/* kallsyms_compat.h - Compatibility layer for kallsyms_lookup_name */

#ifndef KALLSYMS_COMPAT_H
#define KALLSYMS_COMPAT_H

#include <linux/version.h>
#include <linux/kallsyms.h>
#include <linux/kprobes.h>

/* kallsyms_lookup_name is no longer exported since kernel 5.7 */
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 7, 0)

/* Function pointer for kallsyms_lookup_name */
static unsigned long (*mcctrl_kallsyms_lookup_name)(const char *name);

/* Kprobe-based approach to get kallsyms_lookup_name function pointer */
static struct kprobe kp_kallsyms = {
	.symbol_name = "kallsyms_lookup_name"
};

static int init_kallsyms_lookup(void)
{
	int ret;
	
	ret = register_kprobe(&kp_kallsyms);
	if (ret < 0) {
		pr_err("register_kprobe failed, returned %d\n", ret);
		return ret;
	}
	
	mcctrl_kallsyms_lookup_name = (unsigned long (*)(const char *))kp_kallsyms.addr;
	unregister_kprobe(&kp_kallsyms);
	
	if (!mcctrl_kallsyms_lookup_name) {
		pr_err("Failed to get kallsyms_lookup_name address\n");
		return -EINVAL;
	}
	
	return 0;
}

static void cleanup_kallsyms_lookup(void)
{
	mcctrl_kallsyms_lookup_name = NULL;
}

static inline unsigned long mcctrl_lookup_name(const char *name)
{
	if (mcctrl_kallsyms_lookup_name)
		return mcctrl_kallsyms_lookup_name(name);
	return 0;
}

#else /* LINUX_VERSION_CODE < KERNEL_VERSION(5, 7, 0) */

static inline int init_kallsyms_lookup(void)
{
	return 0;
}

static inline void cleanup_kallsyms_lookup(void)
{
}

static inline unsigned long mcctrl_lookup_name(const char *name)
{
	return kallsyms_lookup_name(name);
}

#endif /* LINUX_VERSION_CODE >= KERNEL_VERSION(5, 7, 0) */

#endif /* KALLSYMS_COMPAT_H */