From: Andy Lutomirski <luto@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Juergen Gross <jgross@suse.com>,
LKML <linux-kernel@vger.kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>, Borislav Petkov <bp@alien8.de>,
Joel Fernandes <joel@joelfernandes.org>,
He Zhe <zhe.he@windriver.com>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [RFC][PATCH] tracing/x86: Save CR2 before tracing irqsoff on error_entry
Date: Thu, 21 Mar 2019 11:28:50 -0700 [thread overview]
Message-ID: <CALCETrVd8i9xmGT9GPXU6tuvte+M9e3otYa8YNLEgPE+W81E2w@mail.gmail.com> (raw)
In-Reply-To: <20190321182745.GU5996@hirez.programming.kicks-ass.net>
On Thu, Mar 21, 2019 at 11:27 AM Peter Zijlstra <peterz@infradead.org> wrote:
>
> On Thu, Mar 21, 2019 at 11:05:06AM -0700, Andy Lutomirski wrote:
>
> > Ugh.
> >
> > I certainly agree in principle that sticking the CR2 read into the asm
> > is the right solution. But this patch makes the spaghetti even more
> > tangled. Maybe we can rearrange the code a bit so that the entry
> > sequence saves at least one register before calling error_entry, so we
> > can do it the obvious way.
>
> What is the obvious way? Note that with all the Xen/paravirt-me-harder
> bits on, we need to clobber at least RAX to get CR2.
>
> And most of the patch was munging the paravirt bits to make that happen.
>
> Another thing I did notices is that CLAC and CLD are not next to one
> another in these paths.
The thing I really don't like is all the EBX crud to try to get
everything in to the right order.
next prev parent reply other threads:[~2019-03-21 18:29 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-21 2:15 [RFC][PATCH] tracing/x86: Save CR2 before tracing irqsoff on error_entry Steven Rostedt
2019-03-21 8:33 ` Peter Zijlstra
2019-03-21 9:02 ` Peter Zijlstra
2019-03-21 10:45 ` Peter Zijlstra
2019-03-21 13:32 ` Steven Rostedt
2019-03-21 13:55 ` Steven Rostedt
2019-03-21 17:23 ` Linus Torvalds
2019-03-21 17:22 ` Peter Zijlstra
2019-03-21 18:05 ` Andy Lutomirski
2019-03-21 18:10 ` Steven Rostedt
2019-03-21 18:27 ` Andy Lutomirski
2019-03-21 20:50 ` Peter Zijlstra
2019-03-22 2:52 ` Andy Lutomirski
2019-03-21 18:28 ` Peter Zijlstra
2019-03-21 18:55 ` Steven Rostedt
2019-03-21 19:31 ` Peter Zijlstra
2019-03-21 19:50 ` Steven Rostedt
2019-03-21 20:03 ` Peter Zijlstra
2019-03-21 20:11 ` Steven Rostedt
2019-03-21 18:18 ` Linus Torvalds
2019-03-21 18:20 ` Andy Lutomirski
2019-03-21 18:25 ` Linus Torvalds
2019-03-21 18:37 ` Peter Zijlstra
2019-03-21 18:39 ` Andy Lutomirski
2019-03-21 20:00 ` Andrew Cooper
2019-03-21 20:35 ` Steven Rostedt
2019-03-21 18:38 ` Andy Lutomirski
2019-03-21 18:42 ` Peter Zijlstra
2019-03-21 18:22 ` hpa
2019-03-22 5:54 ` Juergen Gross
2019-03-21 18:27 ` Peter Zijlstra
2019-03-21 18:28 ` Andy Lutomirski [this message]
2019-03-21 18:33 ` Peter Zijlstra
2019-03-21 13:04 ` Steven Rostedt
2019-04-17 1:52 ` He Zhe
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