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From: Dave Hansen <dave.hansen@linux.intel.com>
To: Kees Cook <keescook@chromium.org>, "H. Peter Anvin" <hpa@zytor.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
	"Rik van Riel" <riel@redhat.com>,
	"Andy Lutomirski" <luto@kernel.org>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Ingo Molnar" <mingo@redhat.com>,
	"x86@kernel.org" <x86@kernel.org>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Yu-cheng Yu" <yu-cheng.yu@intel.com>,
	"Masahiro Yamada" <yamada.masahiro@socionext.com>,
	"Borislav Petkov" <bp@suse.de>,
	"Christian Borntraeger" <borntraeger@de.ibm.com>,
	"Thomas Garnier" <thgarnie@google.com>,
	"Brian Gerst" <brgerst@gmail.com>,
	"He Chen" <he.chen@linux.intel.com>,
	"Mathias Krause" <minipli@googlemail.com>,
	"Fenghua Yu" <fenghua.yu@intel.com>,
	"Piotr Luc" <piotr.luc@intel.com>, "Kyle Huey" <me@kylehuey.com>,
	"Len Brown" <len.brown@intel.com>, KVM <kvm@vger.kernel.org>,
	"kernel-hardening@lists.openwall.com"
	<kernel-hardening@lists.openwall.com>
Subject: [kernel-hardening] Re: [PATCH] x86/fpu: move FPU state into separate cache
Date: Wed, 29 Mar 2017 14:19:37 -0700	[thread overview]
Message-ID: <ca888ec2-e2e6-3600-3e39-c18e61e0c735@linux.intel.com> (raw)
In-Reply-To: <CAGXu5jLQfS6gK2MyetWPjyJDOg8NdACXsPXLt7OasQE03VUwPg@mail.gmail.com>

On 03/29/2017 02:09 PM, Kees Cook wrote:
> They're adjacent already, which poses a problem for the struct layout
> randomization plugin, since adjacency may no longer be true (after
> layout randomization). This adjacency (or not) isn't really the
> problem: it's that FPU state size is only known at runtime. Another
> solution would be to have FPU state be a fixed size...

We don't want that.  It varies from a couple hundred bytes to ~3k on
newer CPUs.  We don't want to eat an extra 2.5k per task on the older
processors.

  reply	other threads:[~2017-03-29 21:19 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-29 20:39 [kernel-hardening] [PATCH] x86/fpu: move FPU state into separate cache Kees Cook
2017-03-29 20:45 ` [kernel-hardening] " H. Peter Anvin
2017-03-29 21:09   ` Kees Cook
2017-03-29 21:19     ` Dave Hansen [this message]
2017-03-29 21:30     ` Linus Torvalds
2017-03-29 21:35       ` Andy Lutomirski
2017-03-29 21:41         ` Linus Torvalds
2017-03-29 22:28           ` hpa
2017-03-29 23:56             ` Linus Torvalds
2017-03-30  1:50               ` Kees Cook
2017-03-29 21:35       ` Linus Torvalds
2017-03-31  4:59 ` kbuild test robot
2017-03-31  5:57 ` kbuild test robot

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