From: Peter Zijlstra <peterz@infradead.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Andy Lutomirski <luto@amacapital.net>,
Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Andy Lutomirski <luto@kernel.org>,
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>,
the arch/x86 maintainers <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>,
Joerg Roedel <jroedel@suse.de>,
"open list:KERNEL SELFTEST FRAMEWORK"
<linux-kselftest@vger.kernel.org>,
stable <stable@vger.kernel.org>,
Masami Hiramatsu <mhiramat@kernel.org>
Subject: Re: [RFC][PATCH 1/2] x86: Allow breakpoints to emulate call functions
Date: Tue, 7 May 2019 19:38:29 +0200 [thread overview]
Message-ID: <20190507173829.GY2606@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <CAHk-=wiuue37opWK5QaQ9f6twqDZuSratdP-1bK6kD9-Az5WnA@mail.gmail.com>
On Tue, May 07, 2019 at 10:08:50AM -0700, Linus Torvalds wrote:
> On Tue, May 7, 2019 at 9:34 AM Peter Zijlstra <peterz@infradead.org> wrote:
> >
> > Would you consider my approach later on, under the guise of unification?
>
> WHY?
>
> The *only* advantage of your patch is that trivial "look up kernel stack" macro.
>
> Seriously. There's absolutely nothing else.
The ftrace_regs_caller, the kprobe tramplines, the unwinder, they all
have 'funny' bits because pt_regs isn't 'right'.
> So the whole "let's clean up x86-32 to look like x86-64, which got
> things right" is to me a completely bogus argument. x86-64 got the
> "yes, push ss/sp unconditionally" part right, but got a lot of other
> things horribly wrong. So this is all just one small detail that
> differs, across two architectures that are similar but have very
> different warts.
It's a detail that leaks into the C code. Yes SWAPGS is horrible crap,
but C code doesn't much care. The partial pt_regs thing otoh comes up a
fair number of times.
Anyway; I think we're at the point where we'll have to agree to
disagree (or maybe slightly past it).
WARNING: multiple messages have this Message-ID (diff)
From: peterz at infradead.org (Peter Zijlstra)
Subject: [RFC][PATCH 1/2] x86: Allow breakpoints to emulate call functions
Date: Tue, 7 May 2019 19:38:29 +0200 [thread overview]
Message-ID: <20190507173829.GY2606@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <CAHk-=wiuue37opWK5QaQ9f6twqDZuSratdP-1bK6kD9-Az5WnA@mail.gmail.com>
On Tue, May 07, 2019 at 10:08:50AM -0700, Linus Torvalds wrote:
> On Tue, May 7, 2019 at 9:34 AM Peter Zijlstra <peterz at infradead.org> wrote:
> >
> > Would you consider my approach later on, under the guise of unification?
>
> WHY?
>
> The *only* advantage of your patch is that trivial "look up kernel stack" macro.
>
> Seriously. There's absolutely nothing else.
The ftrace_regs_caller, the kprobe tramplines, the unwinder, they all
have 'funny' bits because pt_regs isn't 'right'.
> So the whole "let's clean up x86-32 to look like x86-64, which got
> things right" is to me a completely bogus argument. x86-64 got the
> "yes, push ss/sp unconditionally" part right, but got a lot of other
> things horribly wrong. So this is all just one small detail that
> differs, across two architectures that are similar but have very
> different warts.
It's a detail that leaks into the C code. Yes SWAPGS is horrible crap,
but C code doesn't much care. The partial pt_regs thing otoh comes up a
fair number of times.
Anyway; I think we're at the point where we'll have to agree to
disagree (or maybe slightly past it).
WARNING: multiple messages have this Message-ID (diff)
From: peterz@infradead.org (Peter Zijlstra)
Subject: [RFC][PATCH 1/2] x86: Allow breakpoints to emulate call functions
Date: Tue, 7 May 2019 19:38:29 +0200 [thread overview]
Message-ID: <20190507173829.GY2606@hirez.programming.kicks-ass.net> (raw)
Message-ID: <20190507173829.DfS3LM8ESO5xjPXHV0H1krbt5Cgf3F_W2oYst5vnUzQ@z> (raw)
In-Reply-To: <CAHk-=wiuue37opWK5QaQ9f6twqDZuSratdP-1bK6kD9-Az5WnA@mail.gmail.com>
On Tue, May 07, 2019@10:08:50AM -0700, Linus Torvalds wrote:
> On Tue, May 7, 2019@9:34 AM Peter Zijlstra <peterz@infradead.org> wrote:
> >
> > Would you consider my approach later on, under the guise of unification?
