hello.c

#include <linux/module.h>    // included for all kernel modules
#include <linux/kernel.h>    // included for KERN_INFO
#include <linux/init.h>      // included for __init and __exit macros

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Lakshmanan");
MODULE_DESCRIPTION("A Simple Hello World module");

#define ACTLR_EL1_EnTSO   (1ULL << 1)

static void pokeit(void* turnOn) {
	u64 actlr = read_sysreg(actlr_el1);
	if (turnOn) {
		actlr |= ACTLR_EL1_EnTSO;
	} else {
		actlr &= ~ACTLR_EL1_EnTSO;
	}
	write_sysreg(actlr, actlr_el1);
}

static int __init hello_init(void)
{
    printk(KERN_INFO "Hello world!\n");
    on_each_cpu(pokeit, "yes", true);
    return 0;    // Non-zero return means that the module couldn't be loaded.
}

static void __exit hello_cleanup(void)
{
    on_each_cpu(pokeit, NULL, true);
    printk(KERN_INFO "Cleaning up module.\n");
}

module_init(hello_init);
module_exit(hello_cleanup);