On 06/01/2016 03:04 AM, Borislav Petkov wrote:
From: Borislav Petkov <bp@xxxxxxx>
We need to read a bunch of registers on each compute unit and possibly
on the current CPU too. Disable preemption around it.
An explanation would be helpful. Is this a bug fix ? I would like to get
a confirmation from someone at AMD that this is really necessary.
Thanks,
Guenter
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Cc: Rui Huang <ray.huang@xxxxxxx>
Cc: Sherry Hurwitz <sherry.hurwitz@xxxxxxx>
Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
---
drivers/hwmon/fam15h_power.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/drivers/hwmon/fam15h_power.c b/drivers/hwmon/fam15h_power.c
index eb97a9241d17..69bb810f528b 100644
--- a/drivers/hwmon/fam15h_power.c
+++ b/drivers/hwmon/fam15h_power.c
@@ -172,9 +172,9 @@ static void do_read_registers_on_cu(void *_data)
*/
static int read_registers(struct fam15h_power_data *data)
{
- int this_cpu, ret, cpu;
int core, this_core;
cpumask_var_t mask;
+ int ret, cpu;
ret = zalloc_cpumask_var(&mask, GFP_KERNEL);
if (!ret)
@@ -183,7 +183,6 @@ static int read_registers(struct fam15h_power_data *data)
memset(data->cu_on, 0, sizeof(int) * MAX_CUS);
get_online_cpus();
- this_cpu = smp_processor_id();
/*
* Choose the first online core of each compute unit, and then
@@ -205,10 +204,13 @@ static int read_registers(struct fam15h_power_data *data)
cpumask_set_cpu(cpumask_any(topology_sibling_cpumask(cpu)), mask);
}
- if (cpumask_test_cpu(this_cpu, mask))
+ preempt_disable();
+ smp_call_function_many(mask, do_read_registers_on_cu, data, true);
+
+ if (cpumask_test_cpu(smp_processor_id(), mask))
do_read_registers_on_cu(data);
- smp_call_function_many(mask, do_read_registers_on_cu, data, true);
+ preempt_enable();
put_online_cpus();
free_cpumask_var(mask);
--
To unsubscribe from this list: send the line "unsubscribe linux-hwmon" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
