linux-kernel - [PATCH -tip 0/4] Text edit lock and atomic text

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Date:	Fri, 06 Mar 2009 10:34:34 -0500
From:	Masami Hiramatsu <mhiramat@...hat.com>
To:	Mathieu Desnoyers <mathieu.desnoyers@...ymtl.ca>,
	Ingo Molnar <mingo@...e.hu>
CC:	Andrew Morton <akpm@...ux-foundation.org>,
	Nick Piggin <npiggin@...e.de>,
	Steven Rostedt <rostedt@...dmis.org>,
	Andi Kleen <andi@...stfloor.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Peter Zijlstra <peterz@...radead.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Arjan van de Ven <arjan@...radead.org>,
	Rusty Russell <rusty@...tcorp.com.au>,
	"H. Peter Anvin" <hpa@...or.com>
Subject: [PATCH -tip 0/4] Text edit lock and atomic text_poke()

Hi,

Here is a series of patches which introduce text_mutex for protecting
editing kernel text from each other subsystems, and make text_poke()
atomic by using fixmap.

BTW,

> Paravirt and alternatives are always done when SMP is inactive, so there is no
> need to use locks.

Mathieu, I'm not sure that means. alternatives will be called from module
init code and other place where the system has already been running multi-
-threads(and they use smp_alt mutex). So, is it possible that those functions
will sleep or yield to another process?

Anyway, I added a new patch which locks text_mutex in alternative_smp_*.

Thank you,

 arch/x86/include/asm/fixmap.h |    2 ++
 arch/x86/kernel/alternative.c |   29 ++++++++++++++++++++---------
 include/linux/memory.h        |    6 ++++++
 kernel/kprobes.c              |   15 +++++++++++++--
 mm/memory.c                   |    9 +++++++++
 5 files changed, 50 insertions(+), 11 deletions(-)

-- 
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America) Inc.
Software Solutions Division

e-mail: mhiramat@...hat.com

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