thermal: add a warning for temperature emulation feature

Because this feature is for debuging purposes, it is highly
recommended to do not enable this on production systems.
This patch adds warnings for system integrators, so that
people are aware of this potential security issue.

Signed-off-by: Eduardo Valentin <eduardo.valentin@ti.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>

diff --git a/Documentation/thermal/sysfs-api.txt b/Documentation/thermal/sysfs-api.txt
index 6859661c9d31be090a78e5a2c35a9a5fdad7ca80..277530a5786c7a232c644e8c969692a8605bf5fe 100644 (file)
--- a/Documentation/thermal/sysfs-api.txt
+++ b/Documentation/thermal/sysfs-api.txt
@@ -265,6 +265,10 @@ emul_temp
        Unit: millidegree Celsius
        WO, Optional
 
+         WARNING: Be careful while enabling this option on production systems,
+         because userland can easily disable the thermal policy by simply
+         flooding this sysfs node with low temperature values.
+
 *****************************
 * Cooling device attributes *
 *****************************

diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
index 2a19120c32bdb7cacd373bb1c2b4ff36de7adeb5..fb0672baff40b165bfddb2fb83363a8ca6cdec5c 100644 (file)
--- a/drivers/thermal/Kconfig
+++ b/drivers/thermal/Kconfig
@@ -86,6 +86,10 @@ config THERMAL_EMULATION
          user can manually input temperature and test the different trip
          threshold behaviour for simulation purpose.
 
+         WARNING: Be careful while enabling this option on production systems,
+         because userland can easily disable the thermal policy by simply
+         flooding this sysfs node with low temperature values.
+
 config SPEAR_THERMAL
        bool "SPEAr thermal sensor driver"
        depends on PLAT_SPEAR