# Re: \[PATCH\] mm: only enable sys\_pkey\* when ARCH\_HAS\_PKEYS

- From: Dave Hansen \<hidden\>
- Date: 2016-11-08 18:39:07 
- List: linux-api
- Page: https://ratatoskr.run/linux-api/2016/11/4870271
- Thread: https://ratatoskr.run/linux-api/2016/11/4865732/t.md

```text
On 11/08/2016 03:24 AM, Heiko Carstens wrote:
> Something like this:
> 
> diff --git a/mm/mprotect.c b/mm/mprotect.c
> index 11936526b08b..9fb86b107e49 100644
> --- a/mm/mprotect.c
> +++ b/mm/mprotect.c
> @@ -484,6 +484,8 @@ SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len,
>  	return do_mprotect_pkey(start, len, prot, -1);
>  }
>  
> +#ifdef CONFIG_ARCH_HAS_PKEYS
> +
>  SYSCALL_DEFINE4(pkey_mprotect, unsigned long, start, size_t, len,
>  		unsigned long, prot, int, pkey)
>  {
> @@ -534,3 +536,4 @@ SYSCALL_DEFINE1(pkey_free, int, pkey)
>  	 */
>  	return ret;
>  }
> +#endif /* CONFIG_ARCH_HAS_PKEYS */

That's fine with me, fwiw.  It ends up meaning that the config option
changes whether we get -ENOSPC vs. -ENOSYS, so the x86_32 behavior will
change, for instance.  But, I _think_ that's OK.
```