mirror of https://lore.kernel.org/lkml/
 help / color / mirror / Atom feed
From: Thomas Gleixner <tglx@linutronix.de>
To: john stultz <johnstul@us.ibm.com>
Cc: Andi Kleen <ak@muc.de>,
	Arne Georg Gleditsch <arne.gleditsch@dolphinics.no>,
	LKML <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@elte.hu>,
	Roman Zippel <zippel@linux-m68k.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Arjan van de Ven <arjan@infradead.org>
Subject: Re: arch/x86/kernel/vsyscall_64.c: overeager NOP of syscalls
Date: Thu, 21 Feb 2008 21:59:24 +0100 (CET)	[thread overview]
Message-ID: <alpine.LFD.1.00.0802212154550.7583@apollo.tec.linutronix.de> (raw)
In-Reply-To: <alpine.LFD.1.00.0802212129510.7583@apollo.tec.linutronix.de>

On Thu, 21 Feb 2008, Thomas Gleixner wrote:
> > That or we need to do the NOP/un-NOP part in the update_vsyscall code
> > dependent on if the current clocksource supports vread, instead of on
> > the /proc entry access.
> 
> That won't fly. We need to sychronize the CPUs when we patch the code,
> which is not possible from update_wall_time with interrupts disabled.

Also this is utterly stupid as we keep the syscall in cases where we
do not have vread anyway, so we keep the attack point open for a lot
of existing machines due to TSC wreckage and HPET unavailability.

Thanks,

	tglx

  reply	other threads:[~2008-02-21 21:01 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-20 13:57 Arne Georg Gleditsch
2008-02-20 18:08 ` Thomas Gleixner
2008-02-21 15:58 ` Andi Kleen
2008-02-21 19:45   ` Thomas Gleixner
2008-02-21 20:02     ` john stultz
2008-02-21 20:47       ` Thomas Gleixner
2008-02-21 20:59         ` Thomas Gleixner [this message]
2008-02-22 12:55           ` Andi Kleen
2008-02-22 12:49     ` Andi Kleen
2008-02-22 10:38   ` Arne Georg Gleditsch

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=alpine.LFD.1.00.0802212154550.7583@apollo.tec.linutronix.de \
    --to=tglx@linutronix.de \
    --cc=ak@muc.de \
    --cc=arjan@infradead.org \
    --cc=arne.gleditsch@dolphinics.no \
    --cc=hpa@zytor.com \
    --cc=johnstul@us.ibm.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@elte.hu \
    --cc=zippel@linux-m68k.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
all inboxes | Powered by JetHome®