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 (which makes sense anyway since the ISA only provides 64-bit accessors to them). "Architecturally 32 bits" only means "top 32 bits reserved". -- PMM -- 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
