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1// SPDX-License-Identifier: GPL-2.0-only
2#include <linux/module.h>
3#include <linux/kthread.h>
4#include <linux/ftrace.h>
5#ifndef CONFIG_ARM64
6#include <asm/asm-offsets.h>
7#endif
8
9extern void my_direct_func1(unsigned long ip);
10extern void my_direct_func2(unsigned long ip);
11
12void my_direct_func1(unsigned long ip)
13{
14 trace_printk("my direct func1 ip %lx\n", ip);
15}
16
17void my_direct_func2(unsigned long ip)
18{
19 trace_printk("my direct func2 ip %lx\n", ip);
20}
21
22extern void my_tramp1(void *);
23extern void my_tramp2(void *);
24
25#ifdef CONFIG_RISCV
26#include <asm/asm.h>
27
28asm (
29" .pushsection .text, \"ax\", @progbits\n"
30" .type my_tramp1, @function\n"
31" .globl my_tramp1\n"
32" my_tramp1:\n"
33" addi sp,sp,-3*"SZREG"\n"
34" "REG_S" a0,0*"SZREG"(sp)\n"
35" "REG_S" t0,1*"SZREG"(sp)\n"
36" "REG_S" ra,2*"SZREG"(sp)\n"
37" mv a0,t0\n"
38" call my_direct_func1\n"
39" "REG_L" a0,0*"SZREG"(sp)\n"
40" "REG_L" t0,1*"SZREG"(sp)\n"
41" "REG_L" ra,2*"SZREG"(sp)\n"
42" addi sp,sp,3*"SZREG"\n"
43" jr t0\n"
44" .size my_tramp1, .-my_tramp1\n"
45
46" .type my_tramp2, @function\n"
47" .globl my_tramp2\n"
48" my_tramp2:\n"
49" addi sp,sp,-3*"SZREG"\n"
50" "REG_S" a0,0*"SZREG"(sp)\n"
51" "REG_S" t0,1*"SZREG"(sp)\n"
52" "REG_S" ra,2*"SZREG"(sp)\n"
53" mv a0,t0\n"
54" call my_direct_func2\n"
55" "REG_L" a0,0*"SZREG"(sp)\n"
56" "REG_L" t0,1*"SZREG"(sp)\n"
57" "REG_L" ra,2*"SZREG"(sp)\n"
58" addi sp,sp,3*"SZREG"\n"
59" jr t0\n"
60" .size my_tramp2, .-my_tramp2\n"
61" .popsection\n"
62);
63
64#endif /* CONFIG_RISCV */
65
66#ifdef CONFIG_X86_64
67
68#include <asm/ibt.h>
69#include <asm/nospec-branch.h>
70
71asm (
72" .pushsection .text, \"ax\", @progbits\n"
73" .type my_tramp1, @function\n"
74" .globl my_tramp1\n"
75" my_tramp1:"
76 ASM_ENDBR
77" pushq %rbp\n"
78" movq %rsp, %rbp\n"
79 CALL_DEPTH_ACCOUNT
80" pushq %rdi\n"
81" movq 8(%rbp), %rdi\n"
82" call my_direct_func1\n"
83" popq %rdi\n"
84" leave\n"
85 ASM_RET
86" .size my_tramp1, .-my_tramp1\n"
87
88" .type my_tramp2, @function\n"
89" .globl my_tramp2\n"
90" my_tramp2:"
91 ASM_ENDBR
92" pushq %rbp\n"
93" movq %rsp, %rbp\n"
94 CALL_DEPTH_ACCOUNT
95" pushq %rdi\n"
96" movq 8(%rbp), %rdi\n"
97" call my_direct_func2\n"
98" popq %rdi\n"
99" leave\n"
100 ASM_RET
101" .size my_tramp2, .-my_tramp2\n"
102" .popsection\n"
103);
104
105#endif /* CONFIG_X86_64 */
106
107#ifdef CONFIG_S390
108
109asm (
110" .pushsection .text, \"ax\", @progbits\n"
111" .type my_tramp1, @function\n"
112" .globl my_tramp1\n"
113" my_tramp1:"
114" lgr %r1,%r15\n"
115" stmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
116" stg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
117" aghi %r15,"__stringify(-STACK_FRAME_OVERHEAD)"\n"
118" stg %r1,"__stringify(__SF_BACKCHAIN)"(%r15)\n"
