Re: [v4 PATCH 6/8] clocksource/drivers/riscv: Add required checks during clock source init

[Palmer Dabbelt]

On Wed, 13 Feb 2019 00:48:24 PST (-0800), daniel.lezcano@xxxxxxxxxx wrote:
> On 12/02/2019 12:10, Atish Patra wrote:
> > Currently, clocksource registration happens for an invalid cpu for
> > non-smp kernels. This lead to kernel panic as cpu hotplug registration
> > will fail for those cpus. Moreover, riscv_hartid_to_cpuid can return
> > errors now.
> >
> > Do not proceed if hartid or cpuid is invalid. Take this opprtunity to
> > print appropriate error strings for different failure cases.
> >
> > Signed-off-by: Atish Patra <atish.patra@xxxxxxx>
>
> Do you want me to take it through my tree ?

Works for me.  Aside from the typo:

Reviewed-by: Palmer Dabbelt <palmer@xxxxxxxxxx>

> > ---
> >  drivers/clocksource/timer-riscv.c | 23 ++++++++++++++++++++---
> >  1 file changed, 20 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/clocksource/timer-riscv.c b/drivers/clocksource/timer-riscv.c
> > index 43189220..e8163693 100644
> > --- a/drivers/clocksource/timer-riscv.c
> > +++ b/drivers/clocksource/timer-riscv.c
> > @@ -95,13 +95,30 @@ static int __init riscv_timer_init_dt(struct device_node *n)
> >  	struct clocksource *cs;
> >
> >  	hartid = riscv_of_processor_hartid(n);
> > +	if (hartid < 0) {
> > +		pr_warn("Not valid hartid for node [%pOF] error = [%d]\n",
> > +			n, hartid);
> > +		return hartid;
> > +	}
> > +
> >  	cpuid = riscv_hartid_to_cpuid(hartid);
> > +	if (cpuid < 0) {
> > +		pr_warn("Invalid cpuid for hartid [%d]\n", hartid);
> > +		return cpuid;
> > +	}
> >
> >  	if (cpuid != smp_processor_id())
> >  		return 0;
> >
> > +	pr_info("%s: Registering clocksource cpuid [%d] hartid [%d]\n",
> > +	       __func__, cpuid, hartid);

My only comment is that we flipped back and forth on whether or not to print 
info on driver initialization.  I like it because I have to go add the prints 
in to debug things, but IIRC we removed it at some point (probably more than 
once, as I have to keep adding these sorts of things back in and forget to 
remove them).

The review stands either way :)

> >  	cs = per_cpu_ptr(&riscv_clocksource, cpuid);
> > -	clocksource_register_hz(cs, riscv_timebase);
> > +	error = clocksource_register_hz(cs, riscv_timebase);
> > +	if (error) {
> > +		pr_err("RISCV timer register failed [%d] for cpu = [%d]\n",
> > +		       error, cpuid);
> > +		return error;
> > +	}
> >
> >  	sched_clock_register(riscv_sched_clock,
> >  			BITS_PER_LONG, riscv_timebase);
> > @@ -110,8 +127,8 @@ static int __init riscv_timer_init_dt(struct device_node *n)
> >  			 "clockevents/riscv/timer:starting",
> >  			 riscv_timer_starting_cpu, riscv_timer_dying_cpu);
> >  	if (error)
> > -		pr_err("RISCV timer register failed [%d] for cpu = [%d]\n",
> > -		       error, cpuid);
> > +		pr_err("cpu hp setup state failed for RISCV timer [%d]\n",
> > +		       error);
> >  	return error;
> >  }