[v3 PATCH 6/8] clocksource/drivers/riscv: Add required checks during clock source init

[Atish Patra]

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>
---
 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..3c7ea75b 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_err("%s: Registering clocksource cpuid [%d] hartid [%d]\n",
+              __func__, cpuid, hartid);
        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;
 }
 
-- 
2.7.4