From dcadb8308869740a5c1d89181522533a4f670d37 Mon Sep 17 00:00:00 2001
From: Gabriel Kaszewski <gabrielkaszewski@gmail.com>
Date: Sun, 18 Oct 2026 01:30:23 +0200
Subject: [PATCH] feat: add Platform::map_shared and wire memory delegation to
 page mapping

---
 crates/kernel/src/syscall/capability.rs  | 18 +++++++++++++++---
 crates/kernel/src/tests/mock_platform.rs | 12 +++++++++++-
 crates/platform/src/lib.rs               | 11 ++++++++++-
 3 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/crates/kernel/src/syscall/capability.rs b/crates/kernel/src/syscall/capability.rs
index 3a7e9cd..0db8596 100644
--- a/crates/kernel/src/syscall/capability.rs
+++ b/crates/kernel/src/syscall/capability.rs
@@ -39,10 +39,22 @@ impl<P: Platform> Kernel<P> {
             Err(e) => return SyscallOutcome::Complete(SyscallResult::Error(e)),
         };
 
-        match self.grant_cap(target_pid, resource, restricted) {
-            Ok(_) => SyscallOutcome::Complete(SyscallResult::Ok),
-            Err(e) => SyscallOutcome::Complete(SyscallResult::Error(e)),
+        if let Err(e) = self.grant_cap(target_pid, resource.clone(), restricted) {
+            return SyscallOutcome::Complete(SyscallResult::Error(e));
         }
+
+        if let domain::resource::Resource::Memory(region_id) = &resource {
+            if let Some(region) = self.regions.get(*region_id) {
+                self.platform.map_shared(
+                    target_pid,
+                    region.base(),
+                    region.size(),
+                    restricted,
+                );
+            }
+        }
+
+        SyscallOutcome::Complete(SyscallResult::Ok)
     }
 
     pub(crate) fn handle_revoke(
diff --git a/crates/kernel/src/tests/mock_platform.rs b/crates/kernel/src/tests/mock_platform.rs
index 8ef02d9..d92bd4d 100644
--- a/crates/kernel/src/tests/mock_platform.rs
+++ b/crates/kernel/src/tests/mock_platform.rs
@@ -2,8 +2,10 @@ use domain::memory::MemoryRegion;
 use domain::thread::SavedContext;
 use platform::Platform;
 use types::{
-    address::{EntryPoint, StackPointer},
+    address::{EntryPoint, PhysicalAddress, StackPointer},
+    bounded::PageCount,
     id::{CoreId, IrqId, ProcessId},
+    permission::PermissionSet,
     time::{Ticks, TimerDuration},
 };
 
@@ -46,4 +48,12 @@ impl Platform for MockPlatform {
     fn num_cores(&self) -> u8 {
         self.cores
     }
+    fn map_shared(
+        &mut self,
+        _process: ProcessId,
+        _base: PhysicalAddress,
+        _size: PageCount,
+        _permissions: PermissionSet,
+    ) {
+    }
 }
diff --git a/crates/platform/src/lib.rs b/crates/platform/src/lib.rs
index 61f0091..bf65a0c 100644
--- a/crates/platform/src/lib.rs
+++ b/crates/platform/src/lib.rs
@@ -2,8 +2,10 @@
 
 use domain::{memory::MemoryRegion, thread::SavedContext};
 use types::{
-    address::{EntryPoint, StackPointer},
+    address::{EntryPoint, PhysicalAddress, StackPointer},
+    bounded::PageCount,
     id::{CoreId, IrqId, ProcessId},
+    permission::PermissionSet,
     time::{Ticks, TimerDuration},
 };
 
@@ -20,4 +22,11 @@ pub trait Platform {
     fn send_ipi(&mut self, target: CoreId);
     fn core_id(&self) -> CoreId;
     fn num_cores(&self) -> u8;
+    fn map_shared(
+        &mut self,
+        process: ProcessId,
+        base: PhysicalAddress,
+        size: PageCount,
+        permissions: PermissionSet,
+    );
 }