Re: [PATCH RFC v1] m68k: kernel/traps.c - only force 030 bus error if PC not in exception table

[Michael Schmitz <schmitzmic@gmail.com>]

Hi Geert,

thanks for your feedback!

On 28/02/23 09:19, Geert Uytterhoeven wrote:
> Hi Michael,
>
> On Wed, Feb 22, 2023 at 8:52 PM Michael Schmitz <schmitzmic@gmail.com> wrote:
>> __get_kernel_nofault() does copy data in supervisor mode when
>> forcing a task backtrace dump through the sysrq trigger.
>>
>> Our 030 bus error handler is ill equipped to deal with this:
>>
>> Whenever ssw indicates a kernel mode access on a data fault,
>> we don't even attempt to handle the fault and instead send
>> a bus error signal (or panic). As a result, the check for
>> exception handling at the fault PC (buried in send_sig_fault()
>> which gets called from do_page_fault() eventually) is never
>> used.
>>
>> Both 040 and 060 access error handlers do not care whether
>> a fault happened on supervisor mode access, and will call
>> do_page_fault() even on those.
>>
>> Add a check in bus_error030 to call do_page_fault() in case
>> we do have an entry for the fault PC in our exception table.
>>
>> Tested on 030 Atari Falcon.
> Thanks for your patch!
>
>> Signed-off-by: Michael Schmitz <schmitzmic@gmail.com># Please enter the commit message for your changes. Lines starting
> Please remove the comment ;-)

Done that already for v2.

>
>> CC: Eero Tamminen <oak@helsinkinet.fi>
>> CC: Finn Thain <ftain@linux-m68k.org>
>> CC: Andreas Schwab <schwab@linux-m68k.org>
>> CC: Geert Uytterhoeven <geert@linux-m68k.org>
>> Link: https://lore.kernel.org/r/daca2f68-19fa-a2b6-97c6-16b5b7e26afe@helsinkinet.fi
> 404
>
> I assume that a message from debian-68k?

No, oddly enough that is a message that I have received with CC to 
linux-m68k (but not from vger!). And mail-archive.com has it:

https://www.mail-archive.com/linux-m68k@vger.kernel.org/msg13081.html

And also on marc.info:

https://marc.info/?l=linux-m68k&m=155477039405576&w=2

Later one with an experimental patch of mine:

https://marc.info/?l=linux-m68k&m=155494864731013&w=2

None of these messages show up on a search of lore...

What source do you prefer - marc.info or mail-archive.com?

Cheers,

     Michael


> Do you have a https://lists.debian.org/debian-68k/ link?
>
> Gr{oetje,eeting}s,
>
>                          Geert
>