Re: [PATCH 0/3 v3] [AArch64] Support tagged pointer

Omair Javaid
2018-04-11T00:16:08Z

On 8 December 2017 at 22:31, Yao Qi <qiyaoltc@gmail.com> wrote:

> On Fri, Dec 8, 2017 at 10:04 AM, Yao Qi <qiyaoltc@gmail.com> wrote:
> > ARMv8 supports tagged address, that is, the top one byte in address
> > is ignored. It is always enabled on aarch64-linux. See
> > https://www.kernel.org/doc/Documentation/arm64/tagged-pointers.txt
> >
> > Some parts of GDB related to address are updated in this patch series,
> >
> > - Memory access, like command 'x',
> > - Setting hw breakpoint on some address,
> > - Setting watchpoint on some address,
> >
>
> I pushed them in as we are close to branching. We can still keep the
> addr_bits_remove vs significant_addr_bit conversation ongoing.
>

This patch has broken kernel debugging using kgdb and openOCD.

Tagged address should only be considered while debugging only user-space
programs on linux.

I still need to understand the full background behind this patch but can we
pull it out of 8.1 release to make sure kernel debugging works?

--
> Yao (齐尧)
>