119" lgr %r2,%r0\n"
120" brasl %r14,my_direct_func1\n"
121" aghi %r15,"__stringify(STACK_FRAME_OVERHEAD)"\n"
122" lmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
123" lg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
124" lgr %r1,%r0\n"
125" br %r1\n"
126" .size my_tramp1, .-my_tramp1\n"
127"\n"
128" .type my_tramp2, @function\n"
129" .globl my_tramp2\n"
130" my_tramp2:"
131" lgr %r1,%r15\n"
132" stmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
133" stg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
134" aghi %r15,"__stringify(-STACK_FRAME_OVERHEAD)"\n"
135" stg %r1,"__stringify(__SF_BACKCHAIN)"(%r15)\n"
136" lgr %r2,%r0\n"
137" brasl %r14,my_direct_func2\n"
138" aghi %r15,"__stringify(STACK_FRAME_OVERHEAD)"\n"
139" lmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
140" lg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
141" lgr %r1,%r0\n"
142" br %r1\n"
143" .size my_tramp2, .-my_tramp2\n"
144" .popsection\n"
145);
146
147#endif /* CONFIG_S390 */
148
149#ifdef CONFIG_ARM64
150
151asm (
152" .pushsection .text, \"ax\", @progbits\n"
153" .type my_tramp1, @function\n"
154" .globl my_tramp1\n"
155" my_tramp1:"
156" hint 34\n" // bti c
157" sub sp, sp, #32\n"
158" stp x9, x30, [sp]\n"
159" str x0, [sp, #16]\n"
160" mov x0, x30\n"
161" bl my_direct_func1\n"
162" ldp x30, x9, [sp]\n"
163" ldr x0, [sp, #16]\n"
164" add sp, sp, #32\n"
165" ret x9\n"
166" .size my_tramp1, .-my_tramp1\n"
167
168" .type my_tramp2, @function\n"
169" .globl my_tramp2\n"
170" my_tramp2:"
171" hint 34\n" // bti c
172" sub sp, sp, #32\n"
173" stp x9, x30, [sp]\n"
174" str x0, [sp, #16]\n"
175" mov x0, x30\n"
176" bl my_direct_func2\n"
177" ldp x30, x9, [sp]\n"
178" ldr x0, [sp, #16]\n"
179" add sp, sp, #32\n"
180" ret x9\n"
181" .size my_tramp2, .-my_tramp2\n"
182" .popsection\n"
183);
184
185#endif /* CONFIG_ARM64 */
186
187#ifdef CONFIG_LOONGARCH
188#include <asm/asm.h>
189
190asm (
191" .pushsection .text, \"ax\", @progbits\n"
192" .type my_tramp1, @function\n"
193" .globl my_tramp1\n"
194" my_tramp1:\n"
195" addi.d $sp, $sp, -32\n"
196" st.d $a0, $sp, 0\n"
197" st.d $t0, $sp, 8\n"
198" st.d $ra, $sp, 16\n"
199" move $a0, $t0\n"
200" bl my_direct_func1\n"
201" ld.d $a0, $sp, 0\n"
202" ld.d $t0, $sp, 8\n"
203" ld.d $ra, $sp, 16\n"
204" addi.d $sp, $sp, 32\n"
205" jr $t0\n"
206" .size my_tramp1, .-my_tramp1\n"
207
208" .type my_tramp2, @function\n"
209" .globl my_tramp2\n"
210" my_tramp2:\n"
211" addi.d $sp, $sp, -32\n"
212" st.d $a0, $sp, 0\n"
213" st.d $t0, $sp, 8\n"
214" st.d $ra, $sp, 16\n"
215" move $a0, $t0\n"
216" bl my_direct_func2\n"
217" ld.d $a0, $sp, 0\n"
218" ld.d $t0, $sp, 8\n"
219" ld.d $ra, $sp, 16\n"
220" addi.d $sp, $sp, 32\n"
221" jr $t0\n"
222" .size my_tramp2, .-my_tramp2\n"
223" .popsection\n"
224);
