Re: [PATCH 10/26] x86, pkeys: notify userspace about protection key faults

From: Ingo Molnar
Date: Wed Sep 23 2015 - 04:06:19 EST



* Dave Hansen <dave@xxxxxxxx> wrote:

> On 09/22/2015 01:27 PM, Thomas Gleixner wrote:
> >> >
> >> > So I defined all the kernel-internal types as u16 since I *know* the
> >> > size of the hardware.
> >> >
> >> > The user-exposed ones should probably be a bit more generic. I did just
> >> > realize that this is an int and my proposed syscall is a long. That I
> >> > definitely need to make consistent.
> >> >
> >> > Does anybody care whether it's an int or a long?
> > long is frowned upon due to 32/64bit. Even if that key stuff is only
> > available on 64bit for now ....
>
> Well, it can be used by 32-bit apps on 64-bit kernels.
>
> Ahh, that's why we don't see any longs in the siginfo. So does that
> mean 'int' is still our best bet in siginfo?

Use {s|u}{8|16|32|64} integer types in ABI relevant interfaces please, they are
our most unambiguous and constant types.

Here that would mean s32 or u32?

Thanks,

Ingo
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