From ea0a281d7a7e2595cb3dd13ccff7005ad9f00b44 Mon Sep 17 00:00:00 2001
From: Andy Lutomirski <luto@MIT.EDU>
Date: Mon, 23 May 2011 09:31:30 -0400
Subject: [PATCH] --- yaml --- r: 251984 b: refs/heads/master c:
 f144a6b4d1688675d88990e29567b2335b48205e h: refs/heads/master v: v3

---
 [refs]                               |  2 +-
 trunk/arch/x86/vdso/vclock_gettime.c | 35 +++++++++++++++++++++++++++-
 trunk/arch/x86/vdso/vdso.lds.S       |  2 ++
 3 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/[refs] b/[refs]
index 5bb20412fbfa..ae7554b1cfbd 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 6447facba36e3fff77ab4c68f46297a5dab024c8
+refs/heads/master: f144a6b4d1688675d88990e29567b2335b48205e
diff --git a/trunk/arch/x86/vdso/vclock_gettime.c b/trunk/arch/x86/vdso/vclock_gettime.c
index 28b2c00bd1be..e6e9f90a8cd7 100644
--- a/trunk/arch/x86/vdso/vclock_gettime.c
+++ b/trunk/arch/x86/vdso/vclock_gettime.c
@@ -2,7 +2,7 @@
  * Copyright 2006 Andi Kleen, SUSE Labs.
  * Subject to the GNU Public License, v.2
  *
- * Fast user context implementation of clock_gettime and gettimeofday.
+ * Fast user context implementation of clock_gettime, gettimeofday, and time.
  *
  * The code should have no internal unresolved relocations.
  * Check with readelf after changing.
@@ -160,3 +160,36 @@ notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
 }
 int gettimeofday(struct timeval *, struct timezone *)
 	__attribute__((weak, alias("__vdso_gettimeofday")));
+
+/* This will break when the xtime seconds get inaccurate, but that is
+ * unlikely */
+
+static __always_inline long time_syscall(long *t)
+{
+	long secs;
+	asm volatile("syscall"
+		     : "=a" (secs)
+		     : "0" (__NR_time), "D" (t) : "cc", "r11", "cx", "memory");
+	return secs;
+}
+
+notrace time_t __vdso_time(time_t *t)
+{
+	unsigned seq;
+	time_t result;
+	if (unlikely(!VVAR(vsyscall_gtod_data).sysctl_enabled))
+		return time_syscall(t);
+
+	do {
+		seq = read_seqbegin(&VVAR(vsyscall_gtod_data).lock);
+
+		result = VVAR(vsyscall_gtod_data).wall_time_sec;
+
+	} while (read_seqretry(&VVAR(vsyscall_gtod_data).lock, seq));
+
+	if (t)
+		*t = result;
+	return result;
+}
+int time(time_t *t)
+	__attribute__((weak, alias("__vdso_time")));
diff --git a/trunk/arch/x86/vdso/vdso.lds.S b/trunk/arch/x86/vdso/vdso.lds.S
index 81f250011f71..b96b2677cad8 100644
--- a/trunk/arch/x86/vdso/vdso.lds.S
+++ b/trunk/arch/x86/vdso/vdso.lds.S
@@ -23,6 +23,8 @@ VERSION {
 		__vdso_gettimeofday;
 		getcpu;
 		__vdso_getcpu;
+		time;
+		__vdso_time;
 	local: *;
 	};
 }