linux-kselftest.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: rostedt at goodmis.org (Steven Rostedt)
Subject: [RFC][PATCH 1/2] x86: Allow breakpoints to emulate call functions
Date: Mon, 6 May 2019 22:58:19 -0400	[thread overview]
Message-ID: <20190506225819.11756974@oasis.local.home> (raw)
In-Reply-To: <CAHk-=wjLXmOn=Cp=uOfO4gE01eN_-UcOUyrMTTw5-f_OfPO48Q@mail.gmail.com>

On Mon, 6 May 2019 19:22:06 -0700
Linus Torvalds <torvalds at linux-foundation.org> wrote:

> Notice? We'd not even have to look up any values.  We'd literally just
> do something like
> 
>         int offset = locked_atomic_read(ip+1);
>         return int3_emulate_call(ip, ip+5+offset);
> 
> and it would be *atomic* with respect to whatever other user that
> updates the instruction, as long as they update the offset with a
> "xchg" instruction.

Honestly, I'm not really sure what you are trying to do here.

Are you talking about making the update to the code in the int3
handler? And then just returning back to the regs->ip and executing the
new call (not really emulating).

-- Steve

WARNING: multiple messages have this Message-ID (diff)
From: rostedt@goodmis.org (Steven Rostedt)
Subject: [RFC][PATCH 1/2] x86: Allow breakpoints to emulate call functions
Date: Mon, 6 May 2019 22:58:19 -0400	[thread overview]
Message-ID: <20190506225819.11756974@oasis.local.home> (raw)
Message-ID: <20190507025819.WTH5swEDOS-HHksnp45-5s0imFkuBgmmPWe39fvqcro@z> (raw)
In-Reply-To: <CAHk-=wjLXmOn=Cp=uOfO4gE01eN_-UcOUyrMTTw5-f_OfPO48Q@mail.gmail.com>

On Mon, 6 May 2019 19:22:06 -0700
Linus Torvalds <torvalds@linux-foundation.org> wrote:

> Notice? We'd not even have to look up any values.  We'd literally just
> do something like
> 
>         int offset = locked_atomic_read(ip+1);
>         return int3_emulate_call(ip, ip+5+offset);
> 
> and it would be *atomic* with respect to whatever other user that
> updates the instruction, as long as they update the offset with a
> "xchg" instruction.

Honestly, I'm not really sure what you are trying to do here.

Are you talking about making the update to the code in the int3
handler? And then just returning back to the regs->ip and executing the
new call (not really emulating).

-- Steve

  parent reply	other threads:[~2019-05-07  2:58 UTC|newest]

