1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-only
2*4882a593Smuzhiyun #include <linux/module.h>
3*4882a593Smuzhiyun
4*4882a593Smuzhiyun #include <linux/mm.h> /* for handle_mm_fault() */
5*4882a593Smuzhiyun #include <linux/ftrace.h>
6*4882a593Smuzhiyun
7*4882a593Smuzhiyun extern void my_direct_func(struct vm_area_struct *vma,
8*4882a593Smuzhiyun unsigned long address, unsigned int flags);
9*4882a593Smuzhiyun
my_direct_func(struct vm_area_struct * vma,unsigned long address,unsigned int flags)10*4882a593Smuzhiyun void my_direct_func(struct vm_area_struct *vma,
11*4882a593Smuzhiyun unsigned long address, unsigned int flags)
12*4882a593Smuzhiyun {
13*4882a593Smuzhiyun trace_printk("handle mm fault vma=%p address=%lx flags=%x\n",
14*4882a593Smuzhiyun vma, address, flags);
15*4882a593Smuzhiyun }
16*4882a593Smuzhiyun
17*4882a593Smuzhiyun extern void my_tramp(void *);
18*4882a593Smuzhiyun
19*4882a593Smuzhiyun asm (
20*4882a593Smuzhiyun " .pushsection .text, \"ax\", @progbits\n"
21*4882a593Smuzhiyun " .type my_tramp, @function\n"
22*4882a593Smuzhiyun " .globl my_tramp\n"
23*4882a593Smuzhiyun " my_tramp:"
24*4882a593Smuzhiyun " pushq %rbp\n"
25*4882a593Smuzhiyun " movq %rsp, %rbp\n"
26*4882a593Smuzhiyun " pushq %rdi\n"
27*4882a593Smuzhiyun " pushq %rsi\n"
28*4882a593Smuzhiyun " pushq %rdx\n"
29*4882a593Smuzhiyun " call my_direct_func\n"
30*4882a593Smuzhiyun " popq %rdx\n"
31*4882a593Smuzhiyun " popq %rsi\n"
32*4882a593Smuzhiyun " popq %rdi\n"
33*4882a593Smuzhiyun " leave\n"
34*4882a593Smuzhiyun ASM_RET
35*4882a593Smuzhiyun " .size my_tramp, .-my_tramp\n"
36*4882a593Smuzhiyun " .popsection\n"
37*4882a593Smuzhiyun );
38*4882a593Smuzhiyun
39*4882a593Smuzhiyun
ftrace_direct_init(void)40*4882a593Smuzhiyun static int __init ftrace_direct_init(void)
41*4882a593Smuzhiyun {
42*4882a593Smuzhiyun return register_ftrace_direct((unsigned long)handle_mm_fault,
43*4882a593Smuzhiyun (unsigned long)my_tramp);
44*4882a593Smuzhiyun }
45*4882a593Smuzhiyun
ftrace_direct_exit(void)46*4882a593Smuzhiyun static void __exit ftrace_direct_exit(void)
47*4882a593Smuzhiyun {
48*4882a593Smuzhiyun unregister_ftrace_direct((unsigned long)handle_mm_fault,
49*4882a593Smuzhiyun (unsigned long)my_tramp);
50*4882a593Smuzhiyun }
51*4882a593Smuzhiyun
52*4882a593Smuzhiyun module_init(ftrace_direct_init);
53*4882a593Smuzhiyun module_exit(ftrace_direct_exit);
54*4882a593Smuzhiyun
55*4882a593Smuzhiyun MODULE_AUTHOR("Steven Rostedt");
56*4882a593Smuzhiyun MODULE_DESCRIPTION("Another example use case of using register_ftrace_direct()");
57*4882a593Smuzhiyun MODULE_LICENSE("GPL");
58