On Wed, 13 Feb 2019 00:48:24 PST (-0800), daniel.lezc...@linaro.org 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.pa...@wdc.com>

Do you want me to take it through my tree ?

Works for me.  Aside from the typo:

Reviewed-by: Palmer Dabbelt <pal...@sifive.com>



---
 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;
 }


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