Writing x86_64 linux kernel module in assembler

I try write simple kernel module (v3.6) in nasm, but insmod say me:

$ sudo insmod ./hello.ko
insmod: ERROR: could not insert module ./hello.ko: Invalid module format
$ echo $?
1

I compile my code with:

$ nasm -f elf64 -o hello.m hello.asm
$ ld -m elf_x86_64 -r -o hello.ko hello.m

and my module code:

section .modinfo
__mod_kernel_version db "kernel_version=3.6.8", 0
__mod_license db "license=GPL", 0
__mod_author db "author=actics", 0
__mod_description db "description=hello world module in nasm", 0


section .data
init_mess db "init_module", 10, 0
cleanup_mess db "cleanup_module", 10, 0


section .text
global init_module
global cleanup_module

extern printk

init_module:
push rbp
mov rbp, rsp

xor rax, rax
mov rdi, init_mess
call printk

xor rax, rax
mov rsp, rbp
pop rbp
ret

cleanup_module:
push rbp
mov rbp, rsp

xor rax, rax
mov rdi, cleanup_mess
call printk

xor rax, rax
mov rsp, rbp
pop rbp
ret

Please help. In internets i found 1 link with equal code for 2.4, but he doesnt work too
My system - archlinux with 3.6.8 kernel

UPDATE:
in nasm forum i find thread with interesting solution. It's work for me, if my module do return 0 and exit :) But if i try add "extern printk" the insmod say me next:

ERROR: could not insert module hello.ko: Invalid parameters

What i'm doing wrong? my code:

[bits 64]

global init_module
global cleanup_module

;extern printk

section .modinfo
__mod_description8 db 'description=Simple module',0
align 16,db 0
__mod_author7 db 'author=That´s me',0
__mod_license6 db 'license=GPL',0
align 16,db 0
__module_depends db 'depends=',0
align 32,db 0
__mod_vermagic5 db 'vermagic=3.6.8-1-ARCH SMP preempt mod_unload modversions ',0 ;from a .ko module of my system

section __versions
____versions db 0xdf, 0xbc, 0xbf, 0x8c, 0, 0, 0, 0, "module_layout" ;from a .ko module of my system
align 64,db 0

section .data
init_mess db "init_module", 10, 0
cleanup_mess db "cleanup_module", 10, 0


section .text

init_module:
xor rax, rax
ret

cleanup_module:
xor rax, rax
ret

section .gnu.linkonce.this_module
times 24 db 0
__name: db 'Simple', 0
times (0x168 - 24 - 7) db 0
__init_module: dq init_module
times 0x2ac db 0
__cleanup_module: dq cleanup_module
times 1152 db 0

this code work with:
nasm -f elf64 hello.asm -o hello.o

but if i uncomment printk this no working!)

k you have to use gcc to compile it k and link it with the kernel directory...

change the Makefile to:

obj-m += memory_asm.o
memory_asm-objs := module.o main.o
$(KBUILD_EXTMOD)/main.o: $(src)/main.asm
nasm -f elf64 -o $@ $^ && echo "" > $(src)/.main.o.cmd

What I did was write a small C wrapper using the standard module macros and link it with the main module code that's written in asm. Use the normal kernel build system to build it.

*module.c:*
```c
#include <linux/module.h>
MODULE_AUTHOR("A. U. Thor");
MODULE_DESCRIPTION("Description");
MODULE_LICENSE("GPL");
extern int asm_init(void);
int main_init(void)
{
return asm_init();
}
module_init(main_init);
```
*main.asm:*
```x86asm
[bits 64]
global asm_init
asm_init:
xor rax, rax
ret
```
*Makefile:*

obj-m += test.o
test-objs := module.o main.o
$(KBUILD_EXTMOD)/main.o: main.asm
nasm -f elf64 -o $@ $^

obj-m += memory_asm.o
memory_asm-objs := module.o main.o
$(KBUILD_EXTMOD)/main.o: $(src)/main.asm
nasm -f elf64 -o $@ $^ && echo "" > $(src)/.main.o.cmd

Build using command: `make -C <path_to_kernel_src> M=$PWD`