From: Joel Brobecker <brobecker@adacore.com>
To: Philippe Waroquiers <philippe.waroquiers@skynet.be>
Cc: Pedro Alves <palves@redhat.com>,
Jan Kratochvil <jan.kratochvil@redhat.com>,
gdb-patches@sourceware.org
Subject: Re: [patch] [i386] Put hlt at the ON_STACK breakpoint [Re: GDB 7.4.91 available for testing]
Date: Wed, 25 Jul 2012 21:27:00 -0000 [thread overview]
Message-ID: <20120725212653.GC2767@adacore.com> (raw)
In-Reply-To: <1343247870.2240.29.camel@soleil>
> The translated block is then continued <<< This is the critical info !!!
I am having trouble understanding why the translated block would
be continued in the case of an inferior function call, since
the code is not to be executed (thanks to resetting the PC to its
original value prior to the inferior function call when reaching
the Z0 breakpoint we inserted). But...
> So, if it is easy to change GDB to insert 0xcc (for x86 and amd84)
> and the equivalent breakpoint instr for mips32, then that avoids
> the kludgy patch in Valgrind, which is for sure fragile.
... if I still understand correctly, as long as we write a valid
instruction at the point where we place the infcall breakpoint,
we should be fine, right? Jan selected the hlt instruction, but
we could go with the breakpoint trap instruction as well (0xcc),
which I think should be simpler to generalize in the future.
It should not matter which instruction is chosen as long as it
fits the available space, since that instruction will never be
executed (thanks to the Z0 packet introducing an official breakpoint
there).
--
Joel
next prev parent reply other threads:[~2012-07-25 21:27 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20120718163413.GA17548@adacore.com>
[not found] ` <1342739016.2220.32.camel@soleil>
[not found] ` <20120720071158.GA7053@host2.jankratochvil.net>
[not found] ` <1342817409.2149.41.camel@soleil>
[not found] ` <20120722173053.GA22036@host2.jankratochvil.net>
[not found] ` <1342983655.2301.55.camel@soleil>
2012-07-23 7:22 ` Jan Kratochvil
2012-07-23 16:00 ` Joel Brobecker
2012-07-23 16:36 ` Jan Kratochvil
2012-07-23 20:07 ` Philippe Waroquiers
2012-07-23 20:16 ` Jan Kratochvil
2012-07-23 20:37 ` Philippe Waroquiers
2012-07-25 14:49 ` Joel Brobecker
2012-07-25 20:04 ` Philippe Waroquiers
2012-07-25 20:11 ` Jan Kratochvil
2012-07-25 20:39 ` Philippe Waroquiers
2012-07-25 14:59 ` Pedro Alves
2012-07-25 20:24 ` Philippe Waroquiers
2012-07-25 21:27 ` Joel Brobecker [this message]
2012-07-25 21:46 ` Philippe Waroquiers
2012-07-25 22:39 ` Joel Brobecker
2012-07-26 21:24 ` [patchv2] Write bpt at the ON_STACK bpt address Jan Kratochvil
2012-07-26 21:50 ` Philippe Waroquiers
2012-07-27 18:47 ` Jan Kratochvil
2012-07-28 7:28 ` Eli Zaretskii
2012-07-28 7:42 ` Jan Kratochvil
2012-07-31 7:37 ` [commit+7.5] " Jan Kratochvil
2012-08-01 9:08 ` [commit#2+7.5] testsuite: valgrind-infcall.exp UNSUPPORTED update [Re: [commit+7.5] [patchv2] Write bpt at the ON_STACK bpt address] Jan Kratochvil
2012-08-02 22:49 ` [commit+7.5] [patchv2] Write bpt at the ON_STACK bpt address Edjunior Barbosa Machado
2012-08-02 23:09 ` Sergio Durigan Junior
2012-08-03 0:15 ` Edjunior Barbosa Machado
2012-08-03 11:23 ` Jan Kratochvil
2012-08-03 12:09 ` Edjunior Barbosa Machado
2012-08-03 1:00 ` Pedro Alves
2012-08-03 1:48 ` Sergio Durigan Junior
2012-08-03 2:30 ` Edjunior Barbosa Machado
2012-08-03 21:45 ` Philippe Waroquiers
2012-08-03 14:23 ` Tom Tromey
2012-08-03 14:31 ` Jan Kratochvil
2012-08-03 15:02 ` Edjunior Barbosa Machado
2012-08-03 15:08 ` Jan Kratochvil
2012-08-03 16:43 ` Edjunior Barbosa Machado
2012-08-03 16:46 ` Jan Kratochvil
2012-08-03 18:00 ` Edjunior Barbosa Machado
2012-08-03 20:23 ` Jan Kratochvil
2012-08-03 21:46 ` Edjunior Barbosa Machado
2012-08-06 18:40 ` Tom Tromey
2012-07-31 7:40 ` [commit] valgrind-db-attach.exp: Do not run in remote mode [Re: [patchv2] Write bpt at the ON_STACK bpt address] Jan Kratochvil
2012-07-26 23:14 ` [patchv2] Write bpt at the ON_STACK bpt address Maciej W. Rozycki
2012-07-27 16:02 ` Jan Kratochvil
2012-07-28 0:10 ` Maciej W. Rozycki
2012-07-28 6:06 ` Jan Kratochvil
2012-07-30 18:09 ` Maciej W. Rozycki
2012-07-26 23:15 ` Philippe Waroquiers
2012-07-27 16:03 ` Jan Kratochvil
2012-07-27 15:21 ` Pedro Alves
2012-07-26 21:56 ` [patch] [i386] Put hlt at the ON_STACK breakpoint [Re: GDB 7.4.91 available for testing] Philippe Waroquiers
2012-07-26 22:41 ` Philippe Waroquiers
2012-07-26 5:13 ` Jan Kratochvil
2012-07-26 12:48 ` Pedro Alves
2012-07-26 22:21 ` Philippe Waroquiers
2012-07-27 14:59 ` Pedro Alves
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