basic heap scafolding

TODO

@@ -22,7 +22,7 @@ Low-Level Hardware & Interrupts
 Memory Management
 [x] Physical memory manager (Bitmap or Buddy)
 [x] Paging (Recursive or Offset mapping)
-[ ] Kernel heap (kmalloc/kfree - Linked list or Slab)
+[-] Kernel heap (kmalloc/kfree - Linked list or Slab)
 [ ] Memory mapped I/O (MMIO) API for drivers
 [ ] VMM: Shared memory regions (For IPC/Framebuffers)
 [ ] VMM: Copy-on-Write (COW) support (Optional but good)

docs/memory-management.txt

@@ -48,3 +48,19 @@ A pointer to allocated memory or NULL.
 **Parameters**
 * `size_t count` - 
 
+**Description**
+This function allocates memory for `count` elements each of `size` bytes, zeroed-out memory.
+
+**Returns**
+A pointer to allocated memory or NULL.
+
+`void* kfree(void* p)`
+******************************************
+**Parameters**
+* `void* p` - 
+
+**Description**
+This function frees memory previously allocated using `k[m,z,c]alloc()`
+
+**Returns**
+Nothing

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) {}