>
> WHY?
>
> The *only* advantage of your patch is that trivial "look up kernel stack" macro.
>
> Seriously. There's absolutely nothing else.
The ftrace_regs_caller, the kprobe tramplines, the unwinder, they all
have 'funny' bits because pt_regs isn't 'right'.
> So the whole "let's clean up x86-32 to look like x86-64, which got
> things right" is to me a completely bogus argument. x86-64 got the
> "yes, push ss/sp unconditionally" part right, but got a lot of other
> things horribly wrong. So this is all just one small detail that
> differs, across two architectures that are similar but have very
> different warts.
It's a detail that leaks into the C code. Yes SWAPGS is horrible crap,
but C code doesn't much care. The partial pt_regs thing otoh comes up a
fair number of times.
Anyway; I think we're at the point where we'll have to agree to
disagree (or maybe slightly past it).
next prev parent reply other threads:[~2019-05-07 17:38 UTC|newest]
Thread overview: 307+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-01 20:28 [RFC][PATCH 0/2] ftrace/x86: Allow for breakpoint handlers to emulate call functions Steven Rostedt
2019-05-01 20:28 ` [RFC][PATCH 1/2] x86: Allow breakpoints " Steven Rostedt
2019-05-01 20:28 ` Steven Rostedt
2019-05-01 20:28 ` rostedt
2019-05-02 3:24 ` Steven Rostedt
2019-05-02 3:24 ` Steven Rostedt
2019-05-02 3:24 ` rostedt
2019-05-02 16:21 ` Peter Zijlstra
2019-05-02 16:21 ` Peter Zijlstra
2019-05-02 16:21 ` peterz
2019-05-02 16:29 ` Peter Zijlstra
2019-05-02 16:29 ` Peter Zijlstra
2019-05-02 16:29 ` peterz
2019-05-02 18:02 ` Linus Torvalds
2019-05-02 18:02 ` Linus Torvalds
2019-05-02 18:02 ` torvalds
2019-05-02 18:18 ` Peter Zijlstra
2019-05-02 18:18 ` Peter Zijlstra
2019-05-02 18:18 ` peterz
2019-05-02 18:30 ` Peter Zijlstra
2019-05-02 18:30 ` Peter Zijlstra
2019-05-02 18:30 ` peterz
2019-05-02 18:43 ` Linus Torvalds
2019-05-02 18:43 ` Linus Torvalds
2019-05-02 18:43 ` torvalds
2019-05-02 19:28 ` Jiri Kosina
2019-05-02 19:28 ` Jiri Kosina
2019-05-02 19:28 ` jikos
2019-05-02 20:25 ` Andy Lutomirski
2019-05-02 20:25 ` Andy Lutomirski
2019-05-02 20:25 ` luto
2019-05-02 20:21 ` Peter Zijlstra
2019-05-02 20:21 ` Peter Zijlstra
2019-05-02 20:21 ` peterz
2019-05-02 20:49 ` Linus Torvalds
2019-05-02 20:49 ` Linus Torvalds
2019-05-02 20:49 ` torvalds
2019-05-02 21:32 ` Peter Zijlstra
2019-05-02 21:32 ` Peter Zijlstra
2019-05-02 21:32 ` peterz
2019-05-03 19:24 ` Steven Rostedt
2019-05-03 19:24 ` Steven Rostedt
2019-05-03 19:24 ` rostedt
2019-05-03 21:46 ` Linus Torvalds
2019-05-03 21:46 ` Linus Torvalds
2019-05-03 21:46 ` torvalds
2019-05-03 22:49 ` Steven Rostedt
2019-05-03 22:49 ` Steven Rostedt
2019-05-03 22:49 ` rostedt
2019-05-03 23:07 ` Linus Torvalds
2019-05-03 23:07 ` Linus Torvalds
2019-05-03 23:07 ` torvalds
