CoCalc -- ftrace-direct-multi.c

GitHub Repository: torvalds/linux
Path: blob/master/samples/ftrace/ftrace-direct-multi.c
²⁶²⁷⁸ views
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
#if !defined(CONFIG_ARM64) && !defined(CONFIG_PPC32)
8
#include <asm/asm-offsets.h>
9
#endif
10

11
extern void my_direct_func(unsigned long ip);
12

13
void my_direct_func(unsigned long ip)
14
{
15
	trace_printk("ip %lx\n", ip);
16
}
17

18
extern void my_tramp(void *);
19

20
#ifdef CONFIG_RISCV
21
#include <asm/asm.h>
22

23
asm (
24
"       .pushsection    .text, \"ax\", @progbits\n"
25
"       .type           my_tramp, @function\n"
26
"       .globl          my_tramp\n"
27
"   my_tramp:\n"
28
"       addi	sp,sp,-3*"SZREG"\n"
29
"       "REG_S"	a0,0*"SZREG"(sp)\n"
30
"       "REG_S"	t0,1*"SZREG"(sp)\n"
31
"       "REG_S"	ra,2*"SZREG"(sp)\n"
32
"       mv	a0,t0\n"
33
"       call	my_direct_func\n"
34
"       "REG_L"	a0,0*"SZREG"(sp)\n"
35
"       "REG_L"	t0,1*"SZREG"(sp)\n"
36
"       "REG_L"	ra,2*"SZREG"(sp)\n"
37
"       addi	sp,sp,3*"SZREG"\n"
38
"       jr	t0\n"
39
"       .size           my_tramp, .-my_tramp\n"
40
"       .popsection\n"
41
);
42

43
#endif /* CONFIG_RISCV */
44

45
#ifdef CONFIG_X86_64
46

47
#include <asm/ibt.h>
48
#include <asm/nospec-branch.h>
49

50
asm (
51
"	.pushsection    .text, \"ax\", @progbits\n"
52
"	.type		my_tramp, @function\n"
53
"	.globl		my_tramp\n"
54
"   my_tramp:"
55
	ASM_ENDBR
56
"	pushq %rbp\n"
57
"	movq %rsp, %rbp\n"
58
	CALL_DEPTH_ACCOUNT
59
"	pushq %rdi\n"
60
"	movq 8(%rbp), %rdi\n"
61
"	call my_direct_func\n"
62
"	popq %rdi\n"
63
"	leave\n"
64
	ASM_RET
65
"	.size		my_tramp, .-my_tramp\n"
66
"	.popsection\n"
67
);
68

69
#endif /* CONFIG_X86_64 */
70

71
#ifdef CONFIG_S390
72

73
asm (
74
"	.pushsection	.text, \"ax\", @progbits\n"
75
"	.type		my_tramp, @function\n"
76
"	.globl		my_tramp\n"
77
"   my_tramp:"
78
"	lgr		%r1,%r15\n"
79
"	stmg		%r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
80
"	stg		%r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
81
"	aghi		%r15,"__stringify(-STACK_FRAME_OVERHEAD)"\n"
82
"	stg		%r1,"__stringify(__SF_BACKCHAIN)"(%r15)\n"
83
"	lgr		%r2,%r0\n"
84
"	brasl		%r14,my_direct_func\n"
85
"	aghi		%r15,"__stringify(STACK_FRAME_OVERHEAD)"\n"
86
"	lmg		%r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
87
"	lg		%r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
88
"	lgr		%r1,%r0\n"
89
"	br		%r1\n"
90
"	.size		my_tramp, .-my_tramp\n"
91
"	.popsection\n"
92
);
93

94
#endif /* CONFIG_S390 */
95

96
#ifdef CONFIG_ARM64
97

98
asm (
99
"	.pushsection	.text, \"ax\", @progbits\n"
100
"	.type		my_tramp, @function\n"
101
"	.globl		my_tramp\n"
102
"   my_tramp:"
103
"	hint	34\n" // bti	c
104
"	sub	sp, sp, #32\n"
105
"	stp	x9, x30, [sp]\n"
106
"	str	x0, [sp, #16]\n"
107
"	mov	x0, x30\n"
108
"	bl	my_direct_func\n"
109
"	ldp	x30, x9, [sp]\n"
110
"	ldr	x0, [sp, #16]\n"
111
"	add	sp, sp, #32\n"
112
"	ret	x9\n"
113
"	.size		my_tramp, .-my_tramp\n"
114
"	.popsection\n"
115
);
116

117
#endif /* CONFIG_ARM64 */
118

119
#ifdef CONFIG_LOONGARCH
120

121
#include <asm/asm.h>
122
asm (
123
"	.pushsection	.text, \"ax\", @progbits\n"
124
"	.type		my_tramp, @function\n"
125
"	.globl		my_tramp\n"
126
"   my_tramp:\n"
127
"	addi.d	$sp, $sp, -32\n"
128
"	st.d	$a0, $sp, 0\n"
129
"	st.d	$t0, $sp, 8\n"
130
"	st.d	$ra, $sp, 16\n"
131
"	move	$a0, $t0\n"
132
"	bl	my_direct_func\n"
133
"	ld.d	$a0, $sp, 0\n"
134
"	ld.d	$t0, $sp, 8\n"
135
"	ld.d	$ra, $sp, 16\n"
136
"	addi.d	$sp, $sp, 32\n"
137
"	jr	$t0\n"
138
"	.size		my_tramp, .-my_tramp\n"
139
"	.popsection\n"
140
);
141

