All of lore.kernel.org
 help / color / mirror / Atom feed
From: "H. Peter Anvin" <hpa@zytor.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Jan Kiszka <jan.kiszka@siemens.com>,
	Fenghua Yu <fenghua.yu@intel.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	x86 <x86@kernel.org>, Ingo Molnar <mingo@elte.hu>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: x86-32: Early microcode loading stumbles over disabled DYNAMIC_FTRACE
Date: Fri, 30 Aug 2013 09:35:18 -0700	[thread overview]
Message-ID: <5220C9C6.5020808@zytor.com> (raw)
In-Reply-To: <20130830115142.1ee4c825@gandalf.local.home>

On 08/30/2013 08:51 AM, Steven Rostedt wrote:
> 
> It does when dynamic tracing is enabled. But this issue is with static
> tracing, there's no code modification, thus all functions call
> mcount/__fentry__ and we need to look at a variable to determine if we
> should trace or not.
> 

And of course global variables are a no-no without special handling in
pre-paging mode.  Sigh.

You *could* bail out of the calling address is < PAGE_OFFSET.

	-hpa


  reply	other threads:[~2013-08-30 16:36 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-08-23 16:40 x86-32: Early microcode loading stumbles over disabled DYNAMIC_FTRACE Jan Kiszka
2013-08-23 20:17 ` Borislav Petkov
2013-08-26  8:50   ` Jan Kiszka
2013-08-30 15:36 ` H. Peter Anvin
2013-08-30 15:51   ` Steven Rostedt
2013-08-30 16:35     ` H. Peter Anvin [this message]
2013-08-30 17:03       ` Steven Rostedt
2013-08-30 17:16         ` H. Peter Anvin
2013-08-30 17:25           ` Steven Rostedt
2013-08-30 17:33             ` Jan Kiszka
2013-08-30 20:48         ` H. Peter Anvin
2013-08-31  0:17           ` Steven Rostedt
2013-08-31  5:07             ` Borislav Petkov
2013-08-31  5:23               ` 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=5220C9C6.5020808@zytor.com \
    --to=hpa@zytor.com \
    --cc=fenghua.yu@intel.com \
    --cc=jan.kiszka@siemens.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@elte.hu \
    --cc=rostedt@goodmis.org \
    --cc=tglx@linutronix.de \
    --cc=x86@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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.