feat: create libkos crate with core modules (syscall, alloc, rt)

Cargo.toml

@@ -53,6 +53,7 @@ members = [
     "crates/drivers/input/uart",
     "crates/drivers/input/virtio",
     "crates/hw-virtio",
+    "crates/libkos",
 ]
 resolver = "2"
 
@@ -99,6 +100,9 @@ user-manager = { path = "crates/servers/user-manager" }
 # hw
 hw-virtio = { path = "crates/hw-virtio" }
 
+# libkos
+libkos = { path = "crates/libkos" }
+
 # ports
 port-framebuffer = { path = "crates/ports/framebuffer" }
 port-block-device = { path = "crates/ports/block-device" }

crates/libkos/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "libkos"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+types = { workspace = true }

crates/libkos/src/alloc_impl.rs

@@ -0,0 +1,141 @@
+use core::alloc::{GlobalAlloc, Layout};
+use core::cell::UnsafeCell;
+use core::ptr;
+
+const PAGE_SIZE: usize = 4096;
+const MAX_PAGES: usize = 64;
+
+struct FreeBlock {
+    size: usize,
+    next: *mut FreeBlock,
+}
+
+pub struct KosAllocator {
+    inner: UnsafeCell<AllocatorInner>,
+}
+
+struct AllocatorInner {
+    free_list: *mut FreeBlock,
+    pages: [usize; MAX_PAGES],
+    page_count: usize,
+}
+
+unsafe impl Sync for KosAllocator {}
+
+impl KosAllocator {
+    pub const fn new() -> Self {
+        Self {
+            inner: UnsafeCell::new(AllocatorInner {
+                free_list: ptr::null_mut(),
+                pages: [0; MAX_PAGES],
+                page_count: 0,
+            }),
+        }
+    }
+
+    fn inner_mut(&self) -> &mut AllocatorInner {
+        unsafe { &mut *self.inner.get() }
+    }
+}
+
+impl AllocatorInner {
+    fn request_page(&mut self) -> *mut u8 {
+        if self.page_count >= MAX_PAGES {
+            return ptr::null_mut();
+        }
+
+        let count = match types::bounded::PageCount::new(1) {
+            Some(c) => c,
+            None => return ptr::null_mut(),
+        };
+        let va = match crate::syscall::request_pages(count) {
+            Some(va) => va,
+            None => return ptr::null_mut(),
+        };
+
+        self.pages[self.page_count] = va.raw();
+        self.page_count += 1;
+        va.raw() as *mut u8
+    }
+
+    fn alloc_from_free_list(&mut self, size: usize, align: usize) -> *mut u8 {
+        let mut prev: *mut FreeBlock = ptr::null_mut();
+        let mut current = self.free_list;
+
+        while !current.is_null() {
+            let block = unsafe { &mut *current };
+            let addr = current as usize;
+            let aligned = (addr + align - 1) & !(align - 1);
+            let padding = aligned - addr;
+
+            if block.size >= size + padding {
+                let remaining = block.size - size - padding;
+
+                if remaining >= core::mem::size_of::<FreeBlock>() {
+                    let new_block = (aligned + size) as *mut FreeBlock;
+                    unsafe {
+                        (*new_block).size = remaining;
+                        (*new_block).next = block.next;
+                    }
+                    if prev.is_null() {
+                        self.free_list = new_block;
+                    } else {
+                        unsafe { (*prev).next = new_block; }
+                    }
+                } else {
+                    if prev.is_null() {
+                        self.free_list = block.next;
+                    } else {
+                        unsafe { (*prev).next = block.next; }
+                    }
+                }
+
+                return aligned as *mut u8;
+            }
+
+            prev = current;
+            current = block.next;
+        }
+
+        ptr::null_mut()
+    }
+
+    fn add_to_free_list(&mut self, ptr: *mut u8, size: usize) {
+        let block = ptr as *mut FreeBlock;
+        unsafe {
+            (*block).size = size;
+            (*block).next = self.free_list;
+        }
+        self.free_list = block;
+    }
+}
+
+unsafe impl GlobalAlloc for KosAllocator {
+    unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
+        let inner = self.inner_mut();
+        let size = layout.size().max(core::mem::size_of::<FreeBlock>());
+        let align = layout.align();
+
+        let ptr = inner.alloc_from_free_list(size, align);
+        if !ptr.is_null() {
+            return ptr;
+        }
+
+        let pages_needed = (size + PAGE_SIZE - 1) / PAGE_SIZE;
+        for _ in 0..pages_needed {
+            let page = inner.request_page();
+            if page.is_null() {
+                return ptr::null_mut();
+            }
+            inner.add_to_free_list(page, PAGE_SIZE);
+        }
+
+        inner.alloc_from_free_list(size, align)
+    }
+
+    unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
+        let inner = self.inner_mut();
+        let size = layout.size().max(core::mem::size_of::<FreeBlock>());
+        inner.add_to_free_list(ptr, size);
+    }
+}

