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156473a0 SRV |
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 | ||
73d72bc4 JO |
7 | extern void my_direct_func(struct vm_area_struct *vma, |
8 | unsigned long address, unsigned int flags); | |
9 | ||
156473a0 SRV |
10 | void my_direct_func(struct vm_area_struct *vma, |
11 | unsigned long address, unsigned int flags) | |
12 | { | |
13 | trace_printk("handle mm fault vma=%p address=%lx flags=%x\n", | |
14 | vma, address, flags); | |
15 | } | |
16 | ||
17 | extern void my_tramp(void *); | |
18 | ||
19 | asm ( | |
20 | " .pushsection .text, \"ax\", @progbits\n" | |
9d907f1a | 21 | " .type my_tramp, @function\n" |
983df5f2 | 22 | " .globl my_tramp\n" |
156473a0 SRV |
23 | " my_tramp:" |
24 | " pushq %rbp\n" | |
25 | " movq %rsp, %rbp\n" | |
26 | " pushq %rdi\n" | |
27 | " pushq %rsi\n" | |
28 | " pushq %rdx\n" | |
29 | " call my_direct_func\n" | |
30 | " popq %rdx\n" | |
31 | " popq %rsi\n" | |
32 | " popq %rdi\n" | |
33 | " leave\n" | |
34 | " ret\n" | |
9d907f1a | 35 | " .size my_tramp, .-my_tramp\n" |
156473a0 SRV |
36 | " .popsection\n" |
37 | ); | |
38 | ||
39 | ||
40 | static int __init ftrace_direct_init(void) | |
41 | { | |
42 | return register_ftrace_direct((unsigned long)handle_mm_fault, | |
43 | (unsigned long)my_tramp); | |
44 | } | |
45 | ||
46 | static void __exit ftrace_direct_exit(void) | |
47 | { | |
48 | unregister_ftrace_direct((unsigned long)handle_mm_fault, | |
49 | (unsigned long)my_tramp); | |
50 | } | |
51 | ||
52 | module_init(ftrace_direct_init); | |
53 | module_exit(ftrace_direct_exit); | |
54 | ||
55 | MODULE_AUTHOR("Steven Rostedt"); | |
56 | MODULE_DESCRIPTION("Another example use case of using register_ftrace_direct()"); | |
57 | MODULE_LICENSE("GPL"); |