Kernel driver with 2 files

zvivered · 03-21-2020, 03:10 PM

Hello,

Attached Makefile and source code for a simple kernel device driver.
With this Makefile, if there a syntax error in file1.c, it's ignored.

file1.o, file2.o, file1.ko are created but it's a fake.

The nm output of file1.o is identical to that of file2.o

Can you please help understand what is wrong in my Makefile ?

Thank you,
Zvika

TB0ne · 03-21-2020, 04:35 PM

Quote:

Originally Posted by zvivered

Hello,
Attached Makefile and source code for a simple kernel device driver. With this Makefile, if there a syntax error in file1.c, it's ignored.

file1.o, file2.o, file1.ko are created but it's a fake.

The nm output of file1.o is identical to that of file2.o Can you please help understand what is wrong in my Makefile ?

Thank you,
Zvika

So you would like us to debug your code for you??? Have you read the docs on the makefiles for kernel modules?
https://www.kernel.org/doc/Documenta...ld/modules.txt

You've been working on kernel modules for at least three years now..your entire makefile (as posted) consists of 7 lines, all of which are pretty straight-forward. Why do you think, if there's an error in the file1.c code and you ignore it, that you're going to get valid output?

zvivered · 03-22-2020, 01:47 AM

Hello TBOne,

I read the link you sent.
Did not find error in my Makefile.

If there is an error in file1.c, build should fail.
But upon build completion I got ko.
It does not make sense.

Accoding to nm, the ko contains symbols from file2 only.

Thank you,
Zvika

zvivered · 03-22-2020, 08:47 AM

Hello,

The right Makefile is:
...
obj-m += mydrv.o
mydrv-y += file1.o
mydrv-y += file2.o
...

The output is mydrv.ko

Thank you,
Zvika

TB0ne · 03-22-2020, 10:08 AM

Quote:

Originally Posted by zvivered

Hello TBOne,
I read the link you sent. Did not find error in my Makefile.

If there is an error in file1.c, build should fail. But upon build completion I got ko. It does not make sense. Accoding to nm, the ko contains symbols from file2 only.

And since you didn't tell us what this supposed 'syntax error' was/is in your first post (or here), how are we to know what it's doing or why?

Quote:

Originally Posted by zvivered

The right Makefile is:
...
obj-m += mydrv.o
mydrv-y += file1.o
mydrv-y += file2.o
...

The output is mydrv.ko

Glad you read the documentation.