Remove the shim kernel crate

kernel/src/syscall/brk.rs

@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: MPL-2.0
+
+use crate::{prelude::*, syscall::SyscallReturn};
+
+/// expand the user heap to new heap end, returns the new heap end if expansion succeeds.
+pub fn sys_brk(heap_end: u64, ctx: &Context) -> Result<SyscallReturn> {
+    let new_heap_end = if heap_end == 0 {
+        None
+    } else {
+        Some(heap_end as usize)
+    };
+    debug!("new heap end = {:x?}", heap_end);
+    let user_heap = ctx.process.heap();
+    let new_heap_end = user_heap.brk(new_heap_end)?;
+
+    Ok(SyscallReturn::Return(new_heap_end as _))
+}