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Subject[tip:timers/clocksource] powerpc: Simplify update_vsyscall
Commit-ID:  b0797b60d0067fe437baa97a743c7d9de98fd769
Gitweb: http://git.kernel.org/tip/b0797b60d0067fe437baa97a743c7d9de98fd769
Author: John Stultz <johnstul@us.ibm.com>
AuthorDate: Tue, 13 Jul 2010 17:56:21 -0700
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Tue, 27 Jul 2010 12:40:54 +0200

powerpc: Simplify update_vsyscall

Currently powerpc's update_vsyscall calls an inline update_gtod.
However, both are straightforward, and there are no other users,
so this patch merges update_gtod into update_vsyscall.

Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1279068988-21864-5-git-send-email-johnstul@us.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/powerpc/kernel/time.c | 55 ++++++++++++++++++++------------------------
1 files changed, 25 insertions(+), 30 deletions(-)
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 0441bbd..6fcd648 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -423,30 +423,6 @@ void udelay(unsigned long usecs)
}
EXPORT_SYMBOL(udelay);

-static inline void update_gtod(u64 new_tb_stamp, u64 new_stamp_xsec,
- u64 new_tb_to_xs)
-{
- /*
- * tb_update_count is used to allow the userspace gettimeofday code
- * to assure itself that it sees a consistent view of the tb_to_xs and
- * stamp_xsec variables. It reads the tb_update_count, then reads
- * tb_to_xs and stamp_xsec and then reads tb_update_count again. If
- * the two values of tb_update_count match and are even then the
- * tb_to_xs and stamp_xsec values are consistent. If not, then it
- * loops back and reads them again until this criteria is met.
- * We expect the caller to have done the first increment of
- * vdso_data->tb_update_count already.
- */
- vdso_data->tb_orig_stamp = new_tb_stamp;
- vdso_data->stamp_xsec = new_stamp_xsec;
- vdso_data->tb_to_xs = new_tb_to_xs;
- vdso_data->wtom_clock_sec = wall_to_monotonic.tv_sec;
- vdso_data->wtom_clock_nsec = wall_to_monotonic.tv_nsec;
- vdso_data->stamp_xtime = xtime;
- smp_wmb();
- ++(vdso_data->tb_update_count);
-}
-
#ifdef CONFIG_SMP
unsigned long profile_pc(struct pt_regs *regs)
{
@@ -876,7 +852,7 @@ static cycle_t timebase_read(struct clocksource *cs)
void update_vsyscall(struct timespec *wall_time, struct clocksource *clock,
u32 mult)
{
- u64 t2x, stamp_xsec;
+ u64 new_tb_to_xs, new_stamp_xsec;

if (clock != &clocksource_timebase)
return;
@@ -887,11 +863,30 @@ void update_vsyscall(struct timespec *wall_time, struct clocksource *clock,

/* XXX this assumes clock->shift == 22 */
/* 4611686018 ~= 2^(20+64-22) / 1e9 */
- t2x = (u64) mult * 4611686018ULL;
- stamp_xsec = (u64) xtime.tv_nsec * XSEC_PER_SEC;
- do_div(stamp_xsec, 1000000000);
- stamp_xsec += (u64) xtime.tv_sec * XSEC_PER_SEC;
- update_gtod(clock->cycle_last, stamp_xsec, t2x);
+ new_tb_to_xs = (u64) mult * 4611686018ULL;
+ new_stamp_xsec = (u64) xtime.tv_nsec * XSEC_PER_SEC;
+ do_div(new_stamp_xsec, 1000000000);
+ new_stamp_xsec += (u64) xtime.tv_sec * XSEC_PER_SEC;
+
+ /*
+ * tb_update_count is used to allow the userspace gettimeofday code
+ * to assure itself that it sees a consistent view of the tb_to_xs and
+ * stamp_xsec variables. It reads the tb_update_count, then reads
+ * tb_to_xs and stamp_xsec and then reads tb_update_count again. If
+ * the two values of tb_update_count match and are even then the
+ * tb_to_xs and stamp_xsec values are consistent. If not, then it
+ * loops back and reads them again until this criteria is met.
+ * We expect the caller to have done the first increment of
+ * vdso_data->tb_update_count already.
+ */
+ vdso_data->tb_orig_stamp = clock->cycle_last;
+ vdso_data->stamp_xsec = new_stamp_xsec;
+ vdso_data->tb_to_xs = new_tb_to_xs;
+ vdso_data->wtom_clock_sec = wall_to_monotonic.tv_sec;
+ vdso_data->wtom_clock_nsec = wall_to_monotonic.tv_nsec;
+ vdso_data->stamp_xtime = xtime;
+ smp_wmb();
+ ++(vdso_data->tb_update_count);
}

void update_vsyscall_tz(void)

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