time: Introduce CLOCK_REALTIME_COARSE

[safe/jmp/linux-2.6] / arch / x86 / vdso / vclock_gettime.c

diff --git a/arch/x86/vdso/vclock_gettime.c b/arch/x86/vdso/vclock_gettime.c
index 1ef0f90..ee55754 100644 (file)
--- a/arch/x86/vdso/vclock_gettime.c
+++ b/arch/x86/vdso/vclock_gettime.c
@@ -9,6 +9,9 @@
  * Also alternative() doesn't work.
  */
 
+/* Disable profiling for userspace code: */
+#define DISABLE_BRANCH_PROFILING
+
 #include <linux/kernel.h>
 #include <linux/posix-timers.h>
 #include <linux/time.h>
@@ -83,14 +86,47 @@ notrace static noinline int do_monotonic(struct timespec *ts)
        return 0;
 }
 
+notrace static noinline int do_realtime_coarse(struct timespec *ts)
+{
+       unsigned long seq;
+       do {
+               seq = read_seqbegin(&gtod->lock);
+               ts->tv_sec = gtod->wall_time_coarse.tv_sec;
+               ts->tv_nsec = gtod->wall_time_coarse.tv_nsec;
+       } while (unlikely(read_seqretry(&gtod->lock, seq)));
+       return 0;
+}
+
+notrace static noinline int do_monotonic_coarse(struct timespec *ts)
+{
+       unsigned long seq, ns, secs;
+       do {
+               seq = read_seqbegin(&gtod->lock);
+               secs = gtod->wall_time_coarse.tv_sec;
+               ns = gtod->wall_time_coarse.tv_nsec;
+               secs += gtod->wall_to_monotonic.tv_sec;
+               ns += gtod->wall_to_monotonic.tv_nsec;
+       } while (unlikely(read_seqretry(&gtod->lock, seq)));
+       vset_normalized_timespec(ts, secs, ns);
+       return 0;
+}
+
 notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
 {
-       if (likely(gtod->sysctl_enabled && gtod->clock.vread))
+       if (likely(gtod->sysctl_enabled))
                switch (clock) {
                case CLOCK_REALTIME:
-                       return do_realtime(ts);
+                       if (likely(gtod->clock.vread))
+                               return do_realtime(ts);
+                       break;
                case CLOCK_MONOTONIC:
-                       return do_monotonic(ts);
+                       if (likely(gtod->clock.vread))
+                               return do_monotonic(ts);
+                       break;
+               case CLOCK_REALTIME_COARSE:
+                       return do_realtime_coarse(ts);
+               case CLOCK_MONOTONIC_COARSE:
+                       return do_monotonic_coarse(ts);
                }
        return vdso_fallback_gettime(clock, ts);
 }
@@ -101,11 +137,13 @@ notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
 {
        long ret;
        if (likely(gtod->sysctl_enabled && gtod->clock.vread)) {
-               BUILD_BUG_ON(offsetof(struct timeval, tv_usec) !=
-                            offsetof(struct timespec, tv_nsec) ||
-                            sizeof(*tv) != sizeof(struct timespec));
-               do_realtime((struct timespec *)tv);
-               tv->tv_usec /= 1000;
+               if (likely(tv != NULL)) {
+                       BUILD_BUG_ON(offsetof(struct timeval, tv_usec) !=
+                                    offsetof(struct timespec, tv_nsec) ||
+                                    sizeof(*tv) != sizeof(struct timespec));
+                       do_realtime((struct timespec *)tv);
+                       tv->tv_usec /= 1000;
+               }
                if (unlikely(tz != NULL)) {
                        /* Avoid memcpy. Some old compilers fail to inline it */
                        tz->tz_minuteswest = gtod->sys_tz.tz_minuteswest;