1 // SPDX-License-Identifier: GPL-2.0-only
2 #include <linux/module.h>
4 #include <linux/mm.h> /* for handle_mm_fault() */
5 #include <linux/ftrace.h>
7 extern void my_direct_func(struct vm_area_struct *vma, unsigned long address,
8 unsigned int flags, struct pt_regs *regs);
10 void my_direct_func(struct vm_area_struct *vma, unsigned long address,
11 unsigned int flags, struct pt_regs *regs)
13 trace_printk("handle mm fault vma=%p address=%lx flags=%x regs=%p\n",
14 vma, address, flags, regs);
17 extern void my_tramp(void *);
20 " .pushsection .text, \"ax\", @progbits\n"
21 " .type my_tramp, @function\n"
30 " call my_direct_func\n"
37 " .size my_tramp, .-my_tramp\n"
42 static int __init ftrace_direct_init(void)
44 return register_ftrace_direct((unsigned long)handle_mm_fault,
45 (unsigned long)my_tramp);
48 static void __exit ftrace_direct_exit(void)
50 unregister_ftrace_direct((unsigned long)handle_mm_fault,
51 (unsigned long)my_tramp);
54 module_init(ftrace_direct_init);
55 module_exit(ftrace_direct_exit);
57 MODULE_AUTHOR("Steven Rostedt");
58 MODULE_DESCRIPTION("Another example use case of using register_ftrace_direct()");
59 MODULE_LICENSE("GPL");