1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
|
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/module.h>
#include <linux/mm.h> /* for handle_mm_fault() */
#include <linux/ftrace.h>
#ifndef CONFIG_ARM64
#include <asm/asm-offsets.h>
#endif
extern void my_direct_func(struct vm_area_struct *vma, unsigned long address,
unsigned int flags, struct pt_regs *regs);
void my_direct_func(struct vm_area_struct *vma, unsigned long address,
unsigned int flags, struct pt_regs *regs)
{
trace_printk("handle mm fault vma=%p address=%lx flags=%x regs=%p\n",
vma, address, flags, regs);
}
extern void my_tramp(void *);
#ifdef CONFIG_X86_64
#include <asm/ibt.h>
#include <asm/nospec-branch.h>
asm (
" .pushsection .text, \"ax\", @progbits\n"
" .type my_tramp, @function\n"
" .globl my_tramp\n"
" my_tramp:"
ASM_ENDBR
" pushq %rbp\n"
" movq %rsp, %rbp\n"
CALL_DEPTH_ACCOUNT
" pushq %rdi\n"
" pushq %rsi\n"
" pushq %rdx\n"
" pushq %rcx\n"
" call my_direct_func\n"
" popq %rcx\n"
" popq %rdx\n"
" popq %rsi\n"
" popq %rdi\n"
" leave\n"
ASM_RET
" .size my_tramp, .-my_tramp\n"
" .popsection\n"
);
#endif /* CONFIG_X86_64 */
#ifdef CONFIG_S390
asm (
" .pushsection .text, \"ax\", @progbits\n"
" .type my_tramp, @function\n"
" .globl my_tramp\n"
" my_tramp:"
" lgr %r1,%r15\n"
" stmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
" stg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
" aghi %r15,"__stringify(-STACK_FRAME_OVERHEAD)"\n"
" stg %r1,"__stringify(__SF_BACKCHAIN)"(%r15)\n"
" brasl %r14,my_direct_func\n"
" aghi %r15,"__stringify(STACK_FRAME_OVERHEAD)"\n"
" lmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
" lg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
" lgr %r1,%r0\n"
" br %r1\n"
" .size my_tramp, .-my_tramp\n"
" .popsection\n"
);
#endif /* CONFIG_S390 */
#ifdef CONFIG_ARM64
asm (
" .pushsection .text, \"ax\", @progbits\n"
" .type my_tramp, @function\n"
" .globl my_tramp\n"
" my_tramp:"
" hint 34\n" // bti c
" sub sp, sp, #48\n"
" stp x9, x30, [sp]\n"
" stp x0, x1, [sp, #16]\n"
" stp x2, x3, [sp, #32]\n"
" bl my_direct_func\n"
" ldp x30, x9, [sp]\n"
" ldp x0, x1, [sp, #16]\n"
" ldp x2, x3, [sp, #32]\n"
" add sp, sp, #48\n"
" ret x9\n"
" .size my_tramp, .-my_tramp\n"
" .popsection\n"
);
#endif /* CONFIG_ARM64 */
#ifdef CONFIG_LOONGARCH
asm (
" .pushsection .text, \"ax\", @progbits\n"
" .type my_tramp, @function\n"
" .globl my_tramp\n"
" my_tramp:\n"
" addi.d $sp, $sp, -48\n"
" st.d $a0, $sp, 0\n"
" st.d $a1, $sp, 8\n"
" st.d $a2, $sp, 16\n"
" st.d $t0, $sp, 24\n"
" st.d $ra, $sp, 32\n"
" bl my_direct_func\n"
" ld.d $a0, $sp, 0\n"
" ld.d $a1, $sp, 8\n"
" ld.d $a2, $sp, 16\n"
" ld.d $t0, $sp, 24\n"
" ld.d $ra, $sp, 32\n"
" addi.d $sp, $sp, 48\n"
" jr $t0\n"
" .size my_tramp, .-my_tramp\n"
" .popsection\n"
);
#endif /* CONFIG_LOONGARCH */
static struct ftrace_ops direct;
static int __init ftrace_direct_init(void)
{
ftrace_set_filter_ip(&direct, (unsigned long) handle_mm_fault, 0, 0);
return register_ftrace_direct(&direct, (unsigned long) my_tramp);
}
static void __exit ftrace_direct_exit(void)
{
unregister_ftrace_direct(&direct, (unsigned long)my_tramp, true);
}
module_init(ftrace_direct_init);
module_exit(ftrace_direct_exit);
MODULE_AUTHOR("Steven Rostedt");
MODULE_DESCRIPTION("Another example use case of using register_ftrace_direct()");
MODULE_LICENSE("GPL");
|
