[PATCH] ppc64: fix initialisation of gettimeofday calculations

[Stephen Rothwell <sfr@canb.auug.org.au>]

Hi Andrew,

On PPC64, we keep track of when we need to update jiffies (and the
variables used to calculate the time of day) based on the time base.  If
the time base frequence is sufficiently high compared to the processor
clock frequency, then it is possible for the time of day variables to be
corrupted by at the time of the first decrementer interrupt we take.  This
became obvious on a legacy iSeries where the time base frequency is the
same as the processor clock.  This one line patch fixes the initialisation
so that the time of day variables and the indicator we use to tell when
updates are due are better synchronised.

Signed-off-by:  Stephen Rothwell <sfr@canb.auug.org.au>

Please apply and send to Linus.
-- 
Cheers,
Stephen Rothwell                    sfr@canb.auug.org.au
http://www.canb.auug.org.au/~sfr/

diff -ruNp linus/arch/ppc64/kernel/time.c linus-clock.1/arch/ppc64/kernel/time.c
--- linus/arch/ppc64/kernel/time.c	2005-05-17 09:23:08.000000000 +1000
+++ linus-clock.1/arch/ppc64/kernel/time.c	2005-05-25 13:11:14.000000000 +1000
@@ -515,6 +515,7 @@ void __init time_init(void)
 	do_gtod.varp = &do_gtod.vars[0];
 	do_gtod.var_idx = 0;
 	do_gtod.varp->tb_orig_stamp = tb_last_stamp;
+	get_paca()->next_jiffy_update_tb = tb_last_stamp + tb_ticks_per_jiffy;
 	do_gtod.varp->stamp_xsec = xtime.tv_sec * XSEC_PER_SEC;
 	do_gtod.tb_ticks_per_sec = tb_ticks_per_sec;
 	do_gtod.varp->tb_to_xs = tb_to_xs;

Attachment: pgpQB9EWkheRN.pgp
Description: PGP signature