On Tue, Jul 25, 2017 at 03:59:04PM +0100, Mark Rutland wrote: > On Tue, Jul 25, 2017 at 01:11:48PM +0100, Dave Martin wrote: > > On Mon, Apr 03, 2017 at 04:19:23PM +0100, Mark Rutland wrote: > > > +/* > > > + * The pointer bits used by a pointer authentication code. > > > + * If we were to use tagged pointers, bits 63:56 would also apply. > > > + */ > > > +#define ptrauth_pac_mask() GENMASK(54, VA_BITS) > > > > Tagged pointers _are_ enabled for userspace by default, no? > > Yes; I'd meant s/tagged/untagged/. > > I've corrected this to: > > /* > * The EL0 pointer bits used by a pointer authentication code. > * This is dependent on TBI0 being enabled, or bits 63:56 would also apply. > */ Yes, that's better. If we do enable untagged pointers for userspace at some point though, this is likely to be missed. I don't have a good answer to this. > > > diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h > > > index b59ee07..cae3d1e 100644 > > > --- a/include/uapi/linux/elf.h > > > +++ b/include/uapi/linux/elf.h > > > @@ -414,6 +414,7 @@ > > > #define NT_ARM_HW_BREAK 0x402 /* ARM hardware breakpoint registers */ > > > #define NT_ARM_HW_WATCH 0x403 /* ARM hardware watchpoint registers */ > > > #define NT_ARM_SYSTEM_CALL 0x404 /* ARM system call number */ > > > +#define NT_ARM_PAC_MASK 0x405 /* ARM pointer authentication code masks */ > > > > The is the value tentatively assigned to NT_ARM_SVE. > > I must've generated this patch before I corrected this; my local branch > (and kernel.org) have 0x406 here. > > Sorry about that. Shame, I had a rant about pragmatism prepped and ready ;) Cheers ---Dave
