From: "Jon Medhurst (Tixy)" <tixy@linaro.org>
To: Will Deacon <will.deacon@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Russell King - ARM Linux <linux@arm.linux.org.uk>,
Frederic Weisbecker <fweisbec@gmail.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Rabin Vincent <rabin@rab.in>, Ingo Molnar <mingo@redhat.com>,
"H. Peter Anvin" <hpa@linux.intel.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] ARM: ftrace: Ensure code modifications are synchronised across all cpus
Date: Mon, 10 Dec 2012 11:04:05 +0000 [thread overview]
Message-ID: <1355137445.3386.7.camel@linaro1.home> (raw)
In-Reply-To: <20121207190244.GB29618@mudshark.cambridge.arm.com>
On Fri, 2012-12-07 at 19:02 +0000, Will Deacon wrote:
> For ARMv7, there are small subsets of instructions for ARM and Thumb which
> are guaranteed to be atomic wrt concurrent modification and execution of
> the instruction stream between different processors:
>
> Thumb: The 16-bit encodings of the B, NOP, BKPT, and SVC instructions.
> ARM: The B, BL, NOP, BKPT, SVC, HVC, and SMC instructions.
>
So this means for things like kprobes which can modify arbitrary kernel
code we are going to need to continue to always use some form of
stop_the_whole_system() function?
Also, kprobes currently uses patch_text() which only uses stop_machine
for Thumb2 instructions which straddle a word boundary, so this needs
changing?
--
Tixy
next prev parent reply other threads:[~2012-12-10 11:04 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-06 18:11 [PATCH] ARM: ftrace: Ensure code modifications are synchronised across all cpus Jon Medhurst (Tixy)
2012-12-06 19:19 ` Steven Rostedt
2012-12-07 9:22 ` Jon Medhurst (Tixy)
2012-12-07 14:03 ` Steven Rostedt
2012-12-07 14:55 ` Jon Medhurst (Tixy)
2012-12-07 15:28 ` Steven Rostedt
2012-12-07 15:40 ` Jon Medhurst (Tixy)
2012-12-07 16:09 ` Steven Rostedt
2012-12-07 16:23 ` Russell King - ARM Linux
2012-12-07 16:36 ` Steven Rostedt
2012-12-07 16:45 ` Russell King - ARM Linux
2012-12-07 17:13 ` Steven Rostedt
2012-12-07 17:45 ` Jon Medhurst (Tixy)
2012-12-07 18:06 ` Steven Rostedt
2012-12-07 18:17 ` Steven Rostedt
2012-12-07 18:18 ` Jon Medhurst (Tixy)
2012-12-10 10:04 ` Will Deacon
2012-12-10 13:02 ` Steven Rostedt
2012-12-10 13:33 ` Will Deacon
2012-12-10 13:40 ` Jamie Lokier
2012-12-10 14:56 ` Will Deacon
2012-12-10 13:57 ` Russell King - ARM Linux
2012-12-10 14:06 ` Steven Rostedt
2012-12-10 14:07 ` Russell King - ARM Linux
2012-12-10 14:46 ` Steven Rostedt
2012-12-10 15:25 ` Russell King - ARM Linux
2012-12-10 16:31 ` Steven Rostedt
2012-12-10 16:45 ` Jon Medhurst (Tixy)
2012-12-07 18:13 ` Russell King - ARM Linux
2012-12-07 18:43 ` Steven Rostedt
2012-12-07 19:02 ` Will Deacon
2012-12-07 20:01 ` Steven Rostedt
2012-12-10 11:04 ` Jon Medhurst (Tixy) [this message]
2012-12-10 11:24 ` Will Deacon
2012-12-10 14:02 ` Steven Rostedt
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