Re: [PATCH 27/31] Add debugger entry points for M68K

[Jeffrey Merkey]

On 1/28/16, Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote:
> Hi Jeffrey,
>
> CC linux-arch
>
> On Thu, Jan 28, 2016 at 8:47 PM, Jeffrey Merkey <jeffmerkey@xxxxxxxxx>
> wrote:
>> This patch series adds an export which can be set by system debuggers to
>> direct the hard lockup and soft lockup detector to trigger a breakpoint
>> exception and enter a debugger if one is active.  It is assumed that if
>> someone sets this variable, then an breakpoint handler of some sort will
>> be actively loaded or registered via the notify die handler chain.
>>
>> This addition is extremely useful for debugging hard and soft lockups
>> real time and quickly from a console debugger.
>
> As there's no cover letter, I'm giving my (mostly general) comments in a
> reply to this patch.
>
>> Signed-off-by: Jeffrey Merkey <jeffmerkey@xxxxxxxxx>
>> ---
>>  arch/m68k/include/asm/kdebug.h | 4 ++++
>>  1 file changed, 4 insertions(+)
>>  create mode 100644 arch/m68k/include/asm/kdebug.h
>>
>> diff --git a/arch/m68k/include/asm/kdebug.h
>> b/arch/m68k/include/asm/kdebug.h
>> new file mode 100644
>> index 0000000..5d09de1
>> --- /dev/null
>> +++ b/arch/m68k/include/asm/kdebug.h
>> @@ -0,0 +1,4 @@
>> +
>> +static inline void arch_breakpoint(void)
>> +{
>> +}
>
> No include guards in the newly added header files?
>
> This new file will conflict with arch/m68k/include/asm/Kbuild, which has:
>
>     generic-y += kdebug.h
>
> What about putting the dummy arch_breakpoint() in
> include/asm-generic/kdebug.h
> instead, like
>
>     #ifndef arch_breakpoint
>     static inline void arch_breakpoint(void)
>     {
>     }
>     #endif
>
> Architectures providing their own version have to #define arch_breakpoint.
>
> Gr{oetje,eeting}s,
>
>                         Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 --
> geert@xxxxxxxxxxxxxx
>
> In personal conversations with technical people, I call myself a hacker.
> But
> when I'm talking to journalists I just say "programmer" or something like
> that.
>                                 -- Linus Torvalds
>

That's a great idea and suggestion.  I'll move it to the asm-generic
directory and files and look it implementing it as a macro.  This
suggestion is added to the list of changes for the next version of
this patch series.

:-)

Jeff