From: Mark Rutland <mark.rutland@arm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Mathias Krause <minipli@googlemail.com>,
Thomas Gleixner <tglx@linutronix.de>,
Andy Lutomirski <luto@amacapital.net>,
Kees Cook <keescook@chromium.org>,
Andy Lutomirski <luto@kernel.org>,
"kernel-hardening@lists.openwall.com"
<kernel-hardening@lists.openwall.com>,
Hoeun Ryu <hoeun.ryu@gmail.com>, PaX Team <pageexec@freemail.hu>,
Emese Revfy <re.emese@gmail.com>,
Russell King <linux@armlinux.org.uk>, X86 ML <x86@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [kernel-hardening] Re: [RFC v2][PATCH 04/11] x86: Implement __arch_rare_write_begin/unmap()
Date: Mon, 10 Apr 2017 11:29:39 +0100 [thread overview]
Message-ID: <20170410102938.GB13899@leverpostej> (raw)
In-Reply-To: <20170407144526.zxgvpnxt6n7twhqw@hirez.programming.kicks-ass.net>
On Fri, Apr 07, 2017 at 04:45:26PM +0200, Peter Zijlstra wrote:
> On Fri, Apr 07, 2017 at 12:51:15PM +0200, Mathias Krause wrote:
> > Why that? It allows fast and CPU local modifications of r/o memory.
> > OTOH, an approach that needs to fiddle with page table entries
> > requires global synchronization to keep the individual TLB states in
> > sync. Hmm.. Not that fast, I'd say.
>
> The fixmaps used for kmap_atomic are per-cpu, no global sync required.
That might be fine for x86, but for some architectures fixmap slots and
kmap_atomic mappings happen to be visible to other CPUs even if they're
not required to be.
Using an mm solves that for all, though.
Thanks,
Mark.
next prev parent reply other threads:[~2017-04-10 10:30 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-29 18:15 [RFC v2] Introduce rare_write() infrastructure Kees Cook
2017-03-29 18:15 ` [RFC v2][PATCH 01/11] " Kees Cook
2017-03-29 18:23 ` Kees Cook
2017-03-30 7:44 ` Ho-Eun Ryu
2017-03-30 17:02 ` Kees Cook
2017-04-07 8:09 ` Ho-Eun Ryu
2017-04-07 20:38 ` Kees Cook
2017-03-29 18:15 ` [RFC v2][PATCH 02/11] lkdtm: add test for " Kees Cook
2017-03-30 9:34 ` [kernel-hardening] " Ian Campbell
2017-03-30 16:16 ` Kees Cook
2017-03-29 18:15 ` [RFC v2][PATCH 03/11] net: switch sock_diag handlers to rare_write() Kees Cook
2017-03-29 18:15 ` [RFC v2][PATCH 04/11] x86: Implement __arch_rare_write_begin/unmap() Kees Cook
2017-03-29 22:38 ` Andy Lutomirski
2017-03-30 1:41 ` Kees Cook
2017-04-05 23:57 ` Andy Lutomirski
2017-04-06 0:14 ` Kees Cook
2017-04-06 15:59 ` Andy Lutomirski
2017-04-07 8:34 ` [kernel-hardening] " Mathias Krause
2017-04-07 9:46 ` Thomas Gleixner
2017-04-07 10:51 ` Mathias Krause
2017-04-07 13:14 ` Thomas Gleixner
2017-04-07 13:30 ` Mathias Krause
2017-04-07 16:14 ` Andy Lutomirski
2017-04-07 16:22 ` Mark Rutland
2017-04-07 19:58 ` PaX Team
2017-04-08 4:58 ` Andy Lutomirski
2017-04-09 12:47 ` PaX Team
2017-04-10 0:10 ` Andy Lutomirski
2017-04-10 10:42 ` PaX Team
2017-04-10 16:01 ` Andy Lutomirski
2017-04-07 20:44 ` Thomas Gleixner
2017-04-07 21:20 ` Kees Cook
2017-04-08 4:12 ` Daniel Micay
2017-04-08 4:13 ` Daniel Micay
2017-04-08 4:21 ` Daniel Micay
2017-04-08 5:07 ` Andy Lutomirski
2017-04-08 7:33 ` Daniel Micay
2017-04-08 15:20 ` Andy Lutomirski
2017-04-09 10:53 ` Ingo Molnar
2017-04-10 10:22 ` Mark Rutland
2017-04-09 20:24 ` PaX Team
2017-04-10 0:31 ` Andy Lutomirski
2017-04-10 19:47 ` PaX Team
2017-04-10 20:27 ` Andy Lutomirski
2017-04-10 20:13 ` Kees Cook
2017-04-10 20:17 ` Andy Lutomirski
2017-04-07 19:25 ` Thomas Gleixner
2017-04-07 14:45 ` Peter Zijlstra
2017-04-10 10:29 ` Mark Rutland [this message]
2017-04-07 19:52 ` PaX Team
2017-04-10 8:26 ` Thomas Gleixner
2017-04-10 19:55 ` PaX Team
2017-04-07 9:37 ` Peter Zijlstra
2017-03-29 18:15 ` [RFC v2][PATCH 05/11] ARM: mm: dump: Add domain to output Kees Cook
2017-03-29 18:15 ` [RFC v2][PATCH 06/11] ARM: domains: Extract common USER domain init Kees Cook
2017-03-29 18:15 ` [RFC v2][PATCH 07/11] ARM: mm: set DOMAIN_WR_RARE for rodata Kees Cook
2017-03-29 18:16 ` [RFC v2][PATCH 08/11] ARM: Implement __arch_rare_write_begin/end() Kees Cook
2017-04-07 9:36 ` Peter Zijlstra
2017-03-29 18:16 ` [RFC v2][PATCH 09/11] list: add rare_write() list helpers Kees Cook
2017-03-29 18:16 ` [RFC v2][PATCH 10/11] gcc-plugins: Add constify plugin Kees Cook
2017-03-29 18:16 ` [RFC v2][PATCH 11/11] cgroups: force all struct cftype const Kees Cook
2017-03-29 19:00 ` [RFC v2] Introduce rare_write() infrastructure Russell King - ARM Linux
2017-03-29 19:14 ` Kees Cook
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