From: Steven Rostedt <rostedt@goodmis.org>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Nicolai Stange <nstange@suse.de>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, Josh Poimboeuf <jpoimboe@redhat.com>,
Jiri Kosina <jikos@kernel.org>, Miroslav Benes <mbenes@suse.cz>,
Petr Mladek <pmladek@suse.com>,
Joe Lawrence <joe.lawrence@redhat.com>,
Shuah Khan <shuah@kernel.org>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Tim Chen <tim.c.chen@linux.intel.com>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Mimi Zohar <zohar@linux.ibm.com>, Juergen Gross <jgross@suse.com>,
Nick Desaulniers <ndesaulniers@google.com>,
Nayna Jain <nayna@linux.ibm.com>,
Masahiro Yamada <yamada.masahiro@socionext.com>,
Andy Lutomirski <luto@kernel.org>, Joerg Roedel <jroedel@suse.de>,
linux-kernel@vger.kernel.org, live-patching@vger.kernel.org,
linux-kselftest@vger.kernel.org
Subject: Re: [PATCH 1/4] x86/thread_info: introduce ->ftrace_int3_stack member
Date: Sun, 28 Apr 2019 15:43:45 -0400 [thread overview]
Message-ID: <20190428154345.789635b3@oasis.local.home> (raw)
In-Reply-To: <D5735AF7-D603-4B20-A3EE-B519044D1E5D@amacapital.net>
On Sun, 28 Apr 2019 11:08:34 -0700
Andy Lutomirski <luto@amacapital.net> wrote:
> >
> > Perhaps adding another slot into pt_regs that gets used by int3 to
> > store a slot to emulate a call on return?
> >
> >
>
> That’s not totally nuts, although finding pt_regs isn’t entirely trivial.
I meant on the int3 handler (which stores the pt_regs).
>
> I still think I prefer an approach where we just emulate the call directly.
Then, on the return of int3, if there's anything in that slot, then we
could possibly shift the exception handler frame (that was added by the
hardware), insert the slot data into the top of the stack, and then
call iret (which the int3 handler, would add the return ip to be the
function being called), which would in essence emulate the call directly.
I believe the complexity comes from the exception frame added by the
hardware is where we need to put the return of the call for the
emulation.
-- Steve
WARNING: multiple messages have this Message-ID (diff)
From: rostedt at goodmis.org (Steven Rostedt)
Subject: [PATCH 1/4] x86/thread_info: introduce ->ftrace_int3_stack member
Date: Sun, 28 Apr 2019 15:43:45 -0400 [thread overview]
Message-ID: <20190428154345.789635b3@oasis.local.home> (raw)
In-Reply-To: <D5735AF7-D603-4B20-A3EE-B519044D1E5D@amacapital.net>
On Sun, 28 Apr 2019 11:08:34 -0700
Andy Lutomirski <luto at amacapital.net> wrote:
> >
> > Perhaps adding another slot into pt_regs that gets used by int3 to
> > store a slot to emulate a call on return?
> >
> >
>
> That’s not totally nuts, although finding pt_regs isn’t entirely trivial.
I meant on the int3 handler (which stores the pt_regs).
>
> I still think I prefer an approach where we just emulate the call directly.
Then, on the return of int3, if there's anything in that slot, then we
could possibly shift the exception handler frame (that was added by the
hardware), insert the slot data into the top of the stack, and then
call iret (which the int3 handler, would add the return ip to be the
function being called), which would in essence emulate the call directly.
I believe the complexity comes from the exception frame added by the
hardware is where we need to put the return of the call for the
emulation.
-- Steve
WARNING: multiple messages have this Message-ID (diff)
From: rostedt@goodmis.org (Steven Rostedt)
Subject: [PATCH 1/4] x86/thread_info: introduce ->ftrace_int3_stack member
Date: Sun, 28 Apr 2019 15:43:45 -0400 [thread overview]
Message-ID: <20190428154345.789635b3@oasis.local.home> (raw)
Message-ID: <20190428194345.kG1NxIklMDXB6GofFg5NYxOS5HeZdZfhIh-CY94K3q4@z> (raw)
In-Reply-To: <D5735AF7-D603-4B20-A3EE-B519044D1E5D@amacapital.net>
On Sun, 28 Apr 2019 11:08:34 -0700
Andy Lutomirski <luto@amacapital.net> wrote:
> >
> > Perhaps adding another slot into pt_regs that gets used by int3 to
> > store a slot to emulate a call on return?
