clocksource/drivers/riscv: Add required checks during clock source init

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 opportunity to
print appropriate error strings for different failure cases.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

1 files changed, 20 insertions, 3 deletions

diff --git a/drivers/clocksource/timer-riscv.c b/drivers/clocksource/timer-riscv.c
index 431892200a08..e8163693e936 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);
         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;
 }