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: [kernel-hardening] 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
WARNING: multiple messages have this Message-ID (diff)
From: "H. Peter Anvin" <hpa@zytor.com>
To: Kees Cook <keescook@chromium.org>
Cc: Alexander Duyck <alexander.h.duyck@intel.com>,
Alex Shi <alex.shi@intel.com>,
Jeremy Fitzhardinge <jeremy@goop.org>,
Will Drewry <wad@chromium.org>, Julien Tinnes <jln@google.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Dan Rosenberg <drosenberg@vsecurity.com>,
x86@kernel.org, linux-kernel@vger.kernel.org,
Steven Rostedt <rostedt@goodmis.org>,
virtualization@lists.linux-foundation.org,
Ingo Molnar <mingo@redhat.com>,
kernel-hardening@lists.openwall.com,
Thomas Gleixner <tglx@linutronix.de>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
xen-devel@lists.xensource.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
WARNING: multiple messages have this Message-ID (diff)
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
next prev parent reply other threads:[~2013-04-10 0:14 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-09 16:39 [kernel-hardening] [PATCH v2] x86: use fixed read-only IDT Kees Cook
2013-04-09 16:39 ` Kees Cook
2013-04-09 16:39 ` Kees Cook
2013-04-10 0:14 ` H. Peter Anvin [this message]
2013-04-10 0:14 ` H. Peter Anvin
2013-04-10 0:14 ` H. Peter Anvin
2013-04-10 0:29 ` [kernel-hardening] " Kees Cook
2013-04-10 0:29 ` Kees Cook
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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