From: Andi Kleen <andi@firstfloor.org>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>,
Mikael Pettersson <mikpe@it.uu.se>,
mingo@elte.hu, tglx@linutronix.de, torvalds@linux-foundation.org,
akpm@linux-foundation.org, roland@redhat.com, drepper@redhat.com,
Hongjiu.lu@intel.com, linux-kernel@vger.kernel.org,
arjan@linux.intel.com, rmk+lkml@arm.linux.org.uk, dan@debian.org,
asit.k.mallick@intel.com
Subject: Re: [RFC] x86: xsave/xrstor support, ucontext_t extensions
Date: Tue, 20 May 2008 17:03:55 +0200 [thread overview]
Message-ID: <4832E85B.4080303@firstfloor.org> (raw)
In-Reply-To: <4832E672.3090702@zytor.com>
H. Peter Anvin wrote:
> Andi Kleen wrote:
>>> Ok. CPU folks are planning to make some of the bytes at the end of
>>> fxsave
>>> image, SW usable.
>>
>> Are they always zeroed in earlier CPUs though? If not that wouldn't
>> work 100% reliably because whatever cookie you put in could have been
>> there before by chance.
>>
>> I don't see anything in the SDM guaranteeing zeroing.
>>
>
> I'm pretty sure they weren't zeroed by the CPUs. If they weren't zeroed
> *by the kernel*, there might have been an information leak.
I don't think there is one. We never copy fxsave completely out of the
kernel. x86-64 does FXSAVE directly in/out user space, but the
only leak is what there was before.
-Andi
next prev parent reply other threads:[~2008-05-20 15:04 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-05-13 1:10 [RFC] x86: xsave/xrstor support, ucontext_t extensions Suresh Siddha
2008-05-16 13:26 ` Mikael Pettersson
2008-05-18 1:34 ` Suresh Siddha
2008-05-19 14:52 ` Mikael Pettersson
2008-05-19 15:04 ` Andi Kleen
2008-05-19 16:29 ` H. Peter Anvin
2008-05-19 16:57 ` Suresh Siddha
2008-05-19 17:45 ` H. Peter Anvin
2008-05-20 1:57 ` Suresh Siddha
2008-05-20 8:58 ` Mikael Pettersson
2008-05-20 10:01 ` Andi Kleen
2008-05-20 13:19 ` Mikael Pettersson
2008-05-20 14:58 ` H. Peter Anvin
2008-05-20 15:20 ` Mikael Pettersson
2008-05-20 17:53 ` Suresh Siddha
2008-05-20 17:59 ` H. Peter Anvin
2008-05-22 0:28 ` H. Peter Anvin
2008-05-22 0:53 ` Roland McGrath
2008-05-22 1:38 ` H. Peter Anvin
2008-05-22 6:40 ` Roland McGrath
2008-05-22 7:18 ` H. Peter Anvin
2008-05-22 8:49 ` Mikael Pettersson
2008-05-22 8:57 ` Mikael Pettersson
2008-05-22 20:56 ` Suresh Siddha
2008-05-22 21:02 ` H. Peter Anvin
2008-05-22 21:29 ` Suresh Siddha
2008-05-22 21:34 ` H. Peter Anvin
2008-05-22 22:22 ` Mikael Pettersson
2008-05-23 1:48 ` Suresh Siddha
2008-05-23 2:12 ` Roland McGrath
2008-05-23 2:49 ` H. Peter Anvin
2008-05-23 18:09 ` Suresh Siddha
2008-06-06 0:28 ` x86: xsave/xrstor support; " H. Peter Anvin
2008-06-06 20:14 ` Suresh Siddha
2008-06-06 23:03 ` H. Peter Anvin
2008-05-23 2:45 ` [RFC] x86: xsave/xrstor support, " H. Peter Anvin
2008-05-23 11:46 ` Mikael Pettersson
2008-05-23 12:11 ` Andi Kleen
2008-05-22 21:32 ` Chris Wright
2008-05-22 22:15 ` Mikael Pettersson
2008-05-22 22:29 ` Chris Wright
2008-05-23 0:32 ` H. Peter Anvin
2008-05-23 0:44 ` Chris Wright
2008-05-22 22:36 ` Mikael Pettersson
2008-05-23 0:33 ` H. Peter Anvin
2008-05-23 0:42 ` Suresh Siddha
2008-05-23 1:33 ` Roland McGrath
2008-05-23 16:57 ` H. Peter Anvin
2008-05-23 17:50 ` Suresh Siddha
2008-05-23 2:27 ` H. Peter Anvin
2008-05-20 17:57 ` H. Peter Anvin
2008-05-20 14:55 ` H. Peter Anvin
2008-05-20 15:03 ` Andi Kleen [this message]
2008-05-20 20:10 ` Roland McGrath
2008-05-22 0:05 ` H. Peter Anvin
2008-05-22 0:47 ` Roland McGrath
2008-05-22 8:14 ` Andi Kleen
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