mm: add page frame allocator

kernel/mm/CMakeLists.txt

@@ -0,0 +1,17 @@
+# See the end of this file for copyright and license terms.
+
+target_sources(gay_kernel PRIVATE
+    kmalloc.c
+)
+
+# This file is part of GayBSD.
+# Copyright (c) 2021 fef <owo@fef.moe>.
+#
+# GayBSD is nonviolent software: you may only use, redistribute, and/or
+# modify it under the terms of the Cooperative Nonviolent Public License
+# (CNPL) as found in the LICENSE file in the source code root directory
+# or at <https://git.pixie.town/thufie/npl-builder>; either version 7
+# of the license, or (at your option) any later version.
+#
+# GayBSD comes with ABSOLUTELY NO WARRANTY, to the extent
+# permitted by applicable law.  See the CNPL for details.

kernel/mm/kmalloc.c

@@ -0,0 +1,44 @@
+/* See the end of this file for copyright and license terms. */
+
+#include <arch/page.h>
+
+#include <gay/config.h>
+#include <gay/kprintf.h>
+#include <gay/mm.h>
+#include <gay/types.h>
+
+/* yeah this is probably the most stupid memory allocator there is */
+
+void *kmalloc(size_t size, enum mm_flags flags)
+{
+	if (flags != MM_KERNEL) {
+		kprintf("invalild flags passed to kmalloc()\n");
+		return NULL;
+	}
+
+	if (size > PAGE_SIZE) {
+		kprintf("Requested alloc size of %u > PAGE_SIZE, i can't do that yet qwq\n", size);
+		return NULL;
+	}
+
+	return get_page();
+}
+
+void kfree(void *ptr)
+{
+	put_page(ptr);
+}
+
+/*
+ * This file is part of GayBSD.
+ * Copyright (c) 2021 fef <owo@fef.moe>.
+ *
+ * GayBSD is nonviolent software: you may only use, redistribute, and/or
+ * modify it under the terms of the Cooperative Nonviolent Public License
+ * (CNPL) as found in the LICENSE file in the source code root directory
+ * or at <https://git.pixie.town/thufie/npl-builder>; either version 7
+ * of the license, or (at your option) any later version.
+ *
+ * GayBSD comes with ABSOLUTELY NO WARRANTY, to the extent
+ * permitted by applicable law.  See the CNPL for details.
+ */