tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
9extern void my_direct_func(unsigned long ip);
10
11void my_direct_func(unsigned long ip)
12{
13 trace_printk("ip %lx\n", ip);
14}
15
16extern void my_tramp(void *);
17
18#ifdef CONFIG_X86_64
19
20#include <asm/ibt.h>
21
22asm (
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
44asm (
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
67static struct ftrace_ops direct;
68
69static 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
77static void __exit ftrace_direct_multi_exit(void)
78{
79 unregister_ftrace_direct_multi(&direct, (unsigned long) my_tramp);
80}
81
82module_init(ftrace_direct_multi_init);
83module_exit(ftrace_direct_multi_exit);
84
85MODULE_AUTHOR("Jiri Olsa");
86MODULE_DESCRIPTION("Example use case of using register_ftrace_direct_multi()");
87MODULE_LICENSE("GPL");