fn alloc_page(&mut self, pu: PageUsage) -> Result<PhysicalAddress, Errno> {
         for index in 0..self.pages.len() {
-            let mut page = self.pages[index].lock();
+            let page = &mut self.pages[index];
 
             if page.usage == PageUsage::Available {
                 page.usage = pu;
@@ -79,13 +79,13 @@ unsafe impl Manager for SimpleManager {
     ) -> Result<PhysicalAddress, Errno> {
         'l0: for i in 0..self.pages.len() {
             for j in 0..count {
-                if self.pages[i + j].lock().usage != PageUsage::Available {
+                if self.pages[i + j].usage != PageUsage::Available {
                     continue 'l0;
                 }
             }
 
             for j in 0..count {
-                let mut page = self.pages[i + j].lock();
+                let page = &mut self.pages[i + j];
                 assert!(page.usage == PageUsage::Available);
                 page.usage = pu;
                 page.refcount = 1;

kernel/src/mem/phys/mod.rs

@@ -1,4 +1,5 @@
 use super::PAGE_SIZE;
+use core::panic::Location;
 use address::PhysicalAddress;
 use core::convert::TryFrom;
 use core::mem::size_of;

kernel/src/proc/context.S

@@ -1,9 +1,30 @@
-.include "kernel/src/arch/macros.S"
-
 .section .text
+.global context_enter_kernel
 .global context_switch_to
 .global context_switch
 
+.macro __callee_save_ctx
+    sub sp, sp, #96
+
+    stp x19, x20, [sp, #0]
+    stp x21, x22, [sp, #16]
+    stp x23, x24, [sp, #32]
+    stp x25, x26, [sp, #48]
+    stp x27, x29, [sp, #64]
+    stp xzr, lr, [sp, #80]
+.endm
+
+.macro __callee_restore_ctx
+    ldp x19, x20, [sp, #0]
+    ldp x21, x22, [sp, #16]
+    ldp x23, x24, [sp, #32]
+    ldp x25, x26, [sp, #48]
+    ldp x27, x29, [sp, #64]
+    ldp xzr, lr, [sp, #80]
+
+    add sp, sp, #96
+.endm
+
 context_enter_kernel:
     mov x0, #5
     msr spsr_el1, x0
@@ -14,10 +35,10 @@ context_enter_kernel:
 context_switch:
     msr daifset, #0xF
 
-    // Store old callee-saved regs on stack
+    // Store old callee-saved regs
     __callee_save_ctx
 
-    // Store old stack pointer
+    // Store old stack
     mov x19, sp
     str x19, [x1]
 context_switch_to:
@@ -27,8 +48,7 @@ context_switch_to:
     ldr x0, [x0]
     mov sp, x0
 
-    // Load new callee-saved regs on stack
+    // Load new callee-saved regs from stack
     __callee_restore_ctx
 
-    // Simulate/perform a return
     ret

kernel/src/proc/context.rs

@@ -1,72 +1,68 @@
-use crate::{
-    mem::phys::{self, PageUsage},
-    KernelSpace,
-};
-use address::VirtualAddress;
-use core::mem::size_of;
+use crate::{KernelSpace, mem::phys::{self, PageUsage}};
+use address::{VirtualAddress};
 
 global_asm!(include_str!("context.S"));
 
 #[repr(C)]
-pub(super) struct Context {
-    pub kernel_sp: VirtualAddress<KernelSpace>, // 0x00
-    cpu_id: u32,                                // 0x08
+pub struct Context {
+    sp: VirtualAddress<KernelSpace>,      // 0x00
 }
 
