basic heap scafolding

kernel/include/kmalloc.h

@@ -0,0 +1,17 @@
+#ifndef _KMALLOC_H
+#define _KMALLOC_H
+
+#include "types.h"
+
+// This function allocates size bytes of contiguous memory.
+// Returns a pointer to allocated memory or NULL.
+void* kmalloc(size_t size);
+
+// This function allocates size bytes of contiguous, zeroed-out memory.
+// Returns a pointer to allocated memory or NULL.
+void* kzalloc(size_t size);
+
+// This function allocates memory for count elements each of size bytes, zeroed-out memory.
+// Returns a pointer to allocated memory or NULL.
+void* kcalloc(size_t count, size_t size);
+#endif

kernel/src/kmalloc.c

@@ -0,0 +1,35 @@
+#include "types.h"
+#include <kmalloc.h>
+#include <string.h>
+// this file contains SLUB inspired HEAP allocator
+void* freelist = NULL;
+
+void* kcalloc(size_t count, size_t size) {
+	size_t size_to_alloc;
+	__asm__ volatile goto(".intel_syntax noprefix\n\t"
+			      "mov rax, %1\n\t"
+			      "mov rdx, %2\n\t"
+			      "mul rdx\n\t"
+			      "jo %l[overflow]\n\t"
+			      "mov %0, rax\n\t"
+			      ".att_syntax prefix\n\t"
+			      : "=r"(size_to_alloc)
+			      : "r"(count), "r"(size)
+			      : "rax", "rdx", "cc"
+			      : overflow);
+	return kzalloc(size_to_alloc);
+
+overflow:
+	return NULL;
+}
+
+void* kzalloc(size_t size) {
+	void* allocated = kmalloc(size);
+	if (!allocated) {
+		return NULL;
+	}
+	memset(allocated, 0, size);
+	return allocated;
+}
+
+void* kmalloc(size_t size) {}