how to add a simple kernel module with customized kernel

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1

hai all,

i followed this link to compile a kernel for bbb
http://eewiki.net/display/linuxonarm/BeagleBone+Black#BeagleBoneBlack-BasicRequirements

i try to mount my kernel using sd card, after a series of bugs finally i can able to boot my kernel using the precompiled ubuntu rootfs which was given in the above link.
but when i tried to add a hello world module into my bbb . i got the following error
i googled it all the possible ways but none of them helped me .

ubuntu@arm:/opt$ sudo insmod hello.ko
Error: could not insert module hello.ko: Invalid module format

ubuntu@arm:/opt$

when i execute modinfo command from the bbb. i got the following log information

ubuntu@arm:/opt$ modinfo hello.ko

filename: /opt/hello.ko
description: A Simple Hello World module
author: sivakumar
license: GPL
srcversion: F545620F75762B1AAE668ED
depends:
vermagic: 3.8.13 SMP mod_unload modversions ARMv7 p2v8

help me how to insert the module into my beagelobne black kernel.

regards
siva

2

What kind of kernel did you build? My stock kernel is “Thumb2” so modinfo shows:

vermagic: 3.8.13-bone41 SMP mod_unload modversions ARMv7 thumb2 p2v8

If your kernel is Thumb2, then your module needs to be Thumb2, also.

mark@p3d:/lib/modules/3.8.13-bone41/kernel/drivers% zcat /proc/config.gz | grep -i thumb
CONFIG_ARM_THUMB=y
CONFIG_ARM_THUMBEE=y
CONFIG_THUMB2_KERNEL=y
CONFIG_THUMB2_AVOID_R_ARM_THM_JUMP11=y
CONFIG_XZ_DEC_ARMTHUMB=y

Mark

3

hai,
i used the kernel

ubuntu@arm:/proc$ uname -ar
Linux arm 3.12.13-bone12 #1 SMP Thu Mar 20 04:17:43 IST 2014 armv7l armv7l armv7l GNU/Linux

ubuntu@arm:/proc$ zcat /proc/config.gz | grep -i thumb

CONFIG_ARM_THUMB=y
CONFIG_ARM_THUMBEE=y
# CONFIG_THUMB2_KERNEL is not set
CONFIG_XZ_DEC_ARMTHUMB=y
ubuntu@arm:/proc$

is Thumb2 option to be enabled or not necessary …
regards
siva

4

i noticed one more difference (mistake) from my side

ubuntu@arm:/opt$ modinfo -F vermagic hello.ko
3.8.13 SMP mod_unload modversions ARMv7 p2v8

ubuntu@arm:/opt$ uname -r
3.12.13-bone12
ubuntu@arm:/opt$

i compiled the module against the 3.8.13 kernel !! might be this cause the issue. .i will try to resolve the issue