Fatal error "asm/types.h: No such file or directory" when compiling with riscv64-unknown-elf-gcc

[0ena]

Hi,

I am trying to build a simple Linux Kernel Module that will use the printk() in order to print from inside the kernel.
At the moment I am trying to compile this example.
The make file I am using is the following:

WARN    := -W -Wall -Wstrict-prototypes -Wmissing-prototypes
INCLUDE := -isystem /lib/modules/`uname -r`/build/include
CFLAGS  := -O2 -DMODULE -D__KERNEL__ ${WARN} ${INCLUDE}
CC      := riscv64-unknown-elf-gcc
OBJS    := ${patsubst %.c, %.o, ${wildcard *.c}}

all: ${OBJS}

.PHONY: clean

clean:
        rm -rf *.o

As you can see the gcc I am using is the riscv64-unknown-elf-gcc, after building the Ariane SDK tools.
When I am executing make all, I get the following error:

riscv64-unknown-elf-gcc  -O2 -DMODULE -D__KERNEL__ -W -Wall -Wstrict-prototypes -Wmissing-prototypes -isystem /lib/modules/`uname -r`/build/include   -c -o hello-2.o hello-2.c
hello-2.c:10: warning: "MODULE" redefined
 #define MODULE
 
<command-line>: note: this is the location of the previous definition
hello-2.c:12: warning: "__KERNEL__" redefined
 #define __KERNEL__
 
<command-line>: note: this is the location of the previous definition
In file included from /usr/src/kernels/3.10.0-1127.19.1.el7.x86_64/include/linux/types.h:5,
                 from /usr/src/kernels/3.10.0-1127.19.1.el7.x86_64/include/linux/list.h:4,
                 from /usr/src/kernels/3.10.0-1127.19.1.el7.x86_64/include/linux/module.h:9,
                 from hello-2.c:14:
/usr/src/kernels/3.10.0-1127.19.1.el7.x86_64/include/uapi/linux/types.h:4:10: fatal error: asm/types.h: No such file or directory
 #include <asm/types.h>
          ^~~~~~~~~~~~~
compilation terminated.
make: *** [hello-2.o] Error 1

I am using Centos 7 and the Linux kernel is Linux 3.10.0-1127.19.1.el7.x86_64.

How can I solve this error?
I believe it might have to do with the Linux header files, but I don't know how to proceed.

Any response would be really helpful. Thank you in advance for your responses.

Kind regards,
Nassos

[Moschn]

I am no expert in kernel modules, but I think you need to link to the kernel where you want to install your module, i.e., the kernel tree in this repo. Now you are probably using your host kernel header files:

INCLUDE := -isystem /lib/modules/`uname -r`/build/include

[0ena]

Good catch @Moschn!
I'll change the makefile and link to the kernel tree of Ariane-sdk.
I'll post back if I find any difficulties.

[0ena]

Hi @Moschn,

I think I managed to compile my kernel module. What I did was the following:

• I changed my kernel module code to the following

#include <linux/module.h>   // Needed by all modules
#include <linux/kernel.h>   

static int init_module(void)
{
   printk("Hello, world 2\n");
   return 0;
}

static void cleanup_module(void)
{
   printk("Goodbye, world 2\n");
}

• I changed my Makefile to the following

WARN    := -W -Wall -Wstrict-prototypes -Wmissing-prototypes
INCLUDE := -isystem /PATH_TO_ARIANE_TOOLCHAIN/ariane-riscv-toolchain/sysroot/usr/include/
CFLAGS  := -O2 -DMODULE -D__KERNEL__ ${WARN} ${INCLUDE}
CC      := riscv64-unknown-elf-gcc
OBJS    := ${patsubst %.c, %.o, ${wildcard *.c}}