-struct StackBuilder {
+struct WriteStack {
     bp: VirtualAddress<KernelSpace>,
-    sp: VirtualAddress<KernelSpace>,
-}
-
-impl Context {
-    pub fn new_kernel(entry: usize, arg: usize) -> Context {
-        let kstack_phys = phys::alloc_contiguous_pages(PageUsage::Kernel, 4).unwrap();
-        let mut stack = unsafe { StackBuilder::new(kstack_phys.into(), 4096 * 4) };
-
-        debug!("Stack bounds: {:?}..{:?}\n", stack.sp, stack.bp);
-
-        stack.push(entry); // ELR before ERET
-        stack.push(arg);
-
-        stack.push(context_enter_kernel as usize); // x30 LR
-        stack.push(0usize); // padding
-        stack.push(0usize); // x29
-        stack.push(0usize); // x27
-        stack.push(0usize); // x26
-        stack.push(0usize); // x25
-        stack.push(0usize); // x24
-        stack.push(0usize); // x23
-        stack.push(0usize); // x22
-        stack.push(0usize); // x21
-        stack.push(0usize); // x20
-        stack.push(0usize); // x19
-
-        Context {
-            kernel_sp: stack.sp,
-            cpu_id: u32::MAX,
-        }
-    }
-}
-
-impl StackBuilder {
-    pub unsafe fn new(bp: VirtualAddress<KernelSpace>, size: usize) -> Self {
-        Self { bp, sp: bp + size }
-    }
-
-    pub fn push<A: Into<usize>>(&mut self, value: A) {
-        if self.sp == self.bp {
-            panic!("Stack overflow");
-        }
-        self.sp -= size_of::<usize>();
-        unsafe {
-            core::ptr::write(self.sp.as_mut_ptr(), value.into());
-        }
-    }
+    sp: VirtualAddress<KernelSpace>
 }
 
 extern "C" {
+    fn context_enter_kernel();
+
     pub(super) fn context_switch_to(dst: *mut Context);
     pub(super) fn context_switch(dst: *mut Context, src: *mut Context);
-
-    fn context_enter_kernel();
+}
+
+impl Context {
+    pub fn new_kernel(entry: usize, arg: usize) -> Self {
+        let pages = phys::alloc_contiguous_pages(PageUsage::Kernel, 4).unwrap();
+        let stack_bottom = VirtualAddress::<KernelSpace>::from(pages);
+        let mut stack = WriteStack::new(stack_bottom, 4 * 4096);
+
+        stack.push(entry);
+        stack.push(arg);
+
+        stack.push(context_enter_kernel as usize);      // x30 LR
+        stack.push(0);                                  // xzr
+        stack.push(0);                                  // x29
+        stack.push(0);                                  // x27
+        stack.push(0);                                  // x26
+        stack.push(0);                                  // x25
+        stack.push(0);                                  // x24
+        stack.push(0);                                  // x23
+        stack.push(0);                                  // x22
+        stack.push(0);                                  // x21
+        stack.push(0);                                  // x20
+        stack.push(0);                                  // x19
+
+        Context {
+            sp: stack.sp,
+        }
+    }
+}
+
+impl WriteStack {
+    pub fn new(bottom: VirtualAddress<KernelSpace>, size: usize) -> Self {
+        Self {
+            bp: bottom,
+            sp: bottom + size,
+        }
+    }
+
+    pub fn push(&mut self, value: usize) {
+        if self.sp == self.bp {
+            panic!("Stack overflow");
+        }
+        self.sp -= 8;
+        unsafe {
+            core::ptr::write(self.sp.as_mut_ptr(), value);
+        }
+    }
 }

kernel/src/proc/mod.rs

@@ -1,265 +1,72 @@
-use crate::arch::{
-    cpu::{self, get_cpu},
-    intrin,
+use crate::{
+    arch::{cpu::Cpu, intrin},
 };
 use core::mem::MaybeUninit;
 use core::ptr::null_mut;
-use core::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
+use core::sync::atomic::{AtomicU32, Ordering};
 use spin::Mutex;
 
 pub mod context;
-use context::{context_switch, context_switch_to, Context};
+pub mod sched;
 
+pub use context::Context;
+pub use sched::Scheduler;
+
+#[repr(C)]
 pub struct Process {
     context: Context,
-    cpu: Option<u32>,
 
-    sched_prev: *mut Process,
-    sched_next: *mut Process,
-}
+    id: u32,
+    cpu_id: Option<u32>,
 
