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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/process.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/process.c')
-rw-r--r--arch/x86/kernel/process.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 5284cd2b577..e51b056fc88 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -9,6 +9,7 @@
#include <linux/pm.h>
#include <linux/clockchips.h>
#include <linux/random.h>
+#include <linux/user-return-notifier.h>
#include <trace/events/power.h>
#include <asm/system.h>
#include <asm/apic.h>
@@ -224,6 +225,7 @@ void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p,
*/
memset(tss->io_bitmap, 0xff, prev->io_bitmap_max);
}
+ propagate_user_return_notify(prev_p, next_p);
}
int sys_fork(struct pt_regs *regs)