all: ${OBJS}

.PHONY: clean

clean:
        rm -rf *.o

The /ariane-riscv-toolchain/sysroot/usr/include/ has inside all the header files

aio.h        bits        envz.h         fstab.h         iconv.h     linux       net        netrose         pty.h      search.h       stdio_ext.h  termio.h     utime.h
aliases.h    byteswap.h  err.h          fts.h           ieee754.h   locale.h    netash     nfs             pwd.h      semaphore.h    stdio.h      termios.h    utmp.h
alloca.h     complex.h   errno.h        ftw.h           ifaddrs.h   malloc.h    netatalk   nl_types.h      rdma       setjmp.h       stdlib.h     tgmath.h     utmpx.h
a.out.h      cpio.h      error.h        _G_config.h     inttypes.h  math.h      netax25    nss.h           re_comp.h  sgtty.h        string.h     thread_db.h  values.h
argp.h       crypt.h     execinfo.h     gconv.h         langinfo.h  mcheck.h    netdb.h    obstack.h       regex.h    shadow.h       strings.h    time.h       video
argz.h       ctype.h     fcntl.h        getopt.h        lastlog.h   memory.h    neteconet  paths.h         regexp.h   signal.h       stropts.h    ttyent.h     wait.h
ar.h         dirent.h    features.h     glob.h          libgen.h    misc        netinet    poll.h          resolv.h   sound          sys          uchar.h      wchar.h
arpa         dlfcn.h     fenv.h         gnu             libintl.h   mntent.h    netipx     printf.h        rpc        spawn.h        syscall.h    ucontext.h   wctype.h
asm          drm         fmtmsg.h       gnu-versions.h  libio.h     monetary.h  netiucv    proc_service.h  rpcsvc     stab.h         sysexits.h   ulimit.h     wordexp.h
asm-generic  elf.h       fnmatch.h      grp.h           limits.h    mqueue.h    netpacket  protocols       sched.h    stdc-predef.h  syslog.h     unistd.h     xen
assert.h     endian.h    fpu_control.h  gshadow.h       link.h      mtd         netrom     pthread.h       scsi       stdint.h       tar.h        ustat.h

• The compilation with the makefile gave me the following warnings

riscv64-unknown-elf-gcc  -O2 -DMODULE -D__KERNEL__ -W -Wall -Wstrict-prototypes -Wmissing-prototypes -isystem /eda/tools/riscv/ariane-riscv-toolchain/sysroot/usr/include/   -c -o hello-2.o hello-2.c
hello-2.c: In function 'init_module':
hello-2.c:23:4: warning: implicit declaration of function 'printk' [-Wimplicit-function-declaration]
    printk("Hello, world 2\n");
    ^~~~~~
At top level:
hello-2.c:29:13: warning: 'cleanup_module' defined but not used [-Wunused-function]
 static void cleanup_module(void)
             ^~~~~~~~~~~~~~
hello-2.c:20:12: warning: 'init_module' defined but not used [-Wunused-function]
 static int init_module(void)
            ^~~~~~~~~~~

but created the .o file. The "implicit declaration" of "printk()" is a little bit disturbing but in at least one other thread that I found, a user with a similar problem with the "printk()" had his module working without a problem. So I decided to go ahead and test it.

• I compiled again the Linux image with my kernel module inside.

• Now when I login inside the Linux kernel, I can see my kernel module under /, but now the problem is that the image is missing the insmod and rmmod applications, so I am not able to un/load the LKM. Is there a way that I can include them inside my Linux image, in order to test my kernel module?

• One more thing is that I haven't still enabled the loadable kernel module support, would that solve my problem and include the insmod and rmmod applications or are these 2 separate issues?

Thank you in advance for your response and time.

