RFC: HW watchpoints and single stepping for ARMv6/v7

Zbigniew Bodek zbb at semihalf.com
Mon Nov 30 14:41:56 UTC 2015

Hello again,

It seems that this is the last chance to test this patch on other
platforms than Rpi, Arndale and Pandaboard.
Please check out this https://reviews.freebsd.org/D4037
I will be grateful if you had  a chance to test this on something else
than the above mentioned.

Best regards

2015-10-31 17:21 GMT+01:00 Zbigniew Bodek <zbb at semihalf.com>:
> 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

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