225
226#endif /* CONFIG_LOONGARCH */
227
228static unsigned long my_tramp = (unsigned long)my_tramp1;
229static unsigned long tramps[2] = {
230 (unsigned long)my_tramp1,
231 (unsigned long)my_tramp2,
232};
233
234static struct ftrace_ops direct;
235
236static int simple_thread(void *arg)
237{
238 static int t;
239 int ret = 0;
240
241 while (!kthread_should_stop()) {
242 set_current_state(TASK_INTERRUPTIBLE);
243 schedule_timeout(2 * HZ);
244
245 if (ret)
246 continue;
247 t ^= 1;
248 ret = modify_ftrace_direct(&direct, tramps[t]);
249 if (!ret)
250 my_tramp = tramps[t];
251 WARN_ON_ONCE(ret);
252 }
253
254 return 0;
255}
256
257static struct task_struct *simple_tsk;
258
259static int __init ftrace_direct_multi_init(void)
260{
261 int ret;
262
263 ftrace_set_filter_ip(&direct, (unsigned long) wake_up_process, 0, 0);
264 ftrace_set_filter_ip(&direct, (unsigned long) schedule, 0, 0);
265
266 ret = register_ftrace_direct(&direct, my_tramp);
267
268 if (!ret)
269 simple_tsk = kthread_run(simple_thread, NULL, "event-sample-fn");
270 return ret;
271}
272
273static void __exit ftrace_direct_multi_exit(void)
274{
275 kthread_stop(simple_tsk);
276 unregister_ftrace_direct(&direct, my_tramp, true);
277}
278
279module_init(ftrace_direct_multi_init);
280module_exit(ftrace_direct_multi_exit);
281
282MODULE_AUTHOR("Jiri Olsa");
283MODULE_DESCRIPTION("Example use case of using modify_ftrace_direct()");
284MODULE_LICENSE("GPL");
1// SPDX-License-Identifier: GPL-2.0-only
2#include <linux/module.h>
3#include <linux/kthread.h>
4#include <linux/ftrace.h>
5#ifndef CONFIG_ARM64
6#include <asm/asm-offsets.h>
7#endif
8
9extern void my_direct_func1(unsigned long ip);
10extern void my_direct_func2(unsigned long ip);
11
12void my_direct_func1(unsigned long ip)
13{
14 trace_printk("my direct func1 ip %lx\n", ip);
15}
16
17void my_direct_func2(unsigned long ip)
18{
19 trace_printk("my direct func2 ip %lx\n", ip);
20}
21
22extern void my_tramp1(void *);
23extern void my_tramp2(void *);
24
25#ifdef CONFIG_RISCV
26#include <asm/asm.h>
27
28asm (
29" .pushsection .text, \"ax\", @progbits\n"
30" .type my_tramp1, @function\n"
31" .globl my_tramp1\n"
32" my_tramp1:\n"
33" addi sp,sp,-3*"SZREG"\n"
34" "REG_S" a0,0*"SZREG"(sp)\n"
35" "REG_S" t0,1*"SZREG"(sp)\n"
36" "REG_S" ra,2*"SZREG"(sp)\n"
37" mv a0,t0\n"
38" call my_direct_func1\n"
39" "REG_L" a0,0*"SZREG"(sp)\n"
40" "REG_L" t0,1*"SZREG"(sp)\n"
41" "REG_L" ra,2*"SZREG"(sp)\n"
42" addi sp,sp,3*"SZREG"\n"
43" jr t0\n"
44" .size my_tramp1, .-my_tramp1\n"
45
46" .type my_tramp2, @function\n"
47" .globl my_tramp2\n"
48" my_tramp2:\n"
49" addi sp,sp,-3*"SZREG"\n"
50" "REG_S" a0,0*"SZREG"(sp)\n"
51" "REG_S" t0,1*"SZREG"(sp)\n"
52" "REG_S" ra,2*"SZREG"(sp)\n"
53" mv a0,t0\n"
54" call my_direct_func2\n"
55" "REG_L" a0,0*"SZREG"(sp)\n"
