public inbox for gdb@sourceware.org
 help / color / mirror / Atom feed
From: Pedro Alves <palves@redhat.com>
To: Michal Lesniewski <m.lesniewski@samsung.com>
Cc: gdb@sourceware.org
Subject: Re: Implementation of different software breakpoint kinds in gdb server
Date: Thu, 18 Oct 2012 10:08:00 -0000	[thread overview]
Message-ID: <507FD526.5080604@redhat.com> (raw)
In-Reply-To: <000001cdad12$1e2b1950$5a814bf0$%lesniewski@samsung.com>

On 10/18/2012 10:22 AM, Michal Lesniewski wrote:
> 
> I was wondering if anybody was already considering to extend the code in
> mem-break.c to add support for different kinds of breakpoints. 

Extending mem-break.c is not the big problem, IMO.  The RSP already supports
this, with the mode encoded in the "size" field of the z0 packet.

Offhand, the main issues with tracepoints on ARM are:

#1 - gdbserver needs to know how to step over the tracepoints, without gdb's intervention.

#2 - ARM can't hw single-step, so that needs to be done the hard way, with breakpoints
    (a.k.a., software single-step).
    All the logic to do that is in gdb.  This conflicts with #1.

So we'd need to teach gdbserver to software single-step.  Maybe it's possible
to tell offline all the possible destinations of an instruction, so we could still
leave that logic in gdb, but I suspect not.

I don't know whether the current kernel can already do all that for us? (perf,
uprobes, etc?)

-- 
Pedro Alves

  reply	other threads:[~2012-10-18 10:08 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-10-18  9:23 Michal Lesniewski
2012-10-18 10:08 ` Pedro Alves [this message]
2012-10-18 10:28   ` Yao Qi
2012-10-18 10:42     ` Pedro Alves
2012-10-18 11:44   ` Michal Lesniewski
2012-10-18 12:01     ` Pedro Alves
2012-10-19  0:31       ` John Gilmore
2012-10-19  8:51         ` Michal Lesniewski

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=507FD526.5080604@redhat.com \
    --to=palves@redhat.com \
    --cc=gdb@sourceware.org \
    --cc=m.lesniewski@samsung.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).