Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  1) // SPDX-License-Identifier: GPL-2.0-only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  2) #include <linux/module.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  3) #include <linux/kthread.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  4) #include <linux/ftrace.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  5) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  6) extern void my_direct_func1(void);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  7) extern void my_direct_func2(void);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  8) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  9) void my_direct_func1(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) 	trace_printk("my direct func1\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) void my_direct_func2(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) 	trace_printk("my direct func2\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) extern void my_tramp1(void *);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) extern void my_tramp2(void *);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) static unsigned long my_ip = (unsigned long)schedule;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) asm (
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) "	.pushsection    .text, \"ax\", @progbits\n"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) "	.type		my_tramp1, @function\n"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) "	.globl		my_tramp1\n"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) "   my_tramp1:"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) "	pushq %rbp\n"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) "	movq %rsp, %rbp\n"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) "	call my_direct_func1\n"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) "	leave\n"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) "	.size		my_tramp1, .-my_tramp1\n"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) "	ret\n"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) "	.type		my_tramp2, @function\n"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) "	.globl		my_tramp2\n"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) "   my_tramp2:"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) "	pushq %rbp\n"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) "	movq %rsp, %rbp\n"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) "	call my_direct_func2\n"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) "	leave\n"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) "	ret\n"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) "	.size		my_tramp2, .-my_tramp2\n"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) "	.popsection\n"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) );
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) static unsigned long my_tramp = (unsigned long)my_tramp1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) static unsigned long tramps[2] = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) 	(unsigned long)my_tramp1,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) 	(unsigned long)my_tramp2,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) static int simple_thread(void *arg)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) 	static int t;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) 	int ret = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) 	while (!kthread_should_stop()) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) 		set_current_state(TASK_INTERRUPTIBLE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) 		schedule_timeout(2 * HZ);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) 		if (ret)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) 			continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) 		t ^= 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) 		ret = modify_ftrace_direct(my_ip, my_tramp, tramps[t]);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) 		if (!ret)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) 			my_tramp = tramps[t];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) 		WARN_ON_ONCE(ret);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) static struct task_struct *simple_tsk;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) static int __init ftrace_direct_init(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) 	int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) 	ret = register_ftrace_direct(my_ip, my_tramp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) 	if (!ret)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) 		simple_tsk = kthread_run(simple_thread, NULL, "event-sample-fn");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) 	return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) static void __exit ftrace_direct_exit(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) 	kthread_stop(simple_tsk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) 	unregister_ftrace_direct(my_ip, my_tramp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) module_init(ftrace_direct_init);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) module_exit(ftrace_direct_exit);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) MODULE_AUTHOR("Steven Rostedt");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) MODULE_DESCRIPTION("Example use case of using modify_ftrace_direct()");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) MODULE_LICENSE("GPL");