Don't leak page frames

src/arch/x86/paging.cpp

@@ -11,8 +11,10 @@
 #include "FDT.hpp"
 
 // Returns a free page frame in HHDM
-static uint64_t *get_free_frame() {
+uint64_t *AddressSpace::get_free_frame() {
     uint64_t *res = static_cast<uint64_t *>(get4k());
+    if (_taken_pages.get())
+        _taken_pages->push_back(res);
     assert(res != nullptr);
     for (int j = 0; j < 512; j++)
         res[j] = 0;
@@ -29,6 +31,9 @@ static inline void invlpg(void *m) {
 
 AddressSpace::AddressSpace() {
     PML4 = static_cast<uint64_t *>(get4k());
+    assert(_taken_pages.get() == nullptr);
+    _taken_pages = UniquePtr(new cgistd::vector<uint64_t *>());
+    _taken_pages->push_back(PML4);
     for (int j = 0; j < 512; j++)
         PML4[j] = 0;
 }
@@ -36,8 +41,9 @@ AddressSpace::AddressSpace() {
 AddressSpace::AddressSpace(uint64_t *PML4) : PML4(PML4) {}
 
 AddressSpace::~AddressSpace() {
-    // TODO:
-    free4k(PML4);
+    if (_taken_pages.get()) {
+        for (const auto &p: *_taken_pages) free4k(p);
+    }
 }
 
 void *AddressSpace::virt2real(void *virt) {

src/arch/x86/paging.hpp

@@ -11,6 +11,8 @@
 #include "PointersCollection.hpp"
 #include "mutex.hpp"
 
+#include <stl/vector>
+
 #define PAGE_SIZE   4096
 
 #define KERN_V2P(a) ((((uintptr_t) (a) - (uintptr_t) kernel_virt_base) + (uintptr_t) kernel_phys_base))
@@ -44,11 +46,15 @@ public:
     FDT *getFdt();
 
 private:
-    // Pointer to PML4 in HHDM
-    uint64_t      *PML4;
+    uint64_t *get_free_frame();
 
-    UniquePtr<FDT> _fdt;
-    Mutex          _fdtLock;
+    // Pointer to PML4 in HHDM
+    uint64_t                             *PML4;
+
+    UniquePtr<FDT>                        _fdt;
+    Mutex                                 _fdtLock;
+
+    UniquePtr<cgistd::vector<uint64_t *>> _taken_pages;
 };
 
 extern AddressSpace *KERN_AddressSpace;