-pub struct Queue {
-    head: *mut Process,
-    current: *mut Process,
-    size: usize,
-}
-
-pub struct Scheduler {
-    queue: Mutex<Queue>,
-    ready: AtomicBool,
-    idle: MaybeUninit<Process>,
+    queue_prev: *mut Process,
+    queue_next: *mut Process,
 }
 
 impl Process {
-    fn new_kernel(entry: usize, arg: usize) -> Self {
+    pub fn new_kernel(entry: usize, arg: usize) -> Self {
         Self {
             context: Context::new_kernel(entry, arg),
-            cpu: None,
 
-            sched_prev: null_mut(),
-            sched_next: null_mut(),
-        }
-    }
+            id: new_pid(),
+            cpu_id: None,
 
-    pub fn exit(&mut self) -> ! {
-        unsafe {
-            get_cpu().scheduler.unqueue(self);
-        }
-        panic!("This code should not run");
-    }
-
-    pub fn this() -> &'static mut Process {
-        // TODO Process can be rescheduled to some other CPU after/during this call
-        unsafe { &mut *get_cpu().scheduler.queue.lock().current }
-    }
-}
-
-impl Scheduler {
-    pub fn new() -> Self {
-        Self {
-            queue: Mutex::new(Queue {
-                head: null_mut(),
-                current: null_mut(),
-                size: 0,
-            }),
-            ready: AtomicBool::new(false),
-            idle: MaybeUninit::uninit(),
-        }
-    }
-
-    unsafe fn queue(&mut self, proc: *mut Process) {
-        let mut lock = self.queue.lock();
-
-        if !lock.head.is_null() {
-            let queue_tail = (*lock.head).sched_prev;
-            (*queue_tail).sched_next = proc;
-            (*proc).sched_prev = queue_tail;
-            (*lock.head).sched_prev = proc;
-            (*proc).sched_next = lock.head;
-        } else {
-            (*proc).sched_prev = proc;
-            (*proc).sched_next = proc;
-            lock.head = proc;
-        }
-
-        lock.size += 1;
-    }
-
-    unsafe fn unqueue(&mut self, proc: *mut Process) {
-        intrin::disable_irq();
-        let mut lock = self.queue.lock();
-        assert!((*proc).cpu.unwrap() == get_cpu().cpu_id);
-
-        // Can only unqueue current task
-        let sched_prev = (*proc).sched_prev;
-        let sched_next = (*proc).sched_next;
-
-        (*proc).sched_next = null_mut();
-        (*proc).sched_prev = null_mut();
-
-        if sched_next == proc {
-            lock.head = null_mut();
-            drop(lock);
-            let ptr = self.idle.as_mut_ptr();
-            self.switch_to(ptr);
-            panic!("This code should not run (yet)");
-        }
-
-        if proc == lock.head {
-            lock.head = sched_next;
-        }
-
-        (*sched_next).sched_prev = sched_prev;
-        (*sched_prev).sched_next = sched_next;
-
-        drop(lock);
-        self.switch_to(sched_next);
-    }
-
-    unsafe fn switch_to(&mut self, proc: *mut Process) {
-        intrin::disable_irq();
-        let mut lock = self.queue.lock();
-        let from = lock.current;
-        lock.current = proc;
-        (*proc).cpu = Some(get_cpu().cpu_id);
-
-        if from.is_null() {
-            drop(lock);
-            context_switch_to(&mut (*proc).context);
-        } else {
-            drop(lock);
-            context_switch(&mut (*proc).context, &mut (*from).context);
-        }
-    }
-
-    unsafe fn enter(&mut self) -> ! {
-        let lock = self.queue.lock();
-        self.ready.store(true, Ordering::Release);
-
-        let proc = if let Some(first) = lock.head.as_mut() {
-            first
-        } else {
-            self.idle.as_mut_ptr()
-        };
-        drop(lock);
-        self.switch_to(proc);
-
-        panic!("This code should not run");
-    }
-
-    unsafe fn init_idle(&mut self) {
-        self.idle.write(Process::new_kernel(idle_fn as usize, 0));
-    }
-
-    unsafe fn sched(&mut self) {
-        let mut lock = self.queue.lock();
-
-        let from = lock.current;
-        assert!(!from.is_null());
-        let from = &mut *from;
-
-        let to = if !from.sched_next.is_null() {
-            from.sched_next
-        } else if !lock.head.is_null() {
-            lock.head
-        } else {
-            self.idle.as_mut_ptr()
-        };
-
-        assert!(!to.is_null());
-
-        drop(lock);
-
-        self.switch_to(to);
-    }
-}
-
-fn idle_fn(_arg: usize) {
-    loop {
-        unsafe {
-            intrin::enable_irq();
-            intrin::wfi();
+            queue_prev: null_mut(),
+            queue_next: null_mut(),
         }
     }
 }
 
