CODEWITHSUNDEEP
clinuxmakefilelinux-kernel
Honore
Honore

Reputation: 63

Linux Kernel Module Compilation

I am having trouble building helloworld Linux kernel module. I am using VirtualBox from SUN with Ubuntu ISO image that I downloaded from Ubuntu web site. Any help will be greatly appreciated. Bellow are the c code and the error message that I am getting:

The module file is called hellowrld.c and it contains the code below:

    #include <linux/module.h>    // included for all kernel modules
    #include <linux/kernel.h>    // included for KERN_INFO
    #include <linux/init.h>      // included for __init and __exit macros

    MODULE_LICENSE("GPL");

    static int __init helloworld_init(void)
    {
        printk(KERN_INFO "Hello world!\n");
        return 0;    
    }

    static void __exit helloworld_exit(void)
    {
        printk(KERN_INFO "Cleaning up module.\n");
    }

    module_init(helloworld_init);
    module_exit(helloworld_exit);

The make file is called makefile.c and it contains the code below:

    obj -m += helloworld.o

    all:
         make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules

    clean:
          make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean

The error message that I am getting when I run make command is below:

cc    makefile.c -o makefile
makefile.c:1:4: error: expected '=', ',', ';', 'asm' or '__attribute__' before '-' token 
obj-m helloworld.o

make: *** No targets specified no makefile found. Stop

Upvotes: 1

Views: 2029

Answers (1)

Knud Larsen
Knud Larsen

Reputation: 5909

The right Makefile looks like this ...

obj-m    := helloworld.o

KDIR    := /lib/modules/$(shell uname -r)/build
PWD    := $(shell pwd)

default:
    $(MAKE) -C $(KDIR) SUBDIRS=$(PWD) modules

clean:
    rm -rf *.o *.ko *.mod.* *.symvers *.order

Upvotes: 4

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