Simple Makefile error:: all nothing need to be done.

knockout_artist · 11-17-2007, 11:18 AM

Good Day,
Raed this code from the book trying to compile it, But make file doesn't seems to work.

Code:

#include<linux/modules.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");

}

Makefile

Code:

obj−m += hello1.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

Upon running make command:

Quote:

[root@stone-age mod]# make
uname: extra operand `−r'
Try `uname --help' for more information.
uname: extra operand `−r'
Try `uname --help' for more information.
make: Nothing to be done for `all'.
[root@stone-age mod]#

Any one? any ideas?

Thanks.

theriddle · 11-17-2007, 11:32 AM

Try

Code:

obj−m += hello1.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

or maybe

Code:

obj−m += hello1.o
all:
        make −C /lib/modules/`uname −r`/build M=$(PWD) modules
clean:
        make −C /lib/modules/`uname −r`/build M=$(PWD) clean

knockout_artist · 11-18-2007, 02:43 AM

^ didn't work.
Make acts like as It doesn't see file hello.c in directory.
Can some post a working code for hello world kernel module + make file.

Thanks.

osor · 11-18-2007, 02:24 PM

The problem here is very subtle. It’s because you copied and pasted your Makefile from a badly-created pdf. See this line:

Quote:

Originally Posted by knockout_artist

Code:

        make −C /lib/modules/$(shell `uname −r`)/build M=$(PWD) modules

is supposed to be

Code:

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

Notice that in the first the argument to uname contains the unicode MINUS SIGN (codepoint U+2212), and in the second it is the ASCII/Unicode HYPHEN-MINUS (codepoint U+002D). The same thing happened to all the hyphens in your Makefile (I see five of them). Additionally, there should be a tab instead of 8 spaces.

Moral of the story: don’t blindly copy and paste from pdf files.

osor · 11-18-2007, 02:30 PM

I’ve colored them for you:

Quote:

Originally Posted by knockout_artist

Makefile

Code:

obj−m += hello1.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

knockout_artist · 11-18-2007, 09:53 PM

hello.c

Code:

 
#include <linux/module.h>       /* Needed by all modules */
#include <linux/kernel.h>       /* Needed for KERN_INFO */
int init_module(void)
{
        printk(KERN_INFO "Hello world 1.\n");
        /*
         * A non 0 return means init_module failed; module can't be loaded.
         */
        return 0;
}
void cleanup_module(void)
{
        printk(KERN_INFO "Goodbye world 1.\n");
}

Makefile:

Code:

obj-m += hello.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

Quote:

[root@stone-age mod]# make
make: Nothing to be done for `all'.
[root@stone-age mod]#

May be I can comile it with one command line.
I remember using __WALL__ kind of command to compile modules.

Thanks.

osor · 11-18-2007, 11:03 PM

Again, the make utility uses tabs to interpret the commands for a target. Originally, you had 8 spaces. Now, you have nothing. What you need to do is change this:

Quote:

Originally Posted by knockout_artist

Makefile:

Code:

obj-m += hello.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

to this
Makefile:

Code:

obj-m += hello.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

Notice that the commands are preceded by tabstops (Ctrl+I) instead of spaces.

knockout_artist · 11-19-2007, 02:08 PM

^ OSOR brother, its working now Thank you.
How ever I am using it on RH now.
Tonite I am going to try same code on the machine where trouble started(FC6).

Thank you very much once again.

kimjoys · 06-22-2009, 12:12 PM

nevermind

sailorbob · 10-23-2009, 04:28 AM

Wow, thanks! This was driving me insane. The next thing I was going to do would be to rm the makefile and type it in by hand.