-pub fn sched_yield() {
-    let cpu = get_cpu();
-    if cpu.scheduler.ready.load(Ordering::Acquire) {
-        unsafe {
-            cpu.scheduler.sched();
-        }
-    }
-}
-
-pub fn sched_queue(proc: *mut Process) {
-    let mut min_idx = 0;
-    let mut min_val = usize::MAX;
-    for index in 0..cpu::CPU_COUNT.load(Ordering::Relaxed) {
-        let lock = unsafe { cpu::CPUS[index].assume_init_ref().scheduler.queue.lock() };
-        if lock.size < min_val {
-            min_idx = index;
-            min_val = lock.size;
-        }
-    }
-
-    debugln!("Queue to cpu{}", min_idx);
-    unsafe {
-        cpu::CPUS[min_idx].assume_init_mut().scheduler.queue(proc);
-    };
-}
-
-#[inline(never)]
-fn make_delay(d: usize) {
-    for _ in 0..d {
-        crate::arch::intrin::nop();
-    }
+pub fn new_pid() -> u32 {
+    LAST_PID.fetch_add(1, Ordering::SeqCst)
 }
 
 extern "C" fn f0(arg: usize) {
-    for _ in 0..600 + arg * 600 {
-        make_delay(10000);
-
-        unsafe {
-            COUNTERS[arg]
-                .assume_init_mut()
-                .fetch_add(1, Ordering::Relaxed);
-        }
-    }
-
-    debugln!("Exit task #{}", arg);
-    Process::this().exit();
-}
-
-pub static mut COUNTERS: [MaybeUninit<AtomicUsize>; cpu::MAX_CPU * 2] = MaybeUninit::uninit_array();
-static TASK_COUNT: AtomicUsize = AtomicUsize::new(0);
-static mut C: [MaybeUninit<Process>; cpu::MAX_CPU * 2] = MaybeUninit::uninit_array();
-
-pub fn spawn_task() {
-    let c = TASK_COUNT.load(Ordering::Acquire);
-    if c >= unsafe { COUNTERS.len() } {
-        return;
-    }
-    TASK_COUNT.fetch_add(1, Ordering::Release);
-    unsafe {
-        debugln!("Start task #{}", c);
-        COUNTERS[c].write(AtomicUsize::new(0));
-        C[c].write(Process::new_kernel(f0 as usize, c));
-        sched_queue(C[c].assume_init_mut());
+    loop {
+        debug!("{}", arg);
     }
 }
 
+static LAST_PID: AtomicU32 = AtomicU32::new(1);
+static mut S: [MaybeUninit<Process>; 2] = MaybeUninit::uninit_array();
+
 pub fn enter() -> ! {
     unsafe {
-        let cpu = get_cpu();
+        //let mut cpu = Cpu::get();
+        //cpu.scheduler.init();
+        let mut sched = Scheduler::get();
 
-        debug!("Setting up a task for cpu{}\n", cpu.cpu_id);
-        let id = cpu.cpu_id as usize;
+        S[0].write(Process::new_kernel(f0 as usize, 0));
+        S[1].write(Process::new_kernel(f0 as usize, 1));
 
-        // Initialize the idle task
-        cpu.scheduler.init_idle();
+        sched.queue(S[0].as_mut_ptr());
+        //cpu.scheduler.queue(S[0].as_mut_ptr());
+        intrin::delay(4000);
+        sched.queue(S[1].as_mut_ptr());
+        //cpu.scheduler.queue(S[1].as_mut_ptr());
 
