android kernel build (first time)

Question

Ok so first off, Im brand new to android dev. This is my first attempt at any form of kernel anything. I have a limited knowledge of java and python, but no C.

I have a galaxy tab 4 sm-t330nu running 4.4.2. its running a qualcomm snapdragon 400 msm8226 cpu. im simply trying to do a test build with a vanilla kernel at this point. (also my build environment is the newest kali 1.1 and im loosely following the tutorial at https://github.com/offensive-security/kali-nethunter/wiki/Porting-Nethunter)

so i have all of the required dependencies (i hope), and ive downloaded my source from samsung opensource. unzipped and went through the available defconfigs. after finding "msm8226-sec_milletwifiue_defconfig" i decided it was the most likely candidate for my tablet. (when doing a custom recovery i remember it being "philz touch milletwifiue something)

Ive done my exports (arch= subarch= cross_compile=) and all seems well. When i run a build following exactly as the tutorial says (using the defconfig in their example as a test) i receive an error stating "must define variant_defconfig". So i instead do "make variant_defconfig=msm8974_sec_defconfig" and it builds great.

Now the issue: When i change "msm8974_sec_defconfig" to my actual msm8226 i receive an error on every build that i cannot seem to workaround. (cut down for size)

CC      arch/arm/kernel/armksyms.o
CC      arch/arm/kernel/module.o
AS      arch/arm/kernel/sleep.o
CC      arch/arm/kernel/suspend.o
CC      arch/arm/kernel/io.o
arch/arm/kernel/io.c: In function '_memcpy_fromio':
arch/arm/kernel/io.c:14:3: error: implicit declaration of function 'nop'     [-Werror=implicit-function-declaration]
cc1: some warnings being treated as errors
make[1]: *** [arch/arm/kernel/io.o] Error 1
make: *** [arch/arm/kernel] Error 2

My exact bash line reads

make VARIANT_DEFCONFIG=msm8226-sec_milletwifiue_defconfig

Any assistance on clearing this up would be great

edit
although im not familiar with c, it seems to me that '_memcpy_fromio' is where the error lies. and my google searches tell me that the error is that a function is used without being declared. however i dont know if memcpy is a function? or is the function within class memcpy (dont know if c has classes just closest equivalent that i know of) how do i debug this code and declare what needs to be declared (more importantly, if this is a stock kernel thats used by thousands of devices, how can it possibly have an undeclared function?
/edit

Answer 1

found the answer! needed

#import linux/modules.h
#import linux/kernel.h