Re: HW watchpoint on Linux/ARM

[Christian Gagneraud <chgans at gmail dot com>]

On 16 July 2017 at 20:52, Peter Schauer <peterschauer@gmx.net> wrote:
>> But on i.mx6, it does. From memory, the kernel told me that I have
>> access to 5 HW breakpoints and 1 HW watchpoint (I don't have the board
>> at hand, but will post details on Monday).
>
> I had the same problem with an i.mx6 board three years ago.
> I don't remember all the details, but it had to do with the
> ARM secure debug mode, which is active when the SPIDEN pin is pulled low
> in hardware.
>
> I had a kernel hack back then, which enabled the hardware break mechanism
> even if the SPIDEN pin is pulled low, but it disables the secure debug mode,
> and worked only for my arm architecture (I couldn't test others), so
> I didn't post it to the kernel group.
>
> If your problem is caused by SPIDEN low, and you are interested in
> the kernel hack, please let me know.
> I could also send you a detailed analysis of the problem in german,
> in case you are interested.

Hi Peter,

Yes please, I'm interested by your hacky patch, and i'll take the
german analysis too! ;)

Thanks,
Chris

>
> --
> Peter Schauer                   Peter.Schauer@mytum.de