Re: 64-bit Addresses in remote protocol

[Joel Sherrill <joel@rtems.org>]

On Mon, Mar 22, 2021, 12:32 PM Luis Machado <luis.machado@linaro.org> wrote:

> Hi,
>
> On 3/22/21 1:55 PM, Joel Sherrill wrote:
> > Hi
> >
> > Over at RTEMS, we are looking at some warnings in our debug
> > server and wondering if fields described as "addr" in the gdb
> > protocol should be treated 64-bits when that target has 64-bit
> > addresses like the aarch64.
>
> If the inferior is using 64-bit addresses, then the remote protocol will
> also use 64-bit addresses. If we have a 32-bit inferior running on
> aarch64 hardware, we'll have 32-bit addresses over the remote protocol
> as well.
>
> Even when we're using 64-bit addresses, the remote protocol may not pad
> it with zeroes to make it 64-bit, but it should still be handled as 64-bit.
>
> Does that help?
>

I think it does. Sounds right to treat it as uintptr_t when decoding it.

Unfortunately I think this means a review of our gdb server since it uses a
decode uint method a lot and each case will need to be checked to see if it
is called for an address.

Was there somewhere in the gdb documentation this was and I missed it? My
read of the protocol description focused on it as an ASCII command and not
the types they mapped to. But I admit that I might have missed something.

Thanks.

--joel


> >
> > Technically, we are looking at sweeping through our gdb server
> > and using  uintptr_t for addresses where uint32_t has been
> > ok before.
> >
> > But I wanted to make sure that our assumption that "addr" means
> > a valid target address which means it can be 32- or 64- bits based
> > on the target.
> >
> > Thanks.
> >
> > --joel
> > RTEMS
> >
>