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

Omair Javaid
2018-04-11T00:37:13Z

On 11 April 2018 at 05:15, Omair Javaid <omair.javaid@linaro.org> wrote:

> 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?
>
>
Just found out that patch series posted here
https://sourceware.org/ml/gdb-patches/2017-12/msg00160.html does change
aarch64-linux-tdep only.
But the committed version here
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commit;h=a738ea1d41daeec0cccb4ab6671f4f6d53bd9e18
is
applying it to aarch64-tdep

> --
>> Yao (齐尧)
>>
>
>