| Message ID | 20181001230105.26040-1-anton@ozlabs.org (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 8b78fdb045de60a4eb35460092bbd3cffa925353 |
| Headers | show |
| Series | [1/2] powerpc/time: Use clockevents_register_device(), fixing an issue with large decrementer | expand |
On Mon, 2018-10-01 at 23:01:04 UTC, Anton Blanchard wrote: > We currently cap the decrementer clockevent at 4 seconds, even on systems > with large decrementer support. Fix this by converting the code to use > clockevents_register_device() which calculates the upper bound based on > the max_delta passed in. > > Signed-off-by: Anton Blanchard <anton@ozlabs.org> Series applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/8b78fdb045de60a4eb35460092bbd3 cheers
Anton Blanchard <anton@ozlabs.org> writes: > diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c > index 70f145e02487..6a1f0a084ca3 100644 > --- a/arch/powerpc/kernel/time.c > +++ b/arch/powerpc/kernel/time.c > @@ -1035,18 +1035,7 @@ static void __init set_decrementer_max(void) > > static void __init init_decrementer_clockevent(void) > { > - int cpu = smp_processor_id(); > - > - clockevents_calc_mult_shift(&decrementer_clockevent, ppc_tb_freq, 4); > - > - decrementer_clockevent.max_delta_ns = > - clockevent_delta2ns(decrementer_max, &decrementer_clockevent); > - decrementer_clockevent.max_delta_ticks = decrementer_max; > - decrementer_clockevent.min_delta_ns = > - clockevent_delta2ns(2, &decrementer_clockevent); > - decrementer_clockevent.min_delta_ticks = 2; > - > - register_decrementer_clockevent(cpu); > + register_decrementer_clockevent(smp_processor_id()); > } This broke KVM PR :) Because we no longer set the mult/shift in decrementer_clockevent, which is used in kvmppc_emulate_dec(). The patch below fixes it, though it'd be nice to come up with something cleaner eventually. cheers diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c index 6a1f0a084ca3..d21b2b88c0a7 100644 --- a/arch/powerpc/kernel/time.c +++ b/arch/powerpc/kernel/time.c @@ -1036,6 +1036,9 @@ static void __init set_decrementer_max(void) static void __init init_decrementer_clockevent(void) { register_decrementer_clockevent(smp_processor_id()); + + /* Set values for KVM, see kvm_emulate_dec() */ + decrementer_clockevent = *dec; } void secondary_cpu_time_init(void)
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c index 70f145e02487..6a1f0a084ca3 100644 --- a/arch/powerpc/kernel/time.c +++ b/arch/powerpc/kernel/time.c @@ -984,10 +984,10 @@ static void register_decrementer_clockevent(int cpu) *dec = decrementer_clockevent; dec->cpumask = cpumask_of(cpu); + clockevents_config_and_register(dec, ppc_tb_freq, 2, decrementer_max); + printk_once(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n", dec->name, dec->mult, dec->shift, cpu); - - clockevents_register_device(dec); } static void enable_large_decrementer(void) @@ -1035,18 +1035,7 @@ static void __init set_decrementer_max(void) static void __init init_decrementer_clockevent(void) { - int cpu = smp_processor_id(); - - clockevents_calc_mult_shift(&decrementer_clockevent, ppc_tb_freq, 4); - - decrementer_clockevent.max_delta_ns = - clockevent_delta2ns(decrementer_max, &decrementer_clockevent); - decrementer_clockevent.max_delta_ticks = decrementer_max; - decrementer_clockevent.min_delta_ns = - clockevent_delta2ns(2, &decrementer_clockevent); - decrementer_clockevent.min_delta_ticks = 2; - - register_decrementer_clockevent(cpu); + register_decrementer_clockevent(smp_processor_id()); } void secondary_cpu_time_init(void)
We currently cap the decrementer clockevent at 4 seconds, even on systems with large decrementer support. Fix this by converting the code to use clockevents_register_device() which calculates the upper bound based on the max_delta passed in. Signed-off-by: Anton Blanchard <anton@ozlabs.org> --- arch/powerpc/kernel/time.c | 17 +++-------------- 1 file changed, 3 insertions(+), 14 deletions(-)