fix: various fixes

kernel/src/Memory/PageFrameAllocator.cpp

@@ -105,4 +105,21 @@ namespace Memory {
             Free((void*)(uint64_t)ptr + (0x1000 * n));
         }
     }
+
+    void PageFrameAllocator::GetStats(Zenith::MemStats* out) {
+        if (!out) return;
+        Lock.Acquire();
+        uint64_t freeBytes = 0;
+        Page* current = head.next;
+        while (current != nullptr) {
+            freeBytes += current->size;
+            current = current->next;
+        }
+        Lock.Release();
+
+        out->totalBytes = g_section.size;
+        out->freeBytes = freeBytes;
+        out->usedBytes = g_section.size > freeBytes ? g_section.size - freeBytes : 0;
+        out->pageSize = 0x1000;
+    }
 };

kernel/src/Memory/PageFrameAllocator.hpp

@@ -6,6 +6,7 @@
 
 #pragma once
 #include "Memmap.hpp"
+#include <Api/Syscall.hpp>
 
 #include <CppLib/Spinlock.hpp>
 
@@ -27,6 +28,8 @@ public:
         void* ReallocConsecutive(void* ptr, int n);
         void Free(void* ptr);
         void Free(void* ptr, int n);
+
+        void GetStats(Zenith::MemStats* out);
     };
 
     extern PageFrameAllocator* g_pfa;