crates/libkos/src/arch/mock.rs

@@ -0,0 +1,27 @@
+pub fn syscall0(_nr: usize) -> usize {
+    0
+}
+
+pub fn syscall1(_nr: usize, _a0: usize) -> usize {
+    0
+}
+
+pub fn syscall2(_nr: usize, _a0: usize, _a1: usize) -> usize {
+    0
+}
+
+pub fn syscall3(_nr: usize, _a0: usize, _a1: usize, _a2: usize) -> usize {
+    0
+}
+
+pub fn syscall4(_nr: usize, _a0: usize, _a1: usize, _a2: usize, _a3: usize) -> usize {
+    0
+}
+
+pub fn syscall5(_nr: usize, _a0: usize, _a1: usize, _a2: usize, _a3: usize, _a4: usize) -> usize {
+    0
+}
+
+pub fn syscall_receive(_nr: usize, _a0: usize) -> (usize, usize, usize, usize) {
+    (0, 0, 0, 0)
+}

crates/libkos/src/arch/mod.rs

@@ -0,0 +1,9 @@
+#[cfg(all(target_arch = "riscv64", target_os = "none"))]
+mod riscv;
+#[cfg(all(target_arch = "riscv64", target_os = "none"))]
+pub use riscv::*;
+
+#[cfg(not(target_os = "none"))]
+mod mock;
+#[cfg(not(target_os = "none"))]
+pub use mock::*;

crates/libkos/src/arch/riscv.rs

@@ -0,0 +1,106 @@
+#[inline(always)]
+pub fn syscall0(nr: usize) -> usize {
+    let ret: usize;
+    unsafe {
+        core::arch::asm!(
+            "ecall",
+            in("a7") nr,
+            lateout("a0") ret,
+        );
+    }
+    ret
+}
+
+#[inline(always)]
+pub fn syscall1(nr: usize, a0: usize) -> usize {
+    let ret: usize;
+    unsafe {
+        core::arch::asm!(
+            "ecall",
+            in("a7") nr,
+            inlateout("a0") a0 => ret,
+        );
+    }
+    ret
+}
+
+#[inline(always)]
+pub fn syscall2(nr: usize, a0: usize, a1: usize) -> usize {
+    let ret: usize;
+    unsafe {
+        core::arch::asm!(
+            "ecall",
+            in("a7") nr,
+            inlateout("a0") a0 => ret,
+            in("a1") a1,
+        );
+    }
+    ret
+}
+
+#[inline(always)]
+pub fn syscall3(nr: usize, a0: usize, a1: usize, a2: usize) -> usize {
+    let ret: usize;
+    unsafe {
+        core::arch::asm!(
+            "ecall",
+            in("a7") nr,
+            inlateout("a0") a0 => ret,
+            in("a1") a1,
+            in("a2") a2,
+        );
+    }
+    ret
+}
+
+#[inline(always)]
+pub fn syscall4(nr: usize, a0: usize, a1: usize, a2: usize, a3: usize) -> usize {
+    let ret: usize;
+    unsafe {
+        core::arch::asm!(
+            "ecall",
+            in("a7") nr,
+            inlateout("a0") a0 => ret,
+            in("a1") a1,
+            in("a2") a2,
+            in("a3") a3,
+        );
+    }
+    ret
+}
+
+#[inline(always)]
+pub fn syscall5(nr: usize, a0: usize, a1: usize, a2: usize, a3: usize, a4: usize) -> usize {
+    let ret: usize;
+    unsafe {
+        core::arch::asm!(
+            "ecall",
+            in("a7") nr,
+            inlateout("a0") a0 => ret,
+            in("a1") a1,
+            in("a2") a2,
+            in("a3") a3,
+            in("a4") a4,
+        );
+    }
+    ret
+}
+
+#[inline(always)]
+pub fn syscall_receive(nr: usize, a0: usize) -> (usize, usize, usize, usize) {
+    let r0: usize;
+    let r1: usize;
+    let r2: usize;
+    let r3: usize;
+    unsafe {
+        core::arch::asm!(
+            "ecall",
+            in("a7") nr,
+            inlateout("a0") a0 => r0,
+            lateout("a1") r1,
+            lateout("a2") r2,
+            lateout("a3") r3,
+        );
+    }
+    (r0, r1, r2, r3)
+}

