[PATCH -tip 0/4] Text edit lock and atomic text_poke()

From: Masami Hiramatsu
Date: Fri Mar 06 2009 - 10:35:28 EST


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@xxxxxxxxxx

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