2019-05-04 4:17 ` Steven Rostedt
2019-05-04 4:17 ` Steven Rostedt
2019-05-04 4:17 ` rostedt
[not found] ` <CAHk-=wiuSFbv_rELND-BLWcP0GSZ0yF=xOAEcf61GE3bU9d=yg@mail.gmail.com>
2019-05-04 18:59 ` Linus Torvalds
2019-05-04 18:59 ` Linus Torvalds
2019-05-04 18:59 ` torvalds
2019-05-04 20:12 ` Andy Lutomirski
2019-05-04 20:12 ` Andy Lutomirski
2019-05-04 20:12 ` luto
2019-05-04 20:28 ` Linus Torvalds
2019-05-04 20:28 ` Linus Torvalds
2019-05-04 20:28 ` torvalds
2019-05-04 20:36 ` Linus Torvalds
2019-05-04 20:36 ` Linus Torvalds
2019-05-04 20:36 ` torvalds
2019-05-03 22:55 ` Andy Lutomirski
2019-05-03 22:55 ` Andy Lutomirski
2019-05-03 22:55 ` luto
2019-05-03 23:16 ` Linus Torvalds
2019-05-03 23:16 ` Linus Torvalds
2019-05-03 23:16 ` torvalds
2019-05-03 23:32 ` Andy Lutomirski
2019-05-03 23:32 ` Andy Lutomirski
2019-05-03 23:32 ` luto
2019-05-02 22:52 ` Steven Rostedt
2019-05-02 22:52 ` Steven Rostedt
2019-05-02 22:52 ` rostedt
2019-05-02 23:31 ` Steven Rostedt
2019-05-02 23:31 ` Steven Rostedt
2019-05-02 23:31 ` rostedt
2019-05-02 23:50 ` Steven Rostedt
2019-05-02 23:50 ` Steven Rostedt
2019-05-02 23:50 ` rostedt
2019-05-03 1:51 ` [RFC][PATCH 1/2 v2] " Steven Rostedt
2019-05-03 1:51 ` Steven Rostedt
2019-05-03 1:51 ` rostedt
2019-05-03 9:29 ` [RFC][PATCH 1/2] " Peter Zijlstra
2019-05-03 9:29 ` Peter Zijlstra
2019-05-03 9:29 ` peterz
2019-05-03 13:22 ` Steven Rostedt
2019-05-03 13:22 ` Steven Rostedt
2019-05-03 13:22 ` rostedt
2019-05-03 16:20 ` Andy Lutomirski
2019-05-03 16:20 ` Andy Lutomirski
2019-05-03 16:20 ` luto
2019-05-03 16:31 ` Steven Rostedt
2019-05-03 16:31 ` Steven Rostedt
2019-05-03 16:31 ` rostedt
2019-05-03 16:35 ` Peter Zijlstra
2019-05-03 16:35 ` Peter Zijlstra
2019-05-03 16:35 ` peterz
2019-05-03 16:44 ` Andy Lutomirski
2019-05-03 16:44 ` Andy Lutomirski
2019-05-03 16:44 ` luto
2019-05-03 16:49 ` Steven Rostedt
2019-05-03 16:49 ` Steven Rostedt
2019-05-03 16:49 ` rostedt
2019-05-03 16:32 ` Peter Zijlstra
2019-05-03 16:32 ` Peter Zijlstra
2019-05-03 16:32 ` peterz
2019-05-03 18:57 ` Linus Torvalds
2019-05-03 18:57 ` Linus Torvalds
2019-05-03 18:57 ` torvalds
2019-05-06 8:19 ` Peter Zijlstra
2019-05-06 8:19 ` Peter Zijlstra
2019-05-06 8:19 ` peterz
2019-05-06 13:56 ` Steven Rostedt
2019-05-06 13:56 ` Steven Rostedt
2019-05-06 13:56 ` rostedt
2019-05-06 16:17 ` Linus Torvalds
2019-05-06 16:17 ` Linus Torvalds
2019-05-06 16:17 ` torvalds
2019-05-06 16:19 ` Linus Torvalds
2019-05-06 16:19 ` Linus Torvalds
2019-05-06 16:19 ` torvalds
2019-05-06 17:06 ` Steven Rostedt
2019-05-06 17:06 ` Steven Rostedt
2019-05-06 17:06 ` rostedt
2019-05-06 18:06 ` Linus Torvalds
2019-05-06 18:06 ` Linus Torvalds
2019-05-06 18:06 ` torvalds
2019-05-06 18:57 ` Steven Rostedt
2019-05-06 18:57 ` Steven Rostedt
2019-05-06 18:57 ` rostedt
2019-05-06 19:46 ` Linus Torvalds
