From: Philippe Waroquiers <philippe.waroquiers@skynet.be>
To: Jan Kratochvil <jan.kratochvil@redhat.com>
Cc: Joel Brobecker <brobecker@adacore.com>,
gdb-patches@sourceware.org, Pedro Alves <palves@redhat.com>
Subject: Re: [patch] [i386] Put hlt at the ON_STACK breakpoint [Re: GDB 7.4.91 available for testing]
Date: Wed, 25 Jul 2012 20:39:00 -0000 [thread overview]
Message-ID: <1343248757.2240.41.camel@soleil> (raw)
In-Reply-To: <20120725201107.GA32326@host2.jankratochvil.net>
On Wed, 2012-07-25 at 22:11 +0200, Jan Kratochvil wrote:
> On Wed, 25 Jul 2012 22:04:01 +0200, Philippe Waroquiers wrote:
> > IIUC, Jan's patch was to have GDB storing a hlt after the place
> > where GDBSERVER will put 0xCC.
>
> Not after, all the storage happens for the same byte.
Oops, I misunderstood that.
>
> hlt is stored there by memory write, int3 is stored there by Z0.
>
>
> > What Valgrind needs is to have GDB storing the 0xCC
> > (the hlt will then have no positive nor negative impact on Valgrind).
>
> I will put 0xcc == int3 there although I believe valgrind could decode hlt (or
> even nop) the same way.
I have not found the decoding of the hlt instruction in Valgrind, so
I suspect it might not be supported.
Any valid instruction that will terminate a "Valgrind block" will be ok
there. For sure, the 0xcc is ok. There are other instructions which also
ensures Valgrind stops translating the block (e.g. others "int"
instructions). I think "nop" does not stop the block translation.
So, inserting 0xcc looks more straightforward/natural/safer.
Philippe
next prev parent reply other threads:[~2012-07-25 20:39 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 [this message]
2012-07-25 14:59 ` Pedro Alves
2012-07-25 20:24 ` Philippe Waroquiers
2012-07-25 21:27 ` Joel Brobecker
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
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=1343248757.2240.41.camel@soleil \
--to=philippe.waroquiers@skynet.be \
--cc=brobecker@adacore.com \
--cc=gdb-patches@sourceware.org \
--cc=jan.kratochvil@redhat.com \
--cc=palves@redhat.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