From: Borislav Petkov <bp@alien8.de>
To: Andy Lutomirski <luto@amacapital.net>
Cc: x86@kernel.org, Linus Torvalds <torvalds@linux-foundation.org>,
linux-kernel@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>,
Oleg Nesterov <oleg@redhat.com>, Tony Luck <tony.luck@intel.com>,
Andi Kleen <andi@firstfloor.org>
Subject: Re: [PATCH v4 3/5] x86, entry: Switch stacks on a paranoid entry from userspace
Date: Mon, 24 Nov 2014 16:55:13 +0100 [thread overview]
Message-ID: <20141124155512.GD20296@pd.tnic> (raw)
In-Reply-To: <955e71b4b8427aec7e8b86de0bf877e7944ba1f3.1416604491.git.luto@amacapital.net>
On Fri, Nov 21, 2014 at 01:26:09PM -0800, Andy Lutomirski wrote:
> This causes all non-NMI, non-double-fault kernel entries from
> userspace to run on the normal kernel stack. Double-fault is
> exempt to minimize confusion if we double-fault directly from
> userspace due to a bad kernel stack.
>
> This is, suprisingly, simpler and shorter than the current code. It
> removes the IMO rather frightening paranoid_userspace path, and it
> make sync_regs much simpler.
>
> There is no risk of stack overflow due to this change -- the kernel
> stack that we switch to is empty.
>
> This will also enable us to create non-atomic sections within
> machine checks from userspace, which will simplify memory failure
> handling. It will also allow the upcoming fsgsbase code to be
> simplified, because it doesn't need to worry about usergs when
> scheduling in paranoid_exit, as that code no longer exists.
>
> Cc: Oleg Nesterov <oleg@redhat.com>
> Cc: Andi Kleen <andi@firstfloor.org>
> Cc: Tony Luck <tony.luck@intel.com>
> Cc: Borislav Petkov <bp@alien8.de>
> Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Acked-by: Borislav Petkov <bp@suse.de>
--
Regards/Gruss,
Boris.
Sent from a fat crate under my desk. Formatting is fine.
--
next prev parent reply other threads:[~2014-11-24 15:55 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-21 21:26 [PATCH v4 0/5] x86: Rework IST interrupts Andy Lutomirski
2014-11-21 21:26 ` [PATCH v4 1/5] uprobes, x86: Fix _TIF_UPROBE vs _TIF_NOTIFY_RESUME Andy Lutomirski
2014-11-22 16:55 ` Borislav Petkov
2014-11-24 17:58 ` Andy Lutomirski
2014-11-21 21:26 ` [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context Andy Lutomirski
2014-11-21 21:32 ` Andy Lutomirski
2014-11-21 22:07 ` Paul E. McKenney
2014-11-21 22:19 ` Andy Lutomirski
2014-11-21 22:55 ` Paul E. McKenney
2014-11-21 23:06 ` Andy Lutomirski
2014-11-21 23:38 ` Paul E. McKenney
2014-11-22 2:00 ` Andy Lutomirski
2014-11-22 4:20 ` Paul E. McKenney
2014-11-22 5:53 ` Andy Lutomirski
2014-11-22 23:41 ` Paul E. McKenney
2014-11-24 20:22 ` Andy Lutomirski
2014-11-24 20:54 ` Paul E. McKenney
2014-11-24 21:02 ` Andy Lutomirski
2014-11-24 21:35 ` Paul E. McKenney
2014-11-24 22:34 ` Paul E. McKenney
2014-11-24 22:36 ` Andy Lutomirski
2014-11-24 22:57 ` Paul E. McKenney
2014-11-24 23:31 ` Paul E. McKenney
2014-11-24 23:35 ` Andy Lutomirski
2014-11-24 23:50 ` Paul E. McKenney
2014-11-24 23:52 ` Andy Lutomirski
2014-11-25 18:58 ` Borislav Petkov
2014-11-25 19:16 ` Paul E. McKenney
2014-12-11 0:22 ` Tony Luck
2014-12-11 0:24 ` Andy Lutomirski
2015-01-05 21:46 ` Tony Luck
2015-01-05 21:54 ` Andy Lutomirski
2015-01-06 0:44 ` [PATCH] x86, mce: Get rid of TIF_MCE_NOTIFY and associated mce tricks Luck, Tony
2015-01-06 1:01 ` Andy Lutomirski
2015-01-06 18:00 ` Luck, Tony
2015-01-07 12:13 ` Borislav Petkov
2015-01-07 15:51 ` Andy Lutomirski
2015-01-07 15:58 ` Borislav Petkov
2015-01-07 16:12 ` Paul E. McKenney
2014-11-25 17:13 ` [PATCH v4 2/5] x86, traps: Track entry into and exit from IST context Paul E. McKenney
2014-11-27 7:03 ` Lai Jiangshan
2014-11-27 16:46 ` Paul E. McKenney
2014-11-24 21:27 ` Paul E. McKenney
2014-11-21 22:20 ` Frederic Weisbecker
2014-11-21 22:00 ` Paul E. McKenney
2014-11-22 17:20 ` Borislav Petkov
2014-11-24 19:48 ` Andy Lutomirski
2015-01-22 21:52 ` Sasha Levin
2015-01-23 17:58 ` Andy Lutomirski
2015-01-23 18:04 ` Borislav Petkov
2015-01-23 18:34 ` Andy Lutomirski
2015-01-23 20:48 ` Sasha Levin
2015-01-24 1:25 ` Andy Lutomirski
2015-01-28 16:33 ` Andy Lutomirski
2015-01-28 17:48 ` Paul E. McKenney
2015-01-28 21:02 ` Andy Lutomirski
2015-01-30 19:57 ` Sasha Levin
2015-01-31 1:28 ` Sasha Levin
2015-01-31 3:12 ` Andy Lutomirski
2015-01-31 12:50 ` Andy Lutomirski
2015-01-31 13:01 ` [PATCH] x86, traps: Fix ist_enter from userspace Andy Lutomirski
2015-01-31 15:09 ` Sasha Levin
2015-01-31 16:18 ` Paul E. McKenney
2015-02-01 2:17 ` Andy Lutomirski
2015-02-04 6:01 ` [tip:x86/asm] " tip-bot for Andy Lutomirski
2014-11-21 21:26 ` [PATCH v4 3/5] x86, entry: Switch stacks on a paranoid entry " Andy Lutomirski
2014-11-24 15:55 ` Borislav Petkov [this message]
2014-11-21 21:26 ` [PATCH v4 4/5] x86: Clean up current_stack_pointer Andy Lutomirski
2014-11-24 11:39 ` Borislav Petkov
2014-11-21 21:26 ` [PATCH v4 5/5] x86, traps: Add ist_begin_non_atomic and ist_end_non_atomic Andy Lutomirski
2014-11-24 15:54 ` Borislav Petkov
2014-11-24 19:52 ` Andy Lutomirski
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