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