RFC: HW watchpoints and single stepping for ARMv6/v7

[Zbigniew Bodek]

Hello again,

I should have post some more information about testing this patch. Here it goes:
------------------------------------------------------------------
One can enter kernel debugger by one of those:

press: ~, ctrl + b
or
type: sysctl -w debug.kdb.enter=1

You can then set a HW watchpoint on any memory location at <address>
by invoking following command in KDB:
db> hwatch <address>, <size>

<size> parameter is optional, the default is 4.

To display watchpoints:
db> show watch

To remove watchpoint:
db> dhwatch <address>

Press "c" to continue.

------------------------------------------------------------------
While in KDB you can step through the kernel code using "s" BUT you
need to apply a dependent patch: https://reviews.freebsd.org/D4036
otherwise you will cause the kernel panic.

Thanks again
zbb

2015-10-30 17:25 GMT+01:00 Zbigniew Bodek <zbb at semihalf.com>:
> Hello,
>
> We would like to add HW watchpoints and HW single step support to ARMv6 kernel.
> Please check this review: https://reviews.freebsd.org/D4037
>
> Since there are differences between debug architectures on ARM (v6,
> v6.1, v7, v7.1) I would like to ask for some testing on your machines.
> I was able to test this on Pandaboard and Arndale but please check
> whether this works on your targets as well.
>
> Rise a red flag if you see any issues or in worst case scenario -
> "undefined instruction" error.
>
> Best regards
> zbb