> >
> >
>
> That’s not totally nuts, although finding pt_regs isn’t entirely trivial.
I meant on the int3 handler (which stores the pt_regs).
>
> I still think I prefer an approach where we just emulate the call directly.
Then, on the return of int3, if there's anything in that slot, then we
could possibly shift the exception handler frame (that was added by the
hardware), insert the slot data into the top of the stack, and then
call iret (which the int3 handler, would add the return ip to be the
function being called), which would in essence emulate the call directly.
I believe the complexity comes from the exception frame added by the
hardware is where we need to put the return of the call for the
emulation.
-- Steve
next prev parent reply other threads:[~2019-04-28 19:43 UTC|newest]
Thread overview: 192+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-27 10:06 [PATCH 0/4] x86/ftrace: make ftrace_int3_handler() not to skip fops invocation Nicolai Stange
2019-04-27 10:06 ` Nicolai Stange
2019-04-27 10:06 ` nstange
2019-04-27 10:06 ` [PATCH 1/4] x86/thread_info: introduce ->ftrace_int3_stack member Nicolai Stange
2019-04-27 10:06 ` Nicolai Stange
2019-04-27 10:06 ` nstange
2019-04-28 17:41 ` Andy Lutomirski
2019-04-28 17:41 ` Andy Lutomirski
2019-04-28 17:41 ` luto
2019-04-28 17:51 ` Steven Rostedt
2019-04-28 17:51 ` Steven Rostedt
2019-04-28 17:51 ` rostedt
2019-04-28 18:08 ` Andy Lutomirski
2019-04-28 18:08 ` Andy Lutomirski
2019-04-28 18:08 ` luto
2019-04-28 19:43 ` Steven Rostedt [this message]
2019-04-28 19:43 ` Steven Rostedt
2019-04-28 19:43 ` rostedt
2019-04-28 20:56 ` Andy Lutomirski
2019-04-28 20:56 ` Andy Lutomirski
2019-04-28 20:56 ` luto
2019-04-28 21:22 ` Nicolai Stange
2019-04-28 21:22 ` Nicolai Stange
2019-04-28 21:22 ` nstange
2019-04-28 23:27 ` Andy Lutomirski
2019-04-28 23:27 ` Andy Lutomirski
2019-04-28 23:27 ` luto
2019-04-27 10:06 ` [PATCH 2/4] ftrace: drop 'static' qualifier from ftrace_ops_list_func() Nicolai Stange
2019-04-27 10:06 ` Nicolai Stange
2019-04-27 10:06 ` nstange
2019-04-27 10:06 ` [PATCH 3/4] x86/ftrace: make ftrace_int3_handler() not to skip fops invocation Nicolai Stange
2019-04-27 10:06 ` Nicolai Stange
2019-04-27 10:06 ` nstange
2019-04-27 10:26 ` Peter Zijlstra
2019-04-27 10:26 ` Peter Zijlstra
2019-04-27 10:26 ` peterz
2019-04-28 17:38 ` Steven Rostedt
2019-04-28 17:38 ` Steven Rostedt
2019-04-28 17:38 ` rostedt
2019-04-29 18:06 ` Linus Torvalds
2019-04-29 18:06 ` Linus Torvalds
2019-04-29 18:06 ` torvalds
2019-04-29 18:22 ` Linus Torvalds
2019-04-29 18:22 ` Linus Torvalds
2019-04-29 18:22 ` torvalds
2019-04-29 18:42 ` Andy Lutomirski
