feat: update Virtual Memory Manager to use page-based allocation and introduce VmFaultCause enum

1 files changed, 22 insertions, 8 deletions

diff --git a/na/include/lume/vmm.h b/na/include/lume/vmm.h
index ec26d6a..85988e4 100644
--- a/na/include/lume/vmm.h
+++ b/na/include/lume/vmm.h
@@ -26,6 +26,12 @@ inline constexpr uint64 VM_WRITE = (1ULL << 1);
 inline constexpr uint64 VM_EXEC  = (1ULL << 2);
 inline constexpr uint64 VM_USER  = (1ULL << 3);
 
+enum class VmFaultCause : uint8 {
+    Read  = 0,
+    Write = 1,
+    Exec  = 2,
+};
+
 /* Forward declarations */
 struct VmSpace;
 struct VmAreaStruct;
@@ -48,13 +54,16 @@ struct VmAreaStruct {
  *
  * Lock contract:
  *   Holds: lock (internal spinlock)
- *   May acquire: PMM global lock (via pmm_alloc_frame inside page fault)
+ *   May acquire: PMM global lock (via pmm_alloc_page inside page fault)
  *   Callers must NOT hold: PMM lock (lock ordering: VmSpace -> PMM)
  */
 struct VmSpace {
     uint64 root_pa;         // SV39 root page table physical address
     struct rb_root vma_tree; // Red-black tree of VmAreaStructs
     Spinlock lock;          // Protects vma_tree mutations
+
+    uint64 brk_start;        // Start of heap (page-aligned)
+    uint64 brk_end;          // Current heap end (page-aligned)
     
     // Create a brand new VmSpace (allocates root pagetable)
     static VmSpace* create();
@@ -72,18 +81,23 @@ void vmm_init_ap();
 /* Map MMIO device region to the active kernel page table */
 void vmm_map_kernel_mmio(uint64 pa, uint64 size);
 
-/* Query frame_map allocation (set by vmm_init, read by pmm_init).
- * Returns the PA, byte size, and frame count of the vmemmap region. */
-uint64 vmm_get_frame_map_pa();
-uint64 vmm_get_frame_map_size();
-uint64 vmm_get_num_frames();
+/* Query page_map allocation (set by vmm_init, read by pmm_init).
+ * Returns the PA, byte size, and page count of the vmemmap region. */
+uint64 vmm_get_page_map_pa();
+uint64 vmm_get_page_map_size();
+uint64 vmm_get_num_pages();
 
 /* User space memory management (VMA & Demand Paging) */
 int vmm_map_user(VmSpace* space, uint64 va, uint64 len, uint64 perm);
 int vmm_unmap_user(VmSpace* space, uint64 va, uint64 len);
+int vmm_protect_user(VmSpace* space, uint64 va, uint64 len, uint64 perm);
+
+/* VMA helpers for mmap/mprotect implementations */
+uint64 mm_find_free_va(VmSpace* space, uint64 length, uint64 align);
+bool vma_range_covered(VmSpace* space, uint64 start, uint64 end);
 
-/* Handle user page fault (lookup VMA -> allocate frame -> map) */
-int vmm_handle_page_fault(VmSpace* space, uint64 fault_addr, uint64 cause);
+/* Handle user page fault (lookup VMA -> allocate page -> map) */
+int vmm_handle_page_fault(VmSpace* space, uint64 fault_addr, VmFaultCause cause);
 
 /* Clone an address space for fork() */
 VmSpace* vmm_clone(VmSpace* parent_space);