On Fri, May 15, 2015 at 04:17:46PM +0100, Peter Maydell wrote: > On 15 May 2015 at 16:14, Alex Bennée <alex.bennee@xxxxxxxxxx> wrote: > > > > Mark Rutland <mark.rutland@xxxxxxx> writes: > > > >> On Fri, May 15, 2015 at 03:27:06PM +0100, Alex Bennée wrote: > >>> +/* > >>> + * See v8 ARM ARM D7.3: Debug Registers > >>> + * > >>> + * The control registers are architecturally defined as 32 bits but are > >>> + * stored as 64 bit values alongside the value registers. This is done > >> > >> Stale comment? They're stored as __u32 below. > > > > Gah yes it is. > > > >> It's possible that the registers could grow in future as happened in the > >> case of CLIDR_EL1, so it might be worth treating system registers > >> generally as u64 values. > > > > Really? I mean the existing debug *control* registers have reserved bits > > 24-31 so there is space for expansion. > > Other places in the userspace ABI which deal with sysregs (notably > ONE_REG) consistently define them all as 64-bit Also for pt_regs.pstate. I just spotted that in user_hwdebug_state in ptrace.h we seem to expose the debug control regsiters as __u32 already, aalong with some other registers. So we're already inconsistent w.r.t. how we expose those registers, and I'm not sure what we'd do elsewhere if any registers got expanded. :/ Mark. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
