From: Uros Bizjak <ubizjak@gmail.com>
To: Simon Marchi <simon.marchi@ericsson.com>
Cc: gdb-patches@sourceware.org,
Tobias Klausmann <klausman@schwarzvogel.de>,
rth@twiddle.net
Subject: Re: [PATCH]: Fix PR19061, gdb hangs/spins-on-cpu when debugging any program on Alpha
Date: Wed, 30 May 2018 18:49:00 -0000 [thread overview]
Message-ID: <CAFULd4b+d5y8NtTei+LhLxC6293aGnji=wG+HasXCc=4Wg61hw@mail.gmail.com> (raw)
In-Reply-To: <56293ba8-f95b-5da1-af14-7500a0f8f892@ericsson.com>
On Wed, May 30, 2018 at 4:53 PM, Simon Marchi <simon.marchi@ericsson.com> wrote:
> On 2017-12-15 07:11 AM, Uros Bizjak wrote:
>> Hello!
>>
>> Attached patch fixes PR19061, where gdb hangs/spins-on-cpu when
>> debugging any program on Alpha. The patch is effectively a forward
>> port of Richard's patch from the Comment #5 of the PR [1].
>>
>>
>> 2017-12-15 Uros Bizjak <ubizjak@gmail.com>
>> Richard Henderson <rth@redhat.com>
>>
>> PR gdb/19061
>> * alpha-tdep.c (alpha_software_single_step): Call
>> alpha_deal_with_atomic_sequence here.
>> (set_gdbarch_software_single_step): Set to alpha_software_single_step.
>> * nat/linux-ptrace.h [__alpha__]: Define GDB_ARCH_IS_TRAP_BRKPT
>> and GDB_ARCH_IS_TRAP_HWBKPT.
>>
>> Patch was tested on alphaev68-linux-gnu, also tested with gcc's
>> testsuite, where it fixed all hangs in guality.exp and
>> simulate-thread.exp testcases.
>>
>> Please note that I have no commit access, so if approved, please
>> commit the patch to the source repository for me. I also have
>> functionally equivalent patch for gdb-8 branch which I plan to submit
>> later.
>>
>> [1] https://sourceware.org/bugzilla/show_bug.cgi?id=19061#c5
>>
>> Uros.
>>
>
> Hi Uros and Richard,
>
> I would need your input. Using this cross-compiler:
>
> alphaev67-unknown-linux-gnu-gcc (crosstool-NG crosstool-ng-1.22.0-677-ga3dd55b9) 6.3.0
> Copyright (C) 2016 Free Software Foundation, Inc.
> This is free software; see the source for copying conditions. There is NO
> warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
>
> I get this error:
>
> CXX linux-nat.o
> /home/simark/src/binutils-gdb/gdb/linux-nat.c: In function 'void save_stop_reason(lwp_info*)':
> /home/simark/src/binutils-gdb/gdb/linux-nat.c:2718:9: error: duplicated 'if' condition [-Werror=duplicated-cond]
> else if (GDB_ARCH_IS_TRAP_HWBKPT (siginfo.si_code))
> ^~
> In file included from /home/simark/src/binutils-gdb/gdb/linux-nat.c:31:0:
> /home/simark/src/binutils-gdb/gdb/nat/linux-ptrace.h:173:41: note: previously used here
> # define GDB_ARCH_IS_TRAP_BRKPT(X) ((X) == TRAP_BRKPT)
> ~~~~~^~~~~~~~~~~~~~
> /home/simark/src/binutils-gdb/gdb/linux-nat.c:2709:13: note: in expansion of macro 'GDB_ARCH_IS_TRAP_BRKPT'
> else if (GDB_ARCH_IS_TRAP_BRKPT (siginfo.si_code))
> ^~~~~~~~~~~~~~~~~~~~~~
>
> Does Alpha even have hardware breakpoints? If not, I would suggest
> defining GDB_ARCH_IS_TRAP_HWBKPT to 0 for __alpha__. It would get
> rid of the error, and be more exact (no si_code can mean "hardware
> breakpoint" on alpha).
Richard said that:
The hardware does not, but the linux kernel pretends.
IIRC the number of round-trips and flushes is supposed
to be lower doing it from within the kernel.
BR,
Uros.
next prev parent reply other threads:[~2018-05-30 18:07 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-15 12:11 Uros Bizjak
2017-12-15 18:21 ` Pedro Alves
2017-12-17 18:11 ` Uros Bizjak
2017-12-17 19:14 ` Uros Bizjak
2018-01-03 16:02 ` Pedro Alves
2018-05-30 18:07 ` Simon Marchi
2018-05-30 18:49 ` Uros Bizjak [this message]
2018-05-30 19:04 ` Simon Marchi
2018-05-31 11:10 ` Uros Bizjak
2018-05-31 14:55 ` Simon Marchi
2018-05-31 16:18 ` Simon Marchi
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAFULd4b+d5y8NtTei+LhLxC6293aGnji=wG+HasXCc=4Wg61hw@mail.gmail.com' \
--to=ubizjak@gmail.com \
--cc=gdb-patches@sourceware.org \
--cc=klausman@schwarzvogel.de \
--cc=rth@twiddle.net \
--cc=simon.marchi@ericsson.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).