Compiling module for wireless card

[Tony3]

I am after compiling a module for a wireless card. I got plenty of errors, thus decided to go to the basis and test the creation of a "hello" module.

I am using the image: Armbian_22.11.4_Orangepi5_jammy_legacy_5.10.110_xfce_desktop.img

 

vi hello.c

-------------------------------------------------

#include <linux/init.h>
#include <linux/module.h>
static int hello_init(void)
{
printk("Hello Orange Pi -- init\n");
return 0;
}
static void hello_exit(void)
{
printk("Hello Orange Pi -- exit\n");
return;
}
module_init(hello_init);
module_exit(hello_exit);
MODULE_LICENSE("GPL");

------------------------------------------

orangepi@orangepi:~$ vim Makefile
ifneq ($(KERNELRELEASE),)
obj-m:=hello.o
else
KDIR :=/lib/modules/$(shell uname -r)/build
PWD :=$(shell pwd)
all:
    make -C $(KDIR) M=$(PWD) modules
clean:
    rm -f *.ko *.o *.mod.o *.mod *.symvers *.cmd *.mod.c *.order
endif

------------------------------------------------

 

Then try to compile the module :

 make -C /lib/modules/$(uname -r)/build M=$(pwd) modules

 

Running that command the first time after a fresh install of the jammy image, I realised that the directory /usr/src/linux-headers-5.10.110-rockchip-rk3588//scripts/mod

was missing the modpost program.

So I created it with the command:  sudo make M=scripts/mod

 

Then I run again 

make -C /lib/modules/$(uname -r)/build M=$(pwd) modules and got the log

--------------------------------
make: Entering directory '/usr/src/linux-headers-5.10.110-rockchip-rk3588'
arch/arm64/Makefile:44: Detected assembler with broken .inst; disassembly will be unreliable
  CC [M]  /home/eric/installed/TestCompileModule/hello.o
  MODPOST /home/eric/installed/TestCompileModule/Module.symvers
ERROR: modpost: "_mcount" [/home/eric/installed/TestCompileModule/hello.ko] undefined!
make[1]: *** [scripts/Makefile.modpost:169: /home/eric/installed/TestCompileModule/Module.symvers] Error 1
make[1]: *** Deleting file '/home/eric/installed/TestCompileModule/Module.symvers'
make: *** [Makefile:1822: modules] Error 2
make: Leaving directory '/usr/src/linux-headers-5.10.110-rockchip-rk3588'

------------------------------------ 

 

There are few errors in it:

  - "assembler with broken .inst; disassembly will be unreliable", is this important?

  - "ERROR: modpost: "_mcount"", This seems blocking as there is no .ko generated

 

Any idea about what I am missing?

 

Thank you.

 

[OttawaHacker]

9 hours ago, Tony3 said:

I am after compiling a module for a wireless card. I got plenty of errors, thus decided to go to the basis and test the creation of a "hello" module.

I think you are going the complex route. The armbian build system is incredible, all you need is setup a VM with ubuntu and the build system will generate a custom image with your kernel customizations. Please submit a PR if you can validate the build and hardware - this distribution needs more modules. I recently submitted a PR that got accepted for MediaTek USB devices. 

[royk]

You actually don't need to create a virtual machine, you could also do it within Armbian, the rk3588 is fast enough with enough cooling

[Tony3]

Actually I managed to build my wireless module by only using the linx header files.

It did not work initially, because I had forgotten to run "make scripts" in the "linux header" directory, after running that, my "_mcount" error disappeared.

Thanks for your advices.

[gounthar]

I have the same kind of problem, trying to build a rtl8821CU module for the Rock5B.
I have installed the whole firmware package through

armbian-config

.

Then:

sudo apt update
sudo apt upgrade
sudo apt install build-essential dkms
sudo apt install git
git clone https://github.com/whitebatman2/rtl8821CU.git
cd rtl8821CU
sudo make
make ARCH=aarch64 CROSS_COMPILE= -C /lib/modules/6.2.0-rc1-station-m6/build M=/home/poddingue/rtl8821CU  modules
make[1]: Entering directory '/usr/lib/modules/6.2.0-rc1-station-m6/build'
make[1]: *** No rule to make target 'modules'.  Stop.
make[1]: Leaving directory '/usr/lib/modules/6.2.0-rc1-station-m6/build'
make: *** [Makefile:1923: modules] Error 2

but it fails...
`uname -r` gives me `6.2.0-rc1-station-m6`.
 

ll /lib/modules/6.2.0-rc1-station-m6/
total 1392
drwxr-xr-x 11 root root   4096 Mar 20 15:19 kernel
-rw-r--r--  1 root root 320711 Mar 17 14:22 modules.alias
-rw-r--r--  1 root root 327286 Mar 17 14:22 modules.alias.bin
-rw-r--r--  1 root root  16981 Mar 17 14:22 modules.builtin
-rw-r--r--  1 root root  37042 Mar 17 14:22 modules.builtin.alias.bin
-rw-r--r--  1 root root  18873 Mar 17 14:22 modules.builtin.bin
-rw-r--r--  1 root root 117401 Mar 17 14:22 modules.builtin.modinfo
-rw-r--r--  1 root root  79754 Mar 17 14:22 modules.dep
-rw-r--r--  1 root root 123183 Mar 17 14:22 modules.dep.bin
-rw-r--r--  1 root root    243 Mar 17 14:22 modules.devname
-rw-r--r--  1 root root  38207 Mar 17 14:22 modules.order
-rw-r--r--  1 root root    703 Mar 17 14:22 modules.softdep
-rw-r--r--  1 root root 136364 Mar 17 14:22 modules.symbols
-rw-r--r--  1 root root 170537 Mar 17 14:22 modules.symbols.bin

 

[balbes150]

11 часов назад, gounthar сказал:

I have the same kind of problem, trying to build a rtl8821CU module for the Rock5B.

 

You are using an old version of the kernel. Use the latest version of the images, there is already the necessary module there.

 

https://github.com/150balbes/build/blob/ed6c18895b1ed1429ea1a22210a826039d177d58/config/kernel/linux-station-m3-current.config#L2939

[gounthar]

Thank you @balbes150.
I guess there is no other alternative to the existing image?
I have to rewrite everything with the new image, I can't update the board with the latest kernel because it's not official yet.?

[balbes150]

2 часа назад, gounthar сказал:

I guess there is no other alternative to the existing image?

 

Clone my GIT and build the kernel (you can additionally change the configuration as you wish) - get a DEB package for manual installation\updating of the kernel on any system. The assembly can be done on the rock 5b itself, the assembly time is small.

[gounthar]

Good to know, thank you, I'll try that.