# Does SMP work at all on 40x ?

- From: Christophe Leroy \<hidden\>
- Date: 2019-01-30 07:18:12 
- List: linuxppc-dev
- Page: https://ratatoskr.run/linuxppc-dev/2019/01/9508142
- Thread: https://ratatoskr.run/linuxppc-dev/2019/01/9508142/t.md

```text
In transfer_to_handler() (entry_32.S), we have:

#if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
...
#ifdef CONFIG_SMP
	CURRENT_THREAD_INFO(r9, r1)
	lwz	r9,TI_CPU(r9)
	slwi	r9,r9,3
	add	r11,r11,r9
#endif
#endif

When running this piece of code, MMU translation is off. But r9 contains the virtual addr of current_thread_info, so unless I miss something, this cannot work on the 40x, can it ?

On CONFIG_BOOKE it works because phys addr = virt addr

Christophe
```