2019-05-06 19:46 ` Linus Torvalds
2019-05-06 19:46 ` torvalds
2019-05-06 20:29 ` Steven Rostedt
2019-05-06 20:29 ` Steven Rostedt
2019-05-06 20:29 ` rostedt
2019-05-06 20:42 ` Linus Torvalds
2019-05-06 20:42 ` Linus Torvalds
2019-05-06 20:42 ` torvalds
2019-05-06 20:44 ` Linus Torvalds
2019-05-06 20:44 ` Linus Torvalds
2019-05-06 20:44 ` torvalds
2019-05-06 21:45 ` Steven Rostedt
2019-05-06 21:45 ` Steven Rostedt
2019-05-06 21:45 ` rostedt
2019-05-06 22:06 ` Linus Torvalds
2019-05-06 22:06 ` Linus Torvalds
2019-05-06 22:06 ` torvalds
2019-05-06 22:31 ` Linus Torvalds
2019-05-06 22:31 ` Linus Torvalds
2019-05-06 22:31 ` torvalds
2019-05-07 0:10 ` Steven Rostedt
2019-05-07 0:10 ` Steven Rostedt
2019-05-07 0:10 ` rostedt
2019-05-07 1:06 ` Linus Torvalds
2019-05-07 1:06 ` Linus Torvalds
2019-05-07 1:06 ` torvalds
2019-05-07 1:04 ` Steven Rostedt
2019-05-07 1:04 ` Steven Rostedt
2019-05-07 1:04 ` rostedt
2019-05-07 1:34 ` Steven Rostedt
2019-05-07 1:34 ` Steven Rostedt
2019-05-07 1:34 ` rostedt
2019-05-07 1:34 ` Linus Torvalds
2019-05-07 1:34 ` Linus Torvalds
2019-05-07 1:34 ` torvalds
2019-05-07 1:53 ` Steven Rostedt
2019-05-07 1:53 ` Steven Rostedt
2019-05-07 1:53 ` rostedt
2019-05-07 2:22 ` Linus Torvalds
2019-05-07 2:22 ` Linus Torvalds
2019-05-07 2:22 ` torvalds
2019-05-07 2:58 ` Steven Rostedt
2019-05-07 2:58 ` Steven Rostedt
2019-05-07 2:58 ` rostedt
2019-05-07 3:05 ` Linus Torvalds
2019-05-07 3:05 ` Linus Torvalds
2019-05-07 3:05 ` torvalds
2019-05-07 3:21 ` Steven Rostedt
2019-05-07 3:21 ` Steven Rostedt
2019-05-07 3:21 ` rostedt
2019-05-07 3:28 ` Linus Torvalds
2019-05-07 3:28 ` Linus Torvalds
2019-05-07 3:28 ` torvalds
2019-05-07 14:54 ` Linus Torvalds
2019-05-07 14:54 ` Linus Torvalds
2019-05-07 14:54 ` torvalds
2019-05-07 15:12 ` Steven Rostedt
2019-05-07 15:12 ` Steven Rostedt
2019-05-07 15:12 ` rostedt
2019-05-07 15:25 ` Steven Rostedt
2019-05-07 15:25 ` Steven Rostedt
2019-05-07 15:25 ` rostedt
2019-05-07 16:25 ` Steven Rostedt
2019-05-07 16:25 ` Steven Rostedt
2019-05-07 16:25 ` rostedt
2019-05-07 15:31 ` Linus Torvalds
2019-05-07 15:31 ` Linus Torvalds
2019-05-07 15:31 ` torvalds
2019-05-07 15:45 ` Steven Rostedt
2019-05-07 15:45 ` Steven Rostedt
2019-05-07 15:45 ` rostedt
2019-05-07 16:34 ` Peter Zijlstra
2019-05-07 16:34 ` Peter Zijlstra
2019-05-07 16:34 ` peterz
2019-05-07 17:08 ` Linus Torvalds
2019-05-07 17:08 ` Linus Torvalds
2019-05-07 17:08 ` torvalds
2019-05-07 17:21 ` Josh Poimboeuf
2019-05-07 17:21 ` Josh Poimboeuf
2019-05-07 17:21 ` jpoimboe
2019-05-07 21:24 ` Steven Rostedt
2019-05-07 21:24 ` Steven Rostedt
2019-05-07 21:24 ` rostedt
2019-05-08 4:50 ` Linus Torvalds
2019-05-08 4:50 ` Linus Torvalds
2019-05-08 4:50 ` torvalds
2019-05-08 16:37 ` Steven Rostedt
2019-05-08 16:37 ` Steven Rostedt
2019-05-08 16:37 ` rostedt