56" "REG_L" t0,1*"SZREG"(sp)\n"
57" "REG_L" ra,2*"SZREG"(sp)\n"
58" addi sp,sp,3*"SZREG"\n"
59" jr t0\n"
60" .size my_tramp2, .-my_tramp2\n"
61" .popsection\n"
62);
63
64#endif /* CONFIG_RISCV */
65
66#ifdef CONFIG_X86_64
67
68#include <asm/ibt.h>
69#include <asm/nospec-branch.h>
70
71asm (
72" .pushsection .text, \"ax\", @progbits\n"
73" .type my_tramp1, @function\n"
74" .globl my_tramp1\n"
75" my_tramp1:"
76 ASM_ENDBR
77" pushq %rbp\n"
78" movq %rsp, %rbp\n"
79 CALL_DEPTH_ACCOUNT
80" pushq %rdi\n"
81" movq 8(%rbp), %rdi\n"
82" call my_direct_func1\n"
83" popq %rdi\n"
84" leave\n"
85 ASM_RET
86" .size my_tramp1, .-my_tramp1\n"
87
88" .type my_tramp2, @function\n"
89" .globl my_tramp2\n"
90" my_tramp2:"
91 ASM_ENDBR
92" pushq %rbp\n"
93" movq %rsp, %rbp\n"
94 CALL_DEPTH_ACCOUNT
95" pushq %rdi\n"
96" movq 8(%rbp), %rdi\n"
97" call my_direct_func2\n"
98" popq %rdi\n"
99" leave\n"
100 ASM_RET
101" .size my_tramp2, .-my_tramp2\n"
102" .popsection\n"
103);
104
105#endif /* CONFIG_X86_64 */
106
107#ifdef CONFIG_S390
108
109asm (
110" .pushsection .text, \"ax\", @progbits\n"
111" .type my_tramp1, @function\n"
112" .globl my_tramp1\n"
113" my_tramp1:"
114" lgr %r1,%r15\n"
115" stmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
116" stg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
117" aghi %r15,"__stringify(-STACK_FRAME_OVERHEAD)"\n"
118" stg %r1,"__stringify(__SF_BACKCHAIN)"(%r15)\n"
119" lgr %r2,%r0\n"
120" brasl %r14,my_direct_func1\n"
121" aghi %r15,"__stringify(STACK_FRAME_OVERHEAD)"\n"
122" lmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
123" lg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
124" lgr %r1,%r0\n"
125" br %r1\n"
126" .size my_tramp1, .-my_tramp1\n"
127"\n"
128" .type my_tramp2, @function\n"
129" .globl my_tramp2\n"
130" my_tramp2:"
131" lgr %r1,%r15\n"
132" stmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
133" stg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
134" aghi %r15,"__stringify(-STACK_FRAME_OVERHEAD)"\n"
135" stg %r1,"__stringify(__SF_BACKCHAIN)"(%r15)\n"
136" lgr %r2,%r0\n"
137" brasl %r14,my_direct_func2\n"
138" aghi %r15,"__stringify(STACK_FRAME_OVERHEAD)"\n"
139" lmg %r0,%r5,"__stringify(__SF_GPRS)"(%r15)\n"
140" lg %r14,"__stringify(__SF_GPRS+8*8)"(%r15)\n"
141" lgr %r1,%r0\n"
142" br %r1\n"
143" .size my_tramp2, .-my_tramp2\n"
144" .popsection\n"
145);
146
147#endif /* CONFIG_S390 */
148
149#ifdef CONFIG_ARM64
150
151asm (
152" .pushsection .text, \"ax\", @progbits\n"
153" .type my_tramp1, @function\n"
154" .globl my_tramp1\n"
155" my_tramp1:"
156" hint 34\n" // bti c
157" sub sp, sp, #32\n"
158" stp x9, x30, [sp]\n"
159" str x0, [sp, #16]\n"
160" mov x0, x30\n"
161" bl my_direct_func1\n"
162" ldp x30, x9, [sp]\n"
163" ldr x0, [sp, #16]\n"
164" add sp, sp, #32\n"
165" ret x9\n"
