core, x86: Add user return notifiers
authorAvi Kivity <avi@redhat.com>
Sat, 19 Sep 2009 06:40:22 +0000 (09:40 +0300)
committerH. Peter Anvin <hpa@zytor.com>
Thu, 1 Oct 2009 19:12:18 +0000 (12:12 -0700)
commit7c68af6e32c73992bad24107311f3433c89016e2
tree9046ac5339f944e8ddccd34be226790b953dda61
parent817b33d38f81c8736d39283c35c886ae4668f1af
core, x86: Add user return notifiers

Add a general per-cpu notifier that is called whenever the kernel is
about to return to userspace.  The notifier uses a thread_info flag
and existing checks, so there is no impact on user return or context
switch fast paths.

This will be used initially to speed up KVM task switching by lazily
updating MSRs.

Signed-off-by: Avi Kivity <avi@redhat.com>
LKML-Reference: <1253342422-13811-1-git-send-email-avi@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
arch/Kconfig
arch/x86/Kconfig
arch/x86/include/asm/thread_info.h
arch/x86/kernel/process.c
arch/x86/kernel/signal.c
include/linux/user-return-notifier.h [new file with mode: 0644]
kernel/user-return-notifier.c [new file with mode: 0644]