Kind regards,
Nassos

[0ena]

I managed to load the insmod and rmmod the way I explained in #43.
Now inside my Linux kernel image, I execute insmod hello-2.o and I get the following:

[13037.464810] (missing .modinfo section): No module found in object
[13037.464810] (missing .modinfo section): No module found in object
insmod: can't insert 'hello-2.o': invalid module format

My Makefile as stated above is the following:

WARN    := -W -Wall -Wstrict-prototypes -Wmissing-prototypes
INCLUDE := -isystem /PATH_TO_ARIANE_TOOLCHAIN/ariane-riscv-toolchain/sysroot/usr/include/
CFLAGS  := -O2 -DMODULE -D__KERNEL__ ${WARN} ${INCLUDE}
CC      := riscv64-unknown-elf-gcc
OBJS    := ${patsubst %.c, %.o, ${wildcard *.c}}

all: ${OBJS}

.PHONY: clean

clean:
        rm -rf *.o

/PATH_TO_ARIANE_TOOLCHAIN/ariane-riscv-toolchain/sysroot/usr/include/ is where I have installed the ariane-sdk tools and the folder contains all the header files .h.
When I compile I don't get a .ko but a .o file.

Any ideas on what I might be doing wrong?
Is this the proper way to link my LKM to the Linux kernel for Ariane?

Thank you for the support.

Kind regards,
Nassos

[Moschn]

I think you have to compile a kernel module differently. I know this kernel module works and is crosscompiled for a Linux kernel image. Maybe take a look at their makefile

[0ena]

Hi @Moschn,

in the link you provided me, they are compiling against the Linux kernel source tree (that's why they have the LINUXSRC := $(PWD)/../linux command in their Makefile). Or at least that is what I am understanding.

To be honest I don't see any kernel source tree inside the Ariane SDK. Where is your kernel tree in this repo?
Is it the downloaded ariane-sdk folder or one of the build/buildroot folders inside it?

My current Makefile is the following (I tried to adjust it to the linked example):

DRIVER = hello-2.ko
PWD := $(shell pwd)
LINUXSRC := $(PWD)/../../../../home/user1/tools/ariane-sdk/ariane-sdk/

default:
        $(MAKE) -C $(LINUXSRC) ARCH=riscv CROSS_COMPILE=riscv64-unknown-linux-gnu- M=$(PWD)

clean:
        rm -rvf *.o *.ko

home/user1/tools/ariane-sdk/ariane-sdk/ is the path where I downloaded your repository.

Thank you for your time.

Kind regards,
Nassos

[Moschn]

The linux tree is downloaded by buildroot during build. LINUXSRC probably has to point at the root of the linux tree

[Moschn]

The linux tree is in buildroot/output/build/linux-5.1

[0ena]

I was able to solve my issue and produce a working .ko through this informative guide on how to cross-compile an LKM: https://www.kernel.org/doc/Documentation/kbuild/modules.txt

Thank you for your help @Moschn!

I am closing this thread.

[usulkies]

apk add linux-headers solved it to me on alpine

[mirabilos]

Huh, how did you?

$ make -C ~/stuff/openwrt/build_dir/toolchain-*/linux M=$PWD

I still get:

./include/uapi/linux/types.h:5:10: fatal error: asm/types.h: No such file or directory
    5 | #include <asm/types.h>
      |          ^~~~~~~~~~~~~

And no, installing the host system’s kernel headers won’t help here…

[0ena]

@mirabilos

my default in the Makefile is the following:

default: make -C $(KDIR) ARCH=riscv CROSS_COMPILE=riscv64-unknown-linux-gnu- M=$(PWD)

[mirabilos]

Athanasios Moschos dixit:

make -C $(KDIR) ARCH=riscv CROSS_COMPILE=riscv64-unknown-linux-gnu- M=$(PWD)

Ah, thanks. This was missing from all the documents, but I found similar indication, but several more variables passed, probably cargo-culted, in OpenWrt-near documentation. bye, //mirabilos -- When he found out that the m68k port was in a pretty bad shape, he did not, like many before him, shrug and move on; instead, he took it upon himself to start compiling things, just so he could compile his shell. How's that for dedication. -- Wouter, about my Debian/m68k revival