Re: [PATCH 2/3 v2] Define _KMEMUSER in arm-nbsd-nat.c

Kamil Rytarowski
2020-01-24T16:37:06Z

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On 24.01.2020 17:01, Christian Biesinger wrote:
> On Fri, Jan 24, 2020 at 4:49 PM Kamil Rytarowski <n54@gmx.com> wrote:
>>
>> On 24.01.2020 16:35, Christian Biesinger via gdb-patches wrote:
>>> On Fri, Jan 24, 2020 at 4:23 PM Kamil Rytarowski <n54@gmx.com> wrote:
>>>>
>>>> On 24.01.2020 15:53, Christian Biesinger via gdb-patches wrote:
>>>>> Hi Kamil,
>>>>>
>>>>> I have a related question. NetBSD applied this patch:
>>>>> https://www.mail-archive.com/tech@openbsd.org/msg44100.html
>>>>>
>>>>
>>>> Is this the right link?
>>>
>>> Yeah -- that patch changes a system header at the top and patches GDB
>>> at the bottom.
>>>
>>
>> This is not a change in NetBSD, so it is unrelated.
>
> My apologies, I completely misread that. I'll see if I can find where
> NetBSD changed their FP register data structure, or perhaps your
> downstream patch will still work (although that probably has to come
> from one of y'all for copyright reasons?)
>

Please cherry-pick what you need and I will find the original author.
Many people in NetBSD have FSF papers done.

>>>>> Do you know which NetBSD version that shipped in? Can we apply that
>>>>> patch to GDB as-is or should we attempt to support the older struct
>>>>> layout as well?
>>>>
>>>> Please go for the current FPU layout on NetBSD. Massive ptrace(2) fixes
>>>> were introduced in NetBSD-8 and later. Soon NetBSD 7.x will go EOL
>>>> (after releasing 9.0, rc2 is planned soon).
>>>
>>> OK, great. Thanks.
>>>
>>>> In LLDB we support NetBSD 9.0 or newer. In GDB we should keep the same
>>>> minimal requirements and deal with older NetBSD versions (if at all)
>>>> with downstream patches.
>>>>
>>>> We have got a pile of local GDB patches.
>>>
>>> OK. Maybe I should look through those at some point... I was
>>> surprised that NetBSD apparently has an oldish GDB if
>>> http://ftp.netbsd.org/pub/pkgsrc/current/pkgsrc/devel/gdb/README.html
>>> is correct (8.1)
>>>
>>>> There is also a functional gdbserver implementation on NetBSD/amd64 and
>>>> I intend to upstream it. (Help wanted! Would you be interested in this
>>>> and in upstreaming?)
>>>>
>>>> The patches are located here:
>>>>
>>>> https://github.com/NetBSD/pkgsrc-wip/tree/master/gdb-netbsd/patches
>>>>
>>>> * with core/basic features... but it is difficult as there is no OS with
>>>> finished transition...
>>>> https://sourceware.org/gdb/wiki/LocalRemoteFeatureParity
>>>
>>> I can definitely not commit to upstreaming the gdbserver. I am only
>>> looking at NetBSD because I wanted to remove a deprecated function in
>>> GDB, and one of the two callers is in NetBSD ARM code. So, I wanted to
>>> build ARM NetBSD first so I can test if it still works after that
>>> change. But I can't commit to any further NetBSD work.
>>>
>>
>> OK, thanks!
>>
>>> BTW, is there a reason why your patches have one .patch per changed
>>> file? I usually find it easier to follow them if they are instead
>>> grouped by some kind of topic per patch.
>>>
>>
>> This is a convention in pkgsrc and it is practical for its use-case.
>
> OK. Some of those patches should be upstreamable very easily. For some
> others it would be helpful to have a description & I guess a copyright
> assignment.
>

My intention was to revamp the general NetBSD support from native-only
to gdbserver... (same like lldb-server).. and it would result in deep
rewrite of the current code, but there is work in progress status in
Linux so it does not help.

> I also noticed that some of those files are 0 bytes and could probably
> be deleted? And this does not seem necessary:
> https://github.com/NetBSD/pkgsrc-wip/blob/master/gdb-netbsd/patches/patch-bfd_netbsd-core.c
>

Good catch.

>>>>>
>>>>> Thanks,
>>>>> Christian
>>>>>
>>>>> On Fri, Jan 24, 2020 at 3:29 PM Kamil Rytarowski <n54@gmx.com> wrote:
>>>>>>
>>>>>> On 24.01.2020 15:18, cbiesinger@chromium.org wrote:
>>>>>>> From: Christian Biesinger <cbiesinger@google.com>
>>>>>>>
>>>>>>> Fixes the below compile error on ARM NetBSD 9.0_RC1 (the only version I
>>>>>>> tested). types.h does not define register_t by default.
>>>>>>>
>>>>>>> We already use this define elsewhere, notably in bsd-kvm.c.
>>>>>>>
>>>>>>> In file included from ../../gdb/arm-nbsd-nat.c:28:
>>>>>>> /usr/include/machine/frame.h:54:2: error: unknown type name 'register_t'; did you mean '__register_t'?
>>>>>>> register_t tf_spsr;
>>>>>>> ^
>>>>>>> /usr/include/machine/types.h:77:14: note: '__register_t' declared here
>>>>>>> typedef int __register_t;
>>>>>>> ^
>>>>>>>
>>>>>>> There are other compile errors that this does not fix.
>>>>>>>
>>>>>>> gdb/ChangeLog:
>>>>>>>
>>>>>>> 2020-01-24 Christian Biesinger <cbiesinger@google.com>
>>>>>>>
>>>>>>> * arm-nbsd-nat.c: Define _KMEMUSER to get the declaration of
>>>>>>> register_t.
>>>>>>>
>>>>>>> Change-Id: I82c21d38189ee59ea0af2538ba84b771d268722e
>>>>>>> ---
>>>>>>> gdb/arm-nbsd-nat.c | 2 ++
>>>>>>> 1 file changed, 2 insertions(+)
>>>>>>>
>>>>>>> diff --git a/gdb/arm-nbsd-nat.c b/gdb/arm-nbsd-nat.c
>>>>>>> index 00f919194b..4844b51a3c 100644
>>>>>>> --- a/gdb/arm-nbsd-nat.c
>>>>>>> +++ b/gdb/arm-nbsd-nat.c
>>>>>>> @@ -17,6 +17,8 @@
>>>>>>> You should have received a copy of the GNU General Public License
>>>>>>> along with this program. If not, see <http://www.gnu.org/licenses/>. */
>>>>>>>
>>>>>>> +/* We define this to get types like register_t. */
>>>>>>> +#define _KMEMUSER
>>>>>>> #include "defs.h"
>>>>>>> #include "gdbcore.h"
>>>>>>> #include "inferior.h"
>>>>>>>
>>>>>>
>>>>>> While gdb is the right user for _KMEMUSER, here we should probably go
>>>>>> for -D_KERNTYPES as it is the canonical symbol for register_t.
>>>>>>
>>>>
>>>>
>>
>>

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