feat: userspace program loading and task spawning

userspace/dusk-sys/src/lib.rs

@@ -12,6 +12,14 @@ pub enum Status {
     OutOfMemory = 5,
 }
 
+// Opaque handle type
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub struct Handle(usize);
+
+// our own address space and thread handle are always given to us
+pub const SELF_AS: Handle = Handle(0);
+pub const SELF_THREAD: Handle = Handle(1);
+
 impl From<usize> for Status {
     fn from(value: usize) -> Self {
         match value {
@@ -25,6 +33,21 @@ impl From<usize> for Status {
     }
 }
 
+#[repr(u64)]
+pub enum SyscallNumber {
+    Yield = 1,
+    Exit = 2,
+    Write = 3,
+    Send = 4,
+    Recv = 5,
+    FrameAlloc = 6,
+    FrameDealloc = 7,
+    AsCreate = 8,
+    Map = 9,
+    Unmap = 10,
+    TaskCreate = 11,
+}
+
 pub fn sys_yield() {
     unsafe {
         asm!(
@@ -46,7 +69,7 @@ fn debug_write(buf: &str) -> Result<(), Status> {
             in("rsi") buf.as_ptr(),
             in("rdx") buf.len(),
             in("r10") 0,
-            inlateout("rax") 3usize => status,
+            inlateout("rax") SyscallNumber::Write as usize => status,
             lateout("rcx") _,
             lateout("r11") _
         );
@@ -96,7 +119,7 @@ pub fn sys_exit(exit_code: usize) -> ! {
         asm!(
             "syscall",
             in("rdi") exit_code,
-            in("rax") 2usize,
+            in("rax") SyscallNumber::Exit as usize,
             options(noreturn)
         );
     }
@@ -111,7 +134,7 @@ pub fn sys_send(dest_task_id: usize, msg_ptr: usize, len: usize) -> Result<(), S
             in("rdi") dest_task_id,
             in("rsi") msg_ptr,
             in("rdx") len,
-            inlateout("rax") 4usize => status,
+            inlateout("rax") SyscallNumber::Send as usize => status,
             lateout("rcx") _,
             lateout("r11") _,
         );
@@ -137,7 +160,7 @@ pub fn sys_recv(buf_ptr: usize, max_len: usize) -> Result<(usize, usize), Status
             in("rsi") max_len,
             in("rdx") &raw mut actual_len as usize,
             in("r10") &raw mut sender as usize,
-            inlateout("rax") 5usize => status,
+            inlateout("rax") SyscallNumber::Recv as usize => status,
             lateout("rcx") _,
             lateout("r11") _,
         );
@@ -149,3 +172,143 @@ pub fn sys_recv(buf_ptr: usize, max_len: usize) -> Result<(usize, usize), Status
         }
     }
 }
+
+pub fn sys_frame_alloc() -> Result<Handle, Status> {
+    let mut handle: usize = 0;
+    unsafe {
+        let status: usize;
+
+        asm!(
+            "syscall",
+            in("rdi") &raw mut handle as usize,
+            inlateout("rax") SyscallNumber::FrameAlloc as usize => status,
+            lateout("rcx") _,
+            lateout("r11") _,
+        );
+
+        if status != 0 {
+            Err(status.into())
+        } else {
+            Ok(Handle(handle))
+        }
+    }
+}
+
+pub fn sys_frame_dealloc(frame_handle: Handle) -> Result<(), Status> {
+    unsafe {
+        let status: usize;
+
+        asm!(
+            "syscall",
+            in("rdi") frame_handle.0,
+            inlateout("rax") SyscallNumber::FrameDealloc as usize => status,
+            lateout("rcx") _,
+            lateout("r11") _,
+        );
+
+        if status != 0 {
+            Err(status.into())
+        } else {
+            Ok(())
+        }
+    }
+}
+
+pub fn sys_as_create() -> Result<Handle, Status> {
+    let mut handle: usize = 0;
+    unsafe {
+        let status: usize;
+
+        asm!(
+            "syscall",
+            in("rdi") &raw mut handle as usize,
+            inlateout("rax") SyscallNumber::AsCreate as usize => status,
+            lateout("rcx") _,
+            lateout("r11") _,
+        );
+
+        if status != 0 {
+            Err(status.into())
+        } else {
+            Ok(Handle(handle))
+        }
+    }
+}
+
+pub fn sys_map(
+    as_handle: Handle,
+    frame_handle: Handle,
+    virtual_addr: usize,
+    permissions: usize,
+) -> Result<(), Status> {
+    unsafe {
+        let status: usize;
+
+        asm!(
+            "syscall",
+            in("rdi") as_handle.0,
+            in("rsi") frame_handle.0,
+            in("rdx") virtual_addr,
+            in("r10") permissions,
+            inlateout("rax") SyscallNumber::Map as usize => status,
+            lateout("rcx") _,
+            lateout("r11") _,
+        );
+
+        if status != 0 {
+            Err(status.into())
+        } else {
+            Ok(())
+        }
+    }
+}
+
+pub fn sys_unmap(as_handle: Handle, virtual_addr: usize) -> Result<(), Status> {
+    unsafe {
+        let status: usize;
+
+        asm!(
+            "syscall",
+            in("rdi") as_handle.0,
+            in("rsi") virtual_addr,
+            inlateout("rax") SyscallNumber::Unmap as usize => status,
+            lateout("rcx") _,
+            lateout("r11") _,
+        );
+
+        if status != 0 {
+            Err(status.into())
+        } else {
+            Ok(())
+        }
+    }
+}
+
+pub fn sys_task_create(
+    as_handle: Handle,
+    entry: usize,
+    user_stack: usize,
+) -> Result<Handle, Status> {
+    let mut handle: usize = 0;
+
+    unsafe {
+        let status: usize;
+
+        asm!(
+            "syscall",
+            in("rdi") as_handle.0,
+            in("rsi") entry,
+            in("rdx") user_stack,
+            in("r10") &raw mut handle as usize,
+            inlateout("rax") SyscallNumber::TaskCreate as usize => status,
+            lateout("rcx") _,
+            lateout("r11") _,
+        );
+
+        if status != 0 {
+            Err(status.into())
+        } else {
+            Ok(Handle(handle))
+        }
+    }
+}