From: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>, Julia Lawall <julia.lawall@lip6.fr>,
Linus Torvalds <torvalds@linux-foundation.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
linux-arch@vger.kernel.org, Peter Zijlstra <peterz@infradead.org>,
Greg KH <gregkh@linuxfoundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Elena Reshetova <elena.reshetova@intel.com>,
Alan Cox <alan@linux.intel.com>,
Dan Carpenter <dan.carpenter@oracle.com>
Subject: Re: [RFC PATCH] asm/generic: introduce if_nospec and nospec_barrier
Date: Thu, 4 Jan 2018 23:21:10 +0000 [thread overview]
Message-ID: <20180104232110.4a18b7b1@alans-desktop> (raw)
In-Reply-To: <CAPcyv4gVq=F-+8YX6ALUiL61MtOVtDzPrEo18WVsFodZ1YY20A@mail.gmail.com>
> Right, but how far away from "val = array[attacker_controlled_index];"
> in the instruction stream do you need to look before you're
> comfortable there's no 'val' dependent reads in the speculation window
> on all possible architectures. Until we have variable annotations and
> compiler help my guess is that static analysis has an easier time
> pointing us to the first potentially bad speculative access.
On x86 the researchers are saying up to 180 or so simple instructions.
I've not seen any Intel or AMD official quoted value. It's enough that
you need to peer across functions.
Alan
next prev parent reply other threads:[~2018-01-04 23:21 UTC|newest]
Thread overview: 82+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-03 22:38 [RFC PATCH 0/4] API for inhibiting speculative arbitrary read primitives Mark Rutland
2018-01-03 22:38 ` [RFC PATCH 1/4] asm-generic/barrier: add generic nospec helpers Mark Rutland
2018-01-03 22:38 ` Mark Rutland
2018-01-04 12:00 ` Mark Rutland
2018-01-05 4:21 ` Dan Williams
2018-01-05 9:15 ` Mark Rutland
2018-01-03 22:38 ` [RFC PATCH 2/4] Documentation: document " Mark Rutland
2018-01-03 22:38 ` Mark Rutland
2018-01-03 22:38 ` [RFC PATCH 3/4] arm64: implement nospec_{load,ptr}() Mark Rutland
2018-01-03 22:38 ` Mark Rutland
2018-01-03 22:38 ` [RFC PATCH 4/4] bpf: inhibit speculated out-of-bounds pointers Mark Rutland
2018-01-03 22:38 ` Mark Rutland
2018-01-03 23:45 ` Peter Zijlstra
2018-01-03 23:45 ` Peter Zijlstra
2018-01-04 10:59 ` Mark Rutland
2018-01-04 0:15 ` [RFC PATCH] asm/generic: introduce if_nospec and nospec_barrier Dan Williams
2018-01-04 0:15 ` Dan Williams
2018-01-04 0:39 ` Linus Torvalds
2018-01-04 1:07 ` Alan Cox
2018-01-04 1:13 ` Dan Williams
2018-01-04 1:13 ` Dan Williams
2018-01-04 6:28 ` Julia Lawall
2018-01-04 17:58 ` Dan Williams
2018-01-04 19:26 ` Pavel Machek
2018-01-04 19:26 ` Pavel Machek
2018-01-04 21:43 ` Dan Williams
2018-01-04 22:20 ` Linus Torvalds
2018-01-04 22:23 ` Linus Torvalds
2018-01-04 22:55 ` Alan Cox
2018-01-04 23:06 ` Linus Torvalds
2018-01-04 23:11 ` Alan Cox
2018-01-04 23:11 ` Alan Cox
2018-01-05 0:24 ` Dan Williams
2018-01-04 22:44 ` Pavel Machek
2018-01-04 23:12 ` Dan Williams
2018-01-04 23:12 ` Dan Williams
2018-01-04 23:21 ` Alan Cox [this message]
2018-01-04 23:33 ` Pavel Machek
2018-01-05 8:11 ` Julia Lawall
2018-01-04 1:27 ` Jiri Kosina
2018-01-04 1:27 ` Jiri Kosina
2018-01-04 1:41 ` Alan Cox
2018-01-04 1:47 ` Jiri Kosina
2018-01-04 1:47 ` Jiri Kosina
2018-01-04 19:39 ` Pavel Machek
2018-01-04 20:32 ` Alan Cox
2018-01-04 20:32 ` Alan Cox
2018-01-04 20:39 ` Jiri Kosina
2018-01-04 21:23 ` Alan Cox
2018-01-04 21:23 ` Alan Cox
2018-01-04 21:48 ` Pavel Machek
2018-01-04 1:51 ` Dan Williams
2018-01-04 1:51 ` Dan Williams
2018-01-04 1:54 ` Linus Torvalds
2018-01-04 1:54 ` Linus Torvalds
2018-01-04 3:10 ` Williams, Dan J
2018-01-04 4:44 ` Al Viro
2018-01-04 5:44 ` Dan Williams
2018-01-04 5:49 ` Dave Hansen
2018-01-04 5:49 ` Dave Hansen
2018-01-04 5:50 ` Al Viro
2018-01-04 5:55 ` Al Viro
2018-01-04 6:42 ` Dan Williams
2018-01-04 5:01 ` Eric W. Biederman
2018-01-04 6:32 ` Dan Williams
2018-01-04 14:54 ` Eric W. Biederman
2018-01-04 16:39 ` Mark Rutland
2018-01-04 20:56 ` Pavel Machek
2018-01-04 20:56 ` Pavel Machek
2018-01-04 11:47 ` Mark Rutland
2018-01-04 11:47 ` Mark Rutland
2018-01-04 22:09 ` Dan Williams
2018-01-05 14:40 ` Mark Rutland
2018-01-05 16:44 ` Dan Williams
2018-01-05 18:05 ` Dan Williams
2018-01-04 1:59 ` Jiri Kosina
2018-01-04 1:59 ` Jiri Kosina
2018-01-04 2:15 ` Alan Cox
2018-01-04 3:12 ` Alexei Starovoitov
2018-01-04 9:16 ` Reshetova, Elena
2018-01-04 9:16 ` Reshetova, Elena
2018-01-04 20:40 ` Pavel Machek
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