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From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
To: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Oleg Nesterov <oleg@redhat.com>, Ingo Molnar <mingo@elte.hu>,
	Andrew Morton <akpm@linux-foundation.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Linux-mm <linux-mm@kvack.org>, Andi Kleen <andi@firstfloor.org>,
	Christoph Hellwig <hch@infradead.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Roland McGrath <roland@hack.frob.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
	Arnaldo Carvalho de Melo <acme@infradead.org>,
	Anton Arapov <anton@redhat.com>,
	Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
	Jim Keniston <jkenisto@linux.vnet.ibm.com>,
	Stephen Rothwell <sfr@canb.auug.org.au>
Subject: Re: [PATCH v10 3.3-rc2 1/9] uprobes: Install and remove breakpoints.
Date: Wed, 8 Feb 2012 15:10:09 +0530	[thread overview]
Message-ID: <20120208094009.GB24443@linux.vnet.ibm.com> (raw)
In-Reply-To: <CAK1hOcOd3hd31vZYw1yAVGK=gMV=vQotL1mRZkVgM=7M8mbMyw@mail.gmail.com>

* Denys Vlasenko <vda.linux@googlemail.com> [2012-02-08 10:40:30]:

> On Tue, Feb 7, 2012 at 6:17 PM, Srikar Dronamraju
> <srikar@linux.vnet.ibm.com> wrote:
> > Changelog: (Since v10): Add code to clear REX.B prefix pointed out by Denys Vlasenko
> > and fix suggested by Masami Hiramatsu.
> ...
> > +       /*
> > +        * Point cursor at the modrm byte.  The next 4 bytes are the
> > +        * displacement.  Beyond the displacement, for some instructions,
> > +        * is the immediate operand.
> > +        */
> > +       cursor = uprobe->insn + insn_offset_modrm(insn);
> > +       insn_get_length(insn);
> > +       if (insn->rex_prefix.nbytes)
> > +               *cursor &= 0xfe;        /* Clearing REX.B bit */
> 
> It looks like cursor points to mod/reg/rm byte, not rex byte.
> Comment above says it too. You seem to be clearing a bit
> in a wrong byte. I think it should be


Oh okay, Will correct this and send out a new patch.


> 
>         /* Clear REX.b bit (extension of MODRM.rm field):
>          * we want to encode rax/rcx, not r8/r9.
>          */
>         if (insn->rex_prefix.nbytes)
>                 insn->rex_prefix.bytes[0] &= 0xfe;

-- 
Thanks and Regards
Srikar

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  reply	other threads:[~2012-02-08  9:52 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-02 14:18 [PATCH v10 3.3-rc2 0/9] Uprobes patchset with perf probe support Srikar Dronamraju
2012-02-02 14:18 ` [PATCH v10 3.3-rc2 1/9] uprobes: Install and remove breakpoints Srikar Dronamraju
2012-02-03 12:01   ` Masami Hiramatsu
2012-02-07 17:17   ` Srikar Dronamraju
2012-02-08  9:40     ` Denys Vlasenko
2012-02-08  9:40       ` Srikar Dronamraju [this message]
2012-02-09  1:27       ` Masami Hiramatsu
2012-02-09  6:37         ` Srikar Dronamraju
2012-02-09  7:53           ` Ingo Molnar
2012-02-09  8:14             ` Srikar Dronamraju
2012-02-09  8:17           ` Masami Hiramatsu
2012-02-09  8:27             ` Srikar Dronamraju
2012-02-08 14:08     ` Srikar Dronamraju
2012-02-09  9:26       ` [PATCH v10 take 3 " Srikar Dronamraju
2012-02-17  9:58         ` [tip:perf/uprobes] uprobes, mm, x86: Add the ability to install and remove uprobes breakpoints tip-bot for Srikar Dronamraju
2012-05-21 21:37           ` Andrew Morton
2012-05-21 22:00             ` Linus Torvalds
2012-05-21 22:13               ` Andrew Morton
2012-05-22  1:16                 ` Stephen Rothwell
2012-05-22  2:27                   ` Andrew Morton
2012-05-22  6:50                     ` Stephen Rothwell
2012-05-23  0:37                 ` Stephen Rothwell
2012-05-22  1:10               ` Stephen Rothwell
2012-05-22  6:01               ` Srikar Dronamraju
2012-05-22  8:05             ` Srikar Dronamraju
2012-02-02 14:19 ` [PATCH v10 3.3-rc2 2/9] uprobes: handle breakpoint and signal step exception Srikar Dronamraju
2012-02-02 14:19 ` [PATCH v10 3.3-rc2 3/9] uprobes: slot allocation Srikar Dronamraju
2012-02-02 14:19 ` [PATCH v10 3.3-rc2 4/9] uprobes: counter to optimize probe hits Srikar Dronamraju
2012-02-02 14:19 ` [PATCH v10 3.3-rc2 5/9] tracing: modify is_delete, is_return from ints to bool Srikar Dronamraju
2012-02-02 14:20 ` [PATCH v10 3.3-rc2 6/9] tracing: Extract out common code for kprobes/uprobes traceevents Srikar Dronamraju
2012-02-02 14:20 ` [PATCH v10 3.3-rc2 7/9] tracing: uprobes trace_event interface Srikar Dronamraju
2012-02-02 14:20 ` [PATCH v10 3.3-rc2 8/9] perf: rename target_module to target Srikar Dronamraju
2012-02-07 19:33   ` [tip:perf/core] perf probe: Rename " tip-bot for Srikar Dronamraju
2012-02-02 14:20 ` [PATCH v10 3.3-rc2 9/9] perf: perf interface for uprobes Srikar Dronamraju

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