1 // SPDX-License-Identifier: GPL-2.0-only 2 #include <linux/module.h> 3 4 #include <linux/mm.h> /* for handle_mm_fault() */ 5 #include <linux/ftrace.h> 6 #include <linux/sched/stat.h> 7 8 extern void my_direct_func(unsigned long ip); 9 10 void my_direct_func(unsigned long ip) 11 { 12 trace_printk("ip %lx\n", ip); 13 } 14 15 extern void my_tramp(void *); 16 17 asm ( 18 " .pushsection .text, \"ax\", @progbits\n" 19 " .type my_tramp, @function\n" 20 " .globl my_tramp\n" 21 " my_tramp:" 22 " pushq %rbp\n" 23 " movq %rsp, %rbp\n" 24 " pushq %rdi\n" 25 " movq 8(%rbp), %rdi\n" 26 " call my_direct_func\n" 27 " popq %rdi\n" 28 " leave\n" 29 " ret\n" 30 " .size my_tramp, .-my_tramp\n" 31 " .popsection\n" 32 ); 33 34 static struct ftrace_ops direct; 35 36 static int __init ftrace_direct_multi_init(void) 37 { 38 ftrace_set_filter_ip(&direct, (unsigned long) wake_up_process, 0, 0); 39 ftrace_set_filter_ip(&direct, (unsigned long) schedule, 0, 0); 40 41 return register_ftrace_direct_multi(&direct, (unsigned long) my_tramp); 42 } 43 44 static void __exit ftrace_direct_multi_exit(void) 45 { 46 unregister_ftrace_direct_multi(&direct, (unsigned long) my_tramp); 47 } 48 49 module_init(ftrace_direct_multi_init); 50 module_exit(ftrace_direct_multi_exit); 51 52 MODULE_AUTHOR("Jiri Olsa"); 53 MODULE_DESCRIPTION("Example use case of using register_ftrace_direct_multi()"); 54 MODULE_LICENSE("GPL"); 55