-        debug!("Entering scheduler on cpu{}\n", cpu.cpu_id);
-        cpu.scheduler.enter();
+        sched.enter();
+        //cpu.scheduler.enter();
     }
+    loop {}
 }

kernel/src/proc/sched.rs

@@ -0,0 +1,174 @@
+use crate::{
+    arch::{cpu, intrin},
+    proc::{
+        context::{context_switch, context_switch_to},
+        Process,
+    },
+    sync::Spin as Mutex
+};
+use core::mem::MaybeUninit;
+use core::ptr::null_mut;
+use core::sync::atomic::{AtomicBool, Ordering};
+
+pub struct Queue {
+    head: *mut Process,
+    current: *mut Process,
+    size: usize,
+}
+
+pub struct Scheduler {
+    queue: Mutex<Queue>,
+    ready: AtomicBool,
+    idle: MaybeUninit<Process>,
+    cpu_index: usize,
+}
+
+impl Queue {
+    pub const fn new() -> Self {
+        Self {
+            head: null_mut(),
+            current: null_mut(),
+            size: 0,
+        }
+    }
+}
+
+impl Scheduler {
+    pub const fn new() -> Self {
+        Self {
+            queue: Mutex::new(Queue::new()),
+            ready: AtomicBool::new(false),
+            idle: MaybeUninit::uninit(),
+            cpu_index: 0,
+        }
+    }
+
+    pub unsafe fn init(&mut self) {
+        self.idle.write(Process::new_kernel(idle_fn as usize, 0));
+    }
+
+    pub fn is_ready(&self) -> bool {
+        self.ready.load(Ordering::Acquire)
+    }
+
+    pub fn queue(&mut self, proc: *mut Process) {
+        let irq_state = unsafe { intrin::save_irq() };
+        let mut queue = self.queue.lock();
+
+        unsafe {
+            if !queue.head.is_null() {
+                let queue_tail = (*queue.head).queue_prev;
+                (*queue_tail).queue_next = proc;
+                (*proc).queue_prev = queue_tail;
+                (*queue.head).queue_prev = proc;
+                (*proc).queue_next = queue.head;
+            } else {
+                (*proc).queue_prev = proc;
+                (*proc).queue_next = proc;
+                queue.head = proc;
+            }
+        }
+
+        queue.size += 1;
+        unsafe {
+            intrin::restore_irq(irq_state);
+        }
+    }
+
+    pub unsafe fn switch_to(&mut self, dst: *mut Process) {
+        intrin::disable_irq();
+
+        let mut queue = self.queue.lock();
+        let src = queue.current;
+
+        if src == dst {
+            return;
+        }
+        assert!((*dst).cpu_id.is_none());
+
+        queue.current = dst;
+        (*dst).cpu_id = Some(self.cpu_index as u32);
+
+        if src.is_null() {
+            drop(queue);
+            context_switch_to(&mut (*dst).context);
+        } else {
+            (*src).cpu_id = None;
+            drop(queue);
+            context_switch(&mut (*dst).context, &mut (*src).context);
+        }
+    }
+
+    pub unsafe fn enter(&mut self) -> ! {
+        intrin::disable_irq();
+
+        let queue = self.queue.lock();
+        self.ready.store(true, Ordering::Release);
+
+        let initial = if let Some(first) = queue.head.as_mut() {
+            first
+        } else {
+            self.idle.as_mut_ptr()
+        };
+
+        drop(queue);
+        debugln!("cpu{}: N -> {:p}", self.cpu_index, initial);
+        self.switch_to(initial);
+        panic!("This code should not run");
+    }
+
+    pub unsafe fn switch(&mut self) {
+        intrin::disable_irq();
+
+        let mut queue = self.queue.lock();
+
+        let src = queue.current;
+        assert!(!src.is_null());
+        let src = &mut *src;
+
+        let dst = if !src.queue_next.is_null() {
+            src.queue_next
+        } else if !queue.head.is_null() {
+            queue.head
+        } else {
+            self.idle.as_mut_ptr()
+        };
+
+        assert!(!dst.is_null());
+        //debugln!("cpu{}: {:p} -> {:p}", self.cpu_index, src, dst);
+        drop(queue);
+
+        self.switch_to(dst);
+    }
+
+    pub unsafe fn get() -> &'static mut Self {
+        &mut SCHEDULER
+    }
+}
+
+unsafe impl Send for Queue {}
+
+extern "C" fn idle_fn(_arg: usize) {
+    loop {}
+}
+
+static mut SCHEDULER: Scheduler = Scheduler::new();
+
+pub fn queue(proc: *mut Process) {
+    unsafe {
+        Scheduler::get().queue(proc);
+    }
+}
+
+pub fn sched_yield() {
+    unsafe {
+        let mut sched = Scheduler::get();
+        if sched.is_ready() {
+            sched.switch();
+        }
+    }
+}
+
+pub fn unqueue(proc: *mut Process) {
+    todo!()
+}