2019-04-29 18:42 ` Andy Lutomirski
2019-04-29 18:42 ` luto
[not found] ` <CAHk-=whtt4K2f0KPtG-4Pykh3FK8UBOjD8jhXCUKB5nWDj_YRA@mail.gmail.com>
2019-04-29 18:56 ` Andy Lutomirski
2019-04-29 18:56 ` Andy Lutomirski
2019-04-29 18:56 ` luto
[not found] ` <CAHk-=wgewK4eFhF3=0RNtk1KQjMANFH6oDE=8m=84RExn2gxhw@mail.gmail.com>
[not found] ` <CAHk-=whay7eN6+2gZjY-ybRbkbcqAmgrLwwszzHx8ws3c=S-MA@mail.gmail.com>
2019-04-29 19:24 ` Andy Lutomirski
2019-04-29 19:24 ` Andy Lutomirski
2019-04-29 19:24 ` luto
2019-04-29 20:07 ` Linus Torvalds
2019-04-29 20:07 ` Linus Torvalds
2019-04-29 20:07 ` torvalds
2019-04-30 13:56 ` Peter Zijlstra
2019-04-30 13:56 ` Peter Zijlstra
2019-04-30 13:56 ` peterz
2019-04-30 16:06 ` Linus Torvalds
2019-04-30 16:06 ` Linus Torvalds
2019-04-30 16:06 ` torvalds
2019-04-30 16:33 ` Andy Lutomirski
2019-04-30 16:33 ` Andy Lutomirski
2019-04-30 16:33 ` luto
2019-04-30 17:03 ` Steven Rostedt
2019-04-30 17:03 ` Steven Rostedt
2019-04-30 17:03 ` rostedt
2019-04-30 17:20 ` Steven Rostedt
2019-04-30 17:20 ` Steven Rostedt
2019-04-30 17:20 ` rostedt
2019-04-30 17:49 ` [RFC][PATCH] ftrace/x86: Emulate call function while updating in breakpoint handler Steven Rostedt
2019-04-30 17:49 ` Steven Rostedt
2019-04-30 17:49 ` rostedt
2019-04-30 18:33 ` Linus Torvalds
2019-04-30 18:33 ` Linus Torvalds
2019-04-30 18:33 ` torvalds
2019-04-30 19:00 ` Steven Rostedt
2019-04-30 19:00 ` Steven Rostedt
2019-04-30 19:00 ` rostedt
2019-04-30 21:08 ` Steven Rostedt
2019-04-30 21:08 ` Steven Rostedt
2019-04-30 21:08 ` rostedt
2019-05-01 13:11 ` Peter Zijlstra
2019-05-01 13:11 ` Peter Zijlstra
2019-05-01 13:11 ` peterz
2019-05-01 18:58 ` Steven Rostedt
2019-05-01 18:58 ` Steven Rostedt
2019-05-01 18:58 ` rostedt
2019-05-01 19:03 ` Peter Zijlstra
2019-05-01 19:03 ` Peter Zijlstra
2019-05-01 19:03 ` peterz
2019-05-01 19:03 ` Linus Torvalds
2019-05-01 19:03 ` Linus Torvalds
2019-05-01 19:03 ` torvalds
2019-05-01 19:13 ` Peter Zijlstra
2019-05-01 19:13 ` Peter Zijlstra
2019-05-01 19:13 ` peterz
2019-05-01 19:13 ` Steven Rostedt
2019-05-01 19:13 ` Steven Rostedt
2019-05-01 19:13 ` rostedt
2019-05-01 19:33 ` Jiri Kosina
2019-05-01 19:33 ` Jiri Kosina
2019-05-01 19:33 ` jikos
2019-05-01 19:41 ` Peter Zijlstra
2019-05-01 19:41 ` Peter Zijlstra
2019-05-01 19:41 ` peterz
2019-04-30 21:53 ` [RFC][PATCH v2] " Steven Rostedt
2019-04-30 21:53 ` Steven Rostedt
2019-04-30 21:53 ` rostedt
2019-05-01 1:35 ` Steven Rostedt
2019-05-01 1:35 ` Steven Rostedt
2019-05-01 1:35 ` rostedt
2019-05-01 1:58 ` Linus Torvalds
2019-05-01 1:58 ` Linus Torvalds
2019-05-01 1:58 ` torvalds
2019-05-01 8:26 ` Nicolai Stange
2019-05-01 8:26 ` Nicolai Stange
