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From: "H. Peter Anvin" <hpa@zytor.com>
To: Kees Cook <keescook@chromium.org>
Cc: linux-kernel@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	x86@kernel.org, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	Jeremy Fitzhardinge <jeremy@goop.org>,
	Marcelo Tosatti <mtosatti@redhat.com>,
	Alex Shi <alex.shi@intel.com>,
	Alexander Duyck <alexander.h.duyck@intel.com>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	xen-devel@lists.xensource.com,
	virtualization@lists.linux-foundation.org,
	kernel-hardening@lists.openwall.com,
	Dan Rosenberg <drosenberg@vsecurity.com>,
	Julien Tinnes <jln@google.com>, Will Drewry <wad@chromium.org>,
	Eric Northup <digitaleric@google.com>
Subject: Re: [PATCH v2] x86: use fixed read-only IDT
Date: Tue, 09 Apr 2013 17:14:45 -0700	[thread overview]
Message-ID: <5164AEF5.9020202@zytor.com> (raw)
In-Reply-To: <20130409163932.GA19130@www.outflux.net>

On 04/09/2013 09:39 AM, Kees Cook wrote:
> -
>  static void __cpuinit intel_smp_check(struct cpuinfo_x86 *c)
>  {
>  	/* calling is from identify_secondary_cpu() ? */
> @@ -206,8 +192,7 @@ static void __cpuinit intel_workarounds(struct cpuinfo_x86 *c)
>  	/*
>  	 * All current models of Pentium and Pentium with MMX technology CPUs
>  	 * have the F0 0F bug, which lets nonprivileged users lock up the
> -	 * system.
> -	 * Note that the workaround only should be initialized once...
> +	 * system. Announce that the fault handler will be checking for it.
>  	 */
>  	c->f00f_bug = 0;
>  	if (!paravirt_enabled() && c->x86 == 5) {
> @@ -215,7 +200,6 @@ static void __cpuinit intel_workarounds(struct cpuinfo_x86 *c)
>  
>  		c->f00f_bug = 1;
>  		if (!f00f_workaround_enabled) {
> -			trap_init_f00f_bug();
>  			printk(KERN_NOTICE "Intel Pentium with F0 0F bug - workaround enabled.\n");
>  			f00f_workaround_enabled = 1;
>  		}

Why do we care about this message anymore?  It provides no relevant user
information, the flag itself is already in /proc/cpuinfo, and the
message is likely to be wrong since all it does is look for an Intel CPU
with family == 5.

	-hpa



  reply	other threads:[~2013-04-10  0:21 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-04-09 16:39 Kees Cook
2013-04-10  0:14 ` H. Peter Anvin [this message]
2013-04-10  0:29   ` Kees Cook
2013-04-10  0:26 ` [tip:x86/cpu] x86: Use a read-only IDT alias on all CPUs tip-bot for Kees Cook

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