L8NIT3TR0UBL3 L8NIT3TR0UBL3 - 1 year ago 80
Android Question

android kernel build (first time)

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


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?


Answer Source

found the answer! needed

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