kernel/src/sync.rs

@@ -0,0 +1,78 @@
+use crate::arch::{intrin, cpu::{self, Cpu}};
+use core::cell::UnsafeCell;
+use core::ops::{Deref, DerefMut};
+use core::sync::atomic::{AtomicUsize, Ordering};
+
+pub struct Spin<T: ?Sized + Send> {
+    inner: AtomicUsize,
+    value: UnsafeCell<T>,
+}
+
+pub struct SpinGuard<'a, T: ?Sized + Send> {
+    inner: &'a AtomicUsize,
+    value: &'a mut T,
+    irq_state: usize,
+}
+
+impl<T: Send> Spin<T> {
+    #[inline(always)]
+    pub const fn new(value: T) -> Self {
+        Self {
+            inner: AtomicUsize::new(usize::MAX),
+            value: UnsafeCell::new(value),
+        }
+    }
+}
+
+impl<T: ?Sized + Send> Spin<T> {
+    #[inline]
+    pub fn lock(&self) -> SpinGuard<T> {
+        let irq_state = unsafe { intrin::save_irq() };
+        let cpu_id = cpu::get_phys_id();
+
+        while self
+            .inner
+            .compare_exchange_weak(usize::MAX, cpu_id as usize, Ordering::Acquire, Ordering::Relaxed)
+            .is_err()
+        {
+            while self.inner.load(Ordering::Relaxed) != usize::MAX {
+                intrin::nop();
+            }
+        }
+
+        SpinGuard {
+            inner: &self.inner,
+            value: unsafe { &mut *self.value.get() },
+            irq_state,
+        }
+    }
+}
+
+unsafe impl<T: ?Sized + Send> Sync for Spin<T> {}
+unsafe impl<T: ?Sized + Send> Send for Spin<T> {}
+
+impl<'a, T: ?Sized + Send> Drop for SpinGuard<'a, T> {
+    #[inline]
+    fn drop(&mut self) {
+        self.inner.store(usize::MAX, Ordering::Release);
+        unsafe {
+            intrin::restore_irq(self.irq_state);
+        }
+    }
+}
+
+impl<'a, T: ?Sized + Send> Deref for SpinGuard<'a, T> {
+    type Target = T;
+
+    #[inline(always)]
+    fn deref(&self) -> &Self::Target {
+        self.value
+    }
+}
+
+impl<'a, T: ?Sized + Send> DerefMut for SpinGuard<'a, T> {
+    #[inline(always)]
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        self.value
+    }
+}

qemu.sh

@@ -6,14 +6,18 @@ if [ -z "${MACH}" ]; then
     MACH=rpi3b
 fi
 
+if [ -z "${PROFILE}" ]; then
+    PROFILE=debug
+fi
+
 if [ -z "$QEMU_BIN" ]; then
     QEMU_BIN=qemu-system-aarch64
 fi
 
 ARCH=aarch64-unknown-none-${MACH}
-KERNEL=target/${ARCH}/debug/kernel
+KERNEL=target/${ARCH}/${PROFILE}/kernel
 
-QEMU_OPTS="-chardev stdio,nowait,id=char0,mux=on \
+QEMU_OPTS="-chardev stdio,wait=off,id=char0,mux=on \
            -mon chardev=char0"
 
 if [ "$QEMU_DINT" = 1 ]; then
@@ -39,6 +43,7 @@ esac
 QEMU_OPTS="$QEMU_OPTS \
            -kernel ${KERNEL} \
            -display none \
+           -device rtl8139 \
            -s"
 
 ./build.sh