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hwmon: (dell-smm) In debug mode log duration of SMM calls

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This allow us to debug how long take each SMM call and how long is system
frozen in SMM handler.

Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Pali Rohár 2016-06-18 00:54:49 +02:00 committed by Guenter Roeck
parent 747bc8b063
commit 9d58bec096
1 changed files with 17 additions and 0 deletions
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17
drivers/hwmon/dell-smm-hwmon.c
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@ -140,6 +140,14 @@ static int i8k_smm(struct smm_regs *regs)
int eax = regs->eax;
cpumask_var_t old_mask;
#ifdef DEBUG
int ebx = regs->ebx;
unsigned long duration;
ktime_t calltime, delta, rettime;
calltime = ktime_get();
#endif
/* SMM requires CPU 0 */
if (!alloc_cpumask_var(&old_mask, GFP_KERNEL))
return -ENOMEM;
@ -211,6 +219,15 @@ static int i8k_smm(struct smm_regs *regs)
out:
set_cpus_allowed_ptr(current, old_mask);
free_cpumask_var(old_mask);
#ifdef DEBUG
rettime = ktime_get();
delta = ktime_sub(rettime, calltime);
duration = ktime_to_ns(delta) >> 10;
pr_debug("smm(0x%.4x 0x%.4x) = 0x%.4x (took %7lu usecs)\n", eax, ebx,
(rc ? 0xffff : regs->eax & 0xffff), duration);
#endif
return rc;
}