[PATCH v2 6/8] RISC-V: Add required checks during clock source init

Atish Patra
2019-01-08T09:39:00Z

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@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..d9b914e9 100644
--- a/drivers/clocksource/timer-riscv.c
+++ b/drivers/clocksource/timer-riscv.c
@@ -95,14 +95,31 @@ 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