GNU Linux-libre 5.19-rc6-gnu
[releases.git] / samples / ftrace / ftrace-direct-multi.c
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 #include <asm/asm-offsets.h>
8
9 extern void my_direct_func(unsigned long ip);
10
11 void my_direct_func(unsigned long ip)
12 {
13         trace_printk("ip %lx\n", ip);
14 }
15
16 extern void my_tramp(void *);
17
18 #ifdef CONFIG_X86_64
19
20 #include <asm/ibt.h>
21
22 asm (
23 "       .pushsection    .text, \"ax\", @progbits\n"
24 "       .type           my_tramp, @function\n"
25 "       .globl          my_tramp\n"
26 "   my_tramp:"
27         ASM_ENDBR
28 "       pushq %rbp\n"
29 "       movq %rsp, %rbp\n"
30 "       pushq %rdi\n"
31 "       movq 8(%rbp), %rdi\n"
32 "       call my_direct_func\n"
33 "       popq %rdi\n"
34 "       leave\n"
35         ASM_RET
36 "       .size           my_tramp, .-my_tramp\n"
37 "       .popsection\n"
38 );
39
40 #endif /* CONFIG_X86_64 */
41
42 #ifdef CONFIG_S390
43
44 asm (
45 "       .pushsection    .text, \"ax\", @progbits\n"
46 "       .type           my_tramp, @function\n"
47 "       .globl          my_tramp\n"
48 "   my_tramp:"
49 "       lgr             %r1,%r15\n"
50 "       stmg            %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
51 "       stg             %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
52 "       aghi            %r15,"__stringify(-STACK_FRAME_OVERHEAD)"\n"
53 "       stg             %r1,"__stringify(__SF_BACKCHAIN)"(%r15)\n"
54 "       lgr             %r2,%r0\n"
55 "       brasl           %r14,my_direct_func\n"
56 "       aghi            %r15,"__stringify(STACK_FRAME_OVERHEAD)"\n"
57 "       lmg             %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
58 "       lg              %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
59 "       lgr             %r1,%r0\n"
60 "       br              %r1\n"
61 "       .size           my_tramp, .-my_tramp\n"
62 "       .popsection\n"
63 );
64
65 #endif /* CONFIG_S390 */
66
67 static struct ftrace_ops direct;
68
69 static int __init ftrace_direct_multi_init(void)
70 {
71         ftrace_set_filter_ip(&direct, (unsigned long) wake_up_process, 0, 0);
72         ftrace_set_filter_ip(&direct, (unsigned long) schedule, 0, 0);
73
74         return register_ftrace_direct_multi(&direct, (unsigned long) my_tramp);
75 }
76
77 static void __exit ftrace_direct_multi_exit(void)
78 {
79         unregister_ftrace_direct_multi(&direct, (unsigned long) my_tramp);
80 }
81
82 module_init(ftrace_direct_multi_init);
83 module_exit(ftrace_direct_multi_exit);
84
85 MODULE_AUTHOR("Jiri Olsa");
86 MODULE_DESCRIPTION("Example use case of using register_ftrace_direct_multi()");
87 MODULE_LICENSE("GPL");