On Mon, Oct 17, 2016 at 09:16:48AM +0200, Heiko Carstens wrote:
> On Fri, Oct 14, 2016 at 02:26:24PM -0400, Dave Jones wrote:
> > This easy-to-trigger warning shows up instantly when running
> > Trinity on a kernel with CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS disabled.
> >
> > At most this should have been a printk, but the -EINVAL alone should be more
> > than adequate indicator that something isn't available.
> >
> > Signed-off-by: Dave Jones <davej@xxxxxxxxxxxxxxxxx>
> >
> > diff --git a/include/linux/pkeys.h b/include/linux/pkeys.h
> > index e4c08c1ff0c5..a1bacf1150b2 100644
> > --- a/include/linux/pkeys.h
> > +++ b/include/linux/pkeys.h
> > @@ -25,7 +25,6 @@ static inline int mm_pkey_alloc(struct mm_struct *mm)
> >
> > static inline int mm_pkey_free(struct mm_struct *mm, int pkey)
> > {
> > - WARN_ONCE(1, "free of protection key when disabled");
> > return -EINVAL;
> > }
>
> FWIW, are all architectures supposed to wire these new system calls up?
>
> I decided to ignore these on s390 since we can't make any sane use of
> them. However mips has them already wired up.
>
> The only difference on s390 (and any other architecture without memory
> protection keys with x86 like semantics) would be that pkey_alloc/pkey_free
> will return -EINVAL instead of -ENOSYS and that we have a new mprotect
> wrapper called pkey_mprotect, if being called with a pkey parameter of -1.
What I wrote is of course not correct...
There can't be any -ENOSYS if the system call isn't wired up, since the
system call number hasn't been allocated at all for an architecture.
But the question remains: should these be wired up on all architectures?
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