2019-05-07 17:38 ` Peter Zijlstra [this message]
2019-05-07 17:38 ` Peter Zijlstra
2019-05-07 17:38 ` peterz
2019-05-07 9:51 ` Peter Zijlstra
2019-05-07 9:51 ` Peter Zijlstra
2019-05-07 9:51 ` peterz
2019-05-07 14:48 ` Andy Lutomirski
2019-05-07 14:48 ` Andy Lutomirski
2019-05-07 14:48 ` luto
2019-05-07 14:57 ` Linus Torvalds
2019-05-07 14:57 ` Linus Torvalds
2019-05-07 14:57 ` torvalds
2019-05-07 14:13 ` Masami Hiramatsu
2019-05-07 14:13 ` Masami Hiramatsu
2019-05-07 14:13 ` mhiramat
2019-05-07 17:15 ` Masami Hiramatsu
2019-05-07 17:15 ` Masami Hiramatsu
2019-05-07 17:15 ` mhiramat
2019-05-06 14:22 ` Peter Zijlstra
2019-05-06 14:22 ` Peter Zijlstra
2019-05-06 14:22 ` peterz
2019-05-07 8:57 ` Peter Zijlstra
2019-05-07 8:57 ` Peter Zijlstra
2019-05-07 8:57 ` peterz
2019-05-07 9:18 ` David Laight
2019-05-07 9:18 ` David Laight
2019-05-07 9:18 ` David.Laight
2019-05-07 11:30 ` Peter Zijlstra
2019-05-07 11:30 ` Peter Zijlstra
2019-05-07 11:30 ` peterz
2019-05-07 12:57 ` David Laight
2019-05-07 12:57 ` David Laight
2019-05-07 12:57 ` David.Laight
2019-05-07 13:14 ` Steven Rostedt
2019-05-07 13:14 ` Steven Rostedt
2019-05-07 13:14 ` rostedt
2019-05-07 14:50 ` David Laight
2019-05-07 14:50 ` David Laight
2019-05-07 14:50 ` David.Laight
2019-05-07 14:57 ` Steven Rostedt
2019-05-07 14:57 ` Steven Rostedt
2019-05-07 14:57 ` rostedt
2019-05-07 15:46 ` David Laight
2019-05-07 15:46 ` David Laight
2019-05-07 15:46 ` David.Laight
2019-05-07 13:32 ` Peter Zijlstra
2019-05-07 13:32 ` Peter Zijlstra
2019-05-07 13:32 ` peterz
2019-05-07 9:27 ` Peter Zijlstra
2019-05-07 9:27 ` Peter Zijlstra
2019-05-07 9:27 ` peterz
2019-05-07 12:27 ` Steven Rostedt
2019-05-07 12:27 ` Steven Rostedt
2019-05-07 12:27 ` rostedt
2019-05-07 12:41 ` Peter Zijlstra
2019-05-07 12:41 ` Peter Zijlstra
2019-05-07 12:41 ` peterz
2019-05-07 12:54 ` Steven Rostedt
2019-05-07 12:54 ` Steven Rostedt
2019-05-07 12:54 ` rostedt
2019-05-07 17:22 ` Masami Hiramatsu
2019-05-07 17:22 ` Masami Hiramatsu
2019-05-07 17:22 ` masami.hiramatsu
2019-05-07 14:28 ` Peter Zijlstra
2019-05-07 14:28 ` Peter Zijlstra
2019-05-07 14:28 ` peterz
2019-05-02 20:48 ` Steven Rostedt
2019-05-02 20:48 ` Steven Rostedt
2019-05-02 20:48 ` rostedt
2019-05-06 15:14 ` Josh Poimboeuf
2019-05-06 15:14 ` Josh Poimboeuf
2019-05-06 15:14 ` jpoimboe
2019-05-01 20:28 ` [RFC][PATCH 2/2] ftrace/x86: Emulate call function while updating in breakpoint handler Steven Rostedt
2019-05-01 20:28 ` Steven Rostedt
2019-05-01 20:28 ` rostedt
2019-05-03 10:22 ` [RFC][PATCH 1.5/2] x86: Add int3_emulate_call() selftest Peter Zijlstra
2019-05-03 10:22 ` Peter Zijlstra
2019-05-03 10:22 ` peterz
2019-05-03 18:46 ` Steven Rostedt
2019-05-03 18:46 ` Steven Rostedt
2019-05-03 18:46 ` rostedt
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