From: Pedro Alves <palves@redhat.com>
To: gdb-patches@sourceware.org
Subject: Re: [PATCH v2 03/23] PR13858 - Can't do displaced stepping with no symbols
Date: Thu, 09 Apr 2015 12:46:00 -0000 [thread overview]
Message-ID: <5526748D.5060400@redhat.com> (raw)
In-Reply-To: <1428410990-28560-4-git-send-email-palves@redhat.com>
On 04/07/2015 01:49 PM, Pedro Alves wrote:
> Running break-interp.exp with the target always in non-stop mode trips
> on PR13858, as enabling non-stop also enables displaced stepping.
>
> The problem is that when GDB doesn't know where the entry point is, it
> doesn't know where to put the displaced stepping scratch pad. The
> test added by this commit exercises this. Without the fix, we get:
>
> (gdb) PASS: gdb.base/step-over-no-symbols.exp: displaced=on: break *$pc
> set displaced-stepping on
> (gdb) PASS: gdb.base/step-over-no-symbols.exp: displaced=on: set displaced-stepping on
> stepi
> 0x00000000004005be in ?? ()
> Entry point address is not known.
> (gdb) PASS: gdb.base/step-over-no-symbols.exp: displaced=on: stepi
> p /x $pc
> $2 = 0x4005be
> (gdb) PASS: gdb.base/step-over-no-symbols.exp: displaced=on: get after PC
> FAIL: gdb.base/step-over-no-symbols.exp: displaced=on: advanced
>
> The fix is to fall back to stepping over the breakpoint in-line if we
> don't know where the entry point address is.
>
> This is enough to fix all-stop + "set displaced on". For non-stop,
> we'll need to teach core gdb to pause all threads to be able to start
> the in-line step-over (because then we need to remove the breakpoint
> from the target temporarily).
Hmm, actually not all targets get the entry point from symbols -- when
Cell debugging is enabled, PPC gets the entry point from AT_ENTRY from
the auxv... We should probably make that the default on GNU/Linux.
I just tried that now on x86-64 and it worked fine.
Thanks,
Pedro Alves
next prev parent reply other threads:[~2015-04-09 12:46 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-07 12:49 [PATCH v2 00/23] All-stop on top of non-stop Pedro Alves
2015-04-07 12:50 ` [PATCH v2 15/23] Implement all-stop on top of a target running non-stop mode Pedro Alves
2015-04-07 13:36 ` Eli Zaretskii
2015-04-08 9:34 ` Yao Qi
2015-04-08 9:53 ` Pedro Alves
2015-04-08 11:08 ` Pedro Alves
2015-04-08 19:35 ` Pedro Alves
2015-04-08 19:41 ` Pedro Alves
2015-04-07 12:50 ` [PATCH v2 16/23] Fix signal-while-stepping-over-bp-other-thread.exp on targets always in non-stop Pedro Alves
2015-04-07 12:50 ` [PATCH v2 02/23] Fix and test "checkpoint" in non-stop mode Pedro Alves
2015-04-07 12:50 ` [PATCH v2 20/23] PPC64: symbol-file + exec-file results in broken displaced stepping Pedro Alves
2015-04-07 12:50 ` [PATCH v2 12/23] Misc switch_back_to_stepped_thread cleanups Pedro Alves
2015-04-07 12:50 ` [PATCH v2 21/23] PPC64: Fix gdb.arch/ppc64-atomic-inst.exp with displaced stepping Pedro Alves
2015-04-07 12:50 ` [PATCH v2 04/23] Change adjust_pc_after_break's prototype Pedro Alves
2015-04-07 12:50 ` [PATCH v2 11/23] Use keep_going in proceed and start_step_over too Pedro Alves
2015-04-07 12:50 ` [PATCH v2 22/23] S/390: displaced stepping and PC-relative RIL-b/RIL-c instructions Pedro Alves
2015-04-07 12:50 ` [PATCH v2 10/23] PPC64: Fix step-over-trips-on-watchpoint.exp with displaced stepping on Pedro Alves
2015-04-07 12:50 ` [PATCH v2 05/23] remote.c/all-stop: Implement TARGET_WAITKIND_NO_RESUMED and TARGET_WNOHANG Pedro Alves
2015-04-07 12:50 ` [PATCH v2 09/23] Make gdb.threads/step-over-trips-on-watchpoint.exp effective on !x86 Pedro Alves
2015-04-07 12:50 ` [PATCH v2 23/23] native Linux: enable always non-stop by default Pedro Alves
2015-04-07 12:50 ` [PATCH v2 19/23] Disable displaced stepping if trying it fails Pedro Alves
2015-04-07 12:50 ` [PATCH v2 03/23] PR13858 - Can't do displaced stepping with no symbols Pedro Alves
2015-04-09 12:46 ` Pedro Alves [this message]
2015-04-07 12:50 ` [PATCH v2 01/23] Fix gdb.base/sigstep.exp with displaced stepping on software single-step targets Pedro Alves
2015-04-10 9:56 ` Pedro Alves
2015-04-07 12:55 ` [PATCH v2 17/23] Fix interrupt-noterm.exp on targets always in non-stop Pedro Alves
2015-04-07 12:57 ` [PATCH v2 08/23] Test step-over-{lands-on-breakpoint|trips-on-watchpoint}.exp with displaced stepping Pedro Alves
2015-04-10 14:54 ` Pedro Alves
2015-04-07 12:59 ` [PATCH v2 07/23] Embed the pending step-over chain in thread_info objects Pedro Alves
2015-04-07 12:59 ` [PATCH v2 13/23] Factor out code to re-resume stepped thread Pedro Alves
2015-04-07 12:59 ` [PATCH v2 14/23] Teach non-stop to do in-line step-overs (stop all, step, restart) Pedro Alves
2015-04-07 13:30 ` [PATCH v2 18/23] Fix step-over-{trips-on-watchpoint|lands-on-breakpoint}.exp race Pedro Alves
2015-04-07 13:30 ` [PATCH v2 06/23] Make thread_still_needs_step_over consider stepping_over_watchpoint too Pedro Alves
2015-04-08 9:28 ` Yao Qi
2015-04-13 10:47 ` Pedro Alves
2015-04-08 9:45 ` [PATCH v2 00/23] All-stop on top of non-stop Yao Qi
2015-04-08 10:17 ` Pedro Alves
2015-04-08 10:30 ` Pedro Alves
2015-04-10 8:41 ` Yao Qi
2015-04-10 8:50 ` Pedro Alves
2015-04-10 8:22 ` Yao Qi
2015-04-10 8:34 ` Pedro Alves
2015-04-10 9:26 ` Yao Qi
2015-04-13 15:28 ` Pedro Alves
2015-04-13 16:16 ` Yao Qi
2015-04-13 16:23 ` Pedro Alves
2015-04-13 16:23 ` Pedro Alves
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