Issue while building memguard module for arm based processors

[moshah]

Hi,

I am trying to test the memguard module for arm based board like Raspberry Pi 3 board and i.MX6QP board, but while compiling the module I get an error file "asm/idle.h" not found. I searched it in the respective directory, I found that it was not there, What procedure or what changes I must make in memguard.c file so that I can get a kernel module for arm based processors.

Kernel Version I am using is 4.4.35
Its really very important for me, kindly help me out regarding this issue.

Thanks in advance.

[systempanda200]

asm/idle.h is likely a header in Linux source code.
You may like to check if the kernel you are using has been installed successfully and the kernel headers includes this file.

[moshah]

Hi,
I have installed the kernel successfully but it is not present in arch/arm/include/asm/ directory it is present in arch/x86/include/asm/ directory, I think it is architecture based file.

[moshah]

Hi,
The error I am getting is like this:
make -C /lib/modules/4.4.35-rt43/build M=/home/root/memguard-release modules
make[1]: Entering directory '/usr/src/kernel'
make[1]: Warning: File 'scripts/Makefile.extrawarn' has modification time 6455574 s in the future
make[2]: Warning: File 'scripts/Makefile.lib' has modification time 6455573 s in the future
CC [M] /home/root/memguard-release/memguard.o
/home/root/memguard-release/memguard.c:210:22: error: expected '=', ',', ';', 'asm' or 'attribute' before 'memguard_cpu_callback'
static int __cpuinit memguard_cpu_callback(struct notifier_block *nfb,
^
/home/root/memguard-release/memguard.c:228:44: error: expected '=', ',', ';', 'asm' or 'attribute' before 'memguard_cpu_notifier'
static struct notifier_block __cpuinitdata memguard_cpu_notifier =
^
/home/root/memguard-release/memguard.c: In function 'memguard_control_show':
/home/root/memguard-release/memguard.c:961:7: warning: unused variable 'buf' [-Wunused-variable]
char buf[64];
^
In file included from ./arch/arm/include/asm/cpu.h:14:0,
from ./arch/arm/include/asm/smp_plat.h:11,
from ./arch/arm/include/asm/irq_work.h:4,
from include/linux/irq_work.h:46,
from /home/root/memguard-release/memguard.c:28:
/home/root/memguard-release/memguard.c: In function 'init_module':
/home/root/memguard-release/memguard.c:1468:28: error: 'memguard_cpu_notifier' undeclared (first use in this function)
register_hotcpu_notifier(&memguard_cpu_notifier);
^
include/linux/cpu.h:258:48: note: in definition of macro 'register_hotcpu_notifier'
#define register_hotcpu_notifier(nb) ({ (void)(nb); 0; })
^
/home/root/memguard-release/memguard.c:1468:28: note: each undeclared identifier is reported only once for each function it appears in
register_hotcpu_notifier(&memguard_cpu_notifier);
^
include/linux/cpu.h:258:48: note: in definition of macro 'register_hotcpu_notifier'
#define register_hotcpu_notifier(nb) ({ (void)(nb); 0; })
^
/home/root/memguard-release/memguard.c: In function 'cleanup_module':
/home/root/memguard-release/memguard.c:1529:30: error: 'memguard_cpu_notifier' undeclared (first use in this function)
unregister_hotcpu_notifier(&memguard_cpu_notifier);
^
include/linux/cpu.h:260:50: note: in definition of macro 'unregister_hotcpu_notifier'
#define unregister_hotcpu_notifier(nb) ({ (void)(nb); })
^
/home/root/memguard-release/memguard.c: At top level:
/home/root/memguard-release/memguard.c:1381:30: warning: 'memguard_idle_nb' defined but not used [-Wunused-variable]
static struct notifier_block memguard_idle_nb = {
^
scripts/Makefile.build:264: recipe for target '/home/root/memguard-release/memguard.o' failed
make[2]: *** [/home/root/memguard-release/memguard.o] Error 1
Makefile:1405: recipe for target 'module/home/root/memguard-release' failed
make[1]: *** [module/home/root/memguard-release] Error 2
make[1]: Leaving directory '/usr/src/kernel'
Makefile:9: recipe for target 'all' failed
make: *** [all] Error 2

Please help me out regarding this.
Thank in advance.

[heechul]

I pushed a small change (removing __cpuinit and __cpuinitdata), which should fix the compilation problem.

[moshah]

Respected Mr. Heechul Yun,

The compilation of the module was successful, but it shows warning as follows:

make -C /lib/modules/4.4.35-rt43/build M=/home/root/memguard-release modules
make[1]: Entering directory '/usr/src/kernel'
make[1]: Warning: File 'scripts/Makefile.extrawarn' has modification time 6455816 s in the future
make[2]: Warning: File 'scripts/Makefile.lib' has modification time 6455816 s in the future
CC [M] /home/root/memguard-release/memguard.o
make[2]: warning: Clock skew detected. Your build may be incomplete.
Building modules, stage 2.
make[2]: Warning: File 'scripts/Makefile.lib' has modification time 6455813 s in the future
MODPOST 1 modules

WARNING: "idle_notifier_unregister" [/home/root/memguard-release/memguard.ko] undefined!
WARNING: "idle_notifier_register" [/home/root/memguard-release/memguard.ko] undefined!

CC /home/root/memguard-release/memguard.mod.o
LD [M] /home/root/memguard-release/memguard.ko
make[2]: warning: Clock skew detected. Your build may be incomplete.
make[1]: warning: Clock skew detected. Your build may be incomplete.
make[1]: Leaving directory '/usr/src/kernel'

When I tried to load the module it shows
root@raspberrypi3:~/memguard-release# insmod memguard.ko
insmod: ERROR: could not insert module memguard.ko: Unknown symbol in module

dmeg shows:
[ 703.782738] memguard: Unknown symbol idle_notifier_register (err 0)
[ 703.783098] memguard: Unknown symbol idle_notifier_unregister (err 0)

Kindly help me out regarding this issue, Thanks a lot in advance.