On Mon, Mar 20, 2017 at 11:54:03AM +0100, Mark Kettenis wrote:
> > Date: Mon, 20 Mar 2017 13:31:32 +1100
> > From: Jonathan Gray <j...@jsg.id.au>
> > Cc: tech@openbsd.org
> > Mail-Followup-To: Mark Kettenis <mark.kette...@xs4all.nl>, tech@openbsd.org
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> > On Mon, Mar 20, 2017 at 01:35:04AM +0100, Mark Kettenis wrote:
> > > It turns out that pretty much all relevant aarch64 OSes use the same
> > > layout for transferring registers in their debug interfaces. Except
> > > for us. That doesn't make sense and would mean I'd have to do
> > > additional work in my lldb porting efforts.
> > >
> > > Diff below revises "struct reg" for amd64 to be compatible with what
> > > NetBSD provides. That just matches our naming conventions for struct
> > > reg better. The actual names are largely irrelevant as debuggers
> > > hardcode the layouts anyway to support cross-debugging.
> > >
> > > This struct isn't actually used yet, so these changes don't really
> > > have any ABI consequences. But once this is in, I'm planning on
> > > making core dumps and ptrace actually work on arm64.
> > >
> > > ok?
> >
> > It looks like NetBSD just has a cross compiled toolchain
> > nothing that runs on actual hardware.
> >
> > Given FreeBSD does I'd consider that more relevant, and it
> > has:
> >
> > struct reg {
> > uint64_t x[30];
> > uint64_t lr;
> > uint64_t sp;
> > uint64_t elr;
> > uint32_t spsr;
> > };
> >
> > struct fpreg {
> > __uint128_t fp_q[32];
> > uint32_t fp_sr;
> > uint32_t fp_cr;
> > };
>
> The FreeBSD definition is equivalent to the NetBSD one:
>
> lr == x30
> elr == pc
>
> It's just that the names assigned by NetBSD make a little bit more
> sense and follow the pattern we use on many other architectures.
>
> NetBSD also includes the userland per-thread-register which I think is
> a good idea.
>
Naming and order realistically doesn't matter that much, If it is easier to
move registers around to match a userland structure in process_*regs(),
that is reasonable. That said: the more I have followed NetBSD's lead in the
past, the more I have regretted it later.
Including the thread pointer would seem to make sense, but there is there
a proc vs process issue there (thread vs p
using __uint128_t for FPU is a lot better than the uint64 [64] that is there
now.
Dale Rahn dr...@dalerahn.com
