lkml.org 
[lkml]   [2016]   [May]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] dell-smm-hwmon: In debug mode log duration of SMM calls
Date
This allow us to debug how long take each SMM call and how long is system
freezed in SMM handler.

Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
---
drivers/hwmon/dell-smm-hwmon.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)

diff --git a/drivers/hwmon/dell-smm-hwmon.c b/drivers/hwmon/dell-smm-hwmon.c
index 7a2764a..8a66a42 100644
--- a/drivers/hwmon/dell-smm-hwmon.c
+++ b/drivers/hwmon/dell-smm-hwmon.c
@@ -137,6 +137,14 @@ 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;
@@ -208,6 +216,15 @@ 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;
}

--
1.7.9.5
\
 
 \ /
  Last update: 2016-05-21 17:21    [W:0.031 / U:0.440 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site