feat(kernel): add RequestPages and ReleasePages syscalls

crates/kernel/src/tests/memory.rs

@@ -0,0 +1,49 @@
+use super::*;
+use crate::{SyscallOutcome, SyscallResult};
+use domain::syscall::Syscall;
+use types::bounded::PageCount;
+use types::address::VirtualAddress;
+
+#[test]
+fn request_pages_allocates_and_grants_cap() {
+    let (mut k, _) = kernel_with_process();
+    let outcome = k.handle_syscall(Syscall::RequestPages {
+        count: PageCount::new(4).unwrap(),
+    });
+    assert!(matches!(
+        outcome,
+        SyscallOutcome::Complete(SyscallResult::Slot(_))
+    ));
+}
+
+#[test]
+fn request_pages_reduces_pool() {
+    let (mut k, _) = kernel_with_process();
+    let before = k.free_page_count();
+    k.handle_syscall(Syscall::RequestPages {
+        count: PageCount::new(10).unwrap(),
+    });
+    assert_eq!(k.free_page_count(), before - 10);
+}
+
+#[test]
+fn release_pages_frees_and_restores_pool() {
+    let (mut k, _) = kernel_with_process();
+    let before = k.free_page_count();
+    let slot = match k.handle_syscall(Syscall::RequestPages {
+        count: PageCount::new(4).unwrap(),
+    }) {
+        SyscallOutcome::Complete(SyscallResult::Slot(s)) => s,
+        _ => panic!("expected slot"),
+    };
+
+    let outcome = k.handle_syscall(Syscall::ReleasePages {
+        addr: VirtualAddress::from_raw(0x8000_0000),
+        count: PageCount::new(4).unwrap(),
+    });
+    assert!(matches!(
+        outcome,
+        SyscallOutcome::Complete(SyscallResult::Ok)
+    ));
+    assert_eq!(k.free_page_count(), before);
+}