[FS#1496] can not enable /dev/mem by "make kernel_menuconfig"

[LEDE Bugs]

A new Flyspray task has been opened.  Details are below. 

User who did this - Qin Wei (Vonger) 

Attached to Project - OpenWrt/LEDE Project
Summary - can not enable /dev/mem by "make kernel_menuconfig"
Task Type - Bug Report
Category - Base system
Status - Unconfirmed
Assigned To - 
Operating System - All
Severity - Medium
Priority - Very Low
Reported Version - Trunk
Due in Version - Undecided
Due Date - Undecided
Details -  - Device problem occurs on
all ramips device, other device might effect too, but I can not test.

 - Software versions of OpenWrt/LEDE release, packages, etc.
Truck, my test from Linux 4.9 to 4.14

 - Steps to reproduce
 make kernel_menuconfig, select Device Drivers -> Character devices -> /dev/mem virtual device support
then make the firmware, upgrade to device, there is no file node /dev/mem.

If I directly hack the kernel, modify kernel/driver/char/mem.c, remove macro CONFIG_DEVMEM, /dev/mem will appear on firmware.

 

More information can be found at the following URL:
https://bugs.openwrt.org/index.php?do=details&task_id=1496