crates/libkos/src/lib.rs

@@ -0,0 +1,12 @@
+#![no_std]
+
+extern crate alloc;
+
+mod arch;
+pub mod syscall;
+pub mod alloc_impl;
+mod rt;
+
+#[cfg(target_os = "none")]
+#[global_allocator]
+static ALLOCATOR: alloc_impl::KosAllocator = alloc_impl::KosAllocator::new();

crates/libkos/src/rt.rs

@@ -0,0 +1,21 @@
+// Architecture-specific entry points.
+// To add a new architecture: add a cfg block with the appropriate global_asm.
+
+#[cfg(all(target_arch = "riscv64", target_os = "none"))]
+core::arch::global_asm!(
+    r#"
+.section .text.entry
+.globl _start
+_start:
+    call main
+    li a7, 16
+    ecall
+    j _start
+"#
+);
+
+#[cfg(target_os = "none")]
+#[panic_handler]
+fn panic(_: &core::panic::PanicInfo) -> ! {
+    crate::syscall::exit();
+}

crates/libkos/src/syscall.rs

@@ -0,0 +1,85 @@
+use crate::arch;
+use types::syscall_abi::*;
+use types::address::{EntryPoint, StackPointer, VirtualAddress};
+use types::bounded::{CapSlot, PageCount};
+use types::id::ProcessId;
+use types::permission::PermissionSet;
+use types::time::Ticks;
+
+pub fn exit() -> ! {
+    arch::syscall0(SYS_EXIT);
+    loop {}
+}
+
+pub fn exit_thread() -> ! {
+    arch::syscall0(SYS_EXIT_THREAD);
+    loop {}
+}
+
+pub fn yield_now() {
+    arch::syscall0(SYS_YIELD);
+}
+
+pub fn halt() -> ! {
+    arch::syscall0(SYS_HALT);
+    loop {}
+}
+
+pub fn get_time() -> Ticks {
+    Ticks::from_raw(arch::syscall0(SYS_GET_TIME) as u64)
+}
+
+pub fn get_process_id() -> ProcessId {
+    ProcessId::from_raw(arch::syscall0(SYS_GET_PROCESS_ID) as u16)
+}
+
+pub fn create_process(create_cap: CapSlot) -> Option<CapSlot> {
+    let r = arch::syscall1(SYS_CREATE_PROCESS, create_cap.value() as usize);
+    if r == usize::MAX { None } else { CapSlot::new(r as u8) }
+}
+
+pub fn create_endpoint() -> Option<CapSlot> {
+    let r = arch::syscall0(SYS_CREATE_ENDPOINT);
+    if r == usize::MAX { None } else { CapSlot::new(r as u8) }
+}
+
+pub fn spawn_thread(entry: EntryPoint, stack: StackPointer) -> usize {
+    arch::syscall2(SYS_SPAWN_THREAD, entry.raw(), stack.raw())
+}
+
+pub fn spawn_thread_in(process_cap: CapSlot, entry: EntryPoint, stack: StackPointer) -> usize {
+    arch::syscall3(SYS_SPAWN_THREAD_IN, process_cap.value() as usize, entry.raw(), stack.raw())
+}
+
+pub fn request_pages(count: PageCount) -> Option<VirtualAddress> {
+    let r = arch::syscall1(SYS_REQUEST_PAGES, count.value() as usize);
+    if r == usize::MAX { None } else { Some(VirtualAddress::from_raw(r)) }
+}
+
+pub fn map_page(process_cap: CapSlot, src_va: VirtualAddress, dst_va: VirtualAddress, executable: bool) -> bool {
+    arch::syscall4(SYS_MAP_PAGE, process_cap.value() as usize, src_va.raw(), dst_va.raw(), executable as usize) == 0
+}
+
+pub fn send(endpoint: CapSlot, w0: usize, w1: usize, w2: usize, w3: usize) -> usize {
+    arch::syscall5(SYS_SEND, endpoint.value() as usize, w0, w1, w2, w3)
+}
+
+pub fn receive(endpoint: CapSlot) -> (usize, usize, usize, usize) {
+    arch::syscall_receive(SYS_RECEIVE, endpoint.value() as usize)
+}
+
+pub fn delegate(slot: CapSlot, to: CapSlot, permissions: PermissionSet) -> bool {
+    arch::syscall3(SYS_DELEGATE, slot.value() as usize, to.value() as usize, permissions.bits() as usize) == 0
+}
+
+pub fn kill(process_cap: CapSlot) -> bool {
+    arch::syscall1(SYS_KILL, process_cap.value() as usize) == 0
+}
+
+pub fn revoke(slot: CapSlot) -> bool {
+    arch::syscall1(SYS_REVOKE, slot.value() as usize) == 0
+}
+
+pub fn debug_putchar(byte: u8) {
+    arch::syscall1(SYS_DEBUG_PUTCHAR, byte as usize);
+}