142
#endif /* CONFIG_LOONGARCH */
143

144
#ifdef CONFIG_PPC
145
#include <asm/ppc_asm.h>
146

147
#ifdef CONFIG_PPC64
148
#define STACK_FRAME_SIZE 48
149
#else
150
#define STACK_FRAME_SIZE 24
151
#endif
152

153
#if defined(CONFIG_PPC64_ELF_ABI_V2) && !defined(CONFIG_PPC_KERNEL_PCREL)
154
#define PPC64_TOC_SAVE_AND_UPDATE			\
155
"	std		2, 24(1)\n"			\
156
"	bcl		20, 31, 1f\n"			\
157
"   1:	mflr		12\n"				\
158
"	ld		2, (99f - 1b)(12)\n"
159
#define PPC64_TOC_RESTORE				\
160
"	ld		2, 24(1)\n"
161
#define PPC64_TOC					\
162
"   99:	.quad		.TOC.@tocbase\n"
163
#else
164
#define PPC64_TOC_SAVE_AND_UPDATE ""
165
#define PPC64_TOC_RESTORE ""
166
#define PPC64_TOC ""
167
#endif
168

169
#ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE
170
#define PPC_FTRACE_RESTORE_LR				\
171
	PPC_LL"		0, "__stringify(PPC_LR_STKOFF)"(1)\n"	\
172
"	mtlr		0\n"
173
#define PPC_FTRACE_RET					\
174
"	blr\n"
175
#define PPC_FTRACE_RECOVER_IP				\
176
"	lwz		8, 4(3)\n"			\
177
"	li		9, 6\n"				\
178
"	slw		8, 8, 9\n"			\
179
"	sraw		8, 8, 9\n"			\
180
"	add		3, 3, 8\n"			\
181
"	addi		3, 3, 4\n"
182
#else
183
#define PPC_FTRACE_RESTORE_LR				\
184
	PPC_LL"		0, "__stringify(PPC_LR_STKOFF)"(1)\n"	\
185
"	mtctr		0\n"
186
#define PPC_FTRACE_RET					\
187
"	mtlr		0\n"				\
188
"	bctr\n"
189
#define PPC_FTRACE_RECOVER_IP ""
190
#endif
191

192
asm (
193
"	.pushsection	.text, \"ax\", @progbits\n"
194
"	.type		my_tramp, @function\n"
195
"	.globl		my_tramp\n"
196
"   my_tramp:\n"
197
	PPC_STL"	0, "__stringify(PPC_LR_STKOFF)"(1)\n"
198
	PPC_STLU"	1, -"__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"
199
"	mflr		0\n"
200
	PPC_STL"	0, "__stringify(PPC_LR_STKOFF)"(1)\n"
201
	PPC_STLU"	1, -"__stringify(STACK_FRAME_SIZE)"(1)\n"
202
	PPC64_TOC_SAVE_AND_UPDATE
203
	PPC_STL"	3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"
204
"	mr		3, 0\n"
205
	PPC_FTRACE_RECOVER_IP
206
"	bl		my_direct_func\n"
207
	PPC_LL"		3, "__stringify(STACK_FRAME_MIN_SIZE)"(1)\n"
208
	PPC64_TOC_RESTORE
209
"	addi		1, 1, "__stringify(STACK_FRAME_SIZE)"\n"
210
	PPC_FTRACE_RESTORE_LR
211
"	addi		1, 1, "__stringify(STACK_FRAME_MIN_SIZE)"\n"
212
	PPC_LL"		0, "__stringify(PPC_LR_STKOFF)"(1)\n"
213
	PPC_FTRACE_RET
214
	PPC64_TOC
215
"	.size		my_tramp, .-my_tramp\n"
216
"	.popsection\n"
217
);
218

219
#endif /* CONFIG_PPC */
220

221
static struct ftrace_ops direct;
222

223
static int __init ftrace_direct_multi_init(void)
224
{
225
	ftrace_set_filter_ip(&direct, (unsigned long) wake_up_process, 0, 0);
226
	ftrace_set_filter_ip(&direct, (unsigned long) schedule, 0, 0);
227

228
	return register_ftrace_direct(&direct, (unsigned long) my_tramp);
229
}
230

231
static void __exit ftrace_direct_multi_exit(void)
232
{
233
	unregister_ftrace_direct(&direct, (unsigned long) my_tramp, true);
234
}
235

236
module_init(ftrace_direct_multi_init);
237
module_exit(ftrace_direct_multi_exit);
238

239
MODULE_AUTHOR("Jiri Olsa");
240
MODULE_DESCRIPTION("Example use case of using register_ftrace_direct_multi()");
241
MODULE_LICENSE("GPL");
242

243
Product

Resources

Company
