Get started with ‘Linux Device Drivers’

If you’re reading the book ‘Linux Device Drivers’, you probably will meet the same problem.

First, you will see this error,

error: linux/module.h: No such file or directory

I f you use your gcc with -v, you will find

#include “…” search starts here:
#include <…> search starts here:
 /usr/local/include
 /usr/lib/gcc/i486-linux-gnu/4.4.3/include
 /usr/lib/gcc/i486-linux-gnu/4.4.3/include-fixed
 /usr/include
End of search list.
GNU C (Ubuntu 4.4.3-4ubuntu5) version 4.4.3 (i486-linux-gnu)
    compiled by GNU C version 4.4.3, GMP version 4.3.2, MPFR version 2.4.2-p1.
GGC heuristics: —param ggc-min-expand=100 —param ggc-min-heapsize=131072
Compiler executable checksum: 5998ce5f1765e99eea5269f4c1e38d44
1.c:2:25: error: linux/module.h: No such file or directory

You will see module.h is not included within /usr/include.  Instead, it’s under /usr/src/linux-headers-2.6.32-33-generic/include/linux/.

So, how to make gcc check my path instead of default one?

Make your own Makefile:

bj-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

Then type command: make.  You will see:

$ make
make -C /lib/modules/2.6.32-33-generic/build M=/home/lixian/LinuxDeviceDrivers/ex modules
make[1]: Entering directory `/usr/src/linux-headers-2.6.32-33-generic’
  Building modules, stage 2.
  MODPOST 0 modules
make[1]: Leaving directory `/usr/src/linux-headers-2.6.32-33-generic’

Make V=1, then get

test -e include/linux/autoconf.h -a -e include/config/auto.conf || (        \
    echo;                                \
    echo “  ERROR: Kernel configuration is invalid.”;        \
    echo “         include/linux/autoconf.h or include/config/auto.conf are missing.”;    \
    echo “         Run ‘make oldconfig && make prepare’ on kernel src to fix it.”;    \
    echo;                                \
    /bin/false)

But actually, under include/linux exists autoconf.h.

Reference:

http://www.digitalhermit.com/linux/Kernel-Build-HOWTO.html

http://en.tldp.org/LDP/lkmpg/2.6/html/index.html

http://stackoverflow.com/questions/4715259/linux-modpost-does-not-build-anything

Documentation/kbuild/modules.txt

http://www.digitalhermit.com/linux/Kernel-Build-HOWTO.html

(Source: learningdevicedrivers.blogspot.com)