On Thu, 2011-11-24 at 17:07 +1100, Anton Blanchard wrote: > plain text document attachment (clock3) > Use clocksource_register_hz which calculates the shift/mult > factors for us. Also remove the shift = 22 assumption in > vsyscall_update - thanks to Paul Mackerras and John Stultz for > catching that. > > Signed-off-by: Anton Blanchard <an...@samba.org> > --- > > Index: linux-build/arch/powerpc/kernel/time.c > =================================================================== > --- linux-build.orig/arch/powerpc/kernel/time.c 2011-11-17 > 10:11:51.175038860 +1100 > +++ linux-build/arch/powerpc/kernel/time.c 2011-11-17 10:11:55.547114957 > +1100 > @@ -86,8 +86,6 @@ static struct clocksource clocksource_rt > .rating = 400, > .flags = CLOCK_SOURCE_IS_CONTINUOUS, > .mask = CLOCKSOURCE_MASK(64), > - .shift = 22, > - .mult = 0, /* To be filled in */ > .read = rtc_read, > }; > > @@ -97,8 +95,6 @@ static struct clocksource clocksource_ti > .rating = 400, > .flags = CLOCK_SOURCE_IS_CONTINUOUS, > .mask = CLOCKSOURCE_MASK(64), > - .shift = 22, > - .mult = 0, /* To be filled in */ > .read = timebase_read, > }; > > @@ -822,9 +818,8 @@ void update_vsyscall(struct timespec *wa > ++vdso_data->tb_update_count; > smp_mb(); > > - /* XXX this assumes clock->shift == 22 */ > - /* 4611686018 ~= 2^(20+64-22) / 1e9 */ > - new_tb_to_xs = (u64) mult * 4611686018ULL; > + /* 19342813113834067 ~= 2^(20+64) / 1e9 */ > + new_tb_to_xs = (u64) mult * (19342813113834067ULL >> clock->shift);
I never verified the math on this, but assuming Paul had it right, this patch looks good! Acked-by: John Stultz <johns...@us.ibm.com> Thanks again! -john _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
