[Zion] Add a AddressSpaceUnmap syscall to free memory.

lib/glacier/container/binary_tree.h

@@ -74,32 +74,32 @@ void BinaryTree<K, V>::Delete(K key) {
   }
 
   RefPtr<BinaryNode> new_child = nullptr;
-  if (!node.left) {
+  if (!node->left) {
     // No children.
     // Right child only.
-    new_child = node.right;
-  } else if (!node.right) {
+    new_child = node->right;
+  } else if (!node->right) {
     // Left child only.
-    new_child = node.left;
+    new_child = node->left;
   } else {
     // Find Successor.
-    auto successor = node.right;
-    while (successor.left) {
-      successor = successor.left;
+    auto successor = node->right;
+    while (successor->left) {
+      successor = successor->left;
     }
     new_child = successor;
-    if (successor != node.right) {
-      successor.parent.left = successor.right;
+    if (successor != node->right) {
+      successor->parent->left = successor->right;
     }
   }
 
   if (node == root_) {
     root_ = new_child;
   } else {
-    if (node.parent.right == node) {
-      node.parent.right = new_child;
+    if (node->parent->right == node) {
+      node->parent->right = new_child;
     } else {
-      node.parent.left = new_child;
+      node->parent->left = new_child;
     }
   }
 }

zion/CMakeLists.txt

@@ -11,6 +11,7 @@ add_executable(zion
   interrupt/interrupt.cpp
   interrupt/interrupt_enter.s
   interrupt/timer.cpp
+  lib/memory_mapping_tree.cpp
   lib/message_queue.cpp
   loader/init_loader.cpp
   memory/kernel_heap.cpp

zion/include/zcall.h

@@ -19,6 +19,8 @@ SYS1(ThreadWait, z_cap_t, thread_cap);
 
 SYS4(AddressSpaceMap, z_cap_t, vmas_cap, uint64_t, vmas_offset, z_cap_t,
      vmmo_cap, uint64_t*, vaddr);
+SYS3(AddressSpaceUnmap, z_cap_t, vmas_cap, uint64_t, lower_addr, uint64_t,
+     upper_addr);
 
 SYS2(MemoryObjectCreate, uint64_t, size, z_cap_t*, vmmo_cap);
 SYS3(MemoryObjectCreatePhysical, uint64_t, paddr, uint64_t, size, z_cap_t*,

zion/include/ztypes.h

@@ -21,7 +21,7 @@ const uint64_t kZionThreadWait = 0x13;
 
 // Memory Calls
 const uint64_t kZionAddressSpaceMap = 0x21;
-const uint64_t kZionAddressSpaceUnMap = 0x21;
+const uint64_t kZionAddressSpaceUnmap = 0x22;
 
 const uint64_t kZionMemoryObjectCreate = 0x30;
 const uint64_t kZionMemoryObjectCreatePhysical = 0x31;

zion/lib/memory_mapping_tree.cpp

@@ -28,9 +28,32 @@ glcr::ErrorCode MemoryMappingTree::AddInMemoryObject(
   return glcr::OK;
 }
 
-glcr::ErrorCode FreeMemoryRange(uint64_t vaddr_base, uint64_t vaddr_limit) {
-  dbgln("Unhandled free memory range!");
-  return glcr::OK;
+glcr::ErrorCode MemoryMappingTree::FreeMemoryRange(uint64_t vaddr_base,
+                                                   uint64_t vaddr_limit) {
+  if (vaddr_limit <= vaddr_base) {
+    return glcr::INVALID_ARGUMENT;
+  }
+  auto predecessor_or = mapping_tree_.Predecessor(vaddr_base);
+  if (predecessor_or && predecessor_or.value().get().vaddr_limit > vaddr_base) {
+    return glcr::FAILED_PRECONDITION;
+  }
+  auto last_predecessor_or = mapping_tree_.Predecessor(vaddr_limit);
+  if (last_predecessor_or &&
+      last_predecessor_or.value().get().vaddr_limit > vaddr_limit) {
+    return glcr::FAILED_PRECONDITION;
+  }
+
+  auto find_or = mapping_tree_.Find(vaddr_base);
+  if (find_or) {
+    mapping_tree_.Delete(vaddr_base);
+  }
+  while (true) {
+    auto successor_or = mapping_tree_.Successor(vaddr_base);
+    if (!successor_or || successor_or.value().get().vaddr_base >= vaddr_limit) {
+      return glcr::OK;
+    }
+    mapping_tree_.Delete(successor_or.value().get().vaddr_base);
+  }
 }
 
 glcr::ErrorOr<uint64_t> MemoryMappingTree::GetPhysicalPageAtVaddr(

zion/object/address_space.h

@@ -76,6 +76,11 @@ class AddressSpace : public KernelObject {
   [[nodiscard]] glcr::ErrorOr<uint64_t> MapInMemoryObject(
       const glcr::RefPtr<MemoryObject>& mem_obj);
 
+  [[nodiscard]] glcr::ErrorCode FreeAddressRange(uint64_t vaddr_base,
+                                                 uint64_t vaddr_limit) {
+    return mapping_tree_.FreeMemoryRange(vaddr_base, vaddr_limit);
+  }
+
   // Kernel Mappings.
   uint64_t AllocateKernelStack();
 

zion/syscall/address_space.cpp

@@ -15,10 +15,19 @@ z_err_t AddressSpaceMap(ZAddressSpaceMapReq* req) {
 
   // FIXME: Validation necessary.
   if (req->vmas_offset != 0) {
-    vmas->MapInMemoryObject(req->vmas_offset, vmmo);
+    RET_ERR(vmas->MapInMemoryObject(req->vmas_offset, vmmo));
     *req->vaddr = req->vmas_offset;
   } else {
-    *req->vaddr = vmas->MapInMemoryObject(vmmo);
+    ASSIGN_OR_RETURN(*req->vaddr, vmas->MapInMemoryObject(vmmo));
   }
   return glcr::OK;
 }
+
+z_err_t AddressSpaceUnmap(ZAddressSpaceUnmapReq* req) {
+  auto& curr_proc = gScheduler->CurrentProcess();
+  auto vmas_cap = curr_proc.GetCapability(req->vmas_cap);
+  RET_ERR(ValidateCapability<AddressSpace>(vmas_cap, kZionPerm_Write));
+
+  auto vmas = vmas_cap->obj<AddressSpace>();
+  return vmas->FreeAddressRange(req->lower_addr, req->upper_addr);
+}

zion/syscall/address_space.h

@@ -3,3 +3,4 @@
 #include "include/zcall.h"
 
 z_err_t AddressSpaceMap(ZAddressSpaceMapReq* req);
+z_err_t AddressSpaceUnmap(ZAddressSpaceUnmapReq* req);

zion/syscall/syscall.cpp

@@ -60,6 +60,7 @@ extern "C" z_err_t SyscallHandler(uint64_t call_id, void* req) {
     CASE(ThreadWait);
     // syscall/address_space.h
     CASE(AddressSpaceMap);
+    CASE(AddressSpaceUnmap);
     // syscall/memory_object.h
     CASE(MemoryObjectCreate);
     CASE(MemoryObjectCreatePhysical);