Mark Rutland <mark.rutland@xxxxxxx> writes: > 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. I thought those where ptrace specific fields which then get munged into the final values inside the kernel? > > 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. -- Alex Bennée -- 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