Thread overview: 204+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20190501202830.347656894@goodmis.org>
2019-05-01 20:28 ` [RFC][PATCH 1/2] x86: Allow breakpoints to emulate call functions rostedt
2019-05-01 20:28   ` Steven Rostedt
2019-05-02  3:24   ` rostedt
2019-05-02  3:24     ` Steven Rostedt
2019-05-02 16:21     ` peterz
2019-05-02 16:21       ` Peter Zijlstra
2019-05-02 16:29       ` peterz
2019-05-02 16:29         ` Peter Zijlstra
2019-05-02 18:02       ` torvalds
2019-05-02 18:02         ` Linus Torvalds
2019-05-02 18:18         ` peterz
2019-05-02 18:18           ` Peter Zijlstra
2019-05-02 18:30           ` peterz
2019-05-02 18:30             ` Peter Zijlstra
2019-05-02 18:43           ` torvalds
2019-05-02 18:43             ` Linus Torvalds
2019-05-02 19:28             ` jikos
2019-05-02 19:28               ` Jiri Kosina
2019-05-02 20:25               ` luto
2019-05-02 20:25                 ` Andy Lutomirski
2019-05-02 20:21             ` peterz
2019-05-02 20:21               ` Peter Zijlstra
2019-05-02 20:49               ` torvalds
2019-05-02 20:49                 ` Linus Torvalds
2019-05-02 21:32                 ` peterz
2019-05-02 21:32                   ` Peter Zijlstra
2019-05-03 19:24                 ` rostedt
2019-05-03 19:24                   ` Steven Rostedt
2019-05-03 21:46                   ` torvalds
2019-05-03 21:46                     ` Linus Torvalds
2019-05-03 22:49                     ` rostedt
2019-05-03 22:49                       ` Steven Rostedt
2019-05-03 23:07                       ` torvalds
2019-05-03 23:07                         ` Linus Torvalds
2019-05-04  4:17                         ` rostedt
2019-05-04  4:17                           ` Steven Rostedt
     [not found]                           ` <CAHk-=wiuSFbv_rELND-BLWcP0GSZ0yF=xOAEcf61GE3bU9d=yg@mail.gmail.com>
2019-05-04 18:59                             ` torvalds
2019-05-04 18:59                               ` Linus Torvalds
2019-05-04 20:12                               ` luto
2019-05-04 20:12                                 ` Andy Lutomirski
2019-05-04 20:28                                 ` torvalds
2019-05-04 20:28                                   ` Linus Torvalds
2019-05-04 20:36                                 ` torvalds
2019-05-04 20:36                                   ` Linus Torvalds
2019-05-03 22:55                     ` luto
2019-05-03 22:55                       ` Andy Lutomirski
2019-05-03 23:16                       ` torvalds
2019-05-03 23:16                         ` Linus Torvalds
2019-05-03 23:32                         ` luto
2019-05-03 23:32                           ` Andy Lutomirski
2019-05-02 22:52               ` rostedt
2019-05-02 22:52                 ` Steven Rostedt
2019-05-02 23:31                 ` rostedt
2019-05-02 23:31                   ` Steven Rostedt
2019-05-02 23:50                   ` rostedt
2019-05-02 23:50                     ` Steven Rostedt
2019-05-03  1:51                     ` [RFC][PATCH 1/2 v2] " rostedt
2019-05-03  1:51                       ` Steven Rostedt
2019-05-03  9:29                     ` [RFC][PATCH 1/2] " peterz
2019-05-03  9:29                       ` Peter Zijlstra
2019-05-03 13:22                       ` rostedt
2019-05-03 13:22                         ` Steven Rostedt
2019-05-03 16:20                         ` luto
2019-05-03 16:20                           ` Andy Lutomirski
2019-05-03 16:31                           ` rostedt
2019-05-03 16:31                             ` Steven Rostedt
2019-05-03 16:35                             ` peterz
2019-05-03 16:35                               ` Peter Zijlstra
2019-05-03 16:44                               ` luto
2019-05-03 16:44                                 ` Andy Lutomirski
2019-05-03 16:49                                 ` rostedt
2019-05-03 16:49                                   ` Steven Rostedt
2019-05-03 16:32                           ` peterz
2019-05-03 16:32                             ` Peter Zijlstra
2019-05-03 18:57                           ` torvalds
2019-05-03 18:57                             ` Linus Torvalds
2019-05-06  8:19                             ` peterz
2019-05-06  8:19                               ` Peter Zijlstra
2019-05-06 13:56                               ` rostedt
2019-05-06 13:56                                 ` Steven Rostedt
2019-05-06 16:17                                 ` torvalds
2019-05-06 16:17                                   ` Linus Torvalds
2019-05-06 16:19                                   ` torvalds
2019-05-06 16:19                                     ` Linus Torvalds
2019-05-06 17:06                                   ` rostedt
2019-05-06 17:06                                     ` Steven Rostedt
2019-05-06 18:06                                     ` torvalds
2019-05-06 18:06                                       ` Linus Torvalds
2019-05-06 18:57                                       ` rostedt
2019-05-06 18:57                                         ` Steven Rostedt
2019-05-06 19:46                                         ` torvalds
2019-05-06 19:46                                           ` Linus Torvalds
2019-05-06 20:29                                           ` rostedt
2019-05-06 20:29                                             ` Steven Rostedt
2019-05-06 20:42                                             ` torvalds
2019-05-06 20:42                                               ` Linus Torvalds
2019-05-06 20:44                                               ` torvalds
2019-05-06 20:44                                                 ` Linus Torvalds
2019-05-06 21:45                                               ` rostedt
2019-05-06 21:45                                                 ` Steven Rostedt
2019-05-06 22:06                                                 ` torvalds
2019-05-06 22:06                                                   ` Linus Torvalds
2019-05-06 22:31                                                   ` torvalds
2019-05-06 22:31                                                     ` Linus Torvalds
2019-05-07  0:10                                                     ` rostedt
2019-05-07  0:10                                                       ` Steven Rostedt
2019-05-07  1:06                                                       ` torvalds
2019-05-07  1:06                                                         ` Linus Torvalds
2019-05-07  1:04                                                   ` rostedt
2019-05-07  1:04                                                     ` Steven Rostedt
2019-05-07  1:34                                                     ` rostedt
2019-05-07  1:34                                                       ` Steven Rostedt
2019-05-07  1:34                                                     ` torvalds
2019-05-07  1:34                                                       ` Linus Torvalds
2019-05-07  1:53                                                       ` rostedt
2019-05-07  1:53                                                         ` Steven Rostedt
2019-05-07  2:22                                                         ` torvalds
2019-05-07  2:22                                                           ` Linus Torvalds