166" .size my_tramp1, .-my_tramp1\n"
167
168" .type my_tramp2, @function\n"
169" .globl my_tramp2\n"
170" my_tramp2:"
171" hint 34\n" // bti c
172" sub sp, sp, #32\n"
173" stp x9, x30, [sp]\n"
174" str x0, [sp, #16]\n"
175" mov x0, x30\n"
176" bl my_direct_func2\n"
177" ldp x30, x9, [sp]\n"
178" ldr x0, [sp, #16]\n"
179" add sp, sp, #32\n"
180" ret x9\n"
181" .size my_tramp2, .-my_tramp2\n"
182" .popsection\n"
183);
184
185#endif /* CONFIG_ARM64 */
186
187#ifdef CONFIG_LOONGARCH
188#include <asm/asm.h>
189
190asm (
191" .pushsection .text, \"ax\", @progbits\n"
192" .type my_tramp1, @function\n"
193" .globl my_tramp1\n"
194" my_tramp1:\n"
195" addi.d $sp, $sp, -32\n"
196" st.d $a0, $sp, 0\n"
197" st.d $t0, $sp, 8\n"
198" st.d $ra, $sp, 16\n"
199" move $a0, $t0\n"
200" bl my_direct_func1\n"
201" ld.d $a0, $sp, 0\n"
202" ld.d $t0, $sp, 8\n"
203" ld.d $ra, $sp, 16\n"
204" addi.d $sp, $sp, 32\n"
205" jr $t0\n"
206" .size my_tramp1, .-my_tramp1\n"
207
208" .type my_tramp2, @function\n"
209" .globl my_tramp2\n"
210" my_tramp2:\n"
211" addi.d $sp, $sp, -32\n"
212" st.d $a0, $sp, 0\n"
213" st.d $t0, $sp, 8\n"
214" st.d $ra, $sp, 16\n"
215" move $a0, $t0\n"
216" bl my_direct_func2\n"
217" ld.d $a0, $sp, 0\n"
218" ld.d $t0, $sp, 8\n"
219" ld.d $ra, $sp, 16\n"
220" addi.d $sp, $sp, 32\n"
221" jr $t0\n"
222" .size my_tramp2, .-my_tramp2\n"
223" .popsection\n"
224);
225
226#endif /* CONFIG_LOONGARCH */
227
228static unsigned long my_tramp = (unsigned long)my_tramp1;
229static unsigned long tramps[2] = {
230 (unsigned long)my_tramp1,
231 (unsigned long)my_tramp2,
232};
233
234static struct ftrace_ops direct;
235
236static int simple_thread(void *arg)
237{
238 static int t;
239 int ret = 0;
240
241 while (!kthread_should_stop()) {
242 set_current_state(TASK_INTERRUPTIBLE);
243 schedule_timeout(2 * HZ);
244
245 if (ret)
246 continue;
247 t ^= 1;
248 ret = modify_ftrace_direct(&direct, tramps[t]);
249 if (!ret)
250 my_tramp = tramps[t];
251 WARN_ON_ONCE(ret);
252 }
253
254 return 0;
255}
256
257static struct task_struct *simple_tsk;
258
259static int __init ftrace_direct_multi_init(void)
260{
261 int ret;
262
263 ftrace_set_filter_ip(&direct, (unsigned long) wake_up_process, 0, 0);
264 ftrace_set_filter_ip(&direct, (unsigned long) schedule, 0, 0);
265
266 ret = register_ftrace_direct(&direct, my_tramp);
267
268 if (!ret)
269 simple_tsk = kthread_run(simple_thread, NULL, "event-sample-fn");
270 return ret;
271}
272
273static void __exit ftrace_direct_multi_exit(void)
274{
275 kthread_stop(simple_tsk);
276 unregister_ftrace_direct(&direct, my_tramp, true);
277}
278
279module_init(ftrace_direct_multi_init);
280module_exit(ftrace_direct_multi_exit);
281
282MODULE_AUTHOR("Jiri Olsa");
283MODULE_DESCRIPTION("Example use case of using modify_ftrace_direct()");
284MODULE_LICENSE("GPL");