Update kernel code

Core/Memory/ProgramBreak.cpp

@@ -0,0 +1,98 @@
+/*
+   This file is part of Fennix Kernel.
+
+   Fennix Kernel is free software: you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation, either version 3 of
+   the License, or (at your option) any later version.
+
+   Fennix Kernel is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with Fennix Kernel. If not, see <https://www.gnu.org/licenses/>.
+*/
+
+#include <memory.hpp>
+
+#include <assert.h>
+#include <errno.h>
+
+#include <debug.h>
+
+namespace Memory
+{
+	void *ProgramBreak::brk(void *Address)
+	{
+		if (HeapStart == 0x0 || Break == 0x0)
+		{
+			error("HeapStart or Break is 0x0");
+			return (void *)-EAGAIN;
+		}
+
+		/* Get the current program break. */
+		if (Address == nullptr)
+			return (void *)Break;
+
+		/* Check if the address is valid. */
+		if (Address < (void *)HeapStart)
+			return (void *)-ENOMEM;
+
+		Virtual vmm = Virtual(this->Table);
+
+		if (Address > (void *)Break)
+		{
+			/* Allocate more memory. */
+			size_t Pages = TO_PAGES(uintptr_t(Address) - Break);
+			void *Allocated = mm->RequestPages(Pages);
+			if (Allocated == nullptr)
+				return (void *)-ENOMEM;
+
+			/* Map the allocated pages. */
+			for (size_t i = 0; i < Pages; i++)
+			{
+				void *VirtAddr = (void *)(Break + (i * PAGE_SIZE));
+				void *PhysAddr = (void *)(uintptr_t(Allocated) + (i * PAGE_SIZE));
+				vmm.Map(VirtAddr, PhysAddr, RW | US);
+			}
+
+			Break = (uint64_t)Address;
+			return (void *)Break;
+		}
+		else if (Address < (void *)Break)
+		{
+			/* Free memory. */
+			size_t Pages = TO_PAGES(uintptr_t(Address) - Break);
+			mm->FreePages((void *)Break, Pages);
+
+			/* Unmap the freed pages. */
+			for (size_t i = 0; i < Pages; i++)
+			{
+				uint64_t Page = Break - (i * 0x1000);
+				vmm.Unmap((void *)Page);
+			}
+
+			Break = (uint64_t)Address;
+			return (void *)Break;
+		}
+
+		assert(false);
+	}
+
+	ProgramBreak::ProgramBreak(PageTable *Table, MemMgr *mm)
+	{
+		assert(Table != nullptr);
+		assert(mm != nullptr);
+
+		this->Table = Table;
+		this->mm = mm;
+	}
+
+	ProgramBreak::~ProgramBreak()
+	{
+		/* Do nothing because MemMgr
+			will be destroyed later. */
+	}
+}