2019-05-07  2:58                                                           ` rostedt [this message]
2019-05-07  2:58                                                             ` Steven Rostedt
2019-05-07  3:05                                                             ` torvalds
2019-05-07  3:05                                                               ` Linus Torvalds
2019-05-07  3:21                                                               ` rostedt
2019-05-07  3:21                                                                 ` Steven Rostedt
2019-05-07  3:28                                                                 ` torvalds
2019-05-07  3:28                                                                   ` Linus Torvalds
2019-05-07 14:54                                                                   ` torvalds
2019-05-07 14:54                                                                     ` Linus Torvalds
2019-05-07 15:12                                                                     ` rostedt
2019-05-07 15:12                                                                       ` Steven Rostedt
2019-05-07 15:25                                                                       ` rostedt
2019-05-07 15:25                                                                         ` Steven Rostedt
2019-05-07 16:25                                                                         ` rostedt
2019-05-07 16:25                                                                           ` Steven Rostedt
2019-05-07 15:31                                                                       ` torvalds
2019-05-07 15:31                                                                         ` Linus Torvalds
2019-05-07 15:45                                                                         ` rostedt
2019-05-07 15:45                                                                           ` Steven Rostedt
2019-05-07 16:34                                                                         ` peterz
2019-05-07 16:34                                                                           ` Peter Zijlstra
2019-05-07 17:08                                                                           ` torvalds
2019-05-07 17:08                                                                             ` Linus Torvalds
2019-05-07 17:21                                                                             ` jpoimboe
2019-05-07 17:21                                                                               ` Josh Poimboeuf
2019-05-07 21:24                                                                               ` rostedt
2019-05-07 21:24                                                                                 ` Steven Rostedt
2019-05-08  4:50                                                                                 ` torvalds
2019-05-08  4:50                                                                                   ` Linus Torvalds
2019-05-08 16:37                                                                                   ` rostedt
2019-05-08 16:37                                                                                     ` Steven Rostedt
2019-05-07 17:38                                                                             ` peterz
2019-05-07 17:38                                                                               ` Peter Zijlstra
2019-05-07  9:51                                                           ` peterz
2019-05-07  9:51                                                             ` Peter Zijlstra
2019-05-07 14:48                                                           ` luto
2019-05-07 14:48                                                             ` Andy Lutomirski
2019-05-07 14:57                                                             ` torvalds
2019-05-07 14:57                                                               ` Linus Torvalds
2019-05-07 14:13                                                 ` mhiramat
2019-05-07 14:13                                                   ` Masami Hiramatsu
2019-05-07 17:15                                                   ` mhiramat
2019-05-07 17:15                                                     ` Masami Hiramatsu
2019-05-06 14:22                               ` peterz
2019-05-06 14:22                                 ` Peter Zijlstra
2019-05-07  8:57                               ` peterz
2019-05-07  8:57                                 ` Peter Zijlstra
2019-05-07  9:18                                 ` David.Laight
2019-05-07  9:18                                   ` David Laight
2019-05-07 11:30                                   ` peterz
2019-05-07 11:30                                     ` Peter Zijlstra
2019-05-07 12:57                                     ` David.Laight
2019-05-07 12:57                                       ` David Laight
2019-05-07 13:14                                       ` rostedt
2019-05-07 13:14                                         ` Steven Rostedt
2019-05-07 14:50                                         ` David.Laight
2019-05-07 14:50                                           ` David Laight
2019-05-07 14:57                                           ` rostedt
2019-05-07 14:57                                             ` Steven Rostedt
2019-05-07 15:46                                             ` David.Laight
2019-05-07 15:46                                               ` David Laight
2019-05-07 13:32                                       ` peterz
2019-05-07 13:32                                         ` Peter Zijlstra
2019-05-07  9:27                                 ` peterz
2019-05-07  9:27                                   ` Peter Zijlstra
2019-05-07 12:27                                   ` rostedt
2019-05-07 12:27                                     ` Steven Rostedt
2019-05-07 12:41                                     ` peterz
2019-05-07 12:41                                       ` Peter Zijlstra
2019-05-07 12:54                                       ` rostedt
2019-05-07 12:54                                         ` Steven Rostedt
2019-05-07 17:22                                         ` masami.hiramatsu
2019-05-07 17:22                                           ` Masami Hiramatsu
2019-05-07 14:28                                 ` peterz
2019-05-07 14:28                                   ` Peter Zijlstra
2019-05-02 20:48         ` rostedt
2019-05-02 20:48           ` Steven Rostedt
2019-05-06 15:14         ` jpoimboe
2019-05-06 15:14           ` Josh Poimboeuf
2019-05-01 20:28 ` [RFC][PATCH 2/2] ftrace/x86: Emulate call function while updating in breakpoint handler rostedt
2019-05-01 20:28   ` Steven Rostedt
2019-05-03 10:22 ` [RFC][PATCH 1.5/2] x86: Add int3_emulate_call() selftest peterz
2019-05-03 10:22   ` Peter Zijlstra
2019-05-03 18:46   ` rostedt
2019-05-03 18:46     ` Steven Rostedt

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=20190506225819.11756974@oasis.local.home \
    --to=linux-kselftest@vger.kernel.org \
    /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 NNTP newsgroup(s).