2019-05-01 8:26 ` nstange
2019-05-01 13:22 ` Steven Rostedt
2019-05-01 13:22 ` Steven Rostedt
2019-05-01 13:22 ` rostedt
2019-04-29 20:16 ` [PATCH 3/4] x86/ftrace: make ftrace_int3_handler() not to skip fops invocation Linus Torvalds
2019-04-29 20:16 ` Linus Torvalds
2019-04-29 20:16 ` torvalds
2019-04-29 22:08 ` Sean Christopherson
2019-04-29 22:08 ` Sean Christopherson
2019-04-29 22:08 ` sean.j.christopherson
2019-04-29 22:22 ` Linus Torvalds
2019-04-29 22:22 ` Linus Torvalds
2019-04-29 22:22 ` torvalds
2019-04-30 0:08 ` Sean Christopherson
2019-04-30 0:08 ` Sean Christopherson
2019-04-30 0:08 ` sean.j.christopherson
2019-04-30 0:45 ` Sean Christopherson
2019-04-30 0:45 ` Sean Christopherson
2019-04-30 0:45 ` sean.j.christopherson
2019-04-30 2:26 ` Linus Torvalds
2019-04-30 2:26 ` Linus Torvalds
2019-04-30 2:26 ` torvalds
2019-04-30 10:40 ` Peter Zijlstra
2019-04-30 10:40 ` Peter Zijlstra
2019-04-30 10:40 ` peterz
2019-04-30 11:17 ` Jiri Kosina
2019-04-30 11:17 ` Jiri Kosina
2019-04-30 11:17 ` jikos
2019-04-29 22:06 ` Linus Torvalds
2019-04-29 22:06 ` Linus Torvalds
2019-04-29 22:06 ` torvalds
2019-04-30 11:18 ` Peter Zijlstra
2019-04-30 11:18 ` Peter Zijlstra
2019-04-30 11:18 ` peterz
2019-04-29 18:52 ` Steven Rostedt
2019-04-29 18:52 ` Steven Rostedt
2019-04-29 18:52 ` rostedt
[not found] ` <CAHk-=wjm93jLtVxTX4HZs6K4k1Wqh3ujjmapqaYtcibVk_YnzQ@mail.gmail.com>
2019-04-29 19:07 ` Steven Rostedt
2019-04-29 19:07 ` Steven Rostedt
2019-04-29 19:07 ` rostedt
2019-04-29 20:06 ` Linus Torvalds
2019-04-29 20:06 ` Linus Torvalds
2019-04-29 20:06 ` torvalds
2019-04-29 20:20 ` Linus Torvalds
2019-04-29 20:20 ` Linus Torvalds
2019-04-29 20:20 ` torvalds
2019-04-29 20:30 ` Steven Rostedt
2019-04-29 20:30 ` Steven Rostedt
2019-04-29 20:30 ` rostedt
2019-04-29 21:38 ` Linus Torvalds
2019-04-29 21:38 ` Linus Torvalds
2019-04-29 21:38 ` torvalds
2019-04-29 22:07 ` Steven Rostedt
2019-04-29 22:07 ` Steven Rostedt
2019-04-29 22:07 ` rostedt
2019-04-30 9:24 ` Nicolai Stange
2019-04-30 9:24 ` Nicolai Stange
2019-04-30 9:24 ` nstange
2019-04-30 10:46 ` Peter Zijlstra
2019-04-30 10:46 ` Peter Zijlstra
2019-04-30 10:46 ` peterz
2019-04-30 13:44 ` Steven Rostedt
2019-04-30 13:44 ` Steven Rostedt
2019-04-30 13:44 ` rostedt
2019-04-30 14:20 ` Peter Zijlstra
2019-04-30 14:20 ` Peter Zijlstra
2019-04-30 14:20 ` peterz
2019-04-30 14:36 ` Steven Rostedt
2019-04-30 14:36 ` Steven Rostedt
2019-04-30 14:36 ` rostedt
2019-04-27 10:06 ` [PATCH 4/4] selftests/livepatch: add "ftrace a live patched function" test Nicolai Stange
2019-04-27 10:06 ` Nicolai Stange
2019-04-27 10:06 ` nstange
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