[SOLVED] hello world module problem

[jesusitoLinux]

Hello friends! I'm following the guide "The linux kernel module programming guide". I'm trying with the hello world mode, wich code is this:

#include <linux/module.h>
#include <linux/kernel.h>
int init_module(void)
{
  printk(KERN_INFO "Hello world 1.\n");

return 0;
}
void cleanup_module(void)
{
  printk(KERN_INFO "Goodbye world 1.\n");
}

The original make file in the guide is wrong. This is the code

obj−m += hello−1.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

Which tells "Nothing to be done for all"

So i found this makefile in the web:

obj-m += hello.o

KDIR    := /lib/modules/2.6.32-27-generic/build
PWD    := $(/home/jesus/pruebas/c/)

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

Which trhows this error message:

make -C /lib/modules/2.6.32-27-generic/build SUBDIRS= modules
make[1]: se ingresa al directorio `/usr/src/linux-headers-2.6.32-27-generic'
  CHK     include/linux/version.h
  CHK     include/linux/utsrelease.h
  SYMLINK include/asm -> include/asm-x86
make[2]: *** No hay ninguna regla para construir el objetivo `kernel/bounds.c', necesario para `kernel/bounds.s'.  Alto.
make[1]: *** [prepare0] Error 2
make[1]: se sale del directorio `/usr/src/linux-headers-2.6.32-27-generic'
make: *** [default] Error 2

Please help!!!
Many thanks!

[jesusitoLinux]

I found the error for the first Makefile. After "all:" there must be a "tab" instead of spaces:

obj-m += hello.o
all:
	make -C /lib/modules/2.6.32-27-generic/build M=/home/jesus/pruebas/c modules
clean:
	make -C /lib/modules/2.6.32-27-generic/build M=/home/jesus/pruebas/c clean

With this makefile, i get this error message:

make -C /lib/modules/2.6.32-27-generic/build M=/home/jesus/pruebas/c modules
make[1]: se ingresa al directorio `/usr/src/linux-headers-2.6.32-27-generic'
make[2]: *** No hay ninguna regla para construir el objetivo `/home/jesus/pruebas/c/hello.c', necesario para `/home/jesus/pruebas/c/hello.o'.  Alto.
make[1]: *** [_module_/home/jesus/pruebas/c] Error 2
make[1]: se sale del directorio `/usr/src/linux-headers-2.6.32-27-generic'
make: *** [all] Error 2

[heliks0700]

Good day.
I also had issue compiling hello world module.
This helped in my case.
first manually write your Makefile, dont copy and paste from tutorial.
Actually daches ,and another characters are differ.

obj-m , −C , −r

The dache signs here copied from your post and are differ than ascii dash '-' .

Second.
I don't know much about kernel policy of compiling modules, but some modules
requare Kbuild file, others dont.

So try this way.

Cut obj-m += hello.o string from your Makefile, create new Kbuild file
in the same dir and save obj-m += hello.o string in Kbuild file and then compile.

[heliks0700]

Good day.
I also had issue compiling hello world module.
This helped in my case.
first manually write your Makefile, dont copy and paste from tutorial.
Actually daches ,and another characters are differ.

obj-m , −C , −r

The dache signs here copied from your post and are differ than ascii dash '-' .

Second.
I don't know much about kernel policy of compiling modules, but some modules
requare Kbuild file, others dont.

So try this way.

Cut obj-m += hello.o string from your Makefile, create new Kbuild file
in the same dir and save obj-m += hello.o string in Kbuild file and then compile.

[jesusitoLinux]

Hi heliks!! Many thanks!! This make file i have just found, works properly too!

ifeq ($(KERNELRELEASE),)

# Assume the source tree is where the running kernel was built
# You should set KERNELDIR in the environment if it's elsewhere
KERNELDIR ?= /lib/modules/2.6.32-27-generic/build

# The current directory is passed to sub-makes as argument
PWD := /home/jesus/pruebas/module2/

modules:
	$(MAKE) -C $(KERNELDIR) M=$(PWD) modules

modules_install:
	$(MAKE) -C $(KERNELDIR) M=$(PWD) modules_install

clean:
	rm -rf *.o *~ core .depend .*.cmd *.ko *.mod.c .tmp_versions

.PHONY: modules modules_install clean

else
# called from kernel build system: just declare what our modules are
	obj-m := hello.o
	obj-m := hello2.o
endif