feat(kernel): console cap gates DebugPutchar, no uart fast path; spawn start arg in a0; delegate returns slot

crates/libkos/src/syscall/caps.rs

@@ -8,8 +8,9 @@ use types::syscall_abi::*;
 
 // ---- capabilities ----
 
-pub fn delegate(slot: CapSlot, to: CapSlot, permissions: PermissionSet) -> bool {
-    raw(
+/// Returns the slot the copy landed in, in `to`'s table.
+pub fn delegate(slot: CapSlot, to: CapSlot, permissions: PermissionSet) -> Option<CapSlot> {
+    slot_of(raw(
         SYS_DELEGATE,
         [
             slot.value() as usize,
@@ -19,8 +20,8 @@ pub fn delegate(slot: CapSlot, to: CapSlot, permissions: PermissionSet) -> bool
             0,
             0,
         ],
-    )
-    .is_ok()
+    ))
+    .ok()
 }
 
 /// Copies an unbadged endpoint or notification capability with `badge`

crates/libkos/src/syscall/process.rs

@@ -46,18 +46,19 @@ pub fn create_process(create_cap: CapSlot) -> Option<CapSlot> {
     .ok()
 }
 
-pub fn spawn_thread(entry: EntryPoint, stack: StackPointer) -> usize {
-    raw(SYS_SPAWN_THREAD, [entry.raw(), stack.raw(), 0, 0, 0, 0]).map_or(NONE, |r| r[1])
+/// `arg` arrives in the new thread's `a0` (see `libkos::start`).
+pub fn spawn_thread(entry: EntryPoint, stack: StackPointer, arg: usize) -> usize {
+    raw(SYS_SPAWN_THREAD, [entry.raw(), stack.raw(), arg, 0, 0, 0]).map_or(NONE, |r| r[1])
 }
 
-pub fn spawn_thread_in(process_cap: CapSlot, entry: EntryPoint, stack: StackPointer) -> usize {
+pub fn spawn_thread_in(process_cap: CapSlot, entry: EntryPoint, stack: StackPointer, arg: usize) -> usize {
     raw(
         SYS_SPAWN_THREAD_IN,
         [
             process_cap.value() as usize,
             entry.raw(),
             stack.raw(),
-            0,
+            arg,
             0,
             0,
         ],
@@ -69,6 +70,6 @@ pub fn kill(process_cap: CapSlot) -> bool {
     raw(SYS_KILL, [process_cap.value() as usize, 0, 0, 0, 0, 0]).is_ok()
 }
 
-pub fn debug_putchar(byte: u8) {
-    let _ = raw(SYS_DEBUG_PUTCHAR, [byte as usize, 0, 0, 0, 0, 0]);
+pub fn debug_putchar(console: CapSlot, byte: u8) {
+    let _ = raw(SYS_DEBUG_PUTCHAR, [console.value() as usize, byte as usize, 0, 0, 0, 0]);
 }