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.