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authorAvi Kivity <avi@redhat.com>2009-09-19 09:40:22 +0300
committerH. Peter Anvin <hpa@zytor.com>2009-10-01 12:12:18 -0700
commit7c68af6e32c73992bad24107311f3433c89016e2 (patch)
tree9046ac5339f944e8ddccd34be226790b953dda61 /arch/x86/kernel/signal.c
parent817b33d38f81c8736d39283c35c886ae4668f1af (diff)
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>
Diffstat (limited to 'arch/x86/kernel/signal.c')
-rw-r--r--arch/x86/kernel/signal.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index 6a44a76055a..c49f90f7957 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -19,6 +19,7 @@
#include <linux/stddef.h>
#include <linux/personality.h>
#include <linux/uaccess.h>
+#include <linux/user-return-notifier.h>
#include <asm/processor.h>
#include <asm/ucontext.h>
@@ -872,6 +873,8 @@ do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
if (current->replacement_session_keyring)
key_replace_session_keyring();
}
+ if (thread_info_flags & _TIF_USER_RETURN_NOTIFY)
+ fire_user_return_notifiers();
#ifdef CONFIG_X86_32
clear_thread_flag(TIF_IRET);